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fix: dev: Remove 'target' from dns_adb

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When a server name turns out to be a CNAME or DNAME, the ADB does not use it, but the `dns_adbname` structure still stored a copy of the target name. This is unnecessary and the code has been removed.

Merge branch 'each-remove-adb-target' into 'main'

See merge request isc-projects/bind9!10149
This commit is contained in:
Evan Hunt 2025-02-26 00:43:46 +00:00
commit 764eb65cf6
4 changed files with 26 additions and 138 deletions
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147
lib/dns/adb.c
View file

@ -137,8 +137,6 @@ struct dns_adbname {
dns_name_t *name;
unsigned int partial_result;
unsigned int flags;
dns_name_t target;
isc_stdtime_t expire_target;
isc_stdtime_t expire_v4;
isc_stdtime_t expire_v6;
dns_adbnamehooklist_t v4;
@ -314,8 +312,6 @@ print_fetch_list(FILE *, dns_adbname_t *);
static void
clean_namehooks(dns_adb_t *, dns_adbnamehooklist_t *);
static void
clean_target(dns_adb_t *, dns_name_t *);
static void
clean_finds_at_name(dns_adbname_t *, dns_adbstatus_t, unsigned int);
static void
maybe_expire_namehooks(dns_adbname_t *, isc_stdtime_t);
@ -369,8 +365,10 @@ enum {
*/
enum {
NAME_IS_DEAD = 1 << 31,
NAME_IS_ALIAS = 1 << 30,
};
#define NAME_DEAD(n) (((n)->flags & NAME_IS_DEAD) != 0)
#define NAME_DEAD(n) (((n)->flags & NAME_IS_DEAD) != 0)
#define NAME_ALIAS(n) (((n)->flags & NAME_IS_ALIAS) != 0)
/*
* Private flag(s) for adbentry objects. Note that these will also
@ -674,7 +672,6 @@ expire_name(dns_adbname_t *adbname, dns_adbstatus_t astat) {
clean_finds_at_name(adbname, astat, DNS_ADBFIND_ADDRESSMASK);
clean_namehooks(adb, &adbname->v4);
clean_namehooks(adb, &adbname->v6);
clean_target(adb, &adbname->target);
if (NAME_FETCH_A(adbname)) {
dns_resolver_cancelfetch(adbname->fetch_a->fetch);
@ -733,14 +730,6 @@ maybe_expire_namehooks(dns_adbname_t *adbname, isc_stdtime_t now) {
adbname->expire_v6 = INT_MAX;
adbname->fetch6_err = FIND_ERR_UNEXPECTED;
}
/*
* Check to see if we need to remove the alias target.
*/
if (EXPIRE_OK(adbname->expire_target, now)) {
clean_target(adb, &adbname->target);
adbname->expire_target = INT_MAX;
}
}
static void
@ -811,81 +800,6 @@ clean_namehooks(dns_adb_t *adb, dns_adbnamehooklist_t *namehooks) {
}
}
static void
clean_target(dns_adb_t *adb, dns_name_t *target) {
if (dns_name_countlabels(target) > 0) {
dns_name_free(target, adb->mctx);
dns_name_init(target);
}
}
static isc_result_t
set_target(dns_adb_t *adb, const dns_name_t *name, const dns_name_t *fname,
dns_rdataset_t *rdataset, dns_name_t *target) {
isc_result_t result;
dns_rdata_t rdata = DNS_RDATA_INIT;
REQUIRE(dns_name_countlabels(target) == 0);
if (rdataset->type == dns_rdatatype_cname) {
dns_rdata_cname_t cname;
/*
* Copy the CNAME's target into the target name.
*/
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS) {
return result;
}
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_tostruct(&rdata, &cname, NULL);
if (result != ISC_R_SUCCESS) {
return result;
}
dns_name_dup(&cname.cname, adb->mctx, target);
dns_rdata_freestruct(&cname);
} else {
dns_fixedname_t fixed1, fixed2;
dns_name_t *prefix = NULL, *new_target = NULL;
dns_rdata_dname_t dname;
dns_namereln_t namereln;
unsigned int nlabels;
int order;
INSIST(rdataset->type == dns_rdatatype_dname);
namereln = dns_name_fullcompare(name, fname, &order, &nlabels);
INSIST(namereln == dns_namereln_subdomain);
/*
* Get the target name of the DNAME.
*/
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS) {
return result;
}
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_tostruct(&rdata, &dname, NULL);
if (result != ISC_R_SUCCESS) {
return result;
}
/*
* Construct the new target name.
*/
prefix = dns_fixedname_initname(&fixed1);
new_target = dns_fixedname_initname(&fixed2);
dns_name_split(name, nlabels, prefix, NULL);
result = dns_name_concatenate(prefix, &dname.dname, new_target);
dns_rdata_freestruct(&dname);
if (result != ISC_R_SUCCESS) {
return result;
}
dns_name_dup(new_target, adb->mctx, target);
}
return ISC_R_SUCCESS;
}
/*
* The name must be locked.
*/
@ -966,7 +880,6 @@ new_adbname(dns_adb_t *adb, const dns_name_t *dnsname, unsigned int flags) {
.adb = dns_adb_ref(adb),
.expire_v4 = INT_MAX,
.expire_v6 = INT_MAX,
.expire_target = INT_MAX,
.fetch_err = FIND_ERR_UNEXPECTED,
.fetch6_err = FIND_ERR_UNEXPECTED,
.v4 = ISC_LIST_INITIALIZER,
@ -987,7 +900,6 @@ new_adbname(dns_adb_t *adb, const dns_name_t *dnsname, unsigned int flags) {
name->name = dns_fixedname_initname(&name->fname);
dns_name_copy(dnsname, name->name);
dns_name_init(&name->target);
inc_adbstats(adb, dns_adbstats_namescnt);
return name;
@ -1544,8 +1456,7 @@ maybe_expire_name(dns_adbname_t *adbname, isc_stdtime_t now) {
/* ... or is not yet expired. */
if (!EXPIRE_OK(adbname->expire_v4, now) ||
!EXPIRE_OK(adbname->expire_v6, now) ||
!EXPIRE_OK(adbname->expire_target, now))
!EXPIRE_OK(adbname->expire_v6, now))
{
return false;
}
@ -1926,8 +1837,8 @@ isc_result_t
dns_adb_createfind(dns_adb_t *adb, isc_loop_t *loop, isc_job_cb cb, void *cbarg,
const dns_name_t *name, const dns_name_t *qname,
dns_rdatatype_t qtype ISC_ATTR_UNUSED, unsigned int options,
isc_stdtime_t now, dns_name_t *target, in_port_t port,
unsigned int depth, isc_counter_t *qc, isc_counter_t *gqc,
isc_stdtime_t now, in_port_t port, unsigned int depth,
isc_counter_t *qc, isc_counter_t *gqc,
dns_adbfind_t **findp) {
isc_result_t result = ISC_R_UNEXPECTED;
dns_adbfind_t *find = NULL;
@ -1948,7 +1859,6 @@ dns_adb_createfind(dns_adb_t *adb, isc_loop_t *loop, isc_job_cb cb, void *cbarg,
REQUIRE(name != NULL);
REQUIRE(qname != NULL);
REQUIRE(findp != NULL && *findp == NULL);
REQUIRE(target == NULL || dns_name_hasbuffer(target));
REQUIRE((options & DNS_ADBFIND_ADDRESSMASK) != 0);
@ -2004,7 +1914,7 @@ again:
/*
* Do we know that the name is an alias?
*/
if (!EXPIRE_OK(adbname->expire_target, now)) {
if (NAME_ALIAS(adbname) && !EXPIRE_OK(adbname->expire_v4, now)) {
/* Yes, it is. */
DP(DEF_LEVEL,
"dns_adb_createfind: name %s (%p) is an alias (cached)",
@ -2218,9 +2128,6 @@ post_copy:
find->partial_result |= (adbname->partial_result & wanted_addresses);
if (alias) {
if (target != NULL) {
dns_name_copy(&adbname->target, target);
}
result = DNS_R_ALIAS;
} else {
result = ISC_R_SUCCESS;
@ -2408,14 +2315,9 @@ dump_adb(dns_adb_t *adb, FILE *f, bool debug, isc_stdtime_t now) {
}
fprintf(f, "; ");
dns_name_print(name->name, f);
if (dns_name_countlabels(&name->target) > 0) {
fprintf(f, " alias ");
dns_name_print(&name->target, f);
}
dump_ttl(f, "v4", name->expire_v4, now);
dump_ttl(f, "v6", name->expire_v6, now);
dump_ttl(f, "target", name->expire_target, now);
fprintf(f, " [v4 %s] [v6 %s]", errnames[name->fetch_err],
errnames[name->fetch6_err]);
@ -2762,18 +2664,17 @@ dbfind_name(dns_adbname_t *adbname, isc_stdtime_t now, dns_rdatatype_t rdtype) {
break;
case DNS_R_CNAME:
case DNS_R_DNAME:
/*
* We found a CNAME or DNAME. Mark this as an
* alias (not to be used) and mark the expiry
* for both address families so we won't ask again
* for a while.
*/
rdataset.ttl = ttlclamp(rdataset.ttl);
clean_target(adb, &adbname->target);
adbname->expire_target = INT_MAX;
result = set_target(adb, adbname->name, fname, &rdataset,
&adbname->target);
if (result == ISC_R_SUCCESS) {
result = DNS_R_ALIAS;
DP(NCACHE_LEVEL, "adb name %p: caching alias target",
adbname);
adbname->expire_target = ADJUSTED_EXPIRE(
adbname->expire_target, now, rdataset.ttl);
}
result = DNS_R_ALIAS;
adbname->flags |= NAME_IS_ALIAS;
adbname->expire_v4 = adbname->expire_v6 =
ADJUSTED_EXPIRE(INT_MAX, now, rdataset.ttl);
if (rdtype == dns_rdatatype_a) {
adbname->fetch_err = FIND_ERR_SUCCESS;
} else {
@ -2888,16 +2789,10 @@ fetch_callback(void *arg) {
*/
if (resp->result == DNS_R_CNAME || resp->result == DNS_R_DNAME) {
resp->rdataset->ttl = ttlclamp(resp->rdataset->ttl);
clean_target(adb, &name->target);
name->expire_target = INT_MAX;
result = set_target(adb, name->name, resp->foundname,
resp->rdataset, &name->target);
if (result == ISC_R_SUCCESS) {
DP(NCACHE_LEVEL,
"adb fetch name %p: caching alias target", name);
name->expire_target = ADJUSTED_EXPIRE(
name->expire_target, now, resp->rdataset->ttl);
}
result = ISC_R_SUCCESS;
name->flags |= NAME_IS_ALIAS;
name->expire_v4 = name->expire_v6 =
ADJUSTED_EXPIRE(INT_MAX, now, resp->rdataset->ttl);
goto check_result;
}

11
lib/dns/include/dns/adb.h
View file

@ -278,9 +278,8 @@ isc_result_t
dns_adb_createfind(dns_adb_t *adb, isc_loop_t *loop, isc_job_cb cb, void *cbarg,
const dns_name_t *name, const dns_name_t *qname,
dns_rdatatype_t qtype, unsigned int options,
isc_stdtime_t now, dns_name_t *target, in_port_t port,
unsigned int depth, isc_counter_t *qc, isc_counter_t *gqc,
dns_adbfind_t **find);
isc_stdtime_t now, in_port_t port, unsigned int depth,
isc_counter_t *qc, isc_counter_t *gqc, dns_adbfind_t **find);
/*%<
* Main interface for clients. The adb will look up the name given in
* "name" and will build up a list of found addresses, and perhaps start
@ -313,10 +312,6 @@ dns_adb_createfind(dns_adb_t *adb, isc_loop_t *loop, isc_job_cb cb, void *cbarg,
* the running database. If specified as zero, the current time will
* be retrieved and used.
*
* If 'target' is not NULL and 'name' is an alias (i.e. the name is
* CNAME'd or DNAME'd to another name), then 'target' will be updated with
* the domain name that 'name' is aliased to.
*
* All addresses returned will have the sockaddr's port set to 'port.'
* The caller may change them directly in the dns_adbaddrinfo_t since
* they are copies of the internal address only.
@ -332,8 +327,6 @@ dns_adb_createfind(dns_adb_t *adb, isc_loop_t *loop, isc_job_cb cb, void *cbarg,
*
*\li qname != NULL and *qname be a valid dns_name_t.
*
*\li target == NULL or target is a valid name with a buffer.
*
*\li find != NULL && *find == NULL.
*
* Returns:

2
lib/dns/resolver.c
View file

@ -3301,7 +3301,7 @@ findname(fetchctx_t *fctx, const dns_name_t *name, in_port_t port,
fetchctx_ref(fctx);
result = dns_adb_createfind(fctx->adb, fctx->loop, fctx_finddone, fctx,
name, fctx->name, fctx->type, options, now,
NULL, res->view->dstport, fctx->depth + 1,
res->view->dstport, fctx->depth + 1,
fctx->qc, fctx->gqc, &find);
isc_log_write(DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER,

4
lib/dns/zone.c
View file

@ -12587,7 +12587,7 @@ notify_find_address(dns_notify_t *notify) {
result = dns_adb_createfind(
adb, notify->zone->loop, process_notify_adb_event, notify,
&notify->ns, dns_rootname, 0, options, 0, NULL,
&notify->ns, dns_rootname, 0, options, 0,
notify->zone->view->dstport, 0, NULL, NULL, &notify->find);
dns_adb_detach(&adb);
@ -21380,7 +21380,7 @@ checkds_find_address(dns_checkds_t *checkds) {
result = dns_adb_createfind(
adb, checkds->zone->loop, process_checkds_adb_event, checkds,
&checkds->ns, dns_rootname, 0, options, 0, NULL,
&checkds->ns, dns_rootname, 0, options, 0,
checkds->zone->view->dstport, 0, NULL, NULL, &checkds->find);
dns_adb_detach(&adb);