iu_client: introduce ranap_iu_tx_release_free()

ranap_iu_tx_release_free is a fire and forget function to release
gracefully if possible. It first sends a Iu Release Command. After
a certain timeout the connection will be released.

Change-Id: I349e2c61ba0131e233b7ab927dfced0bd461dd8f

3 files changed, 28 insertions, 0 deletions

diff --git a/TODO-RELEASE b/TODO-RELEASE
index 41d04bc..bcbf5de 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -8,3 +8,4 @@
 # If any interfaces have been removed or changed since the last public release: c:r:0.
 #library	what		description / commit summary line
 libranap    iu_client.h struct ranap_ue_conn_ctx: add field notification
+libranap    iu_client.h struct ranap_ue_conn_ctx: add field release_timeout
diff --git a/include/osmocom/ranap/iu_client.h b/include/osmocom/ranap/iu_client.h
index b388529..a93fff3 100644
--- a/include/osmocom/ranap/iu_client.h
+++ b/include/osmocom/ranap/iu_client.h
@@ -31,6 +31,8 @@ struct ranap_ue_conn_ctx {
 	struct gprs_ra_id ra_id;
 	enum ranap_nsap_addr_enc rab_assign_addr_enc;
 	bool notification; /* send notification to the upstream user */
+	/* Will be set when the Iu Release Command has been sent */
+	struct osmo_timer_list release_timeout;
 };
 
 enum ranap_iu_event_type {
@@ -71,6 +73,13 @@ int ranap_iu_tx_sec_mode_cmd(struct ranap_ue_conn_ctx *uectx, struct osmo_auth_v
 int ranap_iu_tx_common_id(struct ranap_ue_conn_ctx *ue_ctx, const char *imsi);
 int ranap_iu_tx_release(struct ranap_ue_conn_ctx *ctx, const struct RANAP_Cause *cause);
 
+/* transmit a Iu Release Command and free the ctx afterwards.
+ * If a Release Complete is not received within timeout s,
+ * release the SCCP connection. */
+void ranap_iu_tx_release_free(struct ranap_ue_conn_ctx *ctx,
+			      const struct RANAP_Cause *cause,
+			      int timeout);
+
 /* freeing the UE will release all resources
  * This will close the SCCP connection connected to the UE */
 void ranap_iu_free_ue(struct ranap_ue_conn_ctx *ue_ctx);
diff --git a/src/iu_client.c b/src/iu_client.c
index 38c8a1d..e4eb83e 100644
--- a/src/iu_client.c
+++ b/src/iu_client.c
@@ -129,6 +129,9 @@ static struct ranap_ue_conn_ctx *ue_conn_ctx_alloc(struct ranap_iu_rnc *rnc, uin
 	ctx->rnc = rnc;
 	ctx->conn_id = conn_id;
 	ctx->notification = true;
+	osmo_timer_setup(&ctx->release_timeout,
+			 (void *)(void *) ranap_iu_free_ue,
+			 ctx);
 	llist_add(&ctx->list, &ue_conn_ctx_list);
 
 	return ctx;
@@ -150,6 +153,7 @@ void ranap_iu_free_ue(struct ranap_ue_conn_ctx *ue_ctx)
 	if (!ue_ctx)
 		return;
 
+	osmo_timer_del(&ue_ctx->release_timeout);
 	osmo_sccp_tx_disconn(g_scu, ue_ctx->conn_id, NULL, 0);
 	llist_del(&ue_ctx->list);
 	talloc_free(ue_ctx);
@@ -491,6 +495,20 @@ int ranap_iu_tx_release(struct ranap_ue_conn_ctx *ctx, const struct RANAP_Cause
 	return osmo_sccp_user_sap_down(g_scu, &prim->oph);
 }
 
+void ranap_iu_tx_release_free(struct ranap_ue_conn_ctx *ctx,
+			     const struct RANAP_Cause *cause,
+			     int timeout)
+{
+	ctx->notification = false;
+	int ret = ranap_iu_tx_release(ctx, cause);
+	if (ret) {
+		ranap_iu_free_ue(ctx);
+		return;
+	}
+
+	osmo_timer_schedule(&ctx->release_timeout, timeout, 0);
+}
+
 static int ranap_handle_co_iu_rel_req(struct ranap_ue_conn_ctx *ctx, RANAP_Iu_ReleaseRequestIEs_t *ies)
 {
 	LOGPIU(LOGL_INFO, "Received Iu Release Request, Sending Release Command\n");