view sip-out/e911.c @ 259:9f96e5b14755

sip-out: implement E911 special handling
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 15 Aug 2023 11:28:30 -0800
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/*
 * In this module we implement E911 routing, i.e., special handling
 * for calls to either the real 911 or E911 test numbers.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <syslog.h>
#include "../include/mncc.h"
#include "../include/gsm48_const.h"
#include "../include/number_db_v2.h"
#include "../libnumdb2/lookup_func.h"

e911_call_preen(msg)
	struct gsm_mncc *msg;
{
	struct owned_number_rec *nr;

	syslog(LOG_NOTICE, "E911 call attempt from %s to %s, emergency flag %d",
		msg->calling.number, msg->called.number, msg->emergency);
	refresh_number_db();
	nr = numdb_lookup_nanp(msg->calling.number+1);
	if (!nr) {
		syslog(LOG_NOTICE,
		"E911 call rejected: calling number is not in database");
		return 0;
	}
	if (nr->number_flags & NUMBER_FLAG_E911PROV) {
		syslog(LOG_NOTICE,
			"E911 call allowed: calling number has E911 flag set");
		return 1;
	}
	if (nr->usage & NUMBER_USAGE_FLAG_E911_VIA) {
		sprintf(msg->calling.number, "1%03u%03u%04u",
			nr->remap[0], nr->remap[1], nr->remap[2]);
		syslog(LOG_NOTICE, "E911 call: source number changed to %s",
			msg->calling.number);
		return 1;
	}
	syslog(LOG_NOTICE,
		"E911 call rejected: calling number is not E911-provisioned");
	return 0;
}