Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1237 insertions, 0 deletions

diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
new file mode 100644
index 000000000..711c3377f
--- /dev/null
+++ b/net/mac80211/mesh_plink.c
@@ -0,0 +1,1237 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2008, 2009 open80211s Ltd.
+ * Copyright (C) 2019, 2021-2022 Intel Corporation
+ * Author:     Luis Carlos Cobo <luisca@cozybit.com>
+ */
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/random.h>
+#include <linux/rculist.h>
+
+#include "ieee80211_i.h"
+#include "rate.h"
+#include "mesh.h"
+
+#define PLINK_CNF_AID(mgmt) ((mgmt)->u.action.u.self_prot.variable + 2)
+#define PLINK_GET_LLID(p) (p + 2)
+#define PLINK_GET_PLID(p) (p + 4)
+
+#define mod_plink_timer(s, t) (mod_timer(&s->mesh->plink_timer, \
+				jiffies + msecs_to_jiffies(t)))
+
+enum plink_event {
+	PLINK_UNDEFINED,
+	OPN_ACPT,
+	OPN_RJCT,
+	OPN_IGNR,
+	CNF_ACPT,
+	CNF_RJCT,
+	CNF_IGNR,
+	CLS_ACPT,
+	CLS_IGNR
+};
+
+static const char * const mplstates[] = {
+	[NL80211_PLINK_LISTEN] = "LISTEN",
+	[NL80211_PLINK_OPN_SNT] = "OPN-SNT",
+	[NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
+	[NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
+	[NL80211_PLINK_ESTAB] = "ESTAB",
+	[NL80211_PLINK_HOLDING] = "HOLDING",
+	[NL80211_PLINK_BLOCKED] = "BLOCKED"
+};
+
+static const char * const mplevents[] = {
+	[PLINK_UNDEFINED] = "NONE",
+	[OPN_ACPT] = "OPN_ACPT",
+	[OPN_RJCT] = "OPN_RJCT",
+	[OPN_IGNR] = "OPN_IGNR",
+	[CNF_ACPT] = "CNF_ACPT",
+	[CNF_RJCT] = "CNF_RJCT",
+	[CNF_IGNR] = "CNF_IGNR",
+	[CLS_ACPT] = "CLS_ACPT",
+	[CLS_IGNR] = "CLS_IGNR"
+};
+
+/* We only need a valid sta if user configured a minimum rssi_threshold. */
+static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
+				 struct sta_info *sta)
+{
+	s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
+	return rssi_threshold == 0 ||
+	       (sta &&
+		(s8)-ewma_signal_read(&sta->deflink.rx_stats_avg.signal) >
+		rssi_threshold);
+}
+
+/**
+ * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
+ *
+ * @sta: mesh peer link to restart
+ *
+ * Locking: this function must be called holding sta->mesh->plink_lock
+ */
+static inline void mesh_plink_fsm_restart(struct sta_info *sta)
+{
+	lockdep_assert_held(&sta->mesh->plink_lock);
+	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
+	sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
+	sta->mesh->plink_retries = 0;
+}
+
+/*
+ * mesh_set_short_slot_time - enable / disable ERP short slot time.
+ *
+ * The standard indirectly mandates mesh STAs to turn off short slot time by
+ * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
+ * can't be sneaky about it. Enable short slot time if all mesh STAs in the
+ * MBSS support ERP rates.
+ *
+ * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
+ */
+static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_supported_band *sband;
+	struct sta_info *sta;
+	u32 erp_rates = 0, changed = 0;
+	int i;
+	bool short_slot = false;
+
+	sband = ieee80211_get_sband(sdata);
+	if (!sband)
+		return changed;
+
+	if (sband->band == NL80211_BAND_5GHZ) {
+		/* (IEEE 802.11-2012 19.4.5) */
+		short_slot = true;
+		goto out;
+	} else if (sband->band != NL80211_BAND_2GHZ) {
+		goto out;
+	}
+
+	for (i = 0; i < sband->n_bitrates; i++)
+		if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
+			erp_rates |= BIT(i);
+
+	if (!erp_rates)
+		goto out;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sta, &local->sta_list, list) {
+		if (sdata != sta->sdata ||
+		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
+			continue;
+
+		short_slot = false;
+		if (erp_rates & sta->sta.deflink.supp_rates[sband->band])
+			short_slot = true;
+		 else
+			break;
+	}
+	rcu_read_unlock();
+
+out:
+	if (sdata->vif.bss_conf.use_short_slot != short_slot) {
+		sdata->vif.bss_conf.use_short_slot = short_slot;
+		changed = BSS_CHANGED_ERP_SLOT;
+		mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
+			sdata->vif.addr, short_slot);
+	}
+	return changed;
+}
+
+/**
+ * mesh_set_ht_prot_mode - set correct HT protection mode
+ * @sdata: the (mesh) interface to handle
+ *
+ * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
+ * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
+ * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
+ * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
+ * is selected if all peers in our 20/40MHz MBSS support HT and at least one
+ * HT20 peer is present. Otherwise no-protection mode is selected.
+ */
+static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct sta_info *sta;
+	u16 ht_opmode;
+	bool non_ht_sta = false, ht20_sta = false;
+
+	switch (sdata->vif.bss_conf.chandef.width) {
+	case NL80211_CHAN_WIDTH_20_NOHT:
+	case NL80211_CHAN_WIDTH_5:
+	case NL80211_CHAN_WIDTH_10:
+		return 0;
+	default:
+		break;
+	}
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sta, &local->sta_list, list) {
+		if (sdata != sta->sdata ||
+		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
+			continue;
+
+		if (sta->sta.deflink.bandwidth > IEEE80211_STA_RX_BW_20)
+			continue;
+
+		if (!sta->sta.deflink.ht_cap.ht_supported) {
+			mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
+				       sta->sta.addr);
+			non_ht_sta = true;
+			break;
+		}
+
+		mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
+		ht20_sta = true;
+	}
+	rcu_read_unlock();
+
+	if (non_ht_sta)
+		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
+	else if (ht20_sta &&
+		 sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
+		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
+	else
+		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
+
+	if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
+		return 0;
+
+	sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
+	sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
+	mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
+	return BSS_CHANGED_HT;
+}
+
+static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
+			       struct sta_info *sta,
+			       enum ieee80211_self_protected_actioncode action,
+			       u8 *da, u16 llid, u16 plid, u16 reason)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct sk_buff *skb;
+	struct ieee80211_tx_info *info;
+	struct ieee80211_mgmt *mgmt;
+	bool include_plid = false;
+	u16 peering_proto = 0;
+	u8 *pos, ie_len = 4;
+	u8 ie_len_he_cap;
+	int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
+	int err = -ENOMEM;
+
+	ie_len_he_cap = ieee80211_ie_len_he_cap(sdata,
+						NL80211_IFTYPE_MESH_POINT);
+	skb = dev_alloc_skb(local->tx_headroom +
+			    hdr_len +
+			    2 + /* capability info */
+			    2 + /* AID */
+			    2 + 8 + /* supported rates */
+			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
+			    2 + sdata->u.mesh.mesh_id_len +
+			    2 + sizeof(struct ieee80211_meshconf_ie) +
+			    2 + sizeof(struct ieee80211_ht_cap) +
+			    2 + sizeof(struct ieee80211_ht_operation) +
+			    2 + sizeof(struct ieee80211_vht_cap) +
+			    2 + sizeof(struct ieee80211_vht_operation) +
+			    ie_len_he_cap +
+			    2 + 1 + sizeof(struct ieee80211_he_operation) +
+				    sizeof(struct ieee80211_he_6ghz_oper) +
+			    2 + 1 + sizeof(struct ieee80211_he_6ghz_capa) +
+			    2 + 8 + /* peering IE */
+			    sdata->u.mesh.ie_len);
+	if (!skb)
+		return err;
+	info = IEEE80211_SKB_CB(skb);
+	skb_reserve(skb, local->tx_headroom);
+	mgmt = skb_put_zero(skb, hdr_len);
+	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
+					  IEEE80211_STYPE_ACTION);
+	memcpy(mgmt->da, da, ETH_ALEN);
+	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
+	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
+	mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
+	mgmt->u.action.u.self_prot.action_code = action;
+
+	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
+		struct ieee80211_supported_band *sband;
+		enum nl80211_band band;
+
+		sband = ieee80211_get_sband(sdata);
+		if (!sband) {
+			err = -EINVAL;
+			goto free;
+		}
+		band = sband->band;
+
+		/* capability info */
+		pos = skb_put_zero(skb, 2);
+		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
+			/* AID */
+			pos = skb_put(skb, 2);
+			put_unaligned_le16(sta->sta.aid, pos);
+		}
+		if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
+		    ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
+		    mesh_add_rsn_ie(sdata, skb) ||
+		    mesh_add_meshid_ie(sdata, skb) ||
+		    mesh_add_meshconf_ie(sdata, skb))
+			goto free;
+	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
+		info->flags |= IEEE80211_TX_CTL_NO_ACK;
+		if (mesh_add_meshid_ie(sdata, skb))
+			goto free;
+	}
+
+	/* Add Mesh Peering Management element */
+	switch (action) {
+	case WLAN_SP_MESH_PEERING_OPEN:
+		break;
+	case WLAN_SP_MESH_PEERING_CONFIRM:
+		ie_len += 2;
+		include_plid = true;
+		break;
+	case WLAN_SP_MESH_PEERING_CLOSE:
+		if (plid) {
+			ie_len += 2;
+			include_plid = true;
+		}
+		ie_len += 2;	/* reason code */
+		break;
+	default:
+		err = -EINVAL;
+		goto free;
+	}
+
+	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
+		goto free;
+
+	pos = skb_put(skb, 2 + ie_len);
+	*pos++ = WLAN_EID_PEER_MGMT;
+	*pos++ = ie_len;
+	memcpy(pos, &peering_proto, 2);
+	pos += 2;
+	put_unaligned_le16(llid, pos);
+	pos += 2;
+	if (include_plid) {
+		put_unaligned_le16(plid, pos);
+		pos += 2;
+	}
+	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
+		put_unaligned_le16(reason, pos);
+		pos += 2;
+	}
+
+	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
+		if (mesh_add_ht_cap_ie(sdata, skb) ||
+		    mesh_add_ht_oper_ie(sdata, skb) ||
+		    mesh_add_vht_cap_ie(sdata, skb) ||
+		    mesh_add_vht_oper_ie(sdata, skb) ||
+		    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
+		    mesh_add_he_oper_ie(sdata, skb) ||
+		    mesh_add_he_6ghz_cap_ie(sdata, skb))
+			goto free;
+	}
+
+	if (mesh_add_vendor_ies(sdata, skb))
+		goto free;
+
+	ieee80211_tx_skb(sdata, skb);
+	return 0;
+free:
+	kfree_skb(skb);
+	return err;
+}
+
+/**
+ * __mesh_plink_deactivate - deactivate mesh peer link
+ *
+ * @sta: mesh peer link to deactivate
+ *
+ * Mesh paths with this peer as next hop should be flushed
+ * by the caller outside of plink_lock.
+ *
+ * Returns beacon changed flag if the beacon content changed.
+ *
+ * Locking: the caller must hold sta->mesh->plink_lock
+ */
+static u32 __mesh_plink_deactivate(struct sta_info *sta)
+{
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+	u32 changed = 0;
+
+	lockdep_assert_held(&sta->mesh->plink_lock);
+
+	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
+		changed = mesh_plink_dec_estab_count(sdata);
+	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
+
+	ieee80211_mps_sta_status_update(sta);
+	changed |= ieee80211_mps_set_sta_local_pm(sta,
+			NL80211_MESH_POWER_UNKNOWN);
+
+	return changed;
+}
+
+/**
+ * mesh_plink_deactivate - deactivate mesh peer link
+ *
+ * @sta: mesh peer link to deactivate
+ *
+ * All mesh paths with this peer as next hop will be flushed
+ */
+u32 mesh_plink_deactivate(struct sta_info *sta)
+{
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+	u32 changed;
+
+	spin_lock_bh(&sta->mesh->plink_lock);
+	changed = __mesh_plink_deactivate(sta);
+
+	if (!sdata->u.mesh.user_mpm) {
+		sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
+		mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
+				    sta->sta.addr, sta->mesh->llid,
+				    sta->mesh->plid, sta->mesh->reason);
+	}
+	spin_unlock_bh(&sta->mesh->plink_lock);
+	if (!sdata->u.mesh.user_mpm)
+		del_timer_sync(&sta->mesh->plink_timer);
+	mesh_path_flush_by_nexthop(sta);
+
+	/* make sure no readers can access nexthop sta from here on */
+	synchronize_net();
+
+	return changed;
+}
+
+static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
+			       struct sta_info *sta,
+			       struct ieee802_11_elems *elems)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_supported_band *sband;
+	u32 rates, basic_rates = 0, changed = 0;
+	enum ieee80211_sta_rx_bandwidth bw = sta->sta.deflink.bandwidth;
+
+	sband = ieee80211_get_sband(sdata);
+	if (!sband)
+		return;
+
+	rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
+					&basic_rates);
+
+	spin_lock_bh(&sta->mesh->plink_lock);
+	sta->deflink.rx_stats.last_rx = jiffies;
+
+	/* rates and capabilities don't change during peering */
+	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
+	    sta->mesh->processed_beacon)
+		goto out;
+	sta->mesh->processed_beacon = true;
+
+	if (sta->sta.deflink.supp_rates[sband->band] != rates)
+		changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
+	sta->sta.deflink.supp_rates[sband->band] = rates;
+
+	if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
+					      elems->ht_cap_elem,
+					      &sta->deflink))
+		changed |= IEEE80211_RC_BW_CHANGED;
+
+	ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
+					    elems->vht_cap_elem, NULL,
+					    &sta->deflink);
+
+	ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
+					  elems->he_cap_len,
+					  elems->he_6ghz_capa,
+					  &sta->deflink);
+
+	if (bw != sta->sta.deflink.bandwidth)
+		changed |= IEEE80211_RC_BW_CHANGED;
+
+	/* HT peer is operating 20MHz-only */
+	if (elems->ht_operation &&
+	    !(elems->ht_operation->ht_param &
+	      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
+		if (sta->sta.deflink.bandwidth != IEEE80211_STA_RX_BW_20)
+			changed |= IEEE80211_RC_BW_CHANGED;
+		sta->sta.deflink.bandwidth = IEEE80211_STA_RX_BW_20;
+	}
+
+	if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
+		rate_control_rate_init(sta);
+	else
+		rate_control_rate_update(local, sband, sta, 0, changed);
+out:
+	spin_unlock_bh(&sta->mesh->plink_lock);
+}
+
+static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
+{
+	struct sta_info *sta;
+	unsigned long *aid_map;
+	int aid;
+
+	aid_map = bitmap_zalloc(IEEE80211_MAX_AID + 1, GFP_KERNEL);
+	if (!aid_map)
+		return -ENOMEM;
+
+	/* reserve aid 0 for mcast indication */
+	__set_bit(0, aid_map);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
+		__set_bit(sta->sta.aid, aid_map);
+	rcu_read_unlock();
+
+	aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
+	bitmap_free(aid_map);
+
+	if (aid > IEEE80211_MAX_AID)
+		return -ENOBUFS;
+
+	return aid;
+}
+
+static struct sta_info *
+__mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
+{
+	struct sta_info *sta;
+	int aid;
+
+	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
+		return NULL;
+
+	aid = mesh_allocate_aid(sdata);
+	if (aid < 0)
+		return NULL;
+
+	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
+	if (!sta)
+		return NULL;
+
+	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
+	sta->sta.wme = true;
+	sta->sta.aid = aid;
+
+	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
+	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
+	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
+
+	return sta;
+}
+
+static struct sta_info *
+mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
+		    struct ieee802_11_elems *elems,
+		    struct ieee80211_rx_status *rx_status)
+{
+	struct sta_info *sta = NULL;
+
+	/* Userspace handles station allocation */
+	if (sdata->u.mesh.user_mpm ||
+	    sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
+		if (mesh_peer_accepts_plinks(elems) &&
+		    mesh_plink_availables(sdata)) {
+			int sig = 0;
+
+			if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
+				sig = rx_status->signal;
+
+			cfg80211_notify_new_peer_candidate(sdata->dev, addr,
+							   elems->ie_start,
+							   elems->total_len,
+							   sig, GFP_KERNEL);
+		}
+	} else
+		sta = __mesh_sta_info_alloc(sdata, addr);
+
+	return sta;
+}
+
+/*
+ * mesh_sta_info_get - return mesh sta info entry for @addr.
+ *
+ * @sdata: local meshif
+ * @addr: peer's address
+ * @elems: IEs from beacon or mesh peering frame.
+ * @rx_status: rx status for the frame for signal reporting
+ *
+ * Return existing or newly allocated sta_info under RCU read lock.
+ * (re)initialize with given IEs.
+ */
+static struct sta_info *
+mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
+		  u8 *addr, struct ieee802_11_elems *elems,
+		  struct ieee80211_rx_status *rx_status) __acquires(RCU)
+{
+	struct sta_info *sta = NULL;
+
+	rcu_read_lock();
+	sta = sta_info_get(sdata, addr);
+	if (sta) {
+		mesh_sta_info_init(sdata, sta, elems);
+	} else {
+		rcu_read_unlock();
+		/* can't run atomic */
+		sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
+		if (!sta) {
+			rcu_read_lock();
+			return NULL;
+		}
+
+		mesh_sta_info_init(sdata, sta, elems);
+
+		if (sta_info_insert_rcu(sta))
+			return NULL;
+	}
+
+	return sta;
+}
+
+/*
+ * mesh_neighbour_update - update or initialize new mesh neighbor.
+ *
+ * @sdata: local meshif
+ * @addr: peer's address
+ * @elems: IEs from beacon or mesh peering frame
+ * @rx_status: rx status for the frame for signal reporting
+ *
+ * Initiates peering if appropriate.
+ */
+void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
+			   u8 *hw_addr,
+			   struct ieee802_11_elems *elems,
+			   struct ieee80211_rx_status *rx_status)
+{
+	struct sta_info *sta;
+	u32 changed = 0;
+
+	sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
+	if (!sta)
+		goto out;
+
+	sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
+		IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
+
+	if (mesh_peer_accepts_plinks(elems) &&
+	    sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
+	    sdata->u.mesh.accepting_plinks &&
+	    sdata->u.mesh.mshcfg.auto_open_plinks &&
+	    rssi_threshold_check(sdata, sta))
+		changed = mesh_plink_open(sta);
+
+	ieee80211_mps_frame_release(sta, elems);
+out:
+	rcu_read_unlock();
+	ieee80211_mbss_info_change_notify(sdata, changed);
+}
+
+void mesh_plink_timer(struct timer_list *t)
+{
+	struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
+	struct sta_info *sta;
+	u16 reason = 0;
+	struct ieee80211_sub_if_data *sdata;
+	struct mesh_config *mshcfg;
+	enum ieee80211_self_protected_actioncode action = 0;
+
+	/*
+	 * This STA is valid because sta_info_destroy() will
+	 * del_timer_sync() this timer after having made sure
+	 * it cannot be readded (by deleting the plink.)
+	 */
+	sta = mesh->plink_sta;
+
+	if (sta->sdata->local->quiescing)
+		return;
+
+	spin_lock_bh(&sta->mesh->plink_lock);
+
+	/* If a timer fires just before a state transition on another CPU,
+	 * we may have already extended the timeout and changed state by the
+	 * time we've acquired the lock and arrived  here.  In that case,
+	 * skip this timer and wait for the new one.
+	 */
+	if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
+		mpl_dbg(sta->sdata,
+			"Ignoring timer for %pM in state %s (timer adjusted)",
+			sta->sta.addr, mplstates[sta->mesh->plink_state]);
+		spin_unlock_bh(&sta->mesh->plink_lock);
+		return;
+	}
+
+	/* del_timer() and handler may race when entering these states */
+	if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
+	    sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
+		mpl_dbg(sta->sdata,
+			"Ignoring timer for %pM in state %s (timer deleted)",
+			sta->sta.addr, mplstates[sta->mesh->plink_state]);
+		spin_unlock_bh(&sta->mesh->plink_lock);
+		return;
+	}
+
+	mpl_dbg(sta->sdata,
+		"Mesh plink timer for %pM fired on state %s\n",
+		sta->sta.addr, mplstates[sta->mesh->plink_state]);
+	sdata = sta->sdata;
+	mshcfg = &sdata->u.mesh.mshcfg;
+
+	switch (sta->mesh->plink_state) {
+	case NL80211_PLINK_OPN_RCVD:
+	case NL80211_PLINK_OPN_SNT:
+		/* retry timer */
+		if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
+			u32 rand;
+			mpl_dbg(sta->sdata,
+				"Mesh plink for %pM (retry, timeout): %d %d\n",
+				sta->sta.addr, sta->mesh->plink_retries,
+				sta->mesh->plink_timeout);
+			get_random_bytes(&rand, sizeof(u32));
+			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
+					     rand % sta->mesh->plink_timeout;
+			++sta->mesh->plink_retries;
+			mod_plink_timer(sta, sta->mesh->plink_timeout);
+			action = WLAN_SP_MESH_PEERING_OPEN;
+			break;
+		}
+		reason = WLAN_REASON_MESH_MAX_RETRIES;
+		fallthrough;
+	case NL80211_PLINK_CNF_RCVD:
+		/* confirm timer */
+		if (!reason)
+			reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
+		sta->mesh->plink_state = NL80211_PLINK_HOLDING;
+		mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
+		action = WLAN_SP_MESH_PEERING_CLOSE;
+		break;
+	case NL80211_PLINK_HOLDING:
+		/* holding timer */
+		del_timer(&sta->mesh->plink_timer);
+		mesh_plink_fsm_restart(sta);
+		break;
+	default:
+		break;
+	}
+	spin_unlock_bh(&sta->mesh->plink_lock);
+	if (action)
+		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
+				    sta->mesh->llid, sta->mesh->plid, reason);
+}
+
+static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
+{
+	sta->mesh->plink_timeout = timeout;
+	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
+}
+
+static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
+			u16 llid)
+{
+	struct ieee80211_local *local = sdata->local;
+	bool in_use = false;
+	struct sta_info *sta;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sta, &local->sta_list, list) {
+		if (sdata != sta->sdata)
+			continue;
+
+		if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
+			in_use = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return in_use;
+}
+
+static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
+{
+	u16 llid;
+
+	do {
+		get_random_bytes(&llid, sizeof(llid));
+	} while (llid_in_use(sdata, llid));
+
+	return llid;
+}
+
+u32 mesh_plink_open(struct sta_info *sta)
+{
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+	u32 changed;
+
+	if (!test_sta_flag(sta, WLAN_STA_AUTH))
+		return 0;
+
+	spin_lock_bh(&sta->mesh->plink_lock);
+	sta->mesh->llid = mesh_get_new_llid(sdata);
+	if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
+	    sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
+		spin_unlock_bh(&sta->mesh->plink_lock);
+		return 0;
+	}
+	sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
+	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
+	spin_unlock_bh(&sta->mesh->plink_lock);
+	mpl_dbg(sdata,
+		"Mesh plink: starting establishment with %pM\n",
+		sta->sta.addr);
+
+	/* set the non-peer mode to active during peering */
+	changed = ieee80211_mps_local_status_update(sdata);
+
+	mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
+			    sta->sta.addr, sta->mesh->llid, 0, 0);
+	return changed;
+}
+
+u32 mesh_plink_block(struct sta_info *sta)
+{
+	u32 changed;
+
+	spin_lock_bh(&sta->mesh->plink_lock);
+	changed = __mesh_plink_deactivate(sta);
+	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
+	spin_unlock_bh(&sta->mesh->plink_lock);
+	mesh_path_flush_by_nexthop(sta);
+
+	return changed;
+}
+
+static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
+			     struct sta_info *sta,
+			     enum plink_event event)
+{
+	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
+	u16 reason = (event == CLS_ACPT) ?
+		     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
+
+	sta->mesh->reason = reason;
+	sta->mesh->plink_state = NL80211_PLINK_HOLDING;
+	mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
+}
+
+static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
+				struct sta_info *sta)
+{
+	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
+	u32 changed = 0;
+
+	del_timer(&sta->mesh->plink_timer);
+	sta->mesh->plink_state = NL80211_PLINK_ESTAB;
+	changed |= mesh_plink_inc_estab_count(sdata);
+	changed |= mesh_set_ht_prot_mode(sdata);
+	changed |= mesh_set_short_slot_time(sdata);
+	mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
+	ieee80211_mps_sta_status_update(sta);
+	changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
+	return changed;
+}
+
+/**
+ * mesh_plink_fsm - step @sta MPM based on @event
+ *
+ * @sdata: interface
+ * @sta: mesh neighbor
+ * @event: peering event
+ *
+ * Return: changed MBSS flags
+ */
+static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
+			  struct sta_info *sta, enum plink_event event)
+{
+	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
+	enum ieee80211_self_protected_actioncode action = 0;
+	u32 changed = 0;
+	bool flush = false;
+
+	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
+		mplstates[sta->mesh->plink_state], mplevents[event]);
+
+	spin_lock_bh(&sta->mesh->plink_lock);
+	switch (sta->mesh->plink_state) {
+	case NL80211_PLINK_LISTEN:
+		switch (event) {
+		case CLS_ACPT:
+			mesh_plink_fsm_restart(sta);
+			break;
+		case OPN_ACPT:
+			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
+			sta->mesh->llid = mesh_get_new_llid(sdata);
+			mesh_plink_timer_set(sta,
+					     mshcfg->dot11MeshRetryTimeout);
+
+			/* set the non-peer mode to active during peering */
+			changed |= ieee80211_mps_local_status_update(sdata);
+			action = WLAN_SP_MESH_PEERING_OPEN;
+			break;
+		default:
+			break;
+		}
+		break;
+	case NL80211_PLINK_OPN_SNT:
+		switch (event) {
+		case OPN_RJCT:
+		case CNF_RJCT:
+		case CLS_ACPT:
+			mesh_plink_close(sdata, sta, event);
+			action = WLAN_SP_MESH_PEERING_CLOSE;
+			break;
+		case OPN_ACPT:
+			/* retry timer is left untouched */
+			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
+			action = WLAN_SP_MESH_PEERING_CONFIRM;
+			break;
+		case CNF_ACPT:
+			sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
+			mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
+			break;
+		default:
+			break;
+		}
+		break;
+	case NL80211_PLINK_OPN_RCVD:
+		switch (event) {
+		case OPN_RJCT:
+		case CNF_RJCT:
+		case CLS_ACPT:
+			mesh_plink_close(sdata, sta, event);
+			action = WLAN_SP_MESH_PEERING_CLOSE;
+			break;
+		case OPN_ACPT:
+			action = WLAN_SP_MESH_PEERING_CONFIRM;
+			break;
+		case CNF_ACPT:
+			changed |= mesh_plink_establish(sdata, sta);
+			break;
+		default:
+			break;
+		}
+		break;
+	case NL80211_PLINK_CNF_RCVD:
+		switch (event) {
+		case OPN_RJCT:
+		case CNF_RJCT:
+		case CLS_ACPT:
+			mesh_plink_close(sdata, sta, event);
+			action = WLAN_SP_MESH_PEERING_CLOSE;
+			break;
+		case OPN_ACPT:
+			changed |= mesh_plink_establish(sdata, sta);
+			action = WLAN_SP_MESH_PEERING_CONFIRM;
+			break;
+		default:
+			break;
+		}
+		break;
+	case NL80211_PLINK_ESTAB:
+		switch (event) {
+		case CLS_ACPT:
+			changed |= __mesh_plink_deactivate(sta);
+			changed |= mesh_set_ht_prot_mode(sdata);
+			changed |= mesh_set_short_slot_time(sdata);
+			mesh_plink_close(sdata, sta, event);
+			action = WLAN_SP_MESH_PEERING_CLOSE;
+			flush = true;
+			break;
+		case OPN_ACPT:
+			action = WLAN_SP_MESH_PEERING_CONFIRM;
+			break;
+		default:
+			break;
+		}
+		break;
+	case NL80211_PLINK_HOLDING:
+		switch (event) {
+		case CLS_ACPT:
+			del_timer(&sta->mesh->plink_timer);
+			mesh_plink_fsm_restart(sta);
+			break;
+		case OPN_ACPT:
+		case CNF_ACPT:
+		case OPN_RJCT:
+		case CNF_RJCT:
+			action = WLAN_SP_MESH_PEERING_CLOSE;
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		/* should not get here, PLINK_BLOCKED is dealt with at the
+		 * beginning of the function
+		 */
+		break;
+	}
+	spin_unlock_bh(&sta->mesh->plink_lock);
+	if (flush)
+		mesh_path_flush_by_nexthop(sta);
+	if (action) {
+		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
+				    sta->mesh->llid, sta->mesh->plid,
+				    sta->mesh->reason);
+
+		/* also send confirm in open case */
+		if (action == WLAN_SP_MESH_PEERING_OPEN) {
+			mesh_plink_frame_tx(sdata, sta,
+					    WLAN_SP_MESH_PEERING_CONFIRM,
+					    sta->sta.addr, sta->mesh->llid,
+					    sta->mesh->plid, 0);
+		}
+	}
+
+	return changed;
+}
+
+/*
+ * mesh_plink_get_event - get correct MPM event
+ *
+ * @sdata: interface
+ * @sta: peer, leave NULL if processing a frame from a new suitable peer
+ * @elems: peering management IEs
+ * @ftype: frame type
+ * @llid: peer's peer link ID
+ * @plid: peer's local link ID
+ *
+ * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
+ * an error.
+ */
+static enum plink_event
+mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
+		     struct sta_info *sta,
+		     struct ieee802_11_elems *elems,
+		     enum ieee80211_self_protected_actioncode ftype,
+		     u16 llid, u16 plid)
+{
+	enum plink_event event = PLINK_UNDEFINED;
+	u8 ie_len = elems->peering_len;
+	bool matches_local;
+
+	matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
+			 mesh_matches_local(sdata, elems));
+
+	/* deny open request from non-matching peer */
+	if (!matches_local && !sta) {
+		event = OPN_RJCT;
+		goto out;
+	}
+
+	if (!sta) {
+		if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
+			mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
+			goto out;
+		}
+		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
+		if (!mesh_plink_free_count(sdata)) {
+			mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
+			goto out;
+		}
+
+		/* new matching peer */
+		event = OPN_ACPT;
+		goto out;
+	} else {
+		if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
+			mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
+			goto out;
+		}
+		if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
+			goto out;
+	}
+
+	switch (ftype) {
+	case WLAN_SP_MESH_PEERING_OPEN:
+		if (!matches_local)
+			event = OPN_RJCT;
+		else if (!mesh_plink_free_count(sdata) ||
+			 (sta->mesh->plid && sta->mesh->plid != plid))
+			event = OPN_IGNR;
+		else
+			event = OPN_ACPT;
+		break;
+	case WLAN_SP_MESH_PEERING_CONFIRM:
+		if (!matches_local)
+			event = CNF_RJCT;
+		else if (!mesh_plink_free_count(sdata) ||
+			 sta->mesh->llid != llid ||
+			 (sta->mesh->plid && sta->mesh->plid != plid))
+			event = CNF_IGNR;
+		else
+			event = CNF_ACPT;
+		break;
+	case WLAN_SP_MESH_PEERING_CLOSE:
+		if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
+			/* Do not check for llid or plid. This does not
+			 * follow the standard but since multiple plinks
+			 * per sta are not supported, it is necessary in
+			 * order to avoid a livelock when MP A sees an
+			 * establish peer link to MP B but MP B does not
+			 * see it. This can be caused by a timeout in
+			 * B's peer link establishment or B beign
+			 * restarted.
+			 */
+			event = CLS_ACPT;
+		else if (sta->mesh->plid != plid)
+			event = CLS_IGNR;
+		else if (ie_len == 8 && sta->mesh->llid != llid)
+			event = CLS_IGNR;
+		else
+			event = CLS_ACPT;
+		break;
+	default:
+		mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
+		break;
+	}
+
+out:
+	return event;
+}
+
+static void
+mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
+			 struct ieee80211_mgmt *mgmt,
+			 struct ieee802_11_elems *elems,
+			 struct ieee80211_rx_status *rx_status)
+{
+
+	struct sta_info *sta;
+	enum plink_event event;
+	enum ieee80211_self_protected_actioncode ftype;
+	u32 changed = 0;
+	u8 ie_len = elems->peering_len;
+	u16 plid, llid = 0;
+
+	if (!elems->peering) {
+		mpl_dbg(sdata,
+			"Mesh plink: missing necessary peer link ie\n");
+		return;
+	}
+
+	if (elems->rsn_len &&
+	    sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
+		mpl_dbg(sdata,
+			"Mesh plink: can't establish link with secure peer\n");
+		return;
+	}
+
+	ftype = mgmt->u.action.u.self_prot.action_code;
+	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
+	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
+	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
+							&& ie_len != 8)) {
+		mpl_dbg(sdata,
+			"Mesh plink: incorrect plink ie length %d %d\n",
+			ftype, ie_len);
+		return;
+	}
+
+	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
+	    (!elems->mesh_id || !elems->mesh_config)) {
+		mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
+		return;
+	}
+	/* Note the lines below are correct, the llid in the frame is the plid
+	 * from the point of view of this host.
+	 */
+	plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
+	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
+	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
+		llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
+
+	/* WARNING: Only for sta pointer, is dropped & re-acquired */
+	rcu_read_lock();
+
+	sta = sta_info_get(sdata, mgmt->sa);
+
+	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
+	    !rssi_threshold_check(sdata, sta)) {
+		mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
+			mgmt->sa);
+		goto unlock_rcu;
+	}
+
+	/* Now we will figure out the appropriate event... */
+	event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
+
+	if (event == OPN_ACPT) {
+		rcu_read_unlock();
+		/* allocate sta entry if necessary and update info */
+		sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
+		if (!sta) {
+			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
+			goto unlock_rcu;
+		}
+		sta->mesh->plid = plid;
+	} else if (!sta && event == OPN_RJCT) {
+		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
+				    mgmt->sa, 0, plid,
+				    WLAN_REASON_MESH_CONFIG);
+		goto unlock_rcu;
+	} else if (!sta || event == PLINK_UNDEFINED) {
+		/* something went wrong */
+		goto unlock_rcu;
+	}
+
+	if (event == CNF_ACPT) {
+		/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
+		if (!sta->mesh->plid)
+			sta->mesh->plid = plid;
+
+		sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
+	}
+
+	changed |= mesh_plink_fsm(sdata, sta, event);
+
+unlock_rcu:
+	rcu_read_unlock();
+
+	if (changed)
+		ieee80211_mbss_info_change_notify(sdata, changed);
+}
+
+void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
+			 struct ieee80211_mgmt *mgmt, size_t len,
+			 struct ieee80211_rx_status *rx_status)
+{
+	struct ieee802_11_elems *elems;
+	size_t baselen;
+	u8 *baseaddr;
+
+	/* need action_code, aux */
+	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
+		return;
+
+	if (sdata->u.mesh.user_mpm)
+		/* userspace must register for these */
+		return;
+
+	if (is_multicast_ether_addr(mgmt->da)) {
+		mpl_dbg(sdata,
+			"Mesh plink: ignore frame from multicast address\n");
+		return;
+	}
+
+	baseaddr = mgmt->u.action.u.self_prot.variable;
+	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
+	if (mgmt->u.action.u.self_prot.action_code ==
+						WLAN_SP_MESH_PEERING_CONFIRM) {
+		baseaddr += 4;
+		baselen += 4;
+
+		if (baselen > len)
+			return;
+	}
+	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true, NULL);
+	if (elems) {
+		mesh_process_plink_frame(sdata, mgmt, elems, rx_status);
+		kfree(elems);
+	}
+}