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P2P: Clean up channel selection code to use helper functions

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This moves some of the p2p_prepare_channel_best() functionality into
separate helper functions to make the implementation easier to read.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2014-03-23 11:01:59 +02:00
parent 33c9b8d8ac
commit 6ace13a9e5
3 changed files with 54 additions and 45 deletions
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51
src/p2p/p2p.c
View file

@ -1214,46 +1214,19 @@ static void p2p_prepare_channel_best(struct p2p_data *p2p)
p2p_dbg(p2p, "Select pre-configured channel as operating channel preference");
p2p->op_reg_class = p2p->cfg->op_reg_class;
p2p->op_channel = p2p->cfg->op_channel;
} else if (p2p_channel_random_social(&p2p->cfg->channels,
&p2p->op_reg_class,
&p2p->op_channel) == 0) {
p2p_dbg(p2p, "Select random available social channel %d from 2.4 GHz band as operating channel preference",
p2p->op_channel);
} else {
u8 op_chans[3];
u8 *op_chan;
size_t num_channels = 0;
unsigned int r;
/* Try to find available social channels from 2.4 GHz */
if (p2p_channels_includes(&p2p->cfg->channels, 81, 1))
op_chans[num_channels++] = 1;
if (p2p_channels_includes(&p2p->cfg->channels, 81, 6))
op_chans[num_channels++] = 6;
if (p2p_channels_includes(&p2p->cfg->channels, 81, 11))
op_chans[num_channels++] = 11;
if (num_channels) {
p2p_dbg(p2p, "Select random available social channel from 2.4 GHz band as operating channel preference");
p2p->op_reg_class = 81;
op_chan = op_chans;
} else {
struct p2p_reg_class *class;
/* Select any random available channel from the first
* operating class */
p2p_dbg(p2p, "Select random available channel from operating class %d as operating channel preference",
p2p->op_reg_class);
class = &p2p->cfg->channels.reg_class[0];
p2p->op_reg_class = class->reg_class;
op_chan = &class->channel[0];
num_channels = class->channels;
if (num_channels == 0) {
/* Should not happen, but make sure we do not
* try to divide by zero */
op_chan = op_chans;
op_chans[0] = 1;
num_channels = 1;
}
}
os_get_random((u8 *) &r, sizeof(r));
r %= num_channels;
p2p->op_channel = op_chan[r];
/* Select any random available channel from the first available
* operating class */
p2p_channel_select(&p2p->cfg->channels, NULL,
&p2p->op_reg_class,
&p2p->op_channel);
p2p_dbg(p2p, "Select random available channel %d from operating class %d as operating channel preference",
p2p->op_channel, p2p->op_reg_class);
}
os_memcpy(&p2p->channels, &p2p->cfg->channels,

2
src/p2p/p2p_i.h
View file

@ -592,6 +592,8 @@ void p2p_channels_dump(struct p2p_data *p2p, const char *title,
const struct p2p_channels *chan);
int p2p_channel_select(struct p2p_channels *chans, const int *classes,
u8 *op_class, u8 *op_channel);
int p2p_channel_random_social(struct p2p_channels *chans, u8 *op_class,
u8 *op_channel);
/* p2p_parse.c */
int p2p_parse_p2p_ie(const struct wpabuf *buf, struct p2p_message *msg);

46
src/p2p/p2p_utils.c
View file

@ -441,31 +441,65 @@ void p2p_channels_dump(struct p2p_data *p2p, const char *title,
}
static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)
{
unsigned int r;
os_get_random((u8 *) &r, sizeof(r));
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, r;
unsigned int i, j;
for (j = 0; classes[j]; 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 (c->reg_class == classes[j]) {
if (classes == NULL || c->reg_class == classes[j]) {
/*
* Pick one of the available channels in the
* operating class at random.
*/
os_get_random((u8 *) &r, sizeof(r));
r %= c->channels;
*op_class = c->reg_class;
*op_channel = c->channel[r];
*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[3];
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;
if (num_channels == 0)
return -1;
*op_class = 81;
*op_channel = p2p_channel_pick_random(chan, num_channels);
return 0;
}