diff options
authorVinay K Nallamothu <nvinay@juniper.net>2019-03-19 22:41:18 +0000
committerDavid S. Miller <davem@davemloft.net>2019-03-19 16:00:22 -0700
commitf84532ce5887dac2ef67498b897a8713793eebde (patch)
parent3c515: fix integer overflow warning (diff)
mpls: Fix 6PE forwarding
This patch adds support for 6PE (RFC 4798) which uses IPv4-mapped IPv6 nexthop to connect IPv6 islands over IPv4 only MPLS network core. Prior to this fix, to find the link-layer destination mac address, 6PE enabled host/router was sending IPv6 ND requests for IPv4-mapped IPv6 nexthop address over the interface facing the IPv4 only core which wouldn't success as the core is IPv6 free. This fix changes that behavior on 6PE host to treat the nexthop as IPv4 address and send ARP requests whenever the next-hop address is an IPv4-mapped IPv6 address. Below topology illustrates the issue and how the patch addresses it. abcd:: (lo) abcd:: (lo) R0 (PE/host)------------------------R1--------------------------------R2 (PE/host) <--- IPv4 MPLS core ---> <------ IPv4 MPLS core --------> eth1 eth2 eth3 eth4 ffff:: ffff:: <------------------IPv6 MPLS tunnel ----------------------> R0 and R2 act as 6PE routers of IPv6 islands. R1 is IPv4 only with MPLS tunnels between R0,R1 and R1,R2. docker exec r0 ip -f inet6 route add abcd:: nexthop encap mpls 100 via ::ffff: dev eth1 docker exec r2 ip -f inet6 route add abcd:: nexthop encap mpls 200 via ::ffff: dev eth4 docker exec r1 ip -f mpls route add 100 via inet dev eth3 docker exec r1 ip -f mpls route add 200 via inet dev eth2 With the change, when R0 sends an IPv6 packet over MPLS tunnel to abcd::, using ::ffff: as the nexthop, it does neighbor discovery for Signed-off-by: Vinay K Nallamothu <nvinay@juniper.net> Tested-by: Avinash Lingala <ar977m@att.com> Tested-by: Aravind Srinivas Srinivasa Prabhakar <aprabh@juniper.net> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 9 insertions, 3 deletions
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index dda8930f20e7..f3a8557494d6 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -140,9 +140,15 @@ static int mpls_xmit(struct sk_buff *skb)
if (rt)
err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
- else if (rt6)
- err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
- skb);
+ else if (rt6) {
+ if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
+ /* 6PE (RFC 4798) */
+ err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3],
+ skb);
+ } else
+ err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
+ skb);
+ }
if (err)
net_dbg_ratelimited("%s: packet transmission failed: %d\n",
__func__, err);