Adding upstream version 3.5.24.upstream/3.5.24upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

33 files changed, 12994 insertions, 0 deletions

diff --git a/src/smtp/.indent.pro b/src/smtp/.indent.pro
new file mode 120000
index 0000000..5c837ec
--- /dev/null
+++ b/src/smtp/.indent.pro
@@ -0,0 +1 @@
+../../.indent.pro
\ No newline at end of file
diff --git a/src/smtp/.printfck b/src/smtp/.printfck
new file mode 100644
index 0000000..66016ed
--- /dev/null
+++ b/src/smtp/.printfck
@@ -0,0 +1,25 @@
+been_here_xt	2	0
+bounce_append	5	0
+cleanup_out_format	1	0
+defer_append	5	0
+mail_command	1	0
+mail_print	1	0
+msg_error	0	0
+msg_fatal	0	0
+msg_info	0	0
+msg_panic	0	0
+msg_warn	0	0
+opened		4	0
+post_mail_fprintf	1	0
+qmgr_message_bounce	2	0
+rec_fprintf	2	0
+sent	4	0
+smtp_cmd	1	0
+smtp_mesg_fail	2	0
+smtp_printf	1	0
+smtp_rcpt_fail	3	0
+smtp_site_fail	2	0
+udp_syslog	1	0
+vstream_fprintf	1	0
+vstream_printf	0	0
+vstring_sprintf	1	0
diff --git a/src/smtp/Makefile.in b/src/smtp/Makefile.in
new file mode 100644
index 0000000..140192f
--- /dev/null
+++ b/src/smtp/Makefile.in
@@ -0,0 +1,871 @@
+SHELL	= /bin/sh
+SRCS	= smtp.c smtp_connect.c smtp_proto.c smtp_chat.c smtp_session.c \
+	smtp_addr.c smtp_trouble.c smtp_state.c smtp_rcpt.c smtp_tls_policy.c \
+	smtp_sasl_proto.c smtp_sasl_glue.c smtp_reuse.c smtp_map11.c \
+	smtp_sasl_auth_cache.c smtp_key.c smtp_misc.c
+OBJS	= smtp.o smtp_connect.o smtp_proto.o smtp_chat.o smtp_session.o \
+	smtp_addr.o smtp_trouble.o smtp_state.o smtp_rcpt.o smtp_tls_policy.o \
+	smtp_sasl_proto.o smtp_sasl_glue.o smtp_reuse.o smtp_map11.o \
+	smtp_sasl_auth_cache.o smtp_key.o smtp_misc.o
+HDRS	= smtp.h smtp_sasl.h smtp_addr.h smtp_reuse.h smtp_sasl_auth_cache.h
+TESTSRC	= 
+DEFS	= -I. -I$(INC_DIR) -D$(SYSTYPE)
+CFLAGS	= $(DEBUG) $(OPT) $(DEFS)
+TESTPROG= smtp_unalias smtp_map11
+PROG	= smtp
+INC_DIR	= ../../include
+LIBS	= ../../lib/lib$(LIB_PREFIX)master$(LIB_SUFFIX) \
+	../../lib/lib$(LIB_PREFIX)tls$(LIB_SUFFIX) \
+	../../lib/lib$(LIB_PREFIX)dns$(LIB_SUFFIX) \
+	../../lib/libxsasl.a \
+	../../lib/lib$(LIB_PREFIX)global$(LIB_SUFFIX) \
+	../../lib/lib$(LIB_PREFIX)util$(LIB_SUFFIX)
+
+.c.o:;	$(CC) $(CFLAGS) -c $*.c
+
+$(PROG):	$(OBJS) $(LIBS)
+	$(CC) $(CFLAGS) $(SHLIB_RPATH) -o $@ $(OBJS) $(LIBS) $(SYSLIBS)
+
+$(OBJS): ../../conf/makedefs.out
+
+Makefile: Makefile.in
+	cat ../../conf/makedefs.out $? >$@
+
+test:	$(TESTPROG)
+
+tests: smtp_map11_test
+
+root_tests:
+
+update: ../../libexec/$(PROG)
+
+../../libexec/$(PROG): $(PROG)
+	cp $(PROG) ../../libexec
+
+smtp.o:	smtp.c smtp_params.c lmtp_params.c
+
+lmtp_params.c: smtp_params.c
+	egrep -v -f smtp-only smtp_params.c | \
+	    sed 's/SMTP/LMTP/g; s/smtp_\([a-z]*_table\)/lmtp_\1/' >$@
+
+printfck: $(OBJS) $(PROG)
+	rm -rf printfck
+	mkdir printfck
+	cp *.h printfck
+	sed '1,/^# do not edit/!d' Makefile >printfck/Makefile
+	set -e; for i in *.c; do printfck -f .printfck $$i >printfck/$$i; done
+	cd printfck; make "INC_DIR=../../../include" `cd ..; ls *.o`
+
+lint:
+	lint $(DEFS) $(SRCS) $(LINTFIX)
+
+clean:
+	rm -f *.o *core $(PROG) $(TESTPROG) junk 
+	rm -rf printfck
+
+tidy:	clean
+
+smtp_unalias: smtp_unalias.c $(LIBS)
+	$(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIBS) $(SYSLIBS)
+
+smtp_map11: smtp_map11.c $(LIBS)
+	$(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIBS) $(SYSLIBS)
+
+smtp_map11_test: smtp_map11 smtp_map11.ref
+	$(SHLIB_ENV) $(VALGRIND) ./smtp_map11 <smtp_map11.in >smtp_map11.tmp 2>&1
+	diff smtp_map11.ref smtp_map11.tmp
+	rm -f smtp_map11.tmp
+
+depend: $(MAKES)
+	(sed '1,/^# do not edit/!d' Makefile.in; \
+	set -e; for i in [a-z][a-z0-9]*.c; do \
+	    $(CC) -E $(DEFS) $(INCL) $$i | grep -v '[<>]' | sed -n -e '/^# *1 *"\([^"]*\)".*/{' \
+	    -e 's//'`echo $$i|sed 's/c$$/o/'`': \1/' \
+	    -e 's/o: \.\//o: /' -e p -e '}' ; \
+	done | LANG=C sort -u) | grep -v '[.][o][:][ ][/]' >$$$$ && mv $$$$ Makefile.in
+	@$(EXPORT) make -f Makefile.in Makefile 1>&2
+
+# do not edit below this line - it is generated by 'make depend'
+lmtp_params.o: lmtp_params.c
+smtp.o: ../../include/argv.h
+smtp.o: ../../include/attr.h
+smtp.o: ../../include/byte_mask.h
+smtp.o: ../../include/check_arg.h
+smtp.o: ../../include/debug_peer.h
+smtp.o: ../../include/deliver_request.h
+smtp.o: ../../include/dict.h
+smtp.o: ../../include/dns.h
+smtp.o: ../../include/dsn.h
+smtp.o: ../../include/dsn_buf.h
+smtp.o: ../../include/ext_prop.h
+smtp.o: ../../include/flush_clnt.h
+smtp.o: ../../include/header_body_checks.h
+smtp.o: ../../include/header_opts.h
+smtp.o: ../../include/htable.h
+smtp.o: ../../include/iostuff.h
+smtp.o: ../../include/mail_conf.h
+smtp.o: ../../include/mail_params.h
+smtp.o: ../../include/mail_proto.h
+smtp.o: ../../include/mail_server.h
+smtp.o: ../../include/mail_version.h
+smtp.o: ../../include/maps.h
+smtp.o: ../../include/match_list.h
+smtp.o: ../../include/mime_state.h
+smtp.o: ../../include/msg.h
+smtp.o: ../../include/msg_stats.h
+smtp.o: ../../include/myaddrinfo.h
+smtp.o: ../../include/myflock.h
+smtp.o: ../../include/mymalloc.h
+smtp.o: ../../include/name_code.h
+smtp.o: ../../include/name_mask.h
+smtp.o: ../../include/nvtable.h
+smtp.o: ../../include/recipient_list.h
+smtp.o: ../../include/resolve_clnt.h
+smtp.o: ../../include/scache.h
+smtp.o: ../../include/sock_addr.h
+smtp.o: ../../include/string_list.h
+smtp.o: ../../include/stringops.h
+smtp.o: ../../include/sys_defs.h
+smtp.o: ../../include/tls.h
+smtp.o: ../../include/tls_proxy.h
+smtp.o: ../../include/tok822.h
+smtp.o: ../../include/vbuf.h
+smtp.o: ../../include/vstream.h
+smtp.o: ../../include/vstring.h
+smtp.o: lmtp_params.c
+smtp.o: smtp.c
+smtp.o: smtp.h
+smtp.o: smtp_params.c
+smtp.o: smtp_sasl.h
+smtp_addr.o: ../../include/argv.h
+smtp_addr.o: ../../include/attr.h
+smtp_addr.o: ../../include/check_arg.h
+smtp_addr.o: ../../include/deliver_request.h
+smtp_addr.o: ../../include/dict.h
+smtp_addr.o: ../../include/dns.h
+smtp_addr.o: ../../include/dsn.h
+smtp_addr.o: ../../include/dsn_buf.h
+smtp_addr.o: ../../include/header_body_checks.h
+smtp_addr.o: ../../include/header_opts.h
+smtp_addr.o: ../../include/htable.h
+smtp_addr.o: ../../include/inet_addr_list.h
+smtp_addr.o: ../../include/inet_proto.h
+smtp_addr.o: ../../include/mail_params.h
+smtp_addr.o: ../../include/maps.h
+smtp_addr.o: ../../include/match_list.h
+smtp_addr.o: ../../include/midna_domain.h
+smtp_addr.o: ../../include/mime_state.h
+smtp_addr.o: ../../include/msg.h
+smtp_addr.o: ../../include/msg_stats.h
+smtp_addr.o: ../../include/myaddrinfo.h
+smtp_addr.o: ../../include/myflock.h
+smtp_addr.o: ../../include/mymalloc.h
+smtp_addr.o: ../../include/name_code.h
+smtp_addr.o: ../../include/name_mask.h
+smtp_addr.o: ../../include/nvtable.h
+smtp_addr.o: ../../include/own_inet_addr.h
+smtp_addr.o: ../../include/recipient_list.h
+smtp_addr.o: ../../include/resolve_clnt.h
+smtp_addr.o: ../../include/scache.h
+smtp_addr.o: ../../include/sock_addr.h
+smtp_addr.o: ../../include/string_list.h
+smtp_addr.o: ../../include/stringops.h
+smtp_addr.o: ../../include/sys_defs.h
+smtp_addr.o: ../../include/tls.h
+smtp_addr.o: ../../include/tls_proxy.h
+smtp_addr.o: ../../include/tok822.h
+smtp_addr.o: ../../include/vbuf.h
+smtp_addr.o: ../../include/vstream.h
+smtp_addr.o: ../../include/vstring.h
+smtp_addr.o: smtp.h
+smtp_addr.o: smtp_addr.c
+smtp_addr.o: smtp_addr.h
+smtp_chat.o: ../../include/argv.h
+smtp_chat.o: ../../include/attr.h
+smtp_chat.o: ../../include/check_arg.h
+smtp_chat.o: ../../include/cleanup_user.h
+smtp_chat.o: ../../include/deliver_request.h
+smtp_chat.o: ../../include/dict.h
+smtp_chat.o: ../../include/dns.h
+smtp_chat.o: ../../include/dsn.h
+smtp_chat.o: ../../include/dsn_buf.h
+smtp_chat.o: ../../include/dsn_util.h
+smtp_chat.o: ../../include/header_body_checks.h
+smtp_chat.o: ../../include/header_opts.h
+smtp_chat.o: ../../include/htable.h
+smtp_chat.o: ../../include/int_filt.h
+smtp_chat.o: ../../include/iostuff.h
+smtp_chat.o: ../../include/line_wrap.h
+smtp_chat.o: ../../include/mail_addr.h
+smtp_chat.o: ../../include/mail_error.h
+smtp_chat.o: ../../include/mail_params.h
+smtp_chat.o: ../../include/mail_proto.h
+smtp_chat.o: ../../include/maps.h
+smtp_chat.o: ../../include/match_list.h
+smtp_chat.o: ../../include/mime_state.h
+smtp_chat.o: ../../include/msg.h
+smtp_chat.o: ../../include/msg_stats.h
+smtp_chat.o: ../../include/myaddrinfo.h
+smtp_chat.o: ../../include/myflock.h
+smtp_chat.o: ../../include/mymalloc.h
+smtp_chat.o: ../../include/name_code.h
+smtp_chat.o: ../../include/name_mask.h
+smtp_chat.o: ../../include/nvtable.h
+smtp_chat.o: ../../include/post_mail.h
+smtp_chat.o: ../../include/recipient_list.h
+smtp_chat.o: ../../include/resolve_clnt.h
+smtp_chat.o: ../../include/scache.h
+smtp_chat.o: ../../include/smtp_stream.h
+smtp_chat.o: ../../include/smtputf8.h
+smtp_chat.o: ../../include/sock_addr.h
+smtp_chat.o: ../../include/string_list.h
+smtp_chat.o: ../../include/stringops.h
+smtp_chat.o: ../../include/sys_defs.h
+smtp_chat.o: ../../include/tls.h
+smtp_chat.o: ../../include/tls_proxy.h
+smtp_chat.o: ../../include/tok822.h
+smtp_chat.o: ../../include/vbuf.h
+smtp_chat.o: ../../include/vstream.h
+smtp_chat.o: ../../include/vstring.h
+smtp_chat.o: smtp.h
+smtp_chat.o: smtp_chat.c
+smtp_connect.o: ../../include/argv.h
+smtp_connect.o: ../../include/attr.h
+smtp_connect.o: ../../include/check_arg.h
+smtp_connect.o: ../../include/deliver_pass.h
+smtp_connect.o: ../../include/deliver_request.h
+smtp_connect.o: ../../include/dict.h
+smtp_connect.o: ../../include/dns.h
+smtp_connect.o: ../../include/dsn.h
+smtp_connect.o: ../../include/dsn_buf.h
+smtp_connect.o: ../../include/header_body_checks.h
+smtp_connect.o: ../../include/header_opts.h
+smtp_connect.o: ../../include/host_port.h
+smtp_connect.o: ../../include/htable.h
+smtp_connect.o: ../../include/inet_addr_list.h
+smtp_connect.o: ../../include/inet_proto.h
+smtp_connect.o: ../../include/iostuff.h
+smtp_connect.o: ../../include/mail_addr.h
+smtp_connect.o: ../../include/mail_error.h
+smtp_connect.o: ../../include/mail_params.h
+smtp_connect.o: ../../include/mail_proto.h
+smtp_connect.o: ../../include/maps.h
+smtp_connect.o: ../../include/match_list.h
+smtp_connect.o: ../../include/mime_state.h
+smtp_connect.o: ../../include/msg.h
+smtp_connect.o: ../../include/msg_stats.h
+smtp_connect.o: ../../include/myaddrinfo.h
+smtp_connect.o: ../../include/myflock.h
+smtp_connect.o: ../../include/mymalloc.h
+smtp_connect.o: ../../include/name_code.h
+smtp_connect.o: ../../include/name_mask.h
+smtp_connect.o: ../../include/nvtable.h
+smtp_connect.o: ../../include/own_inet_addr.h
+smtp_connect.o: ../../include/recipient_list.h
+smtp_connect.o: ../../include/resolve_clnt.h
+smtp_connect.o: ../../include/sane_connect.h
+smtp_connect.o: ../../include/scache.h
+smtp_connect.o: ../../include/sock_addr.h
+smtp_connect.o: ../../include/split_at.h
+smtp_connect.o: ../../include/string_list.h
+smtp_connect.o: ../../include/stringops.h
+smtp_connect.o: ../../include/sys_defs.h
+smtp_connect.o: ../../include/timed_connect.h
+smtp_connect.o: ../../include/tls.h
+smtp_connect.o: ../../include/tls_proxy.h
+smtp_connect.o: ../../include/tok822.h
+smtp_connect.o: ../../include/vbuf.h
+smtp_connect.o: ../../include/vstream.h
+smtp_connect.o: ../../include/vstring.h
+smtp_connect.o: smtp.h
+smtp_connect.o: smtp_addr.h
+smtp_connect.o: smtp_connect.c
+smtp_connect.o: smtp_reuse.h
+smtp_key.o: ../../include/argv.h
+smtp_key.o: ../../include/attr.h
+smtp_key.o: ../../include/base64_code.h
+smtp_key.o: ../../include/check_arg.h
+smtp_key.o: ../../include/deliver_request.h
+smtp_key.o: ../../include/dict.h
+smtp_key.o: ../../include/dns.h
+smtp_key.o: ../../include/dsn.h
+smtp_key.o: ../../include/dsn_buf.h
+smtp_key.o: ../../include/header_body_checks.h
+smtp_key.o: ../../include/header_opts.h
+smtp_key.o: ../../include/htable.h
+smtp_key.o: ../../include/mail_params.h
+smtp_key.o: ../../include/maps.h
+smtp_key.o: ../../include/match_list.h
+smtp_key.o: ../../include/mime_state.h
+smtp_key.o: ../../include/msg.h
+smtp_key.o: ../../include/msg_stats.h
+smtp_key.o: ../../include/myaddrinfo.h
+smtp_key.o: ../../include/myflock.h
+smtp_key.o: ../../include/mymalloc.h
+smtp_key.o: ../../include/name_code.h
+smtp_key.o: ../../include/name_mask.h
+smtp_key.o: ../../include/nvtable.h
+smtp_key.o: ../../include/recipient_list.h
+smtp_key.o: ../../include/resolve_clnt.h
+smtp_key.o: ../../include/scache.h
+smtp_key.o: ../../include/sock_addr.h
+smtp_key.o: ../../include/string_list.h
+smtp_key.o: ../../include/sys_defs.h
+smtp_key.o: ../../include/tls.h
+smtp_key.o: ../../include/tls_proxy.h
+smtp_key.o: ../../include/tok822.h
+smtp_key.o: ../../include/vbuf.h
+smtp_key.o: ../../include/vstream.h
+smtp_key.o: ../../include/vstring.h
+smtp_key.o: smtp.h
+smtp_key.o: smtp_key.c
+smtp_map11.o: ../../include/argv.h
+smtp_map11.o: ../../include/attr.h
+smtp_map11.o: ../../include/check_arg.h
+smtp_map11.o: ../../include/deliver_request.h
+smtp_map11.o: ../../include/dict.h
+smtp_map11.o: ../../include/dns.h
+smtp_map11.o: ../../include/dsn.h
+smtp_map11.o: ../../include/dsn_buf.h
+smtp_map11.o: ../../include/header_body_checks.h
+smtp_map11.o: ../../include/header_opts.h
+smtp_map11.o: ../../include/htable.h
+smtp_map11.o: ../../include/mail_addr_form.h
+smtp_map11.o: ../../include/mail_addr_map.h
+smtp_map11.o: ../../include/maps.h
+smtp_map11.o: ../../include/match_list.h
+smtp_map11.o: ../../include/mime_state.h
+smtp_map11.o: ../../include/msg.h
+smtp_map11.o: ../../include/msg_stats.h
+smtp_map11.o: ../../include/myaddrinfo.h
+smtp_map11.o: ../../include/myflock.h
+smtp_map11.o: ../../include/mymalloc.h
+smtp_map11.o: ../../include/name_code.h
+smtp_map11.o: ../../include/name_mask.h
+smtp_map11.o: ../../include/nvtable.h
+smtp_map11.o: ../../include/quote_822_local.h
+smtp_map11.o: ../../include/quote_flags.h
+smtp_map11.o: ../../include/recipient_list.h
+smtp_map11.o: ../../include/resolve_clnt.h
+smtp_map11.o: ../../include/scache.h
+smtp_map11.o: ../../include/sock_addr.h
+smtp_map11.o: ../../include/string_list.h
+smtp_map11.o: ../../include/sys_defs.h
+smtp_map11.o: ../../include/tls.h
+smtp_map11.o: ../../include/tls_proxy.h
+smtp_map11.o: ../../include/tok822.h
+smtp_map11.o: ../../include/vbuf.h
+smtp_map11.o: ../../include/vstream.h
+smtp_map11.o: ../../include/vstring.h
+smtp_map11.o: smtp.h
+smtp_map11.o: smtp_map11.c
+smtp_misc.o: ../../include/argv.h
+smtp_misc.o: ../../include/attr.h
+smtp_misc.o: ../../include/check_arg.h
+smtp_misc.o: ../../include/deliver_request.h
+smtp_misc.o: ../../include/dict.h
+smtp_misc.o: ../../include/dns.h
+smtp_misc.o: ../../include/dsn.h
+smtp_misc.o: ../../include/dsn_buf.h
+smtp_misc.o: ../../include/ext_prop.h
+smtp_misc.o: ../../include/header_body_checks.h
+smtp_misc.o: ../../include/header_opts.h
+smtp_misc.o: ../../include/htable.h
+smtp_misc.o: ../../include/mail_params.h
+smtp_misc.o: ../../include/maps.h
+smtp_misc.o: ../../include/match_list.h
+smtp_misc.o: ../../include/mime_state.h
+smtp_misc.o: ../../include/msg_stats.h
+smtp_misc.o: ../../include/myaddrinfo.h
+smtp_misc.o: ../../include/myflock.h
+smtp_misc.o: ../../include/mymalloc.h
+smtp_misc.o: ../../include/name_code.h
+smtp_misc.o: ../../include/name_mask.h
+smtp_misc.o: ../../include/nvtable.h
+smtp_misc.o: ../../include/quote_821_local.h
+smtp_misc.o: ../../include/quote_822_local.h
+smtp_misc.o: ../../include/quote_flags.h
+smtp_misc.o: ../../include/recipient_list.h
+smtp_misc.o: ../../include/resolve_clnt.h
+smtp_misc.o: ../../include/scache.h
+smtp_misc.o: ../../include/sock_addr.h
+smtp_misc.o: ../../include/string_list.h
+smtp_misc.o: ../../include/sys_defs.h
+smtp_misc.o: ../../include/tls.h
+smtp_misc.o: ../../include/tls_proxy.h
+smtp_misc.o: ../../include/tok822.h
+smtp_misc.o: ../../include/vbuf.h
+smtp_misc.o: ../../include/vstream.h
+smtp_misc.o: ../../include/vstring.h
+smtp_misc.o: smtp.h
+smtp_misc.o: smtp_misc.c
+smtp_params.o: smtp_params.c
+smtp_proto.o: ../../include/argv.h
+smtp_proto.o: ../../include/attr.h
+smtp_proto.o: ../../include/bounce.h
+smtp_proto.o: ../../include/check_arg.h
+smtp_proto.o: ../../include/defer.h
+smtp_proto.o: ../../include/deliver_request.h
+smtp_proto.o: ../../include/dict.h
+smtp_proto.o: ../../include/dns.h
+smtp_proto.o: ../../include/dsn.h
+smtp_proto.o: ../../include/dsn_buf.h
+smtp_proto.o: ../../include/dsn_mask.h
+smtp_proto.o: ../../include/ehlo_mask.h
+smtp_proto.o: ../../include/ext_prop.h
+smtp_proto.o: ../../include/header_body_checks.h
+smtp_proto.o: ../../include/header_opts.h
+smtp_proto.o: ../../include/htable.h
+smtp_proto.o: ../../include/iostuff.h
+smtp_proto.o: ../../include/lex_822.h
+smtp_proto.o: ../../include/mail_addr_form.h
+smtp_proto.o: ../../include/mail_addr_map.h
+smtp_proto.o: ../../include/mail_params.h
+smtp_proto.o: ../../include/mail_proto.h
+smtp_proto.o: ../../include/mail_queue.h
+smtp_proto.o: ../../include/maps.h
+smtp_proto.o: ../../include/mark_corrupt.h
+smtp_proto.o: ../../include/match_list.h
+smtp_proto.o: ../../include/match_parent_style.h
+smtp_proto.o: ../../include/mime_state.h
+smtp_proto.o: ../../include/msg.h
+smtp_proto.o: ../../include/msg_stats.h
+smtp_proto.o: ../../include/myaddrinfo.h
+smtp_proto.o: ../../include/myflock.h
+smtp_proto.o: ../../include/mymalloc.h
+smtp_proto.o: ../../include/namadr_list.h
+smtp_proto.o: ../../include/name_code.h
+smtp_proto.o: ../../include/name_mask.h
+smtp_proto.o: ../../include/nvtable.h
+smtp_proto.o: ../../include/off_cvt.h
+smtp_proto.o: ../../include/quote_822_local.h
+smtp_proto.o: ../../include/quote_flags.h
+smtp_proto.o: ../../include/rec_type.h
+smtp_proto.o: ../../include/recipient_list.h
+smtp_proto.o: ../../include/record.h
+smtp_proto.o: ../../include/resolve_clnt.h
+smtp_proto.o: ../../include/scache.h
+smtp_proto.o: ../../include/smtp_stream.h
+smtp_proto.o: ../../include/smtputf8.h
+smtp_proto.o: ../../include/sock_addr.h
+smtp_proto.o: ../../include/split_at.h
+smtp_proto.o: ../../include/string_list.h
+smtp_proto.o: ../../include/stringops.h
+smtp_proto.o: ../../include/sys_defs.h
+smtp_proto.o: ../../include/tls.h
+smtp_proto.o: ../../include/tls_proxy.h
+smtp_proto.o: ../../include/tok822.h
+smtp_proto.o: ../../include/uxtext.h
+smtp_proto.o: ../../include/vbuf.h
+smtp_proto.o: ../../include/vstream.h
+smtp_proto.o: ../../include/vstring.h
+smtp_proto.o: ../../include/vstring_vstream.h
+smtp_proto.o: ../../include/xtext.h
+smtp_proto.o: smtp.h
+smtp_proto.o: smtp_proto.c
+smtp_proto.o: smtp_sasl.h
+smtp_rcpt.o: ../../include/argv.h
+smtp_rcpt.o: ../../include/attr.h
+smtp_rcpt.o: ../../include/bounce.h
+smtp_rcpt.o: ../../include/check_arg.h
+smtp_rcpt.o: ../../include/deliver_completed.h
+smtp_rcpt.o: ../../include/deliver_request.h
+smtp_rcpt.o: ../../include/dict.h
+smtp_rcpt.o: ../../include/dns.h
+smtp_rcpt.o: ../../include/dsn.h
+smtp_rcpt.o: ../../include/dsn_buf.h
+smtp_rcpt.o: ../../include/dsn_mask.h
+smtp_rcpt.o: ../../include/header_body_checks.h
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+smtp_rcpt.o: ../../include/htable.h
+smtp_rcpt.o: ../../include/mail_params.h
+smtp_rcpt.o: ../../include/maps.h
+smtp_rcpt.o: ../../include/match_list.h
+smtp_rcpt.o: ../../include/mime_state.h
+smtp_rcpt.o: ../../include/msg.h
+smtp_rcpt.o: ../../include/msg_stats.h
+smtp_rcpt.o: ../../include/myaddrinfo.h
+smtp_rcpt.o: ../../include/myflock.h
+smtp_rcpt.o: ../../include/mymalloc.h
+smtp_rcpt.o: ../../include/name_code.h
+smtp_rcpt.o: ../../include/name_mask.h
+smtp_rcpt.o: ../../include/nvtable.h
+smtp_rcpt.o: ../../include/recipient_list.h
+smtp_rcpt.o: ../../include/resolve_clnt.h
+smtp_rcpt.o: ../../include/scache.h
+smtp_rcpt.o: ../../include/sent.h
+smtp_rcpt.o: ../../include/sock_addr.h
+smtp_rcpt.o: ../../include/string_list.h
+smtp_rcpt.o: ../../include/stringops.h
+smtp_rcpt.o: ../../include/sys_defs.h
+smtp_rcpt.o: ../../include/tls.h
+smtp_rcpt.o: ../../include/tls_proxy.h
+smtp_rcpt.o: ../../include/tok822.h
+smtp_rcpt.o: ../../include/vbuf.h
+smtp_rcpt.o: ../../include/vstream.h
+smtp_rcpt.o: ../../include/vstring.h
+smtp_rcpt.o: smtp.h
+smtp_rcpt.o: smtp_rcpt.c
+smtp_reuse.o: ../../include/argv.h
+smtp_reuse.o: ../../include/attr.h
+smtp_reuse.o: ../../include/check_arg.h
+smtp_reuse.o: ../../include/deliver_request.h
+smtp_reuse.o: ../../include/dict.h
+smtp_reuse.o: ../../include/dns.h
+smtp_reuse.o: ../../include/dsn.h
+smtp_reuse.o: ../../include/dsn_buf.h
+smtp_reuse.o: ../../include/header_body_checks.h
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+smtp_reuse.o: ../../include/htable.h
+smtp_reuse.o: ../../include/mail_params.h
+smtp_reuse.o: ../../include/maps.h
+smtp_reuse.o: ../../include/match_list.h
+smtp_reuse.o: ../../include/mime_state.h
+smtp_reuse.o: ../../include/msg.h
+smtp_reuse.o: ../../include/msg_stats.h
+smtp_reuse.o: ../../include/myaddrinfo.h
+smtp_reuse.o: ../../include/myflock.h
+smtp_reuse.o: ../../include/mymalloc.h
+smtp_reuse.o: ../../include/name_code.h
+smtp_reuse.o: ../../include/name_mask.h
+smtp_reuse.o: ../../include/nvtable.h
+smtp_reuse.o: ../../include/recipient_list.h
+smtp_reuse.o: ../../include/resolve_clnt.h
+smtp_reuse.o: ../../include/scache.h
+smtp_reuse.o: ../../include/sock_addr.h
+smtp_reuse.o: ../../include/string_list.h
+smtp_reuse.o: ../../include/stringops.h
+smtp_reuse.o: ../../include/sys_defs.h
+smtp_reuse.o: ../../include/tls.h
+smtp_reuse.o: ../../include/tls_proxy.h
+smtp_reuse.o: ../../include/tok822.h
+smtp_reuse.o: ../../include/vbuf.h
+smtp_reuse.o: ../../include/vstream.h
+smtp_reuse.o: ../../include/vstring.h
+smtp_reuse.o: smtp.h
+smtp_reuse.o: smtp_reuse.c
+smtp_reuse.o: smtp_reuse.h
+smtp_sasl_auth_cache.o: ../../include/argv.h
+smtp_sasl_auth_cache.o: ../../include/attr.h
+smtp_sasl_auth_cache.o: ../../include/base64_code.h
+smtp_sasl_auth_cache.o: ../../include/check_arg.h
+smtp_sasl_auth_cache.o: ../../include/deliver_request.h
+smtp_sasl_auth_cache.o: ../../include/dict.h
+smtp_sasl_auth_cache.o: ../../include/dict_proxy.h
+smtp_sasl_auth_cache.o: ../../include/dns.h
+smtp_sasl_auth_cache.o: ../../include/dsn.h
+smtp_sasl_auth_cache.o: ../../include/dsn_buf.h
+smtp_sasl_auth_cache.o: ../../include/dsn_util.h
+smtp_sasl_auth_cache.o: ../../include/header_body_checks.h
+smtp_sasl_auth_cache.o: ../../include/header_opts.h
+smtp_sasl_auth_cache.o: ../../include/htable.h
+smtp_sasl_auth_cache.o: ../../include/maps.h
+smtp_sasl_auth_cache.o: ../../include/match_list.h
+smtp_sasl_auth_cache.o: ../../include/mime_state.h
+smtp_sasl_auth_cache.o: ../../include/msg.h
+smtp_sasl_auth_cache.o: ../../include/msg_stats.h
+smtp_sasl_auth_cache.o: ../../include/myaddrinfo.h
+smtp_sasl_auth_cache.o: ../../include/myflock.h
+smtp_sasl_auth_cache.o: ../../include/mymalloc.h
+smtp_sasl_auth_cache.o: ../../include/name_code.h
+smtp_sasl_auth_cache.o: ../../include/name_mask.h
+smtp_sasl_auth_cache.o: ../../include/nvtable.h
+smtp_sasl_auth_cache.o: ../../include/recipient_list.h
+smtp_sasl_auth_cache.o: ../../include/resolve_clnt.h
+smtp_sasl_auth_cache.o: ../../include/scache.h
+smtp_sasl_auth_cache.o: ../../include/sock_addr.h
+smtp_sasl_auth_cache.o: ../../include/string_list.h
+smtp_sasl_auth_cache.o: ../../include/stringops.h
+smtp_sasl_auth_cache.o: ../../include/sys_defs.h
+smtp_sasl_auth_cache.o: ../../include/tls.h
+smtp_sasl_auth_cache.o: ../../include/tls_proxy.h
+smtp_sasl_auth_cache.o: ../../include/tok822.h
+smtp_sasl_auth_cache.o: ../../include/vbuf.h
+smtp_sasl_auth_cache.o: ../../include/vstream.h
+smtp_sasl_auth_cache.o: ../../include/vstring.h
+smtp_sasl_auth_cache.o: smtp.h
+smtp_sasl_auth_cache.o: smtp_sasl_auth_cache.c
+smtp_sasl_auth_cache.o: smtp_sasl_auth_cache.h
+smtp_sasl_glue.o: ../../include/argv.h
+smtp_sasl_glue.o: ../../include/attr.h
+smtp_sasl_glue.o: ../../include/check_arg.h
+smtp_sasl_glue.o: ../../include/deliver_request.h
+smtp_sasl_glue.o: ../../include/dict.h
+smtp_sasl_glue.o: ../../include/dns.h
+smtp_sasl_glue.o: ../../include/dsn.h
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+smtp_sasl_glue.o: ../../include/header_body_checks.h
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+smtp_sasl_glue.o: ../../include/htable.h
+smtp_sasl_glue.o: ../../include/mail_addr_find.h
+smtp_sasl_glue.o: ../../include/mail_addr_form.h
+smtp_sasl_glue.o: ../../include/mail_params.h
+smtp_sasl_glue.o: ../../include/maps.h
+smtp_sasl_glue.o: ../../include/match_list.h
+smtp_sasl_glue.o: ../../include/mime_state.h
+smtp_sasl_glue.o: ../../include/msg.h
+smtp_sasl_glue.o: ../../include/msg_stats.h
+smtp_sasl_glue.o: ../../include/myaddrinfo.h
+smtp_sasl_glue.o: ../../include/myflock.h
+smtp_sasl_glue.o: ../../include/mymalloc.h
+smtp_sasl_glue.o: ../../include/name_code.h
+smtp_sasl_glue.o: ../../include/name_mask.h
+smtp_sasl_glue.o: ../../include/nvtable.h
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+smtp_sasl_glue.o: ../../include/scache.h
+smtp_sasl_glue.o: ../../include/smtp_stream.h
+smtp_sasl_glue.o: ../../include/sock_addr.h
+smtp_sasl_glue.o: ../../include/split_at.h
+smtp_sasl_glue.o: ../../include/string_list.h
+smtp_sasl_glue.o: ../../include/stringops.h
+smtp_sasl_glue.o: ../../include/sys_defs.h
+smtp_sasl_glue.o: ../../include/tls.h
+smtp_sasl_glue.o: ../../include/tls_proxy.h
+smtp_sasl_glue.o: ../../include/tok822.h
+smtp_sasl_glue.o: ../../include/vbuf.h
+smtp_sasl_glue.o: ../../include/vstream.h
+smtp_sasl_glue.o: ../../include/vstring.h
+smtp_sasl_glue.o: ../../include/xsasl.h
+smtp_sasl_glue.o: smtp.h
+smtp_sasl_glue.o: smtp_sasl.h
+smtp_sasl_glue.o: smtp_sasl_auth_cache.h
+smtp_sasl_glue.o: smtp_sasl_glue.c
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+smtp_sasl_proto.o: ../../include/attr.h
+smtp_sasl_proto.o: ../../include/check_arg.h
+smtp_sasl_proto.o: ../../include/deliver_request.h
+smtp_sasl_proto.o: ../../include/dict.h
+smtp_sasl_proto.o: ../../include/dns.h
+smtp_sasl_proto.o: ../../include/dsn.h
+smtp_sasl_proto.o: ../../include/dsn_buf.h
+smtp_sasl_proto.o: ../../include/header_body_checks.h
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+smtp_sasl_proto.o: ../../include/htable.h
+smtp_sasl_proto.o: ../../include/mail_params.h
+smtp_sasl_proto.o: ../../include/maps.h
+smtp_sasl_proto.o: ../../include/match_list.h
+smtp_sasl_proto.o: ../../include/mime_state.h
+smtp_sasl_proto.o: ../../include/msg.h
+smtp_sasl_proto.o: ../../include/msg_stats.h
+smtp_sasl_proto.o: ../../include/myaddrinfo.h
+smtp_sasl_proto.o: ../../include/myflock.h
+smtp_sasl_proto.o: ../../include/mymalloc.h
+smtp_sasl_proto.o: ../../include/name_code.h
+smtp_sasl_proto.o: ../../include/name_mask.h
+smtp_sasl_proto.o: ../../include/nvtable.h
+smtp_sasl_proto.o: ../../include/recipient_list.h
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+smtp_sasl_proto.o: ../../include/sock_addr.h
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+smtp_sasl_proto.o: ../../include/sys_defs.h
+smtp_sasl_proto.o: ../../include/tls.h
+smtp_sasl_proto.o: ../../include/tls_proxy.h
+smtp_sasl_proto.o: ../../include/tok822.h
+smtp_sasl_proto.o: ../../include/vbuf.h
+smtp_sasl_proto.o: ../../include/vstream.h
+smtp_sasl_proto.o: ../../include/vstring.h
+smtp_sasl_proto.o: smtp.h
+smtp_sasl_proto.o: smtp_sasl.h
+smtp_sasl_proto.o: smtp_sasl_proto.c
+smtp_session.o: ../../include/argv.h
+smtp_session.o: ../../include/attr.h
+smtp_session.o: ../../include/check_arg.h
+smtp_session.o: ../../include/debug_peer.h
+smtp_session.o: ../../include/deliver_request.h
+smtp_session.o: ../../include/dict.h
+smtp_session.o: ../../include/dns.h
+smtp_session.o: ../../include/dsn.h
+smtp_session.o: ../../include/dsn_buf.h
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+smtp_session.o: ../../include/htable.h
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+smtp_session.o: ../../include/msg_stats.h
+smtp_session.o: ../../include/myaddrinfo.h
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+smtp_session.o: ../../include/name_code.h
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+smtp_session.o: ../../include/tls.h
+smtp_session.o: ../../include/tls_proxy.h
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+smtp_session.o: ../../include/vstream.h
+smtp_session.o: ../../include/vstring.h
+smtp_session.o: smtp.h
+smtp_session.o: smtp_sasl.h
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+smtp_state.o: ../../include/check_arg.h
+smtp_state.o: ../../include/deliver_request.h
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+smtp_state.o: ../../include/myaddrinfo.h
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+smtp_state.o: smtp.h
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+smtp_tls_policy.o: ../../include/check_arg.h
+smtp_tls_policy.o: ../../include/ctable.h
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+smtp_tls_policy.o: ../../include/dns.h
+smtp_tls_policy.o: ../../include/dsn.h
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+smtp_unalias.o: ../../include/match_list.h
+smtp_unalias.o: ../../include/mime_state.h
+smtp_unalias.o: ../../include/msg.h
+smtp_unalias.o: ../../include/msg_stats.h
+smtp_unalias.o: ../../include/myaddrinfo.h
+smtp_unalias.o: ../../include/myflock.h
+smtp_unalias.o: ../../include/mymalloc.h
+smtp_unalias.o: ../../include/name_code.h
+smtp_unalias.o: ../../include/name_mask.h
+smtp_unalias.o: ../../include/nvtable.h
+smtp_unalias.o: ../../include/recipient_list.h
+smtp_unalias.o: ../../include/resolve_clnt.h
+smtp_unalias.o: ../../include/scache.h
+smtp_unalias.o: ../../include/sock_addr.h
+smtp_unalias.o: ../../include/string_list.h
+smtp_unalias.o: ../../include/sys_defs.h
+smtp_unalias.o: ../../include/tls.h
+smtp_unalias.o: ../../include/tls_proxy.h
+smtp_unalias.o: ../../include/tok822.h
+smtp_unalias.o: ../../include/vbuf.h
+smtp_unalias.o: ../../include/vstream.h
+smtp_unalias.o: ../../include/vstring.h
+smtp_unalias.o: smtp.h
+smtp_unalias.o: smtp_unalias.c
diff --git a/src/smtp/lmtp_params.c b/src/smtp/lmtp_params.c
new file mode 100644
index 0000000..973cb5d
--- /dev/null
+++ b/src/smtp/lmtp_params.c
@@ -0,0 +1,130 @@
+    static const CONFIG_STR_TABLE lmtp_str_table[] = {
+	VAR_NOTIFY_CLASSES, DEF_NOTIFY_CLASSES, &var_notify_classes, 0, 0,
+	VAR_LMTP_FALLBACK, DEF_LMTP_FALLBACK, &var_fallback_relay, 0, 0,
+	VAR_BESTMX_TRANSP, DEF_BESTMX_TRANSP, &var_bestmx_transp, 0, 0,
+	VAR_ERROR_RCPT, DEF_ERROR_RCPT, &var_error_rcpt, 1, 0,
+	VAR_LMTP_SASL_PASSWD, DEF_LMTP_SASL_PASSWD, &var_smtp_sasl_passwd, 0, 0,
+	VAR_LMTP_SASL_OPTS, DEF_LMTP_SASL_OPTS, &var_smtp_sasl_opts, 0, 0,
+	VAR_LMTP_SASL_PATH, DEF_LMTP_SASL_PATH, &var_smtp_sasl_path, 0, 0,
+#ifdef USE_TLS
+	VAR_LMTP_SASL_TLS_OPTS, DEF_LMTP_SASL_TLS_OPTS, &var_smtp_sasl_tls_opts, 0, 0,
+	VAR_LMTP_SASL_TLSV_OPTS, DEF_LMTP_SASL_TLSV_OPTS, &var_smtp_sasl_tlsv_opts, 0, 0,
+	VAR_LMTP_TLS_CHAIN_FILES, DEF_LMTP_TLS_CHAIN_FILES, &var_smtp_tls_chain_files, 0, 0,
+	VAR_LMTP_TLS_CERT_FILE, DEF_LMTP_TLS_CERT_FILE, &var_smtp_tls_cert_file, 0, 0,
+	VAR_LMTP_TLS_KEY_FILE, DEF_LMTP_TLS_KEY_FILE, &var_smtp_tls_key_file, 0, 0,
+	VAR_LMTP_TLS_DCERT_FILE, DEF_LMTP_TLS_DCERT_FILE, &var_smtp_tls_dcert_file, 0, 0,
+	VAR_LMTP_TLS_DKEY_FILE, DEF_LMTP_TLS_DKEY_FILE, &var_smtp_tls_dkey_file, 0, 0,
+	VAR_LMTP_TLS_CA_FILE, DEF_LMTP_TLS_CA_FILE, &var_smtp_tls_CAfile, 0, 0,
+	VAR_LMTP_TLS_CA_PATH, DEF_LMTP_TLS_CA_PATH, &var_smtp_tls_CApath, 0, 0,
+	VAR_LMTP_TLS_MAND_CIPH, DEF_LMTP_TLS_MAND_CIPH, &var_smtp_tls_mand_ciph, 1, 0,
+	VAR_LMTP_TLS_EXCL_CIPH, DEF_LMTP_TLS_EXCL_CIPH, &var_smtp_tls_excl_ciph, 0, 0,
+	VAR_LMTP_TLS_MAND_EXCL, DEF_LMTP_TLS_MAND_EXCL, &var_smtp_tls_mand_excl, 0, 0,
+	VAR_LMTP_TLS_MAND_PROTO, DEF_LMTP_TLS_MAND_PROTO, &var_smtp_tls_mand_proto, 0, 0,
+	VAR_LMTP_TLS_VFY_CMATCH, DEF_LMTP_TLS_VFY_CMATCH, &var_smtp_tls_vfy_cmatch, 1, 0,
+	VAR_LMTP_TLS_SEC_CMATCH, DEF_LMTP_TLS_SEC_CMATCH, &var_smtp_tls_sec_cmatch, 1, 0,
+	VAR_LMTP_TLS_FPT_CMATCH, DEF_LMTP_TLS_FPT_CMATCH, &var_smtp_tls_fpt_cmatch, 0, 0,
+	VAR_LMTP_TLS_FPT_DGST, DEF_LMTP_TLS_FPT_DGST, &var_smtp_tls_fpt_dgst, 1, 0,
+	VAR_LMTP_TLS_TAFILE, DEF_LMTP_TLS_TAFILE, &var_smtp_tls_tafile, 0, 0,
+	VAR_LMTP_TLS_PROTO, DEF_LMTP_TLS_PROTO, &var_smtp_tls_proto, 0, 0,
+	VAR_LMTP_TLS_CIPH, DEF_LMTP_TLS_CIPH, &var_smtp_tls_ciph, 1, 0,
+	VAR_LMTP_TLS_ECCERT_FILE, DEF_LMTP_TLS_ECCERT_FILE, &var_smtp_tls_eccert_file, 0, 0,
+	VAR_LMTP_TLS_ECKEY_FILE, DEF_LMTP_TLS_ECKEY_FILE, &var_smtp_tls_eckey_file, 0, 0,
+	VAR_LMTP_TLS_LOGLEVEL, DEF_LMTP_TLS_LOGLEVEL, &var_smtp_tls_loglevel, 0, 0,
+	VAR_LMTP_TLS_SNI, DEF_LMTP_TLS_SNI, &var_smtp_tls_sni, 0, 0,
+#endif
+	VAR_LMTP_SASL_MECHS, DEF_LMTP_SASL_MECHS, &var_smtp_sasl_mechs, 0, 0,
+	VAR_LMTP_SASL_TYPE, DEF_LMTP_SASL_TYPE, &var_smtp_sasl_type, 1, 0,
+	VAR_LMTP_BIND_ADDR, DEF_LMTP_BIND_ADDR, &var_smtp_bind_addr, 0, 0,
+	VAR_LMTP_BIND_ADDR6, DEF_LMTP_BIND_ADDR6, &var_smtp_bind_addr6, 0, 0,
+	VAR_LMTP_VRFY_TGT, DEF_LMTP_VRFY_TGT, &var_smtp_vrfy_tgt, 1, 0,
+	VAR_LMTP_HELO_NAME, DEF_LMTP_HELO_NAME, &var_smtp_helo_name, 1, 0,
+	VAR_LMTP_HOST_LOOKUP, DEF_LMTP_HOST_LOOKUP, &var_smtp_host_lookup, 1, 0,
+	VAR_LMTP_DNS_SUPPORT, DEF_LMTP_DNS_SUPPORT, &var_smtp_dns_support, 0, 0,
+	VAR_LMTP_CACHE_DEST, DEF_LMTP_CACHE_DEST, &var_smtp_cache_dest, 0, 0,
+	VAR_SCACHE_SERVICE, DEF_SCACHE_SERVICE, &var_scache_service, 1, 0,
+	VAR_LMTP_EHLO_DIS_WORDS, DEF_LMTP_EHLO_DIS_WORDS, &var_smtp_ehlo_dis_words, 0, 0,
+	VAR_LMTP_EHLO_DIS_MAPS, DEF_LMTP_EHLO_DIS_MAPS, &var_smtp_ehlo_dis_maps, 0, 0,
+	VAR_LMTP_TLS_PER_SITE, DEF_LMTP_TLS_PER_SITE, &var_smtp_tls_per_site, 0, 0,
+	VAR_LMTP_TLS_LEVEL, DEF_LMTP_TLS_LEVEL, &var_smtp_tls_level, 0, 0,
+	VAR_LMTP_TLS_POLICY, DEF_LMTP_TLS_POLICY, &var_smtp_tls_policy, 0, 0,
+	VAR_PROP_EXTENSION, DEF_PROP_EXTENSION, &var_prop_extension, 0, 0,
+	VAR_LMTP_GENERIC_MAPS, DEF_LMTP_GENERIC_MAPS, &var_smtp_generic_maps, 0, 0,
+	VAR_LMTP_TCP_PORT, DEF_LMTP_TCP_PORT, &var_smtp_tcp_port, 0, 0,
+	VAR_LMTP_PIX_BUG_WORDS, DEF_LMTP_PIX_BUG_WORDS, &var_smtp_pix_bug_words, 0, 0,
+	VAR_LMTP_PIX_BUG_MAPS, DEF_LMTP_PIX_BUG_MAPS, &var_smtp_pix_bug_maps, 0, 0,
+	VAR_LMTP_SASL_AUTH_CACHE_NAME, DEF_LMTP_SASL_AUTH_CACHE_NAME, &var_smtp_sasl_auth_cache_name, 0, 0,
+	VAR_CYRUS_CONF_PATH, DEF_CYRUS_CONF_PATH, &var_cyrus_conf_path, 0, 0,
+	VAR_LMTP_HEAD_CHKS, DEF_LMTP_HEAD_CHKS, &var_smtp_head_chks, 0, 0,
+	VAR_LMTP_MIME_CHKS, DEF_LMTP_MIME_CHKS, &var_smtp_mime_chks, 0, 0,
+	VAR_LMTP_NEST_CHKS, DEF_LMTP_NEST_CHKS, &var_smtp_nest_chks, 0, 0,
+	VAR_LMTP_BODY_CHKS, DEF_LMTP_BODY_CHKS, &var_smtp_body_chks, 0, 0,
+	VAR_LMTP_RESP_FILTER, DEF_LMTP_RESP_FILTER, &var_smtp_resp_filter, 0, 0,
+	VAR_LMTP_ADDR_PREF, DEF_LMTP_ADDR_PREF, &var_smtp_addr_pref, 1, 0,
+	VAR_LMTP_DNS_RES_OPT, DEF_LMTP_DNS_RES_OPT, &var_smtp_dns_res_opt, 0, 0,
+	VAR_LMTP_DSN_FILTER, DEF_LMTP_DSN_FILTER, &var_smtp_dsn_filter, 0, 0,
+	VAR_LMTP_DNS_RE_FILTER, DEF_LMTP_DNS_RE_FILTER, &var_smtp_dns_re_filter, 0, 0,
+	VAR_TLSPROXY_SERVICE, DEF_TLSPROXY_SERVICE, &var_tlsproxy_service, 1, 0,
+	0,
+    };
+    static const CONFIG_TIME_TABLE lmtp_time_table[] = {
+	VAR_LMTP_CONN_TMOUT, DEF_LMTP_CONN_TMOUT, &var_smtp_conn_tmout, 0, 0,
+	VAR_LMTP_HELO_TMOUT, DEF_LMTP_HELO_TMOUT, &var_smtp_helo_tmout, 1, 0,
+	VAR_LMTP_XFWD_TMOUT, DEF_LMTP_XFWD_TMOUT, &var_smtp_xfwd_tmout, 1, 0,
+	VAR_LMTP_MAIL_TMOUT, DEF_LMTP_MAIL_TMOUT, &var_smtp_mail_tmout, 1, 0,
+	VAR_LMTP_RCPT_TMOUT, DEF_LMTP_RCPT_TMOUT, &var_smtp_rcpt_tmout, 1, 0,
+	VAR_LMTP_DATA0_TMOUT, DEF_LMTP_DATA0_TMOUT, &var_smtp_data0_tmout, 1, 0,
+	VAR_LMTP_DATA1_TMOUT, DEF_LMTP_DATA1_TMOUT, &var_smtp_data1_tmout, 1, 0,
+	VAR_LMTP_DATA2_TMOUT, DEF_LMTP_DATA2_TMOUT, &var_smtp_data2_tmout, 1, 0,
+	VAR_LMTP_RSET_TMOUT, DEF_LMTP_RSET_TMOUT, &var_smtp_rset_tmout, 1, 0,
+	VAR_LMTP_QUIT_TMOUT, DEF_LMTP_QUIT_TMOUT, &var_smtp_quit_tmout, 1, 0,
+	VAR_LMTP_PIX_THRESH, DEF_LMTP_PIX_THRESH, &var_smtp_pix_thresh, 0, 0,
+	VAR_LMTP_PIX_DELAY, DEF_LMTP_PIX_DELAY, &var_smtp_pix_delay, 1, 0,
+	VAR_QUEUE_RUN_DELAY, DEF_QUEUE_RUN_DELAY, &var_queue_run_delay, 1, 0,
+	VAR_MIN_BACKOFF_TIME, DEF_MIN_BACKOFF_TIME, &var_min_backoff_time, 1, 0,
+	VAR_LMTP_CACHE_CONNT, DEF_LMTP_CACHE_CONNT, &var_smtp_cache_conn, 1, 0,
+	VAR_LMTP_REUSE_TIME, DEF_LMTP_REUSE_TIME, &var_smtp_reuse_time, 1, 0,
+#ifdef USE_TLS
+	VAR_LMTP_STARTTLS_TMOUT, DEF_LMTP_STARTTLS_TMOUT, &var_smtp_starttls_tmout, 1, 0,
+#endif
+	VAR_SCACHE_PROTO_TMOUT, DEF_SCACHE_PROTO_TMOUT, &var_scache_proto_tmout, 1, 0,
+	VAR_LMTP_SASL_AUTH_CACHE_TIME, DEF_LMTP_SASL_AUTH_CACHE_TIME, &var_smtp_sasl_auth_cache_time, 0, 0,
+	0,
+    };
+    static const CONFIG_INT_TABLE lmtp_int_table[] = {
+	VAR_LMTP_LINE_LIMIT, DEF_LMTP_LINE_LIMIT, &var_smtp_line_limit, 0, 0,
+	VAR_LMTP_MXADDR_LIMIT, DEF_LMTP_MXADDR_LIMIT, &var_smtp_mxaddr_limit, 0, 0,
+	VAR_LMTP_MXSESS_LIMIT, DEF_LMTP_MXSESS_LIMIT, &var_smtp_mxsess_limit, 0, 0,
+	VAR_LMTP_REUSE_COUNT, DEF_LMTP_REUSE_COUNT, &var_smtp_reuse_count, 0, 0,
+#ifdef USE_TLS
+	VAR_LMTP_TLS_SCERT_VD, DEF_LMTP_TLS_SCERT_VD, &var_smtp_tls_scert_vd, 0, 0,
+#endif
+	0,
+    };
+    static const CONFIG_BOOL_TABLE lmtp_bool_table[] = {
+	VAR_LMTP_SKIP_5XX, DEF_LMTP_SKIP_5XX, &var_smtp_skip_5xx_greeting,
+	VAR_LMTP_SKIP_QUIT_RESP, DEF_LMTP_SKIP_QUIT_RESP, &var_skip_quit_resp,
+	VAR_LMTP_SASL_ENABLE, DEF_LMTP_SASL_ENABLE, &var_smtp_sasl_enable,
+	VAR_LMTP_RAND_ADDR, DEF_LMTP_RAND_ADDR, &var_smtp_rand_addr,
+	VAR_LMTP_QUOTE_821_ENV, DEF_LMTP_QUOTE_821_ENV, &var_smtp_quote_821_env,
+	VAR_LMTP_DEFER_MXADDR, DEF_LMTP_DEFER_MXADDR, &var_smtp_defer_mxaddr,
+	VAR_LMTP_SEND_XFORWARD, DEF_LMTP_SEND_XFORWARD, &var_smtp_send_xforward,
+	VAR_LMTP_CACHE_DEMAND, DEF_LMTP_CACHE_DEMAND, &var_smtp_cache_demand,
+	VAR_LMTP_USE_TLS, DEF_LMTP_USE_TLS, &var_smtp_use_tls,
+	VAR_LMTP_ENFORCE_TLS, DEF_LMTP_ENFORCE_TLS, &var_smtp_enforce_tls,
+	VAR_LMTP_TLS_CONN_REUSE, DEF_LMTP_TLS_CONN_REUSE, &var_smtp_tls_conn_reuse,
+#ifdef USE_TLS
+	VAR_LMTP_TLS_ENFORCE_PN, DEF_LMTP_TLS_ENFORCE_PN, &var_smtp_tls_enforce_peername,
+	VAR_LMTP_TLS_NOTEOFFER, DEF_LMTP_TLS_NOTEOFFER, &var_smtp_tls_note_starttls_offer,
+	VAR_LMTP_TLS_BLK_EARLY_MAIL_REPLY, DEF_LMTP_TLS_BLK_EARLY_MAIL_REPLY, &var_smtp_tls_blk_early_mail_reply,
+	VAR_LMTP_TLS_FORCE_TLSA, DEF_LMTP_TLS_FORCE_TLSA, &var_smtp_tls_force_tlsa,
+#endif
+	VAR_LMTP_TLS_WRAPPER, DEF_LMTP_TLS_WRAPPER, &var_smtp_tls_wrappermode,
+	VAR_LMTP_SENDER_AUTH, DEF_LMTP_SENDER_AUTH, &var_smtp_sender_auth,
+	VAR_LMTP_CNAME_OVERR, DEF_LMTP_CNAME_OVERR, &var_smtp_cname_overr,
+	VAR_LMTP_SASL_AUTH_SOFT_BOUNCE, DEF_LMTP_SASL_AUTH_SOFT_BOUNCE, &var_smtp_sasl_auth_soft_bounce,
+	VAR_LMTP_ASSUME_FINAL, DEF_LMTP_ASSUME_FINAL, &var_lmtp_assume_final,
+	VAR_LMTP_REC_DEADLINE, DEF_LMTP_REC_DEADLINE, &var_smtp_rec_deadline,
+	VAR_LMTP_DUMMY_MAIL_AUTH, DEF_LMTP_DUMMY_MAIL_AUTH, &var_smtp_dummy_mail_auth,
+	VAR_LMTP_BALANCE_INET_PROTO, DEF_LMTP_BALANCE_INET_PROTO, &var_smtp_balance_inet_proto,
+	0,
+    };
diff --git a/src/smtp/smtp-only b/src/smtp/smtp-only
new file mode 100644
index 0000000..ee9288d
--- /dev/null
+++ b/src/smtp/smtp-only
@@ -0,0 +1,4 @@
+_ALWAYS_EHLO
+_NEVER_EHLO
+_IGN_MX_LOOKUP_ERR
+_INSECURE_MX_POLICY
diff --git a/src/smtp/smtp.c b/src/smtp/smtp.c
new file mode 100644
index 0000000..9a28cc2
--- /dev/null
+++ b/src/smtp/smtp.c
@@ -0,0 +1,1605 @@
+/*++
+/* NAME
+/*	smtp 8
+/* SUMMARY
+/*	Postfix SMTP+LMTP client
+/* SYNOPSIS
+/*	\fBsmtp\fR [generic Postfix daemon options] [flags=DORX]
+/* DESCRIPTION
+/*	The Postfix SMTP+LMTP client implements the SMTP and LMTP mail
+/*	delivery protocols. It processes message delivery requests from
+/*	the queue manager. Each request specifies a queue file, a sender
+/*	address, a domain or host to deliver to, and recipient information.
+/*	This program expects to be run from the \fBmaster\fR(8) process
+/*	manager.
+/*
+/*	The SMTP+LMTP client updates the queue file and marks recipients
+/*	as finished, or it informs the queue manager that delivery should
+/*	be tried again at a later time. Delivery status reports are sent
+/*	to the \fBbounce\fR(8), \fBdefer\fR(8) or \fBtrace\fR(8) daemon as
+/*	appropriate.
+/*
+/*	The SMTP+LMTP client looks up a list of mail exchanger addresses for
+/*	the destination host, sorts the list by preference, and connects
+/*	to each listed address until it finds a server that responds.
+/*
+/*	When a server is not reachable, or when mail delivery fails due
+/*	to a recoverable error condition, the SMTP+LMTP client will try to
+/*	deliver the mail to an alternate host.
+/*
+/*	After a successful mail transaction, a connection may be saved
+/*	to the \fBscache\fR(8) connection cache server, so that it
+/*	may be used by any SMTP+LMTP client for a subsequent transaction.
+/*
+/*	By default, connection caching is enabled temporarily for
+/*	destinations that have a high volume of mail in the active
+/*	queue. Connection caching can be enabled permanently for
+/*	specific destinations.
+/* SMTP DESTINATION SYNTAX
+/* .ad
+/* .fi
+/*	The Postfix SMTP+LMTP client supports multiple destinations
+/*	separated by comma or whitespace (Postfix 3.5 and later).
+/*	SMTP destinations have the following form:
+/* .IP \fIdomainname\fR
+/* .IP \fIdomainname\fR:\fIport\fR
+/*	Look up the mail exchangers for the specified domain, and
+/*	connect to the specified port (default: \fBsmtp\fR).
+/* .IP [\fIhostname\fR]
+/* .IP [\fIhostname\fR]:\fIport\fR
+/*	Look up the address(es) of the specified host, and connect to
+/*	the specified port (default: \fBsmtp\fR).
+/* .IP [\fIaddress\fR]
+/* .IP [\fIaddress\fR]:\fIport\fR
+/*	Connect to the host at the specified address, and connect
+/*	to the specified port (default: \fBsmtp\fR). An IPv6 address
+/*	must be formatted as [\fBipv6\fR:\fIaddress\fR].
+/* LMTP DESTINATION SYNTAX
+/* .ad
+/* .fi
+/*	The Postfix SMTP+LMTP client supports multiple destinations
+/*	separated by comma or whitespace (Postfix 3.5 and later).
+/*	LMTP destinations have the following form:
+/* .IP \fBunix\fR:\fIpathname\fR
+/*	Connect to the local UNIX-domain server that is bound to the specified
+/*	\fIpathname\fR. If the process runs chrooted, an absolute pathname
+/*	is interpreted relative to the Postfix queue directory.
+/* .IP \fBinet\fR:\fIhostname\fR
+/* .IP \fBinet\fR:\fIhostname\fR:\fIport\fR
+/* .IP \fBinet\fR:[\fIaddress\fR]
+/* .IP \fBinet\fR:[\fIaddress\fR]:\fIport\fR
+/*	Connect to the specified TCP port on the specified local or
+/*	remote host. If no port is specified, connect to the port defined as
+/*	\fBlmtp\fR in \fBservices\fR(4).
+/*	If no such service is found, the \fBlmtp_tcp_port\fR configuration
+/*	parameter (default value of 24) will be used.
+/*	An IPv6 address must be formatted as [\fBipv6\fR:\fIaddress\fR].
+/* SINGLE-RECIPIENT DELIVERY
+/* .ad
+/* .fi
+/*	By default, the Postfix SMTP+LMTP client delivers mail to
+/*	multiple recipients per delivery request. This is undesirable
+/*	when prepending a \fBDelivered-to:\fR or \fBX-Original-To:\fR
+/*	message header. To prevent Postfix from sending multiple
+/*	recipients per delivery request, specify
+/* .sp
+/* .nf
+/*	    \fItransport\fB_destination_recipient_limit = 1\fR
+/* .fi
+/*
+/*	in the Postfix \fBmain.cf\fR file, where \fItransport\fR
+/*	is the name in the first column of the Postfix \fBmaster.cf\fR
+/*	entry for this mail delivery service.
+/* COMMAND ATTRIBUTE SYNTAX
+/* .ad
+/* .fi
+/* .IP "\fBflags=DORX\fR (optional)"
+/*	Optional message processing flags.
+/* .RS
+/* .IP \fBD\fR
+/*	Prepend a "\fBDelivered-To: \fIrecipient\fR" message header
+/*	with the envelope recipient address. Note: for this to work,
+/*	the \fItransport\fB_destination_recipient_limit\fR must be
+/*	1 (see SINGLE-RECIPIENT DELIVERY above for details).
+/* .sp
+/*	The \fBD\fR flag also enforces loop detection: if a message
+/*	already contains a \fBDelivered-To:\fR header with the same
+/*	recipient address, then the message is returned as
+/*	undeliverable. The address comparison is case insensitive.
+/* .sp
+/*	This feature is available as of Postfix 3.5.
+/* .IP \fBO\fR
+/*	Prepend an "\fBX-Original-To: \fIrecipient\fR" message
+/*	header with the recipient address as given to Postfix. Note:
+/*	for this to work, the
+/*	\fItransport\fB_destination_recipient_limit\fR must be 1
+/*	(see SINGLE-RECIPIENT DELIVERY above for details).
+/* .sp
+/*	This feature is available as of Postfix 3.5.
+/* .IP \fBR\fR
+/*	Prepend a "\fBReturn-Path: <\fIsender\fB>\fR" message header
+/*	with the envelope sender address.
+/* .sp
+/*	This feature is available as of Postfix 3.5.
+/* .IP \fBX\fR
+/*	Indicates that the delivery is final. This flag affects
+/*	the status reported in "success" DSN (delivery status
+/*	notification) messages, and changes it from "relayed" into
+/*	"delivered".
+/* .sp
+/*	This feature is available as of Postfix 3.5.
+/* .RE
+/* SECURITY
+/*	The SMTP+LMTP client is moderately security-sensitive. It
+/*	talks to SMTP or LMTP servers and to DNS servers on the
+/*	network. The SMTP+LMTP client can be run chrooted at fixed
+/*	low privilege.
+/* STANDARDS
+/*	RFC 821 (SMTP protocol)
+/*	RFC 822 (ARPA Internet Text Messages)
+/*	RFC 1651 (SMTP service extensions)
+/*	RFC 1652 (8bit-MIME transport)
+/*	RFC 1870 (Message Size Declaration)
+/*	RFC 2033 (LMTP protocol)
+/*	RFC 2034 (SMTP Enhanced Error Codes)
+/*	RFC 2045 (MIME: Format of Internet Message Bodies)
+/*	RFC 2046 (MIME: Media Types)
+/*	RFC 2554 (AUTH command)
+/*	RFC 2821 (SMTP protocol)
+/*	RFC 2920 (SMTP Pipelining)
+/*	RFC 3207 (STARTTLS command)
+/*	RFC 3461 (SMTP DSN Extension)
+/*	RFC 3463 (Enhanced Status Codes)
+/*	RFC 4954 (AUTH command)
+/*	RFC 5321 (SMTP protocol)
+/*	RFC 6531 (Internationalized SMTP)
+/*	RFC 6533 (Internationalized Delivery Status Notifications)
+/*	RFC 7672 (SMTP security via opportunistic DANE TLS)
+/* DIAGNOSTICS
+/*	Problems and transactions are logged to \fBsyslogd\fR(8)
+/*	or \fBpostlogd\fR(8).
+/*	Corrupted message files are marked so that the queue manager can
+/*	move them to the \fBcorrupt\fR queue for further inspection.
+/*
+/*	Depending on the setting of the \fBnotify_classes\fR parameter,
+/*	the postmaster is notified of bounces, protocol problems, and of
+/*	other trouble.
+/* BUGS
+/*	SMTP and LMTP connection reuse for TLS (without closing the
+/*	SMTP or LMTP connection) is not supported before Postfix 3.4.
+/*
+/*	SMTP and LMTP connection reuse assumes that SASL credentials
+/*	are valid for all destinations that map onto the same IP
+/*	address and TCP port.
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/*	Before Postfix version 2.3, the LMTP client is a separate
+/*	program that implements only a subset of the functionality
+/*	available with SMTP: there is no support for TLS, and
+/*	connections are cached in-process, making it ineffective
+/*	when the client is used for multiple domains.
+/*
+/*	Most smtp_\fIxxx\fR configuration parameters have an
+/*	lmtp_\fIxxx\fR "mirror" parameter for the equivalent LMTP
+/*	feature. This document describes only those LMTP-related
+/*	parameters that aren't simply "mirror" parameters.
+/*
+/*	Changes to \fBmain.cf\fR are picked up automatically, as \fBsmtp\fR(8)
+/*	processes run for only a limited amount of time. Use the command
+/*	"\fBpostfix reload\fR" to speed up a change.
+/*
+/*	The text below provides only a parameter summary. See
+/*	\fBpostconf\fR(5) for more details including examples.
+/* COMPATIBILITY CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBignore_mx_lookup_error (no)\fR"
+/*	Ignore DNS MX lookups that produce no response.
+/* .IP "\fBsmtp_always_send_ehlo (yes)\fR"
+/*	Always send EHLO at the start of an SMTP session.
+/* .IP "\fBsmtp_never_send_ehlo (no)\fR"
+/*	Never send EHLO at the start of an SMTP session.
+/* .IP "\fBsmtp_defer_if_no_mx_address_found (no)\fR"
+/*	Defer mail delivery when no MX record resolves to an IP address.
+/* .IP "\fBsmtp_line_length_limit (998)\fR"
+/*	The maximal length of message header and body lines that Postfix
+/*	will send via SMTP.
+/* .IP "\fBsmtp_pix_workaround_delay_time (10s)\fR"
+/*	How long the Postfix SMTP client pauses before sending
+/*	".<CR><LF>" in order to work around the PIX firewall
+/*	"<CR><LF>.<CR><LF>" bug.
+/* .IP "\fBsmtp_pix_workaround_threshold_time (500s)\fR"
+/*	How long a message must be queued before the Postfix SMTP client
+/*	turns on the PIX firewall "<CR><LF>.<CR><LF>"
+/*	bug workaround for delivery through firewalls with "smtp fixup"
+/*	mode turned on.
+/* .IP "\fBsmtp_pix_workarounds (disable_esmtp, delay_dotcrlf)\fR"
+/*	A list that specifies zero or more workarounds for CISCO PIX
+/*	firewall bugs.
+/* .IP "\fBsmtp_pix_workaround_maps (empty)\fR"
+/*	Lookup tables, indexed by the remote SMTP server address, with
+/*	per-destination workarounds for CISCO PIX firewall bugs.
+/* .IP "\fBsmtp_quote_rfc821_envelope (yes)\fR"
+/*	Quote addresses in Postfix SMTP client MAIL FROM and RCPT TO commands
+/*	as required
+/*	by RFC 5321.
+/* .IP "\fBsmtp_reply_filter (empty)\fR"
+/*	A mechanism to transform replies from remote SMTP servers one
+/*	line at a time.
+/* .IP "\fBsmtp_skip_5xx_greeting (yes)\fR"
+/*	Skip remote SMTP servers that greet with a 5XX status code.
+/* .IP "\fBsmtp_skip_quit_response (yes)\fR"
+/*	Do not wait for the response to the SMTP QUIT command.
+/* .PP
+/*	Available in Postfix version 2.0 and earlier:
+/* .IP "\fBsmtp_skip_4xx_greeting (yes)\fR"
+/*	Skip SMTP servers that greet with a 4XX status code (go away, try
+/*	again later).
+/* .PP
+/*	Available in Postfix version 2.2 and later:
+/* .IP "\fBsmtp_discard_ehlo_keyword_address_maps (empty)\fR"
+/*	Lookup tables, indexed by the remote SMTP server address, with
+/*	case insensitive lists of EHLO keywords (pipelining, starttls, auth,
+/*	etc.) that the Postfix SMTP client will ignore in the EHLO response from a
+/*	remote SMTP server.
+/* .IP "\fBsmtp_discard_ehlo_keywords (empty)\fR"
+/*	A case insensitive list of EHLO keywords (pipelining, starttls,
+/*	auth, etc.) that the Postfix SMTP client will ignore in the EHLO
+/*	response from a remote SMTP server.
+/* .IP "\fBsmtp_generic_maps (empty)\fR"
+/*	Optional lookup tables that perform address rewriting in the
+/*	Postfix SMTP client, typically to transform a locally valid address into
+/*	a globally valid address when sending mail across the Internet.
+/* .PP
+/*	Available in Postfix version 2.2.9 and later:
+/* .IP "\fBsmtp_cname_overrides_servername (version dependent)\fR"
+/*	When the remote SMTP servername is a DNS CNAME, replace the
+/*	servername with the result from CNAME expansion for the purpose of
+/*	logging, SASL password lookup, TLS
+/*	policy decisions, or TLS certificate verification.
+/* .PP
+/*	Available in Postfix version 2.3 and later:
+/* .IP "\fBlmtp_discard_lhlo_keyword_address_maps (empty)\fR"
+/*	Lookup tables, indexed by the remote LMTP server address, with
+/*	case insensitive lists of LHLO keywords (pipelining, starttls,
+/*	auth, etc.) that the Postfix LMTP client will ignore in the LHLO
+/*	response
+/*	from a remote LMTP server.
+/* .IP "\fBlmtp_discard_lhlo_keywords (empty)\fR"
+/*	A case insensitive list of LHLO keywords (pipelining, starttls,
+/*	auth, etc.) that the Postfix LMTP client will ignore in the LHLO
+/*	response
+/*	from a remote LMTP server.
+/* .PP
+/*	Available in Postfix version 2.4.4 and later:
+/* .IP "\fBsend_cyrus_sasl_authzid (no)\fR"
+/*	When authenticating to a remote SMTP or LMTP server with the
+/*	default setting "no", send no SASL authoriZation ID (authzid); send
+/*	only the SASL authentiCation ID (authcid) plus the authcid's password.
+/* .PP
+/*	Available in Postfix version 2.5 and later:
+/* .IP "\fBsmtp_header_checks (empty)\fR"
+/*	Restricted \fBheader_checks\fR(5) tables for the Postfix SMTP client.
+/* .IP "\fBsmtp_mime_header_checks (empty)\fR"
+/*	Restricted \fBmime_header_checks\fR(5) tables for the Postfix SMTP
+/*	client.
+/* .IP "\fBsmtp_nested_header_checks (empty)\fR"
+/*	Restricted \fBnested_header_checks\fR(5) tables for the Postfix SMTP
+/*	client.
+/* .IP "\fBsmtp_body_checks (empty)\fR"
+/*	Restricted \fBbody_checks\fR(5) tables for the Postfix SMTP client.
+/* .PP
+/*	Available in Postfix version 2.6 and later:
+/* .IP "\fBtcp_windowsize (0)\fR"
+/*	An optional workaround for routers that break TCP window scaling.
+/* .PP
+/*	Available in Postfix version 2.8 and later:
+/* .IP "\fBsmtp_dns_resolver_options (empty)\fR"
+/*	DNS Resolver options for the Postfix SMTP client.
+/* .PP
+/*	Available in Postfix version 2.9 and later:
+/* .IP "\fBsmtp_per_record_deadline (no)\fR"
+/*	Change the behavior of the smtp_*_timeout time limits, from a
+/*	time limit per read or write system call, to a time limit to send
+/*	or receive a complete record (an SMTP command line, SMTP response
+/*	line, SMTP message content line, or TLS protocol message).
+/* .IP "\fBsmtp_send_dummy_mail_auth (no)\fR"
+/*	Whether or not to append the "AUTH=<>" option to the MAIL
+/*	FROM command in SASL-authenticated SMTP sessions.
+/* .PP
+/*	Available in Postfix version 2.11 and later:
+/* .IP "\fBsmtp_dns_support_level (empty)\fR"
+/*	Level of DNS support in the Postfix SMTP client.
+/* .PP
+/*	Available in Postfix version 3.0 and later:
+/* .IP "\fBsmtp_delivery_status_filter ($default_delivery_status_filter)\fR"
+/*	Optional filter for the \fBsmtp\fR(8) delivery agent to change the
+/*	delivery status code or explanatory text of successful or unsuccessful
+/*	deliveries.
+/* .IP "\fBsmtp_dns_reply_filter (empty)\fR"
+/*	Optional filter for Postfix SMTP client DNS lookup results.
+/* .PP
+/*	Available in Postfix version 3.3 and later:
+/* .IP "\fBsmtp_balance_inet_protocols (yes)\fR"
+/*	When a remote destination resolves to a combination of IPv4 and
+/*	IPv6 addresses, ensure that the Postfix SMTP client can try both
+/*	address types before it runs into the smtp_mx_address_limit.
+/* .PP
+/*	Available in Postfix 3.5 and later:
+/* .IP "\fBinfo_log_address_format (external)\fR"
+/*	The email address form that will be used in non-debug logging
+/*	(info, warning, etc.).
+/* .PP
+/*	Available in Postfix 3.5.9 and later:
+/* .IP "\fBdnssec_probe (ns:.)\fR"
+/*	The DNS query type (default: "ns") and DNS query name (default:
+/*	".") that Postfix may use to determine whether DNSSEC validation
+/*	is available.
+/* MIME PROCESSING CONTROLS
+/* .ad
+/* .fi
+/*	Available in Postfix version 2.0 and later:
+/* .IP "\fBdisable_mime_output_conversion (no)\fR"
+/*	Disable the conversion of 8BITMIME format to 7BIT format.
+/* .IP "\fBmime_boundary_length_limit (2048)\fR"
+/*	The maximal length of MIME multipart boundary strings.
+/* .IP "\fBmime_nesting_limit (100)\fR"
+/*	The maximal recursion level that the MIME processor will handle.
+/* EXTERNAL CONTENT INSPECTION CONTROLS
+/* .ad
+/* .fi
+/*	Available in Postfix version 2.1 and later:
+/* .IP "\fBsmtp_send_xforward_command (no)\fR"
+/*	Send the non-standard XFORWARD command when the Postfix SMTP server
+/*	EHLO response announces XFORWARD support.
+/* SASL AUTHENTICATION CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBsmtp_sasl_auth_enable (no)\fR"
+/*	Enable SASL authentication in the Postfix SMTP client.
+/* .IP "\fBsmtp_sasl_password_maps (empty)\fR"
+/*	Optional Postfix SMTP client lookup tables with one username:password
+/*	entry per sender, remote hostname or next-hop domain.
+/* .IP "\fBsmtp_sasl_security_options (noplaintext, noanonymous)\fR"
+/*	Postfix SMTP client SASL security options; as of Postfix 2.3
+/*	the list of available
+/*	features depends on the SASL client implementation that is selected
+/*	with \fBsmtp_sasl_type\fR.
+/* .PP
+/*	Available in Postfix version 2.2 and later:
+/* .IP "\fBsmtp_sasl_mechanism_filter (empty)\fR"
+/*	If non-empty, a Postfix SMTP client filter for the remote SMTP
+/*	server's list of offered SASL mechanisms.
+/* .PP
+/*	Available in Postfix version 2.3 and later:
+/* .IP "\fBsmtp_sender_dependent_authentication (no)\fR"
+/*	Enable sender-dependent authentication in the Postfix SMTP client; this is
+/*	available only with SASL authentication, and disables SMTP connection
+/*	caching to ensure that mail from different senders will use the
+/*	appropriate credentials.
+/* .IP "\fBsmtp_sasl_path (empty)\fR"
+/*	Implementation-specific information that the Postfix SMTP client
+/*	passes through to
+/*	the SASL plug-in implementation that is selected with
+/*	\fBsmtp_sasl_type\fR.
+/* .IP "\fBsmtp_sasl_type (cyrus)\fR"
+/*	The SASL plug-in type that the Postfix SMTP client should use
+/*	for authentication.
+/* .PP
+/*	Available in Postfix version 2.5 and later:
+/* .IP "\fBsmtp_sasl_auth_cache_name (empty)\fR"
+/*	An optional table to prevent repeated SASL authentication
+/*	failures with the same remote SMTP server hostname, username and
+/*	password.
+/* .IP "\fBsmtp_sasl_auth_cache_time (90d)\fR"
+/*	The maximal age of an smtp_sasl_auth_cache_name entry before it
+/*	is removed.
+/* .IP "\fBsmtp_sasl_auth_soft_bounce (yes)\fR"
+/*	When a remote SMTP server rejects a SASL authentication request
+/*	with a 535 reply code, defer mail delivery instead of returning
+/*	mail as undeliverable.
+/* .PP
+/*	Available in Postfix version 2.9 and later:
+/* .IP "\fBsmtp_send_dummy_mail_auth (no)\fR"
+/*	Whether or not to append the "AUTH=<>" option to the MAIL
+/*	FROM command in SASL-authenticated SMTP sessions.
+/* STARTTLS SUPPORT CONTROLS
+/* .ad
+/* .fi
+/*	Detailed information about STARTTLS configuration may be found
+/*	in the TLS_README document.
+/* .IP "\fBsmtp_tls_security_level (empty)\fR"
+/*	The default SMTP TLS security level for the Postfix SMTP client;
+/*	when a non-empty value is specified, this overrides the obsolete
+/*	parameters smtp_use_tls, smtp_enforce_tls, and smtp_tls_enforce_peername.
+/* .IP "\fBsmtp_sasl_tls_security_options ($smtp_sasl_security_options)\fR"
+/*	The SASL authentication security options that the Postfix SMTP
+/*	client uses for TLS encrypted SMTP sessions.
+/* .IP "\fBsmtp_starttls_timeout (300s)\fR"
+/*	Time limit for Postfix SMTP client write and read operations
+/*	during TLS startup and shutdown handshake procedures.
+/* .IP "\fBsmtp_tls_CAfile (empty)\fR"
+/*	A file containing CA certificates of root CAs trusted to sign
+/*	either remote SMTP server certificates or intermediate CA certificates.
+/* .IP "\fBsmtp_tls_CApath (empty)\fR"
+/*	Directory with PEM format Certification Authority certificates
+/*	that the Postfix SMTP client uses to verify a remote SMTP server
+/*	certificate.
+/* .IP "\fBsmtp_tls_cert_file (empty)\fR"
+/*	File with the Postfix SMTP client RSA certificate in PEM format.
+/* .IP "\fBsmtp_tls_mandatory_ciphers (medium)\fR"
+/*	The minimum TLS cipher grade that the Postfix SMTP client will
+/*	use with
+/*	mandatory TLS encryption.
+/* .IP "\fBsmtp_tls_exclude_ciphers (empty)\fR"
+/*	List of ciphers or cipher types to exclude from the Postfix
+/*	SMTP client cipher
+/*	list at all TLS security levels.
+/* .IP "\fBsmtp_tls_mandatory_exclude_ciphers (empty)\fR"
+/*	Additional list of ciphers or cipher types to exclude from the
+/*	Postfix SMTP client cipher list at mandatory TLS security levels.
+/* .IP "\fBsmtp_tls_dcert_file (empty)\fR"
+/*	File with the Postfix SMTP client DSA certificate in PEM format.
+/* .IP "\fBsmtp_tls_dkey_file ($smtp_tls_dcert_file)\fR"
+/*	File with the Postfix SMTP client DSA private key in PEM format.
+/* .IP "\fBsmtp_tls_key_file ($smtp_tls_cert_file)\fR"
+/*	File with the Postfix SMTP client RSA private key in PEM format.
+/* .IP "\fBsmtp_tls_loglevel (0)\fR"
+/*	Enable additional Postfix SMTP client logging of TLS activity.
+/* .IP "\fBsmtp_tls_note_starttls_offer (no)\fR"
+/*	Log the hostname of a remote SMTP server that offers STARTTLS,
+/*	when TLS is not already enabled for that server.
+/* .IP "\fBsmtp_tls_policy_maps (empty)\fR"
+/*	Optional lookup tables with the Postfix SMTP client TLS security
+/*	policy by next-hop destination; when a non-empty value is specified,
+/*	this overrides the obsolete smtp_tls_per_site parameter.
+/* .IP "\fBsmtp_tls_mandatory_protocols (!SSLv2, !SSLv3)\fR"
+/*	List of SSL/TLS protocols that the Postfix SMTP client will use with
+/*	mandatory TLS encryption.
+/* .IP "\fBsmtp_tls_scert_verifydepth (9)\fR"
+/*	The verification depth for remote SMTP server certificates.
+/* .IP "\fBsmtp_tls_secure_cert_match (nexthop, dot-nexthop)\fR"
+/*	How the Postfix SMTP client verifies the server certificate
+/*	peername for the "secure" TLS security level.
+/* .IP "\fBsmtp_tls_session_cache_database (empty)\fR"
+/*	Name of the file containing the optional Postfix SMTP client
+/*	TLS session cache.
+/* .IP "\fBsmtp_tls_session_cache_timeout (3600s)\fR"
+/*	The expiration time of Postfix SMTP client TLS session cache
+/*	information.
+/* .IP "\fBsmtp_tls_verify_cert_match (hostname)\fR"
+/*	How the Postfix SMTP client verifies the server certificate
+/*	peername for the
+/*	"verify" TLS security level.
+/* .IP "\fBtls_daemon_random_bytes (32)\fR"
+/*	The number of pseudo-random bytes that an \fBsmtp\fR(8) or \fBsmtpd\fR(8)
+/*	process requests from the \fBtlsmgr\fR(8) server in order to seed its
+/*	internal pseudo random number generator (PRNG).
+/* .IP "\fBtls_high_cipherlist (see 'postconf -d' output)\fR"
+/*	The OpenSSL cipherlist for "high" grade ciphers.
+/* .IP "\fBtls_medium_cipherlist (see 'postconf -d' output)\fR"
+/*	The OpenSSL cipherlist for "medium" or higher grade ciphers.
+/* .IP "\fBtls_low_cipherlist (see 'postconf -d' output)\fR"
+/*	The OpenSSL cipherlist for "low" or higher grade ciphers.
+/* .IP "\fBtls_export_cipherlist (see 'postconf -d' output)\fR"
+/*	The OpenSSL cipherlist for "export" or higher grade ciphers.
+/* .IP "\fBtls_null_cipherlist (eNULL:!aNULL)\fR"
+/*	The OpenSSL cipherlist for "NULL" grade ciphers that provide
+/*	authentication without encryption.
+/* .PP
+/*	Available in Postfix version 2.4 and later:
+/* .IP "\fBsmtp_sasl_tls_verified_security_options ($smtp_sasl_tls_security_options)\fR"
+/*	The SASL authentication security options that the Postfix SMTP
+/*	client uses for TLS encrypted SMTP sessions with a verified server
+/*	certificate.
+/* .PP
+/*	Available in Postfix version 2.5 and later:
+/* .IP "\fBsmtp_tls_fingerprint_cert_match (empty)\fR"
+/*	List of acceptable remote SMTP server certificate fingerprints for
+/*	the "fingerprint" TLS security level (\fBsmtp_tls_security_level\fR =
+/*	fingerprint).
+/* .IP "\fBsmtp_tls_fingerprint_digest (md5)\fR"
+/*	The message digest algorithm used to construct remote SMTP server
+/*	certificate fingerprints.
+/* .PP
+/*	Available in Postfix version 2.6 and later:
+/* .IP "\fBsmtp_tls_protocols (!SSLv2, !SSLv3)\fR"
+/*	List of TLS protocols that the Postfix SMTP client will exclude or
+/*	include with opportunistic TLS encryption.
+/* .IP "\fBsmtp_tls_ciphers (medium)\fR"
+/*	The minimum TLS cipher grade that the Postfix SMTP client
+/*	will use with opportunistic TLS encryption.
+/* .IP "\fBsmtp_tls_eccert_file (empty)\fR"
+/*	File with the Postfix SMTP client ECDSA certificate in PEM format.
+/* .IP "\fBsmtp_tls_eckey_file ($smtp_tls_eccert_file)\fR"
+/*	File with the Postfix SMTP client ECDSA private key in PEM format.
+/* .PP
+/*	Available in Postfix version 2.7 and later:
+/* .IP "\fBsmtp_tls_block_early_mail_reply (no)\fR"
+/*	Try to detect a mail hijacking attack based on a TLS protocol
+/*	vulnerability (CVE-2009-3555), where an attacker prepends malicious
+/*	HELO, MAIL, RCPT, DATA commands to a Postfix SMTP client TLS session.
+/* .PP
+/*	Available in Postfix version 2.8 and later:
+/* .IP "\fBtls_disable_workarounds (see 'postconf -d' output)\fR"
+/*	List or bit-mask of OpenSSL bug work-arounds to disable.
+/* .PP
+/*	Available in Postfix version 2.11-3.1:
+/* .IP "\fBtls_dane_digest_agility (on)\fR"
+/*	Configure RFC7671 DANE TLSA digest algorithm agility.
+/* .IP "\fBtls_dane_trust_anchor_digest_enable (yes)\fR"
+/*	Enable support for RFC 6698 (DANE TLSA) DNS records that contain
+/*	digests of trust-anchors with certificate usage "2".
+/* .PP
+/*	Available in Postfix version 2.11 and later:
+/* .IP "\fBsmtp_tls_trust_anchor_file (empty)\fR"
+/*	Zero or more PEM-format files with trust-anchor certificates
+/*	and/or public keys.
+/* .IP "\fBsmtp_tls_force_insecure_host_tlsa_lookup (no)\fR"
+/*	Lookup the associated DANE TLSA RRset even when a hostname is
+/*	not an alias and its address records lie in an unsigned zone.
+/* .IP "\fBtlsmgr_service_name (tlsmgr)\fR"
+/*	The name of the \fBtlsmgr\fR(8) service entry in master.cf.
+/* .PP
+/*	Available in Postfix version 3.0 and later:
+/* .IP "\fBsmtp_tls_wrappermode (no)\fR"
+/*	Request that the Postfix SMTP client connects using the
+/*	legacy SMTPS protocol instead of using the STARTTLS command.
+/* .PP
+/*	Available in Postfix version 3.1 and later:
+/* .IP "\fBsmtp_tls_dane_insecure_mx_policy (dane)\fR"
+/*	The TLS policy for MX hosts with "secure" TLSA records when the
+/*	nexthop destination security level is \fBdane\fR, but the MX
+/*	record was found via an "insecure" MX lookup.
+/* .PP
+/*	Available in Postfix version 3.4 and later:
+/* .IP "\fBsmtp_tls_connection_reuse (no)\fR"
+/*	Try to make multiple deliveries per TLS-encrypted connection.
+/* .IP "\fBsmtp_tls_chain_files (empty)\fR"
+/*	List of one or more PEM files, each holding one or more private keys
+/*	directly followed by a corresponding certificate chain.
+/* .IP "\fBsmtp_tls_servername (empty)\fR"
+/*	Optional name to send to the remote SMTP server in the TLS Server
+/*	Name Indication (SNI) extension.
+/* .PP
+/*	Available in Postfix 3.5, 3.4.6, 3.3.5, 3.2.10, 3.1.13 and later:
+/* .IP "\fBtls_fast_shutdown_enable (yes)\fR"
+/*	A workaround for implementations that hang Postfix while shutting
+/*	down a TLS session, until Postfix times out.
+/* .PP
+/*	Available in Postfix 3.9, 3.8.1, 3.7.6, 3.6.10, 3.5.20 and later:
+/* .IP "\fBtls_config_file (default)\fR"
+/*	Optional configuration file with baseline OpenSSL settings.
+/* .IP "\fBtls_config_name (empty)\fR"
+/*	The application name passed by Postfix to OpenSSL library
+/*	initialization functions.
+/* OBSOLETE STARTTLS CONTROLS
+/* .ad
+/* .fi
+/*	The following configuration parameters exist for compatibility
+/*	with Postfix versions before 2.3. Support for these will
+/*	be removed in a future release.
+/* .IP "\fBsmtp_use_tls (no)\fR"
+/*	Opportunistic mode: use TLS when a remote SMTP server announces
+/*	STARTTLS support, otherwise send the mail in the clear.
+/* .IP "\fBsmtp_enforce_tls (no)\fR"
+/*	Enforcement mode: require that remote SMTP servers use TLS
+/*	encryption, and never send mail in the clear.
+/* .IP "\fBsmtp_tls_enforce_peername (yes)\fR"
+/*	With mandatory TLS encryption, require that the remote SMTP
+/*	server hostname matches the information in the remote SMTP server
+/*	certificate.
+/* .IP "\fBsmtp_tls_per_site (empty)\fR"
+/*	Optional lookup tables with the Postfix SMTP client TLS usage
+/*	policy by next-hop destination and by remote SMTP server hostname.
+/* .IP "\fBsmtp_tls_cipherlist (empty)\fR"
+/*	Obsolete Postfix < 2.3 control for the Postfix SMTP client TLS
+/*	cipher list.
+/* RESOURCE AND RATE CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBsmtp_connect_timeout (30s)\fR"
+/*	The Postfix SMTP client time limit for completing a TCP connection, or
+/*	zero (use the operating system built-in time limit).
+/* .IP "\fBsmtp_helo_timeout (300s)\fR"
+/*	The Postfix SMTP client time limit for sending the HELO or EHLO command,
+/*	and for receiving the initial remote SMTP server response.
+/* .IP "\fBlmtp_lhlo_timeout (300s)\fR"
+/*	The Postfix LMTP client time limit for sending the LHLO command,
+/*	and for receiving the initial remote LMTP server response.
+/* .IP "\fBsmtp_xforward_timeout (300s)\fR"
+/*	The Postfix SMTP client time limit for sending the XFORWARD command,
+/*	and for receiving the remote SMTP server response.
+/* .IP "\fBsmtp_mail_timeout (300s)\fR"
+/*	The Postfix SMTP client time limit for sending the MAIL FROM command,
+/*	and for receiving the remote SMTP server response.
+/* .IP "\fBsmtp_rcpt_timeout (300s)\fR"
+/*	The Postfix SMTP client time limit for sending the SMTP RCPT TO
+/*	command, and for receiving the remote SMTP server response.
+/* .IP "\fBsmtp_data_init_timeout (120s)\fR"
+/*	The Postfix SMTP client time limit for sending the SMTP DATA command,
+/*	and for receiving the remote SMTP server response.
+/* .IP "\fBsmtp_data_xfer_timeout (180s)\fR"
+/*	The Postfix SMTP client time limit for sending the SMTP message content.
+/* .IP "\fBsmtp_data_done_timeout (600s)\fR"
+/*	The Postfix SMTP client time limit for sending the SMTP ".", and
+/*	for receiving the remote SMTP server response.
+/* .IP "\fBsmtp_quit_timeout (300s)\fR"
+/*	The Postfix SMTP client time limit for sending the QUIT command,
+/*	and for receiving the remote SMTP server response.
+/* .PP
+/*	Available in Postfix version 2.1 and later:
+/* .IP "\fBsmtp_mx_address_limit (5)\fR"
+/*	The maximal number of MX (mail exchanger) IP addresses that can
+/*	result from Postfix SMTP client mail exchanger lookups, or zero (no
+/*	limit).
+/* .IP "\fBsmtp_mx_session_limit (2)\fR"
+/*	The maximal number of SMTP sessions per delivery request before
+/*	the Postfix SMTP client
+/*	gives up or delivers to a fall-back relay host, or zero (no
+/*	limit).
+/* .IP "\fBsmtp_rset_timeout (20s)\fR"
+/*	The Postfix SMTP client time limit for sending the RSET command,
+/*	and for receiving the remote SMTP server response.
+/* .PP
+/*	Available in Postfix version 2.2 and earlier:
+/* .IP "\fBlmtp_cache_connection (yes)\fR"
+/*	Keep Postfix LMTP client connections open for up to $max_idle
+/*	seconds.
+/* .PP
+/*	Available in Postfix version 2.2 and later:
+/* .IP "\fBsmtp_connection_cache_destinations (empty)\fR"
+/*	Permanently enable SMTP connection caching for the specified
+/*	destinations.
+/* .IP "\fBsmtp_connection_cache_on_demand (yes)\fR"
+/*	Temporarily enable SMTP connection caching while a destination
+/*	has a high volume of mail in the active queue.
+/* .IP "\fBsmtp_connection_reuse_time_limit (300s)\fR"
+/*	The amount of time during which Postfix will use an SMTP
+/*	connection repeatedly.
+/* .IP "\fBsmtp_connection_cache_time_limit (2s)\fR"
+/*	When SMTP connection caching is enabled, the amount of time that
+/*	an unused SMTP client socket is kept open before it is closed.
+/* .PP
+/*	Available in Postfix version 2.3 and later:
+/* .IP "\fBconnection_cache_protocol_timeout (5s)\fR"
+/*	Time limit for connection cache connect, send or receive
+/*	operations.
+/* .PP
+/*	Available in Postfix version 2.9 and later:
+/* .IP "\fBsmtp_per_record_deadline (no)\fR"
+/*	Change the behavior of the smtp_*_timeout time limits, from a
+/*	time limit per read or write system call, to a time limit to send
+/*	or receive a complete record (an SMTP command line, SMTP response
+/*	line, SMTP message content line, or TLS protocol message).
+/* .PP
+/*	Available in Postfix version 2.11 and later:
+/* .IP "\fBsmtp_connection_reuse_count_limit (0)\fR"
+/*	When SMTP connection caching is enabled, the number of times
+/*	that an SMTP session may be reused before it is closed, or zero (no
+/*	limit).
+/* .PP
+/*	Available in Postfix version 3.4 and later:
+/* .IP "\fBsmtp_tls_connection_reuse (no)\fR"
+/*	Try to make multiple deliveries per TLS-encrypted connection.
+/* .PP
+/*	Implemented in the qmgr(8) daemon:
+/* .IP "\fBtransport_destination_concurrency_limit ($default_destination_concurrency_limit)\fR"
+/*	A transport-specific override for the
+/*	default_destination_concurrency_limit parameter value, where
+/*	\fItransport\fR is the master.cf name of the message delivery
+/*	transport.
+/* .IP "\fBtransport_destination_recipient_limit ($default_destination_recipient_limit)\fR"
+/*	A transport-specific override for the
+/*	default_destination_recipient_limit parameter value, where
+/*	\fItransport\fR is the master.cf name of the message delivery
+/*	transport.
+/* SMTPUTF8 CONTROLS
+/* .ad
+/* .fi
+/*	Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
+/* .IP "\fBsmtputf8_enable (yes)\fR"
+/*	Enable preliminary SMTPUTF8 support for the protocols described
+/*	in RFC 6531..6533.
+/* .IP "\fBsmtputf8_autodetect_classes (sendmail, verify)\fR"
+/*	Detect that a message requires SMTPUTF8 support for the specified
+/*	mail origin classes.
+/* .PP
+/*	Available in Postfix version 3.2 and later:
+/* .IP "\fBenable_idna2003_compatibility (no)\fR"
+/*	Enable 'transitional' compatibility between IDNA2003 and IDNA2008,
+/*	when converting UTF-8 domain names to/from the ASCII form that is
+/*	used for DNS lookups.
+/* TROUBLE SHOOTING CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBdebug_peer_level (2)\fR"
+/*	The increment in verbose logging level when a remote client or
+/*	server matches a pattern in the debug_peer_list parameter.
+/* .IP "\fBdebug_peer_list (empty)\fR"
+/*	Optional list of remote client or server hostname or network
+/*	address patterns that cause the verbose logging level to increase
+/*	by the amount specified in $debug_peer_level.
+/* .IP "\fBerror_notice_recipient (postmaster)\fR"
+/*	The recipient of postmaster notifications about mail delivery
+/*	problems that are caused by policy, resource, software or protocol
+/*	errors.
+/* .IP "\fBinternal_mail_filter_classes (empty)\fR"
+/*	What categories of Postfix-generated mail are subject to
+/*	before-queue content inspection by non_smtpd_milters, header_checks
+/*	and body_checks.
+/* .IP "\fBnotify_classes (resource, software)\fR"
+/*	The list of error classes that are reported to the postmaster.
+/* MISCELLANEOUS CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBbest_mx_transport (empty)\fR"
+/*	Where the Postfix SMTP client should deliver mail when it detects
+/*	a "mail loops back to myself" error condition.
+/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+/*	The default location of the Postfix main.cf and master.cf
+/*	configuration files.
+/* .IP "\fBdaemon_timeout (18000s)\fR"
+/*	How much time a Postfix daemon process may take to handle a
+/*	request before it is terminated by a built-in watchdog timer.
+/* .IP "\fBdelay_logging_resolution_limit (2)\fR"
+/*	The maximal number of digits after the decimal point when logging
+/*	sub-second delay values.
+/* .IP "\fBdisable_dns_lookups (no)\fR"
+/*	Disable DNS lookups in the Postfix SMTP and LMTP clients.
+/* .IP "\fBinet_interfaces (all)\fR"
+/*	The network interface addresses that this mail system receives
+/*	mail on.
+/* .IP "\fBinet_protocols (all)\fR"
+/*	The Internet protocols Postfix will attempt to use when making
+/*	or accepting connections.
+/* .IP "\fBipc_timeout (3600s)\fR"
+/*	The time limit for sending or receiving information over an internal
+/*	communication channel.
+/* .IP "\fBlmtp_assume_final (no)\fR"
+/*	When a remote LMTP server announces no DSN support, assume that
+/*	the
+/*	server performs final delivery, and send "delivered" delivery status
+/*	notifications instead of "relayed".
+/* .IP "\fBlmtp_tcp_port (24)\fR"
+/*	The default TCP port that the Postfix LMTP client connects to.
+/* .IP "\fBmax_idle (100s)\fR"
+/*	The maximum amount of time that an idle Postfix daemon process waits
+/*	for an incoming connection before terminating voluntarily.
+/* .IP "\fBmax_use (100)\fR"
+/*	The maximal number of incoming connections that a Postfix daemon
+/*	process will service before terminating voluntarily.
+/* .IP "\fBprocess_id (read-only)\fR"
+/*	The process ID of a Postfix command or daemon process.
+/* .IP "\fBprocess_name (read-only)\fR"
+/*	The process name of a Postfix command or daemon process.
+/* .IP "\fBproxy_interfaces (empty)\fR"
+/*	The network interface addresses that this mail system receives mail
+/*	on by way of a proxy or network address translation unit.
+/* .IP "\fBsmtp_address_preference (any)\fR"
+/*	The address type ("ipv6", "ipv4" or "any") that the Postfix
+/*	SMTP client will try first, when a destination has IPv6 and IPv4
+/*	addresses with equal MX preference.
+/* .IP "\fBsmtp_bind_address (empty)\fR"
+/*	An optional numerical network address that the Postfix SMTP client
+/*	should bind to when making an IPv4 connection.
+/* .IP "\fBsmtp_bind_address6 (empty)\fR"
+/*	An optional numerical network address that the Postfix SMTP client
+/*	should bind to when making an IPv6 connection.
+/* .IP "\fBsmtp_helo_name ($myhostname)\fR"
+/*	The hostname to send in the SMTP HELO or EHLO command.
+/* .IP "\fBlmtp_lhlo_name ($myhostname)\fR"
+/*	The hostname to send in the LMTP LHLO command.
+/* .IP "\fBsmtp_host_lookup (dns)\fR"
+/*	What mechanisms the Postfix SMTP client uses to look up a host's
+/*	IP address.
+/* .IP "\fBsmtp_randomize_addresses (yes)\fR"
+/*	Randomize the order of equal-preference MX host addresses.
+/* .IP "\fBsyslog_facility (mail)\fR"
+/*	The syslog facility of Postfix logging.
+/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
+/*	A prefix that is prepended to the process name in syslog
+/*	records, so that, for example, "smtpd" becomes "prefix/smtpd".
+/* .PP
+/*	Available with Postfix 2.2 and earlier:
+/* .IP "\fBfallback_relay (empty)\fR"
+/*	Optional list of relay hosts for SMTP destinations that can't be
+/*	found or that are unreachable.
+/* .PP
+/*	Available with Postfix 2.3 and later:
+/* .IP "\fBsmtp_fallback_relay ($fallback_relay)\fR"
+/*	Optional list of relay hosts for SMTP destinations that can't be
+/*	found or that are unreachable.
+/* .PP
+/*	Available with Postfix 3.0 and later:
+/* .IP "\fBsmtp_address_verify_target (rcpt)\fR"
+/*	In the context of email address verification, the SMTP protocol
+/*	stage that determines whether an email address is deliverable.
+/* .PP
+/*	Available with Postfix 3.1 and later:
+/* .IP "\fBlmtp_fallback_relay (empty)\fR"
+/*	Optional list of relay hosts for LMTP destinations that can't be
+/*	found or that are unreachable.
+/* .PP
+/*	Available with Postfix 3.2 and later:
+/* .IP "\fBsmtp_tcp_port (smtp)\fR"
+/*	The default TCP port that the Postfix SMTP client connects to.
+/* .PP
+/*	Available in Postfix 3.3 and later:
+/* .IP "\fBservice_name (read-only)\fR"
+/*	The master.cf service name of a Postfix daemon process.
+/* SEE ALSO
+/*	generic(5), output address rewriting
+/*	header_checks(5), message header content inspection
+/*	body_checks(5), body parts content inspection
+/*	qmgr(8), queue manager
+/*	bounce(8), delivery status reports
+/*	scache(8), connection cache server
+/*	postconf(5), configuration parameters
+/*	master(5), generic daemon options
+/*	master(8), process manager
+/*	tlsmgr(8), TLS session and PRNG management
+/*	postlogd(8), Postfix logging
+/*	syslogd(8), system logging
+/* README FILES
+/* .ad
+/* .fi
+/*	Use "\fBpostconf readme_directory\fR" or
+/*	"\fBpostconf html_directory\fR" to locate this information.
+/* .na
+/* .nf
+/*	SASL_README, Postfix SASL howto
+/*	TLS_README, Postfix STARTTLS howto
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	Command pipelining in cooperation with:
+/*	Jon Ribbens
+/*	Oaktree Internet Solutions Ltd.,
+/*	Internet House,
+/*	Canal Basin,
+/*	Coventry,
+/*	CV1 4LY, United Kingdom.
+/*
+/*	SASL support originally by:
+/*	Till Franke
+/*	SuSE Rhein/Main AG
+/*	65760 Eschborn, Germany
+/*
+/*	TLS support originally by:
+/*	Lutz Jaenicke
+/*	BTU Cottbus
+/*	Allgemeine Elektrotechnik
+/*	Universitaetsplatz 3-4
+/*	D-03044 Cottbus, Germany
+/*
+/*	Revised TLS and SMTP connection cache support by:
+/*	Victor Duchovni
+/*	Morgan Stanley
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <dict.h>
+#include <stringops.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <name_mask.h>
+#include <name_code.h>
+#include <byte_mask.h>
+
+/* Global library. */
+
+#include <deliver_request.h>
+#include <delivered_hdr.h>
+#include <mail_proto.h>
+#include <mail_params.h>
+#include <mail_version.h>
+#include <mail_conf.h>
+#include <debug_peer.h>
+#include <flush_clnt.h>
+#include <scache.h>
+#include <string_list.h>
+#include <maps.h>
+#include <ext_prop.h>
+
+/* DNS library. */
+
+#include <dns.h>
+
+/* Single server skeleton. */
+
+#include <mail_server.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+ /*
+  * Tunable parameters. These have compiled-in defaults that can be overruled
+  * by settings in the global Postfix configuration file.
+  */
+int     var_smtp_conn_tmout;
+int     var_smtp_helo_tmout;
+int     var_smtp_xfwd_tmout;
+int     var_smtp_mail_tmout;
+int     var_smtp_rcpt_tmout;
+int     var_smtp_data0_tmout;
+int     var_smtp_data1_tmout;
+int     var_smtp_data2_tmout;
+int     var_smtp_rset_tmout;
+int     var_smtp_quit_tmout;
+char   *var_inet_interfaces;
+char   *var_notify_classes;
+int     var_smtp_skip_5xx_greeting;
+int     var_ign_mx_lookup_err;
+int     var_skip_quit_resp;
+char   *var_fallback_relay;
+char   *var_bestmx_transp;
+char   *var_error_rcpt;
+int     var_smtp_always_ehlo;
+int     var_smtp_never_ehlo;
+char   *var_smtp_sasl_opts;
+char   *var_smtp_sasl_path;
+char   *var_smtp_sasl_passwd;
+bool    var_smtp_sasl_enable;
+char   *var_smtp_sasl_mechs;
+char   *var_smtp_sasl_type;
+char   *var_smtp_bind_addr;
+char   *var_smtp_bind_addr6;
+char   *var_smtp_vrfy_tgt;
+bool    var_smtp_rand_addr;
+int     var_smtp_pix_thresh;
+int     var_queue_run_delay;
+int     var_min_backoff_time;
+int     var_smtp_pix_delay;
+int     var_smtp_line_limit;
+char   *var_smtp_helo_name;
+char   *var_smtp_host_lookup;
+bool    var_smtp_quote_821_env;
+bool    var_smtp_defer_mxaddr;
+bool    var_smtp_send_xforward;
+int     var_smtp_mxaddr_limit;
+int     var_smtp_mxsess_limit;
+int     var_smtp_cache_conn;
+int     var_smtp_reuse_time;
+int     var_smtp_reuse_count;
+char   *var_smtp_cache_dest;
+char   *var_scache_service;		/* You can now leave this here. */
+bool    var_smtp_cache_demand;
+char   *var_smtp_ehlo_dis_words;
+char   *var_smtp_ehlo_dis_maps;
+char   *var_smtp_addr_pref;
+
+char   *var_smtp_tls_level;
+bool    var_smtp_use_tls;
+bool    var_smtp_enforce_tls;
+char   *var_smtp_tls_per_site;
+char   *var_smtp_tls_policy;
+bool    var_smtp_tls_wrappermode;
+bool    var_smtp_tls_conn_reuse;
+char   *var_tlsproxy_service;
+
+#ifdef USE_TLS
+char   *var_smtp_sasl_tls_opts;
+char   *var_smtp_sasl_tlsv_opts;
+int     var_smtp_starttls_tmout;
+char   *var_smtp_tls_CAfile;
+char   *var_smtp_tls_CApath;
+char   *var_smtp_tls_chain_files;
+char   *var_smtp_tls_cert_file;
+char   *var_smtp_tls_mand_ciph;
+char   *var_smtp_tls_excl_ciph;
+char   *var_smtp_tls_mand_excl;
+char   *var_smtp_tls_dcert_file;
+char   *var_smtp_tls_dkey_file;
+bool    var_smtp_tls_enforce_peername;
+char   *var_smtp_tls_key_file;
+char   *var_smtp_tls_loglevel;
+bool    var_smtp_tls_note_starttls_offer;
+char   *var_smtp_tls_mand_proto;
+char   *var_smtp_tls_sec_cmatch;
+int     var_smtp_tls_scert_vd;
+char   *var_smtp_tls_vfy_cmatch;
+char   *var_smtp_tls_fpt_cmatch;
+char   *var_smtp_tls_fpt_dgst;
+char   *var_smtp_tls_tafile;
+char   *var_smtp_tls_proto;
+char   *var_smtp_tls_ciph;
+char   *var_smtp_tls_eccert_file;
+char   *var_smtp_tls_eckey_file;
+char   *var_smtp_tls_sni;
+bool    var_smtp_tls_blk_early_mail_reply;
+bool    var_smtp_tls_force_tlsa;
+char   *var_smtp_tls_insecure_mx_policy;
+
+#endif
+
+char   *var_smtp_generic_maps;
+char   *var_prop_extension;
+bool    var_smtp_sender_auth;
+char   *var_smtp_tcp_port;
+int     var_scache_proto_tmout;
+bool    var_smtp_cname_overr;
+char   *var_smtp_pix_bug_words;
+char   *var_smtp_pix_bug_maps;
+char   *var_cyrus_conf_path;
+char   *var_smtp_head_chks;
+char   *var_smtp_mime_chks;
+char   *var_smtp_nest_chks;
+char   *var_smtp_body_chks;
+char   *var_smtp_resp_filter;
+bool    var_lmtp_assume_final;
+char   *var_smtp_dns_res_opt;
+char   *var_smtp_dns_support;
+bool    var_smtp_rec_deadline;
+bool    var_smtp_dummy_mail_auth;
+char   *var_smtp_dsn_filter;
+char   *var_smtp_dns_re_filter;
+bool    var_smtp_balance_inet_proto;
+
+ /* Special handling of 535 AUTH errors. */
+char   *var_smtp_sasl_auth_cache_name;
+int     var_smtp_sasl_auth_cache_time;
+bool    var_smtp_sasl_auth_soft_bounce;
+
+ /*
+  * Global variables.
+  */
+int     smtp_mode;
+int     smtp_host_lookup_mask;
+int     smtp_dns_support;
+STRING_LIST *smtp_cache_dest;
+SCACHE *smtp_scache;
+MAPS   *smtp_ehlo_dis_maps;
+MAPS   *smtp_generic_maps;
+int     smtp_ext_prop_mask;
+unsigned smtp_dns_res_opt;
+MAPS   *smtp_pix_bug_maps;
+HBC_CHECKS *smtp_header_checks;		/* limited header checks */
+HBC_CHECKS *smtp_body_checks;		/* limited body checks */
+SMTP_CLI_ATTR smtp_cli_attr;		/* parsed command-line */
+
+#ifdef USE_TLS
+
+ /*
+  * OpenSSL client state (opaque handle)
+  */
+TLS_APPL_STATE *smtp_tls_ctx;
+int     smtp_tls_insecure_mx_policy;
+
+#endif
+
+ /*
+  * IPv6 preference.
+  */
+static int smtp_addr_pref;
+
+/* get_cli_attr - get command-line attributes */
+
+static void get_cli_attr(SMTP_CLI_ATTR *attr, char **argv)
+{
+    const char myname[] = "get_cli_attr";
+    const char *last_flags = "flags=";	/* i.e. empty */
+    static const BYTE_MASK flags_map[] = {
+	'D', SMTP_CLI_FLAG_DELIVERED_TO,
+	'O', SMTP_CLI_FLAG_ORIG_RCPT,
+	'R', SMTP_CLI_FLAG_RETURN_PATH,
+	'X', SMTP_CLI_FLAG_FINAL_DELIVERY,
+	0,
+    };
+
+    /*
+     * Initialize.
+     */
+    attr->flags = 0;
+
+    /*
+     * Iterate over the command-line attribute list. Errors are fatal.
+     */
+    for ( /* void */ ; *argv != 0; argv++) {
+
+	/*
+	 * flags=stuff. Errors are fatal.
+	 */
+	if (strncasecmp("flags=", *argv, sizeof("flags=") - 1) == 0) {
+	    last_flags = *argv;
+	    if (msg_verbose)
+		msg_info("%s: %s", myname, last_flags);
+	    attr->flags = byte_mask(*argv, flags_map,
+				    *argv + sizeof("flags=") - 1);
+	}
+
+	/*
+	 * Bad.
+	 */
+	else
+	    msg_fatal("unknown attribute name: %s", *argv);
+    }
+
+    /*
+     * Backwards compatibility, redundancy, and obsolescence.
+     */
+    if (!smtp_mode && var_lmtp_assume_final
+	&& (attr->flags & SMTP_CLI_FLAG_FINAL_DELIVERY) == 0) {
+	attr->flags |= SMTP_CLI_FLAG_FINAL_DELIVERY;
+	msg_warn("%s is obsolete; instead, specify \"%sX\" in %s",
+		 VAR_LMTP_ASSUME_FINAL, last_flags, MASTER_CONF_FILE);
+    }
+}
+
+/* deliver_message - deliver message with extreme prejudice */
+
+static int deliver_message(const char *service, DELIVER_REQUEST *request)
+{
+    SMTP_STATE *state;
+    int     result;
+
+    if (msg_verbose)
+	msg_info("deliver_message: from %s", request->sender);
+
+    /*
+     * Sanity checks. The smtp server is unprivileged and chrooted, so we can
+     * afford to distribute the data censoring code, instead of having it all
+     * in one place.
+     */
+    if (request->nexthop[0] == 0)
+	msg_fatal("empty nexthop hostname");
+    if (request->rcpt_list.len <= 0)
+	msg_fatal("recipient count: %d", request->rcpt_list.len);
+
+    /*
+     * D flag checks.
+     */
+    if (smtp_cli_attr.flags & SMTP_CLI_FLAG_DELIVERED_TO) {
+
+	/*
+	 * The D flag cannot be specified for multi-recipient deliveries.
+	 */
+	if (request->rcpt_list.len > 1) {
+	    msg_warn("flag `D' requires %s_destination_recipient_limit = 1",
+		     service);
+	    return (reject_deliver_request(service, request, "4.3.5",
+					"mail system configuration error"));
+	}
+
+	/*
+	 * The recipient cannot appear in a Delivered-To: header.
+	 */
+	else {
+	    DELIVERED_HDR_INFO *delivered_info = delivered_hdr_init(
+			  request->fp, request->data_offset, FOLD_ADDR_ALL);
+	    VSTRING *generic_rcpt = vstring_alloc(100);
+	    int     have_delivered_loop;
+
+	    smtp_rewrite_generic_internal(generic_rcpt,
+					  request->rcpt_list.info->address);
+	    have_delivered_loop = delivered_hdr_find(
+					 delivered_info, STR(generic_rcpt));
+	    vstring_free(generic_rcpt);
+	    delivered_hdr_free(delivered_info);
+	    if (have_delivered_loop) {
+		return (reject_deliver_request(service, request, "5.4.6",
+					       "mail forwarding loop for %s",
+					 request->rcpt_list.info->address));
+	    }
+	}
+    }
+
+    /*
+     * The O flag cannot be specified for multi-recipient deliveries.
+     */
+    if ((smtp_cli_attr.flags & SMTP_CLI_FLAG_ORIG_RCPT)
+	&& request->rcpt_list.len > 1) {
+	msg_warn("flag `O' requires %s_destination_recipient_limit = 1",
+		 service);
+	return (reject_deliver_request(service, request, "4.3.5",
+				       "mail system configuration error"));
+    }
+
+    /*
+     * Initialize. Bundle all information about the delivery request, so that
+     * we can produce understandable diagnostics when something goes wrong
+     * many levels below. The alternative would be to make everything global.
+     */
+    state = smtp_state_alloc();
+    state->request = request;
+    state->src = request->fp;
+    state->service = service;
+    state->misc_flags |= smtp_addr_pref;
+    SMTP_RCPT_INIT(state);
+
+    /*
+     * Establish an SMTP session and deliver this message to all requested
+     * recipients. At the end, notify the postmaster of any protocol errors.
+     * Optionally deliver mail locally when this machine is the best mail
+     * exchanger.
+     */
+    result = smtp_connect(state);
+
+    /*
+     * Clean up.
+     */
+    smtp_state_free(state);
+
+    return (result);
+}
+
+/* smtp_service - perform service for client */
+
+static void smtp_service(VSTREAM *client_stream, char *service,
+			         char **unused_argv)
+{
+    DELIVER_REQUEST *request;
+    int     status;
+
+    /*
+     * This routine runs whenever a client connects to the UNIX-domain socket
+     * dedicated to remote SMTP delivery service. What we see below is a
+     * little protocol to (1) tell the queue manager that we are ready, (2)
+     * read a request from the queue manager, and (3) report the completion
+     * status of that request. All connection-management stuff is handled by
+     * the common code in single_server.c.
+     */
+    if ((request = deliver_request_read(client_stream)) != 0) {
+	status = deliver_message(service, request);
+	deliver_request_done(client_stream, request, status);
+    }
+}
+
+/* post_init - post-jail initialization */
+
+static void post_init(char *unused_name, char **argv)
+{
+    static const NAME_MASK lookup_masks[] = {
+	SMTP_HOST_LOOKUP_DNS, SMTP_HOST_FLAG_DNS,
+	SMTP_HOST_LOOKUP_NATIVE, SMTP_HOST_FLAG_NATIVE,
+	0,
+    };
+    static const NAME_MASK dns_res_opt_masks[] = {
+	SMTP_DNS_RES_OPT_DEFNAMES, RES_DEFNAMES,
+	SMTP_DNS_RES_OPT_DNSRCH, RES_DNSRCH,
+	0,
+    };
+    static const NAME_CODE dns_support[] = {
+	SMTP_DNS_SUPPORT_DISABLED, SMTP_DNS_DISABLED,
+	SMTP_DNS_SUPPORT_ENABLED, SMTP_DNS_ENABLED,
+#if (RES_USE_DNSSEC != 0) && (RES_USE_EDNS0 != 0)
+	SMTP_DNS_SUPPORT_DNSSEC, SMTP_DNS_DNSSEC,
+#endif
+	0, SMTP_DNS_INVALID,
+    };
+
+    if (*var_smtp_dns_support == 0) {
+	/* Backwards compatible empty setting */
+	smtp_dns_support =
+	    var_disable_dns ? SMTP_DNS_DISABLED : SMTP_DNS_ENABLED;
+    } else {
+	smtp_dns_support =
+	    name_code(dns_support, NAME_CODE_FLAG_NONE, var_smtp_dns_support);
+	if (smtp_dns_support == SMTP_DNS_INVALID)
+	    msg_fatal("invalid %s: \"%s\"", VAR_LMTP_SMTP(DNS_SUPPORT),
+		      var_smtp_dns_support);
+	var_disable_dns = (smtp_dns_support == SMTP_DNS_DISABLED);
+    }
+
+#ifdef USE_TLS
+    if (smtp_mode) {
+	smtp_tls_insecure_mx_policy =
+	    tls_level_lookup(var_smtp_tls_insecure_mx_policy);
+	switch (smtp_tls_insecure_mx_policy) {
+	case TLS_LEV_MAY:
+	case TLS_LEV_ENCRYPT:
+	case TLS_LEV_DANE:
+	    break;
+	default:
+	    msg_fatal("invalid %s: \"%s\"", VAR_SMTP_TLS_INSECURE_MX_POLICY,
+		      var_smtp_tls_insecure_mx_policy);
+	}
+    }
+#endif
+
+    /*
+     * Select hostname lookup mechanisms.
+     */
+    if (smtp_dns_support == SMTP_DNS_DISABLED)
+	smtp_host_lookup_mask = SMTP_HOST_FLAG_NATIVE;
+    else
+	smtp_host_lookup_mask =
+	    name_mask(VAR_LMTP_SMTP(HOST_LOOKUP), lookup_masks,
+		      var_smtp_host_lookup);
+    if (msg_verbose)
+	msg_info("host name lookup methods: %s",
+		 str_name_mask(VAR_LMTP_SMTP(HOST_LOOKUP), lookup_masks,
+			       smtp_host_lookup_mask));
+
+    /*
+     * Session cache instance.
+     */
+    if (*var_smtp_cache_dest || var_smtp_cache_demand)
+#if 0
+	smtp_scache = scache_multi_create();
+#else
+	smtp_scache = scache_clnt_create(var_scache_service,
+					 var_scache_proto_tmout,
+					 var_ipc_idle_limit,
+					 var_ipc_ttl_limit);
+#endif
+
+    /*
+     * Select DNS query flags.
+     */
+    smtp_dns_res_opt = name_mask(VAR_LMTP_SMTP(DNS_RES_OPT), dns_res_opt_masks,
+				 var_smtp_dns_res_opt);
+
+    /*
+     * Address verification.
+     */
+    smtp_vrfy_init();
+
+    /*
+     * Look up service command-line attributes; these do not change during
+     * the process lifetime.
+     */
+    get_cli_attr(&smtp_cli_attr, argv);
+}
+
+/* pre_init - pre-jail initialization */
+
+static void pre_init(char *unused_name, char **unused_argv)
+{
+    int     use_tls;
+    static const NAME_CODE addr_pref_map[] = {
+	INET_PROTO_NAME_IPV6, SMTP_MISC_FLAG_PREF_IPV6,
+	INET_PROTO_NAME_IPV4, SMTP_MISC_FLAG_PREF_IPV4,
+	INET_PROTO_NAME_ANY, 0,
+	0, -1,
+    };
+
+    /*
+     * Turn on per-peer debugging.
+     */
+    debug_peer_init();
+
+    /*
+     * SASL initialization.
+     */
+    if (var_smtp_sasl_enable)
+#ifdef USE_SASL_AUTH
+	smtp_sasl_initialize();
+#else
+	msg_warn("%s is true, but SASL support is not compiled in",
+		 VAR_LMTP_SMTP(SASL_ENABLE));
+#endif
+
+    if (*var_smtp_tls_level != 0)
+	switch (tls_level_lookup(var_smtp_tls_level)) {
+	case TLS_LEV_SECURE:
+	case TLS_LEV_VERIFY:
+	case TLS_LEV_DANE_ONLY:
+	case TLS_LEV_FPRINT:
+	case TLS_LEV_ENCRYPT:
+	    var_smtp_use_tls = var_smtp_enforce_tls = 1;
+	    break;
+	case TLS_LEV_DANE:
+	case TLS_LEV_MAY:
+	    var_smtp_use_tls = 1;
+	    var_smtp_enforce_tls = 0;
+	    break;
+	case TLS_LEV_NONE:
+	    var_smtp_use_tls = var_smtp_enforce_tls = 0;
+	    break;
+	default:
+	    /* tls_level_lookup() logs no warning. */
+	    /* session_tls_init() assumes that var_smtp_tls_level is sane. */
+	    msg_fatal("Invalid TLS level \"%s\"", var_smtp_tls_level);
+	}
+    use_tls = (var_smtp_use_tls || var_smtp_enforce_tls);
+
+    /*
+     * Initialize the TLS data before entering the chroot jail
+     */
+    if (use_tls || var_smtp_tls_per_site[0] || var_smtp_tls_policy[0]) {
+#ifdef USE_TLS
+	TLS_CLIENT_INIT_PROPS props;
+
+	tls_pre_jail_init(TLS_ROLE_CLIENT);
+
+	/*
+	 * We get stronger type safety and a cleaner interface by combining
+	 * the various parameters into a single tls_client_props structure.
+	 * 
+	 * Large parameter lists are error-prone, so we emulate a language
+	 * feature that C does not have natively: named parameter lists.
+	 * 
+	 * With tlsproxy(8) turned on, this is still needed for DANE-related
+	 * initializations.
+	 */
+	smtp_tls_ctx =
+	    TLS_CLIENT_INIT(&props,
+			    log_param = VAR_LMTP_SMTP(TLS_LOGLEVEL),
+			    log_level = var_smtp_tls_loglevel,
+			    verifydepth = var_smtp_tls_scert_vd,
+			    cache_type = LMTP_SMTP_SUFFIX(TLS_MGR_SCACHE),
+			    chain_files = var_smtp_tls_chain_files,
+			    cert_file = var_smtp_tls_cert_file,
+			    key_file = var_smtp_tls_key_file,
+			    dcert_file = var_smtp_tls_dcert_file,
+			    dkey_file = var_smtp_tls_dkey_file,
+			    eccert_file = var_smtp_tls_eccert_file,
+			    eckey_file = var_smtp_tls_eckey_file,
+			    CAfile = var_smtp_tls_CAfile,
+			    CApath = var_smtp_tls_CApath,
+			    mdalg = var_smtp_tls_fpt_dgst);
+	smtp_tls_list_init();
+#else
+	msg_warn("TLS has been selected, but TLS support is not compiled in");
+#endif
+    }
+
+    /*
+     * Flush client.
+     */
+    flush_init();
+
+    /*
+     * Session cache domain list.
+     */
+    if (*var_smtp_cache_dest)
+	smtp_cache_dest = string_list_init(VAR_SMTP_CACHE_DEST,
+					   MATCH_FLAG_RETURN,
+					   var_smtp_cache_dest);
+
+    /*
+     * EHLO keyword filter.
+     */
+    if (*var_smtp_ehlo_dis_maps)
+	smtp_ehlo_dis_maps = maps_create(VAR_LMTP_SMTP(EHLO_DIS_MAPS),
+					 var_smtp_ehlo_dis_maps,
+					 DICT_FLAG_LOCK);
+
+    /*
+     * PIX bug workarounds.
+     */
+    if (*var_smtp_pix_bug_maps)
+	smtp_pix_bug_maps = maps_create(VAR_LMTP_SMTP(PIX_BUG_MAPS),
+					var_smtp_pix_bug_maps,
+					DICT_FLAG_LOCK);
+
+    /*
+     * Generic maps.
+     */
+    if (*var_prop_extension)
+	smtp_ext_prop_mask =
+	    ext_prop_mask(VAR_PROP_EXTENSION, var_prop_extension);
+    if (*var_smtp_generic_maps)
+	smtp_generic_maps =
+	    maps_create(VAR_LMTP_SMTP(GENERIC_MAPS), var_smtp_generic_maps,
+			DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX
+			| DICT_FLAG_UTF8_REQUEST);
+
+    /*
+     * Header/body checks.
+     */
+    smtp_header_checks = hbc_header_checks_create(
+			       VAR_LMTP_SMTP(HEAD_CHKS), var_smtp_head_chks,
+			       VAR_LMTP_SMTP(MIME_CHKS), var_smtp_mime_chks,
+			       VAR_LMTP_SMTP(NEST_CHKS), var_smtp_nest_chks,
+						  smtp_hbc_callbacks);
+    smtp_body_checks = hbc_body_checks_create(
+			       VAR_LMTP_SMTP(BODY_CHKS), var_smtp_body_chks,
+					      smtp_hbc_callbacks);
+
+    /*
+     * Server reply filter.
+     */
+    if (*var_smtp_resp_filter)
+	smtp_chat_resp_filter =
+	    dict_open(var_smtp_resp_filter, O_RDONLY,
+		      DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX);
+
+    /*
+     * Address family preference.
+     */
+    if (*var_smtp_addr_pref) {
+	smtp_addr_pref = name_code(addr_pref_map, NAME_CODE_FLAG_NONE,
+				   var_smtp_addr_pref);
+	if (smtp_addr_pref < 0)
+	    msg_fatal("bad %s value: %s", VAR_LMTP_SMTP(ADDR_PREF),
+		      var_smtp_addr_pref);
+    }
+
+    /*
+     * DNS reply filter.
+     */
+    if (*var_smtp_dns_re_filter)
+	dns_rr_filter_compile(VAR_LMTP_SMTP(DNS_RE_FILTER),
+			      var_smtp_dns_re_filter);
+}
+
+/* pre_accept - see if tables have changed */
+
+static void pre_accept(char *unused_name, char **unused_argv)
+{
+    const char *table;
+
+    if ((table = dict_changed_name()) != 0) {
+	msg_info("table %s has changed -- restarting", table);
+	exit(0);
+    }
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* main - pass control to the single-threaded skeleton */
+
+int     main(int argc, char **argv)
+{
+    char   *sane_procname;
+
+#include "smtp_params.c"
+#include "lmtp_params.c"
+
+    /*
+     * Fingerprint executables and core dumps.
+     */
+    MAIL_VERSION_STAMP_ALLOCATE;
+
+    /*
+     * XXX At this point, var_procname etc. are not initialized.
+     * 
+     * The process name, "smtp" or "lmtp", determines the protocol, the DSN
+     * server reply type, SASL service information lookup, and more. Prepare
+     * for the possibility there may be another personality.
+     */
+    sane_procname = sane_basename((VSTRING *) 0, argv[0]);
+    if (strcmp(sane_procname, "smtp") == 0)
+	smtp_mode = 1;
+    else if (strcmp(sane_procname, "lmtp") == 0)
+	smtp_mode = 0;
+    else
+	/* TODO: logging is not initialized. */
+	msg_fatal("unexpected process name \"%s\" - "
+		  "specify \"smtp\" or \"lmtp\"", var_procname);
+
+    /*
+     * Initialize with the LMTP or SMTP parameter name space.
+     */
+    single_server_main(argc, argv, smtp_service,
+		       CA_MAIL_SERVER_TIME_TABLE(smtp_mode ?
+					 smtp_time_table : lmtp_time_table),
+		       CA_MAIL_SERVER_INT_TABLE(smtp_mode ?
+					   smtp_int_table : lmtp_int_table),
+		       CA_MAIL_SERVER_STR_TABLE(smtp_mode ?
+					   smtp_str_table : lmtp_str_table),
+		       CA_MAIL_SERVER_BOOL_TABLE(smtp_mode ?
+					 smtp_bool_table : lmtp_bool_table),
+		       CA_MAIL_SERVER_PRE_INIT(pre_init),
+		       CA_MAIL_SERVER_POST_INIT(post_init),
+		       CA_MAIL_SERVER_PRE_ACCEPT(pre_accept),
+		       CA_MAIL_SERVER_BOUNCE_INIT(VAR_SMTP_DSN_FILTER,
+						  &var_smtp_dsn_filter),
+		       0);
+}
diff --git a/src/smtp/smtp.h b/src/smtp/smtp.h
new file mode 100644
index 0000000..4fea37a
--- /dev/null
+++ b/src/smtp/smtp.h
@@ -0,0 +1,754 @@
+/*++
+/* NAME
+/*	smtp 3h
+/* SUMMARY
+/*	smtp client program
+/* SYNOPSIS
+/*	#include "smtp.h"
+/* DESCRIPTION
+/* .nf
+
+ /*
+  * System library.
+  */
+#include <string.h>
+
+ /*
+  * Utility library.
+  */
+#include <vstream.h>
+#include <vstring.h>
+#include <argv.h>
+#include <htable.h>
+#include <dict.h>
+
+ /*
+  * Global library.
+  */
+#include <deliver_request.h>
+#include <scache.h>
+#include <string_list.h>
+#include <maps.h>
+#include <tok822.h>
+#include <dsn_buf.h>
+#include <header_body_checks.h>
+
+ /*
+  * Postfix TLS library.
+  */
+#include <tls.h>
+
+ /*
+  * tlsproxy client.
+  */
+#include <tls_proxy.h>
+
+ /*
+  * Global iterator support. This is updated by the connection-management
+  * loop, and contains dynamic context that appears in lookup keys for SASL
+  * passwords, TLS policy, cached SMTP connections, and cached TLS session
+  * keys.
+  * 
+  * For consistency and maintainability, context that is used in more than one
+  * lookup key is formatted with smtp_key_format().
+  */
+typedef struct SMTP_ITERATOR {
+    /* Public members. */
+    VSTRING *request_nexthop;		/* delivery request nexhop or empty */
+    VSTRING *dest;			/* current nexthop */
+    VSTRING *host;			/* hostname or empty */
+    VSTRING *addr;			/* printable address or empty */
+    unsigned port;			/* network byte order or null */
+    struct DNS_RR *rr;			/* DNS resource record or null */
+    struct DNS_RR *mx;			/* DNS resource record or null */
+    /* Private members. */
+    VSTRING *saved_dest;		/* saved current nexthop */
+    struct SMTP_STATE *parent;		/* parent linkage */
+} SMTP_ITERATOR;
+
+#define SMTP_ITER_INIT(iter, _dest, _host, _addr, _port, state) do { \
+	vstring_strcpy((iter)->dest, (_dest)); \
+	vstring_strcpy((iter)->host, (_host)); \
+	vstring_strcpy((iter)->addr, (_addr)); \
+	(iter)->port = (_port); \
+	(iter)->mx = (iter)->rr = 0; \
+	vstring_strcpy((iter)->saved_dest, ""); \
+	(iter)->parent = (state); \
+    } while (0)
+
+#define SMTP_ITER_SAVE_DEST(iter) do { \
+	vstring_strcpy((iter)->saved_dest, STR((iter)->dest)); \
+    } while (0)
+
+#define SMTP_ITER_RESTORE_DEST(iter) do { \
+	vstring_strcpy((iter)->dest, STR((iter)->saved_dest)); \
+    } while (0)
+
+ /*
+  * TLS Policy support.
+  */
+#ifdef USE_TLS
+
+typedef struct SMTP_TLS_POLICY {
+    int     level;			/* TLS enforcement level */
+    char   *protocols;			/* Acceptable SSL protocols */
+    char   *grade;			/* Cipher grade: "export", ... */
+    VSTRING *exclusions;		/* Excluded SSL ciphers */
+    ARGV   *matchargv;			/* Cert match patterns */
+    DSN_BUF *why;			/* Lookup error status */
+    TLS_DANE *dane;			/* DANE TLSA digests */
+    char   *sni;			/* Optional SNI name when not DANE */
+    int     conn_reuse;			/* enable connection reuse */
+} SMTP_TLS_POLICY;
+
+ /*
+  * smtp_tls_policy.c
+  */
+extern void smtp_tls_list_init(void);
+extern int smtp_tls_policy_cache_query(DSN_BUF *, SMTP_TLS_POLICY *, SMTP_ITERATOR *);
+extern void smtp_tls_policy_cache_flush(void);
+
+ /*
+  * Macros must use distinct names for local temporary variables, otherwise
+  * there will be bugs due to shadowing. This happened when an earlier
+  * version of smtp_tls_policy_dummy() invoked smtp_tls_policy_init(), but it
+  * could also happen without macro nesting.
+  * 
+  * General principle: use all or part of the macro name in each temporary
+  * variable name. Then, append suffixes to the names if needed.
+  */
+#define smtp_tls_policy_dummy(t) do { \
+	SMTP_TLS_POLICY *_tls_policy_dummy_tmp = (t); \
+	smtp_tls_policy_init(_tls_policy_dummy_tmp, (DSN_BUF *) 0); \
+	_tls_policy_dummy_tmp->level = TLS_LEV_NONE; \
+    } while (0)
+
+ /* This macro is not part of the module external interface. */
+#define smtp_tls_policy_init(t, w) do { \
+	SMTP_TLS_POLICY *_tls_policy_init_tmp = (t); \
+	_tls_policy_init_tmp->protocols = 0; \
+	_tls_policy_init_tmp->grade = 0; \
+	_tls_policy_init_tmp->exclusions = 0; \
+	_tls_policy_init_tmp->matchargv = 0; \
+	_tls_policy_init_tmp->why = (w); \
+	_tls_policy_init_tmp->dane = 0; \
+	_tls_policy_init_tmp->sni = 0; \
+	_tls_policy_init_tmp->conn_reuse = 0; \
+    } while (0)
+
+#endif
+
+ /*
+  * State information associated with each SMTP delivery request.
+  * Session-specific state is stored separately.
+  */
+typedef struct SMTP_STATE {
+    int     misc_flags;			/* processing flags, see below */
+    VSTREAM *src;			/* queue file stream */
+    const char *service;		/* transport name */
+    DELIVER_REQUEST *request;		/* envelope info, offsets */
+    struct SMTP_SESSION *session;	/* network connection */
+    int     status;			/* delivery status */
+    ssize_t space_left;			/* output length control */
+
+    /*
+     * Global iterator.
+     */
+    SMTP_ITERATOR iterator[1];		/* Usage: state->iterator->member */
+
+    /*
+     * Global iterator.
+     */
+#ifdef USE_TLS
+    SMTP_TLS_POLICY tls[1];		/* Usage: state->tls->member */
+#endif
+
+    /*
+     * Connection cache support.
+     */
+    HTABLE *cache_used;			/* cached addresses that were used */
+    VSTRING *dest_label;		/* cached logical/physical binding */
+    VSTRING *dest_prop;			/* binding properties, passivated */
+    VSTRING *endp_label;		/* cached session physical endpoint */
+    VSTRING *endp_prop;			/* endpoint properties, passivated */
+
+    /*
+     * Flags and counters to control the handling of mail delivery errors.
+     * There is some redundancy for sanity checking. At the end of an SMTP
+     * session all recipients should be marked one way or the other.
+     */
+    int     rcpt_left;			/* recipients left over */
+    int     rcpt_drop;			/* recipients marked as drop */
+    int     rcpt_keep;			/* recipients marked as keep */
+
+    /*
+     * DSN Support introduced major bloat in error processing.
+     */
+    DSN_BUF *why;			/* on-the-fly formatting buffer */
+} SMTP_STATE;
+
+ /*
+  * Primitives to enable/disable/test connection caching and reuse based on
+  * the delivery request next-hop destination (i.e. not smtp_fallback_relay).
+  * 
+  * Connection cache lookup by the delivery request next-hop destination allows
+  * a reuse request to skip over bad hosts, and may result in a connection to
+  * a fall-back relay. Once we have found a 'good' host for a delivery
+  * request next-hop, clear the delivery request next-hop destination, to
+  * avoid caching less-preferred connections under that same delivery request
+  * next-hop.
+  */
+#define SET_SCACHE_REQUEST_NEXTHOP(state, nexthop) do { \
+	vstring_strcpy((state)->iterator->request_nexthop, nexthop); \
+    } while (0)
+
+#define CLEAR_SCACHE_REQUEST_NEXTHOP(state) do { \
+	STR((state)->iterator->request_nexthop)[0] = 0; \
+    } while (0)
+
+#define HAVE_SCACHE_REQUEST_NEXTHOP(state) \
+	(STR((state)->iterator->request_nexthop)[0] != 0)
+
+
+ /*
+  * Server features.
+  */
+#define SMTP_FEATURE_ESMTP		(1<<0)
+#define SMTP_FEATURE_8BITMIME		(1<<1)
+#define SMTP_FEATURE_PIPELINING		(1<<2)
+#define SMTP_FEATURE_SIZE		(1<<3)
+#define SMTP_FEATURE_STARTTLS		(1<<4)
+#define SMTP_FEATURE_AUTH		(1<<5)
+#define SMTP_FEATURE_XFORWARD_NAME	(1<<7)
+#define SMTP_FEATURE_XFORWARD_ADDR	(1<<8)
+#define SMTP_FEATURE_XFORWARD_PROTO	(1<<9)
+#define SMTP_FEATURE_XFORWARD_HELO	(1<<10)
+#define SMTP_FEATURE_XFORWARD_DOMAIN	(1<<11)
+#define SMTP_FEATURE_BEST_MX		(1<<12)	/* for next-hop or fall-back */
+#define SMTP_FEATURE_RSET_REJECTED	(1<<13)	/* RSET probe rejected */
+#define SMTP_FEATURE_FROM_CACHE		(1<<14)	/* cached connection */
+#define SMTP_FEATURE_DSN		(1<<15)	/* DSN supported */
+#define SMTP_FEATURE_PIX_NO_ESMTP	(1<<16)	/* PIX smtp fixup mode */
+#define SMTP_FEATURE_PIX_DELAY_DOTCRLF	(1<<17)	/* PIX smtp fixup mode */
+#define SMTP_FEATURE_XFORWARD_PORT	(1<<18)
+#define SMTP_FEATURE_EARLY_TLS_MAIL_REPLY (1<<19)	/* CVE-2009-3555 */
+#define SMTP_FEATURE_XFORWARD_IDENT	(1<<20)
+#define SMTP_FEATURE_SMTPUTF8		(1<<21)	/* RFC 6531 */
+#define SMTP_FEATURE_FROM_PROXY		(1<<22)	/* proxied connection */
+
+ /*
+  * Features that passivate under the endpoint.
+  */
+#define SMTP_FEATURE_ENDPOINT_MASK \
+	(~(SMTP_FEATURE_BEST_MX | SMTP_FEATURE_RSET_REJECTED \
+	| SMTP_FEATURE_FROM_CACHE))
+
+ /*
+  * Features that passivate under the logical destination.
+  */
+#define SMTP_FEATURE_DESTINATION_MASK (SMTP_FEATURE_BEST_MX)
+
+ /*
+  * Misc flags.
+  */
+#define SMTP_MISC_FLAG_LOOP_DETECT	(1<<0)
+#define	SMTP_MISC_FLAG_IN_STARTTLS	(1<<1)
+#define SMTP_MISC_FLAG_FIRST_NEXTHOP	(1<<2)
+#define SMTP_MISC_FLAG_FINAL_NEXTHOP	(1<<3)
+#define SMTP_MISC_FLAG_FINAL_SERVER	(1<<4)
+#define SMTP_MISC_FLAG_CONN_LOAD	(1<<5)
+#define SMTP_MISC_FLAG_CONN_STORE	(1<<6)
+#define SMTP_MISC_FLAG_COMPLETE_SESSION	(1<<7)
+#define SMTP_MISC_FLAG_PREF_IPV6	(1<<8)
+#define SMTP_MISC_FLAG_PREF_IPV4	(1<<9)
+
+#define SMTP_MISC_FLAG_CONN_CACHE_MASK \
+	(SMTP_MISC_FLAG_CONN_LOAD | SMTP_MISC_FLAG_CONN_STORE)
+
+ /*
+  * smtp.c
+  */
+#define SMTP_HAS_DSN(why)	(STR((why)->status)[0] != 0)
+#define SMTP_HAS_SOFT_DSN(why)	(STR((why)->status)[0] == '4')
+#define SMTP_HAS_HARD_DSN(why)	(STR((why)->status)[0] == '5')
+#define SMTP_HAS_LOOP_DSN(why) \
+    (SMTP_HAS_DSN(why) && strcmp(STR((why)->status) + 1, ".4.6") == 0)
+
+#define SMTP_SET_SOFT_DSN(why)	(STR((why)->status)[0] = '4')
+#define SMTP_SET_HARD_DSN(why)	(STR((why)->status)[0] = '5')
+
+extern int smtp_host_lookup_mask;	/* host lookup methods to use */
+
+#define SMTP_HOST_FLAG_DNS	(1<<0)
+#define SMTP_HOST_FLAG_NATIVE	(1<<1)
+
+extern int smtp_dns_support;		/* dns support level */
+
+#define SMTP_DNS_INVALID	(-1)	/* smtp_dns_support_level = <bogus> */
+#define SMTP_DNS_DISABLED	0	/* smtp_dns_support_level = disabled */
+#define SMTP_DNS_ENABLED	1	/* smtp_dns_support_level = enabled */
+#define SMTP_DNS_DNSSEC		2	/* smtp_dns_support_level = dnssec */
+
+extern SCACHE *smtp_scache;		/* connection cache instance */
+extern STRING_LIST *smtp_cache_dest;	/* cached destinations */
+
+extern MAPS *smtp_ehlo_dis_maps;	/* ehlo keyword filter */
+
+extern MAPS *smtp_pix_bug_maps;		/* PIX workarounds */
+
+extern MAPS *smtp_generic_maps;		/* make internal address valid */
+extern int smtp_ext_prop_mask;		/* address externsion propagation */
+extern unsigned smtp_dns_res_opt;	/* DNS query flags */
+
+#ifdef USE_TLS
+
+extern TLS_APPL_STATE *smtp_tls_ctx;	/* client-side TLS engine */
+extern int smtp_tls_insecure_mx_policy;	/* DANE post insecure MX? */
+
+#endif
+
+extern HBC_CHECKS *smtp_header_checks;	/* limited header checks */
+extern HBC_CHECKS *smtp_body_checks;	/* limited body checks */
+
+ /*
+  * smtp_session.c
+  */
+
+typedef struct SMTP_SESSION {
+    VSTREAM *stream;			/* network connection */
+    SMTP_ITERATOR *iterator;		/* dest, host, addr, port */
+    char   *namaddr;			/* mail exchanger */
+    char   *helo;			/* helo response */
+    unsigned port;			/* network byte order */
+    char   *namaddrport;		/* mail exchanger, incl. port */
+
+    VSTRING *buffer;			/* I/O buffer */
+    VSTRING *scratch;			/* scratch buffer */
+    VSTRING *scratch2;			/* scratch buffer */
+
+    int     features;			/* server features */
+    off_t   size_limit;			/* server limit or unknown */
+
+    ARGV   *history;			/* transaction log */
+    int     error_mask;			/* error classes */
+    struct MIME_STATE *mime_state;	/* mime state machine */
+
+    int     send_proto_helo;		/* XFORWARD support */
+
+    time_t  expire_time;		/* session reuse expiration time */
+    int     reuse_count;		/* # of times reused (for logging) */
+    int     forbidden;			/* No further I/O allowed */
+
+#ifdef USE_SASL_AUTH
+    char   *sasl_mechanism_list;	/* server mechanism list */
+    char   *sasl_username;		/* client username */
+    char   *sasl_passwd;		/* client password */
+    struct XSASL_CLIENT *sasl_client;	/* SASL internal state */
+    VSTRING *sasl_reply;		/* client response */
+#endif
+
+    /*
+     * TLS related state, don't forget to initialize in session_tls_init()!
+     */
+#ifdef USE_TLS
+    TLS_SESS_STATE *tls_context;	/* TLS library session state */
+    char   *tls_nexthop;		/* Nexthop domain for cert checks */
+    int     tls_retry_plain;		/* Try plain when TLS handshake fails */
+#endif
+
+    SMTP_STATE *state;			/* back link */
+} SMTP_SESSION;
+
+extern SMTP_SESSION *smtp_session_alloc(VSTREAM *, SMTP_ITERATOR *, time_t, int);
+extern void smtp_session_new_stream(SMTP_SESSION *, VSTREAM *, time_t, int);
+extern int smtp_sess_plaintext_ok(SMTP_ITERATOR *, int);
+extern void smtp_session_free(SMTP_SESSION *);
+extern int smtp_session_passivate(SMTP_SESSION *, VSTRING *, VSTRING *);
+extern SMTP_SESSION *smtp_session_activate(int, SMTP_ITERATOR *, VSTRING *, VSTRING *);
+
+ /*
+  * What's in a name?
+  */
+#define SMTP_HNAME(rr) (var_smtp_cname_overr ? (rr)->rname : (rr)->qname)
+
+ /*
+  * smtp_connect.c
+  */
+extern int smtp_connect(SMTP_STATE *);
+
+ /*
+  * smtp_proto.c
+  */
+extern void smtp_vrfy_init(void);
+extern int smtp_helo(SMTP_STATE *);
+extern int smtp_xfer(SMTP_STATE *);
+extern int smtp_rset(SMTP_STATE *);
+extern int smtp_quit(SMTP_STATE *);
+
+extern HBC_CALL_BACKS smtp_hbc_callbacks[];
+
+ /*
+  * A connection is re-usable if session->expire_time is > 0 and the
+  * expiration time has not been reached.  This is subtle because the timer
+  * can expire between sending a command and receiving the reply for that
+  * command.
+  * 
+  * But wait, there is more! When SMTP command pipelining is enabled, there are
+  * two protocol loops that execute at very different times: one loop that
+  * generates commands, and one loop that receives replies to those commands.
+  * These will be called "sender loop" and "receiver loop", respectively. At
+  * well-defined protocol synchronization points, the sender loop pauses to
+  * let the receiver loop catch up.
+  * 
+  * When we choose to reuse a connection, both the sender and receiver protocol
+  * loops end with "." (mail delivery) or "RSET" (address probe). When we
+  * choose not to reuse, both the sender and receiver protocol loops end with
+  * "QUIT". The problem is that we must make the same protocol choices in
+  * both the sender and receiver loops, even though those loops may execute
+  * at completely different times.
+  * 
+  * We "freeze" the choice in the sender loop, just before we generate "." or
+  * "RSET". The reader loop leaves the connection cacheable even if the timer
+  * expires by the time the response arrives. The connection cleanup code
+  * will call smtp_quit() for connections with an expired cache expiration
+  * timer.
+  * 
+  * We could have made the programmer's life a lot simpler by not making a
+  * choice at all, and always leaving it up to the connection cleanup code to
+  * call smtp_quit() for connections with an expired cache expiration timer.
+  * 
+  * As a general principle, neither the sender loop nor the receiver loop must
+  * modify the connection caching state, if that can affect the receiver
+  * state machine for not-yet processed replies to already-generated
+  * commands. This restriction does not apply when we have to exit the
+  * protocol loops prematurely due to e.g., timeout or connection loss, so
+  * that those pending replies will never be received.
+  * 
+  * But wait, there is even more! Only the first good connection for a specific
+  * destination may be cached under both the next-hop destination name and
+  * the server address; connections to alternate servers must be cached under
+  * the server address alone. This means we must distinguish between bad
+  * connections and other reasons why connections cannot be cached.
+  */
+#define THIS_SESSION_IS_CACHED \
+	(!THIS_SESSION_IS_FORBIDDEN && session->expire_time > 0)
+
+#define THIS_SESSION_IS_EXPIRED \
+	(THIS_SESSION_IS_CACHED \
+	    && (session->expire_time < vstream_ftime(session->stream) \
+		|| (var_smtp_reuse_count > 0 \
+		    && session->reuse_count >= var_smtp_reuse_count)))
+
+#define THIS_SESSION_IS_THROTTLED \
+	(!THIS_SESSION_IS_FORBIDDEN && session->expire_time < 0)
+
+#define THIS_SESSION_IS_FORBIDDEN \
+	(session->forbidden != 0)
+
+ /* Bring the bad news. */
+
+#define DONT_CACHE_THIS_SESSION \
+	(session->expire_time = 0)
+
+#define DONT_CACHE_THROTTLED_SESSION \
+	(session->expire_time = -1)
+
+#define DONT_USE_FORBIDDEN_SESSION \
+	(session->forbidden = 1)
+
+ /* Initialization. */
+
+#define USE_NEWBORN_SESSION \
+	(session->forbidden = 0)
+
+#define CACHE_THIS_SESSION_UNTIL(when) \
+	(session->expire_time = (when))
+
+ /*
+  * Encapsulate the following so that we don't expose details of of
+  * connection management and error handling to the SMTP protocol engine.
+  */
+#ifdef USE_SASL_AUTH
+#define HAVE_SASL_CREDENTIALS \
+	(var_smtp_sasl_enable \
+	     && *var_smtp_sasl_passwd \
+	     && smtp_sasl_passwd_lookup(session))
+#else
+#define HAVE_SASL_CREDENTIALS	(0)
+#endif
+
+#define PREACTIVE_DELAY \
+	(session->state->request->msg_stats.active_arrival.tv_sec - \
+	 session->state->request->msg_stats.incoming_arrival.tv_sec)
+
+#define TRACE_REQ_ONLY	(DEL_REQ_TRACE_ONLY(state->request->flags))
+
+#define PLAINTEXT_FALLBACK_OK_AFTER_STARTTLS_FAILURE \
+	(session->tls_context == 0 \
+	    && state->tls->level == TLS_LEV_MAY \
+	    && (TRACE_REQ_ONLY || PREACTIVE_DELAY >= var_min_backoff_time) \
+	    && !HAVE_SASL_CREDENTIALS)
+
+#define PLAINTEXT_FALLBACK_OK_AFTER_TLS_SESSION_FAILURE \
+	(session->tls_context != 0 \
+	    && SMTP_RCPT_LEFT(state) > SMTP_RCPT_MARK_COUNT(state) \
+	    && state->tls->level == TLS_LEV_MAY \
+	    && (TRACE_REQ_ONLY || PREACTIVE_DELAY >= var_min_backoff_time) \
+	    && !HAVE_SASL_CREDENTIALS)
+
+ /*
+  * XXX The following will not retry recipients that were deferred while the
+  * SMTP_MISC_FLAG_FINAL_SERVER flag was already set. This includes the case
+  * when TLS fails in the middle of a delivery.
+  */
+#define RETRY_AS_PLAINTEXT do { \
+	session->tls_retry_plain = 1; \
+	state->misc_flags &= ~SMTP_MISC_FLAG_FINAL_SERVER; \
+    } while (0)
+
+ /*
+  * smtp_chat.c
+  */
+typedef struct SMTP_RESP {		/* server response */
+    int     code;			/* SMTP code */
+    const char *dsn;			/* enhanced status */
+    char   *str;			/* full reply */
+    VSTRING *dsn_buf;			/* status buffer */
+    VSTRING *str_buf;			/* reply buffer */
+} SMTP_RESP;
+
+extern void PRINTFLIKE(2, 3) smtp_chat_cmd(SMTP_SESSION *, const char *,...);
+extern DICT *smtp_chat_resp_filter;
+extern SMTP_RESP *smtp_chat_resp(SMTP_SESSION *);
+extern void smtp_chat_init(SMTP_SESSION *);
+extern void smtp_chat_reset(SMTP_SESSION *);
+extern void smtp_chat_notify(SMTP_SESSION *);
+
+#define SMTP_RESP_FAKE(resp, _dsn) \
+    ((resp)->code = 0, \
+     (resp)->dsn = (_dsn), \
+     (resp)->str = DSN_BY_LOCAL_MTA, \
+     (resp))
+
+#define DSN_BY_LOCAL_MTA	((char *) 0)	/* DSN issued by local MTA */
+
+#define SMTP_RESP_SET_DSN(resp, _dsn) do { \
+	vstring_strcpy((resp)->dsn_buf, (_dsn)); \
+	(resp)->dsn = STR((resp)->dsn_buf); \
+    } while (0)
+
+ /*
+  * These operations implement a redundant mark-and-sweep algorithm that
+  * explicitly accounts for the fate of every recipient. The interface is
+  * documented in smtp_rcpt.c, which also implements the sweeping. The
+  * smtp_trouble.c module does most of the marking after failure.
+  * 
+  * When a delivery fails or succeeds, take one of the following actions:
+  * 
+  * - Mark the recipient as KEEP (deliver to alternate MTA) and do not update
+  * the delivery request status.
+  * 
+  * - Mark the recipient as DROP (remove from delivery request), log whether
+  * delivery succeeded or failed, delete the recipient from the queue file
+  * and/or update defer or bounce logfiles, and update the delivery request
+  * status.
+  * 
+  * At the end of a delivery attempt, all recipients must be marked one way or
+  * the other. Failure to do so will trigger a panic.
+  */
+#define SMTP_RCPT_STATE_KEEP	1	/* send to backup host */
+#define SMTP_RCPT_STATE_DROP	2	/* remove from request */
+#define SMTP_RCPT_INIT(state) do { \
+	    (state)->rcpt_drop = (state)->rcpt_keep = 0; \
+	    (state)->rcpt_left = state->request->rcpt_list.len; \
+	} while (0)
+
+#define SMTP_RCPT_DROP(state, rcpt) do { \
+	    (rcpt)->u.status = SMTP_RCPT_STATE_DROP; (state)->rcpt_drop++; \
+	} while (0)
+
+#define SMTP_RCPT_KEEP(state, rcpt) do { \
+	    (rcpt)->u.status = SMTP_RCPT_STATE_KEEP; (state)->rcpt_keep++; \
+	} while (0)
+
+#define SMTP_RCPT_ISMARKED(rcpt) ((rcpt)->u.status != 0)
+
+#define SMTP_RCPT_LEFT(state) (state)->rcpt_left
+
+#define SMTP_RCPT_MARK_COUNT(state) ((state)->rcpt_drop + (state)->rcpt_keep)
+
+extern void smtp_rcpt_cleanup(SMTP_STATE *);
+extern void smtp_rcpt_done(SMTP_STATE *, SMTP_RESP *, RECIPIENT *);
+
+ /*
+  * smtp_trouble.c
+  */
+#define SMTP_THROTTLE	1
+#define SMTP_NOTHROTTLE	0
+extern int smtp_sess_fail(SMTP_STATE *);
+extern int PRINTFLIKE(5, 6) smtp_misc_fail(SMTP_STATE *, int, const char *,
+				             SMTP_RESP *, const char *,...);
+extern void PRINTFLIKE(5, 6) smtp_rcpt_fail(SMTP_STATE *, RECIPIENT *,
+					          const char *, SMTP_RESP *,
+					            const char *,...);
+extern int smtp_stream_except(SMTP_STATE *, int, const char *);
+
+#define smtp_site_fail(state, mta, resp, ...) \
+	smtp_misc_fail((state), SMTP_THROTTLE, (mta), (resp), __VA_ARGS__)
+#define smtp_mesg_fail(state, mta, resp, ...) \
+	smtp_misc_fail((state), SMTP_NOTHROTTLE, (mta), (resp), __VA_ARGS__)
+
+ /*
+  * smtp_unalias.c
+  */
+extern const char *smtp_unalias_name(const char *);
+extern VSTRING *smtp_unalias_addr(VSTRING *, const char *);
+
+ /*
+  * smtp_state.c
+  */
+extern SMTP_STATE *smtp_state_alloc(void);
+extern void smtp_state_free(SMTP_STATE *);
+
+ /*
+  * smtp_map11.c
+  */
+extern int smtp_map11_external(VSTRING *, MAPS *, int);
+extern int smtp_map11_tree(TOK822 *, MAPS *, int);
+extern int smtp_map11_internal(VSTRING *, MAPS *, int);
+
+ /*
+  * smtp_key.c
+  */
+char   *smtp_key_prefix(VSTRING *, const char *, SMTP_ITERATOR *, int);
+
+#define SMTP_KEY_FLAG_SERVICE		(1<<0)	/* service name */
+#define SMTP_KEY_FLAG_SENDER		(1<<1)	/* sender address */
+#define SMTP_KEY_FLAG_REQ_NEXTHOP	(1<<2)	/* delivery request nexthop */
+#define SMTP_KEY_FLAG_CUR_NEXTHOP	(1<<3)	/* current nexthop */
+#define SMTP_KEY_FLAG_HOSTNAME		(1<<4)	/* remote host name */
+#define SMTP_KEY_FLAG_ADDR		(1<<5)	/* remote address */
+#define SMTP_KEY_FLAG_PORT		(1<<6)	/* remote port */
+#define SMTP_KEY_FLAG_TLS_LEVEL		(1<<7)	/* requested TLS level */
+
+#define SMTP_KEY_MASK_ALL \
+	(SMTP_KEY_FLAG_SERVICE | SMTP_KEY_FLAG_SENDER | \
+	SMTP_KEY_FLAG_REQ_NEXTHOP | \
+	SMTP_KEY_FLAG_CUR_NEXTHOP | SMTP_KEY_FLAG_HOSTNAME | \
+	SMTP_KEY_FLAG_ADDR | SMTP_KEY_FLAG_PORT | SMTP_KEY_FLAG_TLS_LEVEL)
+
+ /*
+  * Conditional lookup-key flags for cached connections that may be
+  * SASL-authenticated with a per-{sender, nexthop, or hostname} credential.
+  * Each bit corresponds to one type of smtp_sasl_password_file lookup key,
+  * and is turned on only when the corresponding main.cf parameter is turned
+  * on.
+  */
+#define COND_SASL_SMTP_KEY_FLAG_SENDER \
+	((var_smtp_sender_auth && *var_smtp_sasl_passwd) ? \
+	    SMTP_KEY_FLAG_SENDER : 0)
+
+#define COND_SASL_SMTP_KEY_FLAG_CUR_NEXTHOP \
+	(*var_smtp_sasl_passwd ? SMTP_KEY_FLAG_CUR_NEXTHOP : 0)
+
+#ifdef USE_TLS
+#define COND_TLS_SMTP_KEY_FLAG_CUR_NEXTHOP \
+	(TLS_MUST_MATCH(state->tls->level) ? SMTP_KEY_FLAG_CUR_NEXTHOP : 0)
+#else
+#define COND_TLS_SMTP_KEY_FLAG_CUR_NEXTHOP \
+	(0)
+#endif
+
+#define COND_SASL_SMTP_KEY_FLAG_HOSTNAME \
+	(*var_smtp_sasl_passwd ? SMTP_KEY_FLAG_HOSTNAME : 0)
+
+ /*
+  * Connection-cache destination lookup key, based on the delivery request
+  * nexthop. The SENDER attribute is a proxy for sender-dependent SASL
+  * credentials (or absence thereof), and prevents false connection sharing
+  * when different SASL credentials may be required for different deliveries
+  * to the same domain and port. Likewise, the delivery request nexthop
+  * (REQ_NEXTHOP) prevents false sharing of TLS identities (the destination
+  * key links only to appropriate endpoint lookup keys). The SERVICE
+  * attribute is a proxy for all request-independent configuration details.
+  */
+#define SMTP_KEY_MASK_SCACHE_DEST_LABEL \
+	(SMTP_KEY_FLAG_SERVICE | COND_SASL_SMTP_KEY_FLAG_SENDER \
+	| SMTP_KEY_FLAG_REQ_NEXTHOP)
+
+ /*
+  * Connection-cache endpoint lookup key. The SENDER, CUR_NEXTHOP, HOSTNAME,
+  * PORT and TLS_LEVEL attributes are proxies for SASL credentials and TLS
+  * authentication (or absence thereof), and prevent false connection sharing
+  * when different SASL credentials or TLS identities may be required for
+  * different deliveries to the same IP address and port. The SERVICE
+  * attribute is a proxy for all request-independent configuration details.
+  */
+#define SMTP_KEY_MASK_SCACHE_ENDP_LABEL \
+	(SMTP_KEY_FLAG_SERVICE | COND_SASL_SMTP_KEY_FLAG_SENDER \
+	| COND_SASL_SMTP_KEY_FLAG_CUR_NEXTHOP \
+	| COND_SASL_SMTP_KEY_FLAG_HOSTNAME \
+	| COND_TLS_SMTP_KEY_FLAG_CUR_NEXTHOP | SMTP_KEY_FLAG_ADDR | \
+	SMTP_KEY_FLAG_PORT | SMTP_KEY_FLAG_TLS_LEVEL)
+
+ /*
+  * Silly little macros.
+  */
+#define STR(s) vstring_str(s)
+#define LEN(s) VSTRING_LEN(s)
+
+extern int smtp_mode;
+
+#define VAR_LMTP_SMTP(x) (smtp_mode ? VAR_SMTP_##x : VAR_LMTP_##x)
+#define LMTP_SMTP_SUFFIX(x) (smtp_mode ? x##_SMTP : x##_LMTP)
+
+ /*
+  * Parsed command-line attributes. These do not change during the process
+  * lifetime.
+  */
+typedef struct {
+    int     flags;			/* from flags=, see below */
+} SMTP_CLI_ATTR;
+
+#define SMTP_CLI_FLAG_DELIVERED_TO	(1<<0)	/* prepend Delivered-To: */
+#define SMTP_CLI_FLAG_ORIG_RCPT		(1<<1)	/* prepend X-Original-To: */
+#define SMTP_CLI_FLAG_RETURN_PATH	(1<<2)	/* prepend Return-Path: */
+#define SMTP_CLI_FLAG_FINAL_DELIVERY	(1<<3)	/* final, not relay */
+
+#define SMTP_CLI_MASK_ADD_HEADERS	(SMTP_CLI_FLAG_DELIVERED_TO | \
+	SMTP_CLI_FLAG_ORIG_RCPT | SMTP_CLI_FLAG_RETURN_PATH)
+
+extern SMTP_CLI_ATTR smtp_cli_attr;
+
+ /*
+  * smtp_misc.c.
+  */
+extern void smtp_rewrite_generic_internal(VSTRING *, const char *);
+extern void smtp_quote_822_address_flags(VSTRING *, const char *, int);
+extern void smtp_quote_821_address(VSTRING *, const char *);
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	TLS support originally by:
+/*	Lutz Jaenicke
+/*	BTU Cottbus
+/*	Allgemeine Elektrotechnik
+/*	Universitaetsplatz 3-4
+/*	D-03044 Cottbus, Germany
+/*
+/*	Victor Duchovni
+/*	Morgan Stanley
+/*--*/
diff --git a/src/smtp/smtp_addr.c b/src/smtp/smtp_addr.c
new file mode 100644
index 0000000..2210ff7
--- /dev/null
+++ b/src/smtp/smtp_addr.c
@@ -0,0 +1,693 @@
+/*++
+/* NAME
+/*	smtp_addr 3
+/* SUMMARY
+/*	SMTP server address lookup
+/* SYNOPSIS
+/*	#include "smtp_addr.h"
+/*
+/*	DNS_RR *smtp_domain_addr(name, mxrr, misc_flags, why, found_myself)
+/*	char	*name;
+/*	DNS_RR  **mxrr;
+/*	int	misc_flags;
+/*	DSN_BUF	*why;
+/*	int	*found_myself;
+/*
+/*	DNS_RR *smtp_host_addr(name, misc_flags, why)
+/*	char	*name;
+/*	int	misc_flags;
+/*	DSN_BUF	*why;
+/* DESCRIPTION
+/*	This module implements Internet address lookups. By default,
+/*	lookups are done via the Internet domain name service (DNS).
+/*	A reasonable number of CNAME indirections is permitted. When
+/*	DNS lookups are disabled, host address lookup is done with
+/*	getnameinfo() or gethostbyname().
+/*
+/*	smtp_domain_addr() looks up the network addresses for mail
+/*	exchanger hosts listed for the named domain. Addresses are
+/*	returned in most-preferred first order. The result is truncated
+/*	so that it contains only hosts that are more preferred than the
+/*	local mail server itself. The found_myself result parameter
+/*	is updated when the local MTA is MX host for the specified
+/*	destination.  If MX records were found, the rname, qname,
+/*	and dnssec validation status of the MX RRset are returned
+/*	via mxrr, which the caller must free with dns_rr_free().
+/*
+/*	When no mail exchanger is listed in the DNS for \fIname\fR, the
+/*	request is passed to smtp_host_addr().
+/*
+/*	It is an error to call smtp_domain_addr() when DNS lookups are
+/*	disabled.
+/*
+/*	smtp_host_addr() looks up all addresses listed for the named
+/*	host.  The host can be specified as a numerical Internet network
+/*	address, or as a symbolic host name.
+/*
+/*	Results from smtp_domain_addr() or smtp_host_addr() are
+/*	destroyed by dns_rr_free(), including null lists.
+/* DIAGNOSTICS
+/*	Panics: interface violations. For example, calling smtp_domain_addr()
+/*	when DNS lookups are explicitly disabled.
+/*
+/*	All routines either return a DNS_RR pointer, or return a null
+/*	pointer and update the \fIwhy\fR argument accordingly.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <netdb.h>
+#include <ctype.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <mymalloc.h>
+#include <inet_addr_list.h>
+#include <stringops.h>
+#include <myaddrinfo.h>
+#include <inet_proto.h>
+#include <midna_domain.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <own_inet_addr.h>
+#include <dsn_buf.h>
+
+/* DNS library. */
+
+#include <dns.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_addr.h"
+
+/* smtp_print_addr - print address list */
+
+static void smtp_print_addr(const char *what, DNS_RR *addr_list)
+{
+    DNS_RR *addr;
+    MAI_HOSTADDR_STR hostaddr;
+
+    msg_info("begin %s address list", what);
+    for (addr = addr_list; addr; addr = addr->next) {
+	if (dns_rr_to_pa(addr, &hostaddr) == 0) {
+	    msg_warn("skipping record type %s: %m", dns_strtype(addr->type));
+	} else {
+	    msg_info("pref %4d host %s/%s",
+		     addr->pref, SMTP_HNAME(addr),
+		     hostaddr.buf);
+	}
+    }
+    msg_info("end %s address list", what);
+}
+
+/* smtp_addr_one - address lookup for one host name */
+
+static DNS_RR *smtp_addr_one(DNS_RR *addr_list, const char *host, int res_opt,
+			             unsigned pref, DSN_BUF *why)
+{
+    const char *myname = "smtp_addr_one";
+    DNS_RR *addr = 0;
+    DNS_RR *rr;
+    int     aierr;
+    struct addrinfo *res0;
+    struct addrinfo *res;
+    INET_PROTO_INFO *proto_info = inet_proto_info();
+    unsigned char *proto_family_list = proto_info->sa_family_list;
+    int     found;
+
+    if (msg_verbose)
+	msg_info("%s: host %s", myname, host);
+
+    /*
+     * Interpret a numerical name as an address.
+     */
+    if (hostaddr_to_sockaddr(host, (char *) 0, 0, &res0) == 0) {
+	if (strchr((char *) proto_family_list, res0->ai_family) != 0) {
+	    if ((addr = dns_sa_to_rr(host, pref, res0->ai_addr)) == 0)
+		msg_fatal("host %s: conversion error for address family "
+			  "%d: %m", host, res0->ai_addr->sa_family);
+	    addr_list = dns_rr_append(addr_list, addr);
+	    freeaddrinfo(res0);
+	    return (addr_list);
+	}
+	freeaddrinfo(res0);
+    }
+
+    /*
+     * Use DNS lookup, but keep the option open to use native name service.
+     * 
+     * XXX A soft error dominates past and future hard errors. Therefore we
+     * should not clobber a soft error text and status code.
+     */
+    if (smtp_host_lookup_mask & SMTP_HOST_FLAG_DNS) {
+	res_opt |= smtp_dns_res_opt;
+	switch (dns_lookup_v(host, res_opt, &addr, (VSTRING *) 0,
+			     why->reason, DNS_REQ_FLAG_NONE,
+			     proto_info->dns_atype_list)) {
+	case DNS_OK:
+	    for (rr = addr; rr; rr = rr->next)
+		rr->pref = pref;
+	    addr_list = dns_rr_append(addr_list, addr);
+	    return (addr_list);
+	default:
+	    dsb_status(why, "4.4.3");
+	    return (addr_list);
+	case DNS_FAIL:
+	    dsb_status(why, SMTP_HAS_SOFT_DSN(why) ? "4.4.3" : "5.4.3");
+	    return (addr_list);
+	case DNS_INVAL:
+	    dsb_status(why, SMTP_HAS_SOFT_DSN(why) ? "4.4.4" : "5.4.4");
+	    return (addr_list);
+	case DNS_POLICY:
+	    dsb_status(why, "4.7.0");
+	    return (addr_list);
+	case DNS_NOTFOUND:
+	    dsb_status(why, SMTP_HAS_SOFT_DSN(why) ? "4.4.4" : "5.4.4");
+	    /* maybe native naming service will succeed */
+	    break;
+	}
+    }
+
+    /*
+     * Use the native name service which also looks in /etc/hosts.
+     * 
+     * XXX A soft error dominates past and future hard errors. Therefore we
+     * should not clobber a soft error text and status code.
+     */
+#define RETRY_AI_ERROR(e) \
+        ((e) == EAI_AGAIN || (e) == EAI_MEMORY || (e) == EAI_SYSTEM)
+#ifdef EAI_NODATA
+#define DSN_NOHOST(e) \
+	((e) == EAI_AGAIN || (e) == EAI_NODATA || (e) == EAI_NONAME)
+#else
+#define DSN_NOHOST(e) \
+	((e) == EAI_AGAIN || (e) == EAI_NONAME)
+#endif
+
+    if (smtp_host_lookup_mask & SMTP_HOST_FLAG_NATIVE) {
+	if ((aierr = hostname_to_sockaddr(host, (char *) 0, 0, &res0)) != 0) {
+	    dsb_simple(why, (SMTP_HAS_SOFT_DSN(why) || RETRY_AI_ERROR(aierr)) ?
+		       (DSN_NOHOST(aierr) ? "4.4.4" : "4.3.0") :
+		       (DSN_NOHOST(aierr) ? "5.4.4" : "5.3.0"),
+		       "unable to look up host %s: %s",
+		       host, MAI_STRERROR(aierr));
+	} else {
+	    for (found = 0, res = res0; res != 0; res = res->ai_next) {
+		if (strchr((char *) proto_family_list, res->ai_family) == 0) {
+		    msg_info("skipping address family %d for host %s",
+			     res->ai_family, host);
+		    continue;
+		}
+		found++;
+		if ((addr = dns_sa_to_rr(host, pref, res->ai_addr)) == 0)
+		    msg_fatal("host %s: conversion error for address family "
+			      "%d: %m", host, res0->ai_addr->sa_family);
+		addr_list = dns_rr_append(addr_list, addr);
+	    }
+	    freeaddrinfo(res0);
+	    if (found == 0) {
+		dsb_simple(why, SMTP_HAS_SOFT_DSN(why) ? "4.4.4" : "5.4.4",
+			   "%s: host not found", host);
+	    }
+	    return (addr_list);
+	}
+    }
+
+    /*
+     * No further alternatives for host lookup.
+     */
+    return (addr_list);
+}
+
+/* smtp_addr_list - address lookup for a list of mail exchangers */
+
+static DNS_RR *smtp_addr_list(DNS_RR *mx_names, DSN_BUF *why)
+{
+    DNS_RR *addr_list = 0;
+    DNS_RR *rr;
+    int     res_opt = 0;
+
+    if (mx_names->dnssec_valid)
+	res_opt = RES_USE_DNSSEC;
+#ifdef USE_TLS
+    else if (smtp_tls_insecure_mx_policy > TLS_LEV_MAY)
+	res_opt = RES_USE_DNSSEC;
+#endif
+
+    /*
+     * As long as we are able to look up any host address, we ignore problems
+     * with DNS lookups (except if we're backup MX, and all the better MX
+     * hosts can't be found).
+     * 
+     * XXX 2821: update the error status (0->FAIL upon unrecoverable lookup
+     * error, any->RETRY upon temporary lookup error) so that we can
+     * correctly handle the case of no resolvable MX host. Currently this is
+     * always treated as a soft error. RFC 2821 wants a more precise
+     * response.
+     * 
+     * XXX dns_lookup() enables RES_DEFNAMES. This is wrong for names found in
+     * MX records - we should not append the local domain to dot-less names.
+     * 
+     * XXX However, this is not the only problem. If we use the native name
+     * service for host lookup, then it will usually enable RES_DNSRCH which
+     * appends local domain information to all lookups. In particular,
+     * getaddrinfo() may invoke a resolver that runs in a different process
+     * (NIS server, nscd), so we can't even reliably turn this off by
+     * tweaking the in-process resolver flags.
+     */
+    for (rr = mx_names; rr; rr = rr->next) {
+	if (rr->type != T_MX)
+	    msg_panic("smtp_addr_list: bad resource type: %d", rr->type);
+	addr_list = smtp_addr_one(addr_list, (char *) rr->data, res_opt,
+				  rr->pref, why);
+    }
+    return (addr_list);
+}
+
+/* smtp_find_self - spot myself in a crowd of mail exchangers */
+
+static DNS_RR *smtp_find_self(DNS_RR *addr_list)
+{
+    const char *myname = "smtp_find_self";
+    INET_ADDR_LIST *self;
+    INET_ADDR_LIST *proxy;
+    DNS_RR *addr;
+    int     i;
+
+    self = own_inet_addr_list();
+    proxy = proxy_inet_addr_list();
+
+    for (addr = addr_list; addr; addr = addr->next) {
+
+	/*
+	 * Find out if this mail system is listening on this address.
+	 */
+	for (i = 0; i < self->used; i++)
+	    if (DNS_RR_EQ_SA(addr, (struct sockaddr *) (self->addrs + i))) {
+		if (msg_verbose)
+		    msg_info("%s: found self at pref %d", myname, addr->pref);
+		return (addr);
+	    }
+
+	/*
+	 * Find out if this mail system has a proxy listening on this
+	 * address.
+	 */
+	for (i = 0; i < proxy->used; i++)
+	    if (DNS_RR_EQ_SA(addr, (struct sockaddr *) (proxy->addrs + i))) {
+		if (msg_verbose)
+		    msg_info("%s: found proxy at pref %d", myname, addr->pref);
+		return (addr);
+	    }
+    }
+
+    /*
+     * Didn't find myself, or my proxy.
+     */
+    if (msg_verbose)
+	msg_info("%s: not found", myname);
+    return (0);
+}
+
+/* smtp_truncate_self - truncate address list at self and equivalents */
+
+static DNS_RR *smtp_truncate_self(DNS_RR *addr_list, unsigned pref)
+{
+    DNS_RR *addr;
+    DNS_RR *last;
+
+    for (last = 0, addr = addr_list; addr; last = addr, addr = addr->next) {
+	if (pref == addr->pref) {
+	    if (msg_verbose)
+		smtp_print_addr("truncated", addr);
+	    dns_rr_free(addr);
+	    if (last == 0) {
+		addr_list = 0;
+	    } else {
+		last->next = 0;
+	    }
+	    break;
+	}
+    }
+    return (addr_list);
+}
+
+/* smtp_balance_inet_proto - balance IPv4/6 protocols within address limit */
+
+static DNS_RR *smtp_balance_inet_proto(DNS_RR *addr_list, int misc_flags,
+				               int addr_limit)
+{
+    const char myname[] = "smtp_balance_inet_proto";
+    DNS_RR *rr;
+    DNS_RR *stripped_list;
+    DNS_RR *next;
+    int     v6_count;
+    int     v4_count;
+    int     v6_target,
+            v4_target;
+    int    *p;
+
+    /*
+     * Precondition: the input is sorted by MX preference (not necessarily IP
+     * address family preference), and addresses with the same or worse
+     * preference than 'myself' have been eliminated. Postcondition: the
+     * relative list order is unchanged, but some elements are removed.
+     */
+
+    /*
+     * Count the number of IPv6 and IPv4 addresses.
+     */
+    for (v4_count = v6_count = 0, rr = addr_list; rr != 0; rr = rr->next) {
+	if (rr->type == T_A) {
+	    v4_count++;
+	} else if (rr->type == T_AAAA) {
+	    v6_count++;
+	} else {
+	    msg_panic("%s: unexpected record type: %s",
+		      myname, dns_strtype(rr->type));
+	}
+    }
+
+    /*
+     * Ensure that one address type will not out-crowd the other, while
+     * enforcing the address count limit. This works around a current problem
+     * where some destination announces primarily IPv6 MX addresses, the
+     * smtp_address_limit eliminates most or all IPv4 addresses, and the
+     * destination is not reachable over IPv6.
+     * 
+     * Maybe: do all smtp_mx_address_limit enforcement here, and remove
+     * pre-existing enforcement elsewhere. That would obsolete the
+     * smtp_balance_inet_protocols configuration parameter.
+     */
+    if (v4_count > 0 && v6_count > 0 && v4_count + v6_count > addr_limit) {
+
+	/*-
+         * Decide how many IPv6 and IPv4 addresses to keep. The code below
+         * has three branches, corresponding to the regions R1, R2 and R3
+         * in the figure.
+         *
+         *  L = addr_limit
+         *  X = excluded by condition (v4_count + v6_count > addr_limit)
+         *
+         * v4_count
+         *     ^
+         *     |
+         *  L  \  R1
+         *     |X\     |
+         *     |XXX\   |
+         *     |XXXXX\ | R2
+         * L/2 +-------\-------
+         *     |XXXXXXX|X\
+         *     |XXXXXXX|XXX\  R3
+         *     |XXXXXXX|XXXXX\
+         *   0 +-------+-------\--> v6_count
+         *     0      L/2      L
+         */
+	if (v6_count <= addr_limit / 2) {	/* Region R1 */
+	    v6_target = v6_count;
+	    v4_target = addr_limit - v6_target;
+	} else if (v4_count <= addr_limit / 2) {/* Region R3 */
+	    v4_target = v4_count;
+	    v6_target = addr_limit - v4_target;
+	} else {				/* Region R2 */
+	    /* v4_count > addr_limit / 2 && v6_count > addr_limit / 2 */
+	    v4_target = (addr_limit + (addr_list->type == T_A)) / 2;
+	    v6_target = addr_limit - v4_target;
+	}
+	if (msg_verbose)
+	    msg_info("v6_target=%d, v4_target=%d", v6_target, v4_target);
+
+	/* Enforce the address count targets. */
+	stripped_list = 0;
+	for (rr = addr_list; rr != 0; rr = next) {
+	    next = rr->next;
+	    rr->next = 0;
+	    if (rr->type == T_A) {
+		p = &v4_target;
+	    } else if (rr->type == T_AAAA) {
+		p = &v6_target;
+	    } else {
+		msg_panic("%s: unexpected record type: %s",
+			  myname, dns_strtype(rr->type));
+	    }
+	    if (*p > 0) {
+		stripped_list = dns_rr_append(stripped_list, rr);
+		*p -= 1;
+	    } else {
+		dns_rr_free(rr);
+	    }
+	}
+	if (v4_target > 0 || v6_target > 0)
+	    msg_panic("%s: bad target count: v4_target=%d, v6_target=%d",
+		      myname, v4_target, v6_target);
+	if (msg_verbose)
+	    smtp_print_addr("smtp_balance_inet_proto result", stripped_list);
+	return (stripped_list);
+    } else {
+	return (addr_list);
+    }
+}
+
+/* smtp_domain_addr - mail exchanger address lookup */
+
+DNS_RR *smtp_domain_addr(const char *name, DNS_RR **mxrr, int misc_flags,
+			         DSN_BUF *why, int *found_myself)
+{
+    DNS_RR *mx_names;
+    DNS_RR *addr_list = 0;
+    DNS_RR *self = 0;
+    unsigned best_pref;
+    unsigned best_found;
+    int     r = 0;			/* Resolver flags */
+    const char *aname;
+
+    dsb_reset(why);				/* Paranoia */
+
+    /*
+     * Preferences from DNS use 0..32767, fall-backs use 32768+.
+     */
+#define IMPOSSIBLE_PREFERENCE	(~0)
+
+    /*
+     * Sanity check.
+     */
+    if (smtp_dns_support == SMTP_DNS_DISABLED)
+	msg_panic("smtp_domain_addr: DNS lookup is disabled");
+    if (smtp_dns_support == SMTP_DNS_DNSSEC)
+	r |= RES_USE_DNSSEC;
+
+    /*
+     * IDNA support.
+     */
+#ifndef NO_EAI
+    if (!allascii(name) && (aname = midna_domain_to_ascii(name)) != 0) {
+	if (msg_verbose)
+	    msg_info("%s asciified to %s", name, aname);
+    } else
+#endif
+	aname = name;
+
+    /*
+     * Look up the mail exchanger hosts listed for this name. Sort the
+     * results by preference. Look up the corresponding host addresses, and
+     * truncate the list so that it contains only hosts that are more
+     * preferred than myself. When no MX resource records exist, look up the
+     * addresses listed for this name.
+     * 
+     * According to RFC 974: "It is possible that the list of MXs in the
+     * response to the query will be empty.  This is a special case.  If the
+     * list is empty, mailers should treat it as if it contained one RR, an
+     * MX RR with a preference value of 0, and a host name of REMOTE.  (I.e.,
+     * REMOTE is its only MX).  In addition, the mailer should do no further
+     * processing on the list, but should attempt to deliver the message to
+     * REMOTE."
+     * 
+     * Normally it is OK if an MX host cannot be found in the DNS; we'll just
+     * use a backup one, and silently ignore the better MX host. However, if
+     * the best backup that we can find in the DNS is the local machine, then
+     * we must remember that the local machine is not the primary MX host, or
+     * else we will claim that mail loops back.
+     * 
+     * XXX Optionally do A lookups even when the MX lookup didn't complete.
+     * Unfortunately with some DNS servers this is not a transient problem.
+     * 
+     * XXX Ideally we would perform A lookups only as far as needed. But as long
+     * as we're looking up all the hosts, it would be better to look up the
+     * least preferred host first, so that DNS lookup error messages make
+     * more sense.
+     * 
+     * XXX 2821: RFC 2821 says that the sender must shuffle equal-preference MX
+     * hosts, whereas multiple A records per hostname must be used in the
+     * order as received. They make the bogus assumption that a hostname with
+     * multiple A records corresponds to one machine with multiple network
+     * interfaces.
+     * 
+     * XXX 2821: Postfix recognizes the local machine by looking for its own IP
+     * address in the list of mail exchangers. RFC 2821 says one has to look
+     * at the mail exchanger hostname as well, making the bogus assumption
+     * that an IP address is listed only under one hostname. However, looking
+     * at hostnames provides a partial solution for MX hosts behind a NAT
+     * gateway.
+     */
+    switch (dns_lookup(aname, T_MX, r, &mx_names, (VSTRING *) 0, why->reason)) {
+    default:
+	dsb_status(why, "4.4.3");
+	if (var_ign_mx_lookup_err)
+	    addr_list = smtp_host_addr(aname, misc_flags, why);
+	break;
+    case DNS_INVAL:
+	dsb_status(why, "5.4.4");
+	if (var_ign_mx_lookup_err)
+	    addr_list = smtp_host_addr(aname, misc_flags, why);
+	break;
+    case DNS_NULLMX:
+	dsb_status(why, "5.1.0");
+	break;
+    case DNS_POLICY:
+	dsb_status(why, "4.7.0");
+	break;
+    case DNS_FAIL:
+	dsb_status(why, "5.4.3");
+	if (var_ign_mx_lookup_err)
+	    addr_list = smtp_host_addr(aname, misc_flags, why);
+	break;
+    case DNS_OK:
+	mx_names = dns_rr_sort(mx_names, dns_rr_compare_pref_any);
+	best_pref = (mx_names ? mx_names->pref : IMPOSSIBLE_PREFERENCE);
+	addr_list = smtp_addr_list(mx_names, why);
+	if (mxrr)
+	    *mxrr = dns_rr_copy(mx_names);	/* copies one record! */
+	dns_rr_free(mx_names);
+	if (addr_list == 0) {
+	    /* Text does not change. */
+	    if (var_smtp_defer_mxaddr) {
+		/* Don't clobber the null terminator. */
+		if (SMTP_HAS_HARD_DSN(why))
+		    SMTP_SET_SOFT_DSN(why);	/* XXX */
+		/* Require some error status. */
+		else if (!SMTP_HAS_SOFT_DSN(why))
+		    msg_panic("smtp_domain_addr: bad status");
+	    }
+	    msg_warn("no MX host for %s has a valid address record", name);
+	    break;
+	}
+	best_found = (addr_list ? addr_list->pref : IMPOSSIBLE_PREFERENCE);
+	if (msg_verbose)
+	    smtp_print_addr(name, addr_list);
+	if ((misc_flags & SMTP_MISC_FLAG_LOOP_DETECT)
+	    && (self = smtp_find_self(addr_list)) != 0) {
+	    addr_list = smtp_truncate_self(addr_list, self->pref);
+	    if (addr_list == 0) {
+		if (best_pref != best_found) {
+		    dsb_simple(why, "4.4.4",
+			       "unable to find primary relay for %s", name);
+		} else {
+		    dsb_simple(why, "5.4.6", "mail for %s loops back to myself",
+			       name);
+		}
+	    }
+	}
+#define SMTP_COMPARE_ADDR(flags) \
+	(((flags) & SMTP_MISC_FLAG_PREF_IPV6) ? dns_rr_compare_pref_ipv6 : \
+	 ((flags) & SMTP_MISC_FLAG_PREF_IPV4) ? dns_rr_compare_pref_ipv4 : \
+	 dns_rr_compare_pref_any)
+
+	if (addr_list && addr_list->next) {
+	    if (var_smtp_rand_addr)
+		addr_list = dns_rr_shuffle(addr_list);
+	    addr_list = dns_rr_sort(addr_list, SMTP_COMPARE_ADDR(misc_flags));
+	    if (var_smtp_mxaddr_limit > 0 && var_smtp_balance_inet_proto)
+		addr_list = smtp_balance_inet_proto(addr_list, misc_flags,
+						    var_smtp_mxaddr_limit);
+	}
+	break;
+    case DNS_NOTFOUND:
+	addr_list = smtp_host_addr(aname, misc_flags, why);
+	break;
+    }
+
+    /*
+     * Clean up.
+     */
+    *found_myself |= (self != 0);
+    return (addr_list);
+}
+
+/* smtp_host_addr - direct host lookup */
+
+DNS_RR *smtp_host_addr(const char *host, int misc_flags, DSN_BUF *why)
+{
+    DNS_RR *addr_list;
+    int     res_opt = 0;
+    const char *ahost;
+
+    dsb_reset(why);				/* Paranoia */
+
+    if (smtp_dns_support == SMTP_DNS_DNSSEC)
+	res_opt |= RES_USE_DNSSEC;
+
+    /*
+     * IDNA support.
+     */
+#ifndef NO_EAI
+    if (!allascii(host) && (ahost = midna_domain_to_ascii(host)) != 0) {
+	if (msg_verbose)
+	    msg_info("%s asciified to %s", host, ahost);
+    } else
+#endif
+	ahost = host;
+
+    /*
+     * If the host is specified by numerical address, just convert the
+     * address to internal form. Otherwise, the host is specified by name.
+     */
+#define PREF0	0
+    addr_list = smtp_addr_one((DNS_RR *) 0, ahost, res_opt, PREF0, why);
+    if (addr_list
+	&& (misc_flags & SMTP_MISC_FLAG_LOOP_DETECT)
+	&& smtp_find_self(addr_list) != 0) {
+	dns_rr_free(addr_list);
+	dsb_simple(why, "5.4.6", "mail for %s loops back to myself", host);
+	return (0);
+    }
+    if (addr_list && addr_list->next) {
+	if (var_smtp_rand_addr)
+	    addr_list = dns_rr_shuffle(addr_list);
+	/* The following changes the order of equal-preference hosts. */
+	if (inet_proto_info()->ai_family_list[1] != 0)
+	    addr_list = dns_rr_sort(addr_list, SMTP_COMPARE_ADDR(misc_flags));
+	if (var_smtp_mxaddr_limit > 0 && var_smtp_balance_inet_proto)
+	    addr_list = smtp_balance_inet_proto(addr_list, misc_flags,
+						var_smtp_mxaddr_limit);
+    }
+    if (msg_verbose)
+	smtp_print_addr(host, addr_list);
+    return (addr_list);
+}
diff --git a/src/smtp/smtp_addr.h b/src/smtp/smtp_addr.h
new file mode 100644
index 0000000..8f20961
--- /dev/null
+++ b/src/smtp/smtp_addr.h
@@ -0,0 +1,31 @@
+/*++
+/* NAME
+/*	smtp_addr 3h
+/* SUMMARY
+/*	SMTP server address lookup
+/* SYNOPSIS
+/*	#include "smtp_addr.h"
+/* DESCRIPTION
+/* .nf
+
+ /*
+  * DNS library.
+  */
+#include <dns.h>
+
+ /*
+  * Internal interfaces.
+  */
+extern DNS_RR *smtp_host_addr(const char *, int, DSN_BUF *);
+extern DNS_RR *smtp_domain_addr(const char *, DNS_RR **, int, DSN_BUF *, int *);
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
diff --git a/src/smtp/smtp_chat.c b/src/smtp/smtp_chat.c
new file mode 100644
index 0000000..bff5986
--- /dev/null
+++ b/src/smtp/smtp_chat.c
@@ -0,0 +1,496 @@
+/*++
+/* NAME
+/*	smtp_chat 3
+/* SUMMARY
+/*	SMTP client request/response support
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	typedef struct {
+/* .in +4
+/*		int code;	/* SMTP code, not sanitized */
+/*		char *dsn;	/* enhanced status, sanitized */
+/*		char *str;	/* unmodified SMTP reply */
+/*		VSTRING *dsn_buf;
+/*		VSTRING *str_buf;
+/* .in -4
+/*	} SMTP_RESP;
+/*
+/*	void	smtp_chat_cmd(session, format, ...)
+/*	SMTP_SESSION *session;
+/*	const char *format;
+/*
+/*	DICT	*smtp_chat_resp_filter;
+/*
+/*	SMTP_RESP *smtp_chat_resp(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_chat_notify(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_chat_init(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_chat_reset(session)
+/*	SMTP_SESSION *session;
+/* DESCRIPTION
+/*	This module implements SMTP client support for request/reply
+/*	conversations, and maintains a limited SMTP transaction log.
+/*
+/*	smtp_chat_cmd() formats a command and sends it to an SMTP server.
+/*	Optionally, the command is logged.
+/*
+/*	smtp_chat_resp() reads one SMTP server response. It extracts
+/*	the SMTP reply code and enhanced status code from the text,
+/*	and concatenates multi-line responses to one string, using
+/*	a newline as separator.  Optionally, the server response
+/*	is logged.
+/* .IP \(bu
+/*	Postfix never sanitizes the extracted SMTP reply code except
+/*	to ensure that it is a three-digit code. A malformed reply
+/*	results in a null extracted SMTP reply code value.
+/* .IP \(bu
+/*	Postfix always sanitizes the extracted enhanced status code.
+/*	When the server's SMTP status code is 2xx, 4xx or 5xx,
+/*	Postfix requires that the first digit of the server's
+/*	enhanced status code matches the first digit of the server's
+/*	SMTP status code.  In case of a mis-match, or when the
+/*	server specified no status code, the extracted enhanced
+/*	status code is set to 2.0.0, 4.0.0 or 5.0.0 instead.  With
+/*	SMTP reply codes other than 2xx, 4xx or 5xx, the extracted
+/*	enhanced status code is set to a default value of 5.5.0
+/*	(protocol error) for reasons outlined under the next bullet.
+/* .IP \(bu
+/*	Since the SMTP reply code may violate the protocol even
+/*	when it is correctly formatted, Postfix uses the sanitized
+/*	extracted enhanced status code to decide whether an error
+/*	condition is permanent or transient.  This means that the
+/*	caller may have to update the enhanced status code when it
+/*	discovers that a server reply violates the SMTP protocol,
+/*	even though it was correctly formatted. This happens when
+/*	the client and server get out of step due to a broken proxy
+/*	agent.
+/* .PP
+/*	smtp_chat_resp_filter specifies an optional filter to
+/*	transform one server reply line before it is parsed. The
+/*	filter is invoked once for each line of a multi-line reply.
+/*
+/*	smtp_chat_notify() sends a copy of the SMTP transaction log
+/*	to the postmaster for review. The postmaster notice is sent only
+/*	when delivery is possible immediately. It is an error to call
+/*	smtp_chat_notify() when no SMTP transaction log exists.
+/*
+/*	smtp_chat_init() initializes the per-session transaction log.
+/*	This must be done at the beginning of a new SMTP session.
+/*
+/*	smtp_chat_reset() resets the transaction log. This is
+/*	typically done at the beginning or end of an SMTP session,
+/*	or within a session to discard non-error information.
+/* DIAGNOSTICS
+/*	Fatal errors: memory allocation problem, server response exceeds
+/*	configurable limit.
+/*	All other exceptions are handled by long jumps (see smtp_stream(3)).
+/* SEE ALSO
+/*	smtp_stream(3) SMTP session I/O support
+/*	msg(3) generic logging interface
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <stdlib.h>			/* 44BSD stdarg.h uses abort() */
+#include <stdarg.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <string.h>
+#include <limits.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <argv.h>
+#include <stringops.h>
+#include <line_wrap.h>
+#include <mymalloc.h>
+
+/* Global library. */
+
+#include <recipient_list.h>
+#include <deliver_request.h>
+#include <smtp_stream.h>
+#include <mail_params.h>
+#include <mail_addr.h>
+#include <post_mail.h>
+#include <mail_error.h>
+#include <dsn_util.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+
+ /*
+  * Server reply transformations.
+  */
+DICT   *smtp_chat_resp_filter;
+
+/* smtp_chat_init - initialize SMTP transaction log */
+
+void    smtp_chat_init(SMTP_SESSION *session)
+{
+    session->history = 0;
+}
+
+/* smtp_chat_reset - reset SMTP transaction log */
+
+void    smtp_chat_reset(SMTP_SESSION *session)
+{
+    if (session->history) {
+	argv_free(session->history);
+	session->history = 0;
+    }
+}
+
+/* smtp_chat_append - append record to SMTP transaction log */
+
+static void smtp_chat_append(SMTP_SESSION *session, const char *direction,
+			             const char *data)
+{
+    char   *line;
+
+    if (session->history == 0)
+	session->history = argv_alloc(10);
+    line = concatenate(direction, data, (char *) 0);
+    argv_add(session->history, line, (char *) 0);
+    myfree(line);
+}
+
+/* smtp_chat_cmd - send an SMTP command */
+
+void    smtp_chat_cmd(SMTP_SESSION *session, const char *fmt,...)
+{
+    va_list ap;
+
+    /*
+     * Format the command, and update the transaction log.
+     */
+    va_start(ap, fmt);
+    vstring_vsprintf(session->buffer, fmt, ap);
+    va_end(ap);
+    smtp_chat_append(session, "Out: ", STR(session->buffer));
+
+    /*
+     * Optionally log the command first, so we can see in the log what the
+     * program is trying to do.
+     */
+    if (msg_verbose)
+	msg_info("> %s: %s", session->namaddrport, STR(session->buffer));
+
+    /*
+     * Send the command to the SMTP server.
+     */
+    smtp_fputs(STR(session->buffer), LEN(session->buffer), session->stream);
+
+    /*
+     * Force flushing of output does not belong here. It is done in the
+     * smtp_loop() main protocol loop when reading the server response, and
+     * in smtp_helo() when reading the EHLO response after sending the EHLO
+     * command.
+     * 
+     * If we do forced flush here, then we must longjmp() on error, and a
+     * matching "prepare for disaster" error handler must be set up before
+     * every smtp_chat_cmd() call.
+     */
+#if 0
+
+    /*
+     * Flush unsent data to avoid timeouts after slow DNS lookups.
+     */
+    if (time((time_t *) 0) - vstream_ftime(session->stream) > 10)
+	vstream_fflush(session->stream);
+
+    /*
+     * Abort immediately if the connection is broken.
+     */
+    if (vstream_ftimeout(session->stream))
+	vstream_longjmp(session->stream, SMTP_ERR_TIME);
+    if (vstream_ferror(session->stream))
+	vstream_longjmp(session->stream, SMTP_ERR_EOF);
+#endif
+}
+
+/* smtp_chat_resp - read and process SMTP server response */
+
+SMTP_RESP *smtp_chat_resp(SMTP_SESSION *session)
+{
+    static SMTP_RESP rdata;
+    char   *cp;
+    int     last_char;
+    int     three_digs = 0;
+    size_t  len;
+    const char *new_reply;
+    int     chat_append_flag;
+    int     chat_append_skipped = 0;
+
+    /*
+     * Initialize the response data buffer.
+     */
+    if (rdata.str_buf == 0) {
+	rdata.dsn_buf = vstring_alloc(10);
+	rdata.str_buf = vstring_alloc(100);
+    }
+
+    /*
+     * Censor out non-printable characters in server responses. Concatenate
+     * multi-line server responses. Separate the status code from the text.
+     * Leave further parsing up to the application.
+     * 
+     * We can't parse or store input that exceeds var_line_limit, so we just
+     * skip over it to simplify the remainder of the code below.
+     */
+    VSTRING_RESET(rdata.str_buf);
+    for (;;) {
+	last_char = smtp_get(session->buffer, session->stream, var_line_limit,
+			     SMTP_GET_FLAG_SKIP);
+	/* XXX Update the per-line time limit. */
+	printable(STR(session->buffer), '?');
+	if (last_char != '\n')
+	    msg_warn("%s: response longer than %d: %.30s...",
+		session->namaddrport, var_line_limit, STR(session->buffer));
+	if (msg_verbose)
+	    msg_info("< %s: %.100s", session->namaddrport, STR(session->buffer));
+
+	/*
+	 * Defend against a denial of service attack by limiting the amount
+	 * of multi-line text that we are willing to store.
+	 */
+	chat_append_flag = (LEN(rdata.str_buf) < var_line_limit);
+	if (chat_append_flag)
+	    smtp_chat_append(session, "In:  ", STR(session->buffer));
+	else {
+	    if (chat_append_skipped == 0)
+		msg_warn("%s: multi-line response longer than %d %.30s...",
+		  session->namaddrport, var_line_limit, STR(rdata.str_buf));
+	    if (chat_append_skipped < INT_MAX)
+		chat_append_skipped++;
+	}
+
+	/*
+	 * Server reply substitution, for fault-injection testing, or for
+	 * working around broken systems. Use with care.
+	 */
+	if (smtp_chat_resp_filter != 0) {
+	    new_reply = dict_get(smtp_chat_resp_filter, STR(session->buffer));
+	    if (new_reply != 0) {
+		msg_info("%s: replacing server reply \"%s\" with \"%s\"",
+		     session->namaddrport, STR(session->buffer), new_reply);
+		vstring_strcpy(session->buffer, new_reply);
+		if (chat_append_flag) {
+		    smtp_chat_append(session, "Replaced-by: ", "");
+		    smtp_chat_append(session, "     ", new_reply);
+		}
+	    } else if (smtp_chat_resp_filter->error != 0) {
+		msg_warn("%s: table %s:%s lookup error for %s",
+			 session->state->request->queue_id,
+			 smtp_chat_resp_filter->type,
+			 smtp_chat_resp_filter->name,
+			 printable(STR(session->buffer), '?'));
+		vstream_longjmp(session->stream, SMTP_ERR_DATA);
+	    }
+	}
+	if (chat_append_flag) {
+	    if (LEN(rdata.str_buf))
+		VSTRING_ADDCH(rdata.str_buf, '\n');
+	    vstring_strcat(rdata.str_buf, STR(session->buffer));
+	}
+
+	/*
+	 * Parse into code and text. Do not ignore garbage (see below).
+	 */
+	for (cp = STR(session->buffer); *cp && ISDIGIT(*cp); cp++)
+	     /* void */ ;
+	if ((three_digs = (cp - STR(session->buffer) == 3)) != 0) {
+	    if (*cp == '-')
+		continue;
+	    if (*cp == ' ' || *cp == 0)
+		break;
+	}
+
+	/*
+	 * XXX Do not simply ignore garbage in the server reply when ESMTP
+	 * command pipelining is turned on.  For example, after sending
+	 * ".<CR><LF>QUIT<CR><LF>" and receiving garbage followed by a
+	 * legitimate 2XX reply, Postfix recognizes the server's QUIT reply
+	 * as the END-OF-DATA reply after garbage, causing mail to be lost.
+	 * 
+	 * Without the ability to store per-domain status information in queue
+	 * files, automatic workarounds are problematic:
+	 * 
+	 * - Automatically deferring delivery creates a "repeated delivery"
+	 * problem when garbage arrives after the DATA stage. Without the
+	 * workaround, Postfix delivers only once.
+	 * 
+	 * - Automatically deferring delivery creates a "no delivery" problem
+	 * when the garbage arrives before the DATA stage. Without the
+	 * workaround, mail might still get through.
+	 * 
+	 * - Automatically turning off pipelining for delayed mail affects
+	 * deliveries to correctly implemented servers, and may also affect
+	 * delivery of large mailing lists.
+	 * 
+	 * So we leave the decision with the administrator, but we don't force
+	 * them to take action, like we would with automatic deferral.  If
+	 * loss of mail is not acceptable then they can turn off pipelining
+	 * for specific sites, or they can turn off pipelining globally when
+	 * they find that there are just too many broken sites.
+	 * 
+	 * Fix 20190621: don't cache an SMTP session after an SMTP protocol
+	 * error. The protocol may be in a bad state. Disable caching here so
+	 * that the protocol engine will send QUIT.
+	 */
+	session->error_mask |= MAIL_ERROR_PROTOCOL;
+	DONT_CACHE_THIS_SESSION;
+	if (session->features & SMTP_FEATURE_PIPELINING) {
+	    msg_warn("%s: non-%s response from %s: %.100s",
+		     session->state->request->queue_id,
+		     smtp_mode ? "ESMTP" : "LMTP",
+		     session->namaddrport, STR(session->buffer));
+	    if (var_helpful_warnings)
+		msg_warn("to prevent loss of mail, turn off command pipelining "
+			 "for %s with the %s parameter",
+			 STR(session->iterator->addr),
+			 VAR_LMTP_SMTP(EHLO_DIS_MAPS));
+	}
+    }
+
+    /*
+     * Extract RFC 821 reply code and RFC 2034 detail. Use a default detail
+     * code if none was given.
+     * 
+     * Ignore out-of-protocol enhanced status codes: codes that accompany 3XX
+     * replies, or codes whose initial digit is out of sync with the reply
+     * code.
+     * 
+     * XXX Potential stability problem. In order to save memory, the queue
+     * manager stores DSNs in a compact manner:
+     * 
+     * - empty strings are represented by null pointers,
+     * 
+     * - the status and reason are required to be non-empty.
+     * 
+     * Other Postfix daemons inherit this behavior, because they use the same
+     * DSN support code. This means that everything that receives DSNs must
+     * cope with null pointers for the optional DSN attributes, and that
+     * everything that provides DSN information must provide a non-empty
+     * status and reason, otherwise the DSN support code wil panic().
+     * 
+     * Thus, when the remote server sends a malformed reply (or 3XX out of
+     * context) we should not panic() in DSN_COPY() just because we don't
+     * have a status. Robustness suggests that we supply a status here, and
+     * that we leave it up to the down-stream code to override the
+     * server-supplied status in case of an error we can't detect here, such
+     * as an out-of-order server reply.
+     */
+    VSTRING_TERMINATE(rdata.str_buf);
+    vstring_strcpy(rdata.dsn_buf, "5.5.0");	/* SAFETY! protocol error */
+    if (three_digs != 0) {
+	rdata.code = atoi(STR(session->buffer));
+	if (strchr("245", STR(session->buffer)[0]) != 0) {
+	    for (cp = STR(session->buffer) + 4; *cp == ' '; cp++)
+		 /* void */ ;
+	    if ((len = dsn_valid(cp)) > 0 && *cp == *STR(session->buffer)) {
+		vstring_strncpy(rdata.dsn_buf, cp, len);
+	    } else {
+		vstring_strcpy(rdata.dsn_buf, "0.0.0");
+		STR(rdata.dsn_buf)[0] = STR(session->buffer)[0];
+	    }
+	}
+    } else {
+	rdata.code = 0;
+    }
+    rdata.dsn = STR(rdata.dsn_buf);
+    rdata.str = STR(rdata.str_buf);
+    return (&rdata);
+}
+
+/* print_line - line_wrap callback */
+
+static void print_line(const char *str, int len, int indent, void *context)
+{
+    VSTREAM *notice = (VSTREAM *) context;
+
+    post_mail_fprintf(notice, " %*s%.*s", indent, "", len, str);
+}
+
+/* smtp_chat_notify - notify postmaster */
+
+void    smtp_chat_notify(SMTP_SESSION *session)
+{
+    const char *myname = "smtp_chat_notify";
+    VSTREAM *notice;
+    char  **cpp;
+
+    /*
+     * Sanity checks.
+     */
+    if (session->history == 0)
+	msg_panic("%s: no conversation history", myname);
+    if (msg_verbose)
+	msg_info("%s: notify postmaster", myname);
+
+    /*
+     * Construct a message for the postmaster, explaining what this is all
+     * about. This is junk mail: don't send it when the mail posting service
+     * is unavailable, and use the double bounce sender address, to prevent
+     * mail bounce wars. Always prepend one space to message content that we
+     * generate from untrusted data.
+     */
+#define NULL_TRACE_FLAGS	0
+#define NO_QUEUE_ID		((VSTRING *) 0)
+#define LENGTH	78
+#define INDENT	4
+
+    notice = post_mail_fopen_nowait(mail_addr_double_bounce(),
+				    var_error_rcpt,
+				    MAIL_SRC_MASK_NOTIFY, NULL_TRACE_FLAGS,
+				    SMTPUTF8_FLAG_NONE, NO_QUEUE_ID);
+    if (notice == 0) {
+	msg_warn("postmaster notify: %m");
+	return;
+    }
+    post_mail_fprintf(notice, "From: %s (Mail Delivery System)",
+		      mail_addr_mail_daemon());
+    post_mail_fprintf(notice, "To: %s (Postmaster)", var_error_rcpt);
+    post_mail_fprintf(notice, "Subject: %s %s client: errors from %s",
+		      var_mail_name, smtp_mode ? "SMTP" : "LMTP",
+		      session->namaddrport);
+    post_mail_fputs(notice, "");
+    post_mail_fprintf(notice, "Unexpected response from %s.",
+		      session->namaddrport);
+    post_mail_fputs(notice, "");
+    post_mail_fputs(notice, "Transcript of session follows.");
+    post_mail_fputs(notice, "");
+    argv_terminate(session->history);
+    for (cpp = session->history->argv; *cpp; cpp++)
+	line_wrap(printable(*cpp, '?'), LENGTH, INDENT, print_line,
+		  (void *) notice);
+    post_mail_fputs(notice, "");
+    post_mail_fprintf(notice, "For other details, see the local mail logfile");
+    (void) post_mail_fclose(notice);
+}
diff --git a/src/smtp/smtp_connect.c b/src/smtp/smtp_connect.c
new file mode 100644
index 0000000..4d48883
--- /dev/null
+++ b/src/smtp/smtp_connect.c
@@ -0,0 +1,1205 @@
+/*++
+/* NAME
+/*	smtp_connect 3
+/* SUMMARY
+/*	connect to SMTP/LMTP server and deliver
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	int	smtp_connect(state)
+/*	SMTP_STATE *state;
+/* DESCRIPTION
+/*	This module implements SMTP/LMTP connection management and controls
+/*	mail delivery.
+/*
+/*	smtp_connect() attempts to establish an SMTP/LMTP session with a host
+/*	that represents the destination domain, or with an optional fallback
+/*	relay when {the destination cannot be found, or when all the
+/*	destination servers are unavailable}. It skips over IP addresses
+/*	that fail to complete the SMTP/LMTP handshake and tries to find
+/*	an alternate server when an SMTP/LMTP session fails to deliver.
+/*
+/*	This layer also controls what connections are retrieved from
+/*	the connection cache, and what connections are saved to the cache.
+/*
+/*	The destination is either a host (or domain) name or a numeric
+/*	address. Symbolic or numeric service port information may be
+/*	appended, separated by a colon (":"). In the case of LMTP,
+/*	destinations may be specified as "unix:pathname", "inet:host"
+/*	or "inet:host:port".
+/*
+/*	With SMTP, the Internet domain name service is queried for mail
+/*	exchanger hosts. Quote the domain name with `[' and `]' to
+/*	suppress mail exchanger lookups.
+/*
+/*	Numerical address information should always be quoted with `[]'.
+/* DIAGNOSTICS
+/*	The delivery status is the result value.
+/* SEE ALSO
+/*	smtp_proto(3) SMTP client protocol
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	Connection caching in cooperation with:
+/*	Victor Duchovni
+/*	Morgan Stanley
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+#ifndef IPPORT_SMTP
+#define IPPORT_SMTP 25
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstream.h>
+#include <vstring.h>
+#include <split_at.h>
+#include <mymalloc.h>
+#include <inet_addr_list.h>
+#include <iostuff.h>
+#include <timed_connect.h>
+#include <stringops.h>
+#include <host_port.h>
+#include <sane_connect.h>
+#include <myaddrinfo.h>
+#include <sock_addr.h>
+#include <inet_proto.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <own_inet_addr.h>
+#include <deliver_pass.h>
+#include <mail_error.h>
+#include <dsn_buf.h>
+#include <mail_addr.h>
+
+/* DNS library. */
+
+#include <dns.h>
+
+/* Application-specific. */
+
+#include <smtp.h>
+#include <smtp_addr.h>
+#include <smtp_reuse.h>
+
+ /*
+  * Forward declaration.
+  */
+static SMTP_SESSION *smtp_connect_sock(int, struct sockaddr *, int,
+				               SMTP_ITERATOR *, DSN_BUF *,
+				               int);
+
+/* smtp_connect_unix - connect to UNIX-domain address */
+
+static SMTP_SESSION *smtp_connect_unix(SMTP_ITERATOR *iter, DSN_BUF *why,
+				               int sess_flags)
+{
+    const char *myname = "smtp_connect_unix";
+    struct sockaddr_un sock_un;
+    const char *addr = STR(iter->addr);
+    int     len = strlen(addr);
+    int     sock;
+
+    dsb_reset(why);				/* Paranoia */
+
+    /*
+     * Sanity checks.
+     */
+    if (len >= (int) sizeof(sock_un.sun_path)) {
+	msg_warn("unix-domain name too long: %s", addr);
+	dsb_simple(why, "4.3.5", "Server configuration error");
+	return (0);
+    }
+
+    /*
+     * Initialize.
+     */
+    memset((void *) &sock_un, 0, sizeof(sock_un));
+    sock_un.sun_family = AF_UNIX;
+#ifdef HAS_SUN_LEN
+    sock_un.sun_len = len + 1;
+#endif
+    memcpy(sock_un.sun_path, addr, len + 1);
+
+    /*
+     * Create a client socket.
+     */
+    if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+	msg_fatal("%s: socket: %m", myname);
+
+    /*
+     * Connect to the server.
+     */
+    if (msg_verbose)
+	msg_info("%s: trying: %s...", myname, addr);
+
+    return (smtp_connect_sock(sock, (struct sockaddr *) &sock_un,
+			      sizeof(sock_un), iter, why, sess_flags));
+}
+
+/* smtp_connect_addr - connect to explicit address */
+
+static SMTP_SESSION *smtp_connect_addr(SMTP_ITERATOR *iter, DSN_BUF *why,
+				               int sess_flags)
+{
+    const char *myname = "smtp_connect_addr";
+    struct sockaddr_storage ss;		/* remote */
+    struct sockaddr *sa = (struct sockaddr *) &ss;
+    SOCKADDR_SIZE salen = sizeof(ss);
+    MAI_HOSTADDR_STR hostaddr;
+    DNS_RR *addr = iter->rr;
+    unsigned port = iter->port;
+    int     sock;
+    char   *bind_addr;
+    char   *bind_var;
+
+    dsb_reset(why);				/* Paranoia */
+
+    /*
+     * Sanity checks.
+     */
+    if (dns_rr_to_sa(addr, port, sa, &salen) != 0) {
+	msg_warn("%s: skip address type %s: %m",
+		 myname, dns_strtype(addr->type));
+	dsb_simple(why, "4.4.0", "network address conversion failed: %m");
+	return (0);
+    }
+
+    /*
+     * Initialize.
+     */
+    if ((sock = socket(sa->sa_family, SOCK_STREAM, 0)) < 0)
+	msg_fatal("%s: socket: %m", myname);
+
+    if (inet_windowsize > 0)
+	set_inet_windowsize(sock, inet_windowsize);
+
+    /*
+     * Allow the sysadmin to specify the source address, for example, as "-o
+     * smtp_bind_address=x.x.x.x" in the master.cf file.
+     */
+#ifdef HAS_IPV6
+    if (sa->sa_family == AF_INET6) {
+	bind_addr = var_smtp_bind_addr6;
+	bind_var = VAR_LMTP_SMTP(BIND_ADDR6);
+    } else
+#endif
+    if (sa->sa_family == AF_INET) {
+	bind_addr = var_smtp_bind_addr;
+	bind_var = VAR_LMTP_SMTP(BIND_ADDR);
+    } else
+	bind_var = bind_addr = "";
+    if (*bind_addr) {
+	int     aierr;
+	struct addrinfo *res0;
+
+	if ((aierr = hostaddr_to_sockaddr(bind_addr, (char *) 0, 0, &res0)) != 0)
+	    msg_fatal("%s: bad %s parameter: %s: %s",
+		      myname, bind_var, bind_addr, MAI_STRERROR(aierr));
+	if (bind(sock, res0->ai_addr, res0->ai_addrlen) < 0)
+	    msg_warn("%s: bind %s: %m", myname, bind_addr);
+	else if (msg_verbose)
+	    msg_info("%s: bind %s", myname, bind_addr);
+	freeaddrinfo(res0);
+    }
+
+    /*
+     * When running as a virtual host, bind to the virtual interface so that
+     * the mail appears to come from the "right" machine address.
+     * 
+     * XXX The IPv6 patch expands the null host (as client endpoint) and uses
+     * the result as the loopback address list.
+     */
+    else {
+	int     count = 0;
+	struct sockaddr *own_addr = 0;
+	INET_ADDR_LIST *addr_list = own_inet_addr_list();
+	struct sockaddr_storage *s;
+
+	for (s = addr_list->addrs; s < addr_list->addrs + addr_list->used; s++) {
+	    if (SOCK_ADDR_FAMILY(s) == sa->sa_family) {
+		if (count++ > 0)
+		    break;
+		own_addr = SOCK_ADDR_PTR(s);
+	    }
+	}
+	if (count == 1 && !sock_addr_in_loopback(own_addr)) {
+	    if (bind(sock, own_addr, SOCK_ADDR_LEN(own_addr)) < 0) {
+		SOCKADDR_TO_HOSTADDR(own_addr, SOCK_ADDR_LEN(own_addr),
+				     &hostaddr, (MAI_SERVPORT_STR *) 0, 0);
+		msg_warn("%s: bind %s: %m", myname, hostaddr.buf);
+	    } else if (msg_verbose) {
+		SOCKADDR_TO_HOSTADDR(own_addr, SOCK_ADDR_LEN(own_addr),
+				     &hostaddr, (MAI_SERVPORT_STR *) 0, 0);
+		msg_info("%s: bind %s", myname, hostaddr.buf);
+	    }
+	}
+    }
+
+    /*
+     * Connect to the server.
+     */
+    if (msg_verbose)
+	msg_info("%s: trying: %s[%s] port %d...",
+		 myname, STR(iter->host), STR(iter->addr), ntohs(port));
+
+    return (smtp_connect_sock(sock, sa, salen, iter, why, sess_flags));
+}
+
+/* smtp_connect_sock - connect a socket over some transport */
+
+static SMTP_SESSION *smtp_connect_sock(int sock, struct sockaddr *sa,
+				               int salen,
+				               SMTP_ITERATOR *iter,
+				               DSN_BUF *why,
+				               int sess_flags)
+{
+    int     conn_stat;
+    int     saved_errno;
+    VSTREAM *stream;
+    time_t  start_time;
+    const char *name = STR(iter->host);
+    const char *addr = STR(iter->addr);
+    unsigned port = iter->port;
+
+    start_time = time((time_t *) 0);
+    if (var_smtp_conn_tmout > 0) {
+	non_blocking(sock, NON_BLOCKING);
+	conn_stat = timed_connect(sock, sa, salen, var_smtp_conn_tmout);
+	saved_errno = errno;
+	non_blocking(sock, BLOCKING);
+	errno = saved_errno;
+    } else {
+	conn_stat = sane_connect(sock, sa, salen);
+    }
+    if (conn_stat < 0) {
+	if (port)
+	    dsb_simple(why, "4.4.1", "connect to %s[%s]:%d: %m",
+		       name, addr, ntohs(port));
+	else
+	    dsb_simple(why, "4.4.1", "connect to %s[%s]: %m", name, addr);
+	close(sock);
+	return (0);
+    }
+    stream = vstream_fdopen(sock, O_RDWR);
+
+    /*
+     * Avoid poor performance when TCP MSS > VSTREAM_BUFSIZE.
+     */
+    if (sa->sa_family == AF_INET
+#ifdef AF_INET6
+	|| sa->sa_family == AF_INET6
+#endif
+	)
+	vstream_tweak_tcp(stream);
+
+    /*
+     * Bundle up what we have into a nice SMTP_SESSION object.
+     */
+    return (smtp_session_alloc(stream, iter, start_time, sess_flags));
+}
+
+/* smtp_parse_destination - parse host/port destination */
+
+static char *smtp_parse_destination(char *destination, char *def_service,
+				            char **hostp, unsigned *portp)
+{
+    char   *buf = mystrdup(destination);
+    char   *service;
+    struct servent *sp;
+    char   *protocol = "tcp";		/* XXX configurable? */
+    unsigned port;
+    const char *err;
+
+    if (msg_verbose)
+	msg_info("smtp_parse_destination: %s %s", destination, def_service);
+
+    /*
+     * Parse the host/port information. We're working with a copy of the
+     * destination argument so the parsing can be destructive.
+     */
+    if ((err = host_port(buf, hostp, (char *) 0, &service, def_service)) != 0)
+	msg_fatal("%s in server description: %s", err, destination);
+
+    /*
+     * Convert service to port number, network byte order.
+     */
+    if (alldig(service)) {
+	if ((port = atoi(service)) >= 65536 || port == 0)
+	    msg_fatal("bad network port in destination: %s", destination);
+	*portp = htons(port);
+    } else {
+	if ((sp = getservbyname(service, protocol)) == 0)
+	    msg_fatal("unknown service: %s/%s", service, protocol);
+	*portp = sp->s_port;
+    }
+    return (buf);
+}
+
+/* smtp_cleanup_session - clean up after using a session */
+
+static void smtp_cleanup_session(SMTP_STATE *state)
+{
+    DELIVER_REQUEST *request = state->request;
+    SMTP_SESSION *session = state->session;
+    int     throttled;
+
+    /*
+     * Inform the postmaster of trouble.
+     * 
+     * XXX Don't send notifications about errors while sending notifications.
+     */
+#define POSSIBLE_NOTIFICATION(sender) \
+	(*sender == 0 || strcmp(sender, mail_addr_double_bounce()) == 0)
+
+    if (session->history != 0
+	&& (session->error_mask & name_mask(VAR_NOTIFY_CLASSES,
+					    mail_error_masks,
+					    var_notify_classes)) != 0
+	&& POSSIBLE_NOTIFICATION(request->sender) == 0)
+	smtp_chat_notify(session);
+
+    /*
+     * When session caching is enabled, cache the first good session for this
+     * delivery request under the next-hop destination, and cache all good
+     * sessions under their server network address (destroying the session in
+     * the process).
+     * 
+     * Caching under the next-hop destination name (rather than the fall-back
+     * destination) allows us to skip over non-responding primary or backup
+     * hosts. In fact, this is the only benefit of caching logical to
+     * physical bindings; caching a session under its own hostname provides
+     * no performance benefit, given the way smtp_connect() works.
+     */
+    throttled = THIS_SESSION_IS_THROTTLED;	/* smtp_quit() may fail */
+    if (THIS_SESSION_IS_EXPIRED)
+	smtp_quit(state);			/* also disables caching */
+    if (THIS_SESSION_IS_CACHED
+    /* Redundant tests for safety... */
+	&& vstream_ferror(session->stream) == 0
+	&& vstream_feof(session->stream) == 0) {
+	smtp_save_session(state, SMTP_KEY_MASK_SCACHE_DEST_LABEL,
+			  SMTP_KEY_MASK_SCACHE_ENDP_LABEL);
+    } else {
+	smtp_session_free(session);
+    }
+    state->session = 0;
+
+    /*
+     * If this session was good, reset the scache next-hop destination, so
+     * that we won't cache connections to less-preferred servers under the
+     * same next-hop destination. Otherwise we could end up skipping over the
+     * available and more-preferred servers.
+     */
+    if (HAVE_SCACHE_REQUEST_NEXTHOP(state) && !throttled)
+	CLEAR_SCACHE_REQUEST_NEXTHOP(state);
+
+    /*
+     * Clean up the lists with todo and dropped recipients.
+     */
+    smtp_rcpt_cleanup(state);
+
+    /*
+     * Reset profiling info.
+     * 
+     * XXX When one delivery request results in multiple sessions, the set-up
+     * and transmission latencies of the earlier sessions will count as
+     * connection set-up time for the later sessions.
+     * 
+     * XXX On the other hand, when we first try to connect to one or more dead
+     * hosts before we reach a good host, then all that time must be counted
+     * as connection set-up time for the session with the good host.
+     * 
+     * XXX So this set-up attribution problem exists only when we actually
+     * engage in a session, spend a lot of time delivering a message, find
+     * that it fails, and then connect to an alternate host.
+     */
+    memset((void *) &request->msg_stats.conn_setup_done, 0,
+	   sizeof(request->msg_stats.conn_setup_done));
+    memset((void *) &request->msg_stats.deliver_done, 0,
+	   sizeof(request->msg_stats.deliver_done));
+    request->msg_stats.reuse_count = 0;
+}
+
+static void smtp_cache_policy(SMTP_STATE *state, const char *dest)
+{
+    DELIVER_REQUEST *request = state->request;
+
+    state->misc_flags &= ~SMTP_MISC_FLAG_CONN_CACHE_MASK;
+
+    if (smtp_cache_dest && string_list_match(smtp_cache_dest, dest)) {
+	state->misc_flags |= SMTP_MISC_FLAG_CONN_CACHE_MASK;
+    } else if (var_smtp_cache_demand) {
+	if (request->flags & DEL_REQ_FLAG_CONN_LOAD)
+	    state->misc_flags |= SMTP_MISC_FLAG_CONN_LOAD;
+	if (request->flags & DEL_REQ_FLAG_CONN_STORE)
+	    state->misc_flags |= SMTP_MISC_FLAG_CONN_STORE;
+    }
+}
+
+/* smtp_connect_local - connect to local server */
+
+static void smtp_connect_local(SMTP_STATE *state, const char *path)
+{
+    const char *myname = "smtp_connect_local";
+    SMTP_ITERATOR *iter = state->iterator;
+    SMTP_SESSION *session;
+    DSN_BUF *why = state->why;
+
+    /*
+     * Do not silently ignore an unused setting.
+     */
+    if (*var_fallback_relay)
+	msg_warn("ignoring \"%s = %s\" setting for non-TCP connections",
+		 VAR_LMTP_FALLBACK, var_fallback_relay);
+
+    /*
+     * It's too painful to weave this code into the SMTP connection
+     * management routine.
+     * 
+     * Connection cache management is based on the UNIX-domain pathname, without
+     * the "unix:" prefix.
+     */
+    smtp_cache_policy(state, path);
+    if (state->misc_flags & SMTP_MISC_FLAG_CONN_CACHE_MASK)
+	SET_SCACHE_REQUEST_NEXTHOP(state, path);
+
+    /*
+     * Here we ensure that the iter->addr member refers to a copy of the
+     * UNIX-domain pathname, so that smtp_save_session() will cache the
+     * connection using the pathname as the physical endpoint name.
+     * 
+     * We set dest=path for backwards compatibility.
+     */
+#define NO_PORT	0
+
+    SMTP_ITER_INIT(iter, path, var_myhostname, path, NO_PORT, state);
+
+    /*
+     * Opportunistic TLS for unix domain sockets does not make much sense,
+     * since the channel is private, mere encryption without authentication
+     * is just wasted cycles and opportunity for breakage. Since we are not
+     * willing to retry after TLS handshake failures here, we downgrade "may"
+     * no "none". Nothing is lost, and much waste is avoided.
+     * 
+     * We don't know who is authenticating whom, so if a client cert is
+     * available, "encrypt" may be a sensible policy. Otherwise, we also
+     * downgrade "encrypt" to "none", this time just to avoid waste.
+     * 
+     * We use smtp_reuse_nexthop() instead of smtp_reuse_addr(), so that we can
+     * reuse a SASL-authenticated connection (however unlikely this scenario
+     * may be). The smtp_reuse_addr() interface currently supports only reuse
+     * of SASL-unauthenticated connections.
+     */
+#ifdef USE_TLS
+    if (!smtp_tls_policy_cache_query(why, state->tls, iter)) {
+	msg_warn("TLS policy lookup error for %s/%s: %s",
+		 STR(iter->host), STR(iter->addr), STR(why->reason));
+	return;
+    }
+#endif
+    if ((state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD) == 0
+	|| (session = smtp_reuse_nexthop(state,
+				     SMTP_KEY_MASK_SCACHE_DEST_LABEL)) == 0)
+	session = smtp_connect_unix(iter, why, state->misc_flags);
+    if ((state->session = session) != 0) {
+	session->state = state;
+#ifdef USE_TLS
+	session->tls_nexthop = var_myhostname;	/* for TLS_LEV_SECURE */
+	if (state->tls->level == TLS_LEV_MAY) {
+	    msg_warn("%s: opportunistic TLS encryption is not appropriate "
+		     "for unix-domain destinations.", myname);
+	    state->tls->level = TLS_LEV_NONE;
+	}
+#endif
+	/* All delivery errors bounce or defer. */
+	state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER;
+
+	/*
+	 * When a TLS handshake fails, the stream is marked "dead" to avoid
+	 * further I/O over a broken channel.
+	 */
+	if ((session->features & SMTP_FEATURE_FROM_CACHE) == 0
+	    && smtp_helo(state) != 0) {
+	    if (!THIS_SESSION_IS_FORBIDDEN
+		&& vstream_ferror(session->stream) == 0
+		&& vstream_feof(session->stream) == 0)
+		smtp_quit(state);
+	} else {
+	    smtp_xfer(state);
+	}
+
+	/*
+	 * With opportunistic TLS disabled we don't expect to be asked to
+	 * retry connections without TLS, and so we expect the final server
+	 * flag to stay on.
+	 */
+	if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_SERVER) == 0)
+	    msg_panic("%s: unix-domain destination not final!", myname);
+	smtp_cleanup_session(state);
+    }
+
+    /*
+     * Cleanup.
+     */
+    if (HAVE_SCACHE_REQUEST_NEXTHOP(state))
+	CLEAR_SCACHE_REQUEST_NEXTHOP(state);
+}
+
+/* smtp_scrub_address_list - delete all cached addresses from list */
+
+static void smtp_scrub_addr_list(HTABLE *cached_addr, DNS_RR **addr_list)
+{
+    MAI_HOSTADDR_STR hostaddr;
+    DNS_RR *addr;
+    DNS_RR *next;
+
+    /*
+     * XXX Extend the DNS_RR structure with fields for the printable address
+     * and/or binary sockaddr representations, so that we can avoid repeated
+     * binary->string transformations for the same address.
+     */
+    for (addr = *addr_list; addr; addr = next) {
+	next = addr->next;
+	if (dns_rr_to_pa(addr, &hostaddr) == 0) {
+	    msg_warn("cannot convert type %s record to printable address",
+		     dns_strtype(addr->type));
+	    continue;
+	}
+	if (htable_locate(cached_addr, hostaddr.buf))
+	    *addr_list = dns_rr_remove(*addr_list, addr);
+    }
+}
+
+/* smtp_update_addr_list - common address list update */
+
+static void smtp_update_addr_list(DNS_RR **addr_list, const char *server_addr,
+				          int session_count)
+{
+    DNS_RR *addr;
+    DNS_RR *next;
+    int     aierr;
+    struct addrinfo *res0;
+
+    if (*addr_list == 0)
+	return;
+
+    /*
+     * Truncate the address list if we are not going to use it anyway.
+     */
+    if (session_count == var_smtp_mxsess_limit
+	|| session_count == var_smtp_mxaddr_limit) {
+	dns_rr_free(*addr_list);
+	*addr_list = 0;
+	return;
+    }
+
+    /*
+     * Convert server address to internal form, and look it up in the address
+     * list.
+     * 
+     * XXX smtp_reuse_session() breaks if we remove two or more adjacent list
+     * elements but do not truncate the list to zero length.
+     * 
+     * XXX Extend the SMTP_SESSION structure with sockaddr information so that
+     * we can avoid repeated string->binary transformations for the same
+     * address.
+     */
+    if ((aierr = hostaddr_to_sockaddr(server_addr, (char *) 0, 0, &res0)) != 0) {
+	msg_warn("hostaddr_to_sockaddr %s: %s",
+		 server_addr, MAI_STRERROR(aierr));
+    } else {
+	for (addr = *addr_list; addr; addr = next) {
+	    next = addr->next;
+	    if (DNS_RR_EQ_SA(addr, (struct sockaddr *) res0->ai_addr)) {
+		*addr_list = dns_rr_remove(*addr_list, addr);
+		break;
+	    }
+	}
+	freeaddrinfo(res0);
+    }
+}
+
+/* smtp_reuse_session - try to use existing connection, return session count */
+
+static int smtp_reuse_session(SMTP_STATE *state, DNS_RR **addr_list,
+			              int domain_best_pref)
+{
+    int     session_count = 0;
+    DNS_RR *addr;
+    DNS_RR *next;
+    MAI_HOSTADDR_STR hostaddr;
+    SMTP_SESSION *session;
+    SMTP_ITERATOR *iter = state->iterator;
+    DSN_BUF *why = state->why;
+
+    /*
+     * First, search the cache by delivery request nexthop. We truncate the
+     * server address list when all the sessions for this destination are
+     * used up, to reduce the number of variables that need to be checked
+     * later.
+     * 
+     * Note: connection reuse by delivery request nexthop restores the "best MX"
+     * bit.
+     * 
+     * smtp_reuse_nexthop() clobbers the iterators's "dest" attribute. We save
+     * and restore it here, so that subsequent connections will use the
+     * proper nexthop information.
+     * 
+     * We don't use TLS level info for nexthop-based connection cache storage
+     * keys. The combination of (service, nexthop, etc.) should be stable
+     * over the time range of interest, and the policy is still enforced on
+     * an individual connection to an MX host, before that connection is
+     * stored under a nexthop- or host-based storage key.
+     */
+#ifdef USE_TLS
+    smtp_tls_policy_dummy(state->tls);
+#endif
+    SMTP_ITER_SAVE_DEST(state->iterator);
+    if (*addr_list && SMTP_RCPT_LEFT(state) > 0
+	&& HAVE_SCACHE_REQUEST_NEXTHOP(state)
+	&& (session = smtp_reuse_nexthop(state, SMTP_KEY_MASK_SCACHE_DEST_LABEL)) != 0) {
+	session_count = 1;
+	smtp_update_addr_list(addr_list, STR(iter->addr), session_count);
+	if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP)
+	    && *addr_list == 0)
+	    state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER;
+	smtp_xfer(state);
+	smtp_cleanup_session(state);
+    }
+    SMTP_ITER_RESTORE_DEST(state->iterator);
+
+    /*
+     * Second, search the cache by primary MX address. Again, we use address
+     * list truncation so that we have to check fewer variables later.
+     * 
+     * XXX This loop is safe because smtp_update_addr_list() either truncates
+     * the list to zero length, or removes at most one list element.
+     * 
+     * Currently, we use smtp_reuse_addr() only for SASL-unauthenticated
+     * connections. Furthermore, we rely on smtp_reuse_addr() to look up an
+     * existing SASL-unauthenticated connection only when a new connection
+     * would be guaranteed not to require SASL authentication.
+     * 
+     * In addition, we rely on smtp_reuse_addr() to look up an existing
+     * plaintext connection only when a new connection would be guaranteed
+     * not to use TLS.
+     * 
+     * For more precise control over reuse, the iterator should look up SASL and
+     * TLS policy as it evaluates mail exchangers in order, instead of
+     * relying on duplicate lookup request code in smtp_reuse(3) and
+     * smtp_session(3).
+     */
+    for (addr = *addr_list; SMTP_RCPT_LEFT(state) > 0 && addr; addr = next) {
+	if (addr->pref != domain_best_pref)
+	    break;
+	next = addr->next;
+	if (dns_rr_to_pa(addr, &hostaddr) == 0) {
+	    msg_warn("cannot convert type %s record to printable address",
+		     dns_strtype(addr->type));
+	    /* XXX Assume there is no code at the end of this loop. */
+	    continue;
+	}
+	vstring_strcpy(iter->addr, hostaddr.buf);
+	vstring_strcpy(iter->host, SMTP_HNAME(addr));
+	iter->rr = addr;
+#ifdef USE_TLS
+	if (!smtp_tls_policy_cache_query(why, state->tls, iter)) {
+	    msg_warn("TLS policy lookup error for %s/%s: %s",
+		     STR(iter->dest), STR(iter->host), STR(why->reason));
+	    continue;
+	    /* XXX Assume there is no code at the end of this loop. */
+	}
+#endif
+	if ((session = smtp_reuse_addr(state,
+				   SMTP_KEY_MASK_SCACHE_ENDP_LABEL)) != 0) {
+	    session->features |= SMTP_FEATURE_BEST_MX;
+	    session_count += 1;
+	    smtp_update_addr_list(addr_list, STR(iter->addr), session_count);
+	    if (*addr_list == 0)
+		next = 0;
+	    if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP)
+		&& next == 0)
+		state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER;
+	    smtp_xfer(state);
+	    smtp_cleanup_session(state);
+	}
+    }
+    return (session_count);
+}
+
+/* smtp_connect_inet - establish network connection */
+
+static void smtp_connect_inet(SMTP_STATE *state, const char *nexthop,
+			              char *def_service)
+{
+    DELIVER_REQUEST *request = state->request;
+    SMTP_ITERATOR *iter = state->iterator;
+    ARGV   *sites;
+    char   *dest;
+    char  **cpp;
+    int     non_fallback_sites;
+    int     retry_plain = 0;
+    DSN_BUF *why = state->why;
+
+    /*
+     * For sanity, require that at least one of INET or INET6 is enabled.
+     * Otherwise, we can't look up interface information, and we can't
+     * convert names or addresses.
+     */
+    if (inet_proto_info()->ai_family_list[0] == 0) {
+	dsb_simple(why, "4.4.4", "all network protocols are disabled");
+	return;
+    }
+
+    /*
+     * Do a null destination sanity check in case the primary destination is
+     * a list that consists of only separators.
+     */
+    sites = argv_split(nexthop, CHARS_COMMA_SP);
+    if (sites->argc == 0)
+	msg_panic("null destination: \"%s\"", nexthop);
+    non_fallback_sites = sites->argc;
+    argv_split_append(sites, var_fallback_relay, CHARS_COMMA_SP);
+
+    /*
+     * Don't give up after a hard host lookup error until we have tried the
+     * fallback relay servers.
+     * 
+     * Don't bounce mail after a host lookup problem with a relayhost or with a
+     * fallback relay.
+     * 
+     * Don't give up after a qualifying soft error until we have tried all
+     * qualifying backup mail servers.
+     * 
+     * All this means that error handling and error reporting depends on whether
+     * the error qualifies for trying to deliver to a backup mail server, or
+     * whether we're looking up a relayhost or fallback relay. The challenge
+     * then is to build this into the pre-existing SMTP client without
+     * getting lost in the complexity.
+     */
+#define IS_FALLBACK_RELAY(cpp, sites, non_fallback_sites) \
+	    (*(cpp) && (cpp) >= (sites)->argv + (non_fallback_sites))
+
+    for (cpp = sites->argv, (state->misc_flags |= SMTP_MISC_FLAG_FIRST_NEXTHOP);
+	 SMTP_RCPT_LEFT(state) > 0 && (dest = *cpp) != 0;
+	 cpp++, (state->misc_flags &= ~SMTP_MISC_FLAG_FIRST_NEXTHOP)) {
+	char   *dest_buf;
+	char   *domain;
+	unsigned port;
+	DNS_RR *addr_list;
+	DNS_RR *addr;
+	DNS_RR *next;
+	int     addr_count;
+	int     sess_count;
+	SMTP_SESSION *session;
+	int     lookup_mx;
+	unsigned domain_best_pref;
+	MAI_HOSTADDR_STR hostaddr;
+
+	if (cpp[1] == 0)
+	    state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP;
+
+	/*
+	 * Parse the destination. If no TCP port is specified, use the port
+	 * that is reserved for the protocol (SMTP or LMTP).
+	 */
+	dest_buf = smtp_parse_destination(dest, def_service, &domain, &port);
+	if (var_helpful_warnings && var_smtp_tls_wrappermode == 0
+	    && ntohs(port) == 465) {
+	    msg_info("SMTPS wrappermode (TCP port 465) requires setting "
+		     "\"%s = yes\", and \"%s = encrypt\" (or stronger)",
+		     VAR_LMTP_SMTP(TLS_WRAPPER), VAR_LMTP_SMTP(TLS_LEVEL));
+	}
+#define NO_HOST	""				/* safety */
+#define NO_ADDR	""				/* safety */
+
+	SMTP_ITER_INIT(iter, dest, NO_HOST, NO_ADDR, port, state);
+
+	/*
+	 * Resolve an SMTP or LMTP server. In the case of SMTP, skip mail
+	 * exchanger lookups when a quoted host is specified or when DNS
+	 * lookups are disabled.
+	 */
+	if (msg_verbose)
+	    msg_info("connecting to %s port %d", domain, ntohs(port));
+	if (smtp_mode) {
+	    if (ntohs(port) == IPPORT_SMTP)
+		state->misc_flags |= SMTP_MISC_FLAG_LOOP_DETECT;
+	    else
+		state->misc_flags &= ~SMTP_MISC_FLAG_LOOP_DETECT;
+	    lookup_mx = (smtp_dns_support != SMTP_DNS_DISABLED && *dest != '[');
+	} else
+	    lookup_mx = 0;
+	if (!lookup_mx) {
+	    addr_list = smtp_host_addr(domain, state->misc_flags, why);
+	    /* XXX We could be an MX host for this destination... */
+	} else {
+	    int     i_am_mx = 0;
+
+	    addr_list = smtp_domain_addr(domain, &iter->mx, state->misc_flags,
+					 why, &i_am_mx);
+	    /* If we're MX host, don't connect to non-MX backups. */
+	    if (i_am_mx)
+		state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP;
+	}
+
+	/*
+	 * Don't try fall-back hosts if mail loops to myself. That would just
+	 * make the problem worse.
+	 */
+	if (addr_list == 0 && SMTP_HAS_LOOP_DSN(why))
+	    state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP;
+
+	/*
+	 * No early loop exit or we have a memory leak with dest_buf.
+	 */
+	if (addr_list)
+	    domain_best_pref = addr_list->pref;
+
+	/*
+	 * When connection caching is enabled, store the first good
+	 * connection for this delivery request under the delivery request
+	 * next-hop name. Good connections will also be stored under their
+	 * specific server IP address.
+	 * 
+	 * XXX smtp_session_cache_destinations specifies domain names without
+	 * :port, because : is already used for maptype:mapname. Because of
+	 * this limitation we use the bare domain without the optional [] or
+	 * non-default TCP port.
+	 * 
+	 * Opportunistic (a.k.a. on-demand) session caching on request by the
+	 * queue manager. This is turned temporarily when a destination has a
+	 * high volume of mail in the active queue. When the surge reaches
+	 * its end, the queue manager requests that connections be retrieved
+	 * but not stored.
+	 */
+	if (addr_list && (state->misc_flags & SMTP_MISC_FLAG_FIRST_NEXTHOP)) {
+	    smtp_cache_policy(state, domain);
+	    if (state->misc_flags & SMTP_MISC_FLAG_CONN_CACHE_MASK)
+		SET_SCACHE_REQUEST_NEXTHOP(state, dest);
+	}
+
+	/*
+	 * Delete visited cached hosts from the address list.
+	 * 
+	 * Optionally search the connection cache by domain name or by primary
+	 * MX address before we try to create new connections.
+	 * 
+	 * Enforce the MX session and MX address counts per next-hop or
+	 * fall-back destination. smtp_reuse_session() will truncate the
+	 * address list when either limit is reached.
+	 */
+	if (addr_list && (state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD)) {
+	    if (state->cache_used->used > 0)
+		smtp_scrub_addr_list(state->cache_used, &addr_list);
+	    sess_count = addr_count =
+		smtp_reuse_session(state, &addr_list, domain_best_pref);
+	} else
+	    sess_count = addr_count = 0;
+
+	/*
+	 * Connect to an SMTP server: create primary MX connections, and
+	 * reuse or create backup MX connections.
+	 * 
+	 * At the start of an SMTP session, all recipients are unmarked. In the
+	 * course of an SMTP session, recipients are marked as KEEP (deliver
+	 * to alternate mail server) or DROP (remove from recipient list). At
+	 * the end of an SMTP session, weed out the recipient list. Unmark
+	 * any left-over recipients and try to deliver them to a backup mail
+	 * server.
+	 * 
+	 * Cache the first good session under the next-hop destination name.
+	 * Cache all good sessions under their physical endpoint.
+	 * 
+	 * Don't query the session cache for primary MX hosts. We already did
+	 * that in smtp_reuse_session(), and if any were found in the cache,
+	 * they were already deleted from the address list.
+	 * 
+	 * Currently, we use smtp_reuse_addr() only for SASL-unauthenticated
+	 * connections. Furthermore, we rely on smtp_reuse_addr() to look up
+	 * an existing SASL-unauthenticated connection only when a new
+	 * connection would be guaranteed not to require SASL authentication.
+	 * 
+	 * In addition, we rely on smtp_reuse_addr() to look up an existing
+	 * plaintext connection only when a new connection would be
+	 * guaranteed not to use TLS.
+	 */
+	for (addr = addr_list; SMTP_RCPT_LEFT(state) > 0 && addr; addr = next) {
+	    next = addr->next;
+	    if (++addr_count == var_smtp_mxaddr_limit)
+		next = 0;
+	    if (dns_rr_to_pa(addr, &hostaddr) == 0) {
+		msg_warn("cannot convert type %s record to printable address",
+			 dns_strtype(addr->type));
+		/* XXX Assume there is no code at the end of this loop. */
+		continue;
+	    }
+	    vstring_strcpy(iter->addr, hostaddr.buf);
+	    vstring_strcpy(iter->host, SMTP_HNAME(addr));
+	    iter->rr = addr;
+#ifdef USE_TLS
+	    if (!smtp_tls_policy_cache_query(why, state->tls, iter)) {
+		msg_warn("TLS policy lookup for %s/%s: %s",
+			 STR(iter->dest), STR(iter->host), STR(why->reason));
+		continue;
+		/* XXX Assume there is no code at the end of this loop. */
+	    }
+	    if (var_smtp_tls_wrappermode
+		&& state->tls->level < TLS_LEV_ENCRYPT) {
+		msg_warn("%s requires \"%s = encrypt\" (or stronger)",
+		      VAR_LMTP_SMTP(TLS_WRAPPER), VAR_LMTP_SMTP(TLS_LEVEL));
+		continue;
+		/* XXX Assume there is no code at the end of this loop. */
+	    }
+	    /* Disable TLS when retrying after a handshake failure */
+	    if (retry_plain) {
+		state->tls->level = TLS_LEV_NONE;
+		retry_plain = 0;
+	    }
+#endif
+	    if ((state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD) == 0
+		|| addr->pref == domain_best_pref
+		|| !(session = smtp_reuse_addr(state,
+					  SMTP_KEY_MASK_SCACHE_ENDP_LABEL)))
+		session = smtp_connect_addr(iter, why, state->misc_flags);
+	    if ((state->session = session) != 0) {
+		session->state = state;
+#ifdef USE_TLS
+		session->tls_nexthop = domain;
+#endif
+		if (addr->pref == domain_best_pref)
+		    session->features |= SMTP_FEATURE_BEST_MX;
+		/* Don't count handshake errors towards the session limit. */
+		if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP)
+		    && next == 0)
+		    state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER;
+		if ((session->features & SMTP_FEATURE_FROM_CACHE) == 0
+		    && smtp_helo(state) != 0) {
+#ifdef USE_TLS
+
+		    /*
+		     * When an opportunistic TLS handshake fails, try the
+		     * same address again, with TLS disabled. See also the
+		     * RETRY_AS_PLAINTEXT macro.
+		     */
+		    if ((retry_plain = session->tls_retry_plain) != 0) {
+			--addr_count;
+			next = addr;
+		    }
+#endif
+
+		    /*
+		     * When a TLS handshake fails, the stream is marked
+		     * "dead" to avoid further I/O over a broken channel.
+		     */
+		    if (!THIS_SESSION_IS_FORBIDDEN
+			&& vstream_ferror(session->stream) == 0
+			&& vstream_feof(session->stream) == 0)
+			smtp_quit(state);
+		} else {
+		    /* Do count delivery errors towards the session limit. */
+		    if (++sess_count == var_smtp_mxsess_limit)
+			next = 0;
+		    if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP)
+			&& next == 0)
+			state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER;
+		    smtp_xfer(state);
+#ifdef USE_TLS
+
+		    /*
+		     * When opportunistic TLS fails after the STARTTLS
+		     * handshake, try the same address again, with TLS
+		     * disabled. See also the RETRY_AS_PLAINTEXT macro.
+		     */
+		    if ((retry_plain = session->tls_retry_plain) != 0) {
+			--sess_count;
+			--addr_count;
+			next = addr;
+		    }
+#endif
+		}
+		smtp_cleanup_session(state);
+	    } else {
+		/* The reason already includes the IP address and TCP port. */
+		msg_info("%s", STR(why->reason));
+	    }
+	    /* XXX Code above assumes there is no code at this loop ending. */
+	}
+	dns_rr_free(addr_list);
+	if (iter->mx) {
+	    dns_rr_free(iter->mx);
+	    iter->mx = 0;			/* Just in case */
+	}
+	myfree(dest_buf);
+	if (state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP)
+	    break;
+    }
+
+    /*
+     * We still need to deliver, bounce or defer some left-over recipients:
+     * either mail loops or some backup mail server was unavailable.
+     */
+    if (SMTP_RCPT_LEFT(state) > 0) {
+
+	/*
+	 * In case of a "no error" indication we make up an excuse: we did
+	 * find the host address, but we did not attempt to connect to it.
+	 * This can happen when the fall-back relay was already tried via a
+	 * cached connection, so that the address list scrubber left behind
+	 * an empty list.
+	 */
+	if (!SMTP_HAS_DSN(why)) {
+	    dsb_simple(why, "4.3.0",
+		       "server unavailable or unable to receive mail");
+	}
+
+	/*
+	 * Pay attention to what could be configuration problems, and pretend
+	 * that these are recoverable rather than bouncing the mail.
+	 */
+	else if (!SMTP_HAS_SOFT_DSN(why)) {
+
+	    /*
+	     * The fall-back destination did not resolve as expected, or it
+	     * is refusing to talk to us, or mail for it loops back to us.
+	     */
+	    if (IS_FALLBACK_RELAY(cpp, sites, non_fallback_sites)) {
+		msg_warn("%s configuration problem", VAR_SMTP_FALLBACK);
+		vstring_strcpy(why->status, "4.3.5");
+		/* XXX Keep the diagnostic code and MTA. */
+	    }
+
+	    /*
+	     * The next-hop relayhost did not resolve as expected, or it is
+	     * refusing to talk to us, or mail for it loops back to us.
+	     * 
+	     * XXX There is no equivalent safety net for mis-configured
+	     * sender-dependent relay hosts. The trivial-rewrite resolver
+	     * would have to flag the result, and the queue manager would
+	     * have to provide that information to delivery agents.
+	     */
+	    else if (smtp_mode && strcmp(sites->argv[0], var_relayhost) == 0) {
+		msg_warn("%s configuration problem", VAR_RELAYHOST);
+		vstring_strcpy(why->status, "4.3.5");
+		/* XXX Keep the diagnostic code and MTA. */
+	    }
+
+	    /*
+	     * Mail for the next-hop destination loops back to myself. Pass
+	     * the mail to the best_mx_transport or bounce it.
+	     */
+	    else if (smtp_mode && SMTP_HAS_LOOP_DSN(why) && *var_bestmx_transp) {
+		dsb_reset(why);			/* XXX */
+		state->status = deliver_pass_all(MAIL_CLASS_PRIVATE,
+						 var_bestmx_transp,
+						 request);
+		SMTP_RCPT_LEFT(state) = 0;	/* XXX */
+	    }
+	}
+    }
+
+    /*
+     * Cleanup.
+     */
+    if (HAVE_SCACHE_REQUEST_NEXTHOP(state))
+	CLEAR_SCACHE_REQUEST_NEXTHOP(state);
+    argv_free(sites);
+}
+
+/* smtp_connect - establish SMTP connection */
+
+int     smtp_connect(SMTP_STATE *state)
+{
+    DELIVER_REQUEST *request = state->request;
+    char   *destination = request->nexthop;
+
+    /*
+     * All deliveries proceed along the same lines, whether they are over TCP
+     * or UNIX-domain sockets, and whether they use SMTP or LMTP: get a
+     * connection from the cache or create a new connection; deliver mail;
+     * update the connection cache or disconnect.
+     * 
+     * The major differences appear at a higher level: the expansion from
+     * destination to address list, and whether to stop before we reach the
+     * end of that list.
+     */
+
+    /*
+     * With LMTP we have direct-to-host delivery only. The destination may
+     * have multiple IP addresses.
+     */
+    if (!smtp_mode) {
+	if (strncmp(destination, "unix:", 5) == 0) {
+	    smtp_connect_local(state, destination + 5);
+	} else {
+	    if (strncmp(destination, "inet:", 5) == 0)
+		destination += 5;
+	    smtp_connect_inet(state, destination, var_smtp_tcp_port);
+	}
+    }
+
+    /*
+     * XXX We don't add support for "unix:" or "inet:" prefixes in SMTP
+     * destinations, because that would break compatibility with existing
+     * Postfix configurations that have a host with such a name.
+     */
+    else {
+	smtp_connect_inet(state, destination, var_smtp_tcp_port);
+    }
+
+    /*
+     * We still need to bounce or defer some left-over recipients: either
+     * (SMTP) mail loops or some server was unavailable.
+     * 
+     * We could avoid this (and the "final server" complexity) by keeping one
+     * DSN structure per recipient in memory, by updating those in-memory
+     * structures with each delivery attempt, and by always flushing all
+     * deferred recipients at the end. We'd probably still want to bounce
+     * recipients immediately, so we'd end up with another chunk of code for
+     * defer logging only.
+     */
+    if (SMTP_RCPT_LEFT(state) > 0) {
+	state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER;	/* XXX */
+	smtp_sess_fail(state);
+
+	/*
+	 * Sanity check. Don't silently lose recipients.
+	 */
+	smtp_rcpt_cleanup(state);
+	if (SMTP_RCPT_LEFT(state) > 0)
+	    msg_panic("smtp_connect: left-over recipients");
+    }
+    return (state->status);
+}
diff --git a/src/smtp/smtp_key.c b/src/smtp/smtp_key.c
new file mode 100644
index 0000000..643f4db
--- /dev/null
+++ b/src/smtp/smtp_key.c
@@ -0,0 +1,215 @@
+/*++
+/* NAME
+/*	smtp_key 3
+/* SUMMARY
+/*	cache/table lookup key management
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	char	*smtp_key_prefix(buffer, delim_na, iterator, context_flags)
+/*	VSTRING	*buffer;
+/*	const char *delim_na;
+/*	SMTP_ITERATOR *iterator;
+/*	int	context_flags;
+/* DESCRIPTION
+/*	The Postfix SMTP server accesses caches and lookup tables,
+/*	using lookup keys that contain information from various
+/*	contexts: per-server configuration, per-request envelope,
+/*	and results from DNS queries.
+/*
+/*	These lookup keys sometimes share the same context information.
+/*	The primary purpose of this API is to ensure that this
+/*	shared context is used consistently, and that its use is
+/*	made explicit (both are needed to verify that there is no
+/*	false cache sharing).
+/*
+/*	smtp_key_prefix() constructs a lookup key prefix from context
+/*	that may be shared with other lookup keys. The user is free
+/*	to append additional application-specific context. The result
+/*	value is a pointer to the result text.
+/*
+/*	Arguments:
+/* .IP buffer
+/*	Storage for the result.
+/* .IP delim_na
+/*	The field delimiter character, and the optional place holder
+/*	character for a) information that is unavailable, b)
+/*	information that is inapplicable, or c) that would result
+/*	in an empty field.  Key fields that contain "delim_na"
+/*	characters will be base64-encoded.
+/*	Do not specify "delim_na" characters that are part of the
+/*	base64 character set.
+/* .IP iterator
+/*	Information that will be selected by the specified flags.
+/* .IP context_flags
+/*	Bit-wise OR of one or more of the following.
+/* .RS
+/* .IP SMTP_KEY_FLAG_SERVICE
+/*	The global service name. This is a proxy for
+/*	destination-independent and request-independent context.
+/* .IP SMTP_KEY_FLAG_SENDER
+/*	The envelope sender address. This is a proxy for sender-dependent
+/*	context, such as per-sender SASL authentication.
+/* .IP SMTP_KEY_FLAG_REQ_NEXTHOP
+/*	The delivery request nexthop destination, including optional
+/*	[] and :port (the same form that users specify in a SASL
+/*	password or TLS policy lookup table). This is a proxy for
+/*	destination-dependent, but host-independent context.
+/* .IP SMTP_KEY_FLAG_CUR_NEXTHOP
+/*	The current iterator's nexthop destination (delivery request
+/*	nexthop or fallback nexthop, including optional [] and
+/*	:port).
+/* .IP SMTP_KEY_FLAG_HOSTNAME
+/*	The current iterator's remote hostname.
+/* .IP SMTP_KEY_FLAG_ADDR
+/*	The current iterator's remote address.
+/* .IP SMTP_KEY_FLAG_PORT
+/*	The current iterator's remote port.
+/* .RE
+/* DIAGNOSTICS
+/*	Panic: undefined flag or zero flags. Fatal: out of memory.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+#include <netinet/in.h>			/* ntohs() for Solaris or BSD */
+#include <arpa/inet.h>			/* ntohs() for Linux or BSD */
+#include <string.h>
+
+ /*
+  * Utility library.
+  */
+#include <msg.h>
+#include <vstring.h>
+#include <base64_code.h>
+
+ /*
+  * Global library.
+  */
+#include <mail_params.h>
+
+ /*
+  * Application-specific.
+  */
+#include <smtp.h>
+
+ /*
+  * We use a configurable field terminator and optional place holder for data
+  * that is unavailable or inapplicable. We base64-encode content that
+  * contains these characters, and content that needs obfuscation.
+  */
+
+/* smtp_key_append_na - append place-holder key field */
+
+static void smtp_key_append_na(VSTRING *buffer, const char *delim_na)
+{
+    if (delim_na[1] != 0)
+	VSTRING_ADDCH(buffer, delim_na[1]);
+    VSTRING_ADDCH(buffer, delim_na[0]);
+}
+
+/* smtp_key_append_str - append string-valued key field */
+
+static void smtp_key_append_str(VSTRING *buffer, const char *str,
+				        const char *delim_na)
+{
+    if (str == 0 || str[0] == 0) {
+	smtp_key_append_na(buffer, delim_na);
+    } else if (str[strcspn(str, delim_na)] != 0) {
+	base64_encode_opt(buffer, str, strlen(str), BASE64_FLAG_APPEND);
+	VSTRING_ADDCH(buffer, delim_na[0]);
+    } else {
+	vstring_sprintf_append(buffer, "%s%c", str, delim_na[0]);
+    }
+}
+
+/* smtp_key_append_uint - append unsigned-valued key field */
+
+static void smtp_key_append_uint(VSTRING *buffer, unsigned num,
+				         const char *delim_na)
+{
+    vstring_sprintf_append(buffer, "%u%c", num, delim_na[0]);
+}
+
+/* smtp_key_prefix - format common elements in lookup key */
+
+char   *smtp_key_prefix(VSTRING *buffer, const char *delim_na,
+			        SMTP_ITERATOR *iter, int flags)
+{
+    static const char myname[] = "smtp_key_prefix";
+    SMTP_STATE *state = iter->parent;	/* private member */
+
+    /*
+     * Sanity checks.
+     */
+    if (state == 0)
+	msg_panic("%s: no parent state", myname);
+    if (flags & ~SMTP_KEY_MASK_ALL)
+	msg_panic("%s: unknown key flags 0x%x",
+		  myname, flags & ~SMTP_KEY_MASK_ALL);
+    if (flags == 0)
+	msg_panic("%s: zero flags", myname);
+
+    /*
+     * Initialize.
+     */
+    VSTRING_RESET(buffer);
+
+    /*
+     * Per-service and per-request context.
+     */
+    if (flags & SMTP_KEY_FLAG_SERVICE)
+	smtp_key_append_str(buffer, state->service, delim_na);
+    if (flags & SMTP_KEY_FLAG_SENDER)
+	smtp_key_append_str(buffer, state->request->sender, delim_na);
+
+    /*
+     * Per-destination context, non-canonicalized form.
+     */
+    if (flags & SMTP_KEY_FLAG_REQ_NEXTHOP)
+	smtp_key_append_str(buffer, STR(iter->request_nexthop), delim_na);
+    if (flags & SMTP_KEY_FLAG_CUR_NEXTHOP)
+	smtp_key_append_str(buffer, STR(iter->dest), delim_na);
+
+    /*
+     * Per-host context, canonicalized form.
+     */
+    if (flags & SMTP_KEY_FLAG_HOSTNAME)
+	smtp_key_append_str(buffer, STR(iter->host), delim_na);
+    if (flags & SMTP_KEY_FLAG_ADDR)
+	smtp_key_append_str(buffer, STR(iter->addr), delim_na);
+    if (flags & SMTP_KEY_FLAG_PORT)
+	smtp_key_append_uint(buffer, ntohs(iter->port), delim_na);
+
+    /*
+     * Requested TLS level, if applicable. TODO(tlsproxy) should the lookup
+     * engine also try the requested TLS level and 'stronger', in case a
+     * server hosts multiple domains with different TLS requirements?
+     */
+    if (flags & SMTP_KEY_FLAG_TLS_LEVEL)
+#ifdef USE_TLS
+	smtp_key_append_uint(buffer, state->tls->level, delim_na);
+#else
+	smtp_key_append_na(buffer, delim_na);
+#endif
+
+    VSTRING_TERMINATE(buffer);
+
+    return STR(buffer);
+}
diff --git a/src/smtp/smtp_map11.c b/src/smtp/smtp_map11.c
new file mode 100644
index 0000000..bca8641
--- /dev/null
+++ b/src/smtp/smtp_map11.c
@@ -0,0 +1,325 @@
+/*++
+/* NAME
+/*	smtp_map11 3
+/* SUMMARY
+/*	one-to-one address mapping
+/* SYNOPSIS
+/*	#include <smtp.h>
+/*
+/*	int	smtp_map11_internal(addr, maps, propagate)
+/*	VSTRING	*addr;
+/*	MAPS	*maps;
+/*	int	propagate;
+/*
+/*	int	smtp_map11_external(addr, maps, propagate)
+/*	VSTRING	*addr;
+/*	MAPS	*maps;
+/*	int	propagate;
+/*
+/*	int	smtp_map11_tree(tree, maps, propagate)
+/*	TOK822	*tree;
+/*	MAPS	*maps;
+/*	int	propagate;
+/* DESCRIPTION
+/*	This module performs non-recursive one-to-one address mapping.
+/*	An unmatched address extension is propagated when
+/*	\fIpropagate\fR is non-zero.
+/*
+/*	smtp_map11_internal() looks up the RFC 822 internal (unquoted)
+/*	string form of an address in the maps specified via the
+/*	\fImaps\fR argument.
+/*
+/*	smtp_map11_external() is a wrapper around the smtp_map11_internal()
+/*	routine that transforms from external (quoted) string form
+/*	to internal form and back.
+/*
+/*	smtp_map11_tree() is a wrapper around the smtp_map11_internal()
+/*	routine that transforms from internal parse tree form to
+/*	internal form and back.
+/* DIAGNOSTICS
+/*	Table lookup errors are fatal.
+/* SEE ALSO
+/*	mail_addr_map(3) address mappings
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <dict.h>
+#include <argv.h>
+#include <tok822.h>
+
+/* Global library. */
+
+#include <mail_addr_map.h>
+#include <quote_822_local.h>
+
+/* Application-specific. */
+
+#include <smtp.h>
+
+/* smtp_map11_internal - one-to-one table lookups */
+
+int     smtp_map11_internal(VSTRING *addr, MAPS *maps, int propagate)
+{
+    const char *myname = "smtp_map11_internal";
+    ARGV   *new_addr;
+    const char *result;
+
+    if ((new_addr = mail_addr_map_internal(maps, STR(addr), propagate)) != 0) {
+	if (new_addr->argc > 1)
+	    msg_warn("multi-valued %s result for %s", maps->title, STR(addr));
+	result = new_addr->argv[0];
+	if (msg_verbose)
+	    msg_info("%s: %s -> %s", myname, STR(addr), result);
+	vstring_strcpy(addr, result);
+	argv_free(new_addr);
+	return (1);
+    } else {
+	if (maps->error != 0)
+	    msg_fatal("%s map lookup problem for %s", maps->title, STR(addr));
+	if (msg_verbose)
+	    msg_info("%s: %s not found", myname, STR(addr));
+	return (0);
+    }
+}
+
+/* smtp_map11_tree - rewrite address node */
+
+int     smtp_map11_tree(TOK822 *tree, MAPS *maps, int propagate)
+{
+    VSTRING *int_buf = vstring_alloc(100);
+    VSTRING *ext_buf = vstring_alloc(100);
+    int     ret;
+
+    tok822_internalize(int_buf, tree->head, TOK822_STR_DEFL);
+    ret = smtp_map11_internal(int_buf, maps, propagate);
+    tok822_free_tree(tree->head);
+    quote_822_local(ext_buf, STR(int_buf));
+    tree->head = tok822_scan(STR(ext_buf), &tree->tail);
+    vstring_free(int_buf);
+    vstring_free(ext_buf);
+    return (ret);
+}
+
+/* smtp_map11_external - rewrite address external form */
+
+int     smtp_map11_external(VSTRING *addr, MAPS *maps, int propagate)
+{
+    VSTRING *temp = vstring_alloc(100);
+    int     ret;
+
+    unquote_822_local(temp, STR(addr));
+    ret = smtp_map11_internal(temp, maps, propagate);
+    quote_822_local(addr, STR(temp));
+    vstring_free(temp);
+    return (ret);
+}
+
+#ifdef TEST
+#include <ctype.h>
+
+#include <msg_vstream.h>
+#include <readlline.h>
+#include <stringops.h>
+#include <vstring_vstream.h>
+
+#include <canon_addr.h>
+#include <mail_params.h>
+
+/* canon_addr_external - surrogate to avoid trivial-rewrite dependency */
+
+VSTRING *canon_addr_external(VSTRING *result, const char *addr)
+{
+    char   *at;
+
+    vstring_strcpy(result, addr);
+    if ((at = strrchr(addr, '@')) == 0
+	|| (at + 1)[strcspn(at + 1, "\"\\")] != 0)
+	vstring_sprintf_append(result, "@%s", var_myorigin);
+    return (result);
+}
+
+static NORETURN usage(const char *progname)
+{
+    msg_fatal("usage: %s [-v]", progname);
+}
+
+int     main(int argc, char **argv)
+{
+    VSTRING *read_buf = vstring_alloc(100);
+    MAPS   *maps = 0;
+    int     lineno;
+    int     first_line;
+    char   *bp;
+    char   *cmd;
+    VSTRING *addr_buf = vstring_alloc(100);
+    char   *addr_field;
+    char   *res_field;
+    int     ch;
+    int     errs = 0;
+
+    /*
+     * Initialize.
+     */
+    msg_vstream_init(basename(argv[0]), VSTREAM_ERR);
+
+    /*
+     * Parse JCL.
+     */
+    while ((ch = GETOPT(argc, argv, "v")) > 0) {
+	switch (ch) {
+	case 'v':
+	    msg_verbose++;
+	    break;
+	default:
+	    usage(argv[0]);
+	}
+    }
+    if (argc != optind)
+	usage(argv[0]);
+
+    util_utf8_enable = 1;
+    mail_params_init();
+
+    /*
+     * TODO: Data-driven parameter settings.
+     */
+#define UPDATE(var, val) do { myfree(var); var = mystrdup(val); } while (0)
+
+    UPDATE(var_myhostname, "localhost.localdomain");
+    UPDATE(var_mydomain, "localdomain");
+    UPDATE(var_myorigin, "localdomain");
+    UPDATE(var_mydest, "localhost.localdomain");
+    UPDATE(var_rcpt_delim, "+");
+
+    /*
+     * The read-eval-print loop.
+     */
+    while (readllines(read_buf, VSTREAM_IN, &lineno, &first_line)) {
+	bp = STR(read_buf);
+	if (msg_verbose)
+	    msg_info("> %s", bp);
+	if ((cmd = mystrtok(&bp, CHARS_SPACE)) == 0 || *cmd == '#')
+	    continue;
+	while (ISSPACE(*bp))
+	    bp++;
+	if (*bp == 0)
+	    msg_fatal("missing parameter for command %s", cmd);
+
+	/*
+	 * Open maps.
+	 */
+	if (strcmp(cmd, "maps") == 0) {
+	    if (maps)
+		maps_free(maps);
+	    maps = maps_create(bp, bp, DICT_FLAG_FOLD_FIX
+			       | DICT_FLAG_UTF8_REQUEST);
+	    vstream_printf("%s\n", bp);
+	    continue;
+	}
+
+	/*
+	 * Lookup and verify.
+	 */
+	else if (maps != 0 && (strcmp(cmd, "external") == 0
+			       || strcmp(cmd, "internal") == 0
+			       || strcmp(cmd, "tree") == 0)) {
+	    int     have_result = 0;
+
+
+	    /*
+	     * Parse the input and expectations.
+	     */
+	    if ((addr_field = mystrtok(&bp, ":")) == 0)
+		msg_fatal("missing address field");
+	    res_field = mystrtok(&bp, ":");
+	    if (mystrtok(&bp, ":") != 0)
+		msg_fatal("garbage after result field");
+
+	    /*
+	     * Perform the mapping.
+	     */
+	    if (strcmp(cmd, "external") == 0) {
+		vstring_strcpy(addr_buf, addr_field);
+		have_result = smtp_map11_external(addr_buf, maps, 1);
+	    } else if (maps && strcmp(cmd, "internal") == 0) {
+		vstring_strcpy(addr_buf, addr_field);
+		have_result = smtp_map11_internal(addr_buf, maps, 1);
+	    } else if (maps && strcmp(cmd, "tree") == 0) {
+		TOK822 *tree;
+		TOK822 **addr_list;
+		TOK822 **tpp;
+
+		tree = tok822_parse(addr_field);
+		addr_list = tok822_grep(tree, TOK822_ADDR);
+		for (tpp = addr_list; *tpp; tpp++)
+		    have_result |= smtp_map11_tree(tpp[0], maps, 1);
+		myfree((void *) addr_list);
+		if (have_result)
+		    tok822_externalize(addr_buf, tree, TOK822_STR_DEFL);
+		tok822_free_tree(tree);
+	    }
+
+	    /*
+	     * Summarize.
+	     */
+	    vstream_printf("%s:%s -> %s\n",
+			   cmd, addr_field, have_result ?
+			   STR(addr_buf) : maps->error ?
+			   "(error)" : "(no match)");
+	    vstream_fflush(VSTREAM_OUT);
+
+	    /*
+	     * Enforce expectations.
+	     */
+	    if (res_field && have_result) {
+		if (strcmp(res_field, STR(addr_buf)) != 0) {
+		    msg_warn("expect result '%s' but got '%s'",
+			     res_field, STR(addr_buf));
+		    errs = 1;
+		}
+	    } else if (res_field && !have_result) {
+		msg_warn("expect result '%s' but got none", res_field);
+		errs = 1;
+	    } else if (!res_field && have_result) {
+		msg_warn("expected no result but got '%s'", STR(addr_buf));
+		errs = 1;
+	    }
+	    vstream_fflush(VSTREAM_OUT);
+	}
+
+	/*
+	 * Unknown request.
+	 */
+	else {
+	    msg_fatal("bad request: %s", cmd);
+	}
+    }
+    vstring_free(addr_buf);
+    vstring_free(read_buf);
+    maps_free(maps);
+    return (errs != 0);
+}
+
+#endif
diff --git a/src/smtp/smtp_map11.in b/src/smtp/smtp_map11.in
new file mode 100644
index 0000000..242859f
--- /dev/null
+++ b/src/smtp/smtp_map11.in
@@ -0,0 +1,33 @@
+# Table with external-form mapping.
+maps inline:{
+    { foo@example.com = bar@com.example }
+    { bar@example.com = bar }
+    { baz@example.com = @com.example }
+    { splitme@example.com = "split me"@com.example } }
+
+# Tests for external form.
+external foo@example.com:bar@com.example
+external bar@example.com:bar@localdomain
+external baz@example.com:baz@com.example
+external foo@example.net
+external splitme@example.com:"split me"@com.example
+external splitme+ext@example.com:"split me+ext"@com.example
+external "baz+first last"@example.com:"baz+first last"@com.example
+
+# Same tests for tree form.
+tree foo@example.com:bar@com.example
+tree bar@example.com:bar@localdomain
+tree baz@example.com:baz@com.example
+tree foo@example.net
+tree splitme@example.com:"split me"@com.example
+tree splitme+ext@example.com:"split me+ext"@com.example
+tree "baz+first last"@example.com:"baz+first last"@com.example
+
+# Same tests for internal form.
+internal foo@example.com:bar@com.example
+internal bar@example.com:bar@localdomain
+internal baz@example.com:baz@com.example
+internal foo@example.net
+internal splitme@example.com:split me@com.example
+internal splitme+ext@example.com:split me+ext@com.example
+internal baz+first last@example.com:baz+first last@com.example
diff --git a/src/smtp/smtp_map11.ref b/src/smtp/smtp_map11.ref
new file mode 100644
index 0000000..7e6f2ed
--- /dev/null
+++ b/src/smtp/smtp_map11.ref
@@ -0,0 +1,22 @@
+inline:{    { foo@example.com = bar@com.example }    { bar@example.com = bar }    { baz@example.com = @com.example }    { splitme@example.com = "split me"@com.example } }
+external:foo@example.com -> bar@com.example
+external:bar@example.com -> bar@localdomain
+external:baz@example.com -> baz@com.example
+external:foo@example.net -> (no match)
+external:splitme@example.com -> "split me"@com.example
+external:splitme+ext@example.com -> "split me+ext"@com.example
+external:"baz+first last"@example.com -> "baz+first last"@com.example
+tree:foo@example.com -> bar@com.example
+tree:bar@example.com -> bar@localdomain
+tree:baz@example.com -> baz@com.example
+tree:foo@example.net -> (no match)
+tree:splitme@example.com -> "split me"@com.example
+tree:splitme+ext@example.com -> "split me+ext"@com.example
+tree:"baz+first last"@example.com -> "baz+first last"@com.example
+internal:foo@example.com -> bar@com.example
+internal:bar@example.com -> bar@localdomain
+internal:baz@example.com -> baz@com.example
+internal:foo@example.net -> (no match)
+internal:splitme@example.com -> split me@com.example
+internal:splitme+ext@example.com -> split me+ext@com.example
+internal:baz+first last@example.com -> baz+first last@com.example
diff --git a/src/smtp/smtp_misc.c b/src/smtp/smtp_misc.c
new file mode 100644
index 0000000..43a176f
--- /dev/null
+++ b/src/smtp/smtp_misc.c
@@ -0,0 +1,100 @@
+/*++
+/* NAME
+/*	smtp_misc 3
+/* SUMMARY
+/*	SMTP client address rewriting
+/* SYNOPSIS
+/*	#include <smtp_addr.h>
+/*
+/*	void	smtp_rewrite_generic_internal(
+/*	VSTRING *dst,
+/*	const char *src);
+/*
+/*	void	smtp_quote_822_address_flags(
+/*	VSTRING *dst,
+/*	const char *src,
+/*	int flags);
+/*
+/*	void	smtp_quote_821_address(
+/*	VSTRING *dst,
+/*	const char *src);
+/* DESCRIPTION
+/*	smtp_rewrite_generic_internal() rewrites a non-empty address
+/*	if generic mapping is enabled, otherwise copies it literally.
+/*
+/*	smtp_quote_822_address_flags() is a wrapper around
+/*	quote_822_local_flags(), except for the empty address which
+/*	is copied literally.
+/*
+/*	smtp_quote_821_address() is a wrapper around quote_821_local(),
+/*	except for the empty address or with "smtp_quote_rfc821_envelope
+/*	= no"; in those cases the address is copied literally.
+/* DIAGNOSTICS
+/*	Fatal: out of memory.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+
+ /*
+  * Utility library.
+  */
+#include <vstring.h>
+
+ /*
+  * Global library.
+  */
+#include <ext_prop.h>
+#include <mail_params.h>
+#include <quote_821_local.h>
+#include <quote_822_local.h>
+
+ /*
+  * Application-specific.
+  */
+#include <smtp.h>
+
+/* smtp_rewrite_generic_internal - generic non-empty address rewriting */
+
+void    smtp_rewrite_generic_internal(VSTRING *dst, const char *src)
+{
+    vstring_strcpy(dst, src);
+    if (*src && smtp_generic_maps)
+	smtp_map11_internal(dst, smtp_generic_maps,
+			    smtp_ext_prop_mask & EXT_PROP_GENERIC);
+}
+
+/* smtp_quote_822_address_flags - quote non-empty header address */
+
+void    smtp_quote_822_address_flags(VSTRING *dst, const char *src, int flags)
+{
+    if (*src) {
+	quote_822_local_flags(dst, src, flags);
+    } else if (flags & QUOTE_FLAG_APPEND) {
+	vstring_strcat(dst, src);
+    } else {
+	vstring_strcpy(dst, src);
+    }
+}
+
+/* smtp_quote_821_address - quote non-empty envelope address */
+
+void    smtp_quote_821_address(VSTRING *dst, const char *src)
+{
+    if (*src && var_smtp_quote_821_env) {
+	quote_821_local(dst, src);
+    } else {
+	vstring_strcpy(dst, src);
+    }
+}
diff --git a/src/smtp/smtp_params.c b/src/smtp/smtp_params.c
new file mode 100644
index 0000000..561f6a0
--- /dev/null
+++ b/src/smtp/smtp_params.c
@@ -0,0 +1,134 @@
+    static const CONFIG_STR_TABLE smtp_str_table[] = {
+	VAR_NOTIFY_CLASSES, DEF_NOTIFY_CLASSES, &var_notify_classes, 0, 0,
+	VAR_SMTP_FALLBACK, DEF_SMTP_FALLBACK, &var_fallback_relay, 0, 0,
+	VAR_BESTMX_TRANSP, DEF_BESTMX_TRANSP, &var_bestmx_transp, 0, 0,
+	VAR_ERROR_RCPT, DEF_ERROR_RCPT, &var_error_rcpt, 1, 0,
+	VAR_SMTP_SASL_PASSWD, DEF_SMTP_SASL_PASSWD, &var_smtp_sasl_passwd, 0, 0,
+	VAR_SMTP_SASL_OPTS, DEF_SMTP_SASL_OPTS, &var_smtp_sasl_opts, 0, 0,
+	VAR_SMTP_SASL_PATH, DEF_SMTP_SASL_PATH, &var_smtp_sasl_path, 0, 0,
+#ifdef USE_TLS
+	VAR_SMTP_SASL_TLS_OPTS, DEF_SMTP_SASL_TLS_OPTS, &var_smtp_sasl_tls_opts, 0, 0,
+	VAR_SMTP_SASL_TLSV_OPTS, DEF_SMTP_SASL_TLSV_OPTS, &var_smtp_sasl_tlsv_opts, 0, 0,
+	VAR_SMTP_TLS_CHAIN_FILES, DEF_SMTP_TLS_CHAIN_FILES, &var_smtp_tls_chain_files, 0, 0,
+	VAR_SMTP_TLS_CERT_FILE, DEF_SMTP_TLS_CERT_FILE, &var_smtp_tls_cert_file, 0, 0,
+	VAR_SMTP_TLS_KEY_FILE, DEF_SMTP_TLS_KEY_FILE, &var_smtp_tls_key_file, 0, 0,
+	VAR_SMTP_TLS_DCERT_FILE, DEF_SMTP_TLS_DCERT_FILE, &var_smtp_tls_dcert_file, 0, 0,
+	VAR_SMTP_TLS_DKEY_FILE, DEF_SMTP_TLS_DKEY_FILE, &var_smtp_tls_dkey_file, 0, 0,
+	VAR_SMTP_TLS_CA_FILE, DEF_SMTP_TLS_CA_FILE, &var_smtp_tls_CAfile, 0, 0,
+	VAR_SMTP_TLS_CA_PATH, DEF_SMTP_TLS_CA_PATH, &var_smtp_tls_CApath, 0, 0,
+	VAR_SMTP_TLS_MAND_CIPH, DEF_SMTP_TLS_MAND_CIPH, &var_smtp_tls_mand_ciph, 1, 0,
+	VAR_SMTP_TLS_EXCL_CIPH, DEF_SMTP_TLS_EXCL_CIPH, &var_smtp_tls_excl_ciph, 0, 0,
+	VAR_SMTP_TLS_MAND_EXCL, DEF_SMTP_TLS_MAND_EXCL, &var_smtp_tls_mand_excl, 0, 0,
+	VAR_SMTP_TLS_MAND_PROTO, DEF_SMTP_TLS_MAND_PROTO, &var_smtp_tls_mand_proto, 0, 0,
+	VAR_SMTP_TLS_VFY_CMATCH, DEF_SMTP_TLS_VFY_CMATCH, &var_smtp_tls_vfy_cmatch, 1, 0,
+	VAR_SMTP_TLS_SEC_CMATCH, DEF_SMTP_TLS_SEC_CMATCH, &var_smtp_tls_sec_cmatch, 1, 0,
+	VAR_SMTP_TLS_FPT_CMATCH, DEF_SMTP_TLS_FPT_CMATCH, &var_smtp_tls_fpt_cmatch, 0, 0,
+	VAR_SMTP_TLS_FPT_DGST, DEF_SMTP_TLS_FPT_DGST, &var_smtp_tls_fpt_dgst, 1, 0,
+	VAR_SMTP_TLS_TAFILE, DEF_SMTP_TLS_TAFILE, &var_smtp_tls_tafile, 0, 0,
+	VAR_SMTP_TLS_PROTO, DEF_SMTP_TLS_PROTO, &var_smtp_tls_proto, 0, 0,
+	VAR_SMTP_TLS_CIPH, DEF_SMTP_TLS_CIPH, &var_smtp_tls_ciph, 1, 0,
+	VAR_SMTP_TLS_ECCERT_FILE, DEF_SMTP_TLS_ECCERT_FILE, &var_smtp_tls_eccert_file, 0, 0,
+	VAR_SMTP_TLS_ECKEY_FILE, DEF_SMTP_TLS_ECKEY_FILE, &var_smtp_tls_eckey_file, 0, 0,
+	VAR_SMTP_TLS_LOGLEVEL, DEF_SMTP_TLS_LOGLEVEL, &var_smtp_tls_loglevel, 0, 0,
+	VAR_SMTP_TLS_SNI, DEF_SMTP_TLS_SNI, &var_smtp_tls_sni, 0, 0,
+	VAR_SMTP_TLS_INSECURE_MX_POLICY, DEF_SMTP_TLS_INSECURE_MX_POLICY, &var_smtp_tls_insecure_mx_policy, 0, 0,
+#endif
+	VAR_SMTP_SASL_MECHS, DEF_SMTP_SASL_MECHS, &var_smtp_sasl_mechs, 0, 0,
+	VAR_SMTP_SASL_TYPE, DEF_SMTP_SASL_TYPE, &var_smtp_sasl_type, 1, 0,
+	VAR_SMTP_BIND_ADDR, DEF_SMTP_BIND_ADDR, &var_smtp_bind_addr, 0, 0,
+	VAR_SMTP_BIND_ADDR6, DEF_SMTP_BIND_ADDR6, &var_smtp_bind_addr6, 0, 0,
+	VAR_SMTP_VRFY_TGT, DEF_SMTP_VRFY_TGT, &var_smtp_vrfy_tgt, 1, 0,
+	VAR_SMTP_HELO_NAME, DEF_SMTP_HELO_NAME, &var_smtp_helo_name, 1, 0,
+	VAR_SMTP_HOST_LOOKUP, DEF_SMTP_HOST_LOOKUP, &var_smtp_host_lookup, 1, 0,
+	VAR_SMTP_DNS_SUPPORT, DEF_SMTP_DNS_SUPPORT, &var_smtp_dns_support, 0, 0,
+	VAR_SMTP_CACHE_DEST, DEF_SMTP_CACHE_DEST, &var_smtp_cache_dest, 0, 0,
+	VAR_SCACHE_SERVICE, DEF_SCACHE_SERVICE, &var_scache_service, 1, 0,
+	VAR_SMTP_EHLO_DIS_WORDS, DEF_SMTP_EHLO_DIS_WORDS, &var_smtp_ehlo_dis_words, 0, 0,
+	VAR_SMTP_EHLO_DIS_MAPS, DEF_SMTP_EHLO_DIS_MAPS, &var_smtp_ehlo_dis_maps, 0, 0,
+	VAR_SMTP_TLS_PER_SITE, DEF_SMTP_TLS_PER_SITE, &var_smtp_tls_per_site, 0, 0,
+	VAR_SMTP_TLS_LEVEL, DEF_SMTP_TLS_LEVEL, &var_smtp_tls_level, 0, 0,
+	VAR_SMTP_TLS_POLICY, DEF_SMTP_TLS_POLICY, &var_smtp_tls_policy, 0, 0,
+	VAR_PROP_EXTENSION, DEF_PROP_EXTENSION, &var_prop_extension, 0, 0,
+	VAR_SMTP_GENERIC_MAPS, DEF_SMTP_GENERIC_MAPS, &var_smtp_generic_maps, 0, 0,
+	VAR_SMTP_TCP_PORT, DEF_SMTP_TCP_PORT, &var_smtp_tcp_port, 0, 0,
+	VAR_SMTP_PIX_BUG_WORDS, DEF_SMTP_PIX_BUG_WORDS, &var_smtp_pix_bug_words, 0, 0,
+	VAR_SMTP_PIX_BUG_MAPS, DEF_SMTP_PIX_BUG_MAPS, &var_smtp_pix_bug_maps, 0, 0,
+	VAR_SMTP_SASL_AUTH_CACHE_NAME, DEF_SMTP_SASL_AUTH_CACHE_NAME, &var_smtp_sasl_auth_cache_name, 0, 0,
+	VAR_CYRUS_CONF_PATH, DEF_CYRUS_CONF_PATH, &var_cyrus_conf_path, 0, 0,
+	VAR_SMTP_HEAD_CHKS, DEF_SMTP_HEAD_CHKS, &var_smtp_head_chks, 0, 0,
+	VAR_SMTP_MIME_CHKS, DEF_SMTP_MIME_CHKS, &var_smtp_mime_chks, 0, 0,
+	VAR_SMTP_NEST_CHKS, DEF_SMTP_NEST_CHKS, &var_smtp_nest_chks, 0, 0,
+	VAR_SMTP_BODY_CHKS, DEF_SMTP_BODY_CHKS, &var_smtp_body_chks, 0, 0,
+	VAR_SMTP_RESP_FILTER, DEF_SMTP_RESP_FILTER, &var_smtp_resp_filter, 0, 0,
+	VAR_SMTP_ADDR_PREF, DEF_SMTP_ADDR_PREF, &var_smtp_addr_pref, 1, 0,
+	VAR_SMTP_DNS_RES_OPT, DEF_SMTP_DNS_RES_OPT, &var_smtp_dns_res_opt, 0, 0,
+	VAR_SMTP_DSN_FILTER, DEF_SMTP_DSN_FILTER, &var_smtp_dsn_filter, 0, 0,
+	VAR_SMTP_DNS_RE_FILTER, DEF_SMTP_DNS_RE_FILTER, &var_smtp_dns_re_filter, 0, 0,
+	VAR_TLSPROXY_SERVICE, DEF_TLSPROXY_SERVICE, &var_tlsproxy_service, 1, 0,
+	0,
+    };
+    static const CONFIG_TIME_TABLE smtp_time_table[] = {
+	VAR_SMTP_CONN_TMOUT, DEF_SMTP_CONN_TMOUT, &var_smtp_conn_tmout, 0, 0,
+	VAR_SMTP_HELO_TMOUT, DEF_SMTP_HELO_TMOUT, &var_smtp_helo_tmout, 1, 0,
+	VAR_SMTP_XFWD_TMOUT, DEF_SMTP_XFWD_TMOUT, &var_smtp_xfwd_tmout, 1, 0,
+	VAR_SMTP_MAIL_TMOUT, DEF_SMTP_MAIL_TMOUT, &var_smtp_mail_tmout, 1, 0,
+	VAR_SMTP_RCPT_TMOUT, DEF_SMTP_RCPT_TMOUT, &var_smtp_rcpt_tmout, 1, 0,
+	VAR_SMTP_DATA0_TMOUT, DEF_SMTP_DATA0_TMOUT, &var_smtp_data0_tmout, 1, 0,
+	VAR_SMTP_DATA1_TMOUT, DEF_SMTP_DATA1_TMOUT, &var_smtp_data1_tmout, 1, 0,
+	VAR_SMTP_DATA2_TMOUT, DEF_SMTP_DATA2_TMOUT, &var_smtp_data2_tmout, 1, 0,
+	VAR_SMTP_RSET_TMOUT, DEF_SMTP_RSET_TMOUT, &var_smtp_rset_tmout, 1, 0,
+	VAR_SMTP_QUIT_TMOUT, DEF_SMTP_QUIT_TMOUT, &var_smtp_quit_tmout, 1, 0,
+	VAR_SMTP_PIX_THRESH, DEF_SMTP_PIX_THRESH, &var_smtp_pix_thresh, 0, 0,
+	VAR_SMTP_PIX_DELAY, DEF_SMTP_PIX_DELAY, &var_smtp_pix_delay, 1, 0,
+	VAR_QUEUE_RUN_DELAY, DEF_QUEUE_RUN_DELAY, &var_queue_run_delay, 1, 0,
+	VAR_MIN_BACKOFF_TIME, DEF_MIN_BACKOFF_TIME, &var_min_backoff_time, 1, 0,
+	VAR_SMTP_CACHE_CONNT, DEF_SMTP_CACHE_CONNT, &var_smtp_cache_conn, 1, 0,
+	VAR_SMTP_REUSE_TIME, DEF_SMTP_REUSE_TIME, &var_smtp_reuse_time, 1, 0,
+#ifdef USE_TLS
+	VAR_SMTP_STARTTLS_TMOUT, DEF_SMTP_STARTTLS_TMOUT, &var_smtp_starttls_tmout, 1, 0,
+#endif
+	VAR_SCACHE_PROTO_TMOUT, DEF_SCACHE_PROTO_TMOUT, &var_scache_proto_tmout, 1, 0,
+	VAR_SMTP_SASL_AUTH_CACHE_TIME, DEF_SMTP_SASL_AUTH_CACHE_TIME, &var_smtp_sasl_auth_cache_time, 0, 0,
+	0,
+    };
+    static const CONFIG_INT_TABLE smtp_int_table[] = {
+	VAR_SMTP_LINE_LIMIT, DEF_SMTP_LINE_LIMIT, &var_smtp_line_limit, 0, 0,
+	VAR_SMTP_MXADDR_LIMIT, DEF_SMTP_MXADDR_LIMIT, &var_smtp_mxaddr_limit, 0, 0,
+	VAR_SMTP_MXSESS_LIMIT, DEF_SMTP_MXSESS_LIMIT, &var_smtp_mxsess_limit, 0, 0,
+	VAR_SMTP_REUSE_COUNT, DEF_SMTP_REUSE_COUNT, &var_smtp_reuse_count, 0, 0,
+#ifdef USE_TLS
+	VAR_SMTP_TLS_SCERT_VD, DEF_SMTP_TLS_SCERT_VD, &var_smtp_tls_scert_vd, 0, 0,
+#endif
+	0,
+    };
+    static const CONFIG_BOOL_TABLE smtp_bool_table[] = {
+	VAR_SMTP_SKIP_5XX, DEF_SMTP_SKIP_5XX, &var_smtp_skip_5xx_greeting,
+	VAR_IGN_MX_LOOKUP_ERR, DEF_IGN_MX_LOOKUP_ERR, &var_ign_mx_lookup_err,
+	VAR_SMTP_SKIP_QUIT_RESP, DEF_SMTP_SKIP_QUIT_RESP, &var_skip_quit_resp,
+	VAR_SMTP_ALWAYS_EHLO, DEF_SMTP_ALWAYS_EHLO, &var_smtp_always_ehlo,
+	VAR_SMTP_NEVER_EHLO, DEF_SMTP_NEVER_EHLO, &var_smtp_never_ehlo,
+	VAR_SMTP_SASL_ENABLE, DEF_SMTP_SASL_ENABLE, &var_smtp_sasl_enable,
+	VAR_SMTP_RAND_ADDR, DEF_SMTP_RAND_ADDR, &var_smtp_rand_addr,
+	VAR_SMTP_QUOTE_821_ENV, DEF_SMTP_QUOTE_821_ENV, &var_smtp_quote_821_env,
+	VAR_SMTP_DEFER_MXADDR, DEF_SMTP_DEFER_MXADDR, &var_smtp_defer_mxaddr,
+	VAR_SMTP_SEND_XFORWARD, DEF_SMTP_SEND_XFORWARD, &var_smtp_send_xforward,
+	VAR_SMTP_CACHE_DEMAND, DEF_SMTP_CACHE_DEMAND, &var_smtp_cache_demand,
+	VAR_SMTP_USE_TLS, DEF_SMTP_USE_TLS, &var_smtp_use_tls,
+	VAR_SMTP_ENFORCE_TLS, DEF_SMTP_ENFORCE_TLS, &var_smtp_enforce_tls,
+	VAR_SMTP_TLS_CONN_REUSE, DEF_SMTP_TLS_CONN_REUSE, &var_smtp_tls_conn_reuse,
+#ifdef USE_TLS
+	VAR_SMTP_TLS_ENFORCE_PN, DEF_SMTP_TLS_ENFORCE_PN, &var_smtp_tls_enforce_peername,
+	VAR_SMTP_TLS_NOTEOFFER, DEF_SMTP_TLS_NOTEOFFER, &var_smtp_tls_note_starttls_offer,
+	VAR_SMTP_TLS_BLK_EARLY_MAIL_REPLY, DEF_SMTP_TLS_BLK_EARLY_MAIL_REPLY, &var_smtp_tls_blk_early_mail_reply,
+	VAR_SMTP_TLS_FORCE_TLSA, DEF_SMTP_TLS_FORCE_TLSA, &var_smtp_tls_force_tlsa,
+#endif
+	VAR_SMTP_TLS_WRAPPER, DEF_SMTP_TLS_WRAPPER, &var_smtp_tls_wrappermode,
+	VAR_SMTP_SENDER_AUTH, DEF_SMTP_SENDER_AUTH, &var_smtp_sender_auth,
+	VAR_SMTP_CNAME_OVERR, DEF_SMTP_CNAME_OVERR, &var_smtp_cname_overr,
+	VAR_SMTP_SASL_AUTH_SOFT_BOUNCE, DEF_SMTP_SASL_AUTH_SOFT_BOUNCE, &var_smtp_sasl_auth_soft_bounce,
+	VAR_LMTP_ASSUME_FINAL, DEF_LMTP_ASSUME_FINAL, &var_lmtp_assume_final,
+	VAR_SMTP_REC_DEADLINE, DEF_SMTP_REC_DEADLINE, &var_smtp_rec_deadline,
+	VAR_SMTP_DUMMY_MAIL_AUTH, DEF_SMTP_DUMMY_MAIL_AUTH, &var_smtp_dummy_mail_auth,
+	VAR_SMTP_BALANCE_INET_PROTO, DEF_SMTP_BALANCE_INET_PROTO, &var_smtp_balance_inet_proto,
+	0,
+    };
diff --git a/src/smtp/smtp_proto.c b/src/smtp/smtp_proto.c
new file mode 100644
index 0000000..a47861e
--- /dev/null
+++ b/src/smtp/smtp_proto.c
@@ -0,0 +1,2502 @@
+/*++
+/* NAME
+/*	smtp_proto 3
+/* SUMMARY
+/*	client SMTP/LMTP protocol
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	int	smtp_helo(state)
+/*	SMTP_STATE *state;
+/*
+/*	int	smtp_xfer(state)
+/*	SMTP_STATE *state;
+/*
+/*	int	smtp_rset(state)
+/*	SMTP_STATE *state;
+/*
+/*	int	smtp_quit(state)
+/*	SMTP_STATE *state;
+/* DESCRIPTION
+/*	In the subsequent text, SMTP implies LMTP.
+/*	This module implements the client side of the SMTP protocol.
+/*
+/*	smtp_helo() performs the initial handshake with the SMTP server.
+/*	When TLS is enabled, this includes STARTTLS negotiations.
+/*
+/*	smtp_xfer() sends message envelope information followed by the
+/*	message data, and finishes the SMTP conversation. These operations
+/*	are combined in one function, in order to implement SMTP pipelining.
+/*	Recipients are marked as "done" in the mail queue file when
+/*	bounced or delivered. The message delivery status is updated
+/*	accordingly.
+/*
+/*	smtp_rset() sends a single RSET command and waits for the
+/*	response. In case of a negative reply it sets the
+/*	CANT_RSET_THIS_SESSION flag.
+/*
+/*	smtp_quit() sends a single QUIT command and waits for the
+/*	response if configured to do so. It always turns off connection
+/*	caching.
+/* DIAGNOSTICS
+/*	smtp_helo(), smtp_xfer(), smtp_rset() and smtp_quit() return
+/*	0 in case of success, -1 in case of failure. For smtp_xfer(),
+/*	smtp_rset() and smtp_quit(), success means the ability to
+/*	perform an SMTP conversation, not necessarily the ability
+/*	to deliver mail, or the achievement of server happiness.
+/*
+/*	In case of a rejected or failed connection, a connection
+/*	is marked as "bad, do not cache". Otherwise, connection
+/*	caching may be turned off (without being marked "bad") at
+/*	the discretion of the code that implements the individual
+/*	protocol steps.
+/*
+/*	Warnings: corrupt message file. A corrupt message is marked
+/*	as "corrupt" by changing its queue file permissions.
+/* BUGS
+/*	Some SMTP servers will abort when the number of recipients
+/*	for one message exceeds their capacity. This behavior violates
+/*	the SMTP protocol.
+/*	The only way around this is to limit the number of recipients
+/*	per transaction to an artificially-low value.
+/* SEE ALSO
+/*	smtp(3h) internal data structures
+/*	smtp_chat(3) query/reply SMTP support
+/*	smtp_trouble(3) error handlers
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	Pipelining code in cooperation with:
+/*	Jon Ribbens
+/*	Oaktree Internet Solutions Ltd.,
+/*	Internet House,
+/*	Canal Basin,
+/*	Coventry,
+/*	CV1 4LY, United Kingdom.
+/*
+/*	Connection caching in cooperation with:
+/*	Victor Duchovni
+/*	Morgan Stanley
+/*
+/*	TLS support originally by:
+/*	Lutz Jaenicke
+/*	BTU Cottbus
+/*	Allgemeine Elektrotechnik
+/*	Universitaetsplatz 3-4
+/*	D-03044 Cottbus, Germany
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/stat.h>
+#include <sys/socket.h>			/* shutdown(2) */
+#include <netinet/in.h>			/* ntohs() */
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>			/* 44BSD stdarg.h uses abort() */
+#include <stdarg.h>
+#include <time.h>
+
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <vstring_vstream.h>
+#include <stringops.h>
+#include <mymalloc.h>
+#include <iostuff.h>
+#include <split_at.h>
+#include <name_code.h>
+#include <name_mask.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <smtp_stream.h>
+#include <mail_queue.h>
+#include <recipient_list.h>
+#include <deliver_request.h>
+#include <defer.h>
+#include <bounce.h>
+#include <record.h>
+#include <rec_type.h>
+#include <off_cvt.h>
+#include <mark_corrupt.h>
+#include <quote_822_local.h>
+#include <mail_proto.h>
+#include <mime_state.h>
+#include <ehlo_mask.h>
+#include <maps.h>
+#include <tok822.h>
+#include <mail_addr_map.h>
+#include <ext_prop.h>
+#include <namadr_list.h>
+#include <match_parent_style.h>
+#include <lex_822.h>
+#include <dsn_mask.h>
+#include <xtext.h>
+#include <uxtext.h>
+#include <smtputf8.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+ /*
+  * Sender and receiver state. A session does not necessarily go through a
+  * linear progression, but states are guaranteed to not jump backwards.
+  * Normal sessions go from MAIL->RCPT->DATA->DOT->QUIT->LAST. The states
+  * MAIL, RCPT, and DATA may also be followed by ABORT->QUIT->LAST.
+  * 
+  * When connection caching is enabled, the QUIT state is suppressed. Normal
+  * sessions proceed as MAIL->RCPT->DATA->DOT->LAST, while aborted sessions
+  * end with ABORT->LAST. The connection is left open for a limited time. An
+  * RSET probe should be sent before attempting to reuse an open connection
+  * for a new transaction.
+  * 
+  * The code to send an RSET probe is a special case with its own initial state
+  * and with its own dedicated state transitions. The session proceeds as
+  * RSET->LAST. This code is kept inside the main protocol engine for
+  * consistent error handling and error reporting. It is not to be confused
+  * with the code that sends RSET to abort a mail transaction in progress.
+  * 
+  * The code to send QUIT without message delivery transaction jumps into the
+  * main state machine. If this introduces complications, then we should
+  * introduce a second QUIT state with its own dedicated state transitions,
+  * just like we did for RSET probes.
+  * 
+  * By default, the receiver skips the QUIT response. Some SMTP servers
+  * disconnect after responding to ".", and some SMTP servers wait before
+  * responding to QUIT.
+  * 
+  * Client states that are associated with sending mail (up to and including
+  * SMTP_STATE_DOT) must have smaller numerical values than the non-sending
+  * states (SMTP_STATE_ABORT .. SMTP_STATE_LAST).
+  */
+#define SMTP_STATE_XFORWARD_NAME_ADDR 0
+#define SMTP_STATE_XFORWARD_PROTO_HELO 1
+#define SMTP_STATE_MAIL		2
+#define SMTP_STATE_RCPT		3
+#define SMTP_STATE_DATA		4
+#define SMTP_STATE_DOT		5
+#define SMTP_STATE_ABORT	6
+#define SMTP_STATE_RSET		7
+#define SMTP_STATE_QUIT		8
+#define SMTP_STATE_LAST		9
+
+int    *xfer_timeouts[SMTP_STATE_LAST] = {
+    &var_smtp_xfwd_tmout,		/* name/addr */
+    &var_smtp_xfwd_tmout,		/* helo/proto */
+    &var_smtp_mail_tmout,
+    &var_smtp_rcpt_tmout,
+    &var_smtp_data0_tmout,
+    &var_smtp_data2_tmout,
+    &var_smtp_rset_tmout,
+    &var_smtp_rset_tmout,
+    &var_smtp_quit_tmout,
+};
+
+char   *xfer_states[SMTP_STATE_LAST] = {
+    "sending XFORWARD name/address",
+    "sending XFORWARD protocol/helo_name",
+    "sending MAIL FROM",
+    "sending RCPT TO",
+    "sending DATA command",
+    "sending end of data -- message may be sent more than once",
+    "sending final RSET",
+    "sending RSET probe",
+    "sending QUIT",
+};
+
+char   *xfer_request[SMTP_STATE_LAST] = {
+    "XFORWARD name/address command",
+    "XFORWARD helo/protocol command",
+    "MAIL FROM command",
+    "RCPT TO command",
+    "DATA command",
+    "end of DATA command",
+    "final RSET command",
+    "RSET probe",
+    "QUIT command",
+};
+
+ /*
+  * Note: MIME downgrade never happens for mail that must be delivered with
+  * SMTPUTF8 (the sender requested SMTPUTF8, AND the delivery request
+  * involves at least one UTF-8 envelope address or header value.
+  */
+#define SMTP_MIME_DOWNGRADE(session, request) \
+    (var_disable_mime_oconv == 0 \
+     && (session->features & SMTP_FEATURE_8BITMIME) == 0 \
+     && strcmp(request->encoding, MAIL_ATTR_ENC_7BIT) != 0)
+
+#ifdef USE_TLS
+
+static int smtp_start_tls(SMTP_STATE *);
+
+#endif
+
+ /*
+  * Call-back information for header/body checks. We don't provide call-backs
+  * for actions that change the message delivery time or destination.
+  */
+static void smtp_hbc_logger(void *, const char *, const char *, const char *, const char *);
+static void smtp_text_out(void *, int, const char *, ssize_t, off_t);
+
+HBC_CALL_BACKS smtp_hbc_callbacks[1] = {
+    smtp_hbc_logger,
+    smtp_text_out,
+};
+
+static int smtp_vrfy_tgt;
+
+/* smtp_vrfy_init - initialize */
+
+void    smtp_vrfy_init(void)
+{
+    static const NAME_CODE vrfy_init_table[] = {
+	SMTP_VRFY_TGT_RCPT, SMTP_STATE_RCPT,
+	SMTP_VRFY_TGT_DATA, SMTP_STATE_DATA,
+	0,
+    };
+
+    if ((smtp_vrfy_tgt = name_code(vrfy_init_table, NAME_CODE_FLAG_NONE,
+				   var_smtp_vrfy_tgt)) == 0)
+	msg_fatal("bad protocol stage: \"%s = %s\"",
+		  VAR_SMTP_VRFY_TGT, var_smtp_vrfy_tgt);
+}
+
+/* smtp_helo - perform initial handshake with SMTP server */
+
+int     smtp_helo(SMTP_STATE *state)
+{
+    const char *myname = "smtp_helo";
+    SMTP_SESSION *session = state->session;
+    DELIVER_REQUEST *request = state->request;
+    SMTP_ITERATOR *iter = state->iterator;
+    SMTP_RESP *resp;
+    SMTP_RESP fake;
+    int     except;
+    char   *lines;
+    char   *words;
+    char   *word;
+    int     n;
+    static const NAME_CODE xforward_features[] = {
+	XFORWARD_NAME, SMTP_FEATURE_XFORWARD_NAME,
+	XFORWARD_ADDR, SMTP_FEATURE_XFORWARD_ADDR,
+	XFORWARD_PORT, SMTP_FEATURE_XFORWARD_PORT,
+	XFORWARD_PROTO, SMTP_FEATURE_XFORWARD_PROTO,
+	XFORWARD_HELO, SMTP_FEATURE_XFORWARD_HELO,
+	XFORWARD_IDENT, SMTP_FEATURE_XFORWARD_IDENT,
+	XFORWARD_DOMAIN, SMTP_FEATURE_XFORWARD_DOMAIN,
+	0, 0,
+    };
+    const char *ehlo_words;
+    int     discard_mask;
+    static const NAME_MASK pix_bug_table[] = {
+	PIX_BUG_DISABLE_ESMTP, SMTP_FEATURE_PIX_NO_ESMTP,
+	PIX_BUG_DELAY_DOTCRLF, SMTP_FEATURE_PIX_DELAY_DOTCRLF,
+	0,
+    };
+    const char *pix_bug_words;
+    const char *pix_bug_source;
+    int     pix_bug_mask;
+
+#ifdef USE_TLS
+    int     saved_features = session->features;
+    int     tls_helo_status;
+
+#endif
+    const char *NOCLOBBER where;
+
+    /*
+     * Skip the plaintext SMTP handshake when connecting in SMTPS mode.
+     */
+#ifdef USE_TLS
+    if (var_smtp_tls_wrappermode
+	&& (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS) == 0) {
+	/* XXX Mix-up of per-session and per-request flags. */
+	state->misc_flags |= SMTP_MISC_FLAG_IN_STARTTLS;
+	smtp_stream_setup(state->session->stream, var_smtp_starttls_tmout,
+			  var_smtp_rec_deadline);
+	tls_helo_status = smtp_start_tls(state);
+	state->misc_flags &= ~SMTP_MISC_FLAG_IN_STARTTLS;
+	return (tls_helo_status);
+    }
+#endif
+
+    /*
+     * Prepare for disaster.
+     */
+    smtp_stream_setup(state->session->stream, var_smtp_helo_tmout,
+		      var_smtp_rec_deadline);
+    if ((except = vstream_setjmp(state->session->stream)) != 0)
+	return (smtp_stream_except(state, except, where));
+
+    /*
+     * If not recursing after STARTTLS, examine the server greeting banner
+     * and decide if we are going to send EHLO as the next command.
+     */
+    if (var_smtp_tls_wrappermode
+	|| (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS) == 0) {
+
+	/*
+	 * Read and parse the server's SMTP greeting banner.
+	 */
+	where = "receiving the initial server greeting";
+	switch ((resp = smtp_chat_resp(session))->code / 100) {
+	case 2:
+	    break;
+	case 5:
+	    if (var_smtp_skip_5xx_greeting)
+		STR(resp->dsn_buf)[0] = '4';
+	    /* FALLTHROUGH */
+	default:
+	    return (smtp_site_fail(state, STR(iter->host), resp,
+				   "host %s refused to talk to me: %s",
+				   session->namaddr,
+				   translit(resp->str, "\n", " ")));
+	}
+
+	/*
+	 * If the policy table specifies a bogus TLS security level, fail
+	 * now.
+	 */
+#ifdef USE_TLS
+	if (state->tls->level == TLS_LEV_INVALID)
+	    /* Warning is already logged. */
+	    return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				   SMTP_RESP_FAKE(&fake, "4.7.0"),
+				   "client TLS configuration problem"));
+#endif
+
+	/*
+	 * XXX Some PIX firewall versions require flush before ".<CR><LF>" so
+	 * it does not span a packet boundary. This hurts performance so it
+	 * is not on by default.
+	 */
+	if (resp->str[strspn(resp->str, "20 *\t\n")] == 0) {
+	    /* Best effort only. Ignore errors. */
+	    if (smtp_pix_bug_maps != 0
+		&& (pix_bug_words =
+		    maps_find(smtp_pix_bug_maps,
+			      STR(iter->addr), 0)) != 0) {
+		pix_bug_source = VAR_LMTP_SMTP(PIX_BUG_MAPS);
+	    } else {
+		pix_bug_words = var_smtp_pix_bug_words;
+		pix_bug_source = VAR_LMTP_SMTP(PIX_BUG_WORDS);
+	    }
+	    if (*pix_bug_words) {
+		pix_bug_mask = name_mask_opt(pix_bug_source, pix_bug_table,
+					     pix_bug_words,
+				     NAME_MASK_ANY_CASE | NAME_MASK_IGNORE);
+		if ((pix_bug_mask & SMTP_FEATURE_PIX_DELAY_DOTCRLF)
+		    && request->msg_stats.incoming_arrival.tv_sec
+		    > vstream_ftime(state->session->stream) - var_smtp_pix_thresh)
+		    pix_bug_mask &= ~SMTP_FEATURE_PIX_DELAY_DOTCRLF;
+		msg_info("%s: enabling PIX workarounds: %s for %s",
+			 request->queue_id,
+			 str_name_mask("pix workaround bitmask",
+				       pix_bug_table, pix_bug_mask),
+			 session->namaddrport);
+		session->features |= pix_bug_mask;
+	    }
+	}
+
+	/*
+	 * See if we are talking to ourself. This should not be possible with
+	 * the way we implement DNS lookups. However, people are known to
+	 * sometimes screw up the naming service. And, mailer loops are still
+	 * possible when our own mailer routing tables are mis-configured.
+	 */
+	words = resp->str;
+	(void) mystrtok(&words, "- \t\n");
+	for (n = 0; (word = mystrtok(&words, " \t\n")) != 0; n++) {
+	    if (n == 0 && strcasecmp(word, var_myhostname) == 0) {
+		if (state->misc_flags & SMTP_MISC_FLAG_LOOP_DETECT)
+		    msg_warn("host %s greeted me with my own hostname %s",
+			     session->namaddrport, var_myhostname);
+	    } else if (strcasecmp(word, "ESMTP") == 0)
+		session->features |= SMTP_FEATURE_ESMTP;
+	}
+	if (smtp_mode) {
+	    if (var_smtp_always_ehlo
+		&& (session->features & SMTP_FEATURE_PIX_NO_ESMTP) == 0)
+		session->features |= SMTP_FEATURE_ESMTP;
+	    if (var_smtp_never_ehlo
+		|| (session->features & SMTP_FEATURE_PIX_NO_ESMTP) != 0)
+		session->features &= ~SMTP_FEATURE_ESMTP;
+	} else {
+	    session->features |= SMTP_FEATURE_ESMTP;
+	}
+    }
+
+    /*
+     * If recursing after STARTTLS, there is no server greeting banner.
+     * Always send EHLO as the next command.
+     */
+    else {
+	session->features |= SMTP_FEATURE_ESMTP;
+    }
+
+    /*
+     * Return the compliment. Fall back to SMTP if our ESMTP recognition
+     * heuristic failed.
+     */
+    if (smtp_mode) {
+	where = "performing the EHLO handshake";
+	if (session->features & SMTP_FEATURE_ESMTP) {
+	    smtp_chat_cmd(session, "EHLO %s", var_smtp_helo_name);
+	    if ((resp = smtp_chat_resp(session))->code / 100 != 2) {
+		if (resp->code == 421)
+		    return (smtp_site_fail(state, STR(iter->host), resp,
+					"host %s refused to talk to me: %s",
+					   session->namaddr,
+					   translit(resp->str, "\n", " ")));
+		else
+		    session->features &= ~SMTP_FEATURE_ESMTP;
+	    }
+	}
+	if ((session->features & SMTP_FEATURE_ESMTP) == 0) {
+	    where = "performing the HELO handshake";
+	    smtp_chat_cmd(session, "HELO %s", var_smtp_helo_name);
+	    if ((resp = smtp_chat_resp(session))->code / 100 != 2)
+		return (smtp_site_fail(state, STR(iter->host), resp,
+				       "host %s refused to talk to me: %s",
+				       session->namaddr,
+				       translit(resp->str, "\n", " ")));
+	}
+    } else {
+	where = "performing the LHLO handshake";
+	smtp_chat_cmd(session, "LHLO %s", var_smtp_helo_name);
+	if ((resp = smtp_chat_resp(session))->code / 100 != 2)
+	    return (smtp_site_fail(state, STR(iter->host), resp,
+				   "host %s refused to talk to me: %s",
+				   session->namaddr,
+				   translit(resp->str, "\n", " ")));
+    }
+
+    /*
+     * No early returns allowed, to ensure consistent handling of TLS and
+     * SASL policies.
+     */
+    if (session->features & SMTP_FEATURE_ESMTP) {
+
+	/*
+	 * Determine what server EHLO keywords to ignore, typically to avoid
+	 * inter-operability problems.
+	 */
+	if (smtp_ehlo_dis_maps == 0
+	    || (ehlo_words = maps_find(smtp_ehlo_dis_maps,
+				       STR(iter->addr), 0)) == 0)
+	    ehlo_words = var_smtp_ehlo_dis_words;
+	if (smtp_ehlo_dis_maps && smtp_ehlo_dis_maps->error) {
+	    msg_warn("%s: %s map lookup error for %s",
+		     session->state->request->queue_id,
+		     smtp_ehlo_dis_maps->title, STR(iter->addr));
+	    vstream_longjmp(session->stream, SMTP_ERR_DATA);
+	}
+	discard_mask = ehlo_mask(ehlo_words);
+	if (discard_mask && !(discard_mask & EHLO_MASK_SILENT))
+	    msg_info("discarding EHLO keywords: %s",
+		     str_ehlo_mask(discard_mask));
+
+	/*
+	 * Pick up some useful features offered by the SMTP server. XXX Until
+	 * we have a portable routine to convert from string to off_t with
+	 * proper overflow detection, ignore the message size limit
+	 * advertised by the SMTP server. Otherwise, we might do the wrong
+	 * thing when the server advertises a really huge message size limit.
+	 * 
+	 * XXX Allow for "code (SP|-) ehlo-keyword (SP|=) ehlo-param...",
+	 * because MicroSoft implemented AUTH based on an old draft.
+	 */
+	lines = resp->str;
+	for (n = 0; (words = mystrtok(&lines, "\n")) != 0; /* see below */ ) {
+	    if (mystrtok(&words, "- ")
+		&& (word = mystrtok(&words, " \t=")) != 0) {
+		if (n == 0) {
+		    if (session->helo != 0)
+			myfree(session->helo);
+
+		    /*
+		     * XXX: Keep the original case: we don't expect a single
+		     * SMTP server to randomly change the case of its helo
+		     * response. If different capitalization is detected, we
+		     * should assume disjoint TLS caches.
+		     */
+		    session->helo = mystrdup(word);
+		    if (strcasecmp(word, var_myhostname) == 0
+			&& (state->misc_flags & SMTP_MISC_FLAG_LOOP_DETECT) != 0) {
+			msg_warn("host %s replied to HELO/EHLO"
+				 " with my own hostname %s",
+				 session->namaddrport, var_myhostname);
+			if (session->features & SMTP_FEATURE_BEST_MX)
+			    return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+					     SMTP_RESP_FAKE(&fake, "5.4.6"),
+					 "mail for %s loops back to myself",
+						   request->nexthop));
+			else
+			    return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+					     SMTP_RESP_FAKE(&fake, "4.4.6"),
+					 "mail for %s loops back to myself",
+						   request->nexthop));
+		    }
+		} else if (strcasecmp(word, "8BITMIME") == 0) {
+		    if ((discard_mask & EHLO_MASK_8BITMIME) == 0)
+			session->features |= SMTP_FEATURE_8BITMIME;
+		} else if (strcasecmp(word, "PIPELINING") == 0) {
+		    if ((discard_mask & EHLO_MASK_PIPELINING) == 0)
+			session->features |= SMTP_FEATURE_PIPELINING;
+		} else if (strcasecmp(word, "XFORWARD") == 0) {
+		    if ((discard_mask & EHLO_MASK_XFORWARD) == 0)
+			while ((word = mystrtok(&words, " \t")) != 0)
+			    session->features |=
+				name_code(xforward_features,
+					  NAME_CODE_FLAG_NONE, word);
+		} else if (strcasecmp(word, "SIZE") == 0) {
+		    if ((discard_mask & EHLO_MASK_SIZE) == 0) {
+			session->features |= SMTP_FEATURE_SIZE;
+			if ((word = mystrtok(&words, " \t")) != 0) {
+			    if (!alldig(word))
+				msg_warn("bad EHLO SIZE limit \"%s\" from %s",
+					 word, session->namaddrport);
+			    else
+				session->size_limit = off_cvt_string(word);
+			}
+		    }
+#ifdef USE_TLS
+		} else if (strcasecmp(word, "STARTTLS") == 0) {
+		    /* Ignored later if we already sent STARTTLS. */
+		    if ((discard_mask & EHLO_MASK_STARTTLS) == 0)
+			session->features |= SMTP_FEATURE_STARTTLS;
+#endif
+#ifdef USE_SASL_AUTH
+		} else if (var_smtp_sasl_enable
+			   && strcasecmp(word, "AUTH") == 0) {
+		    if ((discard_mask & EHLO_MASK_AUTH) == 0)
+			smtp_sasl_helo_auth(session, words);
+#endif
+		} else if (strcasecmp(word, "DSN") == 0) {
+		    if ((discard_mask & EHLO_MASK_DSN) == 0)
+			session->features |= SMTP_FEATURE_DSN;
+		} else if (strcasecmp(word, "SMTPUTF8") == 0) {
+		    if ((discard_mask & EHLO_MASK_SMTPUTF8) == 0)
+			session->features |= SMTP_FEATURE_SMTPUTF8;
+		}
+		n++;
+	    }
+	}
+    }
+    if (msg_verbose)
+	msg_info("server features: 0x%x size %.0f",
+		 session->features, (double) session->size_limit);
+
+    /*
+     * Decide if this delivery requires SMTPUTF8 server support.
+     * 
+     * For now, we require that the remote SMTP server supports SMTPUTF8 when
+     * the sender requested SMTPUTF8 support.
+     * 
+     * XXX EAI Refine this to: the sender requested SMTPUTF8 support AND the
+     * delivery request involves at least one UTF-8 envelope address or
+     * header value.
+     * 
+     * If the sender requested SMTPUTF8 support but the delivery request
+     * involves no UTF-8 envelope address or header value, then we could
+     * still deliver such mail to a non-SMTPUTF8 server, except that we must
+     * either uxtext-encode ORCPT parameters or not send them. We cannot
+     * encode the ORCPT in xtext, because legacy SMTP requires that the
+     * unencoded address consist entirely of printable (graphic and white
+     * space) characters from the US-ASCII repertoire (RFC 3461 section 4). A
+     * correct uxtext encoder will produce a result that an xtext decoder
+     * will pass through unchanged.
+     * 
+     * XXX Should we try to encode headers with RFC 2047 when delivering to a
+     * non-SMTPUTF8 server? That could make life easier for mailing lists.
+     */
+#define DELIVERY_REQUIRES_SMTPUTF8 \
+	((request->smtputf8 & SMTPUTF8_FLAG_REQUESTED) \
+	&& (request->smtputf8 & ~SMTPUTF8_FLAG_REQUESTED))
+
+    /*
+     * Require that the server supports SMTPUTF8 when delivery requires
+     * SMTPUTF8.
+     * 
+     * Fix 20140706: moved this before negotiating TLS, AUTH, and so on.
+     */
+    if ((session->features & SMTP_FEATURE_SMTPUTF8) == 0
+	&& DELIVERY_REQUIRES_SMTPUTF8)
+	return (smtp_mesg_fail(state, DSN_BY_LOCAL_MTA,
+			       SMTP_RESP_FAKE(&fake, "5.6.7"),
+			       "SMTPUTF8 is required, "
+			       "but was not offered by host %s",
+			       session->namaddr));
+
+    /*
+     * Fix 20140706: don't do silly things when the remote server announces
+     * SMTPUTF8 but not 8BITMIME support. Our primary mission is to deliver
+     * mail, not to force people into compliance.
+     */
+    if ((session->features & SMTP_FEATURE_SMTPUTF8) != 0
+	&& (session->features & SMTP_FEATURE_8BITMIME) == 0) {
+	msg_info("host %s offers SMTPUTF8 support, but not 8BITMIME",
+		 session->namaddr);
+	session->features |= SMTP_FEATURE_8BITMIME;
+    }
+
+    /*
+     * We use SMTP command pipelining if the server said it supported it.
+     * Since we use blocking I/O, RFC 2197 says that we should inspect the
+     * TCP window size and not send more than this amount of information.
+     * Unfortunately this information is unavailable using the sockets
+     * interface. However, we *can* get the TCP send buffer size on the local
+     * TCP/IP stack. We should be able to fill this buffer without being
+     * blocked, and then the kernel will effectively do non-blocking I/O for
+     * us by automatically writing out the contents of its send buffer while
+     * we are reading in the responses. In addition to TCP buffering we have
+     * to be aware of application-level buffering by the vstream module,
+     * which is limited to a couple kbytes.
+     * 
+     * XXX No need to do this before and after STARTTLS, but it's not a big deal
+     * if we do.
+     * 
+     * XXX When TLS is turned on, the SMTP-level writes will be encapsulated as
+     * TLS messages. Thus, the TCP-level payload will be larger than the
+     * SMTP-level payload. This has implications for the PIPELINING engine.
+     * 
+     * To avoid deadlock, the PIPELINING engine needs to request a TCP send
+     * buffer size that can hold the unacknowledged commands plus the TLS
+     * encapsulation overhead.
+     * 
+     * The PIPELINING engine keeps the unacknowledged command size <= the
+     * default VSTREAM buffer size (to avoid small-write performance issues
+     * when the VSTREAM buffer size is at its default size). With a default
+     * VSTREAM buffer size of 4096 there is no reason to increase the
+     * unacknowledged command size as the TCP MSS increases. It's safer to
+     * spread the remote SMTP server's recipient processing load over time,
+     * than dumping a very large recipient list all at once.
+     * 
+     * For TLS encapsulation overhead we make a conservative guess: take the
+     * current protocol overhead of ~40 bytes, double the number for future
+     * proofing (~80 bytes), then round up the result to the nearest power of
+     * 2 (128 bytes). Plus, be prepared for worst-case compression that
+     * expands data by 1 kbyte, so that the worst-case SMTP payload per TLS
+     * message becomes 15 kbytes.
+     */
+#define PIPELINING_BUFSIZE	VSTREAM_BUFSIZE
+#ifdef USE_TLS
+#define TLS_WORST_PAYLOAD	16384
+#define TLS_WORST_COMP_OVERHD	1024
+#define TLS_WORST_PROTO_OVERHD	128
+#define TLS_WORST_SMTP_PAYLOAD	(TLS_WORST_PAYLOAD - TLS_WORST_COMP_OVERHD)
+#define TLS_WORST_TOTAL_OVERHD	(TLS_WORST_COMP_OVERHD + TLS_WORST_PROTO_OVERHD)
+#endif
+
+    if (session->features & SMTP_FEATURE_PIPELINING) {
+	SOCKOPT_SIZE optlen;
+	int     tcp_bufsize;
+	int     enc_overhead = 0;
+
+	optlen = sizeof(tcp_bufsize);
+	if (getsockopt(vstream_fileno(session->stream), SOL_SOCKET,
+		       SO_SNDBUF, (char *) &tcp_bufsize, &optlen) < 0)
+	    msg_fatal("%s: getsockopt: %m", myname);
+#ifdef USE_TLS
+	if (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS)
+	    enc_overhead +=
+		(1 + (PIPELINING_BUFSIZE - 1)
+		 / TLS_WORST_SMTP_PAYLOAD) * TLS_WORST_TOTAL_OVERHD;
+#endif
+	if (tcp_bufsize < PIPELINING_BUFSIZE + enc_overhead) {
+	    tcp_bufsize = PIPELINING_BUFSIZE + enc_overhead;
+	    if (setsockopt(vstream_fileno(session->stream), SOL_SOCKET,
+			   SO_SNDBUF, (char *) &tcp_bufsize, optlen) < 0)
+		msg_fatal("%s: setsockopt: %m", myname);
+	}
+	if (msg_verbose)
+	    msg_info("Using %s PIPELINING, TCP send buffer size is %d, "
+		     "PIPELINING buffer size is %d",
+		     smtp_mode ? "ESMTP" : "LMTP",
+		     tcp_bufsize, PIPELINING_BUFSIZE);
+    }
+#ifdef USE_TLS
+
+    /*
+     * Skip this part if we already sent STARTTLS.
+     */
+    if ((state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS) == 0) {
+
+	/*
+	 * Optionally log unused STARTTLS opportunities.
+	 */
+	if ((session->features & SMTP_FEATURE_STARTTLS) &&
+	    var_smtp_tls_note_starttls_offer &&
+	    state->tls->level <= TLS_LEV_NONE)
+	    msg_info("Host offered STARTTLS: [%s]", STR(iter->host));
+
+	/*
+	 * Decide whether or not to send STARTTLS.
+	 */
+	if ((session->features & SMTP_FEATURE_STARTTLS) != 0
+	    && smtp_tls_ctx != 0 && state->tls->level >= TLS_LEV_MAY) {
+
+	    /*
+	     * Prepare for disaster.
+	     */
+	    smtp_stream_setup(state->session->stream, var_smtp_starttls_tmout,
+			      var_smtp_rec_deadline);
+	    if ((except = vstream_setjmp(state->session->stream)) != 0)
+		return (smtp_stream_except(state, except,
+					"receiving the STARTTLS response"));
+
+	    /*
+	     * Send STARTTLS. Recurse when the server accepts STARTTLS, after
+	     * resetting the SASL and EHLO features lists.
+	     * 
+	     * Reset the SASL mechanism list to avoid spurious warnings.
+	     * 
+	     * Use the smtp_sasl_tls_security_options feature to allow SASL
+	     * mechanisms that may not be allowed with plain-text
+	     * connections.
+	     */
+	    smtp_chat_cmd(session, "STARTTLS");
+	    if ((resp = smtp_chat_resp(session))->code / 100 == 2) {
+#ifdef USE_SASL_AUTH
+		if (session->features & SMTP_FEATURE_AUTH)
+		    smtp_sasl_cleanup(session);
+#endif
+		session->features = saved_features;
+		/* XXX Mix-up of per-session and per-request flags. */
+		state->misc_flags |= SMTP_MISC_FLAG_IN_STARTTLS;
+		tls_helo_status = smtp_start_tls(state);
+		state->misc_flags &= ~SMTP_MISC_FLAG_IN_STARTTLS;
+		return (tls_helo_status);
+	    }
+
+	    /*
+	     * Give up if we must use TLS but the server rejects STARTTLS
+	     * although support for it was announced in the EHLO response.
+	     */
+	    session->features &= ~SMTP_FEATURE_STARTTLS;
+	    if (TLS_REQUIRED(state->tls->level))
+		return (smtp_site_fail(state, STR(iter->host), resp,
+		    "TLS is required, but host %s refused to start TLS: %s",
+				       session->namaddr,
+				       translit(resp->str, "\n", " ")));
+	    /* Else try to continue in plain-text mode. */
+	}
+
+	/*
+	 * Give up if we must use TLS but can't for various reasons.
+	 * 
+	 * 200412 Be sure to provide the default clause at the bottom of this
+	 * block. When TLS is required we must never, ever, end up in
+	 * plain-text mode.
+	 */
+	if (TLS_REQUIRED(state->tls->level)) {
+	    if (!(session->features & SMTP_FEATURE_STARTTLS)) {
+		return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				       SMTP_RESP_FAKE(&fake, "4.7.4"),
+			  "TLS is required, but was not offered by host %s",
+				       session->namaddr));
+	    } else if (smtp_tls_ctx == 0) {
+		return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				       SMTP_RESP_FAKE(&fake, "4.7.5"),
+		     "TLS is required, but our TLS engine is unavailable"));
+	    } else {
+		msg_warn("%s: TLS is required but unavailable, don't know why",
+			 myname);
+		return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				       SMTP_RESP_FAKE(&fake, "4.7.0"),
+				       "TLS is required, but unavailable"));
+	    }
+	}
+    }
+#endif
+#ifdef USE_SASL_AUTH
+    if (var_smtp_sasl_enable && (session->features & SMTP_FEATURE_AUTH))
+	return (smtp_sasl_helo_login(state));
+#endif
+
+    return (0);
+}
+
+#ifdef USE_TLS
+
+/* smtp_start_tls - turn on TLS and recurse into the HELO dialog */
+
+static int smtp_start_tls(SMTP_STATE *state)
+{
+    SMTP_SESSION *session = state->session;
+    SMTP_ITERATOR *iter = state->iterator;
+    TLS_CLIENT_START_PROPS start_props;
+    VSTRING *serverid;
+    SMTP_RESP fake;
+    TLS_CLIENT_INIT_PROPS init_props;
+    VSTREAM *tlsproxy;
+    VSTRING *port_buf;
+
+    /*
+     * When the TLS handshake succeeds, we can reuse a connection only if TLS
+     * remains turned on for the lifetime of that connection. This requires
+     * that the TLS library state is maintained in some proxy process, for
+     * example, in tlsproxy(8). We then store the proxy file handle in the
+     * connection cache, and reuse that file handle.
+     * 
+     * Otherwise, we must turn off connection caching. We can't turn off TLS in
+     * one SMTP client process, save the open connection to a cache which is
+     * shared with all SMTP clients, migrate the connection to another SMTP
+     * client, and resume TLS there. When the TLS handshake fails, we can't
+     * reuse the SMTP connection either, because the conversation is in an
+     * unknown state.
+     */
+    if (state->tls->conn_reuse == 0)
+	DONT_CACHE_THIS_SESSION;
+
+    /*
+     * The following assumes sites that use TLS in a perverse configuration:
+     * multiple hosts per hostname, or even multiple hosts per IP address.
+     * All this without a shared TLS session cache, and they still want to
+     * use TLS session caching???
+     * 
+     * The TLS session cache records the trust chain verification status of
+     * cached sessions. Different transports may have different CAfile or
+     * CApath settings, perhaps to allow authenticated connections to sites
+     * with private CA certs without trusting said private certs for other
+     * sites. So we cannot assume that a trust chain valid for one transport
+     * is valid for another. Therefore the client session id must include
+     * either the transport name or the values of CAfile and CApath. We use
+     * the transport name.
+     * 
+     * XXX: We store only one session per lookup key. Ideally the the key maps
+     * 1-to-1 to a server TLS session cache. We use the IP address, port and
+     * ehlo response name to build a lookup key that works for split caches
+     * (that announce distinct names) behind a load balancer.
+     * 
+     * XXX: The TLS library will salt the serverid with further details of the
+     * protocol and cipher requirements including the server ehlo response.
+     * Deferring the helo to the digested suffix results in more predictable
+     * SSL session lookup key lengths.
+     */
+    serverid = vstring_alloc(10);
+    smtp_key_prefix(serverid, "&", state->iterator, SMTP_KEY_FLAG_SERVICE
+		    | SMTP_KEY_FLAG_CUR_NEXTHOP	/* With port */
+		    | SMTP_KEY_FLAG_HOSTNAME
+		    | SMTP_KEY_FLAG_ADDR);
+
+    if (state->tls->conn_reuse) {
+	TLS_CLIENT_PARAMS tls_params;
+
+	/*
+	 * Send all our wishes in one big request.
+	 */
+	TLS_PROXY_CLIENT_INIT_PROPS(&init_props,
+				    log_param = VAR_LMTP_SMTP(TLS_LOGLEVEL),
+				    log_level = var_smtp_tls_loglevel,
+				    verifydepth = var_smtp_tls_scert_vd,
+				    cache_type
+				    = LMTP_SMTP_SUFFIX(TLS_MGR_SCACHE),
+				    chain_files = var_smtp_tls_chain_files,
+				    cert_file = var_smtp_tls_cert_file,
+				    key_file = var_smtp_tls_key_file,
+				    dcert_file = var_smtp_tls_dcert_file,
+				    dkey_file = var_smtp_tls_dkey_file,
+				    eccert_file = var_smtp_tls_eccert_file,
+				    eckey_file = var_smtp_tls_eckey_file,
+				    CAfile = var_smtp_tls_CAfile,
+				    CApath = var_smtp_tls_CApath,
+				    mdalg = var_smtp_tls_fpt_dgst);
+	TLS_PROXY_CLIENT_START_PROPS(&start_props,
+				     timeout = var_smtp_starttls_tmout,
+				     tls_level = state->tls->level,
+				     nexthop = session->tls_nexthop,
+				     host = STR(iter->host),
+				     namaddr = session->namaddrport,
+				     sni = state->tls->sni,
+				     serverid = vstring_str(serverid),
+				     helo = session->helo,
+				     protocols = state->tls->protocols,
+				     cipher_grade = state->tls->grade,
+				     cipher_exclusions
+				     = vstring_str(state->tls->exclusions),
+				     matchargv = state->tls->matchargv,
+				     mdalg = var_smtp_tls_fpt_dgst,
+				     dane = state->tls->dane);
+
+	/*
+	 * The tlsproxy(8) server enforces timeouts that are larger than
+	 * those specified by the tlsproxy(8) client. These timeouts are a
+	 * safety net for the case that the tlsproxy(8) client fails to
+	 * enforce time limits. Normally, the tlsproxy(8) client would time
+	 * out and trigger a plaintext event in the tlsproxy(8) server, and
+	 * cause it to tear down the session.
+	 * 
+	 * However, the tlsproxy(8) server has no insight into the SMTP
+	 * protocol, and therefore it cannot by itself support different
+	 * timeouts at different SMTP protocol stages. Instead, we specify
+	 * the largest timeout (end-of-data) and rely on the SMTP client to
+	 * time out first, which normally results in a plaintext event in the
+	 * tlsproxy(8) server. Unfortunately, we cannot permit plaintext
+	 * events during the TLS handshake, so we specify a separate timeout
+	 * for that stage (the end-of-data timeout would be unreasonably
+	 * large anyway).
+	 */
+#define PROXY_OPEN_FLAGS \
+        (TLS_PROXY_FLAG_ROLE_CLIENT | TLS_PROXY_FLAG_SEND_CONTEXT)
+
+	port_buf = vstring_alloc(100);		/* minimize fragmentation */
+	vstring_sprintf(port_buf, "%d", ntohs(iter->port));
+	tlsproxy =
+	    tls_proxy_open(var_tlsproxy_service, PROXY_OPEN_FLAGS,
+			   session->stream, STR(iter->addr),
+			   STR(port_buf), var_smtp_starttls_tmout,
+			   var_smtp_data2_tmout, state->service,
+			   tls_proxy_client_param_from_config(&tls_params),
+			   &init_props, &start_props);
+	vstring_free(port_buf);
+
+	/*
+	 * To insert tlsproxy(8) between this process and the remote SMTP
+	 * server, we swap the file descriptors between the tlsproxy and
+	 * session->stream VSTREAMS, so that we don't lose all the
+	 * user-configurable session->stream attributes (such as longjump
+	 * buffers or timeouts).
+	 * 
+	 * TODO: the tlsproxy RPCs should return more error detail than a "NO"
+	 * result. OTOH, the in-process TLS engine does not return such info
+	 * either.
+	 * 
+	 * If the tlsproxy request fails we do not fall back to the in-process
+	 * TLS stack. Reason: the admin enabled connection reuse to respect
+	 * receiver policy; silently violating such policy would not be
+	 * useful.
+	 * 
+	 * We also don't fall back to the in-process TLS stack under low-traffic
+	 * conditions, to avoid frustrating attempts to debug a problem with
+	 * using the tlsproxy(8) service.
+	 */
+	if (tlsproxy == 0) {
+	    session->tls_context = 0;
+	} else {
+	    vstream_control(tlsproxy,
+			    CA_VSTREAM_CTL_DOUBLE,
+			    CA_VSTREAM_CTL_END);
+	    vstream_control(session->stream,
+			    CA_VSTREAM_CTL_SWAP_FD(tlsproxy),
+			    CA_VSTREAM_CTL_END);
+	    (void) vstream_fclose(tlsproxy);	/* direct-to-server stream! */
+
+	    /*
+	     * There must not be any pending data in the stream buffers
+	     * before we read the TLS context attributes.
+	     */
+	    vstream_fpurge(session->stream, VSTREAM_PURGE_BOTH);
+
+	    /*
+	     * After plumbing the plaintext stream, receive the TLS context
+	     * object. For this we use the same VSTREAM buffer that we also
+	     * use to receive subsequent SMTP commands, therefore we must be
+	     * prepared for the possibility that the remote SMTP server
+	     * starts talking immediately. The tlsproxy implementation sends
+	     * the TLS context before remote content. The attribute protocol
+	     * is robust enough that an adversary cannot insert their own TLS
+	     * context attributes.
+	     */
+	    session->tls_context = tls_proxy_context_receive(session->stream);
+	    if (session->tls_context) {
+		session->features |= SMTP_FEATURE_FROM_PROXY;
+		tls_log_summary(TLS_ROLE_CLIENT, TLS_USAGE_NEW,
+				session->tls_context);
+	    }
+	}
+    } else {					/* state->tls->conn_reuse */
+
+	/*
+	 * As of Postfix 2.5, tls_client_start() tries hard to always
+	 * complete the TLS handshake. It records the verification and match
+	 * status in the resulting TLScontext. It is now up to the
+	 * application to abort the TLS connection if it chooses.
+	 * 
+	 * XXX When tls_client_start() fails then we don't know what state the
+	 * SMTP connection is in, so we give up on this connection even if we
+	 * are not required to use TLS.
+	 * 
+	 * Large parameter lists are error-prone, so we emulate a language
+	 * feature that C does not have natively: named parameter lists.
+	 */
+	session->tls_context =
+	    TLS_CLIENT_START(&start_props,
+			     ctx = smtp_tls_ctx,
+			     stream = session->stream,
+			     fd = -1,
+			     timeout = var_smtp_starttls_tmout,
+			     tls_level = state->tls->level,
+			     nexthop = session->tls_nexthop,
+			     host = STR(iter->host),
+			     namaddr = session->namaddrport,
+			     sni = state->tls->sni,
+			     serverid = vstring_str(serverid),
+			     helo = session->helo,
+			     protocols = state->tls->protocols,
+			     cipher_grade = state->tls->grade,
+			     cipher_exclusions
+			     = vstring_str(state->tls->exclusions),
+			     matchargv = state->tls->matchargv,
+			     mdalg = var_smtp_tls_fpt_dgst,
+			     dane = state->tls->dane);
+
+	/*
+	 * At this point there must not be any pending data in the stream
+	 * buffers.
+	 */
+	vstream_fpurge(session->stream, VSTREAM_PURGE_BOTH);
+    }						/* state->tls->conn_reuse */
+
+    vstring_free(serverid);
+
+    if (session->tls_context == 0) {
+
+	/*
+	 * We must avoid further I/O, the peer is in an undefined state.
+	 */
+	DONT_USE_FORBIDDEN_SESSION;
+
+	/*
+	 * If TLS is optional, try delivery to the same server over a
+	 * plaintext connection. Otherwise we would defer mail forever with
+	 * destinations that have no alternate MX host.
+	 * 
+	 * Don't fall back to plaintext if we were willing to use SASL-over-TLS
+	 * authentication. If the server doesn't announce SASL support over
+	 * plaintext connections, then we don't want delivery to fail with
+	 * "relay access denied".
+	 * 
+	 * If TLS is opportunistic, don't throttle the destination, otherwise if
+	 * the mail is volume is high enough we may have difficulty ever
+	 * draining even the deferred mail, as new mail provides a constant
+	 * stream of negative feedback.
+	 */
+	if (PLAINTEXT_FALLBACK_OK_AFTER_STARTTLS_FAILURE)
+	    RETRY_AS_PLAINTEXT;
+	return (smtp_misc_fail(state, state->tls->level == TLS_LEV_MAY ?
+			       SMTP_NOTHROTTLE : SMTP_THROTTLE,
+			       DSN_BY_LOCAL_MTA,
+			       SMTP_RESP_FAKE(&fake, "4.7.5"),
+			       "Cannot start TLS: handshake failure"));
+    }
+
+    /*
+     * If we are verifying the server certificate and are not happy with the
+     * result, abort the delivery here. We have a usable TLS session with the
+     * server, so no need to disable I/O, ... we can even be polite and send
+     * "QUIT".
+     * 
+     * See src/tls/tls_level.c and src/tls/tls.h. Levels above "encrypt" require
+     * matching.  Levels >= "dane" require CA or DNSSEC trust.
+     * 
+     * When DANE TLSA records specify an end-entity certificate, the trust and
+     * match bits always coincide, but it is fine to report the wrong
+     * end-entity certificate as untrusted rather than unmatched.
+     */
+    if (TLS_MUST_TRUST(state->tls->level))
+	if (!TLS_CERT_IS_TRUSTED(session->tls_context))
+	    return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				   SMTP_RESP_FAKE(&fake, "4.7.5"),
+				   "Server certificate not trusted"));
+    if (TLS_MUST_MATCH(state->tls->level))
+	if (!TLS_CERT_IS_MATCHED(session->tls_context))
+	    return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				   SMTP_RESP_FAKE(&fake, "4.7.5"),
+				   "Server certificate not verified"));
+
+    /*
+     * At this point we have to re-negotiate the "EHLO" to reget the
+     * feature-list.
+     */
+    return (smtp_helo(state));
+}
+
+#endif
+
+/* smtp_hbc_logger - logging call-back for header/body checks */
+
+static void smtp_hbc_logger(void *context, const char *action,
+			            const char *where, const char *content,
+			            const char *text)
+{
+    const SMTP_STATE *state = (SMTP_STATE *) context;
+
+    if (*text) {
+	msg_info("%s: %s: %s %.60s: %s",
+		 state->request->queue_id, action, where, content, text);
+    } else {
+	msg_info("%s: %s: %s %.60s",
+		 state->request->queue_id, action, where, content);
+    }
+}
+
+/* smtp_text_out - output one header/body record */
+
+static void smtp_text_out(void *context, int rec_type,
+			          const char *text, ssize_t len,
+			          off_t unused_offset)
+{
+    SMTP_STATE *state = (SMTP_STATE *) context;
+    SMTP_SESSION *session = state->session;
+    ssize_t data_left;
+    const char *data_start;
+
+    /*
+     * Deal with an impedance mismatch between Postfix queue files (record
+     * length <= $message_line_length_limit) and SMTP (DATA record length <=
+     * $smtp_line_length_limit). The code below does a little too much work
+     * when the SMTP line length limit is disabled, but it avoids code
+     * duplication, and thus, it avoids testing and maintenance problems.
+     */
+    data_left = len;
+    data_start = text;
+    do {
+	if (state->space_left == var_smtp_line_limit
+	    && data_left > 0 && *data_start == '.')
+	    smtp_fputc('.', session->stream);
+	if (var_smtp_line_limit > 0 && data_left >= state->space_left) {
+	    smtp_fputs(data_start, state->space_left, session->stream);
+	    data_start += state->space_left;
+	    data_left -= state->space_left;
+	    state->space_left = var_smtp_line_limit;
+	    if (data_left > 0 || rec_type == REC_TYPE_CONT) {
+		smtp_fputc(' ', session->stream);
+		state->space_left -= 1;
+	    }
+	} else {
+	    if (rec_type == REC_TYPE_CONT) {
+		smtp_fwrite(data_start, data_left, session->stream);
+		state->space_left -= data_left;
+	    } else {
+		smtp_fputs(data_start, data_left, session->stream);
+		state->space_left = var_smtp_line_limit;
+	    }
+	    break;
+	}
+    } while (data_left > 0);
+}
+
+/* smtp_format_out - output one header/body record */
+
+static void PRINTFLIKE(3, 4) smtp_format_out(void *, int, const char *,...);
+
+static void smtp_format_out(void *context, int rec_type, const char *fmt,...)
+{
+    static VSTRING *vp;
+    va_list ap;
+
+    if (vp == 0)
+	vp = vstring_alloc(100);
+    va_start(ap, fmt);
+    vstring_vsprintf(vp, fmt, ap);
+    va_end(ap);
+    smtp_text_out(context, rec_type, vstring_str(vp), VSTRING_LEN(vp), 0);
+}
+
+/* smtp_header_out - output one message header */
+
+static void smtp_header_out(void *context, int unused_header_class,
+			            const HEADER_OPTS *unused_info,
+			            VSTRING *buf, off_t offset)
+{
+    char   *start = vstring_str(buf);
+    char   *line;
+    char   *next_line;
+
+    /*
+     * This code destroys the header. We could try to avoid clobbering it,
+     * but we're not going to use the data any further.
+     */
+    for (line = start; line; line = next_line) {
+	next_line = split_at(line, '\n');
+	smtp_text_out(context, REC_TYPE_NORM, line, next_line ?
+		      next_line - line - 1 : strlen(line), offset);
+    }
+}
+
+/* smtp_header_rewrite - rewrite message header before output */
+
+static void smtp_header_rewrite(void *context, int header_class,
+				        const HEADER_OPTS *header_info,
+				        VSTRING *buf, off_t offset)
+{
+    SMTP_STATE *state = (SMTP_STATE *) context;
+    int     did_rewrite = 0;
+    char   *line;
+    char   *start;
+    char   *next_line;
+    char   *end_line;
+    char   *result;
+
+    /*
+     * Apply optional header filtering.
+     */
+    if (smtp_header_checks) {
+	result = hbc_header_checks(context, smtp_header_checks, header_class,
+				   header_info, buf, offset);
+	if (result == 0)
+	    return;
+	if (result == HBC_CHECKS_STAT_ERROR) {
+	    msg_warn("%s: smtp header checks lookup error",
+		     state->request->queue_id);
+	    vstream_longjmp(state->session->stream, SMTP_ERR_DATA);
+	}
+	if (result != STR(buf)) {
+	    vstring_strcpy(buf, result);
+	    myfree(result);
+	}
+    }
+
+    /*
+     * Rewrite primary header addresses that match the smtp_generic_maps. The
+     * cleanup server already enforces that all headers have proper lengths
+     * and that all addresses are in proper form, so we don't have to repeat
+     * that.
+     */
+    if (smtp_generic_maps && header_info && header_class == MIME_HDR_PRIMARY
+	&& (header_info->flags & (HDR_OPT_SENDER | HDR_OPT_RECIP)) != 0) {
+	TOK822 *tree;
+	TOK822 **addr_list;
+	TOK822 **tpp;
+
+	tree = tok822_parse(vstring_str(buf)
+			    + strlen(header_info->name) + 1);
+	addr_list = tok822_grep(tree, TOK822_ADDR);
+	for (tpp = addr_list; *tpp; tpp++)
+	    did_rewrite |= smtp_map11_tree(tpp[0], smtp_generic_maps,
+				     smtp_ext_prop_mask & EXT_PROP_GENERIC);
+	if (did_rewrite) {
+	    vstring_truncate(buf, strlen(header_info->name));
+	    vstring_strcat(buf, ": ");
+	    tok822_externalize(buf, tree, TOK822_STR_HEAD);
+	}
+	myfree((void *) addr_list);
+	tok822_free_tree(tree);
+    }
+
+    /*
+     * Pass through unmodified headers without reconstruction.
+     */
+    if (did_rewrite == 0) {
+	smtp_header_out(context, header_class, header_info, buf, offset);
+	return;
+    }
+
+    /*
+     * A rewritten address list contains one address per line. The code below
+     * replaces newlines by spaces, to fit as many addresses on a line as
+     * possible (without rearranging the order of addresses). Prepending
+     * white space to the beginning of lines is delegated to the output
+     * routine.
+     * 
+     * Code derived from cleanup_fold_header().
+     */
+    for (line = start = vstring_str(buf); line != 0; line = next_line) {
+	end_line = line + strcspn(line, "\n");
+	if (line > start) {
+	    if (end_line - start < 70) {	/* TAB counts as one */
+		line[-1] = ' ';
+	    } else {
+		start = line;
+	    }
+	}
+	next_line = *end_line ? end_line + 1 : 0;
+    }
+
+    /*
+     * Prepend a tab to continued header lines that went through the address
+     * rewriting machinery. Just like smtp_header_out(), this code destroys
+     * the header. We could try to avoid clobbering it, but we're not going
+     * to use the data any further.
+     * 
+     * Code derived from cleanup_out_header().
+     */
+    for (line = start = vstring_str(buf); line != 0; line = next_line) {
+	next_line = split_at(line, '\n');
+	if (line == start || IS_SPACE_TAB(*line)) {
+	    smtp_text_out(state, REC_TYPE_NORM, line, next_line ?
+			  next_line - line - 1 : strlen(line), offset);
+	} else {
+	    smtp_format_out(state, REC_TYPE_NORM, "\t%s", line);
+	}
+    }
+}
+
+/* smtp_body_rewrite - rewrite message body before output */
+
+static void smtp_body_rewrite(void *context, int type,
+			              const char *buf, ssize_t len,
+			              off_t offset)
+{
+    SMTP_STATE *state = (SMTP_STATE *) context;
+    char   *result;
+
+    /*
+     * Apply optional body filtering.
+     */
+    if (smtp_body_checks) {
+	result = hbc_body_checks(context, smtp_body_checks, buf, len, offset);
+	if (result == buf) {
+	    smtp_text_out(state, type, buf, len, offset);
+	} else if (result == HBC_CHECKS_STAT_ERROR) {
+	    msg_warn("%s: smtp body checks lookup error",
+		     state->request->queue_id);
+	    vstream_longjmp(state->session->stream, SMTP_ERR_DATA);
+	} else if (result != 0) {
+	    smtp_text_out(state, type, result, strlen(result), offset);
+	    myfree(result);
+	}
+    }
+}
+
+/* smtp_mime_fail - MIME problem */
+
+static void smtp_mime_fail(SMTP_STATE *state, int mime_errs)
+{
+    const MIME_STATE_DETAIL *detail;
+    SMTP_RESP fake;
+
+    detail = mime_state_detail(mime_errs);
+    smtp_mesg_fail(state, DSN_BY_LOCAL_MTA,
+		   SMTP_RESP_FAKE(&fake, detail->dsn),
+		   "%s", detail->text);
+}
+
+/* smtp_out_raw_or_mime - output buffer, raw output or MIME-aware */
+
+static int smtp_out_raw_or_mime(SMTP_STATE *state, int rec_type, VSTRING *buf)
+{
+    SMTP_SESSION *session = state->session;
+    int     mime_errs;
+
+    if (session->mime_state == 0) {
+	smtp_text_out((void *) state, rec_type, vstring_str(buf),
+		      VSTRING_LEN(buf), (off_t) 0);
+    } else {
+	mime_errs =
+	    mime_state_update(session->mime_state, rec_type,
+			      vstring_str(buf), VSTRING_LEN(buf));
+	if (mime_errs) {
+	    smtp_mime_fail(state, mime_errs);
+	    return (-1);
+	}
+    }
+    return (0);
+}
+
+/* smtp_out_add_header - format address header, uses session->scratch* */
+
+static int smtp_out_add_header(SMTP_STATE *state, const char *label,
+			               const char *lt, const char *addr,
+			               const char *gt)
+{
+    SMTP_SESSION *session = state->session;
+
+    smtp_rewrite_generic_internal(session->scratch2, addr);
+    vstring_sprintf(session->scratch, "%s: %s", label, lt);
+    smtp_quote_822_address_flags(session->scratch,
+				 vstring_str(session->scratch2),
+				 QUOTE_FLAG_DEFAULT | QUOTE_FLAG_APPEND);
+    vstring_strcat(session->scratch, gt);
+    return (smtp_out_raw_or_mime(state, REC_TYPE_NORM, session->scratch));
+}
+
+/* smtp_out_add_headers - output additional headers, uses session->scratch* */
+
+static int smtp_out_add_headers(SMTP_STATE *state)
+{
+    if (smtp_cli_attr.flags & SMTP_CLI_FLAG_DELIVERED_TO)
+	if (smtp_out_add_header(state, "Delivered-To", "",
+			   state->request->rcpt_list.info->address, "") < 0)
+	    return (-1);
+    if (smtp_cli_attr.flags & SMTP_CLI_FLAG_ORIG_RCPT)
+	if (smtp_out_add_header(state, "X-Original-To", "",
+			 state->request->rcpt_list.info->orig_addr, "") < 0)
+	    return (-1);
+    if (smtp_cli_attr.flags & SMTP_CLI_FLAG_RETURN_PATH)
+	if (smtp_out_add_header(state, "Return-Path", "<",
+				state->request->sender, ">") < 0)
+	    return (-1);
+    return (0);
+}
+
+/* smtp_loop - exercise the SMTP protocol engine */
+
+static int smtp_loop(SMTP_STATE *state, NOCLOBBER int send_state,
+		             NOCLOBBER int recv_state)
+{
+    const char *myname = "smtp_loop";
+    DELIVER_REQUEST *request = state->request;
+    SMTP_SESSION *session = state->session;
+    SMTP_ITERATOR *iter = state->iterator;
+    SMTP_RESP *resp;
+    RECIPIENT *rcpt;
+    VSTRING *next_command = vstring_alloc(100);
+    int    *NOCLOBBER survivors = 0;
+    NOCLOBBER int next_state;
+    NOCLOBBER int next_rcpt;
+    NOCLOBBER int send_rcpt;
+    NOCLOBBER int recv_rcpt;
+    NOCLOBBER int nrcpt;
+    NOCLOBBER int recv_done;
+    int     except;
+    int     rec_type;
+    NOCLOBBER int prev_type = 0;
+    NOCLOBBER int mail_from_rejected;
+    NOCLOBBER int downgrading;
+    int     mime_errs;
+    SMTP_RESP fake;
+    int     fail_status;
+
+    /* Caution: changes to RETURN() also affect code outside the main loop. */
+
+#define RETURN(x) do { \
+	if (recv_state != SMTP_STATE_LAST) \
+	    DONT_CACHE_THIS_SESSION; \
+	vstring_free(next_command); \
+	if (survivors) \
+	    myfree((void *) survivors); \
+	if (session->mime_state) \
+	    session->mime_state = mime_state_free(session->mime_state); \
+	return (x); \
+    } while (0)
+
+#define SENDER_IS_AHEAD \
+	(recv_state < send_state || recv_rcpt != send_rcpt)
+
+#define SENDER_IN_WAIT_STATE \
+	(send_state == SMTP_STATE_DOT || send_state == SMTP_STATE_LAST)
+
+#define SENDING_MAIL \
+	(recv_state <= SMTP_STATE_DOT)
+
+#define CANT_RSET_THIS_SESSION \
+	(session->features |= SMTP_FEATURE_RSET_REJECTED)
+
+    /*
+     * Pipelining support requires two loops: one loop for sending and one
+     * for receiving. Each loop has its own independent state. Most of the
+     * time the sender can run ahead of the receiver by as much as the TCP
+     * send buffer permits. There are only two places where the sender must
+     * wait for status information from the receiver: once after sending DATA
+     * and once after sending QUIT.
+     * 
+     * The sender state advances until the TCP send buffer would overflow, or
+     * until the sender needs status information from the receiver. At that
+     * point the receiver starts processing responses. Once the receiver has
+     * caught up with the sender, the sender resumes sending commands. If the
+     * receiver detects a serious problem (MAIL FROM rejected, all RCPT TO
+     * commands rejected, DATA rejected) it forces the sender to abort the
+     * SMTP dialog with RSET and QUIT.
+     */
+    nrcpt = 0;
+    next_rcpt = send_rcpt = recv_rcpt = recv_done = 0;
+    mail_from_rejected = 0;
+
+    /*
+     * Prepare for disaster. This should not be needed because the design
+     * guarantees that no output is flushed before smtp_chat_resp() is
+     * called.
+     * 
+     * 1) Every SMTP command fits entirely in a VSTREAM output buffer.
+     * 
+     * 2) smtp_loop() never invokes smtp_chat_cmd() without making sure that
+     * there is sufficient space for the command in the output buffer.
+     * 
+     * 3) smtp_loop() flushes the output buffer to avoid server timeouts.
+     * 
+     * Changing any of these would violate the design, and would likely break
+     * SMTP pipelining.
+     * 
+     * We set up the error handler anyway (only upon entry to avoid wasting
+     * resources) because 1) there is code below that expects that VSTREAM
+     * timeouts are enabled, and 2) this allows us to detect if someone broke
+     * Postfix by introducing spurious flush before read operations.
+     */
+    if (send_state < SMTP_STATE_XFORWARD_NAME_ADDR
+	|| send_state > SMTP_STATE_QUIT)
+	msg_panic("%s: bad sender state %d (receiver state %d)",
+		  myname, send_state, recv_state);
+    smtp_stream_setup(session->stream, *xfer_timeouts[send_state],
+		      var_smtp_rec_deadline);
+    if ((except = vstream_setjmp(session->stream)) != 0) {
+	msg_warn("smtp_proto: spurious flush before read in send state %d",
+		 send_state);
+	RETURN(SENDING_MAIL ? smtp_stream_except(state, except,
+					     xfer_states[send_state]) : -1);
+    }
+
+    /*
+     * The main protocol loop.
+     */
+    do {
+
+	/*
+	 * Build the next command.
+	 */
+	switch (send_state) {
+
+	    /*
+	     * Sanity check.
+	     */
+	default:
+	    msg_panic("%s: bad sender state %d", myname, send_state);
+
+	    /*
+	     * Build the XFORWARD command. With properly sanitized
+	     * information, the command length stays within the 512 byte
+	     * command line length limit.
+	     * 
+	     * XXX smtpd_xforward_preset() initializes some fields as "unknown"
+	     * and some as null; historically, pickup(8) does not send any of
+	     * these, and the queue manager presets absent fields to "not
+	     * available" except for the rewrite context which is preset to
+	     * local by way of migration aid.  These definitions need to be
+	     * centralized for maintainability.
+	     */
+#ifndef CAN_FORWARD_CLIENT_NAME
+#define _ATTR_AVAIL_AND_KNOWN_(val) \
+	(DEL_REQ_ATTR_AVAIL(val) && strcasecmp((val), "unknown"))
+#define CAN_FORWARD_CLIENT_NAME	_ATTR_AVAIL_AND_KNOWN_
+#define CAN_FORWARD_CLIENT_ADDR	_ATTR_AVAIL_AND_KNOWN_
+#define CAN_FORWARD_CLIENT_PORT	_ATTR_AVAIL_AND_KNOWN_
+#define CAN_FORWARD_PROTO_NAME	_ATTR_AVAIL_AND_KNOWN_
+#define CAN_FORWARD_HELO_NAME	DEL_REQ_ATTR_AVAIL
+#define CAN_FORWARD_IDENT_NAME	DEL_REQ_ATTR_AVAIL
+#define CAN_FORWARD_RWR_CONTEXT	DEL_REQ_ATTR_AVAIL
+#endif
+
+	case SMTP_STATE_XFORWARD_NAME_ADDR:
+	    vstring_strcpy(next_command, XFORWARD_CMD);
+	    if ((session->features & SMTP_FEATURE_XFORWARD_NAME)
+		&& CAN_FORWARD_CLIENT_NAME(request->client_name)) {
+		vstring_strcat(next_command, " " XFORWARD_NAME "=");
+		xtext_quote_append(next_command, request->client_name, "");
+	    }
+	    if ((session->features & SMTP_FEATURE_XFORWARD_ADDR)
+		&& CAN_FORWARD_CLIENT_ADDR(request->client_addr)) {
+		vstring_strcat(next_command, " " XFORWARD_ADDR "=");
+		xtext_quote_append(next_command, request->client_addr, "");
+	    }
+	    if ((session->features & SMTP_FEATURE_XFORWARD_PORT)
+		&& CAN_FORWARD_CLIENT_PORT(request->client_port)) {
+		vstring_strcat(next_command, " " XFORWARD_PORT "=");
+		xtext_quote_append(next_command, request->client_port, "");
+	    }
+	    if (session->send_proto_helo)
+		next_state = SMTP_STATE_XFORWARD_PROTO_HELO;
+	    else
+		next_state = SMTP_STATE_MAIL;
+	    break;
+
+	case SMTP_STATE_XFORWARD_PROTO_HELO:
+	    vstring_strcpy(next_command, XFORWARD_CMD);
+	    if ((session->features & SMTP_FEATURE_XFORWARD_PROTO)
+		&& CAN_FORWARD_PROTO_NAME(request->client_proto)) {
+		vstring_strcat(next_command, " " XFORWARD_PROTO "=");
+		xtext_quote_append(next_command, request->client_proto, "");
+	    }
+	    if ((session->features & SMTP_FEATURE_XFORWARD_HELO)
+		&& CAN_FORWARD_HELO_NAME(request->client_helo)) {
+		vstring_strcat(next_command, " " XFORWARD_HELO "=");
+		xtext_quote_append(next_command, request->client_helo, "");
+	    }
+	    if ((session->features & SMTP_FEATURE_XFORWARD_IDENT)
+		&& CAN_FORWARD_IDENT_NAME(request->log_ident)) {
+		vstring_strcat(next_command, " " XFORWARD_IDENT "=");
+		xtext_quote_append(next_command, request->log_ident, "");
+	    }
+	    if ((session->features & SMTP_FEATURE_XFORWARD_DOMAIN)
+		&& CAN_FORWARD_RWR_CONTEXT(request->rewrite_context)) {
+		vstring_strcat(next_command, " " XFORWARD_DOMAIN "=");
+		xtext_quote_append(next_command,
+		     strcmp(request->rewrite_context, MAIL_ATTR_RWR_LOCAL) ?
+			      XFORWARD_DOM_REMOTE : XFORWARD_DOM_LOCAL, "");
+	    }
+	    next_state = SMTP_STATE_MAIL;
+	    break;
+
+	    /*
+	     * Build the MAIL FROM command.
+	     */
+	case SMTP_STATE_MAIL:
+	    request->msg_stats.reuse_count = session->reuse_count;
+	    GETTIMEOFDAY(&request->msg_stats.conn_setup_done);
+	    smtp_rewrite_generic_internal(session->scratch2, request->sender);
+	    smtp_quote_821_address(session->scratch,
+				   vstring_str(session->scratch2));
+	    vstring_sprintf(next_command, "MAIL FROM:<%s>",
+			    vstring_str(session->scratch));
+	    /* XXX Don't announce SIZE if we're going to MIME downgrade. */
+	    if (session->features & SMTP_FEATURE_SIZE	/* RFC 1870 */
+		&& !SMTP_MIME_DOWNGRADE(session, request))
+		vstring_sprintf_append(next_command, " SIZE=%lu",
+				       request->data_size);
+	    if (session->features & SMTP_FEATURE_8BITMIME) {	/* RFC 1652 */
+		if (strcmp(request->encoding, MAIL_ATTR_ENC_8BIT) == 0)
+		    vstring_strcat(next_command, " BODY=8BITMIME");
+		else if (strcmp(request->encoding, MAIL_ATTR_ENC_7BIT) == 0)
+		    vstring_strcat(next_command, " BODY=7BIT");
+		else if (strcmp(request->encoding, MAIL_ATTR_ENC_NONE) != 0)
+		    msg_warn("%s: unknown content encoding: %s",
+			     request->queue_id, request->encoding);
+	    }
+	    if (session->features & SMTP_FEATURE_DSN) {
+		if (request->dsn_envid[0]) {
+		    vstring_sprintf_append(next_command, " ENVID=");
+		    xtext_quote_append(next_command, request->dsn_envid, "+=");
+		}
+		if (request->dsn_ret)
+		    vstring_sprintf_append(next_command, " RET=%s",
+					   dsn_ret_str(request->dsn_ret));
+	    }
+
+	    /*
+	     * Request SMTPUTF8 when the remote SMTP server supports SMTPUTF8
+	     * and the sender requested SMTPUTF8 support.
+	     * 
+	     * If the sender requested SMTPUTF8 but the remote SMTP server does
+	     * not support SMTPUTF8, then we have already determined earlier
+	     * that delivering this message without SMTPUTF8 will not break
+	     * the SMTPUTF8 promise that was made to the sender.
+	     */
+	    if ((session->features & SMTP_FEATURE_SMTPUTF8) != 0
+		&& (request->smtputf8 & SMTPUTF8_FLAG_REQUESTED) != 0)
+		vstring_strcat(next_command, " SMTPUTF8");
+
+	    /*
+	     * We authenticate the local MTA only, but not the sender.
+	     */
+#ifdef USE_SASL_AUTH
+	    if (var_smtp_sasl_enable
+		&& var_smtp_dummy_mail_auth
+		&& (session->features & SMTP_FEATURE_AUTH))
+		vstring_strcat(next_command, " AUTH=<>");
+#endif
+
+	    /*
+	     * CVE-2009-3555 (TLS renegotiation). Try to detect a mail
+	     * hijacking attack that prepends malicious EHLO/MAIL/RCPT/DATA
+	     * commands to our TLS session.
+	     * 
+	     * For the attack to succeed, the remote SMTP server must reply to
+	     * the malicious EHLO/MAIL/RCPT/DATA commands after completing
+	     * TLS (re)negotiation, so that the replies arrive in our TLS
+	     * session (otherwise the Postfix SMTP client would time out
+	     * waiting for an answer). With some luck we can detect this
+	     * specific attack as a server MAIL reply that arrives before we
+	     * send our own MAIL command.
+	     * 
+	     * We don't apply this test to the HELO command because the result
+	     * would be very timing sensitive, and we don't apply this test
+	     * to RCPT and DATA replies because these may be pipelined for
+	     * legitimate reasons.
+	     */
+#ifdef USE_TLS
+	    if (var_smtp_tls_blk_early_mail_reply
+		&& (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS) != 0
+		&& (vstream_peek(session->stream) > 0
+		    || peekfd(vstream_fileno(session->stream)) > 0))
+		session->features |= SMTP_FEATURE_EARLY_TLS_MAIL_REPLY;
+#endif
+
+	    /*
+	     * We now return to our regular broadcast.
+	     */
+	    next_state = SMTP_STATE_RCPT;
+	    break;
+
+	    /*
+	     * Build one RCPT TO command before we have seen the MAIL FROM
+	     * response.
+	     */
+	case SMTP_STATE_RCPT:
+	    rcpt = request->rcpt_list.info + send_rcpt;
+	    smtp_rewrite_generic_internal(session->scratch2, rcpt->address);
+	    smtp_quote_821_address(session->scratch,
+				   vstring_str(session->scratch2));
+	    vstring_sprintf(next_command, "RCPT TO:<%s>",
+			    vstring_str(session->scratch));
+	    if (session->features & SMTP_FEATURE_DSN) {
+		/* XXX DSN xtext encode address value not type. */
+		const char *orcpt_type_addr = rcpt->dsn_orcpt;
+
+		/* Fix 20140706: don't use empty rcpt->orig_addr. */
+		if (orcpt_type_addr[0] == 0 && rcpt->orig_addr[0] != 0) {
+		    quote_822_local(session->scratch, rcpt->orig_addr);
+		    vstring_sprintf(session->scratch2, "%s;%s",
+		    /* Fix 20140707: sender must request SMTPUTF8. */
+				    (request->smtputf8 != 0
+			      && !allascii(vstring_str(session->scratch))) ?
+				    "utf-8" : "rfc822",
+				    vstring_str(session->scratch));
+		    orcpt_type_addr = vstring_str(session->scratch2);
+		}
+		if (orcpt_type_addr[0] != 0) {
+		    /* Fix 20140706: don't send unquoted ORCPT. */
+		    /* Fix 20140707: quoting method must match orcpt type. */
+		    /* Fix 20140707: handle uxtext encoder errors. */
+		    if (strncasecmp(orcpt_type_addr, "utf-8;", 6) == 0) {
+			if (uxtext_quote(session->scratch,
+					 orcpt_type_addr, "+=") != 0)
+			    vstring_sprintf_append(next_command, " ORCPT=%s",
+					     vstring_str(session->scratch));
+		    } else {
+			xtext_quote(session->scratch, orcpt_type_addr, "=");
+			vstring_sprintf_append(next_command, " ORCPT=%s",
+					     vstring_str(session->scratch));
+		    }
+		}
+		if (rcpt->dsn_notify)
+		    vstring_sprintf_append(next_command, " NOTIFY=%s",
+					   dsn_notify_str(rcpt->dsn_notify));
+	    }
+	    if ((next_rcpt = send_rcpt + 1) == SMTP_RCPT_LEFT(state))
+		next_state = (DEL_REQ_TRACE_ONLY(request->flags)
+			      && smtp_vrfy_tgt == SMTP_STATE_RCPT) ?
+		    SMTP_STATE_ABORT : SMTP_STATE_DATA;
+	    break;
+
+	    /*
+	     * Build the DATA command before we have seen all the RCPT TO
+	     * responses.
+	     */
+	case SMTP_STATE_DATA:
+	    vstring_strcpy(next_command, "DATA");
+	    next_state = SMTP_STATE_DOT;
+	    break;
+
+	    /*
+	     * Build the "." command after we have seen the DATA response
+	     * (DATA is a protocol synchronization point).
+	     * 
+	     * Changing the connection caching state here is safe because it
+	     * affects none of the not-yet processed replies to
+	     * already-generated commands.
+	     */
+	case SMTP_STATE_DOT:
+	    vstring_strcpy(next_command, ".");
+	    if (THIS_SESSION_IS_EXPIRED)
+		DONT_CACHE_THIS_SESSION;
+	    next_state = THIS_SESSION_IS_CACHED ?
+		SMTP_STATE_LAST : SMTP_STATE_QUIT;
+	    break;
+
+	    /*
+	     * The SMTP_STATE_ABORT sender state is entered by the sender
+	     * when it has verified all recipients; or it is entered by the
+	     * receiver when all recipients are verified or rejected, and is
+	     * then left before the bottom of the main loop.
+	     * 
+	     * Changing the connection caching state here is safe because there
+	     * are no not-yet processed replies to already-generated
+	     * commands.
+	     */
+	case SMTP_STATE_ABORT:
+	    vstring_strcpy(next_command, "RSET");
+	    if (THIS_SESSION_IS_EXPIRED)
+		DONT_CACHE_THIS_SESSION;
+	    next_state = THIS_SESSION_IS_CACHED ?
+		SMTP_STATE_LAST : SMTP_STATE_QUIT;
+	    break;
+
+	    /*
+	     * Build the RSET command. This is entered as initial state from
+	     * smtp_rset() and has its own dedicated state transitions. It is
+	     * used to find out the status of a cached session before
+	     * attempting mail delivery.
+	     */
+	case SMTP_STATE_RSET:
+	    vstring_strcpy(next_command, "RSET");
+	    next_state = SMTP_STATE_LAST;
+	    break;
+
+	    /*
+	     * Build the QUIT command before we have seen the "." or RSET
+	     * response. This is entered as initial state from smtp_quit(),
+	     * or is reached near the end of any non-cached session.
+	     * 
+	     * Changing the connection caching state here is safe. If this
+	     * command is pipelined together with a preceding command, then
+	     * connection caching was already turned off. Do not clobber the
+	     * "bad connection" flag.
+	     */
+	case SMTP_STATE_QUIT:
+	    vstring_strcpy(next_command, "QUIT");
+	    next_state = SMTP_STATE_LAST;
+	    if (THIS_SESSION_IS_CACHED)
+		DONT_CACHE_THIS_SESSION;
+	    break;
+
+	    /*
+	     * The final sender state has no action associated with it.
+	     */
+	case SMTP_STATE_LAST:
+	    VSTRING_RESET(next_command);
+	    break;
+	}
+	VSTRING_TERMINATE(next_command);
+
+	/*
+	 * Process responses until the receiver has caught up. Vstreams
+	 * automatically flush buffered output when reading new data.
+	 * 
+	 * Flush unsent output if command pipelining is off or if no I/O
+	 * happened for a while. This limits the accumulation of client-side
+	 * delays in pipelined sessions.
+	 * 
+	 * The PIPELINING engine will flush the VSTREAM buffer if the sender
+	 * could otherwise produce more output than fits the PIPELINING
+	 * buffer. This generally works because we know exactly how much
+	 * output we produced since the last time that the sender and
+	 * receiver synchronized the SMTP state. However this logic is not
+	 * applicable after the sender enters the DATA phase, where it does
+	 * not synchronize with the receiver until the <CR><LF>.<CR><LF>.
+	 * Thus, the PIPELINING engine no longer knows how much data is
+	 * pending in the TCP send buffer. For this reason, if PIPELINING is
+	 * enabled, we always pipeline QUIT after <CR><LF>.<CR><LF>. This is
+	 * safe because once the receiver reads <CR><LF>.<CR><LF>, its TCP
+	 * stack either has already received the QUIT<CR><LF>, or else it
+	 * acknowledges all bytes up to and including <CR><LF>.<CR><LF>,
+	 * making room in the sender's TCP stack for QUIT<CR><LF>.
+	 */
+#define CHECK_PIPELINING_BUFSIZE \
+	(recv_state != SMTP_STATE_DOT || send_state != SMTP_STATE_QUIT)
+
+	if (SENDER_IN_WAIT_STATE
+	    || (SENDER_IS_AHEAD
+		&& ((session->features & SMTP_FEATURE_PIPELINING) == 0
+		    || (CHECK_PIPELINING_BUFSIZE
+			&& (VSTRING_LEN(next_command) + 2
+		    + vstream_bufstat(session->stream, VSTREAM_BST_OUT_PEND)
+			    > PIPELINING_BUFSIZE))
+		    || time((time_t *) 0)
+		    - vstream_ftime(session->stream) > 10))) {
+	    while (SENDER_IS_AHEAD) {
+
+		/*
+		 * Sanity check.
+		 */
+		if (recv_state < SMTP_STATE_XFORWARD_NAME_ADDR
+		    || recv_state > SMTP_STATE_QUIT)
+		    msg_panic("%s: bad receiver state %d (sender state %d)",
+			      myname, recv_state, send_state);
+
+		/*
+		 * Receive the next server response. Use the proper timeout,
+		 * and log the proper client state in case of trouble.
+		 * 
+		 * XXX If we lose the connection before sending end-of-data,
+		 * find out if the server sent a premature end-of-data reply.
+		 * If this read attempt fails, report "lost connection while
+		 * sending message body", not "lost connection while sending
+		 * end-of-data".
+		 * 
+		 * "except" becomes zero just above the protocol loop, and stays
+		 * zero or triggers an early return from the loop. In just
+		 * one case: loss of the connection when sending the message
+		 * body, we record the exception, and keep processing in the
+		 * hope of detecting a premature 5XX. We must be careful to
+		 * not clobber this non-zero value once it is set. The
+		 * variable need not survive longjmp() calls, since the only
+		 * setjmp() which does not return early is the one sets this
+		 * condition, subquent failures always return early.
+		 */
+#define LOST_CONNECTION_INSIDE_DATA (except == SMTP_ERR_EOF)
+
+		smtp_stream_setup(session->stream, *xfer_timeouts[recv_state],
+				  var_smtp_rec_deadline);
+		if (LOST_CONNECTION_INSIDE_DATA) {
+		    if (vstream_setjmp(session->stream) != 0)
+			RETURN(smtp_stream_except(state, SMTP_ERR_EOF,
+						  "sending message body"));
+		} else {
+		    if ((except = vstream_setjmp(session->stream)) != 0)
+			RETURN(SENDING_MAIL ? smtp_stream_except(state, except,
+					     xfer_states[recv_state]) : -1);
+		}
+		resp = smtp_chat_resp(session);
+
+		/*
+		 * Process the response.
+		 */
+		switch (recv_state) {
+
+		    /*
+		     * Process the XFORWARD response.
+		     */
+		case SMTP_STATE_XFORWARD_NAME_ADDR:
+		    if (resp->code / 100 != 2)
+			msg_warn("host %s said: %s (in reply to %s)",
+				 session->namaddrport,
+				 translit(resp->str, "\n", " "),
+			       xfer_request[SMTP_STATE_XFORWARD_NAME_ADDR]);
+		    if (session->send_proto_helo)
+			recv_state = SMTP_STATE_XFORWARD_PROTO_HELO;
+		    else
+			recv_state = SMTP_STATE_MAIL;
+		    break;
+
+		case SMTP_STATE_XFORWARD_PROTO_HELO:
+		    if (resp->code / 100 != 2)
+			msg_warn("host %s said: %s (in reply to %s)",
+				 session->namaddrport,
+				 translit(resp->str, "\n", " "),
+			      xfer_request[SMTP_STATE_XFORWARD_PROTO_HELO]);
+		    recv_state = SMTP_STATE_MAIL;
+		    break;
+
+		    /*
+		     * Process the MAIL FROM response. When the server
+		     * rejects the sender, set the mail_from_rejected flag so
+		     * that the receiver may apply a course correction.
+		     */
+		case SMTP_STATE_MAIL:
+		    if (resp->code / 100 != 2) {
+			smtp_mesg_fail(state, STR(iter->host), resp,
+				       "host %s said: %s (in reply to %s)",
+				       session->namaddr,
+				       translit(resp->str, "\n", " "),
+				       xfer_request[SMTP_STATE_MAIL]);
+			mail_from_rejected = 1;
+		    }
+
+		    /*
+		     * CVE-2009-3555 (TLS renegotiation). Whatever it was
+		     * that arrived before we sent our MAIL FROM command, it
+		     * was not a fatal-level TLS alert message. It could be a
+		     * warning-level TLS alert message, or a ChangeCipherSpec
+		     * message, but such messages are not normally sent in
+		     * the middle of a TLS session. We disconnect and try
+		     * again later.
+		     */
+#ifdef USE_TLS
+		    if (var_smtp_tls_blk_early_mail_reply
+			&& (session->features & SMTP_FEATURE_EARLY_TLS_MAIL_REPLY)) {
+			smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+				       SMTP_RESP_FAKE(&fake, "4.7.0"),
+				       "unexpected server message");
+			msg_warn("server %s violates %s policy",
+				 session->namaddr,
+				 VAR_LMTP_SMTP(TLS_BLK_EARLY_MAIL_REPLY));
+			mail_from_rejected = 1;
+		    }
+#endif
+
+		    /*
+		     * We now return to our regular broadcast.
+		     */
+		    recv_state = SMTP_STATE_RCPT;
+		    break;
+
+		    /*
+		     * Process one RCPT TO response. If MAIL FROM was
+		     * rejected, ignore RCPT TO responses: all recipients are
+		     * dead already. When all recipients are rejected the
+		     * receiver may apply a course correction.
+		     * 
+		     * XXX 2821: Section 4.5.3.1 says that a 552 RCPT TO reply
+		     * must be treated as if the server replied with 452.
+		     * However, this causes "too much mail data" to be
+		     * treated as a recoverable error, which is wrong. I'll
+		     * stick with RFC 821.
+		     */
+		case SMTP_STATE_RCPT:
+		    if (!mail_from_rejected) {
+#ifdef notdef
+			if (resp->code == 552) {
+			    resp->code = 452;
+			    resp->dsn[0] = '4';
+			}
+#endif
+			rcpt = request->rcpt_list.info + recv_rcpt;
+			if (resp->code / 100 == 2) {
+			    if (!smtp_mode) {
+				if (survivors == 0)
+				    survivors = (int *)
+					mymalloc(request->rcpt_list.len
+						 * sizeof(int));
+				survivors[nrcpt] = recv_rcpt;
+			    }
+			    ++nrcpt;
+			    /* If trace-only, mark the recipient done. */
+			    if (DEL_REQ_TRACE_ONLY(request->flags)
+				&& smtp_vrfy_tgt == SMTP_STATE_RCPT) {
+				translit(resp->str, "\n", " ");
+				smtp_rcpt_done(state, resp, rcpt);
+			    }
+			} else {
+			    smtp_rcpt_fail(state, rcpt, STR(iter->host), resp,
+					"host %s said: %s (in reply to %s)",
+					   session->namaddr,
+					   translit(resp->str, "\n", " "),
+					   xfer_request[SMTP_STATE_RCPT]);
+			}
+		    }
+		    /* If trace-only, send RSET instead of DATA. */
+		    if (++recv_rcpt == SMTP_RCPT_LEFT(state))
+			recv_state = (DEL_REQ_TRACE_ONLY(request->flags)
+				      && smtp_vrfy_tgt == SMTP_STATE_RCPT) ?
+			    SMTP_STATE_ABORT : SMTP_STATE_DATA;
+		    /* XXX Also: record if non-delivering session. */
+		    break;
+
+		    /*
+		     * Process the DATA response. When the server rejects
+		     * DATA, set nrcpt to a negative value so that the
+		     * receiver can apply a course correction.
+		     */
+		case SMTP_STATE_DATA:
+		    recv_state = SMTP_STATE_DOT;
+		    if (resp->code / 100 != 3) {
+			if (nrcpt > 0)
+			    smtp_mesg_fail(state, STR(iter->host), resp,
+					"host %s said: %s (in reply to %s)",
+					   session->namaddr,
+					   translit(resp->str, "\n", " "),
+					   xfer_request[SMTP_STATE_DATA]);
+			nrcpt = -1;
+		    }
+
+		    /*
+		     * In the case of a successful address probe with target
+		     * equal to DATA, the remote server is now in the DATA
+		     * state, and therefore we must not make any further
+		     * attempt to send or receive on this connection. This
+		     * means that we cannot not reuse the general-purpose
+		     * course-correction logic below which sends RSET (and
+		     * perhaps QUIT). Instead we "jump" straight to the exit
+		     * and force an unceremonious disconnect.
+		     */
+		    else if (DEL_REQ_TRACE_ONLY(request->flags)
+			     && smtp_vrfy_tgt == SMTP_STATE_DATA) {
+			for (nrcpt = 0; nrcpt < recv_rcpt; nrcpt++) {
+			    rcpt = request->rcpt_list.info + nrcpt;
+			    if (!SMTP_RCPT_ISMARKED(rcpt)) {
+				translit(resp->str, "\n", " ");
+				SMTP_RESP_SET_DSN(resp, "2.0.0");
+				smtp_rcpt_done(state, resp, rcpt);
+			    }
+			}
+			DONT_CACHE_THIS_SESSION;
+			send_state = recv_state = SMTP_STATE_LAST;
+		    }
+		    break;
+
+		    /*
+		     * Process the end of message response. Ignore the
+		     * response when no recipient was accepted: all
+		     * recipients are dead already, and the next receiver
+		     * state is SMTP_STATE_LAST/QUIT regardless. Otherwise,
+		     * if the message transfer fails, bounce all remaining
+		     * recipients, else cross off the recipients that were
+		     * delivered.
+		     */
+		case SMTP_STATE_DOT:
+		    GETTIMEOFDAY(&request->msg_stats.deliver_done);
+		    if (smtp_mode) {
+			if (nrcpt > 0) {
+			    if (resp->code / 100 != 2) {
+				smtp_mesg_fail(state, STR(iter->host), resp,
+					"host %s said: %s (in reply to %s)",
+					       session->namaddr,
+					     translit(resp->str, "\n", " "),
+					       xfer_request[SMTP_STATE_DOT]);
+			    } else {
+				for (nrcpt = 0; nrcpt < recv_rcpt; nrcpt++) {
+				    rcpt = request->rcpt_list.info + nrcpt;
+				    if (!SMTP_RCPT_ISMARKED(rcpt)) {
+					translit(resp->str, "\n", " ");
+					smtp_rcpt_done(state, resp, rcpt);
+				    }
+				}
+			    }
+			}
+		    }
+
+		    /*
+		     * With LMTP we have one response per accepted RCPT TO
+		     * command. Stay in the SMTP_STATE_DOT state until we
+		     * have collected all responses.
+		     */
+		    else {
+			if (nrcpt > 0) {
+			    rcpt = request->rcpt_list.info
+				+ survivors[recv_done++];
+			    if (resp->code / 100 != 2) {
+				smtp_rcpt_fail(state, rcpt, STR(iter->host), resp,
+					"host %s said: %s (in reply to %s)",
+					       session->namaddr,
+					     translit(resp->str, "\n", " "),
+					       xfer_request[SMTP_STATE_DOT]);
+			    } else {
+				translit(resp->str, "\n", " ");
+				smtp_rcpt_done(state, resp, rcpt);
+			    }
+			}
+			if (msg_verbose)
+			    msg_info("%s: got %d of %d end-of-data replies",
+				     myname, recv_done, nrcpt);
+			if (recv_done < nrcpt)
+			    break;
+		    }
+
+		    /*
+		     * XXX Do not change the connection caching state here,
+		     * even if the connection caching timer expired between
+		     * generating the command and processing the reply,
+		     * otherwise the sender and receiver loops get out of
+		     * sync. The caller will call smtp_quit() if appropriate.
+		     */
+		    if (var_skip_quit_resp || THIS_SESSION_IS_CACHED
+			|| LOST_CONNECTION_INSIDE_DATA)
+			recv_state = SMTP_STATE_LAST;
+		    else
+			recv_state = SMTP_STATE_QUIT;
+		    break;
+
+		    /*
+		     * Receive the RSET response.
+		     * 
+		     * The SMTP_STATE_ABORT sender state is entered by the
+		     * sender when it has verified all recipients; or it is
+		     * entered by the receiver when all recipients are
+		     * verified or rejected, and is then left before the
+		     * bottom of the main loop.
+		     * 
+		     * XXX Do not change the connection caching state here, even
+		     * if the server rejected RSET or if the connection
+		     * caching timer expired between generating the command
+		     * and processing the reply, otherwise the sender and
+		     * receiver loops get out of sync. The caller will call
+		     * smtp_quit() if appropriate.
+		     */
+		case SMTP_STATE_ABORT:
+		    recv_state = (var_skip_quit_resp || THIS_SESSION_IS_CACHED ?
+				  SMTP_STATE_LAST : SMTP_STATE_QUIT);
+		    break;
+
+		    /*
+		     * This is the initial receiver state from smtp_rset().
+		     * It is used to find out the status of a cached session
+		     * before attempting mail delivery.
+		     */
+		case SMTP_STATE_RSET:
+		    if (resp->code / 100 != 2)
+			CANT_RSET_THIS_SESSION;
+		    recv_state = SMTP_STATE_LAST;
+		    break;
+
+		    /*
+		     * Receive, but otherwise ignore, the QUIT response.
+		     */
+		case SMTP_STATE_QUIT:
+		    recv_state = SMTP_STATE_LAST;
+		    break;
+		}
+	    }
+
+	    /*
+	     * At this point, the sender and receiver are fully synchronized.
+	     */
+
+	    /*
+	     * We know the server response to every command that was sent.
+	     * Apply a course correction if necessary: the sender wants to
+	     * send RCPT TO but MAIL FROM was rejected; the sender wants to
+	     * send DATA but all recipients were rejected; the sender wants
+	     * to deliver the message but DATA was rejected.
+	     */
+	    if ((send_state == SMTP_STATE_RCPT && mail_from_rejected)
+		|| (send_state == SMTP_STATE_DATA && nrcpt == 0)
+		|| (send_state == SMTP_STATE_DOT && nrcpt < 0)) {
+		send_state = recv_state = SMTP_STATE_ABORT;
+		send_rcpt = recv_rcpt = 0;
+		vstring_strcpy(next_command, "RSET");
+		if (THIS_SESSION_IS_EXPIRED)
+		    DONT_CACHE_THIS_SESSION;
+		next_state = THIS_SESSION_IS_CACHED ?
+		    SMTP_STATE_LAST : SMTP_STATE_QUIT;
+		/* XXX Also: record if non-delivering session. */
+		next_rcpt = 0;
+	    }
+	}
+
+	/*
+	 * Make the next sender state the current sender state.
+	 */
+	if (send_state == SMTP_STATE_LAST)
+	    continue;
+
+	/*
+	 * Special case if the server accepted the DATA command. If the
+	 * server accepted at least one recipient send the entire message.
+	 * Otherwise, just send "." as per RFC 2197.
+	 * 
+	 * XXX If there is a hard MIME error while downgrading to 7-bit mail,
+	 * disconnect ungracefully, because there is no other way to cancel a
+	 * transaction in progress.
+	 */
+	if (send_state == SMTP_STATE_DOT && nrcpt > 0) {
+
+	    smtp_stream_setup(session->stream, var_smtp_data1_tmout,
+			      var_smtp_rec_deadline);
+
+	    if ((except = vstream_setjmp(session->stream)) == 0) {
+
+		if (vstream_fseek(state->src, request->data_offset, SEEK_SET) < 0)
+		    msg_fatal("seek queue file: %m");
+
+		downgrading = SMTP_MIME_DOWNGRADE(session, request);
+
+		/*
+		 * XXX Don't downgrade just because generic_maps is turned
+		 * on.
+		 */
+#define SMTP_ANY_CHECKS (smtp_header_checks || smtp_body_checks)
+
+		if (downgrading || smtp_generic_maps || SMTP_ANY_CHECKS)
+		    session->mime_state = mime_state_alloc(downgrading ?
+							   MIME_OPT_DOWNGRADE
+						 | MIME_OPT_REPORT_NESTING :
+						      SMTP_ANY_CHECKS == 0 ?
+						     MIME_OPT_DISABLE_MIME :
+							   0,
+							   smtp_generic_maps
+						     || smtp_header_checks ?
+						       smtp_header_rewrite :
+							   smtp_header_out,
+						     (MIME_STATE_ANY_END) 0,
+							   smtp_body_checks ?
+							 smtp_body_rewrite :
+							   smtp_text_out,
+						     (MIME_STATE_ANY_END) 0,
+						   (MIME_STATE_ERR_PRINT) 0,
+							   (void *) state);
+		state->space_left = var_smtp_line_limit;
+
+		if ((smtp_cli_attr.flags & SMTP_CLI_MASK_ADD_HEADERS) != 0
+		    && smtp_out_add_headers(state) < 0)
+		    RETURN(0);
+
+		while ((rec_type = rec_get(state->src, session->scratch, 0)) > 0) {
+		    if (rec_type != REC_TYPE_NORM && rec_type != REC_TYPE_CONT)
+			break;
+		    if (smtp_out_raw_or_mime(state, rec_type,
+					     session->scratch) < 0)
+			RETURN(0);
+		    prev_type = rec_type;
+		}
+
+		if (session->mime_state) {
+
+		    /*
+		     * The cleanup server normally ends MIME content with a
+		     * normal text record. The following code is needed to
+		     * flush an internal buffer when someone submits 8-bit
+		     * mail not ending in newline via /usr/sbin/sendmail
+		     * while MIME input processing is turned off, and MIME
+		     * 8bit->7bit conversion is requested upon delivery.
+		     * 
+		     * Or some error while doing generic address mapping.
+		     */
+		    mime_errs =
+			mime_state_update(session->mime_state, rec_type, "", 0);
+		    if (mime_errs) {
+			smtp_mime_fail(state, mime_errs);
+			RETURN(0);
+		    }
+		} else if (prev_type == REC_TYPE_CONT)	/* missing newline */
+		    smtp_fputs("", 0, session->stream);
+		if (session->features & SMTP_FEATURE_PIX_DELAY_DOTCRLF) {
+		    smtp_flush(session->stream);/* hurts performance */
+		    sleep(var_smtp_pix_delay);	/* not to mention this */
+		}
+		if (vstream_ferror(state->src))
+		    msg_fatal("queue file read error");
+		if (rec_type != REC_TYPE_XTRA) {
+		    msg_warn("%s: bad record type: %d in message content",
+			     request->queue_id, rec_type);
+		    fail_status = smtp_mesg_fail(state, DSN_BY_LOCAL_MTA,
+					     SMTP_RESP_FAKE(&fake, "5.3.0"),
+					     "unreadable mail queue entry");
+		    /* Bailing out, abort stream with prejudice */
+		    (void) vstream_fpurge(session->stream, VSTREAM_PURGE_BOTH);
+		    DONT_USE_FORBIDDEN_SESSION;
+		    /* If bounce_append() succeeded, status is still 0 */
+		    if (state->status == 0)
+			(void) mark_corrupt(state->src);
+		    /* Don't override smtp_mesg_fail() here. */
+		    RETURN(fail_status);
+		}
+	    } else {
+		if (!LOST_CONNECTION_INSIDE_DATA)
+		    RETURN(smtp_stream_except(state, except,
+					      "sending message body"));
+
+		/*
+		 * We will clear the stream error flag to try and read a
+		 * premature 5XX response, so it is important to flush any
+		 * unwritten data. Otherwise, we will try to flush it again
+		 * before reading, which may incur an unnecessary delay and
+		 * will prevent the reading of any response that is not
+		 * already buffered (bundled with the DATA 354 response).
+		 * 
+		 * Not much point in sending QUIT at this point, skip right to
+		 * SMTP_STATE_LAST. The read engine above will likewise avoid
+		 * looking for a QUIT response.
+		 */
+		(void) vstream_fpurge(session->stream, VSTREAM_PURGE_WRITE);
+		next_state = SMTP_STATE_LAST;
+	    }
+	}
+
+	/*
+	 * Copy the next command to the buffer and update the sender state.
+	 */
+	if (except == 0) {
+	    smtp_chat_cmd(session, "%s", vstring_str(next_command));
+	} else {
+	    DONT_CACHE_THIS_SESSION;
+	}
+	send_state = next_state;
+	send_rcpt = next_rcpt;
+    } while (recv_state != SMTP_STATE_LAST);
+    RETURN(0);
+}
+
+/* smtp_xfer - send a batch of envelope information and the message data */
+
+int     smtp_xfer(SMTP_STATE *state)
+{
+    DELIVER_REQUEST *request = state->request;
+    SMTP_SESSION *session = state->session;
+    SMTP_RESP fake;
+    int     send_state;
+    int     recv_state;
+    int     send_name_addr;
+    int     result;
+
+    /*
+     * Sanity check. Recipients should be unmarked at this point.
+     */
+    if (SMTP_RCPT_LEFT(state) <= 0)
+	msg_panic("smtp_xfer: bad recipient count: %d",
+		  SMTP_RCPT_LEFT(state));
+    if (SMTP_RCPT_ISMARKED(request->rcpt_list.info))
+	msg_panic("smtp_xfer: bad recipient status: %d",
+		  request->rcpt_list.info->u.status);
+
+    /*
+     * See if we should even try to send this message at all. This code sits
+     * here rather than in the EHLO processing code, because of SMTP
+     * connection caching.
+     */
+    if (session->size_limit > 0 && session->size_limit < request->data_size) {
+	smtp_mesg_fail(state, DSN_BY_LOCAL_MTA,
+		       SMTP_RESP_FAKE(&fake, "5.3.4"),
+		    "message size %lu exceeds size limit %.0f of server %s",
+		       request->data_size, (double) session->size_limit,
+		       session->namaddr);
+	/* Redundant. We abort this delivery attempt. */
+	state->misc_flags |= SMTP_MISC_FLAG_COMPLETE_SESSION;
+	return (0);
+    }
+
+    /*
+     * Use XFORWARD to forward the origin of this email message across an
+     * SMTP-based content filter. Send client attribute information only if
+     * it exists (i.e. remote submission). Local submissions have no client
+     * attributes; the mail will appear to originate from the content filter
+     * which is acceptable.
+     */
+    send_name_addr =
+	var_smtp_send_xforward
+	&& (((session->features & SMTP_FEATURE_XFORWARD_NAME)
+	     && CAN_FORWARD_CLIENT_NAME(request->client_name))
+	    || ((session->features & SMTP_FEATURE_XFORWARD_ADDR)
+		&& CAN_FORWARD_CLIENT_ADDR(request->client_addr))
+	    || ((session->features & SMTP_FEATURE_XFORWARD_PORT)
+		&& CAN_FORWARD_CLIENT_PORT(request->client_port)));
+    session->send_proto_helo =
+	var_smtp_send_xforward
+	&& (((session->features & SMTP_FEATURE_XFORWARD_PROTO)
+	     && CAN_FORWARD_PROTO_NAME(request->client_proto))
+	    || ((session->features & SMTP_FEATURE_XFORWARD_HELO)
+		&& CAN_FORWARD_HELO_NAME(request->client_helo))
+	    || ((session->features & SMTP_FEATURE_XFORWARD_IDENT)
+		&& CAN_FORWARD_IDENT_NAME(request->log_ident))
+	    || ((session->features & SMTP_FEATURE_XFORWARD_DOMAIN)
+		&& CAN_FORWARD_RWR_CONTEXT(request->rewrite_context)));
+    if (send_name_addr)
+	recv_state = send_state = SMTP_STATE_XFORWARD_NAME_ADDR;
+    else if (session->send_proto_helo)
+	recv_state = send_state = SMTP_STATE_XFORWARD_PROTO_HELO;
+    else
+	recv_state = send_state = SMTP_STATE_MAIL;
+
+    /*
+     * Remember this session's "normal completion", even if the server 4xx-ed
+     * some or all recipients. Connection or handshake errors with a later MX
+     * host should not cause this destination be marked as unreachable.
+     */
+    result = smtp_loop(state, send_state, recv_state);
+
+    if (result == 0
+    /* Just in case */
+	&& vstream_ferror(session->stream) == 0
+	&& vstream_feof(session->stream) == 0)
+	state->misc_flags |= SMTP_MISC_FLAG_COMPLETE_SESSION;
+
+    return (result);
+}
+
+/* smtp_rset - send a lone RSET command */
+
+int     smtp_rset(SMTP_STATE *state)
+{
+
+    /*
+     * This works because SMTP_STATE_RSET is a dedicated sender/recipient
+     * entry state, with SMTP_STATE_LAST as next sender/recipient state.
+     */
+    return (smtp_loop(state, SMTP_STATE_RSET, SMTP_STATE_RSET));
+}
+
+/* smtp_quit - send a lone QUIT command */
+
+int     smtp_quit(SMTP_STATE *state)
+{
+
+    /*
+     * This works because SMTP_STATE_QUIT is the last state with a sender
+     * action, with SMTP_STATE_LAST as the next sender/recipient state.
+     */
+    return (smtp_loop(state, SMTP_STATE_QUIT, var_skip_quit_resp ?
+		      SMTP_STATE_LAST : SMTP_STATE_QUIT));
+}
diff --git a/src/smtp/smtp_rcpt.c b/src/smtp/smtp_rcpt.c
new file mode 100644
index 0000000..6608ea8
--- /dev/null
+++ b/src/smtp/smtp_rcpt.c
@@ -0,0 +1,226 @@
+/*++
+/* NAME
+/*	smtp_rcpt 3
+/* SUMMARY
+/*	application-specific recipient list operations
+/* SYNOPSIS
+/*	#include <smtp.h>
+/*
+/*	SMTP_RCPT_INIT(state)
+/*	SMTP_STATE *state;
+/*
+/*	SMTP_RCPT_DROP(state, rcpt)
+/*	SMTP_STATE *state;
+/*	RECIPIENT *rcpt;
+/*
+/*	SMTP_RCPT_KEEP(state, rcpt)
+/*	SMTP_STATE *state;
+/*	RECIPIENT *rcpt;
+/*
+/*	SMTP_RCPT_ISMARKED(rcpt)
+/*	RECIPIENT *rcpt;
+/*
+/*	void	smtp_rcpt_cleanup(SMTP_STATE *state)
+/*	SMTP_STATE *state;
+/*
+/*	int	SMTP_RCPT_LEFT(state)
+/*	SMTP_STATE *state;
+/*
+/*	int	SMTP_RCPT_MARK_COUNT(state)
+/*	SMTP_STATE *state;
+/*
+/*	void	smtp_rcpt_done(state, resp, rcpt)
+/*	SMTP_STATE *state;
+/*	SMTP_RESP *resp;
+/*	RECIPIENT *rcpt;
+/* DESCRIPTION
+/*	This module implements application-specific mark and sweep
+/*	operations on recipient lists. Operation is as follows:
+/* .IP \(bu
+/*	In the course of a delivery attempt each recipient is
+/*	marked either as DROP (remove from recipient list) or KEEP
+/*	(deliver to alternate mail server).
+/* .IP \(bu
+/*	After a delivery attempt any recipients marked DROP are deleted
+/*	from the request, and the left-over recipients are unmarked.
+/* .PP
+/*	The mark/sweep algorithm is implemented in a redundant manner,
+/*	and ensures that all recipients are explicitly accounted for.
+/*
+/*	Operations with upper case names are implemented by macros
+/*	whose arguments may be evaluated more than once.
+/*
+/*	SMTP_RCPT_INIT() initializes application-specific recipient
+/*	information and must be called before the first delivery attempt.
+/*
+/*	SMTP_RCPT_DROP() marks the specified recipient as DROP (remove
+/*	from recipient list). It is an error to mark an already marked
+/*	recipient.
+/*
+/*	SMTP_RCPT_KEEP() marks the specified recipient as KEEP (deliver
+/*	to alternate mail server). It is an error to mark an already
+/*	marked recipient.
+/*
+/*	SMTP_RCPT_ISMARKED() returns non-zero when the specified
+/*	recipient is marked.
+/*
+/*	SMTP_RCPT_LEFT() returns the number of left_over recipients
+/*	(the total number of marked and non-marked recipients).
+/*
+/*	SMTP_RCPT_MARK_COUNT() returns the number of left_over
+/*	recipients that are marked.
+/*
+/*	smtp_rcpt_cleanup() cleans up the in-memory recipient list.
+/*	It removes the recipients marked DROP from the left-over
+/*	recipients, unmarks the left-over recipients, and enforces
+/*	the requirement that all recipients are marked upon entry.
+/*
+/*	smtp_rcpt_done() logs that a recipient is completed and upon
+/*	success it marks the recipient as done in the queue file.
+/*	Finally, it marks the in-memory recipient as DROP.
+/*
+/*	Note: smtp_rcpt_done() may change the order of the recipient
+/*	list.
+/* DIAGNOSTICS
+/*	Panic: interface violation.
+/*
+/*	When a recipient can't be logged as completed, the recipient is
+/*	logged as deferred instead.
+/* BUGS
+/*	The single recipient list abstraction dates from the time
+/*	that the SMTP client would give up after one SMTP session,
+/*	so that each recipient was either bounced, delivered or
+/*	deferred. Implicitly, all recipients were marked as DROP.
+/*
+/*	This abstraction is less convenient when an SMTP client
+/*	must be able to deliver left-over recipients to a backup
+/*	host. It might be more natural to have an input list with
+/*	recipients to deliver, and an output list with left-over
+/*	recipients.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System  library. */
+
+#include <sys_defs.h>
+#include <stdlib.h>			/* smtp_rcpt_cleanup  */
+#include <string.h>
+
+/* Utility  library. */
+
+#include <msg.h>
+#include <stringops.h>
+#include <mymalloc.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <deliver_request.h>		/* smtp_rcpt_done */
+#include <deliver_completed.h>		/* smtp_rcpt_done */
+#include <sent.h>			/* smtp_rcpt_done */
+#include <dsn_mask.h>			/* smtp_rcpt_done */
+
+/* Application-specific. */
+
+#include <smtp.h>
+
+/* smtp_rcpt_done - mark recipient as done or else */
+
+void    smtp_rcpt_done(SMTP_STATE *state, SMTP_RESP *resp, RECIPIENT *rcpt)
+{
+    DELIVER_REQUEST *request = state->request;
+    SMTP_SESSION *session = state->session;
+    SMTP_ITERATOR *iter = state->iterator;
+    DSN_BUF *why = state->why;
+    const char *dsn_action = "relayed";
+    int     status;
+
+    /*
+     * Assume this was intermediate delivery when the server announced DSN
+     * support, and don't send a DSN "SUCCESS" notification.
+     */
+    if (session->features & SMTP_FEATURE_DSN)
+	rcpt->dsn_notify &= ~DSN_NOTIFY_SUCCESS;
+
+    /*
+     * Assume this was final delivery when the LMTP server announced no DSN
+     * support. In backwards compatibility mode, send a "relayed" instead of
+     * a "delivered" DSN "SUCCESS" notification. Do not attempt to "simplify"
+     * the expression. The redundancy is for clarity. It is trivially
+     * eliminated by the compiler. There is no need to sacrifice clarity for
+     * the sake of "performance".
+     */
+    if ((session->features & SMTP_FEATURE_DSN) == 0
+	&& !smtp_mode
+	&& (smtp_cli_attr.flags & SMTP_CLI_FLAG_FINAL_DELIVERY) != 0)
+	dsn_action = "delivered";
+
+    /*
+     * Report success and delete the recipient from the delivery request.
+     * Defer if the success can't be reported.
+     * 
+     * Note: the DSN action is ignored in case of address probes.
+     */
+    dsb_update(why, resp->dsn, dsn_action, DSB_MTYPE_DNS, STR(iter->host),
+	       DSB_DTYPE_SMTP, resp->str, "%s", resp->str);
+
+    status = sent(DEL_REQ_TRACE_FLAGS(request->flags),
+		  request->queue_id, &request->msg_stats, rcpt,
+		  session->namaddrport, DSN_FROM_DSN_BUF(why));
+    if (status == 0)
+	if (request->flags & DEL_REQ_FLAG_SUCCESS)
+	    deliver_completed(state->src, rcpt->offset);
+    SMTP_RCPT_DROP(state, rcpt);
+    state->status |= status;
+}
+
+/* smtp_rcpt_cleanup_callback - qsort callback */
+
+static int smtp_rcpt_cleanup_callback(const void *a, const void *b)
+{
+    return (((RECIPIENT *) a)->u.status - ((RECIPIENT *) b)->u.status);
+}
+
+/* smtp_rcpt_cleanup - purge completed recipients from request */
+
+void    smtp_rcpt_cleanup(SMTP_STATE *state)
+{
+    RECIPIENT_LIST *rcpt_list = &state->request->rcpt_list;
+    RECIPIENT *rcpt;
+
+    /*
+     * Sanity checks.
+     */
+    if (state->rcpt_drop + state->rcpt_keep != state->rcpt_left)
+	msg_panic("smtp_rcpt_cleanup: recipient count mismatch: %d+%d!=%d",
+		  state->rcpt_drop, state->rcpt_keep, state->rcpt_left);
+
+    /*
+     * Recipients marked KEEP sort before recipients marked DROP. Skip the
+     * sorting in the common case that all recipients are marked the same.
+     */
+    if (state->rcpt_drop > 0 && state->rcpt_keep > 0)
+	qsort((void *) rcpt_list->info, state->rcpt_left,
+	      sizeof(rcpt_list->info[0]), smtp_rcpt_cleanup_callback);
+
+    /*
+     * Truncate the recipient list and unmark the left-over recipients.
+     */
+    state->rcpt_left = state->rcpt_keep;
+    for (rcpt = rcpt_list->info; rcpt < rcpt_list->info + state->rcpt_left; rcpt++)
+	rcpt->u.status = 0;
+    state->rcpt_drop = state->rcpt_keep = 0;
+}
diff --git a/src/smtp/smtp_reuse.c b/src/smtp/smtp_reuse.c
new file mode 100644
index 0000000..f93ba29
--- /dev/null
+++ b/src/smtp/smtp_reuse.c
@@ -0,0 +1,269 @@
+/*++
+/* NAME
+/*	smtp_reuse 3
+/* SUMMARY
+/*	SMTP session cache glue
+/* SYNOPSIS
+/*	#include <smtp.h>
+/*	#include <smtp_reuse.h>
+/*
+/*	void	smtp_save_session(state, name_key_flags, endp_key_flags)
+/*	SMTP_STATE *state;
+/*	int	name_key_flags;
+/*	int	endp_key_flags;
+/*
+/*	SMTP_SESSION *smtp_reuse_nexthop(state, name_key_flags)
+/*	SMTP_STATE *state;
+/*	int	name_key_flags;
+/*
+/*	SMTP_SESSION *smtp_reuse_addr(state, endp_key_flags)
+/*	SMTP_STATE *state;
+/*	int	endp_key_flags;
+/* DESCRIPTION
+/*	This module implements the SMTP client specific interface to
+/*	the generic session cache infrastructure.
+/*
+/*	The caller needs to include additional state in _key_flags
+/*	to avoid false sharing of SASL-authenticated or TLS-authenticated
+/*	sessions.
+/*
+/*	smtp_save_session() stores the current session under the
+/*	delivery request next-hop logical destination (if applicable)
+/*	and under the remote server address. The SMTP_SESSION object
+/*	is destroyed.
+/*
+/*	smtp_reuse_nexthop() looks up a cached session by its
+/*	delivery request next-hop destination, and verifies that
+/*	the session is still alive. The restored session information
+/*	includes the "best MX" bit and overrides the iterator dest,
+/*	host and addr fields. The result is null in case of failure.
+/*
+/*	smtp_reuse_addr() looks up a cached session by its server
+/*	address, and verifies that the session is still alive.
+/*	The restored session information does not include the "best
+/*	MX" bit, and does not override the iterator dest, host and
+/*	addr fields. The result is null in case of failure.
+/*
+/*	Arguments:
+/* .IP state
+/*	SMTP client state, including the current session, the original
+/*	next-hop domain, etc.
+/* .IP name_key_flags
+/*	Explicit declaration of context that should be used to look
+/*	up a cached connection by its logical destination.
+/*	See smtp_key(3) for details.
+/* .IP endp_key_flags
+/*	Explicit declaration of context that should be used to look
+/*	up a cached connection by its server address.
+/*	See smtp_key(3) for details.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstream.h>
+#include <vstring.h>
+#include <htable.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <scache.h>
+#include <mail_params.h>
+
+/* Application-specific. */
+
+#include <smtp.h>
+#include <smtp_reuse.h>
+
+ /*
+  * Key field delimiter, and place holder field value for
+  * unavailable/inapplicable information.
+  */
+#define SMTP_REUSE_KEY_DELIM_NA	"\n*"
+
+/* smtp_save_session - save session under next-hop name and server address */
+
+void    smtp_save_session(SMTP_STATE *state, int name_key_flags,
+			          int endp_key_flags)
+{
+    SMTP_SESSION *session = state->session;
+    int     fd;
+
+    /*
+     * Encode the delivery request next-hop destination, if applicable. Reuse
+     * storage that is also used for cache lookup queries.
+     * 
+     * HAVE_SCACHE_REQUEST_NEXTHOP() controls whether or not to reuse or cache a
+     * connection by its delivery request next-hop destination. The idea is
+     * 1) to allow a reuse request to skip over bad hosts, and 2) to avoid
+     * caching a less-preferred connection when a more-preferred connection
+     * was possible.
+     */
+    if (HAVE_SCACHE_REQUEST_NEXTHOP(state))
+	smtp_key_prefix(state->dest_label, SMTP_REUSE_KEY_DELIM_NA,
+			state->iterator, name_key_flags);
+
+    /*
+     * Encode the physical endpoint name. Reuse storage that is also used for
+     * cache lookup queries.
+     */
+    smtp_key_prefix(state->endp_label, SMTP_REUSE_KEY_DELIM_NA,
+		    state->iterator, endp_key_flags);
+
+    /*
+     * Passivate the SMTP_SESSION object, destroying the object in the
+     * process. Reuse storage that is also used for cache lookup results.
+     */
+    fd = smtp_session_passivate(session, state->dest_prop, state->endp_prop);
+    state->session = 0;
+
+    /*
+     * Save the session under the delivery request next-hop name, if
+     * applicable.
+     * 
+     * XXX The logical to physical binding can be kept for as long as the DNS
+     * allows us to (but that could result in the caching of lots of unused
+     * bindings). The session should be idle for no more than 30 seconds or
+     * so.
+     */
+    if (HAVE_SCACHE_REQUEST_NEXTHOP(state))
+	scache_save_dest(smtp_scache, var_smtp_cache_conn,
+			 STR(state->dest_label), STR(state->dest_prop),
+			 STR(state->endp_label));
+
+    /*
+     * Save every good session under its physical endpoint address.
+     */
+    scache_save_endp(smtp_scache, var_smtp_cache_conn, STR(state->endp_label),
+		     STR(state->endp_prop), fd);
+}
+
+/* smtp_reuse_common - common session reuse code */
+
+static SMTP_SESSION *smtp_reuse_common(SMTP_STATE *state, int fd,
+				               const char *label)
+{
+    const char *myname = "smtp_reuse_common";
+    SMTP_ITERATOR *iter = state->iterator;
+    SMTP_SESSION *session;
+
+    /*
+     * Re-activate the SMTP_SESSION object.
+     */
+    session = smtp_session_activate(fd, state->iterator, state->dest_prop,
+				    state->endp_prop);
+    if (session == 0) {
+	msg_warn("%s: bad cached session attribute for %s", myname, label);
+	(void) close(fd);
+	return (0);
+    }
+    state->session = session;
+    session->state = state;
+
+    /*
+     * Send an RSET probe to verify that the session is still good.
+     */
+    if (smtp_rset(state) < 0
+	|| (session->features & SMTP_FEATURE_RSET_REJECTED) != 0) {
+	smtp_session_free(session);
+	return (state->session = 0);
+    }
+
+    /*
+     * Avoid poor performance when TCP MSS > VSTREAM_BUFSIZE.
+     */
+    vstream_tweak_sock(session->stream);
+
+    /*
+     * Update the list of used cached addresses.
+     */
+    htable_enter(state->cache_used, STR(iter->addr), (void *) 0);
+
+    return (session);
+}
+
+/* smtp_reuse_nexthop - reuse session cached under nexthop name */
+
+SMTP_SESSION *smtp_reuse_nexthop(SMTP_STATE *state, int name_key_flags)
+{
+    SMTP_SESSION *session;
+    int     fd;
+
+    /*
+     * Look up the session by its logical name.
+     */
+    smtp_key_prefix(state->dest_label, SMTP_REUSE_KEY_DELIM_NA,
+		    state->iterator, name_key_flags);
+    if ((fd = scache_find_dest(smtp_scache, STR(state->dest_label),
+			       state->dest_prop, state->endp_prop)) < 0)
+	return (0);
+
+    /*
+     * Re-activate the SMTP_SESSION object, and verify that the session is
+     * still good.
+     */
+    session = smtp_reuse_common(state, fd, STR(state->dest_label));
+    return (session);
+}
+
+/* smtp_reuse_addr - reuse session cached under numerical address */
+
+SMTP_SESSION *smtp_reuse_addr(SMTP_STATE *state, int endp_key_flags)
+{
+    SMTP_SESSION *session;
+    int     fd;
+
+    /*
+     * Address-based reuse is safe for security levels that require TLS
+     * certificate checks, as long as the current nexhop is included in the
+     * cache lookup key (COND_TLS_SMTP_KEY_FLAG_CUR_NEXTHOP). This is
+     * sufficient to prevent the reuse of a TLS-authenticated connection to
+     * the same MX hostname, IP address, and port, but for a different
+     * current nexthop destination with a different TLS policy.
+     */
+
+    /*
+     * Look up the session by its IP address. This means that we have no
+     * destination-to-address binding properties.
+     */
+    smtp_key_prefix(state->endp_label, SMTP_REUSE_KEY_DELIM_NA,
+		    state->iterator, endp_key_flags);
+    if ((fd = scache_find_endp(smtp_scache, STR(state->endp_label),
+			       state->endp_prop)) < 0)
+	return (0);
+    VSTRING_RESET(state->dest_prop);
+    VSTRING_TERMINATE(state->dest_prop);
+
+    /*
+     * Re-activate the SMTP_SESSION object, and verify that the session is
+     * still good.
+     */
+    session = smtp_reuse_common(state, fd, STR(state->endp_label));
+
+    return (session);
+}
diff --git a/src/smtp/smtp_reuse.h b/src/smtp/smtp_reuse.h
new file mode 100644
index 0000000..8c6cb48
--- /dev/null
+++ b/src/smtp/smtp_reuse.h
@@ -0,0 +1,27 @@
+/*++
+/* NAME
+/*	smtp_reuse 3h
+/* SUMMARY
+/*	SMTP session cache glue
+/* SYNOPSIS
+/*	#include <smtp_reuse.h>
+/* DESCRIPTION
+/* .nf
+
+ /*
+  * Internal interfaces.
+  */
+extern void smtp_save_session(SMTP_STATE *, int, int);
+extern SMTP_SESSION *smtp_reuse_nexthop(SMTP_STATE *, int);
+extern SMTP_SESSION *smtp_reuse_addr(SMTP_STATE *, int);
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
diff --git a/src/smtp/smtp_sasl.h b/src/smtp/smtp_sasl.h
new file mode 100644
index 0000000..756d13d
--- /dev/null
+++ b/src/smtp/smtp_sasl.h
@@ -0,0 +1,43 @@
+/*++
+/* NAME
+/*	smtp_sasl 3h
+/* SUMMARY
+/*	Postfix SASL interface for SMTP client
+/* SYNOPSIS
+/*	#include "smtp_sasl.h"
+/* DESCRIPTION
+/* .nf
+
+ /*
+ * SASL protocol functions
+ */
+extern void smtp_sasl_initialize(void);
+extern void smtp_sasl_connect(SMTP_SESSION *);
+extern int smtp_sasl_passwd_lookup(SMTP_SESSION *);
+extern void smtp_sasl_start(SMTP_SESSION *, const char *, const char *);
+extern int smtp_sasl_authenticate(SMTP_SESSION *, DSN_BUF *);
+extern void smtp_sasl_cleanup(SMTP_SESSION *);
+
+extern void smtp_sasl_helo_auth(SMTP_SESSION *, const char *);
+extern int smtp_sasl_helo_login(SMTP_STATE *);
+
+extern void smtp_sasl_passivate(SMTP_SESSION *, VSTRING *);
+extern int smtp_sasl_activate(SMTP_SESSION *, char *);
+extern STRING_LIST *smtp_sasl_mechs;
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Initial implementation by:
+/*	Till Franke
+/*	SuSE Rhein/Main AG
+/*	65760 Eschborn, Germany
+/*
+/*	Adopted by:
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
diff --git a/src/smtp/smtp_sasl_auth_cache.c b/src/smtp/smtp_sasl_auth_cache.c
new file mode 100644
index 0000000..f3104ca
--- /dev/null
+++ b/src/smtp/smtp_sasl_auth_cache.c
@@ -0,0 +1,272 @@
+/*++
+/* NAME
+/*	smtp_sasl_auth_cache 3
+/* SUMMARY
+/*	Postfix SASL authentication reply cache
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*	#include "smtp_sasl_auth_cache.h"
+/*
+/*	SMTP_SASL_AUTH_CACHE *smtp_sasl_auth_cache_init(map, ttl)
+/*	const char *map
+/*	int	ttl;
+/*
+/*	void	smtp_sasl_auth_cache_store(auth_cache, session, resp)
+/*	SMTP_SASL_AUTH_CACHE *auth_cache;
+/*	const SMTP_SESSION *session;
+/*	const SMTP_RESP *resp;
+/*
+/*	int	smtp_sasl_auth_cache_find(auth_cache, session)
+/*	SMTP_SASL_AUTH_CACHE *auth_cache;
+/*	const SMTP_SESSION *session;
+/*
+/*	char	*smtp_sasl_auth_cache_dsn(auth_cache)
+/*	SMTP_SASL_AUTH_CACHE *auth_cache;
+/*
+/*	char	*smtp_sasl_auth_cache_text(auth_cache)
+/*	SMTP_SASL_AUTH_CACHE *auth_cache;
+/* DESCRIPTION
+/*	This module maintains a cache of SASL authentication server replies.
+/*	This can be used to avoid repeated login failure errors.
+/*
+/*	smtp_sasl_auth_cache_init() opens or creates the named cache.
+/*
+/*	smtp_sasl_auth_cache_store() stores information about a
+/*	SASL login attempt together with the server status and
+/*	complete response.
+/*
+/*	smtp_sasl_auth_cache_find() returns non-zero when a cache
+/*	entry exists for the given host, username and password.
+/*
+/*	smtp_sasl_auth_cache_dsn() and smtp_sasl_auth_cache_text()
+/*	return the status and complete server response as found
+/*	with smtp_sasl_auth_cache_find().
+/*
+/*	Arguments:
+/* .IP map
+/*	Lookup table name. The name must be singular and must start
+/*	with "proxy:".
+/* .IP ttl
+/*	The time after which a cache entry is considered expired.
+/* .IP session
+/*	Session context.
+/* .IP resp
+/*	Remote SMTP server response, to be stored into the cache.
+/* DIAGNOSTICS
+/*	All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Original author:
+/*	Keean Schupke
+/*	Fry-IT Ltd.
+/*
+/*	Updated by:
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+
+ /*
+  * Utility library
+  */
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+#include <base64_code.h>
+#include <dict.h>
+
+ /*
+  * Global library
+  */
+#include <dsn_util.h>
+#include <dict_proxy.h>
+
+ /*
+  * Application-specific
+  */
+#include "smtp.h"
+#include "smtp_sasl_auth_cache.h"
+
+ /*
+  * XXX This feature stores passwords, so we must mask them with a strong
+  * cryptographic hash. This requires OpenSSL support.
+  * 
+  * XXX It would be even better if the stored hash were salted.
+  */
+#ifdef HAVE_SASL_AUTH_CACHE
+
+/* smtp_sasl_auth_cache_init - per-process initialization (pre jail) */
+
+SMTP_SASL_AUTH_CACHE *smtp_sasl_auth_cache_init(const char *map, int ttl)
+{
+    const char *myname = "smtp_sasl_auth_cache_init";
+    SMTP_SASL_AUTH_CACHE *auth_cache;
+
+    /*
+     * Sanity checks.
+     */
+#define HAS_MULTIPLE_VALUES(s) ((s)[strcspn((s),  CHARS_COMMA_SP)] != 0)
+
+    if (*map == 0)
+	msg_panic("%s: empty SASL authentication cache name", myname);
+    if (ttl < 0)
+	msg_panic("%s: bad SASL authentication cache ttl: %d", myname, ttl);
+    if (HAS_MULTIPLE_VALUES(map))
+	msg_fatal("SASL authentication cache name \"%s\" "
+		  "contains multiple values", map);
+
+    /*
+     * XXX To avoid multiple writers the map needs to be maintained by the
+     * proxywrite service. We would like to have a DICT_FLAG_REQ_PROXY flag
+     * so that the library can enforce this, but that requires moving the
+     * dict_proxy module one level down in the build dependency hierarchy.
+     */
+#define CACHE_DICT_OPEN_FLAGS \
+	(DICT_FLAG_DUP_REPLACE | DICT_FLAG_SYNC_UPDATE | DICT_FLAG_UTF8_REQUEST)
+#define PROXY_COLON	DICT_TYPE_PROXY ":"
+#define PROXY_COLON_LEN	(sizeof(PROXY_COLON) - 1)
+
+    if (strncmp(map, PROXY_COLON, PROXY_COLON_LEN) != 0)
+	msg_fatal("SASL authentication cache name \"%s\" must start with \""
+		  PROXY_COLON, map);
+
+    auth_cache = (SMTP_SASL_AUTH_CACHE *) mymalloc(sizeof(*auth_cache));
+    auth_cache->dict = dict_open(map, O_CREAT | O_RDWR, CACHE_DICT_OPEN_FLAGS);
+    auth_cache->ttl = ttl;
+    auth_cache->dsn = mystrdup("");
+    auth_cache->text = mystrdup("");
+    return (auth_cache);
+}
+
+ /*
+  * Each cache lookup key contains a server host name and user name. Each
+  * cache value contains a time stamp, a hashed password, and the server
+  * response. With this organization, we don't have to worry about cache
+  * pollution, because we can detect if a cache entry has expired, or if the
+  * password has changed.
+  */
+
+/* smtp_sasl_auth_cache_make_key - format auth failure cache lookup key */
+
+static char *smtp_sasl_auth_cache_make_key(const char *host, const char *user)
+{
+    VSTRING *buf = vstring_alloc(100);
+
+    vstring_sprintf(buf, "%s;%s", host, user);
+    return (vstring_export(buf));
+}
+
+/* smtp_sasl_auth_cache_make_pass - hash the auth failure cache password */
+
+static char *smtp_sasl_auth_cache_make_pass(const char *password)
+{
+    VSTRING *buf = vstring_alloc(2 * SHA_DIGEST_LENGTH);
+
+    base64_encode(buf, (const char *) SHA1((const unsigned char *) password,
+					   strlen(password), 0),
+		  SHA_DIGEST_LENGTH);
+    return (vstring_export(buf));
+}
+
+/* smtp_sasl_auth_cache_make_value - format auth failure cache value */
+
+static char *smtp_sasl_auth_cache_make_value(const char *password,
+					             const char *dsn,
+					             const char *rep_str)
+{
+    VSTRING *val_buf = vstring_alloc(100);
+    char   *pwd_hash;
+    unsigned long now = (unsigned long) time((time_t *) 0);
+
+    pwd_hash = smtp_sasl_auth_cache_make_pass(password);
+    vstring_sprintf(val_buf, "%lu;%s;%s;%s", now, pwd_hash, dsn, rep_str);
+    myfree(pwd_hash);
+    return (vstring_export(val_buf));
+}
+
+/* smtp_sasl_auth_cache_valid_value - validate auth failure cache value */
+
+static int smtp_sasl_auth_cache_valid_value(SMTP_SASL_AUTH_CACHE *auth_cache,
+					            const char *entry,
+					            const char *password)
+{
+    ssize_t len = strlen(entry);
+    char   *cache_hash = mymalloc(len);
+    char   *curr_hash;
+    unsigned long now = (unsigned long) time((time_t *) 0);
+    unsigned long time_stamp;
+    int     valid;
+
+    auth_cache->dsn = myrealloc(auth_cache->dsn, len);
+    auth_cache->text = myrealloc(auth_cache->text, len);
+
+    if (sscanf(entry, "%lu;%[^;];%[^;];%[^\n]", &time_stamp, cache_hash,
+	       auth_cache->dsn, auth_cache->text) != 4
+	|| !dsn_valid(auth_cache->dsn)) {
+	msg_warn("bad smtp_sasl_auth_cache entry: %.100s", entry);
+	valid = 0;
+    } else if (time_stamp + auth_cache->ttl < now) {
+	valid = 0;
+    } else {
+	curr_hash = smtp_sasl_auth_cache_make_pass(password);
+	valid = (strcmp(cache_hash, curr_hash) == 0);
+	myfree(curr_hash);
+    }
+    myfree(cache_hash);
+    return (valid);
+}
+
+/* smtp_sasl_auth_cache_find - search auth failure cache */
+
+int     smtp_sasl_auth_cache_find(SMTP_SASL_AUTH_CACHE *auth_cache,
+				          const SMTP_SESSION *session)
+{
+    SMTP_ITERATOR *iter = session->iterator;
+    char   *key;
+    const char *entry;
+    int     valid = 0;
+
+    key = smtp_sasl_auth_cache_make_key(STR(iter->host), session->sasl_username);
+    if ((entry = dict_get(auth_cache->dict, key)) != 0)
+	if ((valid = smtp_sasl_auth_cache_valid_value(auth_cache, entry,
+						session->sasl_passwd)) == 0)
+	    /* Remove expired, password changed, or malformed cache entry. */
+	    if (dict_del(auth_cache->dict, key) != 0)
+		msg_warn("SASL auth failure map %s: entry not deleted: %s",
+			 auth_cache->dict->name, key);
+    if (auth_cache->dict->error)
+	msg_warn("SASL auth failure map %s: lookup failed for %s",
+		 auth_cache->dict->name, key);
+    myfree(key);
+    return (valid);
+}
+
+/* smtp_sasl_auth_cache_store - update auth failure cache */
+
+void    smtp_sasl_auth_cache_store(SMTP_SASL_AUTH_CACHE *auth_cache,
+				           const SMTP_SESSION *session,
+				           const SMTP_RESP *resp)
+{
+    SMTP_ITERATOR *iter = session->iterator;
+    char   *key;
+    char   *value;
+
+    key = smtp_sasl_auth_cache_make_key(STR(iter->host), session->sasl_username);
+    value = smtp_sasl_auth_cache_make_value(session->sasl_passwd,
+					    resp->dsn, resp->str);
+    dict_put(auth_cache->dict, key, value);
+
+    myfree(value);
+    myfree(key);
+}
+
+#endif
diff --git a/src/smtp/smtp_sasl_auth_cache.h b/src/smtp/smtp_sasl_auth_cache.h
new file mode 100644
index 0000000..cbbdb0d
--- /dev/null
+++ b/src/smtp/smtp_sasl_auth_cache.h
@@ -0,0 +1,62 @@
+#ifndef _SMTP_SASL_AUTH_CACHE_H_INCLUDED_
+#define _SMTP_SASL_AUTH_CACHE_H_INCLUDED_
+
+/*++
+/* NAME
+/*	smtp_sasl_auth_cache 3h
+/* SUMMARY
+/*	Postfix SASL authentication failure cache
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*	#include "smtp_sasl_auth_cache.h"
+/* DESCRIPTION
+/* .nf
+
+ /*
+  * Utility library.
+  */
+#include <dict.h>
+
+ /*
+  * This code stores hashed passwords which requires OpenSSL.
+  */
+#if defined(USE_TLS) && defined(USE_SASL_AUTH)
+#define HAVE_SASL_AUTH_CACHE
+
+ /*
+  * External interface.
+  */
+typedef struct {
+    DICT   *dict;
+    int     ttl;
+    char   *dsn;
+    char   *text;
+} SMTP_SASL_AUTH_CACHE;
+
+extern SMTP_SASL_AUTH_CACHE *smtp_sasl_auth_cache_init(const char *, int);
+extern void smtp_sasl_auth_cache_store(SMTP_SASL_AUTH_CACHE *, const SMTP_SESSION *, const SMTP_RESP *);
+extern int smtp_sasl_auth_cache_find(SMTP_SASL_AUTH_CACHE *, const SMTP_SESSION *);
+
+#define smtp_sasl_auth_cache_dsn(cp)	((cp)->dsn)
+#define smtp_sasl_auth_cache_text(cp)	((cp)->text)
+
+#endif
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Initial implementation by:
+/*	Till Franke
+/*	SuSE Rhein/Main AG
+/*	65760 Eschborn, Germany
+/*
+/*	Adopted by:
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+#endif
diff --git a/src/smtp/smtp_sasl_glue.c b/src/smtp/smtp_sasl_glue.c
new file mode 100644
index 0000000..ef8e8c4
--- /dev/null
+++ b/src/smtp/smtp_sasl_glue.c
@@ -0,0 +1,512 @@
+/*++
+/* NAME
+/*	smtp_sasl_glue 3
+/* SUMMARY
+/*	Postfix SASL interface for SMTP client
+/* SYNOPSIS
+/*	#include smtp_sasl.h
+/*
+/*	void	smtp_sasl_initialize()
+/*
+/*	void	smtp_sasl_connect(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_sasl_start(session, sasl_opts_name, sasl_opts_val)
+/*	SMTP_SESSION *session;
+/*
+/*	int     smtp_sasl_passwd_lookup(session)
+/*	SMTP_SESSION *session;
+/*
+/*	int	smtp_sasl_authenticate(session, why)
+/*	SMTP_SESSION *session;
+/*	DSN_BUF *why;
+/*
+/*	void	smtp_sasl_cleanup(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_sasl_passivate(session, buf)
+/*	SMTP_SESSION *session;
+/*	VSTRING	*buf;
+/*
+/*	int	smtp_sasl_activate(session, buf)
+/*	SMTP_SESSION *session;
+/*	char	*buf;
+/* DESCRIPTION
+/*	smtp_sasl_initialize() initializes the SASL library. This
+/*	routine must be called once at process startup, before any
+/*	chroot operations.
+/*
+/*	smtp_sasl_connect() performs per-session initialization. This
+/*	routine must be called once at the start of each connection.
+/*
+/*	smtp_sasl_start() performs per-session initialization. This
+/*	routine must be called once per session before doing any SASL
+/*	authentication. The sasl_opts_name and sasl_opts_val parameters are
+/*	the postfix configuration parameters setting the security
+/*	policy of the SASL authentication.
+/*
+/*	smtp_sasl_passwd_lookup() looks up the username/password
+/*	for the current SMTP server. The result is zero in case
+/*	of failure, a long jump in case of error.
+/*
+/*	smtp_sasl_authenticate() implements the SASL authentication
+/*	dialog. The result is < 0 in case of protocol failure, zero in
+/*	case of unsuccessful authentication, > 0 in case of success.
+/*	The why argument is updated with a reason for failure.
+/*	This routine must be called only when smtp_sasl_passwd_lookup()
+/*	succeeds.
+/*
+/*	smtp_sasl_cleanup() cleans up. It must be called at the
+/*	end of every SMTP session that uses SASL authentication.
+/*	This routine is a noop for non-SASL sessions.
+/*
+/*	smtp_sasl_passivate() appends flattened SASL attributes to the
+/*	specified buffer. The SASL attributes are not destroyed.
+/*
+/*	smtp_sasl_activate() restores SASL attributes from the
+/*	specified buffer. The buffer is modified. A result < 0
+/*	means there was an error.
+/*
+/*	Arguments:
+/* .IP session
+/*	Session context.
+/* .IP mech_list
+/*	String of SASL mechanisms (separated by blanks)
+/* DIAGNOSTICS
+/*	All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Original author:
+/*	Till Franke
+/*	SuSE Rhein/Main AG
+/*	65760 Eschborn, Germany
+/*
+/*	Adopted by:
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+#include <stdlib.h>
+#include <string.h>
+
+ /*
+  * Utility library
+  */
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+#include <split_at.h>
+
+ /*
+  * Global library
+  */
+#include <mail_params.h>
+#include <string_list.h>
+#include <maps.h>
+#include <mail_addr_find.h>
+#include <smtp_stream.h>
+
+ /*
+  * XSASL library.
+  */
+#include <xsasl.h>
+
+ /*
+  * Application-specific
+  */
+#include "smtp.h"
+#include "smtp_sasl.h"
+#include "smtp_sasl_auth_cache.h"
+
+#ifdef USE_SASL_AUTH
+
+ /*
+  * Per-host login/password information.
+  */
+static MAPS *smtp_sasl_passwd_map;
+
+ /*
+  * Supported SASL mechanisms.
+  */
+STRING_LIST *smtp_sasl_mechs;
+
+ /*
+  * SASL implementation handle.
+  */
+static XSASL_CLIENT_IMPL *smtp_sasl_impl;
+
+ /*
+  * The 535 SASL authentication failure cache.
+  */
+#ifdef HAVE_SASL_AUTH_CACHE
+static SMTP_SASL_AUTH_CACHE *smtp_sasl_auth_cache;
+
+#endif
+
+/* smtp_sasl_passwd_lookup - password lookup routine */
+
+int     smtp_sasl_passwd_lookup(SMTP_SESSION *session)
+{
+    const char *myname = "smtp_sasl_passwd_lookup";
+    SMTP_STATE *state = session->state;
+    SMTP_ITERATOR *iter = session->iterator;
+    const char *value;
+    char   *passwd;
+
+    /*
+     * Sanity check.
+     */
+    if (smtp_sasl_passwd_map == 0)
+	msg_panic("%s: passwd map not initialized", myname);
+
+    /*
+     * Look up the per-server password information. Try the hostname first,
+     * then try the destination.
+     * 
+     * XXX Instead of using nexthop (the intended destination) we use dest
+     * (either the intended destination, or a fall-back destination).
+     * 
+     * XXX SASL authentication currently depends on the host/domain but not on
+     * the TCP port. If the port is not :25, we should append it to the table
+     * lookup key. Code for this was briefly introduced into 2.2 snapshots,
+     * but didn't canonicalize the TCP port, and did not append the port to
+     * the MX hostname.
+     */
+    smtp_sasl_passwd_map->error = 0;
+    if ((smtp_mode
+	 && var_smtp_sender_auth && state->request->sender[0]
+	 && (value = mail_addr_find(smtp_sasl_passwd_map,
+				 state->request->sender, (char **) 0)) != 0)
+	|| (smtp_sasl_passwd_map->error == 0
+	    && (value = maps_find(smtp_sasl_passwd_map,
+				  STR(iter->host), 0)) != 0)
+	|| (smtp_sasl_passwd_map->error == 0
+	    && (value = maps_find(smtp_sasl_passwd_map,
+				  STR(iter->dest), 0)) != 0)) {
+	if (session->sasl_username)
+	    myfree(session->sasl_username);
+	session->sasl_username = mystrdup(value);
+	passwd = split_at(session->sasl_username, ':');
+	if (session->sasl_passwd)
+	    myfree(session->sasl_passwd);
+	session->sasl_passwd = mystrdup(passwd ? passwd : "");
+	if (msg_verbose)
+	    msg_info("%s: host `%s' user `%s' pass `%s'",
+		     myname, STR(iter->host),
+		     session->sasl_username, session->sasl_passwd);
+	return (1);
+    } else if (smtp_sasl_passwd_map->error) {
+	msg_warn("%s: %s lookup error",
+		 state->request->queue_id, smtp_sasl_passwd_map->title);
+	vstream_longjmp(session->stream, SMTP_ERR_DATA);
+    } else {
+	if (msg_verbose)
+	    msg_info("%s: no auth info found (sender=`%s', host=`%s')",
+		     myname, state->request->sender, STR(iter->host));
+	return (0);
+    }
+}
+
+/* smtp_sasl_initialize - per-process initialization (pre jail) */
+
+void    smtp_sasl_initialize(void)
+{
+
+    /*
+     * Sanity check.
+     */
+    if (smtp_sasl_passwd_map || smtp_sasl_impl)
+	msg_panic("smtp_sasl_initialize: repeated call");
+    if (*var_smtp_sasl_passwd == 0)
+	msg_fatal("specify a password table via the `%s' configuration parameter",
+		  VAR_LMTP_SMTP(SASL_PASSWD));
+
+    /*
+     * Open the per-host password table and initialize the SASL library. Use
+     * shared locks for reading, just in case someone updates the table.
+     */
+    smtp_sasl_passwd_map = maps_create(VAR_LMTP_SMTP(SASL_PASSWD),
+				       var_smtp_sasl_passwd,
+				       DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX
+				       | DICT_FLAG_UTF8_REQUEST);
+    if ((smtp_sasl_impl = xsasl_client_init(var_smtp_sasl_type,
+					    var_smtp_sasl_path)) == 0)
+	msg_fatal("SASL library initialization");
+
+    /*
+     * Initialize optional supported mechanism matchlist
+     */
+    if (*var_smtp_sasl_mechs)
+	smtp_sasl_mechs = string_list_init(VAR_SMTP_SASL_MECHS,
+					   MATCH_FLAG_NONE,
+					   var_smtp_sasl_mechs);
+
+    /*
+     * Initialize the 535 SASL authentication failure cache.
+     */
+    if (*var_smtp_sasl_auth_cache_name) {
+#ifdef HAVE_SASL_AUTH_CACHE
+	smtp_sasl_auth_cache =
+	    smtp_sasl_auth_cache_init(var_smtp_sasl_auth_cache_name,
+				      var_smtp_sasl_auth_cache_time);
+#else
+	msg_warn("not compiled with TLS support -- "
+	    "ignoring the %s setting", VAR_LMTP_SMTP(SASL_AUTH_CACHE_NAME));
+#endif
+    }
+}
+
+/* smtp_sasl_connect - per-session client initialization */
+
+void    smtp_sasl_connect(SMTP_SESSION *session)
+{
+
+    /*
+     * This initialization happens whenever we instantiate an SMTP session
+     * object. We don't instantiate a SASL client until we actually need one.
+     */
+    session->sasl_mechanism_list = 0;
+    session->sasl_username = 0;
+    session->sasl_passwd = 0;
+    session->sasl_client = 0;
+    session->sasl_reply = 0;
+}
+
+/* smtp_sasl_start - per-session SASL initialization */
+
+void    smtp_sasl_start(SMTP_SESSION *session, const char *sasl_opts_name,
+			        const char *sasl_opts_val)
+{
+    XSASL_CLIENT_CREATE_ARGS create_args;
+    SMTP_ITERATOR *iter = session->iterator;
+
+    if (msg_verbose)
+	msg_info("starting new SASL client");
+    if ((session->sasl_client =
+	 XSASL_CLIENT_CREATE(smtp_sasl_impl, &create_args,
+			     stream = session->stream,
+			     service = var_procname,
+			     server_name = STR(iter->host),
+			     security_options = sasl_opts_val)) == 0)
+	msg_fatal("SASL per-connection initialization failed");
+    session->sasl_reply = vstring_alloc(20);
+}
+
+/* smtp_sasl_authenticate - run authentication protocol */
+
+int     smtp_sasl_authenticate(SMTP_SESSION *session, DSN_BUF *why)
+{
+    const char *myname = "smtp_sasl_authenticate";
+    SMTP_ITERATOR *iter = session->iterator;
+    SMTP_RESP *resp;
+    const char *mechanism;
+    int     result;
+    char   *line;
+    int     steps = 0;
+
+    /*
+     * Sanity check.
+     */
+    if (session->sasl_mechanism_list == 0)
+	msg_panic("%s: no mechanism list", myname);
+
+    if (msg_verbose)
+	msg_info("%s: %s: SASL mechanisms %s",
+		 myname, session->namaddrport, session->sasl_mechanism_list);
+
+    /*
+     * Avoid repeated login failures after a recent 535 error.
+     */
+#ifdef HAVE_SASL_AUTH_CACHE
+    if (smtp_sasl_auth_cache
+	&& smtp_sasl_auth_cache_find(smtp_sasl_auth_cache, session)) {
+	char   *resp_dsn = smtp_sasl_auth_cache_dsn(smtp_sasl_auth_cache);
+	char   *resp_str = smtp_sasl_auth_cache_text(smtp_sasl_auth_cache);
+
+	if (var_smtp_sasl_auth_soft_bounce && resp_dsn[0] == '5')
+	    resp_dsn[0] = '4';
+	dsb_update(why, resp_dsn, DSB_DEF_ACTION, DSB_MTYPE_DNS,
+		   STR(iter->host), var_procname, resp_str,
+		   "SASL [CACHED] authentication failed; server %s said: %s",
+		   STR(iter->host), resp_str);
+	return (0);
+    }
+#endif
+
+    /*
+     * Start the client side authentication protocol.
+     */
+    result = xsasl_client_first(session->sasl_client,
+				session->sasl_mechanism_list,
+				session->sasl_username,
+				session->sasl_passwd,
+				&mechanism, session->sasl_reply);
+    if (result != XSASL_AUTH_OK) {
+	dsb_update(why, "4.7.0", DSB_DEF_ACTION, DSB_SKIP_RMTA,
+		   DSB_DTYPE_SASL, STR(session->sasl_reply),
+		   "SASL authentication failed; "
+		   "cannot authenticate to server %s: %s",
+		   session->namaddr, STR(session->sasl_reply));
+	return (-1);
+    }
+    /*-
+     * Send the AUTH command and the optional initial client response.
+     *
+     * https://tools.ietf.org/html/rfc4954#page-4
+     * Note that the AUTH command is still subject to the line length
+     * limitations defined in [SMTP].  If use of the initial response argument
+     * would cause the AUTH command to exceed this length, the client MUST NOT
+     * use the initial response parameter...
+     *
+     * https://tools.ietf.org/html/rfc5321#section-4.5.3.1.4
+     * The maximum total length of a command line including the command word
+     * and the <CRLF> is 512 octets.
+     *
+     * Defer the initial response if the resulting command exceeds the limit.
+     */
+    if (LEN(session->sasl_reply) > 0
+	&& strlen(mechanism) + LEN(session->sasl_reply) + 8 <= 512) {
+	smtp_chat_cmd(session, "AUTH %s %s", mechanism,
+		      STR(session->sasl_reply));
+	VSTRING_RESET(session->sasl_reply);	/* no deferred initial reply */
+    } else {
+	smtp_chat_cmd(session, "AUTH %s", mechanism);
+    }
+
+    /*
+     * Step through the authentication protocol until the server tells us
+     * that we are done.  If session->sasl_reply is non-empty we have a
+     * deferred initial reply and expect an empty initial challenge from the
+     * server. If the server's initial challenge is non-empty we have a SASL
+     * protocol violation with both sides wanting to go first.
+     */
+    while ((resp = smtp_chat_resp(session))->code / 100 == 3) {
+
+	/*
+	 * Sanity check.
+	 */
+	if (++steps > 100) {
+	    dsb_simple(why, "4.3.0", "SASL authentication failed; "
+		       "authentication protocol loop with server %s",
+		       session->namaddr);
+	    return (-1);
+	}
+
+	/*
+	 * Process a server challenge.
+	 */
+	line = resp->str;
+	(void) mystrtok(&line, "- \t\n");	/* skip over result code */
+
+	if (LEN(session->sasl_reply) > 0) {
+
+	    /*
+	     * Deferred initial response, the server challenge must be empty.
+	     * Cleared after actual transmission to the server.
+	     */
+	    if (*line) {
+		dsb_update(why, "4.7.0", DSB_DEF_ACTION,
+			   DSB_SKIP_RMTA, DSB_DTYPE_SASL, "protocol error",
+			   "SASL authentication failed; non-empty initial "
+			   "%s challenge from server %s: %s", mechanism,
+			   session->namaddr, STR(session->sasl_reply));
+		return (-1);
+	    }
+	} else {
+	    result = xsasl_client_next(session->sasl_client, line,
+				       session->sasl_reply);
+	    if (result != XSASL_AUTH_OK) {
+		dsb_update(why, "4.7.0", DSB_DEF_ACTION,	/* Fix 200512 */
+		    DSB_SKIP_RMTA, DSB_DTYPE_SASL, STR(session->sasl_reply),
+			   "SASL authentication failed; "
+			   "cannot authenticate to server %s: %s",
+			   session->namaddr, STR(session->sasl_reply));
+		return (-1);			/* Fix 200512 */
+	    }
+	}
+
+	/*
+	 * Send a client response.
+	 */
+	smtp_chat_cmd(session, "%s", STR(session->sasl_reply));
+	VSTRING_RESET(session->sasl_reply);	/* clear initial reply */
+    }
+
+    /*
+     * We completed the authentication protocol.
+     */
+    if (resp->code / 100 != 2) {
+#ifdef HAVE_SASL_AUTH_CACHE
+	/* Update the 535 authentication failure cache. */
+	if (smtp_sasl_auth_cache && resp->code == 535)
+	    smtp_sasl_auth_cache_store(smtp_sasl_auth_cache, session, resp);
+#endif
+	if (var_smtp_sasl_auth_soft_bounce && resp->code / 100 == 5)
+	    STR(resp->dsn_buf)[0] = '4';
+	dsb_update(why, resp->dsn, DSB_DEF_ACTION,
+		   DSB_MTYPE_DNS, STR(iter->host),
+		   var_procname, resp->str,
+		   "SASL authentication failed; server %s said: %s",
+		   session->namaddr, resp->str);
+	return (0);
+    }
+    return (1);
+}
+
+/* smtp_sasl_cleanup - per-session cleanup */
+
+void    smtp_sasl_cleanup(SMTP_SESSION *session)
+{
+    if (session->sasl_username) {
+	myfree(session->sasl_username);
+	session->sasl_username = 0;
+    }
+    if (session->sasl_passwd) {
+	myfree(session->sasl_passwd);
+	session->sasl_passwd = 0;
+    }
+    if (session->sasl_mechanism_list) {
+	/* allocated in smtp_sasl_helo_auth */
+	myfree(session->sasl_mechanism_list);
+	session->sasl_mechanism_list = 0;
+    }
+    if (session->sasl_client) {
+	if (msg_verbose)
+	    msg_info("disposing SASL state information");
+	xsasl_client_free(session->sasl_client);
+	session->sasl_client = 0;
+    }
+    if (session->sasl_reply) {
+	vstring_free(session->sasl_reply);
+	session->sasl_reply = 0;
+    }
+}
+
+/* smtp_sasl_passivate - append serialized SASL attributes */
+
+void    smtp_sasl_passivate(SMTP_SESSION *session, VSTRING *buf)
+{
+}
+
+/* smtp_sasl_activate - de-serialize SASL attributes */
+
+int     smtp_sasl_activate(SMTP_SESSION *session, char *buf)
+{
+    return (0);
+}
+
+#endif
diff --git a/src/smtp/smtp_sasl_proto.c b/src/smtp/smtp_sasl_proto.c
new file mode 100644
index 0000000..6a51696
--- /dev/null
+++ b/src/smtp/smtp_sasl_proto.c
@@ -0,0 +1,202 @@
+/*++
+/* NAME
+/*	smtp_sasl_proto 3
+/* SUMMARY
+/*	Postfix SASL interface for SMTP client
+/* SYNOPSIS
+/*	#include smtp_sasl.h
+/*
+/*	void	smtp_sasl_helo_auth(state, words)
+/*	SMTP_STATE *state;
+/*	const char *words;
+/*
+/*	int	smtp_sasl_helo_login(state)
+/*	SMTP_STATE *state;
+/* DESCRIPTION
+/*	This module contains random chunks of code that implement
+/*	the SMTP protocol interface for SASL negotiation. The goal
+/*	is to reduce clutter in the main SMTP client source code.
+/*
+/*	smtp_sasl_helo_auth() processes the AUTH option in the
+/*	SMTP server's EHLO response.
+/*
+/*	smtp_sasl_helo_login() authenticates the SMTP client to the
+/*	SMTP server, using the authentication mechanism information
+/*	given by the server. The result is a Postfix delivery status
+/*	code in case of trouble.
+/*
+/*	Arguments:
+/* .IP state
+/*	Session context.
+/* .IP words
+/*	List of SASL authentication mechanisms (separated by blanks)
+/* DIAGNOSTICS
+/*	All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Original author:
+/*	Till Franke
+/*	SuSE Rhein/Main AG
+/*	65760 Eschborn, Germany
+/*
+/*	Adopted by:
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <string.h>
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+#ifdef USE_SASL_AUTH
+
+/* smtp_sasl_compat_mechs - Trim server's mechanism list */
+
+static const char *smtp_sasl_compat_mechs(const char *words)
+{
+    static VSTRING *buf;
+    char   *mech_list;
+    char   *save_mech;
+    char   *mech;
+
+    /*
+     * Use server's mechanisms if no filter specified
+     */
+    if (smtp_sasl_mechs == 0 || *words == 0)
+	return (words);
+
+    if (buf == 0)
+	buf = vstring_alloc(10);
+
+    VSTRING_RESET(buf);
+    VSTRING_TERMINATE(buf);
+
+    save_mech = mech_list = mystrdup(words);
+
+    while ((mech = mystrtok(&mech_list, " \t")) != 0) {
+	if (string_list_match(smtp_sasl_mechs, mech)) {
+	    if (VSTRING_LEN(buf) > 0)
+		VSTRING_ADDCH(buf, ' ');
+	    vstring_strcat(buf, mech);
+	} else if (smtp_sasl_mechs->error) {
+	    msg_fatal("SASL mechanism filter failed for: '%s'", mech);
+	}
+    }
+    myfree(save_mech);
+
+    return (vstring_str(buf));
+}
+
+/* smtp_sasl_helo_auth - handle AUTH option in EHLO reply */
+
+void    smtp_sasl_helo_auth(SMTP_SESSION *session, const char *words)
+{
+    const char *mech_list = smtp_sasl_compat_mechs(words);
+    char   *junk;
+
+    /*
+     * XXX If the server offers no compatible authentication mechanisms, then
+     * pretend that the server doesn't support SASL authentication.
+     * 
+     * XXX If the server offers multiple different lists, concatenate them. Let
+     * the SASL library worry about duplicates.
+     */
+    if (session->sasl_mechanism_list) {
+	if (strcasecmp(session->sasl_mechanism_list, mech_list) != 0
+	    && strlen(mech_list) > 0
+	    && strlen(session->sasl_mechanism_list) < var_line_limit) {
+	    junk = concatenate(session->sasl_mechanism_list, " ", mech_list,
+			       (char *) 0);
+	    myfree(session->sasl_mechanism_list);
+	    session->sasl_mechanism_list = junk;
+	}
+	return;
+    }
+    if (strlen(mech_list) > 0) {
+	session->sasl_mechanism_list = mystrdup(mech_list);
+    } else {
+	msg_warn(*words ? "%s offered no supported AUTH mechanisms: '%s'" :
+		 "%s offered null AUTH mechanism list%s",
+		 session->namaddrport, words);
+    }
+    session->features |= SMTP_FEATURE_AUTH;
+}
+
+/* smtp_sasl_helo_login - perform SASL login */
+
+int     smtp_sasl_helo_login(SMTP_STATE *state)
+{
+    SMTP_SESSION *session = state->session;
+    DSN_BUF *why = state->why;
+    int     ret;
+
+    /*
+     * Skip authentication when no authentication info exists for this
+     * server, so that we talk to each other like strangers.
+     */
+    if (smtp_sasl_passwd_lookup(session) == 0) {
+	session->features &= ~SMTP_FEATURE_AUTH;
+	return 0;
+    }
+
+    /*
+     * Otherwise, if authentication information exists, assume that
+     * authentication is required, and assume that an authentication error is
+     * recoverable from the message delivery point of view. An authentication
+     * error is unrecoverable from a session point of view - the session will
+     * not be reused.
+     */
+    ret = 0;
+    if (session->sasl_mechanism_list == 0) {
+	dsb_simple(why, "4.7.0", "SASL authentication failed: "
+		   "server %s offered no compatible authentication mechanisms for this type of connection security",
+		   session->namaddr);
+	ret = smtp_sess_fail(state);
+	/* Session reuse is disabled. */
+    } else {
+#ifndef USE_TLS
+	smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_OPTS), var_smtp_sasl_opts);
+#else
+	if (session->tls_context == 0)
+	    smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_OPTS),
+			    var_smtp_sasl_opts);
+	else if (TLS_CERT_IS_MATCHED(session->tls_context))
+	    smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_TLSV_OPTS),
+			    var_smtp_sasl_tlsv_opts);
+	else
+	    smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_TLS_OPTS),
+			    var_smtp_sasl_tls_opts);
+#endif
+	if (smtp_sasl_authenticate(session, why) <= 0) {
+	    ret = smtp_sess_fail(state);
+	    /* Session reuse is disabled. */
+	}
+    }
+    return (ret);
+}
+
+#endif
diff --git a/src/smtp/smtp_session.c b/src/smtp/smtp_session.c
new file mode 100644
index 0000000..1b3a20e
--- /dev/null
+++ b/src/smtp/smtp_session.c
@@ -0,0 +1,446 @@
+/*++
+/* NAME
+/*	smtp_session 3
+/* SUMMARY
+/*	SMTP_SESSION structure management
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	SMTP_SESSION *smtp_session_alloc(stream, iter, start, flags)
+/*	VSTREAM	*stream;
+/*	SMTP_ITERATOR *iter;
+/*	time_t	start;
+/*	int	flags;
+/*
+/*	void	smtp_session_free(session)
+/*	SMTP_SESSION *session;
+/*
+/*	int	smtp_session_passivate(session, dest_prop, endp_prop)
+/*	SMTP_SESSION *session;
+/*	VSTRING	*dest_prop;
+/*	VSTRING	*endp_prop;
+/*
+/*	SMTP_SESSION *smtp_session_activate(fd, iter, dest_prop, endp_prop)
+/*	int	fd;
+/*	SMTP_ITERATOR *iter;
+/*	VSTRING	*dest_prop;
+/*	VSTRING	*endp_prop;
+/* DESCRIPTION
+/*	smtp_session_alloc() allocates memory for an SMTP_SESSION structure
+/*	and initializes it with the given stream and destination, host name
+/*	and address information.  The host name and address strings are
+/*	copied. The port is in network byte order.
+/*
+/*	smtp_session_free() destroys an SMTP_SESSION structure and its
+/*	members, making memory available for reuse. It will handle the
+/*	case of a null stream and will assume it was given a different
+/*	purpose.
+/*
+/*	smtp_session_passivate() flattens an SMTP session (including
+/*	TLS context) so that it can be cached. The SMTP_SESSION
+/*	structure is destroyed.
+/*
+/*	smtp_session_activate() inflates a flattened SMTP session
+/*	so that it can be used. The input property arguments are
+/*	modified.
+/*
+/*	Arguments:
+/* .IP stream
+/*	A full-duplex stream.
+/* .IP iter
+/*	The literal next-hop or fall-back destination including
+/*	the optional [] and including the :port or :service;
+/*	the name of the remote host;
+/*	the printable address of the remote host;
+/*	the remote port in network byte order.
+/* .IP start
+/*	The time when this connection was opened.
+/* .IP flags
+/*	Zero or more of the following:
+/* .RS
+/* .IP SMTP_MISC_FLAG_CONN_LOAD
+/*	Enable re-use of cached SMTP or LMTP connections.
+/* .IP SMTP_MISC_FLAG_CONN_STORE
+/*	Enable saving of cached SMTP or LMTP connections.
+/* .RE
+/*	SMTP_MISC_FLAG_CONN_MASK corresponds with both _LOAD and _STORE.
+/* .IP dest_prop
+/*	Destination specific session properties: the server is the
+/*	best MX host for the current logical destination, the dest,
+/*	host, and addr properties. When dest_prop is non-empty, it
+/*	overrides the iterator dest, host, and addr properties.  It
+/*	is the caller's responsibility to save the current nexthop
+/*	with SMTP_ITER_SAVE_DEST() and to restore it afterwards
+/*	with SMTP_ITER_RESTORE_DEST() before trying alternatives.
+/* .IP endp_prop
+/*	Endpoint specific session properties: all the features
+/*	advertised by the remote server.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	Viktor Dukhovni
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <stdlib.h>
+#include <string.h>
+#include <netinet/in.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <mime_state.h>
+#include <debug_peer.h>
+#include <mail_params.h>
+
+/* TLS Library. */
+
+#include <tls_proxy.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+ /*
+  * Local, because these are meaningful only for code in this file.
+  */
+#define SESS_ATTR_DEST		"destination"
+#define SESS_ATTR_HOST		"host_name"
+#define SESS_ATTR_ADDR		"host_addr"
+#define SESS_ATTR_DEST_FEATURES	"destination_features"
+
+#define SESS_ATTR_TLS_LEVEL	"tls_level"
+#define SESS_ATTR_REUSE_COUNT	"reuse_count"
+#define SESS_ATTR_ENDP_FEATURES	"endpoint_features"
+#define SESS_ATTR_EXPIRE_TIME	"expire_time"
+
+/* smtp_session_alloc - allocate and initialize SMTP_SESSION structure */
+
+SMTP_SESSION *smtp_session_alloc(VSTREAM *stream, SMTP_ITERATOR *iter,
+				         time_t start, int flags)
+{
+    SMTP_SESSION *session;
+    const char *host = STR(iter->host);
+    const char *addr = STR(iter->addr);
+    unsigned port = iter->port;
+
+    session = (SMTP_SESSION *) mymalloc(sizeof(*session));
+    session->stream = stream;
+    session->iterator = iter;
+    session->namaddr = concatenate(host, "[", addr, "]", (char *) 0);
+    session->helo = 0;
+    session->port = port;
+    session->features = 0;
+
+    session->size_limit = 0;
+    session->error_mask = 0;
+    session->buffer = vstring_alloc(100);
+    session->scratch = vstring_alloc(100);
+    session->scratch2 = vstring_alloc(100);
+    smtp_chat_init(session);
+    session->mime_state = 0;
+
+    if (session->port) {
+	vstring_sprintf(session->buffer, "%s:%d",
+			session->namaddr, ntohs(session->port));
+	session->namaddrport = mystrdup(STR(session->buffer));
+    } else
+	session->namaddrport = mystrdup(session->namaddr);
+
+    session->send_proto_helo = 0;
+
+    if (flags & SMTP_MISC_FLAG_CONN_STORE)
+	CACHE_THIS_SESSION_UNTIL(start + var_smtp_reuse_time);
+    else
+	DONT_CACHE_THIS_SESSION;
+    session->reuse_count = 0;
+    USE_NEWBORN_SESSION;			/* He's not dead Jim! */
+
+#ifdef USE_SASL_AUTH
+    smtp_sasl_connect(session);
+#endif
+
+#ifdef USE_TLS
+    session->tls_context = 0;
+    session->tls_retry_plain = 0;
+    session->tls_nexthop = 0;
+#endif
+    session->state = 0;
+    debug_peer_check(host, addr);
+    return (session);
+}
+
+/* smtp_session_free - destroy SMTP_SESSION structure and contents */
+
+void    smtp_session_free(SMTP_SESSION *session)
+{
+#ifdef USE_TLS
+    if (session->stream) {
+	vstream_fflush(session->stream);
+    }
+    if (session->tls_context) {
+	if (session->features &
+	    (SMTP_FEATURE_FROM_CACHE | SMTP_FEATURE_FROM_PROXY))
+	    tls_proxy_context_free(session->tls_context);
+	else
+	    tls_client_stop(smtp_tls_ctx, session->stream,
+			  var_smtp_starttls_tmout, 0, session->tls_context);
+    }
+#endif
+    if (session->stream)
+	vstream_fclose(session->stream);
+    myfree(session->namaddr);
+    myfree(session->namaddrport);
+    if (session->helo)
+	myfree(session->helo);
+
+    vstring_free(session->buffer);
+    vstring_free(session->scratch);
+    vstring_free(session->scratch2);
+
+    if (session->history)
+	smtp_chat_reset(session);
+    if (session->mime_state)
+	mime_state_free(session->mime_state);
+
+#ifdef USE_SASL_AUTH
+    smtp_sasl_cleanup(session);
+#endif
+
+    debug_peer_restore();
+    myfree((void *) session);
+}
+
+/* smtp_session_passivate - passivate an SMTP_SESSION object */
+
+int     smtp_session_passivate(SMTP_SESSION *session, VSTRING *dest_prop,
+			               VSTRING *endp_prop)
+{
+    SMTP_ITERATOR *iter = session->iterator;
+    VSTREAM *mp;
+    int     fd;
+
+    /*
+     * Encode the delivery request next-hop to endpoint binding properties:
+     * whether or not this server is best MX host for the delivery request
+     * next-hop or fall-back logical destination (this information is needed
+     * for loop handling in smtp_proto()).
+     * 
+     * TODO: save SASL username and password information so that we can
+     * correctly save a reused authenticated connection.
+     * 
+     * These memory writes should never fail.
+     */
+    if ((mp = vstream_memopen(dest_prop, O_WRONLY)) == 0
+	|| attr_print_plain(mp, ATTR_FLAG_NONE,
+			    SEND_ATTR_STR(SESS_ATTR_DEST, STR(iter->dest)),
+			    SEND_ATTR_STR(SESS_ATTR_HOST, STR(iter->host)),
+			    SEND_ATTR_STR(SESS_ATTR_ADDR, STR(iter->addr)),
+			    SEND_ATTR_INT(SESS_ATTR_DEST_FEATURES,
+			 session->features & SMTP_FEATURE_DESTINATION_MASK),
+			    ATTR_TYPE_END) != 0
+	|| vstream_fclose(mp) != 0)
+	msg_fatal("smtp_session_passivate: can't save dest properties: %m");
+
+    /*
+     * Encode the physical endpoint properties: all the session properties
+     * except for "session from cache", "best MX", or "RSET failure". Plus
+     * the TLS level, reuse count, and connection expiration time.
+     * 
+     * XXX Should also record how many non-delivering mail transactions there
+     * were during this session, and perhaps other statistics, so that we
+     * don't reuse a session too much.
+     * 
+     * TODO: passivate SASL username and password information so that we can
+     * correctly save a reused authenticated connection.
+     * 
+     * These memory writes should never fail.
+     */
+    if ((mp = vstream_memopen(endp_prop, O_WRONLY)) == 0
+	|| attr_print_plain(mp, ATTR_FLAG_NONE,
+#ifdef USE_TLS
+			    SEND_ATTR_INT(SESS_ATTR_TLS_LEVEL,
+					  session->state->tls->level),
+#endif
+			    SEND_ATTR_INT(SESS_ATTR_REUSE_COUNT,
+					  session->reuse_count),
+			    SEND_ATTR_INT(SESS_ATTR_ENDP_FEATURES,
+			    session->features & SMTP_FEATURE_ENDPOINT_MASK),
+			    SEND_ATTR_LONG(SESS_ATTR_EXPIRE_TIME,
+					   (long) session->expire_time),
+			    ATTR_TYPE_END) != 0
+
+    /*
+     * Append the passivated TLS context. These memory writes should never
+     * fail.
+     */
+#ifdef USE_TLS
+	|| (session->tls_context
+	    && attr_print_plain(mp, ATTR_FLAG_NONE,
+				SEND_ATTR_FUNC(tls_proxy_context_print,
+					     (void *) session->tls_context),
+				ATTR_TYPE_END) != 0)
+#endif
+	|| vstream_fclose(mp) != 0)
+	msg_fatal("smtp_session_passivate: cannot save TLS context: %m");
+
+    /*
+     * Salvage the underlying file descriptor, and destroy the session
+     * object.
+     */
+    fd = vstream_fileno(session->stream);
+    vstream_fdclose(session->stream);
+    session->stream = 0;
+    smtp_session_free(session);
+
+    return (fd);
+}
+
+/* smtp_session_activate - re-activate a passivated SMTP_SESSION object */
+
+SMTP_SESSION *smtp_session_activate(int fd, SMTP_ITERATOR *iter,
+				            VSTRING *dest_prop,
+				            VSTRING *endp_prop)
+{
+    const char *myname = "smtp_session_activate";
+    VSTREAM *mp;
+    SMTP_SESSION *session;
+    int     endp_features;		/* server features */
+    int     dest_features;		/* server features */
+    long    expire_time;		/* session re-use expiration time */
+    int     reuse_count;		/* # times reused */
+
+#ifdef USE_TLS
+    TLS_SESS_STATE *tls_context = 0;
+    SMTP_TLS_POLICY *tls = iter->parent->tls;
+
+#define TLS_PROXY_CONTEXT_FREE() do { \
+    if (tls_context) \
+	tls_proxy_context_free(tls_context); \
+   } while (0)
+#else
+#define TLS_PROXY_CONTEXT_FREE()		/* nothing */
+#endif
+
+#define SMTP_SESSION_ACTIVATE_ERR_RETURN() do { \
+	TLS_PROXY_CONTEXT_FREE(); \
+	return (0); \
+   } while (0)
+
+    /*
+     * Sanity check: if TLS is required, the cached properties must contain a
+     * TLS context.
+     */
+    if ((mp = vstream_memopen(endp_prop, O_RDONLY)) == 0
+	|| attr_scan_plain(mp, ATTR_FLAG_NONE,
+#ifdef USE_TLS
+			   RECV_ATTR_INT(SESS_ATTR_TLS_LEVEL,
+					 &tls->level),
+#endif
+			   RECV_ATTR_INT(SESS_ATTR_REUSE_COUNT,
+					 &reuse_count),
+			   RECV_ATTR_INT(SESS_ATTR_ENDP_FEATURES,
+					 &endp_features),
+			   RECV_ATTR_LONG(SESS_ATTR_EXPIRE_TIME,
+					  &expire_time),
+			   ATTR_TYPE_END) != 4
+#ifdef USE_TLS
+	|| ((tls->level > TLS_LEV_MAY
+	     || (tls->level == TLS_LEV_MAY && vstream_peek(mp) > 0))
+	    && attr_scan_plain(mp, ATTR_FLAG_NONE,
+			       RECV_ATTR_FUNC(tls_proxy_context_scan,
+					      (void *) &tls_context),
+			       ATTR_TYPE_END) != 1)
+#endif
+	|| vstream_fclose(mp) != 0) {
+	msg_warn("smtp_session_activate: bad cached endp properties");
+	SMTP_SESSION_ACTIVATE_ERR_RETURN();
+    }
+
+    /*
+     * Clobber the iterator's current nexthop, host and address fields with
+     * cached-connection information. This is done when a session is looked
+     * up by delivery request nexthop instead of address and port. It is the
+     * caller's responsibility to save and restore the delivery request
+     * nexthop with SMTP_ITER_SAVE_DEST() and SMTP_ITER_RESTORE_DEST().
+     * 
+     * TODO: Eliminate the duplication between SMTP_ITERATOR and SMTP_SESSION.
+     * 
+     * TODO: restore SASL username and password information so that we can
+     * correctly save a reused authenticated connection.
+     */
+    if (dest_prop && VSTRING_LEN(dest_prop)) {
+	if ((mp = vstream_memopen(dest_prop, O_RDONLY)) == 0
+	    || attr_scan_plain(mp, ATTR_FLAG_NONE,
+			       RECV_ATTR_STR(SESS_ATTR_DEST, iter->dest),
+			       RECV_ATTR_STR(SESS_ATTR_HOST, iter->host),
+			       RECV_ATTR_STR(SESS_ATTR_ADDR, iter->addr),
+			       RECV_ATTR_INT(SESS_ATTR_DEST_FEATURES,
+					     &dest_features),
+			       ATTR_TYPE_END) != 4
+	    || vstream_fclose(mp) != 0) {
+	    msg_warn("smtp_session_passivate: bad cached dest properties");
+	    SMTP_SESSION_ACTIVATE_ERR_RETURN();
+	}
+    } else {
+	dest_features = 0;
+    }
+#ifdef USE_TLS
+    if (msg_verbose)
+	msg_info("%s: tls_level=%d", myname, tls->level);
+#endif
+
+    /*
+     * Allright, bundle up what we have sofar.
+     */
+#define NO_FLAGS	0
+
+    session = smtp_session_alloc(vstream_fdopen(fd, O_RDWR), iter,
+				 (time_t) 0, NO_FLAGS);
+    session->features =
+	(endp_features | dest_features | SMTP_FEATURE_FROM_CACHE);
+#ifdef USE_TLS
+    session->tls_context = tls_context;
+#endif
+    CACHE_THIS_SESSION_UNTIL(expire_time);
+    session->reuse_count = ++reuse_count;
+
+    if (msg_verbose)
+	msg_info("%s: dest=%s host=%s addr=%s port=%u features=0x%x, "
+		 "ttl=%ld, reuse=%d",
+		 myname, STR(iter->dest), STR(iter->host),
+		 STR(iter->addr), ntohs(iter->port),
+		 endp_features | dest_features,
+		 (long) (expire_time - time((time_t *) 0)),
+		 reuse_count);
+
+#if USE_TLS
+    if (tls_context)
+	tls_log_summary(TLS_ROLE_CLIENT, TLS_USAGE_USED,
+			session->tls_context);
+#endif
+
+    return (session);
+}
diff --git a/src/smtp/smtp_state.c b/src/smtp/smtp_state.c
new file mode 100644
index 0000000..f91ab8c
--- /dev/null
+++ b/src/smtp/smtp_state.c
@@ -0,0 +1,114 @@
+/*++
+/* NAME
+/*	smtp_state 3
+/* SUMMARY
+/*	initialize/cleanup shared state
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	SMTP_STATE *smtp_state_alloc()
+/*
+/*	void	smtp_state_free(state)
+/*	SMTP_STATE *state;
+/* DESCRIPTION
+/*	smtp_state_init() initializes the shared state, and allocates
+/*	memory for buffers etc.
+/*
+/*	smtp_cleanup() destroys memory allocated by smtp_state_init().
+/* STANDARDS
+/* DIAGNOSTICS
+/* BUGS
+/* SEE ALSO
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+
+/* Utility library. */
+
+#include <mymalloc.h>
+#include <vstring.h>
+#include <msg.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+/* smtp_state_alloc - initialize */
+
+SMTP_STATE *smtp_state_alloc(void)
+{
+    SMTP_STATE *state = (SMTP_STATE *) mymalloc(sizeof(*state));
+
+    state->misc_flags = 0;
+    state->src = 0;
+    state->service = 0;
+    state->request = 0;
+    state->session = 0;
+    state->status = 0;
+    state->space_left = 0;
+    state->iterator->request_nexthop = vstring_alloc(100);
+    state->iterator->dest = vstring_alloc(100);
+    state->iterator->host = vstring_alloc(100);
+    state->iterator->addr = vstring_alloc(100);
+    state->iterator->saved_dest = vstring_alloc(100);
+    if (var_smtp_cache_conn) {
+	state->dest_label = vstring_alloc(10);
+	state->dest_prop = vstring_alloc(10);
+	state->endp_label = vstring_alloc(10);
+	state->endp_prop = vstring_alloc(10);
+	state->cache_used = htable_create(1);
+    } else {
+	state->dest_label = 0;
+	state->dest_prop = 0;
+	state->endp_label = 0;
+	state->endp_prop = 0;
+	state->cache_used = 0;
+    }
+    state->why = dsb_create();
+    return (state);
+}
+
+/* smtp_state_free - destroy state */
+
+void    smtp_state_free(SMTP_STATE *state)
+{
+#ifdef USE_TLS
+    /* The TLS policy cache lifetime is one delivery. */
+    smtp_tls_policy_cache_flush();
+#endif
+    vstring_free(state->iterator->request_nexthop);
+    vstring_free(state->iterator->dest);
+    vstring_free(state->iterator->host);
+    vstring_free(state->iterator->addr);
+    vstring_free(state->iterator->saved_dest);
+    if (state->dest_label)
+	vstring_free(state->dest_label);
+    if (state->dest_prop)
+	vstring_free(state->dest_prop);
+    if (state->endp_label)
+	vstring_free(state->endp_label);
+    if (state->endp_prop)
+	vstring_free(state->endp_prop);
+    if (state->cache_used)
+	htable_free(state->cache_used, (void (*) (void *)) 0);
+    if (state->why)
+	dsb_free(state->why);
+
+    myfree((void *) state);
+}
diff --git a/src/smtp/smtp_tls_policy.c b/src/smtp/smtp_tls_policy.c
new file mode 100644
index 0000000..4b394a9
--- /dev/null
+++ b/src/smtp/smtp_tls_policy.c
@@ -0,0 +1,928 @@
+/*++
+/* NAME
+/*	smtp_tls_policy 3
+/* SUMMARY
+/*	SMTP_TLS_POLICY structure management
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	void    smtp_tls_list_init()
+/*
+/*	int	smtp_tls_policy_cache_query(why, tls, iter)
+/*	DSN_BUF	*why;
+/*	SMTP_TLS_POLICY *tls;
+/*	SMTP_ITERATOR *iter;
+/*
+/*	void	smtp_tls_policy_dummy(tls)
+/*	SMTP_TLS_POLICY *tls;
+/*
+/*	void	smtp_tls_policy_cache_flush()
+/* DESCRIPTION
+/*	smtp_tls_list_init() initializes lookup tables used by the TLS
+/*	policy engine.
+/*
+/*	smtp_tls_policy_cache_query() returns a shallow copy of the
+/*	cached SMTP_TLS_POLICY structure for the iterator's
+/*	destination, host, port and DNSSEC validation status.
+/*	This copy is guaranteed to be valid until the next
+/*	smtp_tls_policy_cache_query() or smtp_tls_policy_cache_flush()
+/*	call.  The caller can override the TLS security level without
+/*	corrupting the policy cache.
+/*	When any required table or DNS lookups fail, the TLS level
+/*	is set to TLS_LEV_INVALID, the "why" argument is updated
+/*	with the error reason and the result value is zero (false).
+/*
+/*	smtp_tls_policy_dummy() initializes a trivial, non-cached,
+/*	policy with TLS disabled.
+/*
+/*	smtp_tls_policy_cache_flush() destroys the TLS policy cache
+/*	and contents.
+/*
+/*	Arguments:
+/* .IP why
+/*	A pointer to a DSN_BUF which holds error status information when
+/*	the TLS policy lookup fails.
+/* .IP tls
+/*	Pointer to TLS policy storage.
+/* .IP iter
+/*	The literal next-hop or fall-back destination including
+/*	the optional [] and including the :port or :service;
+/*	the name of the remote host after MX and CNAME expansions
+/*	(see smtp_cname_overrides_servername for the handling
+/*	of hostnames that resolve to a CNAME record);
+/*	the printable address of the remote host;
+/*	the remote port in network byte order;
+/*	the DNSSEC validation status of the host name lookup after
+/*	MX and CNAME expansions.
+/* LICENSE
+/* .ad
+/* .fi
+/*	This software is free. You can do with it whatever you want.
+/*	The original author kindly requests that you acknowledge
+/*	the use of his software.
+/* AUTHOR(S)
+/*	TLS support originally by:
+/*	Lutz Jaenicke
+/*	BTU Cottbus
+/*	Allgemeine Elektrotechnik
+/*	Universitaetsplatz 3-4
+/*	D-03044 Cottbus, Germany
+/*
+/*	Updated by:
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	Viktor Dukhovni
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+
+#ifdef USE_TLS
+
+#include <netinet/in.h>			/* ntohs() for Solaris or BSD */
+#include <arpa/inet.h>			/* ntohs() for Linux or BSD */
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstring.h>
+#include <stringops.h>
+#include <valid_hostname.h>
+#include <valid_utf8_hostname.h>
+#include <ctable.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <maps.h>
+#include <dsn_buf.h>
+
+/* DNS library. */
+
+#include <dns.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+
+/* XXX Cache size should scale with [sl]mtp_mx_address_limit. */
+#define CACHE_SIZE 20
+static CTABLE *policy_cache;
+
+static int global_tls_level(void);
+static void dane_init(SMTP_TLS_POLICY *, SMTP_ITERATOR *);
+
+static MAPS *tls_policy;		/* lookup table(s) */
+static MAPS *tls_per_site;		/* lookup table(s) */
+
+/* smtp_tls_list_init - initialize per-site policy lists */
+
+void    smtp_tls_list_init(void)
+{
+    if (*var_smtp_tls_policy) {
+	tls_policy = maps_create(VAR_LMTP_SMTP(TLS_POLICY),
+				 var_smtp_tls_policy,
+				 DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX
+				 | DICT_FLAG_UTF8_REQUEST);
+	if (*var_smtp_tls_per_site)
+	    msg_warn("%s ignored when %s is not empty.",
+		     VAR_LMTP_SMTP(TLS_PER_SITE), VAR_LMTP_SMTP(TLS_POLICY));
+	return;
+    }
+    if (*var_smtp_tls_per_site) {
+	tls_per_site = maps_create(VAR_LMTP_SMTP(TLS_PER_SITE),
+				   var_smtp_tls_per_site,
+				   DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX
+				   | DICT_FLAG_UTF8_REQUEST);
+    }
+}
+
+/* policy_name - printable tls policy level */
+
+static const char *policy_name(int tls_level)
+{
+    const char *name = str_tls_level(tls_level);
+
+    if (name == 0)
+	name = "unknown";
+    return name;
+}
+
+#define MARK_INVALID(why, levelp) do { \
+	    dsb_simple((why), "4.7.5", "client TLS configuration problem"); \
+	    *(levelp) = TLS_LEV_INVALID; } while (0)
+
+/* tls_site_lookup - look up per-site TLS security level */
+
+static void tls_site_lookup(SMTP_TLS_POLICY *tls, int *site_level,
+		              const char *site_name, const char *site_class)
+{
+    const char *lookup;
+
+    /*
+     * Look up a non-default policy. In case of multiple lookup results, the
+     * precedence order is a permutation of the TLS enforcement level order:
+     * VERIFY, ENCRYPT, NONE, MAY, NOTFOUND. I.e. we override MAY with a more
+     * specific policy including NONE, otherwise we choose the stronger
+     * enforcement level.
+     */
+    if ((lookup = maps_find(tls_per_site, site_name, 0)) != 0) {
+	if (!strcasecmp(lookup, "NONE")) {
+	    /* NONE overrides MAY or NOTFOUND. */
+	    if (*site_level <= TLS_LEV_MAY)
+		*site_level = TLS_LEV_NONE;
+	} else if (!strcasecmp(lookup, "MAY")) {
+	    /* MAY overrides NOTFOUND but not NONE. */
+	    if (*site_level < TLS_LEV_NONE)
+		*site_level = TLS_LEV_MAY;
+	} else if (!strcasecmp(lookup, "MUST_NOPEERMATCH")) {
+	    if (*site_level < TLS_LEV_ENCRYPT)
+		*site_level = TLS_LEV_ENCRYPT;
+	} else if (!strcasecmp(lookup, "MUST")) {
+	    if (*site_level < TLS_LEV_VERIFY)
+		*site_level = TLS_LEV_VERIFY;
+	} else {
+	    msg_warn("%s: unknown TLS policy '%s' for %s %s",
+		     tls_per_site->title, lookup, site_class, site_name);
+	    MARK_INVALID(tls->why, site_level);
+	    return;
+	}
+    } else if (tls_per_site->error) {
+	msg_warn("%s: %s \"%s\": per-site table lookup error",
+		 tls_per_site->title, site_class, site_name);
+	dsb_simple(tls->why, "4.3.0", "Temporary lookup error");
+	*site_level = TLS_LEV_INVALID;
+	return;
+    }
+    return;
+}
+
+/* tls_policy_lookup_one - look up destination TLS policy */
+
+static void tls_policy_lookup_one(SMTP_TLS_POLICY *tls, int *site_level,
+				          const char *site_name,
+				          const char *site_class)
+{
+    const char *lookup;
+    char   *policy;
+    char   *saved_policy;
+    char   *tok;
+    const char *err;
+    char   *name;
+    char   *val;
+    static VSTRING *cbuf;
+
+#undef FREE_RETURN
+#define FREE_RETURN do { myfree(saved_policy); return; } while (0)
+
+#define INVALID_RETURN(why, levelp) do { \
+	    MARK_INVALID((why), (levelp)); FREE_RETURN; } while (0)
+
+#define WHERE \
+    STR(vstring_sprintf(cbuf, "%s, %s \"%s\"", \
+		tls_policy->title, site_class, site_name))
+
+    if (cbuf == 0)
+	cbuf = vstring_alloc(10);
+
+    if ((lookup = maps_find(tls_policy, site_name, 0)) == 0) {
+	if (tls_policy->error) {
+	    msg_warn("%s: policy table lookup error", WHERE);
+	    MARK_INVALID(tls->why, site_level);
+	}
+	return;
+    }
+    saved_policy = policy = mystrdup(lookup);
+
+    if ((tok = mystrtok(&policy, CHARS_COMMA_SP)) == 0) {
+	msg_warn("%s: invalid empty policy", WHERE);
+	INVALID_RETURN(tls->why, site_level);
+    }
+    *site_level = tls_level_lookup(tok);
+    if (*site_level == TLS_LEV_INVALID) {
+	/* tls_level_lookup() logs no warning. */
+	msg_warn("%s: invalid security level \"%s\"", WHERE, tok);
+	INVALID_RETURN(tls->why, site_level);
+    }
+
+    /*
+     * Warn about ignored attributes when TLS is disabled.
+     */
+    if (*site_level < TLS_LEV_MAY) {
+	while ((tok = mystrtok(&policy, CHARS_COMMA_SP)) != 0)
+	    msg_warn("%s: ignoring attribute \"%s\" with TLS disabled",
+		     WHERE, tok);
+	FREE_RETURN;
+    }
+
+    /*
+     * Errors in attributes may have security consequences, don't ignore
+     * errors that can degrade security.
+     */
+    while ((tok = mystrtok(&policy, CHARS_COMMA_SP)) != 0) {
+	if ((err = split_nameval(tok, &name, &val)) != 0) {
+	    msg_warn("%s: malformed attribute/value pair \"%s\": %s",
+		     WHERE, tok, err);
+	    INVALID_RETURN(tls->why, site_level);
+	}
+	/* Only one instance per policy. */
+	if (!strcasecmp(name, "ciphers")) {
+	    if (*val == 0) {
+		msg_warn("%s: attribute \"%s\" has empty value", WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    if (tls->grade) {
+		msg_warn("%s: attribute \"%s\" is specified multiple times",
+			 WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    tls->grade = mystrdup(val);
+	    continue;
+	}
+	/* Only one instance per policy. */
+	if (!strcasecmp(name, "protocols")) {
+	    if (tls->protocols) {
+		msg_warn("%s: attribute \"%s\" is specified multiple times",
+			 WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    tls->protocols = mystrdup(val);
+	    continue;
+	}
+	/* Only one instance per policy. */
+	if (!strcasecmp(name, "servername")) {
+	    if (tls->sni) {
+		msg_warn("%s: attribute \"%s\" is specified multiple times",
+			 WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    if (valid_hostname(val, DONT_GRIPE))
+		tls->sni = mystrdup(val);
+	    else {
+		msg_warn("%s: \"%s=%s\" specifies an invalid hostname",
+			 WHERE, name, val);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    continue;
+	}
+	/* Multiple instances per policy. */
+	if (!strcasecmp(name, "match")) {
+	    if (*val == 0) {
+		msg_warn("%s: attribute \"%s\" has empty value", WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    switch (*site_level) {
+	    default:
+		msg_warn("%s: attribute \"%s\" invalid at security level "
+			 "\"%s\"", WHERE, name, policy_name(*site_level));
+		INVALID_RETURN(tls->why, site_level);
+		break;
+	    case TLS_LEV_FPRINT:
+		if (!tls->dane)
+		    tls->dane = tls_dane_alloc();
+		tls_dane_add_ee_digests(tls->dane,
+					var_smtp_tls_fpt_dgst, val, "|");
+		break;
+	    case TLS_LEV_VERIFY:
+	    case TLS_LEV_SECURE:
+		if (tls->matchargv == 0)
+		    tls->matchargv = argv_split(val, ":");
+		else
+		    argv_split_append(tls->matchargv, val, ":");
+		break;
+	    }
+	    continue;
+	}
+	/* Only one instance per policy. */
+	if (!strcasecmp(name, "exclude")) {
+	    if (tls->exclusions) {
+		msg_warn("%s: attribute \"%s\" is specified multiple times",
+			 WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    tls->exclusions = vstring_strcpy(vstring_alloc(10), val);
+	    continue;
+	}
+	/* Multiple instances per policy. */
+	if (!strcasecmp(name, "tafile")) {
+	    /* Only makes sense if we're using CA-based trust */
+	    if (!TLS_MUST_PKIX(*site_level)) {
+		msg_warn("%s: attribute \"%s\" invalid at security level"
+			 " \"%s\"", WHERE, name, policy_name(*site_level));
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    if (*val == 0) {
+		msg_warn("%s: attribute \"%s\" has empty value", WHERE, name);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    if (!tls->dane)
+		tls->dane = tls_dane_alloc();
+	    if (!tls_dane_load_trustfile(tls->dane, val)) {
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    continue;
+	}
+	/* Last one wins. */
+	if (!strcasecmp(name, "connection_reuse")) {
+	    if (strcasecmp(val, "yes") == 0) {
+		tls->conn_reuse = 1;
+	    } else if (strcasecmp(val, "no") == 0) {
+		tls->conn_reuse = 0;
+	    } else {
+		msg_warn("%s: attribute \"%s\" has bad value: \"%s\"",
+			 WHERE, name, val);
+		INVALID_RETURN(tls->why, site_level);
+	    }
+	    continue;
+	}
+	msg_warn("%s: invalid attribute name: \"%s\"", WHERE, name);
+	INVALID_RETURN(tls->why, site_level);
+    }
+
+    FREE_RETURN;
+}
+
+/* tls_policy_lookup - look up destination TLS policy */
+
+static void tls_policy_lookup(SMTP_TLS_POLICY *tls, int *site_level,
+			              const char *site_name,
+			              const char *site_class)
+{
+
+    /*
+     * Only one lookup with [nexthop]:port, [nexthop] or nexthop:port These
+     * are never the domain part of localpart@domain, rather they are
+     * explicit nexthops from transport:nexthop, and match only the
+     * corresponding policy. Parent domain matching (below) applies only to
+     * sub-domains of the recipient domain.
+     * 
+     * XXX UNIX-domain connections query with the pathname as destination.
+     */
+    if (!valid_utf8_hostname(var_smtputf8_enable, site_name, DONT_GRIPE)) {
+	tls_policy_lookup_one(tls, site_level, site_name, site_class);
+	return;
+    }
+    do {
+	tls_policy_lookup_one(tls, site_level, site_name, site_class);
+    } while (*site_level == TLS_LEV_NOTFOUND
+	     && (site_name = strchr(site_name + 1, '.')) != 0);
+}
+
+/* load_tas - load one or more ta files */
+
+static int load_tas(TLS_DANE *dane, const char *files)
+{
+    int     ret = 0;
+    char   *save = mystrdup(files);
+    char   *buf = save;
+    char   *file;
+
+    do {
+	if ((file = mystrtok(&buf, CHARS_COMMA_SP)) != 0)
+	    ret = tls_dane_load_trustfile(dane, file);
+    } while (file && ret);
+
+    myfree(save);
+    return (ret);
+}
+
+/* set_cipher_grade - Set cipher grade and exclusions */
+
+static void set_cipher_grade(SMTP_TLS_POLICY *tls)
+{
+    const char *mand_exclude = "";
+    const char *also_exclude = "";
+
+    /*
+     * Use main.cf cipher level if no per-destination value specified. With
+     * mandatory encryption at least encrypt, and with mandatory verification
+     * at least authenticate!
+     */
+    switch (tls->level) {
+    case TLS_LEV_INVALID:
+    case TLS_LEV_NONE:
+	return;
+
+    case TLS_LEV_MAY:
+	if (tls->grade == 0)
+	    tls->grade = mystrdup(var_smtp_tls_ciph);
+	break;
+
+    case TLS_LEV_ENCRYPT:
+	if (tls->grade == 0)
+	    tls->grade = mystrdup(var_smtp_tls_mand_ciph);
+	mand_exclude = var_smtp_tls_mand_excl;
+	also_exclude = "eNULL";
+	break;
+
+    case TLS_LEV_HALF_DANE:
+    case TLS_LEV_DANE:
+    case TLS_LEV_DANE_ONLY:
+    case TLS_LEV_FPRINT:
+    case TLS_LEV_VERIFY:
+    case TLS_LEV_SECURE:
+	if (tls->grade == 0)
+	    tls->grade = mystrdup(var_smtp_tls_mand_ciph);
+	mand_exclude = var_smtp_tls_mand_excl;
+	also_exclude = "aNULL";
+	break;
+    }
+
+#define ADD_EXCLUDE(vstr, str) \
+    do { \
+	if (*(str)) \
+	    vstring_sprintf_append((vstr), "%s%s", \
+				   VSTRING_LEN(vstr) ? " " : "", (str)); \
+    } while (0)
+
+    /*
+     * The "exclude" policy table attribute overrides main.cf exclusion
+     * lists.
+     */
+    if (tls->exclusions == 0) {
+	tls->exclusions = vstring_alloc(10);
+	ADD_EXCLUDE(tls->exclusions, var_smtp_tls_excl_ciph);
+	ADD_EXCLUDE(tls->exclusions, mand_exclude);
+    }
+    ADD_EXCLUDE(tls->exclusions, also_exclude);
+}
+
+/* policy_create - create SMTP TLS policy cache object (ctable call-back) */
+
+static void *policy_create(const char *unused_key, void *context)
+{
+    SMTP_ITERATOR *iter = (SMTP_ITERATOR *) context;
+    int     site_level;
+    const char *dest = STR(iter->dest);
+    const char *host = STR(iter->host);
+
+    /*
+     * Prepare a pristine policy object.
+     */
+    SMTP_TLS_POLICY *tls = (SMTP_TLS_POLICY *) mymalloc(sizeof(*tls));
+
+    smtp_tls_policy_init(tls, dsb_create());
+    tls->conn_reuse = var_smtp_tls_conn_reuse;
+
+    /*
+     * Compute the per-site TLS enforcement level. For compatibility with the
+     * original TLS patch, this algorithm is gives equal precedence to host
+     * and next-hop policies.
+     */
+    tls->level = global_tls_level();
+    site_level = TLS_LEV_NOTFOUND;
+
+    if (tls_policy) {
+	tls_policy_lookup(tls, &site_level, dest, "next-hop destination");
+    } else if (tls_per_site) {
+	tls_site_lookup(tls, &site_level, dest, "next-hop destination");
+	if (site_level != TLS_LEV_INVALID
+	    && strcasecmp_utf8(dest, host) != 0)
+	    tls_site_lookup(tls, &site_level, host, "server hostname");
+
+	/*
+	 * Override a wild-card per-site policy with a more specific global
+	 * policy.
+	 * 
+	 * With the original TLS patch, 1) a per-site ENCRYPT could not override
+	 * a global VERIFY, and 2) a combined per-site (NONE+MAY) policy
+	 * produced inconsistent results: it changed a global VERIFY into
+	 * NONE, while producing MAY with all weaker global policy settings.
+	 * 
+	 * With the current implementation, a combined per-site (NONE+MAY)
+	 * consistently overrides global policy with NONE, and global policy
+	 * can override only a per-site MAY wildcard. That is, specific
+	 * policies consistently override wildcard policies, and
+	 * (non-wildcard) per-site policies consistently override global
+	 * policies.
+	 */
+	if (site_level == TLS_LEV_MAY && tls->level > TLS_LEV_MAY)
+	    site_level = tls->level;
+    }
+    switch (site_level) {
+    default:
+	tls->level = site_level;
+	/* FALLTHROUGH */
+    case TLS_LEV_NOTFOUND:
+	break;
+    case TLS_LEV_INVALID:
+	tls->level = site_level;
+	return ((void *) tls);
+    }
+
+    /*
+     * DANE initialization may change the security level to something else,
+     * so do this early, so that we use the right level below.  Note that
+     * "dane-only" changes to "dane" once we obtain the requisite TLSA
+     * records.
+     */
+    if (TLS_DANE_BASED(tls->level))
+	dane_init(tls, iter);
+    if (tls->level == TLS_LEV_INVALID)
+	return ((void *) tls);
+
+    /*
+     * Use main.cf protocols and SNI settings if not set in per-destination
+     * table.
+     */
+    if (tls->level > TLS_LEV_NONE && tls->protocols == 0)
+	tls->protocols =
+	    mystrdup((tls->level == TLS_LEV_MAY) ?
+		     var_smtp_tls_proto : var_smtp_tls_mand_proto);
+    if (tls->level > TLS_LEV_NONE && tls->sni == 0) {
+	if (!*var_smtp_tls_sni || valid_hostname(var_smtp_tls_sni, DONT_GRIPE))
+	    tls->sni = mystrdup(var_smtp_tls_sni);
+	else {
+	    msg_warn("\"%s = %s\" specifies an invalid hostname",
+		     VAR_LMTP_SMTP(TLS_SNI), var_smtp_tls_sni);
+	    MARK_INVALID(tls->why, &tls->level);
+	    return ((void *) tls);
+	}
+    }
+
+    /*
+     * Compute cipher grade (if set in per-destination table, else
+     * set_cipher() uses main.cf settings) and security level dependent
+     * cipher exclusion list.
+     */
+    set_cipher_grade(tls);
+
+    /*
+     * Use main.cf cert_match setting if not set in per-destination table.
+     */
+    switch (tls->level) {
+    case TLS_LEV_INVALID:
+    case TLS_LEV_NONE:
+    case TLS_LEV_MAY:
+    case TLS_LEV_ENCRYPT:
+    case TLS_LEV_HALF_DANE:
+    case TLS_LEV_DANE:
+    case TLS_LEV_DANE_ONLY:
+	break;
+    case TLS_LEV_FPRINT:
+	if (tls->dane == 0)
+	    tls->dane = tls_dane_alloc();
+	if (!TLS_DANE_HASEE(tls->dane)) {
+	    tls_dane_add_ee_digests(tls->dane, var_smtp_tls_fpt_dgst,
+				    var_smtp_tls_fpt_cmatch, CHARS_COMMA_SP);
+	    if (!TLS_DANE_HASEE(tls->dane)) {
+		msg_warn("nexthop domain %s: configured at fingerprint "
+		       "security level, but with no fingerprints to match.",
+			 dest);
+		MARK_INVALID(tls->why, &tls->level);
+		return ((void *) tls);
+	    }
+	}
+	break;
+    case TLS_LEV_VERIFY:
+    case TLS_LEV_SECURE:
+	if (tls->matchargv == 0)
+	    tls->matchargv =
+		argv_split(tls->level == TLS_LEV_VERIFY ?
+			   var_smtp_tls_vfy_cmatch : var_smtp_tls_sec_cmatch,
+			   CHARS_COMMA_SP ":");
+	if (*var_smtp_tls_tafile) {
+	    if (tls->dane == 0)
+		tls->dane = tls_dane_alloc();
+	    if (!TLS_DANE_HASTA(tls->dane)
+		&& !load_tas(tls->dane, var_smtp_tls_tafile)) {
+		MARK_INVALID(tls->why, &tls->level);
+		return ((void *) tls);
+	    }
+	}
+	break;
+    default:
+	msg_panic("unexpected TLS security level: %d", tls->level);
+    }
+
+    if (msg_verbose && tls->level != global_tls_level())
+	msg_info("%s TLS level: %s", "effective", policy_name(tls->level));
+
+    return ((void *) tls);
+}
+
+/* policy_delete - free no longer cached policy (ctable call-back) */
+
+static void policy_delete(void *item, void *unused_context)
+{
+    SMTP_TLS_POLICY *tls = (SMTP_TLS_POLICY *) item;
+
+    if (tls->protocols)
+	myfree(tls->protocols);
+    if (tls->sni)
+	myfree(tls->sni);
+    if (tls->grade)
+	myfree(tls->grade);
+    if (tls->exclusions)
+	vstring_free(tls->exclusions);
+    if (tls->matchargv)
+	argv_free(tls->matchargv);
+    if (tls->dane)
+	tls_dane_free(tls->dane);
+    dsb_free(tls->why);
+
+    myfree((void *) tls);
+}
+
+/* smtp_tls_policy_cache_query - cached lookup of TLS policy */
+
+int     smtp_tls_policy_cache_query(DSN_BUF *why, SMTP_TLS_POLICY *tls,
+				            SMTP_ITERATOR *iter)
+{
+    VSTRING *key;
+
+    /*
+     * Create an empty TLS Policy cache on the fly.
+     */
+    if (policy_cache == 0)
+	policy_cache =
+	    ctable_create(CACHE_SIZE, policy_create, policy_delete, (void *) 0);
+
+    /*
+     * Query the TLS Policy cache, with a search key that reflects our shared
+     * values that also appear in other cache and table search keys.
+     */
+    key = vstring_alloc(100);
+    smtp_key_prefix(key, ":", iter, SMTP_KEY_FLAG_CUR_NEXTHOP
+		    | SMTP_KEY_FLAG_HOSTNAME
+		    | SMTP_KEY_FLAG_PORT);
+    ctable_newcontext(policy_cache, (void *) iter);
+    *tls = *(SMTP_TLS_POLICY *) ctable_locate(policy_cache, STR(key));
+    vstring_free(key);
+
+    /*
+     * Report errors. Both error and non-error results are cached. We must
+     * therefore copy the cached DSN buffer content to the caller's buffer.
+     */
+    if (tls->level == TLS_LEV_INVALID) {
+	/* XXX Simplify this by implementing a "copy" primitive. */
+	dsb_update(why,
+		   STR(tls->why->status), STR(tls->why->action),
+		   STR(tls->why->mtype), STR(tls->why->mname),
+		   STR(tls->why->dtype), STR(tls->why->dtext),
+		   "%s", STR(tls->why->reason));
+	return (0);
+    } else {
+	return (1);
+    }
+}
+
+/* smtp_tls_policy_cache_flush - flush TLS policy cache */
+
+void    smtp_tls_policy_cache_flush(void)
+{
+    if (policy_cache != 0) {
+	ctable_free(policy_cache);
+	policy_cache = 0;
+    }
+}
+
+/* global_tls_level - parse and cache var_smtp_tls_level */
+
+static int global_tls_level(void)
+{
+    static int l = TLS_LEV_NOTFOUND;
+
+    if (l != TLS_LEV_NOTFOUND)
+	return l;
+
+    /*
+     * Compute the global TLS policy. This is the default policy level when
+     * no per-site policy exists. It also is used to override a wild-card
+     * per-site policy.
+     * 
+     * We require that the global level is valid on startup.
+     */
+    if (*var_smtp_tls_level) {
+	if ((l = tls_level_lookup(var_smtp_tls_level)) == TLS_LEV_INVALID)
+	    msg_fatal("invalid tls security level: \"%s\"", var_smtp_tls_level);
+    } else if (var_smtp_enforce_tls)
+	l = var_smtp_tls_enforce_peername ? TLS_LEV_VERIFY : TLS_LEV_ENCRYPT;
+    else
+	l = var_smtp_use_tls ? TLS_LEV_MAY : TLS_LEV_NONE;
+
+    if (msg_verbose)
+	msg_info("%s TLS level: %s", "global", policy_name(l));
+
+    return l;
+}
+
+#define NONDANE_CONFIG	0		/* Administrator's fault */
+#define NONDANE_DEST	1		/* Remote server's fault */
+#define DANE_CANTAUTH	2		/* Remote server's fault */
+
+static void PRINTFLIKE(4, 5) dane_incompat(SMTP_TLS_POLICY *tls,
+					           SMTP_ITERATOR *iter,
+					           int errtype,
+					           const char *fmt,...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    if (tls->level == TLS_LEV_DANE) {
+	tls->level = (errtype == DANE_CANTAUTH) ? TLS_LEV_ENCRYPT : TLS_LEV_MAY;
+	if (errtype == NONDANE_CONFIG)
+	    vmsg_warn(fmt, ap);
+	else if (msg_verbose)
+	    vmsg_info(fmt, ap);
+    } else {					/* dane-only */
+	if (errtype == NONDANE_CONFIG) {
+	    vmsg_warn(fmt, ap);
+	    MARK_INVALID(tls->why, &tls->level);
+	} else {
+	    tls->level = TLS_LEV_INVALID;
+	    vdsb_simple(tls->why, "4.7.5", fmt, ap);
+	}
+    }
+    va_end(ap);
+}
+
+/* dane_init - special initialization for "dane" security level */
+
+static void dane_init(SMTP_TLS_POLICY *tls, SMTP_ITERATOR *iter)
+{
+    TLS_DANE *dane;
+
+    if (!iter->port) {
+	msg_warn("%s: the \"dane\" security level is invalid for delivery via"
+		 " unix-domain sockets", STR(iter->dest));
+	MARK_INVALID(tls->why, &tls->level);
+	return;
+    }
+    if (!tls_dane_avail()) {
+	dane_incompat(tls, iter, NONDANE_CONFIG,
+		      "%s: %s configured, but no requisite library support",
+		      STR(iter->dest), policy_name(tls->level));
+	return;
+    }
+    if (!(smtp_host_lookup_mask & SMTP_HOST_FLAG_DNS)
+	|| smtp_dns_support != SMTP_DNS_DNSSEC) {
+	dane_incompat(tls, iter, NONDANE_CONFIG,
+		      "%s: %s configured with dnssec lookups disabled",
+		      STR(iter->dest), policy_name(tls->level));
+	return;
+    }
+
+    /*
+     * If we ignore MX lookup errors, we also ignore DNSSEC security problems
+     * and thus avoid any reasonable expectation that we get the right DANE
+     * key material.
+     */
+    if (smtp_mode && var_ign_mx_lookup_err) {
+	dane_incompat(tls, iter, NONDANE_CONFIG,
+		      "%s: %s configured with MX lookup errors ignored",
+		      STR(iter->dest), policy_name(tls->level));
+	return;
+    }
+
+    /*
+     * This is not optional, code in tls_dane.c assumes that the nexthop
+     * qname is already an fqdn.  If we're using these flags to go from qname
+     * to rname, the assumption is invalid.  Likewise we cannot add the qname
+     * to certificate name checks, ...
+     */
+    if (smtp_dns_res_opt & (RES_DEFNAMES | RES_DNSRCH)) {
+	dane_incompat(tls, iter, NONDANE_CONFIG,
+		      "%s: dns resolver options incompatible with %s TLS",
+		      STR(iter->dest), policy_name(tls->level));
+	return;
+    }
+
+    /*
+     * When the MX name is present and insecure, DANE may not apply, we then
+     * either fail if DANE is mandatory or use regular opportunistic TLS if
+     * the insecure MX level is "may".
+     */
+    if (iter->mx && !iter->mx->dnssec_valid
+	&& (tls->level == TLS_LEV_DANE_ONLY ||
+	    smtp_tls_insecure_mx_policy <= TLS_LEV_MAY)) {
+	dane_incompat(tls, iter, NONDANE_DEST, "non DNSSEC destination");
+	return;
+    }
+    /* When TLSA lookups fail, we defer the message */
+    if ((dane = tls_dane_resolve(iter->port, "tcp", iter->rr,
+				 var_smtp_tls_force_tlsa)) == 0) {
+	tls->level = TLS_LEV_INVALID;
+	dsb_simple(tls->why, "4.7.5", "TLSA lookup error for %s:%u",
+		   STR(iter->host), ntohs(iter->port));
+	return;
+    }
+    if (tls_dane_notfound(dane)) {
+	dane_incompat(tls, iter, NONDANE_DEST, "no TLSA records found");
+	tls_dane_free(dane);
+	return;
+    }
+
+    /*
+     * Some TLSA records found, but none usable, per
+     * 
+     * https://tools.ietf.org/html/draft-ietf-dane-srv-02#section-4
+     * 
+     * we MUST use TLS, and SHALL use full PKIX certificate checks.  The latter
+     * would be unwise for SMTP: no human present to "click ok" and risk of
+     * non-delivery in most cases exceeds risk of interception.
+     * 
+     * We also have a form of Goedel's incompleteness theorem in play: any list
+     * of public root CA certs is either incomplete or inconsistent (for any
+     * given verifier some of the CAs are surely not trustworthy).
+     */
+    if (tls_dane_unusable(dane)) {
+	dane_incompat(tls, iter, DANE_CANTAUTH, "TLSA records unusable");
+	tls_dane_free(dane);
+	return;
+    }
+
+    /*
+     * Perhaps downgrade to "encrypt" if MX is insecure.
+     */
+    if (iter->mx && !iter->mx->dnssec_valid) {
+	if (smtp_tls_insecure_mx_policy == TLS_LEV_ENCRYPT) {
+	    dane_incompat(tls, iter, DANE_CANTAUTH,
+			  "Verification not possible, MX RRset is insecure");
+	    tls_dane_free(dane);
+	    return;
+	}
+	if (tls->level != TLS_LEV_DANE
+	    || smtp_tls_insecure_mx_policy != TLS_LEV_DANE)
+	    msg_panic("wrong state for insecure MX host DANE policy");
+
+	/* For correct logging in tls_client_start() */
+	tls->level = TLS_LEV_HALF_DANE;
+    }
+
+    /*
+     * With DANE trust anchors, peername matching is not configurable.
+     */
+    if (TLS_DANE_HASTA(dane)) {
+	tls->matchargv = argv_alloc(2);
+	argv_add(tls->matchargv, dane->base_domain, ARGV_END);
+	if (iter->mx) {
+	    if (strcmp(iter->mx->qname, iter->mx->rname) == 0)
+		argv_add(tls->matchargv, iter->mx->qname, ARGV_END);
+	    else
+		argv_add(tls->matchargv, iter->mx->rname,
+			 iter->mx->qname, ARGV_END);
+	}
+    } else if (!TLS_DANE_HASEE(dane))
+	msg_panic("empty DANE match list");
+    tls->dane = dane;
+    return;
+}
+
+#endif
diff --git a/src/smtp/smtp_trouble.c b/src/smtp/smtp_trouble.c
new file mode 100644
index 0000000..60880df
--- /dev/null
+++ b/src/smtp/smtp_trouble.c
@@ -0,0 +1,476 @@
+/*++
+/* NAME
+/*	smtp_trouble 3
+/* SUMMARY
+/*	error handler policies
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	int	smtp_sess_fail(state)
+/*	SMTP_STATE *state;
+/*
+/*	int	smtp_site_fail(state, mta_name, resp, format, ...)
+/*	SMTP_STATE *state;
+/*	const char *mta_name;
+/*	SMTP_RESP *resp;
+/*	const char *format;
+/*
+/*	int	smtp_mesg_fail(state, mta_name, resp, format, ...)
+/*	SMTP_STATE *state;
+/*	const char *mta_name;
+/*	SMTP_RESP *resp;
+/*	const char *format;
+/*
+/*	void	smtp_rcpt_fail(state, recipient, mta_name, resp, format, ...)
+/*	SMTP_STATE *state;
+/*	RECIPIENT *recipient;
+/*	const char *mta_name;
+/*	SMTP_RESP *resp;
+/*	const char *format;
+/*
+/*	int	smtp_stream_except(state, exception, description)
+/*	SMTP_STATE *state;
+/*	int	exception;
+/*	const char *description;
+/* AUXILIARY FUNCTIONS
+/*	int	smtp_misc_fail(state, throttle, mta_name, resp, format, ...)
+/*	SMTP_STATE *state;
+/*	int	throttle;
+/*	const char *mta_name;
+/*	SMTP_RESP *resp;
+/*	const char *format;
+/* DESCRIPTION
+/*	This module handles all non-fatal errors that can happen while
+/*	attempting to deliver mail via SMTP, and implements the policy
+/*	of how to deal with the error. Depending on the nature of
+/*	the problem, delivery of a single message is deferred, delivery
+/*	of all messages to the same domain is deferred, or one or more
+/*	recipients are given up as non-deliverable and a bounce log is
+/*	updated. In any case, the recipient is marked as either KEEP
+/*	(try again with a backup host) or DROP (delete recipient from
+/*	delivery request).
+/*
+/*	In addition, when an unexpected response code is seen such
+/*	as 3xx where only 4xx or 5xx are expected, or any error code
+/*	that suggests a syntax error or something similar, the
+/*	protocol error flag is set so that the postmaster receives
+/*	a transcript of the session. No notification is generated for
+/*	what appear to be configuration errors - very likely, they
+/*	would suffer the same problem and just cause more trouble.
+/*
+/*	In case of a soft error, action depends on whether the error
+/*	qualifies for trying the request with other mail servers (log
+/*	an informational record only and try a backup server) or
+/*	whether this is the final server (log recipient delivery status
+/*	records and delete the recipient from the request).
+/*
+/*	smtp_sess_fail() takes a pre-formatted error report after
+/*	failure to complete some protocol handshake.  The policy is
+/*	as with smtp_site_fail().
+/*
+/*	smtp_site_fail() handles the case where the program fails to
+/*	complete the initial handshake: the server is not reachable,
+/*	is not running, does not want talk to us, or we talk to ourselves.
+/*	The \fIcode\fR gives an error status code; the \fIformat\fR
+/*	argument gives a textual description.
+/*	The policy is: soft error, non-final server: log an informational
+/*	record why the host is being skipped; soft error, final server:
+/*	defer delivery of all remaining recipients and mark the destination
+/*	as problematic; hard error: bounce all remaining recipients.
+/*	The session is marked as "do not cache".
+/*	The result is non-zero.
+/*
+/*	smtp_mesg_fail() handles the case where the smtp server
+/*	does not accept the sender address or the message data,
+/*	or when the local MTA is unable to convert the message data.
+/*	The policy is: soft error, non-final server: log an informational
+/*	record why the host is being skipped; soft error, final server:
+/*	defer delivery of all remaining recipients; hard error: bounce all
+/*	remaining recipients.
+/*	The result is non-zero.
+/*
+/*	smtp_misc_fail() provides a more detailed interface than
+/*	smtp_site_fail() and smtp_mesg_fail(), which are convenience
+/*	wrappers around smtp_misc_fail(). The throttle argument
+/*	is either SMTP_THROTTLE or SMTP_NOTHROTTLE; it is used only
+/*	in the "soft error, final server" policy, and determines
+/*	whether a destination will be marked as problematic.
+/*
+/*	smtp_rcpt_fail() handles the case where a recipient is not
+/*	accepted by the server for reasons other than that the server
+/*	recipient limit is reached.
+/*	The policy is: soft error, non-final server: log an informational
+/*	record why the recipient is being skipped; soft error, final server:
+/*	defer delivery of this recipient; hard error: bounce this
+/*	recipient.
+/*
+/*	smtp_stream_except() handles the exceptions generated by
+/*	the smtp_stream(3) module (i.e. timeouts and I/O errors).
+/*	The \fIexception\fR argument specifies the type of problem.
+/*	The \fIdescription\fR argument describes at what stage of
+/*	the SMTP dialog the problem happened.
+/*	The policy is: non-final server: log an informational record
+/*	with the reason why the host is being skipped; final server:
+/*	defer delivery of all remaining recipients.
+/*	Retry plaintext delivery after TLS post-handshake session
+/*	failure, provided that at least one recipient was not
+/*	deferred or rejected during the TLS phase, and that global
+/*	preconditions for plaintext fallback are met.
+/*	The session is marked as "do not cache".
+/*	The result is non-zero.
+/*
+/*	Arguments:
+/* .IP state
+/*	SMTP client state per delivery request.
+/* .IP resp
+/*	Server response including reply code and text.
+/* .IP recipient
+/*	Undeliverable recipient address information.
+/* .IP format
+/*	Human-readable description of why mail is not deliverable.
+/* DIAGNOSTICS
+/*	Panic: unknown exception code.
+/* SEE ALSO
+/*	smtp_proto(3) smtp high-level protocol
+/*	smtp_stream(3) smtp low-level protocol
+/*	defer(3) basic message defer interface
+/*	bounce(3) basic message bounce interface
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <stdlib.h>			/* 44BSD stdarg.h uses abort() */
+#include <stdarg.h>
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <smtp_stream.h>
+#include <deliver_request.h>
+#include <deliver_completed.h>
+#include <bounce.h>
+#include <defer.h>
+#include <mail_error.h>
+#include <dsn_buf.h>
+#include <dsn.h>
+#include <mail_params.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+/* smtp_check_code - check response code */
+
+static void smtp_check_code(SMTP_SESSION *session, int code)
+{
+
+    /*
+     * The intention of this code is to alert the postmaster when the local
+     * Postfix SMTP client screws up, protocol wise. RFC 821 says that x0z
+     * replies "refer to syntax errors, syntactically correct commands that
+     * don't fit any functional category, and unimplemented or superfluous
+     * commands". Unfortunately, this also triggers postmaster notices when
+     * remote servers screw up, protocol wise. This is becoming a common
+     * problem now that response codes are configured manually as part of
+     * anti-UCE systems, by people who aren't aware of RFC details.
+     * 
+     * Fix 20190621: don't cache an SMTP session after an SMTP protocol error.
+     * The protocol may be in a bad state. Disable caching here so that the
+     * protocol engine will send QUIT.
+     */
+    if (code < 400 || code > 599
+	|| code == 555			/* RFC 1869, section 6.1. */
+	|| (code >= 500 && code < 510)) {
+	session->error_mask |= MAIL_ERROR_PROTOCOL;
+	DONT_CACHE_THIS_SESSION;
+    }
+}
+
+/* smtp_bulk_fail - skip, defer or bounce recipients, maybe throttle queue */
+
+static int smtp_bulk_fail(SMTP_STATE *state, int throttle_queue)
+{
+    DELIVER_REQUEST *request = state->request;
+    SMTP_SESSION *session = state->session;
+    DSN_BUF *why = state->why;
+    RECIPIENT *rcpt;
+    int     status;
+    int     aggregate_status;
+    int     soft_error = (STR(why->status)[0] == '4');
+    int     soft_bounce_error = (STR(why->status)[0] == '5' && var_soft_bounce);
+    int     nrcpt;
+
+    /*
+     * Don't defer the recipients just yet when this error qualifies them for
+     * delivery to a backup server. Just log something informative to show
+     * why we're skipping this host.
+     */
+    if ((soft_error || soft_bounce_error)
+	&& (state->misc_flags & SMTP_MISC_FLAG_FINAL_SERVER) == 0) {
+	msg_info("%s: %s", request->queue_id, STR(why->reason));
+	for (nrcpt = 0; nrcpt < SMTP_RCPT_LEFT(state); nrcpt++) {
+	    rcpt = request->rcpt_list.info + nrcpt;
+	    if (SMTP_RCPT_ISMARKED(rcpt))
+		continue;
+	    SMTP_RCPT_KEEP(state, rcpt);
+	}
+    }
+
+    /*
+     * Defer or bounce all the remaining recipients, and delete them from the
+     * delivery request. If a bounce fails, defer instead and do not qualify
+     * the recipient for delivery to a backup server.
+     */
+    else {
+
+	/*
+	 * If we are still in the connection set-up phase, update the set-up
+	 * completion time here, otherwise the time spent in set-up latency
+	 * will be attributed as message transfer latency.
+	 * 
+	 * All remaining recipients have failed at this point, so we update the
+	 * delivery completion time stamp so that multiple recipient status
+	 * records show the same delay values.
+	 */
+	if (request->msg_stats.conn_setup_done.tv_sec == 0) {
+	    GETTIMEOFDAY(&request->msg_stats.conn_setup_done);
+	    request->msg_stats.deliver_done =
+		request->msg_stats.conn_setup_done;
+	} else
+	    GETTIMEOFDAY(&request->msg_stats.deliver_done);
+
+	(void) DSN_FROM_DSN_BUF(why);
+	aggregate_status = 0;
+	for (nrcpt = 0; nrcpt < SMTP_RCPT_LEFT(state); nrcpt++) {
+	    rcpt = request->rcpt_list.info + nrcpt;
+	    if (SMTP_RCPT_ISMARKED(rcpt))
+		continue;
+	    status = (soft_error ? defer_append : bounce_append)
+		(DEL_REQ_TRACE_FLAGS(request->flags), request->queue_id,
+		 &request->msg_stats, rcpt,
+		 session ? session->namaddrport : "none", &why->dsn);
+	    if (status == 0)
+		deliver_completed(state->src, rcpt->offset);
+	    SMTP_RCPT_DROP(state, rcpt);
+	    aggregate_status |= status;
+	}
+	state->status |= aggregate_status;
+	if ((state->misc_flags & SMTP_MISC_FLAG_COMPLETE_SESSION) == 0
+	    && throttle_queue && aggregate_status
+	    && request->hop_status == 0)
+	    request->hop_status = DSN_COPY(&why->dsn);
+    }
+
+    /*
+     * Don't cache this session. We can't talk to this server.
+     */
+    if (throttle_queue && session)
+	DONT_CACHE_THROTTLED_SESSION;
+
+    return (-1);
+}
+
+/* smtp_sess_fail - skip site, defer or bounce all recipients */
+
+int     smtp_sess_fail(SMTP_STATE *state)
+{
+
+    /*
+     * We can't avoid copying copying lots of strings into VSTRING buffers,
+     * because this error information is collected by a routine that
+     * terminates BEFORE the error is reported.
+     */
+    return (smtp_bulk_fail(state, SMTP_THROTTLE));
+}
+
+/* vsmtp_fill_dsn - fill in temporary DSN structure */
+
+static void vsmtp_fill_dsn(SMTP_STATE *state, const char *mta_name,
+			           const char *status, const char *reply,
+			           const char *format, va_list ap)
+{
+    DSN_BUF *why = state->why;
+
+    /*
+     * We could avoid copying lots of strings into VSTRING buffers, because
+     * this error information is given to us by a routine that terminates
+     * AFTER the error is reported. However, this results in ugly kludges
+     * when informal text needs to be formatted. So we maintain consistency
+     * with other error reporting in the SMTP client even if we waste a few
+     * cycles.
+     * 
+     * Fix 20190621: don't cache an SMTP session after an SMTP protocol error.
+     * The protocol may be in a bad state. Disable caching here so that the
+     * protocol engine will send QUIT.
+     */
+    VSTRING_RESET(why->reason);
+    if (mta_name && status && status[0] != '4' && status[0] != '5') {
+	SMTP_SESSION *session = state->session;
+
+	session->error_mask |= MAIL_ERROR_PROTOCOL;
+	DONT_CACHE_THIS_SESSION;
+	vstring_strcpy(why->reason, "Protocol error: ");
+	status = "5.5.0";
+    }
+    vstring_vsprintf_append(why->reason, format, ap);
+    dsb_formal(why, status, DSB_DEF_ACTION,
+	       mta_name ? DSB_MTYPE_DNS : DSB_MTYPE_NONE, mta_name,
+	       reply ? DSB_DTYPE_SMTP : DSB_DTYPE_NONE, reply);
+}
+
+/* smtp_misc_fail - maybe throttle queue; skip/defer/bounce all recipients */
+
+int     smtp_misc_fail(SMTP_STATE *state, int throttle, const char *mta_name,
+		               SMTP_RESP *resp, const char *format,...)
+{
+    va_list ap;
+
+    /*
+     * Initialize.
+     */
+    va_start(ap, format);
+    vsmtp_fill_dsn(state, mta_name, resp->dsn, resp->str, format, ap);
+    va_end(ap);
+
+    if (state->session && mta_name)
+	smtp_check_code(state->session, resp->code);
+
+    /*
+     * Skip, defer or bounce recipients, and throttle this queue.
+     */
+    return (smtp_bulk_fail(state, throttle));
+}
+
+/* smtp_rcpt_fail - skip, defer, or bounce recipient */
+
+void    smtp_rcpt_fail(SMTP_STATE *state, RECIPIENT *rcpt, const char *mta_name,
+		               SMTP_RESP *resp, const char *format,...)
+{
+    DELIVER_REQUEST *request = state->request;
+    SMTP_SESSION *session = state->session;
+    DSN_BUF *why = state->why;
+    int     status;
+    int     soft_error;
+    int     soft_bounce_error;
+    va_list ap;
+
+    /*
+     * Sanity check.
+     */
+    if (SMTP_RCPT_ISMARKED(rcpt))
+	msg_panic("smtp_rcpt_fail: recipient <%s> is marked", rcpt->address);
+
+    /*
+     * Initialize.
+     */
+    va_start(ap, format);
+    vsmtp_fill_dsn(state, mta_name, resp->dsn, resp->str, format, ap);
+    va_end(ap);
+    soft_error = STR(why->status)[0] == '4';
+    soft_bounce_error = (STR(why->status)[0] == '5' && var_soft_bounce);
+
+    if (state->session && mta_name)
+	smtp_check_code(state->session, resp->code);
+
+    /*
+     * Don't defer this recipient record just yet when this error qualifies
+     * for trying other mail servers. Just log something informative to show
+     * why we're skipping this recipient now.
+     */
+    if ((soft_error || soft_bounce_error)
+	&& (state->misc_flags & SMTP_MISC_FLAG_FINAL_SERVER) == 0) {
+	msg_info("%s: %s", request->queue_id, STR(why->reason));
+	SMTP_RCPT_KEEP(state, rcpt);
+    }
+
+    /*
+     * Defer or bounce this recipient, and delete from the delivery request.
+     * If the bounce fails, defer instead and do not qualify the recipient
+     * for delivery to a backup server.
+     * 
+     * Note: we may still make an SMTP connection to deliver other recipients
+     * that did qualify for delivery to a backup server.
+     */
+    else {
+	(void) DSN_FROM_DSN_BUF(state->why);
+	status = (soft_error ? defer_append : bounce_append)
+	    (DEL_REQ_TRACE_FLAGS(request->flags), request->queue_id,
+	     &request->msg_stats, rcpt,
+	     session ? session->namaddrport : "none", &why->dsn);
+	if (status == 0)
+	    deliver_completed(state->src, rcpt->offset);
+	SMTP_RCPT_DROP(state, rcpt);
+	state->status |= status;
+    }
+}
+
+/* smtp_stream_except - defer domain after I/O problem */
+
+int     smtp_stream_except(SMTP_STATE *state, int code, const char *description)
+{
+    SMTP_SESSION *session = state->session;
+    DSN_BUF *why = state->why;
+
+    /*
+     * Sanity check.
+     */
+    if (session == 0)
+	msg_panic("smtp_stream_except: no session");
+
+    /*
+     * Initialize.
+     */
+    switch (code) {
+    default:
+	msg_panic("smtp_stream_except: unknown exception %d", code);
+    case SMTP_ERR_EOF:
+	dsb_simple(why, "4.4.2", "lost connection with %s while %s",
+		   session->namaddr, description);
+#ifdef USE_TLS
+	if (PLAINTEXT_FALLBACK_OK_AFTER_TLS_SESSION_FAILURE)
+	    RETRY_AS_PLAINTEXT;
+#endif
+	break;
+    case SMTP_ERR_TIME:
+	dsb_simple(why, "4.4.2", "conversation with %s timed out while %s",
+		   session->namaddr, description);
+#ifdef USE_TLS
+	if (PLAINTEXT_FALLBACK_OK_AFTER_TLS_SESSION_FAILURE)
+	    RETRY_AS_PLAINTEXT;
+#endif
+	break;
+    case SMTP_ERR_DATA:
+	session->error_mask |= MAIL_ERROR_DATA;
+	dsb_simple(why, "4.3.0", "local data error while talking to %s",
+		   session->namaddr);
+    }
+
+    /*
+     * The smtp_bulk_fail() call below will not throttle the destination when
+     * falling back to plaintext, because RETRY_AS_PLAINTEXT clears the
+     * FINAL_SERVER flag.
+     */
+    return (smtp_bulk_fail(state, SMTP_THROTTLE));
+}
diff --git a/src/smtp/smtp_unalias.c b/src/smtp/smtp_unalias.c
new file mode 100644
index 0000000..1c4d34d
--- /dev/null
+++ b/src/smtp/smtp_unalias.c
@@ -0,0 +1,142 @@
+/*++
+/* NAME
+/*	smtp_unalias 3
+/* SUMMARY
+/*	replace host/domain alias by official name
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	const char *smtp_unalias_name(name)
+/*	const char *name;
+/*
+/*	VSTRING	*smtp_unalias_addr(result, addr)
+/*	VSTRING *result;
+/*	const char *addr;
+/* DESCRIPTION
+/*	smtp_unalias_name() looks up A or MX records for the specified
+/*	name and returns the official name provided in the reply. When
+/*	no A or MX record is found, the result is a copy of the input.
+/*	In order to improve performance, smtp_unalias_name() remembers
+/*	results in a private cache, so a name is looked up only once.
+/*
+/*	smtp_unalias_addr() returns the input address, which is in
+/*	RFC 821 quoted form, after replacing the domain part by the
+/*	official name as found by smtp_unalias_name(). When the input
+/*	contains no domain part, the result is a copy of the input.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <netdb.h>
+#include <string.h>
+
+/* Utility library. */
+
+#include <htable.h>
+#include <vstring.h>
+#include <msg.h>
+
+/* DNS library. */
+
+#include <dns.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+
+static int smtp_unalias_flags;
+
+/* smtp_unalias_name - look up the official host or domain name. */
+
+const char *smtp_unalias_name(const char *name)
+{
+    static HTABLE *cache;
+    VSTRING *fqdn;
+    char   *result;
+
+    if (*name == '[')
+	return (name);
+
+    /*
+     * Initialize the cache on the fly. The smtp client is designed to exit
+     * after servicing a limited number of requests, so there is no need to
+     * prevent the cache from growing too large, or to expire old entries.
+     */
+    if (cache == 0)
+	cache = htable_create(10);
+
+    /*
+     * Look up the fqdn. If none is found use the query name instead, so that
+     * we won't lose time looking up the same bad name again.
+     */
+    if ((result = htable_find(cache, name)) == 0) {
+	fqdn = vstring_alloc(10);
+	if (dns_lookup_l(name, smtp_unalias_flags, (DNS_RR **) 0, fqdn,
+			     (VSTRING *) 0, DNS_REQ_FLAG_NONE, T_MX, T_A,
+#ifdef HAS_IPV6
+			     T_AAAA,
+#endif
+			     0) != DNS_OK)
+	    vstring_strcpy(fqdn, name);
+	htable_enter(cache, name, result = vstring_export(fqdn));
+    }
+    return (result);
+}
+
+/* smtp_unalias_addr - rewrite aliases in domain part of address */
+
+VSTRING *smtp_unalias_addr(VSTRING *result, const char *addr)
+{
+    char   *at;
+    const char *fqdn;
+
+    if ((at = strrchr(addr, '@')) == 0 || at[1] == 0) {
+	vstring_strcpy(result, addr);
+    } else {
+	fqdn = smtp_unalias_name(at + 1);
+	vstring_strncpy(result, addr, at - addr + 1);
+	vstring_strcat(result, fqdn);
+    }
+    return (result);
+}
+
+#ifdef TEST
+
+ /*
+  * Test program - read address from stdin, print result on stdout.
+  */
+
+#include <vstring_vstream.h>
+
+int     main(int unused_argc, char **unused_argv)
+{
+    VSTRING *addr = vstring_alloc(10);
+    VSTRING *result = vstring_alloc(10);
+
+    smtp_unalias_flags |= RES_DEBUG;
+
+    while (vstring_fgets_nonl(addr, VSTREAM_IN)) {
+	smtp_unalias_addr(result, vstring_str(addr));
+	vstream_printf("%s -> %s\n", vstring_str(addr), vstring_str(result));
+	vstream_fflush(VSTREAM_OUT);
+    }
+    vstring_free(addr);
+    vstring_free(result);
+    return (0);
+}
+
+#endif
diff --git a/src/smtp/tls_policy.in b/src/smtp/tls_policy.in
new file mode 100644
index 0000000..95c295b
--- /dev/null
+++ b/src/smtp/tls_policy.in
@@ -0,0 +1,64 @@
+-	-	-
+-	-	may
+-	-	must_nopeermatch
+-	-	must
+-	none	-
+-	none	may
+-	none	must_nopeermatch
+-	none	must
+-	may	-
+-	may	may
+-	may	must_nopeermatch
+-	may	must
+-	must_nopeermatch	-
+-	must_nopeermatch	may
+-	must_nopeermatch	must_nopeermatch
+-	must_nopeermatch	must
+-	must	-
+-	must	may
+-	must	must_nopeermatch
+-	must	must
+
+none	none	-
+none	none	may
+none	none	must_nopeermatch
+none	none	must
+none	may	-
+none	may	may
+none	may	must_nopeermatch
+none	may	must
+none	must_nopeermatch	-
+none	must_nopeermatch	may
+none	must_nopeermatch	must_nopeermatch
+none	must_nopeermatch	must
+none	must	-
+none	must	may
+none	must	must_nopeermatch
+none	must	must
+
+may	may	-
+may	may	may
+may	may	must_nopeermatch
+may	may	must
+may	must_nopeermatch	-
+may	must_nopeermatch	may
+may	must_nopeermatch	must_nopeermatch
+may	must_nopeermatch	must
+may	must	-
+may	must	may
+may	must	must_nopeermatch
+may	must	must
+
+must_nopeermatch	must_nopeermatch	-
+must_nopeermatch	must_nopeermatch	may
+must_nopeermatch	must_nopeermatch	must_nopeermatch
+must_nopeermatch	must_nopeermatch	must
+must_nopeermatch	must	-
+must_nopeermatch	must	may
+must_nopeermatch	must	must_nopeermatch
+must_nopeermatch	must	must
+
+must	must	-
+must	must	may
+must	must	must_nopeermatch
+must	must	must
diff --git a/src/smtp/tls_policy.ref b/src/smtp/tls_policy.ref
new file mode 100644
index 0000000..5b9f187
--- /dev/null
+++ b/src/smtp/tls_policy.ref
@@ -0,0 +1,65 @@
+host                 dest                 global               result
+-                    -                    -                    none
+-                    -                    may                  may
+-                    -                    must_nopeermatch     must_nopeermatch
+-                    -                    must                 must
+-                    none                 -                    none
+-                    none                 may                  none
+-                    none                 must_nopeermatch     none
+-                    none                 must                 none
+-                    may                  -                    may
+-                    may                  may                  may
+-                    may                  must_nopeermatch     must_nopeermatch
+-                    may                  must                 must
+-                    must_nopeermatch     -                    must_nopeermatch
+-                    must_nopeermatch     may                  must_nopeermatch
+-                    must_nopeermatch     must_nopeermatch     must_nopeermatch
+-                    must_nopeermatch     must                 must_nopeermatch
+-                    must                 -                    must
+-                    must                 may                  must
+-                    must                 must_nopeermatch     must
+-                    must                 must                 must
+
+none                 none                 -                    none
+none                 none                 may                  none
+none                 none                 must_nopeermatch     none
+none                 none                 must                 none
+none                 may                  -                    none
+none                 may                  may                  none
+none                 may                  must_nopeermatch     none
+none                 may                  must                 none
+none                 must_nopeermatch     -                    must_nopeermatch
+none                 must_nopeermatch     may                  must_nopeermatch
+none                 must_nopeermatch     must_nopeermatch     must_nopeermatch
+none                 must_nopeermatch     must                 must_nopeermatch
+none                 must                 -                    must
+none                 must                 may                  must
+none                 must                 must_nopeermatch     must
+none                 must                 must                 must
+
+may                  may                  -                    may
+may                  may                  may                  may
+may                  may                  must_nopeermatch     must_nopeermatch
+may                  may                  must                 must
+may                  must_nopeermatch     -                    must_nopeermatch
+may                  must_nopeermatch     may                  must_nopeermatch
+may                  must_nopeermatch     must_nopeermatch     must_nopeermatch
+may                  must_nopeermatch     must                 must_nopeermatch
+may                  must                 -                    must
+may                  must                 may                  must
+may                  must                 must_nopeermatch     must
+may                  must                 must                 must
+
+must_nopeermatch     must_nopeermatch     -                    must_nopeermatch
+must_nopeermatch     must_nopeermatch     may                  must_nopeermatch
+must_nopeermatch     must_nopeermatch     must_nopeermatch     must_nopeermatch
+must_nopeermatch     must_nopeermatch     must                 must_nopeermatch
+must_nopeermatch     must                 -                    must
+must_nopeermatch     must                 may                  must
+must_nopeermatch     must                 must_nopeermatch     must
+must_nopeermatch     must                 must                 must
+
+must                 must                 -                    must
+must                 must                 may                  must
+must                 must                 must_nopeermatch     must
+must                 must                 must                 must