From: Eric Dumazet <redacted>
Date: Wed, 29 Nov 2017 17:43:57 -0800

From: Eric Dumazet <edumazet@google.com>

tcp_v6_send_reset() expects to receive an skb with skb->cb[] layout as
used in TCP stack.
MD5 lookup uses tcp_v6_iif() and tcp_v6_sdif() and thus
TCP_SKB_CB(skb)->header.h6

This patch probably fixes RST packets sent on behalf of a timewait md5
ipv6 socket.

Before Florian patch, tcp_v6_restore_cb() was needed before jumping to
no_tcp_socket label.

Fixes: 271c3b9b7bda ("tcp: honour SO_BINDTODEVICE for TW_RST case too")
Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied and queued up for -stable.