diff options
| author | Andreas Eversberg <jolly@eversberg.eu> | 2013-08-08 12:38:53 +0200 |
|---|---|---|
| committer | Holger Hans Peter Freyther <holger@moiji-mobile.com> | 2013-08-08 14:27:13 +0200 |
| commit | 9597555a362cd28c02e9bbfe4f55c4b90ecdfa34 (patch) | |
| tree | 819721bf3ee366ff6a333da64cb646519e1e0a2c /src/gsm/gsm0480.c | |
| parent | 6bfa7445fca074fdf94707681d93e92ec0993bbd (diff) | |
Add special 7-bit encoding and decoding functions for USSD coding
Handling 7-bit coding is a little different for USSD, as TS 03.38
states:
To avoid the situation where the receiving entity confuses 7 binary
zero pad bits as the @ character, the carriage return or <CR>
character shall be used for padding in this situation [...].
If <CR> is intended to be the last character and the message
(including the wanted <CR>) ends on an octet boundary, then another
<CR> must be added together with a padding bit 0. The receiving entity
will perform the carriage return function twice, but this will not
result in misoperation as the definition of <CR> [...] is identical to
the definition of <CR><CR>.
The receiving entity shall remove the final <CR> character where the
message ends on an octet boundary with <CR> as the last character.
Jacob has verified the fix with fakeBTS and the wireshark dissector.
Fixes: OW#947
Reviewed-by: Jacob Erlbeck <jerlbeck@sysmocom.de>
Diffstat (limited to 'src/gsm/gsm0480.c')
| -rw-r--r-- | src/gsm/gsm0480.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c index b9b3ed97..cc693feb 100644 --- a/src/gsm/gsm0480.c +++ b/src/gsm/gsm0480.c @@ -105,7 +105,7 @@ struct msgb *gsm0480_create_unstructuredSS_Notify(int alertPattern, const char * msgb_put_u8(msg, ASN1_OCTET_STRING_TAG); ussd_len_ptr = msgb_put(msg, 1); data = msgb_put(msg, 0); - len = gsm_7bit_encode(data, text); + gsm_7bit_encode_ussd(data, text, &len); msgb_put(msg, len); ussd_len_ptr[0] = len; /* USSD-String } */ @@ -172,7 +172,7 @@ struct msgb *gsm0480_create_notifySS(const char *text) msgb_put_u8(msg, 0x82); tmp_len = msgb_put(msg, 1); data = msgb_put(msg, 0); - len = gsm_7bit_encode(data, text); + gsm_7bit_encode_ussd(data, text, &len); tmp_len[0] = len; msgb_put(msg, len); @@ -401,8 +401,8 @@ static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length, /* Prevent a mobile-originated buffer-overrun! */ if (num_chars > MAX_LEN_USSD_STRING) num_chars = MAX_LEN_USSD_STRING; - gsm_7bit_decode(req->text, - &(uss_req_data[7]), num_chars); + gsm_7bit_decode_ussd(req->text, + &(uss_req_data[7]), num_chars); rc = 1; } } @@ -423,7 +423,7 @@ struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const /* First put the payload text into the message */ ptr8 = msgb_put(msg, 0); - response_len = gsm_7bit_encode(ptr8, text); + gsm_7bit_encode_ussd(ptr8, text, &response_len); msgb_put(msg, response_len); /* Then wrap it as an Octet String */ |