resolver.c revision 3a19eddcc79b45a64b531eda7cf9efebcad84d11
/*
* Copyright (C) 1999 Internet Software Consortium.
*
* Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM 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.
*/
#include <config.h>
#include <isc/assertions.h>
#include <isc/error.h>
#include <isc/result.h>
#include <isc/timer.h>
#include <isc/mutex.h>
#include <isc/event.h>
#include <isc/task.h>
#include <isc/stdtime.h>
#include <dns/types.h>
#include <dns/result.h>
#include <dns/name.h>
#include <dns/db.h>
#include <dns/events.h>
#include <dns/message.h>
#include <dns/ncache.h>
#include <dns/dispatch.h>
#include <dns/resolver.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/tsig.h>
#include <dns/view.h>
#include <dns/log.h>
#include <dst/dst.h>
#include "../isc/util.h" /* XXX */
#define DNS_RESOLVER_TRACE
#ifdef DNS_RESOLVER_TRACE
#define RTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(1), \
"res %p: %s", res, (m))
#define RRTRACE(r, m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(1), \
"res %p: %s", (r), (m))
#define FCTXTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(1), \
"fctx %p: %s", fctx, (m))
#define FTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(1), \
"fetch %p (fctx %p): %s", \
fetch, fetch->private, (m))
#define QTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(1), \
"resquery %p (fctx %p): %s", \
query, query->fctx, (m))
#else
#define RTRACE(m)
#define RRTRACE(r, m)
#define FCTXTRACE(m)
#define FTRACE(m)
#define QTRACE(m)
#endif
typedef struct fetchctx fetchctx_t;
typedef struct query {
/* Not locked. */
unsigned int magic;
fetchctx_t * fctx;
dns_dispatch_t * dispatch;
/* Locked by fctx lock. */
dns_messageid_t id;
dns_dispentry_t * dispentry; /* XXX name */
ISC_LINK(struct query) link;
isc_buffer_t buffer;
dns_rdata_any_tsig_t *tsig;
dns_tsigkey_t *tsigkey;
unsigned char data[512];
} resquery_t;
#define QUERY_MAGIC 0x51212121U /* Q!!! */
#define VALID_QUERY(query) ((query) != NULL && \
(query)->magic == QUERY_MAGIC)
typedef enum {
fetchstate_init = 0,
fetchstate_active,
fetchstate_done
} fetchstate;
struct fetchctx {
/* Not locked. */
unsigned int magic;
dns_resolver_t * res;
dns_name_t name;
dns_rdatatype_t type;
unsigned int options;
isc_task_t * task;
unsigned int bucketnum;
/* Locked by lock. */
fetchstate state;
isc_boolean_t exiting;
unsigned int references;
isc_event_t control_event;
ISC_LINK(struct fetchctx) link;
ISC_LIST(dns_fetchevent_t) events;
/* Only changable by event actions running in the context's task */
dns_name_t domain;
dns_rdataset_t nameservers;
unsigned int attributes;
isc_timer_t * timer;
isc_time_t expires;
isc_interval_t interval;
dns_message_t * qmessage;
dns_message_t * rmessage;
ISC_LIST(resquery_t) queries;
ISC_LIST(isc_sockaddr_t) addresses;
isc_sockaddr_t * address;
};
#define FCTX_MAGIC 0x46212121U /* F!!! */
#define VALID_FCTX(fctx) ((fctx) != NULL && \
(fctx)->magic == FCTX_MAGIC)
#define FCTX_ATTR_HAVEANSWER 0x01
#define FCTX_ATTR_GLUING 0x02
#define HAVE_ANSWER(f) (((f)->attributes & FCTX_ATTR_HAVEANSWER) != \
0)
#define GLUING(f) (((f)->attributes & FCTX_ATTR_GLUING) != \
0)
struct dns_fetch {
unsigned int magic;
void * private;
};
#define DNS_FETCH_MAGIC 0x46746368U /* Ftch */
#define DNS_FETCH_VALID(fetch) ((fetch) != NULL && \
(fetch)->magic == DNS_FETCH_MAGIC)
typedef struct fctxbucket {
isc_task_t * task;
isc_mutex_t lock;
ISC_LIST(fetchctx_t) fctxs;
isc_boolean_t exiting;
} fctxbucket_t;
struct dns_resolver {
/* Unlocked */
unsigned int magic;
isc_mem_t * mctx;
isc_mutex_t lock;
dns_rdataclass_t rdclass;
isc_socketmgr_t * socketmgr;
isc_timermgr_t * timermgr;
dns_view_t * view;
/* Locked by lock. */
unsigned int references;
isc_boolean_t exiting;
isc_socket_t * udpsocket4;
isc_socket_t * udpsocket6;
dns_dispatch_t * dispatch4;
dns_dispatch_t * dispatch6;
unsigned int nbuckets;
unsigned int activebuckets;
fctxbucket_t * buckets;
};
#define RES_MAGIC 0x52657321U /* Res! */
#define VALID_RESOLVER(res) ((res) != NULL && \
(res)->magic == RES_MAGIC)
static void destroy(dns_resolver_t *res);
static void empty_bucket(dns_resolver_t *res);
static void resquery_response(isc_task_t *task, isc_event_t *event);
static inline isc_result_t
fctx_starttimer(fetchctx_t *fctx) {
return (isc_timer_reset(fctx->timer, isc_timertype_once,
&fctx->expires, &fctx->interval,
ISC_FALSE));
}
static inline isc_result_t
fctx_stopidletimer(fetchctx_t *fctx) {
return (isc_timer_reset(fctx->timer, isc_timertype_once,
&fctx->expires, NULL,
ISC_FALSE));
}
static inline void
fctx_stoptimer(fetchctx_t *fctx) {
isc_result_t result;
/*
* We don't return a result if resetting the timer to inactive fails
* since there's nothing to be done about it. Resetting to inactive
* should never fail anyway, since the code as currently written
* cannot fail in that case.
*/
result = isc_timer_reset(fctx->timer, isc_timertype_inactive,
NULL, NULL, ISC_TRUE);
if (result != ISC_R_SUCCESS) {
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_timer_reset(): %s",
isc_result_totext(result));
}
}
static inline void
fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp) {
fetchctx_t *fctx;
resquery_t *query;
query = *queryp;
fctx = query->fctx;
FCTXTRACE("cancelquery");
dns_dispatch_removeresponse(query->dispatch, &query->dispentry,
deventp);
ISC_LIST_UNLINK(fctx->queries, query, link);
query->magic = 0;
if (query->tsig != NULL)
dns_rdata_freestruct(query->tsig);
isc_mem_put(fctx->res->mctx, query, sizeof *query);
*queryp = NULL;
}
static void
fctx_cancelqueries(fetchctx_t *fctx) {
resquery_t *query, *next_query;
FCTXTRACE("cancelqueries");
for (query = ISC_LIST_HEAD(fctx->queries);
query != NULL;
query = next_query) {
next_query = ISC_LIST_NEXT(query, link);
fctx_cancelquery(&query, NULL);
}
}
static void
fctx_freeaddresses(fetchctx_t *fctx) {
isc_sockaddr_t *address, *next_address;
for (address = ISC_LIST_HEAD(fctx->addresses);
address != NULL;
address = next_address) {
next_address = ISC_LIST_NEXT(address, link);
isc_mem_put(fctx->res->mctx, address, sizeof *address);
}
ISC_LIST_INIT(fctx->addresses);
fctx->address = NULL;
}
static void
fctx_done(fetchctx_t *fctx, isc_result_t result) {
dns_fetchevent_t *event, *next_event;
isc_task_t *task;
dns_resolver_t *res;
FCTXTRACE("done");
res = fctx->res;
fctx_freeaddresses(fctx);
fctx_cancelqueries(fctx);
fctx_stoptimer(fctx);
LOCK(&res->buckets[fctx->bucketnum].lock);
fctx->state = fetchstate_done;
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, link);
task = event->sender;
event->sender = fctx;
if (!HAVE_ANSWER(fctx))
event->result = result;
isc_task_sendanddetach(&task, (isc_event_t **)&event);
}
ISC_LIST_INIT(fctx->events);
/*
* XXXRTH check for finished state.
*/
UNLOCK(&res->buckets[fctx->bucketnum].lock);
}
static void
resquery_senddone(isc_task_t *task, isc_event_t *event) {
isc_socketevent_t *sevent = (isc_socketevent_t *)event;
resquery_t *query = event->arg;
REQUIRE(event->type == ISC_SOCKEVENT_SENDDONE);
/*
* XXXRTH
*
* Currently we don't wait for the senddone event before retrying
* a query. This means that if we get really behind, we may end
* up doing extra work!
*/
(void)task;
if (sevent->result != ISC_R_SUCCESS)
fctx_cancelquery(&query, NULL);
isc_event_free(&event);
}
static isc_result_t
fctx_sendquery(fetchctx_t *fctx, isc_sockaddr_t *address) {
resquery_t *query;
isc_result_t result;
dns_rdataset_t *qrdataset;
dns_name_t *qname;
isc_region_t r;
dns_resolver_t *res;
isc_task_t *task;
FCTXTRACE("sendquery");
res = fctx->res;
task = res->buckets[fctx->bucketnum].task;
result = fctx_starttimer(fctx);
if (result != ISC_R_SUCCESS)
return (result);
dns_message_reset(fctx->rmessage, DNS_MESSAGE_INTENTPARSE);
qname = NULL;
result = dns_message_gettempname(fctx->qmessage, &qname);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
qrdataset = NULL;
result = dns_message_gettemprdataset(fctx->qmessage, &qrdataset);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
query = isc_mem_get(res->mctx, sizeof *query);
if (query == NULL)
return (ISC_R_NOMEMORY);
isc_buffer_init(&query->buffer, query->data, sizeof query->data,
ISC_BUFFERTYPE_BINARY);
/*
* If this is a TCP query, then we need to make a socket and
* a dispatch for it here. Otherwise we use the resolver's
* shared dispatch. We do not attach to the resolver's shared
* dispatch if we use it, so the resolver MUST ensure that no
* fetches are running before changing the shared dispatch.
*/
if ((fctx->options & DNS_FETCHOPT_TCP) != 0) {
/* XXXRTH */
result = DNS_R_NOTIMPLEMENTED;
goto cleanup_query;
} else {
switch (isc_sockaddr_pf(address)) {
case AF_INET:
query->dispatch = res->dispatch4;
break;
case AF_INET6:
query->dispatch = res->dispatch6;
break;
default:
result = DNS_R_NOTIMPLEMENTED;
goto cleanup_query;
}
/*
* We should always have a valid dispatcher here. If we
* don't support a protocol family, then its dispatcher
* will be NULL, but we shouldn't be finding addresses for
* protocol types we don't support, so the dispatcher
* we found should never be NULL.
*/
INSIST(query->dispatch != NULL);
}
/*
* Get a query id from the dispatch.
*/
query->dispentry = NULL;
result = dns_dispatch_addresponse(query->dispatch,
address,
task,
resquery_response,
query,
&query->id,
&query->dispentry);
if (result != ISC_R_SUCCESS)
goto cleanup_query;
query->fctx = fctx;
query->tsig = NULL;
query->tsigkey = NULL;
query->magic = QUERY_MAGIC;
fctx->qmessage->opcode = dns_opcode_query;
/*
* Set up question.
*/
dns_name_init(qname, NULL);
dns_name_clone(&fctx->name, qname);
dns_rdataset_init(qrdataset);
dns_rdataset_makequestion(qrdataset, res->rdclass, fctx->type);
ISC_LIST_APPEND(qname->list, qrdataset, link);
dns_message_addname(fctx->qmessage, qname, DNS_SECTION_QUESTION);
if ((fctx->options & DNS_FETCHOPT_RECURSIVE) != 0)
fctx->qmessage->flags |= DNS_MESSAGEFLAG_RD;
/*
* We don't have to set opcode because it defaults to query.
*/
fctx->qmessage->id = query->id;
/*
* XXXRTH Add TSIG and/or ENDS0 OPT record tailored to the current
* recipient.
*/
/*
* Convert the question to wire format.
*/
result = dns_message_renderbegin(fctx->qmessage, &query->buffer);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_rendersection(fctx->qmessage,
DNS_SECTION_QUESTION, 0, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_rendersection(fctx->qmessage,
DNS_SECTION_ADDITIONAL, 0, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_renderend(fctx->qmessage);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
if (fctx->qmessage->tsigkey != NULL) {
query->tsigkey = fctx->qmessage->tsigkey;
query->tsig = fctx->qmessage->tsig;
fctx->qmessage->tsig = NULL;
}
/*
* We're now done with the query message.
*/
dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
/*
* Send the query!
*/
isc_buffer_used(&query->buffer, &r);
result = isc_socket_sendto(dns_dispatch_getsocket(query->dispatch),
&r, task, resquery_senddone,
query, address);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
/*
* Finally, we've got everything going!
*/
ISC_LIST_APPEND(fctx->queries, query, link);
QTRACE("sent");
return (ISC_R_SUCCESS);
cleanup_message:
dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
/*
* Stop the dispatcher from listening.
*/
dns_dispatch_removeresponse(query->dispatch,
&query->dispentry,
NULL);
/*
* XXXRTH will need to cleanup a nonshared dispatch and TCP socket
* here.
*/
cleanup_query:
query->magic = 0;
isc_mem_put(res->mctx, query, sizeof *query);
cleanup_temps:
if (qname != NULL)
dns_message_puttempname(fctx->qmessage, &qname);
if (qrdataset != NULL)
dns_message_puttemprdataset(fctx->qmessage, &qrdataset);
fctx_stoptimer(fctx);
return (result);
}
static isc_result_t
fctx_getaddresses(fetchctx_t *fctx) {
isc_boolean_t use_hints;
dns_rdata_t rdata;
isc_region_t r;
dns_name_t name;
dns_rdataset_t rdataset;
isc_sockaddr_t *address;
struct in_addr ina;
isc_result_t result;
FCTXTRACE("getaddresses");
/*
* XXXRTH We don't try to handle forwarding yet.
*/
/*
* XXXRTH This code is a temporary hack until we have working
* address code.
*/
ISC_LIST_INIT(fctx->addresses);
fctx->address = NULL;
use_hints = dns_name_equal(&fctx->domain, dns_rootname);
INSIST(fctx->nameservers.type == dns_rdatatype_ns);
result = dns_rdataset_first(&fctx->nameservers);
while (result == ISC_R_SUCCESS) {
dns_rdataset_current(&fctx->nameservers, &rdata);
dns_rdata_toregion(&rdata, &r);
dns_name_init(&name, NULL);
dns_name_fromregion(&name, &r);
dns_rdataset_init(&rdataset);
result = dns_view_find(fctx->res->view, &name,
dns_rdatatype_a, 0, DNS_DBFIND_GLUEOK,
use_hints, &rdataset, NULL);
if (result == ISC_R_SUCCESS ||
result == DNS_R_GLUE ||
result == DNS_R_HINT) {
result = dns_rdataset_first(&rdataset);
while (result == ISC_R_SUCCESS) {
address = isc_mem_get(fctx->res->mctx,
sizeof *address);
if (address == NULL) {
result = ISC_R_NOMEMORY;
break;
}
dns_rdataset_current(&rdataset, &rdata);
INSIST(rdata.length == 4);
memcpy(&ina.s_addr, rdata.data, 4);
isc_sockaddr_fromin(address, &ina, 53);
ISC_LIST_APPEND(fctx->addresses, address,
link);
result = dns_rdataset_next(&rdataset);
}
}
if (dns_rdataset_isassociated(&rdataset))
dns_rdataset_disassociate(&rdataset);
result = dns_rdataset_next(&fctx->nameservers);
}
if (result == DNS_R_NOMORE)
result = ISC_R_SUCCESS;
return (result);
}
static void
fctx_try(fetchctx_t *fctx) {
isc_result_t result;
/*
* Caller must be holding the fetch's lock.
*/
FCTXTRACE("try");
if (fctx->address != NULL)
fctx->address = ISC_LIST_NEXT(fctx->address, link);
if (fctx->address == NULL) {
fctx_freeaddresses(fctx);
fctx_cancelqueries(fctx);
result = fctx_getaddresses(fctx);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, result);
return;
}
fctx->address = ISC_LIST_HEAD(fctx->addresses);
}
if (fctx->address == NULL) {
/*
* XXXRTH No addresses are available...
*/
INSIST(0);
}
/*
* XXXRTH This is the place where a try strategy routine would
* be called to send one or more queries. Instead, we
* just send a single query.
*/
result = fctx_sendquery(fctx, fctx->address);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result);
}
static isc_boolean_t
fctx_destroy(fetchctx_t *fctx) {
dns_resolver_t *res;
unsigned int bucketnum;
/*
* Caller must be holding the bucket lock.
*/
REQUIRE(VALID_FCTX(fctx));
REQUIRE(fctx->state == fetchstate_done);
REQUIRE(ISC_LIST_EMPTY(fctx->events));
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
FCTXTRACE("destroy");
res = fctx->res;
bucketnum = fctx->bucketnum;
ISC_LIST_UNLINK(res->buckets[bucketnum].fctxs, fctx, link);
isc_timer_detach(&fctx->timer);
dns_message_destroy(&fctx->rmessage);
dns_message_destroy(&fctx->qmessage);
if (dns_name_countlabels(&fctx->domain) > 0) {
if (dns_rdataset_isassociated(&fctx->nameservers))
dns_rdataset_disassociate(&fctx->nameservers);
dns_name_free(&fctx->domain, res->mctx);
}
dns_name_free(&fctx->name, fctx->res->mctx);
isc_mem_put(res->mctx, fctx, sizeof *fctx);
if (res->buckets[bucketnum].exiting &&
ISC_LIST_EMPTY(res->buckets[bucketnum].fctxs))
return (ISC_TRUE);
return (ISC_FALSE);
}
/*
* Fetch event handlers.
*/
static void
fctx_timeout(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->arg;
REQUIRE(VALID_FCTX(fctx));
(void)task; /* Keep compiler quiet. */
FCTXTRACE("timeout");
if (event->type == ISC_TIMEREVENT_LIFE) {
fctx_cancelqueries(fctx);
fctx_done(fctx, DNS_R_TIMEDOUT);
} else {
/*
* We could cancel the running queries here, or we could let
* them keep going. Right now we choose the latter...
*/
fctx_try(fctx);
}
isc_event_free(&event);
}
static void
fctx_shutdown(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->arg;
isc_boolean_t need_done = ISC_FALSE, bucket_empty = ISC_FALSE;
dns_resolver_t *res;
unsigned int bucketnum;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
bucketnum = fctx->bucketnum;
(void)task; /* Keep compiler quiet. */
FCTXTRACE("shutdown");
LOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->state == fetchstate_active ||
fctx->state == fetchstate_done);
INSIST(fctx->exiting);
if (fctx->state == fetchstate_done) {
if (fctx->references == 0)
bucket_empty = fctx_destroy(fctx);
} else
need_done = ISC_TRUE;
UNLOCK(&res->buckets[bucketnum].lock);
if (need_done)
fctx_done(fctx, ISC_R_CANCELED);
else if (bucket_empty)
empty_bucket(res);
}
static void
fctx_start(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->arg;
isc_boolean_t done = ISC_FALSE, bucket_empty = ISC_FALSE;
dns_resolver_t *res;
unsigned int bucketnum;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
bucketnum = fctx->bucketnum;
(void)task; /* Keep compiler quiet. */
FCTXTRACE("start");
LOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->state == fetchstate_init);
if (fctx->exiting) {
/*
* We haven't started this fctx yet, and we've been requested
* to shut it down.
*
* The events list should be empty, so we INSIST on it.
*/
INSIST(ISC_LIST_EMPTY(fctx->events));
bucket_empty = fctx_destroy(fctx);
done = ISC_TRUE;
} else {
/*
* Normal fctx startup.
*/
fctx->state = fetchstate_active;
/*
* Reset the control event for later use in shutting down
* the fctx.
*/
ISC_EVENT_INIT(event, sizeof *event, 0, NULL,
DNS_EVENT_FETCHCONTROL, fctx_shutdown, fctx,
(void *)fctx_shutdown, NULL, NULL);
}
UNLOCK(&res->buckets[bucketnum].lock);
if (!done) {
/*
* All is well. Start working on the fetch.
*/
fctx_try(fctx);
} else if (bucket_empty)
empty_bucket(res);
}
/*
* Fetch Creation, Joining, and Cancelation.
*/
static inline isc_result_t
fctx_join(fetchctx_t *fctx, isc_task_t *task, isc_taskaction_t action,
void *arg, dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
dns_fetch_t *fetch)
{
isc_task_t *clone;
dns_fetchevent_t *event;
FCTXTRACE("join");
/*
* We store the task we're going to send this event to in the
* sender field. We'll make the fetch the sender when we actually
* send the event.
*/
clone = NULL;
isc_task_attach(task, &clone);
event = (dns_fetchevent_t *)
isc_event_allocate(fctx->res->mctx, clone,
DNS_EVENT_FETCHDONE,
action, arg, sizeof *event);
if (event == NULL)
return (ISC_R_NOMEMORY);
event->result = DNS_R_SERVFAIL;
event->qtype = fctx->type;
event->db = NULL;
event->node = NULL;
event->rdataset = rdataset;
event->sigrdataset = sigrdataset;
event->fetch = fetch;
dns_fixedname_init(&event->foundname);
ISC_LIST_APPEND(fctx->events, event, link);
fctx->references++;
fetch->magic = DNS_FETCH_MAGIC;
fetch->private = fctx;
return (ISC_R_SUCCESS);
}
static isc_result_t
fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
dns_name_t *domain, dns_rdataset_t *nameservers,
unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp)
{
fetchctx_t *fctx;
isc_result_t result = ISC_R_SUCCESS;
isc_result_t iresult;
isc_interval_t interval;
/*
* Caller must be holding the lock for bucket number 'bucketnum'.
*/
REQUIRE(fctxp != NULL && *fctxp == NULL);
fctx = isc_mem_get(res->mctx, sizeof *fctx);
if (fctx == NULL)
return (ISC_R_NOMEMORY);
FCTXTRACE("create");
dns_name_init(&fctx->name, NULL);
result = dns_name_dup(name, res->mctx, &fctx->name);
if (result != ISC_R_SUCCESS)
goto cleanup_fetch;
dns_name_init(&fctx->domain, NULL);
dns_rdataset_init(&fctx->nameservers);
if (domain != NULL) {
result = dns_name_dup(domain, res->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
goto cleanup_name;
dns_rdataset_clone(nameservers, &fctx->nameservers);
}
fctx->type = type;
fctx->options = options;
/*
* Note! We do not attach to the task. We are relying on the
* resolver to ensure that this task doesn't go away while we are
* using it.
*/
fctx->res = res;
fctx->references = 0;
fctx->bucketnum = bucketnum;
fctx->state = fetchstate_init;
fctx->exiting = ISC_FALSE;
ISC_LIST_INIT(fctx->queries);
ISC_LIST_INIT(fctx->addresses);
fctx->address = NULL;
fctx->attributes = 0;
fctx->qmessage = NULL;
result = dns_message_create(res->mctx, DNS_MESSAGE_INTENTRENDER,
&fctx->qmessage);
if (result != ISC_R_SUCCESS)
goto cleanup_domain;
fctx->rmessage = NULL;
result = dns_message_create(res->mctx, DNS_MESSAGE_INTENTPARSE,
&fctx->rmessage);
if (result != ISC_R_SUCCESS)
goto cleanup_qmessage;
/*
* Compute an expiration time for the entire fetch.
*/
isc_interval_set(&interval, 30, 0); /* XXXRTH constant */
iresult = isc_time_nowplusinterval(&fctx->expires, &interval);
if (iresult != ISC_R_SUCCESS) {
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_time_nowplusinterval: %s",
isc_result_totext(iresult));
result = DNS_R_UNEXPECTED;
goto cleanup_rmessage;
}
/*
* XXX Retry interval initialization. Should be setup by the
* transmission strategy routine (when we have one).
*/
isc_interval_set(&fctx->interval, 1, 500000000);
/*
* Create an inactive timer. It will be made active when the fetch
* is actually started.
*/
fctx->timer = NULL;
iresult = isc_timer_create(res->timermgr, isc_timertype_inactive,
NULL, NULL,
res->buckets[bucketnum].task, fctx_timeout,
fctx, &fctx->timer);
if (iresult != ISC_R_SUCCESS) {
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_timer_create: %s",
isc_result_totext(iresult));
result = DNS_R_UNEXPECTED;
goto cleanup_rmessage;
}
ISC_LIST_INIT(fctx->events);
ISC_LINK_INIT(fctx, link);
fctx->magic = FCTX_MAGIC;
ISC_LIST_APPEND(res->buckets[bucketnum].fctxs, fctx, link);
*fctxp = fctx;
return (ISC_R_SUCCESS);
cleanup_rmessage:
dns_message_destroy(&fctx->rmessage);
cleanup_qmessage:
dns_message_destroy(&fctx->qmessage);
cleanup_domain:
if (dns_name_countlabels(&fctx->domain) > 0) {
dns_rdataset_disassociate(&fctx->nameservers);
dns_name_free(&fctx->domain, res->mctx);
}
cleanup_name:
dns_name_free(&fctx->name, res->mctx);
cleanup_fetch:
isc_mem_put(res->mctx, fctx, sizeof *fctx);
return (result);
}
/*
* Handle Responses
*/
static inline isc_result_t
same_question(fetchctx_t *fctx) {
isc_result_t result;
dns_message_t *message = fctx->rmessage;
dns_name_t *name;
dns_rdataset_t *rdataset;
/*
* Caller must be holding the fctx lock.
*/
/*
* XXXRTH Currently we support only one question.
*/
if (message->counts[DNS_SECTION_QUESTION] != 1)
return (DNS_R_FORMERR);
result = dns_message_firstname(message, DNS_SECTION_QUESTION);
if (result != ISC_R_SUCCESS)
return (result);
name = NULL;
dns_message_currentname(message, DNS_SECTION_QUESTION, &name);
rdataset = ISC_LIST_HEAD(name->list);
INSIST(rdataset != NULL);
INSIST(ISC_LIST_NEXT(rdataset, link) == NULL);
if (fctx->type != rdataset->type ||
fctx->res->rdclass != rdataset->rdclass ||
!dns_name_equal(&fctx->name, name))
return (DNS_R_FORMERR);
return (ISC_R_SUCCESS);
}
static void
clone_results(fetchctx_t *fctx) {
dns_fetchevent_t *event, *hevent;
isc_result_t result;
dns_name_t *name, *hname;
/*
* Set up any other events to have the same data as the first
* event.
*
* Caller must be holding the appropriate lock.
*/
hevent = ISC_LIST_HEAD(fctx->events);
if (hevent == NULL)
return;
hname = dns_fixedname_name(&hevent->foundname);
for (event = ISC_LIST_NEXT(hevent, link);
event != NULL;
event = ISC_LIST_NEXT(event, link)) {
name = dns_fixedname_name(&event->foundname);
result = dns_name_concatenate(hname, NULL, name, NULL);
if (result != ISC_R_SUCCESS)
event->result = result;
else
event->result = hevent->result;
dns_db_attach(hevent->db, &event->db);
dns_db_attachnode(hevent->db, hevent->node, &event->node);
if (hevent->rdataset != NULL &&
dns_rdataset_isassociated(hevent->rdataset))
dns_rdataset_clone(hevent->rdataset, event->rdataset);
if (hevent->sigrdataset != NULL &&
dns_rdataset_isassociated(hevent->sigrdataset))
dns_rdataset_clone(hevent->sigrdataset,
event->sigrdataset);
}
}
#define CACHE(r) (((r)->attributes & DNS_RDATASETATTR_CACHE) != 0)
#define ANSWER(r) (((r)->attributes & DNS_RDATASETATTR_ANSWER) != 0)
#define ANSWERSIG(r) (((r)->attributes & DNS_RDATASETATTR_ANSWERSIG) != 0)
#define EXTERNAL(r) (((r)->attributes & DNS_RDATASETATTR_EXTERNAL) != 0)
#define CHAINING(r) (((r)->attributes & DNS_RDATASETATTR_CHAINING) != 0)
static inline isc_result_t
cache_name(fetchctx_t *fctx, dns_name_t *name, isc_stdtime_t now) {
dns_rdataset_t *rdataset, *addedrdataset, *ardataset, *asigrdataset;
dns_dbnode_t *node, **anodep;
dns_db_t **adbp;
dns_fixedname_t foundname;
dns_name_t *fname, *aname;
dns_resolver_t *res;
void *data;
isc_boolean_t need_validation, have_answer;
isc_result_t result, eresult;
dns_fetchevent_t *event;
/*
* The appropriate bucket lock must be held.
*/
res = fctx->res;
need_validation = ISC_FALSE;
have_answer = ISC_FALSE;
eresult = ISC_R_SUCCESS;
/*
* Is DNSSEC validation required for this name?
*/
dns_fixedname_init(&foundname);
fname = dns_fixedname_name(&foundname);
data = NULL;
result = dns_rbt_findname(res->view->secroots, name, fname, &data);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
/*
* This name is at or below one of the view's security roots,
* so DNSSEC validation is required.
*/
need_validation = ISC_TRUE;
} else if (result != ISC_R_NOTFOUND) {
/*
* Something bad happened.
*/
return (result);
}
adbp = NULL;
aname = NULL;
anodep = NULL;
ardataset = NULL;
asigrdataset = NULL;
event = NULL;
if ((name->attributes & DNS_NAMEATTR_ANSWER) != 0) {
have_answer = ISC_TRUE;
event = ISC_LIST_HEAD(fctx->events);
if (event != NULL) {
adbp = &event->db;
aname = dns_fixedname_name(&event->foundname);
result = dns_name_concatenate(name, NULL, aname, NULL);
if (result != ISC_R_SUCCESS)
return (result);
anodep = &event->node;
if (fctx->type != dns_rdatatype_any &&
fctx->type != dns_rdatatype_sig) {
ardataset = event->rdataset;
asigrdataset = event->sigrdataset;
}
}
}
/*
* Find or create the cache node.
*/
node = NULL;
result = dns_db_findnode(res->view->cachedb,
name, ISC_TRUE,
&node);
if (result != ISC_R_SUCCESS)
return (result);
/*
* Cache or validate each cacheable rdataset.
*/
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (!CACHE(rdataset))
continue;
if (need_validation) {
/*
* XXXRTH.
*/
return (DNS_R_NOTIMPLEMENTED);
} else if (!EXTERNAL(rdataset)) {
/*
* It's OK to cache this rdataset now.
*/
if (ANSWER(rdataset))
addedrdataset = ardataset;
else
addedrdataset = NULL;
if (CHAINING(rdataset)) {
if (rdataset->type == dns_rdatatype_cname)
eresult = DNS_R_CNAME;
else {
INSIST(rdataset->type ==
dns_rdatatype_dname);
eresult = DNS_R_DNAME;
}
}
result = dns_db_addrdataset(res->view->cachedb,
node, NULL, now,
rdataset,
ISC_FALSE,
addedrdataset);
if (result == DNS_R_UNCHANGED) {
if (ANSWER(rdataset) &&
ardataset != NULL &&
ardataset->type == 0) {
/*
* The answer in the cache is better
* than the answer we found, and is
* a negative cache entry, so we
* must set eresult appropriately.
*/
if (ardataset->covers ==
dns_rdatatype_any)
eresult =
DNS_R_NCACHENXDOMAIN;
else
eresult =
DNS_R_NCACHENXRRSET;
}
result = ISC_R_SUCCESS;
} else if (result != ISC_R_SUCCESS)
break;
}
}
if (result == ISC_R_SUCCESS && have_answer) {
fctx->attributes |= FCTX_ATTR_HAVEANSWER;
if (event != NULL) {
event->result = eresult;
dns_db_attach(res->view->cachedb, adbp);
*anodep = node;
clone_results(fctx);
}
} else
dns_db_detachnode(res->view->cachedb, &node);
return (result);
}
static inline isc_result_t
cache_message(fetchctx_t *fctx) {
isc_result_t result;
dns_section_t section;
dns_name_t *name;
isc_stdtime_t now;
result = isc_stdtime_get(&now);
if (result != ISC_R_SUCCESS)
return (result);
LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
for (section = DNS_SECTION_ANSWER;
section <= DNS_SECTION_ADDITIONAL;
section++) {
result = dns_message_firstname(fctx->rmessage, section);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(fctx->rmessage, section,
&name);
if ((name->attributes & DNS_NAMEATTR_CACHE) != 0) {
result = cache_name(fctx, name, now);
if (result != ISC_R_SUCCESS)
break;
}
result = dns_message_nextname(fctx->rmessage, section);
}
if (result != ISC_R_NOMORE)
break;
}
if (result == ISC_R_NOMORE)
result = ISC_R_SUCCESS;
UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
return (result);
}
static inline isc_result_t
ncache_message(fetchctx_t *fctx, dns_rdatatype_t covers, isc_stdtime_t now) {
isc_result_t result, eresult;
dns_name_t *name;
dns_resolver_t *res;
dns_db_t **adbp;
dns_dbnode_t *node, **anodep;
dns_rdataset_t *ardataset;
isc_boolean_t need_validation;
dns_fixedname_t foundname;
dns_name_t *fname, *aname;
dns_fetchevent_t *event;
void *data;
res = fctx->res;
need_validation = ISC_FALSE;
eresult = ISC_R_SUCCESS;
name = &fctx->name;
/*
* Is DNSSEC validation required for this name?
*/
dns_fixedname_init(&foundname);
fname = dns_fixedname_name(&foundname);
data = NULL;
result = dns_rbt_findname(res->view->secroots, name, fname, &data);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
/*
* This name is at or below one of the view's security roots,
* so DNSSEC validation is required.
*/
need_validation = ISC_TRUE;
} else if (result != ISC_R_NOTFOUND) {
/*
* Something bad happened.
*/
return (result);
}
LOCK(&res->buckets[fctx->bucketnum].lock);
adbp = NULL;
aname = NULL;
anodep = NULL;
ardataset = NULL;
event = ISC_LIST_HEAD(fctx->events);
if (event != NULL) {
adbp = &event->db;
aname = dns_fixedname_name(&event->foundname);
result = dns_name_concatenate(name, NULL, aname, NULL);
if (result != ISC_R_SUCCESS)
goto unlock;
anodep = &event->node;
ardataset = event->rdataset;
}
node = NULL;
result = dns_db_findnode(res->view->cachedb, name, ISC_TRUE,
&node);
if (result != ISC_R_SUCCESS)
goto unlock;
result = dns_ncache_add(fctx->rmessage, res->view->cachedb, node,
covers, now, ardataset);
if (result == DNS_R_UNCHANGED) {
/*
* The data in the cache is better than the negative cache
* entry we're trying to add.
*/
if (ardataset != NULL && ardataset->type == 0) {
/*
* The cache data is also a negative cache
* entry.
*/
if (ardataset->covers == dns_rdatatype_any)
eresult = DNS_R_NCACHENXDOMAIN;
else
eresult = DNS_R_NCACHENXRRSET;
} else {
/*
* Either we don't care about the nature of the
* cache rdataset (because no fetch is interested
* in the outcome), or the cache rdataset is not
* a negative cache entry. Whichever case it is,
* we can return success. In the latter case,
* 'eresult' is already set correctly.
*/
result = ISC_R_SUCCESS;
}
} else if (result == ISC_R_SUCCESS) {
if (covers == dns_rdatatype_any)
eresult = DNS_R_NCACHENXDOMAIN;
else
eresult = DNS_R_NCACHENXRRSET;
} else
goto unlock;
fctx->attributes |= FCTX_ATTR_HAVEANSWER;
if (event != NULL) {
event->result = eresult;
dns_db_attach(res->view->cachedb, adbp);
*anodep = node;
node = NULL;
clone_results(fctx);
}
unlock:
UNLOCK(&res->buckets[fctx->bucketnum].lock);
if (node != NULL)
dns_db_detachnode(res->view->cachedb, &node);
return (result);
}
static inline void
mark_related(dns_name_t *name, dns_rdataset_t *rdataset,
isc_boolean_t external, isc_boolean_t gluing)
{
name->attributes |= DNS_NAMEATTR_CACHE;
if (gluing)
rdataset->trust = dns_trust_glue;
else
rdataset->trust = dns_trust_additional;
rdataset->attributes |= DNS_RDATASETATTR_CACHE;
if (external)
rdataset->attributes |= DNS_RDATASETATTR_EXTERNAL;
}
static isc_result_t
check_related(void *arg, dns_name_t *addname, dns_rdatatype_t type) {
fetchctx_t *fctx = arg;
isc_result_t result;
dns_name_t *name;
dns_rdataset_t *rdataset;
isc_boolean_t external;
dns_rdatatype_t rtype;
isc_boolean_t gluing;
REQUIRE(VALID_FCTX(fctx));
if (GLUING(fctx))
gluing = ISC_TRUE;
else
gluing = ISC_FALSE;
name = NULL;
rdataset = NULL;
result = dns_message_findname(fctx->rmessage, DNS_SECTION_ADDITIONAL,
addname, dns_rdatatype_any, 0, &name,
NULL);
if (result == ISC_R_SUCCESS) {
external = !dns_name_issubdomain(name, &fctx->domain);
if (type == dns_rdatatype_a) {
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (rdataset->type == dns_rdatatype_sig)
rtype = rdataset->covers;
else
rtype = rdataset->type;
if (rtype == dns_rdatatype_a ||
rtype == dns_rdatatype_aaaa ||
rtype == dns_rdatatype_a6)
mark_related(name, rdataset, external,
gluing);
/*
* XXXRTH Need to do a controlled recursion
* on the A6 prefix names to mark
* any additional data related to them.
*
* Ick.
*/
}
} else {
result = dns_message_findtype(name, type, 0,
&rdataset);
if (result == ISC_R_SUCCESS) {
mark_related(name, rdataset, external, gluing);
/*
* Do we have its SIG too?
*/
result = dns_message_findtype(name,
dns_rdatatype_sig,
type, &rdataset);
if (result == ISC_R_SUCCESS)
mark_related(name, rdataset, external,
gluing);
}
}
/*
* XXXRTH Some other stuff still needs to be marked.
* See query.c.
*/
}
return (ISC_R_SUCCESS);
}
static inline isc_result_t
cname_target(dns_rdataset_t *rdataset, dns_name_t *tname) {
isc_result_t result;
dns_rdata_t rdata;
isc_region_t r;
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS)
return (result);
dns_rdataset_current(rdataset, &rdata);
dns_rdata_toregion(&rdata, &r);
dns_name_init(tname, NULL);
dns_name_fromregion(tname, &r);
return (ISC_R_SUCCESS);
}
static inline isc_result_t
dname_target(dns_rdataset_t *rdataset, dns_name_t *qname, dns_name_t *oname,
dns_fixedname_t *fixeddname)
{
isc_result_t result;
dns_rdata_t rdata;
isc_region_t r;
dns_name_t *dname, tname;
unsigned int nlabels, nbits;
int order;
dns_namereln_t namereln;
/*
* Get the target name of the DNAME.
*/
dns_fixedname_init(fixeddname);
dname = dns_fixedname_name(fixeddname);
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS)
return (result);
dns_rdataset_current(rdataset, &rdata);
dns_rdata_toregion(&rdata, &r);
dns_name_init(&tname, NULL);
dns_name_fromregion(&tname, &r);
/*
* Get the prefix of qname.
*/
namereln = dns_name_fullcompare(qname, oname, &order, &nlabels,
&nbits);
if (namereln != dns_namereln_subdomain)
return (DNS_R_FORMERR);
result = dns_name_split(qname, nlabels, nbits, dname, NULL);
if (result != ISC_R_SUCCESS)
return (result);
return (dns_name_concatenate(dname, &tname, dname, NULL));
}
static isc_result_t
noanswer_response(fetchctx_t *fctx, dns_name_t *oqname) {
isc_result_t result;
dns_message_t *message;
dns_name_t *name, *qname, *ns_name, *soa_name;
dns_rdataset_t *rdataset;
isc_boolean_t done, aa, negative_response;
dns_rdatatype_t type;
message = fctx->rmessage;
/*
* Setup qname.
*/
if (oqname == NULL) {
/*
* We have a normal, non-chained negative response or
* referral.
*/
if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
aa = ISC_TRUE;
else
aa = ISC_FALSE;
qname = &fctx->name;
} else {
/*
* We're being invoked by answer_response() after it has
* followed a CNAME/DNAME chain.
*/
qname = oqname;
aa = ISC_FALSE;
}
/*
* We have to figure out if this is a negative response, or a
* referral. We start by examining the rcode.
*/
negative_response = ISC_FALSE;
if (message->rcode == dns_rcode_nxdomain)
negative_response = ISC_TRUE;
done = ISC_FALSE;
ns_name = NULL;
soa_name = NULL;
result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
while (!done && result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
if (dns_name_issubdomain(name, &fctx->domain)) {
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
type = rdataset->type;
if (type == dns_rdatatype_sig)
type = rdataset->covers;
if (rdataset->type == dns_rdatatype_ns) {
/*
* NS or SIG NS.
*
* Only one set of NS RRs is allowed.
*/
if (ns_name != NULL && name != ns_name)
return (DNS_R_FORMERR);
ns_name = name;
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
rdataset->trust = dns_trust_glue;
/*
* Mark any additional data related
* to this rdataset.
*/
fctx->attributes |=
FCTX_ATTR_GLUING;
(void)dns_rdataset_additionaldata(
rdataset,
check_related,
fctx);
fctx->attributes &=
~FCTX_ATTR_GLUING;
} else if (rdataset->type ==
dns_rdatatype_soa ||
rdataset->type ==
dns_rdatatype_nxt) {
/*
* SOA, SIG SOA, NXT, or SIG NXT.
*
* Only one SOA is allowed.
*/
if (soa_name != NULL &&
name != soa_name)
return (DNS_R_FORMERR);
soa_name = name;
negative_response = ISC_TRUE;
name->attributes |=
DNS_NAMEATTR_NCACHE;
rdataset->attributes |=
DNS_RDATASETATTR_NCACHE;
if (aa)
rdataset->trust =
dns_trust_authauthority;
else
rdataset->trust =
dns_trust_additional;
/*
* No additional data needs to be
* marked.
*/
}
}
}
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
if (result != ISC_R_NOMORE)
return (result);
}
/*
* Did we find anything?
*/
if (!negative_response && ns_name == NULL) {
/*
* Nope.
*/
if (oqname != NULL) {
/*
* We've already got a partial CNAME/DNAME chain,
* and haven't found else anything useful here, but
* no error has occurred since we have an answer.
*/
return (ISC_R_SUCCESS);
} else {
/*
* The responder is insane.
*/
return (DNS_R_FORMERR);
}
}
/*
* If we found both NS and SOA, they should be the same name.
*/
if (ns_name != NULL && soa_name != NULL) {
if (ns_name != soa_name)
return (DNS_R_FORMERR);
/*
* Don't cache the NS RRs.
*/
ns_name->attributes &= ~DNS_NAMEATTR_CACHE;
}
/*
* A negative response without an SOA isn't useful.
*/
if (negative_response && soa_name == NULL) {
if (oqname != NULL) {
/*
* But again, we don't care if we've got an answer
* already.
*/
return (ISC_R_SUCCESS);
} else
return (DNS_R_FORMERR);
}
/*
* Do we have a referral? (We only want to follow a referral if
* we're not following a chain.)
*/
if (!negative_response && ns_name != NULL && oqname == NULL) {
/*
* Set the current query domain to the referral name.
*/
INSIST(dns_name_countlabels(&fctx->domain) > 0);
dns_name_free(&fctx->domain, fctx->res->mctx);
dns_rdataset_disassociate(&fctx->nameservers);
dns_name_init(&fctx->domain, NULL);
result = dns_name_dup(ns_name, fctx->res->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
return (result);
return (DNS_R_DELEGATION);
}
return (ISC_R_SUCCESS);
}
static inline isc_result_t
answer_response(fetchctx_t *fctx) {
isc_result_t result;
dns_message_t *message;
dns_name_t *name, *qname, tname;
dns_rdataset_t *rdataset;
isc_boolean_t done, external, chaining, aa, found, want_chaining;
isc_boolean_t have_sig, have_answer;
unsigned int aflag;
dns_rdatatype_t type;
dns_fixedname_t dname;
message = fctx->rmessage;
/*
* Examine the answer section, marking those rdatasets which are
* part of the answer and should be cached.
*/
done = ISC_FALSE;
chaining = ISC_FALSE;
have_answer = ISC_FALSE;
have_sig = ISC_FALSE;
want_chaining = ISC_FALSE;
if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
aa = ISC_TRUE;
else
aa = ISC_FALSE;
qname = &fctx->name;
type = fctx->type;
result = dns_message_firstname(message, DNS_SECTION_ANSWER);
while (!done && result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_ANSWER, &name);
external = !dns_name_issubdomain(name, &fctx->domain);
if (dns_name_equal(name, qname)) {
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
found = ISC_FALSE;
want_chaining = ISC_FALSE;
aflag = 0;
if (rdataset->type == type ||
type == dns_rdatatype_any) {
/*
* We've found an ordinary answer.
*/
found = ISC_TRUE;
done = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWER;
} else if (rdataset->type == dns_rdatatype_sig
&& rdataset->covers == type) {
/*
* We've found a signature that
* covers the type we're looking for.
*/
found = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWERSIG;
} else if (rdataset->type ==
dns_rdatatype_cname) {
/*
* We're looking for something else,
* but we found a CNAME.
*
* Getting a CNAME response for some
* query types is an error.
*/
if (type == dns_rdatatype_sig ||
type == dns_rdatatype_key ||
type == dns_rdatatype_nxt)
return (DNS_R_FORMERR);
found = ISC_TRUE;
want_chaining = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWER;
result = cname_target(rdataset,
&tname);
if (result != ISC_R_SUCCESS)
return (result);
} else if (rdataset->type == dns_rdatatype_sig
&& rdataset->covers ==
dns_rdatatype_cname) {
/*
* We're looking for something else,
* but we found a SIG CNAME.
*/
found = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWERSIG;
}
if (found) {
/*
* We've found an answer to our
* question.
*/
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
rdataset->trust = dns_trust_answer;
if (!chaining) {
/*
* This data is "the" answer
* to our question only if
* we're not chaining (i.e.
* if we haven't followed
* a CNAME or DNAME).
*/
INSIST(!external);
if (aflag ==
DNS_RDATASETATTR_ANSWER)
have_answer = ISC_TRUE;
else
have_sig = ISC_TRUE;
name->attributes |=
DNS_NAMEATTR_ANSWER;
rdataset->attributes |= aflag;
if (aa)
rdataset->trust =
dns_trust_authanswer;
} else if (external) {
/*
* This data is outside of
* our query domain, and
* may only be cached if it
* comes from a secure zone
* and validates.
*/
rdataset->attributes |=
DNS_RDATASETATTR_EXTERNAL;
}
/*
* Mark any additional data related
* to this rdataset.
*/
(void)dns_rdataset_additionaldata(
rdataset,
check_related,
fctx);
/*
* A6 special cases...
*/
if (rdataset->type ==
dns_rdatatype_a6) {
check_related(fctx, name,
dns_rdatatype_a);
check_related(fctx, name,
dns_rdatatype_aaaa);
}
/*
* CNAME chaining.
*/
if (want_chaining) {
chaining = ISC_TRUE;
rdataset->attributes |=
DNS_RDATASETATTR_CHAINING;
qname = &tname;
}
}
/*
* We could add an "else" clause here and
* log that we're ignoring this rdataset.
*/
}
} else {
/*
* Look for a DNAME (or its SIG). Anything else is
* ignored.
*/
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
found = ISC_FALSE;
want_chaining = ISC_FALSE;
aflag = 0;
if (rdataset->type == dns_rdatatype_dname) {
/*
* We're looking for something else,
* but we found a DNAME.
*
* If we're not chaining, then the
* DNAME should not be external.
*/
if (!chaining && external)
return (DNS_R_FORMERR);
found = ISC_TRUE;
want_chaining = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWER;
result = dname_target(rdataset,
qname, name,
&dname);
if (result == ISC_R_NOSPACE) {
/*
* We can't construct the
* DNAME target. Do not
* try to continue.
*/
want_chaining = ISC_FALSE;
} else if (result != ISC_R_SUCCESS)
return (result);
} else if (rdataset->type == dns_rdatatype_sig
&& rdataset->covers ==
dns_rdatatype_dname) {
/*
* We've found a signature that
* covers the DNAME.
*/
found = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWERSIG;
}
if (found) {
/*
* We've found an answer to our
* question.
*/
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
rdataset->trust = dns_trust_answer;
if (!chaining) {
/*
* This data is "the" answer
* to our question only if
* we're not chaining.
*/
INSIST(!external);
name->attributes |=
DNS_NAMEATTR_ANSWER;
rdataset->attributes |= aflag;
if (aa)
rdataset->trust =
dns_trust_authanswer;
} else if (external) {
rdataset->attributes |=
DNS_RDATASETATTR_EXTERNAL;
}
/*
* DNAME chaining.
*/
if (want_chaining) {
chaining = ISC_TRUE;
rdataset->attributes |=
DNS_RDATASETATTR_CHAINING;
qname = dns_fixedname_name(
&dname);
}
}
}
}
result = dns_message_nextname(message, DNS_SECTION_ANSWER);
}
if (result != ISC_R_NOMORE)
return (result);
/*
* We should have found an answer.
*/
if (!have_answer)
return (DNS_R_FORMERR);
/*
* Did chaining end before we got the final answer?
*/
if (want_chaining) {
/*
* Yes. This may be a negative reply, so hand off
* authority section processing to the noanswer code.
* If it isn't a noanswer response, no harm will be
* done.
*/
return (noanswer_response(fctx, qname));
}
/*
* We didn't end with an incomplete chain, so the rcode should be
* "no error".
*/
if (message->rcode != dns_rcode_noerror)
return (DNS_R_FORMERR);
/*
* Examine the authority section (if there is one).
*
* We expect there to be only one owner name for all the rdatasets
* in this section, and we expect that it is not external.
*/
done = ISC_FALSE;
result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
while (!done && result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
external = !dns_name_issubdomain(name, &fctx->domain);
if (!external) {
/*
* We expect to find NS or SIG NS rdatasets, and
* nothing else.
*/
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (rdataset->type == dns_rdatatype_ns ||
(rdataset->type == dns_rdatatype_sig &&
rdataset->covers == dns_rdatatype_ns)) {
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
if (aa && !chaining)
rdataset->trust =
dns_trust_authauthority;
else
rdataset->trust =
dns_trust_additional;
/*
* Mark any additional data related
* to this rdataset.
*/
(void)dns_rdataset_additionaldata(
rdataset,
check_related,
fctx);
}
}
/*
* Since we've found a non-external name in the
* authority section, we should stop looking, even
* if we didn't find any NS or SIG NS.
*/
done = ISC_TRUE;
}
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
}
if (result != ISC_R_NOMORE)
return (result);
return (ISC_R_SUCCESS);
}
static void
resquery_response(isc_task_t *task, isc_event_t *event) {
isc_result_t result;
resquery_t *query = event->arg;
dns_dispatchevent_t *devent = (dns_dispatchevent_t *)event;
isc_boolean_t keep_trying, broken_server, get_nameservers;
dns_message_t *message;
fetchctx_t *fctx;
dns_rdatatype_t covers;
dns_name_t *fname;
dns_fixedname_t foundname;
isc_stdtime_t now;
REQUIRE(VALID_QUERY(query));
fctx = query->fctx;
REQUIRE(VALID_FCTX(fctx));
REQUIRE(event->type == DNS_EVENT_DISPATCH);
(void)task;
QTRACE("response");
(void)isc_timer_touch(fctx->timer);
keep_trying = ISC_FALSE;
broken_server = ISC_FALSE;
get_nameservers = ISC_FALSE;
covers = 0;
result = isc_stdtime_get(&now);
if (result != ISC_R_SUCCESS)
goto done;
message = fctx->rmessage;
message->querytsig = query->tsig;
message->tsigkey = query->tsigkey;
result = dns_message_parse(message, &devent->buffer, ISC_FALSE);
if (result != ISC_R_SUCCESS) {
switch (result) {
case DNS_R_FORMERR:
case DNS_R_UNEXPECTEDEND:
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
break;
case DNS_R_MOREDATA:
result = DNS_R_NOTIMPLEMENTED;
break;
}
goto done;
}
INSIST((message->flags & DNS_MESSAGEFLAG_QR) != 0);
/*
* INSIST() that the message comes from the place we sent it to,
* since the dispatch code should ensure this.
*
* INSIST() that the message id is correct (this should also be
* ensured by the dispatch code).
*/
/*
* Is it a query response?
*/
if (message->opcode != dns_opcode_query) {
/* XXXRTH Log */
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
goto done;
}
/*
* Is the remote server broken, or does it dislike us?
*/
if (message->rcode != dns_rcode_noerror &&
message->rcode != dns_rcode_nxdomain) {
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
/*
* XXXRTH If we want to catch a FORMERR caused by an EDNS0
* OPT RR, this is the place to do it.
*
* XXXRTH Need to deal with YXDOMAIN code.
*/
goto done;
}
/*
* Is the question the same as the one we asked?
*/
result = same_question(fctx);
if (result != ISC_R_SUCCESS) {
/* XXXRTH Log */
if (result == DNS_R_FORMERR)
keep_trying = ISC_TRUE;
goto done;
}
/*
* Did we get any answers?
*/
if (message->counts[DNS_SECTION_ANSWER] > 0 &&
(message->rcode == dns_rcode_noerror ||
message->rcode == dns_rcode_nxdomain)) {
/*
* We've got answers.
*/
result = answer_response(fctx);
if (result != ISC_R_SUCCESS) {
if (result == DNS_R_FORMERR)
keep_trying = ISC_TRUE;
goto done;
}
} else if (message->counts[DNS_SECTION_AUTHORITY] > 0) {
/*
* NXDOMAIN, NXRDATASET, or referral.
*/
result = noanswer_response(fctx, NULL);
if (result == DNS_R_DELEGATION) {
/*
* We don't have the answer, but we know a better
* place to look.
*/
get_nameservers = ISC_TRUE;
keep_trying = ISC_TRUE;
} else if (result == ISC_R_SUCCESS) {
if (message->rcode == dns_rcode_nxdomain)
covers = dns_rdatatype_any;
else
covers = fctx->type;
/*
* Cache any negative cache entries in the message.
* This may also cause work to be queued to the
* DNSSEC validator.
*/
result = ncache_message(fctx, covers, now);
if (result != ISC_R_SUCCESS)
goto done;
} else {
/*
* Something has gone wrong.
*/
if (result == DNS_R_FORMERR)
keep_trying = ISC_TRUE;
goto done;
}
} else {
/*
* The server is insane.
*/
/* XXXRTH Log */
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
goto done;
}
/*
* XXXRTH Explain this.
*/
query->tsig = NULL;
/*
* Cache the cacheable parts of the message. This may also cause
* work to be queued to the DNSSEC validator.
*/
result = cache_message(fctx);
done:
/*
* Give the event back to the dispatcher.
*/
dns_dispatch_freeevent(query->dispatch, query->dispentry, &devent);
/*
* XXXRTH Record round-trip statistics here. Note that 'result'
* MUST NOT be changed by this recording process.
*/
if (keep_trying) {
if (result == DNS_R_FORMERR)
broken_server = ISC_TRUE;
/*
* XXXRTH If we have a broken server at this point, we will
* decrease its 'goodness', possibly add a 'lame'
* entry, and maybe log a message.
*/
if (get_nameservers) {
dns_fixedname_init(&foundname);
fname = dns_fixedname_name(&foundname);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL);
return;
}
result = dns_view_findzonecut(fctx->res->view,
&fctx->domain,
fname,
now, 0, ISC_TRUE,
&fctx->nameservers,
NULL);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL);
return;
}
if (!dns_name_issubdomain(fname, &fctx->domain)) {
/*
* The best nameservers are now above our
* previous QDOMAIN.
*
* XXXRTH What should we do here?
*/
QTRACE("avoiding upward referral");
fctx_done(fctx, DNS_R_SERVFAIL);
return;
}
dns_name_free(&fctx->domain, fctx->res->mctx);
dns_name_init(&fctx->domain, NULL);
result = dns_name_dup(fname, fctx->res->mctx,
&fctx->domain);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL);
return;
}
fctx_freeaddresses(fctx);
}
/*
* Try again.
*/
fctx_try(fctx);
} else if (result == ISC_R_SUCCESS && !HAVE_ANSWER(fctx)) {
/*
* All has gone well so far, but we are waiting for the
* DNSSEC validator to validate the answer.
*/
fctx_cancelqueries(fctx);
result = fctx_stopidletimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result);
} else {
/*
* We're done.
*/
fctx_done(fctx, result);
}
}
/***
*** Resolver Methods
***/
static void
destroy(dns_resolver_t *res) {
unsigned int i;
REQUIRE(res->references == 0);
RTRACE("destroy");
isc_mutex_destroy(&res->lock);
for (i = 0; i < res->nbuckets; i++) {
INSIST(ISC_LIST_EMPTY(res->buckets[i].fctxs));
isc_task_shutdown(res->buckets[i].task);
isc_task_detach(&res->buckets[i].task);
isc_mutex_destroy(&res->buckets[i].lock);
}
isc_mem_put(res->mctx, res->buckets,
res->nbuckets * sizeof (fctxbucket_t));
if (res->dispatch4 != NULL)
dns_dispatch_detach(&res->dispatch4);
if (res->udpsocket4 != NULL)
isc_socket_detach(&res->udpsocket4);
if (res->dispatch6 != NULL)
dns_dispatch_detach(&res->dispatch6);
if (res->udpsocket6 != NULL)
isc_socket_detach(&res->udpsocket6);
res->magic = 0;
isc_mem_put(res->mctx, res, sizeof *res);
}
static void
empty_bucket(dns_resolver_t *res) {
isc_boolean_t need_destroy = ISC_FALSE;
RTRACE("empty_bucket");
LOCK(&res->lock);
INSIST(res->activebuckets > 0);
res->activebuckets--;
if (res->activebuckets == 0)
need_destroy = ISC_TRUE;
UNLOCK(&res->lock);
if (need_destroy)
destroy(res);
}
isc_result_t
dns_resolver_create(dns_view_t *view,
isc_taskmgr_t *taskmgr, unsigned int ntasks,
isc_socketmgr_t *socketmgr,
isc_timermgr_t *timermgr,
dns_dispatch_t *dispatch, dns_resolver_t **resp)
{
dns_resolver_t *res;
isc_result_t result = ISC_R_SUCCESS;
unsigned int i, buckets_created = 0;
in_port_t port = 5353;
REQUIRE(resp != NULL && *resp == NULL);
REQUIRE(ntasks > 0);
res = isc_mem_get(view->mctx, sizeof *res);
if (res == NULL)
return (ISC_R_NOMEMORY);
RTRACE("create");
res->mctx = view->mctx;
res->rdclass = view->rdclass;
res->socketmgr = socketmgr;
res->timermgr = timermgr;
res->view = view;
res->nbuckets = ntasks;
res->activebuckets = ntasks;
res->buckets = isc_mem_get(view->mctx,
ntasks * sizeof (fctxbucket_t));
if (res->buckets == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup_res;
}
for (i = 0; i < ntasks; i++) {
result = isc_mutex_init(&res->buckets[i].lock);
if (result != ISC_R_SUCCESS)
goto cleanup_buckets;
res->buckets[i].task = NULL;
result = isc_task_create(taskmgr, view->mctx, 0,
&res->buckets[i].task);
if (result != ISC_R_SUCCESS) {
isc_mutex_destroy(&res->buckets[i].lock);
goto cleanup_buckets;
}
ISC_LIST_INIT(res->buckets[i].fctxs);
res->buckets[i].exiting = ISC_FALSE;
buckets_created++;
}
/*
* IPv4 Dispatcher.
*/
res->dispatch4 = NULL;
res->udpsocket4 = NULL;
if (dispatch != NULL) {
dns_dispatch_attach(dispatch, &res->dispatch4);
} else if (isc_net_probeipv4() == ISC_R_SUCCESS) {
struct in_addr ina;
isc_sockaddr_t sa;
/*
* Create an IPv4 UDP socket and a dispatcher for it.
*/
result = isc_socket_create(socketmgr, AF_INET,
isc_sockettype_udp,
&res->udpsocket4);
if (result != ISC_R_SUCCESS)
goto cleanup_buckets;
result = ISC_R_UNEXPECTED;
while (result != ISC_R_SUCCESS && port < 5400) {
ina.s_addr = htonl(INADDR_ANY);
isc_sockaddr_fromin(&sa, &ina, port);
result = isc_socket_bind(res->udpsocket4, &sa);
if (result != ISC_R_SUCCESS)
port++;
}
if (result != ISC_R_SUCCESS) {
RTRACE("Could not open UDP port");
goto cleanup_buckets;
}
result = dns_dispatch_create(res->mctx, res->udpsocket4,
res->buckets[0].task, 4096,
50, 50, 14, &res->dispatch4);
if (result != ISC_R_SUCCESS)
goto cleanup_udpsocket4;
}
/*
* IPv6 Dispatcher.
*/
res->dispatch6 = NULL;
res->udpsocket6 = NULL;
if (isc_net_probeipv6() == ISC_R_SUCCESS) {
/*
* Create an IPv6 UDP socket and a dispatcher for it.
*/
result = isc_socket_create(socketmgr, AF_INET,
isc_sockettype_udp,
&res->udpsocket6);
if (result != ISC_R_SUCCESS)
goto cleanup_dispatch4;
result = dns_dispatch_create(res->mctx, res->udpsocket6,
res->buckets[0].task, 4096,
50, 50, 14, &res->dispatch6);
if (result != ISC_R_SUCCESS)
goto cleanup_udpsocket6;
}
res->references = 1;
res->exiting = ISC_FALSE;
result = isc_mutex_init(&res->lock);
if (result != ISC_R_SUCCESS)
goto cleanup_dispatch6;
res->magic = RES_MAGIC;
*resp = res;
return (ISC_R_SUCCESS);
cleanup_dispatch6:
if (res->dispatch6 != NULL)
dns_dispatch_detach(&res->dispatch6);
cleanup_udpsocket6:
if (res->udpsocket6 != NULL)
isc_socket_detach(&res->udpsocket6);
cleanup_dispatch4:
if (res->dispatch4 != NULL)
dns_dispatch_detach(&res->dispatch4);
cleanup_udpsocket4:
if (res->udpsocket4 != NULL)
isc_socket_detach(&res->udpsocket4);
cleanup_buckets:
for (i = 0; i < buckets_created; i++) {
(void)isc_mutex_destroy(&res->buckets[i].lock);
isc_task_shutdown(res->buckets[i].task);
isc_task_detach(&res->buckets[i].task);
}
isc_mem_put(view->mctx, res->buckets,
res->nbuckets * sizeof (fctxbucket_t));
cleanup_res:
isc_mem_put(view->mctx, res, sizeof *res);
return (result);
}
void
dns_resolver_attach(dns_resolver_t *source, dns_resolver_t **targetp) {
REQUIRE(VALID_RESOLVER(source));
REQUIRE(targetp != NULL && *targetp == NULL);
RRTRACE(source, "attach");
LOCK(&source->lock);
REQUIRE(!source->exiting);
INSIST(source->references > 0);
source->references++;
INSIST(source->references != 0);
UNLOCK(&source->lock);
*targetp = source;
}
void
dns_resolver_detach(dns_resolver_t **resp) {
dns_resolver_t *res;
isc_boolean_t need_destroy = ISC_FALSE;
unsigned int i;
REQUIRE(resp != NULL);
res = *resp;
REQUIRE(VALID_RESOLVER(res));
RTRACE("detach");
LOCK(&res->lock);
INSIST(res->references > 0);
res->references--;
if (res->references == 0) {
RTRACE("exiting");
res->exiting = ISC_TRUE;
for (i = 0; i < res->nbuckets; i++) {
/*
* XXXRTH Post shutdown events?
*/
LOCK(&res->buckets[i].lock);
if (res->udpsocket4 != NULL)
isc_socket_cancel(res->udpsocket4,
res->buckets[i].task,
ISC_SOCKCANCEL_ALL);
if (res->udpsocket6 != NULL)
isc_socket_cancel(res->udpsocket6,
res->buckets[i].task,
ISC_SOCKCANCEL_ALL);
res->buckets[i].exiting = ISC_TRUE;
if (ISC_LIST_EMPTY(res->buckets[i].fctxs)) {
INSIST(res->activebuckets > 0);
res->activebuckets--;
}
UNLOCK(&res->buckets[i].lock);
}
if (res->activebuckets == 0)
need_destroy = ISC_TRUE;
}
UNLOCK(&res->lock);
if (need_destroy)
destroy(res);
*resp = NULL;
}
static inline isc_boolean_t
fctx_match(fetchctx_t *fctx, dns_name_t *name, dns_rdatatype_t type,
unsigned int options)
{
if (fctx->type != type || fctx->options != options)
return (ISC_FALSE);
return (dns_name_equal(&fctx->name, name));
}
/*
* XXXRTH This routine takes an unconscionable number of arguments!
*
* Maybe caller should allocate an event and pass that in? Something must
* be done!
*/
isc_result_t
dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
dns_rdatatype_t type,
dns_name_t *domain, dns_rdataset_t *nameservers,
dns_forwarders_t *forwarders,
unsigned int options, isc_task_t *task,
isc_taskaction_t action, void *arg,
dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset,
dns_fetch_t **fetchp)
{
dns_fetch_t *fetch;
fetchctx_t *fctx = NULL;
isc_result_t result;
unsigned int bucketnum;
isc_boolean_t new_fctx = ISC_FALSE;
isc_event_t *event;
(void)forwarders;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(fetchp != NULL && *fetchp == NULL);
RTRACE("createfetch");
/* XXXRTH */
if ((options & DNS_FETCHOPT_TCP) != 0)
return (DNS_R_NOTIMPLEMENTED);
/*
* XXXRTH use a mempool?
*/
fetch = isc_mem_get(res->mctx, sizeof *fetch);
if (fetch == NULL)
return (ISC_R_NOMEMORY);
bucketnum = dns_name_hash(name, ISC_FALSE) % res->nbuckets;
LOCK(&res->buckets[bucketnum].lock);
if (res->buckets[bucketnum].exiting) {
result = ISC_R_SHUTTINGDOWN;
goto unlock;
}
if ((options & DNS_FETCHOPT_UNSHARED) == 0) {
for (fctx = ISC_LIST_HEAD(res->buckets[bucketnum].fctxs);
fctx != NULL;
fctx = ISC_LIST_NEXT(fctx, link)) {
if (fctx_match(fctx, name, type, options))
break;
}
}
if (fctx == NULL || fctx->state == fetchstate_done) {
fctx = NULL;
result = fctx_create(res, name, type, domain, nameservers,
options, bucketnum, &fctx);
if (result != ISC_R_SUCCESS)
goto unlock;
new_fctx = ISC_TRUE;
}
result = fctx_join(fctx, task, action, arg,
rdataset, sigrdataset, fetch);
if (new_fctx) {
if (result == ISC_R_SUCCESS) {
/*
* Launch this fctx.
*/
event = &fctx->control_event;
ISC_EVENT_INIT(event, sizeof *event, 0, NULL,
DNS_EVENT_FETCHCONTROL,
fctx_start, fctx, (void *)fctx_create,
NULL, NULL);
isc_task_send(res->buckets[bucketnum].task, &event);
} else {
/*
* We don't care about the result of fctx_destroy()
* since we know we're not exiting.
*/
(void)fctx_destroy(fctx);
}
}
unlock:
UNLOCK(&res->buckets[bucketnum].lock);
if (result == ISC_R_SUCCESS) {
FTRACE("created");
*fetchp = fetch;
} else
isc_mem_put(res->mctx, fetch, sizeof *fetch);
return (result);
}
void
dns_resolver_cancelfetch(dns_resolver_t *res, dns_fetch_t *fetch) {
fetchctx_t *fctx;
dns_fetchevent_t *event, *next_event;
isc_task_t *etask;
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
FTRACE("cancelfetch");
LOCK(&res->buckets[fctx->bucketnum].lock);
event = NULL;
if (fctx->state != fetchstate_done) {
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, link);
if (event->fetch == fetch) {
ISC_LIST_UNLINK(fctx->events, event,
link);
break;
}
}
}
if (event != NULL) {
etask = event->sender;
event->result = ISC_R_CANCELED;
isc_task_sendanddetach(&etask, (isc_event_t **)&event);
}
UNLOCK(&res->buckets[fctx->bucketnum].lock);
}
void
dns_resolver_destroyfetch(dns_resolver_t *res, dns_fetch_t **fetchp) {
dns_fetch_t *fetch;
dns_fetchevent_t *event, *next_event;
isc_event_t *cevent;
fetchctx_t *fctx;
REQUIRE(fetchp != NULL);
fetch = *fetchp;
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
FTRACE("destroyfetch");
LOCK(&res->buckets[fctx->bucketnum].lock);
/*
* Sanity check. The caller should have either gotten its
* fetchevent before trying to destroy the fetch.
*/
event = NULL;
if (fctx->state != fetchstate_done) {
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, link);
RUNTIME_CHECK(event->fetch != fetch);
}
}
INSIST(fctx->references > 0);
fctx->references--;
if (fctx->references == 0) {
/*
* No one cares about the result of this fetch anymore.
* Shut it down.
*/
fctx->exiting = ISC_TRUE;
/*
* Unless we're still initializing (in which case the
* control event is still outstanding), we need to post
* the control event to tell the fetch we want it to
* exit.
*/
if (fctx->state != fetchstate_init) {
cevent = &fctx->control_event;
isc_task_send(res->buckets[fctx->bucketnum].task,
&cevent);
}
}
UNLOCK(&res->buckets[fctx->bucketnum].lock);
isc_mem_put(res->mctx, fetch, sizeof *fetch);
*fetchp = NULL;
}