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 /include | |
| 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 'include')
| -rw-r--r-- | include/osmocom/gsm/gsm_utils.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/osmocom/gsm/gsm_utils.h b/include/osmocom/gsm/gsm_utils.h index a572f504..6cd46e45 100644 --- a/include/osmocom/gsm/gsm_utils.h +++ b/include/osmocom/gsm/gsm_utils.h @@ -57,8 +57,10 @@ const char *gsm_band_name(enum gsm_band band); enum gsm_band gsm_band_parse(const char *mhz); int gsm_7bit_decode(char *decoded, const uint8_t *user_data, uint8_t length); +int gsm_7bit_decode_ussd(char *decoded, const uint8_t *user_data, uint8_t length); int gsm_7bit_decode_hdr(char *decoded, const uint8_t *user_data, uint8_t length, uint8_t ud_hdr_ind); int gsm_7bit_encode(uint8_t *result, const char *data); +int gsm_7bit_encode_ussd(uint8_t *result, const char *data, int *octets_written); int gsm_7bit_encode_oct(uint8_t *result, const char *data, int *octets_written); /* the three functions below are helper functions and here for the unit test */ |