send_common.c

   1 /*
   2  * Copyright (C) 2005-2010 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_simple(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 /**
 100  * Try to empty the chunk queue for this fd.
 101  *
 102  * \param fd The file descriptor.
 103  * \param cq The list of queued chunks.
 104  *
 105  * \return Negative on errors, zero if not everything was sent, one otherwise.
 106  */
 107 int send_queued_chunks(int fd, struct chunk_queue *cq)
 108 {
 109         struct queued_chunk *qc;
 110         while ((qc = cq_peek(cq))) {
 111                 const char *buf;
 112                 size_t len;
 113                 int ret;
 114
 115                 cq_get(qc, &buf, &len);
 116                 ret = write_nonblock(fd, buf, len);
 117                 if (ret < 0)
 118                         return ret;
 119                 cq_update(cq, ret);
 120                 if (ret != len)
 121                         return 0;
 122                 cq_dequeue(cq);
 123         }
 124         return 1;
 125 }
 126
 127 /**
 128  * Initialize a struct sender status.
 129  *
 130  * \param ss The struct to initialize.
 131  * \param access_arg The array of access arguments given at the command line.
 132  * \param num_access_args The number of elements in \a access_arg.
 133  * \param port The tcp or dccp port to listen on.
 134  * \param max_clients The maximal number of simultaneous connections.
 135  * \param default_deny Whether a blacklist should be used for access control.
 136  */
 137 void init_sender_status(struct sender_status *ss, char **access_arg,
 138         int num_access_args, int port, int max_clients, int default_deny)
 139 {
 140         ss->listen_fd = -1;
 141         INIT_LIST_HEAD(&ss->client_list);
 142         ss->port = port;
 143         acl_init(&ss->acl, access_arg, num_access_args);
 144         ss->num_clients = 0;
 145         ss->max_clients = max_clients;
 146         ss->default_deny = default_deny;
 147 }
 148
 149 /**
 150  * Return a string containing the current status of a sender.
 151  *
 152  * \param ss The sender.
 153  * \param name Used for printing the header line.
 154  *
 155  * \return The string printed in the "si" command.
 156  */
 157 char *get_sender_info(struct sender_status *ss, const char *name)
 158 {
 159         char *clnts = NULL, *ret;
 160         struct sender_client *sc, *tmp_sc;
 161
 162         char *acl_contents = acl_get_contents(&ss->acl);
 163         list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
 164                 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
 165                 free(clnts);
 166                 clnts = tmp;
 167         }
 168         ret = make_message(
 169                 "%s sender:\n"
 170                 "\tstatus: %s\n"
 171                 "\tport: %s\n"
 172                 "\tnumber of connected clients: %d\n"
 173                 "\tmaximal number of clients: %d%s\n"
 174                 "\tconnected clients: %s\n"
 175                 "\taccess %s list: %s\n",
 176                 name,
 177                 (ss->listen_fd >= 0)? "on" : "off",
 178                 stringify_port(ss->port, strcmp(name, "http") ? "dccp" : "tcp"),
 179                 ss->num_clients,
 180                 ss->max_clients,
 181                 ss->max_clients > 0? "" : " (unlimited)",
 182                 clnts? clnts : "(none)",
 183                 ss->default_deny? "allow" : "deny",
 184                 acl_contents? acl_contents : "(empty)"
 185         );
 186         free(acl_contents);
 187         free(clnts);
 188         return ret;
 189 }
 190
 191 /**
 192  * Allow connections from the given range of IP addresses.
 193  *
 194  * \param scd Contains the IP and the netmask.
 195  * \param ss The sender.
 196  *
 197  * \sa generic_com_deny().
 198  */
 199 void generic_com_allow(struct sender_command_data *scd,
 200                 struct sender_status *ss)
 201 {
 202         acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 203 }
 204
 205 /**
 206  * Deny connections from the given range of IP addresses.
 207  *
 208  * \param scd see \ref generic_com_allow().
 209  * \param ss see \ref generic_com_allow().
 210  *
 211  * \sa generic_com_allow().
 212  */
 213 void generic_com_deny(struct sender_command_data *scd,
 214                 struct sender_status *ss)
 215 {
 216         acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 217 }
 218
 219 /**
 220  * Activate a paraslash sender.
 221  *
 222  * \param ss The sender to activate.
 223  * \param protocol The symbolic name of the transport-layer protocol.
 224  *
 225  * \return Standard.
 226  */
 227 int generic_com_on(struct sender_status *ss, unsigned protocol)
 228 {
 229         int ret;
 230
 231         if (ss->listen_fd >= 0)
 232                 return 1;
 233         ret = open_sender(protocol, ss->port);
 234         if (ret < 0)
 235                 return ret;
 236         ss->listen_fd = ret;
 237         return 1;
 238 }
 239
 240 /**
 241  * Deactivate a paraslash sender.
 242  *
 243  * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
 244  *
 245  * \param ss The sender to deactivate.
 246  *
 247  * \sa \ref del_close_on_fork_list(), shutdown_clients().
 248  */
 249 void generic_com_off(struct sender_status *ss)
 250 {
 251         if (ss->listen_fd < 0)
 252                 return;
 253         PARA_NOTICE_LOG("closing port %d\n", ss->port);
 254         close(ss->listen_fd);
 255         del_close_on_fork_list(ss->listen_fd);
 256         shutdown_clients(ss);
 257         ss->listen_fd = -1;
 258 }
 259
 260 /**
 261  * Accept a connection on the socket this server is listening on.
 262  *
 263  * \param ss The sender whose listening fd is ready for reading.
 264  *
 265  * This must be called only if the socket fd of \a ss is ready for reading.  It
 266  * calls para_accept() to accept the connection and performs the following
 267  * actions on the resulting file descriptor \a fd:
 268  *
 269  *      - Checks whether the maximal number of connections are exceeded.
 270  *      - Sets \a fd to nonblocking mode.
 271  *      - Checks the acl of the sender to find out whether connections
 272  *        are allowed from the IP of the connecting peer.
 273  *      - Increases the number of connections for this sender.
 274  *      - Creates and initializes a new chunk queue for queuing network
 275  *        packets that can not be sent immediately.
 276  *      - Allocates a new struct sender_client and fills in its \a fd, \a cq
 277  *        and \a name members.
 278  *      - Adds \a fd to the list of connected clients for this sender.
 279  *      - Adds \a fd to the list of file descriptors that should be closed
 280  *        in the child process when the server calls fork().
 281  *
 282  * \return A pointer to the allocated sender_client structure on success, \p
 283  * NULL on errors.
 284  *
 285  * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
 286  * \ref cq_new(), \ref add_close_on_fork_list().
 287  */
 288 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds)
 289 {
 290         struct sender_client *sc;
 291         int fd, ret;
 292
 293         if (ss->listen_fd < 0)
 294                 return NULL;
 295         ret = para_accept(ss->listen_fd, rfds, NULL, 0, &fd);
 296         if (ret < 0)
 297                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 298         if (ret <= 0)
 299                 return NULL;
 300         ret = -E_MAX_CLIENTS;
 301         if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
 302                 goto err_out;
 303         ret = mark_fd_nonblocking(fd);
 304         if (ret < 0)
 305                 goto err_out;
 306         ret = acl_check_access(fd, &ss->acl, ss->default_deny);
 307         if (ret < 0)
 308                 goto err_out;
 309         ss->num_clients++;
 310         sc = para_calloc(sizeof(*sc));
 311         sc->fd = fd;
 312         sc->name = para_strdup(remote_name(fd));
 313         sc->cq = cq_new(MAX_CQ_BYTES);
 314         para_list_add(&sc->node, &ss->client_list);
 315         add_close_on_fork_list(fd);
 316         PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
 317                 sc->name, fd);
 318         return sc;
 319 err_out:
 320         PARA_WARNING_LOG("%s\n", para_strerror(-ret));
 321         close(fd);
 322         return NULL;
 323 }
 324
 325 /**
 326  * Get the generic help text.
 327  *
 328  * \return A dynamically allocated string containing the help text for
 329  * a paraslash sender.
 330  */
 331 char *generic_sender_help(void)
 332 {
 333         return make_message(
 334                 "usage: {on|off}\n"
 335                 "usage: {allow|deny} IP[/netmask]\n"
 336                 "       where mask defaults to 32\n"
 337                 "example: allow 192.168.0.1/24\n"
 338         );
 339 }
 340
 341 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
 342 {
 343         int32_t val;
 344         char *a = para_strdup(arg), *b = a, *e = strchr(b, ':');
 345         int ret = -E_COMMAND_SYNTAX;
 346
 347         /* parse max slice bytes */
 348         if (!e)
 349                 goto out;
 350         *e = '\0';
 351         ret = para_atoi32(b, &val);
 352         if (ret < 0)
 353                 goto out;
 354         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 355         if (val < 0 || val > 65535)
 356                 goto out;
 357         scd->max_slice_bytes = val;
 358         /* parse data_slices_per_group */
 359         b = e + 1;
 360         e = strchr(b, ':');
 361         ret = -E_COMMAND_SYNTAX;
 362         if (!e)
 363                 goto out;
 364         *e = '\0';
 365         ret = para_atoi32(b, &val);
 366         if (ret < 0)
 367                 goto out;
 368         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 369         if (val < 0 || val > 255)
 370                 goto out;
 371         scd->data_slices_per_group = val;
 372         /* parse slices_per_group */
 373         b = e + 1;
 374         ret = para_atoi32(b, &val);
 375         if (ret < 0)
 376                 goto out;
 377         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 378         if (val < 0 || val < scd->data_slices_per_group)
 379                 goto out;
 380         scd->slices_per_group = val;
 381         ret = 0;
 382 out:
 383         free(a);
 384         return ret;
 385 }
 386
 387 /**
 388  * Parse a FEC URL string.
 389  *
 390  * \param arg the URL string to parse.
 391  * \param scd The structure containing host, port and the FEC parameters.
 392  *
 393  * \return Standard.
 394  *
 395  * A FEC URL consists of an ordinary URL string according to RFC 3986,
 396  * optionally followed by a slash and the three FEC parameters slice_size,
 397  * data_slices_per_group and slices_per_group. The three FEC parameters are
 398  * separated by colons.
 399  *
 400  * \sa \ref parse_url().
 401  */
 402 int parse_fec_url(const char *arg, struct sender_command_data *scd)
 403 {
 404         int ret;
 405         ssize_t len = sizeof(scd->host);
 406         char *a = para_strdup(arg), *p = strchr(a, '/');
 407
 408         if (p) {
 409                 *p = '\0';
 410                 len = strlen(a);
 411         }
 412         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 413         if (!parse_url(a, scd->host, len, &scd->port))
 414                 goto out;
 415         if (p) {
 416                 ret = parse_fec_parms(p + 1, scd);
 417                 goto out;
 418         }
 419         /* use default fec parameters. */
 420         scd->max_slice_bytes = 0;
 421         scd->slices_per_group = 16;
 422         scd->data_slices_per_group = 14;
 423         ret = 0;
 424 out:
 425         free(a);
 426         return ret;
 427 }