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Refactor the search in qpcache_findrdataset()

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Add new related_headers() function that simplifies the code
flow in qpcache_findrdataset().  Also use check_stale_header() function
to remove code duplication.
This commit is contained in:
Ondřej Surý 2025-02-02 20:22:29 +01:00 committed by Evan Hunt
parent cf66ba02a4
commit bfb219ac2d
1 changed files with 49 additions and 30 deletions
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79
lib/dns/qpcache.c
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@ -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) {