gsup: add OSMO_GSUP_SUPPORTED_RAT_TYPES_IE and OSMO_GSUP_CURRENT_RAT_TYPE_IE

OSMO_GSUP_SUPPORTED_RAT_TYPES_IE corresponds to the Supported RAT Types
Indicator from 3GPP TS 29.002. See 8.1.2 MAP_UPDATE_LOCATION service,
which indicates the capabilities of the MSC/VLR to the HLR.

So far, have room for eight RAT types in the gsup_msg. That is an arbitrary
random choice without any rationale.

OSMO_GSUP_CURRENT_RAT_TYPE_IE is useful to communicate the currently
used RAN / RAT type of the current subscriber during Location Updating Request.

Change-Id: I93850710ab55a605bf61b95063a69682a2899bb1

3 files changed, 49 insertions, 7 deletions

diff --git a/include/osmocom/gsm/gsup.h b/include/osmocom/gsm/gsup.h
index be856620..49ddb742 100644
--- a/include/osmocom/gsm/gsup.h
+++ b/include/osmocom/gsm/gsup.h
@@ -45,6 +45,7 @@
 #include <osmocom/gsm/protocol/gsm_03_40.h>
 #include <osmocom/gsm/protocol/gsm_04_08_gprs.h>
 #include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/gsm_utils.h>
 #include <osmocom/crypt/auth.h>
 
 #define OSMO_GSUP_PORT 4222
@@ -86,6 +87,8 @@ enum osmo_gsup_iei {
 	OSMO_GSUP_AUTS_IE			= 0x26,
 	OSMO_GSUP_RES_IE			= 0x27,
 	OSMO_GSUP_CN_DOMAIN_IE			= 0x28,
+	OSMO_GSUP_SUPPORTED_RAT_TYPES_IE	= 0x29, /* supported RAT types */
+	OSMO_GSUP_CURRENT_RAT_TYPE_IE		= 0x2a, /* currently used RAT type */
 
 	OSMO_GSUP_SESSION_ID_IE			= 0x30,
 	OSMO_GSUP_SESSION_STATE_IE		= 0x31,
@@ -373,6 +376,10 @@ struct osmo_gsup_message {
 
 	/*! Session Management cause as of 3GPP TS 24.008 10.5.6.6 / Table 10.5.157. */
 	enum gsm48_gsm_cause		cause_sm;
+
+	enum osmo_rat_type		current_rat_type;
+	enum osmo_rat_type		supported_rat_types[8]; /*!< arbitrary choice */
+	size_t				supported_rat_types_len;
 };
 
 int osmo_gsup_decode(const uint8_t *data, size_t data_len,
diff --git a/src/gsm/gsup.c b/src/gsm/gsup.c
index 2e6690ee..2f9d85d8 100644
--- a/src/gsm/gsup.c
+++ b/src/gsm/gsup.c
@@ -297,6 +297,7 @@ int osmo_gsup_decode(const uint8_t *const_data, size_t data_len,
 		     struct osmo_gsup_message *gsup_msg)
 {
 	int rc;
+	int i;
 	uint8_t tag;
 	/* the shift/match functions expect non-const pointers, but we'll
 	 * either copy the data or cast pointers back to const before returning
@@ -459,6 +460,21 @@ int osmo_gsup_decode(const uint8_t *const_data, size_t data_len,
 			gsup_msg->cn_domain = *value;
 			break;
 
+		case OSMO_GSUP_SUPPORTED_RAT_TYPES_IE:
+			if (value_len > ARRAY_SIZE(gsup_msg->supported_rat_types)) {
+				LOGP(DLGSUP, LOGL_ERROR, "nr of supported RAT types %zu > %zu\n",
+					value_len, ARRAY_SIZE(gsup_msg->supported_rat_types));
+				return -GMM_CAUSE_COND_IE_ERR;
+			}
+			for (i = 0; i < value_len; i++)
+				gsup_msg->supported_rat_types[i] = value[i];
+			gsup_msg->supported_rat_types_len = value_len;
+			break;
+
+		case OSMO_GSUP_CURRENT_RAT_TYPE_IE:
+			gsup_msg->current_rat_type = *value;
+			break;
+
 		case OSMO_GSUP_CHARG_CHAR_IE:
 			gsup_msg->pdp_charg_enc = value;
 			gsup_msg->pdp_charg_enc_len = value_len;
@@ -856,6 +872,25 @@ int osmo_gsup_encode(struct msgb *msg, const struct osmo_gsup_message *gsup_msg)
 	if ((u8 = gsup_msg->cause_sm))
 		msgb_tlv_put(msg, OSMO_GSUP_CAUSE_SM_IE, sizeof(u8), &u8);
 
+	if (gsup_msg->supported_rat_types_len) {
+		int i;
+		uint8_t *len = msgb_tl_put(msg, OSMO_GSUP_SUPPORTED_RAT_TYPES_IE);
+		*len = gsup_msg->supported_rat_types_len;
+		for (i = 0; i < gsup_msg->supported_rat_types_len; i++) {
+			if (!gsup_msg->supported_rat_types[i] ||
+			    gsup_msg->supported_rat_types[i] >= OSMO_RAT_COUNT) {
+				LOGP(DLGSUP, LOGL_ERROR, "Failed to encode RAT type %s (nr %d)\n",
+				     osmo_rat_type_name(gsup_msg->supported_rat_types[i]), i);
+				return -EINVAL;
+			}
+			msgb_v_put(msg, gsup_msg->supported_rat_types[i]);
+		}
+	}
+	if (gsup_msg->current_rat_type != OSMO_RAT_UNKNOWN) {
+		u8 = gsup_msg->current_rat_type;
+		msgb_tlv_put(msg, OSMO_GSUP_CURRENT_RAT_TYPE_IE, sizeof(u8), &u8);
+	}
+
 	return 0;
 }
 
diff --git a/tests/gsup/gsup_test.err b/tests/gsup/gsup_test.err
index e5fe6ee3..1da39649 100644
--- a/tests/gsup/gsup_test.err
+++ b/tests/gsup/gsup_test.err
@@ -157,27 +157,27 @@
 DLGSUP Stopping DLGSUP logging
   message 0: tested 3584 modifications, 771 parse failures
   message 1: tested 3584 modifications, 770 parse failures
-  message 2: tested 21248 modifications, 2575 parse failures
+  message 2: tested 21248 modifications, 2577 parse failures
   message 3: tested 2816 modifications, 510 parse failures
   message 4: tested 3584 modifications, 770 parse failures
-  message 5: tested 20736 modifications, 4023 parse failures
+  message 5: tested 20736 modifications, 4025 parse failures
   message 6: tested 3584 modifications, 771 parse failures
   message 7: tested 3584 modifications, 770 parse failures
   message 8: tested 2816 modifications, 510 parse failures
   message 9: tested 2816 modifications, 510 parse failures
   message 10: tested 3584 modifications, 770 parse failures
   message 11: tested 3328 modifications, 770 parse failures
-  message 12: tested 54016 modifications, 4626 parse failures
-  message 13: tested 11520 modifications, 1026 parse failures
+  message 12: tested 54016 modifications, 4628 parse failures
+  message 13: tested 11520 modifications, 1028 parse failures
   message 14: tested 5120 modifications, 1030 parse failures
-  message 15: tested 10752 modifications, 1262 parse failures
+  message 15: tested 10752 modifications, 1263 parse failures
   message 16: tested 7680 modifications, 1271 parse failures
   message 17: tested 8448 modifications, 2053 parse failures
-  message 18: tested 11264 modifications, 2307 parse failures
+  message 18: tested 11264 modifications, 2308 parse failures
   message 19: tested 5120 modifications, 1031 parse failures
   message 20: tested 4352 modifications, 1030 parse failures
   message 21: tested 3584 modifications, 771 parse failures
-  message 22: tested 5632 modifications, 771 parse failures
+  message 22: tested 5632 modifications, 772 parse failures
   message 23: tested 3584 modifications, 770 parse failures
   message 24: tested 3584 modifications, 771 parse failures
   message 25: tested 11264 modifications, 2058 parse failures