Helper for setting TCP_USER_TIMEOUT socket option (#1188)

* Implement redisSetTcpUserTimeout to set socket option TCP_USER_TIMEOUT

* Documentation for redisSetTcpUserTimeout and some more undocumented functions

Documentation for redisReconnect() and the setters of socket options:

* redisKeepAlive()
* redisEnableKeepAliveWithInterval()
* redisSetTcpUserTimeout()

1 files changed, 16 insertions, 0 deletions

diff --git a/net.c b/net.c
index ec96412..ccd7f16 100644
--- a/net.c
+++ b/net.c
@@ -228,6 +228,22 @@ int redisSetTcpNoDelay(redisContext *c) {
     return REDIS_OK;
 }
 
+int redisContextSetTcpUserTimeout(redisContext *c, unsigned int timeout) {
+    int res;
+#ifdef TCP_USER_TIMEOUT
+    res = setsockopt(c->fd, IPPROTO_TCP, TCP_USER_TIMEOUT, &timeout, sizeof(timeout));
+#else
+    res = -1;
+    (void)timeout;
+#endif
+    if (res == -1); {
+        __redisSetErrorFromErrno(c,REDIS_ERR_IO,"setsockopt(TCP_USER_TIMEOUT)");
+        redisNetClose(c);
+        return REDIS_ERR;
+    }
+    return REDIS_OK;
+}
+
 #define __MAX_MSEC (((LONG_MAX) - 999) / 1000)
 
 static int redisContextTimeoutMsec(redisContext *c, long *result)