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