Add generic Mobile Identity encoder
Add generic function which allows caller to set Mobile Identity
explicitly. This allows to use IMEI or IMEISV for example. Make
gsm48_generate_mid_from_imsi() into wrapper around new function.
Change-Id: Id79be7abfff75ecd0d248bbeed93e605abeec9b3
diff --git a/include/osmocom/gsm/gsm48.h b/include/osmocom/gsm/gsm48.h
index 69431de..9ec5463 100644
--- a/include/osmocom/gsm/gsm48.h
+++ b/include/osmocom/gsm/gsm48.h
@@ -31,6 +31,7 @@
uint16_t mnc, uint16_t lac);
int gsm48_generate_mid_from_tmsi(uint8_t *buf, uint32_t tmsi);
int gsm48_generate_mid_from_imsi(uint8_t *buf, const char *imsi);
+uint8_t gsm48_generate_mid(uint8_t *buf, const char *id, uint8_t mi_type);
/* Convert Mobile Identity (10.5.1.4) to string */
int gsm48_mi_to_string(char *string, const int str_len,
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index 4570802..b58e9e2 100644
--- a/src/gsm/gsm48.c
+++ b/src/gsm/gsm48.c
@@ -584,37 +584,40 @@
return 7;
}
+/*! Generate TS 24.008 §10.5.1.4 Mobile ID
+ * \param[out] buf Caller-provided output buffer
+ * \param[in] id Identity to be encoded
+ * \returns number of bytes used in \a buf */
+uint8_t gsm48_generate_mid(uint8_t *buf, const char *id, uint8_t mi_type)
+{
+ uint8_t length = strnlen(id, 255), i, off = 0, odd = (length & 1) == 1;
+
+ buf[0] = GSM48_IE_MOBILE_ID;
+ buf[2] = osmo_char2bcd(id[0]) << 4 | mi_type | (odd << 3);
+
+ /* if the length is even we will fill half of the last octet */
+ buf[1] = (length + (odd ? 1 : 2)) >> 1;
+
+ for (i = 1; i < buf[1]; ++i) {
+ uint8_t upper, lower = osmo_char2bcd(id[++off]);
+ if (!odd && off + 1 == length)
+ upper = 0x0f;
+ else
+ upper = osmo_char2bcd(id[++off]) & 0x0f;
+
+ buf[2 + i] = (upper << 4) | lower;
+ }
+
+ return 2 + buf[1];
+}
+
/*! Generate TS 04.08 Mobile ID from IMSI
* \param[out] buf Caller-provided output buffer
* \param[in] imsi IMSI to be encoded
* \returns number of bytes used in \a buf */
int gsm48_generate_mid_from_imsi(uint8_t *buf, const char *imsi)
{
- unsigned int length = strlen(imsi), i, off = 0;
- uint8_t odd = (length & 0x1) == 1;
-
- buf[0] = GSM48_IE_MOBILE_ID;
- buf[2] = osmo_char2bcd(imsi[0]) << 4 | GSM_MI_TYPE_IMSI | (odd << 3);
-
- /* if the length is even we will fill half of the last octet */
- if (odd)
- buf[1] = (length + 1) >> 1;
- else
- buf[1] = (length + 2) >> 1;
-
- for (i = 1; i < buf[1]; ++i) {
- uint8_t lower, upper;
-
- lower = osmo_char2bcd(imsi[++off]);
- if (!odd && off + 1 == length)
- upper = 0x0f;
- else
- upper = osmo_char2bcd(imsi[++off]) & 0x0f;
-
- buf[2 + i] = (upper << 4) | lower;
- }
-
- return 2 + buf[1];
+ return gsm48_generate_mid(buf, imsi, GSM_MI_TYPE_IMSI);
}
/*! Convert TS 04.08 Mobile Identity (10.5.1.4) to string
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 53b6f6e..7a74718 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -246,6 +246,7 @@
gsm48_encode_ssversion;
gsm48_encode_useruser;
gsm48_generate_lai;
+gsm48_generate_mid;
gsm48_generate_mid_from_imsi;
gsm48_generate_mid_from_tmsi;
gsm48_mi_to_string;