Changeset 1357 for pjproject/trunk/pjlib-util/src/pjlib-util/srv_resolver.c

Timestamp:

Jun 11, 2007 4:51:18 PM (17 years ago)

Author:

bennylp

Message:

Ticket #330: Changed DNS SRV resolver to use the new DNS A response parser

File:

• pjproject/trunk/pjlib-util/src/pjlib-util/srv_resolver.c (modified) (8 diffs)

pjproject/trunk/pjlib-util/src/pjlib-util/srv_resolver.c

@@ -29 +29 @@
 #define THIS_FILE   "srv_resolver.c"
 
-#define ADDR_MAX_COUNT      8
+#define ADDR_MAX_COUNT      PJ_DNS_MAX_IP_IN_A_REC
 
 struct srv_target
@@ -53 +53 @@
     void                    *token;
     pj_dns_srv_resolver_cb  *cb;
-    pj_dns_async_query      *qobject;
     pj_status_t              last_error;
 
@@ -89 +88 @@
                                         pj_bool_t fallback_a,
                                         void *token,
-                                        pj_dns_srv_resolver_cb *cb)
+                                        pj_dns_srv_resolver_cb *cb,
+                                        pj_dns_async_query **p_query)
 {
     int len;
@@ -128 +128 @@
 
     PJ_LOG(5, (query_job->objname, 
-               "Starting async DNS %s query_job: target=%.*s",
+               "Starting async DNS %s query_job: target=%.*s:%d",
                pj_dns_get_type_name(query_job->dns_state),
-               (int)target_name.slen, target_name.ptr));
+               (int)target_name.slen, target_name.ptr,
+               def_port));
 
     status = pj_dns_resolver_start_query(resolver, &target_name, 
                                          query_job->dns_state, 0, 
                                          &dns_callback,
-                                         query_job, &query_job->qobject);
+                                         query_job, p_query);
     return status;
 }
@@ -466 +467 @@
         /* Check that we really have answer */
         if (status==PJ_SUCCESS && pkt->hdr.anscount != 0) {
-            int ans_idx = -1;
-
-            /* Find the first DNS A record in the answer while processing
-             * the CNAME info found in the response.
-             */
-            for (i=0; i < pkt->hdr.anscount; ++i) {
-
-                pj_dns_parsed_rr *rr = &pkt->ans[i];
-
-                if (rr->type == PJ_DNS_TYPE_A) {
-
-                    if (ans_idx == -1)
-                        ans_idx = i;
-
-                } else if (rr->type == PJ_DNS_TYPE_CNAME) {
-                    /* Find which server entry to be updated with
-                     * the CNAME information.
-                     */
-                    unsigned j;
-                    pj_str_t cname = rr->rdata.cname.name;
-
-                    for (j=0; j<query_job->srv_cnt; ++j) 
-                    {
-                        struct srv_target *srv = &query_job->srv[j];
-                        if (pj_stricmp(&rr->name, &srv->target_name)==0)
-                        {
-                            /* Update CNAME info for this server entry */
-                            srv->cname.ptr = srv->cname_buf;
-                            pj_strncpy(&srv->cname, &cname, 
-                                       sizeof(srv->cname_buf));
-                            break;
-                        }
-                    }
-                }
-            }
-
-            if (ans_idx == -1) {
-                /* There's no DNS A answer! */
-                PJ_LOG(5,(query_job->objname, 
-                          "No DNS A record in response!"));
-                status = PJLIB_UTIL_EDNSNOANSWERREC;
+            unsigned srv_idx;
+            struct srv_target *srv = NULL;
+            pj_dns_a_record rec;
+
+            /* Parse response */
+            status = pj_dns_parse_a_response(pkt, &rec);
+            if (status != PJ_SUCCESS)
                 goto on_error;
-            }
-
-            /* Update IP address of the corresponding hostname or CNAME */
-            for (i=0; i<query_job->srv_cnt; ++i) {
-                pj_dns_parsed_rr *rr = &pkt->ans[ans_idx];
-                struct srv_target *srv = &query_job->srv[i];
-
-                if (pj_stricmp(&rr->name, &srv->target_name)==0 ||
-                    pj_stricmp(&rr->name, &srv->cname)==0) 
-                {
+
+            pj_assert(rec.addr_count != 0);
+
+            /* Find which server entry to be updated. */
+            for (srv_idx=0; srv_idx<query_job->srv_cnt; ++srv_idx) {
+                srv = &query_job->srv[srv_idx];
+                if (pj_stricmp(&rec.name, &srv->target_name)==0) {
                     break;
                 }
             }
 
-            if (i == query_job->srv_cnt) {
-                PJ_LOG(4,(query_job->objname, 
-                          "Received answer to DNS A request with no matching "
-                          "SRV record! The unknown name is %.*s",
-                          (int)pkt->ans[ans_idx].name.slen, 
-                          pkt->ans[ans_idx].name.ptr));
+            if (srv_idx==query_job->srv_cnt) {
+                /* The DNS A response doesn't match any server names
+                 * we're querying!
+                 */
+                status = PJLIB_UTIL_EDNSINANSWER;
+                goto on_error;
+            }
+
+            srv = &query_job->srv[srv_idx];
+
+            /* Update CNAME alias, if present. */
+            if (rec.alias.slen) {
+                pj_assert(rec.alias.slen <= sizeof(srv->cname_buf));
+                srv->cname.ptr = srv->cname_buf;
+                pj_strcpy(&srv->cname, &rec.alias);
             } else {
-                unsigned j;
-
-                query_job->srv[i].addr[query_job->srv[i].addr_cnt++].s_addr =
-                    pkt->ans[ans_idx].rdata.a.ip_addr.s_addr;
+                srv->cname.slen = 0;
+            }
+
+            /* Update IP address of the corresponding hostname or CNAME */
+            if (srv->addr_cnt < ADDR_MAX_COUNT) {
+                srv->addr[srv->addr_cnt++].s_addr = rec.addr[0].s_addr;
 
                 PJ_LOG(5,(query_job->objname, 
                           "DNS A for %.*s: %s",
-                          (int)query_job->srv[i].target_name.slen, 
-                          query_job->srv[i].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_job->srv[i].addr_cnt < ADDR_MAX_COUNT; ++j)
-                {
-                    query_job->srv[i].addr[query_job->srv[i].addr_cnt++].s_addr = 
-                        pkt->ans[j].rdata.a.ip_addr.s_addr;
-
-                    PJ_LOG(5,(query_job->objname, 
-                              "Additional DNS A for %.*s: %s",
-                              (int)query_job->srv[i].target_name.slen, 
-                              query_job->srv[i].target_name.ptr,
-                              pj_inet_ntoa(pkt->ans[j].rdata.a.ip_addr)));
-                }
+                          (int)srv->target_name.slen, 
+                          srv->target_name.ptr,
+                          pj_inet_ntoa(rec.addr[0])));
+            }
+
+            /* Check for multiple IP addresses */
+            for (i=1; i<rec.addr_count && srv->addr_cnt < ADDR_MAX_COUNT; ++i)
+            {
+                srv->addr[srv->addr_cnt++].s_addr = rec.addr[i].s_addr;
+
+                PJ_LOG(5,(query_job->objname, 
+                          "Additional DNS A for %.*s: %s",
+                          (int)srv->target_name.slen, 
+                          srv->target_name.ptr,
+                          pj_inet_ntoa(rec.addr[i])));
             }
 
@@ -578 +551 @@
     if (query_job->host_resolved == query_job->srv_cnt) {
         /* Got all answers, build server addresses */
-        pj_dns_srv_record svr_addr;
-
-        svr_addr.count = 0;
+        pj_dns_srv_record srv_rec;
+
+        srv_rec.count = 0;
         for (i=0; i<query_job->srv_cnt; ++i) {
             unsigned j;
-
-            /* Do we have IP address for this server? */
-            /* This log is redundant really.
-            if (query_job->srv[i].addr_cnt == 0) {
-                PJ_LOG(5,(query_job->objname, 
-                          " SRV target %.*s:%d does not have IP address!",
-                          (int)query_job->srv[i].target_name.slen,
-                          query_job->srv[i].target_name.ptr,
-                          query_job->srv[i].port));
-                continue;
-            }
-            */
-
-            for (j=0; j<query_job->srv[i].addr_cnt; ++j) {
-                unsigned idx = svr_addr.count;
-                pj_sockaddr_in *addr;
-
-                svr_addr.entry[idx].priority = query_job->srv[i].priority;
-                svr_addr.entry[idx].weight = query_job->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_job->srv[i].addr[j];
-                addr->sin_port = pj_htons((pj_uint16_t)query_job->srv[i].port);
-
-                ++svr_addr.count;
+            struct srv_target *srv = &query_job->srv[i];
+
+            srv_rec.entry[srv_rec.count].priority = srv->priority;
+            srv_rec.entry[srv_rec.count].weight = srv->weight;
+            srv_rec.entry[srv_rec.count].port = (pj_uint16_t)srv->port ;
+
+            srv_rec.entry[srv_rec.count].server.name = srv->target_name;
+            srv_rec.entry[srv_rec.count].server.alias = srv->cname;
+            srv_rec.entry[srv_rec.count].server.addr_count = 0;
+
+            pj_assert(srv->addr_cnt <= PJ_DNS_MAX_IP_IN_A_REC);
+
+            for (j=0; j<srv->addr_cnt; ++j) {
+                srv_rec.entry[srv_rec.count].server.addr[j].s_addr = 
+                    srv->addr[j].s_addr;
+                ++srv_rec.entry[srv_rec.count].server.addr_count;
+            }
+
+            if (srv->addr_cnt > 0) {
+                ++srv_rec.count;
+                if (srv_rec.count == PJ_DNS_SRV_MAX_ADDR)
+                    break;
             }
         }
@@ -616 +583 @@
         PJ_LOG(5,(query_job->objname, 
                   "Server resolution complete, %d server entry(s) found",
-                  svr_addr.count));
-
-
-        if (svr_addr.count > 0)
+                  srv_rec.count));
+
+
+        if (srv_rec.count > 0)
             status = PJ_SUCCESS;
         else {
@@ -628 +595 @@
 
         /* Call the callback */
-        (*query_job->cb)(query_job->token, status, &svr_addr);
+        (*query_job->cb)(query_job->token, status, &srv_rec);
     }