forked from mirrors/linux
4b482281ee
Correct spelling here and there as suggested by codespell. Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Link: https://patch.msgid.link/20240913084919.118862-1-dmantipov@yandex.ru Signed-off-by: Johannes Berg <johannes.berg@intel.com>
215 lines
6.4 KiB
C
215 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2011-2012, Pavel Zubarev <pavel.zubarev@gmail.com>
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* Copyright 2011-2012, Marco Porsch <marco.porsch@s2005.tu-chemnitz.de>
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* Copyright 2011-2012, cozybit Inc.
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* Copyright (C) 2021,2023 Intel Corporation
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*/
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#include "ieee80211_i.h"
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#include "mesh.h"
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#include "driver-ops.h"
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/* This is not in the standard. It represents a tolerable tsf drift below
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* which we do no TSF adjustment.
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*/
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#define TOFFSET_MINIMUM_ADJUSTMENT 10
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/* This is not in the standard. It is a margin added to the
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* Toffset setpoint to mitigate TSF overcorrection
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* introduced by TSF adjustment latency.
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*/
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#define TOFFSET_SET_MARGIN 20
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/* This is not in the standard. It represents the maximum Toffset jump above
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* which we'll invalidate the Toffset setpoint and choose a new setpoint. This
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* could be, for instance, in case a neighbor is restarted and its TSF counter
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* reset.
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*/
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#define TOFFSET_MAXIMUM_ADJUSTMENT 800 /* 0.8 ms */
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struct sync_method {
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u8 method;
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struct ieee80211_mesh_sync_ops ops;
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};
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/**
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* mesh_peer_tbtt_adjusting - check if an mp is currently adjusting its TBTT
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*
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* @cfg: mesh config element from the mesh peer (or %NULL)
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*
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* Returns: If the mesh peer is currently adjusting its TBTT
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*/
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static bool mesh_peer_tbtt_adjusting(const struct ieee80211_meshconf_ie *cfg)
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{
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return cfg &&
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(cfg->meshconf_cap & IEEE80211_MESHCONF_CAPAB_TBTT_ADJUSTING);
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}
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void mesh_sync_adjust_tsf(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_local *local = sdata->local;
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struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
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/* sdata->vif.bss_conf.beacon_int in 1024us units, 0.04% */
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u64 beacon_int_fraction = sdata->vif.bss_conf.beacon_int * 1024 / 2500;
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u64 tsf;
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u64 tsfdelta;
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spin_lock_bh(&ifmsh->sync_offset_lock);
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if (ifmsh->sync_offset_clockdrift_max < beacon_int_fraction) {
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msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting\n",
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(long long) ifmsh->sync_offset_clockdrift_max);
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tsfdelta = -ifmsh->sync_offset_clockdrift_max;
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ifmsh->sync_offset_clockdrift_max = 0;
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} else {
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msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting by %llu\n",
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(long long) ifmsh->sync_offset_clockdrift_max,
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(unsigned long long) beacon_int_fraction);
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tsfdelta = -beacon_int_fraction;
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ifmsh->sync_offset_clockdrift_max -= beacon_int_fraction;
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}
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spin_unlock_bh(&ifmsh->sync_offset_lock);
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if (local->ops->offset_tsf) {
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drv_offset_tsf(local, sdata, tsfdelta);
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} else {
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tsf = drv_get_tsf(local, sdata);
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if (tsf != -1ULL)
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drv_set_tsf(local, sdata, tsf + tsfdelta);
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}
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}
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static void
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mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata, u16 stype,
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struct ieee80211_mgmt *mgmt, unsigned int len,
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const struct ieee80211_meshconf_ie *mesh_cfg,
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struct ieee80211_rx_status *rx_status)
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{
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struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
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struct ieee80211_local *local = sdata->local;
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struct sta_info *sta;
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u64 t_t, t_r;
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WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET);
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/* standard mentions only beacons */
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if (stype != IEEE80211_STYPE_BEACON)
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return;
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/*
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* Get time when timestamp field was received. If we don't
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* have rx timestamps, then use current tsf as an approximation.
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* drv_get_tsf() must be called before entering the rcu-read
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* section.
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*/
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if (ieee80211_have_rx_timestamp(rx_status))
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t_r = ieee80211_calculate_rx_timestamp(local, rx_status,
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len + FCS_LEN, 24);
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else
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t_r = drv_get_tsf(local, sdata);
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rcu_read_lock();
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sta = sta_info_get(sdata, mgmt->sa);
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if (!sta)
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goto no_sync;
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/* check offset sync conditions (13.13.2.2.1)
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*
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* TODO also sync to
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* dot11MeshNbrOffsetMaxNeighbor non-peer non-MBSS neighbors
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*/
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if (mesh_peer_tbtt_adjusting(mesh_cfg)) {
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msync_dbg(sdata, "STA %pM : is adjusting TBTT\n",
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sta->sta.addr);
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goto no_sync;
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}
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/* Timing offset calculation (see 13.13.2.2.2) */
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t_t = le64_to_cpu(mgmt->u.beacon.timestamp);
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sta->mesh->t_offset = t_t - t_r;
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if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) {
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s64 t_clockdrift = sta->mesh->t_offset_setpoint - sta->mesh->t_offset;
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msync_dbg(sdata,
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"STA %pM : t_offset=%lld, t_offset_setpoint=%lld, t_clockdrift=%lld\n",
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sta->sta.addr, (long long) sta->mesh->t_offset,
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(long long) sta->mesh->t_offset_setpoint,
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(long long) t_clockdrift);
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if (t_clockdrift > TOFFSET_MAXIMUM_ADJUSTMENT ||
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t_clockdrift < -TOFFSET_MAXIMUM_ADJUSTMENT) {
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msync_dbg(sdata,
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"STA %pM : t_clockdrift=%lld too large, setpoint reset\n",
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sta->sta.addr,
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(long long) t_clockdrift);
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clear_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN);
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goto no_sync;
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}
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spin_lock_bh(&ifmsh->sync_offset_lock);
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if (t_clockdrift > ifmsh->sync_offset_clockdrift_max)
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ifmsh->sync_offset_clockdrift_max = t_clockdrift;
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spin_unlock_bh(&ifmsh->sync_offset_lock);
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} else {
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sta->mesh->t_offset_setpoint = sta->mesh->t_offset - TOFFSET_SET_MARGIN;
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set_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN);
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msync_dbg(sdata,
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"STA %pM : offset was invalid, t_offset=%lld\n",
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sta->sta.addr,
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(long long) sta->mesh->t_offset);
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}
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no_sync:
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rcu_read_unlock();
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}
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static void mesh_sync_offset_adjust_tsf(struct ieee80211_sub_if_data *sdata,
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struct beacon_data *beacon)
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{
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struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
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WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET);
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WARN_ON(!rcu_read_lock_held());
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spin_lock_bh(&ifmsh->sync_offset_lock);
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if (ifmsh->sync_offset_clockdrift_max > TOFFSET_MINIMUM_ADJUSTMENT) {
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/* Since adjusting the tsf here would
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* require a possibly blocking call
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* to the driver tsf setter, we punt
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* the tsf adjustment to the mesh tasklet
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*/
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msync_dbg(sdata,
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"TSF : kicking off TSF adjustment with clockdrift_max=%lld\n",
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ifmsh->sync_offset_clockdrift_max);
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set_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags);
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} else {
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msync_dbg(sdata,
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"TSF : max clockdrift=%lld; too small to adjust\n",
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(long long)ifmsh->sync_offset_clockdrift_max);
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ifmsh->sync_offset_clockdrift_max = 0;
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}
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spin_unlock_bh(&ifmsh->sync_offset_lock);
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}
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static const struct sync_method sync_methods[] = {
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{
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.method = IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET,
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.ops = {
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.rx_bcn_presp = &mesh_sync_offset_rx_bcn_presp,
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.adjust_tsf = &mesh_sync_offset_adjust_tsf,
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}
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},
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};
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const struct ieee80211_mesh_sync_ops *ieee80211_mesh_sync_ops_get(u8 method)
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{
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int i;
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for (i = 0 ; i < ARRAY_SIZE(sync_methods); ++i) {
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if (sync_methods[i].method == method)
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return &sync_methods[i].ops;
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}
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return NULL;
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}
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