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

3 files changed, 32 insertions, 10 deletions

diff --git a/TODO-RELEASE b/TODO-RELEASE
index 928b18d6..16496d68 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -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
\ No newline at end of file
+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
diff --git a/include/osmocom/gsm/gsm0480.h b/include/osmocom/gsm/gsm0480.h
index 05c26dfc..b0b6aa29 100644
--- a/include/osmocom/gsm/gsm0480.h
+++ b/include/osmocom/gsm/gsm0480.h
@@ -67,6 +67,18 @@ 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.
 	 */
diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
index 0072812d..38082b32 100644
--- a/src/gsm/gsm0480.c
+++ b/src/gsm/gsm0480.c
@@ -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;
 	}