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 "para.h"
  11 #include "error.h"
  12 #include "string.h"
  13 #include "fd.h"
  14 #include "net.h"
  15 #include "list.h"
  16 #include "afh.h"
  17 #include "afs.h"
  18 #include "server.h"
  19 #include "acl.h"
  20 #include "send.h"
  21 #include "close_on_fork.h"
  22 #include "chunk_queue.h"
  23 #include "vss.h"
  24
  25 /** Clients will be kicked if there are more than that many bytes pending. */
  26 #define MAX_CQ_BYTES 40000
  27
  28 /**
  29  * Open a passive socket of given layer4 type.
  30  *
  31  * Set the resulting file descriptor to nonblocking mode and add it to the list
  32  * of fds that are being closed in the child process when the server calls
  33  * fork().
  34  *
  35  * \param l4type The transport-layer protocol.
  36  * \param port The port number.
  37  *
  38  * \return The listening fd on success, negative on errors.
  39  */
  40 static int open_sender(unsigned l4type, int port)
  41 {
  42         int fd, ret = para_listen(AF_UNSPEC, l4type, port);
  43
  44         if (ret < 0)
  45                 return ret;
  46         fd = ret;
  47         ret = mark_fd_nonblocking(fd);
  48         if (ret < 0) {
  49                 close(fd);
  50                 return ret;
  51         }
  52         add_close_on_fork_list(fd);
  53         return fd;
  54 }
  55
  56 /**
  57  * Shut down a client connected to a paraslash sender.
  58  *
  59  * \param sc The client to shut down.
  60  * \param ss The sender whose clients are to be shut down.
  61  *
  62  * Close the file descriptor given by \a sc, remove it from the close-on-fork
  63  * list, destroy the chunk queue of this client, delete the client from the
  64  * list of connected clients and free the sender_client struct.
  65  *
  66  * \sa shutdown_clients().
  67  */
  68 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
  69 {
  70         PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
  71         free(sc->name);
  72         close(sc->fd);
  73         del_close_on_fork_list(sc->fd);
  74         cq_destroy(sc->cq);
  75         list_del(&sc->node);
  76         free(sc->private_data);
  77         free(sc);
  78         ss->num_clients--;
  79 }
  80
  81 /**
  82  * Shut down all clients connected to a paraslash sender.
  83  *
  84  * \param ss The sender whose clients are to be shut down.
  85  *
  86  * This just loops over all connected clients and calls shutdown_client()
  87  * for each client.
  88  */
  89 void shutdown_clients(struct sender_status *ss)
  90 {
  91         struct sender_client *sc, *tmp;
  92         list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
  93                 shutdown_client(sc, ss);
  94 }
  95
  96 static int queue_chunk_or_shutdown(struct sender_client *sc,
  97                 struct sender_status *ss, const char *buf, size_t num_bytes)
  98 {
  99         int ret = cq_enqueue(sc->cq, buf, num_bytes);
 100         if (ret < 0)
 101                 shutdown_client(sc, ss);
 102         return ret;
 103 }
 104
 105 /**
 106  * Try to empty the chunk queue for this fd.
 107  *
 108  * \param fd The file descriptor.
 109  * \param cq The list of queued chunks.
 110  * \param max_bytes_per_write Do not send more than this in one go.
 111  *
 112  * \return Negative on errors, zero if not everything was sent, one otherwise.
 113  */
 114 int send_queued_chunks(int fd, struct chunk_queue *cq,
 115                 size_t max_bytes_per_write)
 116 {
 117         struct queued_chunk *qc;
 118         while ((qc = cq_peek(cq))) {
 119                 const char *buf;
 120                 size_t len;
 121                 int ret;
 122                 cq_get(qc, &buf, &len);
 123                 ret = write_nonblock(fd, buf, len, max_bytes_per_write);
 124                 if (ret < 0)
 125                         return ret;
 126                 cq_update(cq, ret);
 127                 if (ret != len)
 128                         return 0;
 129                 cq_dequeue(cq);
 130         }
 131         return 1;
 132 }
 133
 134 /**
 135  * Send one chunk of audio data to a connected client.
 136  *
 137  * \param sc The client.
 138  * \param ss The sender.
 139  * \param max_bytes_per_write Split writes to chunks of at most that many bytes.
 140  * \param current_chunk The number of the chunk to write.
 141  * \param buf The data to write.
 142  * \param len The number of bytes of \a buf.
 143  * \param header_buf The audio file header.
 144  * \param header_len The number of bytes of \a header_buf.
 145  *
 146  * On errors, the client is shut down. If only a part of the buffer could be
 147  * written, the remainder is put into the chunk queue for that client.
 148  */
 149 void send_chunk(struct sender_client *sc, struct sender_status *ss,
 150                 size_t max_bytes_per_write, long unsigned current_chunk,
 151                 const char *buf, size_t len, const char *header_buf,
 152                 size_t header_len)
 153 {
 154         int ret;
 155
 156         if (!sc->header_sent && current_chunk) {
 157                 if (header_buf && header_len > 0) {
 158                         ret = queue_chunk_or_shutdown(sc, ss, header_buf, header_len);
 159                         if (ret < 0)
 160                                 goto out;
 161                 }
 162                 sc->header_sent = 1;
 163         }
 164         ret = send_queued_chunks(sc->fd, sc->cq, max_bytes_per_write);
 165         if (ret < 0) {
 166                 shutdown_client(sc, ss);
 167                 goto out;
 168         }
 169         if (!len)
 170                 goto out;
 171         if (!ret) { /* still data left in the queue */
 172                 ret = queue_chunk_or_shutdown(sc, ss, buf, len);
 173                 goto out;
 174         }
 175         ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
 176         if (ret < 0) {
 177                 shutdown_client(sc, ss);
 178                 goto out;
 179         }
 180         if (ret != len)
 181                 ret = queue_chunk_or_shutdown(sc, ss, buf + ret, len - ret);
 182 out:
 183         if (ret < 0)
 184                 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 185 }
 186
 187 /**
 188  * Initialize a struct sender status.
 189  *
 190  * \param ss The struct to initialize.
 191  * \param access_arg The array of access arguments given at the command line.
 192  * \param num_access_args The number of elements in \a access_arg.
 193  * \param port The tcp or dccp port to listen on.
 194  * \param max_clients The maximal number of simultaneous connections.
 195  * \param default_deny Whether a blacklist should be used for access control.
 196  */
 197 void init_sender_status(struct sender_status *ss, char **access_arg,
 198         int num_access_args, int port, int max_clients, int default_deny)
 199 {
 200         ss->listen_fd = -1;
 201         INIT_LIST_HEAD(&ss->client_list);
 202         ss->port = port;
 203         acl_init(&ss->acl, access_arg, num_access_args);
 204         ss->num_clients = 0;
 205         ss->max_clients = max_clients;
 206         ss->default_deny = default_deny;
 207 }
 208
 209 /**
 210  * Return a string containing the current status of a sender.
 211  *
 212  * \param ss The sender.
 213  * \param name Used for printing the header line.
 214  *
 215  * \return The string printed in the "si" command.
 216  */
 217 char *get_sender_info(struct sender_status *ss, const char *name)
 218 {
 219         char *clnts = NULL, *ret;
 220         struct sender_client *sc, *tmp_sc;
 221
 222         char *acl_contents = acl_get_contents(&ss->acl);
 223         list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
 224                 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
 225                 free(clnts);
 226                 clnts = tmp;
 227         }
 228         ret = make_message(
 229                 "%s sender:\n"
 230                 "\tstatus: %s\n"
 231                 "\tport: %d\n"
 232                 "\tnumber of connected clients: %d\n"
 233                 "\tmaximal number of clients: %d%s\n"
 234                 "\tconnected clients: %s\n"
 235                 "\taccess %s list: %s\n",
 236                 name,
 237                 (ss->listen_fd >= 0)? "on" : "off",
 238                 ss->port,
 239                 ss->num_clients,
 240                 ss->max_clients,
 241                 ss->max_clients > 0? "" : " (unlimited)",
 242                 clnts? clnts : "(none)",
 243                 ss->default_deny? "allow" : "deny",
 244                 acl_contents? acl_contents : "(empty)"
 245         );
 246         free(acl_contents);
 247         free(clnts);
 248         return ret;
 249 }
 250
 251 /**
 252  * Allow connections from the given range of IP addresses.
 253  *
 254  * \param scd Contains the IP and the netmask.
 255  * \param ss The sender.
 256  *
 257  * \sa generic_com_deny().
 258  */
 259 void generic_com_allow(struct sender_command_data *scd,
 260                 struct sender_status *ss)
 261 {
 262         acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 263 }
 264
 265 /**
 266  * Deny connections from the given range of IP addresses.
 267  *
 268  * \param scd see \ref generic_com_allow().
 269  * \param ss see \ref generic_com_allow().
 270  *
 271  * \sa generic_com_allow().
 272  */
 273 void generic_com_deny(struct sender_command_data *scd,
 274                 struct sender_status *ss)
 275 {
 276         acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 277 }
 278
 279 /**
 280  * Activate a paraslash sender.
 281  *
 282  * \param ss The sender to activate.
 283  * \param protocol The symbolic name of the transport-layer protocol.
 284  *
 285  * \return Standard.
 286  */
 287 int generic_com_on(struct sender_status *ss, unsigned protocol)
 288 {
 289         int ret;
 290
 291         if (ss->listen_fd >= 0)
 292                 return 1;
 293         ret = open_sender(protocol, ss->port);
 294         if (ret < 0)
 295                 return ret;
 296         ss->listen_fd = ret;
 297         return 1;
 298 }
 299
 300 /**
 301  * Deactivate a paraslash sender.
 302  *
 303  * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
 304  *
 305  * \param ss The sender to deactivate.
 306  *
 307  * \sa \ref del_close_on_fork_list(), shutdown_clients().
 308  */
 309 void generic_com_off(struct sender_status *ss)
 310 {
 311         if (ss->listen_fd < 0)
 312                 return;
 313         PARA_NOTICE_LOG("closing port %d\n", ss->port);
 314         close(ss->listen_fd);
 315         del_close_on_fork_list(ss->listen_fd);
 316         shutdown_clients(ss);
 317         ss->listen_fd = -1;
 318 }
 319
 320 /**
 321  * Accept a connection on the socket this server is listening on.
 322  *
 323  * \param ss The sender whose listening fd is ready for reading.
 324  *
 325  * This must be called only if the socket fd of \a ss is ready for reading.  It
 326  * calls para_accept() to accept the connection and performs the following
 327  * actions on the resulting file descriptor \a fd:
 328  *
 329  *      - Checks whether the maximal number of connections are exceeded.
 330  *      - Sets \a fd to nonblocking mode.
 331  *      - Checks the acl of the sender to find out whether connections
 332  *        are allowed from the IP of the connecting peer.
 333  *      - Increases the number of connections for this sender.
 334  *      - Creates and initializes a new chunk queue for queuing network
 335  *        packets that can not be sent immediately.
 336  *      - Allocates a new struct sender_client and fills in its \a fd, \a cq
 337  *        and \a name members.
 338  *      - Adds \a fd to the list of connected clients for this sender.
 339  *      - Adds \a fd to the list of file descriptors that should be closed
 340  *        in the child process when the server calls fork().
 341  *
 342  * \return A pointer to the allocated sender_client structure on success, \p
 343  * NULL on errors.
 344  *
 345  * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
 346  * \ref cq_new(), \ref add_close_on_fork_list().
 347  */
 348 struct sender_client *accept_sender_client(struct sender_status *ss)
 349 {
 350         struct sender_client *sc;
 351         int fd, ret = para_accept(ss->listen_fd, NULL, 0);
 352         if (ret < 0) {
 353                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 354                 return NULL;
 355         }
 356         fd = ret;
 357         ret = -E_MAX_CLIENTS;
 358         if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
 359                 goto err_out;
 360         ret = mark_fd_nonblocking(fd);
 361         if (ret < 0)
 362                 goto err_out;
 363         ret = acl_check_access(fd, &ss->acl, ss->default_deny);
 364         if (ret < 0)
 365                 goto err_out;
 366         ss->num_clients++;
 367         sc = para_calloc(sizeof(*sc));
 368         sc->fd = fd;
 369         sc->name = make_message("%s", remote_name(fd));
 370         sc->cq = cq_new(MAX_CQ_BYTES);
 371         para_list_add(&sc->node, &ss->client_list);
 372         add_close_on_fork_list(fd);
 373         PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
 374                 sc->name, fd);
 375         return sc;
 376 err_out:
 377         PARA_WARNING_LOG("%s\n", para_strerror(-ret));
 378         close(fd);
 379         return NULL;
 380 }
 381
 382 /**
 383  * Get the generic help text.
 384  *
 385  * \return A dynamically allocated string containing the help text for
 386  * a paraslash sender.
 387  */
 388 char *generic_sender_help(void)
 389 {
 390         return make_message(
 391                 "usage: {on|off}\n"
 392                 "usage: {allow|deny} IP mask\n"
 393                 "example: allow 127.0.0.1 32\n"
 394         );
 395 }
 396
 397 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
 398 {
 399         int32_t val;
 400         char *a = para_strdup(arg), *b = a, *e = strchr(b, ':');
 401         int ret = -E_COMMAND_SYNTAX;
 402
 403         /* parse max slice bytes */
 404         if (!e)
 405                 goto out;
 406         *e = '\0';
 407         ret = para_atoi32(b, &val);
 408         if (ret < 0)
 409                 goto out;
 410         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 411         if (val < 0 || val > 65535)
 412                 goto out;
 413         scd->max_slice_bytes = val;
 414         /* parse data_slices_per_group */
 415         b = e + 1;
 416         e = strchr(b, ':');
 417         ret = -E_COMMAND_SYNTAX;
 418         if (!e)
 419                 goto out;
 420         *e = '\0';
 421         ret = para_atoi32(b, &val);
 422         if (ret < 0)
 423                 goto out;
 424         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 425         if (val < 0 || val > 255)
 426                 goto out;
 427         scd->data_slices_per_group = val;
 428         /* parse slices_per_group */
 429         b = e + 1;
 430         ret = para_atoi32(b, &val);
 431         if (ret < 0)
 432                 goto out;
 433         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 434         if (val < 0 || val < scd->data_slices_per_group)
 435                 goto out;
 436         scd->slices_per_group = val;
 437         ret = 0;
 438 out:
 439         free(a);
 440         return ret;
 441 }
 442
 443 /**
 444  * Parse a FEC URL string.
 445  *
 446  * \param arg the URL string to parse.
 447  * \param scd The structure containing host, port and the FEC parameters.
 448  *
 449  * \return Standard.
 450  *
 451  * A FEC URL consists of an ordinary URL string according to RFC 3986,
 452  * optionally followed by a slash and the three FEC parameters slice_size,
 453  * data_slices_per_group and slices_per_group. The three FEC parameters are
 454  * separated by colons.
 455  *
 456  * \sa \ref parse_url().
 457  */
 458 int parse_fec_url(const char *arg, struct sender_command_data *scd)
 459 {
 460         int ret;
 461         ssize_t len = sizeof(scd->host);
 462         char *a = para_strdup(arg), *p = strchr(a, '/');
 463
 464         if (p) {
 465                 *p = '\0';
 466                 len = strlen(a);
 467         }
 468         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 469         if (!parse_url(a, scd->host, len, &scd->port))
 470                 goto out;
 471         if (p) {
 472                 ret = parse_fec_parms(p + 1, scd);
 473                 goto out;
 474         }
 475         /* use default fec parameters. */
 476         scd->max_slice_bytes = 1490;
 477         scd->slices_per_group = 16;
 478         scd->data_slices_per_group = 14;
 479         ret = 0;
 480 out:
 481         free(a);
 482         return ret;
 483 }