Date: Sat, 20 Feb 2021 12:40:12 +0100 From: Michael Tuexen <Michael.Tuexen@lurchi.franken.de> To: Doug Hardie <bc979@lafn.org> Cc: "net@freebsd.org" <net@FreeBSD.org> Subject: Re: IPv6 Fragmentation Message-ID: <D8F27F01-3D6A-4F5F-A7C2-3342842BDE24@lurchi.franken.de> In-Reply-To: <A01F640F-E412-474C-A34C-19B7219BD84D@sermon-archive.info> References: <CB0FB5AB-5A37-4C40-A103-3E0D97CEA6B9@sermon-archive.info> <472A2B49-9BEC-4335-B6FB-AC4DAA0F0310@lurchi.franken.de> <A01F640F-E412-474C-A34C-19B7219BD84D@sermon-archive.info>
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> On 20. Feb 2021, at 05:32, Doug Hardie <bc979@lafn.org> wrote: >=20 >> On 19 February 2021, at 01:48, Michael Tuexen = <michael.tuexen@lurchi.franken.de> wrote: >>=20 >>> On 19. Feb 2021, at 03:29, Doug Hardie <bc979@lafn.org> wrote: >>>=20 >>> I don't know if this is a feature or a bug. On FreeBSD 9, the = following ping worked: >>>=20 >>> ping6 -s 5000 -b 6000 fe80::213:72ff:fec3:180f%dc0 >> I don't have a dc0 interface, but using re0 at one side and bge at = the other, I get >> with FreeBSD CURRENT: >> tuexen@cirrus:~ % ping6 -s 5000 -b 6000 fe80::2e09:4dff:fe00:c00%re0 >> PING6(5048=3D40+8+5000 bytes) fe80::aaa1:59ff:fe0c:da92%re0 --> = fe80::2e09:4dff:fe00:c00%re0 >> 5008 bytes from fe80::2e09:4dff:fe00:c00%re0, icmp_seq=3D0 hlim=3D255 = time=3D0.393 ms >> 5008 bytes from fe80::2e09:4dff:fe00:c00%re0, icmp_seq=3D1 hlim=3D255 = time=3D0.419 ms >> 5008 bytes from fe80::2e09:4dff:fe00:c00%re0, icmp_seq=3D2 hlim=3D255 = time=3D0.354 ms >> 5008 bytes from fe80::2e09:4dff:fe00:c00%re0, icmp_seq=3D3 hlim=3D255 = time=3D0.446 ms >> 5008 bytes from fe80::2e09:4dff:fe00:c00%re0, icmp_seq=3D4 hlim=3D255 = time=3D0.421 ms >> 5008 bytes from fe80::2e09:4dff:fe00:c00%re0, icmp_seq=3D5 hlim=3D255 = time=3D0.372 ms >> ^C >> --- fe80::2e09:4dff:fe00:c00%re0 ping6 statistics --- >> 6 packets transmitted, 6 packets received, 0.0% packet loss >> round-trip min/avg/max/std-dev =3D 0.354/0.401/0.446/0.031 ms >>=20 >> Best regards >> Michael >>>=20 >>> It had to be stopped, but it returned the number of ping responses = received along with statistics. >>>=20 >>> With FreeBSD 12.2 and 13.0-BETA2, it returns 100% packet loss. = tcpdump shows that it properly fragments the data, sends it, the other = end receives it and sends back the ACKs. The ACKs are received, but = somehow ping doesn't find out that the packets were received. >>>=20 >>> Without the -s and -b arguments, it works and you get 100% packets = received. >=20 > I found the problem. pf does not handle IPv6 packets that are = fragmented the obvious way. I suspect it is because icmp header is only = in the first fragment. I had to reassemble fragments in pf in order to = make the large pings work. Glad you found the problem. Thanks for letting us know. Best regards Michael >=20 > -- Doug >=20 > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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