lookup.c revision 573d78f3d53859bc01ce5d5cebbaac9b8b90bfba
/*
* Copyright (C) 2004, 2005, 2007, 2013 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $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, 0,
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,
&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) {
dns_fixedname_init(&foundname);
fname = dns_fixedname_name(&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.
*/
dns_fixedname_init(&fixed);
prefix = dns_fixedname_name(&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, 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;
}