when sslh-fork accept() fails with some errors, retry accept instead of dying

sslh-fork.c

@@ -178,6 +178,25 @@ void tcp_listener(struct listen_endpoint* endpoint, int num_endpoints, int activ
     while (1) {
         in_socket = accept(endpoint[active_endpoint].socketfd, 0, 0);
         CHECK_RES_RETURN(in_socket, "accept", /*void*/ );
+        if (in_socket == -1) {
+            print_message(msg_system_error, "%s:%d:%s:%d:%s\n", 
+                          __FILE__, __LINE__, "accept", errno, strerror(errno));
+            switch(in_socket) {
+            case ENETDOWN:  /* accept(2) cites all these errnos as "you should retry" */
+            case EPROTO:
+            case ENOPROTOOPT:
+            case EHOSTDOWN:
+            case ENONET:
+            case EHOSTUNREACH:
+            case EOPNOTSUPP:
+            case ENETUNREACH:
+            case ECONNABORTED:
+                continue;
+
+            default:  /* Otherwise, it's something wrong in our parameters, we fail */
+                return;
+            }
+        }
         print_message(msg_fd, "accepted fd %d\n", in_socket);
 
         switch(fork()) {