Adding upstream version 3.4.23.upstream/3.4.23upstream

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

1 files changed, 1430 insertions, 0 deletions

diff --git a/src/smtp/smtp.c b/src/smtp/smtp.c
new file mode 100644
index 0000000..db17578
--- /dev/null
+++ b/src/smtp/smtp.c
@@ -0,0 +1,1430 @@
+/*++
+/* NAME
+/*	smtp 8
+/* SUMMARY
+/*	Postfix SMTP+LMTP client
+/* SYNOPSIS
+/*	\fBsmtp\fR [generic Postfix daemon options]
+/* 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
+/*	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
+/*	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].
+/* .PP
+/* SECURITY
+/* .ad
+/* .fi
+/*	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 caching 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 3.4.19 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
+/*	Introduced with Postfix 3.4.6, 3.3.5, 3.2.10, and 3.1.13:
+/* .IP "\fBtls_fast_shutdown_enable (yes)\fR"
+/*	A workaround for implementations that hang Postfix while shuting
+/*	down a TLS session, until Postfix times out.
+/* 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>
+
+/* Global library. */
+
+#include <deliver_request.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 */
+
+#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;
+
+/* 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);
+
+    /*
+     * 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 **argv)
+{
+    DELIVER_REQUEST *request;
+    int     status;
+
+    /*
+     * Sanity check. This service takes no command-line arguments.
+     */
+    if (argv[0])
+	msg_fatal("unexpected command-line argument: %s", argv[0]);
+
+    /*
+     * 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 **unused_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();
+}
+
+/* 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
+	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);
+}