/* $NetBSD: lookup.c,v 1.7.2.1 2024/02/25 15:46:50 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ /*! \file */ #include #include #include #include #include /* Required for HP/UX (and others?) */ #include #include #include #include #include #include #include #include #include #include struct dns_lookup { /* Unlocked. */ unsigned int magic; isc_mem_t *mctx; isc_mutex_t lock; dns_rdatatype_t type; dns_fixedname_t name; /* Locked by lock. */ unsigned int options; isc_task_t *task; dns_view_t *view; dns_lookupevent_t *event; dns_fetch_t *fetch; unsigned int restarts; bool canceled; dns_rdataset_t rdataset; dns_rdataset_t sigrdataset; }; #define LOOKUP_MAGIC ISC_MAGIC('l', 'o', 'o', 'k') #define VALID_LOOKUP(l) ISC_MAGIC_VALID((l), LOOKUP_MAGIC) #define MAX_RESTARTS 16 static void lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event); static void fetch_done(isc_task_t *task, isc_event_t *event) { dns_lookup_t *lookup = event->ev_arg; dns_fetchevent_t *fevent; UNUSED(task); REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE); REQUIRE(VALID_LOOKUP(lookup)); REQUIRE(lookup->task == task); fevent = (dns_fetchevent_t *)event; REQUIRE(fevent->fetch == lookup->fetch); lookup_find(lookup, fevent); } static isc_result_t start_fetch(dns_lookup_t *lookup) { isc_result_t result; /* * The caller must be holding the lookup's lock. */ REQUIRE(lookup->fetch == NULL); result = dns_resolver_createfetch( lookup->view->resolver, dns_fixedname_name(&lookup->name), lookup->type, NULL, NULL, NULL, NULL, 0, 0, 0, NULL, lookup->task, fetch_done, lookup, &lookup->rdataset, &lookup->sigrdataset, &lookup->fetch); return (result); } static void build_event(dns_lookup_t *lookup) { dns_name_t *name = NULL; dns_rdataset_t *rdataset = NULL; dns_rdataset_t *sigrdataset = NULL; name = isc_mem_get(lookup->mctx, sizeof(dns_name_t)); dns_name_init(name, NULL); dns_name_dup(dns_fixedname_name(&lookup->name), lookup->mctx, name); if (dns_rdataset_isassociated(&lookup->rdataset)) { rdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t)); dns_rdataset_init(rdataset); dns_rdataset_clone(&lookup->rdataset, rdataset); } if (dns_rdataset_isassociated(&lookup->sigrdataset)) { sigrdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t)); dns_rdataset_init(sigrdataset); dns_rdataset_clone(&lookup->sigrdataset, sigrdataset); } lookup->event->name = name; lookup->event->rdataset = rdataset; lookup->event->sigrdataset = sigrdataset; } static isc_result_t view_find(dns_lookup_t *lookup, dns_name_t *foundname) { isc_result_t result; dns_name_t *name = dns_fixedname_name(&lookup->name); dns_rdatatype_t type; if (lookup->type == dns_rdatatype_rrsig) { type = dns_rdatatype_any; } else { type = lookup->type; } result = dns_view_find(lookup->view, name, type, 0, 0, false, false, &lookup->event->db, &lookup->event->node, foundname, &lookup->rdataset, &lookup->sigrdataset); return (result); } static void lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event) { isc_result_t result = ISC_R_SUCCESS; bool want_restart; bool send_event; dns_name_t *name = NULL, *fname = NULL, *prefix = NULL; dns_fixedname_t foundname, fixed; dns_rdata_t rdata = DNS_RDATA_INIT; unsigned int nlabels; int order; dns_namereln_t namereln; dns_rdata_cname_t cname; dns_rdata_dname_t dname; REQUIRE(VALID_LOOKUP(lookup)); LOCK(&lookup->lock); name = dns_fixedname_name(&lookup->name); do { lookup->restarts++; want_restart = false; send_event = true; if (event == NULL && !lookup->canceled) { fname = dns_fixedname_initname(&foundname); INSIST(!dns_rdataset_isassociated(&lookup->rdataset)); INSIST(!dns_rdataset_isassociated( &lookup->sigrdataset)); /* * If we have restarted then clear the old node. */ if (lookup->event->node != NULL) { INSIST(lookup->event->db != NULL); dns_db_detachnode(lookup->event->db, &lookup->event->node); } if (lookup->event->db != NULL) { dns_db_detach(&lookup->event->db); } result = view_find(lookup, fname); if (result == ISC_R_NOTFOUND) { /* * We don't know anything about the name. * Launch a fetch. */ if (lookup->event->node != NULL) { INSIST(lookup->event->db != NULL); dns_db_detachnode(lookup->event->db, &lookup->event->node); } if (lookup->event->db != NULL) { dns_db_detach(&lookup->event->db); } result = start_fetch(lookup); if (result == ISC_R_SUCCESS) { send_event = false; } goto done; } } else if (event != NULL) { result = event->result; fname = event->foundname; dns_resolver_destroyfetch(&lookup->fetch); INSIST(event->rdataset == &lookup->rdataset); INSIST(event->sigrdataset == &lookup->sigrdataset); } /* * If we've been canceled, forget about the result. */ if (lookup->canceled) { result = ISC_R_CANCELED; } switch (result) { case ISC_R_SUCCESS: build_event(lookup); if (event == NULL) { break; } if (event->db != NULL) { dns_db_attach(event->db, &lookup->event->db); } if (event->node != NULL) { dns_db_attachnode(lookup->event->db, event->node, &lookup->event->node); } break; case DNS_R_CNAME: /* * Copy the CNAME's target into the lookup's * query name and start over. */ result = dns_rdataset_first(&lookup->rdataset); if (result != ISC_R_SUCCESS) { break; } dns_rdataset_current(&lookup->rdataset, &rdata); result = dns_rdata_tostruct(&rdata, &cname, NULL); dns_rdata_reset(&rdata); if (result != ISC_R_SUCCESS) { break; } dns_name_copy(&cname.cname, name); dns_rdata_freestruct(&cname); want_restart = true; send_event = false; break; case DNS_R_DNAME: namereln = dns_name_fullcompare(name, fname, &order, &nlabels); INSIST(namereln == dns_namereln_subdomain); /* * Get the target name of the DNAME. */ result = dns_rdataset_first(&lookup->rdataset); if (result != ISC_R_SUCCESS) { break; } dns_rdataset_current(&lookup->rdataset, &rdata); result = dns_rdata_tostruct(&rdata, &dname, NULL); dns_rdata_reset(&rdata); if (result != ISC_R_SUCCESS) { break; } /* * Construct the new query name and start over. */ prefix = dns_fixedname_initname(&fixed); dns_name_split(name, nlabels, prefix, NULL); result = dns_name_concatenate(prefix, &dname.dname, name, NULL); dns_rdata_freestruct(&dname); if (result == ISC_R_SUCCESS) { want_restart = true; send_event = false; } break; default: send_event = true; } if (dns_rdataset_isassociated(&lookup->rdataset)) { dns_rdataset_disassociate(&lookup->rdataset); } if (dns_rdataset_isassociated(&lookup->sigrdataset)) { dns_rdataset_disassociate(&lookup->sigrdataset); } done: if (event != NULL) { if (event->node != NULL) { dns_db_detachnode(event->db, &event->node); } if (event->db != NULL) { dns_db_detach(&event->db); } isc_event_free(ISC_EVENT_PTR(&event)); } /* * Limit the number of restarts. */ if (want_restart && lookup->restarts == MAX_RESTARTS) { want_restart = false; result = ISC_R_QUOTA; send_event = true; } } while (want_restart); if (send_event) { lookup->event->result = result; lookup->event->ev_sender = lookup; isc_task_sendanddetach(&lookup->task, (isc_event_t **)(void *)&lookup->event); dns_view_detach(&lookup->view); } UNLOCK(&lookup->lock); } static void levent_destroy(isc_event_t *event) { dns_lookupevent_t *levent; isc_mem_t *mctx; REQUIRE(event->ev_type == DNS_EVENT_LOOKUPDONE); mctx = event->ev_destroy_arg; levent = (dns_lookupevent_t *)event; if (levent->name != NULL) { if (dns_name_dynamic(levent->name)) { dns_name_free(levent->name, mctx); } isc_mem_put(mctx, levent->name, sizeof(dns_name_t)); } if (levent->rdataset != NULL) { dns_rdataset_disassociate(levent->rdataset); isc_mem_put(mctx, levent->rdataset, sizeof(dns_rdataset_t)); } if (levent->sigrdataset != NULL) { dns_rdataset_disassociate(levent->sigrdataset); isc_mem_put(mctx, levent->sigrdataset, sizeof(dns_rdataset_t)); } if (levent->node != NULL) { dns_db_detachnode(levent->db, &levent->node); } if (levent->db != NULL) { dns_db_detach(&levent->db); } isc_mem_put(mctx, event, event->ev_size); } isc_result_t dns_lookup_create(isc_mem_t *mctx, const dns_name_t *name, dns_rdatatype_t type, dns_view_t *view, unsigned int options, isc_task_t *task, isc_taskaction_t action, void *arg, dns_lookup_t **lookupp) { dns_lookup_t *lookup; isc_event_t *ievent; lookup = isc_mem_get(mctx, sizeof(*lookup)); lookup->mctx = NULL; isc_mem_attach(mctx, &lookup->mctx); lookup->options = options; ievent = isc_event_allocate(mctx, lookup, DNS_EVENT_LOOKUPDONE, action, arg, sizeof(*lookup->event)); lookup->event = (dns_lookupevent_t *)ievent; lookup->event->ev_destroy = levent_destroy; lookup->event->ev_destroy_arg = mctx; lookup->event->result = ISC_R_FAILURE; lookup->event->name = NULL; lookup->event->rdataset = NULL; lookup->event->sigrdataset = NULL; lookup->event->db = NULL; lookup->event->node = NULL; lookup->task = NULL; isc_task_attach(task, &lookup->task); isc_mutex_init(&lookup->lock); dns_fixedname_init(&lookup->name); dns_name_copy(name, dns_fixedname_name(&lookup->name)); lookup->type = type; lookup->view = NULL; dns_view_attach(view, &lookup->view); lookup->fetch = NULL; lookup->restarts = 0; lookup->canceled = false; dns_rdataset_init(&lookup->rdataset); dns_rdataset_init(&lookup->sigrdataset); lookup->magic = LOOKUP_MAGIC; *lookupp = lookup; lookup_find(lookup, NULL); return (ISC_R_SUCCESS); } void dns_lookup_cancel(dns_lookup_t *lookup) { REQUIRE(VALID_LOOKUP(lookup)); LOCK(&lookup->lock); if (!lookup->canceled) { lookup->canceled = true; if (lookup->fetch != NULL) { INSIST(lookup->view != NULL); dns_resolver_cancelfetch(lookup->fetch); } } UNLOCK(&lookup->lock); } void dns_lookup_destroy(dns_lookup_t **lookupp) { dns_lookup_t *lookup; REQUIRE(lookupp != NULL); lookup = *lookupp; *lookupp = NULL; REQUIRE(VALID_LOOKUP(lookup)); REQUIRE(lookup->event == NULL); REQUIRE(lookup->task == NULL); REQUIRE(lookup->view == NULL); if (dns_rdataset_isassociated(&lookup->rdataset)) { dns_rdataset_disassociate(&lookup->rdataset); } if (dns_rdataset_isassociated(&lookup->sigrdataset)) { dns_rdataset_disassociate(&lookup->sigrdataset); } isc_mutex_destroy(&lookup->lock); lookup->magic = 0; isc_mem_putanddetach(&lookup->mctx, lookup, sizeof(*lookup)); }