Having csa counters part of beacon and probe_resp
structures makes it easier to get rid of possible
races between setting a beacon and updating
counters on SMP systems by guaranteeing counters
are always consistent against given beacon struct.
While at it relax WARN_ON into WARN_ON_ONCE to
prevent spamming logs and racing.
Signed-off-by: Michal Kazior <michal.kazior@xxxxxxxxx>
---
Notes:
v2:
* fix unbalanced rcu locking
* use plural form of the word `offset` for variables
* define a struct to pass csa arguments to ieee80211_assign_beacon() [Johannes]
* fix lines with over 80 chars
v3:
* use sizeof(x[0]) instead of sizeof(*x) [Johannes]
net/mac80211/cfg.c | 67 +++++++++++++++++++----------
net/mac80211/ibss.c | 2 +-
net/mac80211/ieee80211_i.h | 16 +++++--
net/mac80211/mesh.c | 2 +-
net/mac80211/tx.c | 104 +++++++++++++++++++++++++--------------------
5 files changed, 116 insertions(+), 75 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index d7513a5..c17e624 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -875,7 +875,8 @@ static int ieee80211_set_monitor_channel(struct wiphy *wiphy,
}
static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
- const u8 *resp, size_t resp_len)
+ const u8 *resp, size_t resp_len,
+ const struct ieee80211_csa_settings *csa)
{
struct probe_resp *new, *old;
@@ -891,6 +892,11 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
new->len = resp_len;
memcpy(new->data, resp, resp_len);
+ if (csa)
+ memcpy(new->csa_counter_offsets, csa->counter_offsets_presp,
+ csa->n_counter_offsets_presp *
+ sizeof(new->csa_counter_offsets[0]));
+
rcu_assign_pointer(sdata->u.ap.probe_resp, new);
if (old)
kfree_rcu(old, rcu_head);
@@ -899,7 +905,8 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
}
static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
- struct cfg80211_beacon_data *params)
+ struct cfg80211_beacon_data *params,
+ const struct ieee80211_csa_settings *csa)
{
struct beacon_data *new, *old;
int new_head_len, new_tail_len;
@@ -943,6 +950,13 @@ static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
new->head_len = new_head_len;
new->tail_len = new_tail_len;
+ if (csa) {
+ new->csa_current_counter = csa->count;
+ memcpy(new->csa_counter_offsets, csa->counter_offsets_beacon,
+ csa->n_counter_offsets_beacon *
+ sizeof(new->csa_counter_offsets[0]));
+ }
+
/* copy in head */
if (params->head)
memcpy(new->head, params->head, new_head_len);
@@ -957,7 +971,7 @@ static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
memcpy(new->tail, old->tail, new_tail_len);
err = ieee80211_set_probe_resp(sdata, params->probe_resp,
- params->probe_resp_len);
+ params->probe_resp_len, csa);
if (err < 0)
return err;
if (err == 0)
@@ -1042,7 +1056,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
sdata->vif.bss_conf.p2p_noa_attr.oppps_ctwindow |=
IEEE80211_P2P_OPPPS_ENABLE_BIT;
- err = ieee80211_assign_beacon(sdata, ¶ms->beacon);
+ err = ieee80211_assign_beacon(sdata, ¶ms->beacon, NULL);
if (err < 0) {
ieee80211_vif_release_channel(sdata);
return err;
@@ -1090,7 +1104,7 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev,
if (!old)
return -ENOENT;
- err = ieee80211_assign_beacon(sdata, params);
+ err = ieee80211_assign_beacon(sdata, params, NULL);
if (err < 0)
return err;
ieee80211_bss_info_change_notify(sdata, err);
@@ -3073,7 +3087,8 @@ static int ieee80211_set_after_csa_beacon(struct ieee80211_sub_if_data *sdata,
switch (sdata->vif.type) {
case NL80211_IFTYPE_AP:
- err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
+ err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon,
+ NULL);
kfree(sdata->u.ap.next_beacon);
sdata->u.ap.next_beacon = NULL;
@@ -3176,6 +3191,7 @@ static int ieee80211_set_csa_beacon(struct ieee80211_sub_if_data *sdata,
struct cfg80211_csa_settings *params,
u32 *changed)
{
+ struct ieee80211_csa_settings csa = {};
int err;
switch (sdata->vif.type) {
@@ -3210,20 +3226,13 @@ static int ieee80211_set_csa_beacon(struct ieee80211_sub_if_data *sdata,
IEEE80211_MAX_CSA_COUNTERS_NUM))
return -EINVAL;
- /* make sure we don't have garbage in other counters */
- memset(sdata->csa_counter_offset_beacon, 0,
- sizeof(sdata->csa_counter_offset_beacon));
- memset(sdata->csa_counter_offset_presp, 0,
- sizeof(sdata->csa_counter_offset_presp));
-
- memcpy(sdata->csa_counter_offset_beacon,
- params->counter_offsets_beacon,
- params->n_counter_offsets_beacon * sizeof(u16));
- memcpy(sdata->csa_counter_offset_presp,
- params->counter_offsets_presp,
- params->n_counter_offsets_presp * sizeof(u16));
+ csa.counter_offsets_beacon = params->counter_offsets_beacon;
+ csa.counter_offsets_presp = params->counter_offsets_presp;
+ csa.n_counter_offsets_beacon = params->n_counter_offsets_beacon;
+ csa.n_counter_offsets_presp = params->n_counter_offsets_presp;
+ csa.count = params->count;
- err = ieee80211_assign_beacon(sdata, ¶ms->beacon_csa);
+ err = ieee80211_assign_beacon(sdata, ¶ms->beacon_csa, &csa);
if (err < 0) {
kfree(sdata->u.ap.next_beacon);
return err;
@@ -3367,7 +3376,6 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
sdata->csa_radar_required = params->radar_required;
sdata->csa_chandef = params->chandef;
sdata->csa_block_tx = params->block_tx;
- sdata->csa_current_counter = params->count;
sdata->vif.csa_active = true;
if (sdata->csa_block_tx)
@@ -3515,10 +3523,23 @@ static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
sdata->vif.type == NL80211_IFTYPE_ADHOC) &&
params->n_csa_offsets) {
int i;
- u8 c = sdata->csa_current_counter;
+ struct beacon_data *beacon = NULL;
- for (i = 0; i < params->n_csa_offsets; i++)
- data[params->csa_offsets[i]] = c;
+ rcu_read_lock();
+
+ if (sdata->vif.type == NL80211_IFTYPE_AP)
+ beacon = rcu_dereference(sdata->u.ap.beacon);
+ else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
+ beacon = rcu_dereference(sdata->u.ibss.presp);
+ else if (ieee80211_vif_is_mesh(&sdata->vif))
+ beacon = rcu_dereference(sdata->u.mesh.beacon);
+
+ if (beacon)
+ for (i = 0; i < params->n_csa_offsets; i++)
+ data[params->csa_offsets[i]] =
+ beacon->csa_current_counter;
+
+ rcu_read_unlock();
}
IEEE80211_SKB_CB(skb)->flags = flags;
diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 18ee0a2..713485f 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -143,7 +143,7 @@ ieee80211_ibss_build_presp(struct ieee80211_sub_if_data *sdata,
*pos++ = csa_settings->block_tx ? 1 : 0;
*pos++ = ieee80211_frequency_to_channel(
csa_settings->chandef.chan->center_freq);
- sdata->csa_counter_offset_beacon[0] = (pos - presp->head);
+ presp->csa_counter_offsets[0] = (pos - presp->head);
*pos++ = csa_settings->count;
}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index ed2b817..998c18c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -229,16 +229,29 @@ struct ieee80211_rx_data {
u16 tkip_iv16;
};
+struct ieee80211_csa_settings {
+ const u16 *counter_offsets_beacon;
+ const u16 *counter_offsets_presp;
+
+ int n_counter_offsets_beacon;
+ int n_counter_offsets_presp;
+
+ u8 count;
+};
+
struct beacon_data {
u8 *head, *tail;
int head_len, tail_len;
struct ieee80211_meshconf_ie *meshconf;
+ u16 csa_counter_offsets[IEEE80211_MAX_CSA_COUNTERS_NUM];
+ u8 csa_current_counter;
struct rcu_head rcu_head;
};
struct probe_resp {
struct rcu_head rcu_head;
int len;
+ u16 csa_counter_offsets[IEEE80211_MAX_CSA_COUNTERS_NUM];
u8 data[0];
};
@@ -753,8 +766,6 @@ struct ieee80211_sub_if_data {
struct mac80211_qos_map __rcu *qos_map;
struct work_struct csa_finalize_work;
- u16 csa_counter_offset_beacon[IEEE80211_MAX_CSA_COUNTERS_NUM];
- u16 csa_counter_offset_presp[IEEE80211_MAX_CSA_COUNTERS_NUM];
bool csa_radar_required;
bool csa_block_tx; /* write-protected by sdata_lock and local->mtx */
struct cfg80211_chan_def csa_chandef;
@@ -766,7 +777,6 @@ struct ieee80211_sub_if_data {
struct ieee80211_chanctx *reserved_chanctx;
struct cfg80211_chan_def reserved_chandef;
bool reserved_radar_required;
- u8 csa_current_counter;
/* used to reconfigure hardware SM PS */
struct work_struct recalc_smps;
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index da16468..e9f99c1 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -679,7 +679,7 @@ ieee80211_mesh_build_beacon(struct ieee80211_if_mesh *ifmsh)
*pos++ = 0x0;
*pos++ = ieee80211_frequency_to_channel(
csa->settings.chandef.chan->center_freq);
- sdata->csa_counter_offset_beacon[0] = hdr_len + 6;
+ bcn->csa_counter_offsets[0] = hdr_len + 6;
*pos++ = csa->settings.count;
*pos++ = WLAN_EID_CHAN_SWITCH_PARAM;
*pos++ = 6;
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 8170d99..ad5da6a 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2425,7 +2425,7 @@ static void ieee80211_set_csa(struct ieee80211_sub_if_data *sdata,
u8 *beacon_data;
size_t beacon_data_len;
int i;
- u8 count = sdata->csa_current_counter;
+ u8 count = beacon->csa_current_counter;
switch (sdata->vif.type) {
case NL80211_IFTYPE_AP:
@@ -2444,46 +2444,54 @@ static void ieee80211_set_csa(struct ieee80211_sub_if_data *sdata,
return;
}
+ rcu_read_lock();
for (i = 0; i < IEEE80211_MAX_CSA_COUNTERS_NUM; ++i) {
- u16 counter_offset_beacon =
- sdata->csa_counter_offset_beacon[i];
- u16 counter_offset_presp = sdata->csa_counter_offset_presp[i];
-
- if (counter_offset_beacon) {
- if (WARN_ON(counter_offset_beacon >= beacon_data_len))
- return;
-
- beacon_data[counter_offset_beacon] = count;
- }
-
- if (sdata->vif.type == NL80211_IFTYPE_AP &&
- counter_offset_presp) {
- rcu_read_lock();
- resp = rcu_dereference(sdata->u.ap.probe_resp);
+ resp = rcu_dereference(sdata->u.ap.probe_resp);
- /* If nl80211 accepted the offset, this should
- * not happen.
- */
- if (WARN_ON(!resp)) {
+ if (beacon->csa_counter_offsets[i]) {
+ if (WARN_ON_ONCE(beacon->csa_counter_offsets[i] >=
+ beacon_data_len)) {
rcu_read_unlock();
return;
}
- resp->data[counter_offset_presp] = count;
- rcu_read_unlock();
+
+ beacon_data[beacon->csa_counter_offsets[i]] = count;
}
+
+ if (sdata->vif.type == NL80211_IFTYPE_AP && resp &&
+ resp->csa_counter_offsets)
+ resp->data[resp->csa_counter_offsets[i]] = count;
}
+ rcu_read_unlock();
}
u8 ieee80211_csa_update_counter(struct ieee80211_vif *vif)
{
struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+ struct beacon_data *beacon = NULL;
+ u8 count = 0;
- sdata->csa_current_counter--;
+ rcu_read_lock();
+
+ if (sdata->vif.type == NL80211_IFTYPE_AP)
+ beacon = rcu_dereference(sdata->u.ap.beacon);
+ else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
+ beacon = rcu_dereference(sdata->u.ibss.presp);
+ else if (ieee80211_vif_is_mesh(&sdata->vif))
+ beacon = rcu_dereference(sdata->u.mesh.beacon);
+
+ if (!beacon)
+ goto unlock;
+
+ beacon->csa_current_counter--;
/* the counter should never reach 0 */
- WARN_ON(!sdata->csa_current_counter);
+ WARN_ON_ONCE(!beacon->csa_current_counter);
+ count = beacon->csa_current_counter;
- return sdata->csa_current_counter;
+unlock:
+ rcu_read_unlock();
+ return count;
}
EXPORT_SYMBOL(ieee80211_csa_update_counter);
@@ -2493,7 +2501,6 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
struct beacon_data *beacon = NULL;
u8 *beacon_data;
size_t beacon_data_len;
- int counter_beacon = sdata->csa_counter_offset_beacon[0];
int ret = false;
if (!ieee80211_sdata_running(sdata))
@@ -2531,10 +2538,10 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
goto out;
}
- if (WARN_ON(counter_beacon > beacon_data_len))
+ if (WARN_ON_ONCE(beacon->csa_counter_offsets[0] > beacon_data_len))
goto out;
- if (beacon_data[counter_beacon] == 1)
+ if (beacon_data[beacon->csa_counter_offsets[0]] == 1)
ret = true;
out:
rcu_read_unlock();
@@ -2550,6 +2557,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
bool is_template)
{
struct ieee80211_local *local = hw_to_local(hw);
+ struct beacon_data *beacon = NULL;
struct sk_buff *skb = NULL;
struct ieee80211_tx_info *info;
struct ieee80211_sub_if_data *sdata = NULL;
@@ -2571,8 +2579,8 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
if (sdata->vif.type == NL80211_IFTYPE_AP) {
struct ieee80211_if_ap *ap = &sdata->u.ap;
- struct beacon_data *beacon = rcu_dereference(ap->beacon);
+ beacon = rcu_dereference(ap->beacon);
if (beacon) {
if (sdata->vif.csa_active) {
if (!is_template)
@@ -2615,34 +2623,34 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
struct ieee80211_hdr *hdr;
- struct beacon_data *presp = rcu_dereference(ifibss->presp);
- if (!presp)
+ beacon = rcu_dereference(ifibss->presp);
+ if (!beacon)
goto out;
if (sdata->vif.csa_active) {
if (!is_template)
ieee80211_csa_update_counter(vif);
- ieee80211_set_csa(sdata, presp);
+ ieee80211_set_csa(sdata, beacon);
}
- skb = dev_alloc_skb(local->tx_headroom + presp->head_len +
+ skb = dev_alloc_skb(local->tx_headroom + beacon->head_len +
local->hw.extra_beacon_tailroom);
if (!skb)
goto out;
skb_reserve(skb, local->tx_headroom);
- memcpy(skb_put(skb, presp->head_len), presp->head,
- presp->head_len);
+ memcpy(skb_put(skb, beacon->head_len), beacon->head,
+ beacon->head_len);
hdr = (struct ieee80211_hdr *) skb->data;
hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_BEACON);
} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
- struct beacon_data *bcn = rcu_dereference(ifmsh->beacon);
- if (!bcn)
+ beacon = rcu_dereference(ifmsh->beacon);
+ if (!beacon)
goto out;
if (sdata->vif.csa_active) {
@@ -2654,40 +2662,42 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
*/
ieee80211_csa_update_counter(vif);
- ieee80211_set_csa(sdata, bcn);
+ ieee80211_set_csa(sdata, beacon);
}
if (ifmsh->sync_ops)
- ifmsh->sync_ops->adjust_tbtt(sdata, bcn);
+ ifmsh->sync_ops->adjust_tbtt(sdata, beacon);
skb = dev_alloc_skb(local->tx_headroom +
- bcn->head_len +
+ beacon->head_len +
256 + /* TIM IE */
- bcn->tail_len +
+ beacon->tail_len +
local->hw.extra_beacon_tailroom);
if (!skb)
goto out;
skb_reserve(skb, local->tx_headroom);
- memcpy(skb_put(skb, bcn->head_len), bcn->head, bcn->head_len);
+ memcpy(skb_put(skb, beacon->head_len), beacon->head,
+ beacon->head_len);
ieee80211_beacon_add_tim(sdata, &ifmsh->ps, skb, is_template);
if (offs) {
- offs->tim_offset = bcn->head_len;
- offs->tim_length = skb->len - bcn->head_len;
+ offs->tim_offset = beacon->head_len;
+ offs->tim_length = skb->len - beacon->head_len;
}
- memcpy(skb_put(skb, bcn->tail_len), bcn->tail, bcn->tail_len);
+ memcpy(skb_put(skb, beacon->tail_len), beacon->tail,
+ beacon->tail_len);
} else {
WARN_ON(1);
goto out;
}
/* CSA offsets */
- if (offs) {
+ if (offs && beacon) {
int i;
for (i = 0; i < IEEE80211_MAX_CSA_COUNTERS_NUM; i++) {
- u16 csa_off = sdata->csa_counter_offset_beacon[i];
+ u16 csa_off = beacon->csa_counter_offsets[i];
if (!csa_off)
continue;
--
1.8.5.3
--
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