From 6eafe9137ca345078531fc607a461f397faa505b Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Fri, 16 Oct 2009 08:32:58 +0200 Subject: Add USDD code from Mike Haben This is the initial checkin of the USSD code from Mike Haben. I didn't put it in the main branch as I think it still needs some cleanup. --- openbsc/src/gsm_04_80.c | 306 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 306 insertions(+) create mode 100644 openbsc/src/gsm_04_80.c (limited to 'openbsc/src/gsm_04_80.c') diff --git a/openbsc/src/gsm_04_80.c b/openbsc/src/gsm_04_80.c new file mode 100644 index 000000000..d0dcbc2c3 --- /dev/null +++ b/openbsc/src/gsm_04_80.c @@ -0,0 +1,306 @@ +/* GSM Mobile Radio Interface Layer 3 messages on the A-bis interface + * 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0 */ + +/* (C) 2008-2009 by Harald Welte + * (C) 2008, 2009 by Holger Hans Peter Freyther + * (C) 2009 by Mike Haben + * + * 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 +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +static char ussd_string_buff[32]; +static u_int8_t last_transaction_id; +static u_int8_t last_invoke_id; + +/* Forward declarations */ +static int parse_ussd(u_int8_t *ussd); +static int parse_ussd_information_elements(u_int8_t *ussd_ie); +static int parse_facility_ie(u_int8_t *facility_ie, u_int8_t length); +static int parse_ss_invoke(u_int8_t *invoke_data, u_int8_t length); +static int parse_process_uss_req(u_int8_t *uss_req_data, u_int8_t length); + +static inline unsigned char *msgb_wrap_with_TL(struct msgb *msgb, u_int8_t tag) +{ + msgb->data -= 2; + msgb->data[0] = tag; + msgb->data[1] = msgb->len; + msgb->len += 2; + return msgb->data; +} + +static inline unsigned char *msgb_push_TLV1(struct msgb *msgb, u_int8_t tag, u_int8_t value) +{ + msgb->data -= 3; + msgb->len += 3; + msgb->data[0] = tag; + msgb->data[1] = 1; + msgb->data[2] = value; + return msgb->data; +} + + +/* Receive a mobile-originated USSD message and return the decoded text */ +char* gsm0480_rcv_ussd(struct msgb *msg) +{ + int rc = 0; + u_int8_t* parse_ptr = msgb_l3(msg); + + memset(ussd_string_buff, 0, sizeof(ussd_string_buff)); + + if ((*parse_ptr & 0x0F) == GSM48_PDISC_NC_SS) { + last_transaction_id = *parse_ptr & 0x70; + rc = parse_ussd(parse_ptr + 1); + } + + if (!rc) + DEBUGP(DMM, "Error occurred while parsing received USSD!\n"); + + return ussd_string_buff; +} + +static int parse_ussd(u_int8_t *ussd) +{ + int rc = 1; + u_int8_t msg_type = ussd[0] & 0xBF; /* message-type - section 3.4 */ + + switch(msg_type) { + case GSM0480_MTYPE_RELEASE_COMPLETE: + DEBUGP(DMM, "USS Release Complete\n"); /* could also parse out the optional Cause/Facility data */ + ussd_string_buff[0] = 0xFF; + break; + case GSM0480_MTYPE_REGISTER: + case GSM0480_MTYPE_FACILITY: + rc &= parse_ussd_information_elements(ussd+1); + break; + default: + fprintf(stderr, "Unknown GSM 04.80 message-type field 0x%02x\n", + ussd[0]); + rc = 0; + break; + } + + return rc; +} + +static int parse_ussd_information_elements(u_int8_t *ussd_ie) +{ + int rc; + + u_int8_t iei = ussd_ie[0]; /* Information Element Identifier - table 3.2 & GSM 04.08 section 10.5 */ + u_int8_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); + break; + case GSM0480_IE_SS_VERSION: + break; + default: + fprintf(stderr, "Unhandled GSM 04.08 or 04.80 Information Element Identifier 0x%02x\n", + iei); + rc = 0; + break; + } + + return rc; +} + +static int parse_facility_ie(u_int8_t *facility_ie, u_int8_t length) +{ + int rc = 1; + u_int8_t offset = 0; + + do { + u_int8_t component_type = facility_ie[offset]; /* Component Type tag - table 3.7 */ + u_int8_t component_length = facility_ie[offset+1]; + switch(component_type) { + case GSM0480_CTYPE_INVOKE: + rc &= parse_ss_invoke(facility_ie+2, component_length); + break; + case GSM0480_CTYPE_RETURN_RESULT: + break; + case GSM0480_CTYPE_RETURN_ERROR: + break; + case GSM0480_CTYPE_REJECT: + break; + default: + fprintf(stderr, "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(u_int8_t *invoke_data, u_int8_t length) +{ + int rc = 1; + + if (invoke_data[0] != GSM0480_COMPIDTAG_INVOKE_ID) { /* mandatory part */ + fprintf(stderr, "Unexpected GSM 04.80 Component-ID tag 0x%02x (expecting Invoke ID tag)\n", + invoke_data[0]); + } + u_int8_t offset = invoke_data[1] + 2; + last_invoke_id = invoke_data[2]; + + if (invoke_data[offset] == GSM0480_COMPIDTAG_LINKED_ID) /* optional part */ + offset += invoke_data[offset+1] + 2; /* skip over it */ + + if (invoke_data[offset] == GSM0480_OPERATION_CODE) { /* mandatory part */ + u_int8_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); + break; + default: + fprintf(stderr, "GSM 04.80 operation code 0x%02x is not yet handled\n", + operation_code); + rc = 0; + break; + } + } else { + fprintf(stderr, "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(u_int8_t *uss_req_data, u_int8_t length) +{ + int rc = 1; + int num_chars; + u_int8_t dcs; + + /* FIXME: most phones send USSD text as a 7-bit encoded octet string; the following code + also handles the case of plain ASCII text (IA5String), but other encodings might be used */ + 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; + gsm_7bit_decode(ussd_string_buff, &(uss_req_data[7]), num_chars); + } + } + } else if (uss_req_data[0] == ASN1_IA5_STRING_TAG) { + num_chars = uss_req_data[1]; + memcpy(ussd_string_buff, &(uss_req_data[2]), num_chars); + } + + return rc; +} + +/* Send response to a mobile-originated ProcessUnstructuredSS-Request */ +int gsm0480_send_ussd_response(struct msgb *in_msg, const char* response_text) +{ + struct msgb *msg = gsm48_msgb_alloc(); + struct gsm48_hdr *gh; + u_int8_t *ptr8; + int response_len; + + response_len = (strlen(response_text) * 7) / 8; + if (((strlen(response_text) * 7) % 8) != 0) + response_len += 1; + + msg->bts_link = in_msg->bts_link; + msg->lchan = in_msg->lchan; + + /* First put the payload text into the message */ + ptr8 = msgb_put(msg, response_len); + gsm_7bit_encode(ptr8, response_text); + + /* 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, last_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 | last_transaction_id | (1<<7); /* TI direction = 1 */ + gh->msg_type = GSM0480_MTYPE_RELEASE_COMPLETE; + + return gsm48_sendmsg(msg, NULL); +} + +int gsm0480_send_ussd_reject(struct msgb *in_msg) +{ + struct msgb *msg = gsm48_msgb_alloc(); + struct gsm48_hdr *gh; + + msg->bts_link = in_msg->bts_link; + msg->lchan = in_msg->lchan; + + /* First insert the problem code */ + msgb_push_TLV1(msg, GSM_0480_PROBLEM_CODE_TAG_GENERAL, GSM_0480_GEN_PROB_CODE_UNRECOGNISED); + + /* Before it insert the invoke ID */ + msgb_push_TLV1(msg, GSM0480_COMPIDTAG_INVOKE_ID, last_invoke_id); + + /* Wrap this up as a Reject component */ + msgb_wrap_with_TL(msg, GSM0480_CTYPE_REJECT); + + /* 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 | last_transaction_id | (1<<7); /* TI direction = 1 */ + gh->msg_type = GSM0480_MTYPE_RELEASE_COMPLETE; + + return gsm48_sendmsg(msg, NULL); +} -- cgit v1.2.3