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Diffstat (limited to '')
| -rw-r--r-- | lib/dns/byaddr.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/lib/dns/byaddr.c b/lib/dns/byaddr.c new file mode 100644 index 0000000..8fa668a --- /dev/null +++ b/lib/dns/byaddr.c @@ -0,0 +1,282 @@ +/* + * 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 <stdbool.h> + +#include <isc/mem.h> +#include <isc/netaddr.h> +#include <isc/print.h> +#include <isc/result.h> +#include <isc/string.h> /* Required for HP/UX (and others?) */ +#include <isc/task.h> +#include <isc/util.h> + +#include <dns/byaddr.h> +#include <dns/db.h> +#include <dns/events.h> +#include <dns/lookup.h> +#include <dns/rdata.h> +#include <dns/rdataset.h> +#include <dns/rdatastruct.h> +#include <dns/resolver.h> +#include <dns/view.h> + +/* + * 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 **)&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)); +} |