openwrtv3/package/busybox/patches/610-syslog-remote-retry-connection.patch

--- a/sysklogd/syslogd.c
+++ b/sysklogd/syslogd.c
@@ -98,6 +98,8 @@ struct globals {
 	GLOBALS
 
 #if ENABLE_FEATURE_REMOTE_LOG
+	len_and_sockaddr *remoteAddr;
+	int remoteFD;
 	llist_t *remoteHosts;
 #endif
 #if ENABLE_FEATURE_IPC_SYSLOG
@@ -554,6 +556,7 @@ static void do_syslogd(void) NORETURN;
 static void do_syslogd(void)
 {
 	int sock_fd;
+	int send_err = 0;
 #if ENABLE_FEATURE_REMOTE_LOG
 	llist_t *item;
 #endif
@@ -637,10 +640,23 @@ static void do_syslogd(void)
 					continue;
 			}
 			/* Send message to remote logger, ignore possible error */
-			/* TODO: on some errors, close and set G.remoteFD to -1
-			 * so that DNS resolution and connect is retried? */
-			sendto(rh->remoteFD, recvbuf, sz+1, MSG_DONTWAIT,
-				&(rh->remoteAddr->u.sa), rh->remoteAddr->len);
+			if (sendto(rh->remoteFD, recvbuf, sz+1, MSG_DONTWAIT,
+				&G.remoteAddr->u.sa, G.remoteAddr->len)  == -1 ) {
+				send_err = errno;
+			}
+
+			/* On some errors, close and set G.remoteFD to -1
+			 * so that DNS resolution and connect is retried */
+			switch (send_err) {
+				case ECONNRESET:
+				case EDESTADDRREQ:
+				case EISCONN:
+				case ENOTCONN:
+				case EPIPE:
+					close(G.remoteFD);
+					G.remoteFD = -1;
+					break;
+			}
 		}
 #endif
 		if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {