| /* 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 <osmocom/gsm/gsm0480.h> |
| #include <osmocom/gsm/gsm_utils.h> |
| |
| #include <osmocom/core/logging.h> |
| |
| #include <osmocom/gsm/protocol/gsm_04_08.h> |
| #include <osmocom/gsm/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); |
| gsm_7bit_encode_n_ussd(data, msgb_tailroom(msg), text, &len); |
| 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); |
| gsm_7bit_encode_n_ussd(data, msgb_tailroom(msg), text, &len); |
| 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_ss(const struct gsm48_hdr *hdr, |
| uint16_t len, struct ss_request *req); |
| static int parse_ss_info_elements(const uint8_t *ussd_ie, uint16_t len, |
| struct ss_request *req); |
| static int parse_facility_ie(const uint8_t *facility_ie, uint16_t length, |
| struct ss_request *req); |
| static int parse_ss_invoke(const uint8_t *invoke_data, uint16_t length, |
| struct ss_request *req); |
| static int parse_process_uss_req(const uint8_t *uss_req_data, uint16_t length, |
| struct ss_request *req); |
| static int parse_ss_for_bs_req(const uint8_t *ss_req_data, |
| uint16_t length, |
| struct ss_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) |
| { |
| struct ss_request ss; |
| int rc = 0; |
| |
| memset(&ss, 0, sizeof(ss)); |
| |
| 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; |
| |
| ss.transaction_id = req->transaction_id; |
| rc = parse_ss(hdr, len, &ss); |
| |
| /* convert from ss_request to legacy ussd_request */ |
| req->transaction_id = ss.transaction_id; |
| req->invoke_id = ss.invoke_id; |
| if (ss.ussd_text[0] == 0xFF) |
| req->text[0] = '\0'; |
| else { |
| memcpy(req->text, ss.ussd_text, sizeof(req->text)); |
| req->text[sizeof(req->text)-1] = '\0'; |
| } |
| } |
| |
| if (!rc) |
| LOGP(0, LOGL_DEBUG, "Error occurred while parsing received USSD!\n"); |
| |
| return rc; |
| } |
| |
| /* Decode a mobile-originated SS request message */ |
| int gsm0480_decode_ss_request(const struct gsm48_hdr *hdr, uint16_t len, |
| struct ss_request *req) |
| { |
| int rc = 0; |
| |
| if (len < sizeof(*hdr) + 2) { |
| LOGP(0, LOGL_DEBUG, "SS 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_ss(hdr, len, req); |
| } |
| |
| if (!rc) |
| LOGP(0, LOGL_DEBUG, "Error occurred while parsing received SS!\n"); |
| |
| return rc; |
| } |
| |
| static int parse_ss(const struct gsm48_hdr *hdr, uint16_t len, struct ss_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, "SS Release Complete\n"); |
| /* could also parse out the optional Cause/Facility data */ |
| req->ussd_text[0] = 0xFF; |
| break; |
| case GSM0480_MTYPE_REGISTER: |
| case GSM0480_MTYPE_FACILITY: |
| rc &= parse_ss_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_ss_info_elements(const uint8_t *ss_ie, uint16_t len, |
| struct ss_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 = ss_ie[0]; |
| iei_length = ss_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(ss_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 ss_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 ss_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]; |
| req->opcode = operation_code; |
| switch (operation_code) { |
| case GSM0480_OP_CODE_PROCESS_USS_REQ: |
| rc = parse_process_uss_req(invoke_data + offset + 3, |
| length - offset - 3, |
| req); |
| break; |
| case GSM0480_OP_CODE_ACTIVATE_SS: |
| case GSM0480_OP_CODE_DEACTIVATE_SS: |
| case GSM0480_OP_CODE_INTERROGATE_SS: |
| rc = parse_ss_for_bs_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 ss_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_n_ussd((char *)req->ussd_text, |
| sizeof(req->ussd_text), |
| &(uss_req_data[7]), num_chars); |
| rc = 1; |
| } |
| } |
| } |
| return rc; |
| } |
| |
| /* Parse the parameters of a Interrogate/Activate/DeactivateSS Request */ |
| static int parse_ss_for_bs_req(const uint8_t *ss_req_data, |
| uint16_t length, |
| struct ss_request *req) |
| { |
| int rc = 0; |
| |
| |
| /* we need at least that much */ |
| if (length < 5) |
| return 0; |
| |
| |
| if (ss_req_data[0] == GSM_0480_SEQUENCE_TAG) { |
| if ((ss_req_data[2] == ASN1_OCTET_STRING_TAG) && |
| ss_req_data[3] == 1) { |
| req->ss_code = ss_req_data[4]; |
| |
| 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); |
| gsm_7bit_encode_n_ussd(ptr8, msgb_tailroom(msg), text, &response_len); |
| 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; |
| } |