Steve's quick list of things that need finishing off:
[they are in no particular order and range from the trivial to the long winded]

 o Proper timeouts on each neighbour (in routing mode) rather than
   just the 60 second On-Ethernet cache value.

 o Support for X.25 linklayer

 o Support for DDCMP link layer

 o The DDCMP device itself

 o PPP support (rfc1762)

 o Lots of testing with real applications

 o Verify errors etc. against POSIX 1003.1g (draft)

 o Using send/recvmsg() to get at connect/disconnect data (POSIX 1003.1g) 
   [maybe this should be done at socket level... the control data in the
    send/recvmsg() calls should simply be a vector of set/getsockopt()
    calls]

 o check MSG_CTRUNC is set where it should be.

 o Start to hack together user level software and add more DECnet support
   in ifconfig for example. 

 o Test adding/deleting of routes

 o Test route lookup

 o Test /proc/net/decnet_route route listing works correctly (maybe I'll
   change the format of this file... atm its very similar to the IPv4 route
   file)

 o Find all the commonality between DECnet and IPv4 routing code and extract 
   it into a small library of routines. [probably a project for 2.5.xx]

 o Test ip_gre tunneling works... it did the last time I tested it and it
   will have to if I'm to test routing properly.

 o Hello messages should be generated for each primary address on each
   interface.

 o Add the routing message grabbing netfilter module [written, tested,
   awaiting merge]

 o Add perfect socket hashing - an idea suggested by Paul Koning [part written,
   awaiting debugging and merge]

 o Add session control message flow control

 o Add NSP message flow control

 o DECnet sendpages() function