[9fans] channels across machines

[Bakul Shah <bakul+plan9@bitblocks.com>]

Has anyone extended the idea of channels where the
sender/receiver are on different machines (or at least in
different processes)?  A netcat equivalent for channels!

Actual plumbing seems easy: one can add a `proxy' thread in
each process to send a message via whatever inter process
mechanism is available. One issue would be for the two sides
to identify a specific channel.  I imagine something like the
following would work.

	// on the client:
	chan = chanconnect("<host>:<port>", elemsize, nelem);

	// on the server:
	x = chanbind("<port>", elemsize, nelem);
	chan = chanaccept(x); // to allow multiple connections

Or one can build this on top of a socket or file descriptor.

Another issue is endianness (unless all processors are the
same type). Yet another issue is sending variable size
things. In a single address space you can pass a pointer +
may be a size but that trick doesn't work across process (or
machine boundaries) -- so pretty much have to add some
marshalling/unmarshalling that knows about types.

Or is there a better idea?  This certainly seems preferable
to RPC or plain byte pipes for communicating structured
values.

Thanks!

--bakul