chardev: Add websocket support

New option "websocket" added to allow using WebSocket protocol for
chardev socket backend.
Example:
    -chardev socket,websocket,server,id=...

Signed-off-by: Julia Suvorova <jusual@mail.ru>
Message-Id: <20181018223501.21683-3-jusual@mail.ru>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

chardev/char-socket.c

@@ -26,6 +26,7 @@
 #include "chardev/char.h"
 #include "io/channel-socket.h"
 #include "io/channel-tls.h"
+#include "io/channel-websock.h"
 #include "io/net-listener.h"
 #include "qemu/error-report.h"
 #include "qemu/option.h"
@@ -68,6 +69,8 @@ typedef struct {
     GSource *telnet_source;
     TCPChardevTelnetInit *telnet_init;
 
+    bool is_websock;
+
     GSource *reconnect_timer;
     int64_t reconnect_time;
     bool connect_err_reported;
@@ -394,7 +397,7 @@ static const char *qemu_chr_socket_protocol(SocketChardev *s)
     if (s->is_telnet) {
         return "telnet";
     }
-    return "tcp";
+    return s->is_websock ? "websocket" : "tcp";
 }
 
 static char *qemu_chr_socket_address(SocketChardev *s, const char *prefix)
@@ -714,6 +717,41 @@ cont:
 }
 
 
+static void tcp_chr_websock_handshake(QIOTask *task, gpointer user_data)
+{
+    Chardev *chr = user_data;
+    SocketChardev *s = user_data;
+
+    if (qio_task_propagate_error(task, NULL)) {
+        tcp_chr_disconnect(chr);
+    } else {
+        if (s->do_telnetopt) {
+            tcp_chr_telnet_init(chr);
+        } else {
+            tcp_chr_connect(chr);
+        }
+    }
+}
+
+
+static void tcp_chr_websock_init(Chardev *chr)
+{
+    SocketChardev *s = SOCKET_CHARDEV(chr);
+    QIOChannelWebsock *wioc = NULL;
+    gchar *name;
+
+    wioc = qio_channel_websock_new_server(s->ioc);
+
+    name = g_strdup_printf("chardev-websocket-server-%s", chr->label);
+    qio_channel_set_name(QIO_CHANNEL(wioc), name);
+    g_free(name);
+    object_unref(OBJECT(s->ioc));
+    s->ioc = QIO_CHANNEL(wioc);
+
+    qio_channel_websock_handshake(wioc, tcp_chr_websock_handshake, chr, NULL);
+}
+
+
 static void tcp_chr_tls_handshake(QIOTask *task,
                                   gpointer user_data)
 {
@@ -723,7 +761,9 @@ static void tcp_chr_tls_handshake(QIOTask *task,
     if (qio_task_propagate_error(task, NULL)) {
         tcp_chr_disconnect(chr);
     } else {
-        if (s->do_telnetopt) {
+        if (s->is_websock) {
+            tcp_chr_websock_init(chr);
+        } else if (s->do_telnetopt) {
             tcp_chr_telnet_init(chr);
         } else {
             tcp_chr_connect(chr);
@@ -809,12 +849,12 @@ static int tcp_chr_new_client(Chardev *chr, QIOChannelSocket *sioc)
 
     if (s->tls_creds) {
         tcp_chr_tls_init(chr);
+    } else if (s->is_websock) {
+        tcp_chr_websock_init(chr);
+    } else if (s->do_telnetopt) {
+        tcp_chr_telnet_init(chr);
     } else {
-        if (s->do_telnetopt) {
+        tcp_chr_connect(chr);
-            tcp_chr_telnet_init(chr);
-        } else {
-            tcp_chr_connect(chr);
-        }
     }
 
     return 0;
@@ -959,13 +999,20 @@ static void qmp_chardev_open_socket(Chardev *chr,
     bool is_telnet      = sock->has_telnet  ? sock->telnet  : false;
     bool is_tn3270      = sock->has_tn3270  ? sock->tn3270  : false;
     bool is_waitconnect = sock->has_wait    ? sock->wait    : false;
+    bool is_websock     = sock->has_websocket ? sock->websocket : false;
     int64_t reconnect   = sock->has_reconnect ? sock->reconnect : 0;
     QIOChannelSocket *sioc = NULL;
     SocketAddress *addr;
 
+    if (!is_listen && is_websock) {
+        error_setg(errp, "%s", "Websocket client is not implemented");
+        goto error;
+    }
+
     s->is_listen = is_listen;
     s->is_telnet = is_telnet;
     s->is_tn3270 = is_tn3270;
+    s->is_websock = is_websock;
     s->do_nodelay = do_nodelay;
     if (sock->tls_creds) {
         Object *creds;
@@ -1076,6 +1123,7 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
     bool is_waitconnect = is_listen && qemu_opt_get_bool(opts, "wait", true);
     bool is_telnet      = qemu_opt_get_bool(opts, "telnet", false);
     bool is_tn3270      = qemu_opt_get_bool(opts, "tn3270", false);
+    bool is_websock     = qemu_opt_get_bool(opts, "websocket", false);
     bool do_nodelay     = !qemu_opt_get_bool(opts, "delay", true);
     int64_t reconnect   = qemu_opt_get_number(opts, "reconnect", 0);
     const char *path = qemu_opt_get(opts, "path");
@@ -1124,6 +1172,8 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
     sock->telnet = is_telnet;
     sock->has_tn3270 = true;
     sock->tn3270 = is_tn3270;
+    sock->has_websocket = true;
+    sock->websocket = is_websock;
     sock->has_wait = true;
     sock->wait = is_waitconnect;
     sock->has_reconnect = qemu_opt_find(opts, "reconnect");

chardev/char.c

@@ -409,7 +409,8 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename,
     }
     if (strstart(filename, "tcp:", &p) ||
         strstart(filename, "telnet:", &p) ||
-        strstart(filename, "tn3270:", &p)) {
+        strstart(filename, "tn3270:", &p) ||
+        strstart(filename, "websocket:", &p)) {
         if (sscanf(p, "%64[^:]:%32[^,]%n", host, port, &pos) < 2) {
             host[0] = 0;
             if (sscanf(p, ":%32[^,]%n", port, &pos) < 1)
@@ -429,6 +430,8 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename,
             qemu_opt_set(opts, "telnet", "on", &error_abort);
         } else if (strstart(filename, "tn3270:", &p)) {
             qemu_opt_set(opts, "tn3270", "on", &error_abort);
+        } else if (strstart(filename, "websocket:", &p)) {
+            qemu_opt_set(opts, "websocket", "on", &error_abort);
         }
         return opts;
     }
@@ -860,6 +863,9 @@ QemuOptsList qemu_chardev_opts = {
         },{
             .name = "tls-creds",
             .type = QEMU_OPT_STRING,
+        },{
+            .name = "websocket",
+            .type = QEMU_OPT_BOOL,
         },{
             .name = "width",
             .type = QEMU_OPT_NUMBER,

qapi/char.json

@@ -251,6 +251,8 @@
 #          sockets (default: false)
 # @tn3270: enable tn3270 protocol on server
 #          sockets (default: false) (Since: 2.10)
+# @websocket: enable websocket protocol on server
+#           sockets (default: false) (Since: 3.1)
 # @reconnect: For a client socket, if a socket is disconnected,
 #          then attempt a reconnect after the given number of seconds.
 #          Setting this to zero disables this function. (default: 0)
@@ -265,6 +267,7 @@
                                      '*nodelay'   : 'bool',
                                      '*telnet'    : 'bool',
                                      '*tn3270'    : 'bool',
+                                     '*websocket' : 'bool',
                                      '*reconnect' : 'int' },
   'base': 'ChardevCommon' }
 

qemu-options.hx

@@ -2414,9 +2414,9 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
     "-chardev help\n"
     "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
     "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
-    "         [,server][,nowait][,telnet][,reconnect=seconds][,mux=on|off]\n"
+    "         [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
     "         [,logfile=PATH][,logappend=on|off][,tls-creds=ID] (tcp)\n"
-    "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,reconnect=seconds]\n"
+    "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
     "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
     "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
     "         [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
@@ -2544,7 +2544,7 @@ The available backends are:
 A void device. This device will not emit any data, and will drop any data it
 receives. The null backend does not take any options.
 
-@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,reconnect=@var{seconds}][,tls-creds=@var{id}]
+@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}]
 
 Create a two-way stream socket, which can be either a TCP or a unix socket. A
 unix socket will be created if @option{path} is specified. Behaviour is
@@ -2558,6 +2558,9 @@ connect to a listening socket.
 @option{telnet} specifies that traffic on the socket should interpret telnet
 escape sequences.
 
+@option{websocket} specifies that the socket uses WebSocket protocol for
+communication.
+
 @option{reconnect} sets the timeout for reconnecting on non-server sockets when
 the remote end goes away.  qemu will delay this many seconds and then attempt
 to reconnect.  Zero disables reconnecting, and is the default.
@@ -3106,6 +3109,10 @@ MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
 sequence.  Typically in unix telnet you do it with Control-] and then
 type "send break" followed by pressing the enter key.
 
+@item websocket:@var{host}:@var{port},server[,nowait][,nodelay]
+The WebSocket protocol is used instead of raw tcp socket. The port acts as
+a WebSocket server. Client mode is not supported.
+
 @item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
 A unix domain socket is used instead of a tcp socket.  The option works the
 same as if you had specified @code{-serial tcp} except the unix domain socket