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 ยง3.2.2.115 information element
* add corresponding tests
Change-Id: I82ce0207dc8de50689a8806c6471ad7fbae6219d
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c
index 38a8664..a04adde 100644
--- a/src/gsm/gsm0808_utils.c
+++ b/src/gsm/gsm0808_utils.c
@@ -508,6 +508,41 @@
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