diff options
Diffstat (limited to '')
| -rw-r--r-- | libcli/dns/dns.c | 591 | ||||
| -rw-r--r-- | libcli/dns/dns.h | 64 | ||||
| -rw-r--r-- | libcli/dns/dns_lookup.c | 374 | ||||
| -rw-r--r-- | libcli/dns/dns_lookup.h | 48 | ||||
| -rw-r--r-- | libcli/dns/dns_lookuptest.c | 55 | ||||
| -rw-r--r-- | libcli/dns/libdns.h | 43 | ||||
| -rw-r--r-- | libcli/dns/resolvconf.c | 123 | ||||
| -rw-r--r-- | libcli/dns/resolvconf.h | 37 | ||||
| -rw-r--r-- | libcli/dns/resolvconftest.c | 82 | ||||
| -rw-r--r-- | libcli/dns/wscript_build | 21 |
10 files changed, 1438 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; +} diff --git a/libcli/dns/dns.h b/libcli/dns/dns.h new file mode 100644 index 0000000..34a6cf5 --- /dev/null +++ b/libcli/dns/dns.h @@ -0,0 +1,64 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Gerald Carter 2006. + * Copyright (C) Andrew Bartlett 2011 + * + * 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/>. + */ + +/* DNS query section in replies */ + +#ifndef __LIBCLI_DNS_DNS_H__ +#define __LIBCLI_DNS_DNS_H__ + +#include "replace.h" +#include "system/network.h" + +struct dns_query { + const char *hostname; + uint16_t type; + uint16_t in_class; +}; + +/* DNS RR record in reply */ + +struct dns_rr { + const char *hostname; + uint16_t type; + uint16_t in_class; + uint32_t ttl; + uint16_t rdatalen; + uint8_t *rdata; +}; + +/* SRV records */ + +struct dns_rr_srv { + const char *hostname; + uint16_t priority; + uint16_t weight; + uint16_t port; + size_t num_ips; + struct sockaddr_storage *ss_s; /* support multi-homed hosts */ +}; + +/* NS records */ + +struct dns_rr_ns { + const char *hostname; + struct sockaddr_storage ss; +}; + +#endif diff --git a/libcli/dns/dns_lookup.c b/libcli/dns/dns_lookup.c new file mode 100644 index 0000000..cb0ede8 --- /dev/null +++ b/libcli/dns/dns_lookup.c @@ -0,0 +1,374 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Volker Lendecke 2018 + * + * 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 "libcli/dns/dns_lookup.h" +#include "libcli/dns/resolvconf.h" +#include "libcli/dns/libdns.h" +#include "lib/util/tevent_unix.h" +#include "lib/util/samba_util.h" +#include "lib/util/debug.h" + +struct dns_lookup_state { + struct tevent_context *ev; + const char *name; + enum dns_qclass qclass; + enum dns_qtype qtype; + + char **nameservers; + size_t num_nameservers; + size_t num_sent; + + struct tevent_req **dns_subreqs; + struct tevent_req *wait_subreq; + + struct dns_name_packet *reply; +}; + +static int dns_lookup_send_next(struct tevent_req *req); + +static void dns_lookup_done(struct tevent_req *subreq); +static void dns_lookup_waited(struct tevent_req *subreq); + +struct tevent_req *dns_lookup_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + FILE *resolv_conf_fp, + const char *name, + enum dns_qclass qclass, + enum dns_qtype qtype) +{ + struct tevent_req *req; + struct dns_lookup_state *state; + FILE *fp = resolv_conf_fp; + int ret; + + req = tevent_req_create(mem_ctx, &state, struct dns_lookup_state); + if (req == NULL) { + return NULL; + } + state->ev = ev; + state->name = name; + state->qclass = qclass; + state->qtype = qtype; + + if (resolv_conf_fp == NULL) { + const char *resolvconf = "/etc/resolv.conf"; + +#ifdef ENABLE_SELFTEST + { + const char *envvar = getenv("RESOLV_CONF"); + if (envvar != NULL) { + resolvconf = envvar; + } + } +#endif + + fp = fopen(resolvconf, "r"); + if (fp == NULL) { + tevent_req_error(req, errno); + return tevent_req_post(req, ev); + } + } + + ret = parse_resolvconf_fp( + fp, + state, + &state->nameservers, + &state->num_nameservers); + + if (resolv_conf_fp == NULL) { + fclose(fp); + } + + if (ret != 0) { + tevent_req_error(req, ret); + return tevent_req_post(req, ev); + } + + if (state->num_nameservers == 0) { + /* + * glibc's getaddrinfo returns EAI_AGAIN when no + * nameservers are configured. EAGAIN seems closest. + */ + tevent_req_error(req, EAGAIN); + return tevent_req_post(req, ev); + } + + state->dns_subreqs = talloc_zero_array( + state, + struct tevent_req *, + state->num_nameservers); + + if (tevent_req_nomem(state->dns_subreqs, req)) { + return tevent_req_post(req, ev); + } + + ret = dns_lookup_send_next(req); + if (tevent_req_error(req, ret)) { + return tevent_req_post(req, ev); + } + + return req; +} + +static int dns_lookup_send_next(struct tevent_req *req) +{ + struct dns_lookup_state *state = tevent_req_data( + req, struct dns_lookup_state); + + DBG_DEBUG("Sending DNS request #%zu to %s\n", + state->num_sent, + state->nameservers[state->num_sent]); + + state->dns_subreqs[state->num_sent] = dns_cli_request_send( + state->dns_subreqs, + state->ev, + state->nameservers[state->num_sent], + state->name, + state->qclass, + state->qtype); + + if (state->dns_subreqs[state->num_sent] == NULL) { + return ENOMEM; + } + tevent_req_set_callback(state->dns_subreqs[state->num_sent], + dns_lookup_done, + req); + state->num_sent += 1; + + if (state->num_sent == state->num_nameservers) { + /* + * No more nameservers left + */ + DBG_DEBUG("cancelling wait_subreq\n"); + TALLOC_FREE(state->wait_subreq); + return 0; + } + + if (state->wait_subreq != NULL) { + /* + * This can happen if we fire the next request upon + * dns_cli_request returning a network-level error + */ + return 0; + } + + state->wait_subreq = tevent_wakeup_send( + state, + state->ev, + tevent_timeval_current_ofs(1, 0)); + if (state->wait_subreq == NULL) { + return ENOMEM; + } + tevent_req_set_callback(state->wait_subreq, dns_lookup_waited, req); + + return 0; +} + +static void dns_lookup_done(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct dns_lookup_state *state = tevent_req_data( + req, struct dns_lookup_state); + int dns_cli_request_ret; + size_t i; + + dns_cli_request_ret = dns_cli_request_recv( + subreq, + state, + &state->reply); + + for (i = 0; i < state->num_nameservers; i++) { + if (state->dns_subreqs[i] == subreq) { + break; + } + } + + TALLOC_FREE(subreq); + + if (i == state->num_nameservers) { + /* should never happen */ + DBG_WARNING("Failed to find subreq"); + tevent_req_error(req, EINVAL); + return; + } + state->dns_subreqs[i] = NULL; + + if (dns_cli_request_ret == 0) { + /* + * Success, cancel everything else + */ + TALLOC_FREE(state->dns_subreqs); + TALLOC_FREE(state->wait_subreq); + tevent_req_done(req); + return; + } + + DBG_DEBUG("dns_cli_request[%zu] returned %s\n", i, + strerror(dns_cli_request_ret)); + + if (state->num_sent < state->num_nameservers) { + /* + * We have a nameserver left to try + */ + int ret; + + ret = dns_lookup_send_next(req); + if (tevent_req_error(req, ret)) { + return; + } + } + + DBG_DEBUG("looking for outstanding requests\n"); + + for (i = 0; i<state->num_nameservers; i++) { + if (state->dns_subreqs[i] != NULL) { + break; + } + } + + DBG_DEBUG("i=%zu, num_nameservers=%zu\n", + i, state->num_nameservers); + + if (i == state->num_nameservers) { + /* + * Report the lower-level error if we have nothing + * outstanding anymore + */ + tevent_req_error(req, dns_cli_request_ret); + return; + } + + /* + * Do nothing: We have other nameservers that might come back + * with something good. + */ +} + +static void dns_lookup_waited(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct dns_lookup_state *state = tevent_req_data( + req, struct dns_lookup_state); + int ret; + bool ok; + + DBG_DEBUG("waited\n"); + + ok = tevent_wakeup_recv(subreq); + TALLOC_FREE(subreq); + if (!ok) { + tevent_req_oom(req); + return; + } + state->wait_subreq = NULL; + + ret = dns_lookup_send_next(req); + if (tevent_req_error(req, ret)) { + return; + } + + /* + * dns_lookup_send_next() has already triggered the next wakeup + */ +} + +int dns_lookup_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx, + struct dns_name_packet **reply) +{ + struct dns_lookup_state *state = tevent_req_data( + req, struct dns_lookup_state); + int err; + + if (tevent_req_is_unix_error(req, &err)) { + return err; + } + + *reply = talloc_move(mem_ctx, &state->reply); + + tevent_req_received(req); + return 0; +} + +int dns_lookup(FILE *resolv_conf_fp, + const char *name, + enum dns_qclass qclass, + enum dns_qtype qtype, + TALLOC_CTX *mem_ctx, + struct dns_name_packet **reply) +{ + struct tevent_context *ev; + struct tevent_req *req; + int ret = ENOMEM; + + ev = samba_tevent_context_init(mem_ctx); + if (ev == NULL) { + goto fail; + } + req = dns_lookup_send(ev, ev, resolv_conf_fp, name, qclass, qtype); + if (req == NULL) { + goto fail; + } + if (!tevent_req_poll_unix(req, ev, &ret)) { + goto fail; + } + ret = dns_lookup_recv(req, mem_ctx, reply); +fail: + TALLOC_FREE(ev); + return ret; +} + +bool dns_res_rec_get_sockaddr(const struct dns_res_rec *rec, + struct sockaddr_storage *addr) +{ + sa_family_t family; + const char *src; + void *dst; + int ret; + + switch (rec->rr_type) { + case DNS_QTYPE_A: + family = AF_INET; + src = rec->rdata.ipv4_record; + dst = &(((struct sockaddr_in *)addr)->sin_addr); + break; +#ifdef HAVE_IPV6 + case DNS_QTYPE_AAAA: + family = AF_INET6; + src = rec->rdata.ipv6_record; + dst = &(((struct sockaddr_in6 *)addr)->sin6_addr); + break; +#endif + default: + /* We only care about IP addresses */ + return false; + } + + *addr = (struct sockaddr_storage) { .ss_family = family }; + + ret = inet_pton(family, src, dst); + if (ret != 1) { + DBG_DEBUG("inet_pton(%s) failed\n", src); + return false; + } + + return true; +} diff --git a/libcli/dns/dns_lookup.h b/libcli/dns/dns_lookup.h new file mode 100644 index 0000000..0c05e04 --- /dev/null +++ b/libcli/dns/dns_lookup.h @@ -0,0 +1,48 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Volker Lendecke 2018 + * + * 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/>. + */ + +#ifndef __LIBCLI_DNS_DNS_LOOKUP_H__ +#define __LIBCLI_DNS_DNS_LOOKUP_H__ + +#include "replace.h" +#include "system/network.h" +#include <tevent.h> +#include "lib/util/data_blob.h" +#include "lib/util/time.h" +#include "librpc/gen_ndr/dns.h" + +struct tevent_req *dns_lookup_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + FILE *resolv_conf_fp, + const char *name, + enum dns_qclass qclass, + enum dns_qtype qtype); +int dns_lookup_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx, + struct dns_name_packet **reply); +int dns_lookup(FILE *resolv_conf_fp, + const char *name, + enum dns_qclass qclass, + enum dns_qtype qtype, + TALLOC_CTX *mem_ctx, + struct dns_name_packet **reply); + +bool dns_res_rec_get_sockaddr(const struct dns_res_rec *rec, + struct sockaddr_storage *addr); + +#endif diff --git a/libcli/dns/dns_lookuptest.c b/libcli/dns/dns_lookuptest.c new file mode 100644 index 0000000..c8e0343 --- /dev/null +++ b/libcli/dns/dns_lookuptest.c @@ -0,0 +1,55 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Volker Lendecke 2018 + * + * 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 <stdio.h> +#include <string.h> +#include <talloc.h> +#include <errno.h> +#include "libcli/dns/dns_lookup.h" +#include "lib/util/debug.h" + +static int dns_lookuptest1(void) +{ + struct dns_name_packet *reply = NULL; + int ret; + + ret = dns_lookup(NULL, "www.samba.org", DNS_QCLASS_IN, DNS_QTYPE_A, + NULL, &reply); + if (ret != 0) { + fprintf(stderr, "dns_lookup failed: %s\n", strerror(ret)); + return ret; + } + + TALLOC_FREE(reply); + return 0; +} + +int main(int argc, const char *argv[]) { + int ret; + + setup_logging(argv[0], DEBUG_DEFAULT_STDERR); + debug_parse_levels("10"); + + ret = dns_lookuptest1(); + if (ret != 0) { + return 1; + } + + return 0; +} diff --git a/libcli/dns/libdns.h b/libcli/dns/libdns.h new file mode 100644 index 0000000..15ca257 --- /dev/null +++ b/libcli/dns/libdns.h @@ -0,0 +1,43 @@ +/* + Unix SMB/CIFS implementation. + + Small async DNS library for Samba with socketwrapper support + + Copyright (C) 2012 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/>. +*/ + +#ifndef __LIBDNS_H__ +#define __LIBDNS_H__ + +#include "lib/util/data_blob.h" +#include "lib/util/time.h" +#include "librpc/gen_ndr/dns.h" + +/* + * DNS request with fallback to TCP on truncation + */ + +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); +int dns_cli_request_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx, + struct dns_name_packet **reply); + + +#endif /*__LIBDNS_H__*/ diff --git a/libcli/dns/resolvconf.c b/libcli/dns/resolvconf.c new file mode 100644 index 0000000..5cf8b4e --- /dev/null +++ b/libcli/dns/resolvconf.c @@ -0,0 +1,123 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Volker Lendecke 2018 + * + * 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 <stdio.h> +#include <errno.h> +#include "libcli/dns/resolvconf.h" +#include "lib/util/memory.h" + +int parse_resolvconf_fp( + FILE *fp, + TALLOC_CTX *mem_ctx, + char ***pnameservers, + size_t *pnum_nameservers) +{ + char *line = NULL; + size_t len = 0; + char **nameservers = NULL; + size_t num_nameservers = 0; + int ret = 0; + + while (true) { + char *saveptr = NULL, *option = NULL, *ns = NULL; + char **tmp = NULL; + ssize_t n = 0; + + n = getline(&line, &len, fp); + if (n < 0) { + if (!feof(fp)) { + /* real error */ + ret = errno; + } + break; + } + if ((n > 0) && (line[n-1] == '\n')) { + line[n-1] = '\0'; + } + + if ((line[0] == '#') || (line[0] == ';')) { + continue; + } + + option = strtok_r(line, " \t", &saveptr); + if (option == NULL) { + continue; + } + + if (strcmp(option, "nameserver") != 0) { + continue; + } + + ns = strtok_r(NULL, " \t", &saveptr); + if (ns == NULL) { + continue; + } + + tmp = talloc_realloc( + mem_ctx, + nameservers, + char *, + num_nameservers+1); + if (tmp == NULL) { + ret = ENOMEM; + break; + } + nameservers = tmp; + + nameservers[num_nameservers] = talloc_strdup(nameservers, ns); + if (nameservers[num_nameservers] == NULL) { + ret = ENOMEM; + break; + } + num_nameservers += 1; + } + + SAFE_FREE(line); + + if (ret == 0) { + *pnameservers = nameservers; + *pnum_nameservers = num_nameservers; + } else { + TALLOC_FREE(nameservers); + } + + return ret; +} + +int parse_resolvconf( + const char *resolvconf, + TALLOC_CTX *mem_ctx, + char ***pnameservers, + size_t *pnum_nameservers) +{ + FILE *fp; + int ret; + + fp = fopen(resolvconf ? resolvconf : "/etc/resolv.conf", "r"); + if (fp == NULL) { + return errno; + } + + ret = parse_resolvconf_fp(fp, mem_ctx, pnameservers, pnum_nameservers); + + fclose(fp); + + return ret; +} diff --git a/libcli/dns/resolvconf.h b/libcli/dns/resolvconf.h new file mode 100644 index 0000000..3ea258c --- /dev/null +++ b/libcli/dns/resolvconf.h @@ -0,0 +1,37 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Volker Lendecke 2018 + * + * 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/>. + */ + +#ifndef __LIBCLI_DNS_RESOLVCONF_H__ +#define __LIBCLI_DNS_RESOLVCONF_H__ + +#include <talloc.h> +#include <stdio.h> + +int parse_resolvconf_fp( + FILE *fp, + TALLOC_CTX *mem_ctx, + char ***pnameservers, + size_t *pnum_nameservers); +int parse_resolvconf( + const char *resolvconf, + TALLOC_CTX *mem_ctx, + char ***pnameservers, + size_t *pnum_nameservers); + +#endif diff --git a/libcli/dns/resolvconftest.c b/libcli/dns/resolvconftest.c new file mode 100644 index 0000000..6395264 --- /dev/null +++ b/libcli/dns/resolvconftest.c @@ -0,0 +1,82 @@ +/* + * Unix SMB/CIFS implementation. + * Internal DNS query structures + * Copyright (C) Volker Lendecke 2018 + * + * 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 <stdio.h> +#include <string.h> +#include <talloc.h> +#include <errno.h> +#include "libcli/dns/resolvconf.h" +#include "lib/util/memory.h" + +static int resolvconftest1(void) +{ + const char *content = + "#foo\nbar\nnameserver 1.2.3.4\nnameserver 2.3.4.5"; + char *file; + FILE *fp; + int ret; + char **nameservers; + size_t num_nameservers; + + file = strdup(content); + if (file == NULL) { + perror("strdup failed"); + return ENOMEM; + } + fp = fmemopen(file, strlen(file), "r"); + if (fp == NULL) { + perror("fmemopen failed"); + return errno; + } + + ret = parse_resolvconf_fp(fp, NULL, &nameservers, &num_nameservers); + if (ret != 0) { + fprintf(stderr, "parse_resolvconf_fp failed: %s\n", + strerror(ret)); + return ret; + } + + if (num_nameservers != 2) { + fprintf(stderr, "expected 2 nameservers, got %zu\n", + num_nameservers); + return EIO; + } + if ((strcmp(nameservers[0], "1.2.3.4") != 0) || + (strcmp(nameservers[1], "2.3.4.5") != 0)) { + fprintf(stderr, "got wrong nameservers\n"); + return EIO; + } + + TALLOC_FREE(nameservers); + fclose(fp); + SAFE_FREE(file); + + return 0; +} + +int main(void) { + int ret; + + ret = resolvconftest1(); + if (ret != 0) { + return 1; + } + + return 0; +} diff --git a/libcli/dns/wscript_build b/libcli/dns/wscript_build new file mode 100644 index 0000000..2d90aa7 --- /dev/null +++ b/libcli/dns/wscript_build @@ -0,0 +1,21 @@ +#!/usr/bin/env python + +bld.SAMBA_LIBRARY('clidns', + source='dns.c resolvconf.c', + public_deps='LIBTSOCKET tevent-util ndr-standard', + private_library=True) + +bld.SAMBA_BINARY('resolvconftest', + source='resolvconftest.c', + deps='clidns', + enabled=bld.CONFIG_SET('HAVE_FMEMOPEN'), + for_selftest=True) + +bld.SAMBA_SUBSYSTEM('dns_lookup', + source='dns_lookup.c', + public_deps='clidns') + +bld.SAMBA_BINARY('dns_lookuptest', + source='dns_lookuptest.c', + deps='dns_lookup', + for_selftest=True) |