[PATCH 0/13] Implement dumping udp sockets via sock_diag netlink

Hi!

This is an extension of inet_diag module and the new udp_diag one. Plus
the patch for iproute's ss to dump udp sockets via netlink (applies on top
of previous patch for new NETLINK_SOCK_DIAG API [1]).

The overall idea is:

Patch the inet_diag module so that the protocol level handlers are called
indirectly from the very beginning, not just for getting the tcp_info bits.
Implement the udp_diag module that provides callbacks for IPPROTO_UDP and
IPPROTO_UDPLITE protocols.

The existing inet request packet (inet_diag_req) format used to request for
TCP/DCCP sockets is used for UDP socket as well, although not all the state
bits matter for UDP.

When sending back the reply the existing format (inet_diag_message) is used
as well. Some bits on this struct are meaningless for UDP, but I hope that
setting these to 0 and wasting some space on reply skb worth the saved amount
of new code on both -- the kernel side and the userspace side (i.e. ss tool).
The data that is stored in an nl attribute but doesn't exist for UDP is just
not provided.

Signed-off-by: Pavel Emelyanov <redacted>

[1] http://www.spinics.net/lists/netdev/msg182467.html