source4/dns_server/dns_server.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server startup
   5
   6    Copyright (C) 2010 Kai Blin  <kai@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/service_task.h"
  24 #include "smbd/service.h"
  25 #include "smbd/service_stream.h"
  26 #include "smbd/process_model.h"
  27 #include "lib/events/events.h"
  28 #include "lib/socket/socket.h"
  29 #include "lib/tsocket/tsocket.h"
  30 #include "libcli/util/tstream.h"
  31 #include "system/network.h"
  32 #include "lib/stream/packet.h"
  33 #include "lib/socket/netif.h"
  34 #include "dns_server/dns_server.h"
  35 #include "param/param.h"
  36
  37 /* hold information about one dns socket */
  38 struct dns_socket {
  39         struct dns_server *dns;
  40         struct tsocket_address *local_address;
  41 };
  42
  43 struct dns_udp_socket {
  44         struct dns_socket *dns_socket;
  45         struct tdgram_context *dgram;
  46         struct tevent_queue *send_queue;
  47 };
  48
  49 /*
  50   state of an open tcp connection
  51 */
  52 struct dns_tcp_connection {
  53         /* stream connection we belong to */
  54         struct stream_connection *conn;
  55
  56         /* the dns_server the connection belongs to */
  57         struct dns_socket *dns_socket;
  58
  59         struct tstream_context *tstream;
  60
  61         struct tevent_queue *send_queue;
  62 };
  63
  64 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  65 {
  66         stream_terminate_connection(dnsconn->conn, reason);
  67 }
  68
  69 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  70 {
  71         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  72                                                              struct dns_tcp_connection);
  73         /* this should never be triggered! */
  74         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  75 }
  76
  77 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  78 {
  79         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  80                                                              struct dns_tcp_connection);
  81         /* this should never be triggered! */
  82         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
  83 }
  84
  85 bool dns_process(struct dns_server *dns,
  86                  TALLOC_CTX *mem_ctx,
  87                  DATA_BLOB *in,
  88                  DATA_BLOB *out)
  89 {
  90         DEBUG(0, ("FIXME: actually process DNS packet here\n"));
  91         return true;
  92 }
  93
  94 struct dns_tcp_call {
  95         struct dns_tcp_connection *dns_conn;
  96         DATA_BLOB in;
  97         DATA_BLOB out;
  98         uint8_t out_hdr[4];
  99         struct iovec out_iov[2];
 100 };
 101
 102 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 103
 104 static void dns_tcp_call_loop(struct tevent_req *subreq)
 105 {
 106         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 107                                       struct dns_tcp_connection);
 108         struct dns_tcp_call *call;
 109         NTSTATUS status;
 110         bool ok;
 111
 112         call = talloc(dns_conn, struct dns_tcp_call);
 113         if (call == NULL) {
 114                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 115                                 "no memory for dns_tcp_call");
 116                 return;
 117         }
 118         call->dns_conn = dns_conn;
 119
 120         status = tstream_read_pdu_blob_recv(subreq,
 121                                             call,
 122                                             &call->in);
 123         TALLOC_FREE(subreq);
 124         if (!NT_STATUS_IS_OK(status)) {
 125                 const char *reason;
 126
 127                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 128                                          "tstream_read_pdu_blob_recv() - %s",
 129                                          nt_errstr(status));
 130                 if (!reason) {
 131                         reason = nt_errstr(status);
 132                 }
 133
 134                 dns_tcp_terminate_connection(dns_conn, reason);
 135                 return;
 136         }
 137
 138         DEBUG(10,("Received krb5 TCP packet of length %lu from %s\n",
 139                  (long) call->in.length,
 140                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 141
 142         /* skip length header */
 143         call->in.data +=4;
 144         call->in.length -= 4;
 145
 146         /* Call dns */
 147         ok = dns_process(dns_conn->dns_socket->dns, call, &call->in, &call->out);
 148         if (!ok) {
 149                 dns_tcp_terminate_connection(dns_conn,
 150                                 "dns_tcp_call_loop: process function failed");
 151                 return;
 152         }
 153
 154         /* First add the length of the out buffer */
 155         RSIVAL(call->out_hdr, 0, call->out.length);
 156         call->out_iov[0].iov_base = (char *) call->out_hdr;
 157         call->out_iov[0].iov_len = 4;
 158
 159         call->out_iov[1].iov_base = (char *) call->out.data;
 160         call->out_iov[1].iov_len = call->out.length;
 161
 162         subreq = tstream_writev_queue_send(call,
 163                                            dns_conn->conn->event.ctx,
 164                                            dns_conn->tstream,
 165                                            dns_conn->send_queue,
 166                                            call->out_iov, 2);
 167         if (subreq == NULL) {
 168                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 169                                 "no memory for tstream_writev_queue_send");
 170                 return;
 171         }
 172         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 173
 174         /*
 175          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 176          * packet_full_request_u32 provides the pdu length then.
 177          */
 178         subreq = tstream_read_pdu_blob_send(dns_conn,
 179                                             dns_conn->conn->event.ctx,
 180                                             dns_conn->tstream,
 181                                             4, /* initial_read_size */
 182                                             packet_full_request_u32,
 183                                             dns_conn);
 184         if (subreq == NULL) {
 185                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 186                                 "no memory for tstream_read_pdu_blob_send");
 187                 return;
 188         }
 189         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 190 }
 191
 192 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 193 {
 194         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 195                         struct dns_tcp_call);
 196         int sys_errno;
 197         int rc;
 198
 199         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 200         TALLOC_FREE(subreq);
 201         if (rc == -1) {
 202                 const char *reason;
 203
 204                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 205                                          "tstream_writev_queue_recv() - %d:%s",
 206                                          sys_errno, strerror(sys_errno));
 207                 if (!reason) {
 208                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 209                 }
 210
 211                 dns_tcp_terminate_connection(call->dns_conn, reason);
 212                 return;
 213         }
 214
 215         /* We don't care about errors */
 216
 217         talloc_free(call);
 218 }
 219
 220 /*
 221   called when we get a new connection
 222 */
 223 static void dns_tcp_accept(struct stream_connection *conn)
 224 {
 225         struct dns_socket *dns_socket;
 226         struct dns_tcp_connection *dns_conn;
 227         struct tevent_req *subreq;
 228         int rc;
 229
 230         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 231         if (dns_conn == NULL) {
 232                 stream_terminate_connection(conn,
 233                                 "dns_tcp_accept: out of memory");
 234                 return;
 235         }
 236
 237         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 238         if (dns_conn->send_queue == NULL) {
 239                 stream_terminate_connection(conn,
 240                                 "dns_tcp_accept: out of memory");
 241                 return;
 242         }
 243
 244         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 245
 246         TALLOC_FREE(conn->event.fde);
 247
 248         rc = tstream_bsd_existing_socket(dns_conn,
 249                         socket_get_fd(conn->socket),
 250                         &dns_conn->tstream);
 251         if (rc < 0) {
 252                 stream_terminate_connection(conn,
 253                                 "dns_tcp_accept: out of memory");
 254                 return;
 255         }
 256
 257         dns_conn->conn = conn;
 258         dns_conn->dns_socket = dns_socket;
 259         conn->private_data = dns_conn;
 260
 261         /*
 262          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 263          * packet_full_request_u32 provides the pdu length then.
 264          */
 265         subreq = tstream_read_pdu_blob_send(dns_conn,
 266                                             dns_conn->conn->event.ctx,
 267                                             dns_conn->tstream,
 268                                             4, /* initial_read_size */
 269                                             packet_full_request_u32,
 270                                             dns_conn);
 271         if (subreq == NULL) {
 272                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 273                                 "no memory for tstream_read_pdu_blob_send");
 274                 return;
 275         }
 276         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 277 }
 278
 279 static const struct stream_server_ops dns_tcp_stream_ops = {
 280         .name                   = "dns_tcp",
 281         .accept_connection      = dns_tcp_accept,
 282         .recv_handler           = dns_tcp_recv,
 283         .send_handler           = dns_tcp_send
 284 };
 285
 286 struct dns_udp_call {
 287         struct tsocket_address *src;
 288         DATA_BLOB in;
 289         DATA_BLOB out;
 290 };
 291
 292 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 293
 294 static void dns_udp_call_loop(struct tevent_req *subreq)
 295 {
 296         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 297                                       struct dns_udp_socket);
 298         struct dns_udp_call *call;
 299         uint8_t *buf;
 300         ssize_t len;
 301         int sys_errno;
 302         bool ok;
 303
 304         call = talloc(sock, struct dns_udp_call);
 305         if (call == NULL) {
 306                 talloc_free(call);
 307                 goto done;
 308         }
 309
 310         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 311                                    call, &buf, &call->src);
 312         TALLOC_FREE(subreq);
 313         if (len == -1) {
 314                 talloc_free(call);
 315                 goto done;
 316         }
 317
 318         call->in.data = buf;
 319         call->in.length = len;
 320
 321         DEBUG(10,("Received krb5 UDP packet of length %lu from %s\n",
 322                  (long)call->in.length,
 323                  tsocket_address_string(call->src, call)));
 324
 325         /* Call krb5 */
 326         ok = dns_process(sock->dns_socket->dns, call, &call->in, &call->out);
 327         if (!ok) {
 328                 talloc_free(call);
 329                 goto done;
 330         }
 331
 332         subreq = tdgram_sendto_queue_send(call,
 333                                           sock->dns_socket->dns->task->event_ctx,
 334                                           sock->dgram,
 335                                           sock->send_queue,
 336                                           call->out.data,
 337                                           call->out.length,
 338                                           call->src);
 339         if (subreq == NULL) {
 340                 talloc_free(call);
 341                 goto done;
 342         }
 343         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 344
 345 done:
 346         subreq = tdgram_recvfrom_send(sock,
 347                                       sock->dns_socket->dns->task->event_ctx,
 348                                       sock->dgram);
 349         if (subreq == NULL) {
 350                 task_server_terminate(sock->dns_socket->dns->task,
 351                                       "no memory for tdgram_recvfrom_send",
 352                                       true);
 353                 return;
 354         }
 355         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 356 }
 357
 358 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 359 {
 360         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 361                                        struct dns_udp_call);
 362         ssize_t ret;
 363         int sys_errno;
 364
 365         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 366
 367         /* We don't care about errors */
 368
 369         talloc_free(call);
 370 }
 371
 372 /*
 373   start listening on the given address
 374 */
 375 static NTSTATUS dns_add_socket(struct dns_server *dns,
 376                                const struct model_ops *model_ops,
 377                                const char *name,
 378                                const char *address,
 379                                uint16_t port)
 380 {
 381         struct dns_socket *dns_socket;
 382         struct dns_udp_socket *dns_udp_socket;
 383         struct tevent_req *udpsubreq;
 384         NTSTATUS status;
 385         int ret;
 386
 387         dns_socket = talloc(dns, struct dns_socket);
 388         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 389
 390         dns_socket->dns = dns;
 391
 392         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 393                                                 address, port,
 394                                                 &dns_socket->local_address);
 395         if (ret != 0) {
 396                 status = map_nt_error_from_unix(errno);
 397                 return status;
 398         }
 399
 400         status = stream_setup_socket(dns->task->event_ctx,
 401                                      dns->task->lp_ctx,
 402                                      model_ops,
 403                                      &dns_tcp_stream_ops,
 404                                      "ip", address, &port,
 405                                      lpcfg_socket_options(dns->task->lp_ctx),
 406                                      dns_socket);
 407         if (!NT_STATUS_IS_OK(status)) {
 408                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 409                          address, port, nt_errstr(status)));
 410                 talloc_free(dns_socket);
 411                 return status;
 412         }
 413
 414         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 415         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 416
 417         dns_udp_socket->dns_socket = dns_socket;
 418
 419         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 420                                      NULL,
 421                                      dns_udp_socket,
 422                                      &dns_udp_socket->dgram);
 423         if (ret != 0) {
 424                 status = map_nt_error_from_unix(errno);
 425                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 426                          address, port, nt_errstr(status)));
 427                 return status;
 428         }
 429
 430         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 431                                                          "dns_udp_send_queue");
 432         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 433
 434         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 435                                          dns->task->event_ctx,
 436                                          dns_udp_socket->dgram);
 437         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 438         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 439
 440         return NT_STATUS_OK;
 441 }
 442
 443 /*
 444   setup our listening sockets on the configured network interfaces
 445 */
 446 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 447                                        struct interface *ifaces)
 448 {
 449         const struct model_ops *model_ops;
 450         int num_interfaces;
 451         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 452         NTSTATUS status;
 453         int i;
 454
 455         /* within the dns task we want to be a single process, so
 456            ask for the single process model ops and pass these to the
 457            stream_setup_socket() call. */
 458         model_ops = process_model_startup(dns->task->event_ctx, "single");
 459         if (!model_ops) {
 460                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 461                 return NT_STATUS_INTERNAL_ERROR;
 462         }
 463
 464         num_interfaces = iface_count(ifaces);
 465
 466         for (i=0; i<num_interfaces; i++) {
 467                 const char *address = talloc_strdup(tmp_ctx, iface_n_ip(ifaces, i));
 468
 469                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 470                 NT_STATUS_NOT_OK_RETURN(status);
 471         }
 472
 473         talloc_free(tmp_ctx);
 474
 475         return NT_STATUS_OK;
 476 }
 477 static void dns_task_init(struct task_server *task)
 478 {
 479         struct dns_server *dns;
 480         NTSTATUS status;
 481         struct interface *ifaces;
 482
 483         switch (lpcfg_server_role(task->lp_ctx)) {
 484         case ROLE_STANDALONE:
 485                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 486                 return;
 487         case ROLE_DOMAIN_MEMBER:
 488                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 489                 return;
 490         case ROLE_DOMAIN_CONTROLLER:
 491                 /* Yes, we want a DNS */
 492                 break;
 493         }
 494
 495         load_interfaces(task, lpcfg_interfaces(task->lp_ctx), &ifaces);
 496
 497         if (iface_count(ifaces) == 0) {
 498                 task_server_terminate(task, "dns: no network interfaces configured", false);
 499                 return;
 500         }
 501
 502         task_server_set_title(task, "task[dns]");
 503
 504         dns = talloc(task, struct dns_server);
 505         if (dns == NULL) {
 506                 task_server_terminate(task, "dns: out of memory", true);
 507                 return;
 508         }
 509
 510         dns->task = task;
 511
 512         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 513         if (!NT_STATUS_IS_OK(status)) {
 514                 task_server_terminate(task, "dns failed to setup interfaces", true);
 515                 return;
 516         }
 517 }
 518
 519 NTSTATUS server_service_dns_init(void)
 520 {
 521         return register_server_service("dns", dns_task_init);
 522 }