add osmo_mi_name(), for MI-to-string like "IMSI-123456"

We have gsm48_mi_to_string() and osmo_bcd2str(), but still lack a function that
conveniently prints both MI type and value in one function call.

Related: http://people.osmocom.org/neels/mi_mi_mi.jpg
Change-Id: I7798c3ef983c2e333b2b9cbffef6f366f370bd81

5 files changed, 82 insertions, 0 deletions

diff --git a/include/osmocom/gsm/gsm48.h b/include/osmocom/gsm/gsm48.h
index 2b14e6cd..0f5727a0 100644
--- a/include/osmocom/gsm/gsm48.h
+++ b/include/osmocom/gsm/gsm48.h
@@ -53,6 +53,7 @@ uint8_t gsm48_generate_mid(uint8_t *buf, const char *id, uint8_t mi_type);
 int gsm48_mi_to_string(char *string, const int str_len,
 			const uint8_t *mi, const int mi_len);
 const char *gsm48_mi_type_name(uint8_t mi);
+const char *osmo_mi_name(const uint8_t *mi, uint8_t mi_len);
 
 /* Parse Routeing Area Identifier */
 void gsm48_parse_ra(struct gprs_ra_id *raid, const uint8_t *buf);
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index 190622ff..853ea513 100644
--- a/src/gsm/gsm48.c
+++ b/src/gsm/gsm48.c
@@ -433,6 +433,42 @@ const char *gsm48_mi_type_name(uint8_t mi)
 	return get_value_string(mi_type_names, mi);
 }
 
+/*! Return a human readable representation of a Mobile Identity in static buffer.
+ * \param[in] mi  Mobile Identity buffer containing 3GPP TS 04.08 style MI type and data.
+ * \param[in] mi_len  Length of mi.
+ * \return A string like "IMSI-1234567", "TMSI-0x1234ABCD" or "unknown", "TMSI-invalid"...
+ */
+const char *osmo_mi_name(const uint8_t *mi, uint8_t mi_len)
+{
+	static char mi_name[10 + GSM48_MI_SIZE + 1];
+	uint8_t mi_type;
+	uint32_t tmsi;
+	char mi_string[GSM48_MI_SIZE];
+
+	mi_type = (mi && mi_len) ? (mi[0] & GSM_MI_TYPE_MASK) : GSM_MI_TYPE_NONE;
+
+	switch (mi_type) {
+	case GSM_MI_TYPE_TMSI:
+		/* Table 10.5.4.3, reverse generate_mid_from_tmsi */
+		if (mi_len == GSM48_TMSI_LEN && mi[0] == (0xf0 | GSM_MI_TYPE_TMSI)) {
+			tmsi = osmo_load32be(&mi[1]);
+			snprintf(mi_name, sizeof(mi_name), "TMSI-0x%08" PRIX32, tmsi);
+			return mi_name;
+		}
+		return "TMSI-invalid";
+
+	case GSM_MI_TYPE_IMSI:
+	case GSM_MI_TYPE_IMEI:
+	case GSM_MI_TYPE_IMEISV:
+		osmo_bcd2str(mi_string, sizeof(mi_string), mi, 1, (mi_len * 2) - (mi[0] & GSM_MI_ODD ? 0 : 1), true);
+		snprintf(mi_name, sizeof(mi_name), "%s-%s", gsm48_mi_type_name(mi_type), mi_string);
+		return mi_name;
+
+	default:
+		return "unknown";
+	}
+}
+
 /*! Checks is particular message is cipherable in A/Gb mode according to
  *         3GPP TS 24.008 § 4.7.1.2
  *  \param[in] hdr Message header
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index bb978786..8b7a1641 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -325,6 +325,7 @@ gsm48_rr_att_tlvdef;
 gsm48_set_dtx;
 gsm48_dtx_mode;
 gsm48_mi_type_name;
+osmo_mi_name;
 gsm48_mcc_mnc_to_bcd;
 gsm48_mcc_mnc_from_bcd;
 gsm48_generate_lai2;
diff --git a/tests/gsm0408/gsm0408_test.c b/tests/gsm0408/gsm0408_test.c
index 9bb320d0..37ef3f15 100644
--- a/tests/gsm0408/gsm0408_test.c
+++ b/tests/gsm0408/gsm0408_test.c
@@ -355,6 +355,7 @@ static void test_mid_from_imsi(void)
 struct test_mid_encode_decode_test {
 	uint8_t mi_type;
 	const char *mi_str;
+	const char *mi_name;
 	size_t str_size;
 	const char *expect_mi_tlv_hex;
 	const char *expect_str;
@@ -365,31 +366,37 @@ static const struct test_mid_encode_decode_test test_mid_encode_decode_tests[] =
 	{
 		.mi_type = GSM_MI_TYPE_IMSI,
 		.mi_str = "123456789012345",
+		.mi_name = "IMSI-123456789012345",
 		.expect_mi_tlv_hex = "17081932547698103254",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMSI,
 		.mi_str = "12345678901234",
+		.mi_name = "IMSI-12345678901234",
 		.expect_mi_tlv_hex = "170811325476981032f4",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMSI,
 		.mi_str = "423423",
+		.mi_name = "IMSI-423423",
 		.expect_mi_tlv_hex = "1704413224f3",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMSI | GSM_MI_ODD,
 		.mi_str = "423423",
+		.mi_name = "IMSI-423423",
 		.expect_mi_tlv_hex = "1704413224f3",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMSI,
 		.mi_str = "4234235",
+		.mi_name = "IMSI-4234235",
 		.expect_mi_tlv_hex = "170449322453",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMSI,
 		.mi_str = "4234235",
+		.mi_name = "IMSI-4234235",
 		.expect_mi_tlv_hex = "170449322453",
 		.str_size = 4,
 		.expect_str = "423",
@@ -397,26 +404,31 @@ static const struct test_mid_encode_decode_test test_mid_encode_decode_tests[] =
 	{
 		.mi_type = GSM_MI_TYPE_IMEI,
 		.mi_str = "123456789012345",
+		.mi_name = "IMEI-123456789012345",
 		.expect_mi_tlv_hex = "17081a32547698103254",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMEI,
 		.mi_str = "98765432109876",
+		.mi_name = "IMEI-98765432109876",
 		.expect_mi_tlv_hex = "170892785634129078f6",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMEI,
 		.mi_str = "987654321098765",
+		.mi_name = "IMEI-987654321098765",
 		.expect_mi_tlv_hex = "17089a78563412907856",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMEISV,
 		.mi_str = "987654321098765432",
+		.mi_name = "IMEI-SV-987654321098765432",
 		.expect_mi_tlv_hex = "170a937856341290785634f2",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_IMEISV,
 		.mi_str = "987654321098765432",
+		.mi_name = "IMEI-SV-987654321098765432",
 		.expect_mi_tlv_hex = "170a937856341290785634f2",
 		.str_size = 16,
 		.expect_str = "987654321098765",
@@ -425,18 +437,21 @@ static const struct test_mid_encode_decode_test test_mid_encode_decode_tests[] =
 		/* gsm48 treats TMSI as decimal string */
 		.mi_type = GSM_MI_TYPE_TMSI,
 		.mi_str = "305419896", /* 0x12345678 as decimal */
+		.mi_name = "TMSI-0x12345678",
 		.expect_mi_tlv_hex = "1705f412345678",
 		.expect_rc = 9, /* exception: gsm48_mi_to_string() for TMSI returns strlen(), not bytes! */
 	},
 	{
 		.mi_type = GSM_MI_TYPE_TMSI,
 		.mi_str = "12648430", /* 0xc0ffee as decimal */
+		.mi_name = "TMSI-0x00C0FFEE",
 		.expect_mi_tlv_hex = "1705f400c0ffee",
 		.expect_rc = 8, /* exception: gsm48_mi_to_string() for TMSI returns strlen(), not bytes! */
 	},
 	{
 		.mi_type = GSM_MI_TYPE_TMSI,
 		.mi_str = "0",
+		.mi_name = "TMSI-0x00000000",
 		.expect_mi_tlv_hex = "1705f400000000",
 		.expect_rc = 1, /* exception: gsm48_mi_to_string() for TMSI returns strlen(), not bytes! */
 	},
@@ -444,6 +459,7 @@ static const struct test_mid_encode_decode_test test_mid_encode_decode_tests[] =
 		/* gsm48 treats TMSI as decimal string */
 		.mi_type = GSM_MI_TYPE_TMSI,
 		.mi_str = "305419896", /* 0x12345678 as decimal */
+		.mi_name = "TMSI-0x12345678",
 		.expect_mi_tlv_hex = "1705f412345678",
 		.str_size = 5,
 		.expect_str = "3054",
@@ -452,18 +468,21 @@ static const struct test_mid_encode_decode_test test_mid_encode_decode_tests[] =
 	{
 		.mi_type = GSM_MI_TYPE_NONE,
 		.mi_str = "123",
+		.mi_name = "unknown",
 		.expect_mi_tlv_hex = "17021832", /* encoding invalid MI type */
 		.expect_str = "",
 	},
 	{
 		.mi_type = GSM_MI_TYPE_NONE,
 		.mi_str = "1234",
+		.mi_name = "unknown",
 		.expect_mi_tlv_hex = "17031032f4", /* encoding invalid MI type */
 		.expect_str = "",
 	},
 	{
 		.mi_type = GSM_MI_ODD,
 		.mi_str = "1234",
+		.mi_name = "unknown",
 		.expect_mi_tlv_hex = "17031032f4", /* encoding invalid MI type */
 		.expect_str = "",
 	},
@@ -512,6 +531,13 @@ static void test_mid_encode_decode(void)
 		if (rc != expect_rc)
 			printf("     ERROR: expected rc=%d\n", expect_rc);
 
+		if (t->mi_name) {
+			const char *mi_name = osmo_mi_name(mi_buf, mi_len);
+			printf("  -> MI-name=%s\n", osmo_quote_str(mi_name, -1));
+			if (strcmp(mi_name, t->mi_name))
+				printf("     ERROR: expected MI-name=%s\n", osmo_quote_str(t->mi_name, -1));
+		}
+
 		/* Now make sure the resulting string is always '\0' terminated.
 		 * The above started out with a zeroed buffer, now repeat with a tainted one. */
 		str_len = strlen(str);
diff --git a/tests/gsm0408/gsm0408_test.ok b/tests/gsm0408/gsm0408_test.ok
index d6579e50..0c135558 100644
--- a/tests/gsm0408/gsm0408_test.ok
+++ b/tests/gsm0408/gsm0408_test.ok
@@ -7,57 +7,75 @@ Testing Mobile Identity conversions
 - IMSI 123456789012345
   -> MI-TLV-hex='17081932547698103254'
   -> MI-str="123456789012345" rc=16
+  -> MI-name="IMSI-123456789012345"
 - IMSI 12345678901234
   -> MI-TLV-hex='170811325476981032f4'
   -> MI-str="12345678901234" rc=15
+  -> MI-name="IMSI-12345678901234"
 - IMSI 423423
   -> MI-TLV-hex='1704413224f3'
   -> MI-str="423423" rc=7
+  -> MI-name="IMSI-423423"
 - unknown 0x9 423423
   -> MI-TLV-hex='1704413224f3'
   -> MI-str="423423" rc=7
+  -> MI-name="IMSI-423423"
 - IMSI 4234235
   -> MI-TLV-hex='170449322453'
   -> MI-str="4234235" rc=8
+  -> MI-name="IMSI-4234235"
 - IMSI 4234235
   -> MI-TLV-hex='170449322453'
   -> MI-str="423" rc=4
+  -> MI-name="IMSI-4234235"
 - IMEI 123456789012345
   -> MI-TLV-hex='17081a32547698103254'
   -> MI-str="123456789012345" rc=16
+  -> MI-name="IMEI-123456789012345"
 - IMEI 98765432109876
   -> MI-TLV-hex='170892785634129078f6'
   -> MI-str="98765432109876" rc=15
+  -> MI-name="IMEI-98765432109876"
 - IMEI 987654321098765
   -> MI-TLV-hex='17089a78563412907856'
   -> MI-str="987654321098765" rc=16
+  -> MI-name="IMEI-987654321098765"
 - IMEI-SV 987654321098765432
   -> MI-TLV-hex='170a937856341290785634f2'
   -> MI-str="987654321098765432" rc=19
+  -> MI-name="IMEI-SV-987654321098765432"
 - IMEI-SV 987654321098765432
   -> MI-TLV-hex='170a937856341290785634f2'
   -> MI-str="987654321098765" rc=16
+  -> MI-name="IMEI-SV-987654321098765432"
 - TMSI 305419896
   -> MI-TLV-hex='1705f412345678'
   -> MI-str="305419896" rc=9
+  -> MI-name="TMSI-0x12345678"
 - TMSI 12648430
   -> MI-TLV-hex='1705f400c0ffee'
   -> MI-str="12648430" rc=8
+  -> MI-name="TMSI-0x00C0FFEE"
 - TMSI 0
   -> MI-TLV-hex='1705f400000000'
   -> MI-str="0" rc=1
+  -> MI-name="TMSI-0x00000000"
 - TMSI 305419896
   -> MI-TLV-hex='1705f412345678'
   -> MI-str="3054" rc=9
+  -> MI-name="TMSI-0x12345678"
 - NONE 123
   -> MI-TLV-hex='17021832'
   -> MI-str="" rc=1
+  -> MI-name="unknown"
 - NONE 1234
   -> MI-TLV-hex='17031032f4'
   -> MI-str="" rc=1
+  -> MI-name="unknown"
 - unknown 0x8 1234
   -> MI-TLV-hex='17031032f4'
   -> MI-str="" rc=1
+  -> MI-name="unknown"
 
 Decoding zero length Mobile Identities
 - MI type: IMSI