src/p2p/p2p_utils.c - third_party/hostap - Git at Google

 /*
  * P2P - generic helper functions
  * Copyright (c) 2009, Atheros Communications
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
  */

 #include "includes.h"

 #include "common.h"
 #include "common/defs.h"
 #include "common/ieee802_11_common.h"
 #include "p2p_i.h"


 /**
  * p2p_random - Generate random string for SSID and passphrase
  * @buf: Buffer for returning the result
  * @len: Number of octets to write to the buffer
  * Returns: 0 on success, -1 on failure
  *
  * This function generates a random string using the following character set:
  * 'A'-'Z', 'a'-'z', '0'-'9'.
  */
 int p2p_random(char *buf, size_t len)
 {
 	u8 val;
 	size_t i;
 	u8 letters = 'Z' - 'A' + 1;
 	u8 numbers = 10;

 	if (os_get_random((unsigned char *) buf, len))
 		return -1;
 	/* Character set: 'A'-'Z', 'a'-'z', '0'-'9' */
 	for (i = 0; i < len; i++) {
 		val = buf[i];
 		val %= 2 * letters + numbers;
 		if (val < letters)
 			buf[i] = 'A' + val;
 		else if (val < 2 * letters)
 			buf[i] = 'a' + (val - letters);
 		else
 			buf[i] = '0' + (val - 2 * letters);
 	}

 	return 0;
 }


 /**
  * p2p_channel_to_freq - Convert channel info to frequency
  * @op_class: Operating class
  * @channel: Channel number
  * Returns: Frequency in MHz or -1 if the specified channel is unknown
  */
 int p2p_channel_to_freq(int op_class, int channel)
 {
 	return ieee80211_chan_to_freq(NULL, op_class, channel);
 }


 /**
  * p2p_freq_to_channel - Convert frequency into channel info
  * @op_class: Buffer for returning operating class
  * @channel: Buffer for returning channel number
  * Returns: 0 on success, -1 if the specified frequency is unknown
  */
 int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)
 {
 	if (ieee80211_freq_to_channel_ext(freq, 0, 0, op_class, channel) ==
 	    NUM_HOSTAPD_MODES)
 		return -1;

 	return 0;
 }


 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
 				    const struct p2p_reg_class *b,
 				    struct p2p_reg_class *res)
 {
 	size_t i, j;

 	res->reg_class = a->reg_class;

 	for (i = 0; i < a->channels; i++) {
 		for (j = 0; j < b->channels; j++) {
 			if (a->channel[i] != b->channel[j])
 				continue;
 			res->channel[res->channels] = a->channel[i];
 			res->channels++;
 			if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
 				return;
 		}
 	}
 }


 /**
  * p2p_channels_intersect - Intersection of supported channel lists
  * @a: First set of supported channels
  * @b: Second set of supported channels
  * @res: Data structure for returning the intersection of support channels
  *
  * This function can be used to find a common set of supported channels. Both
  * input channels sets are assumed to use the same country code. If different
  * country codes are used, the regulatory class numbers may not be matched
  * correctly and results are undefined.
  */
 void p2p_channels_intersect(const struct p2p_channels *a,
 			    const struct p2p_channels *b,
 			    struct p2p_channels *res)
 {
 	size_t i, j;

 	os_memset(res, 0, sizeof(*res));

 	for (i = 0; i < a->reg_classes; i++) {
 		const struct p2p_reg_class *a_reg = &a->reg_class[i];
 		for (j = 0; j < b->reg_classes; j++) {
 			const struct p2p_reg_class *b_reg = &b->reg_class[j];
 			if (a_reg->reg_class != b_reg->reg_class)
 				continue;
 			p2p_reg_class_intersect(
 				a_reg, b_reg,
 				&res->reg_class[res->reg_classes]);
 			if (res->reg_class[res->reg_classes].channels) {
 				res->reg_classes++;
 				if (res->reg_classes == P2P_MAX_REG_CLASSES)
 					return;
 			}
 		}
 	}
 }


 static void p2p_op_class_union(struct p2p_reg_class *cl,
 			       const struct p2p_reg_class *b_cl)
 {
 	size_t i, j;

 	for (i = 0; i < b_cl->channels; i++) {
 		for (j = 0; j < cl->channels; j++) {
 			if (b_cl->channel[i] == cl->channel[j])
 				break;
 		}
 		if (j == cl->channels) {
 			if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
 				return;
 			cl->channel[cl->channels++] = b_cl->channel[i];
 		}
 	}
 }


 /**
  * p2p_channels_union_inplace - Inplace union of channel lists
  * @res: Input data and place for returning union of the channel sets
  * @b: Second set of channels
  */
 void p2p_channels_union_inplace(struct p2p_channels *res,
 				const struct p2p_channels *b)
 {
 	size_t i, j;

 	for (i = 0; i < res->reg_classes; i++) {
 		struct p2p_reg_class *cl = &res->reg_class[i];
 		for (j = 0; j < b->reg_classes; j++) {
 			const struct p2p_reg_class *b_cl = &b->reg_class[j];
 			if (cl->reg_class != b_cl->reg_class)
 				continue;
 			p2p_op_class_union(cl, b_cl);
 		}
 	}

 	for (j = 0; j < b->reg_classes; j++) {
 		const struct p2p_reg_class *b_cl = &b->reg_class[j];

 		for (i = 0; i < res->reg_classes; i++) {
 			struct p2p_reg_class *cl = &res->reg_class[i];
 			if (cl->reg_class == b_cl->reg_class)
 				break;
 		}

 		if (i == res->reg_classes) {
 			if (res->reg_classes == P2P_MAX_REG_CLASSES)
 				return;
 			os_memcpy(&res->reg_class[res->reg_classes++],
 				  b_cl, sizeof(struct p2p_reg_class));
 		}
 	}
 }


 /**
  * p2p_channels_union - Union of channel lists
  * @a: First set of channels
  * @b: Second set of channels
  * @res: Data structure for returning the union of channels
  */
 void p2p_channels_union(const struct p2p_channels *a,
 			const struct p2p_channels *b,
 			struct p2p_channels *res)
 {
 	os_memcpy(res, a, sizeof(*res));
 	p2p_channels_union_inplace(res, b);
 }


 void p2p_channels_remove_freqs(struct p2p_channels *chan,
 			       const struct wpa_freq_range_list *list)
 {
 	size_t o, c;

 	if (list == NULL)
 		return;

 	o = 0;
 	while (o < chan->reg_classes) {
 		struct p2p_reg_class *op = &chan->reg_class[o];

 		c = 0;
 		while (c < op->channels) {
 			int freq = p2p_channel_to_freq(op->reg_class,
 						       op->channel[c]);
 			if (freq > 0 && freq_range_list_includes(list, freq)) {
 				op->channels--;
 				os_memmove(&op->channel[c],
 					   &op->channel[c + 1],
 					   op->channels - c);
 			} else
 				c++;
 		}

 		if (op->channels == 0) {
 			chan->reg_classes--;
 			os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
 				   (chan->reg_classes - o) *
 				   sizeof(struct p2p_reg_class));
 		} else
 			o++;
 	}
 }


 /**
  * p2p_channels_includes - Check whether a channel is included in the list
  * @channels: List of supported channels
  * @reg_class: Regulatory class of the channel to search
  * @channel: Channel number of the channel to search
  * Returns: 1 if channel was found or 0 if not
  */
 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
 			  u8 channel)
 {
 	size_t i, j;
 	for (i = 0; i < channels->reg_classes; i++) {
 		const struct p2p_reg_class *reg = &channels->reg_class[i];
 		if (reg->reg_class != reg_class)
 			continue;
 		for (j = 0; j < reg->channels; j++) {
 			if (reg->channel[j] == channel)
 				return 1;
 		}
 	}
 	return 0;
 }


 int p2p_channels_includes_freq(const struct p2p_channels *channels,
 			       unsigned int freq)
 {
 	size_t i, j;
 	for (i = 0; i < channels->reg_classes; i++) {
 		const struct p2p_reg_class *reg = &channels->reg_class[i];
 		for (j = 0; j < reg->channels; j++) {
 			if (p2p_channel_to_freq(reg->reg_class,
 						reg->channel[j]) == (int) freq)
 				return 1;
 		}
 	}
 	return 0;
 }


 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
 {
 	u8 op_reg_class, op_channel;
 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 		return 0;
 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 				     op_channel);
 }


 int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
 {
 	u8 op_reg_class, op_channel;
 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 		return 0;
 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 				     op_channel) &&
 		!freq_range_list_includes(&p2p->no_go_freq, freq);
 }


 int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
 {
 	u8 op_reg_class, op_channel;
 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 		return 0;
 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 				     op_channel) ||
 		p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
 				      op_channel);
 }


 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
 			       const struct p2p_channels *channels)
 {
 	unsigned int i;
 	int freq = 0;
 	const struct p2p_channels *tmpc = channels ?
 		channels : &p2p->cfg->channels;

 	if (tmpc == NULL)
 		return 0;

 	for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
 		freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
 					   p2p->cfg->pref_chan[i].chan);
 		if (p2p_channels_includes_freq(tmpc, freq))
 			return freq;
 	}
 	return 0;
 }


 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 		       const struct p2p_channels *chan)
 {
 	char buf[500], *pos, *end;
 	size_t i, j;
 	int ret;

 	pos = buf;
 	end = pos + sizeof(buf);

 	for (i = 0; i < chan->reg_classes; i++) {
 		const struct p2p_reg_class *c;
 		c = &chan->reg_class[i];
 		ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
 		if (os_snprintf_error(end - pos, ret))
 			break;
 		pos += ret;

 		for (j = 0; j < c->channels; j++) {
 			ret = os_snprintf(pos, end - pos, "%s%u",
 					  j == 0 ? "" : ",",
 					  c->channel[j]);
 			if (os_snprintf_error(end - pos, ret))
 				break;
 			pos += ret;
 		}
 	}
 	*pos = '\0';

 	p2p_dbg(p2p, "%s:%s", title, buf);
 }


 static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)
 {
 	unsigned int r;
 	if (os_get_random((u8 *) &r, sizeof(r)) < 0)
 		r = 0;
 	r %= num_channels;
 	return channels[r];
 }


 int p2p_channel_select(struct p2p_channels *chans, const int *classes,
 		       u8 *op_class, u8 *op_channel)
 {
 	unsigned int i, j;

 	for (j = 0; classes == NULL || classes[j]; j++) {
 		for (i = 0; i < chans->reg_classes; i++) {
 			struct p2p_reg_class *c = &chans->reg_class[i];

 			if (c->channels == 0)
 				continue;

 			if (classes == NULL || c->reg_class == classes[j]) {
 				/*
 				 * Pick one of the available channels in the
 				 * operating class at random.
 				 */
 				*op_class = c->reg_class;
 				*op_channel = p2p_channel_pick_random(
 					c->channel, c->channels);
 				return 0;
 			}
 		}
 		if (classes == NULL)
 			break;
 	}

 	return -1;
 }


 int p2p_channel_random_social(struct p2p_channels *chans, u8 *op_class,
 			      u8 *op_channel)
 {
 	u8 chan[4];
 	unsigned int num_channels = 0;

 	/* Try to find available social channels from 2.4 GHz */
 	if (p2p_channels_includes(chans, 81, 1))
 		chan[num_channels++] = 1;
 	if (p2p_channels_includes(chans, 81, 6))
 		chan[num_channels++] = 6;
 	if (p2p_channels_includes(chans, 81, 11))
 		chan[num_channels++] = 11;

 	/* Try to find available social channels from 60 GHz */
 	if (p2p_channels_includes(chans, 180, 2))
 		chan[num_channels++] = 2;

 	if (num_channels == 0)
 		return -1;

 	*op_channel = p2p_channel_pick_random(chan, num_channels);
 	if (*op_channel == 2)
 		*op_class = 180;
 	else
 		*op_class = 81;

 	return 0;
 }


 int p2p_channels_to_freqs(const struct p2p_channels *channels, int *freq_list,
 			  unsigned int max_len)
 {
 	unsigned int i, idx;

 	if (!channels || max_len == 0)
 		return 0;

 	for (i = 0, idx = 0; i < channels->reg_classes; i++) {
 		const struct p2p_reg_class *c = &channels->reg_class[i];
 		unsigned int j;

 		if (idx + 1 == max_len)
 			break;
 		for (j = 0; j < c->channels; j++) {
 			int freq;
 			unsigned int k;

 			if (idx + 1 == max_len)
 				break;
 			freq = p2p_channel_to_freq(c->reg_class,
 						   c->channel[j]);
 			if (freq < 0)
 				continue;

 			for (k = 0; k < idx; k++) {
 				if (freq_list[k] == freq)
 					break;
 			}

 			if (k < idx)
 				continue;
 			freq_list[idx++] = freq;
 		}
 	}

 	freq_list[idx] = 0;

 	return idx;
 }
	/*
	* P2P - generic helper functions
	* Copyright (c) 2009, Atheros Communications
	*
	* This software may be distributed under the terms of the BSD license.
	* See README for more details.
	*/

	#include "includes.h"

	#include "common.h"
	#include "common/defs.h"
	#include "common/ieee802_11_common.h"
	#include "p2p_i.h"


	/**
	* p2p_random - Generate random string for SSID and passphrase
	* @buf: Buffer for returning the result
	* @len: Number of octets to write to the buffer
	* Returns: 0 on success, -1 on failure
	*
	* This function generates a random string using the following character set:
	* 'A'-'Z', 'a'-'z', '0'-'9'.
	*/
	int p2p_random(char *buf, size_t len)
	{
	u8 val;
	size_t i;
	u8 letters = 'Z' - 'A' + 1;
	u8 numbers = 10;

	if (os_get_random((unsigned char *) buf, len))
	return -1;
	/* Character set: 'A'-'Z', 'a'-'z', '0'-'9' */
	for (i = 0; i < len; i++) {
	val = buf[i];
	val %= 2 * letters + numbers;
	if (val < letters)
	buf[i] = 'A' + val;
	else if (val < 2 * letters)
	buf[i] = 'a' + (val - letters);
	else
	buf[i] = '0' + (val - 2 * letters);
	}

	return 0;
	}


	/**
	* p2p_channel_to_freq - Convert channel info to frequency
	* @op_class: Operating class
	* @channel: Channel number
	* Returns: Frequency in MHz or -1 if the specified channel is unknown
	*/
	int p2p_channel_to_freq(int op_class, int channel)
	{
	return ieee80211_chan_to_freq(NULL, op_class, channel);
	}


	/**
	* p2p_freq_to_channel - Convert frequency into channel info
	* @op_class: Buffer for returning operating class
	* @channel: Buffer for returning channel number
	* Returns: 0 on success, -1 if the specified frequency is unknown
	*/
	int p2p_freq_to_channel(unsigned int freq, u8 op_class, u8 channel)
	{
	if (ieee80211_freq_to_channel_ext(freq, 0, 0, op_class, channel) ==
	NUM_HOSTAPD_MODES)
	return -1;

	return 0;
	}


	static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
	const struct p2p_reg_class *b,
	struct p2p_reg_class *res)
	{
	size_t i, j;

	res->reg_class = a->reg_class;

	for (i = 0; i < a->channels; i++) {
	for (j = 0; j < b->channels; j++) {
	if (a->channel[i] != b->channel[j])
	continue;
	res->channel[res->channels] = a->channel[i];
	res->channels++;
	if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
	return;
	}
	}
	}


	/**
	* p2p_channels_intersect - Intersection of supported channel lists
	* @a: First set of supported channels
	* @b: Second set of supported channels
	* @res: Data structure for returning the intersection of support channels
	*
	* This function can be used to find a common set of supported channels. Both
	* input channels sets are assumed to use the same country code. If different
	* country codes are used, the regulatory class numbers may not be matched
	* correctly and results are undefined.
	*/
	void p2p_channels_intersect(const struct p2p_channels *a,
	const struct p2p_channels *b,
	struct p2p_channels *res)
	{
	size_t i, j;

	os_memset(res, 0, sizeof(*res));

	for (i = 0; i < a->reg_classes; i++) {
	const struct p2p_reg_class *a_reg = &a->reg_class[i];
	for (j = 0; j < b->reg_classes; j++) {
	const struct p2p_reg_class *b_reg = &b->reg_class[j];
	if (a_reg->reg_class != b_reg->reg_class)
	continue;
	p2p_reg_class_intersect(
	a_reg, b_reg,
	&res->reg_class[res->reg_classes]);
	if (res->reg_class[res->reg_classes].channels) {
	res->reg_classes++;
	if (res->reg_classes == P2P_MAX_REG_CLASSES)
	return;
	}
	}
	}
	}


	static void p2p_op_class_union(struct p2p_reg_class *cl,
	const struct p2p_reg_class *b_cl)
	{
	size_t i, j;

	for (i = 0; i < b_cl->channels; i++) {
	for (j = 0; j < cl->channels; j++) {
	if (b_cl->channel[i] == cl->channel[j])
	break;
	}
	if (j == cl->channels) {
	if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
	return;
	cl->channel[cl->channels++] = b_cl->channel[i];
	}
	}
	}


	/**
	* p2p_channels_union_inplace - Inplace union of channel lists
	* @res: Input data and place for returning union of the channel sets
	* @b: Second set of channels
	*/
	void p2p_channels_union_inplace(struct p2p_channels *res,
	const struct p2p_channels *b)
	{
	size_t i, j;

	for (i = 0; i < res->reg_classes; i++) {
	struct p2p_reg_class *cl = &res->reg_class[i];
	for (j = 0; j < b->reg_classes; j++) {
	const struct p2p_reg_class *b_cl = &b->reg_class[j];
	if (cl->reg_class != b_cl->reg_class)
	continue;
	p2p_op_class_union(cl, b_cl);
	}
	}

	for (j = 0; j < b->reg_classes; j++) {
	const struct p2p_reg_class *b_cl = &b->reg_class[j];

	for (i = 0; i < res->reg_classes; i++) {
	struct p2p_reg_class *cl = &res->reg_class[i];
	if (cl->reg_class == b_cl->reg_class)
	break;
	}

	if (i == res->reg_classes) {
	if (res->reg_classes == P2P_MAX_REG_CLASSES)
	return;
	os_memcpy(&res->reg_class[res->reg_classes++],
	b_cl, sizeof(struct p2p_reg_class));
	}
	}
	}


	/**
	* p2p_channels_union - Union of channel lists
	* @a: First set of channels
	* @b: Second set of channels
	* @res: Data structure for returning the union of channels
	*/
	void p2p_channels_union(const struct p2p_channels *a,
	const struct p2p_channels *b,
	struct p2p_channels *res)
	{
	os_memcpy(res, a, sizeof(*res));
	p2p_channels_union_inplace(res, b);
	}


	void p2p_channels_remove_freqs(struct p2p_channels *chan,
	const struct wpa_freq_range_list *list)
	{
	size_t o, c;

	if (list == NULL)
	return;

	o = 0;
	while (o < chan->reg_classes) {
	struct p2p_reg_class *op = &chan->reg_class[o];

	c = 0;
	while (c < op->channels) {
	int freq = p2p_channel_to_freq(op->reg_class,
	op->channel[c]);
	if (freq > 0 && freq_range_list_includes(list, freq)) {
	op->channels--;
	os_memmove(&op->channel[c],
	&op->channel[c + 1],
	op->channels - c);
	} else
	c++;
	}

	if (op->channels == 0) {
	chan->reg_classes--;
	os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
	(chan->reg_classes - o) *
	sizeof(struct p2p_reg_class));
	} else
	o++;
	}
	}


	/**
	* p2p_channels_includes - Check whether a channel is included in the list
	* @channels: List of supported channels
	* @reg_class: Regulatory class of the channel to search
	* @channel: Channel number of the channel to search
	* Returns: 1 if channel was found or 0 if not
	*/
	int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
	u8 channel)
	{
	size_t i, j;
	for (i = 0; i < channels->reg_classes; i++) {
	const struct p2p_reg_class *reg = &channels->reg_class[i];
	if (reg->reg_class != reg_class)
	continue;
	for (j = 0; j < reg->channels; j++) {
	if (reg->channel[j] == channel)
	return 1;
	}
	}
	return 0;
	}


	int p2p_channels_includes_freq(const struct p2p_channels *channels,
	unsigned int freq)
	{
	size_t i, j;
	for (i = 0; i < channels->reg_classes; i++) {
	const struct p2p_reg_class *reg = &channels->reg_class[i];
	for (j = 0; j < reg->channels; j++) {
	if (p2p_channel_to_freq(reg->reg_class,
	reg->channel[j]) == (int) freq)
	return 1;
	}
	}
	return 0;
	}


	int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
	{
	u8 op_reg_class, op_channel;
	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
	return 0;
	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
	op_channel);
	}


	int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
	{
	u8 op_reg_class, op_channel;
	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
	return 0;
	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
	op_channel) &&
	!freq_range_list_includes(&p2p->no_go_freq, freq);
	}


	int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
	{
	u8 op_reg_class, op_channel;
	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
	return 0;
	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
	op_channel) \|\|
	p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
	op_channel);
	}


	unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
	const struct p2p_channels *channels)
	{
	unsigned int i;
	int freq = 0;
	const struct p2p_channels *tmpc = channels ?
	channels : &p2p->cfg->channels;

	if (tmpc == NULL)
	return 0;

	for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
	freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
	p2p->cfg->pref_chan[i].chan);
	if (p2p_channels_includes_freq(tmpc, freq))
	return freq;
	}
	return 0;
	}


	void p2p_channels_dump(struct p2p_data p2p, const char title,
	const struct p2p_channels *chan)
	{
	char buf[500], pos, end;
	size_t i, j;
	int ret;

	pos = buf;
	end = pos + sizeof(buf);

	for (i = 0; i < chan->reg_classes; i++) {
	const struct p2p_reg_class *c;
	c = &chan->reg_class[i];
	ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
	if (os_snprintf_error(end - pos, ret))
	break;
	pos += ret;

	for (j = 0; j < c->channels; j++) {
	ret = os_snprintf(pos, end - pos, "%s%u",
	j == 0 ? "" : ",",
	c->channel[j]);
	if (os_snprintf_error(end - pos, ret))
	break;
	pos += ret;
	}
	}
	*pos = '\0';

	p2p_dbg(p2p, "%s:%s", title, buf);
	}


	static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)
	{
	unsigned int r;
	if (os_get_random((u8 *) &r, sizeof(r)) < 0)
	r = 0;
	r %= num_channels;
	return channels[r];
	}


	int p2p_channel_select(struct p2p_channels chans, const int classes,
	u8 op_class, u8 op_channel)
	{
	unsigned int i, j;

	for (j = 0; classes == NULL \|\| classes[j]; j++) {
	for (i = 0; i < chans->reg_classes; i++) {
	struct p2p_reg_class *c = &chans->reg_class[i];

	if (c->channels == 0)
	continue;

	if (classes == NULL \|\| c->reg_class == classes[j]) {
	/*
	* Pick one of the available channels in the
	* operating class at random.
	*/
	*op_class = c->reg_class;
	*op_channel = p2p_channel_pick_random(
	c->channel, c->channels);
	return 0;
	}
	}
	if (classes == NULL)
	break;
	}

	return -1;
	}


	int p2p_channel_random_social(struct p2p_channels chans, u8 op_class,
	u8 *op_channel)
	{
	u8 chan[4];
	unsigned int num_channels = 0;

	/* Try to find available social channels from 2.4 GHz */
	if (p2p_channels_includes(chans, 81, 1))
	chan[num_channels++] = 1;
	if (p2p_channels_includes(chans, 81, 6))
	chan[num_channels++] = 6;
	if (p2p_channels_includes(chans, 81, 11))
	chan[num_channels++] = 11;

	/* Try to find available social channels from 60 GHz */
	if (p2p_channels_includes(chans, 180, 2))
	chan[num_channels++] = 2;

	if (num_channels == 0)
	return -1;

	*op_channel = p2p_channel_pick_random(chan, num_channels);
	if (*op_channel == 2)
	*op_class = 180;
	else
	*op_class = 81;

	return 0;
	}


	int p2p_channels_to_freqs(const struct p2p_channels channels, int freq_list,
	unsigned int max_len)
	{
	unsigned int i, idx;

	if (!channels \|\| max_len == 0)
	return 0;

	for (i = 0, idx = 0; i < channels->reg_classes; i++) {
	const struct p2p_reg_class *c = &channels->reg_class[i];
	unsigned int j;

	if (idx + 1 == max_len)
	break;
	for (j = 0; j < c->channels; j++) {
	int freq;
	unsigned int k;

	if (idx + 1 == max_len)
	break;
	freq = p2p_channel_to_freq(c->reg_class,
	c->channel[j]);
	if (freq < 0)
	continue;

	for (k = 0; k < idx; k++) {
	if (freq_list[k] == freq)
	break;
	}

	if (k < idx)
	continue;
	freq_list[idx++] = freq;
	}
	}

	freq_list[idx] = 0;

	return idx;
	}