The 7bit<->8bit encoding/decoding functions didn't check whether
there is still enough space in the destination buffer. Therefore a
buffer size parameter has been added to each of the functions which
is used to truncate the output if the buffer is too small.
In addition, the return value of the decoding functions has been
changed to number of characters written (excluding \0), so this
value is always equal to strlen(decoded).
The old functions are still available as wrapper functions.
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>
This reverts commit f996b05dbd
and 2b0cac4ef8. A detailed
explanation can be found here:
http://lists.osmocom.org/pipermail/openbsc/2013-July/004737.html
The short description is that:
1.) The API should return (as out parameter) the number of
octets used.
2.) The handling for the <CR> encoding only applies to USSD
and it is incomplete. On top of that it broke the SMS test.
This patch moves all GSM-specific definitions to include/osmocom/gsm.
Moreover, the headers in include/osmocore/ have been moved to
include/osmocom/core.
This has been proposed by Harald Welte and Sylvain Munaunt.
Tested with `make distcheck'.
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
libosmogsm which is provided by libosmocore.
I have also moved generate_backtrace() to backtrace.c instead
of gsm_utils.c, otherwise the timer and msgfile tests depend on
libosmogsm.
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
Alexander Huemer
Jacob Erlbeck