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-rw-r--r--lib/dns/lookup.c450
1 files changed, 450 insertions, 0 deletions
diff --git a/lib/dns/lookup.c b/lib/dns/lookup.c
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+++ b/lib/dns/lookup.c
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+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <stdbool.h>
+
+#include <isc/mem.h>
+#include <isc/netaddr.h>
+#include <isc/string.h> /* Required for HP/UX (and others?) */
+#include <isc/task.h>
+#include <isc/util.h>
+
+#include <dns/db.h>
+#include <dns/events.h>
+#include <dns/lookup.h>
+#include <dns/rdata.h>
+#include <dns/rdataset.h>
+#include <dns/rdatastruct.h>
+#include <dns/resolver.h>
+#include <dns/result.h>
+#include <dns/view.h>
+
+struct dns_lookup {
+ /* Unlocked. */
+ unsigned int magic;
+ isc_mem_t *mctx;
+ isc_mutex_t lock;
+ dns_rdatatype_t type;
+ dns_fixedname_t name;
+ /* Locked by lock. */
+ unsigned int options;
+ isc_task_t *task;
+ dns_view_t *view;
+ dns_lookupevent_t *event;
+ dns_fetch_t *fetch;
+ unsigned int restarts;
+ bool canceled;
+ dns_rdataset_t rdataset;
+ dns_rdataset_t sigrdataset;
+};
+
+#define LOOKUP_MAGIC ISC_MAGIC('l', 'o', 'o', 'k')
+#define VALID_LOOKUP(l) ISC_MAGIC_VALID((l), LOOKUP_MAGIC)
+
+#define MAX_RESTARTS 16
+
+static void
+lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event);
+
+static void
+fetch_done(isc_task_t *task, isc_event_t *event) {
+ dns_lookup_t *lookup = event->ev_arg;
+ dns_fetchevent_t *fevent;
+
+ UNUSED(task);
+ REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
+ REQUIRE(VALID_LOOKUP(lookup));
+ REQUIRE(lookup->task == task);
+ fevent = (dns_fetchevent_t *)event;
+ REQUIRE(fevent->fetch == lookup->fetch);
+
+ lookup_find(lookup, fevent);
+}
+
+static isc_result_t
+start_fetch(dns_lookup_t *lookup) {
+ isc_result_t result;
+
+ /*
+ * The caller must be holding the lookup's lock.
+ */
+
+ REQUIRE(lookup->fetch == NULL);
+
+ result = dns_resolver_createfetch(
+ lookup->view->resolver, dns_fixedname_name(&lookup->name),
+ lookup->type, NULL, NULL, NULL, NULL, 0, 0, 0, NULL,
+ lookup->task, fetch_done, lookup, &lookup->rdataset,
+ &lookup->sigrdataset, &lookup->fetch);
+
+ return (result);
+}
+
+static isc_result_t
+build_event(dns_lookup_t *lookup) {
+ dns_name_t *name = NULL;
+ dns_rdataset_t *rdataset = NULL;
+ dns_rdataset_t *sigrdataset = NULL;
+
+ name = isc_mem_get(lookup->mctx, sizeof(dns_name_t));
+ dns_name_init(name, NULL);
+ dns_name_dup(dns_fixedname_name(&lookup->name), lookup->mctx, name);
+
+ if (dns_rdataset_isassociated(&lookup->rdataset)) {
+ rdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t));
+ dns_rdataset_init(rdataset);
+ dns_rdataset_clone(&lookup->rdataset, rdataset);
+ }
+
+ if (dns_rdataset_isassociated(&lookup->sigrdataset)) {
+ sigrdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t));
+ dns_rdataset_init(sigrdataset);
+ dns_rdataset_clone(&lookup->sigrdataset, sigrdataset);
+ }
+
+ lookup->event->name = name;
+ lookup->event->rdataset = rdataset;
+ lookup->event->sigrdataset = sigrdataset;
+
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+view_find(dns_lookup_t *lookup, dns_name_t *foundname) {
+ isc_result_t result;
+ dns_name_t *name = dns_fixedname_name(&lookup->name);
+ dns_rdatatype_t type;
+
+ if (lookup->type == dns_rdatatype_rrsig) {
+ type = dns_rdatatype_any;
+ } else {
+ type = lookup->type;
+ }
+
+ result = dns_view_find(lookup->view, name, type, 0, 0, false, false,
+ &lookup->event->db, &lookup->event->node,
+ foundname, &lookup->rdataset,
+ &lookup->sigrdataset);
+ return (result);
+}
+
+static void
+lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event) {
+ isc_result_t result;
+ bool want_restart;
+ bool send_event;
+ dns_name_t *name, *fname, *prefix;
+ dns_fixedname_t foundname, fixed;
+ dns_rdata_t rdata = DNS_RDATA_INIT;
+ unsigned int nlabels;
+ int order;
+ dns_namereln_t namereln;
+ dns_rdata_cname_t cname;
+ dns_rdata_dname_t dname;
+
+ REQUIRE(VALID_LOOKUP(lookup));
+
+ LOCK(&lookup->lock);
+
+ result = ISC_R_SUCCESS;
+ name = dns_fixedname_name(&lookup->name);
+
+ do {
+ lookup->restarts++;
+ want_restart = false;
+ send_event = true;
+
+ if (event == NULL && !lookup->canceled) {
+ fname = dns_fixedname_initname(&foundname);
+ INSIST(!dns_rdataset_isassociated(&lookup->rdataset));
+ INSIST(!dns_rdataset_isassociated(
+ &lookup->sigrdataset));
+ /*
+ * If we have restarted then clear the old node.
+ */
+ if (lookup->event->node != NULL) {
+ INSIST(lookup->event->db != NULL);
+ dns_db_detachnode(lookup->event->db,
+ &lookup->event->node);
+ }
+ if (lookup->event->db != NULL) {
+ dns_db_detach(&lookup->event->db);
+ }
+ result = view_find(lookup, fname);
+ if (result == ISC_R_NOTFOUND) {
+ /*
+ * We don't know anything about the name.
+ * Launch a fetch.
+ */
+ if (lookup->event->node != NULL) {
+ INSIST(lookup->event->db != NULL);
+ dns_db_detachnode(lookup->event->db,
+ &lookup->event->node);
+ }
+ if (lookup->event->db != NULL) {
+ dns_db_detach(&lookup->event->db);
+ }
+ result = start_fetch(lookup);
+ if (result == ISC_R_SUCCESS) {
+ send_event = false;
+ }
+ goto done;
+ }
+ } else if (event != NULL) {
+ result = event->result;
+ fname = dns_fixedname_name(&event->foundname);
+ dns_resolver_destroyfetch(&lookup->fetch);
+ INSIST(event->rdataset == &lookup->rdataset);
+ INSIST(event->sigrdataset == &lookup->sigrdataset);
+ } else {
+ fname = NULL; /* Silence compiler warning. */
+ }
+
+ /*
+ * If we've been canceled, forget about the result.
+ */
+ if (lookup->canceled) {
+ result = ISC_R_CANCELED;
+ }
+
+ switch (result) {
+ case ISC_R_SUCCESS:
+ result = build_event(lookup);
+ if (event == NULL) {
+ break;
+ }
+ if (event->db != NULL) {
+ dns_db_attach(event->db, &lookup->event->db);
+ }
+ if (event->node != NULL) {
+ dns_db_attachnode(lookup->event->db,
+ event->node,
+ &lookup->event->node);
+ }
+ break;
+ case DNS_R_CNAME:
+ /*
+ * Copy the CNAME's target into the lookup's
+ * query name and start over.
+ */
+ result = dns_rdataset_first(&lookup->rdataset);
+ if (result != ISC_R_SUCCESS) {
+ break;
+ }
+ dns_rdataset_current(&lookup->rdataset, &rdata);
+ result = dns_rdata_tostruct(&rdata, &cname, NULL);
+ dns_rdata_reset(&rdata);
+ if (result != ISC_R_SUCCESS) {
+ break;
+ }
+ dns_name_copynf(&cname.cname, name);
+ dns_rdata_freestruct(&cname);
+ want_restart = true;
+ send_event = false;
+ break;
+ case DNS_R_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(&lookup->rdataset);
+ if (result != ISC_R_SUCCESS) {
+ break;
+ }
+ dns_rdataset_current(&lookup->rdataset, &rdata);
+ result = dns_rdata_tostruct(&rdata, &dname, NULL);
+ dns_rdata_reset(&rdata);
+ if (result != ISC_R_SUCCESS) {
+ break;
+ }
+ /*
+ * Construct the new query name and start over.
+ */
+ prefix = dns_fixedname_initname(&fixed);
+ dns_name_split(name, nlabels, prefix, NULL);
+ result = dns_name_concatenate(prefix, &dname.dname,
+ name, NULL);
+ dns_rdata_freestruct(&dname);
+ if (result == ISC_R_SUCCESS) {
+ want_restart = true;
+ send_event = false;
+ }
+ break;
+ default:
+ send_event = true;
+ }
+
+ if (dns_rdataset_isassociated(&lookup->rdataset)) {
+ dns_rdataset_disassociate(&lookup->rdataset);
+ }
+ if (dns_rdataset_isassociated(&lookup->sigrdataset)) {
+ dns_rdataset_disassociate(&lookup->sigrdataset);
+ }
+
+ done:
+ if (event != NULL) {
+ if (event->node != NULL) {
+ dns_db_detachnode(event->db, &event->node);
+ }
+ if (event->db != NULL) {
+ dns_db_detach(&event->db);
+ }
+ isc_event_free(ISC_EVENT_PTR(&event));
+ }
+
+ /*
+ * Limit the number of restarts.
+ */
+ if (want_restart && lookup->restarts == MAX_RESTARTS) {
+ want_restart = false;
+ result = ISC_R_QUOTA;
+ send_event = true;
+ }
+ } while (want_restart);
+
+ if (send_event) {
+ lookup->event->result = result;
+ lookup->event->ev_sender = lookup;
+ isc_task_sendanddetach(&lookup->task,
+ (isc_event_t **)&lookup->event);
+ dns_view_detach(&lookup->view);
+ }
+
+ UNLOCK(&lookup->lock);
+}
+
+static void
+levent_destroy(isc_event_t *event) {
+ dns_lookupevent_t *levent;
+ isc_mem_t *mctx;
+
+ REQUIRE(event->ev_type == DNS_EVENT_LOOKUPDONE);
+ mctx = event->ev_destroy_arg;
+ levent = (dns_lookupevent_t *)event;
+
+ if (levent->name != NULL) {
+ if (dns_name_dynamic(levent->name)) {
+ dns_name_free(levent->name, mctx);
+ }
+ isc_mem_put(mctx, levent->name, sizeof(dns_name_t));
+ }
+ if (levent->rdataset != NULL) {
+ dns_rdataset_disassociate(levent->rdataset);
+ isc_mem_put(mctx, levent->rdataset, sizeof(dns_rdataset_t));
+ }
+ if (levent->sigrdataset != NULL) {
+ dns_rdataset_disassociate(levent->sigrdataset);
+ isc_mem_put(mctx, levent->sigrdataset, sizeof(dns_rdataset_t));
+ }
+ if (levent->node != NULL) {
+ dns_db_detachnode(levent->db, &levent->node);
+ }
+ if (levent->db != NULL) {
+ dns_db_detach(&levent->db);
+ }
+ isc_mem_put(mctx, event, event->ev_size);
+}
+
+isc_result_t
+dns_lookup_create(isc_mem_t *mctx, const dns_name_t *name, dns_rdatatype_t type,
+ dns_view_t *view, unsigned int options, isc_task_t *task,
+ isc_taskaction_t action, void *arg, dns_lookup_t **lookupp) {
+ dns_lookup_t *lookup;
+ isc_event_t *ievent;
+
+ lookup = isc_mem_get(mctx, sizeof(*lookup));
+ lookup->mctx = NULL;
+ isc_mem_attach(mctx, &lookup->mctx);
+ lookup->options = options;
+
+ ievent = isc_event_allocate(mctx, lookup, DNS_EVENT_LOOKUPDONE, action,
+ arg, sizeof(*lookup->event));
+ lookup->event = (dns_lookupevent_t *)ievent;
+ lookup->event->ev_destroy = levent_destroy;
+ lookup->event->ev_destroy_arg = mctx;
+ lookup->event->result = ISC_R_FAILURE;
+ lookup->event->name = NULL;
+ lookup->event->rdataset = NULL;
+ lookup->event->sigrdataset = NULL;
+ lookup->event->db = NULL;
+ lookup->event->node = NULL;
+
+ lookup->task = NULL;
+ isc_task_attach(task, &lookup->task);
+
+ isc_mutex_init(&lookup->lock);
+
+ dns_fixedname_init(&lookup->name);
+
+ dns_name_copynf(name, dns_fixedname_name(&lookup->name));
+
+ lookup->type = type;
+ lookup->view = NULL;
+ dns_view_attach(view, &lookup->view);
+ lookup->fetch = NULL;
+ lookup->restarts = 0;
+ lookup->canceled = false;
+ dns_rdataset_init(&lookup->rdataset);
+ dns_rdataset_init(&lookup->sigrdataset);
+ lookup->magic = LOOKUP_MAGIC;
+
+ *lookupp = lookup;
+
+ lookup_find(lookup, NULL);
+
+ return (ISC_R_SUCCESS);
+}
+
+void
+dns_lookup_cancel(dns_lookup_t *lookup) {
+ REQUIRE(VALID_LOOKUP(lookup));
+
+ LOCK(&lookup->lock);
+
+ if (!lookup->canceled) {
+ lookup->canceled = true;
+ if (lookup->fetch != NULL) {
+ INSIST(lookup->view != NULL);
+ dns_resolver_cancelfetch(lookup->fetch);
+ }
+ }
+
+ UNLOCK(&lookup->lock);
+}
+
+void
+dns_lookup_destroy(dns_lookup_t **lookupp) {
+ dns_lookup_t *lookup;
+
+ REQUIRE(lookupp != NULL);
+ lookup = *lookupp;
+ *lookupp = NULL;
+ REQUIRE(VALID_LOOKUP(lookup));
+ REQUIRE(lookup->event == NULL);
+ REQUIRE(lookup->task == NULL);
+ REQUIRE(lookup->view == NULL);
+ if (dns_rdataset_isassociated(&lookup->rdataset)) {
+ dns_rdataset_disassociate(&lookup->rdataset);
+ }
+ if (dns_rdataset_isassociated(&lookup->sigrdataset)) {
+ dns_rdataset_disassociate(&lookup->sigrdataset);
+ }
+
+ isc_mutex_destroy(&lookup->lock);
+ lookup->magic = 0;
+ isc_mem_putanddetach(&lookup->mctx, lookup, sizeof(*lookup));
+}