gsocket: normalize ipv6 addresses before returning themv6only

If the socket family is AF_INET6 the remote address can be a v6-in-v4
address (such as ::ffff:172.22.64.188) which is actually quite
annoying. If we are in this case, normalize the address to AF_INET
instead.

Signed-off-by: Jonny Lamb <jonnylamb@gnome.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/gio/gsocket.c b/gio/gsocket.c
index 01792a7fe..2d32396c0 100644
--- a/gio/gsocket.c
+++ b/gio/gsocket.c
@@ -1216,6 +1216,33 @@ g_socket_get_fd (GSocket *socket)
   return socket->priv->fd;
 }
 
+/* If the family is AF_INET6 then this could be a v6-in-v4 which, when
+ * get_local_address or get_remote_address is called, should never be
+ * returned as is. No-one wants to have their IPv4 addresses
+ * represented by IPv6 addresses like ::ffff:172.22.64.188. Therefore,
+ * let's convert it to a real IPv4 address. */
+static void
+g_socket_normalize_address (struct sockaddr_storage *addr)
+{
+#if defined (IN6_IS_ADDR_V4MAPPED)
+  struct sockaddr_in *s4 = (struct sockaddr_in *) addr;
+  struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) addr;
+
+  if (s6->sin6_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED (&(s6->sin6_addr)))
+    {
+      u_int32_t addr_big_endian;
+      u_int16_t port;
+
+      memcpy (&addr_big_endian, s6->sin6_addr.s6_addr + 12, 4);
+      port = s6->sin6_port;
+
+      s4->sin_family = AF_INET;
+      s4->sin_addr.s_addr = addr_big_endian;
+      s4->sin_port = port;
+    }
+#endif
+}
+
 /**
  * g_socket_get_local_address:
  * @socket: a #GSocket.
@@ -1247,6 +1274,8 @@ g_socket_get_local_address (GSocket  *socket,
       return NULL;
     }
 
+  g_socket_normalize_address (&buffer);
+
   return g_socket_address_new_from_native (&buffer, len);
 }
 
@@ -1290,6 +1319,8 @@ g_socket_get_remote_address (GSocket  *socket,
 	  return NULL;
 	}
 
+      g_socket_normalize_address (&buffer);
+
       socket->priv->remote_address = g_socket_address_new_from_native (&buffer, len);
     }