From 4df98e76cde7c64b5606d82584c65dda4151bd6a Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Mon, 16 Dec 2013 12:36:44 +0100 Subject: [PATCH] ipv6: pmtudisc setting not respected with UFO/CORK Sockets marked with IPV6_PMTUDISC_PROBE (or later IPV6_PMTUDISC_INTERFACE) don't respect this setting when the outgoing interface supports UFO. We had the same problem in IPv4, which was fixed in commit daba287b299ec7a2c61ae3a714920e90e8396ad5 ("ipv4: fix DO and PROBE pmtu mode regarding local fragmentation with UFO/CORK"). Also IPV6_DONTFRAG mode did not care about already corked data, thus it may generate a fragmented frame even if this socket option was specified. It also did not care about the length of the ipv6 header and possible options. In the error path allow the user to receive the pmtu notifications via both, rxpmtu method or error queue. The user may opted in for both, so deliver the notification to both error handlers (the handlers check if the error needs to be enqueued). Also report back consistent pmtu values when sending on an already cork-appended socket. Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv6/ip6_output.c | 36 +++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4acdb63495db..e6f931997996 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1193,11 +1193,35 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len + (opt ? opt->opt_nflen : 0); - maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); + maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - + sizeof(struct frag_hdr); if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { - if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { - ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen); + unsigned int maxnonfragsize, headersize; + + headersize = sizeof(struct ipv6hdr) + + (opt ? opt->tot_len : 0) + + (dst_allfrag(&rt->dst) ? + sizeof(struct frag_hdr) : 0) + + rt->rt6i_nfheader_len; + + maxnonfragsize = (np->pmtudisc >= IPV6_PMTUDISC_DO) ? + mtu : sizeof(struct ipv6hdr) + IPV6_MAXPLEN; + + /* dontfrag active */ + if ((cork->length + length > mtu - headersize) && dontfrag && + (sk->sk_protocol == IPPROTO_UDP || + sk->sk_protocol == IPPROTO_RAW)) { + ipv6_local_rxpmtu(sk, fl6, mtu - headersize + + sizeof(struct ipv6hdr)); + goto emsgsize; + } + + if (cork->length + length > maxnonfragsize - headersize) { +emsgsize: + ipv6_local_error(sk, EMSGSIZE, fl6, + mtu - headersize + + sizeof(struct ipv6hdr)); return -EMSGSIZE; } } @@ -1222,12 +1246,6 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, * --yoshfuji */ - if ((length > mtu) && dontfrag && (sk->sk_protocol == IPPROTO_UDP || - sk->sk_protocol == IPPROTO_RAW)) { - ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen); - return -EMSGSIZE; - } - skb = skb_peek_tail(&sk->sk_write_queue); cork->length += length; if (((length > mtu) ||