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Diffstat (limited to 'src/scache/scache.c')
| -rw-r--r-- | src/scache/scache.c | 586 |
1 files changed, 586 insertions, 0 deletions
diff --git a/src/scache/scache.c b/src/scache/scache.c new file mode 100644 index 0000000..85f32ef --- /dev/null +++ b/src/scache/scache.c @@ -0,0 +1,586 @@ +/*++ +/* NAME +/* scache 8 +/* SUMMARY +/* Postfix shared connection cache server +/* SYNOPSIS +/* \fBscache\fR [generic Postfix daemon options] +/* DESCRIPTION +/* The \fBscache\fR(8) server maintains a shared multi-connection +/* cache. This information can be used by, for example, Postfix +/* SMTP clients or other Postfix delivery agents. +/* +/* The connection cache is organized into logical destination +/* names, physical endpoint names, and connections. +/* +/* As a specific example, logical SMTP destinations specify +/* (transport, domain, port), and physical SMTP endpoints +/* specify (transport, IP address, port). An SMTP connection +/* may be saved after a successful mail transaction. +/* +/* In the general case, one logical destination may refer to +/* zero or more physical endpoints, one physical endpoint may +/* be referenced by zero or more logical destinations, and +/* one endpoint may refer to zero or more connections. +/* +/* The exact syntax of a logical destination or endpoint name +/* is application dependent; the \fBscache\fR(8) server does +/* not care. A connection is stored as a file descriptor together +/* with application-dependent information that is needed to +/* re-activate a connection object. Again, the \fBscache\fR(8) +/* server is completely unaware of the details of that +/* information. +/* +/* All information is stored with a finite time to live (ttl). +/* The connection cache daemon terminates when no client is +/* connected for \fBmax_idle\fR time units. +/* +/* This server implements the following requests: +/* .IP "\fBsave_endp\fI ttl endpoint endpoint_properties file_descriptor\fR" +/* Save the specified file descriptor and connection property data +/* under the specified endpoint name. The endpoint properties +/* are used by the client to re-activate a passivated connection +/* object. +/* .IP "\fBfind_endp\fI endpoint\fR" +/* Look up cached properties and a cached file descriptor for the +/* specified endpoint. +/* .IP "\fBsave_dest\fI ttl destination destination_properties endpoint\fR" +/* Save the binding between a logical destination and an +/* endpoint under the destination name, together with destination +/* specific connection properties. The destination properties +/* are used by the client to re-activate a passivated connection +/* object. +/* .IP "\fBfind_dest\fI destination\fR" +/* Look up cached destination properties, cached endpoint properties, +/* and a cached file descriptor for the specified logical destination. +/* SECURITY +/* .ad +/* .fi +/* The \fBscache\fR(8) server is not security-sensitive. It does not +/* talk to the network, and it does not talk to local users. +/* The \fBscache\fR(8) server can run chrooted at fixed low privilege. +/* +/* The \fBscache\fR(8) server is not a trusted process. It must +/* not be used to store information that is security sensitive. +/* DIAGNOSTICS +/* Problems and transactions are logged to \fBsyslogd\fR(8) +/* or \fBpostlogd\fR(8). +/* BUGS +/* The session cache cannot be shared among multiple machines. +/* +/* When a connection expires from the cache, it is closed without +/* the appropriate protocol specific handshake. +/* CONFIGURATION PARAMETERS +/* .ad +/* .fi +/* Changes to \fBmain.cf\fR are picked up automatically as \fBscache\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. +/* RESOURCE CONTROLS +/* .ad +/* .fi +/* .IP "\fBconnection_cache_ttl_limit (2s)\fR" +/* The maximal time-to-live value that the \fBscache\fR(8) connection +/* cache server +/* allows. +/* .IP "\fBconnection_cache_status_update_time (600s)\fR" +/* How frequently the \fBscache\fR(8) server logs usage statistics with +/* connection cache hit and miss rates for logical destinations and for +/* physical endpoints. +/* MISCELLANEOUS CONTROLS +/* .ad +/* .fi +/* .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 "\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 +/* smtp(8), SMTP client +/* postconf(5), configuration parameters +/* master(8), process manager +/* 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 +/* CONNECTION_CACHE_README, Postfix connection cache +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* HISTORY +/* This service was introduced with Postfix version 2.2. +/* 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 <time.h> + +/* Utility library. */ + +#include <msg.h> +#include <iostuff.h> +#include <htable.h> +#include <ring.h> +#include <events.h> + +/* Global library. */ + +#include <mail_params.h> +#include <mail_version.h> +#include <mail_proto.h> +#include <scache.h> + +/* Single server skeleton. */ + +#include <mail_server.h> +#include <mail_conf.h> + +/* Application-specific. */ + + /* + * Tunable parameters. + */ +int var_scache_ttl_lim; +int var_scache_stat_time; + + /* + * Request parameters. + */ +static VSTRING *scache_request; +static VSTRING *scache_dest_label; +static VSTRING *scache_dest_prop; +static VSTRING *scache_endp_label; +static VSTRING *scache_endp_prop; + +#ifdef CANT_WRITE_BEFORE_SENDING_FD +static VSTRING *scache_dummy; + +#endif + + /* + * Session cache instance. + */ +static SCACHE *scache; + + /* + * Statistics. + */ +static int scache_dest_hits; +static int scache_dest_miss; +static int scache_dest_count; +static int scache_endp_hits; +static int scache_endp_miss; +static int scache_endp_count; +static int scache_sess_count; +time_t scache_start_time; + + /* + * Silly little macros. + */ +#define STR(x) vstring_str(x) +#define VSTREQ(x,y) (strcmp(STR(x),y) == 0) + +/* scache_save_endp_service - protocol to save endpoint->stream binding */ + +static void scache_save_endp_service(VSTREAM *client_stream) +{ + const char *myname = "scache_save_endp_service"; + int ttl; + int fd; + SCACHE_SIZE size; + + if (attr_scan(client_stream, + ATTR_FLAG_STRICT, + RECV_ATTR_INT(MAIL_ATTR_TTL, &ttl), + RECV_ATTR_STR(MAIL_ATTR_LABEL, scache_endp_label), + RECV_ATTR_STR(MAIL_ATTR_PROP, scache_endp_prop), + ATTR_TYPE_END) != 3 + || ttl <= 0) { + msg_warn("%s: bad or missing request parameter", myname); + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_BAD), + ATTR_TYPE_END); + return; + } else if ( +#ifdef CANT_WRITE_BEFORE_SENDING_FD + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_STR(MAIL_ATTR_DUMMY, ""), + ATTR_TYPE_END) != 0 + || vstream_fflush(client_stream) != 0 + || read_wait(vstream_fileno(client_stream), + client_stream->timeout) < 0 /* XXX */ + || +#endif + (fd = LOCAL_RECV_FD(vstream_fileno(client_stream))) < 0) { + msg_warn("%s: unable to receive file descriptor: %m", myname); + (void) attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_FAIL), + ATTR_TYPE_END); + return; + } else { + scache_save_endp(scache, + ttl > var_scache_ttl_lim ? var_scache_ttl_lim : ttl, + STR(scache_endp_label), STR(scache_endp_prop), fd); + (void) attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_OK), + ATTR_TYPE_END); + scache_size(scache, &size); + if (size.endp_count > scache_endp_count) + scache_endp_count = size.endp_count; + if (size.sess_count > scache_sess_count) + scache_sess_count = size.sess_count; + return; + } +} + +/* scache_find_endp_service - protocol to find connection for endpoint */ + +static void scache_find_endp_service(VSTREAM *client_stream) +{ + const char *myname = "scache_find_endp_service"; + int fd; + + if (attr_scan(client_stream, + ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_LABEL, scache_endp_label), + ATTR_TYPE_END) != 1) { + msg_warn("%s: bad or missing request parameter", myname); + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_BAD), + SEND_ATTR_STR(MAIL_ATTR_PROP, ""), + ATTR_TYPE_END); + return; + } else if ((fd = scache_find_endp(scache, STR(scache_endp_label), + scache_endp_prop)) < 0) { + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_FAIL), + SEND_ATTR_STR(MAIL_ATTR_PROP, ""), + ATTR_TYPE_END); + scache_endp_miss++; + return; + } else { + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_OK), + SEND_ATTR_STR(MAIL_ATTR_PROP, STR(scache_endp_prop)), + ATTR_TYPE_END); + if (vstream_fflush(client_stream) != 0 +#ifdef CANT_WRITE_BEFORE_SENDING_FD + || attr_scan(client_stream, ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_DUMMY, scache_dummy), + ATTR_TYPE_END) != 1 +#endif + || LOCAL_SEND_FD(vstream_fileno(client_stream), fd) < 0 +#ifdef MUST_READ_AFTER_SENDING_FD + || attr_scan(client_stream, ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_DUMMY, scache_dummy), + ATTR_TYPE_END) != 1 +#endif + ) + msg_warn("%s: cannot send file descriptor: %m", myname); + if (close(fd) < 0) + msg_warn("close(%d): %m", fd); + scache_endp_hits++; + return; + } +} + +/* scache_save_dest_service - protocol to save destination->endpoint binding */ + +static void scache_save_dest_service(VSTREAM *client_stream) +{ + const char *myname = "scache_save_dest_service"; + int ttl; + SCACHE_SIZE size; + + if (attr_scan(client_stream, + ATTR_FLAG_STRICT, + RECV_ATTR_INT(MAIL_ATTR_TTL, &ttl), + RECV_ATTR_STR(MAIL_ATTR_LABEL, scache_dest_label), + RECV_ATTR_STR(MAIL_ATTR_PROP, scache_dest_prop), + RECV_ATTR_STR(MAIL_ATTR_LABEL, scache_endp_label), + ATTR_TYPE_END) != 4 + || ttl <= 0) { + msg_warn("%s: bad or missing request parameter", myname); + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_BAD), + ATTR_TYPE_END); + return; + } else { + scache_save_dest(scache, + ttl > var_scache_ttl_lim ? var_scache_ttl_lim : ttl, + STR(scache_dest_label), STR(scache_dest_prop), + STR(scache_endp_label)); + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_OK), + ATTR_TYPE_END); + scache_size(scache, &size); + if (size.dest_count > scache_dest_count) + scache_dest_count = size.dest_count; + if (size.endp_count > scache_endp_count) + scache_endp_count = size.endp_count; + return; + } +} + +/* scache_find_dest_service - protocol to find connection for destination */ + +static void scache_find_dest_service(VSTREAM *client_stream) +{ + const char *myname = "scache_find_dest_service"; + int fd; + + if (attr_scan(client_stream, + ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_LABEL, scache_dest_label), + ATTR_TYPE_END) != 1) { + msg_warn("%s: bad or missing request parameter", myname); + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_BAD), + SEND_ATTR_STR(MAIL_ATTR_PROP, ""), + SEND_ATTR_STR(MAIL_ATTR_PROP, ""), + ATTR_TYPE_END); + return; + } else if ((fd = scache_find_dest(scache, STR(scache_dest_label), + scache_dest_prop, + scache_endp_prop)) < 0) { + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_FAIL), + SEND_ATTR_STR(MAIL_ATTR_PROP, ""), + SEND_ATTR_STR(MAIL_ATTR_PROP, ""), + ATTR_TYPE_END); + scache_dest_miss++; + return; + } else { + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_OK), + SEND_ATTR_STR(MAIL_ATTR_PROP, STR(scache_dest_prop)), + SEND_ATTR_STR(MAIL_ATTR_PROP, STR(scache_endp_prop)), + ATTR_TYPE_END); + if (vstream_fflush(client_stream) != 0 +#ifdef CANT_WRITE_BEFORE_SENDING_FD + || attr_scan(client_stream, ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_DUMMY, scache_dummy), + ATTR_TYPE_END) != 1 +#endif + || LOCAL_SEND_FD(vstream_fileno(client_stream), fd) < 0 +#ifdef MUST_READ_AFTER_SENDING_FD + || attr_scan(client_stream, ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_DUMMY, scache_dummy), + ATTR_TYPE_END) != 1 +#endif + ) + msg_warn("%s: cannot send file descriptor: %m", myname); + if (close(fd) < 0) + msg_warn("close(%d): %m", fd); + scache_dest_hits++; + return; + } +} + +/* scache_service - perform service for client */ + +static void scache_service(VSTREAM *client_stream, char *unused_service, + char **argv) +{ + + /* + * 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 the scache service. All connection-management stuff is + * handled by the common code in multi_server.c. + * + * XXX Workaround: with some requests, the client sends a dummy message + * after the server replies (yes that's a botch). When the scache server + * is slow, this dummy message may become concatenated with the next + * request from the same client. The do-while loop below will repeat + * instead of discarding the client request. We must process it now + * because there will be no select() notification. + */ + do { + if (attr_scan(client_stream, + ATTR_FLAG_MORE | ATTR_FLAG_STRICT, + RECV_ATTR_STR(MAIL_ATTR_REQ, scache_request), + ATTR_TYPE_END) == 1) { + if (VSTREQ(scache_request, SCACHE_REQ_SAVE_DEST)) { + scache_save_dest_service(client_stream); + } else if (VSTREQ(scache_request, SCACHE_REQ_FIND_DEST)) { + scache_find_dest_service(client_stream); + } else if (VSTREQ(scache_request, SCACHE_REQ_SAVE_ENDP)) { + scache_save_endp_service(client_stream); + } else if (VSTREQ(scache_request, SCACHE_REQ_FIND_ENDP)) { + scache_find_endp_service(client_stream); + } else { + msg_warn("unrecognized request: \"%s\", ignored", + STR(scache_request)); + attr_print(client_stream, ATTR_FLAG_NONE, + SEND_ATTR_INT(MAIL_ATTR_STATUS, SCACHE_STAT_BAD), + ATTR_TYPE_END); + } + } + } while (vstream_peek(client_stream) > 0); + vstream_fflush(client_stream); +} + +/* scache_status_dump - log and reset cache statistics */ + +static void scache_status_dump(char *unused_name, char **unused_argv) +{ + if (scache_dest_hits || scache_dest_miss + || scache_endp_hits || scache_endp_miss + || scache_dest_count || scache_endp_count + || scache_sess_count) + msg_info("statistics: start interval %.15s", + ctime(&scache_start_time) + 4); + + if (scache_dest_hits || scache_dest_miss) { + msg_info("statistics: domain lookup hits=%d miss=%d success=%d%%", + scache_dest_hits, scache_dest_miss, + scache_dest_hits * 100 + / (scache_dest_hits + scache_dest_miss)); + scache_dest_hits = scache_dest_miss = 0; + } + if (scache_endp_hits || scache_endp_miss) { + msg_info("statistics: address lookup hits=%d miss=%d success=%d%%", + scache_endp_hits, scache_endp_miss, + scache_endp_hits * 100 + / (scache_endp_hits + scache_endp_miss)); + scache_endp_hits = scache_endp_miss = 0; + } + if (scache_dest_count || scache_endp_count || scache_sess_count) { + msg_info("statistics: max simultaneous domains=%d addresses=%d connection=%d", + scache_dest_count, scache_endp_count, scache_sess_count); + scache_dest_count = 0; + scache_endp_count = 0; + scache_sess_count = 0; + } + scache_start_time = event_time(); +} + +/* scache_status_update - log and reset cache statistics periodically */ + +static void scache_status_update(int unused_event, void *context) +{ + scache_status_dump((char *) 0, (char **) 0); + event_request_timer(scache_status_update, context, var_scache_stat_time); +} + +/* post_jail_init - initialization after privilege drop */ + +static void post_jail_init(char *unused_name, char **unused_argv) +{ + + /* + * Pre-allocate the cache instance. + */ + scache = scache_multi_create(); + + /* + * Pre-allocate buffers. + */ + scache_request = vstring_alloc(10); + scache_dest_label = vstring_alloc(10); + scache_dest_prop = vstring_alloc(10); + scache_endp_label = vstring_alloc(10); + scache_endp_prop = vstring_alloc(10); +#ifdef CANT_WRITE_BEFORE_SENDING_FD + scache_dummy = vstring_alloc(10); +#endif + + /* + * Disable the max_use limit. We still terminate when no client is + * connected for $idle_limit time units. + */ + var_use_limit = 0; + + /* + * Dump and reset cache statistics every so often. + */ + event_request_timer(scache_status_update, (void *) 0, var_scache_stat_time); + scache_start_time = event_time(); +} + +/* scache_post_accept - announce our protocol */ + +static void scache_post_accept(VSTREAM *stream, char *unused_name, + char **unused_argv, HTABLE *unused_table) +{ + + /* + * Announce the protocol. + */ + attr_print(stream, ATTR_FLAG_NONE, + SEND_ATTR_STR(MAIL_ATTR_PROTO, MAIL_ATTR_PROTO_SCACHE), + ATTR_TYPE_END); + (void) vstream_fflush(stream); +} + +MAIL_VERSION_STAMP_DECLARE; + +/* main - pass control to the multi-threaded skeleton */ + +int main(int argc, char **argv) +{ + static const CONFIG_TIME_TABLE time_table[] = { + VAR_SCACHE_TTL_LIM, DEF_SCACHE_TTL_LIM, &var_scache_ttl_lim, 1, 0, + VAR_SCACHE_STAT_TIME, DEF_SCACHE_STAT_TIME, &var_scache_stat_time, 1, 0, + 0, + }; + + /* + * Fingerprint executables and core dumps. + */ + MAIL_VERSION_STAMP_ALLOCATE; + + multi_server_main(argc, argv, scache_service, + CA_MAIL_SERVER_TIME_TABLE(time_table), + CA_MAIL_SERVER_POST_INIT(post_jail_init), + CA_MAIL_SERVER_POST_ACCEPT(scache_post_accept), + CA_MAIL_SERVER_EXIT(scache_status_dump), + CA_MAIL_SERVER_SOLITARY, + 0); +} |