vnc: added initial websocket protocol support

This patch adds basic Websocket Protocol version 13 - RFC 6455 - support
to QEMU VNC. Binary encoding support on the client side is mandatory.

Because of the GnuTLS requirement the Websockets implementation is
optional (--enable-vnc-ws).

To activate Websocket support the VNC option "websocket"is used, for
example "-vnc :0,websocket".
The listen port for Websocket connections is (5700 + display) so if
QEMU VNC is started with :0 the Websocket port would be 5700.
As an alternative the Websocket port could be manually specified by
using ",websocket=<port>" instead.

Parts of the implementation base on Anthony Liguori's QEMU Websocket
patch from 2010 and on Joel Martin's LibVNC Websocket implementation.

Signed-off-by: Tim Hardeck <thardeck@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

7 files changed, 591 insertions, 21 deletions

diff --git a/configure b/configure
index 6211db9..c6172ef 100755
--- a/configure
+++ b/configure
@@ -158,6 +158,7 @@ vnc_tls=""
 vnc_sasl=""
 vnc_jpeg=""
 vnc_png=""
+vnc_ws=""
 xen=""
 xen_ctrl_version=""
 xen_pci_passthrough=""
@@ -724,6 +725,10 @@ for opt do
   ;;
   --enable-vnc-png) vnc_png="yes"
   ;;
+  --disable-vnc-ws) vnc_ws="no"
+  ;;
+  --enable-vnc-ws) vnc_ws="yes"
+  ;;
   --disable-slirp) slirp="no"
   ;;
   --disable-uuid) uuid="no"
@@ -1069,6 +1074,8 @@ echo "  --disable-vnc-jpeg       disable JPEG lossy compression for VNC server"
 echo "  --enable-vnc-jpeg        enable JPEG lossy compression for VNC server"
 echo "  --disable-vnc-png        disable PNG compression for VNC server (default)"
 echo "  --enable-vnc-png         enable PNG compression for VNC server"
+echo "  --disable-vnc-ws         disable Websockets support for VNC server"
+echo "  --enable-vnc-ws          enable Websockets support for VNC server"
 echo "  --disable-curses         disable curses output"
 echo "  --enable-curses          enable curses output"
 echo "  --disable-curl           disable curl connectivity"
@@ -1712,8 +1719,8 @@ EOF
 fi
 
 ##########################################
-# VNC TLS detection
-if test "$vnc" = "yes" -a "$vnc_tls" != "no" ; then
+# VNC TLS/WS detection
+if test "$vnc" = "yes" -a \( "$vnc_tls" != "no" -o "$vnc_ws" != "no" \) ; then
   cat > $TMPC <<EOF
 #include <gnutls/gnutls.h>
 int main(void) { gnutls_session_t s; gnutls_init(&s, GNUTLS_SERVER); return 0; }
@@ -1721,14 +1728,23 @@ EOF
   vnc_tls_cflags=`$pkg_config --cflags gnutls 2> /dev/null`
   vnc_tls_libs=`$pkg_config --libs gnutls 2> /dev/null`
   if compile_prog "$vnc_tls_cflags" "$vnc_tls_libs" ; then
-    vnc_tls=yes
+    if test "$vnc_tls" != "no" ; then
+      vnc_tls=yes
+    fi
+    if test "$vnc_ws" != "no" ; then
+      vnc_ws=yes
+    fi
     libs_softmmu="$vnc_tls_libs $libs_softmmu"
     QEMU_CFLAGS="$QEMU_CFLAGS $vnc_tls_cflags"
   else
     if test "$vnc_tls" = "yes" ; then
       feature_not_found "vnc-tls"
     fi
+    if test "$vnc_ws" = "yes" ; then
+      feature_not_found "vnc-ws"
+    fi
     vnc_tls=no
+    vnc_ws=no
   fi
 fi
 
@@ -3283,6 +3299,7 @@ if test "$vnc" = "yes" ; then
     echo "VNC SASL support  $vnc_sasl"
     echo "VNC JPEG support  $vnc_jpeg"
     echo "VNC PNG support   $vnc_png"
+    echo "VNC WS support    $vnc_ws"
 fi
 if test -n "$sparc_cpu"; then
     echo "Target Sparc Arch $sparc_cpu"
@@ -3461,6 +3478,10 @@ fi
 if test "$vnc_png" = "yes" ; then
   echo "CONFIG_VNC_PNG=y" >> $config_host_mak
 fi
+if test "$vnc_ws" = "yes" ; then
+  echo "CONFIG_VNC_WS=y" >> $config_host_mak
+  echo "VNC_WS_CFLAGS=$vnc_ws_cflags" >> $config_host_mak
+fi
 if test "$fnmatch" = "yes" ; then
   echo "CONFIG_FNMATCH=y" >> $config_host_mak
 fi
diff --git a/qemu-options.hx b/qemu-options.hx
index 40cd683..4e2b499 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1096,6 +1096,14 @@ client is specified by the @var{display}. For reverse network
 connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
 is a TCP port number, not a display number.
 
+@item websocket
+
+Opens an additional TCP listening port dedicated to VNC Websocket connections.
+By defintion the Websocket port is 5700+@var{display}. If @var{host} is
+specified connections will only be allowed from this host.
+As an alternative the Websocket port could be specified by using
+@code{websocket}=@var{port}.
+
 @item password
 
 Require that password based authentication is used for client connections.
diff --git a/ui/Makefile.objs b/ui/Makefile.objs
index 6768bb7..d9db073 100644
--- a/ui/Makefile.objs
+++ b/ui/Makefile.objs
@@ -4,6 +4,7 @@ vnc-obj-y += vnc-enc-tight.o vnc-palette.o
 vnc-obj-y += vnc-enc-zrle.o
 vnc-obj-$(CONFIG_VNC_TLS) += vnc-tls.o vnc-auth-vencrypt.o
 vnc-obj-$(CONFIG_VNC_SASL) += vnc-auth-sasl.o
+vnc-obj-$(CONFIG_VNC_WS) += vnc-ws.o
 vnc-obj-y += vnc-jobs.o
 
 common-obj-y += keymaps.o console.o cursor.o input.o qemu-pixman.o
diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c
new file mode 100644
index 0000000..9ccdc19
--- /dev/null
+++ b/ui/vnc-ws.c
@@ -0,0 +1,284 @@
+/*
+ * QEMU VNC display driver: Websockets support
+ *
+ * Copyright (C) 2010 Joel Martin
+ * Copyright (C) 2012 Tim Hardeck
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "vnc.h"
+
+void vncws_handshake_read(void *opaque)
+{
+    VncState *vs = opaque;
+    uint8_t *handshake_end;
+    long ret;
+    buffer_reserve(&vs->ws_input, 4096);
+    ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), 4096);
+
+    if (!ret) {
+        if (vs->csock == -1) {
+            vnc_disconnect_finish(vs);
+        }
+        return;
+    }
+    vs->ws_input.offset += ret;
+
+    handshake_end = (uint8_t *)g_strstr_len((char *)vs->ws_input.buffer,
+            vs->ws_input.offset, WS_HANDSHAKE_END);
+    if (handshake_end) {
+        qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
+        vncws_process_handshake(vs, vs->ws_input.buffer, vs->ws_input.offset);
+        buffer_advance(&vs->ws_input, handshake_end - vs->ws_input.buffer +
+                strlen(WS_HANDSHAKE_END));
+    }
+}
+
+
+long vnc_client_read_ws(VncState *vs)
+{
+    int ret, err;
+    uint8_t *payload;
+    size_t payload_size, frame_size;
+    VNC_DEBUG("Read websocket %p size %zd offset %zd\n", vs->ws_input.buffer,
+            vs->ws_input.capacity, vs->ws_input.offset);
+    buffer_reserve(&vs->ws_input, 4096);
+    ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), 4096);
+    if (!ret) {
+        return 0;
+    }
+    vs->ws_input.offset += ret;
+
+    /* make sure that nothing is left in the ws_input buffer */
+    do {
+        err = vncws_decode_frame(&vs->ws_input, &payload,
+                              &payload_size, &frame_size);
+        if (err <= 0) {
+            return err;
+        }
+
+        buffer_reserve(&vs->input, payload_size);
+        buffer_append(&vs->input, payload, payload_size);
+
+        buffer_advance(&vs->ws_input, frame_size);
+    } while (vs->ws_input.offset > 0);
+
+    return ret;
+}
+
+long vnc_client_write_ws(VncState *vs)
+{
+    long ret;
+    VNC_DEBUG("Write WS: Pending output %p size %zd offset %zd\n",
+              vs->output.buffer, vs->output.capacity, vs->output.offset);
+    vncws_encode_frame(&vs->ws_output, vs->output.buffer, vs->output.offset);
+    buffer_reset(&vs->output);
+    ret = vnc_client_write_buf(vs, vs->ws_output.buffer, vs->ws_output.offset);
+    if (!ret) {
+        return 0;
+    }
+
+    buffer_advance(&vs->ws_output, ret);
+
+    if (vs->ws_output.offset == 0) {
+        qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
+    }
+
+    return ret;
+}
+
+static char *vncws_extract_handshake_entry(const char *handshake,
+        size_t handshake_len, const char *name)
+{
+    char *begin, *end, *ret = NULL;
+    char *line = g_strdup_printf("%s%s: ", WS_HANDSHAKE_DELIM, name);
+    begin = g_strstr_len(handshake, handshake_len, line);
+    if (begin != NULL) {
+        begin += strlen(line);
+        end = g_strstr_len(begin, handshake_len - (begin - handshake),
+                WS_HANDSHAKE_DELIM);
+        if (end != NULL) {
+            ret = g_strndup(begin, end - begin);
+        }
+    }
+    g_free(line);
+    return ret;
+}
+
+static void vncws_send_handshake_response(VncState *vs, const char* key)
+{
+    char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1];
+    char hash[SHA1_DIGEST_LEN];
+    size_t hash_size = SHA1_DIGEST_LEN;
+    char *accept = NULL, *response = NULL;
+    gnutls_datum_t in;
+
+    g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1);
+    g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1);
+
+    /* hash and encode it */
+    in.data = (void *)combined_key;
+    in.size = WS_CLIENT_KEY_LEN + WS_GUID_LEN;
+    if (gnutls_fingerprint(GNUTLS_DIG_SHA1, &in, hash, &hash_size)
+            == GNUTLS_E_SUCCESS) {
+        accept = g_base64_encode((guchar *)hash, SHA1_DIGEST_LEN);
+    }
+    if (accept == NULL) {
+        VNC_DEBUG("Hashing Websocket combined key failed\n");
+        vnc_client_error(vs);
+        return;
+    }
+
+    response = g_strdup_printf(WS_HANDSHAKE, accept);
+    vnc_write(vs, response, strlen(response));
+    vnc_flush(vs);
+
+    g_free(accept);
+    g_free(response);
+
+    vs->encode_ws = 1;
+    vnc_init_state(vs);
+}
+
+void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size)
+{
+    char *protocols = vncws_extract_handshake_entry((const char *)line, size,
+            "Sec-WebSocket-Protocol");
+    char *version = vncws_extract_handshake_entry((const char *)line, size,
+            "Sec-WebSocket-Version");
+    char *key = vncws_extract_handshake_entry((const char *)line, size,
+            "Sec-WebSocket-Key");
+
+    if (protocols && version && key
+            && g_strrstr(protocols, "binary")
+            && !strcmp(version, WS_SUPPORTED_VERSION)
+            && strlen(key) == WS_CLIENT_KEY_LEN) {
+        vncws_send_handshake_response(vs, key);
+    } else {
+        VNC_DEBUG("Defective Websockets header or unsupported protocol\n");
+        vnc_client_error(vs);
+    }
+
+    g_free(protocols);
+    g_free(version);
+    g_free(key);
+}
+
+void vncws_encode_frame(Buffer *output, const void *payload,
+        const size_t payload_size)
+{
+    size_t header_size = 0;
+    unsigned char opcode = WS_OPCODE_BINARY_FRAME;
+    union {
+        char buf[WS_HEAD_MAX_LEN];
+        WsHeader ws;
+    } header;
+
+    if (!payload_size) {
+        return;
+    }
+
+    header.ws.b0 = 0x80 | (opcode & 0x0f);
+    if (payload_size <= 125) {
+        header.ws.b1 = (uint8_t)payload_size;
+        header_size = 2;
+    } else if (payload_size < 65536) {
+        header.ws.b1 = 0x7e;
+        header.ws.u.s16.l16 = cpu_to_be16((uint16_t)payload_size);
+        header_size = 4;
+    } else {
+        header.ws.b1 = 0x7f;
+        header.ws.u.s64.l64 = cpu_to_be64(payload_size);
+        header_size = 10;
+    }
+
+    buffer_reserve(output, header_size + payload_size);
+    buffer_append(output, header.buf, header_size);
+    buffer_append(output, payload, payload_size);
+}
+
+int vncws_decode_frame(Buffer *input, uint8_t **payload,
+                           size_t *payload_size, size_t *frame_size)
+{
+    unsigned char opcode = 0, fin = 0, has_mask = 0;
+    size_t header_size = 0;
+    uint32_t *payload32;
+    WsHeader *header = (WsHeader *)input->buffer;
+    WsMask mask;
+    int i;
+
+    if (input->offset < WS_HEAD_MIN_LEN + 4) {
+        /* header not complete */
+        return 0;
+    }
+
+    fin = (header->b0 & 0x80) >> 7;
+    opcode = header->b0 & 0x0f;
+    has_mask = (header->b1 & 0x80) >> 7;
+    *payload_size = header->b1 & 0x7f;
+
+    if (opcode == WS_OPCODE_CLOSE) {
+        /* disconnect */
+        return -1;
+    }
+
+    /* Websocket frame sanity check:
+     * * Websocket fragmentation is not supported.
+     * * All  websockets frames sent by a client have to be masked.
+     * * Only binary encoding is supported.
+     */
+    if (!fin || !has_mask || opcode != WS_OPCODE_BINARY_FRAME) {
+        VNC_DEBUG("Received faulty/unsupported Websocket frame\n");
+        return -2;
+    }
+
+    if (*payload_size < 126) {
+        header_size = 6;
+        mask = header->u.m;
+    } else if (*payload_size == 126 && input->offset >= 8) {
+        *payload_size = be16_to_cpu(header->u.s16.l16);
+        header_size = 8;
+        mask = header->u.s16.m16;
+    } else if (*payload_size == 127 && input->offset >= 14) {
+        *payload_size = be64_to_cpu(header->u.s64.l64);
+        header_size = 14;
+        mask = header->u.s64.m64;
+    } else {
+        /* header not complete */
+        return 0;
+    }
+
+    *frame_size = header_size + *payload_size;
+
+    if (input->offset < *frame_size) {
+        /* frame not complete */
+        return 0;
+    }
+
+    *payload = input->buffer + header_size;
+
+    /* unmask frame */
+    /* process 1 frame (32 bit op) */
+    payload32 = (uint32_t *)(*payload);
+    for (i = 0; i < *payload_size / 4; i++) {
+        payload32[i] ^= mask.u;
+    }
+    /* process the remaining bytes (if any) */
+    for (i *= 4; i < *payload_size; i++) {
+        (*payload)[i] ^= mask.c[i % 4];
+    }
+
+    return 1;
+}
diff --git a/ui/vnc-ws.h b/ui/vnc-ws.h
new file mode 100644
index 0000000..039a587
--- /dev/null
+++ b/ui/vnc-ws.h
@@ -0,0 +1,86 @@
+/*
+ * QEMU VNC display driver: Websockets support
+ *
+ * Copyright (C) 2010 Joel Martin
+ * Copyright (C) 2012 Tim Hardeck
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __QEMU_UI_VNC_WS_H
+#define __QEMU_UI_VNC_WS_H
+
+#include <gnutls/gnutls.h>
+
+#define B64LEN(__x) (((__x + 2) / 3) * 12 / 3)
+#define SHA1_DIGEST_LEN 20
+
+#define WS_ACCEPT_LEN (B64LEN(SHA1_DIGEST_LEN) + 1)
+#define WS_CLIENT_KEY_LEN 24
+#define WS_GUID "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
+#define WS_GUID_LEN strlen(WS_GUID)
+
+#define WS_HANDSHAKE "HTTP/1.1 101 Switching Protocols\r\n\
+Upgrade: websocket\r\n\
+Connection: Upgrade\r\n\
+Sec-WebSocket-Accept: %s\r\n\
+Sec-WebSocket-Protocol: binary\r\n\
+\r\n"
+#define WS_HANDSHAKE_DELIM "\r\n"
+#define WS_HANDSHAKE_END "\r\n\r\n"
+#define WS_SUPPORTED_VERSION "13"
+
+#define WS_HEAD_MIN_LEN sizeof(uint16_t)
+#define WS_HEAD_MAX_LEN (WS_HEAD_MIN_LEN + sizeof(uint64_t) + sizeof(uint32_t))
+
+typedef union WsMask {
+    char c[4];
+    uint32_t u;
+} WsMask;
+
+typedef struct QEMU_PACKED WsHeader {
+    unsigned char b0;
+    unsigned char b1;
+    union {
+        struct QEMU_PACKED {
+            uint16_t l16;
+            WsMask m16;
+        } s16;
+        struct QEMU_PACKED {
+            uint64_t l64;
+            WsMask m64;
+        } s64;
+        WsMask m;
+    } u;
+} WsHeader;
+
+enum {
+    WS_OPCODE_CONTINUATION = 0x0,
+    WS_OPCODE_TEXT_FRAME = 0x1,
+    WS_OPCODE_BINARY_FRAME = 0x2,
+    WS_OPCODE_CLOSE = 0x8,
+    WS_OPCODE_PING = 0x9,
+    WS_OPCODE_PONG = 0xA
+};
+
+void vncws_handshake_read(void *opaque);
+long vnc_client_write_ws(VncState *vs);
+long vnc_client_read_ws(VncState *vs);
+void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size);
+void vncws_encode_frame(Buffer *output, const void *payload,
+            const size_t payload_size);
+int vncws_decode_frame(Buffer *input, uint8_t **payload,
+                               size_t *payload_size, size_t *frame_size);
+
+#endif /* __QEMU_UI_VNC_WS_H */
diff --git a/ui/vnc.c b/ui/vnc.c
index ddf01f1..ee08894 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -420,7 +420,6 @@ out_error:
 static int vnc_update_client(VncState *vs, int has_dirty);
 static int vnc_update_client_sync(VncState *vs, int has_dirty);
 static void vnc_disconnect_start(VncState *vs);
-static void vnc_disconnect_finish(VncState *vs);
 static void vnc_init_timer(VncDisplay *vd);
 static void vnc_remove_timer(VncDisplay *vd);
 
@@ -486,7 +485,7 @@ static int buffer_empty(Buffer *buffer)
     return buffer->offset == 0;
 }
 
-static uint8_t *buffer_end(Buffer *buffer)
+uint8_t *buffer_end(Buffer *buffer)
 {
     return buffer->buffer + buffer->offset;
 }
@@ -1023,7 +1022,7 @@ static void vnc_disconnect_start(VncState *vs)
     vs->csock = -1;
 }
 
-static void vnc_disconnect_finish(VncState *vs)
+void vnc_disconnect_finish(VncState *vs)
 {
     int i;
 
@@ -1034,6 +1033,10 @@ static void vnc_disconnect_finish(VncState *vs)
 
     buffer_free(&vs->input);
     buffer_free(&vs->output);
+#ifdef CONFIG_VNC_WS
+    buffer_free(&vs->ws_input);
+    buffer_free(&vs->ws_output);
+#endif /* CONFIG_VNC_WS */
 
     qobject_decref(vs->info);
 
@@ -1199,7 +1202,16 @@ static void vnc_client_write_locked(void *opaque)
         vnc_client_write_sasl(vs);
     } else
 #endif /* CONFIG_VNC_SASL */
-        vnc_client_write_plain(vs);
+    {
+#ifdef CONFIG_VNC_WS
+        if (vs->encode_ws) {
+            vnc_client_write_ws(vs);
+        } else
+#endif /* CONFIG_VNC_WS */
+        {
+            vnc_client_write_plain(vs);
+        }
+    }
 }
 
 void vnc_client_write(void *opaque)
@@ -1207,7 +1219,11 @@ void vnc_client_write(void *opaque)
     VncState *vs = opaque;
 
     vnc_lock_output(vs);
-    if (vs->output.offset) {
+    if (vs->output.offset
+#ifdef CONFIG_VNC_WS
+            || vs->ws_output.offset
+#endif
+            ) {
         vnc_client_write_locked(opaque);
     } else if (vs->csock != -1) {
         qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
@@ -1301,7 +1317,21 @@ void vnc_client_read(void *opaque)
         ret = vnc_client_read_sasl(vs);
     else
 #endif /* CONFIG_VNC_SASL */
+#ifdef CONFIG_VNC_WS
+        if (vs->encode_ws) {
+            ret = vnc_client_read_ws(vs);
+            if (ret == -1) {
+                vnc_disconnect_start(vs);
+                return;
+            } else if (ret == -2) {
+                vnc_client_error(vs);
+                return;
+            }
+        } else
+#endif /* CONFIG_VNC_WS */
+        {
         ret = vnc_client_read_plain(vs);
+        }
     if (!ret) {
         if (vs->csock == -1)
             vnc_disconnect_finish(vs);
@@ -1372,7 +1402,11 @@ void vnc_write_u8(VncState *vs, uint8_t value)
 void vnc_flush(VncState *vs)
 {
     vnc_lock_output(vs);
-    if (vs->csock != -1 && vs->output.offset) {
+    if (vs->csock != -1 && (vs->output.offset
+#ifdef CONFIG_VNC_WS
+                || vs->ws_output.offset
+#endif
+                )) {
         vnc_client_write_locked(vs);
     }
     vnc_unlock_output(vs);
@@ -2662,7 +2696,7 @@ static void vnc_remove_timer(VncDisplay *vd)
     }
 }
 
-static void vnc_connect(VncDisplay *vd, int csock, int skipauth)
+static void vnc_connect(VncDisplay *vd, int csock, int skipauth, bool websocket)
 {
     VncState *vs = g_malloc0(sizeof(VncState));
     int i;
@@ -2689,13 +2723,34 @@ static void vnc_connect(VncDisplay *vd, int csock, int skipauth)
     VNC_DEBUG("New client on socket %d\n", csock);
     dcl->idle = 0;
     socket_set_nonblock(vs->csock);
-    qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
+#ifdef CONFIG_VNC_WS
+    if (websocket) {
+        vs->websocket = 1;
+        qemu_set_fd_handler2(vs->csock, NULL, vncws_handshake_read, NULL, vs);
+    } else
+#endif /* CONFIG_VNC_WS */
+    {
+        qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
+    }
 
     vnc_client_cache_addr(vs);
     vnc_qmp_event(vs, QEVENT_VNC_CONNECTED);
     vnc_set_share_mode(vs, VNC_SHARE_MODE_CONNECTING);
 
     vs->vd = vd;
+
+#ifdef CONFIG_VNC_WS
+    if (!vs->websocket)
+#endif
+    {
+        vnc_init_state(vs);
+    }
+}
+
+void vnc_init_state(VncState *vs)
+{
+    VncDisplay *vd = vs->vd;
+
     vs->ds = vd->ds;
     vs->last_x = -1;
     vs->last_y = -1;
@@ -2727,21 +2782,41 @@ static void vnc_connect(VncDisplay *vd, int csock, int skipauth)
     /* vs might be free()ed here */
 }
 
-static void vnc_listen_read(void *opaque)
+static void vnc_listen_read(void *opaque, bool websocket)
 {
     VncDisplay *vs = opaque;
     struct sockaddr_in addr;
     socklen_t addrlen = sizeof(addr);
+    int csock;
 
     /* Catch-up */
     vga_hw_update();
+#ifdef CONFIG_VNC_WS
+    if (websocket) {
+        csock = qemu_accept(vs->lwebsock, (struct sockaddr *)&addr, &addrlen);
+    } else
+#endif /* CONFIG_VNC_WS */
+    {
+        csock = qemu_accept(vs->lsock, (struct sockaddr *)&addr, &addrlen);
+    }
 
-    int csock = qemu_accept(vs->lsock, (struct sockaddr *)&addr, &addrlen);
     if (csock != -1) {
-        vnc_connect(vs, csock, 0);
+        vnc_connect(vs, csock, 0, websocket);
     }
 }
 
+static void vnc_listen_regular_read(void *opaque)
+{
+    vnc_listen_read(opaque, 0);
+}
+
+#ifdef CONFIG_VNC_WS
+static void vnc_listen_websocket_read(void *opaque)
+{
+    vnc_listen_read(opaque, 1);
+}
+#endif /* CONFIG_VNC_WS */
+
 void vnc_display_init(DisplayState *ds)
 {
     VncDisplay *vs = g_malloc0(sizeof(*vs));
@@ -2753,6 +2828,9 @@ void vnc_display_init(DisplayState *ds)
     vnc_display = vs;
 
     vs->lsock = -1;
+#ifdef CONFIG_VNC_WS
+    vs->lwebsock = -1;
+#endif
 
     vs->ds = ds;
     QTAILQ_INIT(&vs->clients);
@@ -2794,6 +2872,15 @@ static void vnc_display_close(DisplayState *ds)
         close(vs->lsock);
         vs->lsock = -1;
     }
+#ifdef CONFIG_VNC_WS
+    g_free(vs->ws_display);
+    vs->ws_display = NULL;
+    if (vs->lwebsock != -1) {
+        qemu_set_fd_handler2(vs->lwebsock, NULL, NULL, NULL, NULL);
+        close(vs->lwebsock);
+        vs->lwebsock = -1;
+    }
+#endif /* CONFIG_VNC_WS */
     vs->auth = VNC_AUTH_INVALID;
 #ifdef CONFIG_VNC_TLS
     vs->subauth = VNC_AUTH_INVALID;
@@ -2915,6 +3002,36 @@ void vnc_display_open(DisplayState *ds, const char *display, Error **errp)
         } else if (strncmp(options, "sasl", 4) == 0) {
             sasl = 1; /* Require SASL auth */
 #endif
+#ifdef CONFIG_VNC_WS
+        } else if (strncmp(options, "websocket", 9) == 0) {
+            char *start, *end;
+            vs->websocket = 1;
+
+            /* Check for 'websocket=<port>' */
+            start = strchr(options, '=');
+            end = strchr(options, ',');
+            if (start && (!end || (start < end))) {
+                int len = end ? end-(start+1) : strlen(start+1);
+                if (len < 6) {
+                    /* extract the host specification from display */
+                    char  *host = NULL, *port = NULL, *host_end = NULL;
+                    port = g_strndup(start + 1, len);
+
+                    /* ipv6 hosts have colons */
+                    end = strchr(display, ',');
+                    host_end = g_strrstr_len(display, end - display, ":");
+
+                    if (host_end) {
+                        host = g_strndup(display, host_end - display + 1);
+                    } else {
+                        host = g_strndup(":", 1);
+                    }
+                    vs->ws_display = g_strconcat(host, port, NULL);
+                    g_free(host);
+                    g_free(port);
+                }
+            }
+#endif /* CONFIG_VNC_WS */
 #ifdef CONFIG_VNC_TLS
         } else if (strncmp(options, "tls", 3) == 0) {
             tls = 1; /* Require TLS */
@@ -3073,6 +3190,9 @@ void vnc_display_open(DisplayState *ds, const char *display, Error **errp)
         /* connect to viewer */
         int csock;
         vs->lsock = -1;
+#ifdef CONFIG_VNC_WS
+        vs->lwebsock = -1;
+#endif
         if (strncmp(display, "unix:", 5) == 0) {
             csock = unix_connect(display+5, errp);
         } else {
@@ -3081,7 +3201,7 @@ void vnc_display_open(DisplayState *ds, const char *display, Error **errp)
         if (csock < 0) {
             goto fail;
         }
-        vnc_connect(vs, csock, 0);
+        vnc_connect(vs, csock, 0, 0);
     } else {
         /* listen for connects */
         char *dpy;
@@ -3092,25 +3212,56 @@ void vnc_display_open(DisplayState *ds, const char *display, Error **errp)
         } else {
             vs->lsock = inet_listen(display, dpy, 256,
                                     SOCK_STREAM, 5900, errp);
-        }
-        if (vs->lsock < 0) {
-            g_free(dpy);
-            goto fail;
+            if (vs->lsock < 0) {
+                g_free(dpy);
+                goto fail;
+            }
+#ifdef CONFIG_VNC_WS
+            if (vs->websocket) {
+                if (vs->ws_display) {
+                    vs->lwebsock = inet_listen(vs->ws_display, NULL, 256,
+                        SOCK_STREAM, 0, errp);
+                } else {
+                    vs->lwebsock = inet_listen(vs->display, NULL, 256,
+                        SOCK_STREAM, 5700, errp);
+                }
+
+                if (vs->lwebsock < 0) {
+                    if (vs->lsock) {
+                        close(vs->lsock);
+                        vs->lsock = -1;
+                    }
+                    g_free(dpy);
+                    goto fail;
+                }
+            }
+#endif /* CONFIG_VNC_WS */
         }
         g_free(vs->display);
         vs->display = dpy;
-        qemu_set_fd_handler2(vs->lsock, NULL, vnc_listen_read, NULL, vs);
+        qemu_set_fd_handler2(vs->lsock, NULL,
+                vnc_listen_regular_read, NULL, vs);
+#ifdef CONFIG_VNC_WS
+        if (vs->websocket) {
+            qemu_set_fd_handler2(vs->lwebsock, NULL,
+                    vnc_listen_websocket_read, NULL, vs);
+        }
+#endif /* CONFIG_VNC_WS */
     }
     return;
 
 fail:
     g_free(vs->display);
     vs->display = NULL;
+#ifdef CONFIG_VNC_WS
+    g_free(vs->ws_display);
+    vs->ws_display = NULL;
+#endif /* CONFIG_VNC_WS */
 }
 
 void vnc_display_add_client(DisplayState *ds, int csock, int skipauth)
 {
     VncDisplay *vs = ds ? (VncDisplay *)ds->opaque : vnc_display;
 
-    vnc_connect(vs, csock, skipauth);
+    vnc_connect(vs, csock, skipauth, 0);
 }
diff --git a/ui/vnc.h b/ui/vnc.h
index 5059cbe..f93c89a 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -99,6 +99,9 @@ typedef struct VncDisplay VncDisplay;
 #ifdef CONFIG_VNC_SASL
 #include "vnc-auth-sasl.h"
 #endif
+#ifdef CONFIG_VNC_WS
+#include "vnc-ws.h"
+#endif
 
 struct VncRectStat
 {
@@ -142,6 +145,11 @@ struct VncDisplay
     QEMUTimer *timer;
     int timer_interval;
     int lsock;
+#ifdef CONFIG_VNC_WS
+    int lwebsock;
+    bool websocket;
+    char *ws_display;
+#endif
     DisplayState *ds;
     kbd_layout_t *kbd_layout;
     int lock_key_sync;
@@ -269,11 +277,19 @@ struct VncState
 #ifdef CONFIG_VNC_SASL
     VncStateSASL sasl;
 #endif
+#ifdef CONFIG_VNC_WS
+    bool encode_ws;
+    bool websocket;
+#endif
 
     QObject *info;
 
     Buffer output;
     Buffer input;
+#ifdef CONFIG_VNC_WS
+    Buffer ws_input;
+    Buffer ws_output;
+#endif
     /* current output mode information */
     VncWritePixels *write_pixels;
     PixelFormat client_pf;
@@ -493,6 +509,8 @@ void vnc_write_u16(VncState *vs, uint16_t value);
 void vnc_write_u8(VncState *vs, uint8_t value);
 void vnc_flush(VncState *vs);
 void vnc_read_when(VncState *vs, VncReadEvent *func, size_t expecting);
+void vnc_disconnect_finish(VncState *vs);
+void vnc_init_state(VncState *vs);
 
 
 /* Buffer I/O functions */
@@ -511,6 +529,7 @@ void buffer_reset(Buffer *buffer);
 void buffer_free(Buffer *buffer);
 void buffer_append(Buffer *buffer, const void *data, size_t len);
 void buffer_advance(Buffer *buf, size_t len);
+uint8_t *buffer_end(Buffer *buffer);
 
 
 /* Misc helpers */