nat: Introduce the concept of a paging group and use it

A paging group is a list of LACs, different BSCs can point
to a paging group and use it for the LAC lookup.

2 files changed, 38 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index e6f555cbf..85c9eaa48 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -38,6 +38,8 @@
 #define DIR_BSC 1
 #define DIR_MSC 2
 
+#define PAGIN_GROUP_UNASSIGNED -1
+
 struct sccp_source_reference;
 struct sccp_connections;
 struct bsc_nat_parsed;
@@ -134,6 +136,7 @@ struct bsc_config {
 	char *acc_lst_name;
 
 	int forbid_paging;
+	int paging_group;
 
 	/* audio handling */
 	int max_endpoints;
@@ -151,6 +154,14 @@ struct bsc_lac_entry {
 	uint16_t lac;
 };
 
+struct bsc_nat_paging_group {
+	struct llist_head entry;
+
+	/* list of lac entries */
+	struct llist_head lists;
+	int nr;
+};
+
 /**
  * BSCs point of view of endpoints
  */
@@ -225,6 +236,9 @@ struct bsc_nat {
 	/* access lists */
 	struct llist_head access_lists;
 
+	/* paging groups */
+	struct llist_head paging_groups;
+
 	/* known BSC's */
 	struct llist_head bsc_configs;
 	int num_bsc;
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index 0a565a9b7..512656a6b 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -90,6 +90,7 @@ struct bsc_nat *bsc_nat_alloc(void)
 
 	INIT_LLIST_HEAD(&nat->sccp_connections);
 	INIT_LLIST_HEAD(&nat->bsc_connections);
+	INIT_LLIST_HEAD(&nat->paging_groups);
 	INIT_LLIST_HEAD(&nat->bsc_configs);
 	INIT_LLIST_HEAD(&nat->access_lists);
 	INIT_LLIST_HEAD(&nat->dests);
@@ -137,6 +138,7 @@ struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token)
 	conf->nr = nat->num_bsc;
 	conf->nat = nat;
 	conf->max_endpoints = 32;
+	conf->paging_group = PAGIN_GROUP_UNASSIGNED;
 
 	INIT_LLIST_HEAD(&conf->lac_list);
 
@@ -187,14 +189,36 @@ void bsc_config_del_lac(struct bsc_config *cfg, int _lac)
 		}
 }
 
+static struct bsc_nat_paging_group *bsc_nat_paging_group_num(
+					struct bsc_nat *nat, int group)
+{
+	struct bsc_nat_paging_group *pgroup;
+
+	llist_for_each_entry(pgroup, &nat->paging_groups, entry)
+		if (pgroup->nr == group)
+			return pgroup;
+
+	return NULL;
+}
+
 int bsc_config_handles_lac(struct bsc_config *cfg, int lac_nr)
 {
+	struct bsc_nat_paging_group *pgroup;
 	struct bsc_lac_entry *entry;
 
 	llist_for_each_entry(entry, &cfg->lac_list, entry)
 		if (entry->lac == lac_nr)
 			return 1;
 
+	/* now lookup the paging group */
+	pgroup = bsc_nat_paging_group_num(cfg->nat, cfg->paging_group);
+	if (!pgroup)
+		return 0;
+
+	llist_for_each_entry(entry, &pgroup->lists, entry)
+		if (entry->lac == lac_nr)
+			return 1;
+
 	return 0;
 }