send_common.c

   1 /*
   2  * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file send_common.c Functions used by more than one paraslash sender. */
   8
   9 #include <dirent.h>
  10 #include <osl.h>
  11 #include "para.h"
  12 #include "error.h"
  13 #include "string.h"
  14 #include "fd.h"
  15 #include "net.h"
  16 #include "list.h"
  17 #include "afh.h"
  18 #include "afs.h"
  19 #include "server.h"
  20 #include "acl.h"
  21 #include "send.h"
  22 #include "close_on_fork.h"
  23 #include "chunk_queue.h"
  24 #include "vss.h"
  25
  26 /** Clients will be kicked if there are more than that many bytes pending. */
  27 #define MAX_CQ_BYTES 40000
  28
  29 /**
  30  * Open a passive socket of given layer4 type.
  31  *
  32  * Set the resulting file descriptor to nonblocking mode and add it to the list
  33  * of fds that are being closed in the child process when the server calls
  34  * fork().
  35  *
  36  * \param l4type The transport-layer protocol.
  37  * \param port The port number.
  38  *
  39  * \return The listening fd on success, negative on errors.
  40  */
  41 static int open_sender(unsigned l4type, int port)
  42 {
  43         int fd, ret = para_listen(AF_UNSPEC, l4type, port);
  44
  45         if (ret < 0)
  46                 return ret;
  47         fd = ret;
  48         ret = mark_fd_nonblocking(fd);
  49         if (ret < 0) {
  50                 close(fd);
  51                 return ret;
  52         }
  53         add_close_on_fork_list(fd);
  54         return fd;
  55 }
  56
  57 /**
  58  * Shut down a client connected to a paraslash sender.
  59  *
  60  * \param sc The client to shut down.
  61  * \param ss The sender whose clients are to be shut down.
  62  *
  63  * Close the file descriptor given by \a sc, remove it from the close-on-fork
  64  * list, destroy the chunk queue of this client, delete the client from the
  65  * list of connected clients and free the sender_client struct.
  66  *
  67  * \sa shutdown_clients().
  68  */
  69 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
  70 {
  71         PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
  72         free(sc->name);
  73         close(sc->fd);
  74         del_close_on_fork_list(sc->fd);
  75         cq_destroy(sc->cq);
  76         list_del(&sc->node);
  77         free(sc->private_data);
  78         free(sc);
  79         ss->num_clients--;
  80 }
  81
  82 /**
  83  * Shut down all clients connected to a paraslash sender.
  84  *
  85  * \param ss The sender whose clients are to be shut down.
  86  *
  87  * This just loops over all connected clients and calls shutdown_client()
  88  * for each client.
  89  */
  90 void shutdown_clients(struct sender_status *ss)
  91 {
  92         struct sender_client *sc, *tmp;
  93         list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
  94                 shutdown_client(sc, ss);
  95 }
  96
  97 static int queue_chunk_or_shutdown(struct sender_client *sc,
  98                 struct sender_status *ss, const char *buf, size_t num_bytes)
  99 {
 100         int ret = cq_enqueue(sc->cq, buf, num_bytes);
 101         if (ret < 0)
 102                 shutdown_client(sc, ss);
 103         return ret;
 104 }
 105
 106 /**
 107  * Try to empty the chunk queue for this fd.
 108  *
 109  * \param fd The file descriptor.
 110  * \param cq The list of queued chunks.
 111  * \param max_bytes_per_write Do not send more than this in one go.
 112  *
 113  * \return Negative on errors, zero if not everything was sent, one otherwise.
 114  */
 115 int send_queued_chunks(int fd, struct chunk_queue *cq,
 116                 size_t max_bytes_per_write)
 117 {
 118         struct queued_chunk *qc;
 119         while ((qc = cq_peek(cq))) {
 120                 const char *buf;
 121                 size_t len;
 122                 int ret;
 123                 cq_get(qc, &buf, &len);
 124                 ret = write_nonblock(fd, buf, len, max_bytes_per_write);
 125                 if (ret < 0)
 126                         return ret;
 127                 cq_update(cq, ret);
 128                 if (ret != len)
 129                         return 0;
 130                 cq_dequeue(cq);
 131         }
 132         return 1;
 133 }
 134
 135 /**
 136  * Send one chunk of audio data to a connected client.
 137  *
 138  * \param sc The client.
 139  * \param ss The sender.
 140  * \param max_bytes_per_write Split writes to chunks of at most that many bytes.
 141  * \param current_chunk The number of the chunk to write.
 142  * \param buf The data to write.
 143  * \param len The number of bytes of \a buf.
 144  * \param header_buf The audio file header.
 145  * \param header_len The number of bytes of \a header_buf.
 146  *
 147  * On errors, the client is shut down. If only a part of the buffer could be
 148  * written, the remainder is put into the chunk queue for that client.
 149  */
 150 void send_chunk(struct sender_client *sc, struct sender_status *ss,
 151                 size_t max_bytes_per_write, long unsigned current_chunk,
 152                 const char *buf, size_t len, const char *header_buf,
 153                 size_t header_len)
 154 {
 155         int ret;
 156
 157         if (!sc->header_sent && current_chunk) {
 158                 if (header_buf && header_len > 0) {
 159                         ret = queue_chunk_or_shutdown(sc, ss, header_buf, header_len);
 160                         if (ret < 0)
 161                                 goto out;
 162                 }
 163                 sc->header_sent = 1;
 164         }
 165         ret = send_queued_chunks(sc->fd, sc->cq, max_bytes_per_write);
 166         if (ret < 0) {
 167                 shutdown_client(sc, ss);
 168                 goto out;
 169         }
 170         if (!len)
 171                 goto out;
 172         if (!ret) { /* still data left in the queue */
 173                 ret = queue_chunk_or_shutdown(sc, ss, buf, len);
 174                 goto out;
 175         }
 176         ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
 177         if (ret < 0) {
 178                 shutdown_client(sc, ss);
 179                 goto out;
 180         }
 181         if (ret != len)
 182                 ret = queue_chunk_or_shutdown(sc, ss, buf + ret, len - ret);
 183 out:
 184         if (ret < 0)
 185                 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 186 }
 187
 188 /**
 189  * Initialize a struct sender status.
 190  *
 191  * \param ss The struct to initialize.
 192  * \param access_arg The array of access arguments given at the command line.
 193  * \param num_access_args The number of elements in \a access_arg.
 194  * \param port The tcp or dccp port to listen on.
 195  * \param max_clients The maximal number of simultaneous connections.
 196  * \param default_deny Whether a blacklist should be used for access control.
 197  */
 198 void init_sender_status(struct sender_status *ss, char **access_arg,
 199         int num_access_args, int port, int max_clients, int default_deny)
 200 {
 201         ss->listen_fd = -1;
 202         INIT_LIST_HEAD(&ss->client_list);
 203         ss->port = port;
 204         acl_init(&ss->acl, access_arg, num_access_args);
 205         ss->num_clients = 0;
 206         ss->max_clients = max_clients;
 207         ss->default_deny = default_deny;
 208 }
 209
 210 /**
 211  * Return a string containing the current status of a sender.
 212  *
 213  * \param ss The sender.
 214  * \param name Used for printing the header line.
 215  *
 216  * \return The string printed in the "si" command.
 217  */
 218 char *get_sender_info(struct sender_status *ss, const char *name)
 219 {
 220         char *clnts = NULL, *ret;
 221         struct sender_client *sc, *tmp_sc;
 222
 223         char *acl_contents = acl_get_contents(&ss->acl);
 224         list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
 225                 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
 226                 free(clnts);
 227                 clnts = tmp;
 228         }
 229         ret = make_message(
 230                 "%s sender:\n"
 231                 "\tstatus: %s\n"
 232                 "\tport: %d\n"
 233                 "\tnumber of connected clients: %d\n"
 234                 "\tmaximal number of clients: %d%s\n"
 235                 "\tconnected clients: %s\n"
 236                 "\taccess %s list: %s\n",
 237                 name,
 238                 (ss->listen_fd >= 0)? "on" : "off",
 239                 ss->port,
 240                 ss->num_clients,
 241                 ss->max_clients,
 242                 ss->max_clients > 0? "" : " (unlimited)",
 243                 clnts? clnts : "(none)",
 244                 ss->default_deny? "allow" : "deny",
 245                 acl_contents? acl_contents : "(empty)"
 246         );
 247         free(acl_contents);
 248         free(clnts);
 249         return ret;
 250 }
 251
 252 /**
 253  * Allow connections from the given range of IP addresses.
 254  *
 255  * \param scd Contains the IP and the netmask.
 256  * \param ss The sender.
 257  *
 258  * \sa generic_com_deny().
 259  */
 260 void generic_com_allow(struct sender_command_data *scd,
 261                 struct sender_status *ss)
 262 {
 263         acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 264 }
 265
 266 /**
 267  * Deny connections from the given range of IP addresses.
 268  *
 269  * \param scd see \ref generic_com_allow().
 270  * \param ss see \ref generic_com_allow().
 271  *
 272  * \sa generic_com_allow().
 273  */
 274 void generic_com_deny(struct sender_command_data *scd,
 275                 struct sender_status *ss)
 276 {
 277         acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 278 }
 279
 280 /**
 281  * Activate a paraslash sender.
 282  *
 283  * \param ss The sender to activate.
 284  * \param protocol The symbolic name of the transport-layer protocol.
 285  *
 286  * \return Standard.
 287  */
 288 int generic_com_on(struct sender_status *ss, unsigned protocol)
 289 {
 290         int ret;
 291
 292         if (ss->listen_fd >= 0)
 293                 return 1;
 294         ret = open_sender(protocol, ss->port);
 295         if (ret < 0)
 296                 return ret;
 297         ss->listen_fd = ret;
 298         return 1;
 299 }
 300
 301 /**
 302  * Deactivate a paraslash sender.
 303  *
 304  * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
 305  *
 306  * \param ss The sender to deactivate.
 307  *
 308  * \sa \ref del_close_on_fork_list(), shutdown_clients().
 309  */
 310 void generic_com_off(struct sender_status *ss)
 311 {
 312         if (ss->listen_fd < 0)
 313                 return;
 314         PARA_NOTICE_LOG("closing port %d\n", ss->port);
 315         close(ss->listen_fd);
 316         del_close_on_fork_list(ss->listen_fd);
 317         shutdown_clients(ss);
 318         ss->listen_fd = -1;
 319 }
 320
 321 /**
 322  * Accept a connection on the socket this server is listening on.
 323  *
 324  * \param ss The sender whose listening fd is ready for reading.
 325  *
 326  * This must be called only if the socket fd of \a ss is ready for reading.  It
 327  * calls para_accept() to accept the connection and performs the following
 328  * actions on the resulting file descriptor \a fd:
 329  *
 330  *      - Checks whether the maximal number of connections are exceeded.
 331  *      - Sets \a fd to nonblocking mode.
 332  *      - Checks the acl of the sender to find out whether connections
 333  *        are allowed from the IP of the connecting peer.
 334  *      - Increases the number of connections for this sender.
 335  *      - Creates and initializes a new chunk queue for queuing network
 336  *        packets that can not be sent immediately.
 337  *      - Allocates a new struct sender_client and fills in its \a fd, \a cq
 338  *        and \a name members.
 339  *      - Adds \a fd to the list of connected clients for this sender.
 340  *      - Adds \a fd to the list of file descriptors that should be closed
 341  *        in the child process when the server calls fork().
 342  *
 343  * \return A pointer to the allocated sender_client structure on success, \p
 344  * NULL on errors.
 345  *
 346  * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
 347  * \ref cq_new(), \ref add_close_on_fork_list().
 348  */
 349 struct sender_client *accept_sender_client(struct sender_status *ss)
 350 {
 351         struct sender_client *sc;
 352         int fd, ret = para_accept(ss->listen_fd, NULL, 0);
 353         if (ret < 0) {
 354                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 355                 return NULL;
 356         }
 357         fd = ret;
 358         ret = -E_MAX_CLIENTS;
 359         if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
 360                 goto err_out;
 361         ret = mark_fd_nonblocking(fd);
 362         if (ret < 0)
 363                 goto err_out;
 364         ret = acl_check_access(fd, &ss->acl, ss->default_deny);
 365         if (ret < 0)
 366                 goto err_out;
 367         ss->num_clients++;
 368         sc = para_calloc(sizeof(*sc));
 369         sc->fd = fd;
 370         sc->name = make_message("%s", remote_name(fd));
 371         sc->cq = cq_new(MAX_CQ_BYTES);
 372         para_list_add(&sc->node, &ss->client_list);
 373         add_close_on_fork_list(fd);
 374         PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
 375                 sc->name, fd);
 376         return sc;
 377 err_out:
 378         PARA_WARNING_LOG("%s\n", para_strerror(-ret));
 379         close(fd);
 380         return NULL;
 381 }
 382
 383 /**
 384  * Get the generic help text.
 385  *
 386  * \return A dynamically allocated string containing the help text for
 387  * a paraslash sender.
 388  */
 389 char *generic_sender_help(void)
 390 {
 391         return make_message(
 392                 "usage: {on|off}\n"
 393                 "usage: {allow|deny} IP[/netmask]\n"
 394                 "       where mask defaults to 32\n"
 395                 "example: allow 192.168.0.1/24\n"
 396         );
 397 }
 398
 399 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
 400 {
 401         int32_t val;
 402         char *a = para_strdup(arg), *b = a, *e = strchr(b, ':');
 403         int ret = -E_COMMAND_SYNTAX;
 404
 405         /* parse max slice bytes */
 406         if (!e)
 407                 goto out;
 408         *e = '\0';
 409         ret = para_atoi32(b, &val);
 410         if (ret < 0)
 411                 goto out;
 412         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 413         if (val < 0 || val > 65535)
 414                 goto out;
 415         scd->max_slice_bytes = val;
 416         /* parse data_slices_per_group */
 417         b = e + 1;
 418         e = strchr(b, ':');
 419         ret = -E_COMMAND_SYNTAX;
 420         if (!e)
 421                 goto out;
 422         *e = '\0';
 423         ret = para_atoi32(b, &val);
 424         if (ret < 0)
 425                 goto out;
 426         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 427         if (val < 0 || val > 255)
 428                 goto out;
 429         scd->data_slices_per_group = val;
 430         /* parse slices_per_group */
 431         b = e + 1;
 432         ret = para_atoi32(b, &val);
 433         if (ret < 0)
 434                 goto out;
 435         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 436         if (val < 0 || val < scd->data_slices_per_group)
 437                 goto out;
 438         scd->slices_per_group = val;
 439         ret = 0;
 440 out:
 441         free(a);
 442         return ret;
 443 }
 444
 445 /**
 446  * Parse a FEC URL string.
 447  *
 448  * \param arg the URL string to parse.
 449  * \param scd The structure containing host, port and the FEC parameters.
 450  *
 451  * \return Standard.
 452  *
 453  * A FEC URL consists of an ordinary URL string according to RFC 3986,
 454  * optionally followed by a slash and the three FEC parameters slice_size,
 455  * data_slices_per_group and slices_per_group. The three FEC parameters are
 456  * separated by colons.
 457  *
 458  * \sa \ref parse_url().
 459  */
 460 int parse_fec_url(const char *arg, struct sender_command_data *scd)
 461 {
 462         int ret;
 463         ssize_t len = sizeof(scd->host);
 464         char *a = para_strdup(arg), *p = strchr(a, '/');
 465
 466         if (p) {
 467                 *p = '\0';
 468                 len = strlen(a);
 469         }
 470         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 471         if (!parse_url(a, scd->host, len, &scd->port))
 472                 goto out;
 473         if (p) {
 474                 ret = parse_fec_parms(p + 1, scd);
 475                 goto out;
 476         }
 477         /* use default fec parameters. */
 478         scd->max_slice_bytes = 1490;
 479         scd->slices_per_group = 16;
 480         scd->data_slices_per_group = 14;
 481         ret = 0;
 482 out:
 483         free(a);
 484         return ret;
 485 }