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support freezing; basic forwarding

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This commit is contained in:
Bob Halley
2000-01-12 02:59:48 +00:00
parent 4226a822e8
commit 7c2fd18a36
2 changed files with 277 additions and 23 deletions
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66
lib/dns/include/dns/resolver.h
View File

@@ -128,6 +128,60 @@ dns_resolver_create(dns_view_t *view,
* Anything else Failure.
*/
isc_result_t
dns_resolver_setforwarders(dns_resolver_t *res,
isc_sockaddrlist_t *forwarders);
/*
* Set the default forwarders to be used by the resolver.
*
* Requires:
*
* 'res' is a valid, unfrozen resolver.
*
* 'forwarders' is a valid nonempty list.
*
* Returns:
*
* ISC_R_SUCCESS
* ISC_R_NOMEMORY
*/
isc_result_t
dns_resolver_setfwdpolicy(dns_resolver_t *res, dns_fwdpolicy_t fwdpolicy);
/*
* Set the default forwarding policy to be used by the resolver.
*
* Requires:
*
* 'res' is a valid, unfrozen resolver.
*
* 'fwdpolicy' is a valid dns_fwdpolicy_t.
*
* Returns:
*
* ISC_R_SUCCESS
*/
void
dns_resolver_freeze(dns_resolver_t *res);
/*
* Freeze resolver.
*
* Notes:
*
* Certain configuration changes, e.g. setting forwarders,
* cannot be made after the resolver is frozen. Fetches
* cannot be created until the resolver is frozen.
*
* Requires:
*
* 'res' is a valid, unfrozen resolver.
*
* Ensures:
*
* 'res' is frozen.
*/
void
dns_resolver_whenshutdown(dns_resolver_t *res, isc_task_t *task,
isc_event_t **eventp);
@@ -204,7 +258,7 @@ dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
*
* Requires:
*
* 'res' is a valid resolver.
* 'res' is a valid resolver that has been frozen.
*
* 'name' is a valid name.
*
@@ -241,6 +295,12 @@ dns_resolver_cancelfetch(dns_resolver_t *res, dns_fetch_t *fetch);
*
* If 'fetch' has not completed, post its FETCHDONE event with a
* result code of ISC_R_CANCELED.
*
* Requires:
*
* 'res' is a valid resolver that has been frozen.
*
* 'fetch' is a valid fetch.
*/
void
@@ -250,6 +310,10 @@ dns_resolver_destroyfetch(dns_resolver_t *res, dns_fetch_t **fetchp);
*
* Requires:
*
* 'res' is a valid resolver that has been frozen.
*
* '*fetchp' is a valid fetch.
*
* The caller has received the FETCHDONE event (either because the
* fetch completed or because dns_resolver_cancelfetch() was called).
*

234
lib/dns/resolver.c
View File

@@ -154,6 +154,8 @@ struct fetchctx {
ISC_LIST(resquery_t) queries;
dns_adbfindlist_t finds;
dns_adbfind_t * find;
dns_adbaddrinfolist_t forwaddrs;
isc_sockaddrlist_t forwarders;
/*
* # of events we're waiting for.
*/
@@ -209,23 +211,36 @@ struct dns_resolver {
isc_socketmgr_t * socketmgr;
isc_timermgr_t * timermgr;
dns_view_t * view;
/* Locked by lock. */
unsigned int references;
isc_boolean_t exiting;
isc_eventlist_t whenshutdown;
isc_boolean_t frozen;
isc_sockaddrlist_t forwarders;
dns_fwdpolicy_t fwdpolicy;
isc_socket_t * udpsocket4;
isc_socket_t * udpsocket6;
dns_dispatch_t * dispatch4;
dns_dispatch_t * dispatch6;
unsigned int nbuckets;
unsigned int activebuckets;
fctxbucket_t * buckets;
/* Locked by lock. */
unsigned int references;
isc_boolean_t exiting;
isc_eventlist_t whenshutdown;
unsigned int activebuckets;
};
#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);
@@ -384,11 +399,27 @@ fctx_cleanupfinds(fetchctx_t *fctx) {
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) {
FCTXTRACE("stopeverything");
fctx_cancelqueries(fctx, ISC_FALSE);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
fctx_stoptimer(fctx);
}
@@ -736,8 +767,15 @@ resquery_send(resquery_t *query) {
dns_rdataset_makequestion(qrdataset, res->rdclass, fctx->type);
ISC_LIST_APPEND(qname->list, qrdataset, link);
dns_message_addname(fctx->qmessage, qname, DNS_SECTION_QUESTION);
if ((query->options & DNS_FETCHOPT_RECURSIVE) != 0)
/*
* 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.
*/
@@ -1015,6 +1053,8 @@ fctx_getaddresses(fetchctx_t *fctx) {
isc_stdtime_t now;
dns_adbfind_t *find;
unsigned int stdoptions, options;
isc_sockaddr_t *sa;
dns_adbaddrinfo_t *ai;
FCTXTRACE("getaddresses");
@@ -1026,6 +1066,43 @@ fctx_getaddresses(fetchctx_t *fctx) {
return (DNS_R_SERVFAIL);
res = fctx->res;
/*
* Forwarders.
*/
INSIST(ISC_LIST_EMPTY(fctx->forwaddrs));
/*
* If this fctx has forwarders, use them; otherwise the use
* resolver's forwarders (if any).
*/
sa = ISC_LIST_HEAD(fctx->forwarders);
if (sa == NULL)
sa = ISC_LIST_HEAD(res->forwarders);
while (sa != NULL) {
ai = NULL;
result = dns_adb_findaddrinfo(fctx->res->view->adb,
sa, &ai);
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 (res->fwdpolicy == dns_fwdpolicy_only)
goto out;
/*
* Normal nameservers.
*/
stdoptions = DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT |
DNS_ADBFIND_AVOIDFETCHES;
if (res->dispatch4 != NULL)
@@ -1105,23 +1182,35 @@ fctx_getaddresses(fetchctx_t *fctx) {
if (result != DNS_R_NOMORE)
return (result);
if (ISC_LIST_EMPTY(fctx->finds) && fctx->pending > 0) {
out:
if (ISC_LIST_EMPTY(fctx->finds) && ISC_LIST_EMPTY(fctx->forwaddrs)) {
/*
* We're fetching the addresses, but don't have any yet.
* Tell the caller to wait for an answer.
* We've got no addresses.
*/
result = DNS_R_WAIT;
} else if (ISC_LIST_EMPTY(fctx->finds)) {
/*
* We've lost completely. We don't know any addresses, and
* the ADB has told us it can't get them.
*/
result = ISC_R_FAILURE;
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 {
/*
* We've lost completely. We don't know any
* addresses, and the ADB has told us it can't get
* them.
*/
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;
}
@@ -1129,10 +1218,6 @@ fctx_getaddresses(fetchctx_t *fctx) {
return (result);
}
#define FCTX_ADDRINFO_MARK 0x01
#define UNMARKED(a) (((a)->flags & FCTX_ADDRINFO_MARK) \
== 0)
static inline dns_adbaddrinfo_t *
fctx_nextaddress(fetchctx_t *fctx) {
dns_adbfind_t *find;
@@ -1143,7 +1228,20 @@ fctx_nextaddress(fetchctx_t *fctx) {
*/
/*
* Move to the next find.
* Find the first unmarked forwarder (if any).
*/
for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
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)
@@ -1199,6 +1297,7 @@ fctx_try(fetchctx_t *fctx) {
*/
fctx_cancelqueries(fctx, ISC_TRUE);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
result = fctx_getaddresses(fctx);
if (result == DNS_R_WAIT) {
/*
@@ -1519,6 +1618,8 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
fctx->want_shutdown = ISC_FALSE;
ISC_LIST_INIT(fctx->queries);
ISC_LIST_INIT(fctx->finds);
ISC_LIST_INIT(fctx->forwaddrs);
ISC_LIST_INIT(fctx->forwarders);
fctx->find = NULL;
fctx->pending = 0;
fctx->validating = 0;
@@ -3111,6 +3212,7 @@ resquery_response(isc_task_t *task, isc_event_t *event) {
}
fctx_cancelqueries(fctx, ISC_TRUE);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
}
/*
* Try again.
@@ -3146,6 +3248,19 @@ resquery_response(isc_task_t *task, isc_event_t *event) {
*** Resolver Methods
***/
static void
free_forwarders(dns_resolver_t *res) {
isc_sockaddr_t *sa, *next_sa;
for (sa = ISC_LIST_HEAD(res->forwarders);
sa != NULL;
sa = next_sa) {
next_sa = ISC_LIST_NEXT(sa, link);
ISC_LIST_UNLINK(res->forwarders, sa, link);
isc_mem_put(res->mctx, sa, sizeof *sa);
}
}
static void
destroy(dns_resolver_t *res) {
unsigned int i;
@@ -3171,6 +3286,7 @@ destroy(dns_resolver_t *res) {
dns_dispatch_detach(&res->dispatch6);
if (res->udpsocket6 != NULL)
isc_socket_detach(&res->udpsocket6);
free_forwarders(res);
res->magic = 0;
isc_mem_put(res->mctx, res, sizeof *res);
}
@@ -3323,9 +3439,16 @@ dns_resolver_create(dns_view_t *view,
if (result != ISC_R_SUCCESS)
goto cleanup_udpsocket6;
}
/*
* Forwarding.
*/
ISC_LIST_INIT(res->forwarders);
res->fwdpolicy = dns_fwdpolicy_none;
res->references = 1;
res->exiting = ISC_FALSE;
res->frozen = ISC_FALSE;
ISC_LIST_INIT(res->whenshutdown);
result = isc_mutex_init(&res->lock);
@@ -3369,6 +3492,68 @@ dns_resolver_create(dns_view_t *view,
return (result);
}
isc_result_t
dns_resolver_setforwarders(dns_resolver_t *res,
isc_sockaddrlist_t *forwarders)
{
isc_sockaddr_t *sa, *nsa;
/*
* Set the default forwarders to be used by the resolver.
*/
REQUIRE(VALID_RESOLVER(res));
REQUIRE(!res->frozen);
REQUIRE(!ISC_LIST_EMPTY(*forwarders));
if (!ISC_LIST_EMPTY(res->forwarders))
free_forwarders(res);
for (sa = ISC_LIST_HEAD(*forwarders);
sa != NULL;
sa = ISC_LIST_NEXT(sa, link)) {
nsa = isc_mem_get(res->mctx, sizeof *nsa);
if (nsa == NULL) {
free_forwarders(res);
return (ISC_R_NOMEMORY);
}
/* XXXRTH Create and use isc_sockaddr_copy(). */
*nsa = *sa;
ISC_LINK_INIT(nsa, link);
ISC_LIST_APPEND(res->forwarders, nsa, link);
}
return (ISC_R_SUCCESS);
}
isc_result_t
dns_resolver_setfwdpolicy(dns_resolver_t *res, dns_fwdpolicy_t fwdpolicy) {
/*
* Set the default forwarding policy to be used by the resolver.
*/
REQUIRE(VALID_RESOLVER(res));
REQUIRE(!res->frozen);
res->fwdpolicy = fwdpolicy;
return (ISC_R_SUCCESS);
}
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));
@@ -3562,6 +3747,7 @@ dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
(void)forwarders;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
/* XXXRTH Check for meta type */
REQUIRE(DNS_RDATASET_VALID(nameservers));
REQUIRE(forwarders == NULL);
@@ -3646,6 +3832,8 @@ dns_resolver_cancelfetch(dns_resolver_t *res, dns_fetch_t *fetch) {
dns_fetchevent_t *event, *next_event;
isc_task_t *etask;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
@@ -3684,6 +3872,8 @@ dns_resolver_destroyfetch(dns_resolver_t *res, dns_fetch_t **fetchp) {
unsigned int bucketnum;
isc_boolean_t bucket_empty = ISC_FALSE;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
REQUIRE(fetchp != NULL);
fetch = *fetchp;
REQUIRE(DNS_FETCH_VALID(fetch));