/*
  dund - Bluetooth LAN/DUN daemon for BlueZ
  Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
	
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2, as
  published by the Free Software Foundation.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
*/

/*
 * $Id$
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <syslog.h>
#include <setjmp.h>
#include <string.h>

#include "lib.h"

#define MS_PPP      2
#define MS_SUCCESS  1
#define MS_FAILED  -1
#define MS_TIMEOUT -2

static sigjmp_buf jmp;
static int        retry;
static int        timeout;

static void sig_alarm(int sig)
{
	siglongjmp(jmp, MS_TIMEOUT);
}

static int w4_str(int fd, char *str)
{
	char buf[40];
	int  r, len = 0;
	
	while (1) {
		r = read(fd, buf + len, sizeof(buf) - len - 1);
		if (r < 0) {
			if (errno == EINTR || errno == EAGAIN)
				continue;
			break;
		}
		if (!r)
			break;

		len += r;

		if (len < strlen(str))
			continue;
		buf[len] = 0;

		if (strstr(buf, str))
			return MS_SUCCESS;

		/* Detect PPP */
		if (strchr(buf, '~'))
			return MS_PPP;
	}
	return MS_FAILED;
}

static int ms_server(int fd)
{
	switch (w4_str(fd, "CLIENT")) {
	case MS_SUCCESS:
		write_n(fd, "CLIENTSERVER", 12);
	case MS_PPP:
		return MS_SUCCESS;
	default:	
		return MS_FAILED;
	}
}

static int ms_client(int fd)
{
	write_n(fd, "CLIENT", 6);
	return w4_str(fd, "CLIENTSERVER");
}

int ms_dun(int fd, int server, int timeo)
{
	sig_t osig;

	retry    = 4;
	timeout  = timeo;

	if (!server)
		timeout /= retry;

	osig = signal(SIGALRM, sig_alarm);

	while (1) {
		int r = sigsetjmp(jmp, 1);
		if (r) {
			if (r == MS_TIMEOUT && !server && --retry)
				continue;

			alarm(0);
			signal(SIGALRM, osig);
		
			switch (r) {
			case MS_SUCCESS:
			case MS_PPP:
				errno = 0;
				return 0;

			case MS_FAILED:
				errno = EPROTO;
				break;

			case MS_TIMEOUT:
				errno = ETIMEDOUT;
				break;
			}
			return -1;
		}

		alarm(timeout);
		
		if (server)
			r = ms_server(fd);
		else
			r = ms_client(fd);

		siglongjmp(jmp, r);
	}
}