ui: let VNC server listen on all resolved IP addresses

Remove the limitation that the VNC server can only listen on
a single resolved IP address. This uses the new DNS resolver
API to resolve a SocketAddress struct into an array of
SocketAddress structs containing raw IP addresses. The VNC
server will then attempt to listen on all resolved IP addresses.
The server must successfully listen on at least one of the
resolved IP addresses, otherwise an error will be reported.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170203120649.15637-7-berrange@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 43 insertions, 9 deletions

diff --git a/ui/vnc.c b/ui/vnc.c
index 02c0b89677..5c11c2dbd3 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -45,6 +45,7 @@
 #include "crypto/tlscredsx509.h"
 #include "qom/object_interfaces.h"
 #include "qemu/cutils.h"
+#include "io/dns-resolver.h"
 
 #define VNC_REFRESH_INTERVAL_BASE GUI_REFRESH_INTERVAL_DEFAULT
 #define VNC_REFRESH_INTERVAL_INC  50
@@ -3698,19 +3699,52 @@ static int vnc_display_listen_addr(VncDisplay *vd,
                                    size_t *nlsock,
                                    Error **errp)
 {
-    *nlsock = 1;
-    *lsock = g_new0(QIOChannelSocket *, 1);
-    *lsock_tag = g_new0(guint, 1);
+    QIODNSResolver *resolver = qio_dns_resolver_get_instance();
+    SocketAddress **rawaddrs = NULL;
+    size_t nrawaddrs = 0;
+    Error *listenerr = NULL;
+    size_t i;
 
-    (*lsock)[0] = qio_channel_socket_new();
-    qio_channel_set_name(QIO_CHANNEL((*lsock)[0]), name);
-    if (qio_channel_socket_listen_sync((*lsock)[0], addr, errp) < 0) {
+    if (qio_dns_resolver_lookup_sync(resolver, addr, &nrawaddrs,
+                                     &rawaddrs, errp) < 0) {
         return -1;
     }
 
-    (*lsock_tag)[0] = qio_channel_add_watch(
-        QIO_CHANNEL((*lsock)[0]),
-        G_IO_IN, vnc_listen_io, vd, NULL);
+    for (i = 0; i < nrawaddrs; i++) {
+        QIOChannelSocket *sioc = qio_channel_socket_new();
+
+        qio_channel_set_name(QIO_CHANNEL(sioc), name);
+        if (qio_channel_socket_listen_sync(
+                sioc, rawaddrs[i], listenerr == NULL ? &listenerr : NULL) < 0) {
+            continue;
+        }
+        (*nlsock)++;
+        *lsock = g_renew(QIOChannelSocket *, *lsock, *nlsock);
+        *lsock_tag = g_renew(guint, *lsock_tag, *nlsock);
+
+        (*lsock)[*nlsock - 1] = sioc;
+        (*lsock_tag)[*nlsock - 1] = 0;
+    }
+
+    for (i = 0; i < nrawaddrs; i++) {
+        qapi_free_SocketAddress(rawaddrs[i]);
+    }
+    g_free(rawaddrs);
+
+    if (listenerr) {
+        if (*nlsock == 0) {
+            error_propagate(errp, listenerr);
+            return -1;
+        } else {
+            error_free(listenerr);
+        }
+    }
+
+    for (i = 0; i < *nlsock; i++) {
+        (*lsock_tag)[i] = qio_channel_add_watch(
+            QIO_CHANNEL((*lsock)[i]),
+            G_IO_IN, vnc_listen_io, vd, NULL);
+    }
 
     return 0;
 }