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ubuntu-linux-kernel/net/mac80211/mesh_plink.c

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/*
* 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 <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->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.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
*
* 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;
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.bandwidth > IEEE80211_STA_RX_BW_20)
continue;
if (!sta->sta.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;
int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
int err = -ENOMEM;
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) +
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))
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, bool insert)
{
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.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->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.supp_rates[sband->band] != rates)
changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
sta->sta.supp_rates[sband->band] = rates;
if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
elems->ht_cap_elem, sta))
changed |= IEEE80211_RC_BW_CHANGED;
ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
elems->vht_cap_elem, sta);
if (bw != sta->sta.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.bandwidth != IEEE80211_STA_RX_BW_20)
changed |= IEEE80211_RC_BW_CHANGED;
sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
}
if (insert)
rate_control_rate_init(sta);
else
rate_control_rate_update(local, sband, sta, 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 = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
sizeof(*aid_map), 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);
kfree(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 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))
cfg80211_notify_new_peer_candidate(sdata->dev, addr,
elems->ie_start,
elems->total_len,
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.
*
* 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) __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, false);
} else {
rcu_read_unlock();
/* can't run atomic */
sta = mesh_sta_info_alloc(sdata, addr, elems);
if (!sta) {
rcu_read_lock();
return NULL;
}
mesh_sta_info_init(sdata, sta, elems, true);
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
*
* Initiates peering if appropriate.
*/
void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
u8 *hw_addr,
struct ieee802_11_elems *elems)
{
struct sta_info *sta;
u32 changed = 0;
sta = mesh_sta_info_get(sdata, hw_addr, elems);
if (!sta)
goto out;
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;
/* fall through on else */
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;
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;
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 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);
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;
}
ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
mesh_process_plink_frame(sdata, mgmt, &elems);
}
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