[PATCH v2 18/22] mac80211: receive and process S1G beacons

Thomas Pedersen
2020-08-31T20:56:49Z

S1G beacons are 802.11 Extension Frames, so the fixed
header part differs from regular beacons.

Add a handler to process S1G beacons and abstract out the
fetching of BSSID and element start locations in the
beacon body handler.

Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
---
net/mac80211/ieee80211_i.h | 4 ++
net/mac80211/iface.c | 5 +++
net/mac80211/mlme.c | 87 +++++++++++++++++++++++++++++---------
net/mac80211/rx.c | 84 ++++++++++++++++--------------------
net/mac80211/util.c | 52 +++++++++++++++++++++++
5 files changed, 164 insertions(+), 68 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index cf78e356b25d..9847cfa0e08c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1649,6 +1649,8 @@ int ieee80211_set_arp_filter(struct ieee80211_sub_if_data *sdata);
void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata);
void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb);
+void ieee80211_sta_rx_queued_ext(struct ieee80211_sub_if_data *sdata,
+ struct sk_buff *skb);
void ieee80211_sta_reset_beacon_monitor(struct ieee80211_sub_if_data *sdata);
void ieee80211_sta_reset_conn_monitor(struct ieee80211_sub_if_data *sdata);
void ieee80211_mgd_stop(struct ieee80211_sub_if_data *sdata);
@@ -2294,6 +2296,8 @@ void ieee80211_tdls_handle_disconnect(struct ieee80211_sub_if_data *sdata,
const u8 *peer, u16 reason);
const char *ieee80211_get_reason_code_string(u16 reason_code);
__le16 ieee80211_encode_usf(int val);
+u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+ enum nl80211_iftype type);

extern const struct ethtool_ops ieee80211_ethtool_ops;

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 9740ae8fa697..1369f6e575d7 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1379,6 +1379,11 @@ static void ieee80211_iface_work(struct work_struct *work)
WARN_ON(1);
break;
}
+ } else if (ieee80211_is_ext(mgmt->frame_control)) {
+ if (sdata->vif.type == NL80211_IFTYPE_STATION)
+ ieee80211_sta_rx_queued_ext(sdata, skb);
+ else
+ WARN_ON(1);
} else if (ieee80211_is_data_qos(mgmt->frame_control)) {
struct ieee80211_hdr *hdr = (void *)mgmt;
/*
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 6a62a221b89e..9a26ef99cef9 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1604,6 +1604,9 @@ static u32 ieee80211_handle_pwr_constr(struct ieee80211_sub_if_data *sdata,
int new_ap_level;
__le16 capab = mgmt->u.probe_resp.capab_info;

+ if (ieee80211_is_s1g_beacon(mgmt->frame_control))
+ return 0; /* TODO */
+
if (country_ie &&
(capab & cpu_to_le16(WLAN_CAPABILITY_SPECTRUM_MGMT) ||
capab & cpu_to_le16(WLAN_CAPABILITY_RADIO_MEASURE))) {
@@ -2450,7 +2453,8 @@ void ieee80211_sta_rx_notify(struct ieee80211_sub_if_data *sdata,
* data idle periods for sending the periodic probe request to the
* AP we're connected to.
*/
- if (is_multicast_ether_addr(hdr->addr1))
+ if (is_multicast_ether_addr(hdr->addr1) ||
+ ieee80211_is_s1g_beacon(hdr->frame_control))
return;

ieee80211_sta_reset_conn_monitor(sdata);
@@ -3919,12 +3923,13 @@ static bool ieee80211_rx_our_beacon(const u8 *tx_bssid,
return ether_addr_equal(tx_bssid, bss->transmitted_bss->bssid);
}

-static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
- struct ieee80211_mgmt *mgmt, size_t len,
- struct ieee80211_rx_status *rx_status)
+static void ieee80211_rx_beacon(struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_hdr *hdr, size_t len,
+ struct ieee80211_rx_status *rx_status)
{
struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf;
+ struct ieee80211_mgmt *mgmt = (void *) hdr;
size_t baselen;
struct ieee802_11_elems elems;
struct ieee80211_local *local = sdata->local;
@@ -3934,14 +3939,24 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
u32 changed = 0;
bool erp_valid;
u8 erp_value = 0;
- u32 ncrc;
- u8 *bssid;
+ u32 ncrc = 0;
+ u8 *bssid, *variable = mgmt->u.beacon.variable;
u8 deauth_buf[IEEE80211_DEAUTH_FRAME_LEN];

sdata_assert_lock(sdata);

/* Process beacon from the current BSS */
- baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
+ bssid = ieee80211_get_bssid(hdr, len, sdata->vif.type);
+ if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
+ struct ieee80211_ext *ext = (void *) mgmt;
+
+ if (ieee80211_is_s1g_short_beacon(ext->frame_control))
+ variable = ext->u.s1g_short_beacon.variable;
+ else
+ variable = ext->u.s1g_beacon.variable;
+ }
+
+ baselen = (u8 *) variable - (u8 *) mgmt;
if (baselen > len)
return;

@@ -3961,10 +3976,10 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
rcu_read_unlock();

if (ifmgd->assoc_data && ifmgd->assoc_data->need_beacon &&
- ieee80211_rx_our_beacon(mgmt->bssid, ifmgd->assoc_data->bss)) {
- ieee802_11_parse_elems(mgmt->u.beacon.variable,
+ ieee80211_rx_our_beacon(bssid, ifmgd->assoc_data->bss)) {
+ ieee802_11_parse_elems(variable,
len - baselen, false, &elems,
- mgmt->bssid,
+ bssid,
ifmgd->assoc_data->bss->bssid);

ieee80211_rx_bss_info(sdata, mgmt, len, rx_status);
@@ -3997,7 +4012,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
}

if (!ifmgd->associated ||
- !ieee80211_rx_our_beacon(mgmt->bssid, ifmgd->associated))
+ !ieee80211_rx_our_beacon(bssid, ifmgd->associated))
return;
bssid = ifmgd->associated->bssid;

@@ -4017,8 +4032,14 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
*/
ieee80211_sta_reset_beacon_monitor(sdata);

- ncrc = crc32_be(0, (void *)&mgmt->u.beacon.beacon_int, 4);
- ncrc = ieee802_11_parse_elems_crc(mgmt->u.beacon.variable,
+ /* TODO: CRC urrently not calculated on S1G Beacon Compatibility
+ * element (which carries the beacon interval). Don't forget to add a
+ * bit to care_about_ies[] above if mac80211 is interested in a
+ * changing S1G element.
+ */
+ if (!ieee80211_is_s1g_beacon(hdr->frame_control))
+ ncrc = crc32_be(0, (void *)&mgmt->u.beacon.beacon_int, 4);
+ ncrc = ieee802_11_parse_elems_crc(variable,
len - baselen, false, &elems,
care_about_ies, ncrc,
mgmt->bssid, bssid);
@@ -4052,7 +4073,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
struct ieee80211_p2p_noa_attr noa = {};
int ret;

- ret = cfg80211_get_p2p_attr(mgmt->u.beacon.variable,
+ ret = cfg80211_get_p2p_attr(variable,
len - baselen,
IEEE80211_P2P_ATTR_ABSENCE_NOTICE,
(u8 *) &noa, sizeof(noa));
@@ -4088,7 +4109,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
* the driver will use them. The synchronized view is currently
* guaranteed only in certain callbacks.
*/
- if (ieee80211_hw_check(&local->hw, TIMING_BEACON_ONLY)) {
+ if (ieee80211_hw_check(&local->hw, TIMING_BEACON_ONLY) &&
+ !ieee80211_is_s1g_beacon(hdr->frame_control)) {
sdata->vif.bss_conf.sync_tsf =
le64_to_cpu(mgmt->u.beacon.timestamp);
sdata->vif.bss_conf.sync_device_ts =
@@ -4096,7 +4118,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
sdata->vif.bss_conf.sync_dtim_count = elems.dtim_count;
}

- if (ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid)
+ if ((ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid) ||
+ ieee80211_is_s1g_short_beacon(mgmt->frame_control))
return;
ifmgd->beacon_crc = ncrc;
ifmgd->beacon_crc_valid = true;
@@ -4137,9 +4160,12 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
} else {
erp_valid = false;
}
- changed |= ieee80211_handle_bss_capability(sdata,
- le16_to_cpu(mgmt->u.beacon.capab_info),
- erp_valid, erp_value);
+
+ if (!ieee80211_is_s1g_beacon(hdr->frame_control)) {
+ changed |= ieee80211_handle_bss_capability(sdata,
+ le16_to_cpu(mgmt->u.beacon.capab_info),
+ erp_valid, erp_value);
+ }

mutex_lock(&local->sta_mtx);
sta = sta_info_get(sdata, bssid);
@@ -4177,6 +4203,26 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
ieee80211_bss_info_change_notify(sdata, changed);
}

+void ieee80211_sta_rx_queued_ext(struct ieee80211_sub_if_data *sdata,
+ struct sk_buff *skb)
+{
+ struct ieee80211_rx_status *rx_status;
+ struct ieee80211_hdr *hdr;
+ u16 fc;
+
+ rx_status = (struct ieee80211_rx_status *) skb->cb;
+ hdr = (struct ieee80211_hdr *) skb->data;
+ fc = le16_to_cpu(hdr->frame_control);
+
+ sdata_lock(sdata);
+ switch (fc & IEEE80211_FCTL_STYPE) {
+ case IEEE80211_STYPE_S1G_BEACON:
+ ieee80211_rx_beacon(sdata, hdr, skb->len, rx_status);
+ break;
+ }
+ sdata_unlock(sdata);
+}
+
void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb)
{
@@ -4194,7 +4240,8 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,

switch (fc & IEEE80211_FCTL_STYPE) {
case IEEE80211_STYPE_BEACON:
- ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len, rx_status);
+ ieee80211_rx_beacon(sdata, (struct ieee80211_hdr *) mgmt,
+ skb->len, rx_status);
break;
case IEEE80211_STYPE_PROBE_RESP:
ieee80211_rx_mgmt_probe_resp(sdata, skb);
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 5b92f56682e2..e1291898bde8 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -42,51 +42,6 @@ static inline void ieee80211_rx_stats(struct net_device *dev, u32 len)
u64_stats_update_end(&tstats->syncp);
}

-static u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
- enum nl80211_iftype type)
-{
- __le16 fc = hdr->frame_control;
-
- if (ieee80211_is_data(fc)) {
- if (len < 24) /* drop incorrect hdr len (data) */
- return NULL;
-
- if (ieee80211_has_a4(fc))
- return NULL;
- if (ieee80211_has_tods(fc))
- return hdr->addr1;
- if (ieee80211_has_fromds(fc))
- return hdr->addr2;
-
- return hdr->addr3;
- }
-
- if (ieee80211_is_mgmt(fc)) {
- if (len < 24) /* drop incorrect hdr len (mgmt) */
- return NULL;
- return hdr->addr3;
- }
-
- if (ieee80211_is_ctl(fc)) {
- if (ieee80211_is_pspoll(fc))
- return hdr->addr1;
-
- if (ieee80211_is_back_req(fc)) {
- switch (type) {
- case NL80211_IFTYPE_STATION:
- return hdr->addr2;
- case NL80211_IFTYPE_AP:
- case NL80211_IFTYPE_AP_VLAN:
- return hdr->addr1;
- default:
- break; /* fall through to the return */
- }
- }
- }
-
- return NULL;
-}
-
/*
* monitor mode reception
*
@@ -1801,7 +1756,8 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
}
} else if (rx->sdata->vif.type == NL80211_IFTYPE_OCB) {
sta->rx_stats.last_rx = jiffies;
- } else if (!is_multicast_ether_addr(hdr->addr1)) {
+ } else if (!ieee80211_is_s1g_beacon(hdr->frame_control) &&
+ is_multicast_ether_addr(hdr->addr1)) {
/*
* Mesh beacons will update last_rx when if they are found to
* match the current local configuration when processed.
@@ -1839,6 +1795,9 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
}
}

+ if (ieee80211_is_s1g_beacon(hdr->frame_control))
+ return RX_CONTINUE;
+
/*
* Change STA power saving mode only at the end of a frame
* exchange sequence, and only for a data or management
@@ -1949,6 +1908,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
__le16 fc;
const struct ieee80211_cipher_scheme *cs = NULL;

+ if (ieee80211_is_ext(hdr->frame_control))
+ return RX_CONTINUE;
+
/*
* Key selection 101
*
@@ -2257,7 +2219,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
hdr = (struct ieee80211_hdr *)rx->skb->data;
fc = hdr->frame_control;

- if (ieee80211_is_ctl(fc))
+ if (ieee80211_is_ctl(fc) || ieee80211_is_ext(fc))
return RX_CONTINUE;

sc = le16_to_cpu(hdr->seq_ctrl);
@@ -3131,6 +3093,9 @@ ieee80211_rx_h_mgmt_check(struct ieee80211_rx_data *rx)
struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);

+ if (ieee80211_is_s1g_beacon(mgmt->frame_control))
+ return RX_CONTINUE;
+
/*
* From here on, look only at management frames.
* Data and control frames are already handled,
@@ -3597,6 +3562,27 @@ ieee80211_rx_h_action_return(struct ieee80211_rx_data *rx)
return RX_QUEUED;
}

+static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_ext(struct ieee80211_rx_data *rx)
+{
+ struct ieee80211_sub_if_data *sdata = rx->sdata;
+ struct ieee80211_hdr *hdr = (void *)rx->skb->data;
+
+ if (!ieee80211_is_ext(hdr->frame_control))
+ return RX_CONTINUE;
+
+ if (sdata->vif.type != NL80211_IFTYPE_STATION)
+ return RX_DROP_MONITOR;
+
+ /* for now only beacons are ext, so queue them */
+ skb_queue_tail(&sdata->skb_queue, rx->skb);
+ ieee80211_queue_work(&rx->local->hw, &sdata->work);
+ if (rx->sta)
+ rx->sta->rx_stats.packets++;
+
+ return RX_QUEUED;
+}
+
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
{
@@ -3816,6 +3802,7 @@ static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
CALL_RXH(ieee80211_rx_h_userspace_mgmt);
CALL_RXH(ieee80211_rx_h_action_post_userspace);
CALL_RXH(ieee80211_rx_h_action_return);
+ CALL_RXH(ieee80211_rx_h_ext);
CALL_RXH(ieee80211_rx_h_mgmt);

rxh_next:
@@ -3982,7 +3969,8 @@ static bool ieee80211_accept_frame(struct ieee80211_rx_data *rx)
struct ieee80211_hdr *hdr = (void *)skb->data;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
u8 *bssid = ieee80211_get_bssid(hdr, skb->len, sdata->vif.type);
- bool multicast = is_multicast_ether_addr(hdr->addr1);
+ bool multicast = is_multicast_ether_addr(hdr->addr1) ||
+ ieee80211_is_s1g_beacon(hdr->frame_control);

switch (sdata->vif.type) {
case NL80211_IFTYPE_STATION:
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 57c6f8bd2bdf..31845e392759 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -45,6 +45,58 @@ struct ieee80211_hw *wiphy_to_ieee80211_hw(struct wiphy *wiphy)
}
EXPORT_SYMBOL(wiphy_to_ieee80211_hw);

+u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+ enum nl80211_iftype type)
+{
+ __le16 fc = hdr->frame_control;
+
+ if (ieee80211_is_data(fc)) {
+ if (len < 24) /* drop incorrect hdr len (data) */
+ return NULL;
+
+ if (ieee80211_has_a4(fc))
+ return NULL;
+ if (ieee80211_has_tods(fc))
+ return hdr->addr1;
+ if (ieee80211_has_fromds(fc))
+ return hdr->addr2;
+
+ return hdr->addr3;
+ }
+
+ if (ieee80211_is_s1g_beacon(fc)) {
+ struct ieee80211_ext *ext = (void *) hdr;
+
+ return ext->u.s1g_beacon.sa;
+ }
+
+ if (ieee80211_is_mgmt(fc)) {
+ if (len < 24) /* drop incorrect hdr len (mgmt) */
+ return NULL;
+ return hdr->addr3;
+ }
+
+ if (ieee80211_is_ctl(fc)) {
+ if (ieee80211_is_pspoll(fc))
+ return hdr->addr1;
+
+ if (ieee80211_is_back_req(fc)) {
+ switch (type) {
+ case NL80211_IFTYPE_STATION:
+ return hdr->addr2;
+ case NL80211_IFTYPE_AP:
+ case NL80211_IFTYPE_AP_VLAN:
+ return hdr->addr1;
+ default:
+ break; /* fall through to the return */
+ }
+ }
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(ieee80211_get_bssid);
+
void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb;
--
2.20.1