aboutsummaryrefslogtreecommitdiffstats
path: root/openbsc/src/osmo-ganc/ganc_server.c
blob: d447552baa9e5dac82da65a40504fe88f6ff0fc0 (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
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
/* Handling of actual UMA/GAN protocol as per TS 44.318 */

/* (C) 2012 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 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 <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <assert.h>

#include <arpa/inet.h>

#include <osmocom/core/socket.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/timer.h>
#include <osmocom/gsm/tlv.h>
#include <osmocom/gsm/protocol/gsm_44_318.h>
#include <osmocom/gsm/gan.h>
#include <osmocom/gsm/gsm48.h>

#include "conn.h"
#include "ganc_data.h"

static struct tlv_definition tlv_att_def;

static void push_rc_csr_hdr(struct msgb *msg, uint8_t pdisc, uint8_t msgt)
{
	struct gan_rc_csr_hdr *gh = 
		(struct gan_rc_csr_hdr *) msgb_push(msg, sizeof(*gh));

	gh->pdisc = pdisc;
	gh->msg_type = msgt;
}

static void gan_peer_destroy(struct gan_peer *peer)
{
	if (!peer)
		return;

	osmo_timer_del(&peer->keepalive_timer);
	llist_del(&peer->entry);
	talloc_free(peer);
}

static struct msgb *unc_msgb_alloc(void)
{
	return msgb_alloc_headroom(1024+128, 128, "GANC Tx");
}

static int unc_peer_tx(struct gan_peer *peer, struct msgb *msg)
{
	struct gan_rc_csr_hdr *gh = (struct gan_rc_csr_hdr*) msg->data;

	/* compute and fill-in length */
	msg->l2h = msg->data;
	gh->len = htons(msgb_l2len(msg)-2);

	if (peer->gan_release == 0) {
		/* shomehow old pre-GAN UMA doesn't have RC */
		if (gh->pdisc == GA_PDISC_RC)
			gh->pdisc = GA_PDISC_CSR;
	}
	
	return osmo_conn_enqueue(peer->conn, msg);
}

static uint8_t *msgb_tlv_be16_put(struct msgb *msg, uint8_t tag, uint16_t val)
{
	uint16_t _val = htons(val);
	return msgb_tlv_put(msg, tag, 2, (uint8_t *) &_val);
}

static void build_gan_cch_desc(struct gan_cch_desc_ie *ie, struct ganc_bts *bts)
{
	struct ganc_net *net = bts->net;

	/* properly initialize to zero */
	memset(ie, 0, sizeof(*ie));

	ie->ecmc = 0;	/* Early Classmark allowed */
	ie->nmo = 0;	/* NMO 1 */
	if (net->gprs.mode != 0)
		ie->gprs = 0;
	else
		ie->gprs = 1;	/* No GPRS */
	ie->dtm = 0;	/* No Dual Transfer Mode */
	ie->att = 1;	/* IMSI attach/detach shall be used */
#if 0
	ie->mscr = 1;	/* Release 99 onwards */
#else
	ie->mscr = 0;	/* To avoid problems with 2-bit sequence number */
#endif
	ie->t3212 = net->timer[T3212];
	ie->rac = bts->routing_area_code;
	ie->sgsnr = 1;	/* Release 99 onwards */
	ie->ecmp = net->emergency_gan_preferred;
	ie->re = 1;	/* No call re-esetablishment */
	ie->pfcfm = 0;	/* No PFC */
	ie->tgecs = 1;	/* Permit UTRAN classmark change */
	if (!net->emergency_gan_preferred)
		ie->access_class[0] |= 0x4; /* No emergency calls */
}

/* FIXME: move to libosmocore */
static void gsm48_cell_desc(struct gsm48_cell_desc *cd, uint8_t bsic, uint16_t arfcn)
{
	cd->ncc = (bsic >> 3) & 0x07;
	cd->bcc = bsic & 0x07;
	cd->arfcn_hi = arfcn >> 8;
	cd->arfcn_lo = arfcn & 0xff;
}

/* 10.1.6: GA-RC REGISTER ACCEPT */
static int tx_unc_reg_acc(struct gan_peer *peer)
{
	struct msgb *msg = unc_msgb_alloc();
	struct gsm48_loc_area_id lai;
	struct gsm48_cell_desc cd;
	struct gan_cch_desc_ie ie;
	struct ganc_bts *bts = peer->bts;
	struct ganc_net *net = bts->net;
	uint8_t gan_band = 0x02; /* GSM 1800 */

	printf("<- GA-RC REGISTER ACCEPT\n");

	if (!msg)
		return -ENOMEM;

	gsm48_cell_desc(&cd, bts->bsic, bts->arfcn);
	gsm48_generate_lai(&lai, net->country_code, net->network_code,
			   bts->location_area_code);
	build_gan_cch_desc(&ie, bts);

	push_rc_csr_hdr(msg, GA_PDISC_RC, GA_MT_RC_REGISTER_ACCEPT);

	msgb_tlv_be16_put(msg, GA_IE_GERAN_CELL_ID, bts->cell_identity);
	msgb_tlv_put(msg, GA_IE_LAC, sizeof(lai), (uint8_t *) &lai);
	msgb_tlv_put(msg, GA_IE_GANC_CTRL_CH_DESC, sizeof(ie), (uint8_t *) &ie);
	msgb_tlv_be16_put(msg, GA_IE_TU3910_TIMER, net->timer[TU3910]);
	msgb_tlv_be16_put(msg, GA_IE_TU3906_TIMER, net->timer[TU3906]);
	msgb_tlv_put(msg, GA_IE_GAN_BAND, 1, &gan_band);
	msgb_tlv_be16_put(msg, GA_IE_TU3920_TIMER, net->timer[TU3920]);
	msgb_tlv_put(msg, GA_IE_GANC_CELL_DESC, sizeof(cd), (uint8_t *) &cd);

	if (net->gprs.mode != 0) {
		msgb_tlv_be16_put(msg, GA_IE_TU4001_TIMER, net->timer[TU4001]);
		msgb_tlv_be16_put(msg, GA_IE_TU4003_TIMER, net->timer[TU4003]);
	}

	return unc_peer_tx(peer, msg);
}

static int push_fqdn_or_ip(struct msgb *msg, const char *host,
			   uint8_t fqdn_att, uint8_t ip_att)
{
	struct in_addr ia;
	int rc;

	rc = inet_aton(host, &ia);
	if (rc == 0) {
		/* it is not an IP address */
		msgb_tlv_put(msg, fqdn_att, strlen(host)+1,
			     (uint8_t *) host);
	} else {
		uint8_t buf[5];

		buf[0] = 0x21; /* Type: IPv4 */
		memcpy(buf+1, &ia, 4);
		msgb_tlv_put(msg, ip_att, sizeof(buf), buf);
	}

	return rc;
}

static struct ganc_bts *select_bts(struct gan_peer *peer)
{
	/* FIXME: we need to select the virtual BTS based on MAC address
	 * and/or ESSID of the AP */

	return g_ganc_bts;
}

/* 10.1.3: GA-RC DISCOVERY ACCEPT */
static int tx_unc_disco_acc(struct gan_peer *peer, const char *segw_host,
			    const char *ganc_host)
{
	struct msgb *msg = unc_msgb_alloc();

	printf("<- GA-RC DISCOVERY ACCEPT\n");

	if (!msg)
		return -ENOMEM;

	push_rc_csr_hdr(msg, GA_PDISC_RC, GA_MT_RC_DISCOVERY_ACCEPT);
	push_fqdn_or_ip(msg, segw_host,
			GA_IE_DEF_SEGW_FQDN, GA_IE_DEF_SEGW_IP);
	push_fqdn_or_ip(msg, ganc_host,
			GA_IE_DEF_GANC_FQDN, GA_IE_DEF_GANC_IP);

	return unc_peer_tx(peer, msg);
}

/* 10.1.25 GA-CSR DOWNLINK DIRECT TRANSFER */
static int tx_csr_dl_direct_xfer(struct gan_peer *peer, struct msgb *msg)
{
	printf("<- GA-CSR DL DIRECT TRANSFER\n");

	/* tag and length of L3 info */
	assert(msgb_l3len(msg) <= 255);
	msgb_tv_push(msg, GA_IE_L3_MSG, msgb_l3len(msg));

	push_rc_csr_hdr(msg, GA_PDISC_CSR, GA_MT_CSR_DL_DIRECT_XFER);

	return unc_peer_tx(peer, msg);
}

/* 10.1.19 GA-CSR RELEASE */

static int tx_csr_release(struct gan_peer *peer, uint8_t cause)
{
	struct msgb *msg = unc_msgb_alloc();

	printf("<- GA-CSR RELEASE\n");

	if (!msg)
		return -ENOMEM;

	push_rc_csr_hdr(msg, GA_PDISC_CSR, GA_MT_CSR_RELEASE);
	msgb_tlv_put(msg, GA_IE_RR_CAUSE, 1, &cause);

	return unc_peer_tx(peer, msg);
}

/* 10.1.21 GA-CSR PAGING REQUEST */
static int tx_csr_paging_req(struct gan_peer *peer, uint8_t mi_len,
			     uint8_t *mi, uint8_t chan_needed)
{
	struct msgb *msg = unc_msgb_alloc();

	printf("<- GA-CSR PAGING REQ\n");

	if (!msg)
		return -ENOMEM;

	push_rc_csr_hdr(msg, GA_PDISC_CSR, GA_MT_CSR_PAGING_REQ);
	msgb_tlv_put(msg, GA_IE_CHAN_NEEDED, 1, &chan_needed);
	msgb_tlv_put(msg, GA_IE_MI, mi_len, mi);

	return unc_peer_tx(peer, msg);
}

/* 10.1.13 GA-CSR REQUEST ACCEPT */
static int tx_csr_request_acc(struct gan_peer *peer)
{
	struct msgb *msg = unc_msgb_alloc();

	printf("<- GA-CSR REQUEST ACCEPT\n");

	if (!msg)
		return -ENOMEM;

	push_rc_csr_hdr(msg, GA_PDISC_CSR, GA_MT_CSR_REQUEST_ACCEPT);

	peer->csr_state = GA_S_CSR_DEDICATED;

	return unc_peer_tx(peer, msg);
}

/* 10.1.2 GA-RC DISCOVERY REQUEST */
static int rx_rc_discovery_req(struct gan_peer *peer, struct msgb *msg,
				struct tlv_parsed *tp)
{
	struct ganc_bts *bts;

	if (TLVP_PRESENT(tp, GA_IE_MI)) {
		gsm48_mi_to_string(peer->imsi, sizeof(peer->imsi),
				   TLVP_VAL(tp, GA_IE_MI), TLVP_LEN(tp, GA_IE_MI));
		printf("\tfrom %s\n", peer->imsi);
	}
	if (TLVP_PRESENT(tp, GA_IE_GAN_RELEASE_IND))
		peer->gan_release = *TLVP_VAL(tp, GA_IE_GAN_RELEASE_IND);
	if (TLVP_PRESENT(tp, GA_IE_GAN_CM) && TLVP_LEN(tp, GA_IE_GAN_CM) >=2)
		memcpy(peer->gan_classmark, TLVP_VAL(tp, GA_IE_GAN_CM), 2);

	bts = select_bts(peer);
	osmo_timer_schedule(&peer->keepalive_timer,
			    bts->net->timer[TU3906]*2, 0);

	return tx_unc_disco_acc(peer, bts->segw_host, bts->ganc_host);
}

/* 10.1.5 GA-RC REGISTER REQUEST */
static int rx_rc_register_req(struct gan_peer *peer, struct msgb *msg,
			      struct tlv_parsed *tp)
{
	if (TLVP_PRESENT(tp, GA_IE_MI)) {
		gsm48_mi_to_string(peer->imsi, sizeof(peer->imsi),
				   TLVP_VAL(tp, GA_IE_MI), TLVP_LEN(tp, GA_IE_MI));
		printf("\tfrom %s\n", peer->imsi);
	}
	if (TLVP_PRESENT(tp, GA_IE_GAN_RELEASE_IND))
		peer->gan_release = *TLVP_VAL(tp, GA_IE_GAN_RELEASE_IND);
	if (TLVP_PRESENT(tp, GA_IE_GAN_CM) && TLVP_LEN(tp, GA_IE_GAN_CM) >=2)
		memcpy(peer->gan_classmark, TLVP_VAL(tp, GA_IE_GAN_CM), 2);

	peer->bts = select_bts(peer);
	osmo_timer_schedule(&peer->keepalive_timer,
			    peer->bts->net->timer[TU3906]*2, 0);

	return tx_unc_reg_acc(peer);
}

/* 10.1.12 GA CSR REQUEST */
static int rx_csr_request(struct gan_peer *peer, struct msgb *msg,
			  struct tlv_parsed *tp)
{
	return tx_csr_request_acc(peer);
}

/* 10.1.14 GA RC KEEP ALIVE */
static int rx_rc_keepalive(struct gan_peer *peer, struct msgb *msg,
			   struct tlv_parsed *tp)
{
	struct ganc_net *net = peer->bts->net;

	/* re-schedule the timer at twice the TU3906 value */
	osmo_timer_schedule(&peer->keepalive_timer, net->timer[TU3906]*2, 0);

	return 0;
}

/* 10.1.37 GA-CSR CLEAR REQUEST */
static int rx_csr_clear_req(struct gan_peer *peer, struct msgb *msg,
			    struct tlv_parsed *tp)
{
	/* FIXME: request core network to release all dedicated resources */
	return 0;
}

/* 10.1.20 GA-CSR RELEASE COMPLETE */
static int rx_csr_rel_compl(struct gan_peer *peer, struct msgb *msg,
			    struct tlv_parsed *tp)
{
	peer->csr_state = GA_S_CSR_IDLE;

	return 0;
}

/* 10.1.9 GA-RC DEREGISTER */
static int rx_rc_deregister(struct gan_peer *peer, struct msgb *msg,
			    struct tlv_parsed *tp)
{
	/* Release all resources, MS will TCP disconnect */

	/* not all MS really close the TPC connection, we have to
	 * release the TCP connection locally by release_timer! */
	return 0;
}

/* 10.1.23 GA-CSR UL DIRECT XFER */
static int rx_csr_ul_direct_xfer(struct gan_peer *peer, struct msgb *msg,
				 struct tlv_parsed *tp)
{
	uint8_t sapi = 0;

	if (TLVP_PRESENT(tp, GA_IE_SAPI_ID))
		sapi = *TLVP_VAL(tp, GA_IE_SAPI_ID) & 0x7;

	if (TLVP_PRESENT(tp, GA_IE_L3_MSG))
		printf("\tL3(%u): %s\n", sapi,
		       osmo_hexdump(TLVP_VAL(tp, GA_IE_L3_MSG),
				    TLVP_LEN(tp, GA_IE_L3_MSG)));
	return 0;
}

/* 10.1.27 GA-CSR CLASSMARK CHANGE */
static int rx_csr_cm_chg(struct gan_peer *peer, struct msgb *msg,
			 struct tlv_parsed *tp)
{
	if (TLVP_PRESENT(tp, GA_IE_MS_CLASSMARK2) &&
	    TLVP_LEN(tp, GA_IE_MS_CLASSMARK2) == 3)
		memcpy(peer->cm2, TLVP_VAL(tp, GA_IE_MS_CLASSMARK2), 3);

	if (TLVP_PRESENT(tp, GA_IE_MS_CLASSMARK3)) {
		peer->cm3.len = TLVP_LEN(tp, GA_IE_MS_CLASSMARK3);
		peer->cm3.val = talloc_memdup(peer,
					TLVP_VAL(tp, GA_IE_MS_CLASSMARK3),
					peer->cm3.len);
	}
	return 0;
}

static int rx_unc_rc_csr(struct gan_peer *peer, struct msgb *msg,
			 struct gan_rc_csr_hdr *gh, struct tlv_parsed *tp)
{
	switch (gh->msg_type) {
	case GA_MT_RC_DISCOVERY_REQUEST:
		return rx_rc_discovery_req(peer, msg, tp);
	case GA_MT_RC_REGISTER_REQUEST:
		return rx_rc_register_req(peer, msg, tp);
	case GA_MT_CSR_REQUEST:
		return rx_csr_request(peer, msg, tp);
	case GA_MT_CSR_CLEAR_REQ:
		return rx_csr_clear_req(peer, msg, tp);
	case GA_MT_CSR_RELEASE_COMPL:
		return rx_csr_rel_compl(peer, msg, tp);
	case GA_MT_RC_DEREGISTER:
		return rx_rc_deregister(peer, msg, tp);
	case GA_MT_CSR_UL_DIRECT_XFER:
		return rx_csr_ul_direct_xfer(peer, msg, tp);
	case GA_MT_CSR_CM_CHANGE:
		return rx_csr_cm_chg(peer, msg, tp);
	case GA_MT_RC_KEEPALIVE:
		return rx_rc_keepalive(peer, msg, tp);
		break;
	default:
		printf("\tunhandled!\n");
		break;
	}

	return 0;
}

static int rx_unc_msg(struct gan_peer *peer, struct msgb *msg)
{
	struct gan_rc_csr_hdr *gh = (struct gan_rc_csr_hdr *) msg->l2h;
	struct tlv_parsed tp;
	int len = ntohs(gh->len);
	int rc;

	printf("-> (%u) %s\n", gh->pdisc, get_value_string(gan_msgt_vals, gh->msg_type));

	if (len > 2) {
		rc = tlv_parse(&tp, &tlv_att_def, gh->data, len - 2, 0, 0);
		if (rc < 0)
			fprintf(stderr, "error %d during tlv_parse\n", rc);
	} else
		memset(&tp, 0, sizeof(tp));

	switch (gh->pdisc) {
	case GA_PDISC_RC:
	case GA_PDISC_CSR:
		return rx_unc_rc_csr(peer, msg, gh, &tp);
	case GA_PDISC_PSR:
	default:
		break;
	}

	return 0;
}

static int unc_read_cb(struct osmo_conn *conn)
{
	struct msgb *msg;
	int rc, len;

	msg = msgb_alloc_headroom(1024 + 128, 128, "UNC Read");
	if (!msg)
		return -ENOMEM;

	rc = read(conn->queue.bfd.fd, msg->data, 2);
	if (rc <= 0) {
		msgb_free(msg);
		gan_peer_destroy(conn->priv);
		osmo_conn_close(conn);
		return rc;
	} else if (rc != 2) {
		msgb_free(msg);
		fprintf(stderr, "unable to read 2 length bytes\n");
		return -EIO;
	}
	msg->l2h = msg->data;
	msgb_put(msg, rc);

	len = ntohs(*(uint16_t *)msg->data);

	rc = read(conn->queue.bfd.fd, msg->data+2, len);
	if (rc < 0) {
		msgb_free(msg);
		osmo_conn_close(conn);
		return rc;
	} else if (rc != len) {
		msgb_free(msg);
		fprintf(stderr, "unable to read %u bytes following len\n", len);
		return -EIO;
	}

	msgb_put(msg, rc);

	return rx_unc_msg(conn->priv, msg);
	/* FIXME: we have to free the msgb!! */
}

static void peer_keepalive_cb(void *_peer)
{
	struct gan_peer *peer = _peer;

	printf("=== Timeout for Peer %s, destroying\n", peer->imsi);

	gan_peer_destroy(peer);
}

static void unc_accept_cb(struct osmo_conn *conn)
{
	struct gan_peer *peer = talloc_zero(conn, struct gan_peer);
	printf("accepted connection\n");

	peer->bts = NULL;
	peer->conn = conn;
	conn->priv = peer;

	peer->sccp_con = NULL;

	/* start keepalive timer at hard-coded 5*30 seconds until we later
	 * change it to a TU3906 derived value */
	peer->keepalive_timer.cb = peer_keepalive_cb;
	peer->keepalive_timer.data = peer;
	osmo_timer_schedule(&peer->keepalive_timer, 5*30, 0);

	/* TODO: remove from list when closed */
	llist_add_tail(&peer->entry, &g_ganc_bts->net->peers);
}


int ganc_server_start(const char *host, uint16_t port)
{
	struct osmo_link *link;
	int i;

	for (i = 0; i < ARRAY_SIZE(tlv_att_def.def); i++)
		tlv_att_def.def[i].type = TLV_TYPE_TLV;

	link = osmo_link_create(NULL, host, port, unc_read_cb, 10);
	if (!link)
		return -ENOMEM;

	osmo_link_listen(link, unc_accept_cb);

	return 0;
}