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tcp: inherit listener congestion control for passive cnx

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Rick Jones reported that TCP_CONGESTION sockopt performed on a listener
was ignored for its children sockets : right after accept() the
congestion control for new socket is the system default one.

This seems an oversight of the initial design (quoted from Stephen)

Based on prior investigation and patch from Rick.

Reported-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Yuchung Cheng <ycheng@google.com>
Tested-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2011-11-30 01:02:41 +00:00 committed by David S. Miller
parent de56566404
commit d8a6e65f8b
3 changed files with 7 additions and 1 deletions
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3
Documentation/networking/ip-sysctl.txt
View file

@ -175,6 +175,9 @@ tcp_congestion_control - STRING
connections. The algorithm "reno" is always available, but
additional choices may be available based on kernel configuration.
Default is set as part of kernel configuration.
For passive connections, the listener congestion control choice
is inherited.
[see setsockopt(listenfd, SOL_TCP, TCP_CONGESTION, "name" ...) ]
tcp_cookie_size - INTEGER
Default size of TCP Cookie Transactions (TCPCT) option, that may be

1
net/ipv4/tcp_ipv4.c
View file

@ -1511,6 +1511,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
return NULL;
put_and_exit:
tcp_clear_xmit_timers(newsk);
tcp_cleanup_congestion_control(newsk);
bh_unlock_sock(newsk);
sock_put(newsk);
goto exit;

4
net/ipv4/tcp_minisocks.c
View file

@ -495,7 +495,9 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
newtp->frto_counter = 0;
newtp->frto_highmark = 0;
newicsk->icsk_ca_ops = &tcp_init_congestion_ops;
if (newicsk->icsk_ca_ops != &tcp_init_congestion_ops &&
!try_module_get(newicsk->icsk_ca_ops->owner))
newicsk->icsk_ca_ops = &tcp_init_congestion_ops;
tcp_set_ca_state(newsk, TCP_CA_Open);
tcp_init_xmit_timers(newsk);