1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
|
/* ASCI (VGCS/VBS) related common code */
/* (C) 2023 by Harald Welte <laforge@osmocom.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/rsl.h>
#include <osmo-bts/bts.h>
#include <osmo-bts/bts_model.h>
#include <osmo-bts/rsl.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/l1sap.h>
#include <osmo-bts/asci.h>
static int tx_vgcs_ul_grant(struct gsm_lchan *lchan)
{
struct gsm0408_vgcs_ul_grant ul_grant;
struct gsm_time gt;
struct msgb *msg;
gsm_fn2gsmtime(>, lchan->asci.fn);
/* build the RR VGCS UPLINK GRANT message as per TS 44.018 Section 9.1.49 */
ul_grant = (struct gsm0408_vgcs_ul_grant) {
.hdr = {
.proto_discr = GSM48_PDISC_RR,
.msg_type = GSM48_MT_RR_VGCS_UPL_GRANT,
},
.req_ref = {
.ra = lchan->asci.ref,
.t1 = gt.t1,
.t2 = gt.t2,
.t3_low = gt.t3 & 7,
.t3_high = gt.t3 >> 3,
},
.ta = lchan->ta_ctrl.current,
};
/* Wrap it in a RSL UNITDATA REQUEST */
msg = rsl_rll_simple(RSL_MT_UNIT_DATA_REQ, gsm_lchan2chan_nr(lchan), 0x00, 0);
msg->l3h = msg->tail; /* emulate rsl_rx_rll() behaviour */
msgb_tl16v_put(msg, RSL_IE_L3_INFO, sizeof(ul_grant), (uint8_t *) &ul_grant);
/* send it towards MS, just like a RSL message from the BSC */
return lapdm_rslms_recvmsg(msg, &lchan->lapdm_ch);
}
/* timer call-back for T3115 (VGCS UPLINK GRANT re-transmit) */
static void vgcs_t3115_cb(void *data)
{
struct gsm_lchan *lchan = data;
struct gsm_bts *bts = lchan->ts->trx->bts;
LOGPLCHAN(lchan, DASCI, LOGL_INFO, "T3115 timeout (%d resends left)\n",
bts->ny2 - lchan->asci.vgcs_ul_grant_count);
if (lchan->state != LCHAN_S_ACTIVE) {
LOGPLCHAN(lchan, DASCI, LOGL_NOTICE, "is not active. It is in state %s. Ignoring\n",
gsm_lchans_name(lchan->state));
return;
}
if (lchan->asci.vgcs_ul_grant_count >= bts->ny2) {
lchan->asci.vgcs_ul_grant_count = 0;
LOGPLCHAN(lchan, DASCI, LOGL_NOTICE, "NY2 reached, sending CONNection FAILure to BSC.\n");
rsl_tx_conn_fail(lchan, RSL_ERR_TALKER_ACC_FAIL);
lchan->asci.talker_active = VGCS_TALKER_NONE;
return;
}
tx_vgcs_ul_grant(lchan);
lchan->asci.vgcs_ul_grant_count++;
osmo_timer_schedule(&lchan->asci.t3115, 0, bts->t3115_ms * 1000);
}
/* Received random access on dedicated channel. */
void vgcs_rach(struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay, uint32_t fn)
{
LOGPLCHAN(lchan, DASCI, LOGL_NOTICE, "VGCS RACH on dedicated channel type %s received with "
"TA=%u, ref=%u\n", gsm_lchant_name(lchan->type), acc_delay, ra);
if (ra == 0x25) { /* See TS 44.018 Table 9.1.45.1 */
/* Listener Detection (TS 48.058 Section 4.14) */
if (!lchan->asci.listener_detected) {
rsl_tx_listener_det(lchan, &acc_delay);
lchan->asci.listener_detected = true;
}
} else {
/* Talker Detection (TS 48.058 Section 4.13) */
struct gsm_bts *bts = lchan->ts->trx->bts;
/* Talker detection on group channels only */
if (!rsl_chan_rt_is_vgcs(lchan->rsl_chan_rt))
return;
if (lchan->asci.talker_active != VGCS_TALKER_NONE) {
LOGPLCHAN(lchan, DASCI, LOGL_DEBUG, "Ignoring RACH, there is an active talker already.\n");
return;
}
/* Set timing advance, power level and activate SACCH */
lchan->ta_ctrl.current = acc_delay;
lchan->ms_power_ctrl.current = lchan->ms_power_ctrl.max;
lchan->want_dl_sacch_active = true;
/* Stop RACH detection, wait for valid frame */
lchan->asci.talker_active = VGCS_TALKER_WAIT_FRAME;
if (l1sap_uplink_access(lchan, false) != 0) {
LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "Failed to deactivate uplink access after TALKER DET.\n");
rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
lchan->asci.talker_active = VGCS_TALKER_NONE;
return;
}
lchan->asci.ref = ra;
lchan->asci.fn = fn;
/* Send TALKER DETECT via RSL to BSC */
rsl_tx_talker_det(lchan, &acc_delay);
/* Send VGCS UPLINK GRANT */
lchan->asci.vgcs_ul_grant_count = 1;
tx_vgcs_ul_grant(lchan);
/* Start T3115 */
LOGPLCHAN(lchan, DASCI, LOGL_DEBUG, "Starting T3115 with %u ms\n", bts->t3115_ms);
lchan->asci.t3115.cb = vgcs_t3115_cb;
lchan->asci.t3115.data = lchan;
osmo_timer_schedule(&lchan->asci.t3115, 0, bts->t3115_ms * 1000);
}
}
/* Received channel activation. */
void vgcs_lchan_activate(struct gsm_lchan *lchan)
{
LOGPLCHAN(lchan, DASCI, LOGL_INFO, "Channel is activated.\n");
if (l1sap_uplink_access(lchan, true) != 0) {
LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "Failed to activate uplink access after channel activation.\n");
rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
}
}
/* Received channel reactivation. (for assignment) */
void vgcs_lchan_react(struct gsm_lchan *lchan)
{
LOGPLCHAN(lchan, DASCI, LOGL_INFO, "Channel is activated for assignment.\n");
lchan->asci.talker_active = VGCS_TALKER_WAIT_FRAME;
if (l1sap_uplink_access(lchan, false) != 0) {
LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "Failed to deactivate uplink access for assignment.\n");
rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
}
radio_link_timeout_reset(lchan);
}
/* Received first valid data frame on dedicated channel. */
void vgcs_talker_frame(struct gsm_lchan *lchan)
{
LOGPLCHAN(lchan, DASCI, LOGL_INFO, "First valid frame detected, talker now active.\n");
osmo_timer_del(&lchan->asci.t3115);
lchan->asci.talker_active = VGCS_TALKER_ACTIVE;
radio_link_timeout_reset(lchan);
}
/* Release VGCS Talker state. */
void vgcs_talker_reset(struct gsm_lchan *lchan, bool ul_access)
{
if (lchan->asci.talker_active == VGCS_TALKER_NONE)
return;
LOGPLCHAN(lchan, DASCI, LOGL_INFO, "Uplink released, no talker.\n");
/* Stop T3115 */
osmo_timer_del(&lchan->asci.t3115);
/* Talker released. */
lchan->asci.talker_active = VGCS_TALKER_NONE;
if (ul_access) {
if (l1sap_uplink_access(lchan, true) != 0) {
LOGPLCHAN(lchan, DASCI, LOGL_ERROR,
"Failed to activate uplink access after uplink became free.\n");
rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
}
}
}
/* Release VGCS Listener state. */
void vgcs_listener_reset(struct gsm_lchan *lchan)
{
lchan->asci.listener_detected = false;
}
|
