Introduce VIR_NET_STREAM_HOLE message type

This is a special type of stream packet, that is bidirectional
and contains information regarding how many bytes each side will
be skipping in the stream.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

daemon/stream.c

@@ -287,7 +287,8 @@ daemonStreamFilter(virNetServerClientPtr client ATTRIBUTE_UNUSED,
 
     virMutexLock(&stream->priv->lock);
 
-    if (msg->header.type != VIR_NET_STREAM)
+    if (msg->header.type != VIR_NET_STREAM &&
+        msg->header.type != VIR_NET_STREAM_HOLE)
         goto cleanup;
 
     if (!virNetServerProgramMatches(stream->prog, msg))

src/rpc/virnetclient.c

@@ -1284,6 +1284,7 @@ virNetClientCallDispatch(virNetClientPtr client)
         return virNetClientCallDispatchMessage(client);
 
     case VIR_NET_STREAM: /* Stream protocol */
+    case VIR_NET_STREAM_HOLE: /* Sparse stream protocol*/
         return virNetClientCallDispatchStream(client);
 
     default:

src/rpc/virnetprotocol.x

@@ -143,6 +143,14 @@ const VIR_NET_MESSAGE_NUM_FDS_MAX = 32;
  *     * status == VIR_NET_ERROR
  *          remote_error    Error information
  *
+ *  - type == VIR_NET_STREAM_HOLE
+ *     * status == VIR_NET_CONTINUE
+ *          byte[]  hole data
+ *     * status == VIR_NET_ERROR
+ *          remote_error error information
+ *     * status == VIR_NET_OK
+ *          <empty>
+ *
  */
 enum virNetMessageType {
     /* client -> server. args from a method call */
@@ -156,7 +164,9 @@ enum virNetMessageType {
     /* client -> server. args from a method call, with passed FDs */
     VIR_NET_CALL_WITH_FDS = 4,
     /* server -> client. reply/error from a method call, with passed FDs */
-    VIR_NET_REPLY_WITH_FDS = 5
+    VIR_NET_REPLY_WITH_FDS = 5,
+    /* either direction, stream hole data packet */
+    VIR_NET_STREAM_HOLE = 6
 };
 
 enum virNetMessageStatus {

src/virnetprotocol-structs

@@ -6,6 +6,7 @@ enum virNetMessageType {
         VIR_NET_STREAM = 3,
         VIR_NET_CALL_WITH_FDS = 4,
         VIR_NET_REPLY_WITH_FDS = 5,
+        VIR_NET_STREAM_HOLE = 6,
 };
 enum virNetMessageStatus {
         VIR_NET_OK = 0,