source4/smbd/service_stream.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    helper functions for stream based servers
   5
   6    Copyright (C) Andrew Tridgell 2003-2005
   7    Copyright (C) Stefan (metze) Metzmacher      2004
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include <tevent.h>
  25 #include "process_model.h"
  26 #include "lib/util/server_id.h"
  27 #include "lib/messaging/irpc.h"
  28 #include "cluster/cluster.h"
  29 #include "param/param.h"
  30 #include "../lib/tsocket/tsocket.h"
  31 #include "lib/util/util_net.h"
  32
  33 /* size of listen() backlog in smbd */
  34 #define SERVER_LISTEN_BACKLOG 10
  35
  36
  37 /*
  38   private structure for a single listening stream socket
  39 */
  40 struct stream_socket {
  41         const struct stream_server_ops *ops;
  42         struct loadparm_context *lp_ctx;
  43         struct tevent_context *event_ctx;
  44         const struct model_ops *model_ops;
  45         struct socket_context *sock;
  46         void *private_data;
  47         void *process_context;
  48 };
  49
  50
  51 /*
  52   close the socket and shutdown a stream_connection
  53 */
  54 void stream_terminate_connection(struct stream_connection *srv_conn, const char *reason)
  55 {
  56         struct tevent_context *event_ctx = srv_conn->event.ctx;
  57         const struct model_ops *model_ops = srv_conn->model_ops;
  58         struct loadparm_context *lp_ctx = srv_conn->lp_ctx;
  59         void *process_context = srv_conn->process_context;
  60         TALLOC_CTX *frame = NULL;
  61
  62         if (!reason) reason = "unknown reason";
  63
  64         if (srv_conn->processing) {
  65                 DBG_NOTICE("Terminating connection deferred - '%s'\n", reason);
  66         } else {
  67                 DBG_NOTICE("Terminating connection - '%s'\n", reason);
  68         }
  69
  70         srv_conn->terminate = reason;
  71
  72         if (srv_conn->processing) {
  73                 /*
  74                  * if we're currently inside the stream_io_handler(),
  75                  * defer the termination to the end of stream_io_hendler()
  76                  *
  77                  * and we don't want to read or write to the connection...
  78                  */
  79                 tevent_fd_set_flags(srv_conn->event.fde, 0);
  80                 return;
  81         }
  82
  83         frame = talloc_stackframe();
  84
  85         reason = talloc_strdup(frame, reason);
  86         if (reason == NULL) {
  87                 reason = "OOM - unknown reason";
  88         }
  89
  90         talloc_free(srv_conn->event.fde);
  91         srv_conn->event.fde = NULL;
  92         imessaging_cleanup(srv_conn->msg_ctx);
  93         TALLOC_FREE(srv_conn);
  94         model_ops->terminate(event_ctx, lp_ctx, reason, process_context);
  95         TALLOC_FREE(frame);
  96 }
  97
  98 /**
  99   the select loop has indicated that a stream is ready for IO
 100 */
 101 static void stream_io_handler(struct stream_connection *conn, uint16_t flags)
 102 {
 103         conn->processing++;
 104         if (flags & TEVENT_FD_WRITE) {
 105                 conn->ops->send_handler(conn, flags);
 106         } else if (flags & TEVENT_FD_READ) {
 107                 conn->ops->recv_handler(conn, flags);
 108         }
 109         conn->processing--;
 110
 111         if (conn->terminate) {
 112                 stream_terminate_connection(conn, conn->terminate);
 113         }
 114 }
 115
 116 void stream_io_handler_fde(struct tevent_context *ev, struct tevent_fd *fde,
 117                                   uint16_t flags, void *private_data)
 118 {
 119         struct stream_connection *conn = talloc_get_type(private_data,
 120                                                          struct stream_connection);
 121         stream_io_handler(conn, flags);
 122 }
 123
 124 void stream_io_handler_callback(void *private_data, uint16_t flags)
 125 {
 126         struct stream_connection *conn = talloc_get_type(private_data,
 127                                                          struct stream_connection);
 128         stream_io_handler(conn, flags);
 129 }
 130
 131 /*
 132   this creates a stream_connection from an already existing connection,
 133   used for protocols, where a client connection needs to switched into
 134   a server connection
 135 */
 136 NTSTATUS stream_new_connection_merge(struct tevent_context *ev,
 137                                      struct loadparm_context *lp_ctx,
 138                                      const struct model_ops *model_ops,
 139                                      const struct stream_server_ops *stream_ops,
 140                                      struct imessaging_context *msg_ctx,
 141                                      void *private_data,
 142                                      struct stream_connection **_srv_conn,
 143                                      void *process_context)
 144 {
 145         struct stream_connection *srv_conn;
 146
 147         srv_conn = talloc_zero(ev, struct stream_connection);
 148         NT_STATUS_HAVE_NO_MEMORY(srv_conn);
 149
 150         srv_conn->private_data    = private_data;
 151         srv_conn->model_ops       = model_ops;
 152         srv_conn->socket          = NULL;
 153         srv_conn->server_id       = cluster_id(0, 0);
 154         srv_conn->ops             = stream_ops;
 155         srv_conn->msg_ctx         = msg_ctx;
 156         srv_conn->event.ctx       = ev;
 157         srv_conn->lp_ctx          = lp_ctx;
 158         srv_conn->event.fde       = NULL;
 159         srv_conn->process_context = process_context;
 160
 161         *_srv_conn = srv_conn;
 162         return NT_STATUS_OK;
 163 }
 164
 165 /*
 166   called when a new socket connection has been established. This is called in the process
 167   context of the new process (if appropriate)
 168 */
 169 static void stream_new_connection(struct tevent_context *ev,
 170                                   struct loadparm_context *lp_ctx,
 171                                   struct socket_context *sock,
 172                                   struct server_id server_id,
 173                                   void *private_data,
 174                                   void *process_context)
 175 {
 176         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 177         struct stream_connection *srv_conn;
 178
 179         srv_conn = talloc_zero(ev, struct stream_connection);
 180         if (!srv_conn) {
 181                 DBG_ERR("talloc(mem_ctx, struct stream_connection) failed\n");
 182                 return;
 183         }
 184
 185         talloc_steal(srv_conn, sock);
 186
 187         srv_conn->private_data    = stream_socket->private_data;
 188         srv_conn->model_ops       = stream_socket->model_ops;
 189         srv_conn->socket          = sock;
 190         srv_conn->server_id       = server_id;
 191         srv_conn->ops             = stream_socket->ops;
 192         srv_conn->event.ctx       = ev;
 193         srv_conn->lp_ctx          = lp_ctx;
 194         srv_conn->process_context = process_context;
 195
 196         if (!socket_check_access(sock, "smbd", lpcfg_hosts_allow(NULL, lpcfg_default_service(lp_ctx)), lpcfg_hosts_deny(NULL, lpcfg_default_service(lp_ctx)))) {
 197                 stream_terminate_connection(srv_conn, "denied by access rules");
 198                 return;
 199         }
 200
 201         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 202                                                 0, stream_io_handler_fde, srv_conn);
 203         if (!srv_conn->event.fde) {
 204                 stream_terminate_connection(srv_conn, "tevent_add_fd() failed");
 205                 return;
 206         }
 207
 208         /* setup to receive internal messages on this connection */
 209         srv_conn->msg_ctx = imessaging_init(srv_conn,
 210                                             lp_ctx,
 211                                             srv_conn->server_id, ev);
 212         if (!srv_conn->msg_ctx) {
 213                 stream_terminate_connection(srv_conn, "imessaging_init() failed");
 214                 return;
 215         }
 216
 217         srv_conn->remote_address = socket_get_remote_addr(srv_conn->socket, srv_conn);
 218         if (!srv_conn->remote_address) {
 219                 stream_terminate_connection(srv_conn, "socket_get_remote_addr() failed");
 220                 return;
 221         }
 222
 223         srv_conn->local_address = socket_get_local_addr(srv_conn->socket, srv_conn);
 224         if (!srv_conn->local_address) {
 225                 stream_terminate_connection(srv_conn, "socket_get_local_addr() failed");
 226                 return;
 227         }
 228
 229         {
 230                 TALLOC_CTX *tmp_ctx;
 231                 const char *title;
 232                 struct server_id_buf idbuf;
 233
 234                 tmp_ctx = talloc_new(srv_conn);
 235
 236                 title = talloc_asprintf(tmp_ctx, "conn[%s] c[%s] s[%s] server_id[%s]",
 237                                         stream_socket->ops->name,
 238                                         tsocket_address_string(srv_conn->remote_address, tmp_ctx),
 239                                         tsocket_address_string(srv_conn->local_address, tmp_ctx),
 240                                         server_id_str_buf(server_id, &idbuf));
 241                 if (title) {
 242                         stream_connection_set_title(srv_conn, title);
 243                 }
 244                 talloc_free(tmp_ctx);
 245         }
 246
 247         /* we're now ready to start receiving events on this stream */
 248         TEVENT_FD_READABLE(srv_conn->event.fde);
 249
 250         /* call the server specific accept code */
 251         stream_socket->ops->accept_connection(srv_conn);
 252 }
 253
 254
 255 /*
 256   called when someone opens a connection to one of our listening ports
 257 */
 258 static void stream_accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
 259                                   uint16_t flags, void *private_data)
 260 {
 261         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 262
 263         /* ask the process model to create us a process for this new
 264            connection.  When done, it calls stream_new_connection()
 265            with the newly created socket */
 266         stream_socket->model_ops->accept_connection(
 267                 ev,
 268                 stream_socket->lp_ctx,
 269                 stream_socket->sock,
 270                 stream_new_connection,
 271                 stream_socket,
 272                 stream_socket->process_context);
 273 }
 274
 275 /*
 276   setup a listen stream socket
 277   if you pass *port == 0, then a port > 1024 is used
 278
 279   FIXME: This function is TCP/IP specific - uses an int rather than
 280          a string for the port. Should leave allocating a port nr
 281          to the socket implementation - JRV20070903
 282  */
 283 NTSTATUS stream_setup_socket(TALLOC_CTX *mem_ctx,
 284                              struct tevent_context *event_context,
 285                              struct loadparm_context *lp_ctx,
 286                              const struct model_ops *model_ops,
 287                              const struct stream_server_ops *stream_ops,
 288                              const char *family,
 289                              const char *sock_addr,
 290                              uint16_t *port,
 291                              const char *socket_options,
 292                              void *private_data,
 293                              void *process_context)
 294 {
 295         NTSTATUS status;
 296         struct stream_socket *stream_socket;
 297         struct socket_address *socket_address;
 298         struct tevent_fd *fde;
 299         int i;
 300         struct sockaddr_storage ss;
 301
 302         stream_socket = talloc_zero(mem_ctx, struct stream_socket);
 303         NT_STATUS_HAVE_NO_MEMORY(stream_socket);
 304
 305         if (strcmp(family, "ip") == 0) {
 306                 /* we will get the real family from the address itself */
 307                 if (!interpret_string_addr(&ss, sock_addr, 0)) {
 308                         talloc_free(stream_socket);
 309                         return NT_STATUS_INVALID_ADDRESS;
 310                 }
 311
 312                 socket_address = socket_address_from_sockaddr_storage(stream_socket, &ss, port?*port:0);
 313                 if (socket_address == NULL) {
 314                         TALLOC_FREE(stream_socket);
 315                         return NT_STATUS_NO_MEMORY;
 316                 }
 317
 318                 status = socket_create(socket_address->family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 319                 NT_STATUS_NOT_OK_RETURN(status);
 320         } else {
 321                 status = socket_create(family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 322                 NT_STATUS_NOT_OK_RETURN(status);
 323
 324                 /* this is for non-IP sockets, eg. unix domain sockets */
 325                 socket_address = socket_address_from_strings(stream_socket,
 326                                                              stream_socket->sock->backend_name,
 327                                                              sock_addr, port?*port:0);
 328                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 329         }
 330
 331
 332         talloc_steal(stream_socket, stream_socket->sock);
 333
 334         stream_socket->lp_ctx = talloc_reference(stream_socket, lp_ctx);
 335
 336         /* ready to listen */
 337         status = socket_set_option(stream_socket->sock, "SO_KEEPALIVE", NULL);
 338         NT_STATUS_NOT_OK_RETURN(status);
 339
 340         if (socket_options != NULL) {
 341                 status = socket_set_option(stream_socket->sock, socket_options, NULL);
 342                 NT_STATUS_NOT_OK_RETURN(status);
 343         }
 344
 345         /* TODO: set socket ACL's (host allow etc) here when they're
 346          * implemented */
 347
 348         /* Some sockets don't have a port, or are just described from
 349          * the string.  We are indicating this by having port == NULL */
 350         if (!port) {
 351                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 352         } else if (*port == 0) {
 353                 for (i = lpcfg_rpc_low_port(lp_ctx);
 354                      i <= lpcfg_rpc_high_port(lp_ctx);
 355                      i++) {
 356                         socket_address->port = i;
 357                         status = socket_listen(stream_socket->sock, socket_address,
 358                                                SERVER_LISTEN_BACKLOG, 0);
 359                         if (NT_STATUS_IS_OK(status)) {
 360                                 *port = i;
 361                                 break;
 362                         }
 363                 }
 364         } else {
 365                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 366         }
 367
 368         if (!NT_STATUS_IS_OK(status)) {
 369                 DBG_ERR("Failed to listen on %s:%u - %s\n",
 370                          sock_addr, port ? (unsigned int)(*port) : 0,
 371                          nt_errstr(status));
 372                 talloc_free(stream_socket);
 373                 return status;
 374         }
 375
 376         /* Add the FD from the newly created socket into the event
 377          * subsystem.  it will call the accept handler whenever we get
 378          * new connections */
 379
 380         fde = tevent_add_fd(event_context, stream_socket->sock,
 381                             socket_get_fd(stream_socket->sock),
 382                             TEVENT_FD_READ,
 383                             stream_accept_handler, stream_socket);
 384         if (!fde) {
 385                 DBG_ERR("Failed to setup fd event\n");
 386                 talloc_free(stream_socket);
 387                 return NT_STATUS_NO_MEMORY;
 388         }
 389
 390         /* we let events system to the close on the socket. This avoids
 391          * nasty interactions with waiting for talloc to close the socket. */
 392         tevent_fd_set_close_fn(fde, socket_tevent_fd_close_fn);
 393         socket_set_flags(stream_socket->sock, SOCKET_FLAG_NOCLOSE);
 394
 395         stream_socket->private_data     = talloc_reference(stream_socket, private_data);
 396         stream_socket->ops              = stream_ops;
 397         stream_socket->event_ctx        = event_context;
 398         stream_socket->model_ops        = model_ops;
 399         stream_socket->process_context  = process_context;
 400
 401         return NT_STATUS_OK;
 402 }
 403
 404
 405 /*
 406   setup a connection title
 407 */
 408 void stream_connection_set_title(struct stream_connection *conn, const char *title)
 409 {
 410         conn->model_ops->set_title(conn->event.ctx, title);
 411 }