diff options
author | Andreas Eversberg <jolly@eversberg.eu> | 2013-08-08 12:38:53 +0200 |
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committer | Holger Hans Peter Freyther <holger@moiji-mobile.com> | 2013-08-08 14:27:13 +0200 |
commit | 9597555a362cd28c02e9bbfe4f55c4b90ecdfa34 (patch) | |
tree | 819721bf3ee366ff6a333da64cb646519e1e0a2c /src/gsm/gsm48.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/gsm48.c')
0 files changed, 0 insertions, 0 deletions