net.c

wifi 无线网络路由协议OLSR linux下C代码

/*
 * The olsr.org Optimized Link-State Routing daemon(olsrd)
 * Copyright (c) 2004, Andreas T鴑nesen([e-mail])
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 *
 * * Redistributions of source code must retain the above copyright 
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright 
 *   notice, this list of conditions and the following disclaimer in 
 *   the documentation and/or other materials provided with the 
 *   distribution.
 * * Neither the name of olsr.org, olsrd nor the names of its 
 *   contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Visit http://www.olsr.org for more information.
 *
 * If you find this software useful feel free to make a donation
 * to the project. For more information see the website or contact
 * the copyright holders.
 *
 * $Id: net.c,v 1.34 2007/04/25 22:08:18 bernd67 Exp $
 */


/*
 * Linux spesific code
 */

#include "net.h"
#include "../defs.h"
#include "../net_os.h"
#include "../parser.h"


/*
 *Wireless definitions for ioctl calls
 *(from linux/wireless.h)
 */
#define SIOCGIWNAME	0x8B01		/* get name == wireless protocol */
#define SIOCGIWRATE	0x8B21		/* get default bit rate (bps) */

/* The original state of the IP forwarding proc entry */
static char orig_fwd_state;
static char orig_global_redirect_state;

/**
 *Bind a socket to a device
 *
 *@param sock the socket to bind
 *@param dev_name name of the device
 *
 *@return negative if error
 */

int
bind_socket_to_device(int sock, char *dev_name)
{
  /*
   *Bind to device using the SO_BINDTODEVICE flag
   */
  OLSR_PRINTF(3, "Binding socket %d to device %s\n", sock, dev_name);
  return setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, dev_name, strlen(dev_name)+1);
}


/**
 *Enable IP forwarding.
 *Just writing "1" to the /proc/sys/net/ipv4/ip_forward
 *if using IPv4 or /proc/sys/net/ipv6/conf/all/forwarding
 *if using IPv6.
 *Could probably drop the check for
 *"0" here and write "1" anyways.
 *
 *@param version IP version.
 *
 *@return 1 on sucess 0 on failiure
 */ 
int
enable_ip_forwarding(int version)
{
  FILE *proc_fwd;
  const char * const procfile = version == AF_INET
      ? "/proc/sys/net/ipv4/ip_forward"
      : "/proc/sys/net/ipv6/conf/all/forwarding";

  if ((proc_fwd=fopen(procfile, "r"))==NULL)
    {
      /* IPv4 */
      if(version == AF_INET)
	fprintf(stderr, "WARNING! Could not open the %s file to check/enable IP forwarding!\nAre you using the procfile filesystem?\nDoes your system support IPv4?\nI will continue(in 3 sec) - but you should mannually ensure that IP forwarding is enabeled!\n\n", procfile);
      /* IPv6 */
      else
	fprintf(stderr, "WARNING! Could not open the %s file to check/enable IP forwarding!\nAre you using the procfile filesystem?\nDoes your system support IPv6?\nI will continue(in 3 sec) - but you should mannually ensure that IP forwarding is enabeled!\n\n", procfile);
      
      sleep(3);
      return 0;
    }
  
  orig_fwd_state = fgetc(proc_fwd);
  fclose(proc_fwd);
  if(orig_fwd_state == '1')
    {
      OLSR_PRINTF(3, "\nIP forwarding is enabled on this system\n");
    }
  else
    {
      if ((proc_fwd=fopen(procfile, "w"))==NULL)
        {
          fprintf(stderr, "Could not open %s for writing!\n", procfile);
          fprintf(stderr, "I will continue(in 3 sec) - but you should mannually ensure that IP forwarding is enabeled!\n\n");
          sleep(3);
          return 0;
        }
      else
        {
          syslog(LOG_INFO, "Writing \"1\" to %s\n", procfile);
          fputs("1", proc_fwd);
        }
      fclose(proc_fwd);
    }
  return 1;      
}

int
disable_redirects_global(int version)
{
  FILE *proc_redirect;
  const char * const procfile = "/proc/sys/net/ipv4/conf/all/send_redirects";

  if(version == AF_INET6)
    return -1;

  if((proc_redirect = fopen(procfile, "r")) == NULL)
    {
      fprintf(stderr, "WARNING! Could not open the %s file to check/disable ICMP redirects!\nAre you using the procfile filesystem?\nDoes your system support IPv4?\nI will continue(in 3 sec) - but you should mannually ensure that ICMP redirects are disabled!\n\n", procfile);
      
      sleep(3);
      return -1;
    }
  orig_global_redirect_state = fgetc(proc_redirect);
  fclose(proc_redirect);

  if(orig_global_redirect_state == '0')
      return 0;

  if ((proc_redirect = fopen(procfile, "w"))==NULL)
    {
      fprintf(stderr, "Could not open %s for writing!\n", procfile);
      fprintf(stderr, "I will continue(in 3 sec) - but you should mannually ensure that ICMP redirect is disabeled!\n\n");
      sleep(3);
      return 0;
    }
  syslog(LOG_INFO, "Writing \"0\" to %s", procfile);
  fputs("0", proc_redirect);
  fclose(proc_redirect);  
  return 1;
}

/**
 *
 *@return 1 on sucess 0 on failiure
 */ 
int
disable_redirects(const char *if_name, struct interface *iface, int version)
{
  FILE *proc_redirect;
  char procfile[FILENAME_MAX];

  if(version == AF_INET6)
    return -1;

  /* Generate the procfile name */
  snprintf(procfile, sizeof(procfile), REDIRECT_PROC, if_name);


  if((proc_redirect = fopen(procfile, "r")) == NULL)
    {
      fprintf(stderr, "WARNING! Could not open the %s file to check/disable ICMP redirects!\nAre you using the procfile filesystem?\nDoes your system support IPv4?\nI will continue(in 3 sec) - but you should mannually ensure that ICMP redirects are disabled!\n\n", procfile);      
      sleep(3);
      return 0;
    }
  iface->nic_state.redirect = fgetc(proc_redirect);
  fclose(proc_redirect);      

  if ((proc_redirect = fopen(procfile, "w"))==NULL)
    {
      fprintf(stderr, "Could not open %s for writing!\n", procfile);
      fprintf(stderr, "I will continue(in 3 sec) - but you should mannually ensure that ICMP redirect is disabeled!\n\n");
      sleep(3);
      return 0;
    }
  syslog(LOG_INFO, "Writing \"0\" to %s", procfile);
  fputs("0", proc_redirect);
  fclose(proc_redirect);
  return 1;
}

/**
 *
 *@return 1 on sucess 0 on failiure
 */ 
int
deactivate_spoof(const char *if_name, struct interface *iface, int version)
{
  FILE *proc_spoof;
  char procfile[FILENAME_MAX];

  if(version == AF_INET6)
    return -1;

  /* Generate the procfile name */
  sprintf(procfile, SPOOF_PROC, if_name);

  if((proc_spoof = fopen(procfile, "r")) == NULL)
    {
      fprintf(stderr, "WARNING! Could not open the %s file to check/disable the IP spoof filter!\nAre you using the procfile filesystem?\nDoes your system support IPv4?\nI will continue(in 3 sec) - but you should mannually ensure that IP spoof filtering is disabled!\n\n", procfile);
      
      sleep(3);
      return 0;
    }
  iface->nic_state.spoof = fgetc(proc_spoof);
  fclose(proc_spoof);

  if ((proc_spoof = fopen(procfile, "w")) == NULL)
    {
      fprintf(stderr, "Could not open %s for writing!\n", procfile);
      fprintf(stderr, "I will continue(in 3 sec) - but you should mannually ensure that IP spoof filtering is disabeled!\n\n");
      sleep(3);
      return 0;
    }
  syslog(LOG_INFO, "Writing \"0\" to %s", procfile);
  fputs("0", proc_spoof);
  fclose(proc_spoof);
  return 1;
}

/**
 *Resets the spoof filter and ICMP redirect settings
 */
int
restore_settings(int version)
{
  struct interface *ifs;

  OLSR_PRINTF(1, "Restoring network state\n");

  /* Restore IP forwarding to "off" */
  if(orig_fwd_state == '0')
    {
      const char * const procfile = version == AF_INET
        ? "/proc/sys/net/ipv4/ip_forward"
        : "/proc/sys/net/ipv6/conf/all/forwarding";
      FILE *proc_fd;

      if ((proc_fd = fopen(procfile, "w")) == NULL)
	{
	  fprintf(stderr, "Could not open %s for writing!\nSettings not restored!\n", procfile);
	}
      else
	{
	  syslog(LOG_INFO, "Resetting %s to %c\n", procfile, orig_fwd_state);
	  fputc(orig_fwd_state, proc_fd);
	  fclose(proc_fd);
	}
    }

  /* Restore global ICMP redirect setting */
  if(orig_global_redirect_state != '0')
    {
      if(version == AF_INET)
	{
	  const char * const procfile = "/proc/sys/net/ipv4/conf/all/send_redirects";
          FILE *proc_fd;

	  if ((proc_fd = fopen(procfile, "w")) == NULL)
	    {
	      fprintf(stderr, "Could not open %s for writing!\nSettings not restored!\n", procfile);
	    }
	  else
	    {
	      syslog(LOG_INFO, "Resetting %s to %c\n", procfile, orig_global_redirect_state);
	      fputc(orig_global_redirect_state, proc_fd);
	      fclose(proc_fd);
	    }
	}
    }

  if(version == AF_INET6)
    return 0;

  for(ifs = ifnet; ifs != NULL; ifs = ifs->int_next)
    {
      char procfile[FILENAME_MAX];
      FILE *proc_fd;
      /* Discard host-emulation interfaces */
      if(ifs->is_hcif)
	continue;
      /* ICMP redirects */
      
      /* Generate the procfile name */
      snprintf(procfile, sizeof(procfile), REDIRECT_PROC, ifs->int_name);
      
      if ((proc_fd = fopen(procfile, "w")) == NULL)
	  fprintf(stderr, "Could not open %s for writing!\nSettings not restored!\n", procfile);
      else
	{
	  syslog(LOG_INFO, "Resetting %s to %c\n", procfile, ifs->nic_state.redirect);

	  fputc(ifs->nic_state.redirect, proc_fd);
	  fclose(proc_fd);
	}
      
      /* Spoof filter */
      
      /* Generate the procfile name */
      sprintf(procfile, SPOOF_PROC, ifs->int_name);
      if ((proc_fd = fopen(procfile, "w")) == NULL)
	  fprintf(stderr, "Could not open %s for writing!\nSettings not restored!\n", procfile);
      else
	{
	  syslog(LOG_INFO, "Resetting %s to %c\n", procfile, ifs->nic_state.spoof);

	  fputc(ifs->nic_state.spoof, proc_fd);
	  fclose(proc_fd);
	}
    }
  return 1;
}

/**
 *Creates a nonblocking broadcast socket.
 *@param sa sockaddr struct. Used for bind(2).
 *@return the FD of the socket or -1 on error.
 */
int
gethemusocket(struct sockaddr_in *pin)
{
  int sock, on = 1;

  OLSR_PRINTF(1, "       Connecting to switch daemon port 10150...");
  if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) 
    {
      perror("hcsocket");
      syslog(LOG_ERR, "hcsocket: %m");
      return -1;
    }

  if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) 
    {
      perror("SO_REUSEADDR failed");
      close(sock);
      return -1;
    }
  /* connect to PORT on HOST */
  if (connect(sock,(struct sockaddr *) pin, sizeof(*pin)) < 0) 
    {
      printf("FAILED\n");
      fprintf(stderr, "Error connecting %d - %s\n", errno, strerror(errno));
      printf("connection refused\n");
      close(sock);
      return -1;
    }

  printf("OK\n");

  /* Keep TCP socket blocking */  
  return sock;
}


/**
 *Creates a nonblocking broadcast socket.
 *@param sa sockaddr struct. Used for bind(2).
 *@return the FD of the socket or -1 on error.
 */
int
getsocket(struct sockaddr *sa, int bufspace, char *int_name)
{
  struct sockaddr_in *sin=(struct sockaddr_in *)sa;
  int sock, on = 1;

  if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) 
    {
      perror("socket");
      syslog(LOG_ERR, "socket: %m");
      return -1;
    }

#ifdef SO_BROADCAST
  if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &on, sizeof (on)) < 0)
    {
      perror("setsockopt");
      syslog(LOG_ERR, "setsockopt SO_BROADCAST: %m");
      close(sock);
      return -1;
    }
#endif

  if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) 
    {
      perror("SO_REUSEADDR failed");
      close(sock);
      return -1;
    }

#ifdef SO_RCVBUF
  for (on = bufspace; ; on -= 1024) 
    {
      if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, &on, sizeof (on)) == 0)
	break;
      if (on <= 8*1024) 
	{
	  perror("setsockopt");
	  syslog(LOG_ERR, "setsockopt SO_RCVBUF: %m");
	  break;
	}
    }
#endif

  /*
   * WHEN USING KERNEL 2.6 THIS MUST HAPPEN PRIOR TO THE PORT BINDING!!!!
   */

  /* Bind to device */