Dan Smith wrote:

This patch adds basic support for C/R of open INET sockets.  I think that
all the important bits of the TCP and ICSK socket structures is saved,
but I think there is still some additional IPv6 stuff that needs to be
handled.

With this patch applied, the following script can be used to demonstrate
the functionality:

  https://lists.linux-foundation.org/pipermail/containers/2009-October/021239.html

It shows that this enables migration of a sendmail process with open
connections from one machine to another without dropping.

We probably need comments from the netdev people about the quality of
sanity checking we do on the values in the ckpt_hdr_socket_inet
structure on restart.

Note that this still doesn't address lingering sockets yet.

Changes in v3:
 - Prevent restart from allowing a bind on a <1024 port unless the
   user is granted that capability
 - Add some sanity checking in the inet_precheck() function to make sure
   the values read from the checkpoint image are within acceptable ranges
 - Check the result of sock_restore_header_info() and fail if needed

Changes in v2:
 - Restore saddr, rcv_saddr, daddr, sport, and dport from the sockaddr
   structure instead of saving them separately
 - Fix 'sock' naming in sock_cptrst()
 - Don't take the queue lock before skb_queue_tail() since it is
   done for us
 - Allow "listen only" restore behavior if RESTART_SOCK_LISTENONLY
   flag is specified on sys_restart()
 - Pull the implementation of the list of listening sockets back into
   this patch
 - Fix dangling printk
 - Add some comments around the parent/child restore logic

Cc: netdev@vger.kernel.org
Cc: Oren Laadan <redacted>
Cc: John Dykstra <redacted>
Signed-off-by: Dan Smith <redacted>
---

This looks good:
Acked-by: Oren Laadan <redacted>

I still want to move this to right under the restart-specific fields:
	struct list_head listen_sockets;/* listening parent sockets */

Also, I'm looking for a better name for RESTART_SOCK_LISTENONLY
(it isn't listen only, udp sockets are preserved...), something
that will convey the idea that we drop old connections,
perhaps:
	RESTART_NET_RESET
	RESTART_CONN_RESET
	RESTART_DROPCONN
?

Oren.