From: David Ahern <dsa@cumulusnetworks.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
netdev@vger.kernel.org, shm@cumulusnetworks.com,
roopa@cumulusnetworks.com, gospo@cumulusnetworks.com,
jtoppins@cumulusnetworks.com, nikolay@cumulusnetworks.com,
ddutt@cumulusnetworks.com, nicolas.dichtel@6wind.com,
stephen@networkplumber.org, hadi@mojatatu.com,
davem@davemloft.net, svaidya@brocade.com, mingo@kernel.org,
luto@amacapital.net
Subject: Re: [PATCH net-next 14/16] net: Add sk_bind_dev_if to task_struct
Date: Tue, 28 Jul 2015 10:07:17 -0600 [thread overview]
Message-ID: <55B7A8B5.6020305@cumulusnetworks.com> (raw)
In-Reply-To: <1438099265.20182.63.camel@edumazet-glaptop2.roam.corp.google.com>
On 7/28/15 10:01 AM, Eric Dumazet wrote:
> On Tue, 2015-07-28 at 14:19 +0200, Hannes Frederic Sowa wrote:
>> Hello Eric,
>>
>> On Mon, 2015-07-27 at 15:33 -0500, Eric W. Biederman wrote:
>>> David Ahern <dsa@cumulusnetworks.com> writes:
>>>
>>>> Allow tasks to have a default device index for binding sockets. If
>>>> set
>>>> the value is passed to all AF_INET/AF_INET6 sockets when they are
>>>> created.
>>>>
>>>> The task setting is passed parent to child on fork, but can be set
>>>> or
>>>> changed after task creation using prctl (if task has CAP_NET_ADMIN
>>>> permissions). The setting for a socket can be retrieved using
>>>> prctl().
>>>> This option allows an administrator to restrict a task to only
>>>> send/receive
>>>> packets through the specified device. In the case of VRF devices
>>>> this
>>>> option restricts tasks to a specific VRF.
>>>>
>>>> Correlation of the device index to a specific VRF, ie.,
>>>> ifindex --> VRF device --> VRF id
>>>> is left to userspace.
>>>
>>> Nacked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>>>
>>> Because it is broken by design. Your routing device is only safe for
>>> programs that know it's limitations it is not appropriate for general
>>> applications.
>>>
>>> Since you don't even seen to know it's limitations I think this is a
>>> bad path to walk down.
>>
>> Can you please elaborate about the broken by design?
>>
>> Different operating systems are already using this approach with good
>> success. I read your other mail regarding isolation of different VRFs
>> and I agree that all code which persists state depending solely on the
>> IP address is affected by this and this must be dealt with and fixed
>> (actually, there aren't too many).
>>
>> But I wouldn't call that broken by design. This stuff will get fixed
>> like e.g. cross-talk between fragmentation queues, icmp rate limiters
>> etc, which could already happen in the past.
>>
>> What is your opinion on the fundamental approach only from a user
>> perspective? Do you think that is broken, too?
>
> I agree with Eric here.
>
> This sk_bind_dev_if on task_struct is quite a hack.
>
> What will be added next ? An array of dev_if ? netfilter support ?
> af_packet support ? What about /proc files and netlink dumps ?
It could just as easily be a pointer to a struct (e.g., struct net_ctx)
such that the intrusion to task_struct is simply 8 bytes -- very similar
to the nsproxy used for the assorted namespaces. The struct can then
contain whatever network config is imposed on the task.
>
> We already have network namespaces. Extend this if needed, instead of
> bypassing them.
Problems with using network namespaces for VRFs has been discussed in
the past. e.g.,
http://www.spinics.net/lists/netdev/msg298368.html
David
>
> No need to add something else (with lack of proper reporting for various
> tools)
>
>
next prev parent reply other threads:[~2015-07-28 16:07 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-27 18:30 [net-next 0/16] Proposal for VRF-lite - v3 David Ahern
2015-07-27 18:30 ` [PATCH net-next 01/16] net: Refactor rtable allocation and initialization David Ahern
2015-07-27 18:30 ` [PATCH net-next 02/16] net: export a few FIB functions David Ahern
2015-07-27 18:30 ` [PATCH net-next 03/16] net: Introduce VRF related flags and helpers David Ahern
2015-07-27 18:30 ` [PATCH net-next 04/16] net: Use VRF device index for lookups on RX David Ahern
2015-07-27 18:30 ` [PATCH net-next 05/16] net: Use VRF device index for lookups on TX David Ahern
2015-07-27 18:30 ` [PATCH net-next 06/16] net: Tx via VRF device David Ahern
2015-07-27 18:31 ` [PATCH net-next 07/16] net: Add inet_addr lookup by table David Ahern
2015-07-27 18:31 ` [PATCH net-next 08/16] net: Fix up inet_addr_type checks David Ahern
2015-07-27 18:31 ` [PATCH net-next 09/16] net: Add routes to the table associated with the device David Ahern
2015-07-27 18:31 ` [PATCH net-next 10/16] net: Use passed in table for nexthop lookups David Ahern
2015-07-27 18:31 ` [PATCH net-next 11/16] net: Use VRF device index for socket lookups David Ahern
2015-07-27 18:31 ` [PATCH net-next 12/16] net: Add ipv4 route helper to set next hop David Ahern
2015-07-27 18:31 ` [PATCH net-next 13/16] net: Introduce VRF device driver - v2 David Ahern
2015-07-27 20:01 ` Nikolay Aleksandrov
2015-07-28 16:22 ` David Ahern
2015-07-27 18:31 ` [PATCH net-next 14/16] net: Add sk_bind_dev_if to task_struct David Ahern
2015-07-27 20:33 ` Eric W. Biederman
2015-07-28 12:19 ` Hannes Frederic Sowa
2015-07-28 13:54 ` Eric W. Biederman
2015-07-28 14:20 ` Hannes Frederic Sowa
2015-07-28 16:01 ` Eric Dumazet
2015-07-28 16:07 ` David Ahern [this message]
2015-07-28 16:52 ` Eric Dumazet
2015-07-28 15:25 ` Andy Lutomirski
2015-07-28 16:11 ` David Ahern
2015-07-28 17:12 ` Tom Herbert
2015-07-27 18:31 ` [PATCH net-next 15/16] net: Add chvrf command David Ahern
2015-07-27 18:31 ` [PATCH] iproute2: Add support for VRF device David Ahern
2015-07-27 20:30 ` [net-next 0/16] Proposal for VRF-lite - v3 Eric W. Biederman
2015-07-28 16:02 ` David Ahern
2015-07-28 17:07 ` Eric W. Biederman
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