1 files changed, 262 insertions, 0 deletions
diff --git a/openbsc/src/paging.c b/openbsc/src/paging.c
new file mode 100644
index 000000000..d777d6642
--- /dev/null
+++ b/openbsc/src/paging.c
@@ -0,0 +1,262 @@
+/* Paging helper and manager.... */
+/* (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.
+ *
+ */
+
+/*
+ * Relevant specs:
+ *     12.21:
+ *       - 9.4.12 for CCCH Local Threshold
+ *
+ *     05.58:
+ *       - 8.5.2 CCCH Load indication
+ *       - 9.3.15 Paging Load
+ *
+ * Approach:
+ *       - Send paging command to subscriber
+ *       - On Channel Request we will remember the reason
+ *       - After the ACK we will request the identity
+ *	 - Then we will send assign the gsm_subscriber and
+ *	 - and call a callback
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include <openbsc/paging.h>
+#include <openbsc/debug.h>
+#include <openbsc/signal.h>
+#include <openbsc/abis_rsl.h>
+#include <openbsc/gsm_data.h>
+
+#define PAGING_TIMEOUT 1, 75000
+#define MAX_PAGING_REQUEST 750
+
+static unsigned int calculate_group(struct gsm_bts *bts, struct gsm_subscriber *subscr)
+{
+	int ccch_conf;
+	int bs_cc_chans;
+	int blocks;
+	unsigned int group;
+	
+	ccch_conf = bts->chan_desc.ccch_conf;
+	bs_cc_chans = rsl_ccch_conf_to_bs_cc_chans(ccch_conf);
+	/* code word + 2, as 2 channels equals 0x0 */
+	blocks = rsl_number_of_paging_subchannels(bts);
+	group = get_paging_group(str_to_imsi(subscr->imsi),
+					bs_cc_chans, blocks);
+	return group;
+}
+
+/*
+ * Kill one paging request update the internal list...
+ */
+static void paging_remove_request(struct gsm_bts_paging_state *paging_bts,
+				struct gsm_paging_request *to_be_deleted)
+{
+	/* Update the last_request if that is necessary */
+	if (to_be_deleted == paging_bts->last_request) {
+		paging_bts->last_request =
+			(struct gsm_paging_request *)paging_bts->last_request->entry.next;
+		if (&to_be_deleted->entry == &paging_bts->pending_requests)
+			paging_bts->last_request = NULL;
+	}
+
+	bsc_del_timer(&to_be_deleted->T3113);
+	llist_del(&to_be_deleted->entry);
+	subscr_put(to_be_deleted->subscr);
+	free(to_be_deleted);
+}
+
+static void page_ms(struct gsm_paging_request *request)
+{
+	u_int8_t mi[128];
+	unsigned long int tmsi;
+	unsigned int mi_len;
+	unsigned int page_group;
+
+	DEBUGP(DPAG, "Going to send paging commands: '%s'\n",
+		request->subscr->imsi);
+
+	page_group = calculate_group(request->bts, request->subscr);
+	tmsi = strtoul(request->subscr->tmsi, NULL, 10);
+	mi_len = generate_mid_from_tmsi(mi, tmsi);
+	rsl_paging_cmd(request->bts, page_group, mi_len, mi,
+			request->chan_type);
+}
+
+static void paging_move_to_next(struct gsm_bts_paging_state *paging_bts)
+{
+	paging_bts->last_request =
+		(struct gsm_paging_request *)paging_bts->last_request->entry.next;
+	if (&paging_bts->last_request->entry == &paging_bts->pending_requests)
+		paging_bts->last_request = NULL;
+}
+
+/*
+ * This is kicked by the periodic PAGING LOAD Indicator
+ * coming from abis_rsl.c
+ *
+ * We attempt to iterate once over the list of items but
+ * only upto available_slots.
+ */
+static void paging_handle_pending_requests(struct gsm_bts_paging_state *paging_bts)
+{
+	struct gsm_paging_request *initial_request = NULL;
+	struct gsm_paging_request *current_request = NULL;
+
+	/*
+	 * Determine if the pending_requests list is empty and
+	 * return then.
+	 */
+	if (llist_empty(&paging_bts->pending_requests)) {
+		paging_bts->last_request = NULL;
+		/* since the list is empty, no need to reschedule the timer */
+		return;
+	}
+
+	if (!paging_bts->last_request)
+		paging_bts->last_request =
+			(struct gsm_paging_request *)paging_bts->pending_requests.next;
+
+	assert(paging_bts->last_request);
+	initial_request = paging_bts->last_request;
+	current_request = initial_request;
+
+	do {
+		/* handle the paging request now */
+		page_ms(current_request);
+		paging_bts->available_slots--;
+
+		/*
+		 * move to the next item. We might wrap around
+		 * this means last_request will be NULL and we just
+		 * call paging_page_to_next again. It it guranteed
+		 * that the list is not empty.
+		 */
+		paging_move_to_next(paging_bts);
+		if (!paging_bts->last_request)
+			paging_bts->last_request =
+				(struct gsm_paging_request *)paging_bts->pending_requests.next;
+		current_request = paging_bts->last_request;
+	} while (paging_bts->available_slots > 0
+		    &&  initial_request != current_request);
+
+	bsc_schedule_timer(&paging_bts->work_timer, 1, 0);
+}
+
+static void paging_worker(void *data)
+{
+	struct gsm_bts_paging_state *paging_bts = data;
+
+	paging_handle_pending_requests(paging_bts);
+}
+
+void paging_init(struct gsm_bts *bts)
+{
+	bts->paging.bts = bts;
+	INIT_LLIST_HEAD(&bts->paging.pending_requests);
+	bts->paging.work_timer.cb = paging_worker;
+	bts->paging.work_timer.data = &bts->paging;
+
+	/* Large number, until we get a proper message */
+	bts->paging.available_slots = 100;
+}
+
+static int paging_pending_request(struct gsm_bts_paging_state *bts,
+				struct gsm_subscriber *subscr) {
+	struct gsm_paging_request *req;
+
+	llist_for_each_entry(req, &bts->pending_requests, entry) {
+		if (subscr == req->subscr)
+			return 1;
+	}
+
+	return 0;	
+}
+
+static void paging_T3113_expired(void *data)
+{
+	struct gsm_paging_request *req = (struct gsm_paging_request *)data;
+	struct paging_signal_data sig_data;
+
+	DEBUGP(DPAG, "T3113 expired for request %p (%s)\n",
+		req, req->subscr->imsi);
+	
+	sig_data.subscr = req->subscr,
+	sig_data.bts	= req->bts,
+	sig_data.lchan	= NULL,
+
+	dispatch_signal(SS_PAGING, S_PAGING_COMPLETED, &sig_data);
+	if (req->cbfn)
+		req->cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_EXPIRED, NULL, NULL,
+			  req->cbfn_param);
+	paging_remove_request(&req->bts->paging, req);
+}
+
+void paging_request(struct gsm_bts *bts, struct gsm_subscriber *subscr,
+		    int type, gsm_cbfn *cbfn, void *data)
+{
+	struct gsm_bts_paging_state *bts_entry = &bts->paging;
+	struct gsm_paging_request *req;
+
+	if (paging_pending_request(bts_entry, subscr)) {
+		DEBUGP(DPAG, "Paging request already pending\n");
+		return;
+	}
+
+	req = (struct gsm_paging_request *)malloc(sizeof(*req));
+	memset(req, 0, sizeof(*req));
+	req->subscr = subscr_get(subscr);
+	req->bts = bts;
+	req->chan_type = type;
+	req->cbfn = cbfn;
+	req->cbfn_param = data;
+	req->T3113.cb = paging_T3113_expired;
+	req->T3113.data = req;
+	bsc_schedule_timer(&req->T3113, T3113_VALUE);
+	llist_add_tail(&req->entry, &bts_entry->pending_requests);
+
+	if (!bsc_timer_pending(&bts_entry->work_timer))
+		bsc_schedule_timer(&bts_entry->work_timer, 1, 0);
+}
+
+/* we consciously ignore the type of the request here */
+void paging_request_stop(struct gsm_bts *bts, struct gsm_subscriber *subscr,
+			 struct gsm_lchan *lchan)
+{
+	struct gsm_bts_paging_state *bts_entry = &bts->paging;
+	struct gsm_paging_request *req, *req2;
+
+	llist_for_each_entry_safe(req, req2, &bts_entry->pending_requests,
+				 entry) {
+		if (req->subscr == subscr) {
+			if (req->cbfn)
+				req->cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_SUCCEEDED,
+					  NULL, lchan, req->cbfn_param);
+			paging_remove_request(&bts->paging, req);
+			break;
+		}
+	}
+}
+
+void paging_update_buffer_space(struct gsm_bts *bts, u_int16_t free_slots)
+{
+	bts->paging.available_slots = free_slots;
+}