owlps/libowlps/libowlps.c

/*
 * This file is part of the rtap localisation project.
 */


#include "owlps.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#include <string.h>
#include <time.h>
#include <signal.h>

#include <sys/ioctl.h>
#include <net/if.h>
#include <iwlib.h>

#include <assert.h>

#define DEBUG


owl_bool owl_run = TRUE ;



/* *** Miscellaneous functions *** */


/*
 * Converts a MAC address from bytes to string.
 * The string is allocated in a static buffer, and will be overwritten
 * each time this function is called.
 * This function is not thread-safe!
 */
const char* owl_mac_bytes_to_string(const uint8_t *const mac_binary)
{
  static char mac_str[OWL_ETHER_ADDR_STRLEN] ;
  owl_mac_bytes_to_string_r(mac_binary, mac_str) ;
  return mac_str ;
}


/*
 * Converts a MAC address from bytes to string.
 * 'mac_str' must be allocated by the caller.
 * This function is thread-safe.
 */
void owl_mac_bytes_to_string_r(const uint8_t *const mac_binary,
                               char mac_str[OWL_ETHER_ADDR_STRLEN])
{
  sprintf(mac_str, "%02x:%02x:%02x:%02x:%02x:%02x",
          mac_binary[0], mac_binary[1], mac_binary[2],
          mac_binary[3], mac_binary[4], mac_binary[5]) ;
}


/*
 * Compares two MAC addresses.
 * Returns TRUE if they are identical, FALSE otherwise.
 */
owl_bool owl_mac_equals(const uint8_t *const mac1,
                        const uint8_t *const mac2)
{
  int i ;
  for (i = 0 ; i < ETHER_ADDR_LEN ; ++i)
    if(mac1[i] != mac2[i])
      return FALSE ;
  return TRUE ;
}


/*
 * Converts a IEEE 802.11 frequency into a channel number.
 * Returns 0 if the frequency does not correspond to an official channel.
 */
uint_fast8_t owl_frequency_to_channel(const uint_fast16_t channel)
{
  uint_fast8_t c = 0 ; // Result

  switch (channel)
    {
    case CHANNEL_1 :
      c = 1 ;
      break ;
    case CHANNEL_2 :
      c = 2 ;
      break ;
    case CHANNEL_3 :
      c = 3 ;
      break ;
    case CHANNEL_4 :
      c = 4 ;
      break ;
    case CHANNEL_5 :
      c = 5 ;
      break ;
    case CHANNEL_6 :
      c = 6 ;
      break ;
    case CHANNEL_7 :
      c = 7 ;
      break ;
    case CHANNEL_8 :
      c = 8 ;
      break ;
    case CHANNEL_9 :
      c = 9 ;
      break ;
    case CHANNEL_10 :
      c = 10 ;
      break ;
    case CHANNEL_11 :
      c = 11 ;
      break ;
    case CHANNEL_12 :
      c = 12 ;
      break ;
    case CHANNEL_13 :
      c = 13 ;
      break ;
    case CHANNEL_14 :
      c = 14 ;
      break ;
    }

  return c ;
}



/* *** Time *** */


/*
 * Sets the owl_timestamp 'now' at the current time.
 * Returns 0 in case of success non-zero otherwise.
 */
int owl_timestamp_now(owl_timestamp *const now)
{
  int ret ;
  struct timespec now_ts ;
  if ((ret = clock_gettime(CLOCK_REALTIME, &now_ts)))
    {
      perror("Cannot get the current time") ;
      return ret ;
    }

  *now = owl_timespec_to_timestamp(now_ts) ;

  return 0 ;
}


/*
 * Returns a owl_timestamp from a struct timespec.
 */
owl_timestamp owl_timespec_to_timestamp(const struct timespec d)
{
  owl_timestamp res ;
  res.tv_sec = d.tv_sec ;
  res.tv_nsec = d.tv_nsec ;
  return res ;
}


/*
 * Returns a owl_timestamp from a struct timeval.
 */
owl_timestamp owl_timeval_to_timestamp(const struct timeval d)
{
  owl_timestamp res ;
  res.tv_sec = d.tv_sec ;
  res.tv_nsec = d.tv_usec * 1000u ;
  return res ;
}


owl_bool owl_timestamp_equals(const owl_timestamp d1,
                              const owl_timestamp d2)
{
  return d1.tv_sec == d2.tv_sec && d1.tv_nsec == d2.tv_nsec ;
}


owl_bool owl_timestamp_is_null(const owl_timestamp d)
{
  return d.tv_sec == 0 && d.tv_nsec == 0 ;
}


/*
 * Converts a owl_timestamp date value into milliseconds.
 */
uint64_t owl_timestamp_to_ms(const owl_timestamp d)
{
  return (uint64_t) d.tv_sec * 1000u + (uint64_t) d.tv_nsec / 1000000lu ;
}


/*
 * Converts a owl_timestamp date value into a printable string.
 * 'dst' must be an allocated array of at least owl_timestamp_STR_LEN
 * characters.
 */
void owl_timestamp_to_string(char *const dst, const owl_timestamp src)
{
  snprintf(dst, OWL_TIMESTAMP_STR_LEN, "%"PRIu32".%"PRIu32,
           src.tv_sec, src.tv_nsec) ;
}


/*
 * Returns the time (in milliseconds) between two dates.
 */
uint_fast32_t owl_time_elapsed_ms(const owl_timestamp d1,
                                  const owl_timestamp d2)
{
  return owl_timestamp_to_ms(owl_time_elapsed(d1, d2)) ;
}


/*
 * Returns a owl_timestamp storing the time between two dates.
 */
owl_timestamp owl_time_elapsed(const owl_timestamp d1,
                               const owl_timestamp d2)
{
  owl_timestamp elapsed ;
  elapsed.tv_sec = abs(d1.tv_sec - d2.tv_sec) ;
  elapsed.tv_nsec = abs(d1.tv_nsec - d2.tv_nsec) ;
#ifdef DEBUG
  fprintf(stderr, "time_elapsed(): %"PRIu64"ms\n",
          owl_timestamp_to_ms(elapsed)) ;
#endif
  return elapsed ;
}



/* *** Endianess *** */


/*
 * Converts a owl_timestamp from host endianess to network endianess.
 */
owl_timestamp owl_hton_timestamp(const owl_timestamp d)
{
  owl_timestamp date ;
  date.tv_sec = htonl(d.tv_sec) ;
  date.tv_nsec = htonl(d.tv_nsec) ;
  return date ;
}


/*
 * Converts a owl_timestamp from network endianess to host endianess.
 */
owl_timestamp owl_ntoh_timestamp(const owl_timestamp d)
{
  owl_timestamp date ;
  date.tv_sec = ntohl(d.tv_sec) ;
  date.tv_nsec = ntohl(d.tv_nsec) ;
  return date ;
}


/*
 * Swap bytes composing a float.
 * You probably want to use the macros owl_htonf() and owl_ntohf()
 * instead of this function.
 */
float owl_swap_float(const float f)
{
  float ret ;
  char
    *f_bytes = (char*) &f,
    *ret_bytes = (char*) &ret ;

  assert(sizeof(float) == 4) ;

  ret_bytes[0] = f_bytes[3] ;
  ret_bytes[1] = f_bytes[2] ;
  ret_bytes[2] = f_bytes[1] ;
  ret_bytes[3] = f_bytes[0] ;

  return ret ;
}



/* *** Network *** */


/*
 * Creates a UDP transmission socket and returns its descriptor.
 * Parameters:
 *  - server_address: the server IP address.
 *  - server_port: the listening port on the server.
 *  - server_description (in/out): the structure in which the server
 *    description will be saved.
 *  - client_description (in/out): the structure in which the client
 *    description will be saved.
 */
int owl_create_udp_trx_socket(const char *const server_address,
                              const uint_fast16_t server_port,
                              struct sockaddr_in *const server_description,
                              struct sockaddr_in *const client_description)
{
  int sockfd ; // Socket descriptor

  /* Create the UDP socket */
  sockfd = socket(AF_INET, SOCK_DGRAM, 0) ;
  if (sockfd < 0)
    {
      perror("UDP socket creation failed") ;
      return sockfd ;
    }

  /* Initialise the client structure */
  memset(client_description, 0, sizeof(*client_description)) ;
  client_description->sin_family = AF_INET ; // INET socket
  client_description->sin_addr.s_addr = htonl(INADDR_ANY) ;

  /* Initialise the server structure */
  memset(server_description, 0, sizeof(*server_description)) ;
  server_description->sin_family = AF_INET ; // INET socket
  // Server IP address:
  server_description->sin_addr.s_addr = inet_addr(server_address) ;
  // Listening port on the server:
  server_description->sin_port = htons(server_port) ;

  return sockfd ;
}


/*
 * Creates a UDP reception socket and returns its descriptor.
 * Parameters:
 *  - port: port on which the socket listens.
 */
int owl_create_udp_listening_socket(const uint_fast16_t port)
{
  int sockfd ; // Socket descriptor
  struct sockaddr_in server_description ; // Server structure
  int ret = 0 ; // Return value

  /* Create the UDP socket */
  sockfd = socket(AF_INET, SOCK_DGRAM, 0) ;
  if (sockfd < 0)
    {
      perror("UDP socket creation failed") ;
      return sockfd ;
    }

  /* Initialise the server structure */
  memset(&server_description, 0, sizeof(server_description)) ;
  server_description.sin_family = AF_INET ; // INET socket
  // All the connections are accepted:
  server_description.sin_addr.s_addr = htonl(INADDR_ANY) ;
  server_description.sin_port = htons(port) ; // Listening port

  /* Port reservation */
  ret = bind(sockfd, (struct sockaddr*) &server_description,
             sizeof(server_description)) ;
  if (ret < 0)
    {
      perror("Cannot bind the UDP socket") ;
      close(sockfd) ;
      return ret ;
    }

  return sockfd ;
}


/*
 * Switches the IEEE 802.11 interface 'iface' to Monitor mode.
 */
int owl_iface_mode_monitor(const char *const iface)
{
  struct iwreq wrq ;
  int sockfd = iw_sockets_open() ;

  strncpy((&wrq)->ifr_name, iface, IFNAMSIZ) ;

  if (ioctl(sockfd, SIOCGIWMODE, &wrq) == -1) // Get current mode
    {
      perror("Error reading interface mode") ;
      return ERR_READING_MODE ;
    }

  // If interface is not yet in Monitor mode
  if (wrq.u.mode != IW_MODE_MONITOR)
    {
      wrq.u.mode = IW_MODE_MONITOR ;
      if (ioctl(sockfd, SIOCSIWMODE, &wrq) == -1) // Set up Monitor mode
        {
          perror("Error setting up Monitor mode") ;
          return ERR_SETTING_MODE ;
        }
    }

  close(sockfd) ;

  return 0 ;
}


/*
 * Sets the IEEE 802.11 channel of the interface 'iface'.
 * 'channel' must be an integer between 1 and 14.
 */
int owl_iface_set_channel(const char *const iface,
                          const uint_fast8_t channel)
{
  struct iwreq wrq ;
  int sockfd = iw_sockets_open() ;

  strncpy((&wrq)->ifr_name, iface, IFNAMSIZ) ;
  iw_float2freq(channel, &(wrq.u.freq)) ;
  wrq.u.freq.flags = IW_FREQ_FIXED ;

  if (ioctl(sockfd, SIOCSIWFREQ, &wrq) == -1)
    {
      perror("Error setting the Wi-Fi channel") ;
      return ERR_SETTING_CHANNEL ;
    }

  close(sockfd) ;

  return 0 ;
}


/*
 * Switches alternatively the Wi-Fi channel of the IEEE 802.11 interface
 * 'iface' to 4 or 11.
 */
int owl_iface_channel_hop(const char *const iface)
{
  uint_fast16_t channel ;
  struct iwreq wrq ;
  int sockfd = iw_sockets_open() ;

  strncpy((&wrq)->ifr_name, iface, IFNAMSIZ) ;

  if (ioctl(sockfd, SIOCGIWFREQ, &wrq) == -1)
    {
      perror("Error reading the frequency") ;
      return ERR_READING_CHANNEL ;
    }
  // The following is not very clean: we should use iw_freq2float(),
  // iw_freq_to_channel() & friends, cf. /usr/include/{iwlib.h,wireless.h}.
  channel = wrq.u.freq.m / 100000 ;

  if (channel > 1000) // If the value is in Hz, we convert it to a
    channel = owl_frequency_to_channel(channel) ; // channel number
  // (with our own function, still not very clean).

  close(sockfd) ;

  /* Switch the canal */
  if (channel == 4) // If channel is 4
    return owl_iface_set_channel(iface, 11) ; // switch to 11 ;
  else
    return owl_iface_set_channel(iface, 4) ; // else, set it to 4.
}



/* *** Signals *** */


/*
 * Generic signal handler for SIGINT.
 */
void owl_sigint_handler(const int num)
{
  if (num != SIGINT)
    {
      fprintf(stderr, "Error! The SIGINT handler was called but the"
              " signal is not SIGINT.\n") ;
      exit(ERR_BAD_SIGNAL) ;
    }

  owl_run = FALSE ;

#ifdef DEBUG
  fprintf(stderr, "\nSignal received: end.\n");
#endif // DEBUG
  fflush(NULL) ;
}


/*
 * Generic signal handler for SIGTERM.
 */
void owl_sigterm_handler(const int num)
{
  if (num != SIGTERM)
    {
      fprintf(stderr, "Error! The SIGTERM handler was called but the"
              " signal is not SIGTERM.\n") ;
      exit(ERR_BAD_SIGNAL) ;
    }

  owl_sigint_handler(SIGINT) ;
}



/* *** Thread-related functions *** */


/*
 * Closes the file descriptor 'fd'.
 * 'fd' must be passed as an int pointer (int*).
 */
void owl_close_fd(void *const fd)
{
  if (fd == NULL)
    return ;

  const int *const file_desc = fd ;
  if (close(*file_desc) != 0)
    perror("Error closing file descriptor") ;
#ifdef DEBUG
  else
    fprintf(stderr, "File descriptor %d closed successfully.\n",
            *file_desc) ;
#endif // DEBUG
}


/*
 * Closes the stream 'file'.
 * 'file' must be passed as a pointer on a pointer of FILE (FILE**).
 * If *file either stdout, stderr or stdin, it will not be closed.
 */
void owl_close_file(void *const file)
{
  if (file == NULL)
    return ;

  FILE **stream = file ;
  if (*stream == stdout || *stream == stderr || *stream == stdin)
    return ;

  if (fclose(*stream) != 0)
    perror("Error closing stream") ;
#ifdef DEBUG
  else
    fprintf(stderr, "Stream closed successfully.\n") ;
#endif // DEBUG
}