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/*
* mac80211 - channel management
*/
#include <linux/nl80211.h>
#include <net/cfg80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
static bool
ieee80211_channel_types_are_compatible(enum nl80211_channel_type chantype1,
enum nl80211_channel_type chantype2,
enum nl80211_channel_type *compat)
{
/*
* start out with chantype1 being the result,
* overwriting later if needed
*/
if (compat)
*compat = chantype1;
switch (chantype1) {
case NL80211_CHAN_NO_HT:
if (compat)
*compat = chantype2;
break;
case NL80211_CHAN_HT20:
/*
* allow any change that doesn't go to no-HT
* (if it already is no-HT no change is needed)
*/
if (chantype2 == NL80211_CHAN_NO_HT)
break;
if (compat)
*compat = chantype2;
break;
case NL80211_CHAN_HT40PLUS:
case NL80211_CHAN_HT40MINUS:
/* allow smaller bandwidth and same */
if (chantype2 == NL80211_CHAN_NO_HT)
break;
if (chantype2 == NL80211_CHAN_HT20)
break;
if (chantype2 == chantype1)
break;
return false;
}
return true;
}
static void ieee80211_change_chantype(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx,
enum nl80211_channel_type chantype)
{
if (chantype == ctx->conf.channel_type)
return;
ctx->conf.channel_type = chantype;
drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_CHANNEL_TYPE);
if (!local->use_chanctx) {
local->_oper_channel_type = chantype;
ieee80211_hw_config(local, 0);
}
}
static struct ieee80211_chanctx *
ieee80211_find_chanctx(struct ieee80211_local *local,
struct ieee80211_channel *channel,
enum nl80211_channel_type channel_type,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_chanctx *ctx;
enum nl80211_channel_type compat_type;
lockdep_assert_held(&local->chanctx_mtx);
if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
return NULL;
if (WARN_ON(!channel))
return NULL;
list_for_each_entry(ctx, &local->chanctx_list, list) {
compat_type = ctx->conf.channel_type;
if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
continue;
if (ctx->conf.channel != channel)
continue;
if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
channel_type,
&compat_type))
continue;
ieee80211_change_chantype(local, ctx, compat_type);
return ctx;
}
return NULL;
}
static struct ieee80211_chanctx *
ieee80211_new_chanctx(struct ieee80211_local *local,
struct ieee80211_channel *channel,
enum nl80211_channel_type channel_type,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_chanctx *ctx;
int err;
lockdep_assert_held(&local->chanctx_mtx);
ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->conf.channel = channel;
ctx->conf.channel_type = channel_type;
ctx->mode = mode;
if (!local->use_chanctx) {
local->_oper_channel_type = channel_type;
local->_oper_channel = channel;
ieee80211_hw_config(local, 0);
} else {
err = drv_add_chanctx(local, ctx);
if (err) {
kfree(ctx);
return ERR_PTR(err);
}
}
list_add(&ctx->list, &local->chanctx_list);
return ctx;
}
static void ieee80211_free_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx)
{
lockdep_assert_held(&local->chanctx_mtx);
WARN_ON_ONCE(ctx->refcount != 0);
if (!local->use_chanctx) {
local->_oper_channel_type = NL80211_CHAN_NO_HT;
ieee80211_hw_config(local, 0);
} else {
drv_remove_chanctx(local, ctx);
}
list_del(&ctx->list);
kfree_rcu(ctx, rcu_head);
}
static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
struct ieee80211_chanctx *ctx)
{
struct ieee80211_local *local = sdata->local;
int ret;
lockdep_assert_held(&local->chanctx_mtx);
ret = drv_assign_vif_chanctx(local, sdata, ctx);
if (ret)
return ret;
rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
ctx->refcount++;
return 0;
}
static enum nl80211_channel_type
ieee80211_calc_chantype(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx)
{
struct ieee80211_chanctx_conf *conf = &ctx->conf;
struct ieee80211_sub_if_data *sdata;
enum nl80211_channel_type result = NL80211_CHAN_NO_HT;
lockdep_assert_held(&local->chanctx_mtx);
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
continue;
WARN_ON_ONCE(!ieee80211_channel_types_are_compatible(
sdata->vif.bss_conf.channel_type,
result, &result));
}
rcu_read_unlock();
return result;
}
static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx)
{
enum nl80211_channel_type chantype;
lockdep_assert_held(&local->chanctx_mtx);
chantype = ieee80211_calc_chantype(local, ctx);
ieee80211_change_chantype(local, ctx, chantype);
}
static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
struct ieee80211_chanctx *ctx)
{
struct ieee80211_local *local = sdata->local;
lockdep_assert_held(&local->chanctx_mtx);
ctx->refcount--;
rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
drv_unassign_vif_chanctx(local, sdata, ctx);
if (ctx->refcount > 0)
ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
}
static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx_conf *conf;
struct ieee80211_chanctx *ctx;
lockdep_assert_held(&local->chanctx_mtx);
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf)
return;
ctx = container_of(conf, struct ieee80211_chanctx, conf);
ieee80211_unassign_vif_chanctx(sdata, ctx);
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
}
int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
struct ieee80211_channel *channel,
enum nl80211_channel_type channel_type,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx *ctx;
int ret;
WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
mutex_lock(&local->chanctx_mtx);
__ieee80211_vif_release_channel(sdata);
ctx = ieee80211_find_chanctx(local, channel, channel_type, mode);
if (!ctx)
ctx = ieee80211_new_chanctx(local, channel, channel_type, mode);
if (IS_ERR(ctx)) {
ret = PTR_ERR(ctx);
goto out;
}
sdata->vif.bss_conf.channel_type = channel_type;
ret = ieee80211_assign_vif_chanctx(sdata, ctx);
if (ret) {
/* if assign fails refcount stays the same */
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
goto out;
}
out:
mutex_unlock(&local->chanctx_mtx);
return ret;
}
void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
{
WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
mutex_lock(&sdata->local->chanctx_mtx);
__ieee80211_vif_release_channel(sdata);
mutex_unlock(&sdata->local->chanctx_mtx);
}
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