Author: tuexen Date: Fri Jan 25 13:57:09 2019 New Revision: 343428 URL: https://svnweb.freebsd.org/changeset/base/343428
Log: Fix a bug in the restart window computation of TCP New Reno When implementing support for IW10, an update in the computation of the restart window used after an idle phase was missed. To minimize code duplication, implement the logic in tcp_compute_initwnd() and call it. This fixes a bug in NewReno, which was not aware of IW10. Submitted by: Richard Scheffenegger Reviewed by: tuexen@ MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D18940 Modified: head/sys/netinet/cc/cc_newreno.c head/sys/netinet/tcp_input.c head/sys/netinet/tcp_stacks/rack.c head/sys/netinet/tcp_var.h Modified: head/sys/netinet/cc/cc_newreno.c ============================================================================== --- head/sys/netinet/cc/cc_newreno.c Fri Jan 25 13:48:40 2019 (r343427) +++ head/sys/netinet/cc/cc_newreno.c Fri Jan 25 13:57:09 2019 (r343428) @@ -199,7 +199,7 @@ newreno_ack_received(struct cc_var *ccv, uint16_t type static void newreno_after_idle(struct cc_var *ccv) { - int rw; + uint32_t rw; /* * If we've been idle for more than one retransmit timeout the old @@ -214,11 +214,7 @@ newreno_after_idle(struct cc_var *ccv) * * See RFC5681 Section 4.1. "Restarting Idle Connections". */ - if (V_tcp_do_rfc3390) - rw = min(4 * CCV(ccv, t_maxseg), - max(2 * CCV(ccv, t_maxseg), 4380)); - else - rw = CCV(ccv, t_maxseg) * 2; + rw = tcp_compute_initwnd(tcp_maxseg(ccv->ccvc.tcp)); CCV(ccv, snd_cwnd) = min(rw, CCV(ccv, snd_cwnd)); } Modified: head/sys/netinet/tcp_input.c ============================================================================== --- head/sys/netinet/tcp_input.c Fri Jan 25 13:48:40 2019 (r343427) +++ head/sys/netinet/tcp_input.c Fri Jan 25 13:57:09 2019 (r343428) @@ -371,31 +371,14 @@ cc_conn_init(struct tcpcb *tp) /* * Set the initial slow-start flight size. * - * RFC5681 Section 3.1 specifies the default conservative values. - * RFC3390 specifies slightly more aggressive values. - * RFC6928 increases it to ten segments. - * Support for user specified value for initial flight size. - * * If a SYN or SYN/ACK was lost and retransmitted, we have to * reduce the initial CWND to one segment as congestion is likely * requiring us to be cautious. */ if (tp->snd_cwnd == 1) tp->snd_cwnd = maxseg; /* SYN(-ACK) lost */ - else if (V_tcp_initcwnd_segments) - tp->snd_cwnd = min(V_tcp_initcwnd_segments * maxseg, - max(2 * maxseg, V_tcp_initcwnd_segments * 1460)); - else if (V_tcp_do_rfc3390) - tp->snd_cwnd = min(4 * maxseg, max(2 * maxseg, 4380)); - else { - /* Per RFC5681 Section 3.1 */ - if (maxseg > 2190) - tp->snd_cwnd = 2 * maxseg; - else if (maxseg > 1095) - tp->snd_cwnd = 3 * maxseg; - else - tp->snd_cwnd = 4 * maxseg; - } + else + tp->snd_cwnd = tcp_compute_initwnd(maxseg); if (CC_ALGO(tp)->conn_init != NULL) CC_ALGO(tp)->conn_init(tp->ccv); @@ -3817,4 +3800,31 @@ tcp_compute_pipe(struct tcpcb *tp) return (tp->snd_max - tp->snd_una + tp->sackhint.sack_bytes_rexmit - tp->sackhint.sacked_bytes); +} + +uint32_t +tcp_compute_initwnd(uint32_t maxseg) +{ + /* + * Calculate the Initial Window, also used as Restart Window + * + * RFC5681 Section 3.1 specifies the default conservative values. + * RFC3390 specifies slightly more aggressive values. + * RFC6928 increases it to ten segments. + * Support for user specified value for initial flight size. + */ + if (V_tcp_initcwnd_segments) + return min(V_tcp_initcwnd_segments * maxseg, + max(2 * maxseg, V_tcp_initcwnd_segments * 1460)); + else if (V_tcp_do_rfc3390) + return min(4 * maxseg, max(2 * maxseg, 4380)); + else { + /* Per RFC5681 Section 3.1 */ + if (maxseg > 2190) + return (2 * maxseg); + else if (maxseg > 1095) + return (3 * maxseg); + else + return (4 * maxseg); + } } Modified: head/sys/netinet/tcp_stacks/rack.c ============================================================================== --- head/sys/netinet/tcp_stacks/rack.c Fri Jan 25 13:48:40 2019 (r343427) +++ head/sys/netinet/tcp_stacks/rack.c Fri Jan 25 13:57:09 2019 (r343428) @@ -1425,21 +1425,9 @@ rack_cc_after_idle(struct tcpcb *tp, int reduce_larges if (tp->snd_cwnd == 1) i_cwnd = tp->t_maxseg; /* SYN(-ACK) lost */ - else if (V_tcp_initcwnd_segments) - i_cwnd = min((V_tcp_initcwnd_segments * tp->t_maxseg), - max(2 * tp->t_maxseg, V_tcp_initcwnd_segments * 1460)); - else if (V_tcp_do_rfc3390) - i_cwnd = min(4 * tp->t_maxseg, - max(2 * tp->t_maxseg, 4380)); - else { - /* Per RFC5681 Section 3.1 */ - if (tp->t_maxseg > 2190) - i_cwnd = 2 * tp->t_maxseg; - else if (tp->t_maxseg > 1095) - i_cwnd = 3 * tp->t_maxseg; - else - i_cwnd = 4 * tp->t_maxseg; - } + else + i_cwnd = tcp_compute_initwnd(tcp_maxseg(tp)); + if (reduce_largest) { /* * Do we reduce the largest cwnd to make Modified: head/sys/netinet/tcp_var.h ============================================================================== --- head/sys/netinet/tcp_var.h Fri Jan 25 13:48:40 2019 (r343427) +++ head/sys/netinet/tcp_var.h Fri Jan 25 13:57:09 2019 (r343428) @@ -942,6 +942,7 @@ void tcp_sack_partialack(struct tcpcb *, struct tcphd void tcp_free_sackholes(struct tcpcb *tp); int tcp_newreno(struct tcpcb *, struct tcphdr *); int tcp_compute_pipe(struct tcpcb *); +uint32_t tcp_compute_initwnd(uint32_t); void tcp_sndbuf_autoscale(struct tcpcb *, struct socket *, uint32_t); struct mbuf * tcp_m_copym(struct mbuf *m, int32_t off0, int32_t *plen, _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
