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/messaging/irpc.h"
  27 #include "cluster/cluster.h"
  28 #include "param/param.h"
  29 #include "../lib/tsocket/tsocket.h"
  30
  31 /* the range of ports to try for dcerpc over tcp endpoints */
  32 #define SERVER_TCP_LOW_PORT  1024
  33 #define SERVER_TCP_HIGH_PORT 1300
  34
  35 /* size of listen() backlog in smbd */
  36 #define SERVER_LISTEN_BACKLOG 10
  37
  38
  39 /*
  40   private structure for a single listening stream socket
  41 */
  42 struct stream_socket {
  43         const struct stream_server_ops *ops;
  44         struct loadparm_context *lp_ctx;
  45         struct tevent_context *event_ctx;
  46         const struct model_ops *model_ops;
  47         struct socket_context *sock;
  48         void *private_data;
  49 };
  50
  51
  52 /*
  53   close the socket and shutdown a stream_connection
  54 */
  55 void stream_terminate_connection(struct stream_connection *srv_conn, const char *reason)
  56 {
  57         struct tevent_context *event_ctx = srv_conn->event.ctx;
  58         const struct model_ops *model_ops = srv_conn->model_ops;
  59
  60         if (!reason) reason = "unknown reason";
  61
  62         DEBUG(3,("Terminating connection - '%s'\n", reason));
  63
  64         srv_conn->terminate = reason;
  65
  66         if (srv_conn->processing) {
  67                 /*
  68                  * if we're currently inside the stream_io_handler(),
  69                  * defer the termination to the end of stream_io_hendler()
  70                  *
  71                  * and we don't want to read or write to the connection...
  72                  */
  73                 tevent_fd_set_flags(srv_conn->event.fde, 0);
  74                 return;
  75         }
  76
  77         talloc_free(srv_conn->event.fde);
  78         srv_conn->event.fde = NULL;
  79         model_ops->terminate(event_ctx, srv_conn->lp_ctx, reason);
  80         talloc_free(srv_conn);
  81 }
  82
  83 /**
  84   the select loop has indicated that a stream is ready for IO
  85 */
  86 static void stream_io_handler(struct stream_connection *conn, uint16_t flags)
  87 {
  88         conn->processing++;
  89         if (flags & TEVENT_FD_WRITE) {
  90                 conn->ops->send_handler(conn, flags);
  91         } else if (flags & TEVENT_FD_READ) {
  92                 conn->ops->recv_handler(conn, flags);
  93         }
  94         conn->processing--;
  95
  96         if (conn->terminate) {
  97                 stream_terminate_connection(conn, conn->terminate);
  98         }
  99 }
 100
 101 void stream_io_handler_fde(struct tevent_context *ev, struct tevent_fd *fde,
 102                                   uint16_t flags, void *private_data)
 103 {
 104         struct stream_connection *conn = talloc_get_type(private_data,
 105                                                          struct stream_connection);
 106         stream_io_handler(conn, flags);
 107 }
 108
 109 void stream_io_handler_callback(void *private_data, uint16_t flags)
 110 {
 111         struct stream_connection *conn = talloc_get_type(private_data,
 112                                                          struct stream_connection);
 113         stream_io_handler(conn, flags);
 114 }
 115
 116 /*
 117   this creates a stream_connection from an already existing connection,
 118   used for protocols, where a client connection needs to switched into
 119   a server connection
 120 */
 121 NTSTATUS stream_new_connection_merge(struct tevent_context *ev,
 122                                      struct loadparm_context *lp_ctx,
 123                                      const struct model_ops *model_ops,
 124                                      const struct stream_server_ops *stream_ops,
 125                                      struct messaging_context *msg_ctx,
 126                                      void *private_data,
 127                                      struct stream_connection **_srv_conn)
 128 {
 129         struct stream_connection *srv_conn;
 130
 131         srv_conn = talloc_zero(ev, struct stream_connection);
 132         NT_STATUS_HAVE_NO_MEMORY(srv_conn);
 133
 134         srv_conn->private_data  = private_data;
 135         srv_conn->model_ops     = model_ops;
 136         srv_conn->socket        = NULL;
 137         srv_conn->server_id     = cluster_id(0, 0);
 138         srv_conn->ops           = stream_ops;
 139         srv_conn->msg_ctx       = msg_ctx;
 140         srv_conn->event.ctx     = ev;
 141         srv_conn->lp_ctx        = lp_ctx;
 142         srv_conn->event.fde     = NULL;
 143
 144         *_srv_conn = srv_conn;
 145         return NT_STATUS_OK;
 146 }
 147
 148 /*
 149   called when a new socket connection has been established. This is called in the process
 150   context of the new process (if appropriate)
 151 */
 152 static void stream_new_connection(struct tevent_context *ev,
 153                                   struct loadparm_context *lp_ctx,
 154                                   struct socket_context *sock,
 155                                   struct server_id server_id, void *private_data)
 156 {
 157         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 158         struct stream_connection *srv_conn;
 159
 160         srv_conn = talloc_zero(ev, struct stream_connection);
 161         if (!srv_conn) {
 162                 DEBUG(0,("talloc(mem_ctx, struct stream_connection) failed\n"));
 163                 return;
 164         }
 165
 166         talloc_steal(srv_conn, sock);
 167
 168         srv_conn->private_data  = stream_socket->private_data;
 169         srv_conn->model_ops     = stream_socket->model_ops;
 170         srv_conn->socket        = sock;
 171         srv_conn->server_id     = server_id;
 172         srv_conn->ops           = stream_socket->ops;
 173         srv_conn->event.ctx     = ev;
 174         srv_conn->lp_ctx        = lp_ctx;
 175
 176         if (!socket_check_access(sock, "smbd", lpcfg_hostsallow(NULL, lpcfg_default_service(lp_ctx)), lpcfg_hostsdeny(NULL, lpcfg_default_service(lp_ctx)))) {
 177                 stream_terminate_connection(srv_conn, "denied by access rules");
 178                 return;
 179         }
 180
 181         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 182                                                 0, stream_io_handler_fde, srv_conn);
 183         if (!srv_conn->event.fde) {
 184                 stream_terminate_connection(srv_conn, "tevent_add_fd() failed");
 185                 return;
 186         }
 187
 188         /* setup to receive internal messages on this connection */
 189         srv_conn->msg_ctx = messaging_init(srv_conn,
 190                                            lpcfg_messaging_path(srv_conn, lp_ctx),
 191                                            srv_conn->server_id, ev);
 192         if (!srv_conn->msg_ctx) {
 193                 stream_terminate_connection(srv_conn, "messaging_init() failed");
 194                 return;
 195         }
 196
 197         srv_conn->remote_address = socket_get_remote_addr(srv_conn->socket, srv_conn);
 198         if (!srv_conn->remote_address) {
 199                 stream_terminate_connection(srv_conn, "socket_get_remote_addr() failed");
 200                 return;
 201         }
 202
 203         srv_conn->local_address = socket_get_local_addr(srv_conn->socket, srv_conn);
 204         if (!srv_conn->local_address) {
 205                 stream_terminate_connection(srv_conn, "socket_get_local_addr() failed");
 206                 return;
 207         }
 208
 209         {
 210                 TALLOC_CTX *tmp_ctx;
 211                 const char *title;
 212
 213                 tmp_ctx = talloc_new(srv_conn);
 214
 215                 title = talloc_asprintf(tmp_ctx, "conn[%s] c[%s] s[%s] server_id[%s]",
 216                                         stream_socket->ops->name,
 217                                         tsocket_address_string(srv_conn->remote_address, tmp_ctx),
 218                                         tsocket_address_string(srv_conn->local_address, tmp_ctx),
 219                                         cluster_id_string(tmp_ctx, server_id));
 220                 if (title) {
 221                         stream_connection_set_title(srv_conn, title);
 222                 }
 223                 talloc_free(tmp_ctx);
 224         }
 225
 226         /* we're now ready to start receiving events on this stream */
 227         TEVENT_FD_READABLE(srv_conn->event.fde);
 228
 229         /* call the server specific accept code */
 230         stream_socket->ops->accept_connection(srv_conn);
 231 }
 232
 233
 234 /*
 235   called when someone opens a connection to one of our listening ports
 236 */
 237 static void stream_accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
 238                                   uint16_t flags, void *private_data)
 239 {
 240         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 241
 242         /* ask the process model to create us a process for this new
 243            connection.  When done, it calls stream_new_connection()
 244            with the newly created socket */
 245         stream_socket->model_ops->accept_connection(ev, stream_socket->lp_ctx,
 246                                                     stream_socket->sock,
 247                                                     stream_new_connection, stream_socket);
 248 }
 249
 250 /*
 251   setup a listen stream socket
 252   if you pass *port == 0, then a port > 1024 is used
 253
 254   FIXME: This function is TCP/IP specific - uses an int rather than
 255          a string for the port. Should leave allocating a port nr
 256          to the socket implementation - JRV20070903
 257  */
 258 NTSTATUS stream_setup_socket(TALLOC_CTX *mem_ctx,
 259                              struct tevent_context *event_context,
 260                              struct loadparm_context *lp_ctx,
 261                              const struct model_ops *model_ops,
 262                              const struct stream_server_ops *stream_ops,
 263                              const char *family,
 264                              const char *sock_addr,
 265                              uint16_t *port,
 266                              const char *socket_options,
 267                              void *private_data)
 268 {
 269         NTSTATUS status;
 270         struct stream_socket *stream_socket;
 271         struct socket_address *socket_address;
 272         struct tevent_fd *fde;
 273         int i;
 274
 275         stream_socket = talloc_zero(mem_ctx, struct stream_socket);
 276         NT_STATUS_HAVE_NO_MEMORY(stream_socket);
 277
 278         status = socket_create(family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 279         NT_STATUS_NOT_OK_RETURN(status);
 280
 281         talloc_steal(stream_socket, stream_socket->sock);
 282
 283         stream_socket->lp_ctx = talloc_reference(stream_socket, lp_ctx);
 284
 285         /* ready to listen */
 286         status = socket_set_option(stream_socket->sock, "SO_KEEPALIVE", NULL);
 287         NT_STATUS_NOT_OK_RETURN(status);
 288
 289         if (socket_options != NULL) {
 290                 status = socket_set_option(stream_socket->sock, socket_options, NULL);
 291                 NT_STATUS_NOT_OK_RETURN(status);
 292         }
 293
 294         /* TODO: set socket ACL's (host allow etc) here when they're
 295          * implemented */
 296
 297         /* Some sockets don't have a port, or are just described from
 298          * the string.  We are indicating this by having port == NULL */
 299         if (!port) {
 300                 socket_address = socket_address_from_strings(stream_socket,
 301                                                              stream_socket->sock->backend_name,
 302                                                              sock_addr, 0);
 303                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 304                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 305                 talloc_free(socket_address);
 306
 307         } else if (*port == 0) {
 308                 for (i=SERVER_TCP_LOW_PORT;i<= SERVER_TCP_HIGH_PORT;i++) {
 309                         socket_address = socket_address_from_strings(stream_socket,
 310                                                                      stream_socket->sock->backend_name,
 311                                                                      sock_addr, i);
 312                         NT_STATUS_HAVE_NO_MEMORY(socket_address);
 313                         status = socket_listen(stream_socket->sock, socket_address,
 314                                                SERVER_LISTEN_BACKLOG, 0);
 315                         talloc_free(socket_address);
 316                         if (NT_STATUS_IS_OK(status)) {
 317                                 *port = i;
 318                                 break;
 319                         }
 320                 }
 321         } else {
 322                 socket_address = socket_address_from_strings(stream_socket,
 323                                                              stream_socket->sock->backend_name,
 324                                                              sock_addr, *port);
 325                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 326                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 327                 talloc_free(socket_address);
 328         }
 329
 330         if (!NT_STATUS_IS_OK(status)) {
 331                 DEBUG(0,("Failed to listen on %s:%u - %s\n",
 332                          sock_addr, port ? (unsigned int)(*port) : 0,
 333                          nt_errstr(status)));
 334                 talloc_free(stream_socket);
 335                 return status;
 336         }
 337
 338         /* Add the FD from the newly created socket into the event
 339          * subsystem.  it will call the accept handler whenever we get
 340          * new connections */
 341
 342         fde = tevent_add_fd(event_context, stream_socket->sock,
 343                             socket_get_fd(stream_socket->sock),
 344                             TEVENT_FD_READ,
 345                             stream_accept_handler, stream_socket);
 346         if (!fde) {
 347                 DEBUG(0,("Failed to setup fd event\n"));
 348                 talloc_free(stream_socket);
 349                 return NT_STATUS_NO_MEMORY;
 350         }
 351
 352         /* we let events system to the close on the socket. This avoids
 353          * nasty interactions with waiting for talloc to close the socket. */
 354         tevent_fd_set_close_fn(fde, socket_tevent_fd_close_fn);
 355         socket_set_flags(stream_socket->sock, SOCKET_FLAG_NOCLOSE);
 356
 357         stream_socket->private_data     = talloc_reference(stream_socket, private_data);
 358         stream_socket->ops              = stream_ops;
 359         stream_socket->event_ctx        = event_context;
 360         stream_socket->model_ops        = model_ops;
 361
 362         return NT_STATUS_OK;
 363 }
 364
 365 /*
 366   setup a connection title
 367 */
 368 void stream_connection_set_title(struct stream_connection *conn, const char *title)
 369 {
 370         conn->model_ops->set_title(conn->event.ctx, title);
 371 }