svn commit: r357116 - in head/sys/netinet: . cc tcp_stacks

[Michael Tuexen]

Author: tuexen
Date: Sat Jan 25 13:45:10 2020
New Revision: 357116
URL: https://svnweb.freebsd.org/changeset/base/357116

Log:
  Sending CWR after an RTO is according to RFC 3168 generally required
  and not only for the DCTCP congestion control.
  
  Submitted by:		Richard Scheffenegger
  Reviewed by:		rgrimes, tuexen@, Cheng Cui
  MFC after:		1 week
  Differential Revision:	https://reviews.freebsd.org/D23119

Modified:
  head/sys/netinet/cc/cc_dctcp.c
  head/sys/netinet/tcp_input.c
  head/sys/netinet/tcp_stacks/rack.c

Modified: head/sys/netinet/cc/cc_dctcp.c
==============================================================================
--- head/sys/netinet/cc/cc_dctcp.c	Sat Jan 25 13:34:29 2020	(r357115)
+++ head/sys/netinet/cc/cc_dctcp.c	Sat Jan 25 13:45:10 2020	(r357116)
@@ -284,7 +284,6 @@ dctcp_cong_signal(struct cc_var *ccv, uint32_t type)
 			dctcp_data->ece_curr = 1;
 			break;
 		case CC_RTO:
-			CCV(ccv, t_flags2) |= TF2_ECN_SND_CWR;
 			dctcp_update_alpha(ccv);
 			dctcp_data->save_sndnxt += CCV(ccv, t_maxseg);
 			dctcp_data->num_cong_events++;

Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c	Sat Jan 25 13:34:29 2020	(r357115)
+++ head/sys/netinet/tcp_input.c	Sat Jan 25 13:45:10 2020	(r357116)
@@ -460,6 +460,8 @@ cc_cong_signal(struct tcpcb *tp, struct tcphdr *th, ui
 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, tp->snd_cwnd) / 2 /
 		    maxseg) * maxseg;
 		tp->snd_cwnd = maxseg;
+		if (tp->t_flags2 & TF2_ECN_PERMIT)
+			tp->t_flags2 |= TF2_ECN_SND_CWR;
 		break;
 	case CC_RTO_ERR:
 		TCPSTAT_INC(tcps_sndrexmitbad);

Modified: head/sys/netinet/tcp_stacks/rack.c
==============================================================================
--- head/sys/netinet/tcp_stacks/rack.c	Sat Jan 25 13:34:29 2020	(r357115)
+++ head/sys/netinet/tcp_stacks/rack.c	Sat Jan 25 13:45:10 2020	(r357116)
@@ -1813,6 +1813,8 @@ rack_cong_signal(struct tcpcb *tp, struct tcphdr *th, 
 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, tp->snd_cwnd) / 2 /
 		    ctf_fixed_maxseg(tp)) * ctf_fixed_maxseg(tp);
 		tp->snd_cwnd = ctf_fixed_maxseg(tp);
+		if (tp->t_flags2 & TF2_ECN_PERMIT)
+			tp->t_flags2 |= TF2_ECN_SND_CWR;
 		break;
 	case CC_RTO_ERR:
 		TCPSTAT_INC(tcps_sndrexmitbad);