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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
dbf498fb JC |
2 | /* |
3 | * Copyright 2011-2012, Pavel Zubarev <pavel.zubarev@gmail.com> | |
4 | * Copyright 2011-2012, Marco Porsch <marco.porsch@s2005.tu-chemnitz.de> | |
5 | * Copyright 2011-2012, cozybit Inc. | |
dbf498fb JC |
6 | */ |
7 | ||
8 | #include "ieee80211_i.h" | |
9 | #include "mesh.h" | |
10 | #include "driver-ops.h" | |
11 | ||
445cd452 | 12 | /* This is not in the standard. It represents a tolerable tsf drift below |
dbf498fb JC |
13 | * which we do no TSF adjustment. |
14 | */ | |
a802a6eb JC |
15 | #define TOFFSET_MINIMUM_ADJUSTMENT 10 |
16 | ||
ec14bcd2 JC |
17 | /* This is not in the standard. It is a margin added to the |
18 | * Toffset setpoint to mitigate TSF overcorrection | |
19 | * introduced by TSF adjustment latency. | |
20 | */ | |
21 | #define TOFFSET_SET_MARGIN 20 | |
22 | ||
a802a6eb JC |
23 | /* This is not in the standard. It represents the maximum Toffset jump above |
24 | * which we'll invalidate the Toffset setpoint and choose a new setpoint. This | |
25 | * could be, for instance, in case a neighbor is restarted and its TSF counter | |
26 | * reset. | |
ec14bcd2 | 27 | */ |
3a53731d | 28 | #define TOFFSET_MAXIMUM_ADJUSTMENT 800 /* 0.8 ms */ |
dbf498fb JC |
29 | |
30 | struct sync_method { | |
31 | u8 method; | |
32 | struct ieee80211_mesh_sync_ops ops; | |
33 | }; | |
34 | ||
35 | /** | |
36 | * mesh_peer_tbtt_adjusting - check if an mp is currently adjusting its TBTT | |
37 | * | |
38 | * @ie: information elements of a management frame from the mesh peer | |
39 | */ | |
40 | static bool mesh_peer_tbtt_adjusting(struct ieee802_11_elems *ie) | |
41 | { | |
42 | return (ie->mesh_config->meshconf_cap & | |
bf7cd94d | 43 | IEEE80211_MESHCONF_CAPAB_TBTT_ADJUSTING) != 0; |
dbf498fb JC |
44 | } |
45 | ||
445cd452 | 46 | void mesh_sync_adjust_tsf(struct ieee80211_sub_if_data *sdata) |
dbf498fb JC |
47 | { |
48 | struct ieee80211_local *local = sdata->local; | |
49 | struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; | |
50 | /* sdata->vif.bss_conf.beacon_int in 1024us units, 0.04% */ | |
51 | u64 beacon_int_fraction = sdata->vif.bss_conf.beacon_int * 1024 / 2500; | |
52 | u64 tsf; | |
53 | u64 tsfdelta; | |
54 | ||
55 | spin_lock_bh(&ifmsh->sync_offset_lock); | |
dbf498fb | 56 | if (ifmsh->sync_offset_clockdrift_max < beacon_int_fraction) { |
445cd452 | 57 | msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting\n", |
bdcbd8e0 | 58 | (long long) ifmsh->sync_offset_clockdrift_max); |
dbf498fb JC |
59 | tsfdelta = -ifmsh->sync_offset_clockdrift_max; |
60 | ifmsh->sync_offset_clockdrift_max = 0; | |
61 | } else { | |
445cd452 | 62 | msync_dbg(sdata, "TSF : max clockdrift=%lld; adjusting by %llu\n", |
bdcbd8e0 JB |
63 | (long long) ifmsh->sync_offset_clockdrift_max, |
64 | (unsigned long long) beacon_int_fraction); | |
dbf498fb JC |
65 | tsfdelta = -beacon_int_fraction; |
66 | ifmsh->sync_offset_clockdrift_max -= beacon_int_fraction; | |
67 | } | |
55fabefe | 68 | spin_unlock_bh(&ifmsh->sync_offset_lock); |
dbf498fb | 69 | |
354d381b PT |
70 | if (local->ops->offset_tsf) { |
71 | drv_offset_tsf(local, sdata, tsfdelta); | |
72 | } else { | |
73 | tsf = drv_get_tsf(local, sdata); | |
74 | if (tsf != -1ULL) | |
75 | drv_set_tsf(local, sdata, tsf + tsfdelta); | |
76 | } | |
dbf498fb JC |
77 | } |
78 | ||
79 | static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata, | |
80 | u16 stype, | |
81 | struct ieee80211_mgmt *mgmt, | |
82 | struct ieee802_11_elems *elems, | |
83 | struct ieee80211_rx_status *rx_status) | |
84 | { | |
85 | struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; | |
86 | struct ieee80211_local *local = sdata->local; | |
87 | struct sta_info *sta; | |
88 | u64 t_t, t_r; | |
89 | ||
90 | WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET); | |
91 | ||
92 | /* standard mentions only beacons */ | |
93 | if (stype != IEEE80211_STYPE_BEACON) | |
94 | return; | |
95 | ||
ce953204 BC |
96 | /* |
97 | * Get time when timestamp field was received. If we don't | |
98 | * have rx timestamps, then use current tsf as an approximation. | |
99 | * drv_get_tsf() must be called before entering the rcu-read | |
100 | * section. | |
101 | */ | |
102 | if (ieee80211_have_rx_timestamp(rx_status)) | |
103 | t_r = ieee80211_calculate_rx_timestamp(local, rx_status, | |
104 | 24 + 12 + | |
105 | elems->total_len + | |
106 | FCS_LEN, | |
107 | 24); | |
108 | else | |
109 | t_r = drv_get_tsf(local, sdata); | |
dbf498fb JC |
110 | |
111 | rcu_read_lock(); | |
112 | sta = sta_info_get(sdata, mgmt->sa); | |
113 | if (!sta) | |
114 | goto no_sync; | |
115 | ||
116 | /* check offset sync conditions (13.13.2.2.1) | |
117 | * | |
118 | * TODO also sync to | |
119 | * dot11MeshNbrOffsetMaxNeighbor non-peer non-MBSS neighbors | |
120 | */ | |
121 | ||
122 | if (elems->mesh_config && mesh_peer_tbtt_adjusting(elems)) { | |
bf7cd94d JB |
123 | msync_dbg(sdata, "STA %pM : is adjusting TBTT\n", |
124 | sta->sta.addr); | |
dbf498fb JC |
125 | goto no_sync; |
126 | } | |
127 | ||
dbf498fb JC |
128 | /* Timing offset calculation (see 13.13.2.2.2) */ |
129 | t_t = le64_to_cpu(mgmt->u.beacon.timestamp); | |
433f5bc1 | 130 | sta->mesh->t_offset = t_t - t_r; |
dbf498fb JC |
131 | |
132 | if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) { | |
433f5bc1 | 133 | s64 t_clockdrift = sta->mesh->t_offset_setpoint - sta->mesh->t_offset; |
bdcbd8e0 | 134 | msync_dbg(sdata, |
433f5bc1 JB |
135 | "STA %pM : t_offset=%lld, t_offset_setpoint=%lld, t_clockdrift=%lld\n", |
136 | sta->sta.addr, (long long) sta->mesh->t_offset, | |
137 | (long long) sta->mesh->t_offset_setpoint, | |
dbf498fb | 138 | (long long) t_clockdrift); |
a802a6eb JC |
139 | |
140 | if (t_clockdrift > TOFFSET_MAXIMUM_ADJUSTMENT || | |
bf7cd94d | 141 | t_clockdrift < -TOFFSET_MAXIMUM_ADJUSTMENT) { |
bdcbd8e0 JB |
142 | msync_dbg(sdata, |
143 | "STA %pM : t_clockdrift=%lld too large, setpoint reset\n", | |
a802a6eb JC |
144 | sta->sta.addr, |
145 | (long long) t_clockdrift); | |
146 | clear_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN); | |
147 | goto no_sync; | |
148 | } | |
149 | ||
dbf498fb | 150 | spin_lock_bh(&ifmsh->sync_offset_lock); |
bf7cd94d JB |
151 | if (t_clockdrift > ifmsh->sync_offset_clockdrift_max) |
152 | ifmsh->sync_offset_clockdrift_max = t_clockdrift; | |
dbf498fb | 153 | spin_unlock_bh(&ifmsh->sync_offset_lock); |
dbf498fb | 154 | } else { |
433f5bc1 | 155 | sta->mesh->t_offset_setpoint = sta->mesh->t_offset - TOFFSET_SET_MARGIN; |
dbf498fb | 156 | set_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN); |
bdcbd8e0 | 157 | msync_dbg(sdata, |
433f5bc1 | 158 | "STA %pM : offset was invalid, t_offset=%lld\n", |
dbf498fb | 159 | sta->sta.addr, |
433f5bc1 | 160 | (long long) sta->mesh->t_offset); |
dbf498fb | 161 | } |
dbf498fb JC |
162 | |
163 | no_sync: | |
164 | rcu_read_unlock(); | |
165 | } | |
166 | ||
445cd452 | 167 | static void mesh_sync_offset_adjust_tsf(struct ieee80211_sub_if_data *sdata, |
43552be1 | 168 | struct beacon_data *beacon) |
dbf498fb JC |
169 | { |
170 | struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; | |
171 | ||
bf7cd94d | 172 | WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET); |
8c5bb1fa | 173 | WARN_ON(!rcu_read_lock_held()); |
dbf498fb JC |
174 | |
175 | spin_lock_bh(&ifmsh->sync_offset_lock); | |
176 | ||
bf7cd94d | 177 | if (ifmsh->sync_offset_clockdrift_max > TOFFSET_MINIMUM_ADJUSTMENT) { |
dbf498fb JC |
178 | /* Since ajusting the tsf here would |
179 | * require a possibly blocking call | |
180 | * to the driver tsf setter, we punt | |
181 | * the tsf adjustment to the mesh tasklet | |
182 | */ | |
bdcbd8e0 | 183 | msync_dbg(sdata, |
445cd452 | 184 | "TSF : kicking off TSF adjustment with clockdrift_max=%lld\n", |
bdcbd8e0 | 185 | ifmsh->sync_offset_clockdrift_max); |
bf7cd94d | 186 | set_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags); |
dbf498fb | 187 | } else { |
bdcbd8e0 | 188 | msync_dbg(sdata, |
445cd452 | 189 | "TSF : max clockdrift=%lld; too small to adjust\n", |
bdcbd8e0 | 190 | (long long)ifmsh->sync_offset_clockdrift_max); |
dbf498fb JC |
191 | ifmsh->sync_offset_clockdrift_max = 0; |
192 | } | |
193 | spin_unlock_bh(&ifmsh->sync_offset_lock); | |
194 | } | |
195 | ||
8ba7acf3 | 196 | static const struct sync_method sync_methods[] = { |
dbf498fb JC |
197 | { |
198 | .method = IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET, | |
199 | .ops = { | |
200 | .rx_bcn_presp = &mesh_sync_offset_rx_bcn_presp, | |
445cd452 | 201 | .adjust_tsf = &mesh_sync_offset_adjust_tsf, |
dbf498fb JC |
202 | } |
203 | }, | |
dbf498fb JC |
204 | }; |
205 | ||
8ba7acf3 | 206 | const struct ieee80211_mesh_sync_ops *ieee80211_mesh_sync_ops_get(u8 method) |
dbf498fb | 207 | { |
bf7cd94d | 208 | int i; |
dbf498fb JC |
209 | |
210 | for (i = 0 ; i < ARRAY_SIZE(sync_methods); ++i) { | |
bf7cd94d JB |
211 | if (sync_methods[i].method == method) |
212 | return &sync_methods[i].ops; | |
dbf498fb | 213 | } |
bf7cd94d | 214 | return NULL; |
dbf498fb | 215 | } |