TCP keepalive setting support

src/conn.c

@@ -175,6 +175,26 @@ xmpp_conn_t *xmpp_conn_clone(xmpp_conn_t * const conn)
     return conn;
 }
 
+/** Set TCP keepalive parameters
+ *  Turn on TCP keepalive and set timeout and interval. Zero timeout
+ *  disables TCP keepalives.
+ *
+ *  @param conn a Strophe connection object
+ *  @param timeout TCP keepalive timeout in seconds
+ *  @param interval TCP keepalive interval in seconds
+ *
+ *  @ingroup Connections
+ */
+void xmpp_conn_set_keepalive(xmpp_conn_t * const conn, int timeout, int interval)
+{
+    int ret;
+    ret = sock_set_keepalive(conn->sock, timeout, interval);
+    if (ret < 0) {
+        xmpp_error(conn->ctx, "xmpp", "Setting TCP keepalive (%d,%d) error: %d",
+                   timeout, interval, sock_error());
+    }
+}
+
 /** Release a Strophe connection object.
  *  Decrement the reference count by one for a connection, freeing the
  *  connection object if the count reaches 0.

src/sock.c

@@ -22,11 +22,13 @@
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <Iphlpapi.h>
+#include <Mstcpip.h>    /* tcp_keepalive */
 #else
 #include <errno.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <netdb.h>
 #include <fcntl.h>
 #endif
@@ -108,6 +110,42 @@ sock_t sock_connect(const char * const host, const unsigned short port)
     return sock;
 }
 
+int sock_set_keepalive(const sock_t sock, int timeout, int interval)
+{
+    int ret;
+    int optval = (timeout && interval) ? 1 : 0;
+
+#ifdef _WIN32
+    struct tcp_keepalive ka;
+    DWORD dw = 0;
+
+    ka.onoff = optval;
+    ka.keepalivetime = timeout * 1000;
+    ka.keepaliveinterval = interval * 1000;
+    ret = WSAIoctl(sock, SIO_KEEPALIVE_VALS, &ka, sizeof(ka), NULL, 0, &dw, NULL, NULL);
+#else
+    ret = setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &optval, sizeof(optval));
+    if (ret < 0)
+        return ret;
+
+    if (optval) {
+        /* it's not possible to set keepalive count in Windows, so just use some
+         * acceptable value for UNIX to keep things work the same */
+        optval = 5;
+        ret = setsockopt(sock, SOL_TCP, TCP_KEEPCNT, &optval, sizeof(optval));
+        if (ret < 0)
+            return ret;
+        ret = setsockopt(sock, SOL_TCP, TCP_KEEPIDLE, &timeout, sizeof(timeout));
+        if (ret < 0)
+            return ret;
+        ret = setsockopt(sock, SOL_TCP, TCP_KEEPINTVL, &interval, sizeof(interval));
+        if (ret < 0)
+            return ret;
+    }
+#endif
+    return ret;
+}
+
 int sock_close(const sock_t sock)
 {
 #ifdef _WIN32

src/sock.h

@@ -40,5 +40,6 @@ int sock_write(const sock_t sock, const void * const buff, const size_t len);
 int sock_is_recoverable(const int error);
 /* checks for an error after connect, return 0 if connect successful */
 int sock_connect_error(const sock_t sock);
+int sock_set_keepalive(const sock_t sock, int timeout, int interval);
 
 #endif /* __LIBSTROPHE_SOCK_H__ */

strophe.h

@@ -222,6 +222,7 @@ void xmpp_conn_set_pass(xmpp_conn_t * const conn, const char * const pass);
 xmpp_ctx_t* xmpp_conn_get_context(xmpp_conn_t * const conn);
 void xmpp_conn_disable_tls(xmpp_conn_t * const conn);
 int xmpp_conn_is_secured(xmpp_conn_t * const conn);
+void xmpp_conn_set_keepalive(xmpp_conn_t * const conn, int timeout, int interval);
 
 int xmpp_connect_client(xmpp_conn_t * const conn, 
 			  const char * const altdomain,