commit 58189ca7b27411c3dc9a5cb9eeee0906da684c59
author David Ahern <dsa@cumulusnetworks.com> Tue Sep 15 15:10:50 2015 -0700
committer David S. Miller <davem@davemloft.net> Thu Sep 17 16:36:34 2015 -0700
tree a193039f8278a234772c8a84fc21aaead1370457
parent d828755eae637c6ca39e30702e98abaf34cac146

net: Fix vti use case with oif in dst lookups

Steffen reported that the recent change to add oif to dst lookups breaks
the VTI use case. The problem is that with the oif set in the flow struct
the comparison to the nh_oif is triggered. Fix by splitting the
FLOWI_FLAG_VRFSRC into 2 flags -- one that triggers the vrf device cache
bypass (FLOWI_FLAG_VRFSRC) and another telling the lookup to not compare
nh oif (FLOWI_FLAG_SKIP_NH_OIF).

Fixes: 42a7b32b73d6 ("xfrm: Add oif to dst lookups")

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vrf.c

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index e7094fb..488c6f5 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -193,7 +193,8 @@
 		.flowi4_oif = vrf_dev->ifindex,
 		.flowi4_iif = LOOPBACK_IFINDEX,
 		.flowi4_tos = RT_TOS(ip4h->tos),
-		.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_VRFSRC,
+		.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_VRFSRC |
+				FLOWI_FLAG_SKIP_NH_OIF,
 		.daddr = ip4h->daddr,
 	};
 

include/net/flow.h

diff --git a/include/net/flow.h b/include/net/flow.h
index acd6a09..9b85db8 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -35,6 +35,7 @@
 #define FLOWI_FLAG_ANYSRC		0x01
 #define FLOWI_FLAG_KNOWN_NH		0x02
 #define FLOWI_FLAG_VRFSRC		0x04
+#define FLOWI_FLAG_SKIP_NH_OIF		0x08
 	__u32	flowic_secid;
 	struct flowi_tunnel flowic_tun_key;
 };

include/net/route.h

diff --git a/include/net/route.h b/include/net/route.h
index cc61cb9..f46af25 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -255,7 +255,7 @@
 		flow_flags |= FLOWI_FLAG_ANYSRC;
 
 	if (netif_index_is_vrf(sock_net(sk), oif))
-		flow_flags |= FLOWI_FLAG_VRFSRC;
+		flow_flags |= FLOWI_FLAG_VRFSRC | FLOWI_FLAG_SKIP_NH_OIF;
 
 	flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 			   protocol, flow_flags, dst, src, dport, sport);

net/ipv4/fib_trie.c

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 26d6ffb..6c2af79 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1426,7 +1426,7 @@
 			    nh->nh_flags & RTNH_F_LINKDOWN &&
 			    !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
 				continue;
-			if (!(flp->flowi4_flags & FLOWI_FLAG_VRFSRC)) {
+			if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
 				if (flp->flowi4_oif &&
 				    flp->flowi4_oif != nh->nh_oif)
 					continue;

net/ipv4/udp.c

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index c0a15e7..f7d1d5e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1024,7 +1024,8 @@
 		if (netif_index_is_vrf(net, ipc.oif)) {
 			flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
 					   RT_SCOPE_UNIVERSE, sk->sk_protocol,
-					   (flow_flags | FLOWI_FLAG_VRFSRC),
+					   (flow_flags | FLOWI_FLAG_VRFSRC |
+					    FLOWI_FLAG_SKIP_NH_OIF),
 					   faddr, saddr, dport,
 					   inet->inet_sport);
 

net/ipv4/xfrm4_policy.c

diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index bb919b2..c10a9ee 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -33,6 +33,8 @@
 	if (saddr)
 		fl4->saddr = saddr->a4;
 
+	fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
+
 	rt = __ip_route_output_key(net, fl4);
 	if (!IS_ERR(rt))
 		return &rt->dst;