Refactor the search in qpcache_findrdataset()

Add new related_headers() function that simplifies the code
flow in qpcache_findrdataset().  Also use check_stale_header() function
to remove code duplication.

diff --git a/lib/dns/qpcache.c b/lib/dns/qpcache.c
index 67f6a075f37a6ecb832d488bca597b556b8d0b4f..b8897141adb59565996de0f158adb5c392e1a2e0 100644 (file)
--- a/lib/dns/qpcache.c
+++ b/lib/dns/qpcache.c
@@ -1315,6 +1315,36 @@ check_stale_header(qpcnode_t *node, dns_slabheader_t *header,
        return true;
 }
 
+static bool
+related_headers(dns_slabheader_t *header, dns_typepair_t type,
+               dns_typepair_t sigtype, dns_typepair_t negtype,
+               dns_slabheader_t **foundp, dns_slabheader_t **foundsigp) {
+       if (!EXISTS(header) || ANCIENT(header)) {
+               return false;
+       }
+
+       if (header->type == type) {
+               *foundp = header;
+               if (*foundsigp != NULL) {
+                       return true;
+               }
+       } else if (header->type == sigtype) {
+               *foundsigp = header;
+               if (*foundp != NULL) {
+                       return true;
+               }
+
+       } else if (header->type == RDATATYPE_NCACHEANY ||
+                  header->type == negtype)
+       {
+               *foundp = header;
+               *foundsigp = NULL;
+               return true;
+       }
+
+       return false;
+}
+
 static bool
 both_headers(dns_slabheader_t *header, dns_rdatatype_t type,
             dns_slabheader_t **foundp, dns_slabheader_t **foundsigp) {
@@ -2119,12 +2149,14 @@ qpcache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
                     dns_rdataset_t *sigrdataset DNS__DB_FLARG) {
        qpcache_t *qpdb = (qpcache_t *)db;
        qpcnode_t *qpnode = (qpcnode_t *)node;
-       dns_slabheader_t *header = NULL, *header_next = NULL;
+       dns_slabheader_t *header = NULL;
+       dns_slabheader_t *header_prev = NULL, *header_next = NULL;
        dns_slabheader_t *found = NULL, *foundsig = NULL;
        dns_typepair_t matchtype, sigmatchtype, negtype;
        isc_result_t result;
        isc_rwlock_t *nlock = NULL;
        isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
+       qpc_search_t search;
 
        REQUIRE(VALID_QPDB(qpdb));
        REQUIRE(type != dns_rdatatype_any);
@@ -2137,6 +2169,11 @@ qpcache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
                now = isc_stdtime_now();
        }
 
+       search = (qpc_search_t){
+               .qpdb = (qpcache_t *)db,
+               .now = now,
+       };
+
        nlock = &qpdb->buckets[qpnode->locknum].lock;
        NODE_RDLOCK(nlock, &nlocktype);
 
@@ -2150,35 +2187,17 @@ qpcache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
 
        for (header = qpnode->data; header != NULL; header = header_next) {
                header_next = header->next;
-               if (!ACTIVE(header, now)) {
-                       if ((header->expire + STALE_TTL(header, qpdb) <
-                            now - QPDB_VIRTUAL) &&
-                           (nlocktype == isc_rwlocktype_write ||
-                            NODE_TRYUPGRADE(nlock, &nlocktype) ==
-                                    ISC_R_SUCCESS))
-                       {
-                               /*
-                                * We update the node's status only when we
-                                * can get write access.
-                                *
-                                * We don't check if refcurrent(qpnode) == 0
-                                * and try to free like we do in find(),
-                                * because refcurrent(qpnode) must be
-                                * non-zero.  This is so because 'node' is an
-                                * argument to the function.
-                                */
-                               mark_ancient(header);
-                       }
-               } else if (EXISTS(header) && !ANCIENT(header)) {
-                       if (header->type == matchtype) {
-                               found = header;
-                       } else if (header->type == RDATATYPE_NCACHEANY ||
-                                  header->type == negtype)
-                       {
-                               found = header;
-                       } else if (header->type == sigmatchtype) {
-                               foundsig = header;
-                       }
+
+               if (check_stale_header(qpnode, header, &nlocktype, nlock,
+                                      &search, &header_prev))
+               {
+                       continue;
+               }
+
+               if (related_headers(header, matchtype, sigmatchtype, negtype,
+                                   &found, &foundsig))
+               {
+                       break;
                }
        }
        if (found != NULL) {