net/ipv6: Fix linklocal to global address with VRF

Example setup:
    host: ip -6 addr add dev eth1 2001:db8:104::4
           where eth1 is enslaved to a VRF

    switch: ip -6 ro add 2001:db8:104::4/128 dev br1
            where br1 only has an LLA

           ping6 2001:db8:104::4
           ssh   2001:db8:104::4

(NOTE: UDP works fine if the PKTINFO has the address set to the global
address and ifindex is set to the index of eth1 with a destination an
LLA).

For ICMP, icmp6_iif needs to be updated to check if skb->dev is an
L3 master. If it is then return the ifindex from rt6i_idev similar
to what is done for loopback.

For TCP, restore the original tcp_v6_iif definition which is needed in
most places and add a new tcp_v6_iif_l3_slave that considers the
l3_slave variability. This latter check is only needed for socket
lookups.

Fixes: 9ff74384600a ("net: vrf: Handle ipv6 multicast and link-local addresses")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7efa9fd7e109..03e6b7a2bc53 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -938,7 +938,8 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
                                            &tcp_hashinfo, NULL, 0,
                                            &ipv6h->saddr,
                                            th->source, &ipv6h->daddr,
-                                           ntohs(th->source), tcp_v6_iif(skb),
+                                           ntohs(th->source),
+                                           tcp_v6_iif_l3_slave(skb),
                                            tcp_v6_sdif(skb));
                 if (!sk1)
                         goto out;
@@ -1609,7 +1610,8 @@ do_time_wait:
                                             skb, __tcp_hdrlen(th),
                                             &ipv6_hdr(skb)->saddr, th->source,
                                             &ipv6_hdr(skb)->daddr,
-                                            ntohs(th->dest), tcp_v6_iif(skb),
+                                            ntohs(th->dest),
+                                            tcp_v6_iif_l3_slave(skb),
                                             sdif);
                 if (sk2) {
                         struct inet_timewait_sock *tw = inet_twsk(sk);