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_connection(
  95             event_ctx, lp_ctx, reason, process_context);
  96         TALLOC_FREE(frame);
  97 }
  98
  99 /**
 100   the select loop has indicated that a stream is ready for IO
 101 */
 102 static void stream_io_handler(struct stream_connection *conn, uint16_t flags)
 103 {
 104         conn->processing++;
 105         if (flags & TEVENT_FD_WRITE) {
 106                 conn->ops->send_handler(conn, flags);
 107         } else if (flags & TEVENT_FD_READ) {
 108                 conn->ops->recv_handler(conn, flags);
 109         }
 110         conn->processing--;
 111
 112         if (conn->terminate) {
 113                 stream_terminate_connection(conn, conn->terminate);
 114         }
 115 }
 116
 117 void stream_io_handler_fde(struct tevent_context *ev, struct tevent_fd *fde,
 118                                   uint16_t flags, void *private_data)
 119 {
 120         struct stream_connection *conn = talloc_get_type(private_data,
 121                                                          struct stream_connection);
 122         stream_io_handler(conn, flags);
 123 }
 124
 125 void stream_io_handler_callback(void *private_data, uint16_t flags)
 126 {
 127         struct stream_connection *conn = talloc_get_type(private_data,
 128                                                          struct stream_connection);
 129         stream_io_handler(conn, flags);
 130 }
 131
 132 /*
 133   this creates a stream_connection from an already existing connection,
 134   used for protocols, where a client connection needs to switched into
 135   a server connection
 136 */
 137 NTSTATUS stream_new_connection_merge(struct tevent_context *ev,
 138                                      struct loadparm_context *lp_ctx,
 139                                      const struct model_ops *model_ops,
 140                                      const struct stream_server_ops *stream_ops,
 141                                      struct imessaging_context *msg_ctx,
 142                                      void *private_data,
 143                                      struct stream_connection **_srv_conn,
 144                                      void *process_context)
 145 {
 146         struct stream_connection *srv_conn;
 147
 148         srv_conn = talloc_zero(ev, struct stream_connection);
 149         NT_STATUS_HAVE_NO_MEMORY(srv_conn);
 150
 151         srv_conn->private_data    = private_data;
 152         srv_conn->model_ops       = model_ops;
 153         srv_conn->socket          = NULL;
 154         srv_conn->server_id       = cluster_id(0, 0);
 155         srv_conn->ops             = stream_ops;
 156         srv_conn->msg_ctx         = msg_ctx;
 157         srv_conn->event.ctx       = ev;
 158         srv_conn->lp_ctx          = lp_ctx;
 159         srv_conn->event.fde       = NULL;
 160         srv_conn->process_context = process_context;
 161
 162         *_srv_conn = srv_conn;
 163         return NT_STATUS_OK;
 164 }
 165
 166 /*
 167   called when a new socket connection has been established. This is called in the process
 168   context of the new process (if appropriate)
 169 */
 170 static void stream_new_connection(struct tevent_context *ev,
 171                                   struct loadparm_context *lp_ctx,
 172                                   struct socket_context *sock,
 173                                   struct server_id server_id,
 174                                   void *private_data,
 175                                   void *process_context)
 176 {
 177         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 178         struct stream_connection *srv_conn;
 179
 180         srv_conn = talloc_zero(ev, struct stream_connection);
 181         if (!srv_conn) {
 182                 DBG_ERR("talloc(mem_ctx, struct stream_connection) failed\n");
 183                 return;
 184         }
 185
 186         talloc_steal(srv_conn, sock);
 187
 188         srv_conn->private_data    = stream_socket->private_data;
 189         srv_conn->model_ops       = stream_socket->model_ops;
 190         srv_conn->socket          = sock;
 191         srv_conn->server_id       = server_id;
 192         srv_conn->ops             = stream_socket->ops;
 193         srv_conn->event.ctx       = ev;
 194         srv_conn->lp_ctx          = lp_ctx;
 195         srv_conn->process_context = process_context;
 196
 197         if (!socket_check_access(sock, "smbd", lpcfg_hosts_allow(NULL, lpcfg_default_service(lp_ctx)), lpcfg_hosts_deny(NULL, lpcfg_default_service(lp_ctx)))) {
 198                 stream_terminate_connection(srv_conn, "denied by access rules");
 199                 return;
 200         }
 201
 202         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 203                                                 0, stream_io_handler_fde, srv_conn);
 204         if (!srv_conn->event.fde) {
 205                 stream_terminate_connection(srv_conn, "tevent_add_fd() failed");
 206                 return;
 207         }
 208
 209         /* setup to receive internal messages on this connection */
 210         srv_conn->msg_ctx = imessaging_init(srv_conn,
 211                                             lp_ctx,
 212                                             srv_conn->server_id, ev);
 213         if (!srv_conn->msg_ctx) {
 214                 stream_terminate_connection(srv_conn, "imessaging_init() failed");
 215                 return;
 216         }
 217
 218         srv_conn->remote_address = socket_get_remote_addr(srv_conn->socket, srv_conn);
 219         if (!srv_conn->remote_address) {
 220                 stream_terminate_connection(srv_conn, "socket_get_remote_addr() failed");
 221                 return;
 222         }
 223
 224         srv_conn->local_address = socket_get_local_addr(srv_conn->socket, srv_conn);
 225         if (!srv_conn->local_address) {
 226                 stream_terminate_connection(srv_conn, "socket_get_local_addr() failed");
 227                 return;
 228         }
 229
 230         {
 231                 TALLOC_CTX *tmp_ctx;
 232                 const char *title;
 233                 struct server_id_buf idbuf;
 234
 235                 tmp_ctx = talloc_new(srv_conn);
 236
 237                 title = talloc_asprintf(tmp_ctx, "conn[%s] c[%s] s[%s] server_id[%s]",
 238                                         stream_socket->ops->name,
 239                                         tsocket_address_string(srv_conn->remote_address, tmp_ctx),
 240                                         tsocket_address_string(srv_conn->local_address, tmp_ctx),
 241                                         server_id_str_buf(server_id, &idbuf));
 242                 if (title) {
 243                         stream_connection_set_title(srv_conn, title);
 244                 }
 245                 talloc_free(tmp_ctx);
 246         }
 247
 248         /* we're now ready to start receiving events on this stream */
 249         TEVENT_FD_READABLE(srv_conn->event.fde);
 250
 251         /* call the server specific accept code */
 252         stream_socket->ops->accept_connection(srv_conn);
 253 }
 254
 255
 256 /*
 257   called when someone opens a connection to one of our listening ports
 258 */
 259 static void stream_accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
 260                                   uint16_t flags, void *private_data)
 261 {
 262         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 263
 264         /* ask the process model to create us a process for this new
 265            connection.  When done, it calls stream_new_connection()
 266            with the newly created socket */
 267         stream_socket->model_ops->accept_connection(
 268                 ev,
 269                 stream_socket->lp_ctx,
 270                 stream_socket->sock,
 271                 stream_new_connection,
 272                 stream_socket,
 273                 stream_socket->process_context);
 274 }
 275
 276 /*
 277   setup a listen stream socket
 278   if you pass *port == 0, then a port > 1024 is used
 279
 280   FIXME: This function is TCP/IP specific - uses an int rather than
 281          a string for the port. Should leave allocating a port nr
 282          to the socket implementation - JRV20070903
 283  */
 284 NTSTATUS stream_setup_socket(TALLOC_CTX *mem_ctx,
 285                              struct tevent_context *event_context,
 286                              struct loadparm_context *lp_ctx,
 287                              const struct model_ops *model_ops,
 288                              const struct stream_server_ops *stream_ops,
 289                              const char *family,
 290                              const char *sock_addr,
 291                              uint16_t *port,
 292                              const char *socket_options,
 293                              void *private_data,
 294                              void *process_context)
 295 {
 296         NTSTATUS status;
 297         struct stream_socket *stream_socket;
 298         struct socket_address *socket_address;
 299         struct tevent_fd *fde;
 300         int i;
 301         struct sockaddr_storage ss;
 302
 303         stream_socket = talloc_zero(mem_ctx, struct stream_socket);
 304         NT_STATUS_HAVE_NO_MEMORY(stream_socket);
 305
 306         if (strcmp(family, "ip") == 0) {
 307                 /* we will get the real family from the address itself */
 308                 if (!interpret_string_addr(&ss, sock_addr, 0)) {
 309                         talloc_free(stream_socket);
 310                         return NT_STATUS_INVALID_ADDRESS;
 311                 }
 312
 313                 socket_address = socket_address_from_sockaddr_storage(stream_socket, &ss, port?*port:0);
 314                 if (socket_address == NULL) {
 315                         TALLOC_FREE(stream_socket);
 316                         return NT_STATUS_NO_MEMORY;
 317                 }
 318
 319                 status = socket_create(stream_socket, socket_address->family,
 320                                        SOCKET_TYPE_STREAM,
 321                                        &stream_socket->sock, 0);
 322                 NT_STATUS_NOT_OK_RETURN(status);
 323         } else {
 324                 status = socket_create(stream_socket, family,
 325                                        SOCKET_TYPE_STREAM,
 326                                        &stream_socket->sock, 0);
 327                 NT_STATUS_NOT_OK_RETURN(status);
 328
 329                 /* this is for non-IP sockets, eg. unix domain sockets */
 330                 socket_address = socket_address_from_strings(stream_socket,
 331                                                              stream_socket->sock->backend_name,
 332                                                              sock_addr, port?*port:0);
 333                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 334         }
 335
 336
 337         stream_socket->lp_ctx = talloc_reference(stream_socket, lp_ctx);
 338
 339         /* ready to listen */
 340         status = socket_set_option(stream_socket->sock, "SO_KEEPALIVE", NULL);
 341         NT_STATUS_NOT_OK_RETURN(status);
 342
 343         if (socket_options != NULL) {
 344                 status = socket_set_option(stream_socket->sock, socket_options, NULL);
 345                 NT_STATUS_NOT_OK_RETURN(status);
 346         }
 347
 348         /* TODO: set socket ACL's (host allow etc) here when they're
 349          * implemented */
 350
 351         /* Some sockets don't have a port, or are just described from
 352          * the string.  We are indicating this by having port == NULL */
 353         if (!port) {
 354                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 355         } else if (*port == 0) {
 356                 for (i = lpcfg_rpc_low_port(lp_ctx);
 357                      i <= lpcfg_rpc_high_port(lp_ctx);
 358                      i++) {
 359                         socket_address->port = i;
 360                         status = socket_listen(stream_socket->sock, socket_address,
 361                                                SERVER_LISTEN_BACKLOG, 0);
 362                         if (NT_STATUS_IS_OK(status)) {
 363                                 *port = i;
 364                                 break;
 365                         }
 366                 }
 367         } else {
 368                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 369         }
 370
 371         if (!NT_STATUS_IS_OK(status)) {
 372                 DBG_ERR("Failed to listen on %s:%u - %s\n",
 373                          sock_addr, port ? (unsigned int)(*port) : 0,
 374                          nt_errstr(status));
 375                 talloc_free(stream_socket);
 376                 return status;
 377         }
 378
 379         /* Add the FD from the newly created socket into the event
 380          * subsystem.  it will call the accept handler whenever we get
 381          * new connections */
 382
 383         fde = tevent_add_fd(event_context, stream_socket->sock,
 384                             socket_get_fd(stream_socket->sock),
 385                             TEVENT_FD_READ,
 386                             stream_accept_handler, stream_socket);
 387         if (!fde) {
 388                 DBG_ERR("Failed to setup fd event\n");
 389                 talloc_free(stream_socket);
 390                 return NT_STATUS_NO_MEMORY;
 391         }
 392
 393         /* we let events system to the close on the socket. This avoids
 394          * nasty interactions with waiting for talloc to close the socket. */
 395         tevent_fd_set_close_fn(fde, socket_tevent_fd_close_fn);
 396         socket_set_flags(stream_socket->sock, SOCKET_FLAG_NOCLOSE);
 397
 398         stream_socket->private_data     = talloc_reference(stream_socket, private_data);
 399         stream_socket->ops              = stream_ops;
 400         stream_socket->event_ctx        = event_context;
 401         stream_socket->model_ops        = model_ops;
 402         stream_socket->process_context  = process_context;
 403
 404         return NT_STATUS_OK;
 405 }
 406
 407
 408 /*
 409   setup a connection title
 410 */
 411 void stream_connection_set_title(struct stream_connection *conn, const char *title)
 412 {
 413         conn->model_ops->set_title(conn->event.ctx, title);
 414 }