IPv6 Patch

[Brian Aker]

Hi!

On Jan 29, 2008, at 11:54 PM, Tomash Brechko wrote:

> That's exactly the point.  The user have the control with the -l
> option.  And if I specify some name, I expect it to be resolved to all
> addresses (for one address I would simply specify it as is).  I doubt
> Drepper's paper is wrong with this respect.  Also, with IPv6 a single

Drepper's paper is not wrong, it just does not think through the  
actions of poor DNS entries.

One thought I had this morning was perhaps toss an error if ai->next  
shows that there are multiple binding addresses.

> AI_ADDRCONFIG is required to skip the addresses when they are reported
> by DNS but the host doesn't bind them to any interface.  As for the
> rest, I didn't mean you should combine UPD and TCP.  What I mean is
> that there's no point to disable IPv6 for UDP as you did, and no point
> to explicitly specify IPPROTO_* along with SOCK_*.

OSX 10.5 has issues with IPv6 and binding for UDP right now, which is  
why I left it that way (but then 10.5).

I've never found an authoritative that says you can get away with just  
setting IPPROT and not SOCK (or vice versa).

>>> It should be
>>>
>>>     if (error != 0) {
>>>         if (error != EAI_SYSTEM)
>>>             fprintf(stderr, "getaddrinfo(): %s\n",
>>> gai_strerror(error));
>>>         else
>>>             perror("getaddrinfo()");
>>>
>>>         return -1;
>>>     }
>>
>> All errors returned by getaddrinfo() are handled by gai_strerror().
>> Running perror in the way you suggest above will get you a haphazard
>> message of "SUCCESS" from perror(). Just let the error fall to
>> gai_strerror().
>
> "SUCCESS" can't be ever reported, the code above runs perror() only
> when getaddrinfo() returns EAI_SYSTEM.  gai_strerror(EAI_SYSTEM) will
> return "System error", while perror() will be more specific.  Here's
> what man page says:
>
>       EAI_SYSTEM
>              Other system error, check errno for details.
>
> And the code above "checks" errno with perror().

Ok, extra error information can not hurt (though I suspect some  
systems will report SUCCESS via this).

>>> You have lots of premature returns where you better to do
>>> freeaddrinfo() too, just for the case ;).
>>
>>
>> That is how the program is structured. Look at how the other exit
>> points are done.
>
> Exactly because of this.  On other exit points the code is careful to
> close the socket, so you should do your cleanup as well.


Ok.

Cheers,
	-Brian

--
_______________________________________________________
Brian "Krow" Aker, brian at tangent.org
Seattle, Washington
http://krow.net/                     <-- Me
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_______________________________________________________
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