server/spice.h: semi-seamless migration interface, RHBZ #738266

semi-seamless migration details:

migration source side
---------------------
(1) spice_server_migrate_connect (*): tell client to link
    to the target side - send SPICE_MSG_MAIN_MIGRATE_BEGIN.
    This should be called upon client_migrate_info cmd.
    client_migrate_info is asynchronous.
(2) Complete spice_server_migrate_connect only when the client has been connected
    to the target - wait for SPICE_MSGC_MAIN_MIGRATE_(CONNECTED|CONNECT_ERROR) or a timeout.
(3) spice_server_migrate_end: tell client migration it can switch to the target - send
    SPICE_MSG_MAIN_MIGRATE_END.
(4) client cleans up all data related to the connection to the source and switches to the target.
    It sends SPICE_MSGC_MAIN_MIGRATE_END.

migration target side
---------------------
(1) the server identifies itself as a migraiton target since the client is linked with (connection_id != 0)
(2) server doesn't start the channels' logic (channel->link) till it receives SPICE_MSGC_MAIN_MIGRATE_END
    from the client.

*   After migration starts, the target qemu is blocked and cannot accept new spice client
    connections. Thus, we trigger the connection to the target upon client_migrate_info
    command.

1 files changed, 9 insertions, 0 deletions

diff --git a/server/reds.c b/server/reds.c
index f082c531..9a983f8c 100644
--- a/server/reds.c
+++ b/server/reds.c
@@ -4854,6 +4854,15 @@ SPICE_GNUC_VISIBLE int spice_server_set_agent_copypaste(SpiceServer *s, int enab
     return 0;
 }
 
+/* semi-seamless client migration */
+SPICE_GNUC_VISIBLE int spice_server_migrate_connect(SpiceServer *s, const char* dest,
+                                                    int port, int secure_port,
+                                                    const char* cert_subject)
+{
+    red_printf("not implemented yet");
+    return 0;
+}
+
 SPICE_GNUC_VISIBLE int spice_server_migrate_info(SpiceServer *s, const char* dest,
                                           int port, int secure_port,
                                           const char* cert_subject)