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-rw-r--r--src/gsm/gsm0480.c461
1 files changed, 461 insertions, 0 deletions
diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
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+/* Format functions for GSM 04.80 */
+
+/*
+ * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009 by Mike Haben <michael.haben@btinternet.com>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#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>
+
+static inline unsigned char *msgb_wrap_with_TL(struct msgb *msgb, uint8_t tag)
+{
+ uint8_t *data = msgb_push(msgb, 2);
+
+ data[0] = tag;
+ data[1] = msgb->len - 2;
+ return data;
+}
+
+static inline unsigned char *msgb_push_TLV1(struct msgb *msgb, uint8_t tag,
+ uint8_t value)
+{
+ uint8_t *data = msgb_push(msgb, 3);
+
+ data[0] = tag;
+ data[1] = 1;
+ data[2] = value;
+ return data;
+}
+
+/* wrap an invoke around it... the other way around
+ *
+ * 1.) Invoke Component tag
+ * 2.) Invoke ID Tag
+ * 3.) Operation
+ * 4.) Data
+ */
+int gsm0480_wrap_invoke(struct msgb *msg, int op, int link_id)
+{
+ /* 3. operation */
+ msgb_push_TLV1(msg, GSM0480_OPERATION_CODE, op);
+
+ /* 2. invoke id tag */
+ msgb_push_TLV1(msg, GSM0480_COMPIDTAG_INVOKE_ID, link_id);
+
+ /* 1. component tag */
+ msgb_wrap_with_TL(msg, GSM0480_CTYPE_INVOKE);
+
+ return 0;
+}
+
+/* wrap the GSM 04.08 Facility IE around it */
+int gsm0480_wrap_facility(struct msgb *msg)
+{
+ msgb_wrap_with_TL(msg, GSM0480_IE_FACILITY);
+
+ return 0;
+}
+
+struct msgb *gsm0480_create_unstructuredSS_Notify(int alertPattern, const char *text)
+{
+ struct msgb *msg;
+ uint8_t *seq_len_ptr, *ussd_len_ptr, *data;
+ int len;
+
+ msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
+ if (!msg)
+ return NULL;
+
+ /* SEQUENCE { */
+ msgb_put_u8(msg, GSM_0480_SEQUENCE_TAG);
+ seq_len_ptr = msgb_put(msg, 1);
+
+ /* DCS { */
+ msgb_put_u8(msg, ASN1_OCTET_STRING_TAG);
+ msgb_put_u8(msg, 1);
+ msgb_put_u8(msg, 0x0F);
+ /* } DCS */
+
+ /* USSD-String { */
+ msgb_put_u8(msg, ASN1_OCTET_STRING_TAG);
+ ussd_len_ptr = msgb_put(msg, 1);
+ data = msgb_put(msg, 0);
+ len = gsm_7bit_encode(data, text);
+ msgb_put(msg, len);
+ ussd_len_ptr[0] = len;
+ /* USSD-String } */
+
+ /* alertingPattern { */
+ msgb_put_u8(msg, ASN1_OCTET_STRING_TAG);
+ msgb_put_u8(msg, 1);
+ msgb_put_u8(msg, alertPattern);
+ /* } alertingPattern */
+
+ seq_len_ptr[0] = 3 + 2 + ussd_len_ptr[0] + 3;
+ /* } SEQUENCE */
+
+ return msg;
+}
+
+struct msgb *gsm0480_create_notifySS(const char *text)
+{
+ struct msgb *msg;
+ uint8_t *data, *tmp_len;
+ uint8_t *seq_len_ptr, *cal_len_ptr, *opt_len_ptr, *nam_len_ptr;
+ int len;
+
+ len = strlen(text);
+ if (len < 1 || len > 160)
+ return NULL;
+
+ msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
+ if (!msg)
+ return NULL;
+
+ msgb_put_u8(msg, GSM_0480_SEQUENCE_TAG);
+ seq_len_ptr = msgb_put(msg, 1);
+
+ /* ss_code for CNAP { */
+ msgb_put_u8(msg, 0x81);
+ msgb_put_u8(msg, 1);
+ msgb_put_u8(msg, 0x19);
+ /* } ss_code */
+
+
+ /* nameIndicator { */
+ msgb_put_u8(msg, 0xB4);
+ nam_len_ptr = msgb_put(msg, 1);
+
+ /* callingName { */
+ msgb_put_u8(msg, 0xA0);
+ opt_len_ptr = msgb_put(msg, 1);
+ msgb_put_u8(msg, 0xA0);
+ cal_len_ptr = msgb_put(msg, 1);
+
+ /* namePresentationAllowed { */
+ /* add the DCS value */
+ msgb_put_u8(msg, 0x80);
+ msgb_put_u8(msg, 1);
+ msgb_put_u8(msg, 0x0F);
+
+ /* add the lengthInCharacters */
+ msgb_put_u8(msg, 0x81);
+ msgb_put_u8(msg, 1);
+ msgb_put_u8(msg, strlen(text));
+
+ /* add the actual string */
+ msgb_put_u8(msg, 0x82);
+ tmp_len = msgb_put(msg, 1);
+ data = msgb_put(msg, 0);
+ len = gsm_7bit_encode(data, text);
+ tmp_len[0] = len;
+ msgb_put(msg, len);
+
+ /* }; namePresentationAllowed */
+
+ cal_len_ptr[0] = 3 + 3 + 2 + len;
+ opt_len_ptr[0] = cal_len_ptr[0] + 2;
+ /* }; callingName */
+
+ nam_len_ptr[0] = opt_len_ptr[0] + 2;
+ /* ); nameIndicator */
+
+ /* write the lengths... */
+ seq_len_ptr[0] = 3 + nam_len_ptr[0] + 2;
+
+ return msg;
+}
+
+/* Forward declarations */
+static int parse_ussd(const struct gsm48_hdr *hdr,
+ uint16_t len, struct ussd_request *req);
+static int parse_ussd_info_elements(const uint8_t *ussd_ie, uint16_t len,
+ struct ussd_request *req);
+static int parse_facility_ie(const uint8_t *facility_ie, uint16_t length,
+ struct ussd_request *req);
+static int parse_ss_invoke(const uint8_t *invoke_data, uint16_t length,
+ struct ussd_request *req);
+static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length,
+ struct ussd_request *req);
+
+/* Decode a mobile-originated USSD-request message */
+int gsm0480_decode_ussd_request(const struct gsm48_hdr *hdr, uint16_t len,
+ struct ussd_request *req)
+{
+ int rc = 0;
+
+ if (len < sizeof(*hdr) + 2) {
+ LOGP(0, LOGL_DEBUG, "USSD Request is too short.\n");
+ return 0;
+ }
+
+ if ((hdr->proto_discr & 0x0f) == GSM48_PDISC_NC_SS) {
+ req->transaction_id = hdr->proto_discr & 0x70;
+ rc = parse_ussd(hdr, len, req);
+ }
+
+ if (!rc)
+ LOGP(0, LOGL_DEBUG, "Error occurred while parsing received USSD!\n");
+
+ return rc;
+}
+
+static int parse_ussd(const struct gsm48_hdr *hdr, uint16_t len, struct ussd_request *req)
+{
+ int rc = 1;
+ uint8_t msg_type = hdr->msg_type & 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(&hdr->data[0], len - sizeof(*hdr), req);
+ break;
+ default:
+ LOGP(0, LOGL_DEBUG, "Unknown GSM 04.80 message-type field 0x%02x\n",
+ hdr->msg_type);
+ rc = 0;
+ break;
+ }
+
+ return rc;
+}
+
+static int parse_ussd_info_elements(const uint8_t *ussd_ie, uint16_t len,
+ struct ussd_request *req)
+{
+ int rc = -1;
+ /* Information Element Identifier - table 3.2 & GSM 04.08 section 10.5 */
+ uint8_t iei;
+ uint8_t iei_length;
+
+ iei = ussd_ie[0];
+ iei_length = ussd_ie[1];
+
+ /* If the data does not fit, report an error */
+ if (len - 2 < iei_length)
+ return 0;
+
+ 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(const uint8_t *facility_ie, uint16_t length,
+ struct ussd_request *req)
+{
+ int rc = 1;
+ uint8_t offset = 0;
+
+ while (offset + 2 <= length) {
+ /* Component Type tag - table 3.7 */
+ uint8_t component_type = facility_ie[offset];
+ uint8_t component_length = facility_ie[offset+1];
+
+ /* size check */
+ if (offset + 2 + component_length > length) {
+ LOGP(0, LOGL_ERROR, "Component does not fit.\n");
+ return 0;
+ }
+
+ 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);
+ };
+
+ return rc;
+}
+
+/* Parse an Invoke component - see table 3.3 */
+static int parse_ss_invoke(const uint8_t *invoke_data, uint16_t length,
+ struct ussd_request *req)
+{
+ int rc = 1;
+ uint8_t offset;
+
+ if (length < 3)
+ return 0;
+
+ /* 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];
+
+ /* look ahead once */
+ if (offset + 1 > length)
+ return 0;
+
+ /* 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) {
+ if (offset + 2 > length)
+ return 0;
+ 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(const uint8_t *uss_req_data, uint16_t length,
+ struct ussd_request *req)
+{
+ int rc = 0;
+ int num_chars;
+ uint8_t dcs;
+
+
+ /* we need at least that much */
+ if (length < 8)
+ return 0;
+
+
+ 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);
+ rc = 1;
+ }
+ }
+ }
+ return rc;
+}
+
+struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const char *text)
+{
+ struct msgb *msg;
+ struct gsm48_hdr *gh;
+ uint8_t *ptr8;
+ int response_len;
+
+ msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
+ if (!msg)
+ return NULL;
+
+ /* First put the payload text into the message */
+ ptr8 = msgb_put(msg, 0);
+ response_len = gsm_7bit_encode(ptr8, text);
+ msgb_put(msg, response_len);
+
+ /* Then wrap it as an Octet String */
+ msgb_wrap_with_TL(msg, ASN1_OCTET_STRING_TAG);
+
+ /* Pre-pend the DCS octet string */
+ msgb_push_TLV1(msg, ASN1_OCTET_STRING_TAG, 0x0F);
+
+ /* Then wrap these as a Sequence */
+ msgb_wrap_with_TL(msg, GSM_0480_SEQUENCE_TAG);
+
+ /* Pre-pend the operation code */
+ msgb_push_TLV1(msg, GSM0480_OPERATION_CODE,
+ GSM0480_OP_CODE_PROCESS_USS_REQ);
+
+ /* Wrap the operation code and IA5 string as a sequence */
+ msgb_wrap_with_TL(msg, GSM_0480_SEQUENCE_TAG);
+
+ /* Pre-pend the invoke ID */
+ msgb_push_TLV1(msg, GSM0480_COMPIDTAG_INVOKE_ID, invoke_id);
+
+ /* Wrap this up as a Return Result component */
+ msgb_wrap_with_TL(msg, GSM0480_CTYPE_RETURN_RESULT);
+
+ /* Wrap the component in a Facility message */
+ msgb_wrap_with_TL(msg, GSM0480_IE_FACILITY);
+
+ /* And finally pre-pend the L3 header */
+ gh = (struct gsm48_hdr *) msgb_push(msg, sizeof(*gh));
+ gh->proto_discr = GSM48_PDISC_NC_SS | trans_id
+ | (1<<7); /* TI direction = 1 */
+ gh->msg_type = GSM0480_MTYPE_RELEASE_COMPLETE;
+
+ return msg;
+}