[Linux-decnet-user] DECnet kernel update

[Steven W. <st...@gw...>]

Hi,

Its a little while since I last updated everyone on what I'm working on for
Linux DECnet at the moment. I've got a new work-in-progress patch which is
available here: 

http://www.chygwyn.com/~steve/kpatch/decnet/decnet-2.5.64-routing2.diff

Its feature enhancements for 2.5 mostly - preparing the way for us to add
zero-copy (needs a tidy around sendmsg/recvmsg first, which is done in this
patch) and also starts to tidy up the routing code. This is an area which
has been neglected for too long and I'd really like to get it fixed up.

Part of the plan is to make it as similar to the IPv4 routing code as possible
in order to take advantage of the work in optimising the code which has already
gone on in the IPv4 stack and also so that people working on the IPv4 code
will feel at home looking at the DECnet routing code to encourage them to
help us along. This work-in-progress patch adds support for DECnet into
flow.h and uses the struct flowi as a routing key, some further adjustments
need to be done before the patch is submitted, in particular dealing with
the "scope" of routes.

In the future, as well as adding zero-copy support, the other major work
item on my agenda is to change the way that the routing code works so that
the current default behaviour will be maintained by the automatic addition
of route entries into the routing tables. At this stage all routing decisions
will be made by lookups in the routing table, unlike the current situation
where many of the default rules described in the DECnet documents are
implemented as special case rules built into the code and the routing tables
are an extra add-on.

This seems to make more sense to me since it will clean up the code and also
mean that in special cases where people don't wish to (for whatever reason)
abide by the default rules, they'll find the system more flexible.

Please feel free to send me any comments, questions or suggestions,

Steve.

P.S. An article on the Linux DECnet project written by myself and Patrick
Caulfield is in issue 27 of "Linux User" but only the news stand version I 
gather. A similar article will be appearing in "Ping" in the near future.