Extracting interface-id from within a relayed dhcpv6 message ...

[Terry Sweetser]

Hi List,

I have a request packet arriving with contents "RELAY-MSG" containing 
data I can to verify and use in a 'host-identifier option' line.

The option I want to extract is the 15 character long interface-id, 
which is 1 relay encapsulation deep in the packet.

Very much like:
host-identifier option /dhcp6.interface-id/ "BIGSTRING";

However I can't find any option to extract data from the inner relayed 
messages.

(That "BIGSTRING" is added by the NSP to allow me to 'authenticate' the 
end-user by sub-interface on a cisco router.)

Suggestions? Solutions?


Jan 30 05:59:17.900: IPv6 DHCP: detailed packet contents
Jan 30 05:59:17.900:   src 2401:A400:100:BEEF::B4B5:80FC
Jan 30 05:59:17.900:   dst 2401:A400:80:F00D::DEAD (GigabitEthernet0/0.89)
Jan 30 05:59:17.900:   type RELAY-FORWARD(12), hop 1
Jan 30 05:59:17.900:   link 2401:A400:401E:0:3573::1
Jan 30 05:59:17.900:   peer FE80::FE75:16FF:FEE5:2DFD
Jan 30 05:59:17.900:   option RELAY-MSG(9), len 160
Jan 30 05:59:17.900:     type RELAY-FORWARD(12), hop 0
Jan 30 05:59:17.900:     link ::
Jan 30 05:59:17.900:     peer FE80::FE75:16FF:FEE5:2DFD
*Jan 30 05:59:17.900:     option INTERFACE-ID(18), len 15**
**Jan 30 05:59:17.900:       0x415643393939393930303033333738**
*Jan 30 05:59:17.900:     option RELAY-MSG(9), len 103
Jan 30 05:59:17.904:       type RENEW(5), xid 8834423
Jan 30 05:59:17.904:       option CLIENTID(1), len 10
Jan 30 05:59:17.904:         00030001FC7516E52DFD
Jan 30 05:59:17.904:       option SERVERID(2), len 14
Jan 30 05:59:17.904:         0001000117A289CDFE0EB012302B
Jan 30 05:59:17.904:       option RECONF-ACCEPT(20), len 0
Jan 30 05:59:17.904:       option ELAPSED-TIME(8), len 2
Jan 30 05:59:17.904:         elapsed-time 0
Jan 30 05:59:17.904:       option ORO(6), len 8
Jan 30 05:59:17.904: DNS-SERVERS,DOMAIN-LIST,SNTP-ADDRESS,RECONF-ACCEPT
Jan 30 05:59:17.904:       option IA-PD(25), len 41
Jan 30 05:59:17.904:         IAID 0x00000000, T1 187, T2 300
Jan 30 05:59:17.904:         option IAPREFIX(26), len 25
Jan 30 05:59:17.904:           preferred 375, valid 600, prefix 
2401:A400:401E:3570::/60
*Jan 30 05:59:17.904:   option INTERFACE-ID(18), len 4**
**Jan 30 05:59:17.904:     0x0000007C**
*

-- 
about.me/terry.sweetser
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20130130/4d3cdb4e/attachment.html>