mir/bind
2
0
Fork 0
mirror of https://gitlab.isc.org/isc-projects/bind9 synced 2025-08-31 06:25:31 +00:00
Code Issues Releases Wiki Activity

Separate prefetch handling from RPZ fetch handling

Browse Source 
Both prefetch code and RPZ code ignore recursion results (caching the
response notwithstanding).  RPZ code has been (ab)using that fact since
commit 08e36aa5a5 by employing
prefetch_done() as the fetch completion callback.  This is only
seemingly a simplification as it makes the code harder to follow ("why
is prefetch code used for handling RPZ-triggered recursion?").

Turn prefetch_done() into a new function whose name clearly conveys its
purpose.  Add a parameter to its prototype in order to allow callers to
specify which slot in the 'recursions' array it should use.  Reintroduce
prefetch_done() as a wrapper for that function.  Add rpzfetch_done(), an
RPZ-exclusive wrapper for that function (using a distinct recursion
type).

Since each slot in the 'recursions' array needs to be initialized before
getting cleaned up when recursion completes, rework fetch_and_forget()
so that it takes recursion type rather than extra fetch options as the
last parameter and make it use the requested slot in the 'recursions'
array rather than a fixed slot (RECTYPE_PREFETCH) for all callers.  This
makes fetch_and_forget() a logical complement of cleanup_after_fetch().

Collectively, these changes make prefetch and RPZ code logically
separate (except for reusing client->recursionquota, which will be
refactored later).
This commit is contained in:
Michał Kępień
2022-06-14 13:13:32 +02:00
parent 30ace0663d
commit 9eaddf2e4f
1 changed files with 59 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

87
lib/ns/query.c
View File

@@ -2511,8 +2511,11 @@ recursionquota_detach(ns_client_t *client) {
}
static void
prefetch_done(isc_task_t *task, isc_event_t *event) {
cleanup_after_fetch(isc_task_t *task, isc_event_t *event,
ns_query_rectype_t recursion_type) {
dns_fetchevent_t *devent = (dns_fetchevent_t *)event;
isc_nmhandle_t **handlep;
dns_fetch_t **fetchp;
ns_client_t *client;
UNUSED(task);
@@ -2524,37 +2527,50 @@ prefetch_done(isc_task_t *task, isc_event_t *event) {
CTRACE(ISC_LOG_DEBUG(3), "prefetch_done");
handlep = &client->query.recursions[recursion_type].handle;
fetchp = &client->query.recursions[recursion_type].fetch;
LOCK(&client->query.fetchlock);
if (FETCH_RECTYPE_PREFETCH(client) != NULL) {
INSIST(devent->fetch == FETCH_RECTYPE_PREFETCH(client));
FETCH_RECTYPE_PREFETCH(client) = NULL;
if (*fetchp != NULL) {
INSIST(devent->fetch == *fetchp);
*fetchp = NULL;
}
UNLOCK(&client->query.fetchlock);
/*
* We're done prefetching, detach from quota.
*/
recursionquota_detach(client);
free_devent(client, &event, &devent);
isc_nmhandle_detach(&HANDLE_RECTYPE_PREFETCH(client));
isc_nmhandle_detach(handlep);
}
static void
prefetch_done(isc_task_t *task, isc_event_t *event) {
cleanup_after_fetch(task, event, RECTYPE_PREFETCH);
}
static void
rpzfetch_done(isc_task_t *task, isc_event_t *event) {
cleanup_after_fetch(task, event, RECTYPE_RPZ);
}
/*
* Try initiating a fetch for the given 'qname' and 'qtype' (with any requested
* 'extra_fetch_options') that will be associated with 'client'. If the
* recursive clients quota (or even soft quota) is reached or some other error
* occurs, just return without starting the fetch. If a fetch is successfully
* created, its results will be cached upon successful completion, but no
* further actions will be taken afterwards.
* Try initiating a fetch for the given 'qname' and 'qtype' (using the slot in
* the 'recursions' array indicated by 'recursion_type') that will be
* associated with 'client'. If the recursive clients quota (or even soft
* quota) is reached or some other error occurs, just return without starting
* the fetch. If a fetch is successfully created, its results will be cached
* upon successful completion, but no further actions will be taken afterwards.
*/
static void
fetch_and_forget(ns_client_t *client, dns_name_t *qname, dns_rdatatype_t qtype,
unsigned int extra_fetch_options) {
isc_result_t result;
isc_sockaddr_t *peeraddr;
ns_query_rectype_t recursion_type) {
dns_rdataset_t *tmprdataset;
isc_sockaddr_t *peeraddr;
unsigned int options;
isc_taskaction_t action;
isc_nmhandle_t **handlep;
dns_fetch_t **fetchp;
isc_result_t result;
result = recursionquota_attach_hard(client);
if (result != ISC_R_SUCCESS) {
@@ -2569,16 +2585,31 @@ fetch_and_forget(ns_client_t *client, dns_name_t *qname, dns_rdatatype_t qtype,
peeraddr = NULL;
}
isc_nmhandle_attach(client->handle, &HANDLE_RECTYPE_PREFETCH(client));
options = client->query.fetchoptions | extra_fetch_options;
result = dns_resolver_createfetch(
client->view->resolver, qname, qtype, NULL, NULL, NULL,
peeraddr, client->message->id, options, 0, NULL,
client->manager->task, prefetch_done, client, tmprdataset, NULL,
&FETCH_RECTYPE_PREFETCH(client));
switch (recursion_type) {
case RECTYPE_PREFETCH:
options = client->query.fetchoptions | DNS_FETCHOPT_PREFETCH;
action = prefetch_done;
break;
case RECTYPE_RPZ:
options = client->query.fetchoptions;
action = rpzfetch_done;
break;
default:
UNREACHABLE();
}
handlep = &client->query.recursions[recursion_type].handle;
fetchp = &client->query.recursions[recursion_type].fetch;
isc_nmhandle_attach(client->handle, handlep);
result = dns_resolver_createfetch(client->view->resolver, qname, qtype,
NULL, NULL, NULL, peeraddr,
client->message->id, options, 0, NULL,
client->manager->task, action, client,
tmprdataset, NULL, fetchp);
if (result != ISC_R_SUCCESS) {
ns_client_putrdataset(client, &tmprdataset);
isc_nmhandle_detach(&HANDLE_RECTYPE_PREFETCH(client));
isc_nmhandle_detach(handlep);
}
}
@@ -2595,7 +2626,7 @@ query_prefetch(ns_client_t *client, dns_name_t *qname,
return;
}
fetch_and_forget(client, qname, rdataset->type, DNS_FETCHOPT_PREFETCH);
fetch_and_forget(client, qname, rdataset->type, RECTYPE_PREFETCH);
dns_rdataset_clearprefetch(rdataset);
ns_stats_increment(client->manager->sctx->nsstats,
@@ -2762,11 +2793,11 @@ static void
query_rpzfetch(ns_client_t *client, dns_name_t *qname, dns_rdatatype_t type) {
CTRACE(ISC_LOG_DEBUG(3), "query_rpzfetch");
if (FETCH_RECTYPE_PREFETCH(client) != NULL) {
if (FETCH_RECTYPE_RPZ(client) != NULL) {
return;
}
fetch_and_forget(client, qname, type, 0);
fetch_and_forget(client, qname, type, RECTYPE_RPZ);
}
/*