How to cleanup cisco dhcp inserted attributes ?

[Jarkko Torppa]

What would be good way to cleanup attributes that are generated by  
cisco's dhcp snooping/inserting ?

  User-Name = "\001\026harjuniitty-ftth-sw1_6"
  ADSL-Agent-Circuit-Id = "\001\026harjuniitty-ftth-sw1_6"
  ADSL-Agent-Remote-Id = "\001\024harjuniitty-ftth-sw1"

Id like to strip that type 0x01 and length from data so that I would  
have "harjuniitty-ftth-sw1_6" for user-name.

I did'nt see anything obivous in unlang that could do this, and  
created hack in rlm_preprocess.c

As a background, cisco switch snoops dhcp-packet and inserts it's name  
and port into Option82 of dhcp-packet which is then forwarded to dhcp- 
relay that first authenticates that request via radius server.