server sends fqdn option in wrong format

[Ron Broersma]

Correction, inline...

On May 1, 2012, at 8:34 AM, Ron Broersma wrote:

> I'm using DHCPv6 to assign IPv6 addresses and names to clients.  I've configured the server to send the FQDN in response to an FQDN option request (option 39).
> 
> Example host declaration:
> 
> host library3.sd {
> 	hardware ethernet 84:2b:2b:97:03:27;
> 	fixed-address6 2001:480:10:62::1086;
> 	option dhcp6.fqdn "library3.sd.spawar.navy.mil"; 
> } 
> 
> When the server sends the FQDN option in response to a FQDN option request option, the server is not formatting it correctly.   The flags field is totally missing, and the domain name is not encoded in proper "on-the-wire" format (in accordance with RFC 3315 section 8).
> 
> Packet contents for this option looks like this...
> 
> (interpreted by wireshark)
> 
>            Fully Qualified Domain Name
>                option type: 39
>                option length: 27
>                0110 1... = Reserved: 0x0d
>                .... .1.. = N: N bit set
>                .... ..0. = O: O bit cleared
>                .... ...0 = S: S bit cleared
>                Malformed DNS name record (MS Vista client?)
> 
> 0100  80 00 10 00 04 00 00 00 00 00 00 00 03 00 27 00   ..............'.
> 0110  1b 6c 69 62 72 61 72 79 33 2e 73 64 2e 73 70 61   .library3.sd.spa
> 0120  77 61 72 2e 6e 61 76 79 2e 6d 69 6c               war.navy.mil
> 
> Start at byte 113.  0027 = (option) 39.  001b = (length) 27 (should be 28, to include flags).
> Byte 121 should be the flags, but instead it is the first letter of the domain name ('l').
> The domain is separated by periods instead of lengths (not encoded).

Sorry, I counted the offsets wrong.  It is byte 010d where this starts.  The flags should be at 0111, but instead is the first letter of the domain name ('l').  Still a bug.

--Ron