Re: [PATCH for-next] RDMA/CMA: Mark IPv4 addresses correctly when the listener is IPv6

[Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

On 11/16/2014 11:04 AM, Shachar Raindel wrote:
>
>> -----Original Message-----
>> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-
>> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Hefty, Sean
>> Sent: Thursday, November 13, 2014 6:24 PM
>> To: Or Gerlitz
>> Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Roland Dreier; Yotam Kenneth
>> Subject: RE: [PATCH for-next] RDMA/CMA: Mark IPv4 addresses correctly
>> when the listener is IPv6
>>
>>> From: Yotam Kenneth <yotamke-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>>>
>>> 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.
>>>
>>> Since copying the ip address is done in different function depending
>>> on the family (cma_save_ip4_info/cma_save_ip6_info) this is fixed by
>>> hard coding the family of the IP address according to the function.
>>>
>>> Signed-off-by: Yotam Kenneth <yotamke-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>>> Signed-off-by: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>>> ---
>>>   drivers/infiniband/core/cma.c |    8 ++++----
>>>   1 files changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/infiniband/core/cma.c
>> b/drivers/infiniband/core/cma.c
>>> index d570030..6e5e11c 100644
>>> --- a/drivers/infiniband/core/cma.c
>>> +++ b/drivers/infiniband/core/cma.c
>>> @@ -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;
>>>   	ip4->sin_addr.s_addr = hdr->dst_addr.ip4.addr;
>>>   	ip4->sin_port = listen4->sin_port;
>>>
>>>   	ip4 = (struct sockaddr_in *) &id->route.addr.dst_addr;
>>> -	ip4->sin_family = listen4->sin_family;
>>> +	ip4->sin_family = AF_INET;
>>>   	ip4->sin_addr.s_addr = hdr->src_addr.ip4.addr;
>>>   	ip4->sin_port = hdr->port;
>>>   }
>>> @@ -883,12 +883,12 @@ static void cma_save_ip6_info(struct rdma_cm_id
>> *id,
>>> struct rdma_cm_id *listen_i
>>>
>>>   	listen6 = (struct sockaddr_in6 *) &listen_id->route.addr.src_addr;
>>>   	ip6 = (struct sockaddr_in6 *) &id->route.addr.src_addr;
>>> -	ip6->sin6_family = listen6->sin6_family;
>>> +	ip6->sin6_family = AF_INET6;
>>>   	ip6->sin6_addr = hdr->dst_addr.ip6;
>>>   	ip6->sin6_port = listen6->sin6_port;
>>>
>>>   	ip6 = (struct sockaddr_in6 *) &id->route.addr.dst_addr;
>>> -	ip6->sin6_family = listen6->sin6_family;
>>> +	ip6->sin6_family = AF_INET6;
>>>   	ip6->sin6_addr = hdr->src_addr.ip6;
>>>   	ip6->sin6_port = hdr->port;
>> I can't say that I understand what the problem is or how the change
>> fixes it.  Is listen4->sin_port above not AF_INET?  If that's the case,
>> then aren't we still taking the wrong code path and just masking some
>> bug further up in the code path?
>
> An IPv6 listener socket can accept IPv4 connection, especially
> when listening to the "any" interface. This behavior is
> configurable with the net.ipv6.bindv6only sysctl flag. In
> RDMA-CM, we use this flag as the baseline value for the CM-ID
> flag "afonly". If afonly is set to 0, a listening RDMA-CM ID for
> IPv6 any address will happily accept an IPv4 connection. The IP
> addresses saved in cma_save_ip[46]_info are only used internally
> in the RDMA-CM code for selecting the appropriate device for
> answering and sending a reply. As such, there is no problem with
> hard coding the appropriate address family in the functions.
>
>

Hi Sean,

Any comment? can you please ack the patch or continue the discussion?


Or.
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