Add function to properly encode RAI
Add gsm48_encode_ra() which takes appropriate struct as [out] parameter
instead of generic buffer. Using uint8_t buffer instead of proper struct
type prooved to be error-prone - see Coverity CID57877, CID57876.
Old gsm48_construct_ra() is made into tiny wrapper around new
function. The test output is adjusted because of the change in function
return value which was constant and hence ignored anyway.
Related: OS#1640
Change-Id: I31f9605277f4945f207c2c44ff82e62399f8db74
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index a7daea4..8876059 100644
--- a/src/gsm/gsm48.c
+++ b/src/gsm/gsm48.c
@@ -689,33 +689,34 @@
raid->rac = buf[5];
}
+/*! Encode a 3GPP TS 24.008 § 10.5.5.15 Routing area identification
+ * \param[out] out Caller-provided packed struct
+ * \param[in] raid Routing Area ID to be encoded
+ */
+void gsm48_encode_ra(struct gsm48_ra_id *out, const struct gprs_ra_id *raid)
+{
+ out->lac = osmo_htons(raid->lac);
+ out->rac = raid->rac;
+
+ out->digits[0] = ((raid->mcc / 100) % 10) | (((raid->mcc / 10) % 10) << 4);
+ out->digits[1] = raid->mcc % 10;
+
+ if (raid->mnc < 100) {
+ out->digits[1] |= 0xf0;
+ out->digits[2] = ((raid->mnc / 10) % 10) | ((raid->mnc % 10) << 4);
+ } else {
+ out->digits[1] |= (raid->mnc % 10) << 4;
+ out->digits[2] = ((raid->mnc / 100) % 10) | (((raid->mnc / 10) % 10) << 4);
+ }
+}
+
/*! Encode a TS 04.08 Routing Area Identifier
* \param[out] buf Caller-provided output buffer of 6 bytes
* \param[in] raid Routing Area ID to be encoded
* \returns number of bytes used in \a buf */
int gsm48_construct_ra(uint8_t *buf, const struct gprs_ra_id *raid)
{
- uint16_t mcc = raid->mcc;
- uint16_t mnc = raid->mnc;
- uint16_t _lac;
-
- buf[0] = ((mcc / 100) % 10) | (((mcc / 10) % 10) << 4);
- buf[1] = (mcc % 10);
-
- /* I wonder who came up with the stupidity of encoding the MNC
- * differently depending on how many digits its decimal number has! */
- if (mnc < 100) {
- buf[1] |= 0xf0;
- buf[2] = ((mnc / 10) % 10) | ((mnc % 10) << 4);
- } else {
- buf[1] |= (mnc % 10) << 4;
- buf[2] = ((mnc / 100) % 10) | (((mnc / 10) % 10) << 4);
- }
-
- _lac = osmo_htons(raid->lac);
- memcpy(buf + 3, &_lac, 2);
-
- buf[5] = raid->rac;
+ gsm48_encode_ra((struct gsm48_ra_id *)buf, raid);
return 6;
}
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index d915234..5611ba3 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -205,6 +205,7 @@
gsm48_rr_msg_name;
gsm48_cc_state_name;
gsm48_construct_ra;
+gsm48_encode_ra;
gsm48_hdr_gmm_cipherable;
gsm48_decode_bcd_number;
gsm48_decode_bearer_cap;