path: root/net/mac80211/mesh_plink.c

/*
 * Copyright (c) 2008, 2009 open80211s Ltd.
 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/random.h>
#include "ieee80211_i.h"
#include "rate.h"
#include "mesh.h"

#define PLINK_GET_LLID(p) (p + 2)
#define PLINK_GET_PLID(p) (p + 4)

#define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
				jiffies + HZ * t / 1000))

/* We only need a valid sta if user configured a minimum rssi_threshold. */
#define rssi_threshold_check(sta, sdata) \
		(sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
		(sta && (s8) -ewma_read(&sta->avg_signal) > \
		sdata->u.mesh.mshcfg.rssi_threshold))

enum plink_event {
	PLINK_UNDEFINED,
	OPN_ACPT,
	OPN_RJCT,
	OPN_IGNR,
	CNF_ACPT,
	CNF_RJCT,
	CNF_IGNR,
	CLS_ACPT,
	CLS_IGNR
};

static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
		enum ieee80211_self_protected_actioncode action,
		u8 *da, __le16 llid, __le16 plid, __le16 reason);

/**
 * 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->lock
 */
static inline void mesh_plink_fsm_restart(struct sta_info *sta)
{
	sta->plink_state = NL80211_PLINK_LISTEN;
	sta->llid = sta->plid = sta->reason = 0;
	sta->plink_retries = 0;
}

/**
 * mesh_set_ht_prot_mode - set correct HT protection mode
 *
 * 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 atleast 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;
	u32 changed = 0;
	u16 ht_opmode;
	bool non_ht_sta = false, ht20_sta = false;

	if (sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT)
		return 0;

	rcu_read_lock();
	list_for_each_entry_rcu(sta, &local->sta_list, list) {
		if (sdata != sta->sdata ||
		    sta->plink_state != NL80211_PLINK_ESTAB)
			continue;

		switch (sta->ch_width) {
		case NL80211_CHAN_WIDTH_20_NOHT:
			mpl_dbg(sdata,
				"mesh_plink %pM: nonHT sta (%pM) is present\n",
				sdata->vif.addr, sta->sta.addr);
			non_ht_sta = true;
			goto out;
		case NL80211_CHAN_WIDTH_20:
			mpl_dbg(sdata,
				"mesh_plink %pM: HT20 sta (%pM) is present\n",
				sdata->vif.addr, sta->sta.addr);
			ht20_sta = true;
		default:
			break;
		}
	}
out:
	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) {
		sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
		sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
		changed = BSS_CHANGED_HT;
		mpl_dbg(sdata,
			"mesh_plink %pM: protection mode changed to %d\n",
			sdata->vif.addr, ht_opmode);
	}

	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
 * Returns beacon changed flag if the beacon content changed.
 *
 * Locking: the caller must hold sta->lock
 */
static u32 __mesh_plink_deactivate(struct sta_info *sta)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	u32 changed = 0;

	if (sta->plink_state == NL80211_PLINK_ESTAB)
		changed = mesh_plink_dec_estab_count(sdata);
	sta->plink_state = NL80211_PLINK_BLOCKED;
	mesh_path_flush_by_nexthop(sta);

	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
 */
void mesh_plink_deactivate(struct sta_info *sta)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	u32 changed;

	spin_lock_bh(&sta->lock);
	changed = __mesh_plink_deactivate(sta);
	sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
	mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
			    sta->sta.addr, sta->llid, sta->plid,
			    sta->reason);
	spin_unlock_bh(&sta->lock);

	ieee80211_bss_info_change_notify(sdata, changed);
}

static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
		enum ieee80211_self_protected_actioncode action,
		u8 *da, __le16 llid, __le16 plid, __le16 reason)