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gsm0480: copy the raw USSD data, its DCS and length 

As it was already documented before, the 'ss_request' struct has
a rudiment of deprecated 'ussd_request' struct - the 'ussd_text'
field. It represents the data either of an INVOKE component,
either of a RETURN_RESULT component, encoded as ASCII in case
if DCS is 0x0f (i.e. decoded by the code itself), otherwise
raw bytes 'as is'.

Previously, there was no possibility to distinguish between
ASCII and raw bytes with different DCS. Moreover, the payload
decoding is not desired in some cases.

Let's introduce the new fields, which will carry the raw
unmodified payload, its length and DCS (Data Coding Scheme).

Change-Id: Ia193d175021e145bb3b131290231f307dbefc64a
This commit is contained in:
Vadim Yanitskiy 2018-04-04 10:34:41 +07:00
parent 9fb7e3a9fb
commit a24ead0126
3 changed files with 32 additions and 10 deletions
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4
TODO-RELEASE
View File

@ -10,4 +10,6 @@
core msgb_queue_free() add inline func to msgb.h
coding gsm0503_rach_ext-encode() add func to gsm0503_coding.h
codec ecu.c / ecu.h implement ECU for FR (Error Concealment Unit)
fsm fsmc / fsm.h added callback for graceful exit => ABI changed
fsm fsmc / fsm.h added callback for graceful exit => ABI changed
gsm gsm0480.c / gsm0480.h the 'ss_request' struct extended with ussd_data,
ussd_data_len, and ussd_data_dcs => ABI changed

12
include/osmocom/gsm/gsm0480.h
View File

@ -66,6 +66,18 @@ struct ss_request {
*/
uint8_t ussd_text[GSM0480_USSD_OCTET_STRING_LEN];
/**
* Represents the data of either an INVOKE, either
* a RETURN_RESULT component 'as is'. Useful when
* decoding is not supported or not desired.
*
* Shall be always followed by its length (in bytes)
* and DCS (Data Coding Scheme).
*/
uint8_t ussd_data[GSM0480_USSD_OCTET_STRING_LEN];
uint8_t ussd_data_len; /* Length in bytes */
uint8_t ussd_data_dcs; /* Data Coding Scheme */
/**
* GSM TS 04.80, section 3.3 "Transaction identifier"
* See GSM TS 04.07, section 11.2.3 for details.

26
src/gsm/gsm0480.c
View File

@ -557,6 +557,11 @@ static int parse_process_uss_data(const uint8_t *uss_req_data, uint16_t length,
memcpy(req->ussd_text, uss_req_data + 2, num_chars);
/* Copy the data 'as is' */
memcpy(req->ussd_data, uss_req_data + 2, num_chars);
req->ussd_data_len = num_chars;
req->ussd_data_dcs = 0x00;
return 1;
}
@ -580,6 +585,17 @@ static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length,
/* Get DCS (Data Coding Scheme) */
dcs = uss_req_data[4];
/* Get the amount of bytes */
num_chars = uss_req_data[6];
/* Prevent a mobile-originated buffer-overrun! */
if (num_chars > GSM0480_USSD_OCTET_STRING_LEN)
num_chars = GSM0480_USSD_OCTET_STRING_LEN;
/* Copy the data 'as is' */
memcpy(req->ussd_data, uss_req_data + 7, num_chars);
req->ussd_data_len = num_chars;
req->ussd_data_dcs = dcs;
/**
* According to GSM 04.08, 4.4.2 "ASN.1 data types":
@ -588,7 +604,7 @@ static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length,
*/
if (dcs == 0x0F) {
/* Calculate the amount of 7-bit characters */
num_chars = (uss_req_data[6] * 8) / 7;
num_chars = (num_chars * 8) / 7;
/* Prevent a mobile-originated buffer-overrun! */
if (num_chars > GSM0480_USSD_7BIT_STRING_LEN)
@ -599,15 +615,7 @@ static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length,
return 1;
} else {
/* Get the amount of 8-bit characters */
num_chars = uss_req_data[6];
/* Prevent a mobile-originated buffer-overrun! */
if (num_chars > GSM0480_USSD_OCTET_STRING_LEN)
num_chars = GSM0480_USSD_OCTET_STRING_LEN;
memcpy(req->ussd_text, &(uss_req_data[7]), num_chars);
return 1;
}