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As foundation, we'll need some patches that have just hit Trond's git tree: commit c98451bdb2f3e6d6cc1e03adad641e9497512b49 Author: Frank van Maarseveen <frankvm@frankvm.com> Date: Mon Jul 9 22:25:29 2007 +0200 NLM: fix source address of callback to client Use the destination address of the original NLM request as the source address in callbacks to the client. Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> commit d3bc9a1deb8964d774af8535814cb91bf8f6def0 Author: Frank van Maarseveen <frankvm@frankvm.com> Date: Mon Jul 9 22:23:35 2007 +0200 SUNRPC client: add interface for binding to a local address In addition to binding to a local privileged port the NFS client should allow binding to a specific local address. This is used by the server for callbacks. The patch adds the necessary interface. Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> commit a97476926ec061f90b77da478620ea6dc71a3237 Author: Frank van Maarseveen <frankvm@frankvm.com> Date: Mon Jul 9 22:21:39 2007 +0200 SUNRPC server: record the destination address of a request Save the destination address of an incoming request over TCP like is done already for UDP. It is necessary later for callbacks by the server. Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> commit 96802a095171f5b35cf0e1e0d4be943e6696a253 Author: Frank van Maarseveen <frankvm@frankvm.com> Date: Sun Jul 8 13:08:54 2007 +0200 SUNRPC: cleanup transport creation argument passing Cleanup argument passing to functions for creating an RPC transport. Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> ...I'm thinking these will probably hit 2.6.23. Technically, I think we only really need: 96802a095171f5b35cf0e1e0d4be943e6696a253 d3bc9a1deb8964d774af8535814cb91bf8f6def0 ...but these were proposed as a set. We'll also need a small patch on top of these that takes advantage of the new xs_bind interface.
Created attachment 159189 [details] patch -- bind nfsv4 sockets to clientaddr This patch makes it so that NFSv4 sockets are automatically bound to the clientaddr callback address. It makes sense to me that the socket should use the same src address as the callback, though perhaps there are reasons not to do so. This patch relies on the 4 patches in the previous comment. Cursory testing indicates that it works. I'll write this up and propose upstream soon.
Similar patch posted to nfs@sourceforge.net and nfsv4@linux-nfs.org: Subject: [PATCH] have NFSv4 nfs sockets bind to the callback address Patch I posted is slightly different -- it does extra initialization of the sin_client struct. I'm not sure that's needed, but it shouldn't hurt. Awaiting feedback...
Trond pointed out that the callback address need not necessarily be on any interface on the machine (consider a NAT'ed setup). So this scheme won't work at all. If this is to be done, it's going to require a new mount option (srcaddr or something maybe). I need to have a closer look at Chuck's string option patches and see how best to do this.
Created attachment 159363 [details] patch -- add new mount option "srcaddr=" This is a first (untested) pass at a kernel patch for this. It adds a new srcaddr= mount option. Currently, it doesn't do any validation of the address at all, so that will likely need to be added in before it goes upstream.
I've been doing some work on this today. I've gotten something written (but untested as of yet). I've been doing it against current upstream now, which means I'm integrating it in with Chuck's string-based option patches. This is most likely a 2.6.24-ish patch at best anyway. I don't see this going in before f8 most likely anyway...
Created attachment 159516 [details] patch -- add new srcaddr option Newest patch that I'm looking at. This should add the srcaddr option, and make it so that the local socket it bound to it. This is still very experimental. Some nits: 1) I don't like all of the copying of the address from struct to struct, but I don't see a good way to avoid it. 2) I don't like messing with includes. nfs4_mount.h doesn't know anything about sockaddr structs, so I had to include linux/socket.h from it. There may be a better way to do it that doesn't require this.
Note that there are also some v6 patches that are a WIP upstream too and this may well affect them. So it's quite possible we'll need to respin this to be more transport agnostic.
Patch seems to work. I tested it using a simple C program that passed hardcoded strings into a mount() call, and looking at the socket created in netstat -an. I'm going to hold off on proposing this upstream just yet, however. The patches for string-based mount options seem to be in Linus' tree now, but we still don't have mount.nfs[4] programs that pass strings as mount options. This patch adds fields to nfs_mount_data/nfs4_mount_data and so the versions of those structs need to be revved. That's always a painful experience, so it's prob best to wait until all of the string-based stuff is actually upstream.
Jeff, It appears to be so from a quick, inexpert look at the patch, but to confirm this would be useful for both NFSv3 and NFSv4?
Yes, the new option should work regardless of NFS version.
Upstream has merged a good portion of Chuck Lever's IPv6 patches. The patches in this BZ will probably no longer apply and will need to be respun. I'll likely also have to make the patch accept an IPv6 source address as well in order to gain upstream acceptance.