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/util/server_id.h"
  27 #include "lib/messaging/irpc.h"
  28 #include "cluster/cluster.h"
  29 #include "param/param.h"
  30 #include "../lib/tsocket/tsocket.h"
  31 #include "lib/util/util_net.h"
  32
  33 /* the range of ports to try for dcerpc over tcp endpoints */
  34 #define SERVER_TCP_LOW_PORT  49152
  35 #define SERVER_TCP_HIGH_PORT 65535
  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         if (srv_conn->processing) {
  65                 DEBUG(3,("Terminating connection deferred - '%s'\n", reason));
  66         } else {
  67                 DEBUG(3,("Terminating connection - '%s'\n", reason));
  68         }
  69
  70         srv_conn->terminate = reason;
  71
  72         if (srv_conn->processing) {
  73                 /*
  74                  * if we're currently inside the stream_io_handler(),
  75                  * defer the termination to the end of stream_io_hendler()
  76                  *
  77                  * and we don't want to read or write to the connection...
  78                  */
  79                 tevent_fd_set_flags(srv_conn->event.fde, 0);
  80                 return;
  81         }
  82
  83         talloc_free(srv_conn->event.fde);
  84         srv_conn->event.fde = NULL;
  85         imessaging_cleanup(srv_conn->msg_ctx);
  86         model_ops->terminate(event_ctx, srv_conn->lp_ctx, reason);
  87         talloc_free(srv_conn);
  88 }
  89
  90 /**
  91   the select loop has indicated that a stream is ready for IO
  92 */
  93 static void stream_io_handler(struct stream_connection *conn, uint16_t flags)
  94 {
  95         conn->processing++;
  96         if (flags & TEVENT_FD_WRITE) {
  97                 conn->ops->send_handler(conn, flags);
  98         } else if (flags & TEVENT_FD_READ) {
  99                 conn->ops->recv_handler(conn, flags);
 100         }
 101         conn->processing--;
 102
 103         if (conn->terminate) {
 104                 stream_terminate_connection(conn, conn->terminate);
 105         }
 106 }
 107
 108 void stream_io_handler_fde(struct tevent_context *ev, struct tevent_fd *fde,
 109                                   uint16_t flags, void *private_data)
 110 {
 111         struct stream_connection *conn = talloc_get_type(private_data,
 112                                                          struct stream_connection);
 113         stream_io_handler(conn, flags);
 114 }
 115
 116 void stream_io_handler_callback(void *private_data, uint16_t flags)
 117 {
 118         struct stream_connection *conn = talloc_get_type(private_data,
 119                                                          struct stream_connection);
 120         stream_io_handler(conn, flags);
 121 }
 122
 123 /*
 124   this creates a stream_connection from an already existing connection,
 125   used for protocols, where a client connection needs to switched into
 126   a server connection
 127 */
 128 NTSTATUS stream_new_connection_merge(struct tevent_context *ev,
 129                                      struct loadparm_context *lp_ctx,
 130                                      const struct model_ops *model_ops,
 131                                      const struct stream_server_ops *stream_ops,
 132                                      struct imessaging_context *msg_ctx,
 133                                      void *private_data,
 134                                      struct stream_connection **_srv_conn)
 135 {
 136         struct stream_connection *srv_conn;
 137
 138         srv_conn = talloc_zero(ev, struct stream_connection);
 139         NT_STATUS_HAVE_NO_MEMORY(srv_conn);
 140
 141         srv_conn->private_data  = private_data;
 142         srv_conn->model_ops     = model_ops;
 143         srv_conn->socket        = NULL;
 144         srv_conn->server_id     = cluster_id(0, 0);
 145         srv_conn->ops           = stream_ops;
 146         srv_conn->msg_ctx       = msg_ctx;
 147         srv_conn->event.ctx     = ev;
 148         srv_conn->lp_ctx        = lp_ctx;
 149         srv_conn->event.fde     = NULL;
 150
 151         *_srv_conn = srv_conn;
 152         return NT_STATUS_OK;
 153 }
 154
 155 /*
 156   called when a new socket connection has been established. This is called in the process
 157   context of the new process (if appropriate)
 158 */
 159 static void stream_new_connection(struct tevent_context *ev,
 160                                   struct loadparm_context *lp_ctx,
 161                                   struct socket_context *sock,
 162                                   struct server_id server_id, void *private_data)
 163 {
 164         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 165         struct stream_connection *srv_conn;
 166
 167         srv_conn = talloc_zero(ev, struct stream_connection);
 168         if (!srv_conn) {
 169                 DEBUG(0,("talloc(mem_ctx, struct stream_connection) failed\n"));
 170                 return;
 171         }
 172
 173         talloc_steal(srv_conn, sock);
 174
 175         srv_conn->private_data  = stream_socket->private_data;
 176         srv_conn->model_ops     = stream_socket->model_ops;
 177         srv_conn->socket        = sock;
 178         srv_conn->server_id     = server_id;
 179         srv_conn->ops           = stream_socket->ops;
 180         srv_conn->event.ctx     = ev;
 181         srv_conn->lp_ctx        = lp_ctx;
 182
 183         if (!socket_check_access(sock, "smbd", lpcfg_hosts_allow(NULL, lpcfg_default_service(lp_ctx)), lpcfg_hosts_deny(NULL, lpcfg_default_service(lp_ctx)))) {
 184                 stream_terminate_connection(srv_conn, "denied by access rules");
 185                 return;
 186         }
 187
 188         srv_conn->event.fde     = tevent_add_fd(ev, srv_conn, socket_get_fd(sock),
 189                                                 0, stream_io_handler_fde, srv_conn);
 190         if (!srv_conn->event.fde) {
 191                 stream_terminate_connection(srv_conn, "tevent_add_fd() failed");
 192                 return;
 193         }
 194
 195         /* setup to receive internal messages on this connection */
 196         srv_conn->msg_ctx = imessaging_init(srv_conn,
 197                                             lp_ctx,
 198                                             srv_conn->server_id, ev);
 199         if (!srv_conn->msg_ctx) {
 200                 stream_terminate_connection(srv_conn, "imessaging_init() failed");
 201                 return;
 202         }
 203
 204         srv_conn->remote_address = socket_get_remote_addr(srv_conn->socket, srv_conn);
 205         if (!srv_conn->remote_address) {
 206                 stream_terminate_connection(srv_conn, "socket_get_remote_addr() failed");
 207                 return;
 208         }
 209
 210         srv_conn->local_address = socket_get_local_addr(srv_conn->socket, srv_conn);
 211         if (!srv_conn->local_address) {
 212                 stream_terminate_connection(srv_conn, "socket_get_local_addr() failed");
 213                 return;
 214         }
 215
 216         {
 217                 TALLOC_CTX *tmp_ctx;
 218                 const char *title;
 219                 struct server_id_buf idbuf;
 220
 221                 tmp_ctx = talloc_new(srv_conn);
 222
 223                 title = talloc_asprintf(tmp_ctx, "conn[%s] c[%s] s[%s] server_id[%s]",
 224                                         stream_socket->ops->name,
 225                                         tsocket_address_string(srv_conn->remote_address, tmp_ctx),
 226                                         tsocket_address_string(srv_conn->local_address, tmp_ctx),
 227                                         server_id_str_buf(server_id, &idbuf));
 228                 if (title) {
 229                         stream_connection_set_title(srv_conn, title);
 230                 }
 231                 talloc_free(tmp_ctx);
 232         }
 233
 234         /* we're now ready to start receiving events on this stream */
 235         TEVENT_FD_READABLE(srv_conn->event.fde);
 236
 237         /* call the server specific accept code */
 238         stream_socket->ops->accept_connection(srv_conn);
 239 }
 240
 241
 242 /*
 243   called when someone opens a connection to one of our listening ports
 244 */
 245 static void stream_accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
 246                                   uint16_t flags, void *private_data)
 247 {
 248         struct stream_socket *stream_socket = talloc_get_type(private_data, struct stream_socket);
 249
 250         /* ask the process model to create us a process for this new
 251            connection.  When done, it calls stream_new_connection()
 252            with the newly created socket */
 253         stream_socket->model_ops->accept_connection(ev, stream_socket->lp_ctx,
 254                                                     stream_socket->sock,
 255                                                     stream_new_connection, stream_socket);
 256 }
 257
 258 /*
 259   setup a listen stream socket
 260   if you pass *port == 0, then a port > 1024 is used
 261
 262   FIXME: This function is TCP/IP specific - uses an int rather than
 263          a string for the port. Should leave allocating a port nr
 264          to the socket implementation - JRV20070903
 265  */
 266 NTSTATUS stream_setup_socket(TALLOC_CTX *mem_ctx,
 267                              struct tevent_context *event_context,
 268                              struct loadparm_context *lp_ctx,
 269                              const struct model_ops *model_ops,
 270                              const struct stream_server_ops *stream_ops,
 271                              const char *family,
 272                              const char *sock_addr,
 273                              uint16_t *port,
 274                              const char *socket_options,
 275                              void *private_data)
 276 {
 277         NTSTATUS status;
 278         struct stream_socket *stream_socket;
 279         struct socket_address *socket_address;
 280         struct tevent_fd *fde;
 281         int i;
 282         struct sockaddr_storage ss;
 283
 284         stream_socket = talloc_zero(mem_ctx, struct stream_socket);
 285         NT_STATUS_HAVE_NO_MEMORY(stream_socket);
 286
 287         if (strcmp(family, "ip") == 0) {
 288                 /* we will get the real family from the address itself */
 289                 if (!interpret_string_addr(&ss, sock_addr, 0)) {
 290                         talloc_free(stream_socket);
 291                         return NT_STATUS_INVALID_ADDRESS;
 292                 }
 293
 294                 socket_address = socket_address_from_sockaddr_storage(stream_socket, &ss, port?*port:0);
 295                 if (socket_address == NULL) {
 296                         TALLOC_FREE(stream_socket);
 297                         return NT_STATUS_NO_MEMORY;
 298                 }
 299
 300                 status = socket_create(socket_address->family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 301                 NT_STATUS_NOT_OK_RETURN(status);
 302         } else {
 303                 status = socket_create(family, SOCKET_TYPE_STREAM, &stream_socket->sock, 0);
 304                 NT_STATUS_NOT_OK_RETURN(status);
 305
 306                 /* this is for non-IP sockets, eg. unix domain sockets */
 307                 socket_address = socket_address_from_strings(stream_socket,
 308                                                              stream_socket->sock->backend_name,
 309                                                              sock_addr, port?*port:0);
 310                 NT_STATUS_HAVE_NO_MEMORY(socket_address);
 311         }
 312
 313
 314         talloc_steal(stream_socket, stream_socket->sock);
 315
 316         stream_socket->lp_ctx = talloc_reference(stream_socket, lp_ctx);
 317
 318         /* ready to listen */
 319         status = socket_set_option(stream_socket->sock, "SO_KEEPALIVE", NULL);
 320         NT_STATUS_NOT_OK_RETURN(status);
 321
 322         if (socket_options != NULL) {
 323                 status = socket_set_option(stream_socket->sock, socket_options, NULL);
 324                 NT_STATUS_NOT_OK_RETURN(status);
 325         }
 326
 327         /* TODO: set socket ACL's (host allow etc) here when they're
 328          * implemented */
 329
 330         /* Some sockets don't have a port, or are just described from
 331          * the string.  We are indicating this by having port == NULL */
 332         if (!port) {
 333                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 334         } else if (*port == 0) {
 335                 for (i=SERVER_TCP_LOW_PORT;i<= SERVER_TCP_HIGH_PORT;i++) {
 336                         socket_address->port = i;
 337                         status = socket_listen(stream_socket->sock, socket_address,
 338                                                SERVER_LISTEN_BACKLOG, 0);
 339                         if (NT_STATUS_IS_OK(status)) {
 340                                 *port = i;
 341                                 break;
 342                         }
 343                 }
 344         } else {
 345                 status = socket_listen(stream_socket->sock, socket_address, SERVER_LISTEN_BACKLOG, 0);
 346         }
 347
 348         if (!NT_STATUS_IS_OK(status)) {
 349                 DEBUG(0,("Failed to listen on %s:%u - %s\n",
 350                          sock_addr, port ? (unsigned int)(*port) : 0,
 351                          nt_errstr(status)));
 352                 talloc_free(stream_socket);
 353                 return status;
 354         }
 355
 356         /* Add the FD from the newly created socket into the event
 357          * subsystem.  it will call the accept handler whenever we get
 358          * new connections */
 359
 360         fde = tevent_add_fd(event_context, stream_socket->sock,
 361                             socket_get_fd(stream_socket->sock),
 362                             TEVENT_FD_READ,
 363                             stream_accept_handler, stream_socket);
 364         if (!fde) {
 365                 DEBUG(0,("Failed to setup fd event\n"));
 366                 talloc_free(stream_socket);
 367                 return NT_STATUS_NO_MEMORY;
 368         }
 369
 370         /* we let events system to the close on the socket. This avoids
 371          * nasty interactions with waiting for talloc to close the socket. */
 372         tevent_fd_set_close_fn(fde, socket_tevent_fd_close_fn);
 373         socket_set_flags(stream_socket->sock, SOCKET_FLAG_NOCLOSE);
 374
 375         stream_socket->private_data     = talloc_reference(stream_socket, private_data);
 376         stream_socket->ops              = stream_ops;
 377         stream_socket->event_ctx        = event_context;
 378         stream_socket->model_ops        = model_ops;
 379
 380         return NT_STATUS_OK;
 381 }
 382
 383
 384 /*
 385   setup a connection title
 386 */
 387 void stream_connection_set_title(struct stream_connection *conn, const char *title)
 388 {
 389         conn->model_ops->set_title(conn->event.ctx, title);
 390 }