diff options
Diffstat (limited to 'sys/netinet/cc')
| -rw-r--r-- | sys/netinet/cc/cc_newreno.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/sys/netinet/cc/cc_newreno.c b/sys/netinet/cc/cc_newreno.c index e383510..511186a 100644 --- a/sys/netinet/cc/cc_newreno.c +++ b/sys/netinet/cc/cc_newreno.c @@ -216,15 +216,28 @@ newreno_post_recovery(struct cc_var *ccv) void newreno_after_idle(struct cc_var *ccv) { + int rw; + /* - * We have been idle for "a while" and no acks are expected to clock out - * any data we send -- slow start to get ack "clock" running again. + * If we've been idle for more than one retransmit timeout the old + * congestion window is no longer current and we have to reduce it to + * the restart window before we can transmit again. + * + * The restart window is the initial window or the last CWND, whichever + * is smaller. + * + * This is done to prevent us from flooding the path with a full CWND at + * wirespeed, overloading router and switch buffers along the way. + * + * See RFC5681 Section 4.1. "Restarting Idle Connections". */ if (V_tcp_do_rfc3390) - CCV(ccv, snd_cwnd) = min(4 * CCV(ccv, t_maxseg), + rw = min(4 * CCV(ccv, t_maxseg), max(2 * CCV(ccv, t_maxseg), 4380)); else - CCV(ccv, snd_cwnd) = CCV(ccv, t_maxseg) * 2; + rw = CCV(ccv, t_maxseg) * 2; + + CCV(ccv, snd_cwnd) = min(rw, CCV(ccv, snd_cwnd)); } |
