240 lines
7.8 KiB
C
240 lines
7.8 KiB
C
/* osmo-demo-euse: An External USSD Entity (EUSE) for demo purpose */
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/* (C) 2018 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* This program illustrates how to implement an external USSD application using
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* the existing osmocom libraries, particularly libosmocore, libosmogsm and libosmo-gsup-client.
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*
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* It will receive any MS-originated USSD message that is routed to it via the HLR, and
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* simply respond it quoted in the following string: 'You sent "foobar"' (assuming the original
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* message was 'foobar').
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*/
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <signal.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/select.h>
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#include <osmocom/core/application.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/gsm/gsup.h>
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#include <osmocom/gsm/gsm0480.h>
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#include <osmocom/gsm/protocol/gsm_04_80.h>
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#include <osmocom/gsupclient/gsup_client.h>
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#include <osmocom/hlr/logging.h>
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static struct osmo_gsup_client *g_gc;
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/*! send a SS/USSD response to a given imsi/session.
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* \param[in] gsupc GSUP client connection through which to send
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* \param[in] imsi IMSI of the subscriber
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* \param[in] session_id Unique identifier of SS session for which this response is
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* \param[in] gsup_msg_type GSUP message type (OSMO_GSUP_MSGT_PROC_SS_{REQUEST,RESULT,ERROR})
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* \param[in] final Is this the final result (true=END) or an intermediate result (false=CONTINUE)
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* \param[in] msg Optional binary/BER encoded SS date (for FACILITY IE). Can be NULL. Freed in
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* this function call.
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*/
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static int euse_tx_ss(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id,
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enum osmo_gsup_message_type gsup_msg_type, bool final, struct msgb *ss_msg)
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{
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struct osmo_gsup_message resp = {0};
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struct msgb *resp_msg;
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switch (gsup_msg_type) {
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case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
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case OSMO_GSUP_MSGT_PROC_SS_RESULT:
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case OSMO_GSUP_MSGT_PROC_SS_ERROR:
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break;
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default:
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msgb_free(ss_msg);
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return -EINVAL;
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}
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resp.message_type = gsup_msg_type;
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OSMO_STRLCPY_ARRAY(resp.imsi, imsi);
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if (final)
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resp.session_state = OSMO_GSUP_SESSION_STATE_END;
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else
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resp.session_state = OSMO_GSUP_SESSION_STATE_CONTINUE;
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resp.session_id = session_id;
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if (ss_msg) {
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resp.ss_info = msgb_data(ss_msg);
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resp.ss_info_len = msgb_length(ss_msg);
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}
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resp_msg = gsm0480_msgb_alloc_name(__func__);
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OSMO_ASSERT(resp_msg);
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osmo_gsup_encode(resp_msg, &resp);
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msgb_free(ss_msg);
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return osmo_gsup_client_send(gsupc, resp_msg);
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}
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/*! send a SS/USSD reject to a given IMSI/session.
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* \param[in] gsupc GSUP client connection through which to send
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* \param[in] imsi IMSI of the subscriber
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* \param[in] session_id Unique identifier of SS session for which this response is
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* \param[in] invoke_id InvokeID of the request
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* \param[in] problem_tag Problem code tag (table 3.13)
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* \param[in] problem_code Problem code (table 3.14-3.17)
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*/
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static int euse_tx_ussd_reject(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id,
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int invoke_id, uint8_t problem_tag, uint8_t problem_code)
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{
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struct msgb *msg = gsm0480_gen_reject(invoke_id, problem_tag, problem_code);
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LOGP(DMAIN, LOGL_NOTICE, "Tx %s/0x%08x: Reject(%d, 0x%02x, 0x%02x)\n", imsi, session_id,
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invoke_id, problem_tag, problem_code);
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OSMO_ASSERT(msg);
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return euse_tx_ss(gsupc, imsi, session_id, OSMO_GSUP_MSGT_PROC_SS_RESULT, true, msg);
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}
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/*! send a SS/USSD response in 7-bit GSM default alphabet o a given imsi/session.
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* \param[in] gsupc GSUP client connection through which to send
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* \param[in] imsi IMSI of the subscriber
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* \param[in] session_id Unique identifier of SS session for which this response is
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* \param[in] final Is this the final result (true=END) or an intermediate result
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* (false=CONTINUE)
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* \param[in] invoke_id InvokeID of the request
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*/
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static int euse_tx_ussd_resp_7bit(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id,
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bool final, uint8_t invoke_id, const char *text)
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{
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struct msgb *ss_msg;
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/* encode response; remove L3 header */
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ss_msg = gsm0480_gen_ussd_resp_7bit(invoke_id, text);
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LOGP(DMAIN, LOGL_DEBUG, "Tx %s/0x%08x: USSD Result(%d, %s, '%s')\n", imsi, session_id,
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invoke_id, final ? "END" : "CONTINUE", text);
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OSMO_ASSERT(ss_msg);
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return euse_tx_ss(gsupc, imsi, session_id, OSMO_GSUP_MSGT_PROC_SS_RESULT, final, ss_msg);
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}
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static int euse_rx_proc_ss_req(struct osmo_gsup_client *gsupc, const struct osmo_gsup_message *gsup)
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{
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char buf[GSM0480_USSD_7BIT_STRING_LEN+1];
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struct ss_request req = {0};
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if (gsup->ss_info && gsup->ss_info_len) {
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if (gsm0480_parse_facility_ie(gsup->ss_info, gsup->ss_info_len, &req)) {
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return euse_tx_ussd_reject(gsupc, gsup->imsi, gsup->session_id, -1,
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GSM_0480_PROBLEM_CODE_TAG_GENERAL,
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GSM_0480_GEN_PROB_CODE_BAD_STRUCTURE);
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}
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}
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LOGP(DMAIN, LOGL_INFO, "Rx %s/0x%08x: USSD SessionState=%s, OpCode=%s, '%s'\n", gsup->imsi,
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gsup->session_id, osmo_gsup_session_state_name(gsup->session_state),
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gsm0480_op_code_name(req.opcode), req.ussd_text);
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/* we only handle single-request-response USSD in this demo */
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if (gsup->session_state != OSMO_GSUP_SESSION_STATE_BEGIN) {
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return euse_tx_ussd_reject(gsupc, gsup->imsi, gsup->session_id, req.invoke_id,
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GSM_0480_PROBLEM_CODE_TAG_GENERAL,
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GSM_0480_GEN_PROB_CODE_UNRECOGNISED);
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}
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snprintf(buf, sizeof(buf), "You sent \"%s\"", req.ussd_text);
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return euse_tx_ussd_resp_7bit(gsupc, gsup->imsi, gsup->session_id, true, req.invoke_id, buf);
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}
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static int gsupc_read_cb(struct osmo_gsup_client *gsupc, struct msgb *msg)
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{
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struct osmo_gsup_message gsup_msg = {0};
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int rc;
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rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup_msg);
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if (rc < 0) {
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LOGP(DMAIN, LOGL_ERROR, "Error decoding GSUP: %s\n", msgb_hexdump(msg));
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return rc;
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}
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DEBUGP(DMAIN, "Rx GSUP %s: %s\n", osmo_gsup_message_type_name(gsup_msg.message_type),
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msgb_hexdump(msg));
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switch (gsup_msg.message_type) {
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case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
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case OSMO_GSUP_MSGT_PROC_SS_RESULT:
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euse_rx_proc_ss_req(gsupc, &gsup_msg);
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break;
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case OSMO_GSUP_MSGT_PROC_SS_ERROR:
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break;
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default:
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LOGP(DMAIN, LOGL_DEBUG, "Unhandled GSUP message type %s\n",
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osmo_gsup_message_type_name(gsup_msg.message_type));
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break;
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}
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msgb_free(msg);
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return 0;
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}
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static struct log_info_cat default_categories[] = {
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[DMAIN] = {
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.name = "DMAIN",
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.description = "Main Program",
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.enabled = 1, .loglevel = LOGL_DEBUG,
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},
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};
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static const struct log_info gsup_log_info = {
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.cat = default_categories,
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.num_cat = ARRAY_SIZE(default_categories),
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};
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static void print_usage(void)
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{
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printf("Usage: osmo-euse-demo [hlr-ip [hlr-gsup-port]]\n");
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}
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int main(int argc, char **argv)
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{
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char *server_host = "127.0.0.1";
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uint16_t server_port = OSMO_GSUP_PORT;
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void *ctx = talloc_named_const(NULL, 0, "demo-euse");
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osmo_init_logging2(ctx, &gsup_log_info);
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printf("argc=%d\n", argc);
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if (argc > 1) {
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if (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")) {
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print_usage();
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exit(0);
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} else
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server_host = argv[1];
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}
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if (argc > 2)
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server_port = atoi(argv[2]);
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g_gc = osmo_gsup_client_create(ctx, "EUSE-foobar", server_host, server_port, gsupc_read_cb, NULL);
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while (1) {
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osmo_select_main(0);
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}
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exit(0);
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}
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