From 741a11d9e4103a8e1c590ef1280143fe654e4e33 Mon Sep 17 00:00:00 2001
From: David Ahern <dsa@cumulusnetworks.com>
Date: Mon, 28 Sep 2015 10:12:13 -0700
Subject: [PATCH] net: ipv6: Add RT6_LOOKUP_F_IFACE flag if oif is set
Wolfgang reported that IPv6 stack is ignoring oif in output route lookups:
With ipv6, ip -6 route get always returns the specific route.
$ ip -6 r
2001:db8:e2::1 dev enp2s0 proto kernel metric 256
2001:db8:e2::/64 dev enp2s0 metric 1024
2001:db8:e3::1 dev enp3s0 proto kernel metric 256
2001:db8:e3::/64 dev enp3s0 metric 1024
fe80::/64 dev enp3s0 proto kernel metric 256
default via 2001:db8:e3::255 dev enp3s0 metric 1024
$ ip -6 r get 2001:db8:e2::100
2001:db8:e2::100 from :: dev enp2s0 src 2001:db8:e3::1 metric 0
cache
$ ip -6 r get 2001:db8:e2::100 oif enp3s0
2001:db8:e2::100 from :: dev enp2s0 src 2001:db8:e3::1 metric 0
cache
The stack does consider the oif but a mismatch in rt6_device_match is not
considered fatal because RT6_LOOKUP_F_IFACE is not set in the flags.
Cc: Wolfgang Nothdurft <netdev@linux-dude.de>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/route.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f204089e854cf..cb32ce250db0c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1193,7 +1193,8 @@ struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
fl6->flowi6_iif = LOOPBACK_IFINDEX;
- if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr))
+ if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr) ||
+ fl6->flowi6_oif)
flags |= RT6_LOOKUP_F_IFACE;
if (!ipv6_addr_any(&fl6->saddr))
--
2.30.2