diff options
| author | dillon <dillon@FreeBSD.org> | 2002-12-14 07:31:51 +0000 |
|---|---|---|
| committer | dillon <dillon@FreeBSD.org> | 2002-12-14 07:31:51 +0000 |
| commit | c366943770e3324b93b9c11b53a443b2a1ecf9a4 (patch) | |
| tree | ddc8f86d248a104e77a46a79abe54a831af4f445 /sys | |
| parent | 766e48456088359c365ab659a0a92186ab8e4801 (diff) | |
| download | FreeBSD-src-c366943770e3324b93b9c11b53a443b2a1ecf9a4.zip FreeBSD-src-c366943770e3324b93b9c11b53a443b2a1ecf9a4.tar.gz | |
Bruce forwarded this tidbit from an analysis Van Jacobson did on an
apparent ack-on-ack problem with FreeBSD. Prof. Jacobson noticed a
case in our TCP stack which would acknowledge a received ack-only packet,
which is not legal in TCP.
Submitted by: Van Jacobson <van@packetdesign.com>,
bmah@packetdesign.com (Bruce A. Mah)
MFC after: 7 days
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/netinet/tcp_input.c | 7 | ||||
| -rw-r--r-- | sys/netinet/tcp_reass.c | 7 |
2 files changed, 12 insertions, 2 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 110a870..31f9b05 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -1463,7 +1463,12 @@ trimthenstep6: tcpstat.tcps_rcvduppack++; tcpstat.tcps_rcvdupbyte += tlen; tcpstat.tcps_pawsdrop++; - goto dropafterack; + if (tlen) { + goto dropafterack; + } else { + printf("PAWS ack-on-ack loop avoided\n"); + goto drop; + } } } diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c index 110a870..31f9b05 100644 --- a/sys/netinet/tcp_reass.c +++ b/sys/netinet/tcp_reass.c @@ -1463,7 +1463,12 @@ trimthenstep6: tcpstat.tcps_rcvduppack++; tcpstat.tcps_rcvdupbyte += tlen; tcpstat.tcps_pawsdrop++; - goto dropafterack; + if (tlen) { + goto dropafterack; + } else { + printf("PAWS ack-on-ack loop avoided\n"); + goto drop; + } } } |
