Changeset 1326

Timestamp:

May 30, 2007 4:23:43 PM (17 years ago)

Author:

bennylp

Message:

Fixed ticket #313: Error resolving host in PJSIP resolver when DNS response contains CNAME (thanks Esbjörn Dominique)

File:

• pjproject/trunk/pjsip/src/pjsip/sip_resolve.c (modified) (3 diffs)

pjproject/trunk/pjsip/src/pjsip/sip_resolve.c

@@ -761 +761 @@
         if (status==PJ_SUCCESS && pkt->hdr.anscount != 0) {
 
+            unsigned srv_idx;
+
             /* Update IP address of the corresponding hostname */
-            for (i=0; i<query->srv_cnt; ++i) {
+            for (srv_idx=0; srv_idx<query->srv_cnt; ++srv_idx) {
                 if (pj_stricmp(&pkt->ans[0].name, 
-                               &query->srv[i].target_name)==0) 
+                               &query->srv[srv_idx].target_name)==0) 
                 {
                     break;
@@ -770 +772 @@
             }
 
-            if (i == query->srv_cnt) {
+            if (srv_idx == query->srv_cnt) {
                 PJ_LOG(4,(query->objname, 
                           "Received answer to DNS A request with no matching "
@@ -776 +778 @@
                           (int)pkt->ans[0].name.slen, pkt->ans[0].name.ptr));
             } else {
-                unsigned j;
-
-                query->srv[i].addr[query->srv[i].addr_cnt++].s_addr =
-                    pkt->ans[0].rdata.a.ip_addr.s_addr;
+                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[i].target_name.slen, 
-                          query->srv[i].target_name.ptr,
-                          pj_inet_ntoa(pkt->ans[0].rdata.a.ip_addr)));
+                          (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=1; j<pkt->hdr.anscount && 
-                            query->srv[i].addr_cnt < ADDR_MAX_COUNT; ++j)
+                for (j=ans_idx+1; j<pkt->hdr.anscount && 
+                            query->srv[srv_idx].addr_cnt < ADDR_MAX_COUNT; ++j)
                 {
-                    query->srv[i].addr[query->srv[i].addr_cnt++].s_addr = 
+                    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[i].target_name.slen, 
-                              query->srv[i].target_name.ptr,
+                              (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)));
                 }