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