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Add a mechanism to record namespaces for synth-from-dnssec

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When namespace is grafted on, the DNSSEC proofs for non existance
need to come from that namespace and not a higher namespace.  We
add 3 function dns_view_sfd_add, dns_view_sfd_del and dns_view_sfd_find
to add, remove and find the namespace that should be used when
checking NSEC records.

dns_view_sfd_add adds a name to a tree, creating the tree if needed.
If the name already existed in the tree the reference count is
increased otherwise it is initalised to 1.

dns_view_sfd_del removes a reference to a name in the tree, if the
count goes to 0 the node is removed.

dns_view_sfd_find returns the namespace to be used to entered name.
If there isn't an enclosing name in the tree, or the tree does not
yet exist, the root name is returned.

Access to the tree is controlled by a read/write lock.
This commit is contained in:
Mark Andrews 2022-06-16 16:31:10 +10:00
parent 788aa4b12f
commit 3619cad141
2 changed files with 120 additions and 0 deletions
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39
lib/dns/include/dns/view.h
View file

@ -144,6 +144,8 @@ struct dns_view {
dns_rbt_t *denyanswernames;
dns_rbt_t *answernames_exclude;
dns_rrl_t *rrl;
dns_rbt_t *sfd;
isc_rwlock_t sfd_lock;
bool provideixfr;
bool requestnsid;
bool sendcookie;
@ -1282,4 +1284,41 @@ dns_view_flushonshutdown(dns_view_t *view, bool flush);
* Requires:
*\li 'view' to be valid.
*/
void
dns_view_sfd_add(dns_view_t *view, const dns_name_t *name);
/*%<
* Add 'name' to the synth-from-dnssec namespace tree for the
* view. If the tree does not already exist create it.
*
* Requires:
*\li 'view' to be valid.
*\li 'name' to be valid.
*/
void
dns_view_sfd_del(dns_view_t *view, const dns_name_t *name);
/*%<
* Delete 'name' to the synth-from-dnssec namespace tree for
* the view when the count of previous adds and deletes becomes
* zero.
*
* Requires:
*\li 'view' to be valid.
*\li 'name' to be valid.
*/
void
dns_view_sfd_find(dns_view_t *view, const dns_name_t *name,
dns_name_t *foundname);
/*%<
* Find the enclosing name to the synth-from-dnssec namespace tree for 'name'
* in the specified view.
*
* Requires:
*\li 'view' to be valid.
*\li 'name' to be valid.
*\li 'foundname' to be valid with a buffer sufficient to hold the name.
*/
ISC_LANG_ENDDECLS

81
lib/dns/view.c
View file

@ -127,6 +127,8 @@ dns_view_create(isc_mem_t *mctx, dns_rdataclass_t rdclass, const char *name,
isc_mutex_init(&view->lock);
isc_rwlock_init(&view->sfd_lock, 0, 0);
view->zonetable = NULL;
result = dns_zt_create(mctx, rdclass, &view->zonetable);
if (result != ISC_R_SUCCESS) {
@ -215,6 +217,7 @@ cleanup_zt:
}
cleanup_mutex:
isc_rwlock_destroy(&view->sfd_lock);
isc_mutex_destroy(&view->lock);
if (view->nta_file != NULL) {
@ -381,6 +384,9 @@ destroy(dns_view_t *view) {
if (view->answernames_exclude != NULL) {
dns_rbt_destroy(&view->answernames_exclude);
}
if (view->sfd != NULL) {
dns_rbt_destroy(&view->sfd);
}
if (view->delonly != NULL) {
dns_name_t *name;
int i;
@ -464,6 +470,7 @@ destroy(dns_view_t *view) {
dns_badcache_destroy(&view->failcache);
}
isc_mutex_destroy(&view->new_zone_lock);
isc_rwlock_destroy(&view->sfd_lock);
isc_mutex_destroy(&view->lock);
isc_refcount_destroy(&view->references);
isc_refcount_destroy(&view->weakrefs);
@ -2334,3 +2341,77 @@ dns_view_flushonshutdown(dns_view_t *view, bool flush) {
view->flush = flush;
}
static void
free_sfd(void *data, void *arg) {
isc_mem_put(arg, data, sizeof(unsigned int));
}
void
dns_view_sfd_add(dns_view_t *view, const dns_name_t *name) {
isc_result_t result;
dns_rbtnode_t *node = NULL;
REQUIRE(DNS_VIEW_VALID(view));
RWLOCK(&view->sfd_lock, isc_rwlocktype_write);
if (view->sfd == NULL) {
result = dns_rbt_create(view->mctx, free_sfd, view->mctx,
&view->sfd);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
}
result = dns_rbt_addnode(view->sfd, name, &node);
RUNTIME_CHECK(result == ISC_R_SUCCESS || result == ISC_R_EXISTS);
if (node->data != NULL) {
unsigned int *count = node->data;
(*count)++;
} else {
unsigned int *count = isc_mem_get(view->mctx,
sizeof(unsigned int));
*count = 1;
node->data = count;
}
RWUNLOCK(&view->sfd_lock, isc_rwlocktype_write);
}
void
dns_view_sfd_del(dns_view_t *view, const dns_name_t *name) {
isc_result_t result;
void *data = NULL;
REQUIRE(DNS_VIEW_VALID(view));
RWLOCK(&view->sfd_lock, isc_rwlocktype_write);
INSIST(view->sfd != NULL);
result = dns_rbt_findname(view->sfd, name, 0, NULL, &data);
if (result == ISC_R_SUCCESS) {
unsigned int *count = data;
INSIST(count != NULL);
if (--(*count) == 0U) {
result = dns_rbt_deletename(view->sfd, name, false);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
}
}
RWUNLOCK(&view->sfd_lock, isc_rwlocktype_write);
}
void
dns_view_sfd_find(dns_view_t *view, const dns_name_t *name,
dns_name_t *foundname) {
REQUIRE(DNS_VIEW_VALID(view));
if (view->sfd != NULL) {
isc_result_t result;
void *data = NULL;
RWLOCK(&view->sfd_lock, isc_rwlocktype_read);
result = dns_rbt_findname(view->sfd, name, 0, foundname, &data);
RWUNLOCK(&view->sfd_lock, isc_rwlocktype_read);
if (result != ISC_R_SUCCESS && result != DNS_R_PARTIALMATCH) {
dns_name_copy(dns_rootname, foundname);
}
} else {
dns_name_copy(dns_rootname, foundname);
}
}