channel.c

/* horst - Highly Optimized Radio Scanning Tool
 *
 * Copyright (C) 2005-2014 Bruno Randolf (br1@einfach.org)
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <stdlib.h>

#include "main.h"
#include "util.h"
#include "wext.h"
#include "channel.h"


static struct chan_freq channels[MAX_CHANNELS];


#if defined(__APPLE__)

int
channel_change(__attribute__((unused)) int idx)
{
	return 0;
}

int
channel_auto_change(void)
{
	return 0;
}

int
channel_get_current_chan() {
	return -1;
}

void
channel_init(void) {
}

#else

static struct timeval last_channelchange;
extern int mon; /* monitoring socket */


long
channel_get_remaining_dwell_time(void)
{
	if (!conf.do_change_channel)
		return LONG_MAX;

	return conf.channel_time
		- the_time.tv_sec * 1000000
		- the_time.tv_usec
		+ last_channelchange.tv_sec * 1000000
		+ last_channelchange.tv_usec;
}

int
channel_change(int idx)
{
	if (wext_set_freq(mon, conf.ifname, channels[idx].freq) == 0) {
		printlog("ERROR: could not set channel %d", channels[idx].chan);
		return 0;
	}
	conf.channel_idx = idx;
	last_channelchange = the_time;
	return 1;
}


int
channel_auto_change(void)
{
	int new_idx;
	int ret = 1;
	int start_idx;

	if (channel_get_remaining_dwell_time() > 0)
		return 0; /* too early */

	if (conf.do_change_channel) {
		start_idx = new_idx = conf.channel_idx;
		do {
			new_idx = new_idx + 1;
			if (new_idx >= conf.num_channels ||
			    new_idx >= MAX_CHANNELS ||
			    (conf.channel_max &&
			     channel_get_chan_from_idx(new_idx) > conf.channel_max))
				new_idx = 0;

			ret = channel_change(new_idx);

		/* try setting different channels in case we get errors only
		 * on some channels (e.g. ipw2200 reports channel 14 but cannot
		 * be set to use it). stop if we tried all channels */
		} while (ret != 1 && new_idx != start_idx);
	}

	return ret;
}


int
channel_get_current_chan() {
	return channel_get_chan_from_idx(conf.channel_idx);
}


static int
get_current_wext_channel_idx(int mon)
{
	int freq, ch;

	/* get current channel &  map to our channel array */
	freq = wext_get_freq(mon, conf.ifname);
	if (freq == 0)
		return -1;

	ch = channel_find_index_from_freq(freq);

	DEBUG("***%d\n", ch);
	return ch;
}


void
channel_init(void) {
	/* get available channels */
	conf.num_channels = wext_get_channels(mon, conf.ifname, channels);
	conf.channel_idx = get_current_wext_channel_idx(mon);
	if (conf.channel_num_initial > 0)
	    channel_change(channel_find_index_from_chan(conf.channel_num_initial));
	else
	    conf.channel_num_initial = channel_get_chan_from_idx(conf.channel_idx);
	conf.channel_initialized = 1;
}


#endif


int
channel_find_index_from_chan(int c)
{
	int i = -1;
	for (i = 0; i < conf.num_channels && i < MAX_CHANNELS; i++)
		if (channels[i].chan == c)
			return i;
	return -1;
}


int
channel_find_index_from_freq(int f)
{
	int i = -1;
	for (i = 0; i < conf.num_channels && i < MAX_CHANNELS; i++)
		if (channels[i].freq == f)
			return i;
	return -1;
}


int
channel_get_chan_from_idx(int i) {
	if (i >= 0 && i < conf.num_channels && i < MAX_CHANNELS)
		return channels[i].chan;
	else
		return -1;
}


struct chan_freq*
channel_get_struct(int i) {
	if (i < conf.num_channels && i < MAX_CHANNELS)
		return &channels[i];
	return NULL;
}


void
channel_set(int i, int chan, int freq) {
	if (i < conf.num_channels && i < MAX_CHANNELS) {
		channels[i].chan = chan;
		channels[i].freq = freq;
	}
}