From: Jan Engelhardt <jengelh@inai.de>
To: Florian Westphal <fw@strlen.de>
Cc: Cole Dishington <Cole.Dishington@alliedtelesis.co.nz>,
pablo@netfilter.org, kadlec@netfilter.org, davem@davemloft.net,
kuba@kernel.org, linux-kernel@vger.kernel.org,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org
Subject: Re: [PATCH] netfilter: nf_conntrack: Add conntrack helper for ESP/IPsec
Date: Wed, 5 May 2021 14:16:57 +0200 (CEST) [thread overview]
Message-ID: <pq161666-47s-p680-552o-58poo05onr86@vanv.qr> (raw)
In-Reply-To: <20210414154021.GE14932@breakpoint.cc>
On Wednesday 2021-04-14 17:40, Florian Westphal wrote:
>
>Preface: AFAIU this tracker aims to 'soft-splice' two independent ESP
>connections, i.e.: saddr:spi1 -> daddr, daddr:spi2 <- saddr. [...] This can't
>be done as-is, because we don't know spi2 at the time the first ESP packet is
>received. The solution implemented here is introduction of a 'virtual esp id',
>computed when first ESP packet is received,[...]
I can't imagine this working reliably.
1. The IKE daemons could do an exchange whereby just one ESP flow is set up (from
daddr to saddr). It's unusual to do a one-way tunnel, but it's a possibility.
Then you only ever have ESP packets going from daddr to saddr.
2. Even if the IKE daemons set up what we would consider a normal tunnel,
i.e. one ESP flow per direction, there is no obligation that saddr has to
send anything. daddr could be contacting saddr solely with a protocol
that is both connectionless at L4 and which does not demand any L7 responses
either. Like ... syslog-over-udp?
3. Even under best conditions, what if two clients on the saddr network
simultaneously initiate a connection to daddr, how will you decide
which of the daddr ESP SPIs belongs to which saddr?
next prev parent reply other threads:[~2021-05-05 12:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 3:53 [PATCH] netfilter: nf_conntrack: Add conntrack helper for ESP/IPsec Cole Dishington
2021-04-14 15:40 ` Florian Westphal
2021-04-20 22:35 ` Cole Dishington
2021-04-26 11:54 ` Florian Westphal
2021-04-26 12:37 ` Florian Westphal
2021-05-03 1:06 ` [PATCH v3] " Cole Dishington
2021-05-04 19:22 ` Florian Westphal
2021-05-05 11:10 ` Florian Westphal
2021-05-05 12:16 ` Jan Engelhardt [this message]
2021-05-06 2:59 ` [PATCH] " Cole Dishington
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=pq161666-47s-p680-552o-58poo05onr86@vanv.qr \
--to=jengelh@inai.de \
--cc=Cole.Dishington@alliedtelesis.co.nz \
--cc=coreteam@netfilter.org \
--cc=davem@davemloft.net \
--cc=fw@strlen.de \
--cc=kadlec@netfilter.org \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=pablo@netfilter.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).