server: use libwebsockets's built-in ping-pong

html/js/app.js

@@ -147,7 +147,7 @@ var terminalContainer = document.getElementById('terminal-container'),
     textEncoder = new TextEncoder(),
     authToken = (typeof tty_auth_token !== 'undefined') ? tty_auth_token : null,
     autoReconnect = -1,
-    term, pingTimer, title, wsError;
+    term, title, wsError;
 
 var openWs = function() {
     var ws = new WebSocket(url, ['tty']);
@@ -198,9 +198,6 @@ var openWs = function() {
         console.log('Websocket connection opened');
         wsError = false;
         sendMessage(JSON.stringify({AuthToken: authToken}));
-        pingTimer = setInterval(function() {
-            sendMessage('1');
-        }, 30 * 1000);
 
         if (typeof term !== 'undefined') {
             term.destroy();
@@ -234,7 +231,7 @@ var openWs = function() {
 
         term.on('resize', function(size) {
             if (ws.readyState === WebSocket.OPEN) {
-                sendMessage('2' + JSON.stringify({columns: size.cols, rows: size.rows}));
+                sendMessage('1' + JSON.stringify({columns: size.cols, rows: size.rows}));
             }
             setTimeout(function() {
                 term.showOverlay(size.cols + 'x' + size.rows);
@@ -276,20 +273,18 @@ var openWs = function() {
             case '0':
                 zsentry.consume(data);
                 break;
-            case '1': // pong
+            case '1':
-                break;
-            case '2':
                 title = textDecoder.decode(data);
                 document.title = title;
                 break;
-            case '3':
+            case '2':
                 var preferences = JSON.parse(textDecoder.decode(data));
                 Object.keys(preferences).forEach(function(key) {
                     console.log('Setting ' + key + ': ' +  preferences[key]);
                     term.setOption(key, preferences[key]);
                 });
                 break;
-            case '4':
+            case '3':
                 autoReconnect = JSON.parse(textDecoder.decode(data));
                 console.log('Enabling reconnect: ' + autoReconnect + ' seconds');
                 break;
@@ -309,7 +304,6 @@ var openWs = function() {
             }
         }
         window.removeEventListener('beforeunload', unloadCallback);
-        clearInterval(pingTimer);
         // 1000: CLOSE_NORMAL
         if (event.code !== 1000 && autoReconnect > 0) {
             setTimeout(openWs, autoReconnect * 1000);

src/protocol.c

@@ -273,15 +273,14 @@ callback_tty(struct lws *wsi, enum lws_callback_reasons reason,
 
         case LWS_CALLBACK_RECEIVE:
             if (client->buffer == NULL) {
-                client->buffer = xmalloc(len + 1);
+                client->buffer = xmalloc(len);
                 client->len = len;
                 memcpy(client->buffer, in, len);
             } else {
-                client->buffer = xrealloc(client->buffer, client->len + len + 1);
+                client->buffer = xrealloc(client->buffer, client->len + len);
                 memcpy(client->buffer + client->len, in, len);
                 client->len += len;
             }
-            client->buffer[client->len] = '\0';
 
             const char command = client->buffer[0];
 
@@ -302,24 +301,13 @@ callback_tty(struct lws *wsi, enum lws_callback_reasons reason,
                         break;
                     if (server->readonly)
                         return 0;
-                    if (write(client->pty, client->buffer + 1, client->len - 1) < client->len - 1) {
+                    if (write(client->pty, client->buffer + 1, client->len - 1) == -1) {
-                        lwsl_err("write INPUT to pty\n");
+                        lwsl_err("write INPUT to pty: %d (%s)\n", errno, strerror(errno));
                         tty_client_remove(client);
                         lws_close_reason(wsi, LWS_CLOSE_STATUS_UNEXPECTED_CONDITION, NULL, 0);
                         return -1;
                     }
                     break;
-                case PING:
-                    {
-                        unsigned char c = PONG;
-                        if (lws_write(wsi, &c, 1, LWS_WRITE_BINARY) != 1) {
-                            lwsl_err("send PONG\n");
-                            tty_client_remove(client);
-                            lws_close_reason(wsi, LWS_CLOSE_STATUS_UNEXPECTED_CONDITION, NULL, 0);
-                            return -1;
-                        }
-                    }
-                    break;
                 case RESIZE_TERMINAL:
                     if (parse_window_size(client->buffer + 1, &client->size) && client->pty > 0) {
                         if (ioctl(client->pty, TIOCSWINSZ, &client->size) == -1) {

src/server.c

@@ -218,7 +218,6 @@ main(int argc, char **argv) {
     info.max_http_header_pool = 16;
     info.options = LWS_SERVER_OPTION_VALIDATE_UTF8;
     info.extensions = extensions;
-    info.timeout_secs = 5;
 
     int debug_level = LLL_ERR | LLL_WARN | LLL_NOTICE;
     char iface[128] = "";
@@ -369,6 +368,9 @@ main(int argc, char **argv) {
     char server_hdr[128] = "";
     sprintf(server_hdr, "ttyd/%s (libwebsockets/%s)", TTYD_VERSION, LWS_LIBRARY_VERSION);
     info.server_string = server_hdr;
+#if LWS_LIBRARY_VERSION_MINOR >= 1
+    info.ws_ping_pong_interval = 5;
+#endif
 #endif
 
     if (strlen(iface) > 0) {

src/server.h

@@ -52,16 +52,14 @@
 
 // client message
 #define INPUT '0'
-#define PING '1'
+#define RESIZE_TERMINAL '1'
-#define RESIZE_TERMINAL '2'
 #define JSON_DATA '{'
 
 // server message
 #define OUTPUT '0'
-#define PONG '1'
+#define SET_WINDOW_TITLE '1'
-#define SET_WINDOW_TITLE '2'
+#define SET_PREFERENCES '2'
-#define SET_PREFERENCES '3'
+#define SET_RECONNECT '3'
-#define SET_RECONNECT '4'
 
 // websocket url path
 #define WS_PATH "/ws"