pjsip/src/test-pjsip/dns_test.c - pjproject - Gitiles

 /* $Id$ */
 /*
  * Copyright (C) 2003-2007 Benny Prijono <benny@prijono.org>
  *
  * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 #include "test.h"
 #include <pjsip.h>
 #include <pjlib.h>
 #include <pjlib-util.h>

 /* For logging purpose. */
 #define THIS_FILE   "dns_test.c"

 struct result
 {
     pj_status_t		    status;
     pjsip_server_addresses  servers;
 };


 static void cb(pj_status_t status,
 	       void *token,
 	       const struct pjsip_server_addresses *addr)
 {
     struct result *result = token;

     result->status = status;
     if (status == PJ_SUCCESS)
 	pj_memcpy(&result->servers, addr, sizeof(*addr));
 }


 static void add_dns_entries(pj_dns_resolver *resv)
 {
     /* Inject DNS SRV entry */
     pj_dns_parsed_packet pkt;
     pj_dns_parsed_rr ans[4];
     pj_dns_parsed_rr ar[5];
     pj_str_t tmp;
     unsigned i;

     /*
      * This is answer to SRV query to "example.com" domain, and
      * the answer contains full reference to the A records of
      * the server. The full DNS records is :

      _sip._udp.example.com 3600 IN SRV 0 0  5060 sip01.example.com.
      _sip._udp.example.com 3600 IN SRV 0 20 5060 sip02.example.com.
      _sip._udp.example.com 3600 IN SRV 0 10 5060 sip03.example.com.
      _sip._udp.example.com 3600 IN SRV 1 0  5060 sip04.example.com.

      sip01.example.com. 3600 IN A       1.1.1.1
      sip02.example.com. 3600 IN A       2.2.2.2
      sip03.example.com. 3600 IN A       3.3.3.3
      sip04.example.com. 3600 IN A       4.4.4.4

      ; Additionally, add A record for "example.com"
      example.com.	3600 IN A       5.5.5.5

      */
     pj_bzero(&pkt, sizeof(pkt));
     pj_bzero(ans, sizeof(ans));
     pj_bzero(ar, sizeof(ar));

     pkt.hdr.flags = PJ_DNS_SET_QR(1);
     pkt.hdr.anscount = PJ_ARRAY_SIZE(ans);
     pkt.hdr.arcount = 0;
     pkt.ans = ans;
     pkt.arr = ar;

     ans[0].name = pj_str("_sip._udp.example.com");
     ans[0].type = PJ_DNS_TYPE_SRV;
     ans[0].dnsclass = PJ_DNS_CLASS_IN;
     ans[0].ttl = 3600;
     ans[0].rdata.srv.prio = 0;
     ans[0].rdata.srv.weight = 0;
     ans[0].rdata.srv.port = 5060;
     ans[0].rdata.srv.target = pj_str("sip01.example.com");

     ans[1].name = pj_str("_sip._udp.example.com");
     ans[1].type = PJ_DNS_TYPE_SRV;
     ans[1].dnsclass = PJ_DNS_CLASS_IN;
     ans[1].ttl = 3600;
     ans[1].rdata.srv.prio = 0;
     ans[1].rdata.srv.weight = 20;
     ans[1].rdata.srv.port = 5060;
     ans[1].rdata.srv.target = pj_str("sip02.example.com");

     ans[2].name = pj_str("_sip._udp.example.com");
     ans[2].type = PJ_DNS_TYPE_SRV;
     ans[2].dnsclass = PJ_DNS_CLASS_IN;
     ans[2].ttl = 3600;
     ans[2].rdata.srv.prio = 0;
     ans[2].rdata.srv.weight = 10;
     ans[2].rdata.srv.port = 5060;
     ans[2].rdata.srv.target = pj_str("sip03.example.com");

     ans[3].name = pj_str("_sip._udp.example.com");
     ans[3].type = PJ_DNS_TYPE_SRV;
     ans[3].dnsclass = PJ_DNS_CLASS_IN;
     ans[3].ttl = 3600;
     ans[3].rdata.srv.prio = 1;
     ans[3].rdata.srv.weight = 0;
     ans[3].rdata.srv.port = 5060;
     ans[3].rdata.srv.target = pj_str("sip04.example.com");

     pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);

     ar[0].name = pj_str("sip01.example.com");
     ar[0].type = PJ_DNS_TYPE_A;
     ar[0].dnsclass = PJ_DNS_CLASS_IN;
     ar[0].ttl = 3600;
     ar[0].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "1.1.1.1"));

     ar[1].name = pj_str("sip02.example.com");
     ar[1].type = PJ_DNS_TYPE_A;
     ar[1].dnsclass = PJ_DNS_CLASS_IN;
     ar[1].ttl = 3600;
     ar[1].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "2.2.2.2"));

     ar[2].name = pj_str("sip03.example.com");
     ar[2].type = PJ_DNS_TYPE_A;
     ar[2].dnsclass = PJ_DNS_CLASS_IN;
     ar[2].ttl = 3600;
     ar[2].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "3.3.3.3"));

     ar[3].name = pj_str("sip04.example.com");
     ar[3].type = PJ_DNS_TYPE_A;
     ar[3].dnsclass = PJ_DNS_CLASS_IN;
     ar[3].ttl = 3600;
     ar[3].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "4.4.4.4"));

     ar[4].name = pj_str("example.com");
     ar[4].type = PJ_DNS_TYPE_A;
     ar[4].dnsclass = PJ_DNS_CLASS_IN;
     ar[4].ttl = 3600;
     ar[4].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "5.5.5.5"));

     /*
      * Create individual A records for all hosts in "example.com" domain.
      */
     for (i=0; i<PJ_ARRAY_SIZE(ar); ++i) {
 	pj_bzero(&pkt, sizeof(pkt));
 	pkt.hdr.anscount = 1;
 	pkt.hdr.flags = PJ_DNS_SET_QR(1);
 	pkt.ans = &ar[i];

 	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);
     }

     /*
      * Simulate DNS error response by creating these answers.
      * Sample of invalid SRV records: _sip._udp.sip01.example.com.
      */
     for (i=0; i<PJ_ARRAY_SIZE(ans); ++i) {
 	pj_dns_parsed_query q;
 	char buf[128];
 	char *services[] = { "_sip._udp.", "_sip._tcp.", "_sips._tcp."};
 	unsigned j;

 	for (j=0; j<PJ_ARRAY_SIZE(services); ++j) {
 	    q.dnsclass = PJ_DNS_CLASS_IN;
 	    q.type = PJ_DNS_TYPE_SRV;

 	    q.name.ptr = buf;
 	    pj_bzero(buf, sizeof(buf));
 	    pj_strcpy2(&q.name, services[j]);
 	    pj_strcat(&q.name, &ans[i].rdata.srv.target);

 	    pj_bzero(&pkt, sizeof(pkt));
 	    pkt.hdr.qdcount = 1;
 	    pkt.hdr.flags = PJ_DNS_SET_QR(1) |
 			    PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NXDOMAIN);
 	    pkt.q = &q;

 	    pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);
 	}
     }


     /*
      * ANOTHER DOMAIN.
      *
      * This time we let SRV and A get answered in different DNS
      * query.
      */

     /* The "domain.com" DNS records (note the different the port):

 	_sip._tcp.domain.com 3600 IN SRV 1 0 50060 sip06.domain.com.
 	_sip._tcp.domain.com 3600 IN SRV 2 0 50060 sip07.domain.com.

 	sip06.domain.com. 3600 IN A       6.6.6.6
 	sip07.domain.com. 3600 IN A       7.7.7.7
      */

     pj_bzero(&pkt, sizeof(pkt));
     pj_bzero(&ans, sizeof(ans));
     pkt.hdr.flags = PJ_DNS_SET_QR(1);
     pkt.hdr.anscount = 2;
     pkt.ans = ans;

     /* Add the SRV records, with reverse priority (to test that sorting
      * works.
      */
     ans[0].name = pj_str("_sip._tcp.domain.com");
     ans[0].type = PJ_DNS_TYPE_SRV;
     ans[0].dnsclass = PJ_DNS_CLASS_IN;
     ans[0].ttl = 3600;
     ans[0].rdata.srv.prio = 2;
     ans[0].rdata.srv.weight = 0;
     ans[0].rdata.srv.port = 50060;
     ans[0].rdata.srv.target = pj_str("SIP07.DOMAIN.COM");

     ans[1].name = pj_str("_sip._tcp.domain.com");
     ans[1].type = PJ_DNS_TYPE_SRV;
     ans[1].dnsclass = PJ_DNS_CLASS_IN;
     ans[1].ttl = 3600;
     ans[1].rdata.srv.prio = 1;
     ans[1].rdata.srv.weight = 0;
     ans[1].rdata.srv.port = 50060;
     ans[1].rdata.srv.target = pj_str("SIP06.DOMAIN.COM");

     pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);

     /* From herein there is only one answer */
     pkt.hdr.anscount = 1;

     /* Add a single SRV for UDP */
     ans[0].name = pj_str("_sip._udp.domain.com");
     ans[0].type = PJ_DNS_TYPE_SRV;
     ans[0].dnsclass = PJ_DNS_CLASS_IN;
     ans[0].ttl = 3600;
     ans[0].rdata.srv.prio = 0;
     ans[0].rdata.srv.weight = 0;
     ans[0].rdata.srv.port = 50060;
     ans[0].rdata.srv.target = pj_str("SIP06.DOMAIN.COM");

     pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);


     /* Add the A record for sip06.domain.com */
     ans[0].name = pj_str("sip06.domain.com");
     ans[0].type = PJ_DNS_TYPE_A;
     ans[0].dnsclass = PJ_DNS_CLASS_IN;
     ans[0].ttl = 3600;
     ans[0].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "6.6.6.6"));

     pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);

     /* Add the A record for sip07.domain.com */
     ans[0].name = pj_str("sip07.domain.com");
     ans[0].type = PJ_DNS_TYPE_A;
     ans[0].dnsclass = PJ_DNS_CLASS_IN;
     ans[0].ttl = 3600;
     ans[0].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "7.7.7.7"));

     pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);
 }


 /*
  * Perform server resolution where the results are expected to
  * come in strict order.
  */
 static int test_resolve(const char *title,
 			pj_pool_t *pool,
 			pjsip_transport_type_e type,
 			char *name,
 			int port,
 			pjsip_server_addresses *ref)
 {
     pjsip_host_info dest;
     struct result result;

     PJ_LOG(3,(THIS_FILE, " test_resolve(): %s", title));

     dest.type = type;
     dest.flag = pjsip_transport_get_flag_from_type(type);
     dest.addr.host = pj_str(name);
     dest.addr.port = port;

     result.status = 0x12345678;

     pjsip_endpt_resolve(endpt, pool, &dest, &result, &cb);

     while (result.status == 0x12345678) {
 	int i = 0;
 	pj_time_val timeout = { 1, 0 };
 	pjsip_endpt_handle_events(endpt, &timeout);
 	if (i == 1)
 	    pj_dns_resolver_dump(pjsip_endpt_get_resolver(endpt), PJ_TRUE);
     }

     if (result.status != PJ_SUCCESS) {
 	app_perror("  pjsip_endpt_resolve() error", result.status);
 	return result.status;
     }

     if (ref) {
 	unsigned i;

 	if (ref->count != result.servers.count) {
 	    PJ_LOG(3,(THIS_FILE, "  test_resolve() error 10: result count mismatch"));
 	    return 10;
 	}

 	for (i=0; i<ref->count; ++i) {
 	    pj_sockaddr_in *ra = (pj_sockaddr_in *)&ref->entry[i].addr;
 	    pj_sockaddr_in *rb = (pj_sockaddr_in *)&result.servers.entry[i].addr;

 	    if (ra->sin_addr.s_addr != rb->sin_addr.s_addr) {
 		PJ_LOG(3,(THIS_FILE, "  test_resolve() error 20: IP address mismatch"));
 		return 20;
 	    }
 	    if (ra->sin_port != rb->sin_port) {
 		PJ_LOG(3,(THIS_FILE, "  test_resolve() error 30: port mismatch"));
 		return 30;
 	    }
 	    if (ref->entry[i].addr_len != result.servers.entry[i].addr_len) {
 		PJ_LOG(3,(THIS_FILE, "  test_resolve() error 40: addr_len mismatch"));
 		return 40;
 	    }
 	    if (ref->entry[i].type != result.servers.entry[i].type) {
 		PJ_LOG(3,(THIS_FILE, "  test_resolve() error 50: transport type mismatch"));
 		return 50;
 	    }
 	}
     }

     return PJ_SUCCESS;
 }

 /*
  * Perform round-robin/load balance test.
  */
 static int round_robin_test(pj_pool_t *pool)
 {
     enum { COUNT = 400, PCT_ALLOWANCE = 5 };
     unsigned i;
     struct server_hit
     {
 	char *ip_addr;
 	unsigned percent;
 	unsigned hits;
     } server_hit[] =
     {
 	{ "1.1.1.1", 3,  0 },
 	{ "2.2.2.2", 65, 0 },
 	{ "3.3.3.3", 32, 0 },
 	{ "4.4.4.4", 0,  0 }
     };

     PJ_LOG(3,(THIS_FILE, " Performing round-robin/load-balance test.."));

     /* Do multiple resolve request to "example.com".
      * The resolver should select the server based on the weight proportion
      * the the servers in the SRV entry.
      */
     for (i=0; i<COUNT; ++i) {
 	pjsip_host_info dest;
 	struct result result;
 	unsigned j;

 	dest.type = PJSIP_TRANSPORT_UDP;
 	dest.flag = pjsip_transport_get_flag_from_type(PJSIP_TRANSPORT_UDP);
 	dest.addr.host = pj_str("example.com");
 	dest.addr.port = 0;

 	result.status = 0x12345678;

 	pjsip_endpt_resolve(endpt, pool, &dest, &result, &cb);

 	while (result.status == 0x12345678) {
 	    int i = 0;
 	    pj_time_val timeout = { 1, 0 };
 	    pjsip_endpt_handle_events(endpt, &timeout);
 	    if (i == 1)
 		pj_dns_resolver_dump(pjsip_endpt_get_resolver(endpt), PJ_TRUE);
 	}

 	/* Find which server was "hit" */
 	for (j=0; j<PJ_ARRAY_SIZE(server_hit); ++j) {
 	    pj_str_t tmp;
 	    pj_in_addr a1;
 	    pj_sockaddr_in *a2;

 	    tmp = pj_str(server_hit[j].ip_addr);
 	    a1 = pj_inet_addr(&tmp);
 	    a2 = (pj_sockaddr_in*) &result.servers.entry[0].addr;

 	    if (a1.s_addr == a2->sin_addr.s_addr) {
 		server_hit[j].hits++;
 		break;
 	    }
 	}

 	if (j == PJ_ARRAY_SIZE(server_hit)) {
 	    PJ_LOG(1,(THIS_FILE, "..round_robin_test() error 10: returned address mismatch"));
 	    return 10;
 	}
     }

     /* Print the actual hit rate */
     for (i=0; i<PJ_ARRAY_SIZE(server_hit); ++i) {
 	PJ_LOG(3,(THIS_FILE, " ..Server %s: weight=%d%%, hit %d%% times",
 		  server_hit[i].ip_addr, server_hit[i].percent,
 		  (server_hit[i].hits * 100) / COUNT));
     }

     /* Compare the actual hit with the weight proportion */
     for (i=0; i<PJ_ARRAY_SIZE(server_hit); ++i) {
 	int actual_pct = (server_hit[i].hits * 100) / COUNT;

 	if (actual_pct + PCT_ALLOWANCE < (int)server_hit[i].percent ||
 	    actual_pct - PCT_ALLOWANCE > (int)server_hit[i].percent)
 	{
 	    PJ_LOG(1,(THIS_FILE,
 		      "..round_robin_test() error 20: "
 		      "hit rate difference for server %s (%d%%) is more than "
 		      "tolerable allowance (%d%%)",
 		      server_hit[i].ip_addr,
 		      actual_pct - server_hit[i].percent,
 		      PCT_ALLOWANCE));
 	    return 20;
 	}
     }

     PJ_LOG(3,(THIS_FILE,
 	      " Load balance test success, hit-rate is "
 	      "within %d%% allowance", PCT_ALLOWANCE));
     return PJ_SUCCESS;
 }


 #define C(expr)	    status = expr; \
 		    if (status != PJ_SUCCESS) app_perror(THIS_FILE, "Error", status);

 static void add_ref(pjsip_server_addresses *r,
 		    pjsip_transport_type_e type,
 		    char *addr,
 		    int port)
 {
     pj_sockaddr_in *a;
     pj_str_t tmp;

     r->entry[r->count].type = type;
     r->entry[r->count].priority = 0;
     r->entry[r->count].weight = 0;
     r->entry[r->count].addr_len = sizeof(pj_sockaddr_in);

     a = (pj_sockaddr_in *)&r->entry[r->count].addr;
     a->sin_family = PJ_AF_INET;
     tmp = pj_str(addr);
     a->sin_addr = pj_inet_addr(&tmp);
     a->sin_port = pj_htons((pj_uint16_t)port);

     r->count++;
 }

 static void create_ref(pjsip_server_addresses *r,
 		       pjsip_transport_type_e type,
 		       char *addr,
 		       int port)
 {
     r->count = 0;
     add_ref(r, type, addr, port);
 }


 /*
  * Main test entry.
  */
 int resolve_test(void)
 {
     pj_pool_t *pool;
     pj_dns_resolver *resv;
     pj_str_t nameserver;
     pj_uint16_t port = 5353;
     pj_status_t status;

     pool = pjsip_endpt_create_pool(endpt, NULL, 4000, 4000);

     status = pjsip_endpt_create_resolver(endpt, &resv);

     nameserver = pj_str("192.168.0.106");
     pj_dns_resolver_set_ns(resv, 1, &nameserver, &port);
     pjsip_endpt_set_resolver(endpt, resv);

     add_dns_entries(resv);

     /* These all should be resolved as IP addresses (DNS A query) */
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_UDP, "1.1.1.1", 5060);
 	status = test_resolve("IP address without transport and port", pool, PJSIP_TRANSPORT_UNSPECIFIED, "1.1.1.1", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -100;
     }
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_UDP, "1.1.1.1", 5060);
 	status = test_resolve("IP address with explicit port", pool, PJSIP_TRANSPORT_UNSPECIFIED, "1.1.1.1", 5060, &ref);
 	if (status != PJ_SUCCESS)
 	    return -110;
     }
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_TCP, "1.1.1.1", 5060);
 	status = test_resolve("IP address without port (TCP)", pool, PJSIP_TRANSPORT_TCP,"1.1.1.1", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -120;
     }
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_TLS, "1.1.1.1", 5061);
 	status = test_resolve("IP address without port (TLS)", pool, PJSIP_TRANSPORT_TLS, "1.1.1.1", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -130;
     }

     /* This should be resolved as DNS A record (because port is present) */
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_UDP, "5.5.5.5", 5060);
 	status = test_resolve("domain name with port should resolve to A record", pool, PJSIP_TRANSPORT_UNSPECIFIED, "example.com", 5060, &ref);
 	if (status != PJ_SUCCESS)
 	    return -140;
     }

     /* This will fail to be resolved as SRV, resolver should fallback to
      * resolving to A record.
      */
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_UDP, "2.2.2.2", 5060);
 	status = test_resolve("failure with SRV fallback to A record", pool, PJSIP_TRANSPORT_UNSPECIFIED, "sip02.example.com", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -150;
     }

     /* Same as above, but explicitly for TLS. */
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_TLS, "2.2.2.2", 5061);
 	status = test_resolve("failure with SRV fallback to A record (for TLS)", pool, PJSIP_TRANSPORT_TLS, "sip02.example.com", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -150;
     }

     /* Standard DNS SRV followed by A recolution */
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_UDP, "6.6.6.6", 50060);
 	status = test_resolve("standard SRV resolution", pool, PJSIP_TRANSPORT_UNSPECIFIED, "domain.com", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -155;
     }

     /* Standard DNS SRV followed by A recolution (explicit transport) */
     {
 	pjsip_server_addresses ref;
 	create_ref(&ref, PJSIP_TRANSPORT_TCP, "6.6.6.6", 50060);
 	add_ref(&ref, PJSIP_TRANSPORT_TCP, "7.7.7.7", 50060);
 	status = test_resolve("standard SRV resolution with explicit transport (TCP)", pool, PJSIP_TRANSPORT_TCP, "domain.com", 0, &ref);
 	if (status != PJ_SUCCESS)
 	    return -160;
     }


     /* Round robin/load balance test */
     if (round_robin_test(pool) != 0)
 	return -170;

     /* Timeout test */
     {
 	status = test_resolve("timeout test", pool, PJSIP_TRANSPORT_UNSPECIFIED, "an.invalid.address", 0, NULL);
 	if (status == PJ_SUCCESS)
 	    return -150;
     }

     return 0;
 }
	/* $Id$ */
	/*
	* Copyright (C) 2003-2007 Benny Prijono <benny@prijono.org>
	*
	* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/
	#include "test.h"
	#include <pjsip.h>
	#include <pjlib.h>
	#include <pjlib-util.h>

	/* For logging purpose. */
	#define THIS_FILE "dns_test.c"

	struct result
	{
	pj_status_t status;
	pjsip_server_addresses servers;
	};


	static void cb(pj_status_t status,
	void *token,
	const struct pjsip_server_addresses *addr)
	{
	struct result *result = token;

	result->status = status;
	if (status == PJ_SUCCESS)
	pj_memcpy(&result->servers, addr, sizeof(*addr));
	}


	static void add_dns_entries(pj_dns_resolver *resv)
	{
	/* Inject DNS SRV entry */
	pj_dns_parsed_packet pkt;
	pj_dns_parsed_rr ans[4];
	pj_dns_parsed_rr ar[5];
	pj_str_t tmp;
	unsigned i;

	/*
	* This is answer to SRV query to "example.com" domain, and
	* the answer contains full reference to the A records of
	* the server. The full DNS records is :

	_sip._udp.example.com 3600 IN SRV 0 0 5060 sip01.example.com.
	_sip._udp.example.com 3600 IN SRV 0 20 5060 sip02.example.com.
	_sip._udp.example.com 3600 IN SRV 0 10 5060 sip03.example.com.
	_sip._udp.example.com 3600 IN SRV 1 0 5060 sip04.example.com.

	sip01.example.com. 3600 IN A 1.1.1.1
	sip02.example.com. 3600 IN A 2.2.2.2
	sip03.example.com. 3600 IN A 3.3.3.3
	sip04.example.com. 3600 IN A 4.4.4.4

	; Additionally, add A record for "example.com"
	example.com. 3600 IN A 5.5.5.5

	*/
	pj_bzero(&pkt, sizeof(pkt));
	pj_bzero(ans, sizeof(ans));
	pj_bzero(ar, sizeof(ar));

	pkt.hdr.flags = PJ_DNS_SET_QR(1);
	pkt.hdr.anscount = PJ_ARRAY_SIZE(ans);
	pkt.hdr.arcount = 0;
	pkt.ans = ans;
	pkt.arr = ar;

	ans[0].name = pj_str("_sip._udp.example.com");
	ans[0].type = PJ_DNS_TYPE_SRV;
	ans[0].dnsclass = PJ_DNS_CLASS_IN;
	ans[0].ttl = 3600;
	ans[0].rdata.srv.prio = 0;
	ans[0].rdata.srv.weight = 0;
	ans[0].rdata.srv.port = 5060;
	ans[0].rdata.srv.target = pj_str("sip01.example.com");

	ans[1].name = pj_str("_sip._udp.example.com");
	ans[1].type = PJ_DNS_TYPE_SRV;
	ans[1].dnsclass = PJ_DNS_CLASS_IN;
	ans[1].ttl = 3600;
	ans[1].rdata.srv.prio = 0;
	ans[1].rdata.srv.weight = 20;
	ans[1].rdata.srv.port = 5060;
	ans[1].rdata.srv.target = pj_str("sip02.example.com");

	ans[2].name = pj_str("_sip._udp.example.com");
	ans[2].type = PJ_DNS_TYPE_SRV;
	ans[2].dnsclass = PJ_DNS_CLASS_IN;
	ans[2].ttl = 3600;
	ans[2].rdata.srv.prio = 0;
	ans[2].rdata.srv.weight = 10;
	ans[2].rdata.srv.port = 5060;
	ans[2].rdata.srv.target = pj_str("sip03.example.com");

	ans[3].name = pj_str("_sip._udp.example.com");
	ans[3].type = PJ_DNS_TYPE_SRV;
	ans[3].dnsclass = PJ_DNS_CLASS_IN;
	ans[3].ttl = 3600;
	ans[3].rdata.srv.prio = 1;
	ans[3].rdata.srv.weight = 0;
	ans[3].rdata.srv.port = 5060;
	ans[3].rdata.srv.target = pj_str("sip04.example.com");

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);

	ar[0].name = pj_str("sip01.example.com");
	ar[0].type = PJ_DNS_TYPE_A;
	ar[0].dnsclass = PJ_DNS_CLASS_IN;
	ar[0].ttl = 3600;
	ar[0].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "1.1.1.1"));

	ar[1].name = pj_str("sip02.example.com");
	ar[1].type = PJ_DNS_TYPE_A;
	ar[1].dnsclass = PJ_DNS_CLASS_IN;
	ar[1].ttl = 3600;
	ar[1].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "2.2.2.2"));

	ar[2].name = pj_str("sip03.example.com");
	ar[2].type = PJ_DNS_TYPE_A;
	ar[2].dnsclass = PJ_DNS_CLASS_IN;
	ar[2].ttl = 3600;
	ar[2].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "3.3.3.3"));

	ar[3].name = pj_str("sip04.example.com");
	ar[3].type = PJ_DNS_TYPE_A;
	ar[3].dnsclass = PJ_DNS_CLASS_IN;
	ar[3].ttl = 3600;
	ar[3].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "4.4.4.4"));

	ar[4].name = pj_str("example.com");
	ar[4].type = PJ_DNS_TYPE_A;
	ar[4].dnsclass = PJ_DNS_CLASS_IN;
	ar[4].ttl = 3600;
	ar[4].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "5.5.5.5"));

	/*
	* Create individual A records for all hosts in "example.com" domain.
	*/
	for (i=0; i<PJ_ARRAY_SIZE(ar); ++i) {
	pj_bzero(&pkt, sizeof(pkt));
	pkt.hdr.anscount = 1;
	pkt.hdr.flags = PJ_DNS_SET_QR(1);
	pkt.ans = &ar[i];

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);
	}

	/*
	* Simulate DNS error response by creating these answers.
	* Sample of invalid SRV records: _sip._udp.sip01.example.com.
	*/
	for (i=0; i<PJ_ARRAY_SIZE(ans); ++i) {
	pj_dns_parsed_query q;
	char buf[128];
	char *services[] = { "_sip._udp.", "_sip._tcp.", "_sips._tcp."};
	unsigned j;

	for (j=0; j<PJ_ARRAY_SIZE(services); ++j) {
	q.dnsclass = PJ_DNS_CLASS_IN;
	q.type = PJ_DNS_TYPE_SRV;

	q.name.ptr = buf;
	pj_bzero(buf, sizeof(buf));
	pj_strcpy2(&q.name, services[j]);
	pj_strcat(&q.name, &ans[i].rdata.srv.target);

	pj_bzero(&pkt, sizeof(pkt));
	pkt.hdr.qdcount = 1;
	pkt.hdr.flags = PJ_DNS_SET_QR(1) \|
	PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NXDOMAIN);
	pkt.q = &q;

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);
	}
	}


	/*
	* ANOTHER DOMAIN.
	*
	* This time we let SRV and A get answered in different DNS
	* query.
	*/

	/* The "domain.com" DNS records (note the different the port):

	_sip._tcp.domain.com 3600 IN SRV 1 0 50060 sip06.domain.com.
	_sip._tcp.domain.com 3600 IN SRV 2 0 50060 sip07.domain.com.

	sip06.domain.com. 3600 IN A 6.6.6.6
	sip07.domain.com. 3600 IN A 7.7.7.7
	*/

	pj_bzero(&pkt, sizeof(pkt));
	pj_bzero(&ans, sizeof(ans));
	pkt.hdr.flags = PJ_DNS_SET_QR(1);
	pkt.hdr.anscount = 2;
	pkt.ans = ans;

	/* Add the SRV records, with reverse priority (to test that sorting
	* works.
	*/
	ans[0].name = pj_str("_sip._tcp.domain.com");
	ans[0].type = PJ_DNS_TYPE_SRV;
	ans[0].dnsclass = PJ_DNS_CLASS_IN;
	ans[0].ttl = 3600;
	ans[0].rdata.srv.prio = 2;
	ans[0].rdata.srv.weight = 0;
	ans[0].rdata.srv.port = 50060;
	ans[0].rdata.srv.target = pj_str("SIP07.DOMAIN.COM");

	ans[1].name = pj_str("_sip._tcp.domain.com");
	ans[1].type = PJ_DNS_TYPE_SRV;
	ans[1].dnsclass = PJ_DNS_CLASS_IN;
	ans[1].ttl = 3600;
	ans[1].rdata.srv.prio = 1;
	ans[1].rdata.srv.weight = 0;
	ans[1].rdata.srv.port = 50060;
	ans[1].rdata.srv.target = pj_str("SIP06.DOMAIN.COM");

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);

	/* From herein there is only one answer */
	pkt.hdr.anscount = 1;

	/* Add a single SRV for UDP */
	ans[0].name = pj_str("_sip._udp.domain.com");
	ans[0].type = PJ_DNS_TYPE_SRV;
	ans[0].dnsclass = PJ_DNS_CLASS_IN;
	ans[0].ttl = 3600;
	ans[0].rdata.srv.prio = 0;
	ans[0].rdata.srv.weight = 0;
	ans[0].rdata.srv.port = 50060;
	ans[0].rdata.srv.target = pj_str("SIP06.DOMAIN.COM");

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);


	/* Add the A record for sip06.domain.com */
	ans[0].name = pj_str("sip06.domain.com");
	ans[0].type = PJ_DNS_TYPE_A;
	ans[0].dnsclass = PJ_DNS_CLASS_IN;
	ans[0].ttl = 3600;
	ans[0].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "6.6.6.6"));

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);

	/* Add the A record for sip07.domain.com */
	ans[0].name = pj_str("sip07.domain.com");
	ans[0].type = PJ_DNS_TYPE_A;
	ans[0].dnsclass = PJ_DNS_CLASS_IN;
	ans[0].ttl = 3600;
	ans[0].rdata.a.ip_addr = pj_inet_addr(pj_cstr(&tmp, "7.7.7.7"));

	pj_dns_resolver_add_entry( resv, &pkt, PJ_FALSE);
	}


	/*
	* Perform server resolution where the results are expected to
	* come in strict order.
	*/
	static int test_resolve(const char *title,
	pj_pool_t *pool,
	pjsip_transport_type_e type,
	char *name,
	int port,
	pjsip_server_addresses *ref)
	{
	pjsip_host_info dest;
	struct result result;

	PJ_LOG(3,(THIS_FILE, " test_resolve(): %s", title));

	dest.type = type;
	dest.flag = pjsip_transport_get_flag_from_type(type);
	dest.addr.host = pj_str(name);
	dest.addr.port = port;

	result.status = 0x12345678;

	pjsip_endpt_resolve(endpt, pool, &dest, &result, &cb);

	while (result.status == 0x12345678) {
	int i = 0;
	pj_time_val timeout = { 1, 0 };
	pjsip_endpt_handle_events(endpt, &timeout);
	if (i == 1)
	pj_dns_resolver_dump(pjsip_endpt_get_resolver(endpt), PJ_TRUE);
	}

	if (result.status != PJ_SUCCESS) {
	app_perror(" pjsip_endpt_resolve() error", result.status);
	return result.status;
	}

	if (ref) {
	unsigned i;

	if (ref->count != result.servers.count) {
	PJ_LOG(3,(THIS_FILE, " test_resolve() error 10: result count mismatch"));
	return 10;
	}

	for (i=0; i<ref->count; ++i) {
	pj_sockaddr_in ra = (pj_sockaddr_in )&ref->entry[i].addr;
	pj_sockaddr_in rb = (pj_sockaddr_in )&result.servers.entry[i].addr;

	if (ra->sin_addr.s_addr != rb->sin_addr.s_addr) {
	PJ_LOG(3,(THIS_FILE, " test_resolve() error 20: IP address mismatch"));
	return 20;
	}
	if (ra->sin_port != rb->sin_port) {
	PJ_LOG(3,(THIS_FILE, " test_resolve() error 30: port mismatch"));
	return 30;
	}
	if (ref->entry[i].addr_len != result.servers.entry[i].addr_len) {
	PJ_LOG(3,(THIS_FILE, " test_resolve() error 40: addr_len mismatch"));
	return 40;
	}
	if (ref->entry[i].type != result.servers.entry[i].type) {
	PJ_LOG(3,(THIS_FILE, " test_resolve() error 50: transport type mismatch"));
	return 50;
	}
	}
	}

	return PJ_SUCCESS;
	}

	/*
	* Perform round-robin/load balance test.
	*/
	static int round_robin_test(pj_pool_t *pool)
	{
	enum { COUNT = 400, PCT_ALLOWANCE = 5 };
	unsigned i;
	struct server_hit
	{
	char *ip_addr;
	unsigned percent;
	unsigned hits;
	} server_hit[] =
	{
	{ "1.1.1.1", 3, 0 },
	{ "2.2.2.2", 65, 0 },
	{ "3.3.3.3", 32, 0 },
	{ "4.4.4.4", 0, 0 }
	};

	PJ_LOG(3,(THIS_FILE, " Performing round-robin/load-balance test.."));

	/* Do multiple resolve request to "example.com".
	* The resolver should select the server based on the weight proportion
	* the the servers in the SRV entry.
	*/
	for (i=0; i<COUNT; ++i) {
	pjsip_host_info dest;
	struct result result;
	unsigned j;

	dest.type = PJSIP_TRANSPORT_UDP;
	dest.flag = pjsip_transport_get_flag_from_type(PJSIP_TRANSPORT_UDP);
	dest.addr.host = pj_str("example.com");
	dest.addr.port = 0;

	result.status = 0x12345678;

	pjsip_endpt_resolve(endpt, pool, &dest, &result, &cb);

	while (result.status == 0x12345678) {
	int i = 0;
	pj_time_val timeout = { 1, 0 };
	pjsip_endpt_handle_events(endpt, &timeout);
	if (i == 1)
	pj_dns_resolver_dump(pjsip_endpt_get_resolver(endpt), PJ_TRUE);
	}

	/* Find which server was "hit" */
	for (j=0; j<PJ_ARRAY_SIZE(server_hit); ++j) {
	pj_str_t tmp;
	pj_in_addr a1;
	pj_sockaddr_in *a2;

	tmp = pj_str(server_hit[j].ip_addr);
	a1 = pj_inet_addr(&tmp);
	a2 = (pj_sockaddr_in*) &result.servers.entry[0].addr;

	if (a1.s_addr == a2->sin_addr.s_addr) {
	server_hit[j].hits++;
	break;
	}
	}

	if (j == PJ_ARRAY_SIZE(server_hit)) {
	PJ_LOG(1,(THIS_FILE, "..round_robin_test() error 10: returned address mismatch"));
	return 10;
	}
	}

	/* Print the actual hit rate */
	for (i=0; i<PJ_ARRAY_SIZE(server_hit); ++i) {
	PJ_LOG(3,(THIS_FILE, " ..Server %s: weight=%d%%, hit %d%% times",
	server_hit[i].ip_addr, server_hit[i].percent,
	(server_hit[i].hits * 100) / COUNT));
	}

	/* Compare the actual hit with the weight proportion */
	for (i=0; i<PJ_ARRAY_SIZE(server_hit); ++i) {
	int actual_pct = (server_hit[i].hits * 100) / COUNT;

	if (actual_pct + PCT_ALLOWANCE < (int)server_hit[i].percent \|\|
	actual_pct - PCT_ALLOWANCE > (int)server_hit[i].percent)
	{
	PJ_LOG(1,(THIS_FILE,
	"..round_robin_test() error 20: "
	"hit rate difference for server %s (%d%%) is more than "
	"tolerable allowance (%d%%)",
	server_hit[i].ip_addr,
	actual_pct - server_hit[i].percent,
	PCT_ALLOWANCE));
	return 20;
	}
	}

	PJ_LOG(3,(THIS_FILE,
	" Load balance test success, hit-rate is "
	"within %d%% allowance", PCT_ALLOWANCE));
	return PJ_SUCCESS;
	}


	#define C(expr) status = expr; \
	if (status != PJ_SUCCESS) app_perror(THIS_FILE, "Error", status);

	static void add_ref(pjsip_server_addresses *r,
	pjsip_transport_type_e type,
	char *addr,
	int port)
	{
	pj_sockaddr_in *a;
	pj_str_t tmp;

	r->entry[r->count].type = type;
	r->entry[r->count].priority = 0;
	r->entry[r->count].weight = 0;
	r->entry[r->count].addr_len = sizeof(pj_sockaddr_in);

	a = (pj_sockaddr_in *)&r->entry[r->count].addr;
	a->sin_family = PJ_AF_INET;
	tmp = pj_str(addr);
	a->sin_addr = pj_inet_addr(&tmp);
	a->sin_port = pj_htons((pj_uint16_t)port);

	r->count++;
	}

	static void create_ref(pjsip_server_addresses *r,
	pjsip_transport_type_e type,
	char *addr,
	int port)
	{
	r->count = 0;
	add_ref(r, type, addr, port);
	}


	/*
	* Main test entry.
	*/
	int resolve_test(void)
	{
	pj_pool_t *pool;
	pj_dns_resolver *resv;
	pj_str_t nameserver;
	pj_uint16_t port = 5353;
	pj_status_t status;

	pool = pjsip_endpt_create_pool(endpt, NULL, 4000, 4000);

	status = pjsip_endpt_create_resolver(endpt, &resv);

	nameserver = pj_str("192.168.0.106");
	pj_dns_resolver_set_ns(resv, 1, &nameserver, &port);
	pjsip_endpt_set_resolver(endpt, resv);

	add_dns_entries(resv);

	/* These all should be resolved as IP addresses (DNS A query) */
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_UDP, "1.1.1.1", 5060);
	status = test_resolve("IP address without transport and port", pool, PJSIP_TRANSPORT_UNSPECIFIED, "1.1.1.1", 0, &ref);
	if (status != PJ_SUCCESS)
	return -100;
	}
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_UDP, "1.1.1.1", 5060);
	status = test_resolve("IP address with explicit port", pool, PJSIP_TRANSPORT_UNSPECIFIED, "1.1.1.1", 5060, &ref);
	if (status != PJ_SUCCESS)
	return -110;
	}
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_TCP, "1.1.1.1", 5060);
	status = test_resolve("IP address without port (TCP)", pool, PJSIP_TRANSPORT_TCP,"1.1.1.1", 0, &ref);
	if (status != PJ_SUCCESS)
	return -120;
	}
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_TLS, "1.1.1.1", 5061);
	status = test_resolve("IP address without port (TLS)", pool, PJSIP_TRANSPORT_TLS, "1.1.1.1", 0, &ref);
	if (status != PJ_SUCCESS)
	return -130;
	}

	/* This should be resolved as DNS A record (because port is present) */
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_UDP, "5.5.5.5", 5060);
	status = test_resolve("domain name with port should resolve to A record", pool, PJSIP_TRANSPORT_UNSPECIFIED, "example.com", 5060, &ref);
	if (status != PJ_SUCCESS)
	return -140;
	}

	/* This will fail to be resolved as SRV, resolver should fallback to
	* resolving to A record.
	*/
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_UDP, "2.2.2.2", 5060);
	status = test_resolve("failure with SRV fallback to A record", pool, PJSIP_TRANSPORT_UNSPECIFIED, "sip02.example.com", 0, &ref);
	if (status != PJ_SUCCESS)
	return -150;
	}

	/* Same as above, but explicitly for TLS. */
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_TLS, "2.2.2.2", 5061);
	status = test_resolve("failure with SRV fallback to A record (for TLS)", pool, PJSIP_TRANSPORT_TLS, "sip02.example.com", 0, &ref);
	if (status != PJ_SUCCESS)
	return -150;
	}

	/* Standard DNS SRV followed by A recolution */
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_UDP, "6.6.6.6", 50060);
	status = test_resolve("standard SRV resolution", pool, PJSIP_TRANSPORT_UNSPECIFIED, "domain.com", 0, &ref);
	if (status != PJ_SUCCESS)
	return -155;
	}

	/* Standard DNS SRV followed by A recolution (explicit transport) */
	{
	pjsip_server_addresses ref;
	create_ref(&ref, PJSIP_TRANSPORT_TCP, "6.6.6.6", 50060);
	add_ref(&ref, PJSIP_TRANSPORT_TCP, "7.7.7.7", 50060);
	status = test_resolve("standard SRV resolution with explicit transport (TCP)", pool, PJSIP_TRANSPORT_TCP, "domain.com", 0, &ref);
	if (status != PJ_SUCCESS)
	return -160;
	}


	/* Round robin/load balance test */
	if (round_robin_test(pool) != 0)
	return -170;

	/* Timeout test */
	{
	status = test_resolve("timeout test", pool, PJSIP_TRANSPORT_UNSPECIFIED, "an.invalid.address", 0, NULL);
	if (status == PJ_SUCCESS)
	return -150;
	}

	return 0;
	}