gsup: Introduce OSMO_GSUP_NUM_VECTORS_REQ_IE

This is a bit of a hack, as we want to maintain binary compatibility
without breaking existing users of libosmocore.  To do so, we use the
'num_auth_vectors' field in two ways now:

* In the existing use case as part of SEND_AUTH_INFO_RESPONSE, it
  indicates the number of vectors stored in the 'auth_vectors' field

* In the new use case as part of SEND_AUTH_INFO_REQUEST, it indicates
  the number of vectors actually requested by the MSC/SGSN/MME.

Change-Id: Iaecc47280f8ce54f3e3a888c1cfc160735483d0f

5 files changed, 33 insertions, 4 deletions

diff --git a/include/osmocom/gsm/gsup.h b/include/osmocom/gsm/gsup.h
index 285bc0c6..56d7a309 100644
--- a/include/osmocom/gsm/gsup.h
+++ b/include/osmocom/gsm/gsup.h
@@ -107,6 +107,7 @@ enum osmo_gsup_iei {
 
 	OSMO_GSUP_IMEI_IE			= 0x50,
 	OSMO_GSUP_IMEI_RESULT_IE		= 0x51,
+	OSMO_GSUP_NUM_VECTORS_REQ_IE		= 0x52,
 
 	/* Inter-MSC handover related */
 	OSMO_GSUP_SOURCE_NAME_IE		= 0x60,
diff --git a/src/gsm/gsup.c b/src/gsm/gsup.c
index ad7a2a42..ef33ed08 100644
--- a/src/gsm/gsup.c
+++ b/src/gsm/gsup.c
@@ -569,6 +569,11 @@ int osmo_gsup_decode(const uint8_t *const_data, size_t data_len,
 			gsup_msg->cause_sm = value[0];
 			break;
 
+		case OSMO_GSUP_NUM_VECTORS_REQ_IE:
+			if (gsup_msg->message_type == OSMO_GSUP_MSGT_SEND_AUTH_INFO_REQUEST)
+				gsup_msg->num_auth_vectors = value[0];
+			break;
+
 		default:
 			LOGP(DLGSUP, LOGL_NOTICE,
 			     "GSUP IE type %d unknown\n", iei);
@@ -753,12 +758,18 @@ int osmo_gsup_encode(struct msgb *msg, const struct osmo_gsup_message *gsup_msg)
 		}
 	}
 
-	for (idx = 0; idx < gsup_msg->num_auth_vectors; idx++) {
-		const struct osmo_auth_vector *auth_vector;
+	if (gsup_msg->message_type == OSMO_GSUP_MSGT_SEND_AUTH_INFO_REQUEST) {
+		uint8_t num = gsup_msg->num_auth_vectors;
+		if (num != 0)
+			msgb_tlv_put(msg, OSMO_GSUP_NUM_VECTORS_REQ_IE, 1, &num);
+	} else {
+		for (idx = 0; idx < gsup_msg->num_auth_vectors; idx++) {
+			const struct osmo_auth_vector *auth_vector;
 
-		auth_vector = &gsup_msg->auth_vectors[idx];
+			auth_vector = &gsup_msg->auth_vectors[idx];
 
-		encode_auth_info(msg, OSMO_GSUP_AUTH_TUPLE_IE, auth_vector);
+			encode_auth_info(msg, OSMO_GSUP_AUTH_TUPLE_IE, auth_vector);
+		}
 	}
 
 	if (gsup_msg->auts)
diff --git a/tests/gsup/gsup_test.c b/tests/gsup/gsup_test.c
index b84c88f0..f34ac7a6 100644
--- a/tests/gsup/gsup_test.c
+++ b/tests/gsup/gsup_test.c
@@ -19,6 +19,7 @@
 #define TEST_AN_APDU_IE 0x62, 0x05, 0x01, 0x42, 0x42, 0x42, 0x42
 #define TEST_SOURCE_NAME_IE 0x60, 0x05, 'M', 'S', 'C', '-', 'A'
 #define TEST_DESTINATION_NAME_IE 0x61, 0x05, 'M', 'S', 'C', '-', 'B'
+#define TEST_NUM_VEC_IE(x) 0x52, 1, x
 
 static void test_gsup_messages_dec_enc(void)
 {
@@ -32,6 +33,13 @@ static void test_gsup_messages_dec_enc(void)
 		TEST_CLASS_SUBSCR_IE
 	};
 
+	static const uint8_t send_auth_info_req10[] = {
+		0x08,
+		TEST_IMSI_IE,
+		TEST_NUM_VEC_IE(10),
+		TEST_CLASS_SUBSCR_IE
+	};
+
 	static const uint8_t send_auth_info_err[] = {
 		0x09,
 		TEST_IMSI_IE,
@@ -612,6 +620,8 @@ static void test_gsup_messages_dec_enc(void)
 			send_e_abort, sizeof(send_e_abort)},
 		{"E Routing Error",
 			send_e_routing_error, sizeof(send_e_routing_error)},
+		{"Send Authentication Info Request (10 Vectors)",
+			send_auth_info_req10, sizeof(send_auth_info_req10)},
 	};
 
 	printf("Test GSUP message decoding/encoding\n");
diff --git a/tests/gsup/gsup_test.err b/tests/gsup/gsup_test.err
index 1da39649..7b2fda97 100644
--- a/tests/gsup/gsup_test.err
+++ b/tests/gsup/gsup_test.err
@@ -115,6 +115,9 @@
   generated message: 4e 01 08 21 43 65 87 09 21 43 f5 30 04 de ad be ef 31 01 03 0a 01 04 60 05 4d 53 43 2d 41 61 05 4d 53 43 2d 42 
   original message:  4e 01 08 21 43 65 87 09 21 43 f5 30 04 de ad be ef 31 01 03 0a 01 04 60 05 4d 53 43 2d 41 61 05 4d 53 43 2d 42 
   IMSI:              123456789012345
+  generated message: 08 01 08 21 43 65 87 09 21 43 f5 52 01 0a 0a 01 01 
+  original message:  08 01 08 21 43 65 87 09 21 43 f5 52 01 0a 0a 01 01 
+  IMSI:              123456789012345
   message 0: tested 14 truncations, 13 parse failures
   message 1: tested 14 truncations, 13 parse failures
   message 2: tested 83 truncations, 81 parse failures
@@ -154,6 +157,7 @@
   message 36: tested 37 truncations, 32 parse failures
   message 37: tested 26 truncations, 22 parse failures
   message 38: tested 37 truncations, 32 parse failures
+  message 39: tested 17 truncations, 15 parse failures
 DLGSUP Stopping DLGSUP logging
   message 0: tested 3584 modifications, 771 parse failures
   message 1: tested 3584 modifications, 770 parse failures
@@ -194,3 +198,4 @@ DLGSUP Stopping DLGSUP logging
   message 36: tested 9472 modifications, 1803 parse failures
   message 37: tested 6656 modifications, 1546 parse failures
   message 38: tested 9472 modifications, 1803 parse failures
+  message 39: tested 4352 modifications, 1030 parse failures
diff --git a/tests/gsup/gsup_test.ok b/tests/gsup/gsup_test.ok
index db8bc2f6..ef2aec67 100644
--- a/tests/gsup/gsup_test.ok
+++ b/tests/gsup/gsup_test.ok
@@ -77,4 +77,6 @@ Test GSUP message decoding/encoding
           E Abort OK
   Testing E Routing Error
           E Routing Error OK
+  Testing Send Authentication Info Request (10 Vectors)
+          Send Authentication Info Request (10 Vectors) OK
 Done.