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
This commit is contained in:
Max 2018-02-15 11:42:11 +01:00
parent d55d7d4fc7
commit ebf149234e
3 changed files with 30 additions and 25 deletions

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@ -31,6 +31,7 @@ void gsm48_generate_lai(struct gsm48_loc_area_id *lai48, uint16_t mcc,
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,

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@ -584,37 +584,40 @@ int gsm48_generate_mid_from_tmsi(uint8_t *buf, uint32_t tmsi)
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

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@ -246,6 +246,7 @@ gsm48_encode_signal;
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;