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/ipv6/icmp.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'net/ipv6/icmp.c') diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index ed89bba745a1..5247d5c211f9 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -649,7 +649,6 @@ static int icmpv6_rcv(struct sk_buff *skb) struct net_device *dev = skb->dev; struct inet6_dev *idev = __in6_dev_get(dev); const struct in6_addr *saddr, *daddr; - const struct ipv6hdr *orig_hdr; struct icmp6hdr *hdr; u8 type; @@ -661,7 +660,7 @@ static int icmpv6_rcv(struct sk_buff *skb) XFRM_STATE_ICMP)) goto drop_no_count; - if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr))) + if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) goto drop_no_count; nh = skb_network_offset(skb); @@ -722,9 +721,6 @@ static int icmpv6_rcv(struct sk_buff *skb) if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) goto discard_it; hdr = icmp6_hdr(skb); - orig_hdr = (struct ipv6hdr *) (hdr + 1); - rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev, - ntohl(hdr->icmp6_mtu)); /* * Drop through to notify -- cgit v1.2.3