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Message-ID: <4831E3E4.5060700@hp.com>
Date: Mon, 19 May 2008 16:32:36 -0400
From: Brian Haley <brian.haley@...com>
To: Chuck Lever <chuck.lever@...cle.com>
Cc: Jeff Garzik <jeff@...zik.org>, netdev@...r.kernel.org
Subject: Re: [PATCH 0/4] RFC: raw IPv6 address parsing in NFS client
Chuck Lever wrote:
>>>> 2) an interface name rather than index should be used
>>> If you give a raw IPv6 address with an interface name to mount.nfs,
>>> it passes the whole thing to getaddrinfo(3) which maps the name to an
>>> index. The address with index is then passed on to the kernel via
>>> mount(2) via the normal "addr=" mount option.
>>> Is there a way the kernel can do that mapping for itself?
>>
>> The kernel certainly knows the interface names... IMO that is a bit
>> more natural than interface index.
>>
>> You certainly do not want to _store_ interface index or encourage its
>> use, since it might change during runtime if network interfaces change.
>
> We are storing the address of the server in a struct sockaddr_storage,
> and that would include a scope ID if it were an AF_INET6 address. We
> are also storing the server hostname in /etc/mtab for umount.nfs to use
> later, and that hostname may be a raw IPv6 address.
>
> So it sounds like we need to store the device name separately in the
> kernel's NFS and RPC data structures and do the devname to scope_id
> conversion during the transport's socket connect. Oy.
Hmm, the kernel already stores interface indexes in structures today,
for example if you use SO_BINDTODEVICE, or join a Multicast group.
Seems to me that's perfectly valid to do, with the caveat that the
device might change it's index.
-Brian
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