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Code Issues Releases Wiki Activity

Reuse recursion type code for refresh stale RRset

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Refreshing a stale RRset is similar to prefetching an RRset, so
reuse the existing code. When refreshing an RRset we need to clear
all db options related to serve-stale so that stale RRsets in cache
are ignored during the refresh.

We no longer need to set the "nodetach" flag, because the refresh
fetch is now a "fetch and forget". So we can detach from the client
in the query_send().

This code will break some serve-stale test cases, this will be fixed
in the successor commit.

TODO: add explanation why the serve-stale test cases fail.
This commit is contained in:
Matthijs Mekking
2022-09-29 09:57:46 +02:00
parent 5fb8e555bc
commit 64d51285d5
1 changed files with 24 additions and 86 deletions
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110
lib/ns/query.c
View File

@@ -2543,6 +2543,7 @@ cleanup_after_fetch(isc_task_t *task, isc_event_t *event, const char *ctracestr,
fetchp = &client->query.recursions[recursion_type].fetch;
LOCK(&client->query.fetchlock);
if (*fetchp != NULL) {
INSIST(devent->fetch == *fetchp);
*fetchp = NULL;
@@ -2550,7 +2551,6 @@ cleanup_after_fetch(isc_task_t *task, isc_event_t *event, const char *ctracestr,
UNLOCK(&client->query.fetchlock);
recursionquotatype_detach(client, recursion_type);
free_devent(client, &event, &devent);
isc_nmhandle_detach(handlep);
}
@@ -2566,8 +2566,9 @@ rpzfetch_done(isc_task_t *task, isc_event_t *event) {
}
static void
refresh_done(isc_task_t *task, isc_event_t *event) {
cleanup_after_fetch(task, event, "refresh_done", RECTYPE_REFRESH);
stale_refresh_done(isc_task_t *task, isc_event_t *event) {
cleanup_after_fetch(task, event, "stale_refresh_done",
RECTYPE_STALE_REFRESH);
}
/*
@@ -2611,9 +2612,9 @@ fetch_and_forget(ns_client_t *client, dns_name_t *qname, dns_rdatatype_t qtype,
options = client->query.fetchoptions;
action = rpzfetch_done;
break;
case RECTYPE_REFRESH:
case RECTYPE_STALE_REFRESH:
options = client->query.fetchoptions;
action = refresh_done;
action = stale_refresh_done;
break;
default:
UNREACHABLE();
@@ -2655,19 +2656,29 @@ query_prefetch(ns_client_t *client, dns_name_t *qname,
ns_statscounter_prefetch);
}
/*
static void
query_refresh(ns_client_t *client, dns_name_t *qname,
dns_rdataset_t *rdataset) {
CTRACE(ISC_LOG_DEBUG(3), "query_refresh");
query_stale_refresh(ns_client_t *client) {
dns_name_t *qname;
if (FETCH_RECTYPE_REFRESH(client) != NULL) {
CTRACE(ISC_LOG_DEBUG(3), "query_stale_refresh");
if (FETCH_RECTYPE_STALE_REFRESH(client) != NULL) {
return;
}
fetch_and_forget(client, qname, rdataset->type, RECTYPE_REFRESH);
client->query.dboptions &= ~(DNS_DBFIND_STALETIMEOUT |
DNS_DBFIND_STALEOK |
DNS_DBFIND_STALEENABLED);
if (client->query.origqname != NULL) {
qname = client->query.origqname;
} else {
qname = client->query.qname;
}
fetch_and_forget(client, qname, client->query.qtype,
RECTYPE_STALE_REFRESH);
}
*/
static void
rpz_clean(dns_zone_t **zonep, dns_db_t **dbp, dns_dbnode_t **nodep,
@@ -5225,26 +5236,6 @@ qctx_init(ns_client_t *client, dns_fetchevent_t **eventp, dns_rdatatype_t qtype,
CALL_HOOK_NORETURN(NS_QUERY_QCTX_INITIALIZED, qctx);
}
/*
* Make 'dst' and exact copy of 'src', with exception of the
* option field, which is reset to zero.
* This function also attaches dst's view and db to the src's
* view and cachedb.
*/
static void
qctx_copy(const query_ctx_t *qctx, query_ctx_t *dst) {
REQUIRE(qctx != NULL);
REQUIRE(dst != NULL);
memmove(dst, qctx, sizeof(*dst));
dst->view = NULL;
dst->db = NULL;
dst->options = 0;
dns_view_attach(qctx->view, &dst->view);
dns_db_attach(qctx->view->cachedb, &dst->db);
CCTRACE(ISC_LOG_DEBUG(3), "qctx_copy");
}
/*%
* Clean up and disassociate the rdataset and node pointers in qctx.
*/
@@ -5749,54 +5740,6 @@ qctx_prepare_buffers(query_ctx_t *qctx, isc_buffer_t *buffer) {
return (ISC_R_SUCCESS);
}
/*
* Setup a new query context for resolving a query.
*
* This function is only called if both these conditions are met:
* 1. BIND is configured with stale-answer-client-timeout 0.
* 2. A stale RRset is found in cache during initial query
* database lookup.
*
* We continue with this function for refreshing/resolving an RRset
* after answering a client with stale data.
*/
static void
query_refresh_rrset(query_ctx_t *orig_qctx) {
isc_buffer_t buffer;
query_ctx_t qctx;
REQUIRE(orig_qctx != NULL);
REQUIRE(orig_qctx->client != NULL);
qctx_copy(orig_qctx, &qctx);
qctx.client->query.dboptions &= ~(DNS_DBFIND_STALETIMEOUT |
DNS_DBFIND_STALEOK |
DNS_DBFIND_STALEENABLED);
/*
* We'll need some resources...
*/
if (qctx_prepare_buffers(&qctx, &buffer) != ISC_R_SUCCESS) {
dns_db_detach(&qctx.db);
qctx_destroy(&qctx);
return;
}
/*
* Pretend we didn't find anything in cache.
*/
(void)query_gotanswer(&qctx, ISC_R_NOTFOUND);
if (qctx.fname != NULL) {
ns_client_releasename(qctx.client, &qctx.fname);
}
if (qctx.rdataset != NULL) {
ns_client_putrdataset(qctx.client, &qctx.rdataset);
}
qctx_destroy(&qctx);
}
/*%
* Perform a local database lookup, in either an authoritative or
* cache database. If unable to answer, call ns_query_done(); otherwise
@@ -11548,12 +11491,7 @@ ns_query_done(query_ctx_t *qctx) {
/*
* Client may have been detached after query_send(), so
* we test and store the flag state here, for safety.
* If we are refreshing the RRSet, we must not detach from the client
* in the query_send(), so we need to override the flag.
*/
if (qctx->refresh_rrset) {
qctx->client->nodetach = true;
}
nodetach = qctx->client->nodetach;
query_send(qctx->client);
@@ -11568,7 +11506,7 @@ ns_query_done(query_ctx_t *qctx) {
* refresh.
*/
message_clearrdataset(qctx->client->message, 0);
query_refresh_rrset(qctx);
query_stale_refresh(qctx->client);
}
if (!nodetach) {