// SPDX-License-Identifier: GPL-2.0-only/* * Copyright 2011-2012, Pavel Zubarev <pavel.zubarev@gmail.com> * Copyright 2011-2012, Marco Porsch <marco.porsch@s2005.tu-chemnitz.de> * Copyright 2011-2012, cozybit Inc. * Copyright (C) 2021,2023 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) * * Returns: If the mesh peer is currently adjusting its TBTT */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 voidmesh_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->hw, 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 adjusting 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;}