target/linux/generic/backport-4.9/096-v4.20-netfilter-ipv6-Preserve-link-scope-traffic-original-.patch

   1 From 508b09046c0f21678652fb66fd1e9959d55591d2 Mon Sep 17 00:00:00 2001
   2 From: Alin Nastac <alin.nastac@gmail.com>
   3 Date: Wed, 21 Nov 2018 14:00:30 +0100
   4 Subject: [PATCH] netfilter: ipv6: Preserve link scope traffic original oif
   5
   6 When ip6_route_me_harder is invoked, it resets outgoing interface of:
   7   - link-local scoped packets sent by neighbor discovery
   8   - multicast packets sent by MLD host
   9   - multicast packets send by MLD proxy daemon that sets outgoing
  10     interface through IPV6_PKTINFO ipi6_ifindex
  11
  12 Link-local and multicast packets must keep their original oif after
  13 ip6_route_me_harder is called.
  14
  15 Signed-off-by: Alin Nastac <alin.nastac@gmail.com>
  16 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  17 ---
  18  net/ipv6/netfilter.c | 3 ++-
  19  1 file changed, 2 insertions(+), 1 deletion(-)
  20
  21 --- a/net/ipv6/netfilter.c
  22 +++ b/net/ipv6/netfilter.c
  23 @@ -24,7 +24,8 @@ int ip6_route_me_harder(struct net *net,
  24         unsigned int hh_len;
  25         struct dst_entry *dst;
  26         struct flowi6 fl6 = {
  27 -               .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
  28 +               .flowi6_oif = skb->sk && skb->sk->sk_bound_dev_if ? skb->sk->sk_bound_dev_if :
  29 +                       rt6_need_strict(&iph->daddr) ? skb_dst(skb)->dev->ifindex : 0,
  30                 .flowi6_mark = skb->mark,
  31                 .daddr = iph->daddr,
  32                 .saddr = iph->saddr,