From 4bdc3d66147b3a623b32216a45431d0cff005f50 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 13 Oct 2015 17:12:54 -0700 Subject: tcp/dccp: fix behavior of stale SYN_RECV request sockets When a TCP/DCCP listener is closed, its pending SYN_RECV request sockets become stale, meaning 3WHS can not complete. But current behavior is wrong : incoming packets finding such stale sockets are dropped. We need instead to cleanup the request socket and perform another lookup : - Incoming ACK will give a RST answer, - SYN rtx might find another listener if available. - We expedite cleanup of request sockets and old listener socket. Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/tcp_ipv6.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'net/ipv6/tcp_ipv6.c') diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 2887c8474b65..7ce1c57199d1 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1363,6 +1363,7 @@ static int tcp_v6_rcv(struct sk_buff *skb) th = tcp_hdr(skb); hdr = ipv6_hdr(skb); +lookup: sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest, inet6_iif(skb)); if (!sk) @@ -1382,8 +1383,12 @@ process: reqsk_put(req); goto discard_it; } - if (sk->sk_state == TCP_LISTEN) + if (likely(sk->sk_state == TCP_LISTEN)) { nsk = tcp_check_req(sk, skb, req, false); + } else { + inet_csk_reqsk_queue_drop(sk, req); + goto lookup; + } if (!nsk) { reqsk_put(req); goto discard_it; -- cgit v1.2.3