What about something like this:
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ed44663..21b4102 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1394,6 +1394,19 @@ static void ip6_rt_update_pmtu(struct dst_entry
*dst, struct sock *sk,
__ip6_rt_update_pmtu(dst, sk, skb ? ipv6_hdr(skb) : NULL, mtu);
}
+static void ip6_fill_in_flow(struct flowi6 *fl6, struct net *net,
+ struct sk_buff *skb, int oif, u32 mark)
+{
+ const struct ipv6hdr *iph = (struct ipv6hdr *) skb->data;
+
+ memset(fl6, 0, sizeof(fl6));
+ fl6->flowi6_oif = oif;
+ fl6->flowi6_mark = mark ? mark : IP6_REPLY_MARK(net, skb->mark);
+ fl6->daddr = iph->daddr;
+ fl6->saddr = iph->saddr;
+ fl6->flowlabel = ip6_flowinfo(iph);
+}
+
void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
int oif, u32 mark)
{
@@ -1401,13 +1414,7 @@ void ip6_update_pmtu(struct sk_buff *skb,
struct net *net, __be32 mtu,
struct dst_entry *dst;
struct flowi6 fl6;
- memset(&fl6, 0, sizeof(fl6));
- fl6.flowi6_oif = oif;
- fl6.flowi6_mark = mark ? mark : IP6_REPLY_MARK(net, skb->mark);
- fl6.daddr = iph->daddr;
- fl6.saddr = iph->saddr;
- fl6.flowlabel = ip6_flowinfo(iph);
-
+ ip6_fill_in_flow(&fl6, net, skb, oif, mark);
dst = ip6_route_output(net, NULL, &fl6);
if (!dst->error)
__ip6_rt_update_pmtu(dst, NULL, iph, ntohl(mtu));
@@ -1417,8 +1424,22 @@ EXPORT_SYMBOL_GPL(ip6_update_pmtu);
void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu)
{
- ip6_update_pmtu(skb, sock_net(sk), mtu,
+ struct ipv6_pinfo *np = inet6_sk(sk);
+ struct dst_entry *dst_new;
+ struct flowi6 fl6;
+ struct net *net = sock_net(sk);
+
+ ip6_update_pmtu(skb, net, mtu,
+ sk->sk_bound_dev_if, sk->sk_mark);
+
+ if (sk->sk_state == TCP_ESTABLISHED &&
+ !sk_dst_check(sk, np->dst_cookie)) {
+ ip6_fill_in_flow(&fl6, net, skb,
sk->sk_bound_dev_if, sk->sk_mark);
+ dst_new = ip6_route_output(net, NULL, &fl6);
+ if (!IS_ERR(dst_new))
+ ip6_dst_store(sk, dst_new, NULL, NULL);
+ }
}
EXPORT_SYMBOL_GPL(ip6_sk_update_pmtu);
Thanks.
Wei
On Tue, Mar 22, 2016 at 4:36 PM, Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Tue, 2016-03-22 at 13:13 -0700, Cong Wang wrote:
>> On Tue, Mar 22, 2016 at 11:03 AM, Wei Wang <tracyw...@gmail.com> wrote:
>> > Thanks Martin and Cong.
>> >
>> > I guess then we are going with the following fix in ip6_sk_update_pmtu():
>> > 1. call ip6_upate_pmtu() as it is
>> > 2. do a dst_check()
>> > 3. re-lookup() if it is invalid
>> > 4. and then do a ip6_dst_store()/dst_set
>>
>> Exactly, please try the attached patch. Note I did nothing more than a
>> compile test.
>>
>> Does it make sense to you now?
>
>
> Hard to reply on your patch as it was not inlined.
>
> 1) Lot of code duplication, for some reason I do not yet understand.
>
> ip6_sk_update_pmtu() and ip6_update_pmtu() will basically do the same
> thing...
>
> 2)
>
> + if (sk->sk_state == TCP_ESTABLISHED)
> + ip6_dst_store(sk, dst, &iph->daddr, &iph->saddr);
> +out:
>
>
> ip6_dst_store() will do :
>
> np->daddr_cache = daddr; (&iph->daddr)
> np->saddr_cache = saddr; (&iph->saddr)
>
> So when skb is freed, daddr_cache & saddr_cache point to freed data.
>
>
>
>
