/*
* 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;
}
static int p2p_channel_to_freq_j4(int reg_class, int channel)
{
/* Table J-4 in P802.11REVmb/D4.0 - Global operating classes */
/* TODO: more regulatory classes */
switch (reg_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_channel_to_freq - Convert channel info to frequency
* @country: Country code
* @reg_class: Regulatory class
* @channel: Channel number
* Returns: Frequency in MHz or -1 if the specified channel is unknown
*/
int p2p_channel_to_freq(const char *country, int reg_class, int channel)
{
if (country[2] == 0x04)
return p2p_channel_to_freq_j4(reg_class, channel);
/* These are mainly for backwards compatibility; to be removed */
switch (reg_class) {
case 1: /* US/1, EU/1, JP/1 = 5 GHz, channels 36,40,44,48 */
if (channel < 36 || channel > 48)
return -1;
return 5000 + 5 * channel;
case 3: /* US/3 = 5 GHz, channels 149,153,157,161 */
case 5: /* US/5 = 5 GHz, channels 149,153,157,161 */
if (channel < 149 || channel > 161)
return -1;
return 5000 + 5 * channel;
case 4: /* EU/4 = 2.407 GHz, channels 1..13 */
case 12: /* US/12 = 2.407 GHz, channels 1..11 */
case 30: /* JP/30 = 2.407 GHz, channels 1..13 */
if (channel < 1 || channel > 13)
return -1;
return 2407 + 5 * channel;
case 31: /* JP/31 = 2.414 GHz, channel 14 */
if (channel != 14)
return -1;
return 2414 + 5 * channel;
}
return -1;
}
/**
* p2p_freq_to_channel - Convert frequency into channel info
* @country: Country code
* @reg_class: Buffer for returning regulatory class
* @channel: Buffer for returning channel number
* Returns: 0 on success, -1 if the specified frequency is unknown
*/
int p2p_freq_to_channel(const char *country, unsigned int freq, u8 *reg_class,
u8 *channel)
{
/* TODO: more operating classes */
if (freq >= 2412 && freq <= 2472) {
*reg_class = 81; /* 2.407 GHz, channels 1..13 */
*channel = (freq - 2407) / 5;
return 0;
}
if (freq == 2484) {
*reg_class = 82; /* channel 14 */
*channel = 14;
return 0;
}
if (freq >= 5180 && freq <= 5240) {
*reg_class = 115; /* 5 GHz, channels 36..48 */
*channel = (freq - 5000) / 5;
return 0;
}
if (freq >= 5745 && freq <= 5805) {
*reg_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_supported_freq(struct p2p_data *p2p, unsigned int freq)
{
u8 op_reg_class, op_channel;
if (p2p_freq_to_channel(p2p->cfg->country, freq,
&op_reg_class, &op_channel) < 0)
return 0;
return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
op_channel);
}