IP_MULTICAST_IF getsockopt man part

IP_MULTICAST_IF getsockopt man part

[Jiri Pirko]

Hi.

<quote>
IP_MULTICAST_IF (since Linux 1.2)
	              Set the local device for a multicast socket.
		      Argument is an ip_mreqn or ip_mreq structure
		      similar to IP_ADD_MEMBERSHIP.
</quote>

That is not true. Setsockopt recognizes only ip_mreqn and in_addr. I
made patch which makes it recognize ip_mreq as well. So that would be
probably ok.
http://patchwork.ozlabs.org/patch/156815/

On the other hand, getsockopt works only with in_addr. That I think is
good behaviour but manpages here needs to be corrected in this way (read
part needs to be added here)

Thanks!

Jirka
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Re: IP_MULTICAST_IF getsockopt man part

[Michael Kerrisk (man-pages)]

On Fri, May 4, 2012 at 9:00 PM, Jiri Pirko <jpirko@redhat.com> wrote:
> Hi.
>
> <quote>
> IP_MULTICAST_IF (since Linux 1.2)
>                      Set the local device for a multicast socket.
>                      Argument is an ip_mreqn or ip_mreq structure
>                      similar to IP_ADD_MEMBERSHIP.
> </quote>
>
> That is not true. Setsockopt recognizes only ip_mreqn and in_addr. I
> made patch which makes it recognize ip_mreq as well. So that would be
> probably ok.
> http://patchwork.ozlabs.org/patch/156815/
>
> On the other hand, getsockopt works only with in_addr. That I think is
> good behaviour but manpages here needs to be corrected in this way (read
> part needs to be added here)

Jirka,

I'm having trouble to understand what you mean. Perhaps it would be
simplest if you showed your proposed replacement text for the text
quoted above.

Thanks,

Michael



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/

Re: IP_MULTICAST_IF getsockopt man part

[Jiri Pirko]

Sat, May 05, 2012 at 01:57:35PM CEST, mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>On Fri, May 4, 2012 at 9:00 PM, Jiri Pirko <jpirko-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>> Hi.
>>
>> <quote>
>> IP_MULTICAST_IF (since Linux 1.2)
>>                      Set the local device for a multicast socket.
>>                      Argument is an ip_mreqn or ip_mreq structure
>>                      similar to IP_ADD_MEMBERSHIP.
>> </quote>
>>
>> That is not true. Setsockopt recognizes only ip_mreqn and in_addr. I
>> made patch which makes it recognize ip_mreq as well. So that would be
>> probably ok.
>> http://patchwork.ozlabs.org/patch/156815/
>>
>> On the other hand, getsockopt works only with in_addr. That I think is
>> good behaviour but manpages here needs to be corrected in this way (read
>> part needs to be added here)
>
>Jirka,
>
>I'm having trouble to understand what you mean. Perhaps it would be
>simplest if you showed your proposed replacement text for the text
>quoted above.

<orig>
IP_MULTICAST_IF (since Linux 1.2)
Set the local device for a multicast socket. Argument is an ip_mreqn
or ip_mreq structure similar to IP_ADD_MEMBERSHIP.
</orig>
<new>
IP_MULTICAST_IF (since Linux 1.2)
Set or read the local device for a multicast socket.
Argument for set is an ip_mreqn or ip_mreq or addr_in structure.
Argument for read is an addr_in structure.
</new>


Jirka



>
>Thanks,
>
>Michael
>
>
>
>-- 
>Michael Kerrisk
>Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
>Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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Re: IP_MULTICAST_IF getsockopt man part

[Michael Kerrisk (man-pages)]

[CC += Magnus, who made a related reported soon after yours.]

Jiri,

On 05/09/2012 11:34 AM, Jiri Pirko wrote:
> Sat, May 05, 2012 at 01:57:35PM CEST, mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>> On Fri, May 4, 2012 at 9:00 PM, Jiri Pirko <jpirko-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>>> Hi.
>>>
>>> <quote>
>>> IP_MULTICAST_IF (since Linux 1.2)
>>>                      Set the local device for a multicast socket.
>>>                      Argument is an ip_mreqn or ip_mreq structure
>>>                      similar to IP_ADD_MEMBERSHIP.
>>> </quote>
>>>
>>> That is not true. Setsockopt recognizes only ip_mreqn and in_addr. I
>>> made patch which makes it recognize ip_mreq as well. So that would be
>>> probably ok.
>>> http://patchwork.ozlabs.org/patch/156815/
>>>
>>> On the other hand, getsockopt works only with in_addr. That I think is
>>> good behaviour but manpages here needs to be corrected in this way (read
>>> part needs to be added here)
>>
>> Jirka,
>>
>> I'm having trouble to understand what you mean. Perhaps it would be
>> simplest if you showed your proposed replacement text for the text
>> quoted above.
> 
> <orig>
> IP_MULTICAST_IF (since Linux 1.2)
> Set the local device for a multicast socket. Argument is an ip_mreqn
> or ip_mreq structure similar to IP_ADD_MEMBERSHIP.
> </orig>
> <new>
> IP_MULTICAST_IF (since Linux 1.2)
> Set or read the local device for a multicast socket.
> Argument for set is an ip_mreqn or ip_mreq or addr_in structure.
> Argument for read is an addr_in structure.
> </new>

Long after the fact: I've amended the man page text to read:

       IP_MULTICAST_IF (since Linux 1.2)
              Set  the local device for a multicast socket.  The argu‐
              ment for setsockopt(2) is an ip_mreqn  or  (since  Linux
              3.5)  ip_mreq structure similar to IP_ADD_MEMBERSHIP, or
              an in_addr  structure.   (The  kernel  determines  which
              structure  is  being  passed based on the size passed in
              optlen.)  For getsockopt(2), the argument is an  in_addr
              structure.

Cheers,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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