diff options
| author | Damian Lukowski <damian@tvk.rwth-aachen.de> | 2009-12-07 06:06:16 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-12-08 20:56:11 -0800 |
| commit | 2f7de5710a4d394920405febc2a9937c69e16dda (patch) | |
| tree | 8f038451b643f68ab399009e769a74678feb5546 /net | |
| parent | 07f29bc5bbae4e53e982ab956fed7207990a7786 (diff) | |
| download | lwn-2f7de5710a4d394920405febc2a9937c69e16dda.tar.gz lwn-2f7de5710a4d394920405febc2a9937c69e16dda.zip | |
tcp: Stalling connections: Move timeout calculation routine
This patch moves retransmits_timed_out() from include/net/tcp.h
to tcp_timer.c, where it is used.
Reported-by: Frederic Leroy <fredo@starox.org>
Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 8353a538cd4c..8816a20c2597 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -132,6 +132,35 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) } } +/* This function calculates a "timeout" which is equivalent to the timeout of a + * TCP connection after "boundary" unsucessful, exponentially backed-off + * retransmissions with an initial RTO of TCP_RTO_MIN. + */ +static bool retransmits_timed_out(struct sock *sk, + unsigned int boundary) +{ + unsigned int timeout, linear_backoff_thresh; + unsigned int start_ts; + + if (!inet_csk(sk)->icsk_retransmits) + return false; + + if (unlikely(!tcp_sk(sk)->retrans_stamp)) + start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when; + else + start_ts = tcp_sk(sk)->retrans_stamp; + + linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN); + + if (boundary <= linear_backoff_thresh) + timeout = ((2 << boundary) - 1) * TCP_RTO_MIN; + else + timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN + + (boundary - linear_backoff_thresh) * TCP_RTO_MAX; + + return (tcp_time_stamp - start_ts) >= timeout; +} + /* A write timeout has occurred. Process the after effects. */ static int tcp_write_timeout(struct sock *sk) { |