Re: RFC: support srcaddr= option to bind to local IPs.

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Tue, 2010-09-07 at 14:10 -0700, Ben Greear wrote:
> On 09/07/2010 01:54 PM, Trond Myklebust wrote:
> > On Tue, 2010-09-07 at 13:41 -0700, Ben Greear wrote:
> >> On 09/07/2010 10:56 AM, Trond Myklebust wrote:
> >>> On Fri, 2010-09-03 at 11:55 -0700, Ben Greear wrote:
> >>>> This patch lets one bind the local side of NFS sockets to a particular
> >>>> IP address.  This can be useful for users on multi-homed systems.
> >>>>
> >>>> This patch must be on top of the previous patch to fix the IPv6 address
> >>>> comparison or it will not work.
> >>>>
> >>>> Comments and suggestions welcome...I'll incorporate those and post an
> >>>> official signed-off patch after that.
> >>>>
> >>>> Thanks,
> >>>> Ben
> >>>>
> >>>
> >>> The code in nfs_callback_authenticate is going to break NFSv4 callbacks.
> >>> Callbacks are sent to the -oclientaddr address, not srcaddr (btw, I
> >>> really dislike that new boolean argument to nfs_find_client(). If you
> >>> don't want to compare the source address, then have the caller pass a
> >>> NULL pointer).
> >>
> >>
> >> Would this fix the callback issue you speak of?  The idea is to
> >> use source and dest to match if it exists, but if we find one
> >> where server address matches and srcaddr isn't specified,
> >> then we will use that.
> >
> > No. As I said, it needs to match the clientaddr argument, not the
> > srcaddr.
> >
> > The problem is that you are now potentially introducing cases where the
> > server may have multiple combinations of clientaddr and srcaddr.
> 
> Ok, so what do you think about allowing a flag to bind() to clientaddr
> instead of having the separate srcaddr option?

That might be slightly less intrusive, but I'm still unconvinced it is
something we need to support in the upstream kernels.

Cheers
  Trond