RE: [PATCH v2 01/11] RDMA/CMA: Mark IPv4 addresses correctly when the listener is IPv6

Shachar Raindel
2015-04-21T05:18:18Z

> -----Original Message-----
> From: Or Gerlitz [mailto:gerlitz.or@gmail.com]
> Sent: Monday, April 20, 2015 9:38 PM
>
> On Mon, Apr 20, 2015 at 7:41 PM, Jason Gunthorpe
> <jgunthorpe@obsidianresearch.com> wrote:
> > On Mon, Apr 20, 2015 at 12:03:32PM +0300, Haggai Eran wrote:
> >> From: Yotam Kenneth <yotamke@mellanox.com>
> >>
> >> When accepting a new connection with the listener being IPv6, the
> >> family of the new connection is set as IPv6. This causes
> cma_zero_addr
> >> function to return true on an non-zero address. As a result, the
> wrong
> >> code path is taken. This causes the connection request to be
> rejected,
> >> as the RDMA-CM code looks for the wrong type of device.
> >
> > This description doesn't really make sense as to what the problem is.
> >
> >> @@ -866,12 +866,12 @@ static void cma_save_ip4_info(struct rdma_cm_id
> *id, struct rdma_cm_id *listen_i
> >>
> >> listen4 = (struct sockaddr_in *) &listen_id-
> >route.addr.src_addr;
> >> ip4 = (struct sockaddr_in *) &id->route.addr.src_addr;
> >> - ip4->sin_family = listen4->sin_family;
> >> + ip4->sin_family = AF_INET;
> >
> > If listen_id->route.addr.src_addr.ss_family != AF_INET then it is
> > invalid to cast to sockaddr_in.
> >
> > So listen4->sin_family MUST be AF_INET or this function MUST NOT be
> > called.
> >
> > Forcing to AF_INET cannot be correct here.
>
> Jason, could you take a look @ this thread
> http://marc.info/?t=141589395000004&r=1&w=2 where the authors
> addressed some comments from Sean and he eventually Acked the patch?
>
> > What does this patch have to do with this series?
>
> I believe it's either a pre-patch to address some assumption or
> something they stepped on while testing
>

We stepped upon this issue while testing the containers support we are
Submitting here. When creating a new network namespace, the kernel set
net->ipv6.sysctl.bindv6only to 0. As a result, we got the IPv6 listening
ID accepting IPv4 connection. This is fixed by the above patch.

Thanks,
--Shachar