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Date:      Tue, 23 Jan 2024 19:42:10 +0100
From:      Kristof Provost <kp@FreeBSD.org>
To:        "Herbert J. Skuhra" <herbert@gojira.at>
Cc:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject:   Re: git: 54c62e3e5d8c - main - pf: work around icmp6 packet-too-big not being sent when binat-ing
Message-ID:  <1E1C3472-0AF3-457B-A27A-89679770EA62@FreeBSD.org>
In-Reply-To: <87v87jkii9.wl-herbert@gojira.at>
References:  <202401221252.40MCqpf6047526@gitrepo.freebsd.org> <87v87jkii9.wl-herbert@gojira.at>

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On 23 Jan 2024, at 19:32, Herbert J. Skuhra wrote:
> On Mon, 22 Jan 2024 13:52:51 +0100, Kristof Provost wrote:
>>
>> The branch main has been updated by kp:
>>
>> URL: https://cgit.FreeBSD.org/src/commit/?id=3D54c62e3e5d8cd90c5571a1d=
4c8c5f062d580480e
>>
>> commit 54c62e3e5d8cd90c5571a1d4c8c5f062d580480e
>> Author:     Kristof Provost <kp@FreeBSD.org>
>> AuthorDate: 2024-01-17 17:11:27 +0000
>> Commit:     Kristof Provost <kp@FreeBSD.org>
>> CommitDate: 2024-01-22 11:52:14 +0000
>>
>>     pf: work around icmp6 packet-too-big not being sent when binat-ing=

>>
>>     If we're applying NPTv6 we pass a packet with a modified source an=
d/or
>>     destination address to the network stack.
>>
>>     If that packet then turns out to be larger than the MTU of the sen=
ding
>>     interface the stack will attempt to generate an icmp6 packet-too-b=
ig
>>     error, but may fail to look up the appropriate source address for =
that
>>     error message. Even if it does, pf would still have to undo the bi=
nat
>>     operation inside the icmp6 packet so the sending host can make sen=
se of
>>     the error.
>>
>>     We can avoid both problems entirely by having pf also perform the =
MTU
>>     check (taking the potential refragmentation into account), and
>>     generating the icmp6 error directly in pf.
>>
>>     See also:       https://redmine.pfsense.org/issues/14290
>>     Sponsored by:   Rubicon Communications, LLC ("Netgate")
>>     Differential Revision:  https://reviews.freebsd.org/D43499
>> ---
>>  sys/net/pfvar.h          |  1 +
>>  sys/netpfil/pf/pf.c      | 12 ++++++++++++
>>  sys/netpfil/pf/pf_norm.c | 15 +++++++++++++++
>>  3 files changed, 28 insertions(+)
>
> Does this change cause problems for others too?
>
> - ssh over IPv6 permanently disconnecting
> (client_loop: send disconnect: Broken pipe)
> - ssh connections over IPv6 hanging
> - git pull not working
> Fssh_ssh_dispatch_run_fatal: Connection to 2604:1380:4091:a001::24ca:1 =
port 22: Permission denied
> fatal: Could not read from remote repository.
>
Can you include your pf.conf and a packet capture demonstrating one of th=
ese issues?

Best regards,
Kristof



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