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| author |   James Morris <jmorris@namei.org> | 2010-01-18 09:56:22 +1100 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2010-01-18 09:56:22 +1100 |
| commit | 2457552d1e6f3183cd93f81c49a8da5fe8bb0e42 (patch) | |
| tree | 7ca46caa910012d75617700e4083b3657053cb31 /net/ipv4/tcp_timer.c | |
| parent | selinux: change the handling of unknown classes (diff) | |
| parent | page allocator: update NR_FREE_PAGES only when necessary (diff) | |
| download | linux-dev-2457552d1e6f3183cd93f81c49a8da5fe8bb0e42.tar.xz linux-dev-2457552d1e6f3183cd93f81c49a8da5fe8bb0e42.zip | |
Merge branch 'master' into next
Diffstat (limited to 'net/ipv4/tcp_timer.c')
| -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) { |