/* $NetBSD: byaddr.c,v 1.7.2.2 2024/02/25 15:46:48 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 #include /* Required for HP/UX (and others?) */ #include #include #include #include #include #include #include #include #include #include #include /* * XXXRTH We could use a static event... */ static char hex_digits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; isc_result_t dns_byaddr_createptrname(const isc_netaddr_t *address, unsigned int options, dns_name_t *name) { char textname[128]; const unsigned char *bytes; int i; char *cp; isc_buffer_t buffer; unsigned int len; REQUIRE(address != NULL); UNUSED(options); /* * We create the text representation and then convert to a * dns_name_t. This is not maximally efficient, but it keeps all * of the knowledge of wire format in the dns_name_ routines. */ bytes = (const unsigned char *)(&address->type); if (address->family == AF_INET) { (void)snprintf(textname, sizeof(textname), "%u.%u.%u.%u.in-addr.arpa.", ((unsigned int)bytes[3] & 0xffU), ((unsigned int)bytes[2] & 0xffU), ((unsigned int)bytes[1] & 0xffU), ((unsigned int)bytes[0] & 0xffU)); } else if (address->family == AF_INET6) { size_t remaining; cp = textname; for (i = 15; i >= 0; i--) { *cp++ = hex_digits[bytes[i] & 0x0f]; *cp++ = '.'; *cp++ = hex_digits[(bytes[i] >> 4) & 0x0f]; *cp++ = '.'; } remaining = sizeof(textname) - (cp - textname); strlcpy(cp, "ip6.arpa.", remaining); } else { return (ISC_R_NOTIMPLEMENTED); } len = (unsigned int)strlen(textname); isc_buffer_init(&buffer, textname, len); isc_buffer_add(&buffer, len); return (dns_name_fromtext(name, &buffer, dns_rootname, 0, NULL)); } struct dns_byaddr { /* Unlocked. */ unsigned int magic; isc_mem_t *mctx; isc_mutex_t lock; dns_fixedname_t name; /* Locked by lock. */ unsigned int options; dns_lookup_t *lookup; isc_task_t *task; dns_byaddrevent_t *event; bool canceled; }; #define BYADDR_MAGIC ISC_MAGIC('B', 'y', 'A', 'd') #define VALID_BYADDR(b) ISC_MAGIC_VALID(b, BYADDR_MAGIC) #define MAX_RESTARTS 16 static isc_result_t copy_ptr_targets(dns_byaddr_t *byaddr, dns_rdataset_t *rdataset) { isc_result_t result; dns_name_t *name; dns_rdata_t rdata = DNS_RDATA_INIT; /* * The caller must be holding the byaddr's lock. */ result = dns_rdataset_first(rdataset); while (result == ISC_R_SUCCESS) { dns_rdata_ptr_t ptr; dns_rdataset_current(rdataset, &rdata); result = dns_rdata_tostruct(&rdata, &ptr, NULL); if (result != ISC_R_SUCCESS) { return (result); } name = isc_mem_get(byaddr->mctx, sizeof(*name)); dns_name_init(name, NULL); dns_name_dup(&ptr.ptr, byaddr->mctx, name); dns_rdata_freestruct(&ptr); ISC_LIST_APPEND(byaddr->event->names, name, link); dns_rdata_reset(&rdata); result = dns_rdataset_next(rdataset); } if (result == ISC_R_NOMORE) { result = ISC_R_SUCCESS; } return (result); } static void lookup_done(isc_task_t *task, isc_event_t *event) { dns_byaddr_t *byaddr = event->ev_arg; dns_lookupevent_t *levent; isc_result_t result; REQUIRE(event->ev_type == DNS_EVENT_LOOKUPDONE); REQUIRE(VALID_BYADDR(byaddr)); REQUIRE(byaddr->task == task); UNUSED(task); levent = (dns_lookupevent_t *)event; if (levent->result == ISC_R_SUCCESS) { result = copy_ptr_targets(byaddr, levent->rdataset); byaddr->event->result = result; } else { byaddr->event->result = levent->result; } isc_event_free(&event); isc_task_sendanddetach(&byaddr->task, (isc_event_t **)(void *)&byaddr->event); } static void bevent_destroy(isc_event_t *event) { dns_byaddrevent_t *bevent; dns_name_t *name, *next_name; isc_mem_t *mctx; REQUIRE(event->ev_type == DNS_EVENT_BYADDRDONE); mctx = event->ev_destroy_arg; bevent = (dns_byaddrevent_t *)event; for (name = ISC_LIST_HEAD(bevent->names); name != NULL; name = next_name) { next_name = ISC_LIST_NEXT(name, link); ISC_LIST_UNLINK(bevent->names, name, link); dns_name_free(name, mctx); isc_mem_put(mctx, name, sizeof(*name)); } isc_mem_put(mctx, event, event->ev_size); } isc_result_t dns_byaddr_create(isc_mem_t *mctx, const isc_netaddr_t *address, dns_view_t *view, unsigned int options, isc_task_t *task, isc_taskaction_t action, void *arg, dns_byaddr_t **byaddrp) { isc_result_t result; dns_byaddr_t *byaddr; isc_event_t *ievent; byaddr = isc_mem_get(mctx, sizeof(*byaddr)); byaddr->mctx = NULL; isc_mem_attach(mctx, &byaddr->mctx); byaddr->options = options; byaddr->event = isc_mem_get(mctx, sizeof(*byaddr->event)); ISC_EVENT_INIT(byaddr->event, sizeof(*byaddr->event), 0, NULL, DNS_EVENT_BYADDRDONE, action, arg, byaddr, bevent_destroy, mctx); byaddr->event->result = ISC_R_FAILURE; ISC_LIST_INIT(byaddr->event->names); byaddr->task = NULL; isc_task_attach(task, &byaddr->task); isc_mutex_init(&byaddr->lock); dns_fixedname_init(&byaddr->name); result = dns_byaddr_createptrname(address, options, dns_fixedname_name(&byaddr->name)); if (result != ISC_R_SUCCESS) { goto cleanup_lock; } byaddr->lookup = NULL; result = dns_lookup_create(mctx, dns_fixedname_name(&byaddr->name), dns_rdatatype_ptr, view, 0, task, lookup_done, byaddr, &byaddr->lookup); if (result != ISC_R_SUCCESS) { goto cleanup_lock; } byaddr->canceled = false; byaddr->magic = BYADDR_MAGIC; *byaddrp = byaddr; return (ISC_R_SUCCESS); cleanup_lock: isc_mutex_destroy(&byaddr->lock); ievent = (isc_event_t *)byaddr->event; isc_event_free(&ievent); byaddr->event = NULL; isc_task_detach(&byaddr->task); isc_mem_putanddetach(&mctx, byaddr, sizeof(*byaddr)); return (result); } void dns_byaddr_cancel(dns_byaddr_t *byaddr) { REQUIRE(VALID_BYADDR(byaddr)); LOCK(&byaddr->lock); if (!byaddr->canceled) { byaddr->canceled = true; if (byaddr->lookup != NULL) { dns_lookup_cancel(byaddr->lookup); } } UNLOCK(&byaddr->lock); } void dns_byaddr_destroy(dns_byaddr_t **byaddrp) { dns_byaddr_t *byaddr; REQUIRE(byaddrp != NULL); byaddr = *byaddrp; *byaddrp = NULL; REQUIRE(VALID_BYADDR(byaddr)); REQUIRE(byaddr->event == NULL); REQUIRE(byaddr->task == NULL); dns_lookup_destroy(&byaddr->lookup); isc_mutex_destroy(&byaddr->lock); byaddr->magic = 0; isc_mem_putanddetach(&byaddr->mctx, byaddr, sizeof(*byaddr)); }