Harald Welte | 7d29d59 | 2018-07-28 22:00:08 +0200 | [diff] [blame] | 1 | /* osmo-demo-euse: An External USSD Entity (EUSE) for demo purpose */ |
| 2 | |
| 3 | /* (C) 2018 by Harald Welte <laforge@gnumonks.org> |
| 4 | * |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU Affero General Public License as published by |
| 9 | * the Free Software Foundation; either version 3 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU Affero General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Affero General Public License |
| 18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 19 | */ |
| 20 | |
| 21 | /* |
| 22 | * This program illustrates how to implement an external USSD application using |
| 23 | * the existing osmocom libraries, particularly libosmocore, libosmogsm and libosmo-gsup-client. |
| 24 | * |
| 25 | * It will receive any MS-originated USSD message that is routed to it via the HLR, and |
| 26 | * simply respond it quoted in the following string: 'You sent "foobar"' (assuming the original |
| 27 | * message was 'foobar'). |
| 28 | */ |
| 29 | |
| 30 | #include <string.h> |
| 31 | #include <stdio.h> |
| 32 | #include <errno.h> |
| 33 | #include <signal.h> |
| 34 | |
| 35 | #include <osmocom/core/msgb.h> |
| 36 | #include <osmocom/core/select.h> |
| 37 | #include <osmocom/core/application.h> |
| 38 | #include <osmocom/core/utils.h> |
| 39 | #include <osmocom/core/logging.h> |
| 40 | |
| 41 | #include <osmocom/gsm/gsup.h> |
| 42 | #include <osmocom/gsm/gsm0480.h> |
| 43 | #include <osmocom/gsm/protocol/gsm_04_80.h> |
| 44 | |
| 45 | #include <osmocom/gsupclient/gsup_client.h> |
| 46 | |
Neels Hofmeyr | 2f75803 | 2019-11-20 00:37:07 +0100 | [diff] [blame] | 47 | #include <osmocom/hlr/logging.h> |
Harald Welte | 7d29d59 | 2018-07-28 22:00:08 +0200 | [diff] [blame] | 48 | |
| 49 | static struct osmo_gsup_client *g_gc; |
| 50 | |
| 51 | /*! send a SS/USSD response to a given imsi/session. |
| 52 | * \param[in] gsupc GSUP client connection through which to send |
| 53 | * \param[in] imsi IMSI of the subscriber |
| 54 | * \param[in] session_id Unique identifier of SS session for which this response is |
| 55 | * \param[in] gsup_msg_type GSUP message type (OSMO_GSUP_MSGT_PROC_SS_{REQUEST,RESULT,ERROR}) |
| 56 | * \param[in] final Is this the final result (true=END) or an intermediate result (false=CONTINUE) |
| 57 | * \param[in] msg Optional binary/BER encoded SS date (for FACILITY IE). Can be NULL. Freed in |
| 58 | * this function call. |
| 59 | */ |
| 60 | static int euse_tx_ss(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id, |
| 61 | enum osmo_gsup_message_type gsup_msg_type, bool final, struct msgb *ss_msg) |
| 62 | { |
| 63 | struct osmo_gsup_message resp = {0}; |
| 64 | struct msgb *resp_msg; |
| 65 | |
| 66 | switch (gsup_msg_type) { |
| 67 | case OSMO_GSUP_MSGT_PROC_SS_REQUEST: |
| 68 | case OSMO_GSUP_MSGT_PROC_SS_RESULT: |
| 69 | case OSMO_GSUP_MSGT_PROC_SS_ERROR: |
| 70 | break; |
| 71 | default: |
| 72 | msgb_free(ss_msg); |
| 73 | return -EINVAL; |
| 74 | } |
| 75 | |
| 76 | resp.message_type = gsup_msg_type; |
| 77 | OSMO_STRLCPY_ARRAY(resp.imsi, imsi); |
| 78 | if (final) |
| 79 | resp.session_state = OSMO_GSUP_SESSION_STATE_END; |
| 80 | else |
| 81 | resp.session_state = OSMO_GSUP_SESSION_STATE_CONTINUE; |
| 82 | resp.session_id = session_id; |
| 83 | if (ss_msg) { |
| 84 | resp.ss_info = msgb_data(ss_msg); |
| 85 | resp.ss_info_len = msgb_length(ss_msg); |
| 86 | } |
| 87 | |
| 88 | resp_msg = gsm0480_msgb_alloc_name(__func__); |
| 89 | OSMO_ASSERT(resp_msg); |
| 90 | osmo_gsup_encode(resp_msg, &resp); |
| 91 | msgb_free(ss_msg); |
| 92 | return osmo_gsup_client_send(gsupc, resp_msg); |
| 93 | } |
| 94 | |
| 95 | /*! send a SS/USSD reject to a given IMSI/session. |
| 96 | * \param[in] gsupc GSUP client connection through which to send |
| 97 | * \param[in] imsi IMSI of the subscriber |
| 98 | * \param[in] session_id Unique identifier of SS session for which this response is |
| 99 | * \param[in] invoke_id InvokeID of the request |
| 100 | * \param[in] problem_tag Problem code tag (table 3.13) |
| 101 | * \param[in] problem_code Problem code (table 3.14-3.17) |
| 102 | */ |
| 103 | static int euse_tx_ussd_reject(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id, |
| 104 | int invoke_id, uint8_t problem_tag, uint8_t problem_code) |
| 105 | { |
| 106 | struct msgb *msg = gsm0480_gen_reject(invoke_id, problem_tag, problem_code); |
| 107 | LOGP(DMAIN, LOGL_NOTICE, "Tx %s/0x%08x: Reject(%d, 0x%02x, 0x%02x)\n", imsi, session_id, |
| 108 | invoke_id, problem_tag, problem_code); |
| 109 | OSMO_ASSERT(msg); |
| 110 | return euse_tx_ss(gsupc, imsi, session_id, OSMO_GSUP_MSGT_PROC_SS_RESULT, true, msg); |
| 111 | } |
| 112 | |
| 113 | /*! send a SS/USSD response in 7-bit GSM default alphabet o a given imsi/session. |
| 114 | * \param[in] gsupc GSUP client connection through which to send |
| 115 | * \param[in] imsi IMSI of the subscriber |
| 116 | * \param[in] session_id Unique identifier of SS session for which this response is |
| 117 | * \param[in] final Is this the final result (true=END) or an intermediate result |
| 118 | * (false=CONTINUE) |
| 119 | * \param[in] invoke_id InvokeID of the request |
| 120 | */ |
| 121 | static int euse_tx_ussd_resp_7bit(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id, |
| 122 | bool final, uint8_t invoke_id, const char *text) |
| 123 | { |
| 124 | struct msgb *ss_msg; |
| 125 | |
| 126 | /* encode response; remove L3 header */ |
| 127 | ss_msg = gsm0480_gen_ussd_resp_7bit(invoke_id, text); |
| 128 | LOGP(DMAIN, LOGL_DEBUG, "Tx %s/0x%08x: USSD Result(%d, %s, '%s')\n", imsi, session_id, |
| 129 | invoke_id, final ? "END" : "CONTINUE", text); |
| 130 | OSMO_ASSERT(ss_msg); |
| 131 | return euse_tx_ss(gsupc, imsi, session_id, OSMO_GSUP_MSGT_PROC_SS_RESULT, final, ss_msg); |
| 132 | } |
| 133 | |
| 134 | static int euse_rx_proc_ss_req(struct osmo_gsup_client *gsupc, const struct osmo_gsup_message *gsup) |
| 135 | { |
| 136 | char buf[GSM0480_USSD_7BIT_STRING_LEN+1]; |
| 137 | struct ss_request req = {0}; |
| 138 | |
| 139 | if (gsup->ss_info && gsup->ss_info_len) { |
| 140 | if (gsm0480_parse_facility_ie(gsup->ss_info, gsup->ss_info_len, &req)) { |
| 141 | return euse_tx_ussd_reject(gsupc, gsup->imsi, gsup->session_id, -1, |
| 142 | GSM_0480_PROBLEM_CODE_TAG_GENERAL, |
| 143 | GSM_0480_GEN_PROB_CODE_BAD_STRUCTURE); |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | LOGP(DMAIN, LOGL_INFO, "Rx %s/0x%08x: USSD SessionState=%s, OpCode=%s, '%s'\n", gsup->imsi, |
| 148 | gsup->session_id, osmo_gsup_session_state_name(gsup->session_state), |
| 149 | gsm0480_op_code_name(req.opcode), req.ussd_text); |
| 150 | |
| 151 | /* we only handle single-request-response USSD in this demo */ |
| 152 | if (gsup->session_state != OSMO_GSUP_SESSION_STATE_BEGIN) { |
| 153 | return euse_tx_ussd_reject(gsupc, gsup->imsi, gsup->session_id, req.invoke_id, |
| 154 | GSM_0480_PROBLEM_CODE_TAG_GENERAL, |
| 155 | GSM_0480_GEN_PROB_CODE_UNRECOGNISED); |
| 156 | } |
| 157 | |
| 158 | snprintf(buf, sizeof(buf), "You sent \"%s\"", req.ussd_text); |
| 159 | return euse_tx_ussd_resp_7bit(gsupc, gsup->imsi, gsup->session_id, true, req.invoke_id, buf); |
| 160 | } |
| 161 | |
| 162 | static int gsupc_read_cb(struct osmo_gsup_client *gsupc, struct msgb *msg) |
| 163 | { |
| 164 | struct osmo_gsup_message gsup_msg = {0}; |
| 165 | int rc; |
| 166 | |
| 167 | rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup_msg); |
| 168 | if (rc < 0) { |
| 169 | LOGP(DMAIN, LOGL_ERROR, "Error decoding GSUP: %s\n", msgb_hexdump(msg)); |
| 170 | return rc; |
| 171 | } |
| 172 | DEBUGP(DMAIN, "Rx GSUP %s: %s\n", osmo_gsup_message_type_name(gsup_msg.message_type), |
| 173 | msgb_hexdump(msg)); |
| 174 | |
| 175 | switch (gsup_msg.message_type) { |
| 176 | case OSMO_GSUP_MSGT_PROC_SS_REQUEST: |
| 177 | case OSMO_GSUP_MSGT_PROC_SS_RESULT: |
| 178 | euse_rx_proc_ss_req(gsupc, &gsup_msg); |
| 179 | break; |
| 180 | case OSMO_GSUP_MSGT_PROC_SS_ERROR: |
| 181 | break; |
| 182 | default: |
| 183 | LOGP(DMAIN, LOGL_DEBUG, "Unhandled GSUP message type %s\n", |
| 184 | osmo_gsup_message_type_name(gsup_msg.message_type)); |
| 185 | break; |
| 186 | } |
| 187 | |
| 188 | msgb_free(msg); |
| 189 | return 0; |
| 190 | } |
| 191 | |
| 192 | |
| 193 | static struct log_info_cat default_categories[] = { |
| 194 | [DMAIN] = { |
| 195 | .name = "DMAIN", |
| 196 | .description = "Main Program", |
| 197 | .enabled = 1, .loglevel = LOGL_DEBUG, |
| 198 | }, |
| 199 | }; |
| 200 | |
| 201 | static const struct log_info gsup_log_info = { |
| 202 | .cat = default_categories, |
| 203 | .num_cat = ARRAY_SIZE(default_categories), |
| 204 | }; |
| 205 | |
| 206 | static void print_usage(void) |
| 207 | { |
| 208 | printf("Usage: osmo-euse-demo [hlr-ip [hlr-gsup-port]]\n"); |
| 209 | } |
| 210 | |
| 211 | int main(int argc, char **argv) |
| 212 | { |
| 213 | char *server_host = "127.0.0.1"; |
| 214 | uint16_t server_port = OSMO_GSUP_PORT; |
| 215 | void *ctx = talloc_named_const(NULL, 0, "demo-euse"); |
| 216 | |
| 217 | osmo_init_logging2(ctx, &gsup_log_info); |
| 218 | |
| 219 | printf("argc=%d\n", argc); |
| 220 | |
| 221 | if (argc > 1) { |
| 222 | if (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")) { |
| 223 | print_usage(); |
| 224 | exit(0); |
| 225 | } else |
| 226 | server_host = argv[1]; |
| 227 | } |
| 228 | if (argc > 2) |
| 229 | server_port = atoi(argv[2]); |
| 230 | |
| 231 | g_gc = osmo_gsup_client_create(ctx, "EUSE-foobar", server_host, server_port, gsupc_read_cb, NULL); |
| 232 | |
| 233 | while (1) { |
| 234 | osmo_select_main(0); |
| 235 | } |
| 236 | |
| 237 | exit(0); |
| 238 | } |
| 239 | |