diff options
| author | Michael Tuexen <tuexen@FreeBSD.org> | 2020-08-08 19:39:38 +0000 |
|---|---|---|
| committer | Michael Tuexen <tuexen@FreeBSD.org> | 2020-08-08 19:39:38 +0000 |
| commit | 1bea15e601ad4fae5c2912758715fcaa08aa2404 (patch) | |
| tree | a209bc9faea9edea052f11a120e111b03f34a2b7 /sys/netinet | |
| parent | d7c8186d675306c61b2f42376ad0dcc6813312aa (diff) | |
Improve the ECN negotiation when the TCP SYN-cache is used by making
sure that
* ECN is disabled if the client sends an non-ECN-setup SYN segment.
* ECN is disabled is the ECN-setup SYN-ACK segment is retransmitted more
than net.inet.tcp.ecn.maxretries times.
Reviewed by: rscheff
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D26008
Notes
svn path=/head/; revision=364054
Diffstat (limited to 'sys/netinet')
| -rw-r--r-- | sys/netinet/tcp_syncache.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c index 7a46acf3a878..e564540b007d 100644 --- a/sys/netinet/tcp_syncache.c +++ b/sys/netinet/tcp_syncache.c @@ -510,6 +510,9 @@ syncache_timer(void *xsch) sch->sch_nextc = sc->sc_rxttime; continue; } + if (sc->sc_rxmits > V_tcp_ecn_maxretries) { + sc->sc_flags &= ~SCF_ECN; + } if (sc->sc_rxmits > V_tcp_syncache.rexmt_limit) { if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Retransmits exhausted, " @@ -1505,6 +1508,13 @@ syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, sc->sc_tsreflect = to->to_tsval; else sc->sc_flags &= ~SCF_TIMESTAMP; + /* + * Disable ECN if needed. + */ + if ((sc->sc_flags & SCF_ECN) && + ((th->th_flags & (TH_ECE|TH_CWR)) != (TH_ECE|TH_CWR))) { + sc->sc_flags &= ~SCF_ECN; + } #ifdef MAC /* * Since we have already unconditionally allocated label |