Start creating a paging layer...

You can request to open a channel to a MS and the paging layer
will call you once the channel is allocated. Internally the CCCH
Load Indication will be handled and retry to page a terminal.

include/openbsc/Makefile.am

@@ -1,3 +1,3 @@
 noinst_HEADERS = abis_nm.h abis_rsl.h debug.h db.h gsm_04_08.h gsm_data.h \
 		 gsm_subscriber.h linuxlist.h msgb.h select.h tlv.h gsm_04_11.h \
-		 timer.h misdn.h chan_alloc.h telnet_interface.h
+		 timer.h misdn.h chan_alloc.h telnet_interface.h paging.h

include/openbsc/paging.h

@@ -0,0 +1,61 @@
+/* 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.
+ *
+ */
+
+#ifndef PAGING_H
+#define PAGING_H
+
+#include <malloc.h>
+#include <string.h>
+
+#include "linuxlist.h"
+#include "gsm_data.h"
+#include "gsm_subscriber.h"
+
+/**
+ * A pending paging request 
+ */
+struct paging_request {
+	struct llist_head entry;
+	struct gsm_subscriber *subscr;
+	struct gsm_bts *bts;
+};
+
+/*
+ * struct for each bts we serve...
+ */
+struct paging_bts {
+	/* public callbacks */
+	void (*channel_allocated)(struct gsm_lchan *lchan);
+
+	/* list for each bts */
+	struct llist_head bts_list;
+
+	/* pending requests */
+	struct llist_head pending_requests;
+	struct gsm_bts *bts;
+};
+
+/* call once for every gsm_bts... */
+struct paging_bts* page_allocate(struct gsm_bts *bts);
+
+/* schedule paging request */
+void page_request(struct gsm_bts *bts, struct gsm_subscriber *subscr);
+
+#endif

src/Makefile.am

@@ -6,5 +6,5 @@ sbin_PROGRAMS = bsc_hack
 bsc_hack_SOURCES = bsc_hack.c misdn.c abis_rsl.c abis_nm.c gsm_04_08.c gsm_data.c \
 		gsm_subscriber.c msgb.c select.c chan_alloc.c timer.c debug.c db.c \
 		gsm_04_11.c telnet_interface.c telnet_parser.l subchan_demux.c \
-		trau_frame.c
+		trau_frame.c paging.c
 bsc_hack_LDADD = -ldl -ldbi

src/paging.c

@@ -0,0 +1,83 @@
+/* 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 <openbsc/paging.h>
+#include <openbsc/debug.h>
+
+static LLIST_HEAD(managed_bts);
+
+static int page_pending_request(struct paging_bts *bts,
+				struct gsm_subscriber *subscr) {
+	struct paging_request *req;
+
+	llist_for_each_entry(req, &bts->pending_requests, entry) {
+		if (subscr == req->subscr)
+			return 1;
+	}
+
+	return 0;	
+}
+
+struct paging_bts* page_allocate(struct gsm_bts *bts) {
+	struct paging_bts *page;
+
+	page = (struct paging_bts *)malloc(sizeof(*page));
+	memset(page, 0, sizeof(*page));
+	llist_add_tail(&page->bts_list, &managed_bts);
+
+	return page;
+}
+
+void page_request(struct gsm_bts *bts, struct gsm_subscriber *subscr) {
+	struct paging_bts *bts_entry;
+	struct paging_request *req;
+
+	req = (struct paging_request *)malloc(sizeof(*req));
+	req->subscr = subscr_get(subscr);
+	req->bts = bts;
+
+	llist_for_each_entry(bts_entry, &managed_bts, bts_list) {
+		if (bts == bts_entry->bts && !page_pending_request(bts_entry, subscr)) {
+			llist_add_tail(&req->entry, &bts_entry->pending_requests);
+			return;
+		}
+	}
+
+	DEBUGP(DPAG, "Paging request for not mnaged BTS\n");
+	free(req);
+	return;
+}