Ticket #331: Changed PJSIP DNS SRV resolver to use PJLIB-UTIL DNS SRV resolver

git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@1358 74dad513-b988-da41-8d7b-12977e46ad98

1 files changed, 127 insertions, 595 deletions

diff --git a/pjsip/src/pjsip/sip_resolve.c b/pjsip/src/pjsip/sip_resolve.c
index 98c3650d..367d3fc4 100644
--- a/pjsip/src/pjsip/sip_resolve.c
+++ b/pjsip/src/pjsip/sip_resolve.c
@@ -20,6 +20,7 @@
 #include <pjsip/sip_transport.h>
 #include <pjsip/sip_errno.h>
 #include <pjlib-util/errno.h>
+#include <pjlib-util/srv_resolver.h>
 #include <pj/array.h>
 #include <pj/assert.h>
 #include <pj/ctype.h>
@@ -35,31 +36,18 @@
 
 struct naptr_target
 {
-    pj_str_t		    target_name;    /**< NAPTR target name. */
+    pj_str_t		    res_type;	    /**< e.g. "_sip._udp"   */
+    pj_str_t		    name;	    /**< Domain name.	    */
     pjsip_transport_type_e  type;	    /**< Transport type.    */
     unsigned		    order;	    /**< Order		    */
     unsigned		    pref;	    /**< Preference.	    */
 };
 
-struct srv_target
-{
-    pjsip_transport_type_e  type;
-    pj_str_t		    target_name;
-    char		    target_buf[PJ_MAX_HOSTNAME];
-    unsigned		    port;
-    unsigned		    priority;
-    unsigned		    weight;
-    unsigned		    sum;
-    unsigned		    addr_cnt;
-    pj_in_addr		    addr[ADDR_MAX_COUNT];
-};
-
 struct query
 {
-    char		     objname[PJ_MAX_OBJ_NAME];
+    char		    *objname;
 
-    pjsip_resolver_t	    *resolver;	    /**< Resolver SIP instance.	    */
-    pj_dns_type		     dns_state;	    /**< DNS type being resolved.   */
+    pj_dns_type		     query_type;
     void		    *token;
     pjsip_resolver_callback *cb;
     pj_dns_async_query	    *object;
@@ -68,30 +56,27 @@ struct query
     /* Original request: */
     struct {
 	pjsip_host_info	     target;
+	unsigned	     def_port;
     } req;
 
     /* NAPTR records: */
     unsigned		     naptr_cnt;
     struct naptr_target	     naptr[8];
-
-    /* SRV records and their resolved IP addresses: */
-    unsigned		     srv_cnt;
-    struct srv_target	     srv[PJSIP_MAX_RESOLVED_ADDRESSES];
-
-    /* Number of hosts in SRV records that the IP address has been resolved */
-    unsigned		     host_resolved;
 };
 
 
 struct pjsip_resolver_t
 {
     pj_dns_resolver *res;
-    unsigned	     job_id;
 };
 
-static void dns_callback(void *user_data,
-			 pj_status_t status,
-			 pj_dns_parsed_packet *response);
+
+static void srv_resolver_cb(void *user_data,
+			    pj_status_t status,
+			    const pj_dns_srv_record *rec);
+static void dns_a_callback(void *user_data,
+			   pj_status_t status,
+			   pj_dns_parsed_packet *response);
 
 
 /*
@@ -183,7 +168,6 @@ PJ_DEF(void) pjsip_resolve( pjsip_resolver_t *resolver,
     pj_status_t status = PJ_SUCCESS;
     int is_ip_addr;
     struct query *query;
-    pj_str_t srv_name;
     pjsip_transport_type_e type = target->type;
 
     /* Is it IP address or hostname?. */
@@ -279,9 +263,7 @@ PJ_DEF(void) pjsip_resolve( pjsip_resolver_t *resolver,
 
     /* Build the query state */
     query = PJ_POOL_ZALLOC_T(pool, struct query);
-    pj_ansi_snprintf(query->objname, sizeof(query->objname), "rsvjob%X",
-		     resolver->job_id++);
-    query->resolver = resolver;
+    query->objname = THIS_FILE;
     query->token = token;
     query->cb = cb;
     query->req.target = *target;
@@ -298,60 +280,68 @@ PJ_DEF(void) pjsip_resolve( pjsip_resolver_t *resolver,
     query->naptr[0].order = 0;
     query->naptr[0].pref = 0;
     query->naptr[0].type = type;
-    query->naptr[0].target_name.ptr = (char*)
-	pj_pool_alloc(pool, target->addr.host.slen + 12);
-
-    if (type == PJSIP_TRANSPORT_TLS)
-	pj_strcpy2(&query->naptr[0].target_name, "_sips._tcp.");
-    else if (type == PJSIP_TRANSPORT_TCP)
-	pj_strcpy2(&query->naptr[0].target_name, "_sip._tcp.");
-    else if (type == PJSIP_TRANSPORT_UDP)
-	pj_strcpy2(&query->naptr[0].target_name, "_sip._udp.");
-    else {
-	pj_assert(!"Unknown transport type");
-	pj_strcpy2(&query->naptr[0].target_name, "_sip._udp.");
-    }
-    pj_strcat(&query->naptr[0].target_name, &target->addr.host);
+    pj_strdup(pool, &query->naptr[0].name, &target->addr.host);
 
 
     /* Start DNS SRV or A resolution, depending on whether port is specified */
     if (target->addr.port == 0) {
-	query->dns_state = PJ_DNS_TYPE_SRV;
-	srv_name = query->naptr[0].target_name;
+	query->query_type = PJ_DNS_TYPE_SRV;
+
+	query->req.def_port = 5060;
+
+	if (type == PJSIP_TRANSPORT_TLS) {
+	    query->naptr[0].res_type = pj_str("_sips._tcp.");
+	    query->req.def_port = 5061;
+	} else if (type == PJSIP_TRANSPORT_TCP)
+	    query->naptr[0].res_type = pj_str("_sip._tcp.");
+	else if (type == PJSIP_TRANSPORT_UDP)
+	    query->naptr[0].res_type = pj_str("_sip._udp.");
+	else {
+	    pj_assert(!"Unknown transport type");
+	    query->naptr[0].res_type = pj_str("_sip._udp.");
+	    
+	}
 
     } else {
 	/* Otherwise if port is specified, start with A (or AAAA) host 
 	 * resolution 
 	 */
-	query->dns_state = PJ_DNS_TYPE_A;
-
-	/* Since we don't perform SRV resolution, pretend that we'ee already
-	 * done so by inserting a dummy SRV record.
-	 */
-
-	query->srv_cnt = 1;
-	pj_bzero(&query->srv[0], sizeof(query->srv[0]));
-	query->srv[0].target_name = query->req.target.addr.host;
-	query->srv[0].type = type;
-	query->srv[0].port = query->req.target.addr.port;
-	query->srv[0].priority = 0;
-	query->srv[0].weight = 0;
-
-	srv_name = query->srv[0].target_name;
+	query->query_type = PJ_DNS_TYPE_A;
+	query->naptr[0].res_type.slen = 0;
+	query->req.def_port = target->addr.port;
     }
 
     /* Start the asynchronous query */
     PJ_LOG(5, (query->objname, 
-	       "Starting async DNS %s query: target=%.*s, transport=%s, "
+	       "Starting async DNS %s query: target=%.*s%.*s, transport=%s, "
 	       "port=%d",
-	       pj_dns_get_type_name(query->dns_state),
-	       (int)srv_name.slen, srv_name.ptr,
+	       pj_dns_get_type_name(query->query_type),
+	       (int)query->naptr[0].res_type.slen,
+	       query->naptr[0].res_type.ptr,
+	       (int)query->naptr[0].name.slen, query->naptr[0].name.ptr,
 	       pjsip_transport_get_type_name(target->type),
 	       target->addr.port));
 
-    status = pj_dns_resolver_start_query(resolver->res, &srv_name, 
-				         query->dns_state, 0, &dns_callback,
-    					 query, &query->object);
+    if (query->query_type == PJ_DNS_TYPE_SRV) {
+
+	status = pj_dns_srv_resolve(&query->naptr[0].name,
+				    &query->naptr[0].res_type,
+				    query->req.def_port, pool, resolver->res,
+				    PJ_TRUE, query, &srv_resolver_cb, NULL);
+
+    } else if (query->query_type == PJ_DNS_TYPE_A) {
+
+	status = pj_dns_resolver_start_query(resolver->res, 
+					     &query->naptr[0].name,
+					     PJ_DNS_TYPE_A, 0, 
+					     &dns_a_callback,
+    					     query, &query->object);
+
+    } else {
+	pj_assert(!"Unexpected");
+	status = PJ_EBUG;
+    }
+
     if (status != PJ_SUCCESS)
 	goto on_error;
 
@@ -376,562 +366,104 @@ on_error:
     }
 }
 
-/*
- * The rest of the code should only get compiled when resolver is enabled
- */
 #if PJSIP_HAS_RESOLVER
 
-#define SWAP(type,ptr1,ptr2)	if (ptr1 != ptr2) { \
-				  type tmp; \
-				  pj_memcpy(&tmp, ptr1, sizeof(type)); \
-				  pj_memcpy(ptr1, ptr2, sizeof(type)); \
-				  (ptr1)->target_name.ptr = (ptr1)->target_buf; \
-				  pj_memcpy(ptr2, &tmp, sizeof(type)); \
-				  (ptr2)->target_name.ptr = (ptr2)->target_buf; \
-				} else {}
-
-/* Build server entries in the query based on received SRV response */
-static void build_server_entries(struct query *query, 
-				 pj_dns_parsed_packet *response)
+/* 
+ * This callback is called when target is resolved with DNS A query.
+ */
+static void dns_a_callback(void *user_data,
+			   pj_status_t status,
+			   pj_dns_parsed_packet *pkt)
 {
+    struct query *query = (struct query*) user_data;
+    pjsip_server_addresses srv;
+    pj_dns_a_record rec;
     unsigned i;
-    unsigned naptr_id;
-
-    /* Find NAPTR target which corresponds to this SRV target */
-    for (naptr_id=0; naptr_id < query->naptr_cnt; ++naptr_id) {
-	if (pj_stricmp(&query->naptr[naptr_id].target_name,
-		       &response->ans[0].name)==0)
-	    break;
-    }
-    if (naptr_id == query->naptr_cnt) {
-	PJ_LOG(4,(query->objname, 
-		  "Unable to find NAPTR record for SRV name %.*s!",
-		  (int)response->ans[0].name.slen, 
-		  response->ans[0].name.ptr));
-	return;
-    }
 
+    rec.addr_count = 0;
 
-    /* Save the Resource Records in DNS answer into SRV targets. */
-    query->srv_cnt = 0;
-    for (i=0; i<response->hdr.anscount && 
-	      query->srv_cnt < PJSIP_MAX_RESOLVED_ADDRESSES; ++i) 
-    {
-	pj_dns_parsed_rr *rr = &response->ans[i];
-	struct srv_target *srv = &query->srv[query->srv_cnt];
-
-	if (rr->type != PJ_DNS_TYPE_SRV) {
-	    PJ_LOG(4,(query->objname, 
-		      "Received non SRV answer for SRV query!"));
-	    continue;
-	}
-
-	if (rr->rdata.srv.target.slen > PJ_MAX_HOSTNAME) {
-	    PJ_LOG(4,(query->objname, "Hostname is too long!"));
-	    continue;
-	}
-
-	/* Build the SRV entry for RR */
-	pj_bzero(srv, sizeof(*srv));
-	pj_memcpy(srv->target_buf, rr->rdata.srv.target.ptr, 
-		  rr->rdata.srv.target.slen);
-	srv->target_name.ptr = srv->target_buf;
-	srv->target_name.slen = rr->rdata.srv.target.slen;
-	srv->type = query->naptr[naptr_id].type;
-	srv->port = rr->rdata.srv.port;
-	srv->priority = rr->rdata.srv.prio;
-	srv->weight = rr->rdata.srv.weight;
-	
-	++query->srv_cnt;
+    /* Parse the response */
+    if (status == PJ_SUCCESS) {
+	status = pj_dns_parse_a_response(pkt, &rec);
     }
 
-    /* First pass: 
-     *	order the entries based on priority.
-     */
-    for (i=0; i<query->srv_cnt-1; ++i) {
-	unsigned min = i, j;
-	for (j=i+1; j<query->srv_cnt; ++j) {
-	    if (query->srv[j].priority < query->srv[min].priority)
-		min = j;
-	}
-	SWAP(struct srv_target, &query->srv[i], &query->srv[min]);
-    }
-
-    /* Second pass:
-     *	pick one host among hosts with the same priority, according
-     *	to its weight. The idea is when one server fails, client should
-     *	contact the next server with higher priority rather than contacting
-     *	server with the same priority as the failed one.
-     *
-     *  The algorithm for selecting server among servers with the same
-     *  priority is described in RFC 2782.
-     */
-    for (i=0; i<query->srv_cnt; ++i) {
-	unsigned j, count=1, sum;
-
-	/* Calculate running sum for servers with the same priority */
-	sum = query->srv[i].sum = query->srv[i].weight;
-	for (j=i+1; j<query->srv_cnt && 
-		    query->srv[j].priority == query->srv[i].priority; ++j)
-	{
-	    sum += query->srv[j].weight;
-	    query->srv[j].sum = sum;
-	    ++count;
-	}
-
-	if (count > 1) {
-	    unsigned r;
-
-	    /* Elect one random number between zero and the total sum of
-	     * weight (inclusive).
-	     */
-	    r = pj_rand() % (sum + 1);
-
-	    /* Select the first server which running sum is greater than or
-	     * equal to the random number.
-	     */
-	    for (j=i; j<i+count; ++j) {
-		if (query->srv[j].sum >= r)
-		    break;
-	    }
-
-	    /* Must have selected one! */
-	    pj_assert(j != i+count);
-
-	    /* Put this entry in front (of entries with same priority) */
-	    SWAP(struct srv_target, &query->srv[i], &query->srv[j]);
+    if (status != PJ_SUCCESS) {
+	char errmsg[PJ_ERR_MSG_SIZE];
 
-	    /* Remove all other entries (of the same priority) */
-	    while (count > 1) {
-		pj_array_erase(query->srv, sizeof(struct srv_target), 
-			       query->srv_cnt, i+1);
-		--count;
-		--query->srv_cnt;
-	    }
-	}
-    }
+	/* Log error */
+	pj_strerror(status, errmsg, sizeof(errmsg));
+	PJ_LOG(4,(query->objname, "DNS A record resolution failed: %s", 
+		  errmsg));
 
-    /* Since we've been moving around SRV entries, update the pointers
-     * in target_name.
-     */
-    for (i=0; i<query->srv_cnt; ++i) {
-	query->srv[i].target_name.ptr = query->srv[i].target_buf;
+	/* Call the callback */
+	(*query->cb)(status, query->token, NULL);
+	return;
     }
 
-    /* Check for Additional Info section if A records are available, and
-     * fill in the IP address (so that we won't need to resolve the A 
-     * record with another DNS query). 
-     */
-    for (i=0; i<response->hdr.arcount; ++i) {
-	pj_dns_parsed_rr *rr = &response->arr[i];
-	unsigned j;
-
-	if (rr->type != PJ_DNS_TYPE_A)
-	    continue;
-
-	/* Yippeaiyee!! There is an "A" record! 
-	 * Update the IP address of the corresponding SRV record.
-	 */
-	for (j=0; j<query->srv_cnt; ++j) {
-	    if (pj_stricmp(&rr->name, &query->srv[j].target_name)==0) {
-		unsigned cnt = query->srv[j].addr_cnt;
-		query->srv[j].addr[cnt].s_addr = rr->rdata.a.ip_addr.s_addr;
-		++query->srv[j].addr_cnt;
-		++query->host_resolved;
-		break;
-	    }
-	}
-
-	/* Not valid message; SRV entry might have been deleted in
-	 * server selection process.
-	 */
-	/*
-	if (j == query->srv_cnt) {
-	    PJ_LOG(4,(query->objname, 
-		      "Received DNS SRV answer with A record, but "
-		      "couldn't find matching name (name=%.*s)",
-		      (int)rr->name.slen,
-		      rr->name.ptr));
-	}
-	*/
+    /* Build server addresses and call callback */
+    srv.count = 0;
+    for (i=0; i<rec.addr_count; ++i) {
+	srv.entry[srv.count].type = query->naptr[0].type;
+	srv.entry[srv.count].priority = 0;
+	srv.entry[srv.count].weight = 0;
+	srv.entry[srv.count].addr_len = sizeof(pj_sockaddr_in);
+	pj_sockaddr_in_init(&srv.entry[srv.count].addr.ipv4,
+			    0, (pj_uint16_t)query->req.def_port);
+	srv.entry[srv.count].addr.ipv4.sin_addr.s_addr =
+	    rec.addr[i].s_addr;
+
+	++srv.count;
     }
 
-    /* Rescan again the name specified in the SRV record to see if IP
-     * address is specified as the target name (unlikely, but well, who 
-     * knows..).
-     */
-    for (i=0; i<query->srv_cnt; ++i) {
-	pj_in_addr addr;
-
-	if (query->srv[i].addr_cnt != 0) {
-	    /* IP address already resolved */
-	    continue;
-	}
-
-	if (pj_inet_aton(&query->srv[i].target_name, &addr) != 0) {
-	    query->srv[i].addr[query->srv[i].addr_cnt++] = addr;
-	    ++query->host_resolved;
-	}
-    }
-
-    /* Print resolved entries to the log */
-    PJ_LOG(5,(query->objname, 
-	      "SRV query for %.*s completed, "
-	      "%d of %d total entries selected%c",
-	      (int)query->naptr[naptr_id].target_name.slen,
-	      query->naptr[naptr_id].target_name.ptr,
-	      query->srv_cnt,
-	      response->hdr.anscount,
-	      (query->srv_cnt ? ':' : ' ')));
-
-    for (i=0; i<query->srv_cnt; ++i) {
-	const char *addr;
-
-	if (query->srv[i].addr_cnt != 0)
-	    addr = pj_inet_ntoa(query->srv[i].addr[0]);
-	else
-	    addr = "-";
-
-	PJ_LOG(5,(query->objname, 
-		  " %d: SRV %d %d %d %.*s (%s)",
-		  i, query->srv[i].priority, 
-		  query->srv[i].weight, 
-		  query->srv[i].port, 
-		  (int)query->srv[i].target_name.slen, 
-		  query->srv[i].target_name.ptr,
-		  addr));
-    }
+    /* Call the callback */
+    (*query->cb)(PJ_SUCCESS, query->token, &srv);
 }
 
 
-/* Start DNS A record queries for all SRV records in the query structure */
-static pj_status_t resolve_hostnames(struct query *query)
-{
-    unsigned i;
-    pj_status_t err=PJ_SUCCESS, status;
-
-    query->dns_state = PJ_DNS_TYPE_A;
-    for (i=0; i<query->srv_cnt; ++i) {
-	PJ_LOG(5, (query->objname, 
-		   "Starting async DNS A query for %.*s",
-		   (int)query->srv[i].target_name.slen, 
-		   query->srv[i].target_name.ptr));
-
-	status = pj_dns_resolver_start_query(query->resolver->res,
-					     &query->srv[i].target_name,
-					     PJ_DNS_TYPE_A, 0,
-					     &dns_callback,
-					     query, NULL);
-	if (status != PJ_SUCCESS) {
-	    query->host_resolved++;
-	    err = status;
-	}
-    }
-    
-    return (query->host_resolved == query->srv_cnt) ? err : PJ_SUCCESS;
-}
-
-/* 
- * This callback is called by PJLIB-UTIL DNS resolver when asynchronous
- * query has completed (successfully or with error).
- */
-static void dns_callback(void *user_data,
-			 pj_status_t status,
-			 pj_dns_parsed_packet *pkt)
+/* Callback to be called by DNS SRV resolution */
+static void srv_resolver_cb(void *user_data,
+			    pj_status_t status,
+			    const pj_dns_srv_record *rec)
 {
     struct query *query = (struct query*) user_data;
+    pjsip_server_addresses srv;
     unsigned i;
 
-    /* Proceed to next stage */
-
-    if (query->dns_state == PJ_DNS_TYPE_SRV) {
-
-	/* We are getting SRV response */
-
-	if (status == PJ_SUCCESS && pkt->hdr.anscount != 0) {
-	    /* Got SRV response, build server entry. If A records are available
-	     * in additional records section of the DNS response, save them too.
-	     */
-	    build_server_entries(query, pkt);
-
-	} else if (status != PJ_SUCCESS) {
-	    char errmsg[PJ_ERR_MSG_SIZE];
-	    unsigned naptr_id;
-
-	    /* Update query last error */
-	    query->last_error = status;
-
-	    /* Find which NAPTR target has not got SRV records */
-	    for (naptr_id=0; naptr_id < query->naptr_cnt; ++naptr_id) {
-		for (i=0; i<query->srv_cnt; ++i) {
-		    if (query->srv[i].type == query->naptr[naptr_id].type)
-			break;
-		}
-		if (i == query->srv_cnt)
-		    break;
-	    }
-	    if (naptr_id == query->naptr_cnt) {
-		/* Strangely all NAPTR records seem to already have SRV
-		 * records! This is quite unexpected, by anyway lets set
-		 * the naptr_id to zero just in case.
-		 */
-		pj_assert(!"Strange");
-		naptr_id = 0;
-
-	    }
-
-	    pj_strerror(status, errmsg, sizeof(errmsg));
-	    PJ_LOG(4,(query->objname, 
-		      "DNS SRV resolution failed for %.*s: %s", 
-		      (int)query->naptr[naptr_id].target_name.slen, 
-		      query->naptr[naptr_id].target_name.ptr,
-		      errmsg));
-	}
-
-	/* If we can't build SRV record, assume the original target is
-	 * an A record.
-	 */
-	if (query->srv_cnt == 0) {
-	    /* Looks like we aren't getting any SRV responses.
-	     * Resolve the original target as A record by creating a 
-	     * single "dummy" srv record and start the hostname resolution.
-	     */
-	    unsigned naptr_id;
-
-	    /* Find which NAPTR target has not got SRV records */
-	    for (naptr_id=0; naptr_id < query->naptr_cnt; ++naptr_id) {
-		for (i=0; i<query->srv_cnt; ++i) {
-		    if (query->srv[i].type == query->naptr[naptr_id].type)
-			break;
-		}
-		if (i == query->srv_cnt)
-		    break;
-	    }
-	    if (naptr_id == query->naptr_cnt) {
-		/* Strangely all NAPTR records seem to already have SRV
-		 * records! This is quite unexpected, by anyway lets set
-		 * the naptr_id to zero just in case.
-		 */
-		pj_assert(!"Strange");
-		naptr_id = 0;
-
-	    }
-
-	    PJ_LOG(4, (query->objname, 
-		       "DNS SRV resolution failed for %.*s, trying "
-		       "resolving A record for %.*s",
-		       (int)query->naptr[naptr_id].target_name.slen, 
-		       query->naptr[naptr_id].target_name.ptr,
-		       (int)query->req.target.addr.host.slen,
-		       query->req.target.addr.host.ptr));
-
-	    /* Create a "dummy" srv record using the original target */
-	    i = query->srv_cnt++;
-	    pj_bzero(&query->srv[i], sizeof(query->srv[i]));
-	    query->srv[i].target_name = query->req.target.addr.host;
-	    query->srv[i].type = query->naptr[naptr_id].type;
-	    query->srv[i].priority = 0;
-	    query->srv[i].weight = 0;
-
-	    query->srv[i].port = query->req.target.addr.port;
-	    if (query->srv[i].port == 0) {
-		query->srv[i].port = (pj_uint16_t)
-		 pjsip_transport_get_default_port_for_type(query->srv[i].type);
-	    }
-	} 
-	
-
-	/* Resolve server hostnames (DNS A record) for hosts which don't have
-	 * A record yet.
-	 */
-	if (query->host_resolved != query->srv_cnt) {
-	    status = resolve_hostnames(query);
-	    if (status != PJ_SUCCESS)
-		goto on_error;
-
-	    /* Must return now. Callback may have been called and query
-	     * may have been destroyed.
-	     */
-	    return;
-	}
-
-    } else if (query->dns_state == PJ_DNS_TYPE_A) {
-
-	/* Check that we really have answer */
-	if (status==PJ_SUCCESS && pkt->hdr.anscount != 0) {
-
-	    unsigned srv_idx;
-
-	    /* Update IP address of the corresponding hostname */
-	    for (srv_idx=0; srv_idx<query->srv_cnt; ++srv_idx) {
-		if (pj_stricmp(&pkt->ans[0].name, 
-			       &query->srv[srv_idx].target_name)==0) 
-		{
-		    break;
-		}
-	    }
-
-	    if (srv_idx == query->srv_cnt) {
-		PJ_LOG(4,(query->objname, 
-			  "Received answer to DNS A request with no matching "
-			  "SRV record! The unknown name is %.*s",
-			  (int)pkt->ans[0].name.slen, pkt->ans[0].name.ptr));
-	    } else {
-		int ans_idx = -1;
-		unsigned k, j;
-		pj_str_t cname = { NULL, 0 };
-
-		/* Find the first DNS A record in the answer while processing
-		 * the CNAME info found in the response.
-		 */
-		for (k=0; k < pkt->hdr.anscount; ++k) {
-
-		    pj_dns_parsed_rr *rr = &pkt->ans[k];
-
-		    if (rr->type == PJ_DNS_TYPE_A &&
-			(cname.slen == 0 || pj_stricmp(&rr->name, &cname)==0))
-		    {
-			if (ans_idx == -1)
-			    ans_idx = k;
-
-		    } else if (rr->type == PJ_DNS_TYPE_CNAME &&
-			       pj_stricmp(&query->srv[srv_idx].target_name, 
-				          &rr->name)==0) 
-		    {
-			cname = rr->rdata.cname.name;
-		    }
-		}
-
-		if (ans_idx == -1) {
-		    /* There's no DNS A answer! */
-		    PJ_LOG(5,(query->objname, 
-			      "No DNS A record in response!"));
-		    status = PJLIB_UTIL_EDNSNOANSWERREC;
-		    goto on_error;
-		}
-
-		query->srv[srv_idx].addr[query->srv[srv_idx].addr_cnt++].s_addr =
-		    pkt->ans[ans_idx].rdata.a.ip_addr.s_addr;
-
-		PJ_LOG(5,(query->objname, 
-			  "DNS A for %.*s: %s",
-			  (int)query->srv[srv_idx].target_name.slen, 
-			  query->srv[srv_idx].target_name.ptr,
-			  pj_inet_ntoa(pkt->ans[ans_idx].rdata.a.ip_addr)));
-
-		/* Check for multiple IP addresses */
-		for (j=ans_idx+1; j<pkt->hdr.anscount && 
-			    query->srv[srv_idx].addr_cnt < ADDR_MAX_COUNT; ++j)
-		{
-		    query->srv[srv_idx].addr[query->srv[srv_idx].addr_cnt++].s_addr = 
-			pkt->ans[j].rdata.a.ip_addr.s_addr;
-
-		    PJ_LOG(5,(query->objname, 
-			      "Additional DNS A for %.*s: %s",
-			      (int)query->srv[srv_idx].target_name.slen, 
-			      query->srv[srv_idx].target_name.ptr,
-			      pj_inet_ntoa(pkt->ans[j].rdata.a.ip_addr)));
-		}
-	    }
-
-	} else if (status != PJ_SUCCESS) {
-	    char errmsg[PJ_ERR_MSG_SIZE];
-
-	    /* Update last error */
-	    query->last_error = status;
-
-	    /* Log error */
-	    pj_strerror(status, errmsg, sizeof(errmsg));
-	    PJ_LOG(4,(query->objname, "DNS A record resolution failed: %s", 
-		      errmsg));
-	}
+    if (status != PJ_SUCCESS) {
+	char errmsg[PJ_ERR_MSG_SIZE];
 
-	++query->host_resolved;
+	/* Log error */
+	pj_strerror(status, errmsg, sizeof(errmsg));
+	PJ_LOG(4,(query->objname, "DNS A record resolution failed: %s", 
+		  errmsg));
 
-    } else {
-	pj_assert(!"Unexpected state!");
-	query->last_error = status = PJ_EINVALIDOP;
-	goto on_error;
+	/* Call the callback */
+	(*query->cb)(status, query->token, NULL);
+	return;
     }
 
-    /* Check if all hosts have been resolved */
-    if (query->host_resolved == query->srv_cnt) {
-	/* Got all answers, build server addresses */
-	pjsip_server_addresses svr_addr;
-
-	svr_addr.count = 0;
-	for (i=0; i<query->srv_cnt; ++i) {
-	    unsigned j;
-
-	    /* Do we have IP address for this server? */
-	    /* This log is redundant really.
-	    if (query->srv[i].addr_cnt == 0) {
-		PJ_LOG(5,(query->objname, 
-			  " SRV target %.*s:%d does not have IP address!",
-			  (int)query->srv[i].target_name.slen,
-			  query->srv[i].target_name.ptr,
-			  query->srv[i].port));
-		continue;
-	    }
-	    */
-
-	    for (j=0; j<query->srv[i].addr_cnt; ++j) {
-		unsigned idx = svr_addr.count;
-		pj_sockaddr_in *addr;
-
-		svr_addr.entry[idx].type = query->srv[i].type;
-		svr_addr.entry[idx].priority = query->srv[i].priority;
-		svr_addr.entry[idx].weight = query->srv[i].weight;
-		svr_addr.entry[idx].addr_len = sizeof(pj_sockaddr_in);
-	     
-		addr = (pj_sockaddr_in*)&svr_addr.entry[idx].addr;
-		pj_bzero(addr, sizeof(pj_sockaddr_in));
-		addr->sin_family = PJ_AF_INET;
-		addr->sin_addr = query->srv[i].addr[j];
-		addr->sin_port = pj_htons((pj_uint16_t)query->srv[i].port);
-
-		++svr_addr.count;
-	    }
-	}
-
-	PJ_LOG(5,(query->objname, 
-		  "Server resolution complete, %d server entry(s) found",
-		  svr_addr.count));
-
+    /* Build server addresses and call callback */
+    srv.count = 0;
+    for (i=0; i<rec->count; ++i) {
+	unsigned j;
 
-	if (svr_addr.count > 0)
-	    status = PJ_SUCCESS;
-	else {
-	    status = query->last_error;
-	    if (status == PJ_SUCCESS)
-		status = PJLIB_UTIL_EDNSNOANSWERREC;
+	for (j=0; j<rec->entry[i].server.addr_count; ++j) {
+	    srv.entry[srv.count].type = query->naptr[0].type;
+	    srv.entry[srv.count].priority = rec->entry[i].priority;
+	    srv.entry[srv.count].weight = rec->entry[i].weight;
+	    srv.entry[srv.count].addr_len = sizeof(pj_sockaddr_in);
+	    pj_sockaddr_in_init(&srv.entry[srv.count].addr.ipv4,
+				0, (pj_uint16_t)rec->entry[i].port);
+	    srv.entry[srv.count].addr.ipv4.sin_addr.s_addr =
+		rec->entry[i].server.addr[j].s_addr;
+
+	    ++srv.count;
 	}
-
-	/* Call the callback */
-	(*query->cb)(status, query->token, &svr_addr);
     }
 
-
-    return;
-
-on_error:
-    /* Check for failure */
-    if (status != PJ_SUCCESS) {
-	char errmsg[PJ_ERR_MSG_SIZE];
-	PJ_LOG(4,(query->objname, 
-		  "DNS %s record resolution error for '%.*s'."
-		  " Err=%d (%s)",
-		  pj_dns_get_type_name(query->dns_state),
-		  (int)query->req.target.addr.host.slen,
-		  query->req.target.addr.host.ptr,
-		  status,
-		  pj_strerror(status,errmsg,sizeof(errmsg)).ptr));
-	(*query->cb)(status, query->token, NULL);
-	return;
-    }
+    /* Call the callback */
+    (*query->cb)(PJ_SUCCESS, query->token, &srv);
 }
 
 #endif	/* PJSIP_HAS_RESOLVER */
 
-
-