summaryrefslogtreecommitdiffstats
path: root/src/gsmtap_util.c
blob: 954586576ee9c2aa0aab573b7471946a02b68de9 (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
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
/* GSMTAP support code in libmsomcore */
/*
 * (C) 2010-2011 by Harald Welte <laforge@gnumonks.org>
 *
 * 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 "../config.h"

#include <osmocom/core/gsmtap_util.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/gsmtap.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/select.h>
#include <osmocom/core/socket.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/rsl.h>

#include <sys/types.h>

#include <arpa/inet.h>

#include <stdio.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>

uint8_t chantype_rsl2gsmtap(uint8_t rsl_chantype, uint8_t link_id)
{
	uint8_t ret = GSMTAP_CHANNEL_UNKNOWN;

	switch (rsl_chantype) {
	case RSL_CHAN_Bm_ACCHs:
		ret = GSMTAP_CHANNEL_TCH_F;
		break;
	case RSL_CHAN_Lm_ACCHs:
		ret = GSMTAP_CHANNEL_TCH_H;
		break;
	case RSL_CHAN_SDCCH4_ACCH:
		ret = GSMTAP_CHANNEL_SDCCH4;
		break;
	case RSL_CHAN_SDCCH8_ACCH:
		ret = GSMTAP_CHANNEL_SDCCH8;
		break;
	case RSL_CHAN_BCCH:
		ret = GSMTAP_CHANNEL_BCCH;
		break;
	case RSL_CHAN_RACH:
		ret = GSMTAP_CHANNEL_RACH;
		break;
	case RSL_CHAN_PCH_AGCH:
		/* it could also be AGCH... */
		ret = GSMTAP_CHANNEL_PCH;
		break;
	}

	if (link_id & 0x40)
		ret |= GSMTAP_CHANNEL_ACCH;

	return ret;
}

/* receive a message from L1/L2 and put it in GSMTAP */
struct msgb *gsmtap_makemsg(uint16_t arfcn, uint8_t ts, uint8_t chan_type,
			    uint8_t ss, uint32_t fn, int8_t signal_dbm,
			    uint8_t snr, const uint8_t *data, unsigned int len)
{
	struct msgb *msg;
	struct gsmtap_hdr *gh;
	uint8_t *dst;

	msg = msgb_alloc(sizeof(*gh) + len, "gsmtap_tx");
	if (!msg)
		return NULL;

	gh = (struct gsmtap_hdr *) msgb_put(msg, sizeof(*gh));

	gh->version = GSMTAP_VERSION;
	gh->hdr_len = sizeof(*gh)/4;
	gh->type = GSMTAP_TYPE_UM;
	gh->timeslot = ts;
	gh->sub_slot = ss;
	gh->arfcn = htons(arfcn);
	gh->snr_db = snr;
	gh->signal_dbm = signal_dbm;
	gh->frame_number = htonl(fn);
	gh->sub_type = chan_type;
	gh->antenna_nr = 0;

	dst = msgb_put(msg, len);
	memcpy(dst, data, len);

	return msg;
}

#ifdef HAVE_SYS_SOCKET_H

#include <sys/socket.h>
#include <netinet/in.h>

/* Open a GSMTAP source (sending) socket, conncet it to host/port and
 * return resulting fd */
int gsmtap_source_init_fd(const char *host, uint16_t port)
{
	if (port == 0)
		port = GSMTAP_UDP_PORT;
	if (host == NULL)
		host = "localhost";

	return osmo_sock_init(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, host, port, 0);
}

int gsmtap_source_add_sink_fd(int gsmtap_fd)
{
	struct sockaddr_storage ss;
	socklen_t ss_len = sizeof(ss);
	int rc;

	rc = getpeername(gsmtap_fd, (struct sockaddr *)&ss, &ss_len);
	if (rc < 0)
		return rc;

	if (osmo_sockaddr_is_local((struct sockaddr *)&ss, ss_len) == 1) {
		rc = osmo_sock_init_sa((struct sockaddr *)&ss, SOCK_DGRAM, IPPROTO_UDP, 1);
		if (rc >= 0)
			return rc;
	}

	return -ENODEV;
}

int gsmtap_sendmsg(struct gsmtap_inst *gti, struct msgb *msg)
{
	if (!gti)
		return -ENODEV;

	if (gti->ofd_wq_mode)
		return osmo_wqueue_enqueue(&gti->wq, msg);
	else {
		/* try immediate send and return error if any */
		int rc;

		rc = write(gsmtap_inst_fd(gti), msg->data, msg->len);
		if (rc <= 0) {
			return rc;
		} else if (rc >= msg->len) {
			msgb_free(msg);
			return 0;
		} else {
			/* short write */
			return -EIO;
		}
	}
}

/* receive a message from L1/L2 and put it in GSMTAP */
int gsmtap_send(struct gsmtap_inst *gti, uint16_t arfcn, uint8_t ts,
		uint8_t chan_type, uint8_t ss, uint32_t fn,
		int8_t signal_dbm, uint8_t snr, const uint8_t *data,
		unsigned int len)
{
	struct msgb *msg;

	if (!gti)
		return -ENODEV;

	msg = gsmtap_makemsg(arfcn, ts, chan_type, ss, fn, signal_dbm,
			     snr, data, len);
	if (!msg)
		return -ENOMEM;

	return gsmtap_sendmsg(gti, msg);
}

/* Callback from select layer if we can write to the socket */
static int gsmtap_wq_w_cb(struct osmo_fd *ofd, struct msgb *msg)
{
	int rc;

	rc = write(ofd->fd, msg->data, msg->len);
	if (rc < 0) {
		perror("writing msgb to gsmtap fd");
		return rc;
	}
	if (rc != msg->len) {
		perror("short write to gsmtap fd");
		return -EIO;
	}

	return 0;
}

/* Callback from select layer if we can read from the sink socket */
static int gsmtap_sink_fd_cb(struct osmo_fd *fd, unsigned int flags)
{
	int rc;
	uint8_t buf[4096];

	if (!(flags & BSC_FD_READ))
		return 0;

	rc = read(fd->fd, buf, sizeof(buf));
	if (rc < 0) {
		perror("reading from gsmtap sink fd");
		return rc;
	}
	/* simply discard any data arriving on the socket */

	return 0;
}

/* Add a local sink to an existing GSMTAP source instance */
int gsmtap_source_add_sink(struct gsmtap_inst *gti)
{
	int fd;

	fd = gsmtap_source_add_sink_fd(gsmtap_inst_fd(gti));
	if (fd < 0)
		return fd;

	if (gti->ofd_wq_mode) {
		struct osmo_fd *sink_ofd;

		sink_ofd = &gti->sink_ofd;
		sink_ofd->fd = fd;
		sink_ofd->when = BSC_FD_READ;
		sink_ofd->cb = gsmtap_sink_fd_cb;

		osmo_fd_register(sink_ofd);
	}

	return fd;
}

/* like gsmtap_init2() but integrated with libosmocore select.c */
struct gsmtap_inst *gsmtap_source_init(const char *host, uint16_t port,
					int ofd_wq_mode)
{
	struct gsmtap_inst *gti;
	int fd;

	fd = gsmtap_source_init_fd(host, port);
	if (fd < 0)
		return NULL;

	gti = talloc_zero(NULL, struct gsmtap_inst);
	gti->ofd_wq_mode = ofd_wq_mode;
	gti->wq.bfd.fd = fd;
	gti->sink_ofd.fd = -1;

	if (ofd_wq_mode) {
		osmo_wqueue_init(&gti->wq, 64);
		gti->wq.write_cb = &gsmtap_wq_w_cb;

		osmo_fd_register(&gti->wq.bfd);
	}

	return gti;
}

#endif /* HAVE_SYS_SOCKET_H */