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