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mac80211: ibss: use beacon_data struct for beacon and probe response
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Instead of having an SKB all the time, use a beacon_data struct
with just the information required. This also allows removing a
synchronize_rcu() and using kfree_rcu() instead.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Johannes Berg committed Mar 25, 2013
1 parent 1852d40 commit c3ffeab
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Showing 3 changed files with 70 additions and 71 deletions.
131 changes: 64 additions & 67 deletions net/mac80211/ibss.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,14 +44,15 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
struct ieee80211_local *local = sdata->local;
int rates, i;
struct sk_buff *skb;
struct ieee80211_mgmt *mgmt;
u8 *pos;
struct ieee80211_supported_band *sband;
struct cfg80211_bss *bss;
u32 bss_change;
u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
struct cfg80211_chan_def chandef;
struct beacon_data *presp;
int frame_len;

lockdep_assert_held(&ifibss->mtx);

Expand All @@ -72,13 +73,11 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
BSS_CHANGED_BEACON_ENABLED);
}

skb = ifibss->skb;
RCU_INIT_POINTER(ifibss->presp, NULL);
synchronize_rcu();
skb->data = skb->head;
skb->len = 0;
skb_reset_tail_pointer(skb);
skb_reserve(skb, sdata->local->hw.extra_tx_headroom);
presp = rcu_dereference_protected(ifibss->presp,
lockdep_is_held(&ifibss->mtx));
rcu_assign_pointer(ifibss->presp, NULL);
if (presp)
kfree_rcu(presp, rcu_head);

sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;

Expand All @@ -101,19 +100,24 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,

sband = local->hw.wiphy->bands[chan->band];

/* build supported rates array */
pos = supp_rates;
for (i = 0; i < sband->n_bitrates; i++) {
int rate = sband->bitrates[i].bitrate;
u8 basic = 0;
if (basic_rates & BIT(i))
basic = 0x80;
*pos++ = basic | (u8) (rate / 5);
}

/* Build IBSS probe response */
mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
frame_len = sizeof(struct ieee80211_hdr_3addr) +
12 /* struct ieee80211_mgmt.u.beacon */ +
2 + IEEE80211_MAX_SSID_LEN /* max SSID */ +
2 + 8 /* max Supported Rates */ +
3 /* max DS params */ +
4 /* IBSS params */ +
2 + (IEEE80211_MAX_SUPP_RATES - 8) +
2 + sizeof(struct ieee80211_ht_cap) +
2 + sizeof(struct ieee80211_ht_operation) +
ifibss->ie_len;
presp = kzalloc(sizeof(*presp) + frame_len, GFP_KERNEL);
if (!presp)
return;

presp->head = (void *)(presp + 1);

mgmt = (void *) presp->head;
mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_PROBE_RESP);
eth_broadcast_addr(mgmt->da);
Expand All @@ -123,51 +127,56 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
mgmt->u.beacon.capab_info = cpu_to_le16(capability);

pos = skb_put(skb, 2 + ifibss->ssid_len);
pos = (u8 *)mgmt + offsetof(struct ieee80211_mgmt, u.beacon.variable);

*pos++ = WLAN_EID_SSID;
*pos++ = ifibss->ssid_len;
memcpy(pos, ifibss->ssid, ifibss->ssid_len);
pos += ifibss->ssid_len;

rates = sband->n_bitrates;
if (rates > 8)
rates = 8;
pos = skb_put(skb, 2 + rates);
rates = min_t(int, 8, sband->n_bitrates);
*pos++ = WLAN_EID_SUPP_RATES;
*pos++ = rates;
memcpy(pos, supp_rates, rates);
for (i = 0; i < rates; i++) {
int rate = sband->bitrates[i].bitrate;
u8 basic = 0;
if (basic_rates & BIT(i))
basic = 0x80;
*pos++ = basic | (u8) (rate / 5);
}

if (sband->band == IEEE80211_BAND_2GHZ) {
pos = skb_put(skb, 2 + 1);
*pos++ = WLAN_EID_DS_PARAMS;
*pos++ = 1;
*pos++ = ieee80211_frequency_to_channel(chan->center_freq);
}

pos = skb_put(skb, 2 + 2);
*pos++ = WLAN_EID_IBSS_PARAMS;
*pos++ = 2;
/* FIX: set ATIM window based on scan results */
*pos++ = 0;
*pos++ = 0;

if (sband->n_bitrates > 8) {
rates = sband->n_bitrates - 8;
pos = skb_put(skb, 2 + rates);
*pos++ = WLAN_EID_EXT_SUPP_RATES;
*pos++ = rates;
memcpy(pos, &supp_rates[8], rates);
*pos++ = sband->n_bitrates - 8;
for (i = 8; i < sband->n_bitrates; i++) {
int rate = sband->bitrates[i].bitrate;
u8 basic = 0;
if (basic_rates & BIT(i))
basic = 0x80;
*pos++ = basic | (u8) (rate / 5);
}
}

if (ifibss->ie_len)
memcpy(skb_put(skb, ifibss->ie_len),
ifibss->ie, ifibss->ie_len);
if (ifibss->ie_len) {
memcpy(pos, ifibss->ie, ifibss->ie_len);
pos += ifibss->ie_len;
}

/* add HT capability and information IEs */
if (chandef.width != NL80211_CHAN_WIDTH_20_NOHT &&
sband->ht_cap.ht_supported) {
pos = skb_put(skb, 4 +
sizeof(struct ieee80211_ht_cap) +
sizeof(struct ieee80211_ht_operation));
pos = ieee80211_ie_build_ht_cap(pos, &sband->ht_cap,
sband->ht_cap.cap);
/*
Expand All @@ -180,7 +189,6 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
}

if (local->hw.queues >= IEEE80211_NUM_ACS) {
pos = skb_put(skb, 9);
*pos++ = WLAN_EID_VENDOR_SPECIFIC;
*pos++ = 7; /* len */
*pos++ = 0x00; /* Microsoft OUI 00:50:F2 */
Expand All @@ -192,7 +200,11 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
*pos++ = 0; /* U-APSD no in use */
}

rcu_assign_pointer(ifibss->presp, skb);
presp->head_len = pos - presp->head;
if (WARN_ON(presp->head_len > frame_len))
return;

rcu_assign_pointer(ifibss->presp, presp);

sdata->vif.bss_conf.enable_beacon = true;
sdata->vif.bss_conf.beacon_int = beacon_int;
Expand Down Expand Up @@ -230,7 +242,7 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));

bss = cfg80211_inform_bss_frame(local->hw.wiphy, chan,
mgmt, skb->len, 0, GFP_KERNEL);
mgmt, presp->head_len, 0, GFP_KERNEL);
cfg80211_put_bss(local->hw.wiphy, bss);
netif_carrier_on(sdata->dev);
cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
Expand Down Expand Up @@ -825,8 +837,7 @@ static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
struct ieee80211_local *local = sdata->local;
int tx_last_beacon, len = req->len;
struct sk_buff *skb;
struct ieee80211_mgmt *resp;
struct sk_buff *presp;
struct beacon_data *presp;
u8 *pos, *end;

lockdep_assert_held(&ifibss->mtx);
Expand Down Expand Up @@ -867,13 +878,15 @@ static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
}

/* Reply with ProbeResp */
skb = skb_copy(presp, GFP_KERNEL);
skb = dev_alloc_skb(local->tx_headroom + presp->head_len);
if (!skb)
return;

resp = (struct ieee80211_mgmt *) skb->data;
memcpy(resp->da, mgmt->sa, ETH_ALEN);
ibss_dbg(sdata, "Sending ProbeResp to %pM\n", resp->da);
skb_reserve(skb, local->tx_headroom);
memcpy(skb_put(skb, presp->head_len), presp->head, presp->head_len);

memcpy(((struct ieee80211_mgmt *) skb->data)->da, mgmt->sa, ETH_ALEN);
ibss_dbg(sdata, "Sending ProbeResp to %pM\n", mgmt->sa);
IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
ieee80211_tx_skb(sdata, skb);
}
Expand Down Expand Up @@ -1023,23 +1036,8 @@ void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
struct cfg80211_ibss_params *params)
{
struct sk_buff *skb;
u32 changed = 0;

skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
sizeof(struct ieee80211_hdr_3addr) +
12 /* struct ieee80211_mgmt.u.beacon */ +
2 + IEEE80211_MAX_SSID_LEN /* max SSID */ +
2 + 8 /* max Supported Rates */ +
3 /* max DS params */ +
4 /* IBSS params */ +
2 + (IEEE80211_MAX_SUPP_RATES - 8) +
2 + sizeof(struct ieee80211_ht_cap) +
2 + sizeof(struct ieee80211_ht_operation) +
params->ie_len);
if (!skb)
return -ENOMEM;

mutex_lock(&sdata->u.ibss.mtx);

if (params->bssid) {
Expand Down Expand Up @@ -1068,7 +1066,6 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
sdata->u.ibss.ie_len = params->ie_len;
}

sdata->u.ibss.skb = skb;
sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
sdata->u.ibss.ibss_join_req = jiffies;

Expand Down Expand Up @@ -1104,13 +1101,13 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,

int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
{
struct sk_buff *skb;
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
struct ieee80211_local *local = sdata->local;
struct cfg80211_bss *cbss;
u16 capability;
int active_ibss;
struct sta_info *sta;
struct beacon_data *presp;

mutex_lock(&sdata->u.ibss.mtx);

Expand Down Expand Up @@ -1156,8 +1153,8 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)

/* remove beacon */
kfree(sdata->u.ibss.ie);
skb = rcu_dereference_protected(sdata->u.ibss.presp,
lockdep_is_held(&sdata->u.ibss.mtx));
presp = rcu_dereference_protected(ifibss->presp,
lockdep_is_held(&sdata->u.ibss.mtx));
RCU_INIT_POINTER(sdata->u.ibss.presp, NULL);
sdata->vif.bss_conf.ibss_joined = false;
sdata->vif.bss_conf.ibss_creator = false;
Expand All @@ -1166,7 +1163,7 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |
BSS_CHANGED_IBSS);
synchronize_rcu();
kfree_skb(skb);
kfree(presp);

skb_queue_purge(&sdata->skb_queue);

Expand Down
3 changes: 1 addition & 2 deletions net/mac80211/ieee80211_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -508,8 +508,7 @@ struct ieee80211_if_ibss {

unsigned long ibss_join_req;
/* probe response/beacon for IBSS */
struct sk_buff __rcu *presp;
struct sk_buff *skb;
struct beacon_data __rcu *presp;

spinlock_t incomplete_lock;
struct list_head incomplete_stations;
Expand Down
7 changes: 5 additions & 2 deletions net/mac80211/tx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2442,14 +2442,17 @@ struct sk_buff *ieee80211_beacon_get_tim(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 sk_buff *presp = rcu_dereference(ifibss->presp);
struct beacon_data *presp = rcu_dereference(ifibss->presp);

if (!presp)
goto out;

skb = skb_copy(presp, GFP_ATOMIC);
skb = dev_alloc_skb(local->tx_headroom + presp->head_len);
if (!skb)
goto out;
skb_reserve(skb, local->tx_headroom);
memcpy(skb_put(skb, presp->head_len), presp->head,
presp->head_len);

hdr = (struct ieee80211_hdr *) skb->data;
hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
Expand Down

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