Fw: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join on same multicast-group dont return EINVAL

Fw: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join on same multicast-group dont return EINVAL

[Stephen Hemminger]

Begin forwarded message:

Date: Wed, 5 May 2010 09:48:40 GMT
From: bugzilla-daemon@bugzilla.kernel.org
To: shemminger@linux-foundation.org
Subject: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join on same multicast-group dont return EINVAL


https://bugzilla.kernel.org/show_bug.cgi?id=15907

           Summary: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join
                    on same multicast-group dont return EINVAL
           Product: Networking
           Version: 2.5
    Kernel Version: 2.6.34-rc6
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: IPV4
        AssignedTo: shemminger@linux-foundation.org
        ReportedBy: mail@fholler.de
        Regression: No


Created an attachment (id=26225)
 --> (https://bugzilla.kernel.org/attachment.cgi?id=26225)
asm+ssm join test program

When an SSM IP_ADD_SOURCE_MEMBERSHIP is done after an ASM IP_ADD_MEMBERSHIP
join on the same group(& same interface) the setsockopt operation should return
EINVAL.

The linux implementation returns successfull



https://www3.tools.ietf.org/html/rfc3678#section-4.1.3

I attached an simple C test program.

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Re: Fw: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join on same multicast-group dont return EINVAL

[David Stevens]

This particular failure  may be  just a matter of translating the
EADDRINUSE check in IP_ADD_SOURCE_MEMBERSHIP to
return EINVAL rather than ignoring it. The more general change of
segregating SSM and ASM should go further than that (e.g., a boolean
to tell you which way the membership was added and checking in
all the operations).

The code predates this informational RFC and allows you to
change back and forth between ASM and SSM where it makes
sense (a more liberal interpretation).

Of course, if existing applications are mixing them already, they
would break, and I'm not sure I agree it's a good thing to have
to destroy an existing membership and recreate it if you want to
switch from ASM to SSM.

I can look at this, but not for a few days at least; can review if
someone else does before I do.

                                        +-DLS


netdev-owner@vger.kernel.org wrote on 05/05/2010 08:21:38 AM:

> 
> 
> Begin forwarded message:
> 
> Date: Wed, 5 May 2010 09:48:40 GMT
> From: bugzilla-daemon@bugzilla.kernel.org
> To: shemminger@linux-foundation.org
> Subject: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after 
IP_ADD_MEMBERSHIP 
> join on same multicast-group dont return EINVAL
> 
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=15907
> 
>            Summary: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP 
join
>                     on same multicast-group dont return EINVAL
>            Product: Networking
>            Version: 2.5
>     Kernel Version: 2.6.34-rc6
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: IPV4
>         AssignedTo: shemminger@linux-foundation.org
>         ReportedBy: mail@fholler.de
>         Regression: No
> 
> 
> Created an attachment (id=26225)
>  --> (https://bugzilla.kernel.org/attachment.cgi?id=26225)
> asm+ssm join test program
> 
> When an SSM IP_ADD_SOURCE_MEMBERSHIP is done after an ASM 
IP_ADD_MEMBERSHIP
> join on the same group(& same interface) the setsockopt operation should 
return
> EINVAL.
> 
> The linux implementation returns successfull
> 
> 
> 
> https://www3.tools.ietf.org/html/rfc3678#section-4.1.3
> 
> I attached an simple C test program.
> 
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Re: Fw: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join on same multicast-group dont return EINVAL

[David Stevens]

Dave,
        Do you have an opinion on this one? Linux code (for many years 
now)
allows you to do SSM calls after an ordinary ASM join, and vice-versa. The 
bugzilla
basically wants to see mixing the calls return EINVAL.
        That's not so hard to do, but if existing apps are mixing them, 
they, of
course, will fail. That's the intent of the RFC, but the code predates it 
and
happily converts between ASM and SSM automatically.
        So, I'm guessing the answer is "will not fix," but
it's your call. If you think we want to enforce this, I'll do
a patch.
        The original post is here:

http://marc.info/?l=linux-netdev&m=127307292215281&w=2

                                                        +-DLS

Re: [Bug 15907] New: IP_ADD_SOURCE_MEMBERSHIP after IP_ADD_MEMBERSHIP join on same multicast-group dont return EINVAL

[David Miller]

From: David Stevens <dlstevens@us.ibm.com>
Date: Fri, 7 May 2010 16:50:44 -0700

>         Do you have an opinion on this one? Linux code (for many
> years now) allows you to do SSM calls after an ordinary ASM join,
> and vice-versa. The bugzilla basically wants to see mixing the calls
> return EINVAL.

We can't do that.

It will obviously break existing applications.

Someone please close the bug.