From f023e47b9dac5be1d76013a4f74c322f6c520f2a Mon Sep 17 00:00:00 2001
From: Ari Johnson <ari@cobramush.org>
Date: Tue, 20 Feb 2007 19:39:22 +0000
Subject: [PATCH] Added keepalive_timeout configuration option; fixed
 SO_KEEPALIVE

---
 game/mushcnf.dst | 11 ++++++++++-
 hdrs/conf.h      |  1 +
 src/conf.c       |  3 +++
 src/mysocket.c   | 20 ++++++++++++++------
 4 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/game/mushcnf.dst b/game/mushcnf.dst
index 1f791b7..17a83b6 100644
--- a/game/mushcnf.dst
+++ b/game/mushcnf.dst
@@ -217,10 +217,19 @@ idle_timeout	0m
 # If you don't want a timeout, set it to 0.
 unconnected_idle_timeout	5m
 
-
 # how many seconds till we consider someone idled?
 idle_time	30m
 
+# Many common home network routers will drop a connection if there's
+# been no activity for a few minutes; they tend to assume the web is
+# the internet, and don't deal well with persistant connections like
+# mushes use. This option will make the server automatically send a
+# 'Are you still there?' query every few minutes to keep the
+# connection active.
+# NOTE: This doesn't work on all OSes, but does on the most popular
+# ones for mush hosting such as linux.
+keepalive_timeout 5m
+
 # Should there be a limit on the number of logins the MUSH
 # can accept? If your operating system has a limited number of
 # file descriptors per process, you should set this to 
diff --git a/hdrs/conf.h b/hdrs/conf.h
index 2bbd23c..cdca180 100644
--- a/hdrs/conf.h
+++ b/hdrs/conf.h
@@ -133,6 +133,7 @@ struct options_table {
   int idle_timeout;	/**< Maximum idle time allowed, in minutes */
   int idle_time;	/** Time for the system to consider player 'idle' used in conjuntion with @AUNIDLE */
   int unconnected_idle_timeout;	/**< Maximum idle time for connections without dbrefs, in minutes */
+  int keepalive_timeout; /**< Number of seconds between TCP keepalive pings */
   int dump_interval;	/**< Interval between database dumps, in seconds */
   char dump_message[256]; /**< Message shown at start of nonforking dump */
   char dump_complete[256]; /**< Message shown at end of nonforking dump */
diff --git a/src/conf.c b/src/conf.c
index 9fb25a7..2d49958 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -291,6 +291,8 @@ COBRA_CONF conftable[] = {
   {"unconnected_idle_timeout", cf_time, &options.unconnected_idle_timeout,
    100000, 0, "limits"}
   ,
+  {"keepalive_timeout", cf_time, &options.keepalive_timeout, 10000, 0, "limits"}
+  ,
   {"whisper_loudness", cf_int, &options.whisper_loudness, 100, 0, "limits"}
   ,
   {"starting_quota", cf_int, &options.starting_quota, 10000, 0, "limits"}
@@ -1066,6 +1068,7 @@ conf_default_set(void)
   options.idle_timeout = 0;
   options.idle_time = 0;
   options.unconnected_idle_timeout = 300;
+  options.keepalive_timeout = 300;
   options.dump_interval = 3601;
   strcpy(options.dump_message,
 	 T("GAME: Dumping database. Game may freeze for a minute"));
diff --git a/src/mysocket.c b/src/mysocket.c
index ceab173..d361b97 100644
--- a/src/mysocket.c
+++ b/src/mysocket.c
@@ -354,7 +354,7 @@ make_nonblocking(int s)
 }
 
 
-
+#ifndef INFOSLAVE
 /** Enable TCP keepalive on the given socket if we can.
  * \param s socket.
  */
@@ -362,25 +362,33 @@ make_nonblocking(int s)
 void
 set_keepalive(int s __attribute__ ((__unused__)))
 {
-#ifdef CAN_KEEPALIVE
+#ifdef SO_KEEPALIVE
   int keepalive = 1;
-#ifdef CAN_KEEPIDLE
-  int keepidle = 900;
+#if defined(TCP_KEEPIDLE) || defined(TCP_KEEPALIVE)
+  int keepidle = options.keepalive_timeout;
 #endif
 
   /* enable TCP keepalive */
   if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE,
 		 (void *) &keepalive, sizeof(keepalive)) == -1)
     fprintf(stderr, "[%d] could not set SO_KEEPALIVE: errno %d", s, errno);
-#ifdef CAN_KEEPIDLE
+
+  /* And set the ping time to something reasonable instead of the
+     default 2 hours. Linux, NetBSD and o thers use TCP_KEEPIDLE to do
+     this. OS X and possibly others use TCP_KEEPALIVE. */
+#if defined(TCP_KEEPIDLE)
   if (setsockopt(s, IPPROTO_TCP, TCP_KEEPIDLE,
 		 (void *) &keepidle, sizeof(keepidle)) == -1)
+    fprintf(stderr, "[%d] could not set TCP_KEEPIDLE: errno %d", s, errno);
+#elif defined(TCP_KEEPALIVE)
+  if (setsockopt(s, IPPROTO_TCP, TCP_KEEPALIVE,
+		 (void *) &keepidle, sizeof(keepidle)) == -1)
     fprintf(stderr, "[%d] could not set TCP_KEEPALIVE: errno %d", s, errno);
 #endif
 #endif
   return;
 }
-
+#endif
 
 
 /** Connect a socket, possibly making it nonblocking first.
-- 
2.30.2