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bind/lib/dns/lookup.c
Michał Kępień 4df4a8e731 Use dns_fixedname_initname() where possible
Replace dns_fixedname_init() calls followed by dns_fixedname_name()
calls with calls to dns_fixedname_initname() where it is possible
without affecting current behavior and/or performance.

This patch was mostly prepared using Coccinelle and the following
semantic patch:

    @@
    expression fixedname, name;
    @@
    -	dns_fixedname_init(&fixedname);
    	...
    -	name = dns_fixedname_name(&fixedname);
    +	name = dns_fixedname_initname(&fixedname);

The resulting set of changes was then manually reviewed to exclude false
positives and apply minor tweaks.

It is likely that more occurrences of this pattern can be refactored in
an identical way.  This commit only takes care of the low-hanging fruit.
2018-04-09 12:14:16 +02:00

492 lines
12 KiB
C

/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* 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 http://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/* $Id: lookup.c,v 1.21 2007/06/18 23:47:40 tbox Exp $ */
/*! \file */
#include <config.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;
isc_boolean_t 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 inline 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;
isc_result_t result;
name = isc_mem_get(lookup->mctx, sizeof(dns_name_t));
if (name == NULL) {
result = ISC_R_NOMEMORY;
goto fail;
}
dns_name_init(name, NULL);
result = dns_name_dup(dns_fixedname_name(&lookup->name),
lookup->mctx, name);
if (result != ISC_R_SUCCESS)
goto fail;
if (dns_rdataset_isassociated(&lookup->rdataset)) {
rdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t));
if (rdataset == NULL) {
result = ISC_R_NOMEMORY;
goto fail;
}
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));
if (sigrdataset == NULL) {
result = ISC_R_NOMEMORY;
goto fail;
}
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);
fail:
if (name != NULL) {
if (dns_name_dynamic(name))
dns_name_free(name, lookup->mctx);
isc_mem_put(lookup->mctx, name, sizeof(dns_name_t));
}
if (rdataset != NULL) {
if (dns_rdataset_isassociated(rdataset))
dns_rdataset_disassociate(rdataset);
isc_mem_put(lookup->mctx, rdataset, sizeof(dns_rdataset_t));
}
return (result);
}
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, ISC_FALSE,
ISC_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;
isc_boolean_t want_restart;
isc_boolean_t 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 = ISC_FALSE;
send_event = ISC_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 = ISC_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;
result = dns_name_copy(&cname.cname, name, NULL);
dns_rdata_freestruct(&cname);
if (result == ISC_R_SUCCESS) {
want_restart = ISC_TRUE;
send_event = ISC_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 = ISC_TRUE;
send_event = ISC_FALSE;
}
break;
default:
send_event = ISC_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 = ISC_FALSE;
result = ISC_R_QUOTA;
send_event = ISC_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)
{
isc_result_t result;
dns_lookup_t *lookup;
isc_event_t *ievent;
lookup = isc_mem_get(mctx, sizeof(*lookup));
if (lookup == NULL)
return (ISC_R_NOMEMORY);
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));
if (ievent == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup_lookup;
}
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);
result = isc_mutex_init(&lookup->lock);
if (result != ISC_R_SUCCESS)
goto cleanup_event;
dns_fixedname_init(&lookup->name);
result = dns_name_copy(name, dns_fixedname_name(&lookup->name), NULL);
if (result != ISC_R_SUCCESS)
goto cleanup_lock;
lookup->type = type;
lookup->view = NULL;
dns_view_attach(view, &lookup->view);
lookup->fetch = NULL;
lookup->restarts = 0;
lookup->canceled = ISC_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);
cleanup_lock:
DESTROYLOCK(&lookup->lock);
cleanup_event:
ievent = (isc_event_t *)lookup->event;
isc_event_free(&ievent);
lookup->event = NULL;
isc_task_detach(&lookup->task);
cleanup_lookup:
isc_mem_putanddetach(&mctx, lookup, sizeof(*lookup));
return (result);
}
void
dns_lookup_cancel(dns_lookup_t *lookup) {
REQUIRE(VALID_LOOKUP(lookup));
LOCK(&lookup->lock);
if (!lookup->canceled) {
lookup->canceled = ISC_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;
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);
DESTROYLOCK(&lookup->lock);
lookup->magic = 0;
isc_mem_putanddetach(&lookup->mctx, lookup, sizeof(*lookup));
*lookupp = NULL;
}