Add VNC reverse connections, by Eddie Kohler.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3951 c046a42c-6fe2-441c-8c8c-71466251a162

qemu-doc.texi

@@ -421,21 +421,21 @@ syntax for the @var{display} is
 
 @table @code
 
-@item @var{interface}:@var{d}
+@item @var{host}:@var{d}
 
-TCP connections will only be allowed from @var{interface} on display @var{d}.
-By convention the TCP port is 5900+@var{d}. Optionally, @var{interface} can
-be omitted in which case the server will bind to all interfaces.
+TCP connections will only be allowed from @var{host} on display @var{d}.
+By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
+be omitted in which case the server will accept connections from any host.
 
-@item @var{unix}:@var{path}
+@item @code{unix}:@var{path}
 
 Connections will be allowed over UNIX domain sockets where @var{path} is the
 location of a unix socket to listen for connections on.
 
 @item none
 
-VNC is initialized by not started. The monitor @code{change} command can be used
-to later start the VNC server.
+VNC is initialized but not started. The monitor @code{change} command
+can be used to later start the VNC server.
 
 @end table
 
@@ -444,6 +444,13 @@ separated by commas. Valid options are
 
 @table @code
 
+@item reverse
+
+Connect to a listening VNC client via a ``reverse'' connection. The
+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 password
 
 Require that password based authentication is used for client connections.

vnc.c

@@ -1898,6 +1898,22 @@ static int protocol_version(VncState *vs, uint8_t *version, size_t len)
     return 0;
 }
 
+static void vnc_connect(VncState *vs)
+{
+    VNC_DEBUG("New client on socket %d\n", vs->csock);
+    socket_set_nonblock(vs->csock);
+    qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
+    vnc_write(vs, "RFB 003.008\n", 12);
+    vnc_flush(vs);
+    vnc_read_when(vs, protocol_version, 12);
+    memset(vs->old_data, 0, vs->ds->linesize * vs->ds->height);
+    memset(vs->dirty_row, 0xFF, sizeof(vs->dirty_row));
+    vs->has_resize = 0;
+    vs->has_hextile = 0;
+    vs->ds->dpy_copy = NULL;
+    vnc_update_client(vs);
+}
+
 static void vnc_listen_read(void *opaque)
 {
     VncState *vs = opaque;
@@ -1909,18 +1925,7 @@ static void vnc_listen_read(void *opaque)
 
     vs->csock = accept(vs->lsock, (struct sockaddr *)&addr, &addrlen);
     if (vs->csock != -1) {
-	VNC_DEBUG("New client on socket %d\n", vs->csock);
-        socket_set_nonblock(vs->csock);
-	qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, opaque);
-	vnc_write(vs, "RFB 003.008\n", 12);
-	vnc_flush(vs);
-	vnc_read_when(vs, protocol_version, 12);
-	memset(vs->old_data, 0, vs->ds->linesize * vs->ds->height);
-	memset(vs->dirty_row, 0xFF, sizeof(vs->dirty_row));
-	vs->has_resize = 0;
-	vs->has_hextile = 0;
-	vs->ds->dpy_copy = NULL;
-        vnc_update_client(vs);
+        vnc_connect(vs);
     }
 }
 
@@ -2087,6 +2092,7 @@ int vnc_display_open(DisplayState *ds, const char *display)
     VncState *vs = ds ? (VncState *)ds->opaque : vnc_state;
     const char *options;
     int password = 0;
+    int reverse = 0;
 #if CONFIG_VNC_TLS
     int tls = 0, x509 = 0;
 #endif
@@ -2103,6 +2109,8 @@ int vnc_display_open(DisplayState *ds, const char *display)
 	options++;
 	if (strncmp(options, "password", 8) == 0) {
 	    password = 1; /* Require password auth */
+	} else if (strncmp(options, "reverse", 7) == 0) {
+	    reverse = 1;
 #if CONFIG_VNC_TLS
 	} else if (strncmp(options, "tls", 3) == 0) {
 	    tls = 1; /* Require TLS */
@@ -2196,7 +2204,9 @@ int vnc_display_open(DisplayState *ds, const char *display)
 	memset(uaddr.sun_path, 0, 108);
 	snprintf(uaddr.sun_path, 108, "%s", p);
 
-	unlink(uaddr.sun_path);
+	if (!reverse) {
+	    unlink(uaddr.sun_path);
+	}
     } else
 #endif
     {
@@ -2210,7 +2220,7 @@ int vnc_display_open(DisplayState *ds, const char *display)
 	    return -1;
 	}
 
-	iaddr.sin_port = htons(ntohs(iaddr.sin_port) + 5900);
+	iaddr.sin_port = htons(ntohs(iaddr.sin_port) + (reverse ? 0 : 5900));
 
 	vs->lsock = socket(PF_INET, SOCK_STREAM, 0);
 	if (vs->lsock == -1) {
@@ -2233,6 +2243,22 @@ int vnc_display_open(DisplayState *ds, const char *display)
 	}
     }
 
+    if (reverse) {
+        if (connect(vs->lsock, addr, addrlen) == -1) {
+            fprintf(stderr, "Connection to VNC client failed\n");
+            close(vs->lsock);
+            vs->lsock = -1;
+            free(vs->display);
+            vs->display = NULL;
+            return -1;
+        } else {
+            vs->csock = vs->lsock;
+            vs->lsock = -1;
+            vnc_connect(vs);
+            return 0;
+        }
+    }
+
     if (bind(vs->lsock, addr, addrlen) == -1) {
 	fprintf(stderr, "bind() failed\n");
 	close(vs->lsock);