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Code Issues Releases Wiki Activity

Clean up the search part in qpcache_find()

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Slightly refactor the header search in qpcache_find(), so the scope
level is reduced and the cname parts are logically grouped together.
This commit is contained in:
Ondřej Surý
2025-02-02 20:36:13 +01:00
committed by Evan Hunt
parent bfb219ac2d
commit 3b2fe808c4
1 changed files with 108 additions and 109 deletions
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217
lib/dns/qpcache.c
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@@ -1315,59 +1315,55 @@ check_stale_header(qpcnode_t *node, dns_slabheader_t *header,
return true;
}
/*
* Return true if we've found headers for both 'type' and RRSIG('type'),
* or (optionally, if 'negtype' is nonzero) if we've found a single
* negative header covering either 'negtype' or ANY.
*/
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) {
dns_slabheader_t **foundp, dns_slabheader_t **foundsigp,
bool *matchp) {
if (!EXISTS(header) || ANCIENT(header)) {
return false;
}
if (header->type == type) {
*foundp = header;
SET_IF_NOT_NULL(matchp, true);
if (*foundsigp != NULL) {
return true;
}
} else if (header->type == sigtype) {
*foundsigp = header;
SET_IF_NOT_NULL(matchp, true);
if (*foundp != NULL) {
return true;
}
} else if (header->type == RDATATYPE_NCACHEANY ||
header->type == negtype)
} else if (negtype != 0 && (header->type == RDATATYPE_NCACHEANY ||
header->type == negtype))
{
*foundp = header;
*foundsigp = NULL;
SET_IF_NOT_NULL(matchp, true);
return true;
}
return false;
}
/*
* Return true if we've found headers for both 'type' and RRSIG('type').
*/
static bool
both_headers(dns_slabheader_t *header, dns_rdatatype_t type,
dns_slabheader_t **foundp, dns_slabheader_t **foundsigp) {
dns_typepair_t matchtype = DNS_TYPEPAIR_VALUE(type, 0);
dns_typepair_t sigmatchtype = DNS_SIGTYPE(type);
if (!EXISTS(header) || ANCIENT(header)) {
return false;
}
if (header->type == matchtype) {
*foundp = header;
if (*foundsigp != NULL) {
return true;
}
} else if (header->type == sigmatchtype) {
*foundsigp = header;
if (*foundp != NULL) {
return true;
}
}
return false;
return related_headers(header, matchtype, sigmatchtype, 0, foundp,
foundsigp, NULL);
}
static isc_result_t
@@ -1599,6 +1595,15 @@ find_coveringnsec(qpc_search_t *search, const dns_name_t *name,
return result;
}
#define MISSING_ANSWER(found, options) \
((found) == NULL || \
(DNS_TRUST_ADDITIONAL((found)->trust) && \
(((options) & DNS_DBFIND_ADDITIONALOK) == 0)) || \
((found)->trust == dns_trust_glue && \
(((options) & DNS_DBFIND_GLUEOK) == 0)) || \
(DNS_TRUST_PENDING((found)->trust) && \
(((options) & DNS_DBFIND_PENDINGOK) == 0)))
static isc_result_t
qpcache_find(dns_db_t *db, const dns_name_t *name, dns_dbversion_t *version,
dns_rdatatype_t type, unsigned int options, isc_stdtime_t now,
@@ -1753,91 +1758,92 @@ qpcache_find(dns_db_t *db, const dns_name_t *name, dns_dbversion_t *version,
continue;
}
if (EXISTS(header) && !ANCIENT(header)) {
if (!EXISTS(header) || ANCIENT(header)) {
continue;
}
/*
* We now know that there is at least one active
* non-stale rdataset at this node.
*/
empty_node = false;
if (header->noqname != NULL &&
header->trust == dns_trust_secure)
{
found_noqname = true;
}
if (!NEGATIVE(header)) {
all_negative = false;
}
bool match = false;
if (related_headers(header, type, sigtype, negtype, &found,
&foundsig, &match) &&
!MISSING_ANSWER(found, options))
{
/*
* We now know that there is at least one active
* non-stale rdataset at this node.
* We can't exit early until we have an answer with
* sufficient trust level, see MISSING_ANSWER() macro
* for details, because we might need NS or NSEC
* records.
*/
empty_node = false;
if (header->noqname != NULL &&
header->trust == dns_trust_secure)
{
found_noqname = true;
}
if (!NEGATIVE(header)) {
all_negative = false;
break;
}
if (match) {
/* We found something, continue with next header */
continue;
}
switch (header->type) {
case dns_rdatatype_cname:
if (!cname_ok) {
break;
}
/*
* If we found a type we were looking for, remember
* it.
*/
if (header->type == type ||
(type == dns_rdatatype_any &&
DNS_TYPEPAIR_TYPE(header->type) != 0) ||
(cname_ok && header->type == dns_rdatatype_cname))
found = header;
if (cnamesig != NULL) {
/* We already have CNAME signature */
foundsig = cnamesig;
} else {
/* Look for CNAME signature instead */
sigtype = DNS_SIGTYPE(dns_rdatatype_cname);
foundsig = NULL;
}
break;
case DNS_SIGTYPE(dns_rdatatype_cname):
if (!cname_ok) {
break;
}
cnamesig = header;
break;
case dns_rdatatype_ns:
/* Remember the NS rdataset */
nsheader = header;
break;
case DNS_SIGTYPE(dns_rdatatype_ns):
/* ...and its signature */
nssig = header;
break;
case dns_rdatatype_nsec:
nsecheader = header;
break;
case DNS_SIGTYPE(dns_rdatatype_nsec):
nsecsig = header;
break;
default:
if (type == dns_rdatatype_any &&
DNS_TYPEPAIR_TYPE(header->type) != 0)
{
/*
* We've found the answer.
*/
/* QTYPE==ANY, so any anwers will do */
found = header;
if (header->type == dns_rdatatype_cname &&
cname_ok)
{
/*
* If we've already got the
* CNAME RRSIG, use it.
*/
if (cnamesig != NULL) {
foundsig = cnamesig;
} else {
sigtype = DNS_SIGTYPE(
dns_rdatatype_cname);
}
}
} else if (header->type == sigtype) {
/*
* We've found the RRSIG rdataset for our
* target type. Remember it.
*/
foundsig = header;
} else if (header->type == RDATATYPE_NCACHEANY ||
header->type == negtype)
{
/*
* We've found a negative cache entry.
*/
found = header;
} else if (header->type == dns_rdatatype_ns) {
/*
* Remember a NS rdataset even if we're
* not specifically looking for it, because
* we might need it later.
*/
nsheader = header;
} else if (header->type ==
DNS_SIGTYPE(dns_rdatatype_ns))
{
/*
* If we need the NS rdataset, we'll also
* need its signature.
*/
nssig = header;
} else if (header->type == dns_rdatatype_nsec) {
nsecheader = header;
} else if (header->type ==
DNS_SIGTYPE(dns_rdatatype_nsec))
{
nsecsig = header;
} else if (cname_ok &&
header->type ==
DNS_SIGTYPE(dns_rdatatype_cname))
{
/*
* If we get a CNAME match, we'll also need
* its signature.
*/
cnamesig = header;
break;
}
}
}
@@ -1863,14 +1869,7 @@ qpcache_find(dns_db_t *db, const dns_name_t *name, dns_dbversion_t *version,
/*
* If we didn't find what we were looking for...
*/
if (found == NULL ||
(DNS_TRUST_ADDITIONAL(found->trust) &&
((options & DNS_DBFIND_ADDITIONALOK) == 0)) ||
(found->trust == dns_trust_glue &&
((options & DNS_DBFIND_GLUEOK) == 0)) ||
(DNS_TRUST_PENDING(found->trust) &&
((options & DNS_DBFIND_PENDINGOK) == 0)))
{
if (MISSING_ANSWER(found, options)) {
/*
* Return covering NODATA NSEC record.
*/
@@ -2195,7 +2194,7 @@ qpcache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
}
if (related_headers(header, matchtype, sigmatchtype, negtype,
&found, &foundsig))
&found, &foundsig, NULL))
{
break;
}