diff options
| author | Yuchung Cheng <ycheng@google.com> | 2012-07-19 06:43:10 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-07-19 11:02:03 -0700 |
| commit | aab4874355679c70f93993cf3b3fd74643b9ac33 (patch) | |
| tree | 677d3faf161e39f9de18b5956e24cd746e73d996 /include/net | |
| parent | cf60af03ca4e71134206809ea892e49b92a88896 (diff) | |
| download | lwn-aab4874355679c70f93993cf3b3fd74643b9ac33.tar.gz lwn-aab4874355679c70f93993cf3b3fd74643b9ac33.zip | |
net-tcp: Fast Open client - detecting SYN-data drops
On paths with firewalls dropping SYN with data or experimental TCP options,
Fast Open connections will have experience SYN timeout and bad performance.
The solution is to track such incidents in the cookie cache and disables
Fast Open temporarily.
Since only the original SYN includes data and/or Fast Open option, the
SYN-ACK has some tell-tale sign (tcp_rcv_fastopen_synack()) to detect
such drops. If a path has recurring Fast Open SYN drops, Fast Open is
disabled for 2^(recurring_losses) minutes starting from four minutes up to
roughly one and half day. sendmsg with MSG_FASTOPEN flag will succeed but
it behaves as connect() then write().
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/tcp.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index c0258100d70c..e07878d246aa 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -409,9 +409,11 @@ extern bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, extern bool tcp_remember_stamp(struct sock *sk); extern bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw); extern void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, - struct tcp_fastopen_cookie *cookie); + struct tcp_fastopen_cookie *cookie, + int *syn_loss, unsigned long *last_syn_loss); extern void tcp_fastopen_cache_set(struct sock *sk, u16 mss, - struct tcp_fastopen_cookie *cookie); + struct tcp_fastopen_cookie *cookie, + bool syn_lost); extern void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst); extern void tcp_disable_fack(struct tcp_sock *tp); extern void tcp_close(struct sock *sk, long timeout); |