| Message ID | 20180802115658.17084-1-geokohma@cisco.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | ipv6: icmp: Updating pmtu for link local route | expand |
From: Georg Kohmann <geokohma@cisco.com> Date: Thu, 2 Aug 2018 13:56:58 +0200 > 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 <geokohma@cisco.com> Applied, thanks Georg.
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 3ae2fbe..211db37 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));
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 <geokohma@cisco.com> --- net/ipv6/icmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)