/*
 * program for bundling channels
 * Copyright (C) 1997-2000 SpellCaster Telecommunications Inc.
 * $Id: bundle.c,v 1.1 2004/03/11 03:59:32 bcrl Exp $
 * Released under the GNU Public License. See LICENSE file for details.
 */

#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>

#include "aps_if.h"

#define CHECK_INTERVAL	5	/* in seconds, yep. */

int main ( int argc, char *argv[] )
{
	fd_set rfds;
	char buf[4096];
	struct timeval tv, uniq;
	int fd = -1, len, num;
	int bundled = 0;
	int last_sent = 0;
	int timeouts = 0;
	int good = 0;
	int ints[2];
	int iface;

	struct echodata {
		unsigned short	proto;
		struct timeval	uniq;
		struct timeval	tv;
		int		seq;
		int		reply;
	} echosent, echorecv;

	if (argc < 3) {
		fprintf(stderr, "Usage: %s <interface number> <device> <optional phone number>...\n", argv[0]);
		exit(1);
	}

	iface = atoi(argv[1]);

	gettimeofday(&uniq, NULL);

	fd = open(argv[2], O_RDWR | O_NONBLOCK);
	if (-1 == fd) {
		fprintf(stderr, "Error opening %s: %s\n", argv[2], strerror(errno));
		exit(1);
	}
	if (0 != ioctl(fd, BIOCCREATEBUNDLE, &iface) && EEXIST != errno) {
		perror("create bundle");
		exit(1);
	}

	ints[0] = 0;
	ints[1] = BF_PPP | BF_ACFC | BF_PFC | BF_PASS_IP;
	if (0 != ioctl(fd, BIOC_SETBFL, &ints))
		perror("setbfl(0, BF_PPP|BF_PASS_IP|BF_ACFC|BF_PFC)");

	close(fd);
	fd = -1;

	tv.tv_sec = CHECK_INTERVAL;
	tv.tv_usec = 0;

	for (;;) {
		if (-1 == fd) {
			printf("Opening %s...\n", argv[2]);
			fd = open(argv[2], O_RDWR | (argc > 3 ? O_NONBLOCK : 0));
			if (-1 == fd)
				fprintf(stderr, "Error opening %s: %s\n", argv[2], strerror(errno));

			if (argc > 3) {
				int fl = fcntl(fd, F_GETFL, 0);
				fl &= ~O_NONBLOCK;
				fcntl(fd, F_SETFL, fl);

				fprintf(stderr, "dialing...");
				fflush(stderr);
				if (ioctl(fd, BIOCDIAL, argv[3]) < 0) {
					perror("ioctl: dial");
					close(fd);
					fd = -1;
				} else
					fprintf(stderr, "connected.\n");
			}

			if (0 != ioctl(fd, BIOC_SETCFL, BF_PPP | BF_ACFC | BF_PFC | BF_PASS_IP))
				perror("setcfl(whatever)");
		}

		FD_ZERO(&rfds);
		if (-1 != fd)
			FD_SET(fd, &rfds);
		num = select(fd+1, &rfds, NULL, NULL, &tv);
fprintf(stderr, "select=%d\n", num);
		if (num < 0) {
			perror("select");
			continue;
		}
		if (-1 == fd)
			continue;

		if (!num) {	/* timeout */
			if (++timeouts > 2) {
				printf("timeout...\n");
leave:
				if (bundled) {
					if (0 != ioctl(fd, BIOCLEAVEBUNDLE, iface))
						perror("leave bundle");
					bundled = 0;
					printf("Dropped channel %s.\n", argv[2]);
				}
			}
send:
			tv.tv_sec = CHECK_INTERVAL;
			tv.tv_usec = 0;

			echosent.proto = 0xc090;
			gettimeofday(&echosent.tv, NULL);
			echosent.seq = ++last_sent;
			echosent.reply = 0;
			memcpy(&echosent.uniq, &uniq, sizeof(uniq));
fprintf(stderr, "echoreq\n");
			len = write(fd, &echosent, sizeof(echorecv));
			if (-1 == len && EPIPE == errno)
				goto close;
			if (-1 == len)
				perror("write");
			else if (sizeof(echorecv) != len)
				printf("short write (%d vs %d)\n", len, (int)sizeof(echorecv));
		} else {
			len = read(fd, buf, sizeof(buf));
fprintf(stderr, "read=%d\n", len);
			if (len < 0) {
				perror("read");
			} else if (!len) {
close:
				good = 0;
				timeouts = 0;
				printf("Closing %s...\n", argv[2]);
				ioctl(fd, BIOCLEAVEBUNDLE, 0);
				bundled = 0;
				if (bundled)
					printf("Dropped channel %s.\n", argv[2]);
				close(fd);
				fd = -1;
			} else if (len == sizeof(echorecv)) {
				memcpy(&echorecv, buf, sizeof(echorecv));
				if (echorecv.reply) {
					echorecv.reply = 0;
					if (!memcmp(&echorecv, &echosent, sizeof(echorecv))) {
						timeouts = 0;
						if (++good > 2 && !bundled) {
							if (0 != ioctl(fd, BIOCJOINBUNDLE, iface))
								perror("join bundle");
							else
								bundled = 1;
							printf("Added channel %s.\n", argv[2]);
						}
						if (!bundled)
							goto send;
					} else {
fprintf(stderr, "recvd different\n");
					}
				} else if (memcmp(&echorecv.uniq, &uniq, sizeof(uniq))) {
fprintf(stderr, "echoreply\n");
					echorecv.reply = 1;
					len = write(fd, &echorecv, sizeof(echorecv));
					if (-1 == len && EPIPE == errno)
						goto close;
					if (-1 == len)
						perror("write");
					else if (sizeof(echorecv) != len)
						printf("short write (%d vs %d)\n", len, (int)sizeof(echorecv));
				} else {
fprintf(stderr, "Loopback detected.\n");
					goto leave;
				}
			} else
				printf("wrong size packet received (%d instead of %d)\n", len, (int)sizeof(echorecv));
		}
	}

	return 0;
}