/*
* 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,
struct wpa_freq_range_list *avoid_list,
struct wpa_freq_range_list *disallow_list)
{
u8 chan[4];
unsigned int num_channels = 0;
/* Try to find available social channels from 2.4 GHz.
* If the avoid_list includes any of the 2.4 GHz social channels, that
* channel is not allowed by p2p_channels_includes() rules. However, it
* is assumed to allow minimal traffic for P2P negotiation, so allow it
* here for social channel selection unless explicitly disallowed in the
* disallow_list. */
if (p2p_channels_includes(chans, 81, 1) ||
(freq_range_list_includes(avoid_list, 2412) &&
!freq_range_list_includes(disallow_list, 2412)))
chan[num_channels++] = 1;
if (p2p_channels_includes(chans, 81, 6) ||
(freq_range_list_includes(avoid_list, 2437) &&
!freq_range_list_includes(disallow_list, 2437)))
chan[num_channels++] = 6;
if (p2p_channels_includes(chans, 81, 11) ||
(freq_range_list_includes(avoid_list, 2462) &&
!freq_range_list_includes(disallow_list, 2462)))
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;
}