Philip Christian wrote:
> In fact I have manually forced an address into this structure
> inside the rclnp_output function and recompiled the kernel, and a
> packet is then actually transmitted.

Seems like the address isn't properly copied to ISO-specific structures
for some reason.

> I cannot figure out what the kernel does when send() or sendto() are executed.
> There are various tables of system calls in places like /sys/syscall.h
> but I can't get from there to the actual code.

send() is now userland wrapper around sendto(2) syscall. Look
in kernel, in src/sys/kern/uipc_syscalls.c:sys_sendto() for actual
implementation.
My guess there is some #ifdef ISO missing somewhere in kernel,
somewhere along similar #ifdef INET etc.

Jaromir
-- 
Jaromir Dolecek <jdolecek@NetBSD.org>            http://www.NetBSD.org/
-=- We should be mindful of the potential goal, but as the tantric    -=-
-=- Buddhist masters say, ``You may notice during meditation that you -=-
-=- sometimes levitate or glow.   Do not let this distract you.''     -=-