aboutsummaryrefslogtreecommitdiffstats
path: root/openbsc/src/gsm_subscriber_base.c
blob: 48374eae5d49cc04b3d2897e1b1ecde8c5fd845a (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
/* The concept of a subscriber as seen by the BSC */

/* (C) 2008 by Harald Welte <laforge@gnumonks.org>
 * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.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 <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include <openbsc/talloc.h>
#include <openbsc/gsm_subscriber.h>
#include <openbsc/paging.h>
#include <openbsc/debug.h>
#include <openbsc/paging.h>

LLIST_HEAD(active_subscribers);
void *tall_subscr_ctx;
void *tall_sub_req_ctx;

/* for the gsm_subscriber.c */
struct llist_head *subscr_bsc_active_subscriber(void)
{
	return &active_subscribers;
}

/*
 * Struct for pending channel requests. This is managed in the
 * llist_head requests of each subscriber. The reference counting
 * should work in such a way that a subscriber with a pending request
 * remains in memory.
 */
struct subscr_request {
	struct llist_head entry;

	/* back reference */
	struct gsm_subscriber *subscr;

	/* the requested channel type */
	int channel_type;

	/* the callback data */
	gsm_cbfn *cbfn;
	void *param;
};

/*
 * We got the channel assigned and can now hand this channel
 * over to one of our callbacks.
 */
static int subscr_paging_cb(unsigned int hooknum, unsigned int event,
			     struct msgb *msg, void *data, void *param)
{
	struct subscr_request *request;
	struct gsm_subscriber *subscr = (struct gsm_subscriber *)param;

	/* There is no request anymore... */
	if (llist_empty(&subscr->requests))
		return -1;

	/*
	 * FIXME: What to do with paging requests coming during
	 * this callback? We must be sure to not start paging when
	 * we have an active connection to a subscriber and to make
	 * the subscr_put_channel work as required...
	 */
	request = (struct subscr_request *)subscr->requests.next;
	llist_del(&request->entry);
	subscr->in_callback = 1;
	request->cbfn(hooknum, event, msg, data, request->param);
	subscr->in_callback = 0;

	talloc_free(request);
	return 0;
}

static void subscr_send_paging_request(struct gsm_subscriber *subscr)
{
	struct subscr_request *request;
	int rc;

	assert(!llist_empty(&subscr->requests));

	request = (struct subscr_request *)subscr->requests.next;
	rc = paging_request(subscr->net, subscr, request->channel_type,
			    subscr_paging_cb, subscr);

	/* paging failed, quit now */
	if (rc <= 0) {
		subscr_paging_cb(GSM_HOOK_RR_PAGING, GSM_PAGING_EXPIRED,
				 NULL, NULL, request->param);
	}
}

struct gsm_subscriber *subscr_alloc(void)
{
	struct gsm_subscriber *s;

	s = talloc_zero(tall_subscr_ctx, struct gsm_subscriber);
	if (!s)
		return NULL;

	llist_add_tail(&s->entry, &active_subscribers);
	s->use_count = 1;
	s->tmsi = GSM_RESERVED_TMSI;

	INIT_LLIST_HEAD(&s->requests);

	return s;
}

static void subscr_free(struct gsm_subscriber *subscr)
{
	llist_del(&subscr->entry);
	talloc_free(subscr);
}

struct gsm_subscriber *subscr_get(struct gsm_subscriber *subscr)
{
	subscr->use_count++;
	DEBUGP(DCC, "subscr %s usage increases usage to: %d\n",
			subscr->extension, subscr->use_count);
	return subscr;
}

struct gsm_subscriber *subscr_put(struct gsm_subscriber *subscr)
{
	subscr->use_count--;
	DEBUGP(DCC, "subscr %s usage decreased usage to: %d\n",
			subscr->extension, subscr->use_count);
	if (subscr->use_count <= 0)
		subscr_free(subscr);
	return NULL;
}

void subscr_get_channel(struct gsm_subscriber *subscr,
			int type, gsm_cbfn *cbfn, void *param)
{
	struct subscr_request *request;

	request = talloc(tall_sub_req_ctx, struct subscr_request);
	if (!request) {
		if (cbfn)
			cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_OOM,
				NULL, NULL, param);
		return;
	}

	memset(request, 0, sizeof(*request));
	request->subscr = subscr;
	request->channel_type = type;
	request->cbfn = cbfn;
	request->param = param;

	/*
	 * FIXME: We might be able to assign more than one
	 * channel, e.g. voice and SMS submit at the same
	 * time.
	 */
	if (!subscr->in_callback && llist_empty(&subscr->requests)) {
		/* add to the list, send a request */
		llist_add_tail(&request->entry, &subscr->requests);
		subscr_send_paging_request(subscr);
	} else {
		/* this will be picked up later, from subscr_put_channel */
		llist_add_tail(&request->entry, &subscr->requests);
	}
}

void subscr_put_channel(struct gsm_lchan *lchan)
{
	/*
	 * FIXME: Continue with other requests now... by checking
	 * the gsm_subscriber inside the gsm_lchan. Drop the ref count
	 * of the lchan after having asked the next requestee to handle
	 * the channel.
	 */
	/*
	 * FIXME: is the lchan is of a different type we could still
	 * issue an immediate assignment for another channel and then
	 * close this one.
	 */
	/*
	 * Currently we will drop the last ref of the lchan which
	 * will result in a channel release on RSL and we will start
	 * the paging. This should work most of the time as the MS
	 * will listen to the paging requests before we timeout
	 */

	put_lchan(lchan);

	if (lchan->subscr && !llist_empty(&lchan->subscr->requests))
		subscr_send_paging_request(lchan->subscr);
}