Date: Tue, 05 Jul 2016 22:54:39 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 210860] [pf] [ip6] Incorrect TCP checksums after rdr Message-ID: <bug-210860-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D210860 Bug ID: 210860 Summary: [pf] [ip6] Incorrect TCP checksums after rdr Product: Base System Version: 10.3-STABLE Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: vieira+fbsd@yubo.be PF seems to incorrectly computes the checksum of IPv6 TCP packets that it rewrites as part of a simple rdr rule. E.g., with the following rules: table <forward_subnets> {2001:16d8:ee03::cafe:d00d/128,!::1} rdr pass log on lo0 inet6 proto tcp to <forward_subnets> -> ::1 port 12300 pass out log route-to lo0 inet6 proto tcp to <forward_subnets> keep state and while running nc -l ::1 12300 trying nc -vz 2001:16d8:ee03::cafe:d00d 8= 0 to see if any packets get to nc listening on 12300 shows that nothing is recei= ved although tcpdump -n -e -ttt -i pflog0 -vvv shows the following incorrect checksum in rdr: 00:00:00.000000 rule 0..16777216/0(match): pass out on vtnet0: (flowlabel 0x481b8, hlim 64, next-header TCP (6) payload length: 40) 2a03:b0c0:1:d0::425:1001.29559 > 2001:16d8:ee03::cafe:d00d.80: Flags [S], c= ksum 0xafd2 (incorrect -> 0x7083), seq 417394668, win 65535, options [mss 1440,nop,wscale 6,sackOK,TS val 240470 ecr 0], length 0 00:00:00.000049 rule 0..16777216/0(match): rdr in on lo0: (flowlabel 0x481b= 8, hlim 64, next-header TCP (6) payload length: 40) 2a03:b0c0:1:d0::425:1001.2= 9559 > ::1.12300: Flags [S], cksum 0x3fff (incorrect -> 0x00b0), seq 417394668, = win 65535, options [mss 1440,nop,wscale 6,sackOK,TS val 240470 ecr 0], length 0 tcpdump'ing lo0 repeatedly shows "cksum 0xafd2 (incorrect -> 0x...)": 22:51:58.407819 IP6 (flowlabel 0x4766f, hlim 64, next-header TCP (6) payload length: 40) fbsd.yubo.be.10904 > 2001:16d8:ee03::cafe:d00d.http: Flags [S], cksum 0xafd2 (incorrect -> 0x12d1), seq 1237643503, win 65535, options [mss 1440,nop,wscale 6,sackOK,TS val 401406 ecr 0], length 0 22:52:01.438778 IP6 (flowlabel 0x4766f, hlim 64, next-header TCP (6) payload length: 40) fbsd.yubo.be.10904 > 2001:16d8:ee03::cafe:d00d.http: Flags [S], cksum 0xafd2 (incorrect -> 0x06fb), seq 1237643503, win 65535, options [mss 1440,nop,wscale 6,sackOK,TS val 404436 ecr 0], length 0 Note that the inet version of the same rules do work as expected, e.g. table <forward_subnets> {188.113.88.193/32,!127.0.0.1/8} rdr pass on lo0 inet proto tcp to <forward_subnets> -> 127.0.0.1 port 12300 pass out route-to lo0 inet proto tcp to <forward_subnets> keep state --=20 You are receiving this mail because: You are the assignee for the bug.=
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