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Javier Cardonadbf498f2012-03-31 11:31:32 -07001/*
2 * Copyright 2011-2012, Pavel Zubarev <pavel.zubarev@gmail.com>
3 * Copyright 2011-2012, Marco Porsch <marco.porsch@s2005.tu-chemnitz.de>
4 * Copyright 2011-2012, cozybit Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include "ieee80211_i.h"
12#include "mesh.h"
13#include "driver-ops.h"
14
Masashi Honma445cd452016-12-08 10:15:51 +090015/* This is not in the standard. It represents a tolerable tsf drift below
Javier Cardonadbf498f2012-03-31 11:31:32 -070016 * which we do no TSF adjustment.
17 */
Javier Cardonaa802a6e2012-04-12 14:32:22 -070018#define TOFFSET_MINIMUM_ADJUSTMENT 10
19
Javier Cardonaec14bcd2012-04-12 14:32:23 -070020/* This is not in the standard. It is a margin added to the
21 * Toffset setpoint to mitigate TSF overcorrection
22 * introduced by TSF adjustment latency.
23 */
24#define TOFFSET_SET_MARGIN 20
25
Javier Cardonaa802a6e2012-04-12 14:32:22 -070026/* This is not in the standard. It represents the maximum Toffset jump above
27 * which we'll invalidate the Toffset setpoint and choose a new setpoint. This
28 * could be, for instance, in case a neighbor is restarted and its TSF counter
29 * reset.
Javier Cardonaec14bcd2012-04-12 14:32:23 -070030 */
Pedersen, Thomas3a537312016-09-28 16:56:31 -070031#define TOFFSET_MAXIMUM_ADJUSTMENT 800 /* 0.8 ms */
Javier Cardonadbf498f2012-03-31 11:31:32 -070032
33struct sync_method {
34 u8 method;
35 struct ieee80211_mesh_sync_ops ops;
36};
37
38/**
39 * mesh_peer_tbtt_adjusting - check if an mp is currently adjusting its TBTT
40 *
41 * @ie: information elements of a management frame from the mesh peer
42 */
43static bool mesh_peer_tbtt_adjusting(struct ieee802_11_elems *ie)
44{
45 return (ie->mesh_config->meshconf_cap &
Johannes Bergbf7cd942013-02-15 14:40:31 +010046 IEEE80211_MESHCONF_CAPAB_TBTT_ADJUSTING) != 0;
Javier Cardonadbf498f2012-03-31 11:31:32 -070047}
48
Masashi Honma445cd452016-12-08 10:15:51 +090049void mesh_sync_adjust_tsf(struct ieee80211_sub_if_data *sdata)
Javier Cardonadbf498f2012-03-31 11:31:32 -070050{
51 struct ieee80211_local *local = sdata->local;
52 struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
53 /* sdata->vif.bss_conf.beacon_int in 1024us units, 0.04% */
54 u64 beacon_int_fraction = sdata->vif.bss_conf.beacon_int * 1024 / 2500;
55 u64 tsf;
56 u64 tsfdelta;
57
58 spin_lock_bh(&ifmsh->sync_offset_lock);
Javier Cardonadbf498f2012-03-31 11:31:32 -070059 if (ifmsh->sync_offset_clockdrift_max < beacon_int_fraction) {
Masashi Honma445cd452016-12-08 10:15:51 +090060 msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting\n",
Johannes Bergbdcbd8e2012-06-22 11:29:50 +020061 (long long) ifmsh->sync_offset_clockdrift_max);
Javier Cardonadbf498f2012-03-31 11:31:32 -070062 tsfdelta = -ifmsh->sync_offset_clockdrift_max;
63 ifmsh->sync_offset_clockdrift_max = 0;
64 } else {
Masashi Honma445cd452016-12-08 10:15:51 +090065 msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting by %llu\n",
Johannes Bergbdcbd8e2012-06-22 11:29:50 +020066 (long long) ifmsh->sync_offset_clockdrift_max,
67 (unsigned long long) beacon_int_fraction);
Javier Cardonadbf498f2012-03-31 11:31:32 -070068 tsfdelta = -beacon_int_fraction;
69 ifmsh->sync_offset_clockdrift_max -= beacon_int_fraction;
70 }
Thomas Pedersen55fabef2012-10-05 17:57:39 -070071 spin_unlock_bh(&ifmsh->sync_offset_lock);
Javier Cardonadbf498f2012-03-31 11:31:32 -070072
Pedersen, Thomas354d3812016-09-28 16:56:28 -070073 if (local->ops->offset_tsf) {
74 drv_offset_tsf(local, sdata, tsfdelta);
75 } else {
76 tsf = drv_get_tsf(local, sdata);
77 if (tsf != -1ULL)
78 drv_set_tsf(local, sdata, tsf + tsfdelta);
79 }
Javier Cardonadbf498f2012-03-31 11:31:32 -070080}
81
82static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
83 u16 stype,
84 struct ieee80211_mgmt *mgmt,
85 struct ieee802_11_elems *elems,
86 struct ieee80211_rx_status *rx_status)
87{
88 struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
89 struct ieee80211_local *local = sdata->local;
90 struct sta_info *sta;
91 u64 t_t, t_r;
92
93 WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET);
94
95 /* standard mentions only beacons */
96 if (stype != IEEE80211_STYPE_BEACON)
97 return;
98
Bob Copelandce953202013-11-18 17:25:28 -050099 /*
100 * Get time when timestamp field was received. If we don't
101 * have rx timestamps, then use current tsf as an approximation.
102 * drv_get_tsf() must be called before entering the rcu-read
103 * section.
104 */
105 if (ieee80211_have_rx_timestamp(rx_status))
106 t_r = ieee80211_calculate_rx_timestamp(local, rx_status,
107 24 + 12 +
108 elems->total_len +
109 FCS_LEN,
110 24);
111 else
112 t_r = drv_get_tsf(local, sdata);
Javier Cardonadbf498f2012-03-31 11:31:32 -0700113
114 rcu_read_lock();
115 sta = sta_info_get(sdata, mgmt->sa);
116 if (!sta)
117 goto no_sync;
118
119 /* check offset sync conditions (13.13.2.2.1)
120 *
121 * TODO also sync to
122 * dot11MeshNbrOffsetMaxNeighbor non-peer non-MBSS neighbors
123 */
124
125 if (elems->mesh_config && mesh_peer_tbtt_adjusting(elems)) {
Johannes Bergbf7cd942013-02-15 14:40:31 +0100126 msync_dbg(sdata, "STA %pM : is adjusting TBTT\n",
127 sta->sta.addr);
Javier Cardonadbf498f2012-03-31 11:31:32 -0700128 goto no_sync;
129 }
130
Javier Cardonadbf498f2012-03-31 11:31:32 -0700131 /* Timing offset calculation (see 13.13.2.2.2) */
132 t_t = le64_to_cpu(mgmt->u.beacon.timestamp);
Johannes Berg433f5bc2015-06-17 10:31:00 +0200133 sta->mesh->t_offset = t_t - t_r;
Javier Cardonadbf498f2012-03-31 11:31:32 -0700134
135 if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) {
Johannes Berg433f5bc2015-06-17 10:31:00 +0200136 s64 t_clockdrift = sta->mesh->t_offset_setpoint - sta->mesh->t_offset;
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200137 msync_dbg(sdata,
Johannes Berg433f5bc2015-06-17 10:31:00 +0200138 "STA %pM : t_offset=%lld, t_offset_setpoint=%lld, t_clockdrift=%lld\n",
139 sta->sta.addr, (long long) sta->mesh->t_offset,
140 (long long) sta->mesh->t_offset_setpoint,
Javier Cardonadbf498f2012-03-31 11:31:32 -0700141 (long long) t_clockdrift);
Javier Cardonaa802a6e2012-04-12 14:32:22 -0700142
143 if (t_clockdrift > TOFFSET_MAXIMUM_ADJUSTMENT ||
Johannes Bergbf7cd942013-02-15 14:40:31 +0100144 t_clockdrift < -TOFFSET_MAXIMUM_ADJUSTMENT) {
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200145 msync_dbg(sdata,
146 "STA %pM : t_clockdrift=%lld too large, setpoint reset\n",
Javier Cardonaa802a6e2012-04-12 14:32:22 -0700147 sta->sta.addr,
148 (long long) t_clockdrift);
149 clear_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN);
150 goto no_sync;
151 }
152
Javier Cardonadbf498f2012-03-31 11:31:32 -0700153 spin_lock_bh(&ifmsh->sync_offset_lock);
Johannes Bergbf7cd942013-02-15 14:40:31 +0100154 if (t_clockdrift > ifmsh->sync_offset_clockdrift_max)
155 ifmsh->sync_offset_clockdrift_max = t_clockdrift;
Javier Cardonadbf498f2012-03-31 11:31:32 -0700156 spin_unlock_bh(&ifmsh->sync_offset_lock);
Javier Cardonadbf498f2012-03-31 11:31:32 -0700157 } else {
Johannes Berg433f5bc2015-06-17 10:31:00 +0200158 sta->mesh->t_offset_setpoint = sta->mesh->t_offset - TOFFSET_SET_MARGIN;
Javier Cardonadbf498f2012-03-31 11:31:32 -0700159 set_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN);
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200160 msync_dbg(sdata,
Johannes Berg433f5bc2015-06-17 10:31:00 +0200161 "STA %pM : offset was invalid, t_offset=%lld\n",
Javier Cardonadbf498f2012-03-31 11:31:32 -0700162 sta->sta.addr,
Johannes Berg433f5bc2015-06-17 10:31:00 +0200163 (long long) sta->mesh->t_offset);
Javier Cardonadbf498f2012-03-31 11:31:32 -0700164 }
Javier Cardonadbf498f2012-03-31 11:31:32 -0700165
166no_sync:
167 rcu_read_unlock();
168}
169
Masashi Honma445cd452016-12-08 10:15:51 +0900170static void mesh_sync_offset_adjust_tsf(struct ieee80211_sub_if_data *sdata,
Thomas Pedersen43552be2013-12-15 13:14:16 -0800171 struct beacon_data *beacon)
Javier Cardonadbf498f2012-03-31 11:31:32 -0700172{
173 struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
174
Johannes Bergbf7cd942013-02-15 14:40:31 +0100175 WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET);
Johannes Berg8c5bb1f2014-04-29 17:55:26 +0200176 WARN_ON(!rcu_read_lock_held());
Javier Cardonadbf498f2012-03-31 11:31:32 -0700177
178 spin_lock_bh(&ifmsh->sync_offset_lock);
179
Johannes Bergbf7cd942013-02-15 14:40:31 +0100180 if (ifmsh->sync_offset_clockdrift_max > TOFFSET_MINIMUM_ADJUSTMENT) {
Javier Cardonadbf498f2012-03-31 11:31:32 -0700181 /* Since ajusting the tsf here would
182 * require a possibly blocking call
183 * to the driver tsf setter, we punt
184 * the tsf adjustment to the mesh tasklet
185 */
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200186 msync_dbg(sdata,
Masashi Honma445cd452016-12-08 10:15:51 +0900187 "TSF : kicking off TSF adjustment with clockdrift_max=%lld\n",
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200188 ifmsh->sync_offset_clockdrift_max);
Johannes Bergbf7cd942013-02-15 14:40:31 +0100189 set_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags);
Javier Cardonadbf498f2012-03-31 11:31:32 -0700190 } else {
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200191 msync_dbg(sdata,
Masashi Honma445cd452016-12-08 10:15:51 +0900192 "TSF : max clockdrift=%lld; too small to adjust\n",
Johannes Bergbdcbd8e2012-06-22 11:29:50 +0200193 (long long)ifmsh->sync_offset_clockdrift_max);
Javier Cardonadbf498f2012-03-31 11:31:32 -0700194 ifmsh->sync_offset_clockdrift_max = 0;
195 }
196 spin_unlock_bh(&ifmsh->sync_offset_lock);
197}
198
Johannes Berg8ba7acf2012-09-30 17:07:19 +0200199static const struct sync_method sync_methods[] = {
Javier Cardonadbf498f2012-03-31 11:31:32 -0700200 {
201 .method = IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET,
202 .ops = {
203 .rx_bcn_presp = &mesh_sync_offset_rx_bcn_presp,
Masashi Honma445cd452016-12-08 10:15:51 +0900204 .adjust_tsf = &mesh_sync_offset_adjust_tsf,
Javier Cardonadbf498f2012-03-31 11:31:32 -0700205 }
206 },
Javier Cardonadbf498f2012-03-31 11:31:32 -0700207};
208
Johannes Berg8ba7acf2012-09-30 17:07:19 +0200209const struct ieee80211_mesh_sync_ops *ieee80211_mesh_sync_ops_get(u8 method)
Javier Cardonadbf498f2012-03-31 11:31:32 -0700210{
Johannes Bergbf7cd942013-02-15 14:40:31 +0100211 int i;
Javier Cardonadbf498f2012-03-31 11:31:32 -0700212
213 for (i = 0 ; i < ARRAY_SIZE(sync_methods); ++i) {
Johannes Bergbf7cd942013-02-15 14:40:31 +0100214 if (sync_methods[i].method == method)
215 return &sync_methods[i].ops;
Javier Cardonadbf498f2012-03-31 11:31:32 -0700216 }
Johannes Bergbf7cd942013-02-15 14:40:31 +0100217 return NULL;
Javier Cardonadbf498f2012-03-31 11:31:32 -0700218}