seamless migration: src and dest servers handshake

Flow:
(1) *src* main channel coroutine (main_handle_migrate_begin_seamless):
    handles SPICE_MSG_MAIN_MIGRATE_BEGIN_SEAMLESS; yields to the main loop,
    supplying it the destination information needed for connection.
(2) main context (migrate_connect):
    Establishes a new session for connecting to the destination.
    After all the channels are opened (async), their state, except for
    the one of the main channel, is modified to
    SPICE_CHANNEL_STATE_MIGRATING (see migrate_channel_event_cb);
    no reading is done from the channel during this state.
    The dest main channel's state is changed to SPICE_CHANNEL_STATE_MIGRATION_HANDSHAKE

(3) *dest* main channel coroutine: sends to the dest server SPICE_MSGC_MAIN_MIGRATE_DST_DO_SEAMLESS
    (see spice_channel_recv_auth)
(4) *dest* main channel coroutine: recevices SPICE_MSG_MAIN_MIGRATE_DST_SEAMLESS_ACK/NACK.
     adds main_migrate_handshake_done to the main loop.
(5) main context: when all the dest session channels are connected, and the main channel handshake
    is done, we yield to the src main channel coroutine (see
    migrate_channel_event_cb and main_migrate_handshake_done)
(6) *src* main channel coroutine: sends to the src server
    SPICE_MSGC_MAIN_MIGRATE_(CONNECTED|CONNECTED_SEAMLESS|CONNECT_ERROR)

For more details see spice-protocol. commit
1ad5d259cb4b695ec3106de7ccd082e031e7ae11

1 files changed, 17 insertions, 0 deletions

diff --git a/gtk/spice-channel.c b/gtk/spice-channel.c
index 54d406d..5f37cbc 100644
--- a/gtk/spice-channel.c
+++ b/gtk/spice-channel.c
@@ -49,6 +49,7 @@ static void spice_channel_send_link(SpiceChannel *channel);
 static void channel_disconnect(SpiceChannel *channel);
 static void channel_reset(SpiceChannel *channel, gboolean migrating);
 static void spice_channel_reset_capabilities(SpiceChannel *channel);
+static void spice_channel_send_migration_handshake(SpiceChannel *channel);
 
 /**
  * SECTION:spice-channel
@@ -1080,6 +1081,10 @@ static void spice_channel_recv_auth(SpiceChannel *channel)
 
     emit_main_context(channel, SPICE_CHANNEL_EVENT, SPICE_CHANNEL_OPENED);
 
+    if (c->state == SPICE_CHANNEL_STATE_MIGRATION_HANDSHAKE) {
+        spice_channel_send_migration_handshake(channel);
+    }
+
     if (c->state != SPICE_CHANNEL_STATE_MIGRATING)
         spice_channel_up(channel);
 }
@@ -2002,6 +2007,7 @@ static void spice_channel_iterate_read(SpiceChannel *channel)
         spice_channel_recv_auth(channel);
         break;
     case SPICE_CHANNEL_STATE_READY:
+    case SPICE_CHANNEL_STATE_MIGRATION_HANDSHAKE:
         spice_channel_recv_msg(channel,
             (handler_msg_in)SPICE_CHANNEL_GET_CLASS(channel)->handle_msg, NULL);
         break;
@@ -2654,3 +2660,14 @@ static void spice_channel_reset_capabilities(SpiceChannel *channel)
         SPICE_CHANNEL_GET_CLASS(channel)->channel_reset_capabilities(channel);
     }
 }
+
+static void spice_channel_send_migration_handshake(SpiceChannel *channel)
+{
+    SpiceChannelPrivate *c = SPICE_CHANNEL_GET_PRIVATE(channel);
+
+    if (SPICE_CHANNEL_GET_CLASS(channel)->channel_send_migration_handshake) {
+        SPICE_CHANNEL_GET_CLASS(channel)->channel_send_migration_handshake(channel);
+    } else {
+        c->state = SPICE_CHANNEL_STATE_MIGRATING;
+    }
+}