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 #include "lib/util/util_net.h"
  31
  32 /* the range of ports to try for dcerpc over tcp endpoints */
  33 #define SERVER_TCP_LOW_PORT  1024
  34 #define SERVER_TCP_HIGH_PORT 1300
  35
  36 /* size of listen() backlog in smbd */
  37 #define SERVER_LISTEN_BACKLOG 10
  38
  39
  40 /*
  41   private structure for a single listening stream socket
  42 */
  43 struct stream_socket {
  44         const struct stream_server_ops *ops;
  45         struct loadparm_context *lp_ctx;
  46         struct tevent_context *event_ctx;
  47         const struct model_ops *model_ops;
  48         struct socket_context *sock;
  49         void *private_data;
  50 };
  51
  52
  53 /*
  54   close the socket and shutdown a stream_connection
  55 */
  56 void stream_terminate_connection(struct stream_connection *srv_conn, const char *reason)
  57 {
  58         struct tevent_context *event_ctx = srv_conn->event.ctx;
  59         const struct model_ops *model_ops = srv_conn->model_ops;
  60
  61         if (!reason) reason = "unknown reason";
  62
  63         if (srv_conn->processing) {
  64                 DEBUG(3,("Terminating connection deferred - '%s'\n", reason));
  65         } else {
  66                 DEBUG(3,("Terminating connection - '%s'\n", reason));
  67         }
  68
  69         srv_conn->terminate = reason;
  70
  71         if (srv_conn->processing) {
  72                 /*
  73                  * if we're currently inside the stream_io_handler(),
  74                  * defer the termination to the end of stream_io_hendler()
  75                  *
  76                  * and we don't want to read or write to the connection...
  77                  */
  78                 tevent_fd_set_flags(srv_conn->event.fde, 0);
  79                 return;
  80         }
  81
  82         talloc_free(srv_conn->event.fde);
  83         srv_conn->event.fde = NULL;
  84         imessaging_cleanup(srv_conn->msg_ctx);
  85         model_ops->terminate(event_ctx, srv_conn->lp_ctx, reason);
  86         talloc_free(srv_conn);
  87 }
  88
  89 /**
  90   the select loop has indicated that a stream is ready for IO
  91 */
  92 static void stream_io_handler(struct stream_connection *conn, uint16_t flags)
  93 {
  94         conn->processing++;
  95         if (flags & TEVENT_FD_WRITE) {
  96                 conn->ops->send_handler(conn, flags);
  97         } else if (flags & TEVENT_FD_READ) {
  98                 conn->ops->recv_handler(conn, flags);
  99         }
 100         conn->processing--;
 101
 102         if (conn->terminate) {
 103                 stream_terminate_connection(conn, conn->terminate);
 104         }
 105 }
 106
 107 void stream_io_handler_fde(struct tevent_context *ev, struct tevent_fd *fde,
 108                                   uint16_t flags, void *private_data)
 109 {
 110         struct stream_connection *conn = talloc_get_type(private_data,
 111                                                          struct stream_connection);
 112         stream_io_handler(conn, flags);
 113 }
 114
 115 void stream_io_handler_callback(void *private_data, uint16_t flags)
 116 {
 117         struct stream_connection *conn = talloc_get_type(private_data,
 118                                                          struct stream_connection);
 119         stream_io_handler(conn, flags);
 120 }
 121
 122 /*
 123   this creates a stream_connection from an already existing connection,
 124   used for protocols, where a client connection needs to switched into
 125   a server connection
 126 */
 127 NTSTATUS stream_new_connection_merge(struct tevent_context *ev,
 128                                      struct loadparm_context *lp_ctx,
 129                                      const struct model_ops *model_ops,
 130                                      const struct stream_server_ops *stream_ops,
 131                                      struct imessaging_context *msg_ctx,
 132                                      void *private_data,
 133                                      struct stream_connection **_srv_conn)
 134 {
 135         struct stream_connection *srv_conn;
 136
 137         srv_conn = talloc_zero(ev, struct stream_connection);
 138         NT_STATUS_HAVE_NO_MEMORY(srv_conn);
 139
 140         srv_conn->private_data  = private_data;
 141         srv_conn->model_ops     = model_ops;
 142         srv_conn->socket        = NULL;
 143         srv_conn->server_id     = cluster_id(0, 0);
 144         srv_conn->ops           = stream_ops;
 145         srv_conn->msg_ctx       = msg_ctx;
 146         srv_conn->event.ctx     = ev;
 147         srv_conn->lp_ctx        = lp_ctx;
 148         srv_conn->event.fde     = NULL;
 149
 150         *_srv_conn = srv_conn;
 151         return NT_STATUS_OK;
 152 }
 153
 154 /*
 155   called when a new socket connection has been established. This is called in the process
 156   context of the new process (if appropriate)
 157 */
 158 static void stream_new_connection(struct tevent_context *ev,
 159                                   struct loadparm_context *lp_ctx,
 160                                   struct socket_context *sock,
 161                                   struct server_id server_id, void *private_data)
 162 {
 163         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 164         struct stream_connection *srv_conn;
 165
 166         srv_conn = talloc_zero(ev, struct stream_connection);
 167         if (!srv_conn) {
 168                 DEBUG(0,("talloc(mem_ctx, struct stream_connection) failed\n"));
 169                 return;
 170         }
 171
 172         talloc_steal(srv_conn, sock);
 173
 174         srv_conn->private_data  = stream_socket->private_data;
 175         srv_conn->model_ops     = stream_socket->model_ops;
 176         srv_conn->socket        = sock;
 177         srv_conn->server_id     = server_id;
 178         srv_conn->ops           = stream_socket->ops;
 179         srv_conn->event.ctx     = ev;
 180         srv_conn->lp_ctx        = lp_ctx;
 181
 182         if (!socket_check_access(sock, "smbd", lpcfg_hostsallow(NULL, lpcfg_default_service(lp_ctx)), lpcfg_hostsdeny(NULL, lpcfg_default_service(lp_ctx)))) {
 183                 stream_terminate_connection(srv_conn, "denied by access rules");
 184                 return;
 185         }
 186
 187         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 188                                                 0, stream_io_handler_fde, srv_conn);
 189         if (!srv_conn->event.fde) {
 190                 stream_terminate_connection(srv_conn, "tevent_add_fd() failed");
 191                 return;
 192         }
 193
 194         /* setup to receive internal messages on this connection */
 195         srv_conn->msg_ctx = imessaging_init(srv_conn,
 196                                             lp_ctx,
 197                                             srv_conn->server_id, ev, false);
 198         if (!srv_conn->msg_ctx) {
 199                 stream_terminate_connection(srv_conn, "imessaging_init() failed");
 200                 return;
 201         }
 202
 203         srv_conn->remote_address = socket_get_remote_addr(srv_conn->socket, srv_conn);
 204         if (!srv_conn->remote_address) {
 205                 stream_terminate_connection(srv_conn, "socket_get_remote_addr() failed");
 206                 return;
 207         }
 208
 209         srv_conn->local_address = socket_get_local_addr(srv_conn->socket, srv_conn);
 210         if (!srv_conn->local_address) {
 211                 stream_terminate_connection(srv_conn, "socket_get_local_addr() failed");
 212                 return;
 213         }
 214
 215         {
 216                 TALLOC_CTX *tmp_ctx;
 217                 const char *title;
 218
 219                 tmp_ctx = talloc_new(srv_conn);
 220
 221                 title = talloc_asprintf(tmp_ctx, "conn[%s] c[%s] s[%s] server_id[%s]",
 222                                         stream_socket->ops->name,
 223                                         tsocket_address_string(srv_conn->remote_address, tmp_ctx),
 224                                         tsocket_address_string(srv_conn->local_address, tmp_ctx),
 225                                         server_id_str(tmp_ctx, &server_id));
 226                 if (title) {
 227                         stream_connection_set_title(srv_conn, title);
 228                 }
 229                 talloc_free(tmp_ctx);
 230         }
 231
 232         /* we're now ready to start receiving events on this stream */
 233         TEVENT_FD_READABLE(srv_conn->event.fde);
 234
 235         /* call the server specific accept code */
 236         stream_socket->ops->accept_connection(srv_conn);
 237 }
 238
 239
 240 /*
 241   called when someone opens a connection to one of our listening ports
 242 */
 243 static void stream_accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
 244                                   uint16_t flags, void *private_data)
 245 {
 246         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 247
 248         /* ask the process model to create us a process for this new
 249            connection.  When done, it calls stream_new_connection()
 250            with the newly created socket */
 251         stream_socket->model_ops->accept_connection(ev, stream_socket->lp_ctx,
 252                                                     stream_socket->sock,
 253                                                     stream_new_connection, stream_socket);
 254 }
 255
 256 /*
 257   setup a listen stream socket
 258   if you pass *port == 0, then a port > 1024 is used
 259
 260   FIXME: This function is TCP/IP specific - uses an int rather than
 261          a string for the port. Should leave allocating a port nr
 262          to the socket implementation - JRV20070903
 263  */
 264 NTSTATUS stream_setup_socket(TALLOC_CTX *mem_ctx,
 265                              struct tevent_context *event_context,
 266                              struct loadparm_context *lp_ctx,
 267                              const struct model_ops *model_ops,
 268                              const struct stream_server_ops *stream_ops,
 269                              const char *family,
 270                              const char *sock_addr,
 271                              uint16_t *port,
 272                              const char *socket_options,
 273                              void *private_data)
 274 {
 275         NTSTATUS status;
 276         struct stream_socket *stream_socket;
 277         struct socket_address *socket_address;
 278         struct tevent_fd *fde;
 279         int i;
 280         struct sockaddr_storage ss;
 281
 282         stream_socket = talloc_zero(mem_ctx, struct stream_socket);
 283         NT_STATUS_HAVE_NO_MEMORY(stream_socket);
 284
 285         if (strcmp(family, "ip") == 0) {
 286                 /* we will get the real family from the address itself */
 287                 if (!interpret_string_addr(&ss, sock_addr, 0)) {
 288                         talloc_free(stream_socket);
 289                         return NT_STATUS_INVALID_ADDRESS;
 290                 }
 291
 292                 socket_address = socket_address_from_sockaddr_storage(stream_socket, &ss, port?*port:0);
 293                 NT_STATUS_HAVE_NO_MEMORY_AND_FREE(socket_address, stream_socket);
 294
 295                 status = socket_create(socket_address->family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 296                 NT_STATUS_NOT_OK_RETURN(status);
 297         } else {
 298                 status = socket_create(family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 299                 NT_STATUS_NOT_OK_RETURN(status);
 300
 301                 /* this is for non-IP sockets, eg. unix domain sockets */
 302                 socket_address = socket_address_from_strings(stream_socket,
 303                                                              stream_socket->sock->backend_name,
 304                                                              sock_addr, port?*port:0);
 305                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 306         }
 307
 308
 309         talloc_steal(stream_socket, stream_socket->sock);
 310
 311         stream_socket->lp_ctx = talloc_reference(stream_socket, lp_ctx);
 312
 313         /* ready to listen */
 314         status = socket_set_option(stream_socket->sock, "SO_KEEPALIVE", NULL);
 315         NT_STATUS_NOT_OK_RETURN(status);
 316
 317         if (socket_options != NULL) {
 318                 status = socket_set_option(stream_socket->sock, socket_options, NULL);
 319                 NT_STATUS_NOT_OK_RETURN(status);
 320         }
 321
 322         /* TODO: set socket ACL's (host allow etc) here when they're
 323          * implemented */
 324
 325         /* Some sockets don't have a port, or are just described from
 326          * the string.  We are indicating this by having port == NULL */
 327         if (!port) {
 328                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 329         } else if (*port == 0) {
 330                 for (i=SERVER_TCP_LOW_PORT;i<= SERVER_TCP_HIGH_PORT;i++) {
 331                         socket_address->port = i;
 332                         status = socket_listen(stream_socket->sock, socket_address,
 333                                                SERVER_LISTEN_BACKLOG, 0);
 334                         if (NT_STATUS_IS_OK(status)) {
 335                                 *port = i;
 336                                 break;
 337                         }
 338                 }
 339         } else {
 340                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 341         }
 342
 343         if (!NT_STATUS_IS_OK(status)) {
 344                 DEBUG(0,("Failed to listen on %s:%u - %s\n",
 345                          sock_addr, port ? (unsigned int)(*port) : 0,
 346                          nt_errstr(status)));
 347                 talloc_free(stream_socket);
 348                 return status;
 349         }
 350
 351         /* Add the FD from the newly created socket into the event
 352          * subsystem.  it will call the accept handler whenever we get
 353          * new connections */
 354
 355         fde = tevent_add_fd(event_context, stream_socket->sock,
 356                             socket_get_fd(stream_socket->sock),
 357                             TEVENT_FD_READ,
 358                             stream_accept_handler, stream_socket);
 359         if (!fde) {
 360                 DEBUG(0,("Failed to setup fd event\n"));
 361                 talloc_free(stream_socket);
 362                 return NT_STATUS_NO_MEMORY;
 363         }
 364
 365         /* we let events system to the close on the socket. This avoids
 366          * nasty interactions with waiting for talloc to close the socket. */
 367         tevent_fd_set_close_fn(fde, socket_tevent_fd_close_fn);
 368         socket_set_flags(stream_socket->sock, SOCKET_FLAG_NOCLOSE);
 369
 370         stream_socket->private_data     = talloc_reference(stream_socket, private_data);
 371         stream_socket->ops              = stream_ops;
 372         stream_socket->event_ctx        = event_context;
 373         stream_socket->model_ops        = model_ops;
 374
 375         return NT_STATUS_OK;
 376 }
 377
 378
 379 /*
 380   setup a connection title
 381 */
 382 void stream_connection_set_title(struct stream_connection *conn, const char *title)
 383 {
 384         conn->model_ops->set_title(conn->event.ctx, title);
 385 }