diff options
| -rw-r--r-- | sys/netinet/tcp_output.c | 41 | ||||
| -rw-r--r-- | sys/netinet/tcp_var.h | 2 |
2 files changed, 28 insertions, 15 deletions
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index be8ea53..50d0ee6 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -140,7 +140,7 @@ tcp_output(struct tcpcb *tp) { struct socket *so = tp->t_inpcb->inp_socket; long len, recwin, sendwin; - int off, flags, error; + int off, flags, error, rw; struct mbuf *m; struct ip *ip = NULL; struct ipovly *ipov = NULL; @@ -176,23 +176,34 @@ tcp_output(struct tcpcb *tp) idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una); if (idle && ticks - tp->t_rcvtime >= tp->t_rxtcur) { /* - * 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. * - * Set the slow-start flight size depending on whether - * this is a local network or not. + * 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". */ - int ss = V_ss_fltsz; + if (V_tcp_do_rfc3390) + rw = min(4 * tp->t_maxseg, + max(2 * tp->t_maxseg, 4380)); #ifdef INET6 - if (isipv6) { - if (in6_localaddr(&tp->t_inpcb->in6p_faddr)) - ss = V_ss_fltsz_local; - } else -#endif /* INET6 */ - if (in_localaddr(tp->t_inpcb->inp_faddr)) - ss = V_ss_fltsz_local; - tp->snd_cwnd = tp->t_maxseg * ss; + else if ((isipv6 ? in6_localaddr(&tp->t_inpcb->in6p_faddr) : + in_localaddr(tp->t_inpcb->inp_faddr))) +#else + else if (in_localaddr(tp->t_inpcb->inp_faddr)) +#endif + rw = V_ss_fltsz_local * tp->t_maxseg; + else + rw = V_ss_fltsz * tp->t_maxseg; + + tp->snd_cwnd = min(rw, tp->snd_cwnd); } tp->t_flags &= ~TF_LASTIDLE; if (idle) { diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h index 7482277..b753e10 100644 --- a/sys/netinet/tcp_var.h +++ b/sys/netinet/tcp_var.h @@ -565,6 +565,7 @@ extern int tcp_log_in_vain; VNET_DECLARE(int, tcp_mssdflt); /* XXX */ VNET_DECLARE(int, tcp_minmss); VNET_DECLARE(int, tcp_delack_enabled); +VNET_DECLARE(int, tcp_do_rfc3390); VNET_DECLARE(int, tcp_do_newreno); VNET_DECLARE(int, path_mtu_discovery); VNET_DECLARE(int, ss_fltsz); @@ -575,6 +576,7 @@ VNET_DECLARE(int, ss_fltsz_local); #define V_tcp_mssdflt VNET(tcp_mssdflt) #define V_tcp_minmss VNET(tcp_minmss) #define V_tcp_delack_enabled VNET(tcp_delack_enabled) +#define V_tcp_do_rfc3390 VNET(tcp_do_rfc3390) #define V_tcp_do_newreno VNET(tcp_do_newreno) #define V_path_mtu_discovery VNET(path_mtu_discovery) #define V_ss_fltsz VNET(ss_fltsz) |
