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