LCLS, TS 48.008: add GCR IE encoding/decoding

* add functions to encode Global Call. Ref. from TS 29.205 as 3GPP TS
  48.008 §3.2.2.115 information element
* add corresponding tests

Change-Id: I82ce0207dc8de50689a8806c6471ad7fbae6219d

5 files changed, 123 insertions, 0 deletions

diff --git a/include/osmocom/gsm/gsm0808_utils.h b/include/osmocom/gsm/gsm0808_utils.h
index 5d5803be..22050b54 100644
--- a/include/osmocom/gsm/gsm0808_utils.h
+++ b/include/osmocom/gsm/gsm0808_utils.h
@@ -27,6 +27,7 @@ struct sockaddr_storage;
 
 #include <osmocom/gsm/protocol/gsm_08_08.h>
 #include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/gsm29205.h>
 #include <osmocom/gsm/gsm23003.h>
 #include <osmocom/gsm/gsm_utils.h>
 #include <osmocom/gsm/tlv.h>
@@ -82,6 +83,10 @@ uint8_t gsm0808_enc_aoip_trasp_addr(struct msgb *msg,
 				    const struct sockaddr_storage *ss);
 int gsm0808_dec_aoip_trasp_addr(struct sockaddr_storage *ss,
 				const uint8_t *elem, uint8_t len);
+
+uint8_t gsm0808_enc_gcr(struct msgb *msg, const struct osmo_gcr_parsed *g);
+int gsm0808_dec_gcr(struct osmo_gcr_parsed *g, const struct tlv_parsed *tp);
+
 uint8_t gsm0808_enc_speech_codec(struct msgb *msg,
 				 const struct gsm0808_speech_codec *sc);
 int gsm0808_dec_speech_codec(struct gsm0808_speech_codec *sc,
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c
index 38a8664c..a04addee 100644
--- a/src/gsm/gsm0808_utils.c
+++ b/src/gsm/gsm0808_utils.c
@@ -508,6 +508,41 @@ int gsm0808_dec_channel_type(struct gsm0808_channel_type *ct,
 	return (int)(elem - old_elem);
 }
 
+/*! Create BSSMAP Global Call Reference, 3GPP TS 48.008 §3.2.2.115.
+ *  \param[out] msg Message Buffer for appending IE
+ *  \param[in] g Global Call Reference, 3GPP TS 29.205 Table B 2.1.9.1
+ *  \returns number of bytes added to \a msg or 0 on error */
+uint8_t gsm0808_enc_gcr(struct msgb *msg, const struct osmo_gcr_parsed *g)
+{
+	uint8_t enc, *len = msgb_tl_put(msg, GSM0808_IE_GLOBAL_CALL_REF);
+
+	enc = osmo_enc_gcr(msg, g);
+	if (!enc)
+		return 0;
+
+	*len = enc;
+	return enc + 2; /* type (1 byte) + length (1 byte) */
+}
+
+/*! Decode BSSMAP Global Call Reference, 3GPP TS 29.205 Table B 2.1.9.1.
+ *  \param[out] gcr Caller-provided memory to store Global Call Reference
+ *  \param[in] elem IE value to be decoded
+ *  \param[in] len Length of \a elem in bytes
+ *  \returns number of bytes parsed; negative on error */
+int gsm0808_dec_gcr(struct osmo_gcr_parsed *gcr, const struct tlv_parsed *tp)
+{
+	int ret;
+	const uint8_t *buf = TLVP_VAL_MINLEN(tp, GSM0808_IE_GLOBAL_CALL_REF, OSMO_GCR_MIN_LEN);
+	if (!buf)
+		return -EINVAL;
+
+	ret = osmo_dec_gcr(gcr, buf, TLVP_LEN(tp, GSM0808_IE_GLOBAL_CALL_REF));
+	if (ret < 0)
+		return -ENOENT;
+
+	return 2 + ret;
+}
+
 /*! Encode TS 08.08 Encryption Information IE
  *  \param[out] msg Message Buffer to which IE is to be appended
  *  \param[in] ei Encryption Information to be encoded
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index e85ed6d4..94ae76a9 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -219,6 +219,8 @@ gsm0808_channel_type_name;
 gsm0808_lcls_config_names;
 gsm0808_lcls_control_names;
 gsm0808_lcls_status_names;
+gsm0808_enc_gcr;
+gsm0808_dec_gcr;
 
 gsm29118_msgb_alloc;
 gsm29118_create_alert_req;
diff --git a/tests/gsm0808/gsm0808_test.c b/tests/gsm0808/gsm0808_test.c
index 63b87200..f0f31654 100644
--- a/tests/gsm0808/gsm0808_test.c
+++ b/tests/gsm0808/gsm0808_test.c
@@ -22,6 +22,8 @@
 #include <osmocom/gsm/gsm0808_utils.h>
 #include <osmocom/gsm/protocol/gsm_08_08.h>
 #include <osmocom/gsm/protocol/gsm_08_58.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/application.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -597,6 +599,75 @@ static void test_prepend_dtap()
 	msgb_free(in_msg);
 }
 
+static void test_enc_dec_gcr()
+{
+	static const uint8_t res[] = {
+		GSM0808_IE_GLOBAL_CALL_REF,
+		0x0d, /* GCR length */
+		0x03, /* .net_len */
+		0xf1, 0xf2, 0xf3, /* .net */
+		0x02, /* .node length */
+		0xde, 0xad, /* .node */
+		0x05, /* length of Call. Ref. */
+		0x41, 0x42, 0x43, 0x44, 0x45 /* .cr - Call. Ref. */
+	};
+	uint8_t len;
+	struct msgb *msg;
+	struct osmo_gcr_parsed p = { 0 }, g = {
+		.net_len = 3,
+		.net = { 0xf1, 0xf2, 0xf3 },
+		.node = 0xDEAD,
+		.cr = { 0x41, 0x42, 0x43, 0x44, 0x45 },
+	};
+	int rc;
+	struct tlv_parsed tp;
+	msg = msgb_alloc_headroom(BSSMAP_MSG_SIZE, BSSMAP_MSG_HEADROOM, "global call reference");
+	if (!msg)
+		return;
+
+	len = gsm0808_enc_gcr(msg, &g);
+	printf("Testing Global Call Reference IE encoder...\n\t%d bytes added: %s\n",
+	       len, len == ARRAY_SIZE(res) ? "OK" : "FAIL");
+
+	if (!msgb_eq_data_print(msg, res, ARRAY_SIZE(res)))
+		abort();
+
+	rc = osmo_bssap_tlv_parse(&tp, msgb_data(msg), msgb_length(msg));
+	if (rc < 0) {
+		printf("parsing failed: %s [%s]\n", strerror(-rc), msgb_hexdump(msg));
+		abort();
+	}
+
+	rc = gsm0808_dec_gcr(&p, &tp);
+	if (rc < 0) {
+		printf("decoding failed: %s [%s]\n", strerror(-rc), msgb_hexdump(msg));
+		abort();
+	}
+
+	if (p.net_len != g.net_len) {
+		printf("Network ID length parsed wrong: %u != %u\n", p.net_len, g.net_len);
+		abort();
+	}
+
+	if (p.node != g.node) {
+		printf("Node ID parsed wrong: 0x%X != 0x%X\n", p.node, g.node);
+		abort();
+	}
+
+	if (memcmp(p.net, g.net, g.net_len) != 0) {
+		printf("Network ID parsed wrong: %s\n", osmo_hexdump(p.net, p.net_len));
+		abort();
+	}
+
+	if (memcmp(p.cr, g.cr, 5) != 0) {
+		printf("Call ref. ID parsed wrong: %s\n", osmo_hexdump(p.cr, 5));
+		abort();
+	}
+
+	printf("\tdecoded %d bytes: %s\n", rc, rc == len ? "OK" : "FAIL");
+	msgb_free(msg);
+}
+
 static void test_enc_dec_aoip_trasp_addr_v4()
 {
 	struct sockaddr_storage enc_addr;
@@ -1790,6 +1861,10 @@ void test_gsm48_mr_cfg_from_gsm0808_sc_cfg()
 
 int main(int argc, char **argv)
 {
+	void *ctx = talloc_named_const(NULL, 0, "gsm0808 test");
+	msgb_talloc_ctx_init(ctx, 0);
+	osmo_init_logging2(ctx, NULL);
+
 	printf("Testing generation of GSM0808 messages\n");
 	test_gsm0808_enc_cause();
 	test_create_layer3();
@@ -1813,6 +1888,9 @@ int main(int argc, char **argv)
 	test_create_paging();
 	test_create_dtap();
 	test_prepend_dtap();
+
+	test_enc_dec_gcr();
+
 	test_enc_dec_aoip_trasp_addr_v4();
 	test_enc_dec_aoip_trasp_addr_v6();
 	test_gsm0808_enc_dec_speech_codec();
diff --git a/tests/gsm0808/gsm0808_test.ok b/tests/gsm0808/gsm0808_test.ok
index e5833d01..d5857e32 100644
--- a/tests/gsm0808/gsm0808_test.ok
+++ b/tests/gsm0808/gsm0808_test.ok
@@ -22,6 +22,9 @@ Testing creating Clear Request
 Testing creating Paging Request
 Testing creating DTAP
 Testing prepend DTAP
+Testing Global Call Reference IE encoder...
+	15 bytes added: OK
+	decoded 15 bytes: OK
 test_gsm0808_enc_dec_cell_id_list_lac: encoded: 1a 07 05 01 24 ab cd 56 78 (rc = 9)
 ------- test_cell_id_list_add
      cell_id_list == CGI[0]:{}