diff options
| author | Eric Dumazet <edumazet@google.com> | 2016-10-26 09:27:57 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-01-11 02:04:47 +0000 |
| commit | 54d013527df9042787ede28b13f40446c1997102 (patch) | |
| tree | d6d0fd730a7571ec2e35c179e9d4ae9ca9e96e97 /net/ipv6/tcp_ipv6.c | |
| parent | 82967f98bc8dfff2dfdf4359aabab3e4e92f17e8 (diff) | |
tcp/dccp: drop SYN packets if accept queue is full
commit 5ea8ea2cb7f1d0db15762c9b0bb9e7330425a071 upstream.
Per listen(fd, backlog) rules, there is really no point accepting a SYN,
sending a SYNACK, and dropping the following ACK packet if accept queue
is full, because application is not draining accept queue fast enough.
This behavior is fooling TCP clients that believe they established a
flow, while there is nothing at server side. They might then send about
10 MSS (if using IW10) that will be dropped anyway while server is under
stress.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[bwh: Backported to 3.16: Apply TCP changes in both tcp_ipv4.c and tcp_ipv6.c]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'net/ipv6/tcp_ipv6.c')
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 4370371e0aa6..0eb27c808bfa 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1009,7 +1009,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) goto drop; } - if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) { + if (sk_acceptq_is_full(sk)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); goto drop; } |