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/socket/socket.h"
  27 #include "smbd/service.h"
  28 #include "smbd/service_stream.h"
  29 #include "lib/messaging/irpc.h"
  30 #include "cluster/cluster.h"
  31 #include "param/param.h"
  32
  33 /* the range of ports to try for dcerpc over tcp endpoints */
  34 #define SERVER_TCP_LOW_PORT  1024
  35 #define SERVER_TCP_HIGH_PORT 1300
  36
  37 /* size of listen() backlog in smbd */
  38 #define SERVER_LISTEN_BACKLOG 10
  39
  40
  41 /*
  42   private structure for a single listening stream socket
  43 */
  44 struct stream_socket {
  45         const struct stream_server_ops *ops;
  46         struct loadparm_context *lp_ctx;
  47         struct tevent_context *event_ctx;
  48         const struct model_ops *model_ops;
  49         struct socket_context *sock;
  50         void *private_data;
  51 };
  52
  53
  54 /*
  55   close the socket and shutdown a stream_connection
  56 */
  57 void stream_terminate_connection(struct stream_connection *srv_conn, const char *reason)
  58 {
  59         struct tevent_context *event_ctx = srv_conn->event.ctx;
  60         const struct model_ops *model_ops = srv_conn->model_ops;
  61
  62         if (!reason) reason = "unknown reason";
  63
  64         DEBUG(3,("Terminating connection - '%s'\n", reason));
  65
  66         srv_conn->terminate = reason;
  67
  68         if (srv_conn->processing) {
  69                 /*
  70                  * if we're currently inside the stream_io_handler(),
  71                  * defer the termination to the end of stream_io_hendler()
  72                  *
  73                  * and we don't want to read or write to the connection...
  74                  */
  75                 tevent_fd_set_flags(srv_conn->event.fde, 0);
  76                 return;
  77         }
  78
  79         talloc_free(srv_conn->event.fde);
  80         srv_conn->event.fde = NULL;
  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 static 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                                      struct socket_context *sock,
 127                                      const struct stream_server_ops *stream_ops,
 128                                      struct messaging_context *msg_ctx,
 129                                      void *private_data,
 130                                      struct stream_connection **_srv_conn)
 131 {
 132         struct stream_connection *srv_conn;
 133
 134         srv_conn = talloc_zero(ev, struct stream_connection);
 135         NT_STATUS_HAVE_NO_MEMORY(srv_conn);
 136
 137         talloc_steal(srv_conn, sock);
 138
 139         srv_conn->private_data  = private_data;
 140         srv_conn->model_ops     = model_ops;
 141         srv_conn->socket        = sock;
 142         srv_conn->server_id     = cluster_id(0, 0);
 143         srv_conn->ops           = stream_ops;
 144         srv_conn->msg_ctx       = msg_ctx;
 145         srv_conn->event.ctx     = ev;
 146         srv_conn->lp_ctx        = lp_ctx;
 147         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 148                                                 TEVENT_FD_READ,
 149                                                 stream_io_handler_fde, srv_conn);
 150         if (!srv_conn->event.fde) {
 151                 talloc_free(srv_conn);
 152                 return NT_STATUS_NO_MEMORY;
 153         }
 154
 155         *_srv_conn = srv_conn;
 156         return NT_STATUS_OK;
 157 }
 158
 159 /*
 160   called when a new socket connection has been established. This is called in the process
 161   context of the new process (if appropriate)
 162 */
 163 static void stream_new_connection(struct tevent_context *ev,
 164                                   struct loadparm_context *lp_ctx,
 165                                   struct socket_context *sock,
 166                                   struct server_id server_id, void *private_data)
 167 {
 168         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 169         struct stream_connection *srv_conn;
 170         struct socket_address *c, *s;
 171
 172         srv_conn = talloc_zero(ev, struct stream_connection);
 173         if (!srv_conn) {
 174                 DEBUG(0,("talloc(mem_ctx, struct stream_connection) failed\n"));
 175                 return;
 176         }
 177
 178         talloc_steal(srv_conn, sock);
 179
 180         srv_conn->private_data  = stream_socket->private_data;
 181         srv_conn->model_ops     = stream_socket->model_ops;
 182         srv_conn->socket        = sock;
 183         srv_conn->server_id     = server_id;
 184         srv_conn->ops           = stream_socket->ops;
 185         srv_conn->event.ctx     = ev;
 186         srv_conn->lp_ctx        = lp_ctx;
 187
 188         if (!socket_check_access(sock, "smbd", lp_hostsallow(NULL, lp_default_service(lp_ctx)), lp_hostsdeny(NULL, lp_default_service(lp_ctx)))) {
 189                 stream_terminate_connection(srv_conn, "denied by access rules");
 190                 return;
 191         }
 192
 193         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 194                                                 0, stream_io_handler_fde, srv_conn);
 195         if (!srv_conn->event.fde) {
 196                 stream_terminate_connection(srv_conn, "tevent_add_fd() failed");
 197                 return;
 198         }
 199
 200         /* setup to receive internal messages on this connection */
 201         srv_conn->msg_ctx = messaging_init(srv_conn,
 202                                            lp_messaging_path(srv_conn, lp_ctx),
 203                                            srv_conn->server_id,
 204                                            lp_iconv_convenience(lp_ctx),
 205                                            ev);
 206         if (!srv_conn->msg_ctx) {
 207                 stream_terminate_connection(srv_conn, "messaging_init() failed");
 208                 return;
 209         }
 210
 211         c = socket_get_peer_addr(sock, ev);
 212         s = socket_get_my_addr(sock, ev);
 213         if (s && c) {
 214                 const char *title;
 215                 title = talloc_asprintf(s, "conn[%s] c[%s:%u] s[%s:%u] server_id[%s]",
 216                                         stream_socket->ops->name,
 217                                         c->addr, c->port, s->addr, s->port,
 218                                         cluster_id_string(s, server_id));
 219                 if (title) {
 220                         stream_connection_set_title(srv_conn, title);
 221                 }
 222         }
 223         talloc_free(c);
 224         talloc_free(s);
 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(struct tevent_context *event_context,
 259                              struct loadparm_context *lp_ctx,
 260                              const struct model_ops *model_ops,
 261                              const struct stream_server_ops *stream_ops,
 262                              const char *family,
 263                              const char *sock_addr,
 264                              uint16_t *port,
 265                              const char *socket_options,
 266                              void *private_data)
 267 {
 268         NTSTATUS status;
 269         struct stream_socket *stream_socket;
 270         struct socket_address *socket_address;
 271         struct tevent_fd *fde;
 272         int i;
 273
 274         stream_socket = talloc_zero(event_context, struct stream_socket);
 275         NT_STATUS_HAVE_NO_MEMORY(stream_socket);
 276
 277         status = socket_create(family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 278         NT_STATUS_NOT_OK_RETURN(status);
 279
 280         talloc_steal(stream_socket, stream_socket->sock);
 281
 282         stream_socket->lp_ctx = talloc_reference(stream_socket, lp_ctx);
 283
 284         /* ready to listen */
 285         status = socket_set_option(stream_socket->sock, "SO_KEEPALIVE", NULL);
 286         NT_STATUS_NOT_OK_RETURN(status);
 287
 288         if (socket_options != NULL) {
 289                 status = socket_set_option(stream_socket->sock, socket_options, NULL);
 290                 NT_STATUS_NOT_OK_RETURN(status);
 291         }
 292
 293         /* TODO: set socket ACL's (host allow etc) here when they're
 294          * implemented */
 295
 296         /* Some sockets don't have a port, or are just described from
 297          * the string.  We are indicating this by having port == NULL */
 298         if (!port) {
 299                 socket_address = socket_address_from_strings(stream_socket,
 300                                                              stream_socket->sock->backend_name,
 301                                                              sock_addr, 0);
 302                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 303                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 304                 talloc_free(socket_address);
 305
 306         } else if (*port == 0) {
 307                 for (i=SERVER_TCP_LOW_PORT;i<= SERVER_TCP_HIGH_PORT;i++) {
 308                         socket_address = socket_address_from_strings(stream_socket,
 309                                                                      stream_socket->sock->backend_name,
 310                                                                      sock_addr, i);
 311                         NT_STATUS_HAVE_NO_MEMORY(socket_address);
 312                         status = socket_listen(stream_socket->sock, socket_address,
 313                                                SERVER_LISTEN_BACKLOG, 0);
 314                         talloc_free(socket_address);
 315                         if (NT_STATUS_IS_OK(status)) {
 316                                 *port = i;
 317                                 break;
 318                         }
 319                 }
 320         } else {
 321                 socket_address = socket_address_from_strings(stream_socket,
 322                                                              stream_socket->sock->backend_name,
 323                                                              sock_addr, *port);
 324                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 325                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 326                 talloc_free(socket_address);
 327         }
 328
 329         if (!NT_STATUS_IS_OK(status)) {
 330                 DEBUG(0,("Failed to listen on %s:%u - %s\n",
 331                         sock_addr, *port, nt_errstr(status)));
 332                 talloc_free(stream_socket);
 333                 return status;
 334         }
 335
 336         /* Add the FD from the newly created socket into the event
 337          * subsystem.  it will call the accept handler whenever we get
 338          * new connections */
 339
 340         fde = tevent_add_fd(event_context, stream_socket->sock,
 341                             socket_get_fd(stream_socket->sock),
 342                             TEVENT_FD_READ,
 343                             stream_accept_handler, stream_socket);
 344         if (!fde) {
 345                 DEBUG(0,("Failed to setup fd event\n"));
 346                 talloc_free(stream_socket);
 347                 return NT_STATUS_NO_MEMORY;
 348         }
 349
 350         /* we let events system to the close on the socket. This avoids
 351          * nasty interactions with waiting for talloc to close the socket. */
 352         tevent_fd_set_close_fn(fde, socket_tevent_fd_close_fn);
 353         socket_set_flags(stream_socket->sock, SOCKET_FLAG_NOCLOSE);
 354
 355         stream_socket->private_data     = talloc_reference(stream_socket, private_data);
 356         stream_socket->ops              = stream_ops;
 357         stream_socket->event_ctx        = event_context;
 358         stream_socket->model_ops        = model_ops;
 359
 360         return NT_STATUS_OK;
 361 }
 362
 363 /*
 364   setup a connection title
 365 */
 366 void stream_connection_set_title(struct stream_connection *conn, const char *title)
 367 {
 368         conn->model_ops->set_title(conn->event.ctx, title);
 369 }