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 "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)
 {
 	/* Table E-4 in IEEE Std 802.11-2012 - Global operating classes */
 	/* TODO: more operating classes */
 	switch (op_class) {
 	case 81:
 		/* channels 1..13 */
 		if (channel < 1 || channel > 13)
 			return -1;
 		return 2407 + 5 * channel;
 	case 82:
 		/* channel 14 */
 		if (channel != 14)
 			return -1;
 		return 2414 + 5 * channel;
 	case 83: /* channels 1..9; 40 MHz */
 	case 84: /* channels 5..13; 40 MHz */
 		if (channel < 1 || channel > 13)
 			return -1;
 		return 2407 + 5 * channel;
 	case 115: /* channels 36,40,44,48; indoor only */
 	case 118: /* channels 52,56,60,64; dfs */
 		if (channel < 36 || channel > 64)
 			return -1;
 		return 5000 + 5 * channel;
 	case 124: /* channels 149,153,157,161 */
 	case 125: /* channels 149,153,157,161,165,169 */
 		if (channel < 149 || channel > 161)
 			return -1;
 		return 5000 + 5 * channel;
 	case 116: /* channels 36,44; 40 MHz; indoor only */
 	case 117: /* channels 40,48; 40 MHz; indoor only */
 	case 119: /* channels 52,60; 40 MHz; dfs */
 	case 120: /* channels 56,64; 40 MHz; dfs */
 		if (channel < 36 || channel > 64)
 			return -1;
 		return 5000 + 5 * channel;
 	case 126: /* channels 149,157; 40 MHz */
 	case 127: /* channels 153,161; 40 MHz */
 		if (channel < 149 || channel > 161)
 			return -1;
 		return 5000 + 5 * channel;
 	}
 	return -1;
 }


 /**
  * 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)
 {
 	/* TODO: more operating classes */
 	if (freq >= 2412 && freq <= 2472) {
 		if ((freq - 2407) % 5)
 			return -1;

 		*op_class = 81; /* 2.407 GHz, channels 1..13 */
 		*channel = (freq - 2407) / 5;
 		return 0;
 	}

 	if (freq == 2484) {
 		*op_class = 82; /* channel 14 */
 		*channel = 14;
 		return 0;
 	}

 	if (freq >= 5180 && freq <= 5240) {
 		if ((freq - 5000) % 5)
 			return -1;

 		*op_class = 115; /* 5 GHz, channels 36..48 */
 		*channel = (freq - 5000) / 5;
 		return 0;
 	}

 	if (freq >= 5745 && freq <= 5805) {
 		if ((freq - 5000) % 5)
 			return -1;

 		*op_class = 124; /* 5 GHz, channels 149..161 */
 		*channel = (freq - 5000) / 5;
 		return 0;
 	}

 	return -1;
 }


 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;
 			}
 		}
 	}
 }


 /**
  * 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;
 }


 #ifdef ANDROID_P2P
 static int p2p_block_op_freq(unsigned int freq)
 {
 	return (freq >= 5170 && freq < 5745);
 }


 size_t p2p_copy_reg_class(struct p2p_reg_class *dc, struct p2p_reg_class *sc)
 {
 	unsigned int i;

 	dc->reg_class = sc->reg_class;
 	dc->channels = 0;
 	for (i=0; i < sc->channels; i++) {
 		if (!p2p_block_op_freq(p2p_channel_to_freq(sc->reg_class,
 							   sc->channel[i]))) {
 			dc->channel[dc->channels] = sc->channel[i];
 			dc->channels++;
 		}
 	}
 	return dc->channels;
 }
 #endif


 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
 {
 	u8 op_reg_class, op_channel;

 #ifdef ANDROID_P2P
 	if (p2p_block_op_freq(freq))
 		return 0;
 #endif
 	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);
 }


 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
 			       const struct p2p_channels *channels)
 {
 	unsigned int i;
 	int freq = 0;

 	if (channels == NULL) {
 		if (p2p->cfg->num_pref_chan) {
 			freq = p2p_channel_to_freq(
 				p2p->cfg->pref_chan[0].op_class,
 				p2p->cfg->pref_chan[0].chan);
 			if (freq < 0)
 				freq = 0;
 		}
 		return freq;
 	}

 	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(channels, freq))
 			return freq;
 	}

 	return 0;
 }
	/*
	* 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 "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)
	{
	/* Table E-4 in IEEE Std 802.11-2012 - Global operating classes */
	/* TODO: more operating classes */
	switch (op_class) {
	case 81:
	/* channels 1..13 */
	if (channel < 1 \|\| channel > 13)
	return -1;
	return 2407 + 5 * channel;
	case 82:
	/* channel 14 */
	if (channel != 14)
	return -1;
	return 2414 + 5 * channel;
	case 83: /* channels 1..9; 40 MHz */
	case 84: /* channels 5..13; 40 MHz */
	if (channel < 1 \|\| channel > 13)
	return -1;
	return 2407 + 5 * channel;
	case 115: /* channels 36,40,44,48; indoor only */
	case 118: /* channels 52,56,60,64; dfs */
	if (channel < 36 \|\| channel > 64)
	return -1;
	return 5000 + 5 * channel;
	case 124: /* channels 149,153,157,161 */
	case 125: /* channels 149,153,157,161,165,169 */
	if (channel < 149 \|\| channel > 161)
	return -1;
	return 5000 + 5 * channel;
	case 116: /* channels 36,44; 40 MHz; indoor only */
	case 117: /* channels 40,48; 40 MHz; indoor only */
	case 119: /* channels 52,60; 40 MHz; dfs */
	case 120: /* channels 56,64; 40 MHz; dfs */
	if (channel < 36 \|\| channel > 64)
	return -1;
	return 5000 + 5 * channel;
	case 126: /* channels 149,157; 40 MHz */
	case 127: /* channels 153,161; 40 MHz */
	if (channel < 149 \|\| channel > 161)
	return -1;
	return 5000 + 5 * channel;
	}
	return -1;
	}


	/**
	* 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)
	{
	/* TODO: more operating classes */
	if (freq >= 2412 && freq <= 2472) {
	if ((freq - 2407) % 5)
	return -1;

	op_class = 81; / 2.407 GHz, channels 1..13 */
	*channel = (freq - 2407) / 5;
	return 0;
	}

	if (freq == 2484) {
	op_class = 82; / channel 14 */
	*channel = 14;
	return 0;
	}

	if (freq >= 5180 && freq <= 5240) {
	if ((freq - 5000) % 5)
	return -1;

	op_class = 115; / 5 GHz, channels 36..48 */
	*channel = (freq - 5000) / 5;
	return 0;
	}

	if (freq >= 5745 && freq <= 5805) {
	if ((freq - 5000) % 5)
	return -1;

	op_class = 124; / 5 GHz, channels 149..161 */
	*channel = (freq - 5000) / 5;
	return 0;
	}

	return -1;
	}


	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;
	}
	}
	}
	}


	/**
	* 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;
	}


	#ifdef ANDROID_P2P
	static int p2p_block_op_freq(unsigned int freq)
	{
	return (freq >= 5170 && freq < 5745);
	}


	size_t p2p_copy_reg_class(struct p2p_reg_class dc, struct p2p_reg_class sc)
	{
	unsigned int i;

	dc->reg_class = sc->reg_class;
	dc->channels = 0;
	for (i=0; i < sc->channels; i++) {
	if (!p2p_block_op_freq(p2p_channel_to_freq(sc->reg_class,
	sc->channel[i]))) {
	dc->channel[dc->channels] = sc->channel[i];
	dc->channels++;
	}
	}
	return dc->channels;
	}
	#endif


	int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
	{
	u8 op_reg_class, op_channel;

	#ifdef ANDROID_P2P
	if (p2p_block_op_freq(freq))
	return 0;
	#endif
	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);
	}


	unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
	const struct p2p_channels *channels)
	{
	unsigned int i;
	int freq = 0;

	if (channels == NULL) {
	if (p2p->cfg->num_pref_chan) {
	freq = p2p_channel_to_freq(
	p2p->cfg->pref_chan[0].op_class,
	p2p->cfg->pref_chan[0].chan);
	if (freq < 0)
	freq = 0;
	}
	return freq;
	}

	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(channels, freq))
	return freq;
	}

	return 0;
	}