modememul.c

bluetooth 驱动

/*
 * modememul.c -- Simple modem emulator which handles dialup over BT 
 *
 * Copyright (C) 2000, 2001  Axis Communications AB
 *
 * Author: Mattias Agren <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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.
 *
 * Exceptionally, Axis Communications AB grants discretionary and
 * conditional permissions for additional use of the text contained
 * in the company's release of the AXIS OpenBT Stack under the
 * provisions set forth hereunder.
 *
 * Provided that, if you use the AXIS OpenBT Stack with other files,
 * that do not implement functionality as specified in the Bluetooth
 * System specification, to produce an executable, this does not by
 * itself cause the resulting executable to be covered by the GNU
 * General Public License. Your use of that executable is in no way
 * restricted on account of using the AXIS OpenBT Stack code with it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the provisions of the GNU
 * General Public License.
 *
 * $Id: modememul.c,v 1.15 2001/10/16 16:56:25 pkj Exp $
 *
 */

#include <sys/time.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <time.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <errno.h>
#include <stdarg.h>
#include <signal.h>

#include "btd.h"
#include "bt_misc.h"
#include "bt_if.h"

#define D(x) //x

#define PPPDCMD "pppd"

/* Modem emulator stuff */

#define RESTART 0
#define START_PPP 1

#define PPP_FLAGSEQUENCE 0x7e
#define PPP_CONTROL_ESCAPE 0x7d
#define PPP_CONF_REQ 0x1
#define PPP_TERM_REQ 0x5
#define PROT_LCP 0xc021

int modem_emulator(int bt_fd);
int parse_modem_data(int bt_fd, char *data, int len);


/* add sig handler which traps SIGHUP */

void
sighandler(int sig)
{
  D(syslog(LOG_INFO, "Got signal %d", sig));
  if ((sig == SIGQUIT) || (sig == SIGTERM || (sig == SIGHUP)))
  {
    D(syslog(LOG_INFO, "Modem emulator exiting"));
    exit(0);
  }
}

void
init_sighandler(void)
{
  struct sigaction act;

  D(syslog(LOG_INFO, "Initiating signal handler"));
  act.sa_handler = sighandler;
  sigemptyset(&act.sa_mask);
  act.sa_flags = 0;
  sigaction(SIGHUP, &act, 0);
  sigaction(SIGQUIT, &act, 0);
  sigaction(SIGTERM, &act, 0);
}

int
main(int argc, char **argv)
{
  int btfd;
  char *speedstr;
  int done = 0;
  int line = -1;
  
  setsid(); /* become session leader (to catch SIGHUPS) */  
  init_sighandler();

  speedstr = argv[2];
  if (sscanf(argv[1], "/dev/ttyBT%d", &line) != 1)
  {
    fprintf(stderr, "Invalid arguments to modememulator\n");
    exit(1);
  }    

  while (done != START_PPP)
  {
    syslog(LOG_INFO, "Starting modem emulator on %s", argv[1]);

    if (!bt_isconnected(-1, line))
    {
      D(syslog(LOG_INFO, "No BT connection, stopping modememulator"));
      exit(0);
    }

    if ((btfd = open(argv[1], O_RDWR, 0)) < 0)
    {
      perror("open");
      exit(1);
    }

    /* not necessary for BT devices... */
    fd_setup(btfd, speedstr, USE_NO_FLOW);
    done = modem_emulator(btfd);
    close(btfd);
    D(syslog(LOG_INFO, "Closing %s", argv[1]));
  }

  /* replace first arg with pppd instead of modem emulator 
     rest of arguments are the same */

  argv[0] = PPPDCMD;

  execvp(PPPDCMD, argv /*pppd_options*/);
  
  fprintf(stderr, "%s: no such file or directory\n", PPPDCMD);
  exit(1);
}

int modem_emulator(int bt_fd)
{ 
  char *connect = "CONNECT\r\n";
  char *client_server = "CLIENTSERVER\r\n";
  char *ok = "OK\r\n";
  char data[128];
  int done = 0, i;
  fd_set rfd;

  D(syslog(LOG_INFO, "Modem emulator starting"));

  while (!done)
  {  
    FD_ZERO(&rfd); 
    FD_SET(bt_fd, &rfd);
    select(FD_SETSIZE, &rfd, NULL, NULL, NULL);
    
    if (FD_ISSET(bt_fd, &rfd))
    { 
      int len = read(bt_fd, &data, 128);      
      data[len] = 0;
      
      D(syslog(LOG_INFO, "Modem emulator got %d bytes", len));
      
      if (len <= 0)
	return RESTART;      

      /* Check if data is a ppp frame, if so start pppd right away */

      for (i = 0; i < len; i++)
      {
        if ((data[i] == PPP_FLAGSEQUENCE))
        {
          if ((len - i) >= 7)
          {
            unsigned short prot;
            unsigned short type;

            /* check for escaped chars */            
            if (data[i+2] == PPP_CONTROL_ESCAPE) 
            { 
              D(syslog(LOG_INFO, "Found ctrl esc"));
              prot = ((data[i+4]<<8) | (data[i+5]));
            }
            else
            {
              prot = ((data[i+3]<<8) | (data[i+4]));
            }
            
            D(syslog(LOG_INFO, "prot : %x", prot));
            
            D(print_data("ppp packet : ", data, len));
            
            if (prot == PROT_LCP)
            {
              type = (data[i+7]^0x20);
              
              if (type == PPP_TERM_REQ)
              {
                syslog(LOG_INFO, "Found PPP Terminate, restart modem emulator");
                return RESTART;
              }
              else if (type == PPP_CONF_REQ)
              {  
                syslog(LOG_INFO, "Found PPP Connect, start pppd");
                return START_PPP;
              }
              else
              {
                syslog(LOG_INFO, "Unknown PPP LCP type [%d]", type);
                return START_PPP; /* start pppd anyway */
              } 
            }
            else
            {
              syslog(LOG_INFO, "Unknown PPP prot type [%d]", prot);
              return RESTART; 
            }
          }
	}      
      }
      
      /* AT commands */

      if (!strncasecmp(data, "ATD", 3)) /* windows standard modem */
      {
	D(syslog(LOG_INFO, "Got ATD"));

	D(syslog(LOG_INFO, "Write: %s", connect));
	write(bt_fd, connect, strlen(connect));   
        syslog(LOG_INFO, "Modem connected!");
	return START_PPP;
      }
      else if (!strncasecmp(data, "CLIENT", 6)) /* windows null modem */
      {
	D(syslog(LOG_INFO, "Got CLIENT"));
	write(bt_fd, client_server, strlen(client_server));   
        syslog(LOG_INFO, "Nullmodem connected!");
	return START_PPP;
      }
      else
      {
	syslog(LOG_INFO, "Modem emulator replies OK");
	write(bt_fd, ok, strlen(ok)); 
      }
    }
  }
  return done;
}