aboutsummaryrefslogtreecommitdiffstats
path: root/net/mac80211/mesh_sync.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/mac80211/mesh_sync.c')
-rw-r--r--net/mac80211/mesh_sync.c44
1 files changed, 7 insertions, 37 deletions
diff --git a/net/mac80211/mesh_sync.c b/net/mac80211/mesh_sync.c
index 407c8705e10d..9c6ea9cfe1b3 100644
--- a/net/mac80211/mesh_sync.c
+++ b/net/mac80211/mesh_sync.c
@@ -116,43 +116,13 @@ static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
116 goto no_sync; 116 goto no_sync;
117 } 117 }
118 118
119 if (rx_status->flag & RX_FLAG_MACTIME_MPDU && rx_status->mactime) { 119 if (ieee80211_have_rx_timestamp(rx_status))
120 /* 120 /* time when timestamp field was received */
121 * The mactime is defined as the time the first data symbol 121 t_r = ieee80211_calculate_rx_timestamp(local, rx_status,
122 * of the frame hits the PHY, and the timestamp of the beacon 122 24 + 12 +
123 * is defined as "the time that the data symbol containing the 123 elems->total_len +
124 * first bit of the timestamp is transmitted to the PHY plus 124 FCS_LEN,
125 * the transmitting STA's delays through its local PHY from the 125 24);
126 * MAC-PHY interface to its interface with the WM" (802.11
127 * 11.1.2)
128 *
129 * T_r, in 13.13.2.2.2, is just defined as "the frame reception
130 * time" but we unless we interpret that time to be the same
131 * time of the beacon timestamp, the offset calculation will be
132 * off. Below we adjust t_r to be "the time at which the first
133 * symbol of the timestamp element in the beacon is received".
134 * This correction depends on the rate.
135 *
136 * Based on similar code in ibss.c
137 */
138 int rate;
139
140 if (rx_status->flag & RX_FLAG_HT) {
141 /* TODO:
142 * In principle there could be HT-beacons (Dual Beacon
143 * HT Operation options), but for now ignore them and
144 * just use the primary (i.e. non-HT) beacons for
145 * synchronization.
146 * */
147 goto no_sync;
148 } else
149 rate = local->hw.wiphy->bands[rx_status->band]->
150 bitrates[rx_status->rate_idx].bitrate;
151
152 /* 24 bytes of header * 8 bits/byte *
153 * 10*(100 Kbps)/Mbps / rate (100 Kbps)*/
154 t_r = rx_status->mactime + (24 * 8 * 10 / rate);
155 }
156 126
157 /* Timing offset calculation (see 13.13.2.2.2) */ 127 /* Timing offset calculation (see 13.13.2.2.2) */
158 t_t = le64_to_cpu(mgmt->u.beacon.timestamp); 128 t_t = le64_to_cpu(mgmt->u.beacon.timestamp);