io/channel-websock: treat 'binary' and no sub-protocol as the same

noVNC doesn't use 'binary' protocol by default after
commit c912230309806aacbae4295faf7ad6406da97617.

It will cause qemu return 400 when handshaking.

To overcome this problem and remain compatibility of
older noVNC client.

We treat 'binary' and no sub-protocol as the same
so that we can support different version of noVNC
client.

Tested on noVNC before c912230 and after c912230.

Buglink: https://bugs.launchpad.net/qemu/+bug/1849644

Signed-off-by: Yu-Chen Lin <npes87184@gmail.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

io/channel-websock.c

@@ -49,13 +49,20 @@
     "Server: QEMU VNC\r\n"                       \
     "Date: %s\r\n"
 
+#define QIO_CHANNEL_WEBSOCK_HANDSHAKE_WITH_PROTO_RES_OK \
+    "HTTP/1.1 101 Switching Protocols\r\n"              \
+    QIO_CHANNEL_WEBSOCK_HANDSHAKE_RES_COMMON            \
+    "Upgrade: websocket\r\n"                            \
+    "Connection: Upgrade\r\n"                           \
+    "Sec-WebSocket-Accept: %s\r\n"                      \
+    "Sec-WebSocket-Protocol: binary\r\n"                \
+    "\r\n"
 #define QIO_CHANNEL_WEBSOCK_HANDSHAKE_RES_OK    \
     "HTTP/1.1 101 Switching Protocols\r\n"      \
     QIO_CHANNEL_WEBSOCK_HANDSHAKE_RES_COMMON    \
     "Upgrade: websocket\r\n"                    \
     "Connection: Upgrade\r\n"                   \
     "Sec-WebSocket-Accept: %s\r\n"              \
-    "Sec-WebSocket-Protocol: binary\r\n"        \
     "\r\n"
 #define QIO_CHANNEL_WEBSOCK_HANDSHAKE_RES_NOT_FOUND \
     "HTTP/1.1 404 Not Found\r\n"                    \
@@ -336,6 +343,7 @@ qio_channel_websock_find_header(QIOChannelWebsockHTTPHeader *hdrs,
 
 static void qio_channel_websock_handshake_send_res_ok(QIOChannelWebsock *ioc,
                                                       const char *key,
+                                                      const bool use_protocols,
                                                       Error **errp)
 {
     char combined_key[QIO_CHANNEL_WEBSOCK_CLIENT_KEY_LEN +
@@ -361,8 +369,14 @@ static void qio_channel_websock_handshake_send_res_ok(QIOChannelWebsock *ioc,
     }
 
     date = qio_channel_websock_date_str();
-    qio_channel_websock_handshake_send_res(
-        ioc, QIO_CHANNEL_WEBSOCK_HANDSHAKE_RES_OK, date, accept);
+    if (use_protocols) {
+            qio_channel_websock_handshake_send_res(
+                ioc, QIO_CHANNEL_WEBSOCK_HANDSHAKE_WITH_PROTO_RES_OK,
+                date, accept);
+    } else {
+            qio_channel_websock_handshake_send_res(
+                ioc, QIO_CHANNEL_WEBSOCK_HANDSHAKE_RES_OK, date, accept);
+    }
 
     g_free(date);
     g_free(accept);
@@ -387,10 +401,6 @@ static void qio_channel_websock_handshake_process(QIOChannelWebsock *ioc,
 
     protocols = qio_channel_websock_find_header(
         hdrs, nhdrs, QIO_CHANNEL_WEBSOCK_HEADER_PROTOCOL);
-    if (!protocols) {
-        error_setg(errp, "Missing websocket protocol header data");
-        goto bad_request;
-    }
 
     version = qio_channel_websock_find_header(
         hdrs, nhdrs, QIO_CHANNEL_WEBSOCK_HEADER_VERSION);
@@ -430,10 +440,12 @@ static void qio_channel_websock_handshake_process(QIOChannelWebsock *ioc,
     trace_qio_channel_websock_http_request(ioc, protocols, version,
                                            host, connection, upgrade, key);
 
-    if (!g_strrstr(protocols, QIO_CHANNEL_WEBSOCK_PROTOCOL_BINARY)) {
-        error_setg(errp, "No '%s' protocol is supported by client '%s'",
-                   QIO_CHANNEL_WEBSOCK_PROTOCOL_BINARY, protocols);
-        goto bad_request;
+    if (protocols) {
+            if (!g_strrstr(protocols, QIO_CHANNEL_WEBSOCK_PROTOCOL_BINARY)) {
+                error_setg(errp, "No '%s' protocol is supported by client '%s'",
+                           QIO_CHANNEL_WEBSOCK_PROTOCOL_BINARY, protocols);
+                goto bad_request;
+            }
     }
 
     if (!g_str_equal(version, QIO_CHANNEL_WEBSOCK_SUPPORTED_VERSION)) {
@@ -467,7 +479,7 @@ static void qio_channel_websock_handshake_process(QIOChannelWebsock *ioc,
         goto bad_request;
     }
 
-    qio_channel_websock_handshake_send_res_ok(ioc, key, errp);
+    qio_channel_websock_handshake_send_res_ok(ioc, key, !!protocols, errp);
     return;
 
  bad_request: