diff options
| author | Yuchung Cheng <ycheng@google.com> | 2019-01-16 15:05:32 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-17 15:12:26 -0800 |
| commit | 01a523b071618abbc634d1958229fe3bd2dfa5fa (patch) | |
| tree | 043afd9aa6674b92fb0bd7d6c97eb7220df3ba0b /net/ipv4/tcp_timer.c | |
| parent | c7d13c8faa74f4e8ef191f88a252cefab6805b38 (diff) | |
tcp: create a helper to model exponential backoff
Create a helper to model TCP exponential backoff for the next patch.
This is pure refactor w no behavior change.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_timer.c')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 074de38bafbd..bcc2f5783e57 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -159,7 +159,20 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); } - +static unsigned int tcp_model_timeout(struct sock *sk, + unsigned int boundary, + unsigned int rto_base) +{ + unsigned int linear_backoff_thresh, timeout; + + linear_backoff_thresh = ilog2(TCP_RTO_MAX / rto_base); + if (boundary <= linear_backoff_thresh) + timeout = ((2 << boundary) - 1) * rto_base; + else + timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + + (boundary - linear_backoff_thresh) * TCP_RTO_MAX; + return jiffies_to_msecs(timeout); +} /** * retransmits_timed_out() - returns true if this connection has timed out * @sk: The current socket @@ -177,23 +190,15 @@ static bool retransmits_timed_out(struct sock *sk, unsigned int boundary, unsigned int timeout) { - const unsigned int rto_base = TCP_RTO_MIN; - unsigned int linear_backoff_thresh, start_ts; + unsigned int start_ts; if (!inet_csk(sk)->icsk_retransmits) return false; start_ts = tcp_sk(sk)->retrans_stamp; - if (likely(timeout == 0)) { - linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base); - - if (boundary <= linear_backoff_thresh) - timeout = ((2 << boundary) - 1) * rto_base; - else - timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + - (boundary - linear_backoff_thresh) * TCP_RTO_MAX; - timeout = jiffies_to_msecs(timeout); - } + if (likely(timeout == 0)) + timeout = tcp_model_timeout(sk, boundary, TCP_RTO_MIN); + return (s32)(tcp_time_stamp(tcp_sk(sk)) - start_ts - timeout) >= 0; } |