[systemd-devel] [PATCH 1/3] socket: Add Support for TCP keep alive variables

Susant Sahani susant at redhat.com
Tue Jul 29 10:40:07 PDT 2014


The tcp keep alive variables now can be configured via conf
parameter. Follwing variables are now supported by this patch.

tcp_keepalive_intvl: The number of seconds between TCP keep-alive probes

tcp_keepalive_probes: The maximum number of TCP keep-alive probes to
send before giving up and killing the connection if no response is
obtained from the other end.

tcp_keepalive_time: The number of seconds a connection needs to be
idle before TCP begins sending out keep-alive probes.
---
 man/systemd.socket.xml                | 36 +++++++++++++++++++++++++++++++++++
 src/core/dbus-socket.c                |  3 +++
 src/core/load-fragment-gperf.gperf.m4 |  3 +++
 src/core/socket.c                     | 33 ++++++++++++++++++++++++++++++++
 src/core/socket.h                     |  3 +++
 5 files changed, 78 insertions(+)

diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml
index 09a7311..6dbcc81 100644
--- a/man/systemd.socket.xml
+++ b/man/systemd.socket.xml
@@ -488,6 +488,42 @@
                         </varlistentry>
 
                         <varlistentry>
+                          <term><varname>KeepAliveTime=</varname></term>
+                          <listitem><para>Takes time (in seconds) as argument . The connection needs to remain
+                          idle before TCP starts sending keepalive probes. This controls the TCP_KEEPIDLE
+                          socket option (see
+                          <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+                          and the <ulink
+                          url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
+                          Keepalive HOWTO</ulink> for details.)
+                          Defaults  value is 7200 seconds (2 hours).</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                          <term><varname>KeepAliveInterval=</varname></term>
+                          <listitem><para>Takes time (in seconds) as argument between individual keepalive probes,
+                          if the socket option SO_KEEPALIVE has  been set on this socket seconds as argument.
+                          This controls the TCP_KEEPINTVL socket option (see
+                          <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+                          and the <ulink
+                          url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
+                          Keepalive HOWTO</ulink> for details.)
+                          Defaults  value is 75 seconds.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                          <term><varname>KeepAliveProbes=</varname></term>
+                          <listitem><para>Takes interger as argument. It's the number of unacknowledged probes to
+                          send before considering the connection dead and notifying the application layer.
+                          This controls the TCP_KEEPCNT socket option (see
+                          <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+                          and the <ulink
+                          url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
+                          Keepalive HOWTO</ulink> for details.)
+                          Defaults  value is 9.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
                                 <term><varname>Priority=</varname></term>
                                 <listitem><para>Takes an integer
                                 argument controlling the priority for
diff --git a/src/core/dbus-socket.c b/src/core/dbus-socket.c
index ad135a1..348afbd 100644
--- a/src/core/dbus-socket.c
+++ b/src/core/dbus-socket.c
@@ -97,6 +97,9 @@ const sd_bus_vtable bus_socket_vtable[] = {
         SD_BUS_PROPERTY("DirectoryMode", "u", bus_property_get_mode, offsetof(Socket, directory_mode), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("Accept", "b", bus_property_get_bool, offsetof(Socket, accept), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("KeepAlive", "b", bus_property_get_bool, offsetof(Socket, keep_alive), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("KeepAliveTime", "t", bus_property_get_usec, offsetof(Socket, keep_alive_time), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("KeepAliveInterval", "t", bus_property_get_usec, offsetof(Socket, keep_alive_interval), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("KeepAliveProbes", "i", bus_property_get_int, offsetof(Socket, keep_alive_cnt), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("Priority", "i", bus_property_get_int, offsetof(Socket, priority), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("ReceiveBuffer", "t", bus_property_get_size, offsetof(Socket, receive_buffer), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("SendBuffer", "t", bus_property_get_size, offsetof(Socket, send_buffer), SD_BUS_VTABLE_PROPERTY_CONST),
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index d70f9ee..af9f9cc 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -231,6 +231,9 @@ Socket.DirectoryMode,            config_parse_mode,                  0,
 Socket.Accept,                   config_parse_bool,                  0,                             offsetof(Socket, accept)
 Socket.MaxConnections,           config_parse_unsigned,              0,                             offsetof(Socket, max_connections)
 Socket.KeepAlive,                config_parse_bool,                  0,                             offsetof(Socket, keep_alive)
+Socket.KeepAliveTime,            config_parse_sec,                   0,                             offsetof(Socket, keep_alive_time)
+Socket.KeepAliveInterval,        config_parse_sec,                   0,                             offsetof(Socket, keep_alive_interval)
+Socket.KeepAliveProbes,          config_parse_unsigned,              0,                             offsetof(Socket, keep_alive_cnt)
 Socket.Priority,                 config_parse_int,                   0,                             offsetof(Socket, priority)
 Socket.ReceiveBuffer,            config_parse_iec_size,              0,                             offsetof(Socket, receive_buffer)
 Socket.SendBuffer,               config_parse_iec_size,              0,                             offsetof(Socket, send_buffer)
diff --git a/src/core/socket.c b/src/core/socket.c
index 646887d..c770fe2 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -593,6 +593,21 @@ static void socket_dump(Unit *u, FILE *f, const char *prefix) {
                         prefix, strna(s->user),
                         prefix, strna(s->group));
 
+        if(s->keep_alive_time)
+                fprintf(f,
+                        "%sKeepAliveTime: %lo\n",
+                        prefix, s->keep_alive_time / USEC_PER_SEC);
+
+        if(s->keep_alive_interval)
+                fprintf(f,
+                        "%sKeepAliveInterval: %lo\n",
+                        prefix, s->keep_alive_interval / USEC_PER_SEC);
+
+        if(s->keep_alive_cnt)
+                fprintf(f,
+                        "%sKeepAliveProbes: %u\n",
+                        prefix, s->keep_alive_cnt);
+
         LIST_FOREACH(port, p, s->ports) {
 
                 if (p->type == SOCKET_SOCKET) {
@@ -790,6 +805,24 @@ static void socket_apply_socket_options(Socket *s, int fd) {
                         log_warning_unit(UNIT(s)->id, "SO_KEEPALIVE failed: %m");
         }
 
+        if (s->keep_alive_time) {
+                int value = s->keep_alive_time / USEC_PER_SEC;
+                if (setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, &value, sizeof(value)) < 0)
+                        log_warning_unit(UNIT(s)->id, "TCP_KEEPIDLE failed: %m");
+        }
+
+        if (s->keep_alive_interval) {
+                int value =  s->keep_alive_interval / USEC_PER_SEC;
+                if (setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, &value, sizeof(value)) < 0)
+                        log_warning_unit(UNIT(s)->id, "TCP_KEEPINTVL failed: %m");
+        }
+
+        if (s->keep_alive_cnt) {
+                int value = s->keep_alive_cnt;
+                if (setsockopt(fd, SOL_SOCKET, TCP_KEEPCNT, &value, sizeof(value)) < 0)
+                        log_warning_unit(UNIT(s)->id, "TCP_KEEPCNT failed: %m");
+        }
+
         if (s->broadcast) {
                 int one = 1;
                 if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one)) < 0)
diff --git a/src/core/socket.h b/src/core/socket.h
index 814a3bf..aa300e5 100644
--- a/src/core/socket.h
+++ b/src/core/socket.h
@@ -102,6 +102,8 @@ struct Socket {
 
         unsigned backlog;
         usec_t timeout_usec;
+        usec_t keep_alive_time;
+        usec_t keep_alive_interval;
 
         ExecCommand* exec_command[_SOCKET_EXEC_COMMAND_MAX];
         ExecContext exec_context;
@@ -145,6 +147,7 @@ struct Socket {
 
         int priority;
         int mark;
+        int keep_alive_cnt;
         size_t receive_buffer;
         size_t send_buffer;
         int ip_tos;
-- 
1.9.3



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