Adding upstream version 3.8.5.upstream/3.8.5

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

1 files changed, 1047 insertions, 0 deletions

diff --git a/src/anvil/anvil.c b/src/anvil/anvil.c
new file mode 100644
index 0000000..884be28
--- /dev/null
+++ b/src/anvil/anvil.c
@@ -0,0 +1,1047 @@
+/*++
+/* NAME
+/*	anvil 8
+/* SUMMARY
+/*	Postfix session count and request rate control
+/* SYNOPSIS
+/*	\fBanvil\fR [generic Postfix daemon options]
+/* DESCRIPTION
+/*	The Postfix \fBanvil\fR(8) server maintains statistics about
+/*	client connection counts or client request rates. This
+/*	information can be used to defend against clients that
+/*	hammer a server with either too many simultaneous sessions,
+/*	or with too many successive requests within a configurable
+/*	time interval.  This server is designed to run under control
+/*	by the Postfix \fBmaster\fR(8) server.
+/*
+/*	In the following text, \fBident\fR specifies a (service,
+/*	client) combination. The exact syntax of that information
+/*	is application-dependent; the \fBanvil\fR(8) server does
+/*	not care.
+/* CONNECTION COUNT/RATE CONTROL
+/* .ad
+/* .fi
+/*	To register a new connection send the following request to
+/*	the \fBanvil\fR(8) server:
+/*
+/* .nf
+/*	    \fBrequest=connect\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server answers with the number of
+/*	simultaneous connections and the number of connections per
+/*	unit time for the (service, client) combination specified
+/*	with \fBident\fR:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/*	    \fBcount=\fInumber\fR
+/*	    \fBrate=\fInumber\fR
+/* .fi
+/*
+/*	To register a disconnect event send the following request
+/*	to the \fBanvil\fR(8) server:
+/*
+/* .nf
+/*	    \fBrequest=disconnect\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server replies with:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/* .fi
+/* MESSAGE RATE CONTROL
+/* .ad
+/* .fi
+/*	To register a message delivery request send the following
+/*	request to the \fBanvil\fR(8) server:
+/*
+/* .nf
+/*	    \fBrequest=message\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server answers with the number of message
+/*	delivery requests per unit time for the (service, client)
+/*	combination specified with \fBident\fR:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/*	    \fBrate=\fInumber\fR
+/* .fi
+/* RECIPIENT RATE CONTROL
+/* .ad
+/* .fi
+/*	To register a recipient request send the following request
+/*	to the \fBanvil\fR(8) server:
+/*
+/* .nf
+/*	    \fBrequest=recipient\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server answers with the number of recipient
+/*	addresses per unit time for the (service, client) combination
+/*	specified with \fBident\fR:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/*	    \fBrate=\fInumber\fR
+/* .fi
+/* TLS SESSION NEGOTIATION RATE CONTROL
+/* .ad
+/* .fi
+/*	The features described in this section are available with
+/*	Postfix 2.3 and later.
+/*
+/*	To register a request for a new (i.e. not cached) TLS session
+/*	send the following request to the \fBanvil\fR(8) server:
+/*
+/* .nf
+/*	    \fBrequest=newtls\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server answers with the number of new
+/*	TLS session requests per unit time for the (service, client)
+/*	combination specified with \fBident\fR:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/*	    \fBrate=\fInumber\fR
+/* .fi
+/*
+/*	To retrieve new TLS session request rate information without
+/*	updating the counter information, send:
+/*
+/* .nf
+/*	    \fBrequest=newtls_report\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server answers with the number of new
+/*	TLS session requests per unit time for the (service, client)
+/*	combination specified with \fBident\fR:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/*	    \fBrate=\fInumber\fR
+/* .fi
+/* AUTH RATE CONTROL
+/* .ad
+/* .fi
+/*	To register an AUTH request send the following request
+/*	to the \fBanvil\fR(8) server:
+/*
+/* .nf
+/*	    \fBrequest=auth\fR
+/*	    \fBident=\fIstring\fR
+/* .fi
+/*
+/*	The \fBanvil\fR(8) server answers with the number of auth
+/*	requests per unit time for the (service, client) combination
+/*	specified with \fBident\fR:
+/*
+/* .nf
+/*	    \fBstatus=0\fR
+/*	    \fBrate=\fInumber\fR
+/* .fi
+/* SECURITY
+/* .ad
+/* .fi
+/*	The \fBanvil\fR(8) server does not talk to the network or to local
+/*	users, and can run chrooted at fixed low privilege.
+/*
+/*	The \fBanvil\fR(8) server maintains an in-memory table with
+/*	information about recent clients requests.  No persistent
+/*	state is kept because standard system library routines are
+/*	not sufficiently robust for update-intensive applications.
+/*
+/*	Although the in-memory state is kept only temporarily, this
+/*	may require a lot of memory on systems that handle connections
+/*	from many remote clients.  To reduce memory usage, reduce
+/*	the time unit over which state is kept.
+/* DIAGNOSTICS
+/*	Problems and transactions are logged to \fBsyslogd\fR(8)
+/*	or \fBpostlogd\fR(8).
+/*
+/*	Upon exit, and every \fBanvil_status_update_time\fR
+/*	seconds, the server logs the maximal count and rate values measured,
+/*	together with (service, client) information and the time of day
+/*	associated with those events.
+/*	In order to avoid unnecessary overhead, no measurements
+/*	are done for activity that isn't concurrency limited or
+/*	rate limited.
+/* BUGS
+/*	Systems behind network address translating routers or proxies
+/*	appear to have the same client address and can run into connection
+/*	count and/or rate limits falsely.
+/*
+/*	In this preliminary implementation, a count (or rate) limited server
+/*	process can have only one remote client at a time. If a
+/*	server process reports
+/*	multiple simultaneous clients, state is kept only for the last
+/*	reported client.
+/*
+/*	The \fBanvil\fR(8) server automatically discards client
+/*	request information after it expires.  To prevent the
+/*	\fBanvil\fR(8) server from discarding client request rate
+/*	information too early or too late, a rate limited service
+/*	should always register connect/disconnect events even when
+/*	it does not explicitly limit them.
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/*	On low-traffic mail systems, changes to \fBmain.cf\fR are
+/*	picked up automatically as \fBanvil\fR(8) processes run for
+/*	only a limited amount of time. On other mail systems, 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.
+/* .IP "\fBanvil_rate_time_unit (60s)\fR"
+/*	The time unit over which client connection rates and other rates
+/*	are calculated.
+/* .IP "\fBanvil_status_update_time (600s)\fR"
+/*	How frequently the \fBanvil\fR(8) connection and rate limiting server
+/*	logs peak usage information.
+/* .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 "\fBipc_timeout (3600s)\fR"
+/*	The time limit for sending or receiving information over an internal
+/*	communication channel.
+/* .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 "\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 in Postfix 3.3 and later:
+/* .IP "\fBservice_name (read-only)\fR"
+/*	The master.cf service name of a Postfix daemon process.
+/* SEE ALSO
+/*	smtpd(8), Postfix SMTP server
+/*	postconf(5), configuration parameters
+/*	master(5), generic daemon options
+/* README FILES
+/* .ad
+/* .fi
+/*	Use "\fBpostconf readme_directory\fR" or
+/*	"\fBpostconf html_directory\fR" to locate this information.
+/* .na
+/* .nf
+/*	TUNING_README, performance tuning
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* HISTORY
+/* .ad
+/* .fi
+/*	The anvil service is available in Postfix 2.2 and later.
+/* 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/time.h>
+#include <limits.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <htable.h>
+#include <stringops.h>
+#include <events.h>
+
+/* Global library. */
+
+#include <mail_conf.h>
+#include <mail_params.h>
+#include <mail_version.h>
+#include <mail_proto.h>
+#include <anvil_clnt.h>
+
+/* Server skeleton. */
+
+#include <mail_server.h>
+
+/* Application-specific. */
+
+ /*
+  * Configuration parameters.
+  */
+int     var_anvil_time_unit;
+int     var_anvil_stat_time;
+
+ /*
+  * Global dynamic state.
+  */
+static HTABLE *anvil_remote_map;	/* indexed by service+ remote client */
+
+ /*
+  * Remote connection state, one instance for each (service, client) pair.
+  */
+typedef struct {
+    char   *ident;			/* lookup key */
+    int     count;			/* connection count */
+    int     rate;			/* connection rate */
+    int     mail;			/* message rate */
+    int     rcpt;			/* recipient rate */
+    int     ntls;			/* new TLS session rate */
+    int     auth;			/* AUTH request rate */
+    time_t  start;			/* time of first rate sample */
+} ANVIL_REMOTE;
+
+ /*
+  * Local server state, one instance per anvil client connection. This allows
+  * us to clean up remote connection state when a local server goes away
+  * without cleaning up.
+  */
+typedef struct {
+    ANVIL_REMOTE *anvil_remote;		/* XXX should be list */
+} ANVIL_LOCAL;
+
+ /*
+  * The following operations are implemented as macros with recognizable
+  * names so that we don't lose sight of what the code is trying to do.
+  * 
+  * Related operations are defined side by side so that the code implementing
+  * them isn't pages apart.
+  */
+
+/* Create new (service, client) state. */
+
+#define ANVIL_REMOTE_FIRST_CONN(remote, id) \
+    do { \
+	(remote)->ident = mystrdup(id); \
+	(remote)->count = 1; \
+	(remote)->rate = 1; \
+	(remote)->mail = 0; \
+	(remote)->rcpt = 0; \
+	(remote)->ntls = 0; \
+	(remote)->auth = 0; \
+	(remote)->start = event_time(); \
+    } while(0)
+
+/* Destroy unused (service, client) state. */
+
+#define ANVIL_REMOTE_FREE(remote) \
+    do { \
+	myfree((remote)->ident); \
+	myfree((void *) (remote)); \
+    } while(0)
+
+/* Reset or update rate information for existing (service, client) state. */
+
+#define ANVIL_REMOTE_RSET_RATE(remote, _start) \
+    do { \
+	(remote)->rate = 0; \
+	(remote)->mail = 0; \
+	(remote)->rcpt = 0; \
+	(remote)->ntls = 0; \
+	(remote)->auth = 0; \
+	(remote)->start = _start; \
+    } while(0)
+
+#define ANVIL_REMOTE_INCR_RATE(remote, _what) \
+    do { \
+	time_t _now = event_time(); \
+	if ((remote)->start + var_anvil_time_unit < _now) \
+	    ANVIL_REMOTE_RSET_RATE((remote), _now); \
+	if ((remote)->_what < INT_MAX) \
+            (remote)->_what += 1; \
+    } while(0)
+
+/* Update existing (service, client) state. */
+
+#define ANVIL_REMOTE_NEXT_CONN(remote) \
+    do { \
+	ANVIL_REMOTE_INCR_RATE((remote), rate); \
+	if ((remote)->count == 0) \
+	    event_cancel_timer(anvil_remote_expire, (void *) remote); \
+	(remote)->count++; \
+    } while(0)
+
+#define ANVIL_REMOTE_INCR_MAIL(remote)	ANVIL_REMOTE_INCR_RATE((remote), mail)
+
+#define ANVIL_REMOTE_INCR_RCPT(remote)	ANVIL_REMOTE_INCR_RATE((remote), rcpt)
+
+#define ANVIL_REMOTE_INCR_NTLS(remote)	ANVIL_REMOTE_INCR_RATE((remote), ntls)
+
+#define ANVIL_REMOTE_INCR_AUTH(remote)	ANVIL_REMOTE_INCR_RATE((remote), auth)
+
+/* Drop connection from (service, client) state. */
+
+#define ANVIL_REMOTE_DROP_ONE(remote) \
+    do { \
+	if ((remote) && (remote)->count > 0) { \
+	    if (--(remote)->count == 0) \
+		event_request_timer(anvil_remote_expire, (void *) remote, \
+			var_anvil_time_unit); \
+	} \
+    } while(0)
+
+/* Create local server state. */
+
+#define ANVIL_LOCAL_INIT(local) \
+    do { \
+	(local)->anvil_remote = 0; \
+    } while(0)
+
+/* Add remote connection to local server. */
+
+#define ANVIL_LOCAL_ADD_ONE(local, remote) \
+    do { \
+	/* XXX allow multiple remote clients per local server. */ \
+	if ((local)->anvil_remote) \
+	    ANVIL_REMOTE_DROP_ONE((local)->anvil_remote); \
+	(local)->anvil_remote = (remote); \
+    } while(0)
+
+/* Test if this remote connection is listed for this local server. */
+
+#define ANVIL_LOCAL_REMOTE_LINKED(local, remote) \
+    ((local)->anvil_remote == (remote))
+
+/* Drop specific remote connection from local server. */
+
+#define ANVIL_LOCAL_DROP_ONE(local, remote) \
+    do { \
+	/* XXX allow multiple remote clients per local server. */ \
+	if ((local)->anvil_remote == (remote)) \
+	    (local)->anvil_remote = 0; \
+    } while(0)
+
+/* Drop all remote connections from local server. */
+
+#define ANVIL_LOCAL_DROP_ALL(stream, local) \
+    do { \
+	 /* XXX allow multiple remote clients per local server. */ \
+	if ((local)->anvil_remote) \
+	    anvil_remote_disconnect((stream), (local)->anvil_remote->ident); \
+    } while (0)
+
+ /*
+  * Lookup table to map request names to action routines.
+  */
+typedef struct {
+    const char *name;
+    void    (*action) (VSTREAM *, const char *);
+} ANVIL_REQ_TABLE;
+
+ /*
+  * Run-time statistics for maximal connection counts and event rates. These
+  * store the peak resource usage, remote connection, and time. Absent a
+  * query interface, this information is logged at process exit time and at
+  * configurable intervals.
+  */
+typedef struct {
+    int     value;			/* peak value */
+    char   *ident;			/* lookup key */
+    time_t  when;			/* time of peak value */
+} ANVIL_MAX;
+
+static ANVIL_MAX max_conn_count;	/* peak connection count */
+static ANVIL_MAX max_conn_rate;		/* peak connection rate */
+static ANVIL_MAX max_mail_rate;		/* peak message rate */
+static ANVIL_MAX max_rcpt_rate;		/* peak recipient rate */
+static ANVIL_MAX max_ntls_rate;		/* peak new TLS session rate */
+static ANVIL_MAX max_auth_rate;		/* peak AUTH request rate */
+
+static int max_cache_size;		/* peak cache size */
+static time_t max_cache_time;		/* time of peak size */
+
+/* Update/report peak usage. */
+
+#define ANVIL_MAX_UPDATE(_max, _value, _ident) \
+    do { \
+	_max.value = _value; \
+	if (_max.ident == 0) { \
+	    _max.ident = mystrdup(_ident); \
+	} else if (!STREQ(_max.ident, _ident)) { \
+	    myfree(_max.ident); \
+	    _max.ident = mystrdup(_ident); \
+	} \
+	_max.when = event_time(); \
+    } while (0)
+
+#define ANVIL_MAX_RATE_REPORT(_max, _name) \
+    do { \
+	if (_max.value > 0) { \
+	    msg_info("statistics: max " _name " rate %d/%ds for (%s) at %.15s", \
+		_max.value, var_anvil_time_unit, \
+		_max.ident, ctime(&_max.when) + 4); \
+	    _max.value = 0; \
+	} \
+    } while (0);
+
+#define ANVIL_MAX_COUNT_REPORT(_max, _name) \
+    do { \
+	if (_max.value > 0) { \
+	    msg_info("statistics: max " _name " count %d for (%s) at %.15s", \
+		_max.value, _max.ident, ctime(&_max.when) + 4); \
+	    _max.value = 0; \
+	} \
+    } while (0);
+
+ /*
+  * Silly little macros.
+  */
+#define STR(x)			vstring_str(x)
+#define STREQ(x,y)		(strcmp((x), (y)) == 0)
+
+/* anvil_remote_expire - purge expired connection state */
+
+static void anvil_remote_expire(int unused_event, void *context)
+{
+    ANVIL_REMOTE *anvil_remote = (ANVIL_REMOTE *) context;
+    const char *myname = "anvil_remote_expire";
+
+    if (msg_verbose)
+	msg_info("%s %s", myname, anvil_remote->ident);
+
+    if (anvil_remote->count != 0)
+	msg_panic("%s: bad connection count: %d",
+		  myname, anvil_remote->count);
+
+    htable_delete(anvil_remote_map, anvil_remote->ident,
+		  (void (*) (void *)) 0);
+    ANVIL_REMOTE_FREE(anvil_remote);
+
+    if (msg_verbose)
+	msg_info("%s: anvil_remote_map used=%ld",
+		 myname, (long) anvil_remote_map->used);
+}
+
+/* anvil_remote_lookup - dump address status */
+
+static void anvil_remote_lookup(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+    const char *myname = "anvil_remote_lookup";
+
+    if (msg_verbose)
+	msg_info("%s fd=%d stream=0x%lx ident=%s",
+		 myname, vstream_fileno(client_stream),
+		 (unsigned long) client_stream, ident);
+
+    /*
+     * Look up remote client information.
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0) {
+	attr_print_plain(client_stream, ATTR_FLAG_NONE,
+			 SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+			 SEND_ATTR_INT(ANVIL_ATTR_COUNT, 0),
+			 SEND_ATTR_INT(ANVIL_ATTR_RATE, 0),
+			 SEND_ATTR_INT(ANVIL_ATTR_MAIL, 0),
+			 SEND_ATTR_INT(ANVIL_ATTR_RCPT, 0),
+			 SEND_ATTR_INT(ANVIL_ATTR_NTLS, 0),
+			 SEND_ATTR_INT(ANVIL_ATTR_AUTH, 0),
+			 ATTR_TYPE_END);
+    } else {
+
+	/*
+	 * Do not report stale information.
+	 */
+	if (anvil_remote->start != 0
+	    && anvil_remote->start + var_anvil_time_unit < event_time())
+	    ANVIL_REMOTE_RSET_RATE(anvil_remote, 0);
+	attr_print_plain(client_stream, ATTR_FLAG_NONE,
+			 SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		       SEND_ATTR_INT(ANVIL_ATTR_COUNT, anvil_remote->count),
+			 SEND_ATTR_INT(ANVIL_ATTR_RATE, anvil_remote->rate),
+			 SEND_ATTR_INT(ANVIL_ATTR_MAIL, anvil_remote->mail),
+			 SEND_ATTR_INT(ANVIL_ATTR_RCPT, anvil_remote->rcpt),
+			 SEND_ATTR_INT(ANVIL_ATTR_NTLS, anvil_remote->ntls),
+			 SEND_ATTR_INT(ANVIL_ATTR_AUTH, anvil_remote->auth),
+			 ATTR_TYPE_END);
+    }
+}
+
+/* anvil_remote_conn_update - instantiate or update connection info */
+
+static ANVIL_REMOTE *anvil_remote_conn_update(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+    ANVIL_LOCAL *anvil_local;
+    const char *myname = "anvil_remote_conn_update";
+
+    if (msg_verbose)
+	msg_info("%s fd=%d stream=0x%lx ident=%s",
+		 myname, vstream_fileno(client_stream),
+		 (unsigned long) client_stream, ident);
+
+    /*
+     * Look up remote connection count information. Update remote connection
+     * rate information. Simply reset the counter every var_anvil_time_unit
+     * seconds. This is easier than maintaining a moving average and it gives
+     * a quicker response to tresspassers.
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0) {
+	anvil_remote = (ANVIL_REMOTE *) mymalloc(sizeof(*anvil_remote));
+	ANVIL_REMOTE_FIRST_CONN(anvil_remote, ident);
+	htable_enter(anvil_remote_map, ident, (void *) anvil_remote);
+	if (max_cache_size < anvil_remote_map->used) {
+	    max_cache_size = anvil_remote_map->used;
+	    max_cache_time = event_time();
+	}
+    } else {
+	ANVIL_REMOTE_NEXT_CONN(anvil_remote);
+    }
+
+    /*
+     * Record this connection under the local server information, so that we
+     * can clean up all its connection state when the local server goes away.
+     */
+    if ((anvil_local = (ANVIL_LOCAL *) vstream_context(client_stream)) == 0) {
+	anvil_local = (ANVIL_LOCAL *) mymalloc(sizeof(*anvil_local));
+	ANVIL_LOCAL_INIT(anvil_local);
+	vstream_control(client_stream,
+			CA_VSTREAM_CTL_CONTEXT((void *) anvil_local),
+			CA_VSTREAM_CTL_END);
+    }
+    ANVIL_LOCAL_ADD_ONE(anvil_local, anvil_remote);
+    if (msg_verbose)
+	msg_info("%s: anvil_local 0x%lx",
+		 myname, (unsigned long) anvil_local);
+
+    return (anvil_remote);
+}
+
+/* anvil_remote_connect - report connection event, query address status */
+
+static void anvil_remote_connect(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+
+    /*
+     * Update or instantiate connection info.
+     */
+    anvil_remote = anvil_remote_conn_update(client_stream, ident);
+
+    /*
+     * Respond to the local server.
+     */
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     SEND_ATTR_INT(ANVIL_ATTR_COUNT, anvil_remote->count),
+		     SEND_ATTR_INT(ANVIL_ATTR_RATE, anvil_remote->rate),
+		     ATTR_TYPE_END);
+
+    /*
+     * Update peak statistics.
+     */
+    if (anvil_remote->rate > max_conn_rate.value)
+	ANVIL_MAX_UPDATE(max_conn_rate, anvil_remote->rate, anvil_remote->ident);
+    if (anvil_remote->count > max_conn_count.value)
+	ANVIL_MAX_UPDATE(max_conn_count, anvil_remote->count, anvil_remote->ident);
+}
+
+/* anvil_remote_mail - register message delivery request */
+
+static void anvil_remote_mail(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+
+    /*
+     * Be prepared for "postfix reload" after "connect".
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0)
+	anvil_remote = anvil_remote_conn_update(client_stream, ident);
+
+    /*
+     * Update message delivery request rate and respond to local server.
+     */
+    ANVIL_REMOTE_INCR_MAIL(anvil_remote);
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     SEND_ATTR_INT(ANVIL_ATTR_RATE, anvil_remote->mail),
+		     ATTR_TYPE_END);
+
+    /*
+     * Update peak statistics.
+     */
+    if (anvil_remote->mail > max_mail_rate.value)
+	ANVIL_MAX_UPDATE(max_mail_rate, anvil_remote->mail, anvil_remote->ident);
+}
+
+/* anvil_remote_rcpt - register recipient address event */
+
+static void anvil_remote_rcpt(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+
+    /*
+     * Be prepared for "postfix reload" after "connect".
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0)
+	anvil_remote = anvil_remote_conn_update(client_stream, ident);
+
+    /*
+     * Update recipient address rate and respond to local server.
+     */
+    ANVIL_REMOTE_INCR_RCPT(anvil_remote);
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     SEND_ATTR_INT(ANVIL_ATTR_RATE, anvil_remote->rcpt),
+		     ATTR_TYPE_END);
+
+    /*
+     * Update peak statistics.
+     */
+    if (anvil_remote->rcpt > max_rcpt_rate.value)
+	ANVIL_MAX_UPDATE(max_rcpt_rate, anvil_remote->rcpt, anvil_remote->ident);
+}
+
+/* anvil_remote_auth - register auth request event */
+
+static void anvil_remote_auth(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+
+    /*
+     * Be prepared for "postfix reload" after "connect".
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0)
+	anvil_remote = anvil_remote_conn_update(client_stream, ident);
+
+    /*
+     * Update recipient address rate and respond to local server.
+     */
+    ANVIL_REMOTE_INCR_AUTH(anvil_remote);
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     SEND_ATTR_INT(ANVIL_ATTR_RATE, anvil_remote->auth),
+		     ATTR_TYPE_END);
+
+    /*
+     * Update peak statistics.
+     */
+    if (anvil_remote->auth > max_auth_rate.value)
+	ANVIL_MAX_UPDATE(max_auth_rate, anvil_remote->auth, anvil_remote->ident);
+}
+
+/* anvil_remote_newtls - register newtls event */
+
+static void anvil_remote_newtls(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+
+    /*
+     * Be prepared for "postfix reload" after "connect".
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0)
+	anvil_remote = anvil_remote_conn_update(client_stream, ident);
+
+    /*
+     * Update newtls rate and respond to local server.
+     */
+    ANVIL_REMOTE_INCR_NTLS(anvil_remote);
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     SEND_ATTR_INT(ANVIL_ATTR_RATE, anvil_remote->ntls),
+		     ATTR_TYPE_END);
+
+    /*
+     * Update peak statistics.
+     */
+    if (anvil_remote->ntls > max_ntls_rate.value)
+	ANVIL_MAX_UPDATE(max_ntls_rate, anvil_remote->ntls, anvil_remote->ident);
+}
+
+/* anvil_remote_newtls_stat - report newtls stats */
+
+static void anvil_remote_newtls_stat(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+    int     rate;
+
+    /*
+     * Be prepared for "postfix reload" after "connect".
+     */
+    if ((anvil_remote =
+	 (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) == 0) {
+	rate = 0;
+    }
+
+    /*
+     * Do not report stale information.
+     */
+    else {
+	if (anvil_remote->start != 0
+	    && anvil_remote->start + var_anvil_time_unit < event_time())
+	    ANVIL_REMOTE_RSET_RATE(anvil_remote, 0);
+	rate = anvil_remote->ntls;
+    }
+
+    /*
+     * Respond to local server.
+     */
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     SEND_ATTR_INT(ANVIL_ATTR_RATE, rate),
+		     ATTR_TYPE_END);
+}
+
+/* anvil_remote_disconnect - report disconnect event */
+
+static void anvil_remote_disconnect(VSTREAM *client_stream, const char *ident)
+{
+    ANVIL_REMOTE *anvil_remote;
+    ANVIL_LOCAL *anvil_local;
+    const char *myname = "anvil_remote_disconnect";
+
+    if (msg_verbose)
+	msg_info("%s fd=%d stream=0x%lx ident=%s",
+		 myname, vstream_fileno(client_stream),
+		 (unsigned long) client_stream, ident);
+
+    /*
+     * Update local and remote info if this remote connection is listed for
+     * this local server.
+     */
+    if ((anvil_local = (ANVIL_LOCAL *) vstream_context(client_stream)) != 0
+	&& (anvil_remote =
+	    (ANVIL_REMOTE *) htable_find(anvil_remote_map, ident)) != 0
+	&& ANVIL_LOCAL_REMOTE_LINKED(anvil_local, anvil_remote)) {
+	ANVIL_REMOTE_DROP_ONE(anvil_remote);
+	ANVIL_LOCAL_DROP_ONE(anvil_local, anvil_remote);
+    }
+    if (msg_verbose)
+	msg_info("%s: anvil_local 0x%lx",
+		 myname, (unsigned long) anvil_local);
+
+    /*
+     * Respond to the local server.
+     */
+    attr_print_plain(client_stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_OK),
+		     ATTR_TYPE_END);
+}
+
+/* anvil_service_done - clean up */
+
+static void anvil_service_done(VSTREAM *client_stream, char *unused_service,
+			               char **unused_argv)
+{
+    ANVIL_LOCAL *anvil_local;
+    const char *myname = "anvil_service_done";
+
+    if (msg_verbose)
+	msg_info("%s fd=%d stream=0x%lx",
+		 myname, vstream_fileno(client_stream),
+		 (unsigned long) client_stream);
+
+    /*
+     * Look up the local server, and get rid of any remote connection state
+     * that we still have for this local server. Do not destroy remote client
+     * status information before it expires.
+     */
+    if ((anvil_local = (ANVIL_LOCAL *) vstream_context(client_stream)) != 0) {
+	if (msg_verbose)
+	    msg_info("%s: anvil_local 0x%lx",
+		     myname, (unsigned long) anvil_local);
+	ANVIL_LOCAL_DROP_ALL(client_stream, anvil_local);
+	myfree((void *) anvil_local);
+    } else if (msg_verbose)
+	msg_info("client socket not found for fd=%d",
+		 vstream_fileno(client_stream));
+}
+
+/* anvil_status_dump - log and reset extreme usage */
+
+static void anvil_status_dump(char *unused_name, char **unused_argv)
+{
+    ANVIL_MAX_RATE_REPORT(max_conn_rate, "connection");
+    ANVIL_MAX_COUNT_REPORT(max_conn_count, "connection");
+    ANVIL_MAX_RATE_REPORT(max_mail_rate, "message");
+    ANVIL_MAX_RATE_REPORT(max_rcpt_rate, "recipient");
+    ANVIL_MAX_RATE_REPORT(max_ntls_rate, "newtls");
+    ANVIL_MAX_RATE_REPORT(max_auth_rate, "auth");
+
+    if (max_cache_size > 0) {
+	msg_info("statistics: max cache size %d at %.15s",
+		 max_cache_size, ctime(&max_cache_time) + 4);
+	max_cache_size = 0;
+    }
+}
+
+/* anvil_status_update - log and reset extreme usage periodically */
+
+static void anvil_status_update(int unused_event, void *context)
+{
+    anvil_status_dump((char *) 0, (char **) 0);
+    event_request_timer(anvil_status_update, context, var_anvil_stat_time);
+}
+
+/* anvil_service - perform service for client */
+
+static void anvil_service(VSTREAM *client_stream, char *unused_service, char **argv)
+{
+    static VSTRING *request;
+    static VSTRING *ident;
+    static const ANVIL_REQ_TABLE request_table[] = {
+	ANVIL_REQ_CONN, anvil_remote_connect,
+	ANVIL_REQ_MAIL, anvil_remote_mail,
+	ANVIL_REQ_RCPT, anvil_remote_rcpt,
+	ANVIL_REQ_NTLS, anvil_remote_newtls,
+	ANVIL_REQ_DISC, anvil_remote_disconnect,
+	ANVIL_REQ_NTLS_STAT, anvil_remote_newtls_stat,
+	ANVIL_REQ_AUTH, anvil_remote_auth,
+	ANVIL_REQ_LOOKUP, anvil_remote_lookup,
+	0, 0,
+    };
+    const ANVIL_REQ_TABLE *rp;
+
+    /*
+     * Sanity check. This service takes no command-line arguments.
+     */
+    if (argv[0])
+	msg_fatal("unexpected command-line argument: %s", argv[0]);
+
+    /*
+     * Initialize.
+     */
+    if (request == 0) {
+	request = vstring_alloc(10);
+	ident = vstring_alloc(10);
+    }
+
+    /*
+     * This routine runs whenever a client connects to the socket dedicated
+     * to the client connection rate management service. All
+     * connection-management stuff is handled by the common code in
+     * multi_server.c.
+     */
+    if (msg_verbose)
+	msg_info("--- start request ---");
+    if (attr_scan_plain(client_stream,
+			ATTR_FLAG_MISSING | ATTR_FLAG_STRICT,
+			RECV_ATTR_STR(ANVIL_ATTR_REQ, request),
+			RECV_ATTR_STR(ANVIL_ATTR_IDENT, ident),
+			ATTR_TYPE_END) == 2) {
+	for (rp = request_table; /* see below */ ; rp++) {
+	    if (rp->name == 0) {
+		msg_warn("unrecognized request: \"%s\", ignored", STR(request));
+		attr_print_plain(client_stream, ATTR_FLAG_NONE,
+			  SEND_ATTR_INT(ANVIL_ATTR_STATUS, ANVIL_STAT_FAIL),
+				 ATTR_TYPE_END);
+		break;
+	    }
+	    if (STREQ(rp->name, STR(request))) {
+		rp->action(client_stream, STR(ident));
+		break;
+	    }
+	}
+	vstream_fflush(client_stream);
+    } else {
+	/* Note: invokes anvil_service_done() */
+	multi_server_disconnect(client_stream);
+    }
+    if (msg_verbose)
+	msg_info("--- end request ---");
+}
+
+/* post_jail_init - post-jail initialization */
+
+static void post_jail_init(char *unused_name, char **unused_argv)
+{
+
+    /*
+     * Dump and reset extreme usage every so often.
+     */
+    event_request_timer(anvil_status_update, (void *) 0, var_anvil_stat_time);
+
+    /*
+     * Initial client state tables.
+     */
+    anvil_remote_map = htable_create(1000);
+
+    /*
+     * Do not limit the number of client requests.
+     */
+    var_use_limit = 0;
+
+    /*
+     * Don't exit before the sampling interval ends.
+     */
+    if (var_idle_limit < var_anvil_time_unit)
+	var_idle_limit = var_anvil_time_unit;
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* post_accept - announce our protocol */
+
+static void post_accept(VSTREAM *stream, char *unused_name,
+			        char **unused_argv, HTABLE *unused_table)
+{
+
+    /*
+     * Announce the protocol.
+     */
+    attr_print_plain(stream, ATTR_FLAG_NONE,
+		     SEND_ATTR_STR(MAIL_ATTR_PROTO, MAIL_ATTR_PROTO_ANVIL),
+		     ATTR_TYPE_END);
+    (void) vstream_fflush(stream);
+}
+
+/* main - pass control to the multi-threaded skeleton */
+
+int     main(int argc, char **argv)
+{
+    static const CONFIG_TIME_TABLE time_table[] = {
+	VAR_ANVIL_TIME_UNIT, DEF_ANVIL_TIME_UNIT, &var_anvil_time_unit, 1, 0,
+	VAR_ANVIL_STAT_TIME, DEF_ANVIL_STAT_TIME, &var_anvil_stat_time, 1, 0,
+	0,
+    };
+
+    /*
+     * Fingerprint executables and core dumps.
+     */
+    MAIL_VERSION_STAMP_ALLOCATE;
+
+    multi_server_main(argc, argv, anvil_service,
+		      CA_MAIL_SERVER_TIME_TABLE(time_table),
+		      CA_MAIL_SERVER_POST_INIT(post_jail_init),
+		      CA_MAIL_SERVER_POST_ACCEPT(post_accept),
+		      CA_MAIL_SERVER_SOLITARY,
+		      CA_MAIL_SERVER_PRE_DISCONN(anvil_service_done),
+		      CA_MAIL_SERVER_EXIT(anvil_status_dump),
+		      0);
+}