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-rw-r--r--libcli/dns/dns.c591
1 files changed, 591 insertions, 0 deletions
diff --git a/libcli/dns/dns.c b/libcli/dns/dns.c
new file mode 100644
index 0000000..943b4d5
--- /dev/null
+++ b/libcli/dns/dns.c
@@ -0,0 +1,591 @@
+/*
+ Unix SMB/CIFS implementation.
+
+ Small async DNS library for Samba with socketwrapper support
+
+ Copyright (C) 2010 Kai Blin <kai@samba.org>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/network.h"
+#include <tevent.h>
+#include "lib/tsocket/tsocket.h"
+#include "libcli/dns/libdns.h"
+#include "lib/util/tevent_unix.h"
+#include "lib/util/samba_util.h"
+#include "lib/util/debug.h"
+#include "libcli/util/error.h"
+#include "librpc/ndr/libndr.h"
+#include "librpc/gen_ndr/ndr_dns.h"
+
+struct dns_udp_request_state {
+ struct tevent_context *ev;
+ struct tdgram_context *dgram;
+ size_t query_len;
+ uint8_t *reply;
+ size_t reply_len;
+};
+
+#define DNS_REQUEST_TIMEOUT 10
+
+/* Declare callback functions used below. */
+static void dns_udp_request_get_reply(struct tevent_req *subreq);
+static void dns_udp_request_done(struct tevent_req *subreq);
+
+static struct tevent_req *dns_udp_request_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ const char *server_addr_string,
+ const uint8_t *query,
+ size_t query_len)
+{
+ struct tevent_req *req, *subreq;
+ struct dns_udp_request_state *state;
+ struct tsocket_address *local_addr, *server_addr;
+ struct tdgram_context *dgram;
+ int ret;
+
+ req = tevent_req_create(mem_ctx, &state, struct dns_udp_request_state);
+ if (req == NULL) {
+ return NULL;
+ }
+
+ state->ev = ev;
+
+ /* Use connected UDP sockets */
+ ret = tsocket_address_inet_from_strings(state, "ip", NULL, 0,
+ &local_addr);
+ if (ret != 0) {
+ tevent_req_error(req, errno);
+ return tevent_req_post(req, ev);
+ }
+
+ ret = tsocket_address_inet_from_hostport_strings(
+ state, "ip", server_addr_string, DNS_SERVICE_PORT, &server_addr);
+ if (ret != 0) {
+ tevent_req_error(req, errno);
+ return tevent_req_post(req, ev);
+ }
+
+ ret = tdgram_inet_udp_socket(local_addr, server_addr, state, &dgram);
+ if (ret != 0) {
+ tevent_req_error(req, errno);
+ return tevent_req_post(req, ev);
+ }
+
+ state->dgram = dgram;
+ state->query_len = query_len;
+
+ dump_data(10, query, query_len);
+
+ subreq = tdgram_sendto_send(state, ev, dgram, query, query_len, NULL);
+ if (tevent_req_nomem(subreq, req)) {
+ return tevent_req_post(req, ev);
+ }
+
+ if (!tevent_req_set_endtime(req, ev,
+ timeval_current_ofs(DNS_REQUEST_TIMEOUT, 0))) {
+ return tevent_req_post(req, ev);
+ }
+
+ tevent_req_set_callback(subreq, dns_udp_request_get_reply, req);
+ return req;
+}
+
+static void dns_udp_request_get_reply(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(subreq,
+ struct tevent_req);
+ struct dns_udp_request_state *state = tevent_req_data(req,
+ struct dns_udp_request_state);
+ ssize_t len;
+ int err = 0;
+
+ len = tdgram_sendto_recv(subreq, &err);
+ TALLOC_FREE(subreq);
+
+ if (len == -1 && err != 0) {
+ tevent_req_error(req, err);
+ return;
+ }
+
+ if (len != state->query_len) {
+ tevent_req_error(req, EIO);
+ return;
+ }
+
+ subreq = tdgram_recvfrom_send(state, state->ev, state->dgram);
+ if (tevent_req_nomem(subreq, req)) {
+ return;
+ }
+
+ tevent_req_set_callback(subreq, dns_udp_request_done, req);
+}
+
+static void dns_udp_request_done(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(subreq,
+ struct tevent_req);
+ struct dns_udp_request_state *state = tevent_req_data(req,
+ struct dns_udp_request_state);
+
+ ssize_t len;
+ int err = 0;
+
+ len = tdgram_recvfrom_recv(subreq, &err, state, &state->reply, NULL);
+ TALLOC_FREE(subreq);
+
+ if (len == -1 && err != 0) {
+ tevent_req_error(req, err);
+ return;
+ }
+
+ state->reply_len = len;
+ dump_data(10, state->reply, state->reply_len);
+ tevent_req_done(req);
+}
+
+static int dns_udp_request_recv(struct tevent_req *req,
+ TALLOC_CTX *mem_ctx,
+ uint8_t **reply,
+ size_t *reply_len)
+{
+ struct dns_udp_request_state *state = tevent_req_data(req,
+ struct dns_udp_request_state);
+ int err;
+
+ if (tevent_req_is_unix_error(req, &err)) {
+ tevent_req_received(req);
+ return err;
+ }
+
+ *reply = talloc_move(mem_ctx, &state->reply);
+ *reply_len = state->reply_len;
+ tevent_req_received(req);
+
+ return 0;
+}
+
+struct dns_tcp_request_state {
+ struct tevent_context *ev;
+ struct tstream_context *stream;
+ const uint8_t *query;
+ size_t query_len;
+
+ uint8_t dns_msglen_hdr[2];
+ struct iovec iov[2];
+
+ size_t nread;
+ uint8_t *reply;
+};
+
+static void dns_tcp_request_connected(struct tevent_req *subreq);
+static void dns_tcp_request_sent(struct tevent_req *subreq);
+static int dns_tcp_request_next_vector(struct tstream_context *stream,
+ void *private_data,
+ TALLOC_CTX *mem_ctx,
+ struct iovec **_vector,
+ size_t *_count);
+static void dns_tcp_request_received(struct tevent_req *subreq);
+
+static struct tevent_req *dns_tcp_request_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ const char *server_addr_string,
+ const uint8_t *query,
+ size_t query_len)
+{
+ struct tevent_req *req, *subreq;
+ struct dns_tcp_request_state *state;
+ struct tsocket_address *local, *remote;
+ int ret;
+
+ req = tevent_req_create(mem_ctx, &state,
+ struct dns_tcp_request_state);
+ if (req == NULL) {
+ return NULL;
+ }
+ state->ev = ev;
+ state->query = query;
+ state->query_len = query_len;
+
+ if (query_len > UINT16_MAX) {
+ tevent_req_error(req, EMSGSIZE);
+ return tevent_req_post(req, ev);
+ }
+
+ ret = tsocket_address_inet_from_strings(state, "ip", NULL, 0, &local);
+ if (ret != 0) {
+ tevent_req_error(req, errno);
+ return tevent_req_post(req, ev);
+ }
+
+ ret = tsocket_address_inet_from_hostport_strings(
+ state, "ip", server_addr_string, DNS_SERVICE_PORT, &remote);
+ if (ret != 0) {
+ tevent_req_error(req, errno);
+ return tevent_req_post(req, ev);
+ }
+
+ subreq = tstream_inet_tcp_connect_send(state, state->ev,
+ local, remote);
+ if (tevent_req_nomem(subreq, req)) {
+ return tevent_req_post(req, ev);
+ }
+ tevent_req_set_callback(subreq, dns_tcp_request_connected, req);
+
+ return req;
+}
+
+static void dns_tcp_request_connected(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(
+ subreq, struct tevent_req);
+ struct dns_tcp_request_state *state = tevent_req_data(
+ req, struct dns_tcp_request_state);
+ int ret, err;
+
+ ret = tstream_inet_tcp_connect_recv(subreq, &err, state,
+ &state->stream, NULL);
+ TALLOC_FREE(subreq);
+ if (ret == -1) {
+ tevent_req_error(req, err);
+ return;
+ }
+
+ RSSVAL(state->dns_msglen_hdr, 0, state->query_len);
+ state->iov[0] = (struct iovec) {
+ .iov_base = state->dns_msglen_hdr,
+ .iov_len = sizeof(state->dns_msglen_hdr)
+ };
+ state->iov[1] = (struct iovec) {
+ .iov_base = discard_const_p(void, state->query),
+ .iov_len = state->query_len
+ };
+
+ subreq = tstream_writev_send(state, state->ev, state->stream,
+ state->iov, ARRAY_SIZE(state->iov));
+ if (tevent_req_nomem(subreq, req)) {
+ return;
+ }
+ tevent_req_set_callback(subreq, dns_tcp_request_sent, req);
+}
+
+static void dns_tcp_request_sent(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(
+ subreq, struct tevent_req);
+ struct dns_tcp_request_state *state = tevent_req_data(
+ req, struct dns_tcp_request_state);
+ int ret, err;
+
+ ret = tstream_writev_recv(subreq, &err);
+ TALLOC_FREE(subreq);
+ if (ret == -1) {
+ tevent_req_error(req, err);
+ return;
+ }
+
+ subreq = tstream_readv_pdu_send(state, state->ev, state->stream,
+ dns_tcp_request_next_vector, state);
+ if (tevent_req_nomem(subreq, req)) {
+ return;
+ }
+ tevent_req_set_callback(subreq, dns_tcp_request_received, req);
+}
+
+static int dns_tcp_request_next_vector(struct tstream_context *stream,
+ void *private_data,
+ TALLOC_CTX *mem_ctx,
+ struct iovec **_vector,
+ size_t *_count)
+{
+ struct dns_tcp_request_state *state = talloc_get_type_abort(
+ private_data, struct dns_tcp_request_state);
+ struct iovec *vector;
+ uint16_t msglen;
+
+ if (state->nread == 0) {
+ vector = talloc_array(mem_ctx, struct iovec, 1);
+ if (vector == NULL) {
+ return -1;
+ }
+ vector[0] = (struct iovec) {
+ .iov_base = state->dns_msglen_hdr,
+ .iov_len = sizeof(state->dns_msglen_hdr)
+ };
+ state->nread = sizeof(state->dns_msglen_hdr);
+
+ *_vector = vector;
+ *_count = 1;
+ return 0;
+ }
+
+ if (state->nread == sizeof(state->dns_msglen_hdr)) {
+ msglen = RSVAL(state->dns_msglen_hdr, 0);
+
+ state->reply = talloc_array(state, uint8_t, msglen);
+ if (state->reply == NULL) {
+ return -1;
+ }
+
+ vector = talloc_array(mem_ctx, struct iovec, 1);
+ if (vector == NULL) {
+ return -1;
+ }
+ vector[0] = (struct iovec) {
+ .iov_base = state->reply,
+ .iov_len = msglen
+ };
+ state->nread += msglen;
+
+ *_vector = vector;
+ *_count = 1;
+ return 0;
+ }
+
+ *_vector = NULL;
+ *_count = 0;
+ return 0;
+}
+
+static void dns_tcp_request_received(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(
+ subreq, struct tevent_req);
+ int ret, err;
+
+ ret = tstream_readv_pdu_recv(subreq, &err);
+ TALLOC_FREE(subreq);
+ if (ret == -1) {
+ tevent_req_error(req, err);
+ return;
+ }
+
+ tevent_req_done(req);
+}
+
+static int dns_tcp_request_recv(struct tevent_req *req,
+ TALLOC_CTX *mem_ctx,
+ uint8_t **reply,
+ size_t *reply_len)
+{
+ struct dns_tcp_request_state *state = tevent_req_data(
+ req, struct dns_tcp_request_state);
+ int err;
+
+ if (tevent_req_is_unix_error(req, &err)) {
+ tevent_req_received(req);
+ return err;
+ }
+
+ *reply_len = talloc_array_length(state->reply);
+ *reply = talloc_move(mem_ctx, &state->reply);
+ tevent_req_received(req);
+
+ return 0;
+}
+
+struct dns_cli_request_state {
+ struct tevent_context *ev;
+ const char *nameserver;
+
+ uint16_t req_id;
+
+ DATA_BLOB query;
+
+ struct dns_name_packet *reply;
+};
+
+static void dns_cli_request_udp_done(struct tevent_req *subreq);
+static void dns_cli_request_tcp_done(struct tevent_req *subreq);
+
+struct tevent_req *dns_cli_request_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ const char *nameserver,
+ const char *name,
+ enum dns_qclass qclass,
+ enum dns_qtype qtype)
+{
+ struct tevent_req *req, *subreq;
+ struct dns_cli_request_state *state;
+ struct dns_name_question question;
+ struct dns_name_packet out_packet;
+ enum ndr_err_code ndr_err;
+
+ req = tevent_req_create(mem_ctx, &state,
+ struct dns_cli_request_state);
+ if (req == NULL) {
+ return NULL;
+ }
+ state->ev = ev;
+ state->nameserver = nameserver;
+
+ DBG_DEBUG("Asking %s for %s/%d/%d via UDP\n", nameserver,
+ name, (int)qclass, (int)qtype);
+
+ generate_random_buffer((uint8_t *)&state->req_id,
+ sizeof(state->req_id));
+
+ question = (struct dns_name_question) {
+ .name = discard_const_p(char, name),
+ .question_type = qtype, .question_class = qclass
+ };
+
+ out_packet = (struct dns_name_packet) {
+ .id = state->req_id,
+ .operation = DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED,
+ .qdcount = 1,
+ .questions = &question
+ };
+
+ ndr_err = ndr_push_struct_blob(
+ &state->query, state, &out_packet,
+ (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
+ if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+ tevent_req_error(req, ndr_map_error2errno(ndr_err));
+ return tevent_req_post(req, ev);
+ }
+
+ subreq = dns_udp_request_send(state, state->ev, state->nameserver,
+ state->query.data, state->query.length);
+ if (tevent_req_nomem(subreq, req)) {
+ return tevent_req_post(req, ev);
+ }
+ tevent_req_set_callback(subreq, dns_cli_request_udp_done, req);
+ return req;
+}
+
+static void dns_cli_request_udp_done(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(
+ subreq, struct tevent_req);
+ struct dns_cli_request_state *state = tevent_req_data(
+ req, struct dns_cli_request_state);
+ DATA_BLOB reply;
+ enum ndr_err_code ndr_err;
+ uint16_t reply_id, operation;
+ int ret;
+
+ ret = dns_udp_request_recv(subreq, state, &reply.data, &reply.length);
+ TALLOC_FREE(subreq);
+ if (tevent_req_error(req, ret)) {
+ return;
+ }
+
+ if (reply.length < 4) {
+ DBG_DEBUG("Short DNS packet: length=%zu\n", reply.length);
+ tevent_req_error(req, EINVAL);
+ return;
+ }
+
+ reply_id = PULL_BE_U16(reply.data, 0);
+ if (reply_id != state->req_id) {
+ DBG_DEBUG("Got id %"PRIu16", expected %"PRIu16"\n",
+ state->reply->id, state->req_id);
+ tevent_req_error(req, ENOMSG);
+ return;
+ }
+
+ operation = PULL_BE_U16(reply.data, 2);
+ if ((operation & DNS_FLAG_TRUNCATION) != 0) {
+ DBG_DEBUG("Reply was truncated, retrying TCP\n");
+ subreq = dns_tcp_request_send(
+ state,
+ state->ev,
+ state->nameserver,
+ state->query.data,
+ state->query.length);
+ if (tevent_req_nomem(subreq, req)) {
+ return;
+ }
+ tevent_req_set_callback(subreq, dns_cli_request_tcp_done, req);
+ return;
+ }
+
+ state->reply = talloc(state, struct dns_name_packet);
+ if (tevent_req_nomem(state->reply, req)) {
+ return;
+ }
+
+ ndr_err = ndr_pull_struct_blob(
+ &reply, state->reply, state->reply,
+ (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
+ if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+ tevent_req_error(req, ndr_map_error2errno(ndr_err));
+ return;
+ }
+ TALLOC_FREE(reply.data);
+
+ tevent_req_done(req);
+}
+
+static void dns_cli_request_tcp_done(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(
+ subreq, struct tevent_req);
+ struct dns_cli_request_state *state = tevent_req_data(
+ req, struct dns_cli_request_state);
+ DATA_BLOB reply;
+ enum ndr_err_code ndr_err;
+ int ret;
+
+ ret = dns_tcp_request_recv(subreq, state, &reply.data, &reply.length);
+ TALLOC_FREE(subreq);
+ if (tevent_req_error(req, ret)) {
+ return;
+ }
+
+ state->reply = talloc(state, struct dns_name_packet);
+ if (tevent_req_nomem(state->reply, req)) {
+ return;
+ }
+
+ ndr_err = ndr_pull_struct_blob(
+ &reply, state->reply, state->reply,
+ (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
+ if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+ tevent_req_error(req, ndr_map_error2errno(ndr_err));
+ return;
+ }
+ TALLOC_FREE(reply.data);
+
+ if (state->reply->id != state->req_id) {
+ DBG_DEBUG("Got id %"PRIu16", expected %"PRIu16"\n",
+ state->reply->id, state->req_id);
+ tevent_req_error(req, ENOMSG);
+ return;
+ }
+
+ DBG_DEBUG("Got op=%x %"PRIu16"/%"PRIu16"/%"PRIu16"/%"PRIu16
+ " recs\n", (int)state->reply->operation,
+ state->reply->qdcount, state->reply->ancount,
+ state->reply->nscount, state->reply->nscount);
+
+ tevent_req_done(req);
+}
+
+int dns_cli_request_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
+ struct dns_name_packet **reply)
+{
+ struct dns_cli_request_state *state = tevent_req_data(
+ req, struct dns_cli_request_state);
+ int err;
+
+ if (tevent_req_is_unix_error(req, &err)) {
+ return err;
+ }
+ *reply = talloc_move(mem_ctx, &state->reply);
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-07 16:30:21 +0000