Date: Fri, 15 Dec 2023 12:25:16 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 275774] IPv4 Mapper address problem Message-ID: <bug-275774-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D275774 Bug ID: 275774 Summary: IPv4 Mapper address problem Product: Base System Version: 15.0-CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: manu@freebsd.org Attachment #247054 text/plain mime type: Created attachment 247054 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D247054&action= =3Dedit udptest Hi, We have a problem at work with IPv4-Mapped address. Attached is two test program, udptest and udptest_recv. The first one send a udp datagram to 127.0.0.1 and if a response is receive= d it will send another one to the given ip address given in the first args. So we have machine A and machine B. - Start udptest_recv on machine A - Start udptest_recv on machine B - tcpdump -i lo0 on machine A - Start udptest XXX.XXX.XXX.XXX (ipv4 of machine B) on machine A What is expected : - machine A send 'abcd' to 127.0.0.1 - machine A receive 'abcd' - machine A sends back 'abcd' to machine A - machine A send 'efgh' to machine B - machine B receive 'efgh' from machine A What is happening : - machine A send 'abcd' to 127.0.0.1 - machine A receive 'abcd' - machine A sends back 'abcd' to machine A - machine A send 'efgh' to machine A - machine A receive 'efgh' from machine A - machine B receives nothing tcpdump -i lo0 on machine A gives us : tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on lo0, link-type NULL (BSD loopback), snapshot length 262144 byt= es 13:17:46.418063 IP 127.0.0.1.34254 > 127.0.0.1.1234: UDP, length 4 13:17:46.418233 IP 127.0.0.1.1234 > 127.0.0.1.34254: UDP, length 4 13:17:46.418341 IP 192.168.1.51.34254 > 192.168.1.50.1234: UDP, length 4 192.168.1.51 is the IPv4 of machine A and 192.168.1.50 the one of machine B So the second udp packet is send via lo0 Attached is also a patch that fixes it but we're not sure if that's the best way or not as we don't have much knowledge of our IP stack. On 13.2 the correct behavior is happening. On 15-CURRENT (3494f7c019fc6558a99f63 from December 8 2023) it doesn't work. Not tested on 14.0 (yet). --=20 You are receiving this mail because: You are the assignee for the bug.=
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