From 81aded24675ebda5de8a68843250ad15584ac38a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 15 Jun 2012 14:54:11 -0700 Subject: ipv6: Handle PMTU in ICMP error handlers. One tricky issue on the ipv6 side vs. ipv4 is that the ICMP callouts to handle the error pass the 32-bit info cookie in network byte order whereas ipv4 passes it around in host byte order. Like the ipv4 side, we have two helper functions. One for when we have a socket context and one for when we do not. ip6ip6 tunnels are not handled here, because they handle PMTU events by essentially relaying another ICMP packet-too-big message back to the original sender. This patch allows us to get rid of rt6_do_pmtu_disc(). It handles all kinds of situations that simply cannot happen when we do the PMTU update directly using a fully resolved route. In fact, the "plen == 128" check in ip6_rt_update_pmtu() can very likely be removed or changed into a BUG_ON() check. We should never have a prefixed ipv6 route when we get there. Another piece of strange history here is that TCP and DCCP, unlike in ipv4, never invoke the update_pmtu() method from their ICMP error handlers. This is incredibly astonishing since this is the context where we have the most accurate context in which to make a PMTU update, namely we have a fully connected socket and associated cached socket route. Signed-off-by: David S. Miller --- net/dccp/ipv6.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/dccp') diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index fa9512d86f3b..9991be083ad0 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -165,6 +165,8 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, } else dst_hold(dst); + dst->ops->update_pmtu(dst, ntohl(info)); + if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) { dccp_sync_mss(sk, dst_mtu(dst)); } /* else let the usual retransmit timer handle it */ -- cgit v1.2.3-59-g8ed1b