From 1fdb515b3d9804ce6ad65f9fbb37e90c0e54c559 Mon Sep 17 00:00:00 2001 From: Georg Kohmann Date: Thu, 2 Aug 2018 13:56:58 +0200 Subject: [PATCH] ipv6: icmp: Updating pmtu for link local route When a ICMPV6_PKT_TOOBIG is received from a link local address the pmtu will be updated on a route with an arbitrary interface index. Subsequent packets sent back to the same link local address may therefore end up not considering the updated pmtu. Current behavior breaks TAHI v6LC4.1.4 Reduce PMTU On-link. Referring to RFC 1981: Section 3: "Note that Path MTU Discovery must be performed even in cases where a node "thinks" a destination is attached to the same link as itself. In a situation such as when a neighboring router acts as proxy [ND] for some destination, the destination can to appear to be directly connected but is in fact more than one hop away." Using the interface index from the incoming ICMPV6_PKT_TOOBIG when updating the pmtu. Signed-off-by: Georg Kohmann Signed-off-by: David S. Miller --- net/ipv6/icmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 00d159d431dc8..7f6b1f81c2007 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -92,7 +92,7 @@ static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, struct net *net = dev_net(skb->dev); if (type == ICMPV6_PKT_TOOBIG) - ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); + ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0, sock_net_uid(net, NULL)); else if (type == NDISC_REDIRECT) ip6_redirect(skb, net, skb->dev->ifindex, 0, sock_net_uid(net, NULL)); -- 2.39.5