Strange Error message SIOCGIFCONF Invalid argument

[Richard Smits]

Glenn Satchell wrote:
>> Date: Thu, 20 Sep 2007 12:45:20 +0200
>> From: "R.Smits" <R.Smits at tudelft.nl>
>> To: dhcp-users at isc.org
>> Subject: Strange Error message SIOCGIFCONF Invalid argument
>>
>> Hello,
>>
>> We have a Solaris 9 box running ISC 3.03
>>
>> We have 64 trunked virtual network interfaces. When we try to make
>> another one, and start the dhcp server, the messages file says :
>>
>> ioctl: SIOCGIFCONF: Invalid argument
>>
>> The dhcp server exits with this error message. What does this mean ?
>>
>> Greetings... Richard Smits
>> TU-Delft
> 
> A quick google with that error message shows that Solaris returns
> invalid argument if the size of the buffer passed in the ioctl() call
> is not big enough to hold the data for all the interfaces.
> 
> The string SIOCGIFCONF occurs in only one source file,
> common/discover.c. In this file this string is used several times in
> the subroutine discover_interfaces(). It starts with a 2048 byte
> buffer, but if it gets an error it increases the size and tries again.
> At least this is the way it is supposed to work in 3.0.4 and 3.0.5. I
> don't have a copy of the 3.0.3 source code handy to see if this
> behaviour is in that version. I know it was added somewhere along the
> years.
> 
> First step would be to try a newer release to see if the behaviour changes.
> 
> Otherwise you could increase the size of the buffer until it works.
> 
> regards,
> -glenn
> 

Ah ok.... this is a good explanation.

> Otherwise you could increase the size of the buffer until it works.

Ok, but how do you do this ? We will try a newer version, but a quick
fix would be better :-)

Greetings, and thank you for your help...

Richard