Gitweb:
https://git.exim.org/exim.git/commitdiff/9d783bb9f39bca59e720d0c543499b372c412441
Commit: 9d783bb9f39bca59e720d0c543499b372c412441
Parent: 936fcb6fc957910826dc7f2fc349cdc0c3a456d6
Author: Jeremy Harris <jgh146exb@???>
AuthorDate: Sun Jun 6 19:58:48 2021 +0100
Committer: Jeremy Harris <jgh146exb@???>
CommitDate: Sun Jun 6 21:13:15 2021 +0100
Observability: listen queue backlog
---
doc/doc-docbook/spec.xfpt | 11 ++++++++++-
doc/doc-txt/NewStuff | 3 +++
doc/doc-txt/OptionLists.txt | 1 +
src/src/daemon.c | 40 +++++++++++++++++++++++++++++++++-------
src/src/globals.c | 2 ++
src/src/globals.h | 2 ++
src/src/readconf.c | 1 +
test/confs/0624 | 1 +
test/confs/{0624 => 0625} | 7 ++++---
test/log/0625 | 21 +++++++++++++++++++++
test/rejectlog/0625 | 5 +++++
test/scripts/0000-Basic/0625 | 10 ++++++++++
12 files changed, 93 insertions(+), 11 deletions(-)
diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index dfbd7a4..b462f67 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -14714,6 +14714,7 @@ listed in more than one group.
.row &%notifier_socket%& "override compiled-in value"
.row &%pid_file_path%& "override compiled-in value"
.row &%queue_run_max%& "maximum simultaneous queue runners"
+.row &%smtp_backlog_monitor%& "level to log listen baclog"
.endtable
@@ -17732,6 +17733,14 @@ messages, it is also used as the default for HELO commands in callout
verification if there is no remote transport from which to obtain a
&%helo_data%& value.
+.option smtp_backlog_monitor main integer 0
+.cindex "connection backlog" monitoring
+If this option is set to greater than zero, and the backlog of available
+TCP connections on a socket listening for SMTP is larger than it, a line
+is logged giving the value and the socket address and port.
+The value is retrived jsut before an accept call.
+This facility is only available on Linux.
+
.option smtp_banner main string&!! "see below"
.cindex "SMTP" "welcome banner"
.cindex "banner for SMTP"
@@ -17762,7 +17771,7 @@ is zero). If there isn't enough space, a temporary error code is returned.
.option smtp_connect_backlog main integer 20
-.cindex "connection backlog"
+.cindex "connection backlog" "set maximum"
.cindex "SMTP" "connection backlog"
.cindex "backlog of connections"
This option specifies a maximum number of waiting SMTP connections. Exim passes
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index 0ac271e..c5a70da 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -51,6 +51,9 @@ Version 4.95
14. Log selector "queue_size_exclusive", enabled by default, to exclude the
time taken for reception from QT log elements.
+15. Main option "smtp_backlog_monitor", to set a level abve which listen
+ socket backlogs are logged.
+
Version 4.94
------------
diff --git a/doc/doc-txt/OptionLists.txt b/doc/doc-txt/OptionLists.txt
index 59be0a0..2f3435f 100644
--- a/doc/doc-txt/OptionLists.txt
+++ b/doc/doc-txt/OptionLists.txt
@@ -538,6 +538,7 @@ smtp_accept_queue integer 0 main
smtp_accept_queue_per_connection integer 10 main 2.03
smtp_accept_reserve integer 0 main
smtp_active_hostname string* unset main 4.33
+smtp_backlog_monitor integer 0 main 4.95
smtp_banner string* + main
smtp_check_spool_space boolean true main 2.10
smtp_connect_backlog integer 5 main
diff --git a/src/src/daemon.c b/src/src/daemon.c
index 626b435..2d8b223 100644
--- a/src/src/daemon.c
+++ b/src/src/daemon.c
@@ -396,12 +396,18 @@ if (pid == 0)
int save_debug_selector = debug_selector;
BOOL local_queue_only;
BOOL session_local_queue_only;
- #ifdef SA_NOCLDWAIT
+#ifdef SA_NOCLDWAIT
struct sigaction act;
- #endif
+#endif
smtp_accept_count++; /* So that it includes this process */
+ /* If the listen backlog was over the monitoring level, log it. */
+
+ if (smtp_listen_backlog > smtp_backlog_monitor)
+ log_write(0, LOG_MAIN, "listen backlog %d I=[%s]:%d",
+ smtp_listen_backlog, interface_address, interface_port);
+
/* May have been modified for the subprocess */
*log_selector = save_log_selector;
@@ -685,6 +691,7 @@ if (pid == 0)
(void)fclose(smtp_in);
(void)close(fileno(smtp_out));
(void)fclose(smtp_out);
+ smtp_in = smtp_out = NULL;
/* Don't ever molest the parent's SSL connection, but do clean up
the data structures if necessary. */
@@ -2493,12 +2500,31 @@ for (;;)
}
while (check_lsk < listen_socket_count)
{
- int sk = check_lsk++;
- if (FD_ISSET(listen_sockets[sk], &fds))
+ int lfd = listen_sockets[check_lsk++];
+ if (FD_ISSET(lfd, &fds))
{
- EXIM_SOCKLEN_T len = sizeof(accepted);
- accept_socket = accept(listen_sockets[sk],
- (struct sockaddr *)&accepted, &len);
+ EXIM_SOCKLEN_T alen = sizeof(accepted);
+ struct tcp_info ti;
+ socklen_t tlen = sizeof(ti);
+
+ /* If monitoring the backlog is wanted, grab for later logging */
+
+ smtp_listen_backlog = 0;
+#if defined(TCP_INFO)
+ if ( smtp_backlog_monitor > 0
+ && getsockopt(lfd, IPPROTO_TCP, TCP_INFO, &ti, &tlen) == 0)
+ {
+ DEBUG(D_interface) debug_printf("listen fd %d queue max %u curr %u\n",
+# ifdef EXIM_HAVE_TCPI_UNACKED
+ lfd, ti.tcpi_sacked, ti.tcpi_unacked);
+ smtp_listen_backlog = ti.tcpi_unacked;
+# elif defined(__FreeBSD__) /* This does not work. Investigate kernel sourcecode. */
+ lfd, ti.__tcpi_sacked, ti.__tcpi_unacked);
+ smtp_listen_backlog = ti.__tcpi_unacked;
+# endif
+ }
+#endif
+ accept_socket = accept(lfd, (struct sockaddr *)&accepted, &alen);
break;
}
}
diff --git a/src/src/globals.c b/src/src/globals.c
index e1837b6..ef7063d 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -1471,6 +1471,7 @@ int smtp_accept_queue = 0;
int smtp_accept_queue_per_connection = 10;
int smtp_accept_reserve = 0;
uschar *smtp_active_hostname = NULL;
+int smtp_backlog_monitor = 0;
uschar *smtp_banner = US"$smtp_active_hostname ESMTP "
"Exim $version_number $tod_full"
"\0<---------------Space to patch smtp_banner->";
@@ -1483,6 +1484,7 @@ int smtp_connect_backlog = 20;
double smtp_delay_mail = 0.0;
double smtp_delay_rcpt = 0.0;
FILE *smtp_in = NULL;
+int smtp_listen_backlog = 0;
int smtp_load_reserve = -1;
int smtp_mailcmd_count = 0;
FILE *smtp_out = NULL;
diff --git a/src/src/globals.h b/src/src/globals.h
index 4beb9d0..c7a2635 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -945,6 +945,7 @@ extern int smtp_accept_queue; /* Queue after so many connections */
extern int smtp_accept_queue_per_connection; /* Queue after so many msgs */
extern int smtp_accept_reserve; /* Reserve these SMTP connections */
extern uschar *smtp_active_hostname; /* Hostname for this message */
+extern int smtp_backlog_monitor; /* listen backlog level to log */
extern uschar *smtp_banner; /* Banner string (to be expanded) */
extern BOOL smtp_check_spool_space; /* TRUE to check SMTP SIZE value */
extern int smtp_ch_index; /* Index in smtp_connection_had */
@@ -959,6 +960,7 @@ extern BOOL smtp_enforce_sync; /* Enforce sync rules */
extern uschar *smtp_etrn_command; /* Command to run */
extern BOOL smtp_etrn_serialize; /* Only one at once */
extern FILE *smtp_in; /* Incoming SMTP input file */
+extern int smtp_listen_backlog; /* Current listener socket backlog, if monitored */
extern int smtp_load_reserve; /* Only from reserved if load > this */
extern int smtp_mailcmd_count; /* Count of MAIL commands */
extern int smtp_max_synprot_errors;/* Max syntax/protocol errors */
diff --git a/src/src/readconf.c b/src/src/readconf.c
index 8161333..6d7e7a1 100644
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -309,6 +309,7 @@ static optionlist optionlist_config[] = {
{ "smtp_accept_queue_per_connection", opt_int, {&smtp_accept_queue_per_connection} },
{ "smtp_accept_reserve", opt_int, {&smtp_accept_reserve} },
{ "smtp_active_hostname", opt_stringptr, {&raw_active_hostname} },
+ { "smtp_backlog_monitor", opt_int, {&smtp_backlog_monitor} },
{ "smtp_banner", opt_stringptr, {&smtp_banner} },
{ "smtp_check_spool_space", opt_bool, {&smtp_check_spool_space} },
{ "smtp_connect_backlog", opt_int, {&smtp_connect_backlog} },
diff --git a/test/confs/0624 b/test/confs/0624
index 2ffd0a1..70f0c20 100644
--- a/test/confs/0624
+++ b/test/confs/0624
@@ -34,6 +34,7 @@ smtp:
hosts = 127.0.0.1
port = ${if eq {c}{$local_part} {PORT_D2}{PORT_D}}
allow_localhost
+ hosts_try_fastopen =
max_rcpt = 1
# ----- Retry -----
diff --git a/test/confs/0624 b/test/confs/0625
similarity index 86%
copy from test/confs/0624
copy to test/confs/0625
index 2ffd0a1..ff200a1 100644
--- a/test/confs/0624
+++ b/test/confs/0625
@@ -1,13 +1,13 @@
-# Exim test configuration 0624
+# Exim test configuration 0625
.include DIR/aux-var/std_conf_prefix
-
# ----- Main settings -----
domainlist local_domains = test.ex
qualify_domain = test.ex
log_selector = +received_recipients +outgoing_port +millisec
+smtp_backlog_monitor = 1
smtp_accept_max_per_host = ${acl {delay}}10
remote_max_parallel = 3
@@ -32,8 +32,9 @@ begin transports
smtp:
driver = smtp
hosts = 127.0.0.1
- port = ${if eq {c}{$local_part} {PORT_D2}{PORT_D}}
+ port = PORT_D
allow_localhost
+ hosts_try_fastopen =
max_rcpt = 1
# ----- Retry -----
diff --git a/test/log/0625 b/test/log/0625
new file mode 100644
index 0000000..41dcfb4
--- /dev/null
+++ b/test/log/0625
@@ -0,0 +1,21 @@
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 <= CALLER@??? U=CALLER P=local S=sss for a@??? b@??? c@???
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 => a@??? R=r T=smtp H=127.0.0.1 [127.0.0.1]:PORT_D C="250 OK id=10HmaY-0005vi-00"
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 => b@??? R=r T=smtp H=127.0.0.1 [127.0.0.1]:PORT_D C="250 OK id=10HmaZ-0005vi-00"
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 => c@??? R=r T=smtp H=127.0.0.1 [127.0.0.1]:PORT_D C="250 OK id=10HmbA-0005vi-00"
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 Completed
+
+******** SERVER ********
+2017-07-30 18:51:05.712 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port PORT_D
+2017-07-30 18:51:05.712 H=localhost (the.local.host.name) [127.0.0.1] F=<CALLER@???> RCPT <a@???>: discarded by RCPT ACL
+2017-07-30 18:51:05.712 10HmaY-0005vi-00 <= CALLER@??? H=localhost (the.local.host.name) [127.0.0.1] P=esmtp S=sss id=E10HmaX-0005vi-00@???
+2017-07-30 18:51:05.712 10HmaY-0005vi-00 => blackhole (RCPT ACL discarded recipients)
+2017-07-30 18:51:05.712 10HmaY-0005vi-00 Completed
+2017-07-30 18:51:05.712 listen backlog 2 I=[127.0.0.1]:ppppp
+2017-07-30 18:51:05.712 H=localhost (the.local.host.name) [127.0.0.1] F=<CALLER@???> RCPT <b@???>: discarded by RCPT ACL
+2017-07-30 18:51:05.712 10HmaZ-0005vi-00 <= CALLER@??? H=localhost (the.local.host.name) [127.0.0.1] P=esmtp S=sss id=E10HmaX-0005vi-00@???
+2017-07-30 18:51:05.712 10HmaZ-0005vi-00 => blackhole (RCPT ACL discarded recipients)
+2017-07-30 18:51:05.712 10HmaZ-0005vi-00 Completed
+2017-07-30 18:51:05.712 H=localhost (the.local.host.name) [127.0.0.1] F=<CALLER@???> RCPT <c@???>: discarded by RCPT ACL
+2017-07-30 18:51:05.712 10HmbA-0005vi-00 <= CALLER@??? H=localhost (the.local.host.name) [127.0.0.1] P=esmtp S=sss id=E10HmaX-0005vi-00@???
+2017-07-30 18:51:05.712 10HmbA-0005vi-00 => blackhole (RCPT ACL discarded recipients)
+2017-07-30 18:51:05.712 10HmbA-0005vi-00 Completed
diff --git a/test/rejectlog/0625 b/test/rejectlog/0625
new file mode 100644
index 0000000..cfb1500
--- /dev/null
+++ b/test/rejectlog/0625
@@ -0,0 +1,5 @@
+
+******** SERVER ********
+2017-07-30 18:51:05.712 H=localhost (the.local.host.name) [127.0.0.1] F=<CALLER@???> RCPT <a@???>: discarded by RCPT ACL
+2017-07-30 18:51:05.712 H=localhost (the.local.host.name) [127.0.0.1] F=<CALLER@???> RCPT <b@???>: discarded by RCPT ACL
+2017-07-30 18:51:05.712 H=localhost (the.local.host.name) [127.0.0.1] F=<CALLER@???> RCPT <c@???>: discarded by RCPT ACL
diff --git a/test/scripts/0000-Basic/0625 b/test/scripts/0000-Basic/0625
new file mode 100644
index 0000000..b39a1cb
--- /dev/null
+++ b/test/scripts/0000-Basic/0625
@@ -0,0 +1,10 @@
+# queued connections on listener socket
+#
+exim -bd -DSERVER=server -oX PORT_D
+****
+exim a@??? b@??? c@???
+Subject: test mail
+****
+#
+sleep 8
+killdaemon
