resolver.c revision b01cd0d5c7383c4201da1e3092938a855a4884b7
/*
* Copyright (C) 1999-2001 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.
*/
/* $Id: resolver.c,v 1.210 2001/03/13 05:49:58 marka Exp $ */
#include <config.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/util.h>
#include <dns/acl.h>
#include <dns/adb.h>
#include <dns/db.h>
#include <dns/dispatch.h>
#include <dns/events.h>
#include <dns/forward.h>
#include <dns/keytable.h>
#include <dns/log.h>
#include <dns/message.h>
#include <dns/ncache.h>
#include <dns/peer.h>
#include <dns/rdata.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/resolver.h>
#include <dns/result.h>
#include <dns/tsig.h>
#include <dns/validator.h>
#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(3), \
"res %p: %s", res, (m))
#define RRTRACE(r, m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"res %p: %s", (r), (m))
#define FCTXTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p: %s", fctx, (m))
#define FCTXTRACE2(m1, m2) \
isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p: %s %s", fctx, (m1), (m2))
#define FTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"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(3), \
"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
/*
* Maximum EDNS0 input packet size.
*/
#define SEND_BUFFER_SIZE 2048 /* XXXRTH Constant. */
/*
* This defines the maximum number of timeouts we will permit before we
* disable EDNS0 on the query.
*/
#define MAX_EDNS0_TIMEOUTS 3
typedef struct fetchctx fetchctx_t;
typedef struct query {
/* Locked by task event serialization. */
unsigned int magic;
fetchctx_t * fctx;
isc_mem_t * mctx;
dns_dispatchmgr_t * dispatchmgr;
dns_dispatch_t * dispatch;
dns_adbaddrinfo_t * addrinfo;
isc_socket_t * tcpsocket;
isc_time_t start;
dns_messageid_t id;
dns_dispentry_t * dispentry;
ISC_LINK(struct query) link;
isc_buffer_t buffer;
isc_buffer_t *tsig;
dns_tsigkey_t *tsigkey;
unsigned int options;
unsigned int attributes;
unsigned int sends;
unsigned char data[512];
} resquery_t;
#define QUERY_MAGIC 0x51212121U /* Q!!! */
#define VALID_QUERY(query) ((query) != NULL && \
(query)->magic == QUERY_MAGIC)
#define RESQUERY_ATTR_CONNECTING 0x01
#define RESQUERY_ATTR_CANCELED 0x02
#define RESQUERY_CONNECTING(q) (((q)->attributes & \
RESQUERY_ATTR_CONNECTING) != 0)
#define RESQUERY_CANCELED(q) (((q)->attributes & \
RESQUERY_ATTR_CANCELED) != 0)
#define RESQUERY_SENDING(q) ((q)->sends > 0)
typedef enum {
fetchstate_init = 0, /* Start event has not run yet. */
fetchstate_active,
fetchstate_done /* FETCHDONE events posted. */
} fetchstate;
struct fetchctx {
/* Not locked. */
unsigned int magic;
dns_resolver_t * res;
dns_name_t name;
dns_rdatatype_t type;
unsigned int options;
unsigned int bucketnum;
/* Locked by appropriate bucket lock. */
fetchstate state;
isc_boolean_t want_shutdown;
isc_boolean_t cloned;
unsigned int references;
isc_event_t control_event;
ISC_LINK(struct fetchctx) link;
ISC_LIST(dns_fetchevent_t) events;
/* Locked by task event serialization. */
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;
dns_adbfindlist_t finds;
dns_adbfind_t * find;
dns_adbaddrinfolist_t forwaddrs;
isc_sockaddrlist_t forwarders;
dns_fwdpolicy_t fwdpolicy;
isc_sockaddrlist_t bad;
ISC_LIST(dns_validator_t) validators;
/*
* The number of events we're waiting for.
*/
unsigned int pending;
/*
* The number of times we've "restarted" the current
* nameserver set. This acts as a failsafe to prevent
* us from pounding constantly on a particular set of
* servers that, for whatever reason, are not giving
* us useful responses, but are responding in such a
* way that they are not marked "bad".
*/
unsigned int restarts;
/*
* The number of timeouts that have occurred since we
* last successfully received a response packet. This
* is used for EDNS0 black hole detection.
*/
unsigned int timeouts;
};
#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 FCTX_ATTR_ADDRWAIT 0x04
#define FCTX_ATTR_SHUTTINGDOWN 0x08
#define FCTX_ATTR_WANTCACHE 0x10
#define FCTX_ATTR_WANTNCACHE 0x20
#define FCTX_ATTR_NEEDEDNS0 0x40
#define HAVE_ANSWER(f) (((f)->attributes & FCTX_ATTR_HAVEANSWER) != \
0)
#define GLUING(f) (((f)->attributes & FCTX_ATTR_GLUING) != \
0)
#define ADDRWAIT(f) (((f)->attributes & FCTX_ATTR_ADDRWAIT) != \
0)
#define SHUTTINGDOWN(f) (((f)->attributes & FCTX_ATTR_SHUTTINGDOWN) \
!= 0)
#define WANTCACHE(f) (((f)->attributes & FCTX_ATTR_WANTCACHE) != 0)
#define WANTNCACHE(f) (((f)->attributes & FCTX_ATTR_WANTNCACHE) != 0)
#define NEEDEDNS0(f) (((f)->attributes & FCTX_ATTR_NEEDEDNS0) != 0)
struct dns_fetch {
unsigned int magic;
fetchctx_t * 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;
isc_taskmgr_t * taskmgr;
dns_view_t * view;
isc_boolean_t frozen;
unsigned int options;
dns_dispatchmgr_t * dispatchmgr;
dns_dispatch_t * dispatchv4;
dns_dispatch_t * dispatchv6;
unsigned int nbuckets;
fctxbucket_t * buckets;
isc_uint32_t lame_ttl;
/* Locked by lock. */
unsigned int references;
isc_boolean_t exiting;
isc_eventlist_t whenshutdown;
unsigned int activebuckets;
isc_boolean_t priming;
dns_fetch_t * primefetch;
};
#define RES_MAGIC 0x52657321U /* Res! */
#define VALID_RESOLVER(res) ((res) != NULL && \
(res)->magic == RES_MAGIC)
/*
* Private addrinfo flags. These must not conflict with DNS_FETCHOPT_NOEDNS0,
* which we also use as an addrinfo flag.
*/
#define FCTX_ADDRINFO_MARK 0x0001
#define FCTX_ADDRINFO_FORWARDER 0x1000
#define UNMARKED(a) (((a)->flags & FCTX_ADDRINFO_MARK) \
== 0)
#define ISFORWARDER(a) (((a)->flags & \
FCTX_ADDRINFO_FORWARDER) != 0)
static void destroy(dns_resolver_t *res);
static void empty_bucket(dns_resolver_t *res);
static isc_result_t resquery_send(resquery_t *query);
static void resquery_response(isc_task_t *task, isc_event_t *event);
static void resquery_connected(isc_task_t *task, isc_event_t *event);
static void fctx_try(fetchctx_t *fctx);
static isc_boolean_t fctx_destroy(fetchctx_t *fctx);
static isc_result_t ncache_adderesult(dns_message_t *message,
dns_db_t *cache, dns_dbnode_t *node,
dns_rdatatype_t covers,
isc_stdtime_t now, dns_ttl_t maxttl,
dns_rdataset_t *ardataset,
isc_result_t *eresultp);
static inline isc_result_t
fctx_starttimer(fetchctx_t *fctx) {
/*
* Start the lifetime timer for fctx.
*
* This is also used for stopping the idle timer; in that
* case we must purge events already posted to ensure that
* no further idle events are delivered.
*/
return (isc_timer_reset(fctx->timer, isc_timertype_once,
&fctx->expires, NULL,
ISC_TRUE));
}
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 isc_result_t
fctx_startidletimer(fetchctx_t *fctx) {
/*
* Start the idle timer for fctx. The lifetime timer continues
* to be in effect.
*/
return (isc_timer_reset(fctx->timer, isc_timertype_once,
&fctx->expires, &fctx->interval,
ISC_FALSE));
}
/*
* Stopping the idle timer is equivalent to calling fctx_starttimer(), but
* we use fctx_stopidletimer for readability in the code below.
*/
#define fctx_stopidletimer fctx_starttimer
static inline void
resquery_destroy(resquery_t **queryp) {
resquery_t *query;
REQUIRE(queryp != NULL);
query = *queryp;
REQUIRE(!ISC_LINK_LINKED(query, link));
INSIST(query->tcpsocket == NULL);
query->magic = 0;
isc_mem_put(query->mctx, query, sizeof(*query));
*queryp = NULL;
}
static void
fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
isc_time_t *finish, isc_boolean_t no_response)
{
fetchctx_t *fctx;
resquery_t *query;
unsigned int rtt;
unsigned int factor;
query = *queryp;
fctx = query->fctx;
FCTXTRACE("cancelquery");
REQUIRE(!RESQUERY_CANCELED(query));
query->attributes |= RESQUERY_ATTR_CANCELED;
/*
* Should we update the RTT?
*/
if (finish != NULL || no_response) {
if (finish != NULL) {
/*
* We have both the start and finish times for this
* packet, so we can compute a real RTT.
*/
rtt = (unsigned int)isc_time_microdiff(finish,
&query->start);
factor = DNS_ADB_RTTADJDEFAULT;
} else {
/*
* We don't have an RTT for this query. Maybe the
* packet was lost, or maybe this server is very
* slow. We don't know. Increase the RTT.
*/
INSIST(no_response);
rtt = query->addrinfo->srtt +
(100000 * fctx->restarts);
if (rtt > 10000000)
rtt = 10000000;
/*
* Replace the current RTT with our value.
*/
factor = DNS_ADB_RTTADJREPLACE;
}
dns_adb_adjustsrtt(fctx->res->view->adb, query->addrinfo, rtt,
factor);
}
if (query->dispentry != NULL)
dns_dispatch_removeresponse(&query->dispentry, deventp);
ISC_LIST_UNLINK(fctx->queries, query, link);
if (query->tsig != NULL)
isc_buffer_free(&query->tsig);
if (query->tsigkey != NULL)
dns_tsigkey_detach(&query->tsigkey);
/*
* Check for any outstanding socket events. If they exist, cancel
* them and let the event handlers finish the cleanup. The resolver
* only needs to worry about managing the connect and send events;
* the dispatcher manages the recv events.
*/
if (RESQUERY_CONNECTING(query))
/*
* Cancel the connect.
*/
isc_socket_cancel(query->tcpsocket, NULL,
ISC_SOCKCANCEL_CONNECT);
else if (RESQUERY_SENDING(query))
/*
* Cancel the pending send.
*/
isc_socket_cancel(dns_dispatch_getsocket(query->dispatch),
NULL, ISC_SOCKCANCEL_SEND);
if (query->dispatch != NULL)
dns_dispatch_detach(&query->dispatch);
if (! (RESQUERY_CONNECTING(query) || RESQUERY_SENDING(query)))
/*
* It's safe to destroy the query now.
*/
resquery_destroy(&query);
}
static void
fctx_cancelqueries(fetchctx_t *fctx, isc_boolean_t no_response) {
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, NULL, no_response);
}
}
static void
fctx_cleanupfinds(fetchctx_t *fctx) {
dns_adbfind_t *find, *next_find;
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
for (find = ISC_LIST_HEAD(fctx->finds);
find != NULL;
find = next_find) {
next_find = ISC_LIST_NEXT(find, publink);
ISC_LIST_UNLINK(fctx->finds, find, publink);
dns_adb_destroyfind(&find);
}
fctx->find = NULL;
}
static void
fctx_cleanupforwaddrs(fetchctx_t *fctx) {
dns_adbaddrinfo_t *addr, *next_addr;
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
for (addr = ISC_LIST_HEAD(fctx->forwaddrs);
addr != NULL;
addr = next_addr) {
next_addr = ISC_LIST_NEXT(addr, publink);
ISC_LIST_UNLINK(fctx->forwaddrs, addr, publink);
dns_adb_freeaddrinfo(fctx->res->view->adb, &addr);
}
}
static inline void
fctx_stopeverything(fetchctx_t *fctx, isc_boolean_t no_response) {
FCTXTRACE("stopeverything");
fctx_cancelqueries(fctx, no_response);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
fctx_stoptimer(fctx);
}
static inline void
fctx_sendevents(fetchctx_t *fctx, isc_result_t result) {
dns_fetchevent_t *event, *next_event;
isc_task_t *task;
/*
* Caller must be holding the appropriate bucket lock.
*/
REQUIRE(fctx->state == fetchstate_done);
FCTXTRACE("sendevents");
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, ev_link);
ISC_LIST_UNLINK(fctx->events, event, ev_link);
task = event->ev_sender;
event->ev_sender = fctx;
if (!HAVE_ANSWER(fctx))
event->result = result;
INSIST(result != ISC_R_SUCCESS ||
dns_rdataset_isassociated(event->rdataset) ||
fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_sig);
isc_task_sendanddetach(&task, (isc_event_t **)&event);
}
}
static void
fctx_done(fetchctx_t *fctx, isc_result_t result) {
dns_resolver_t *res;
isc_boolean_t no_response;
FCTXTRACE("done");
res = fctx->res;
if (result == ISC_R_SUCCESS)
no_response = ISC_TRUE;
else
no_response = ISC_FALSE;
fctx_stopeverything(fctx, no_response);
LOCK(&res->buckets[fctx->bucketnum].lock);
fctx->state = fetchstate_done;
fctx_sendevents(fctx, result);
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->ev_arg;
REQUIRE(event->ev_type == ISC_SOCKEVENT_SENDDONE);
QTRACE("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!
*/
UNUSED(task);
INSIST(RESQUERY_SENDING(query));
query->sends--;
if (RESQUERY_CANCELED(query)) {
if (query->sends == 0) {
/*
* This query was canceled while the
* isc_socket_sendto() was in progress.
*/
if (query->tcpsocket != NULL)
isc_socket_detach(&query->tcpsocket);
resquery_destroy(&query);
}
} else if (sevent->result != ISC_R_SUCCESS)
fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
isc_event_free(&event);
}
static void
resquery_aborted(isc_task_t *task, isc_event_t *event) {
resquery_t *query = event->ev_arg;
REQUIRE(event->ev_type == DNS_EVENT_QUERYABORTED);
QTRACE("blackholed");
UNUSED(task);
/*
* Treat this as a "no response" to cause the RTT estimate to go up.
*/
fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
isc_event_free(&event);
}
static inline isc_result_t
fctx_addopt(dns_message_t *message) {
dns_rdataset_t *rdataset;
dns_rdatalist_t *rdatalist;
dns_rdata_t *rdata;
isc_result_t result;
rdatalist = NULL;
result = dns_message_gettemprdatalist(message, &rdatalist);
if (result != ISC_R_SUCCESS)
return (result);
rdata = NULL;
result = dns_message_gettemprdata(message, &rdata);
if (result != ISC_R_SUCCESS)
return (result);
rdataset = NULL;
result = dns_message_gettemprdataset(message, &rdataset);
if (result != ISC_R_SUCCESS)
return (result);
dns_rdataset_init(rdataset);
rdatalist->type = dns_rdatatype_opt;
rdatalist->covers = 0;
/*
* Set Maximum UDP buffer size.
*/
rdatalist->rdclass = SEND_BUFFER_SIZE;
/*
* Set EXTENDED-RCODE, VERSION, and Z to 0, and the DO bit to 1.
*/
rdatalist->ttl = DNS_MESSAGEEXTFLAG_DO;
/*
* No EDNS options.
*/
rdata->data = NULL;
rdata->length = 0;
rdata->rdclass = rdatalist->rdclass;
rdata->type = rdatalist->type;
rdata->flags = 0;
ISC_LIST_INIT(rdatalist->rdata);
ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
dns_rdatalist_tordataset(rdatalist, rdataset);
return (dns_message_setopt(message, rdataset));
}
static inline void
fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
unsigned int seconds;
/*
* We retry every 2 seconds the first two times through the address
* list, and then we do exponential back-off.
*/
if (fctx->restarts < 3)
seconds = 2;
else
seconds = (2 << (fctx->restarts - 1));
/*
* Double the round-trip time and convert to seconds.
*/
rtt /= 500000;
/*
* Always wait for at least the doubled round-trip time.
*/
if (seconds < rtt)
seconds = rtt;
/*
* But don't ever wait for more than 30 seconds.
*/
if (seconds > 30)
seconds = 30;
isc_interval_set(&fctx->interval, seconds, 0);
}
static isc_result_t
fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
unsigned int options)
{
dns_resolver_t *res;
isc_task_t *task;
isc_result_t result;
resquery_t *query;
FCTXTRACE("query");
res = fctx->res;
task = res->buckets[fctx->bucketnum].task;
fctx_setretryinterval(fctx, addrinfo->srtt);
result = fctx_startidletimer(fctx);
if (result != ISC_R_SUCCESS)
return (result);
dns_message_reset(fctx->rmessage, DNS_MESSAGE_INTENTPARSE);
query = isc_mem_get(res->mctx, sizeof *query);
if (query == NULL) {
result = ISC_R_NOMEMORY;
goto stop_idle_timer;
}
query->mctx = res->mctx;
query->options = options;
query->attributes = 0;
query->sends = 0;
/*
* Note that the caller MUST guarantee that 'addrinfo' will remain
* valid until this query is canceled.
*/
query->addrinfo = addrinfo;
result = isc_time_now(&query->start);
if (result != ISC_R_SUCCESS)
goto cleanup_query;
/*
* 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.
*/
query->dispatchmgr = res->dispatchmgr;
query->dispatch = NULL;
query->tcpsocket = NULL;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
isc_sockaddr_t addr;
int pf;
pf = isc_sockaddr_pf(&addrinfo->sockaddr);
switch (pf) {
case PF_INET:
result = dns_dispatch_getlocaladdress(res->dispatchv4,
&addr);
break;
case PF_INET6:
result = dns_dispatch_getlocaladdress(res->dispatchv6,
&addr);
break;
default:
result = ISC_R_NOTIMPLEMENTED;
break;
}
if (result != ISC_R_SUCCESS)
goto cleanup_query;
isc_sockaddr_setport(&addr, 0);
result = isc_socket_create(res->socketmgr, pf,
isc_sockettype_tcp,
&query->tcpsocket);
if (result != ISC_R_SUCCESS)
goto cleanup_query;
result = isc_socket_bind(query->tcpsocket, &addr);
if (result != ISC_R_SUCCESS)
goto cleanup_socket;
/*
* A dispatch will be created once the connect succeeds.
*/
} else {
switch (isc_sockaddr_pf(&addrinfo->sockaddr)) {
case PF_INET:
dns_dispatch_attach(res->dispatchv4, &query->dispatch);
break;
case PF_INET6:
dns_dispatch_attach(res->dispatchv6, &query->dispatch);
break;
default:
result = ISC_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);
}
query->dispentry = NULL;
query->fctx = fctx;
query->tsig = NULL;
query->tsigkey = NULL;
ISC_LINK_INIT(query, link);
query->magic = QUERY_MAGIC;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
/*
* Connect to the remote server.
*
* XXXRTH Should we attach to the socket?
*/
result = isc_socket_connect(query->tcpsocket,
&addrinfo->sockaddr, task,
resquery_connected, query);
if (result != ISC_R_SUCCESS)
goto cleanup_socket;
query->attributes |= RESQUERY_ATTR_CONNECTING;
QTRACE("connecting via TCP");
} else {
result = resquery_send(query);
if (result != ISC_R_SUCCESS)
goto cleanup_dispatch;
}
ISC_LIST_APPEND(fctx->queries, query, link);
return (ISC_R_SUCCESS);
cleanup_socket:
isc_socket_detach(&query->tcpsocket);
cleanup_dispatch:
if (query->dispatch != NULL)
dns_dispatch_detach(&query->dispatch);
cleanup_query:
query->magic = 0;
isc_mem_put(res->mctx, query, sizeof *query);
stop_idle_timer:
fctx_stopidletimer(fctx);
return (result);
}
static isc_result_t
resquery_send(resquery_t *query) {
fetchctx_t *fctx;
isc_result_t result;
dns_name_t *qname = NULL;
dns_rdataset_t *qrdataset = NULL;
isc_region_t r;
dns_resolver_t *res;
isc_task_t *task;
isc_socket_t *socket;
isc_buffer_t tcpbuffer;
isc_sockaddr_t *address;
isc_buffer_t *buffer;
isc_netaddr_t ipaddr;
dns_tsigkey_t *tsigkey = NULL;
dns_acl_t *blackhole;
dns_peer_t *peer = NULL;
isc_boolean_t useedns;
isc_boolean_t bogus;
isc_boolean_t aborted = ISC_FALSE;
dns_compress_t cctx;
isc_boolean_t cleanup_cctx = ISC_FALSE;
fctx = query->fctx;
QTRACE("send");
res = fctx->res;
task = res->buckets[fctx->bucketnum].task;
address = NULL;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
/*
* Reserve space for the TCP message length.
*/
isc_buffer_init(&tcpbuffer, query->data, sizeof(query->data));
isc_buffer_init(&query->buffer, query->data + 2,
sizeof(query->data) - 2);
buffer = &tcpbuffer;
} else {
isc_buffer_init(&query->buffer, query->data,
sizeof(query->data));
buffer = &query->buffer;
}
result = dns_message_gettempname(fctx->qmessage, &qname);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
result = dns_message_gettemprdataset(fctx->qmessage, &qrdataset);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
/*
* Get a query id from the dispatch.
*/
result = dns_dispatch_addresponse(query->dispatch,
&query->addrinfo->sockaddr,
task,
resquery_response,
query,
&query->id,
&query->dispentry);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
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);
qname = NULL;
qrdataset = NULL;
/*
* Set RD if the client has requested that we do a recursive query,
* or if we're sending to a forwarder.
*/
if ((query->options & DNS_FETCHOPT_RECURSIVE) != 0 ||
ISFORWARDER(query->addrinfo))
fctx->qmessage->flags |= DNS_MESSAGEFLAG_RD;
/*
* We don't have to set opcode because it defaults to query.
*/
fctx->qmessage->id = query->id;
/*
* Convert the question to wire format.
*/
result = dns_compress_init(&cctx, -1, fctx->res->mctx);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
cleanup_cctx = ISC_TRUE;
result = dns_message_renderbegin(fctx->qmessage, &cctx,
&query->buffer);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_rendersection(fctx->qmessage,
DNS_SECTION_QUESTION, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
peer = NULL;
isc_netaddr_fromsockaddr(&ipaddr, &query->addrinfo->sockaddr);
(void) dns_peerlist_peerbyaddr(fctx->res->view->peers, &ipaddr, &peer);
/*
* The ADB does not know about servers with "edns no". Check this,
* and then inform the ADB for future use.
*/
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0 &&
peer != NULL &&
dns_peer_getsupportedns(peer, &useedns) == ISC_R_SUCCESS &&
!useedns)
{
query->options |= DNS_FETCHOPT_NOEDNS0;
dns_adb_changeflags(fctx->res->view->adb,
query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
}
/*
* Use EDNS0, unless the caller doesn't want it, or we know that
* the remote server doesn't like it.
*/
if (fctx->timeouts >= MAX_EDNS0_TIMEOUTS &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
query->options |= DNS_FETCHOPT_NOEDNS0;
FCTXTRACE("too many timeouts, disabling EDNS0");
}
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0) {
result = fctx_addopt(fctx->qmessage);
if (result != ISC_R_SUCCESS) {
/*
* We couldn't add the OPT, but we'll press on.
* We're not using EDNS0, so set the NOEDNS0
* bit.
*/
query->options |= DNS_FETCHOPT_NOEDNS0;
}
} else {
/*
* We know this server doesn't like EDNS0, so we
* won't use it. Set the NOEDNS0 bit since we're
* not using EDNS0.
*/
query->options |= DNS_FETCHOPT_NOEDNS0;
}
}
/*
* If we need EDNS0 to do this query and aren't using it, we lose.
*/
if (NEEDEDNS0(fctx) && (query->options & DNS_FETCHOPT_NOEDNS0) != 0) {
result = DNS_R_SERVFAIL;
goto cleanup_message;
}
/*
* If we're using EDNS, set CD. CD and EDNS aren't really related,
* but if we send a non EDNS query, there's a chance the server
* won't understand CD either.
*/
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0)
fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
/*
* Add TSIG record tailored to the current recipient.
*/
result = dns_view_getpeertsig(fctx->res->view, &ipaddr, &tsigkey);
if (result != ISC_R_SUCCESS && result != ISC_R_NOTFOUND)
goto cleanup_message;
if (tsigkey != NULL) {
dns_message_settsigkey(fctx->qmessage, tsigkey);
dns_tsigkey_detach(&tsigkey);
}
result = dns_message_rendersection(fctx->qmessage,
DNS_SECTION_ADDITIONAL, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_renderend(fctx->qmessage);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
dns_compress_invalidate(&cctx);
cleanup_cctx = ISC_FALSE;
if (dns_message_gettsigkey(fctx->qmessage) != NULL) {
dns_tsigkey_attach(dns_message_gettsigkey(fctx->qmessage),
&query->tsigkey);
result = dns_message_getquerytsig(fctx->qmessage,
fctx->res->mctx,
&query->tsig);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
}
/*
* If using TCP, write the length of the message at the beginning
* of the buffer.
*/
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
isc_buffer_usedregion(&query->buffer, &r);
isc_buffer_putuint16(&tcpbuffer, (isc_uint16_t)r.length);
isc_buffer_add(&tcpbuffer, r.length);
}
/*
* We're now done with the query message.
*/
dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
socket = dns_dispatch_getsocket(query->dispatch);
/*
* Send the query!
*/
if ((query->options & DNS_FETCHOPT_TCP) == 0)
address = &query->addrinfo->sockaddr;
isc_buffer_usedregion(buffer, &r);
blackhole = dns_dispatchmgr_getblackhole(query->dispatchmgr);
if (blackhole != NULL) {
int match;
if (dns_acl_match(&ipaddr, NULL, blackhole,
NULL, &match, NULL) == ISC_R_SUCCESS &&
match > 0)
aborted = ISC_TRUE;
}
if (peer != NULL &&
dns_peer_getbogus(peer, &bogus) == ISC_R_SUCCESS &&
bogus)
aborted = ISC_TRUE;
if (aborted) {
isc_event_t *event;
event = isc_event_allocate(fctx->res->mctx, NULL,
DNS_EVENT_QUERYABORTED,
resquery_aborted, query,
sizeof(isc_event_t));
if (event == NULL)
return (ISC_R_NOMEMORY);
isc_task_send(task, &event);
result = ISC_R_SUCCESS;
goto cleanup_message;
}
/*
* XXXRTH Make sure we don't send to ourselves! We should probably
* prune out these addresses when we get them from the ADB.
*/
result = isc_socket_sendto(socket, &r, task, resquery_senddone,
query, address, NULL);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
query->sends++;
QTRACE("sent");
return (ISC_R_SUCCESS);
cleanup_message:
if (cleanup_cctx)
dns_compress_invalidate(&cctx);
dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
/*
* Stop the dispatcher from listening.
*/
dns_dispatch_removeresponse(&query->dispentry, NULL);
cleanup_temps:
if (qname != NULL)
dns_message_puttempname(fctx->qmessage, &qname);
if (qrdataset != NULL)
dns_message_puttemprdataset(fctx->qmessage, &qrdataset);
return (result);
}
static void
resquery_connected(isc_task_t *task, isc_event_t *event) {
isc_socketevent_t *sevent = (isc_socketevent_t *)event;
resquery_t *query = event->ev_arg;
isc_result_t result;
REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
REQUIRE(VALID_QUERY(query));
QTRACE("connected");
UNUSED(task);
/*
* XXXRTH
*
* Currently we don't wait for the connect event before retrying
* a query. This means that if we get really behind, we may end
* up doing extra work!
*/
query->attributes &= ~RESQUERY_ATTR_CONNECTING;
if (RESQUERY_CANCELED(query)) {
/*
* This query was canceled while the connect() was in
* progress.
*/
isc_socket_detach(&query->tcpsocket);
resquery_destroy(&query);
} else {
if (sevent->result == ISC_R_SUCCESS) {
unsigned int attrs;
/*
* We are connected. Create a dispatcher and
* send the query.
*/
attrs = 0;
attrs |= DNS_DISPATCHATTR_TCP;
attrs |= DNS_DISPATCHATTR_PRIVATE;
attrs |= DNS_DISPATCHATTR_CONNECTED;
if (isc_sockaddr_pf(&query->addrinfo->sockaddr) ==
AF_INET)
attrs |= DNS_DISPATCHATTR_IPV4;
else
attrs |= DNS_DISPATCHATTR_IPV6;
attrs |= DNS_DISPATCHATTR_MAKEQUERY;
result = dns_dispatch_createtcp(query->dispatchmgr,
query->tcpsocket,
query->fctx->res->taskmgr,
4096, 2, 1, 1, 3, attrs,
&query->dispatch);
/*
* Regardless of whether dns_dispatch_create()
* succeeded or not, we don't need our reference
* to the socket anymore.
*/
isc_socket_detach(&query->tcpsocket);
if (result == ISC_R_SUCCESS)
result = resquery_send(query);
if (result != ISC_R_SUCCESS) {
fetchctx_t *fctx = query->fctx;
fctx_cancelquery(&query, NULL, NULL,
ISC_FALSE);
fctx_done(fctx, result);
}
} else {
isc_socket_detach(&query->tcpsocket);
fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
}
}
isc_event_free(&event);
}
static void
fctx_finddone(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx;
dns_adbfind_t *find;
dns_resolver_t *res;
isc_boolean_t want_try = ISC_FALSE;
isc_boolean_t want_done = ISC_FALSE;
isc_boolean_t bucket_empty = ISC_FALSE;
unsigned int bucketnum;
find = event->ev_sender;
fctx = event->ev_arg;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
UNUSED(task);
FCTXTRACE("finddone");
INSIST(fctx->pending > 0);
fctx->pending--;
if (ADDRWAIT(fctx)) {
/*
* The fetch is waiting for a name to be found.
*/
INSIST(!SHUTTINGDOWN(fctx));
fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
if (event->ev_type == DNS_EVENT_ADBMOREADDRESSES)
want_try = ISC_TRUE;
else if (fctx->pending == 0) {
/*
* We've got nothing else to wait for and don't
* know the answer. There's nothing to do but
* fail the fctx.
*/
want_done = ISC_TRUE;
}
} else if (SHUTTINGDOWN(fctx) && fctx->pending == 0 &&
ISC_LIST_EMPTY(fctx->validators)) {
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
/*
* Note that we had to wait until we had the lock before
* looking at fctx->references.
*/
if (fctx->references == 0)
bucket_empty = fctx_destroy(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
}
isc_event_free(&event);
dns_adb_destroyfind(&find);
if (want_try)
fctx_try(fctx);
else if (want_done)
fctx_done(fctx, ISC_R_FAILURE);
else if (bucket_empty)
empty_bucket(res);
}
static inline isc_boolean_t
bad_server(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
for (sa = ISC_LIST_HEAD(fctx->bad);
sa != NULL;
sa = ISC_LIST_NEXT(sa, link)) {
if (isc_sockaddr_equal(sa, address))
return (ISC_TRUE);
}
return (ISC_FALSE);
}
static inline isc_boolean_t
mark_bad(fetchctx_t *fctx) {
dns_adbfind_t *curr;
dns_adbaddrinfo_t *addrinfo;
isc_boolean_t all_bad = ISC_TRUE;
/*
* Mark all known bad servers, so we don't try to talk to them
* again.
*/
/*
* Mark any bad nameservers.
*/
for (curr = ISC_LIST_HEAD(fctx->finds);
curr != NULL;
curr = ISC_LIST_NEXT(curr, publink)) {
for (addrinfo = ISC_LIST_HEAD(curr->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (bad_server(fctx, &addrinfo->sockaddr))
addrinfo->flags |= FCTX_ADDRINFO_MARK;
else
all_bad = ISC_FALSE;
}
}
/*
* Mark any bad forwarders.
*/
for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (bad_server(fctx, &addrinfo->sockaddr))
addrinfo->flags |= FCTX_ADDRINFO_MARK;
else
all_bad = ISC_FALSE;
}
return (all_bad);
}
static void
add_bad(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
if (bad_server(fctx, address)) {
/*
* We already know this server is bad.
*/
return;
}
FCTXTRACE("add_bad");
sa = isc_mem_get(fctx->res->mctx, sizeof *sa);
if (sa == NULL)
return;
*sa = *address;
ISC_LIST_INITANDAPPEND(fctx->bad, sa, link);
}
static void
sort_adbfind(dns_adbfind_t *find) {
dns_adbaddrinfo_t *best, *curr;
dns_adbaddrinfolist_t sorted;
/*
* Lame N^2 bubble sort.
*/
ISC_LIST_INIT(sorted);
while (!ISC_LIST_EMPTY(find->list)) {
best = ISC_LIST_HEAD(find->list);
curr = ISC_LIST_NEXT(best, publink);
while (curr != NULL) {
if (curr->srtt < best->srtt)
best = curr;
curr = ISC_LIST_NEXT(curr, publink);
}
ISC_LIST_UNLINK(find->list, best, publink);
ISC_LIST_APPEND(sorted, best, publink);
}
find->list = sorted;
}
static void
sort_finds(fetchctx_t *fctx) {
dns_adbfind_t *best, *curr;
dns_adbfindlist_t sorted;
dns_adbaddrinfo_t *addrinfo, *bestaddrinfo;
/*
* Lame N^2 bubble sort.
*/
ISC_LIST_INIT(sorted);
while (!ISC_LIST_EMPTY(fctx->finds)) {
best = ISC_LIST_HEAD(fctx->finds);
bestaddrinfo = ISC_LIST_HEAD(best->list);
INSIST(bestaddrinfo != NULL);
curr = ISC_LIST_NEXT(best, publink);
while (curr != NULL) {
addrinfo = ISC_LIST_HEAD(curr->list);
INSIST(addrinfo != NULL);
if (addrinfo->srtt < bestaddrinfo->srtt) {
best = curr;
bestaddrinfo = addrinfo;
}
curr = ISC_LIST_NEXT(curr, publink);
}
ISC_LIST_UNLINK(fctx->finds, best, publink);
ISC_LIST_APPEND(sorted, best, publink);
}
fctx->finds = sorted;
}
static isc_result_t
fctx_getaddresses(fetchctx_t *fctx) {
dns_rdata_t rdata = DNS_RDATA_INIT;
isc_result_t result;
dns_resolver_t *res;
isc_stdtime_t now;
dns_adbfind_t *find;
unsigned int stdoptions, options;
isc_sockaddr_t *sa;
dns_adbaddrinfo_t *ai;
isc_boolean_t pruned, all_bad;
dns_rdata_ns_t ns;
FCTXTRACE("getaddresses");
/*
* Don't pound on remote servers. (Failsafe!)
*/
fctx->restarts++;
if (fctx->restarts > 10) {
FCTXTRACE("too many restarts");
return (DNS_R_SERVFAIL);
}
res = fctx->res;
pruned = ISC_FALSE;
stdoptions = 0; /* Keep compiler happy. */
/*
* Forwarders.
*/
INSIST(ISC_LIST_EMPTY(fctx->forwaddrs));
/*
* If this fctx has forwarders, use them; otherwise use any
* selective forwarders specified in the view; otherwise use the
* resolver's forwarders (if any).
*/
sa = ISC_LIST_HEAD(fctx->forwarders);
if (sa == NULL) {
dns_forwarders_t *forwarders = NULL;
result = dns_fwdtable_find(fctx->res->view->fwdtable,
&fctx->name, &forwarders);
if (result == ISC_R_SUCCESS) {
sa = ISC_LIST_HEAD(forwarders->addrs);
fctx->fwdpolicy = forwarders->fwdpolicy;
}
}
while (sa != NULL) {
ai = NULL;
result = dns_adb_findaddrinfo(fctx->res->view->adb,
sa, &ai, 0); /* XXXMLG */
if (result == ISC_R_SUCCESS) {
ai->flags |= FCTX_ADDRINFO_FORWARDER;
ISC_LIST_APPEND(fctx->forwaddrs, ai, publink);
}
sa = ISC_LIST_NEXT(sa, link);
}
/*
* If the forwarding policy is "only", we don't need the addresses
* of the nameservers.
*/
if (fctx->fwdpolicy == dns_fwdpolicy_only)
goto out;
/*
* Normal nameservers.
*/
stdoptions = DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT;
if (fctx->restarts == 1) {
/*
* To avoid sending out a flood of queries likely to
* result in NXRRSET, we suppress fetches for address
* families we don't have the first time through,
* provided that we have addresses in some family we
* can use.
*
* We don't want to set this option all the time, since
* if fctx->restarts > 1, we've clearly been having trouble
* with the addresses we had, so getting more could help.
*/
stdoptions |= DNS_ADBFIND_AVOIDFETCHES;
}
if (res->dispatchv4 != NULL)
stdoptions |= DNS_ADBFIND_INET;
if (res->dispatchv6 != NULL)
stdoptions |= DNS_ADBFIND_INET6;
isc_stdtime_get(&now);
restart:
INSIST(ISC_LIST_EMPTY(fctx->finds));
result = dns_rdataset_first(&fctx->nameservers);
while (result == ISC_R_SUCCESS) {
dns_rdataset_current(&fctx->nameservers, &rdata);
/*
* Extract the name from the NS record.
*/
result = dns_rdata_tostruct(&rdata, &ns, NULL);
if (result != ISC_R_SUCCESS) {
dns_rdataset_next(&fctx->nameservers);
continue;
}
options = stdoptions;
/*
* If this name is a subdomain of the query domain, tell
* the ADB to start looking at "." if it doesn't know the
* address. This keeps us from getting stuck if the
* nameserver is beneath the zone cut and we don't know its
* address (e.g. because the A record has expired).
* By restarting from ".", we ensure that any missing glue
* will be reestablished.
*
* A further optimization would be to get the ADB to start
* looking at the most enclosing zone cut above fctx->domain.
* We don't expect this situation to happen very frequently,
* so we've chosen the simple solution.
*/
if (dns_name_issubdomain(&ns.name, &fctx->domain))
options |= DNS_ADBFIND_STARTATROOT;
options |= DNS_ADBFIND_GLUEOK;
options |= DNS_ADBFIND_HINTOK;
/*
* See what we know about this address.
*/
find = NULL;
result = dns_adb_createfind(res->view->adb,
res->buckets[fctx->bucketnum].task,
fctx_finddone, fctx, &ns.name,
&fctx->domain, options, now, NULL,
res->view->dstport, &find);
if (result != ISC_R_SUCCESS) {
if (result == DNS_R_ALIAS) {
/*
* XXXRTH Follow the CNAME/DNAME chain?
*/
dns_adb_destroyfind(&find);
}
} else if (!ISC_LIST_EMPTY(find->list)) {
/*
* We have at least some of the addresses for the
* name.
*/
INSIST((find->options & DNS_ADBFIND_WANTEVENT) == 0);
sort_adbfind(find);
ISC_LIST_APPEND(fctx->finds, find, publink);
} else {
/*
* We don't know any of the addresses for this
* name.
*/
if ((find->options & DNS_ADBFIND_WANTEVENT) != 0) {
/*
* We're looking for them and will get an
* event about it later.
*/
fctx->pending++;
} else {
/*
* And ADB isn't going to send us any events
* either. This find loses.
*/
if ((find->options & DNS_ADBFIND_LAMEPRUNED)
!= 0) {
/*
* The ADB pruned lame servers for
* this name. Remember that in case
* we get desperate later on.
*/
pruned = ISC_TRUE;
}
dns_adb_destroyfind(&find);
}
}
dns_rdata_reset(&rdata);
dns_rdata_freestruct(&ns);
result = dns_rdataset_next(&fctx->nameservers);
}
if (result != ISC_R_NOMORE)
return (result);
out:
/*
* Mark all known bad servers.
*/
all_bad = mark_bad(fctx);
/*
* How are we doing?
*/
if (all_bad) {
/*
* We've got no addresses.
*/
if (fctx->pending > 0) {
/*
* We're fetching the addresses, but don't have any
* yet. Tell the caller to wait for an answer.
*/
result = DNS_R_WAIT;
} else if (pruned) {
/*
* Some addresses were removed by lame pruning.
* Turn pruning off and try again.
*/
FCTXTRACE("restarting with returnlame");
INSIST((stdoptions & DNS_ADBFIND_RETURNLAME) == 0);
stdoptions |= DNS_ADBFIND_RETURNLAME;
pruned = ISC_FALSE;
fctx_cleanupfinds(fctx);
goto restart;
} else {
/*
* We've lost completely. We don't know any
* addresses, and the ADB has told us it can't get
* them.
*/
FCTXTRACE("no addresses");
result = ISC_R_FAILURE;
}
} else {
/*
* We've found some addresses. We might still be looking
* for more addresses.
*/
/*
* XXXRTH We could sort the forwaddrs here if the caller
* wants to use the forwaddrs in "best order" as
* opposed to "fixed order".
*/
sort_finds(fctx);
result = ISC_R_SUCCESS;
}
return (result);
}
static inline void
possibly_mark(fetchctx_t *fctx, dns_adbaddrinfo_t *addr)
{
isc_netaddr_t na;
char buf[ISC_NETADDR_FORMATSIZE];
isc_sockaddr_t *sa;
sa = &addr->sockaddr;
if (sa->type.sa.sa_family != AF_INET6)
return;
if (IN6_IS_ADDR_V4MAPPED(&sa->type.sin6.sin6_addr)) {
isc_netaddr_fromsockaddr(&na, sa);
isc_netaddr_format(&na, buf, sizeof buf);
addr->flags |= FCTX_ADDRINFO_MARK;
FCTXTRACE2("ignoring IPv6 mapped IPV4 address: ", buf);
} else if (IN6_IS_ADDR_V4COMPAT(&sa->type.sin6.sin6_addr)) {
isc_netaddr_fromsockaddr(&na, sa);
isc_netaddr_format(&na, buf, sizeof buf);
addr->flags |= FCTX_ADDRINFO_MARK;
FCTXTRACE2("ignoring IPv6 compatibility IPV4 address: ", buf);
}
}
static inline dns_adbaddrinfo_t *
fctx_nextaddress(fetchctx_t *fctx) {
dns_adbfind_t *find;
dns_adbaddrinfo_t *addrinfo;
/*
* Return the next untried address, if any.
*/
/*
* Find the first unmarked forwarder (if any).
*/
for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
possibly_mark(fctx, addrinfo);
if (UNMARKED(addrinfo)) {
addrinfo->flags |= FCTX_ADDRINFO_MARK;
fctx->find = NULL;
return (addrinfo);
}
}
/*
* No forwarders. Move to the next find.
*/
find = fctx->find;
if (find == NULL)
find = ISC_LIST_HEAD(fctx->finds);
else {
find = ISC_LIST_NEXT(find, publink);
if (find == NULL)
find = ISC_LIST_HEAD(fctx->finds);
}
/*
* Find the first unmarked addrinfo.
*/
addrinfo = NULL;
while (find != fctx->find) {
for (addrinfo = ISC_LIST_HEAD(find->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
possibly_mark(fctx, addrinfo);
if (UNMARKED(addrinfo)) {
addrinfo->flags |= FCTX_ADDRINFO_MARK;
break;
}
}
if (addrinfo != NULL)
break;
find = ISC_LIST_NEXT(find, publink);
if (find != fctx->find && find == NULL)
find = ISC_LIST_HEAD(fctx->finds);
}
fctx->find = find;
return (addrinfo);
}
static void
fctx_try(fetchctx_t *fctx) {
isc_result_t result;
dns_adbaddrinfo_t *addrinfo;
FCTXTRACE("try");
REQUIRE(!ADDRWAIT(fctx));
addrinfo = fctx_nextaddress(fctx);
if (addrinfo == NULL) {
/*
* We have no more addresses. Start over.
*/
fctx_cancelqueries(fctx, ISC_TRUE);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
result = fctx_getaddresses(fctx);
if (result == DNS_R_WAIT) {
/*
* Sleep waiting for addresses.
*/
FCTXTRACE("addrwait");
fctx->attributes |= FCTX_ATTR_ADDRWAIT;
return;
} else if (result != ISC_R_SUCCESS) {
/*
* Something bad happened.
*/
fctx_done(fctx, result);
return;
}
addrinfo = fctx_nextaddress(fctx);
/*
* While we may have addresses from the ADB, they
* might be bad ones. In this case, return SERVFAIL.
*/
if (addrinfo == NULL) {
fctx_done(fctx, DNS_R_SERVFAIL);
return;
}
}
result = fctx_query(fctx, addrinfo, fctx->options);
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;
isc_sockaddr_t *sa, *next_sa;
/*
* Caller must be holding the bucket lock.
*/
REQUIRE(VALID_FCTX(fctx));
REQUIRE(fctx->state == fetchstate_done ||
fctx->state == fetchstate_init);
REQUIRE(ISC_LIST_EMPTY(fctx->events));
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
REQUIRE(ISC_LIST_EMPTY(fctx->finds));
REQUIRE(fctx->pending == 0);
REQUIRE(ISC_LIST_EMPTY(fctx->validators));
REQUIRE(fctx->references == 0);
FCTXTRACE("destroy");
res = fctx->res;
bucketnum = fctx->bucketnum;
ISC_LIST_UNLINK(res->buckets[bucketnum].fctxs, fctx, link);
/*
* Free bad.
*/
for (sa = ISC_LIST_HEAD(fctx->bad);
sa != NULL;
sa = next_sa) {
next_sa = ISC_LIST_NEXT(sa, link);
ISC_LIST_UNLINK(fctx->bad, sa, link);
isc_mem_put(res->mctx, sa, sizeof *sa);
}
isc_timer_detach(&fctx->timer);
dns_message_destroy(&fctx->rmessage);
dns_message_destroy(&fctx->qmessage);
if (dns_name_countlabels(&fctx->domain) > 0)
dns_name_free(&fctx->domain, res->mctx);
if (dns_rdataset_isassociated(&fctx->nameservers))
dns_rdataset_disassociate(&fctx->nameservers);
dns_name_free(&fctx->name, 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->ev_arg;
REQUIRE(VALID_FCTX(fctx));
UNUSED(task);
FCTXTRACE("timeout");
if (event->ev_type == ISC_TIMEREVENT_LIFE) {
fctx_done(fctx, ISC_R_TIMEDOUT);
} else {
fctx->timeouts++;
/*
* We could cancel the running queries here, or we could let
* them keep going. Right now we choose the latter...
*/
fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
/*
* Our timer has triggered. Reestablish the fctx lifetime
* timer.
*/
fctx_starttimer(fctx);
/*
* Keep trying.
*/
fctx_try(fctx);
}
isc_event_free(&event);
}
static void
fctx_shutdown(fetchctx_t *fctx) {
isc_event_t *cevent;
/*
* Start the shutdown process for fctx, if it isn't already underway.
*/
FCTXTRACE("shutdown");
/*
* The caller must be holding the appropriate bucket lock.
*/
if (fctx->want_shutdown)
return;
fctx->want_shutdown = 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(fctx->res->buckets[fctx->bucketnum].task,
&cevent);
}
}
static void
fctx_doshutdown(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->ev_arg;
isc_boolean_t bucket_empty = ISC_FALSE;
dns_resolver_t *res;
unsigned int bucketnum;
dns_validator_t *validator;
REQUIRE(VALID_FCTX(fctx));
UNUSED(task);
res = fctx->res;
bucketnum = fctx->bucketnum;
FCTXTRACE("doshutdown");
fctx->attributes |= FCTX_ATTR_SHUTTINGDOWN;
/*
* An fctx that is shutting down is no longer in ADDRWAIT mode.
*/
fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
/*
* Cancel all pending validators. Note that this must be done
* without the bucket lock held, since that could cause deadlock.
*/
validator = ISC_LIST_HEAD(fctx->validators);
while (validator != NULL) {
dns_validator_cancel(validator);
validator = ISC_LIST_NEXT(validator, link);
}
LOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->state == fetchstate_active ||
fctx->state == fetchstate_done);
INSIST(fctx->want_shutdown);
if (fctx->state != fetchstate_done) {
fctx_stopeverything(fctx, ISC_FALSE);
fctx->state = fetchstate_done;
fctx_sendevents(fctx, ISC_R_CANCELED);
}
if (fctx->references == 0 && fctx->pending == 0 &&
ISC_LIST_EMPTY(fctx->validators))
bucket_empty = fctx_destroy(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty)
empty_bucket(res);
}
static void
fctx_start(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->ev_arg;
isc_boolean_t done = ISC_FALSE, bucket_empty = ISC_FALSE;
dns_resolver_t *res;
unsigned int bucketnum;
REQUIRE(VALID_FCTX(fctx));
UNUSED(task);
res = fctx->res;
bucketnum = fctx->bucketnum;
FCTXTRACE("start");
LOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->state == fetchstate_init);
if (fctx->want_shutdown) {
/*
* We haven't started this fctx yet, and we've been requested
* to shut it down.
*/
fctx->attributes |= FCTX_ATTR_SHUTTINGDOWN;
fctx->state = fetchstate_done;
fctx_sendevents(fctx, ISC_R_CANCELED);
/*
* Since we haven't started, we INSIST that we have no
* pending ADB finds and no pending validations.
*/
INSIST(fctx->pending == 0);
INSIST(ISC_LIST_EMPTY(fctx->validators));
if (fctx->references == 0) {
/*
* It's now safe to destroy this fctx.
*/
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_doshutdown, fctx,
NULL, NULL, NULL);
}
UNLOCK(&res->buckets[bucketnum].lock);
if (!done) {
/*
* All is well. Start working on the fetch.
*/
fctx_starttimer(fctx);
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) {
isc_task_detach(&clone);
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);
/*
* Make sure that we can store the sigrdataset in the
* first event if it is needed by any of the events.
*/
if (event->sigrdataset != NULL)
ISC_LIST_PREPEND(fctx->events, event, ev_link);
else
ISC_LIST_APPEND(fctx->events, event, ev_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;
dns_fixedname_t qdomain;
unsigned int findoptions = 0;
/*
* 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);
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->want_shutdown = ISC_FALSE;
fctx->cloned = ISC_FALSE;
ISC_LIST_INIT(fctx->queries);
ISC_LIST_INIT(fctx->finds);
ISC_LIST_INIT(fctx->forwaddrs);
ISC_LIST_INIT(fctx->forwarders);
fctx->fwdpolicy = dns_fwdpolicy_none;
ISC_LIST_INIT(fctx->bad);
ISC_LIST_INIT(fctx->validators);
fctx->find = NULL;
fctx->pending = 0;
fctx->restarts = 0;
fctx->timeouts = 0;
if (dns_name_requiresedns(name))
fctx->attributes = FCTX_ATTR_NEEDEDNS0;
else
fctx->attributes = 0;
if (domain == NULL) {
dns_forwarders_t *forwarders = NULL;
result = dns_fwdtable_find(fctx->res->view->fwdtable,
&fctx->name, &forwarders);
if (result == ISC_R_SUCCESS)
fctx->fwdpolicy = forwarders->fwdpolicy;
if (fctx->fwdpolicy != dns_fwdpolicy_only) {
/*
* The caller didn't supply a query domain and
* nameservers, and we're not in forward-only mode,
* so find the best nameservers to use.
*/
if (type == dns_rdatatype_key)
findoptions |= DNS_DBFIND_NOEXACT;
dns_fixedname_init(&qdomain);
result = dns_view_findzonecut(res->view, name,
dns_fixedname_name(&qdomain), 0,
findoptions, ISC_TRUE,
&fctx->nameservers,
NULL);
if (result != ISC_R_SUCCESS)
goto cleanup_name;
result = dns_name_dup(dns_fixedname_name(&qdomain),
res->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS) {
dns_rdataset_disassociate(&fctx->nameservers);
goto cleanup_name;
}
} else {
/*
* We're in forward-only mode. Set the query domain
* to ".".
*/
result = dns_name_dup(dns_rootname, res->mctx,
&fctx->domain);
if (result != ISC_R_SUCCESS)
goto cleanup_name;
}
} else {
result = dns_name_dup(domain, res->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
goto cleanup_name;
dns_rdataset_clone(nameservers, &fctx->nameservers);
}
INSIST(dns_name_issubdomain(&fctx->name, &fctx->domain));
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, 90, 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 = ISC_R_UNEXPECTED;
goto cleanup_rmessage;
}
/*
* Default retry interval initialization. We set the interval now
* mostly so it won't be uninitialized. It will be set to the
* correct value before a query is issued.
*/
isc_interval_set(&fctx->interval, 2, 0);
/*
* 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 = ISC_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_name_free(&fctx->domain, res->mctx);
if (dns_rdataset_isassociated(&fctx->nameservers))
dns_rdataset_disassociate(&fctx->nameservers);
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_boolean_t
is_lame(fetchctx_t *fctx) {
dns_message_t *message = fctx->rmessage;
dns_name_t *name;
dns_rdataset_t *rdataset;
isc_result_t result;
if (message->rcode != dns_rcode_noerror &&
message->rcode != dns_rcode_nxdomain)
return (ISC_FALSE);
if (message->counts[DNS_SECTION_ANSWER] != 0)
return (ISC_FALSE);
if (message->counts[DNS_SECTION_AUTHORITY] == 0)
return (ISC_FALSE);
result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
dns_namereln_t namereln;
int order;
unsigned int labels, bits;
if (rdataset->type != dns_rdatatype_ns)
continue;
namereln = dns_name_fullcompare(name, &fctx->domain,
&order, &labels, &bits);
if (namereln == dns_namereln_equal &&
(message->flags & DNS_MESSAGEFLAG_AA) != 0)
return (ISC_FALSE);
if (namereln == dns_namereln_subdomain)
return (ISC_FALSE);
return (ISC_TRUE);
}
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
}
return (ISC_FALSE);
}
static inline void
log_lame(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo) {
char namebuf[DNS_NAME_FORMATSIZE];
char domainbuf[DNS_NAME_FORMATSIZE];
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
isc_sockaddr_format(&addrinfo->sockaddr, addrbuf, sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"lame server resolving '%s' (in '%s'?): %s",
namebuf, domainbuf, addrbuf);
}
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.
*/
fctx->cloned = ISC_TRUE;
hevent = ISC_LIST_HEAD(fctx->events);
if (hevent == NULL)
return;
hname = dns_fixedname_name(&hevent->foundname);
for (event = ISC_LIST_NEXT(hevent, ev_link);
event != NULL;
event = ISC_LIST_NEXT(event, ev_link)) {
name = dns_fixedname_name(&event->foundname);
result = dns_name_copy(hname, 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);
INSIST(hevent->rdataset != NULL);
INSIST(event->rdataset != NULL);
if (dns_rdataset_isassociated(hevent->rdataset))
dns_rdataset_clone(hevent->rdataset, event->rdataset);
INSIST(! (hevent->sigrdataset == NULL &&
event->sigrdataset != NULL));
if (hevent->sigrdataset != NULL &&
dns_rdataset_isassociated(hevent->sigrdataset) &&
event->sigrdataset != NULL)
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)
/*
* Destroy '*fctx' if it is ready to be destroyed (i.e., if it has
* no references and is no longer waiting for any events). If this
* was the last fctx in the resolver, destroy the resolver.
*
* Requires:
* '*fctx' is shutting down.
*/
static void
maybe_destroy(fetchctx_t *fctx) {
unsigned int bucketnum;
isc_boolean_t bucket_empty = ISC_FALSE;
dns_resolver_t *res = fctx->res;
REQUIRE(SHUTTINGDOWN(fctx));
if (fctx->pending != 0 || !ISC_LIST_EMPTY(fctx->validators))
return;
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
if (fctx->references == 0)
bucket_empty = fctx_destroy(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty)
empty_bucket(res);
}
/*
* The validator has finished.
*/
static void
validated(isc_task_t *task, isc_event_t *event) {
isc_result_t result = ISC_R_SUCCESS;
isc_result_t eresult = ISC_R_SUCCESS;
isc_stdtime_t now;
fetchctx_t *fctx;
dns_validatorevent_t *vevent;
dns_fetchevent_t *hevent;
dns_rdataset_t *ardataset = NULL;
dns_rdataset_t *asigrdataset = NULL;
dns_dbnode_t *node = NULL;
isc_boolean_t negative;
isc_boolean_t chaining;
isc_boolean_t sentresponse;
isc_uint32_t ttl;
UNUSED(task); /* for now */
REQUIRE(event->ev_type == DNS_EVENT_VALIDATORDONE);
fctx = event->ev_arg;
REQUIRE(VALID_FCTX(fctx));
REQUIRE(!ISC_LIST_EMPTY(fctx->validators));
vevent = (dns_validatorevent_t *)event;
FCTXTRACE("received validation completion event");
ISC_LIST_UNLINK(fctx->validators, vevent->validator, link);
/*
* Destroy the validator early so that we can
* destroy the fctx if necessary.
*/
dns_validator_destroy(&vevent->validator);
negative = ISC_TF(vevent->rdataset == NULL);
sentresponse = ISC_TF((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0);
/*
* If shutting down, ignore the results. Check to see if we're
* done waiting for validator completions and ADB pending events; if
* so, destroy the fctx.
*/
if (SHUTTINGDOWN(fctx) && !sentresponse ) {
maybe_destroy(fctx);
goto cleanup_event;
}
/*
* If chaining, we need to make sure that the right result code is
* returned, and that the rdatasets are bound.
*/
if (vevent->result == ISC_R_SUCCESS &&
!negative &&
vevent->rdataset != NULL &&
CHAINING(vevent->rdataset))
{
if (vevent->rdataset->type == dns_rdatatype_cname)
eresult = DNS_R_CNAME;
else {
INSIST(vevent->rdataset->type == dns_rdatatype_dname);
eresult = DNS_R_DNAME;
}
chaining = ISC_TRUE;
} else
chaining = ISC_FALSE;
/*
* Either we're not shutting down, or we are shutting down but want
* to cache the result anyway (if this was a validation started by
* a query with cd set)
*/
hevent = ISC_LIST_HEAD(fctx->events);
if (hevent != NULL) {
if (!negative && !chaining &&
(fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_sig)) {
/*
* Don't bind rdatasets; the caller
* will iterate the node.
*/
} else {
ardataset = hevent->rdataset;
asigrdataset = hevent->sigrdataset;
}
}
if (vevent->result != ISC_R_SUCCESS) {
FCTXTRACE("validation failed");
if (vevent->rdataset != NULL) {
result = dns_db_findnode(fctx->res->view->cachedb,
vevent->name, ISC_TRUE,
&node);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
(void)dns_db_deleterdataset(fctx->res->view->cachedb,
node, NULL,
vevent->type, 0);
if (vevent->sigrdataset != NULL)
(void)dns_db_deleterdataset(
fctx->res->view->cachedb,
node, NULL,
dns_rdatatype_sig,
vevent->type);
}
result = vevent->result;
goto noanswer_response;
}
isc_stdtime_get(&now);
if (negative) {
dns_rdatatype_t covers;
FCTXTRACE("nonexistence validation OK");
if (fctx->rmessage->rcode == dns_rcode_nxdomain)
covers = dns_rdatatype_any;
else
covers = fctx->type;
result = dns_db_findnode(fctx->res->view->cachedb,
vevent->name, ISC_TRUE, &node);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
/*
* If we are asking for a SOA record set the cache time
* to zero to facilitate locating the containing zone of
* a arbitary zone.
*/
ttl = fctx->res->view->maxncachettl;
if (fctx->type == dns_rdatatype_soa &&
covers == dns_rdatatype_any)
ttl = 0;
result = ncache_adderesult(fctx->rmessage,
fctx->res->view->cachedb, node,
covers, now, ttl,
ardataset, &eresult);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
goto answer_response;
}
FCTXTRACE("validation OK");
/*
* The data was already cached as pending data.
* Re-cache it as secure and bind the cached
* rdatasets to the first event on the fetch
* event list.
*/
result = dns_db_findnode(fctx->res->view->cachedb,
vevent->name, ISC_TRUE, &node);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
result = dns_db_addrdataset(fctx->res->view->cachedb,
node, NULL, now,
vevent->rdataset, 0,
ardataset);
if (result != ISC_R_SUCCESS &&
result != DNS_R_UNCHANGED)
goto noanswer_response;
if (vevent->sigrdataset != NULL) {
result = dns_db_addrdataset(fctx->res->view->cachedb,
node, NULL, now,
vevent->sigrdataset, 0,
asigrdataset);
if (result != ISC_R_SUCCESS &&
result != DNS_R_UNCHANGED)
goto noanswer_response;
}
if (sentresponse) {
/*
* If we only deferred the destroy because we wanted to cache
* the data, destroy now.
*/
if (SHUTTINGDOWN(fctx))
maybe_destroy(fctx);
goto cleanup_event;
}
if (!ISC_LIST_EMPTY(fctx->validators)) {
INSIST(!negative);
INSIST(fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_sig);
/*
* Don't send a response yet - we have
* more rdatasets that still need to
* be validated.
*/
goto cleanup_event;
}
result = ISC_R_SUCCESS;
answer_response:
/*
* Respond with an answer, positive or negative,
* as opposed to an error. 'node' must be non-NULL.
*/
fctx->attributes |= FCTX_ATTR_HAVEANSWER;
if (hevent != NULL) {
hevent->result = eresult;
dns_name_copy(vevent->name,
dns_fixedname_name(&hevent->foundname), NULL);
dns_db_attach(fctx->res->view->cachedb, &hevent->db);
hevent->node = node;
node = NULL;
clone_results(fctx);
}
noanswer_response:
if (node != NULL)
dns_db_detachnode(fctx->res->view->cachedb, &node);
fctx_done(fctx, result);
cleanup_event:
isc_event_free(&event);
}
static inline isc_result_t
cache_name(fetchctx_t *fctx, dns_name_t *name, isc_stdtime_t now) {
dns_rdataset_t *rdataset, *sigrdataset;
dns_rdataset_t *addedrdataset, *ardataset, *asigrdataset;
dns_rdataset_t *valrdataset = NULL, *valsigrdataset = NULL;
dns_dbnode_t *node, **anodep;
dns_db_t **adbp;
dns_name_t *aname;
dns_resolver_t *res;
isc_boolean_t need_validation, secure_domain, have_answer;
isc_result_t result, eresult;
dns_fetchevent_t *event;
unsigned int options;
isc_task_t *task;
dns_validator_t *validator;
/*
* The appropriate bucket lock must be held.
*/
res = fctx->res;
need_validation = ISC_FALSE;
secure_domain = ISC_FALSE;
have_answer = ISC_FALSE;
eresult = ISC_R_SUCCESS;
task = res->buckets[fctx->bucketnum].task;
/*
* Is DNSSEC validation required for this name?
*/
result = dns_keytable_issecuredomain(res->view->secroots, name,
&secure_domain);
if (result != ISC_R_SUCCESS)
return (result);
if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
need_validation = ISC_FALSE;
else
need_validation = secure_domain;
adbp = NULL;
aname = NULL;
anodep = NULL;
ardataset = NULL;
asigrdataset = NULL;
event = NULL;
if ((name->attributes & DNS_NAMEATTR_ANSWER) != 0 &&
!need_validation) {
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_copy(name, aname, NULL);
if (result != ISC_R_SUCCESS)
return (result);
anodep = &event->node;
/*
* If this is an ANY or SIG query, we're not going
* to return any rdatasets, unless we encountered
* a CNAME or DNAME as "the answer". In this case,
* we're going to return DNS_R_CNAME or DNS_R_DNAME
* and we must set up the rdatasets.
*/
if ((fctx->type != dns_rdatatype_any &&
fctx->type != dns_rdatatype_sig) ||
(name->attributes & DNS_NAMEATTR_CHAINING) != 0) {
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;
/*
* Enforce the configure maximum cache TTL.
*/
if (rdataset->ttl > res->view->maxcachettl)
rdataset->ttl = res->view->maxcachettl;
/*
* If this rrset is in a secure domain, do DNSSEC validation
* for it, unless it is glue.
*/
if (secure_domain && rdataset->trust != dns_trust_glue) {
/*
* SIGs are validated as part of validating the
* type they cover.
*/
if (rdataset->type == dns_rdatatype_sig)
continue;
/*
* Find the SIG for this rdataset, if we have it.
*/
for (sigrdataset = ISC_LIST_HEAD(name->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
if (sigrdataset->type == dns_rdatatype_sig &&
sigrdataset->covers == rdataset->type)
break;
}
if (sigrdataset == NULL) {
if (!ANSWER(rdataset) && need_validation) {
/*
* Ignore non-answer rdatasets that
* are missing signatures.
*/
continue;
}
}
/*
* Normalize the rdataset and sigrdataset TTLs.
*/
if (sigrdataset != NULL) {
rdataset->ttl = ISC_MIN(rdataset->ttl,
sigrdataset->ttl);
sigrdataset->ttl = rdataset->ttl;
}
/*
* Cache this rdataset/sigrdataset pair as
* pending data.
*/
rdataset->trust = dns_trust_pending;
if (sigrdataset != NULL)
sigrdataset->trust = dns_trust_pending;
if (!need_validation)
addedrdataset = ardataset;
else
addedrdataset = NULL;
result = dns_db_addrdataset(res->view->cachedb,
node, NULL, now,
rdataset, 0,
addedrdataset);
if (result == DNS_R_UNCHANGED)
result = ISC_R_SUCCESS;
if (result != ISC_R_SUCCESS)
break;
if (sigrdataset != NULL) {
if (!need_validation)
addedrdataset = asigrdataset;
else
addedrdataset = NULL;
result = dns_db_addrdataset(res->view->cachedb,
node, NULL, now,
sigrdataset, 0,
addedrdataset);
if (result == DNS_R_UNCHANGED)
result = ISC_R_SUCCESS;
if (result != ISC_R_SUCCESS)
break;
} else if (!ANSWER(rdataset))
continue;
if (ANSWER(rdataset) && need_validation) {
if (fctx->type != dns_rdatatype_any &&
fctx->type != dns_rdatatype_sig) {
/*
* This is The Answer. We will
* validate it, but first we cache
* the rest of the response - it may
* contain useful keys.
*/
INSIST(valrdataset == NULL &&
valsigrdataset == NULL);
valrdataset = rdataset;
valsigrdataset = sigrdataset;
} else {
/*
* This is one of (potentially)
* multiple answers to an ANY
* or SIG query. To keep things
* simple, we just start the
* validator right away rather
* than caching first and
* having to remember which
* rdatasets needed validation.
*/
validator = NULL;
result = dns_validator_create(
res->view,
name,
rdataset->type,
rdataset,
sigrdataset,
fctx->rmessage,
0,
task,
validated,
fctx,
&validator);
if (result == ISC_R_SUCCESS)
ISC_LIST_APPEND(
fctx->validators,
validator, link);
}
}
} else if (!EXTERNAL(rdataset)) {
/*
* It's OK to cache this rdataset now.
*/
if (ANSWER(rdataset))
addedrdataset = ardataset;
else if (ANSWERSIG(rdataset))
addedrdataset = asigrdataset;
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;
}
}
if (rdataset->trust == dns_trust_glue) {
/*
* If the trust level is 'dns_trust_glue'
* then we are adding data from a referral
* we got while executing the search algorithm.
* New referral data always takes precedence
* over the existing cache contents.
*/
options = DNS_DBADD_FORCE;
} else
options = 0;
/*
* Now we can add the rdataset.
*/
result = dns_db_addrdataset(res->view->cachedb,
node, NULL, now,
rdataset,
options,
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 (valrdataset != NULL) {
validator = NULL;
result = dns_validator_create(res->view,
name,
fctx->type,
valrdataset,
valsigrdataset,
fctx->rmessage,
0,
task,
validated,
fctx,
&validator);
if (result == ISC_R_SUCCESS)
ISC_LIST_APPEND(fctx->validators, validator, link);
}
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;
node = NULL;
clone_results(fctx);
}
}
if (node != NULL)
dns_db_detachnode(res->view->cachedb, &node);
return (result);
}
static inline isc_result_t
cache_message(fetchctx_t *fctx, isc_stdtime_t now) {
isc_result_t result;
dns_section_t section;
dns_name_t *name;
FCTXTRACE("cache_message");
fctx->attributes &= ~FCTX_ATTR_WANTCACHE;
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);
}
/*
* Do what dns_ncache_add() does, and then compute an appropriate eresult.
*/
static isc_result_t
ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t maxttl,
dns_rdataset_t *ardataset,
isc_result_t *eresultp)
{
isc_result_t result;
result = dns_ncache_add(message, cache, node, covers, now,
maxttl, 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)
*eresultp = DNS_R_NCACHENXDOMAIN;
else
*eresultp = DNS_R_NCACHENXRRSET;
result = ISC_R_SUCCESS;
} 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.
*
* XXXRTH There's a CNAME/DNAME problem here.
*/
*eresultp = ISC_R_SUCCESS;
result = ISC_R_SUCCESS;
}
} else if (result == ISC_R_SUCCESS) {
if (covers == dns_rdatatype_any)
*eresultp = DNS_R_NCACHENXDOMAIN;
else
*eresultp = DNS_R_NCACHENXRRSET;
}
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, secure_domain;
dns_name_t *aname;
dns_fetchevent_t *event;
isc_uint32_t ttl;
FCTXTRACE("ncache_message");
fctx->attributes &= ~FCTX_ATTR_WANTNCACHE;
res = fctx->res;
need_validation = ISC_FALSE;
secure_domain = ISC_FALSE;
eresult = ISC_R_SUCCESS;
name = &fctx->name;
/*
* Is DNSSEC validation required for this name?
*/
result = dns_keytable_issecuredomain(res->view->secroots, name,
&secure_domain);
if (result != ISC_R_SUCCESS)
return (result);
if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
need_validation = ISC_FALSE;
else
need_validation = secure_domain;
if (secure_domain) {
/*
* Mark all rdatasets as pending.
*/
dns_rdataset_t *trdataset;
dns_name_t *tname;
result = dns_message_firstname(fctx->rmessage,
DNS_SECTION_AUTHORITY);
while (result == ISC_R_SUCCESS) {
tname = NULL;
dns_message_currentname(fctx->rmessage,
DNS_SECTION_AUTHORITY,
&tname);
for (trdataset = ISC_LIST_HEAD(tname->list);
trdataset != NULL;
trdataset = ISC_LIST_NEXT(trdataset, link))
trdataset->trust = dns_trust_pending;
result = dns_message_nextname(fctx->rmessage,
DNS_SECTION_AUTHORITY);
}
if (result != ISC_R_NOMORE)
return (result);
}
if (need_validation) {
/*
* Do negative response validation.
*/
dns_validator_t *validator = NULL;
isc_task_t *task = res->buckets[fctx->bucketnum].task;
result = dns_validator_create(res->view, name, fctx->type,
NULL, NULL,
fctx->rmessage, 0, task,
validated, fctx,
&validator);
if (result != ISC_R_SUCCESS)
return (result);
ISC_LIST_APPEND(fctx->validators, validator, link);
/*
* If validation is necessary, return now. Otherwise continue
* to process the message, letting the validation complete
* in its own good time.
*/
return (ISC_R_SUCCESS);
}
LOCK(&res->buckets[fctx->bucketnum].lock);
adbp = NULL;
aname = NULL;
anodep = NULL;
ardataset = NULL;
if (!HAVE_ANSWER(fctx)) {
event = ISC_LIST_HEAD(fctx->events);
if (event != NULL) {
adbp = &event->db;
aname = dns_fixedname_name(&event->foundname);
result = dns_name_copy(name, aname, NULL);
if (result != ISC_R_SUCCESS)
goto unlock;
anodep = &event->node;
ardataset = event->rdataset;
}
} else
event = NULL;
node = NULL;
result = dns_db_findnode(res->view->cachedb, name, ISC_TRUE,
&node);
if (result != ISC_R_SUCCESS)
goto unlock;
/*
* If we are asking for a SOA record set the cache time
* to zero to facilitate locating the containing zone of
* a arbitary zone.
*/
ttl = fctx->res->view->maxncachettl;
if (fctx->type == dns_rdatatype_soa &&
covers == dns_rdatatype_any)
ttl = 0;
result = ncache_adderesult(fctx->rmessage, res->view->cachedb, node,
covers, now, ttl, ardataset, &eresult);
if (result != ISC_R_SUCCESS)
goto unlock;
if (!HAVE_ANSWER(fctx)) {
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;
/*
* Glue with 0 TTL causes problems. We force the TTL to
* 1 second to prevent this.
*/
if (rdataset->ttl == 0)
rdataset->ttl = 1;
} 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 = ISC_TF(!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 = DNS_RDATA_INIT;
dns_rdata_cname_t cname;
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS)
return (result);
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_tostruct(&rdata, &cname, NULL);
if (result != ISC_R_SUCCESS)
return (result);
dns_name_init(tname, NULL);
dns_name_clone(&cname.cname, tname);
dns_rdata_freestruct(&cname);
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 = DNS_RDATA_INIT;
unsigned int nlabels, nbits;
int order;
dns_namereln_t namereln;
dns_rdata_dname_t dname;
dns_fixedname_t prefix;
/*
* Get the target name of the DNAME.
*/
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS)
return (result);
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_tostruct(&rdata, &dname, NULL);
if (result != ISC_R_SUCCESS)
return (result);
/*
* Get the prefix of qname.
*/
namereln = dns_name_fullcompare(qname, oname, &order, &nlabels,
&nbits);
if (namereln != dns_namereln_subdomain) {
dns_rdata_freestruct(&dname);
return (DNS_R_FORMERR);
}
dns_fixedname_init(&prefix);
result = dns_name_split(qname, nlabels, nbits,
dns_fixedname_name(&prefix), NULL);
if (result != ISC_R_SUCCESS) {
dns_rdata_freestruct(&dname);
return (result);
}
dns_fixedname_init(fixeddname);
result = dns_name_concatenate(dns_fixedname_name(&prefix),
&dname.dname,
dns_fixedname_name(fixeddname), NULL);
dns_rdata_freestruct(&dname);
return (result);
}
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, *ns_rdataset;
isc_boolean_t done, aa, negative_response;
dns_rdatatype_t type;
FCTXTRACE("noanswer_response");
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;
/*
* If the current qname is not a subdomain of the query
* domain, there's no point in looking at the authority
* section without doing DNSSEC validation.
*
* Until we do that validation, we'll just return success
* in this case.
*/
if (!dns_name_issubdomain(qname, &fctx->domain))
return (ISC_R_SUCCESS);
}
/*
* We have to figure out if this is a negative response, or a
* referral.
*/
/*
* Sometimes we can tell if its a negative response by looking at
* the message header.
*/
negative_response = ISC_FALSE;
if (message->rcode == dns_rcode_nxdomain ||
(message->counts[DNS_SECTION_ANSWER] == 0 &&
message->counts[DNS_SECTION_AUTHORITY] == 0))
negative_response = ISC_TRUE;
/*
* Process the authority section.
*/
done = ISC_FALSE;
ns_name = NULL;
ns_rdataset = 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 (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;
ns_rdataset = rdataset;
} else if (type == dns_rdatatype_soa ||
type == dns_rdatatype_nxt) {
/*
* SOA, SIG SOA, NXT, or SIG NXT.
*
* Only one SOA is allowed.
*/
if (rdataset->type ==
dns_rdatatype_soa) {
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)
break;
else if (result != ISC_R_SUCCESS)
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 && ns_name != soa_name)
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) {
/*
* We already know ns_name is a subdomain of fctx->domain.
* If ns_name is equal to fctx->domain, we're not making
* progress. We return DNS_R_FORMERR so that we'll keep
* keep trying other servers.
*/
if (dns_name_equal(ns_name, &fctx->domain))
return (DNS_R_FORMERR);
/*
* If the referral name is not a parent of the query
* name, consider the responder insane.
*/
if (! dns_name_issubdomain(&fctx->name, ns_name)) {
FCTXTRACE("referral to non-parent");
return (DNS_R_FORMERR);
}
/*
* Mark any additional data related to this rdataset.
* It's important that we do this before we change the
* query domain.
*/
INSIST(ns_rdataset != NULL);
fctx->attributes |= FCTX_ATTR_GLUING;
(void)dns_rdataset_additionaldata(ns_rdataset, check_related,
fctx);
fctx->attributes &= ~FCTX_ATTR_GLUING;
/*
* NS rdatasets with 0 TTL cause problems.
* dns_view_findzonecut() will not find them when we
* try to follow the referral, and we'll SERVFAIL
* because the best nameservers are now above QDOMAIN.
* We force the TTL to 1 second to prevent this.
*/
if (ns_rdataset->ttl == 0)
ns_rdataset->ttl = 1;
/*
* Set the current query domain to the referral name.
*
* XXXRTH We should check if we're in forward-only mode, and
* if so we should bail out.
*/
INSIST(dns_name_countlabels(&fctx->domain) > 0);
dns_name_free(&fctx->domain, fctx->res->mctx);
if (dns_rdataset_isassociated(&fctx->nameservers))
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);
fctx->attributes |= FCTX_ATTR_WANTCACHE;
return (DNS_R_DELEGATION);
}
/*
* Since we're not doing a referral, we don't want to cache any
* NS RRs we may have found.
*/
if (ns_name != NULL)
ns_name->attributes &= ~DNS_NAMEATTR_CACHE;
if (negative_response)
fctx->attributes |= FCTX_ATTR_WANTNCACHE;
return (ISC_R_SUCCESS);
}
static 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_answer, found_cname, found_type;
unsigned int aflag;
dns_rdatatype_t type;
dns_fixedname_t dname, fqname;
FCTXTRACE("answer_response");
message = fctx->rmessage;
/*
* Examine the answer section, marking those rdatasets which are
* part of the answer and should be cached.
*/
done = ISC_FALSE;
found_cname = ISC_FALSE;
found_type = ISC_FALSE;
chaining = ISC_FALSE;
have_answer = 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 = ISC_TF(!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 && !found_cname) {
/*
* We've found an ordinary answer.
*/
found = ISC_TRUE;
found_type = ISC_TRUE;
done = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWER;
} else if (type == dns_rdatatype_any) {
/*
* We've found an answer matching
* an ANY query. There may be
* more.
*/
found = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWER;
} else if (rdataset->type == dns_rdatatype_sig
&& rdataset->covers == type
&& !found_cname) {
/*
* We've found a signature that
* covers the type we're looking for.
*/
found = ISC_TRUE;
found_type = ISC_TRUE;
aflag = DNS_RDATASETATTR_ANSWERSIG;
} else if (rdataset->type ==
dns_rdatatype_cname
&& !found_type) {
/*
* 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;
found_cname = 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
&& !found_type) {
/*
* We're looking for something else,
* but we found a SIG CNAME.
*/
found = ISC_TRUE;
found_cname = 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;
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);
/*
* CNAME chaining.
*/
if (want_chaining) {
chaining = ISC_TRUE;
name->attributes |=
DNS_NAMEATTR_CHAINING;
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);
if (aflag ==
DNS_RDATASETATTR_ANSWER)
have_answer = ISC_TRUE;
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) {
/*
* Copy the the dname into the
* qname fixed name.
*
* Although we check for
* failure of the copy
* operation, in practice it
* should never fail since
* we already know that the
* result fits in a fixedname.
*/
dns_fixedname_init(&fqname);
result = dns_name_copy(
dns_fixedname_name(&dname),
dns_fixedname_name(&fqname),
NULL);
if (result != ISC_R_SUCCESS)
return (result);
chaining = ISC_TRUE;
name->attributes |=
DNS_NAMEATTR_CHAINING;
rdataset->attributes |=
DNS_RDATASETATTR_CHAINING;
qname = dns_fixedname_name(
&fqname);
}
}
}
}
result = dns_message_nextname(message, DNS_SECTION_ANSWER);
}
if (result == ISC_R_NOMORE)
result = ISC_R_SUCCESS;
if (result != ISC_R_SUCCESS)
return (result);
/*
* We should have found an answer.
*/
if (!have_answer)
return (DNS_R_FORMERR);
/*
* This response is now potentially cacheable.
*/
fctx->attributes |= FCTX_ATTR_WANTCACHE;
/*
* 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 = ISC_TF(!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)
result = ISC_R_SUCCESS;
return (result);
}
static void
resquery_response(isc_task_t *task, isc_event_t *event) {
isc_result_t result;
resquery_t *query = event->ev_arg;
dns_dispatchevent_t *devent = (dns_dispatchevent_t *)event;
isc_boolean_t keep_trying, broken_server, get_nameservers, resend;
isc_boolean_t truncated;
dns_message_t *message;
fetchctx_t *fctx;
dns_name_t *fname;
dns_fixedname_t foundname;
isc_stdtime_t now;
isc_time_t tnow, *finish;
dns_adbaddrinfo_t *addrinfo;
unsigned int options;
REQUIRE(VALID_QUERY(query));
fctx = query->fctx;
options = query->options;
REQUIRE(VALID_FCTX(fctx));
REQUIRE(event->ev_type == DNS_EVENT_DISPATCH);
UNUSED(task);
QTRACE("response");
(void)isc_timer_touch(fctx->timer);
keep_trying = ISC_FALSE;
broken_server = ISC_FALSE;
get_nameservers = ISC_FALSE;
resend = ISC_FALSE;
truncated = ISC_FALSE;
finish = NULL;
fctx->timeouts = 0;
/*
* XXXRTH We should really get the current time just once. We
* need a routine to convert from an isc_time_t to an
* isc_stdtime_t.
*/
result = isc_time_now(&tnow);
if (result != ISC_R_SUCCESS)
goto done;
finish = &tnow;
isc_stdtime_get(&now);
/*
* Did the dispatcher have a problem?
*/
if (devent->result != ISC_R_SUCCESS) {
if (devent->result == ISC_R_EOF &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* The problem might be that they
* don't understand EDNS0. Turn it
* off and try again.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = ISC_TRUE;
/*
* Remember that they don't like EDNS0.
*/
dns_adb_changeflags(fctx->res->view->adb,
query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
} else {
/*
* There's no hope for this query.
*/
keep_trying = ISC_TRUE;
}
goto done;
}
message = fctx->rmessage;
if (query->tsig != NULL) {
result = dns_message_setquerytsig(message, query->tsig);
if (result != ISC_R_SUCCESS)
goto done;
}
if (query->tsigkey) {
result = dns_message_settsigkey(message, query->tsigkey);
if (result != ISC_R_SUCCESS)
goto done;
}
result = dns_message_parse(message, &devent->buffer, 0);
if (result != ISC_R_SUCCESS) {
switch (result) {
case ISC_R_UNEXPECTEDEND:
if (!message->question_ok ||
(message->flags & DNS_MESSAGEFLAG_TC) == 0 ||
(options & DNS_FETCHOPT_TCP) != 0) {
/*
* Either the message ended prematurely,
* and/or wasn't marked as being truncated,
* and/or this is a response to a query we
* sent over TCP. In all of these cases,
* something is wrong with the remote
* server and we don't want to retry using
* TCP.
*/
if ((query->options & DNS_FETCHOPT_NOEDNS0)
== 0) {
/*
* The problem might be that they
* don't understand EDNS0. Turn it
* off and try again.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = ISC_TRUE;
/*
* Remember that they don't like EDNS0.
*/
dns_adb_changeflags(
fctx->res->view->adb,
query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
} else {
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
}
goto done;
}
/*
* We defer retrying via TCP for a bit so we can
* check out this message further.
*/
truncated = ISC_TRUE;
break;
case DNS_R_FORMERR:
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* The problem might be that they
* don't understand EDNS0. Turn it
* off and try again.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = ISC_TRUE;
/*
* Remember that they don't like EDNS0.
*/
dns_adb_changeflags(fctx->res->view->adb,
query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
} else {
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
}
goto done;
case DNS_R_MOREDATA:
result = ISC_R_NOTIMPLEMENTED;
goto done;
default:
/*
* Something bad has happened.
*/
goto done;
}
}
/*
* If the message is signed, check the signature. If not, this
* returns success anyway.
*/
result = dns_message_checksig(message, fctx->res->view);
if (result != ISC_R_SUCCESS)
goto done;
/*
* The dispatcher should ensure we only get responses with QR set.
*/
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).
*/
/*
* Deal with truncated responses by retrying using TCP.
*/
if ((message->flags & DNS_MESSAGEFLAG_TC) != 0)
truncated = ISC_TRUE;
if (truncated) {
if ((options & DNS_FETCHOPT_TCP) != 0) {
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
} else {
options |= DNS_FETCHOPT_TCP;
resend = ISC_TRUE;
}
goto done;
}
/*
* 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) {
if (message->rcode == dns_rcode_formerr) {
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* It's very likely they don't like EDNS0.
*
* XXXRTH We should check if the question
* we're asking requires EDNS0, and
* if so, we should bail out.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = ISC_TRUE;
/*
* Remember that they don't like EDNS0.
*/
dns_adb_changeflags(fctx->res->view->adb,
query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
} else if (ISFORWARDER(query->addrinfo)) {
/*
* This forwarder doesn't understand us,
* but other forwarders might. Keep trying.
*/
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
} else {
/*
* The server doesn't understand us. Since
* all servers for a zone need similar
* capabilities, we assume that we will get
* FORMERR from all servers, and thus we
* cannot make any more progress with this
* fetch.
*/
result = DNS_R_FORMERR;
}
} else if (message->rcode == dns_rcode_yxdomain) {
/*
* DNAME mapping failed because the new name
* was too long. There's no chance of success
* for this fetch.
*/
result = DNS_R_YXDOMAIN;
} else {
/*
* XXXRTH log.
*/
broken_server = ISC_TRUE;
keep_trying = ISC_TRUE;
}
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;
}
/*
* Is the server lame?
*/
if (fctx->res->lame_ttl != 0 && !ISFORWARDER(query->addrinfo) &&
is_lame(fctx)) {
log_lame(fctx, query->addrinfo);
dns_adb_marklame(fctx->res->view->adb, query->addrinfo,
&fctx->domain, now + fctx->res->lame_ttl);
broken_server = ISC_TRUE;
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 ||
message->rcode == dns_rcode_noerror ||
message->rcode == dns_rcode_nxdomain) {
/*
* 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;
/*
* We have a new set of name servers, and it
* has not experienced any restarts yet.
*/
fctx->restarts = 0;
result = ISC_R_SUCCESS;
} else if (result != ISC_R_SUCCESS) {
/*
* 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;
}
/*
* Cache the cacheable parts of the message. This may also cause
* work to be queued to the DNSSEC validator.
*/
if (WANTCACHE(fctx)) {
result = cache_message(fctx, now);
if (result != ISC_R_SUCCESS)
goto done;
}
/*
* Ncache the negatively cacheable parts of the message. This may
* also cause work to be queued to the DNSSEC validator.
*/
if (WANTNCACHE(fctx)) {
dns_rdatatype_t covers;
if (message->rcode == dns_rcode_nxdomain)
covers = dns_rdatatype_any;
else
covers = fctx->type;
/*
* Cache any negative cache entries in the message.
*/
result = ncache_message(fctx, covers, now);
}
done:
/*
* Remember the query's addrinfo, in case we need to mark the
* server as broken.
*/
addrinfo = query->addrinfo;
/*
* Cancel the query.
*
* XXXRTH Don't cancel the query if waiting for validation?
*/
fctx_cancelquery(&query, &devent, finish, ISC_FALSE);
if (keep_trying) {
if (result == DNS_R_FORMERR)
broken_server = ISC_TRUE;
if (broken_server) {
/*
* Add this server to the list of bad servers for
* this fctx.
*/
add_bad(fctx, &addrinfo->sockaddr);
}
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) {
FCTXTRACE("couldn't find a zonecut");
fctx_done(fctx, DNS_R_SERVFAIL);
return;
}
if (!dns_name_issubdomain(fname, &fctx->domain)) {
/*
* The best nameservers are now above our
* QDOMAIN.
*/
FCTXTRACE("nameservers now above QDOMAIN");
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_cancelqueries(fctx, ISC_TRUE);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
}
/*
* Try again.
*/
fctx_try(fctx);
} else if (resend) {
/*
* Resend (probably with changed options).
*/
FCTXTRACE("resend");
result = fctx_query(fctx, addrinfo, options);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result);
} 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.
*/
FCTXTRACE("wait for validator");
fctx_cancelqueries(fctx, ISC_TRUE);
/*
* We must not retransmit while the validator is working;
* it has references to the current rmessage.
*/
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);
REQUIRE(!res->priming);
REQUIRE(res->primefetch == NULL);
RTRACE("destroy");
DESTROYLOCK(&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);
DESTROYLOCK(&res->buckets[i].lock);
}
isc_mem_put(res->mctx, res->buckets,
res->nbuckets * sizeof (fctxbucket_t));
if (res->dispatchv4 != NULL)
dns_dispatch_detach(&res->dispatchv4);
if (res->dispatchv6 != NULL)
dns_dispatch_detach(&res->dispatchv6);
res->magic = 0;
isc_mem_put(res->mctx, res, sizeof *res);
}
static void
send_shutdown_events(dns_resolver_t *res) {
isc_event_t *event, *next_event;
isc_task_t *etask;
/*
* Caller must be holding the resolver lock.
*/
for (event = ISC_LIST_HEAD(res->whenshutdown);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, ev_link);
ISC_LIST_UNLINK(res->whenshutdown, event, ev_link);
etask = event->ev_sender;
event->ev_sender = res;
isc_task_sendanddetach(&etask, &event);
}
}
static void
empty_bucket(dns_resolver_t *res) {
RTRACE("empty_bucket");
LOCK(&res->lock);
INSIST(res->activebuckets > 0);
res->activebuckets--;
if (res->activebuckets == 0)
send_shutdown_events(res);
UNLOCK(&res->lock);
}
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,
unsigned int options,
dns_dispatchmgr_t *dispatchmgr,
dns_dispatch_t *dispatchv4,
dns_dispatch_t *dispatchv6,
dns_resolver_t **resp)
{
dns_resolver_t *res;
isc_result_t result = ISC_R_SUCCESS;
unsigned int i, buckets_created = 0;
char name[16];
/*
* Create a resolver.
*/
REQUIRE(DNS_VIEW_VALID(view));
REQUIRE(ntasks > 0);
REQUIRE(resp != NULL && *resp == NULL);
REQUIRE(dispatchmgr != NULL);
REQUIRE(dispatchv4 != NULL || dispatchv6 != NULL);
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->taskmgr = taskmgr;
res->dispatchmgr = dispatchmgr;
res->view = view;
res->options = options;
res->lame_ttl = 0;
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, 0, &res->buckets[i].task);
if (result != ISC_R_SUCCESS) {
DESTROYLOCK(&res->buckets[i].lock);
goto cleanup_buckets;
}
sprintf(name, "res%u", i);
isc_task_setname(res->buckets[i].task, name, res);
ISC_LIST_INIT(res->buckets[i].fctxs);
res->buckets[i].exiting = ISC_FALSE;
buckets_created++;
}
res->dispatchv4 = NULL;
if (dispatchv4 != NULL)
dns_dispatch_attach(dispatchv4, &res->dispatchv4);
res->dispatchv6 = NULL;
if (dispatchv6 != NULL)
dns_dispatch_attach(dispatchv6, &res->dispatchv6);
res->references = 1;
res->exiting = ISC_FALSE;
res->frozen = ISC_FALSE;
ISC_LIST_INIT(res->whenshutdown);
res->priming = ISC_FALSE;
res->primefetch = NULL;
result = isc_mutex_init(&res->lock);
if (result != ISC_R_SUCCESS)
goto cleanup_dispatches;
res->magic = RES_MAGIC;
*resp = res;
return (ISC_R_SUCCESS);
cleanup_dispatches:
if (res->dispatchv6 != NULL)
dns_dispatch_detach(&res->dispatchv6);
if (res->dispatchv4 != NULL)
dns_dispatch_detach(&res->dispatchv4);
cleanup_buckets:
for (i = 0; i < buckets_created; i++) {
DESTROYLOCK(&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);
}
static void
prime_done(isc_task_t *task, isc_event_t *event) {
dns_resolver_t *res;
dns_fetchevent_t *fevent;
dns_fetch_t *fetch;
REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
fevent = (dns_fetchevent_t *)event;
res = event->ev_arg;
REQUIRE(VALID_RESOLVER(res));
UNUSED(task);
LOCK(&res->lock);
INSIST(res->priming);
res->priming = ISC_FALSE;
fetch = res->primefetch;
res->primefetch = NULL;
UNLOCK(&res->lock);
if (fevent->node != NULL)
dns_db_detachnode(fevent->db, &fevent->node);
if (fevent->db != NULL)
dns_db_detach(&fevent->db);
if (dns_rdataset_isassociated(fevent->rdataset))
dns_rdataset_disassociate(fevent->rdataset);
INSIST(fevent->sigrdataset == NULL);
isc_mem_put(res->mctx, fevent->rdataset, sizeof *fevent->rdataset);
isc_event_free(&event);
dns_resolver_destroyfetch(&fetch);
}
void
dns_resolver_prime(dns_resolver_t *res) {
isc_boolean_t want_priming = ISC_FALSE;
dns_fetch_t *fetch;
dns_rdataset_t *rdataset;
isc_result_t result;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
RTRACE("dns_resolver_prime");
LOCK(&res->lock);
if (!res->exiting && !res->priming) {
INSIST(res->primefetch == NULL);
res->priming = ISC_TRUE;
want_priming = ISC_TRUE;
}
UNLOCK(&res->lock);
if (want_priming) {
/*
* To avoid any possible recursive locking problems, we
* start the priming fetch like any other fetch, and holding
* no resolver locks. No one else will try to start it
* because we're the ones who set res->priming to true.
* Any other callers of dns_resolver_prime() while we're
* running will see that res->priming is already true and
* do nothing.
*/
RTRACE("priming");
rdataset = isc_mem_get(res->mctx, sizeof *rdataset);
if (rdataset == NULL) {
LOCK(&res->lock);
INSIST(res->priming);
INSIST(res->primefetch == NULL);
res->priming = ISC_FALSE;
UNLOCK(&res->lock);
return;
}
dns_rdataset_init(rdataset);
fetch = NULL;
result = dns_resolver_createfetch(res, dns_rootname,
dns_rdatatype_ns,
NULL, NULL, NULL, 0,
res->buckets[0].task,
prime_done,
res, rdataset, NULL, &fetch);
LOCK(&res->lock);
INSIST(res->priming);
INSIST(res->primefetch == NULL);
if (result == ISC_R_SUCCESS)
res->primefetch = fetch;
else
res->priming = ISC_FALSE;
UNLOCK(&res->lock);
}
}
void
dns_resolver_freeze(dns_resolver_t *res) {
/*
* Freeze resolver.
*/
REQUIRE(VALID_RESOLVER(res));
REQUIRE(!res->frozen);
res->frozen = ISC_TRUE;
}
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_whenshutdown(dns_resolver_t *res, isc_task_t *task,
isc_event_t **eventp)
{
isc_task_t *clone;
isc_event_t *event;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(eventp != NULL);
event = *eventp;
*eventp = NULL;
LOCK(&res->lock);
if (res->exiting && res->activebuckets == 0) {
/*
* We're already shutdown. Send the event.
*/
event->ev_sender = res;
isc_task_send(task, &event);
} else {
clone = NULL;
isc_task_attach(task, &clone);
event->ev_sender = clone;
ISC_LIST_APPEND(res->whenshutdown, event, ev_link);
}
UNLOCK(&res->lock);
}
void
dns_resolver_shutdown(dns_resolver_t *res) {
unsigned int i;
fetchctx_t *fctx;
isc_socket_t *sock;
REQUIRE(VALID_RESOLVER(res));
RTRACE("shutdown");
LOCK(&res->lock);
if (!res->exiting) {
RTRACE("exiting");
res->exiting = ISC_TRUE;
for (i = 0; i < res->nbuckets; i++) {
LOCK(&res->buckets[i].lock);
for (fctx = ISC_LIST_HEAD(res->buckets[i].fctxs);
fctx != NULL;
fctx = ISC_LIST_NEXT(fctx, link))
fctx_shutdown(fctx);
if (res->dispatchv4 != NULL) {
sock = dns_dispatch_getsocket(res->dispatchv4);
isc_socket_cancel(sock, res->buckets[i].task,
ISC_SOCKCANCEL_ALL);
}
if (res->dispatchv6 != NULL) {
sock = dns_dispatch_getsocket(res->dispatchv6);
isc_socket_cancel(sock, 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)
send_shutdown_events(res);
}
UNLOCK(&res->lock);
}
void
dns_resolver_detach(dns_resolver_t **resp) {
dns_resolver_t *res;
isc_boolean_t need_destroy = ISC_FALSE;
REQUIRE(resp != NULL);
res = *resp;
REQUIRE(VALID_RESOLVER(res));
RTRACE("detach");
LOCK(&res->lock);
INSIST(res->references > 0);
res->references--;
if (res->references == 0) {
INSIST(res->exiting && 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));
}
static inline void
log_fetch(dns_name_t *name, dns_rdatatype_t type) {
char namebuf[DNS_NAME_FORMATSIZE];
char typebuf[DNS_RDATATYPE_FORMATSIZE];
int level = ISC_LOG_DEBUG(1);
if (! isc_log_wouldlog(dns_lctx, level))
return;
dns_name_format(name, namebuf, sizeof(namebuf));
dns_rdatatype_format(type, typebuf, sizeof(typebuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, level,
"createfetch: %s %s", namebuf, typebuf);
}
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;
UNUSED(forwarders);
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
/* XXXRTH Check for meta type */
if (domain != NULL) {
REQUIRE(DNS_RDATASET_VALID(nameservers));
REQUIRE(nameservers->type == dns_rdatatype_ns);
} else
REQUIRE(nameservers == NULL);
REQUIRE(forwarders == NULL);
REQUIRE(!dns_rdataset_isassociated(rdataset));
REQUIRE(sigrdataset == NULL ||
!dns_rdataset_isassociated(sigrdataset));
REQUIRE(fetchp != NULL && *fetchp == NULL);
log_fetch(name, type);
/*
* 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 we didn't have a fetch, would attach to a done fetch, this
* fetch has already cloned its results, or if the fetch has gone
* "idle" (no one was interested in it), we need to start a new
* fetch instead of joining with the existing one.
*/
if (fctx == NULL ||
fctx->state == fetchstate_done ||
fctx->cloned ||
ISC_LIST_EMPTY(fctx->events)) {
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, NULL,
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_fetch_t *fetch) {
fetchctx_t *fctx;
dns_resolver_t *res;
dns_fetchevent_t *event, *next_event;
isc_task_t *etask;
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
FTRACE("cancelfetch");
LOCK(&res->buckets[fctx->bucketnum].lock);
/*
* Find the completion event for this fetch (as opposed
* to those for other fetches that have joined the same
* fctx) and send it with result = ISC_R_CANCELED.
*/
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, ev_link);
if (event->fetch == fetch) {
ISC_LIST_UNLINK(fctx->events, event, ev_link);
break;
}
}
}
if (event != NULL) {
etask = event->ev_sender;
event->ev_sender = fctx;
event->result = ISC_R_CANCELED;
isc_task_sendanddetach(&etask, (isc_event_t **)&event);
}
/*
* The fctx continues running even if no fetches remain;
* the answer is still cached.
*/
UNLOCK(&res->buckets[fctx->bucketnum].lock);
}
void
dns_resolver_destroyfetch(dns_fetch_t **fetchp) {
dns_fetch_t *fetch;
dns_resolver_t *res;
dns_fetchevent_t *event, *next_event;
fetchctx_t *fctx;
unsigned int bucketnum;
isc_boolean_t bucket_empty = ISC_FALSE;
REQUIRE(fetchp != NULL);
fetch = *fetchp;
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
FTRACE("destroyfetch");
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
/*
* Sanity check: the caller should have gotten its event 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, ev_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.
*/
if (fctx->pending == 0 && ISC_LIST_EMPTY(fctx->validators) &&
SHUTTINGDOWN(fctx)) {
/*
* This fctx is already shutdown; we were just
* waiting for the last reference to go away.
*/
bucket_empty = fctx_destroy(fctx);
} else {
/*
* Initiate shutdown.
*/
fctx_shutdown(fctx);
}
}
UNLOCK(&res->buckets[bucketnum].lock);
isc_mem_put(res->mctx, fetch, sizeof *fetch);
*fetchp = NULL;
if (bucket_empty)
empty_bucket(res);
}
dns_dispatchmgr_t *
dns_resolver_dispatchmgr(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->dispatchmgr);
}
dns_dispatch_t *
dns_resolver_dispatchv4(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->dispatchv4);
}
dns_dispatch_t *
dns_resolver_dispatchv6(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->dispatchv6);
}
isc_socketmgr_t *
dns_resolver_socketmgr(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->socketmgr);
}
isc_taskmgr_t *
dns_resolver_taskmgr(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->taskmgr);
}
isc_uint32_t
dns_resolver_getlamettl(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->lame_ttl);
}
void
dns_resolver_setlamettl(dns_resolver_t *resolver, isc_uint32_t lame_ttl) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->lame_ttl = lame_ttl;
}