Merge branch 'net-l3mdev-Support-for-sockets-bound-to-enslaved-device'

Merge branch 'net-l3mdev-Support-for-sockets-bound-to-enslaved-device'

David Ahern says:

====================
net: l3mdev: Support for sockets bound to enslaved device

A missing piece to the VRF puzzle is the ability to bind sockets to
devices enslaved to a VRF. This patch set adds the enslaved device
index, sdif, to IPv4 and IPv6 socket lookups. The end result for users
is the following scope options for services:

1. "global" services - sockets not bound to any device

   Allows 1 service to work across all network interfaces with
   connected sockets bound to the VRF the connection originates
   (Requires net.ipv4.tcp_l3mdev_accept=1 for TCP and
    net.ipv4.udp_l3mdev_accept=1 for UDP)

2. "VRF" local services - sockets bound to a VRF

   Sockets work across all network interfaces enslaved to a VRF but
   are limited to just the one VRF.

3. "device" services - sockets bound to a specific network interface

   Service works only through the one specific interface.

v3
- convert __inet_lookup_established in dccp_v4_err; missed in v2

v2
- remove sk_lookup struct and add sdif as an argument to existing
  functions

Changes since RFC:
- no significant logic changes; mainly whitespace cleanups
====================

Signed-off-by: David S. Miller <davem@davemloft.net>