[PATCH 0/6] dhcrelay: Some useful DHCPv6 additions

[Bjørn Mork]

Hello,

In case anyone else are interested, here are a few patches for
the DHCPv6 code in dhcrelay. The base is the 4.2.2 release.

We are using these internally for test purposes, simulating a 
DSLAM layer2 relay on Linux. To do this, we needed to add the 
RFC6221 support.  And we also needed some way to configure 
D6O_SUBSCRIBER_ID and D6O_REMOTE_ID options per downstream 
interface.

The -l downstream interface option was a bit overloaded before
these patches, so we just made it worse :-)  I guess this needs
some cleanup if going into production.  Maybe it's time for a
configuration file for dhcrelay as well?

Tip: configuring a Linux host for layer2 DHCP6 relaying is
pretty straight forward:

1) configure a bridge with all your upstream and downstream
   interfaces:

    brctl addbr br0
    brctl addif br0 eth0
    brctl addif br0 eth1
    brctl addif br0 eth2
   [etc]


2) route anything looking like DHCPv6 or addressed to the bridge:

    ebtables  -t broute -A BROUTING -p IPv6 --ip6-proto udp --ip6-dport 546:547 -j DROP
    ebtables  -t broute -A BROUTING -p IPv6 --ip6-dst fe80::f00 -j DROP
    ebtables  -t broute -A BROUTING -p IPv6 --ip6-dst fe80::f01 -j DROP
    ebtables  -t broute -A BROUTING -p IPv6 --ip6-dst fe80::f02 -j DROP
  [etc]

  where fe80::f0X are the link local addresses of ethX etc. (you probably need to add 
  *all* IPv6 addresses on ethX this way, but you don't need to have any global addresses
  there)


3) run dhcrelay in RFC6221 mode (with the patches below):

     dhcrelay -6 -L -l eth1 -l eth2 -u eth0


The above of course assumes clients on eth1 and eth2 and a DHCPv6 
server (or another relay) on eth0


Enjoy!



Bjørn Mork (6):
  dhcrelay: Refactor DHCPv6 interface-id adding code
  dhcrelay: Adding D6O_REMOTE_ID support to DHCPv6 relay
  dhcrelay: Use network byte order for the interface id value
  dhcrelay: Print interface name in DHCPv6 downstream log messages
  dhcrelay: Support RFC6221 Lightweight DHCPv6 Relay Agent operation
  dhcrelay: Add D6O_SUBSCRIBER_ID to DHCPv6 relayed packets

 relay/dhcrelay.8 |   28 +++++++++--
 relay/dhcrelay.c |  143 +++++++++++++++++++++++++++++++++++++----------------
 2 files changed, 124 insertions(+), 47 deletions(-)

-- 
1.7.2.5