diff options
| author | hiren <hiren@FreeBSD.org> | 2016-12-05 06:20:27 +0000 |
|---|---|---|
| committer | hiren <hiren@FreeBSD.org> | 2016-12-05 06:20:27 +0000 |
| commit | 356fbc072920d7e71c42b310d6bfa2d1a3d36f9f (patch) | |
| tree | d2dda34dda38eeb32504f49d10679f4fec2e601c /sys/netinet/tcp_syncache.c | |
| parent | ccf958c4684e753bca88fbe5b9eedbaf803fb5ec (diff) | |
| download | FreeBSD-src-356fbc072920d7e71c42b310d6bfa2d1a3d36f9f.zip FreeBSD-src-356fbc072920d7e71c42b310d6bfa2d1a3d36f9f.tar.gz | |
MFC r308943
For RTT calculations mid-session, we explicitly ignore ACKs with tsecr of 0 as
many borken middle-boxes tend to do that. But during 3whs, in syncache_expand(),
we don't do that which causes us to send a RST to such a client. Relax this
constraint by only using tsecr to compare against timestamp that we sent when it
is not 0. As a result, we'd now accept the final ACK of 3whs with tsecr of 0.
Sponsored by: Limelight Networks
Diffstat (limited to 'sys/netinet/tcp_syncache.c')
| -rw-r--r-- | sys/netinet/tcp_syncache.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c index 74a84c7..ee9bf95 100644 --- a/sys/netinet/tcp_syncache.c +++ b/sys/netinet/tcp_syncache.c @@ -1069,10 +1069,17 @@ syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, } /* - * If timestamps were negotiated the reflected timestamp - * must be equal to what we actually sent in the SYN|ACK. + * If timestamps were negotiated, the reflected timestamp + * must be equal to what we actually sent in the SYN|ACK + * except in the case of 0. Some boxes are known for sending + * broken timestamp replies during the 3whs (and potentially + * during the connection also). + * + * Accept the final ACK of 3whs with reflected timestamp of 0 + * instead of sending a RST and deleting the syncache entry. */ - if ((to->to_flags & TOF_TS) && to->to_tsecr != sc->sc_ts) { + if ((to->to_flags & TOF_TS) && to->to_tsecr && + to->to_tsecr != sc->sc_ts) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: TSECR %u != TS %u, " "segment rejected\n", |
