send data to serial port from kernel code

[Jerry Toung]

Good afternoon list,
I am looking for a way to write data to the serial interface (/dev/cuaa0) from 
a kernel module and also read /dev/ttyd0 still from that same kernel module.
Any pointers to doing that will be great.

I want on exchange IP traffic from FreeBSD to another host with different OS 
via serial cable (null modem). So instead of making a call the NIC driver, I 
want to use the serial port as may physical layer.
Any other ideas for doing this is welcome as well.

I know the basics of serial programming from a regular C application:

#include <termios.h>

fd = open("/dev/cuaa0", O_RDWR|O_NDELAY)
tcsetattr and tcgetattr
etc etc.


but that's not what I am looking for.

Thank you.
Jerry