[PATCH 2/2] ipv4: make do_ip_setsockopt for IP_MULTICAST_IF support ip_mreq struct

[PATCH 2/2] ipv4: make do_ip_setsockopt for IP_MULTICAST_IF support ip_mreq struct

[Xiaotian Feng]

ip_mreq and ip_mreqn is almost the same, and do_ip_setsockopt for IP_MULTICAST_IF
part supported ip_mreqn struct. This patch adds support for ip_mreq struct.

Signed-off-by: Marc Milgram <mmilgram@redhat.com>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: David S. Miller <davem@davemloft.net>
---
 net/ipv4/ip_sockglue.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 5a29dce..1e8d026 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -612,11 +612,16 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 		 */
 
 		err = -EFAULT;
+		memset(&mreq, 0, sizeof(mreq));
+
 		if (optlen >= sizeof(struct ip_mreqn)) {
 			if (copy_from_user(&mreq, optval, sizeof(mreq)))
 				break;
+		} else if (optlen >= sizeof(struct ip_mreq)) {
+			if (copy_from_user(&mreq, optval,
+					   sizeof(struct ip_mreq)))
+				break;
 		} else if (optlen >= sizeof(struct in_addr)) {
-			memset(&mreq, 0, sizeof(mreq));
 			if (copy_from_user(&mreq.imr_address, optval,
 					   sizeof(struct in_addr)))
 				break;
-- 
1.6.2.5

Re: [PATCH 2/2] ipv4: make do_ip_setsockopt for IP_MULTICAST_IF support ip_mreq struct

[Shan Wei]

Xiaotian Feng wrote, at 09/17/2009 01:20 PM:
> ip_mreq and ip_mreqn is almost the same, and do_ip_setsockopt for IP_MULTICAST_IF
> part supported ip_mreqn struct. This patch adds support for ip_mreq struct.
> 

It's not meaning to support the ip_mreq struct, the imr_multiaddr member
never be used by the IP_MULTICAST_IF.

In addition, using the option normally like this: 
  struct in_addr interface_addr;
  setsockopt (socket, IPPROTO_IP, IP_MULTICAST_IF, &interface_addr, sizeof(interface_addr));
 
Do your patch suggest using the option like this?
  struct ip_mreq  mreq;
  setsockopt (socket, IPPROTO_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq));
 

Best Regards
-----
Shan Wei

Re: [PATCH 2/2] ipv4: make do_ip_setsockopt for IP_MULTICAST_IF support ip_mreq struct

[Danny Feng]

On 09/17/2009 05:16 PM, Shan Wei wrote:
> Xiaotian Feng wrote, at 09/17/2009 01:20 PM:
>> ip_mreq and ip_mreqn is almost the same, and do_ip_setsockopt for IP_MULTICAST_IF
>> part supported ip_mreqn struct. This patch adds support for ip_mreq struct.
>>
>
> It's not meaning to support the ip_mreq struct, the imr_multiaddr member
> never be used by the IP_MULTICAST_IF.
>
> In addition, using the option normally like this:
>    struct in_addr interface_addr;
>    setsockopt (socket, IPPROTO_IP, IP_MULTICAST_IF,&interface_addr, sizeof(interface_addr));
>
> Do your patch suggest using the option like this?
>    struct ip_mreq  mreq;
>    setsockopt (socket, IPPROTO_IP, IP_MULTICAST_IF,&mreq, sizeof(mreq));
>
In fact, current implemetation supports:

struct ip_mreqn mreqn;
setsockopt(socket, IPPROTO_IP, IP_MULTICAST_IF, &mreqn, sizeof(mreqn));

Then why not support mreq?
>
> Best Regards
> -----
> Shan Wei
>

Re: [PATCH 2/2] ipv4: make do_ip_setsockopt for IP_MULTICAST_IF support ip_mreq struct

[Alexey Kuznetsov]

Hello!

On Thu, Sep 17, 2009 at 05:19:16PM +0800, Danny Feng wrote:
> In fact, current implemetation supports:
> 
> struct ip_mreqn mreqn;
> setsockopt(socket, IPPROTO_IP, IP_MULTICAST_IF, &mreqn, sizeof(mreqn));
> 
> Then why not support mreq?

Because support of ip_mreqn makes sense (it user interface index)
and support of ip_mreq, which does not contain interface index,
does not. "Polymorphic" IP_MULTICAST_IF was a stupid mistake (mine),
which should not grow like a tumor.

Ack to patch #1, nack to #2.

Alexey