dccifd and ipv6 on linux

Vincent Schonau vince@niet.net
Tue Mar 15 15:48:28 UTC 2005

Vernon Schryver wrote:
>>From: Vincent Schonau 
>>dccifd on my system doesn't like ipv6 addresses:
>>[ from a dccifd log file ]
>>unrecognized IP address "2001:888:11d4:32::1S"
> That might be due to a bogus line that I somehow added to dcclib/clnt_send.c
> See the attached context-diff patch about removing 
>       memcpy(&ap->ip, &su.ipv4.sin_addr, sizeof(ap->ip));

I don't think removing that line fixed the problem.

> On the other hand, I don't see why dccifd should care about that problem.
> Where does IPv6 find that IPv6 address?  In a mail message?

It is passed to dccif as the $clnt_addr parameter in the sample 
dccifd/dccif.pl. On closer examination, I remember that I disabled the 
inet_aton($clnt_addr) test there, so the above IP is being passed to 
dccifd as a string (which, since it _is_ a valid ipv6 address, seems the 
right thing to do from the dccif manpage).

Should I be rewriting the IPv6 address to one of the more verbose forms 
before passing it to dccifd?

This issue is not dependant on ipv6 support being compiled into dcc?

>>So, in a first-guess effort to fix this, I tried 'cdcc ipv6 on':
>> > Note that this version of the DCC was built without IPv6 support.
>> > IPv6 switch not changed.
>>My Linux systems (Fedora Core 3, 2.6.10 kernel) all have working IPv6 
>>implementations. I do not understand 'configure' magic well enough to 
>>understand why the ipv6 test fails on my systems.
> What does ./configure say on such a system?  There should be something
> about whatever doesn't seem to support IPv6.

[ ... ]
checking run directory... (cached) /var/run
checking for getipnodebyname... (cached) no
checking for IPv6... no getipnodebyname()
checking for Rsendto... (cached) no
creating ./config.status

Indeed, I can find no reference to getipnodebyname() on my sytem.

> As far as I know, the DCC IPv6 support is complete, but it gets little
> or no use and so it is rather rough.
> Right now I'm running dccd on FreeBSD with IPv6 turned on.  But that
> only shows that localhost IPv6 works.

If I can get it to compile here, we could experiment some more, since 
dcc.niet.net is also reachable via ipv6.

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