summaryrefslogtreecommitdiffstats
path: root/src/host/layer23/src/misc/app_cbch_sniff.c
blob: a62dd7c9214930988a1d4f1cdd69b0d6aabd5f8d (plain)
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
/* CBCH passive sniffer */

/* (C) 2010 by Holger Hans Peter Freyther
 * (C) 2010 by Harald Welte <laforge@gnumonks.org>
 * (C) 2010 by Alex Badea <vamposdecampos@gmail.com>
 *
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <osmocom/bb/common/osmocom_data.h>
#include <osmocom/bb/common/l1ctl.h>
#include <osmocom/bb/common/logging.h>
#include <osmocom/bb/common/l23_app.h>
#include <osmocom/bb/misc/layer3.h>

#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/select.h>
#include <osmocom/core/signal.h>
#include <osmocom/gsm/rsl.h>

#include <l1ctl_proto.h>

struct osmocom_ms *g_ms;
struct gsm48_sysinfo g_sysinfo = {};

static int try_cbch(struct osmocom_ms *ms, struct gsm48_sysinfo *s)
{
	if (!s->si1 || !s->si4)
		return 0;
	if (!s->chan_nr) {
		LOGP(DRR, LOGL_INFO, "no CBCH chan_nr found\n");
		return 0;
	}

	if (s->h) {
		LOGP(DRR, LOGL_INFO, "chan_nr = 0x%02x TSC = %d  MAIO = %d  "
			"HSN = %d  hseq (%d): %s\n",
			s->chan_nr, s->tsc, s->maio, s->hsn,
			s->hopp_len,
			osmo_hexdump((unsigned char *) s->hopping, s->hopp_len * 2));
		return l1ctl_tx_dm_est_req_h1(ms,
			s->maio, s->hsn, s->hopping, s->hopp_len,
			s->chan_nr, s->tsc,
			GSM48_CMODE_SIGN, 0, L1CTL_DM_F_CBCH);
	} else {
		LOGP(DRR, LOGL_INFO, "chan_nr = 0x%02x TSC = %d  ARFCN = %d\n",
			s->chan_nr, s->tsc, s->arfcn);
		return l1ctl_tx_dm_est_req_h0(ms, s->arfcn,
			s->chan_nr, s->tsc, GSM48_CMODE_SIGN, 0, L1CTL_DM_F_CBCH);
	}
}


/* receive BCCH at RR layer */
static int bcch(struct osmocom_ms *ms, struct msgb *msg)
{
	struct gsm48_system_information_type_header *sih = msgb_l3(msg);
	struct gsm48_sysinfo *s = &g_sysinfo;

	if (msgb_l3len(msg) != 23) {
		LOGP(DRR, LOGL_NOTICE, "Invalid BCCH message length\n");
		return -EINVAL;
	}
	switch (sih->system_information) {
	case GSM48_MT_RR_SYSINFO_1:
		LOGP(DRR, LOGL_INFO, "New SYSTEM INFORMATION 1\n");
		gsm48_decode_sysinfo1(s,
			(struct gsm48_system_information_type_1 *) sih,
			msgb_l3len(msg));
		return try_cbch(ms, s);
	case GSM48_MT_RR_SYSINFO_4:
		LOGP(DRR, LOGL_INFO, "New SYSTEM INFORMATION 4\n");
		gsm48_decode_sysinfo4(s,
			(struct gsm48_system_information_type_4 *) sih,
			msgb_l3len(msg));
		return try_cbch(ms, s);
	default:
		return 0;
	}
}

static int unit_data_ind(struct osmocom_ms *ms, struct msgb *msg)
{
	struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
	struct tlv_parsed tv;
	uint8_t ch_type, ch_subch, ch_ts;

	DEBUGP(DRSL, "RSLms UNIT DATA IND chan_nr=0x%02x link_id=0x%02x\n",
		rllh->chan_nr, rllh->link_id);

	rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh));
	if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) {
		DEBUGP(DRSL, "UNIT_DATA_IND without L3 INFO ?!?\n");
		return -EIO;
	}
	msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO);

	rsl_dec_chan_nr(rllh->chan_nr, &ch_type, &ch_subch, &ch_ts);
	switch (ch_type) {
	case RSL_CHAN_BCCH:
		return bcch(ms, msg);
	default:
		return 0;
	}
}

static int rcv_rll(struct osmocom_ms *ms, struct msgb *msg)
{
	struct abis_rsl_rll_hdr *rllh = msgb_l2(msg);
	int msg_type = rllh->c.msg_type;

	if (msg_type == RSL_MT_UNIT_DATA_IND) {
		unit_data_ind(ms, msg);
	} else
		LOGP(DRSL, LOGL_NOTICE, "RSLms message unhandled\n");

	msgb_free(msg);

	return 0;
}

static int rcv_rsl(struct msgb *msg, struct lapdm_entity *le, void *l3ctx)
{
	struct osmocom_ms *ms = l3ctx;
	struct abis_rsl_common_hdr *rslh = msgb_l2(msg);
	int rc = 0;

	switch (rslh->msg_discr & 0xfe) {
	case ABIS_RSL_MDISC_RLL:
		rc = rcv_rll(ms, msg);
		break;
	default:
		LOGP(DRSL, LOGL_NOTICE, "unknown RSLms msg_discr 0x%02x\n",
			rslh->msg_discr);
		msgb_free(msg);
		rc = -EINVAL;
		break;
	}

	return rc;
}

static int signal_cb(unsigned int subsys, unsigned int signal,
		     void *handler_data, void *signal_data)
{
	struct osmocom_ms *ms;

	if (subsys != SS_L1CTL)
		return 0;

	switch (signal) {
	case S_L1CTL_RESET:
	case S_L1CTL_FBSB_ERR:
		ms = g_ms;
		return l1ctl_tx_fbsb_req(ms, ms->test_arfcn,
			L1CTL_FBSB_F_FB01SB, 100, 0, CCCH_MODE_COMBINED,
			dbm2rxlev(-85));
	case S_L1CTL_FBSB_RESP:
		return 0;
	}
	return 0;
}

int l23_app_init(struct osmocom_ms *ms)
{
	/* don't do layer3_init() as we don't want an actualy L3 */

	g_ms = ms;
	lapdm_channel_set_l3(&ms->lapdm_channel, &rcv_rsl, ms);

	l1ctl_tx_reset_req(ms, L1CTL_RES_T_FULL);
	/* FIXME: L1CTL_RES_T_FULL doesn't reset dedicated mode
	 * (if previously set), so we release it here. */
	l1ctl_tx_dm_rel_req(ms);
	return osmo_signal_register_handler(SS_L1CTL, &signal_cb, NULL);
}

static struct l23_app_info info = {
	.copyright	= "Copyright (C) 2010 Harald Welte <laforge@gnumonks.org>\n",
	.contribution	= "Contributions by Holger Hans Peter Freyther\n",
};

struct l23_app_info *l23_app_info()
{
	return &info;
}