#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>

/* this program wants to be called with 'strace -s1024 -x' so you see the data
 * betewen DAHDI and it */

const uint8_t sabme_frame_nonraw[] = { 0xFA, 0x7D, 0x7F, 0x00, 0x00 };

static int fd;
static uint8_t dummy_buf[8192];

static void dummy_read(int fd, unsigned int len)
{
	int rc;

	if (len > sizeof(dummy_buf))
		len = sizeof(dummy_buf);

	rc = read(fd, dummy_buf, len);
}

int main(int argc, char **argv)
{
	int rc;

	if (argc < 2)
		exit(2);

	fd = open(argv[1], O_RDWR|O_NONBLOCK);
	if (fd < 0) {
		perror("open");
		exit(1);
	}
	
	while (1) {
		fd_set read_fd;
		struct timeval timeout;

		FD_ZERO(&read_fd);
		FD_SET(fd, &read_fd);

		timeout.tv_sec = 1;
		timeout.tv_usec = 0;

		rc = select(fd+1, &read_fd, NULL, NULL, &timeout);
		if (rc < 0) {
			perror("Select");
			exit(1);
		} else if (rc) {
			dummy_read(fd, 16);
		} else {
			write(fd, sabme_frame_nonraw, sizeof(sabme_frame_nonraw));
		}
	}
}