text: /*
   * Copyright (c) 2012 Tristan Le Guern <tleguern@bouledef.eu>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * Copyright (c) 2016 Mahdi Mokhtari <mokhi64@gmail.com>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. 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.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #ifdef __sun
  #define BSD_COMP
  #define TUNSDEBUG _IOW('t', 90, int)
  #endif
  
  #include <sys/ioctl.h>
  #include <sys/socket.h>
  #include <sys/types.h>
  
  #include <arpa/inet.h>
  #include <netinet/in.h>
  #if defined(Linux)
  #include <linux/if_tun.h>
  #include <linux/if_ether.h>
  #else
  
  #include <net/if.h>
  #if defined(DragonFly)
  #include <net/tun/if_tun.h>
  #elif defined(ANDROID)
  #include <linux/if_tun.h>
  #elif !defined(Darwin)
  #include <net/if_tun.h>
  #endif
  #include <netinet/if_ether.h>
  #include <netinet/in.h>
  #endif
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  #include <unistd.h>
  
  #include <tuntap.h>
  
  int
  tuntap_start(struct device *dev, int mode, int tun)
  {
    int sock;
    int fd;
  
    fd = sock = -1;
  
    /* Don't re-initialise a previously started device */
    if(dev->tun_fd != -1)
    {
      tuntap_log(TUNTAP_LOG_ERR, "Device is already started");
      return -1;
    }
  
    sock = socket(AF_INET, SOCK_DGRAM, 0);
    if(sock == -1)
    {
      goto clean;
    }
    dev->ctrl_sock = sock;
  
    if(mode & TUNTAP_MODE_PERSIST && tun == TUNTAP_ID_ANY)
    {
      goto clean; /* XXX: Explain why */
    }
  
    fd = tuntap_sys_start(dev, mode, tun);
    if(fd == -1)
    {
      goto clean;
    }
  
    dev->tun_fd = fd;
    tuntap_set_debug(dev, 0);
    return 0;
  
  clean:
    if(fd != -1)
    {
      (void)close(fd);
    }
    if(sock != -1)
    {
      (void)close(sock);
    }
    return -1;
  }
  
  void
  tuntap_release(struct device *dev)
  {
    (void)close(dev->tun_fd);
    (void)close(dev->ctrl_sock);
    free(dev);
  }
  
  int
  tuntap_set_descr(struct device *dev, const char *descr)
  {
    size_t len;
  
    if(descr == NULL)
    {
      tuntap_log(TUNTAP_LOG_ERR, "Invalid parameter 'descr'");
      return -1;
    }
  
    len = strlen(descr);
    if(len > IF_DESCRSIZE)
    {
      /* The value will be troncated */
      tuntap_log(TUNTAP_LOG_WARN, "Parameter 'descr' is too long");
    }
  
    if(tuntap_sys_set_descr(dev, descr, len) == -1)
    {
      return -1;
    }
    return 0;
  }
  
  int
  tuntap_set_ifname(struct device *dev, const char *ifname)
  {
    size_t len;
  
    if(ifname == NULL)
    {
      tuntap_log(TUNTAP_LOG_ERR, "Invalid parameter 'ifname'");
      return -1;
    }
  
    len = strlen(ifname);
    if(len > IF_NAMESIZE)
    {
      tuntap_log(TUNTAP_LOG_ERR, "Parameter 'ifname' is too long");
      return -1;
    }
  
    if(tuntap_sys_set_ifname(dev, ifname, len) == -1)
    {
      return -1;
    }
  
    (void)memset(dev->if_name, 0, IF_NAMESIZE);
    (void)strncpy(dev->if_name, ifname, len);
    return 0;
  }
  
  int
  tuntap_up(struct device *dev)
  {
    struct ifreq ifr;
  
    (void)memset(&ifr, '\0', sizeof ifr);
    (void)memcpy(ifr.ifr_name, dev->if_name, sizeof dev->if_name);
    ifr.ifr_flags = (short int)dev->flags;
    ifr.ifr_flags |= IFF_UP;
  
    if(ioctl(dev->ctrl_sock, SIOCSIFFLAGS, &ifr) == -1)
    {
      return -1;
    }
  
    dev->flags = ifr.ifr_flags;
    return 0;
  }
  
  int
  tuntap_down(struct device *dev)
  {
    struct ifreq ifr;
  
    (void)memset(&ifr, '\0', sizeof ifr);
    (void)memcpy(ifr.ifr_name, dev->if_name, sizeof dev->if_name);
    ifr.ifr_flags = (short)dev->flags;
    ifr.ifr_flags &= ~IFF_UP;
  
    if(ioctl(dev->ctrl_sock, SIOCSIFFLAGS, &ifr) == -1)
    {
      return -1;
    }
  
    dev->flags = ifr.ifr_flags;
    return 0;
  }
  
  int
  tuntap_get_mtu(struct device *dev)
  {
    struct ifreq ifr;
  
    /* Only accept started device */
    if(dev->tun_fd == -1)
    {
      tuntap_log(TUNTAP_LOG_NOTICE, "Device is not started");
      return 0;
    }
  
    (void)memset(&ifr, '\0', sizeof ifr);
    (void)memcpy(ifr.ifr_name, dev->if_name, sizeof dev->if_name);
  
    if(ioctl(dev->ctrl_sock, SIOCGIFMTU, &ifr) == -1)
    {
      tuntap_log(TUNTAP_LOG_ERR, "Can't get MTU");
      return -1;
    }
    return ifr.ifr_mtu;
  }
  
  int
  tuntap_set_mtu(struct device *dev, int mtu)
  {
    struct ifreq ifr;
  
    /* Only accept started device */
    if(dev->tun_fd == -1)
    {
      tuntap_log(TUNTAP_LOG_NOTICE, "Device is not started");
      return 0;
    }
  
    (void)memset(&ifr, '\0', sizeof ifr);
    (void)memcpy(ifr.ifr_name, dev->if_name, sizeof dev->if_name);
    ifr.ifr_mtu = mtu;
  
    if(ioctl(dev->ctrl_sock, SIOCSIFMTU, &ifr) == -1)
    {
      tuntap_log(TUNTAP_LOG_ERR, "Can't set MTU");
      return -1;
    }
    return 0;
  }
  
  int
  tuntap_read(struct device *dev, void *buf, size_t size)
  {
    int n;
  
    /* Only accept started device */
    if(dev->tun_fd == -1)
    {
      tuntap_log(TUNTAP_LOG_NOTICE, "Device is not started");
      return 0;
    }
  
    n = read(dev->tun_fd, buf, size);
    if(n == -1)
    {
      tuntap_log(TUNTAP_LOG_WARN, "Can't to read from device");
      return -1;
    }
    return n;
  }
  
  int
  tuntap_write(struct device *dev, void *buf, size_t size)
  {
    int n;
  
    /* Only accept started device */
    if(dev->tun_fd == -1)
    {
      tuntap_log(TUNTAP_LOG_NOTICE, "Device is not started");
      return 0;
    }
  
    n = write(dev->tun_fd, buf, size);
    if(n == -1)
    {
      tuntap_log(TUNTAP_LOG_WARN, "Can't write to device");
      return -1;
    }
    return n;
  }
  
  int
  tuntap_get_readable(struct device *dev)
  {
    int n;
  
    n = 0;
    if(ioctl(dev->tun_fd, FIONREAD, &n) == -1)
    {
      tuntap_log(TUNTAP_LOG_INFO,
                 "Your system does not support"
                 " FIONREAD, fallback to MTU");
      return tuntap_get_mtu(dev);
    }
    return n;
  }
  
  int
  tuntap_set_nonblocking(struct device *dev, int set)
  {
    if(ioctl(dev->tun_fd, FIONBIO, &set) == -1)
    {
      switch(set)
      {
        case 0:
          tuntap_log(TUNTAP_LOG_ERR, "Can't unset nonblocking");
          break;
        case 1:
          tuntap_log(TUNTAP_LOG_ERR, "Can't set nonblocking");
          break;
        default:
          tuntap_log(TUNTAP_LOG_ERR, "Invalid parameter 'set'");
      }
      return -1;
    }
    return 0;
  }
  
  int
  tuntap_set_debug(struct device *dev, int set)
  {
    /* Only accept started device */
    if(dev->tun_fd == -1)
    {
      tuntap_log(TUNTAP_LOG_NOTICE, "Device is not started");
      return 0;
    }
  
  #if !defined Darwin
    if(ioctl(dev->tun_fd, TUNSDEBUG, &set) == -1)
    {
      switch(set)
      {
        case 0:
          tuntap_log(TUNTAP_LOG_WARN, "Can't unset debug");
          break;
        case 1:
          tuntap_log(TUNTAP_LOG_WARN, "Can't set debug");
          break;
        default:
          tuntap_log(TUNTAP_LOG_ERR, "Invalid parameter 'set'");
      }
      return -1;
    }
    return 0;
  #else
    (void)set;
    tuntap_log(TUNTAP_LOG_NOTICE,
               "Your system does not support tuntap_set_debug()");
    return -1;
  #endif
  }
  