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 <regex.h>
  10 #include <dirent.h>
  11 #include <osl.h>
  12
  13 #include "para.h"
  14 #include "error.h"
  15 #include "string.h"
  16 #include "fd.h"
  17 #include "net.h"
  18 #include "list.h"
  19 #include "afh.h"
  20 #include "afs.h"
  21 #include "server.h"
  22 #include "acl.h"
  23 #include "send.h"
  24 #include "close_on_fork.h"
  25 #include "chunk_queue.h"
  26 #include "vss.h"
  27
  28 /** Clients will be kicked if there are more than that many bytes pending. */
  29 #define MAX_CQ_BYTES 40000
  30
  31 /**
  32  * Open a passive socket of given layer4 type.
  33  *
  34  * Set the resulting file descriptor to nonblocking mode and add it to the list
  35  * of fds that are being closed in the child process when the server calls
  36  * fork().
  37  *
  38  * \param l4type The transport-layer protocol.
  39  * \param port The port number.
  40  *
  41  * \return The listening fd on success, negative on errors.
  42  */
  43 static int open_sender(unsigned l4type, int port)
  44 {
  45         int fd, ret = para_listen(AF_UNSPEC, l4type, port);
  46
  47         if (ret < 0)
  48                 return ret;
  49         fd = ret;
  50         ret = mark_fd_nonblocking(fd);
  51         if (ret < 0) {
  52                 close(fd);
  53                 return ret;
  54         }
  55         add_close_on_fork_list(fd);
  56         return fd;
  57 }
  58
  59 /**
  60  * Shut down a client connected to a paraslash sender.
  61  *
  62  * \param sc The client to shut down.
  63  * \param ss The sender whose clients are to be shut down.
  64  *
  65  * Close the file descriptor given by \a sc, remove it from the close-on-fork
  66  * list, destroy the chunk queue of this client, delete the client from the
  67  * list of connected clients and free the sender_client struct.
  68  *
  69  * \sa shutdown_clients().
  70  */
  71 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
  72 {
  73         PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
  74         free(sc->name);
  75         close(sc->fd);
  76         del_close_on_fork_list(sc->fd);
  77         cq_destroy(sc->cq);
  78         list_del(&sc->node);
  79         free(sc->private_data);
  80         free(sc);
  81         ss->num_clients--;
  82 }
  83
  84 /**
  85  * Shut down all clients connected to a paraslash sender.
  86  *
  87  * \param ss The sender whose clients are to be shut down.
  88  *
  89  * This just loops over all connected clients and calls shutdown_client()
  90  * for each client.
  91  */
  92 void shutdown_clients(struct sender_status *ss)
  93 {
  94         struct sender_client *sc, *tmp;
  95         list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
  96                 shutdown_client(sc, ss);
  97 }
  98
  99 static int queue_chunk_or_shutdown(struct sender_client *sc,
 100                 struct sender_status *ss, const char *buf, size_t num_bytes)
 101 {
 102         int ret = cq_enqueue(sc->cq, buf, num_bytes);
 103         if (ret < 0)
 104                 shutdown_client(sc, ss);
 105         return ret;
 106 }
 107
 108 /**
 109  * Try to empty the chunk queue for this fd.
 110  *
 111  * \param fd The file descriptor.
 112  * \param cq The list of queued chunks.
 113  * \param max_bytes_per_write Do not send more than this in one go.
 114  *
 115  * \return Negative on errors, zero if not everything was sent, one otherwise.
 116  */
 117 int send_queued_chunks(int fd, struct chunk_queue *cq,
 118                 size_t max_bytes_per_write)
 119 {
 120         struct queued_chunk *qc;
 121         while ((qc = cq_peek(cq))) {
 122                 const char *buf;
 123                 size_t len;
 124                 int ret;
 125                 cq_get(qc, &buf, &len);
 126                 ret = write_nonblock(fd, buf, len, max_bytes_per_write);
 127                 if (ret < 0)
 128                         return ret;
 129                 cq_update(cq, ret);
 130                 if (ret != len)
 131                         return 0;
 132                 cq_dequeue(cq);
 133         }
 134         return 1;
 135 }
 136
 137 /**
 138  * Send one chunk of audio data to a connected client.
 139  *
 140  * \param sc The client.
 141  * \param ss The sender.
 142  * \param max_bytes_per_write Split writes to chunks of at most that many bytes.
 143  * \param current_chunk The number of the chunk to write.
 144  * \param buf The data to write.
 145  * \param len The number of bytes of \a buf.
 146  * \param header_buf The audio file header.
 147  * \param header_len The number of bytes of \a header_buf.
 148  *
 149  * On errors, the client is shut down. If only a part of the buffer could be
 150  * written, the remainder is put into the chunk queue for that client.
 151  */
 152 void send_chunk(struct sender_client *sc, struct sender_status *ss,
 153                 size_t max_bytes_per_write, long unsigned current_chunk,
 154                 const char *buf, size_t len, const char *header_buf,
 155                 size_t header_len)
 156 {
 157         int ret;
 158
 159         if (!sc->header_sent && current_chunk) {
 160                 if (header_buf && header_len > 0) {
 161                         ret = queue_chunk_or_shutdown(sc, ss, header_buf, header_len);
 162                         if (ret < 0)
 163                                 goto out;
 164                 }
 165         }
 166         sc->header_sent = 1;
 167         ret = send_queued_chunks(sc->fd, sc->cq, max_bytes_per_write);
 168         if (ret < 0) {
 169                 shutdown_client(sc, ss);
 170                 goto out;
 171         }
 172         if (!len)
 173                 goto out;
 174         if (!ret) { /* still data left in the queue */
 175                 ret = queue_chunk_or_shutdown(sc, ss, buf, len);
 176                 goto out;
 177         }
 178         ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
 179         if (ret < 0) {
 180                 shutdown_client(sc, ss);
 181                 goto out;
 182         }
 183         if (ret != len)
 184                 ret = queue_chunk_or_shutdown(sc, ss, buf + ret, len - ret);
 185 out:
 186         if (ret < 0)
 187                 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 188 }
 189
 190 /**
 191  * Initialize a struct sender status.
 192  *
 193  * \param ss The struct to initialize.
 194  * \param access_arg The array of access arguments given at the command line.
 195  * \param num_access_args The number of elements in \a access_arg.
 196  * \param port The tcp or dccp port to listen on.
 197  * \param max_clients The maximal number of simultaneous connections.
 198  * \param default_deny Whether a blacklist should be used for access control.
 199  */
 200 void init_sender_status(struct sender_status *ss, char **access_arg,
 201         int num_access_args, int port, int max_clients, int default_deny)
 202 {
 203         ss->listen_fd = -1;
 204         INIT_LIST_HEAD(&ss->client_list);
 205         ss->port = port;
 206         acl_init(&ss->acl, access_arg, num_access_args);
 207         ss->num_clients = 0;
 208         ss->max_clients = max_clients;
 209         ss->default_deny = default_deny;
 210 }
 211
 212 /**
 213  * Return a string containing the current status of a sender.
 214  *
 215  * \param ss The sender.
 216  * \param name Used for printing the header line.
 217  *
 218  * \return The string printed in the "si" command.
 219  */
 220 char *get_sender_info(struct sender_status *ss, const char *name)
 221 {
 222         char *clnts = NULL, *ret;
 223         struct sender_client *sc, *tmp_sc;
 224
 225         char *acl_contents = acl_get_contents(&ss->acl);
 226         list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
 227                 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
 228                 free(clnts);
 229                 clnts = tmp;
 230         }
 231         ret = make_message(
 232                 "%s sender:\n"
 233                 "\tstatus: %s\n"
 234                 "\tport: %d\n"
 235                 "\tnumber of connected clients: %d\n"
 236                 "\tmaximal number of clients: %d%s\n"
 237                 "\tconnected clients: %s\n"
 238                 "\taccess %s list: %s\n",
 239                 name,
 240                 (ss->listen_fd >= 0)? "on" : "off",
 241                 ss->port,
 242                 ss->num_clients,
 243                 ss->max_clients,
 244                 ss->max_clients > 0? "" : " (unlimited)",
 245                 clnts? clnts : "(none)",
 246                 ss->default_deny? "allow" : "deny",
 247                 acl_contents? acl_contents : "(empty)"
 248         );
 249         free(acl_contents);
 250         free(clnts);
 251         return ret;
 252 }
 253
 254 /**
 255  * Allow connections from the given range of IP addresses.
 256  *
 257  * \param scd Contains the IP and the netmask.
 258  * \param ss The sender.
 259  *
 260  * \sa generic_com_deny().
 261  */
 262 void generic_com_allow(struct sender_command_data *scd,
 263                 struct sender_status *ss)
 264 {
 265         acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 266 }
 267
 268 /**
 269  * Deny connections from the given range of IP addresses.
 270  *
 271  * \param scd see \ref generic_com_allow().
 272  * \param ss see \ref generic_com_allow().
 273  *
 274  * \sa generic_com_allow().
 275  */
 276 void generic_com_deny(struct sender_command_data *scd,
 277                 struct sender_status *ss)
 278 {
 279         acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 280 }
 281
 282 /**
 283  * Activate a paraslash sender.
 284  *
 285  * \param ss The sender to activate.
 286  * \param protocol The symbolic name of the transport-layer protocol.
 287  *
 288  * \return Standard.
 289  */
 290 int generic_com_on(struct sender_status *ss, unsigned protocol)
 291 {
 292         int ret;
 293
 294         if (ss->listen_fd >= 0)
 295                 return 1;
 296         ret = open_sender(protocol, ss->port);
 297         if (ret < 0)
 298                 return ret;
 299         ss->listen_fd = ret;
 300         return 1;
 301 }
 302
 303 /**
 304  * Deactivate a paraslash sender.
 305  *
 306  * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
 307  *
 308  * \param ss The sender to deactivate.
 309  *
 310  * \sa \ref del_close_on_fork_list(), shutdown_clients().
 311  */
 312 void generic_com_off(struct sender_status *ss)
 313 {
 314         if (ss->listen_fd < 0)
 315                 return;
 316         PARA_NOTICE_LOG("closing port %d\n", ss->port);
 317         close(ss->listen_fd);
 318         del_close_on_fork_list(ss->listen_fd);
 319         shutdown_clients(ss);
 320         ss->listen_fd = -1;
 321 }
 322
 323 /**
 324  * Accept a connection on the socket this server is listening on.
 325  *
 326  * \param ss The sender whose listening fd is ready for reading.
 327  *
 328  * This must be called only if the socket fd of \a ss is ready for reading.  It
 329  * calls para_accept() to accept the connection and performs the following
 330  * actions on the resulting file descriptor \a fd:
 331  *
 332  *      - Checks whether the maximal number of connections are exceeded.
 333  *      - Sets \a fd to nonblocking mode.
 334  *      - Checks the acl of the sender to find out whether connections
 335  *        are allowed from the IP of the connecting peer.
 336  *      - Increases the number of connections for this sender.
 337  *      - Creates and initializes a new chunk queue for queuing network
 338  *        packets that can not be sent immediately.
 339  *      - Allocates a new struct sender_client and fills in its \a fd, \a cq
 340  *        and \a name members.
 341  *      - Adds \a fd to the list of connected clients for this sender.
 342  *      - Adds \a fd to the list of file descriptors that should be closed
 343  *        in the child process when the server calls fork().
 344  *
 345  * \return A pointer to the allocated sender_client structure on success, \p
 346  * NULL on errors.
 347  *
 348  * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
 349  * \ref cq_new(), \ref add_close_on_fork_list().
 350  */
 351 struct sender_client *accept_sender_client(struct sender_status *ss)
 352 {
 353         struct sender_client *sc;
 354         int fd, ret = para_accept(ss->listen_fd, NULL, 0);
 355         if (ret < 0) {
 356                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 357                 return NULL;
 358         }
 359         fd = ret;
 360         ret = -E_MAX_CLIENTS;
 361         if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
 362                 goto err_out;
 363         ret = mark_fd_nonblocking(fd);
 364         if (ret < 0)
 365                 goto err_out;
 366         ret = acl_check_access(fd, &ss->acl, ss->default_deny);
 367         if (ret < 0)
 368                 goto err_out;
 369         ss->num_clients++;
 370         sc = para_calloc(sizeof(*sc));
 371         sc->fd = fd;
 372         sc->name = make_message("%s", remote_name(fd));
 373         sc->cq = cq_new(MAX_CQ_BYTES);
 374         para_list_add(&sc->node, &ss->client_list);
 375         add_close_on_fork_list(fd);
 376         PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
 377                 sc->name, fd);
 378         return sc;
 379 err_out:
 380         PARA_WARNING_LOG("%s\n", para_strerror(-ret));
 381         close(fd);
 382         return NULL;
 383 }
 384
 385 /**
 386  * Get the generic help text.
 387  *
 388  * \return A dynamically allocated string containing the help text for
 389  * a paraslash sender.
 390  */
 391 char *generic_sender_help(void)
 392 {
 393         return make_message(
 394                 "usage: {on|off}\n"
 395                 "usage: {allow|deny} IP[/netmask]\n"
 396                 "       where mask defaults to 32\n"
 397                 "example: allow 192.168.0.1/24\n"
 398         );
 399 }
 400
 401 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
 402 {
 403         int32_t val;
 404         char *a = para_strdup(arg), *b = a, *e = strchr(b, ':');
 405         int ret = -E_COMMAND_SYNTAX;
 406
 407         /* parse max slice bytes */
 408         if (!e)
 409                 goto out;
 410         *e = '\0';
 411         ret = para_atoi32(b, &val);
 412         if (ret < 0)
 413                 goto out;
 414         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 415         if (val < 0 || val > 65535)
 416                 goto out;
 417         scd->max_slice_bytes = val;
 418         /* parse data_slices_per_group */
 419         b = e + 1;
 420         e = strchr(b, ':');
 421         ret = -E_COMMAND_SYNTAX;
 422         if (!e)
 423                 goto out;
 424         *e = '\0';
 425         ret = para_atoi32(b, &val);
 426         if (ret < 0)
 427                 goto out;
 428         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 429         if (val < 0 || val > 255)
 430                 goto out;
 431         scd->data_slices_per_group = val;
 432         /* parse slices_per_group */
 433         b = e + 1;
 434         ret = para_atoi32(b, &val);
 435         if (ret < 0)
 436                 goto out;
 437         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 438         if (val < 0 || val < scd->data_slices_per_group)
 439                 goto out;
 440         scd->slices_per_group = val;
 441         ret = 0;
 442 out:
 443         free(a);
 444         return ret;
 445 }
 446
 447 /**
 448  * Parse a FEC URL string.
 449  *
 450  * \param arg the URL string to parse.
 451  * \param scd The structure containing host, port and the FEC parameters.
 452  *
 453  * \return Standard.
 454  *
 455  * A FEC URL consists of an ordinary URL string according to RFC 3986,
 456  * optionally followed by a slash and the three FEC parameters slice_size,
 457  * data_slices_per_group and slices_per_group. The three FEC parameters are
 458  * separated by colons.
 459  *
 460  * \sa \ref parse_url().
 461  */
 462 int parse_fec_url(const char *arg, struct sender_command_data *scd)
 463 {
 464         int ret;
 465         ssize_t len = sizeof(scd->host);
 466         char *a = para_strdup(arg), *p = strchr(a, '/');
 467
 468         if (p) {
 469                 *p = '\0';
 470                 len = strlen(a);
 471         }
 472         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 473         if (!parse_url(a, scd->host, len, &scd->port))
 474                 goto out;
 475         if (p) {
 476                 ret = parse_fec_parms(p + 1, scd);
 477                 goto out;
 478         }
 479         /* use default fec parameters. */
 480         scd->max_slice_bytes = 1490;
 481         scd->slices_per_group = 16;
 482         scd->data_slices_per_group = 14;
 483         ret = 0;
 484 out:
 485         free(a);
 486         return ret;
 487 }