[PATCH 3/3] [channel] Handle and dispatch paging requests in gsm_subscriber

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Holger Freyther zecke at selfish.org
Sat Jun 6 12:51:01 UTC 2009


From d1e5ef15114ee6071597d4338500c553d9959c87 Mon Sep 17 00:00:00 2001
From: Holger Freyther <ich at tamarin.(none)>
Date: Sat, 18 Apr 2009 13:48:55 +0200
Subject: [PATCH 3/3] [channel] Handle and dispatch paging requests in 
gsm_subscriber

Implement subscr_get_channel to a degree that a pending SMS
Submit and a phone call should work.
---
 include/openbsc/gsm_data.h       |    1 +
 include/openbsc/gsm_subscriber.h |    1 +
 src/gsm_subscriber.c             |  113 ++++++++++++++++++++++++++++++++++++-
 3 files changed, 111 insertions(+), 4 deletions(-)

diff --git a/include/openbsc/gsm_data.h b/include/openbsc/gsm_data.h
index 297d505..9a13b4b 100644
--- a/include/openbsc/gsm_data.h
+++ b/include/openbsc/gsm_data.h
@@ -26,6 +26,7 @@ enum gsm_paging_event {
 	GSM_PAGING_SUCCEEDED,
 	GSM_PAGING_EXPIRED,
 	GSM_PAGING_VLR_UNKNOWN,
+	GSM_PAGING_OOM,
 };
 
 struct msgb;
diff --git a/include/openbsc/gsm_subscriber.h 
b/include/openbsc/gsm_subscriber.h
index abe1fd7..d5c2a90 100644
--- a/include/openbsc/gsm_subscriber.h
+++ b/include/openbsc/gsm_subscriber.h
@@ -25,6 +25,7 @@ struct gsm_subscriber {
 	struct llist_head entry;
 
 	/* pending requests */
+	int in_callback;
 	struct llist_head requests;
 };
 
diff --git a/src/gsm_subscriber.c b/src/gsm_subscriber.c
index d9e7116..200ac8f 100644
--- a/src/gsm_subscriber.c
+++ b/src/gsm_subscriber.c
@@ -25,16 +25,78 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <assert.h>
 
 #include <openbsc/gsm_subscriber.h>
 #include <openbsc/paging.h>
 #include <openbsc/debug.h>
+#include <openbsc/paging.h>
 #include <openbsc/db.h>
 
-
 LLIST_HEAD(active_subscribers);
 struct gsm_network *gsmnet = NULL;
 
+/*
+ * 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 bts we have decided to use */
+	struct gsm_bts *bts;
+
+	/* the callback data */
+	gsm_cbfn *cbfn;
+	void *data;
+};
+
+/*
+ * 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 *)data;
+
+	assert(!llist_empty(&subscr->requests));
+
+	/*
+	 * 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, request->data, param);
+	subscr->in_callback = 0;
+
+	free(request);
+	return 0;
+}
+
+static void subscr_send_paging_request(struct gsm_subscriber *subscr)
+{
+	struct subscr_request *request;
+	assert(!llist_empty(&subscr->requests));
+
+	request = (struct subscr_request *)subscr->requests.next;
+	paging_request(request->bts, subscr, request->channel_type,
+		       subscr_paging_cb, subscr);
+}
+
 struct gsm_subscriber *subscr_alloc(void)
 {
 	struct gsm_subscriber *s;
@@ -139,8 +201,10 @@ void subscr_get_channel(struct gsm_subscriber *subscr,
 			struct gsm_bts *default_bts, int type,
 			gsm_cbfn *cbfn, void *data)
 {
-	/* FIXME: Find the right BTS... */
+	struct subscr_request *request;
 	struct gsm_bts *bts;
+
+	/* FIXME: Find the right BTS... */
 	if (default_bts)
 		bts = default_bts;
 	else
@@ -149,8 +213,34 @@ void subscr_get_channel(struct gsm_subscriber *subscr,
 	if (!bts)
 		goto error;
 
-	paging_request(bts, subscr, type, cbfn, data);
-	return;
+	request = (struct subscr_request *)malloc(sizeof(*request));
+	if (!request) {
+		if (cbfn)
+			cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_OOM,
+				NULL, NULL, data);
+		return;
+	}
+
+	memset(request, 0, sizeof(*request));
+	request->bts = bts;
+	request->subscr = subscr;
+	request->channel_type = type;
+	request->cbfn = cbfn;
+	request->data = data;
+
+	/*
+	 * 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 */
+		llist_add_tail(&request->entry, &subscr->requests);
+	}
 
 error:
 	if (!cbfn)
@@ -166,7 +256,22 @@ void subscr_put_channel(struct gsm_lchan *lchan)
 	 * 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);
 }
 
 void subscr_init(struct gsm_network *net)
-- 
1.6.3.1






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