Re: [PATCH] ipv6: Fix the pmtu path for connected UDP socket

[David Miller]

From: Wei Wang <wei...@google.com>
Date: Wed,  2 Mar 2016 11:19:21 -0800

> @@ -566,7 +567,16 @@ void __udp6_lib_err(struct sk_buff *skb, struct 
> inet6_skb_parm *opt,
>       if (type == ICMPV6_PKT_TOOBIG) {
>               if (!ip6_sk_accept_pmtu(sk))
>                       goto out;
> -             ip6_sk_update_pmtu(skb, sk, info);
> +             bh_lock_sock(sk);
> +             if (sk->sk_state == TCP_ESTABLISHED &&
> +                 !sock_owned_by_user(sk) &&
> +                 ipv6_addr_equal(saddr, &sk->sk_v6_rcv_saddr) &&
> +                 ipv6_addr_equal(daddr, &sk->sk_v6_daddr) &&
> +                 uh->dest == sk->sk_dport)
> +                     inet6_csk_update_pmtu(sk, ntohl(info));

If I apply this patch it will hide a bug.

Why isn't ip6_sk_update_pmtu() matching the same route as the
one attached to the socket?

I'd prefer you figure out what part of the lookup key used is
wrong, and fix that instead.

Thanks.