Refactor find headers

Another recurring code pattern that can be moved into a separate
function.

Co-authored-by: Matthijs Mekking <matthijs@isc.org>

diff --git a/lib/dns/qpcache.c b/lib/dns/qpcache.c
index 7537b14449acfc680bfaeb56c787b66b8f309a27..071fbf2de5d956ab4a3aa3a31ba2f32540c14022 100644 (file)
--- a/lib/dns/qpcache.c
+++ b/lib/dns/qpcache.c
@@ -1288,6 +1288,20 @@ both_headers(dns_slabheader_t *header, dns_rdatatype_t type,
        return done;
 }
 
+static void
+find_headers(qpcnode_t *node, qpc_search_t *search, dns_rdatatype_t type,
+            dns_slabheader_t **found, dns_slabheader_t **foundsig) {
+       DNS_SLABTOP_FOREACH(top, node->data) {
+               dns_slabheader_t *header = first_header(top);
+               if (check_header(header, search)) {
+                       continue;
+               }
+               if (both_headers(header, type, found, foundsig)) {
+                       break;
+               }
+       }
+}
+
 static isc_result_t
 check_zonecut(qpcnode_t *node, void *arg DNS__DB_FLARG) {
        qpc_search_t *search = arg;
@@ -1304,18 +1318,7 @@ check_zonecut(qpcnode_t *node, void *arg DNS__DB_FLARG) {
        /*
         * Look for a DNAME or RRSIG DNAME rdataset.
         */
-       DNS_SLABTOP_FOREACH(top, node->data) {
-               dns_slabheader_t *header = first_header(top);
-               if (check_header(header, search)) {
-                       continue;
-               }
-
-               if (both_headers(header, dns_rdatatype_dname, &found,
-                                &foundsig))
-               {
-                       break;
-               }
-       }
+       find_headers(node, search, dns_rdatatype_dname, &found, &foundsig);
 
        if (found != NULL && (!DNS_TRUST_PENDING(atomic_load(&found->trust)) ||
                              (search->options & DNS_DBFIND_PENDINGOK) != 0))
@@ -1367,18 +1370,7 @@ find_deepest_zonecut(qpc_search_t *search, qpcnode_t *node,
                /*
                 * Look for NS and RRSIG NS rdatasets.
                 */
-               DNS_SLABTOP_FOREACH(top, node->data) {
-                       dns_slabheader_t *header = first_header(top);
-                       if (check_header(header, search)) {
-                               continue;
-                       }
-
-                       if (both_headers(header, dns_rdatatype_ns, &found,
-                                        &foundsig))
-                       {
-                               break;
-                       }
-               }
+               find_headers(node, search, dns_rdatatype_ns, &found, &foundsig);
 
                if (found != NULL) {
                        /*
@@ -1471,17 +1463,8 @@ find_coveringnsec(qpc_search_t *search, const dns_name_t *name,
 
        nlock = &search->qpdb->buckets[node->locknum].lock;
        NODE_RDLOCK(nlock, &nlocktype);
-       DNS_SLABTOP_FOREACH(top, node->data) {
-               dns_slabheader_t *header = first_header(top);
-               if (check_header(header, search)) {
-                       continue;
-               }
 
-               if (both_headers(header, dns_rdatatype_nsec, &found, &foundsig))
-               {
-                       break;
-               }
-       }
+       find_headers(node, search, dns_rdatatype_nsec, &found, &foundsig);
 
        if (found != NULL) {
                if (nodep != NULL) {
@@ -1944,33 +1927,7 @@ seek_ns_headers(qpc_search_t *search, qpcnode_t *node, dns_dbnode_t **nodep,
 
        NODE_RDLOCK(nlock, &nlocktype);
 
-       DNS_SLABTOP_FOREACH(top, node->data) {
-               bool ns = top->typepair == DNS_TYPEPAIR(dns_rdatatype_ns) ||
-                         top->typepair == DNS_SIGTYPEPAIR(dns_rdatatype_ns);
-               dns_slabheader_t *header = first_header(top);
-               if (header == NULL) {
-                       continue;
-               }
-
-               if (check_stale_header(header, search)) {
-                       if (ns) {
-                               /*
-                                * We found a cached NS, but was either
-                                * ancient or it was stale and serve-stale
-                                * is disabled, so this node can't be used
-                                * as a zone cut we know about. Instead we
-                                * bail out and call find_deepest_zonecut()
-                                * below.
-                                */
-                               break;
-                       }
-                       continue;
-               }
-
-               if (both_headers(header, dns_rdatatype_ns, &found, &foundsig)) {
-                       break;
-               }
-       }
+       find_headers(node, search, dns_rdatatype_ns, &found, &foundsig);
 
        if (found == NULL) {
                isc_result_t result;