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Code Issues Releases Wiki Activity

Skip some QNAME mininisation queries if possible

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If we know that the NS RRset for an intermediate label doesn't exist
on cache contents don't query using that name when looking for a
referral.
This commit is contained in:
Mark Andrews 2023-05-23 14:02:29 +10:00
parent dd00b3c50b
commit 80bc0ee075
1 changed files with 48 additions and 31 deletions
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79
lib/dns/resolver.c
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@ -647,7 +647,7 @@ static void
fctx_try(fetchctx_t *fctx, bool retrying, bool badcache);
static void
fctx_shutdown(fetchctx_t *fctx);
static isc_result_t
static void
fctx_minimize_qname(fetchctx_t *fctx);
static void
fctx_destroy(fetchctx_t *fctx);
@ -4214,10 +4214,7 @@ resume_qmin(void *arg) {
fctx->ns_ttl = fctx->nameservers.ttl;
fctx->ns_ttl_ok = true;
result = fctx_minimize_qname(fctx);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
fctx_minimize_qname(fctx);
if (!fctx->minimized) {
/*
@ -4701,10 +4698,7 @@ fctx_create(dns_resolver_t *res, isc_loop_t *loop, const dns_name_t *name,
fctx->ip6arpaskip = (options & DNS_FETCHOPT_QMIN_SKIP_IP6A) !=
0 &&
dns_name_issubdomain(fctx->name, &ip6_arpa);
result = fctx_minimize_qname(fctx);
if (result != ISC_R_SUCCESS) {
goto cleanup_mctx;
}
fctx_minimize_qname(fctx);
}
nfctx = atomic_fetch_add_relaxed(&res->nfctx, 1);
@ -4718,11 +4712,6 @@ fctx_create(dns_resolver_t *res, isc_loop_t *loop, const dns_name_t *name,
return (ISC_R_SUCCESS);
cleanup_mctx:
fctx->magic = 0;
dns_adb_detach(&fctx->adb);
dns_db_detach(&fctx->cache);
cleanup_timer:
isc_timer_destroy(&fctx->timer);
@ -9256,11 +9245,7 @@ rctx_referral(respctx_t *rctx) {
if ((fctx->options & DNS_FETCHOPT_QMINIMIZE) != 0) {
dns_name_copy(rctx->ns_name, fctx->qmindcname);
result = fctx_minimize_qname(fctx);
if (result != ISC_R_SUCCESS) {
rctx->result = result;
return (ISC_R_COMPLETE);
}
fctx_minimize_qname(fctx);
}
result = fcount_incr(fctx, true);
@ -10145,13 +10130,16 @@ log_fetch(const dns_name_t *name, dns_rdatatype_t type) {
typebuf);
}
static isc_result_t
static void
fctx_minimize_qname(fetchctx_t *fctx) {
isc_result_t result = ISC_R_SUCCESS;
isc_result_t result;
unsigned int dlabels, nlabels;
dns_name_t name;
REQUIRE(VALID_FCTX(fctx));
dns_name_init(&name, NULL);
dlabels = dns_name_countlabels(fctx->qmindcname);
nlabels = dns_name_countlabels(fctx->name);
@ -10190,19 +10178,50 @@ fctx_minimize_qname(fetchctx_t *fctx) {
}
if (fctx->qmin_labels < nlabels) {
/*
* We want to query for qmin_labels from fctx->name
*/
dns_fixedname_t fname;
dns_name_t *name = dns_fixedname_initname(&fname);
dns_name_split(fctx->name, fctx->qmin_labels, NULL, name);
dns_name_copy(name, fctx->qminname);
dns_rdataset_t rdataset;
dns_fixedname_t fixed;
dns_name_t *fname = dns_fixedname_initname(&fixed);
dns_rdataset_init(&rdataset);
do {
/*
* We want to query for qmin_labels from fctx->name.
*/
dns_name_split(fctx->name, fctx->qmin_labels, NULL,
&name);
/*
* Look to see if we have anything cached about NS
* RRsets at this name and if so skip this name and
* try with an additional label prepended.
*/
result = dns_db_find(fctx->cache, &name, NULL,
dns_rdatatype_ns, 0, 0, NULL,
fname, &rdataset, NULL);
if (dns_rdataset_isassociated(&rdataset)) {
dns_rdataset_disassociate(&rdataset);
}
switch (result) {
case ISC_R_SUCCESS:
case DNS_R_CNAME:
case DNS_R_DNAME:
case DNS_R_NCACHENXDOMAIN:
case DNS_R_NCACHENXRRSET:
fctx->qmin_labels++;
continue;
default:
break;
}
break;
} while (fctx->qmin_labels < nlabels);
}
if (fctx->qmin_labels < nlabels) {
dns_name_copy(&name, fctx->qminname);
fctx->qmintype = dns_rdatatype_ns;
fctx->minimized = true;
} else {
/* Minimization is done, we'll ask for whole qname */
fctx->qmintype = fctx->type;
dns_name_copy(fctx->name, fctx->qminname);
fctx->qmintype = fctx->type;
fctx->minimized = false;
}
@ -10213,8 +10232,6 @@ fctx_minimize_qname(fetchctx_t *fctx) {
"QNAME minimization - %s minimized, qmintype %d "
"qminname %s",
fctx->minimized ? "" : "not", fctx->qmintype, domainbuf);
return (result);
}
static isc_result_t