Re: [Linux-decnet-user] Porting libdnet / DECnet Kernel code

[Chrissie C. <chr...@go...>]

Philipp Schafft wrote:
> flum,
> 
> I'm a very happy user of GNU/Linux and the DECnet for Linux packet. But
> there is still a big problem with DECnet support here at my network: we
> only have the VMS,... and the Linux support for it. There is no support
> on NetBSD, OpenBSD, $STRAGE_SYSTEMS_WITH_ONLY_A_FEW_USERS.
> 
> This is why I as about porting it to those systems as well.
> 
> I think we should start to port libdnet's system independend parts, or
> the ones that should be... This includes the node and object handling,
> basic converting calls and a lot basic things.
> 
> Then we could write a dnet_conn() (and others) connecting to an daemon
> acting as proxy. This daemon may be a proxy like my socks4d (DECnet
> enabled SOCKS4) or doing DECnet in userland via libpcap or the like.
> 
> This would enable us to port the support to new systems very quickly. As
> it does not require to be in the kernel.
> 
> Later support in the kernel could be added and the only thing needed to
> change within the lib is to disable the emulation support or change
> default mode to native (kernel support) mode.
> 
> 
> Is anybody intrested in starting such a project with me? Any comments or
> suggestions?
> 
>

It sounds like an interesting project, sadly I have neither the time how
the hardware to do much coding but I'll try to help where I can if it
gets going.

Be warned, this is a BIG project! DECnet is not a small protocol to
implement (LAT supposedly is and it took me AGES to implement it in
userland using pcap!)

The other thing I'll mention is that just wrapping dnet_conn will not be
enough to catch all the programs. In fact none of mine use it! All the
clients use connect() and, of course, the daemons use listen() and
accept(). There are also several setsockopt calls that are needed to set
the connecting username and account information, as well as other
application-specific things which will be hard to emulate via a daemon.

It's all possible of course, but I suspect you will need to provide more
than just a normal link library. It will probably have to be an
LD_PRELOAD library that hooks things like connect/accept/setsockopt and
all those sorts of calls.

Have fun ;-)

Chrissie