From: David Ahern <dsa@cumulusnetworks•com>
To: "Eric W. Biederman" <ebiederm@xmission•com>
Cc: Sowmini Varadhan <sowmini05@gmail•com>,
netdev <netdev@vger•kernel.org>,
Shrijeet Mukherjee <shm@cumulusnetworks•com>,
Roopa Prabhu <roopa@cumulusnetworks•com>,
Andy Gospodarek <gospo@cumulusnetworks•com>,
jtoppins@cumulusnetworks•com, nikolay@cumulusnetworks•com,
ddutt@cumulusnetworks•com,
Hannes Frederic Sowa <hannes@stressinduktion•org>,
Nicolas Dichtel <nicolas.dichtel@6wind•com>,
Stephen Hemminger <stephen@networkplumber•org>,
hadi@mojatatu•com, David Miller <davem@davemloft•net>
Subject: Re: [RFC net-next 3/6] net: Introduce VRF device driver - v2
Date: Thu, 09 Jul 2015 22:20:36 -0600 [thread overview]
Message-ID: <559F4814.70306@cumulusnetworks.com> (raw)
In-Reply-To: <87vbds64z4.fsf@x220.int.ebiederm.org>
On 7/9/15 9:55 PM, Eric W. Biederman wrote:
>> IP addresses are per interface and interfaces are uniquely assigned to
>> a VRF so why do you think IP addresses are not per VRF?
>
> I have read large swaths of the linux networking code over the years.
>
> Further I was thinking more about non-local addresses ip addresses, but
> I would not be surprised if there are also issues with local addresses.
Well, if someone has a specific example I'll take a look.
>
>>> Which means things like packet fragmentation reassembly
>>> can easily do the wrong thing. Similarly things like the xfrm for ipsec
>>> tunnels are not hooked into this mix.
>>>
>>> So I really do not see how this VRF/MRF thing as designed can support
>>> general purpose sockets. I am not certain it can correctly support any
>>> kind of socket except perhaps SOCK_RAW.
>>
>> Sockets bound to the VRF device work properly. Why do you think they won't?
>
> Because there are many locations in the network stack (like fragment
> reassembly) that make the assumption that ip addresses are unique and
> do not bother looking at network device or anything else. If fragments
> manage to come into play I don't expect it would be hard to poision a
> connections with fragments from another routing domain with overlapping
> ip addresses.
If that is true it is a problem with the networking stack today and is
completely independent of this VRF proposal.
> I guess if we are talking about SO_BINDTODEVICE which requires
> CAP_NET_RAW we aren't really talking ordinary applications so there is
> already a big helping of buyer beware.
>
> Still a blanket statement that sockets just work and there is nothing
> to be concerned about is just wrong.
If you have examples of something that does not work I will be happy to
look into it. As it stands I have a growing suite of test cases where my
comment is true.
David
next prev parent reply other threads:[~2015-07-10 4:20 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-06 15:03 [RFC net-next 0/6] Proposal for VRF-lite - v2 David Ahern
2015-07-06 15:03 ` [RFC net-next 1/6] fib: export symbols David Ahern
2015-07-06 15:03 ` [RFC net-next 2/6] net: Preparation for vrf device David Ahern
2015-07-08 8:37 ` Nicolas Dichtel
2015-07-08 8:40 ` Nicolas Dichtel
2015-07-08 16:10 ` David Ahern
2015-07-06 15:03 ` [RFC net-next 3/6] net: Introduce VRF device driver - v2 David Ahern
2015-07-06 15:42 ` Nicolas Dichtel
2015-07-06 16:37 ` Nikolay Aleksandrov
2015-07-06 16:46 ` David Ahern
2015-07-08 9:27 ` Nicolas Dichtel
2015-07-08 16:38 ` David Ahern
2015-07-08 18:34 ` Sowmini Varadhan
2015-07-09 17:19 ` David Ahern
2015-07-09 17:28 ` Sowmini Varadhan
2015-07-10 1:36 ` Eric W. Biederman
2015-07-10 2:12 ` David Ahern
2015-07-10 3:55 ` Eric W. Biederman
2015-07-10 4:20 ` David Ahern [this message]
2015-07-10 4:56 ` Eric W. Biederman
2015-07-10 18:42 ` David Ahern
2015-07-10 2:39 ` David Ahern
2015-07-10 3:28 ` Sowmini Varadhan
2015-07-10 3:44 ` David Ahern
2015-07-06 15:03 ` [RFC net-next 4/6] net: Modifications to ipv4 stack for VRF devices David Ahern
2015-07-06 15:03 ` [RFC net-next 5/6] net: Add sk_bind_dev_if to task_struct David Ahern
2015-07-06 15:03 ` [RFC net-next 6/6] net: Add chvrf command David Ahern
2015-07-06 15:03 ` [RFC PATCH] iproute2: Add support for VRF device David Ahern
2015-07-06 15:40 ` [RFC net-next 0/6] Proposal for VRF-lite - v2 Nicolas Dichtel
2015-07-06 17:53 ` Shrijeet Mukherjee
2015-07-08 9:30 ` Nicolas Dichtel
2015-07-10 5:14 ` Scott Feldman
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