diff options
author | Holger Hans Peter Freyther <zecke@selfish.org> | 2009-08-20 08:41:24 +0200 |
---|---|---|
committer | Holger Hans Peter Freyther <zecke@selfish.org> | 2009-08-20 13:59:14 +0200 |
commit | 5d0e56f722ce77ed29226c85e93dd09c9184f97e (patch) | |
tree | 51a3767c861603d1e317053ec5687cced1c86e21 /openbsc/src/gsm_04_08_utils.c | |
parent | d1862d7cf98b984407d8533ac68b0ae85cfbf9c7 (diff) |
[gsm48] Introduce a gsm48_generate_mid_from_imsi method
Prefix generate_mid_from_tmsi with a gsm48_, create a new method
to binary encode the imsi. Add a unit test for parsing and decoding.
The implementation can parse the data it generated and the
last octet seems to be filled with the end mark.
Diffstat (limited to 'openbsc/src/gsm_04_08_utils.c')
-rw-r--r-- | openbsc/src/gsm_04_08_utils.c | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/openbsc/src/gsm_04_08_utils.c b/openbsc/src/gsm_04_08_utils.c index e771ea3b2..c62f04d57 100644 --- a/openbsc/src/gsm_04_08_utils.c +++ b/openbsc/src/gsm_04_08_utils.c @@ -164,6 +164,12 @@ static char bcd2char(u_int8_t bcd) return 'A' + (bcd - 0xa); } +/* only works for numbers in ascci */ +static u_int8_t char2bcd(char c) +{ + return c - 0x30; +} + void gsm0408_generate_lai(struct gsm48_loc_area_id *lai48, u_int16_t mcc, u_int16_t mnc, u_int16_t lac) @@ -187,7 +193,7 @@ void gsm0408_generate_lai(struct gsm48_loc_area_id *lai48, u_int16_t mcc, lai48->lac = htons(lac); } -int generate_mid_from_tmsi(u_int8_t *buf, u_int32_t tmsi) +int gsm48_generate_mid_from_tmsi(u_int8_t *buf, u_int32_t tmsi) { u_int32_t *tptr = (u_int32_t *) &buf[3]; @@ -199,6 +205,35 @@ int generate_mid_from_tmsi(u_int8_t *buf, u_int32_t tmsi) return 7; } +int gsm48_generate_mid_from_imsi(u_int8_t *buf, const char *imsi) +{ + unsigned int length = strlen(imsi), i, off = 0; + u_int8_t odd = (length & 0x1) == 1; + + buf[0] = GSM48_IE_MOBILE_ID; + buf[2] = 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) { + u_int8_t lower, upper; + + lower = char2bcd(imsi[++off]); + if (!odd && off + 1 == length) + upper = 0x0f; + else + upper = char2bcd(imsi[++off]) & 0x0f; + + buf[2 + i] = (upper << 4) | lower; + } + + return 2 + buf[1]; +} + /* Section 9.1.8 / Table 9.9 */ struct chreq { u_int8_t val; |