gmm: Implement rx RAU Reject

Change-Id: I0d4d8288b78cfd3140c786a52a3906eaf37ebe6b
---
M include/osmocom/gprs/gmm/gmm_ms_fsm.h
M src/gmm/gmm.c
M src/gmm/gmm_ms_fsm.c
3 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/include/osmocom/gprs/gmm/gmm_ms_fsm.h b/include/osmocom/gprs/gmm/gmm_ms_fsm.h
index 1ebc53c..772444f 100644
--- a/include/osmocom/gprs/gmm/gmm_ms_fsm.h
+++ b/include/osmocom/gprs/gmm/gmm_ms_fsm.h
@@ -51,7 +51,7 @@
 	GPRS_GMM_MS_EV_SR_REJECTED, /* (Iu only) */
 	GPRS_GMM_MS_EV_SR_ACCEPTED, /* (Iu only) */
 	GPRS_GMM_MS_EV_RAU_REQUESTED,
-	GPRS_GMM_MS_EV_RAU_REJECTED,
+	GPRS_GMM_MS_EV_RAU_REJECTED, /* data: ptr to "uint8_t cause" */
 	GPRS_GMM_MS_EV_RAU_ACCEPTED,
 	GPRS_GMM_MS_EV_LOW_LVL_FAIL,
 };
diff --git a/src/gmm/gmm.c b/src/gmm/gmm.c
index c96917b..4836d58 100644
--- a/src/gmm/gmm.c
+++ b/src/gmm/gmm.c
@@ -1137,6 +1137,49 @@
 	return -EINVAL; /* TODO: what to do on error? */
 }
 
+/* Rx GMM Routing area update reject, 9.4.17 */
+static int gprs_gmm_rx_rau_rej(struct gprs_gmm_entity *gmme, struct gsm48_hdr *gh, unsigned int len)
+{
+	uint8_t *buf = &gh->data[0];
+	struct tlv_parsed tp;
+	uint8_t cause = GMM_CAUSE_SEM_INCORR_MSG;
+	bool force_standby_indicated;
+	int rc;
+
+	if (len < sizeof(*gh) + 2) {
+		LOGGMME(gmme, LOGL_ERROR, "Rx GMM ROUTING AREA UPDATE REJECT with wrong size %u\n", len);
+		goto rejected;
+	}
+
+	cause = buf[0];
+	force_standby_indicated = (buf[1] >> 4) == 0x01;
+	buf += 2;
+
+	LOGGMME(gmme, LOGL_NOTICE, "Rx GMM ROUTING AREA UPDATE REJECT cause='%s' (%u) force_stdby=%u\n",
+		get_value_string(gsm48_gmm_cause_names, cause), cause, force_standby_indicated);
+
+	if (force_standby_indicated)
+		gprs_gmm_gmme_ready_timer_stop(gmme);
+
+	if (len > (buf - (uint8_t *)gh)) {
+		rc = gprs_gmm_tlv_parse(&tp, buf, len - (buf - (uint8_t *)gh));
+		if (rc < 0) {
+			LOGGMME(gmme, LOGL_ERROR, "Rx GMM ROUTING AREA UPDATE REJECT: failed to parse TLVs %d\n", rc);
+			goto rejected;
+		}
+
+		if (TLVP_PRES_LEN(&tp, GSM48_IE_GMM_TIMER_T3302, 1))
+			gmme->t3302 = *TLVP_VAL(&tp, GSM48_IE_GMM_TIMER_T3302);
+
+		if (TLVP_PRES_LEN(&tp, GSM48_IE_GMM_TIMER_T3346, 1))
+			gmme->t3346 = *TLVP_VAL(&tp, GSM48_IE_GMM_TIMER_T3346);
+	}
+
+rejected:
+	rc = osmo_fsm_inst_dispatch(gmme->ms_fsm.fi, GPRS_GMM_MS_EV_RAU_REJECTED, &cause);
+	return -EINVAL;
+}
+
 /* Rx GMM Identity Request, 9.2.10 */
 static int gprs_gmm_rx_id_req(struct gprs_gmm_entity *gmme, struct gsm48_hdr *gh, unsigned int len)
 {
@@ -1380,6 +1423,9 @@
 	case GSM48_MT_GMM_RA_UPD_ACK:
 		rc = gprs_gmm_rx_rau_acc(gmme, gh, len);
 		break;
+	case GSM48_MT_GMM_RA_UPD_REJ:
+		rc = gprs_gmm_rx_rau_rej(gmme, gh, len);
+		break;
 	case GSM48_MT_GMM_ID_REQ:
 		rc = gprs_gmm_rx_id_req(gmme, gh, len);
 		break;
diff --git a/src/gmm/gmm_ms_fsm.c b/src/gmm/gmm_ms_fsm.c
index e5a7002..ff26dfa 100644
--- a/src/gmm/gmm_ms_fsm.c
+++ b/src/gmm/gmm_ms_fsm.c
@@ -239,13 +239,22 @@
 {
 	struct gprs_gmm_ms_fsm_ctx *ctx = (struct gprs_gmm_ms_fsm_ctx *)fi->priv;
 	struct osmo_gprs_llc_prim *llc_prim_tx;
+	enum gsm48_gmm_cause cause;
 
 	switch (event) {
 	case GPRS_GMM_MS_EV_RAU_REJECTED:
-		// causes #13, #15, #25
-		gmm_ms_fsm_state_chg(fi, GPRS_GMM_MS_ST_REGISTERED);
-		// else
-		//mm_ms_fsm_state_chg(fi, GPRS_GMM_MS_ST_DEREGISTERED_INITIATED);
+		cause = *(uint8_t *)data;
+		/* 3GPP TS 24.008 Figure 4.1b */
+		switch (cause) {
+		case GMM_CAUSE_ROAMING_NOTALLOWED:
+		case GMM_CAUSE_NO_SUIT_CELL_IN_LA:
+		case GMM_CAUSE_NOT_AUTH_FOR_CSG:
+			gmm_ms_fsm_state_chg(fi, GPRS_GMM_MS_ST_REGISTERED);
+			break;
+		default:
+			gmm_ms_fsm_state_chg(fi, GPRS_GMM_MS_ST_DEREGISTERED);
+			break;
+		}
 		break;
 	case GPRS_GMM_MS_EV_RAU_ACCEPTED:
 		gprs_gmm_gmme_t3316_stop(ctx->gmme);
@@ -351,7 +360,6 @@
 			X(GPRS_GMM_MS_EV_RAU_ACCEPTED),
 		.out_state_mask =
 			X(GPRS_GMM_MS_ST_REGISTERED) |
-			X(GPRS_GMM_MS_ST_DEREGISTERED_INITIATED) |
 			X(GPRS_GMM_MS_ST_DEREGISTERED),
 		.name = "RAUInitidated",
 		.action = st_gmm_ms_rau_initiated,

