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osmo-ttcn3-hacks
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fix f_enc_IMEI_L3() oddevenIndicator 

f_gen_imei() calls f_enc_IMEI_L3() with a 14 digits argument, but the IMEI_L3
template used is hardcoded to 15 digits. So the oddevenIndicator must always
indicate odd, not depend on the digits argument.

f_gen_imei() should probably also compose a Luhn checksum, leaving that to
another patch.

Found by using the new osmo_mobile_identity API in osmo-msc, which is stricter
about odd/even and filler digits than our previous implementations.
See osmo-msc Idfc8e576e10756aeaacf5569f6178068313eb7ea .

Change-Id: Iaa9ba1214c4c15fd9620e68fe2e842fdf52912c0
This commit is contained in:
Neels Hofmeyr 2020-06-10 17:31:18 +02:00 committed by neels
parent 15a8501232
commit 1661781611
1 changed files with 14 additions and 5 deletions
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19
library/L3_Templates.ttcn
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@ -184,11 +184,20 @@ private function f_enc_IMSI_L3(hexstring digits) return IMSI_L3 {
private function f_enc_IMEI_L3(hexstring digits) return IMEI_L3 {
var IMEI_L3 l3;
var integer len := lengthof(digits);
if (len rem 2 == 1) { /* modulo remainder */
l3.oddevenIndicator := '1'B;
} else {
l3.oddevenIndicator := '0'B;
}
/* IMEI_L3 is always 15 digits. That is actually a 14 digit IMEI + a Luhn checksum digit (see
* libosmocore/include/osmocom/gsm/protocol/gsm_23_003.h)
*
* Here, we must not make the oddevenIndicator depend on the 'digits' parameter, because:
* - The IMEI_L3 template assumes always 15 digits.
* - The 'digits' parameter, however, may also contain less digits, 14 in the case of
* f_gen_imei().
* - The IMEI_L3 template will then fill up with zeros to make 15 digits.
* Hence oddevenIndicator must always indicate 'odd' == '1'B.
*
* FIXME: if the caller passes less than 15 digits, the Luhn checksum digit then ends up zero == most probably
* wrong.
*/
l3.oddevenIndicator := '1'B;
l3.digits := digits;
return l3;
}