From aad7fca9c504effdaf3c77dd635e85c94dc4521d Mon Sep 17 00:00:00 2001 From: Jordan Whited Date: Fri, 24 Mar 2023 15:09:47 -0700 Subject: tun: disqualify tcp4 packets w/IP options from coalescing IP options were not being compared prior to coalescing. They are not commonly used. Disqualification due to nonzero options is in line with the kernel. Reviewed-by: Denton Gentry Signed-off-by: Jordan Whited Signed-off-by: Jason A. Donenfeld --- tun/tcp_offload_linux.go | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'tun/tcp_offload_linux.go') diff --git a/tun/tcp_offload_linux.go b/tun/tcp_offload_linux.go index e807f00..4912efd 100644 --- a/tun/tcp_offload_linux.go +++ b/tun/tcp_offload_linux.go @@ -397,9 +397,6 @@ func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool) if totalLen != len(pkt) { return false } - if iphLen < 20 || iphLen > 60 { - return false - } } if len(pkt) < iphLen { return false @@ -474,13 +471,16 @@ func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool) return false } -func isTCP4(b []byte) bool { +func isTCP4NoIPOptions(b []byte) bool { if len(b) < 40 { return false } if b[0]>>4 != 4 { return false } + if b[0]&0x0F != 5 { + return false + } if b[9] != unix.IPPROTO_TCP { return false } @@ -511,7 +511,7 @@ func handleGRO(bufs [][]byte, offset int, tcp4Table, tcp6Table *tcpGROTable, toW } var coalesced bool switch { - case isTCP4(bufs[i][offset:]): + case isTCP4NoIPOptions(bufs[i][offset:]): // ipv4 packets w/IP options do not coalesce coalesced = tcpGRO(bufs, offset, i, tcp4Table, false) case isTCP6NoEH(bufs[i][offset:]): // ipv6 packets w/extension headers do not coalesce coalesced = tcpGRO(bufs, offset, i, tcp6Table, true) -- cgit v1.2.3-59-g8ed1b