gsm0480: Move the USSD parsing code to libosmocore
- Change u_int8 to uint8
- Change DEBUGP to LOGP
- Change fprintf(stderr, to LOGP(0, LOGL_DEBUG
- We should define log areas used inside libosmocore
diff --git a/src/gsm0480.c b/src/gsm0480.c
index ffcbc44..7d607a9 100644
--- a/src/gsm0480.c
+++ b/src/gsm0480.c
@@ -25,6 +25,9 @@
#include <osmocore/gsm0480.h>
#include <osmocore/gsm_utils.h>
+#include <osmocore/logging.h>
+
+#include <osmocore/protocol/gsm_04_08.h>
#include <osmocore/protocol/gsm_04_80.h>
#include <string.h>
@@ -188,3 +191,188 @@
return msg;
}
+/* Forward declarations */
+static int parse_ussd(uint8_t *ussd, struct ussd_request *req);
+static int parse_ussd_info_elements(uint8_t *ussd_ie,
+ struct ussd_request *req);
+static int parse_facility_ie(uint8_t *facility_ie, uint8_t length,
+ struct ussd_request *req);
+static int parse_ss_invoke(uint8_t *invoke_data, uint8_t length,
+ struct ussd_request *req);
+static int parse_process_uss_req(uint8_t *uss_req_data, uint8_t length,
+ struct ussd_request *req);
+
+/* Decode a mobile-originated USSD-request message */
+int gsm0480_decode_ussd_request(const struct msgb *msg, struct ussd_request *req)
+{
+ int rc = 0;
+ uint8_t *parse_ptr = msgb_l3(msg);
+
+ if ((*parse_ptr & 0x0F) == GSM48_PDISC_NC_SS) {
+ req->transaction_id = *parse_ptr & 0x70;
+ rc = parse_ussd(parse_ptr+1, req);
+ }
+
+ if (!rc)
+ LOGP(0, LOGL_DEBUG, "Error occurred while parsing received USSD!\n");
+
+ return rc;
+}
+
+static int parse_ussd(uint8_t *ussd, struct ussd_request *req)
+{
+ int rc = 1;
+ uint8_t msg_type = ussd[0] & 0xBF; /* message-type - section 3.4 */
+
+ switch (msg_type) {
+ case GSM0480_MTYPE_RELEASE_COMPLETE:
+ LOGP(0, LOGL_DEBUG, "USS Release Complete\n");
+ /* could also parse out the optional Cause/Facility data */
+ req->text[0] = 0xFF;
+ break;
+ case GSM0480_MTYPE_REGISTER:
+ case GSM0480_MTYPE_FACILITY:
+ rc &= parse_ussd_info_elements(ussd+1, req);
+ break;
+ default:
+ LOGP(0, LOGL_DEBUG, "Unknown GSM 04.80 message-type field 0x%02x\n",
+ ussd[0]);
+ rc = 0;
+ break;
+ }
+
+ return rc;
+}
+
+static int parse_ussd_info_elements(uint8_t *ussd_ie, struct ussd_request *req)
+{
+ int rc = -1;
+ /* Information Element Identifier - table 3.2 & GSM 04.08 section 10.5 */
+ uint8_t iei = ussd_ie[0];
+ uint8_t iei_length = ussd_ie[1];
+
+ switch (iei) {
+ case GSM48_IE_CAUSE:
+ break;
+ case GSM0480_IE_FACILITY:
+ rc = parse_facility_ie(ussd_ie+2, iei_length, req);
+ break;
+ case GSM0480_IE_SS_VERSION:
+ break;
+ default:
+ LOGP(0, LOGL_DEBUG, "Unhandled GSM 04.08 or 04.80 IEI 0x%02x\n",
+ iei);
+ rc = 0;
+ break;
+ }
+
+ return rc;
+}
+
+static int parse_facility_ie(uint8_t *facility_ie, uint8_t length,
+ struct ussd_request *req)
+{
+ int rc = 1;
+ uint8_t offset = 0;
+
+ do {
+ /* Component Type tag - table 3.7 */
+ uint8_t component_type = facility_ie[offset];
+ uint8_t component_length = facility_ie[offset+1];
+
+ switch (component_type) {
+ case GSM0480_CTYPE_INVOKE:
+ rc &= parse_ss_invoke(facility_ie+2,
+ component_length,
+ req);
+ break;
+ case GSM0480_CTYPE_RETURN_RESULT:
+ break;
+ case GSM0480_CTYPE_RETURN_ERROR:
+ break;
+ case GSM0480_CTYPE_REJECT:
+ break;
+ default:
+ LOGP(0, LOGL_DEBUG, "Unknown GSM 04.80 Facility "
+ "Component Type 0x%02x\n", component_type);
+ rc = 0;
+ break;
+ }
+ offset += (component_length+2);
+ } while (offset < length);
+
+ return rc;
+}
+
+/* Parse an Invoke component - see table 3.3 */
+static int parse_ss_invoke(uint8_t *invoke_data, uint8_t length,
+ struct ussd_request *req)
+{
+ int rc = 1;
+ uint8_t offset;
+
+ /* mandatory part */
+ if (invoke_data[0] != GSM0480_COMPIDTAG_INVOKE_ID) {
+ LOGP(0, LOGL_DEBUG, "Unexpected GSM 04.80 Component-ID tag "
+ "0x%02x (expecting Invoke ID tag)\n", invoke_data[0]);
+ }
+
+ offset = invoke_data[1] + 2;
+ req->invoke_id = invoke_data[2];
+
+ /* optional part */
+ if (invoke_data[offset] == GSM0480_COMPIDTAG_LINKED_ID)
+ offset += invoke_data[offset+1] + 2; /* skip over it */
+
+ /* mandatory part */
+ if (invoke_data[offset] == GSM0480_OPERATION_CODE) {
+ uint8_t operation_code = invoke_data[offset+2];
+ switch (operation_code) {
+ case GSM0480_OP_CODE_PROCESS_USS_REQ:
+ rc = parse_process_uss_req(invoke_data + offset + 3,
+ length - offset - 3,
+ req);
+ break;
+ default:
+ LOGP(0, LOGL_DEBUG, "GSM 04.80 operation code 0x%02x "
+ "is not yet handled\n", operation_code);
+ rc = 0;
+ break;
+ }
+ } else {
+ LOGP(0, LOGL_DEBUG, "Unexpected GSM 04.80 Component-ID tag 0x%02x "
+ "(expecting Operation Code tag)\n",
+ invoke_data[0]);
+ rc = 0;
+ }
+
+ return rc;
+}
+
+/* Parse the parameters of a Process UnstructuredSS Request */
+static int parse_process_uss_req(uint8_t *uss_req_data, uint8_t length,
+ struct ussd_request *req)
+{
+ int rc = 0;
+ int num_chars;
+ uint8_t dcs;
+
+ if (uss_req_data[0] == GSM_0480_SEQUENCE_TAG) {
+ if (uss_req_data[2] == ASN1_OCTET_STRING_TAG) {
+ dcs = uss_req_data[4];
+ if ((dcs == 0x0F) &&
+ (uss_req_data[5] == ASN1_OCTET_STRING_TAG)) {
+ num_chars = (uss_req_data[6] * 8) / 7;
+ /* Prevent a mobile-originated buffer-overrun! */
+ if (num_chars > MAX_LEN_USSD_STRING)
+ num_chars = MAX_LEN_USSD_STRING;
+ gsm_7bit_decode(req->text,
+ &(uss_req_data[7]), num_chars);
+ /* append null-terminator */
+ req->text[num_chars+1] = 0;
+ rc = 1;
+ }
+ }
+ }
+ return rc;
+}