[Devel] Re: [PATCH 5/5] net: Make AF_UNIX per network namespace safe.

[Eric W. Biederman]

Patrick McHardy <kaber at trash.net> writes:

> Eric W. Biederman wrote:
>> Because of the global nature of garbage collection, and because of the
>> cost of per namespace hash tables unix_socket_table has been kept
>> global.  With a filter added on lookups so we don't see sockets from
>> the wrong namespace.
>> 
>> Currently I don't fold the namesapce into the hash so multiple
>> namespaces using the same socket name will be guaranteed a hash
>> collision.
>
>
> That doesn't sound like a good thing :) Is there a reason for
> not avoiding the collisions?

Two reasons.  Minimizing the size of the changes to make review
easier, and I don't know if hash collisions are likely in practice
or if they matter.  I don't believe we can't physically collide and
have the same inode because we make a node in the filesystem.  The
abstract domain is local to linux and so people don't use it as much.

All of which boils down to.  I don't see it matter a heck of a lot
especially initially.  So I did the traditional unix thing and started
with a simple and stupid implementation.  But it didn't quite feel
right to me either so I documented it.

Whipping up a patch to take the namespace into account in mkname
doesn't look to hard though.

Eric
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