svn commit: r365586 - in stable/12/sys/netinet: . cc tcp_stacks

[Michael Tuexen]

Author: tuexen
Date: Thu Sep 10 16:44:28 2020
New Revision: 365586
URL: https://svnweb.freebsd.org/changeset/base/365586

Log:
  MFC r357116:
  
  Sending CWR after an RTO is according to RFC 3168 generally required
  and not only for the DCTCP congestion control.

Modified:
  stable/12/sys/netinet/cc/cc_dctcp.c
  stable/12/sys/netinet/tcp_input.c
  stable/12/sys/netinet/tcp_stacks/rack.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/netinet/cc/cc_dctcp.c
==============================================================================
--- stable/12/sys/netinet/cc/cc_dctcp.c	Thu Sep 10 15:58:37 2020	(r365585)
+++ stable/12/sys/netinet/cc/cc_dctcp.c	Thu Sep 10 16:44:28 2020	(r365586)
@@ -282,7 +282,6 @@ dctcp_cong_signal(struct cc_var *ccv, uint32_t type)
 			dctcp_data->ece_curr = 1;
 			break;
 		case CC_RTO:
-			CCV(ccv, t_flags) |= TF_ECN_SND_CWR;
 			dctcp_update_alpha(ccv);
 			dctcp_data->save_sndnxt += CCV(ccv, t_maxseg);
 			dctcp_data->num_cong_events++;

Modified: stable/12/sys/netinet/tcp_input.c
==============================================================================
--- stable/12/sys/netinet/tcp_input.c	Thu Sep 10 15:58:37 2020	(r365585)
+++ stable/12/sys/netinet/tcp_input.c	Thu Sep 10 16:44:28 2020	(r365586)
@@ -438,6 +438,8 @@ 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_flags & TF_ECN_PERMIT)
+			tp->t_flags |= TF_ECN_SND_CWR;
 		break;
 	case CC_RTO_ERR:
 		TCPSTAT_INC(tcps_sndrexmitbad);

Modified: stable/12/sys/netinet/tcp_stacks/rack.c
==============================================================================
--- stable/12/sys/netinet/tcp_stacks/rack.c	Thu Sep 10 15:58:37 2020	(r365585)
+++ stable/12/sys/netinet/tcp_stacks/rack.c	Thu Sep 10 16:44:28 2020	(r365586)
@@ -1444,6 +1444,8 @@ rack_cong_signal(struct tcpcb *tp, struct tcphdr *th, 
 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, tp->snd_cwnd) / 2 /
 		    tp->t_maxseg) * tp->t_maxseg;
 		tp->snd_cwnd = tp->t_maxseg;
+		if (tp->t_flags & TF_ECN_PERMIT)
+			tp->t_flags |= TF_ECN_SND_CWR;
 		break;
 	case CC_RTO_ERR:
 		TCPSTAT_INC(tcps_sndrexmitbad);