Module Name: src Committed By: kardel Date: Wed Sep 2 15:08:46 UTC 2020
Modified Files: src/sys/netinet: tcp_input.c Log Message: Fix fast path for uni directional transfers pure ACK case: drag snd_wl2 along so only newer ACKs can update the window size. also avoids the state where snd_wl2 is eventually larger than th_ack and thus blocking the window update mechanism and the connection gets stuck for a loooong time in the zero sized send window state. see PR/kern 55567 ok thorpej@, also found in FreeBSD To generate a diff of this commit: cvs rdiff -u -r1.418 -r1.419 src/sys/netinet/tcp_input.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/netinet/tcp_input.c diff -u src/sys/netinet/tcp_input.c:1.418 src/sys/netinet/tcp_input.c:1.419 --- src/sys/netinet/tcp_input.c:1.418 Mon Jul 6 18:49:12 2020 +++ src/sys/netinet/tcp_input.c Wed Sep 2 15:08:46 2020 @@ -1,4 +1,4 @@ -/* $NetBSD: tcp_input.c,v 1.418 2020/07/06 18:49:12 christos Exp $ */ +/* $NetBSD: tcp_input.c,v 1.419 2020/09/02 15:08:46 kardel Exp $ */ /* * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. @@ -148,7 +148,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.418 2020/07/06 18:49:12 christos Exp $"); +__KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.419 2020/09/02 15:08:46 kardel Exp $"); #ifdef _KERNEL_OPT #include "opt_inet.h" @@ -1897,6 +1897,19 @@ after_listen: tp->snd_fack = tp->snd_una; if (SEQ_LT(tp->snd_high, tp->snd_una)) tp->snd_high = tp->snd_una; + /* + * drag snd_wl2 along so only newer + * ACKs can update the window size. + * also avoids the state where snd_wl2 + * is eventually larger than th_ack and thus + * blocking the window update mechanism and + * the connection gets stuck for a loooong + * time in the zero sized send window state. + * + * see PR/kern 55567 + */ + tp->snd_wl2 = tp->snd_una; + m_freem(m); /*