diff options
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 59110caeb07..bc5432e3c77 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -275,12 +275,15 @@ failure: EXPORT_SYMBOL(tcp_v4_connect); /* - * This routine does path mtu discovery as defined in RFC1191. + * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. + * It can be called through tcp_release_cb() if socket was owned by user + * at the time tcp_v4_err() was called to handle ICMP message. */ -static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu) +static void tcp_v4_mtu_reduced(struct sock *sk) { struct dst_entry *dst; struct inet_sock *inet = inet_sk(sk); + u32 mtu = tcp_sk(sk)->mtu_info; /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs * send out by Linux are always <576bytes so they should go through @@ -373,8 +376,12 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) bh_lock_sock(sk); /* If too many ICMPs get dropped on busy * servers this needs to be solved differently. + * We do take care of PMTU discovery (RFC1191) special case : + * we can receive locally generated ICMP messages while socket is held. */ - if (sock_owned_by_user(sk)) + if (sock_owned_by_user(sk) && + type != ICMP_DEST_UNREACH && + code != ICMP_FRAG_NEEDED) NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); if (sk->sk_state == TCP_CLOSE) @@ -409,8 +416,11 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) goto out; if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ + tp->mtu_info = info; if (!sock_owned_by_user(sk)) - do_pmtu_discovery(sk, iph, info); + tcp_v4_mtu_reduced(sk); + else + set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags); goto out; } @@ -2596,6 +2606,7 @@ struct proto tcp_prot = { .sendpage = tcp_sendpage, .backlog_rcv = tcp_v4_do_rcv, .release_cb = tcp_release_cb, + .mtu_reduced = tcp_v4_mtu_reduced, .hash = inet_hash, .unhash = inet_unhash, .get_port = inet_csk_get_port, |