forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
213 lines
6.4 KiB
213 lines
6.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* Copyright 2011-2012, Pavel Zubarev <[email protected]> |
|
* Copyright 2011-2012, Marco Porsch <[email protected]> |
|
* Copyright 2011-2012, cozybit Inc. |
|
* Copyright (C) 2021 Intel Corporation |
|
*/ |
|
|
|
#include "ieee80211_i.h" |
|
#include "mesh.h" |
|
#include "driver-ops.h" |
|
|
|
/* This is not in the standard. It represents a tolerable tsf drift below |
|
* which we do no TSF adjustment. |
|
*/ |
|
#define TOFFSET_MINIMUM_ADJUSTMENT 10 |
|
|
|
/* This is not in the standard. It is a margin added to the |
|
* Toffset setpoint to mitigate TSF overcorrection |
|
* introduced by TSF adjustment latency. |
|
*/ |
|
#define TOFFSET_SET_MARGIN 20 |
|
|
|
/* This is not in the standard. It represents the maximum Toffset jump above |
|
* which we'll invalidate the Toffset setpoint and choose a new setpoint. This |
|
* could be, for instance, in case a neighbor is restarted and its TSF counter |
|
* reset. |
|
*/ |
|
#define TOFFSET_MAXIMUM_ADJUSTMENT 800 /* 0.8 ms */ |
|
|
|
struct sync_method { |
|
u8 method; |
|
struct ieee80211_mesh_sync_ops ops; |
|
}; |
|
|
|
/** |
|
* mesh_peer_tbtt_adjusting - check if an mp is currently adjusting its TBTT |
|
* |
|
* @cfg: mesh config element from the mesh peer (or %NULL) |
|
*/ |
|
static bool mesh_peer_tbtt_adjusting(const struct ieee80211_meshconf_ie *cfg) |
|
{ |
|
return cfg && |
|
(cfg->meshconf_cap & IEEE80211_MESHCONF_CAPAB_TBTT_ADJUSTING); |
|
} |
|
|
|
void mesh_sync_adjust_tsf(struct ieee80211_sub_if_data *sdata) |
|
{ |
|
struct ieee80211_local *local = sdata->local; |
|
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; |
|
/* sdata->vif.bss_conf.beacon_int in 1024us units, 0.04% */ |
|
u64 beacon_int_fraction = sdata->vif.bss_conf.beacon_int * 1024 / 2500; |
|
u64 tsf; |
|
u64 tsfdelta; |
|
|
|
spin_lock_bh(&ifmsh->sync_offset_lock); |
|
if (ifmsh->sync_offset_clockdrift_max < beacon_int_fraction) { |
|
msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting\n", |
|
(long long) ifmsh->sync_offset_clockdrift_max); |
|
tsfdelta = -ifmsh->sync_offset_clockdrift_max; |
|
ifmsh->sync_offset_clockdrift_max = 0; |
|
} else { |
|
msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting by %llu\n", |
|
(long long) ifmsh->sync_offset_clockdrift_max, |
|
(unsigned long long) beacon_int_fraction); |
|
tsfdelta = -beacon_int_fraction; |
|
ifmsh->sync_offset_clockdrift_max -= beacon_int_fraction; |
|
} |
|
spin_unlock_bh(&ifmsh->sync_offset_lock); |
|
|
|
if (local->ops->offset_tsf) { |
|
drv_offset_tsf(local, sdata, tsfdelta); |
|
} else { |
|
tsf = drv_get_tsf(local, sdata); |
|
if (tsf != -1ULL) |
|
drv_set_tsf(local, sdata, tsf + tsfdelta); |
|
} |
|
} |
|
|
|
static void |
|
mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata, u16 stype, |
|
struct ieee80211_mgmt *mgmt, unsigned int len, |
|
const struct ieee80211_meshconf_ie *mesh_cfg, |
|
struct ieee80211_rx_status *rx_status) |
|
{ |
|
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; |
|
struct ieee80211_local *local = sdata->local; |
|
struct sta_info *sta; |
|
u64 t_t, t_r; |
|
|
|
WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET); |
|
|
|
/* standard mentions only beacons */ |
|
if (stype != IEEE80211_STYPE_BEACON) |
|
return; |
|
|
|
/* |
|
* Get time when timestamp field was received. If we don't |
|
* have rx timestamps, then use current tsf as an approximation. |
|
* drv_get_tsf() must be called before entering the rcu-read |
|
* section. |
|
*/ |
|
if (ieee80211_have_rx_timestamp(rx_status)) |
|
t_r = ieee80211_calculate_rx_timestamp(local, rx_status, |
|
len + FCS_LEN, 24); |
|
else |
|
t_r = drv_get_tsf(local, sdata); |
|
|
|
rcu_read_lock(); |
|
sta = sta_info_get(sdata, mgmt->sa); |
|
if (!sta) |
|
goto no_sync; |
|
|
|
/* check offset sync conditions (13.13.2.2.1) |
|
* |
|
* TODO also sync to |
|
* dot11MeshNbrOffsetMaxNeighbor non-peer non-MBSS neighbors |
|
*/ |
|
|
|
if (mesh_peer_tbtt_adjusting(mesh_cfg)) { |
|
msync_dbg(sdata, "STA %pM : is adjusting TBTT\n", |
|
sta->sta.addr); |
|
goto no_sync; |
|
} |
|
|
|
/* Timing offset calculation (see 13.13.2.2.2) */ |
|
t_t = le64_to_cpu(mgmt->u.beacon.timestamp); |
|
sta->mesh->t_offset = t_t - t_r; |
|
|
|
if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) { |
|
s64 t_clockdrift = sta->mesh->t_offset_setpoint - sta->mesh->t_offset; |
|
msync_dbg(sdata, |
|
"STA %pM : t_offset=%lld, t_offset_setpoint=%lld, t_clockdrift=%lld\n", |
|
sta->sta.addr, (long long) sta->mesh->t_offset, |
|
(long long) sta->mesh->t_offset_setpoint, |
|
(long long) t_clockdrift); |
|
|
|
if (t_clockdrift > TOFFSET_MAXIMUM_ADJUSTMENT || |
|
t_clockdrift < -TOFFSET_MAXIMUM_ADJUSTMENT) { |
|
msync_dbg(sdata, |
|
"STA %pM : t_clockdrift=%lld too large, setpoint reset\n", |
|
sta->sta.addr, |
|
(long long) t_clockdrift); |
|
clear_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN); |
|
goto no_sync; |
|
} |
|
|
|
spin_lock_bh(&ifmsh->sync_offset_lock); |
|
if (t_clockdrift > ifmsh->sync_offset_clockdrift_max) |
|
ifmsh->sync_offset_clockdrift_max = t_clockdrift; |
|
spin_unlock_bh(&ifmsh->sync_offset_lock); |
|
} else { |
|
sta->mesh->t_offset_setpoint = sta->mesh->t_offset - TOFFSET_SET_MARGIN; |
|
set_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN); |
|
msync_dbg(sdata, |
|
"STA %pM : offset was invalid, t_offset=%lld\n", |
|
sta->sta.addr, |
|
(long long) sta->mesh->t_offset); |
|
} |
|
|
|
no_sync: |
|
rcu_read_unlock(); |
|
} |
|
|
|
static void mesh_sync_offset_adjust_tsf(struct ieee80211_sub_if_data *sdata, |
|
struct beacon_data *beacon) |
|
{ |
|
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; |
|
|
|
WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET); |
|
WARN_ON(!rcu_read_lock_held()); |
|
|
|
spin_lock_bh(&ifmsh->sync_offset_lock); |
|
|
|
if (ifmsh->sync_offset_clockdrift_max > TOFFSET_MINIMUM_ADJUSTMENT) { |
|
/* Since ajusting the tsf here would |
|
* require a possibly blocking call |
|
* to the driver tsf setter, we punt |
|
* the tsf adjustment to the mesh tasklet |
|
*/ |
|
msync_dbg(sdata, |
|
"TSF : kicking off TSF adjustment with clockdrift_max=%lld\n", |
|
ifmsh->sync_offset_clockdrift_max); |
|
set_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags); |
|
} else { |
|
msync_dbg(sdata, |
|
"TSF : max clockdrift=%lld; too small to adjust\n", |
|
(long long)ifmsh->sync_offset_clockdrift_max); |
|
ifmsh->sync_offset_clockdrift_max = 0; |
|
} |
|
spin_unlock_bh(&ifmsh->sync_offset_lock); |
|
} |
|
|
|
static const struct sync_method sync_methods[] = { |
|
{ |
|
.method = IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET, |
|
.ops = { |
|
.rx_bcn_presp = &mesh_sync_offset_rx_bcn_presp, |
|
.adjust_tsf = &mesh_sync_offset_adjust_tsf, |
|
} |
|
}, |
|
}; |
|
|
|
const struct ieee80211_mesh_sync_ops *ieee80211_mesh_sync_ops_get(u8 method) |
|
{ |
|
int i; |
|
|
|
for (i = 0 ; i < ARRAY_SIZE(sync_methods); ++i) { |
|
if (sync_methods[i].method == method) |
|
return &sync_methods[i].ops; |
|
} |
|
return NULL; |
|
}
|
|
|