[j-nsp] dhcp relay fail between VRFs

[Chris Cappuccio]

I have no trouble with dhcp relay between VRFs across MPLS PE routers,
but across VRFs on the same router, the relay daemon fud fails.

If I turn on debugging, I am always getting:

Dec 18 19:49:06 FUD_RTSOCK_MSG_FAILURE: Unable to get prefix match: No such file or directory
Dec 18 19:49:06 reply from 192.168.200.2 no interface for 192.168.204.69
Dec 18 19:49:10 FUD_RTSOCK_MSG_FAILURE: Unable to get prefix match: No such file or directory
Dec 18 19:49:10 reply from 192.168.200.2 no interface for 192.168.204.69

The DHCP server at 192.168.200.2 is assigning 192.168.204.69 and the fud
program is trying to reply directly to it, EVEN THOUGH the dhcp server
is replying to the router's gateway address in the destination subnet, not
directly to the unreachable layer 2 device. fud is trying to resolve
the layer 2 interface based on the assigned IP?? When this happens on
other PE routers, the DHCP server replies to the gateway address and
fud doesn't get involved, the packet just gets forwarded to the remote
router and the relay is completed properly.

The thing is, inet.0 has routes for both 192.168.200.0/24 and 192.168.204.0/24
leaked from their respective VRFs. Routes for each VRF are also leaked to each
other. fud should be able to look up the interface for 192.168.204.69 with no
problem. 

inet.0: 724201 destinations, 1445332 routes (722565 active, 0 holddown, 3213 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.204.64/26  *[Direct/0] 16:05:50
                    > via ge-5/1/6.8
...
pub-vrf.inet.0: 168 destinations, 169 routes (168 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.204.64/26  *[Direct/0] 16:05:50
                    > via ge-5/1/6.8
...
serv1-vrf.inet.0: 530 destinations, 544 routes (530 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.204.64/26  *[Direct/0] 16:05:50
                    > via ge-5/1/6.8

Can anyone help give me a clue about how and where fud looks for interfaces and
routes? It can't be inet.0 that it's looking at. The serv1 vrf is where the
DHCP server lives. The pub vrf is where the client lives. Both vrfs have
routes to the client.

On this same router, any relays within the same VRF work just fine. fud
can find the route, no matter what the VRF is.