send_common.c

   1 /*
   2  * Copyright (C) 2005-2014 Andre Noll <maan@tuebingen.mpg.de>
   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 <netinet/in.h>
  10 #include <sys/socket.h>
  11 #include <regex.h>
  12 #include <osl.h>
  13 #include <arpa/inet.h>
  14 #include <sys/un.h>
  15 #include <netdb.h>
  16
  17 #include "para.h"
  18 #include "error.h"
  19 #include "string.h"
  20 #include "fd.h"
  21 #include "net.h"
  22 #include "list.h"
  23 #include "afh.h"
  24 #include "afs.h"
  25 #include "server.h"
  26 #include "acl.h"
  27 #include "send.h"
  28 #include "close_on_fork.h"
  29 #include "chunk_queue.h"
  30 #include "sched.h"
  31 #include "vss.h"
  32
  33 /** Clients will be kicked if there are more than that many bytes pending. */
  34 #define MAX_CQ_BYTES 40000
  35
  36 /**
  37  * Open a passive socket of given layer4 type.
  38  *
  39  * Set the resulting file descriptor to nonblocking mode and add it to the list
  40  * of fds that are being closed in the child process when the server calls
  41  * fork().
  42  *
  43  * \param l4type The transport-layer protocol.
  44  * \param port The port number.
  45  *
  46  * \return The listening fd on success, negative on errors.
  47  */
  48 static int open_sender(unsigned l4type, int port)
  49 {
  50         int fd, ret = para_listen_simple(l4type, port);
  51
  52         if (ret < 0)
  53                 return ret;
  54         fd = ret;
  55         ret = mark_fd_nonblocking(fd);
  56         if (ret < 0) {
  57                 close(fd);
  58                 return ret;
  59         }
  60         add_close_on_fork_list(fd);
  61         return fd;
  62 }
  63
  64 /**
  65  * Shut down a client connected to a paraslash sender.
  66  *
  67  * \param sc The client to shut down.
  68  * \param ss The sender whose clients are to be shut down.
  69  *
  70  * Close the file descriptor given by \a sc, remove it from the close-on-fork
  71  * list, destroy the chunk queue of this client, delete the client from the
  72  * list of connected clients and free the sender_client struct.
  73  *
  74  * \sa shutdown_clients().
  75  */
  76 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
  77 {
  78         PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
  79         free(sc->name);
  80         close(sc->fd);
  81         del_close_on_fork_list(sc->fd);
  82         cq_destroy(sc->cq);
  83         list_del(&sc->node);
  84         free(sc->private_data);
  85         free(sc);
  86         ss->num_clients--;
  87 }
  88
  89 /**
  90  * Shut down all clients connected to a paraslash sender.
  91  *
  92  * \param ss The sender whose clients are to be shut down.
  93  *
  94  * This just loops over all connected clients and calls shutdown_client()
  95  * for each client.
  96  */
  97 void shutdown_clients(struct sender_status *ss)
  98 {
  99         struct sender_client *sc, *tmp;
 100         list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
 101                 shutdown_client(sc, ss);
 102 }
 103
 104 /**
 105  * Try to empty the chunk queue for this fd.
 106  *
 107  * \param fd The file descriptor.
 108  * \param cq The list of queued chunks.
 109  *
 110  * \return Negative on errors, zero if not everything was sent, one otherwise.
 111  */
 112 int send_queued_chunks(int fd, struct chunk_queue *cq)
 113 {
 114         struct queued_chunk *qc;
 115         while ((qc = cq_peek(cq))) {
 116                 const char *buf;
 117                 size_t len;
 118                 int ret;
 119
 120                 cq_get(qc, &buf, &len);
 121                 ret = xwrite(fd, buf, len);
 122                 if (ret < 0)
 123                         return ret;
 124                 cq_update(cq, ret);
 125                 if (ret != len)
 126                         return 0;
 127                 cq_dequeue(cq);
 128         }
 129         return 1;
 130 }
 131
 132 /**
 133  * Initialize a struct sender status.
 134  *
 135  * \param ss The struct to initialize.
 136  * \param access_arg The array of access arguments given at the command line.
 137  * \param num_access_args The number of elements in \a access_arg.
 138  * \param port The tcp or dccp port to listen on.
 139  * \param max_clients The maximal number of simultaneous connections.
 140  * \param default_deny Whether a blacklist should be used for access control.
 141  */
 142 void init_sender_status(struct sender_status *ss, char **access_arg,
 143         int num_access_args, int port, int max_clients, int default_deny)
 144 {
 145         ss->listen_fd = -1;
 146         INIT_LIST_HEAD(&ss->client_list);
 147         ss->port = port;
 148         acl_init(&ss->acl, access_arg, num_access_args);
 149         ss->num_clients = 0;
 150         ss->max_clients = max_clients;
 151         ss->default_deny = default_deny;
 152 }
 153
 154 /**
 155  * Return a string containing the current status of a sender.
 156  *
 157  * \param ss The sender.
 158  * \param name Used for printing the header line.
 159  *
 160  * \return The string printed in the "si" command.
 161  */
 162 char *generic_sender_status(struct sender_status *ss, const char *name)
 163 {
 164         char *clnts = NULL, *ret;
 165         struct sender_client *sc, *tmp_sc;
 166
 167         char *acl_contents = acl_get_contents(&ss->acl);
 168         list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
 169                 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
 170                 free(clnts);
 171                 clnts = tmp;
 172         }
 173         ret = make_message(
 174                 "status: %s\n"
 175                 "port: %s\n"
 176                 "number of connected clients: %d\n"
 177                 "maximal number of clients: %d%s\n"
 178                 "connected clients: %s\n"
 179                 "access %s list: %s\n",
 180                 (ss->listen_fd >= 0)? "on" : "off",
 181                 stringify_port(ss->port, strcmp(name, "http") ? "dccp" : "tcp"),
 182                 ss->num_clients,
 183                 ss->max_clients,
 184                 ss->max_clients > 0? "" : " (unlimited)",
 185                 clnts? clnts : "(none)",
 186                 ss->default_deny? "allow" : "deny",
 187                 acl_contents? acl_contents : "(empty)"
 188         );
 189         free(acl_contents);
 190         free(clnts);
 191         return ret;
 192 }
 193
 194 /**
 195  * Allow connections from the given range of IP addresses.
 196  *
 197  * \param scd Contains the IP and the netmask.
 198  * \param ss The sender.
 199  *
 200  * \sa generic_com_deny().
 201  */
 202 void generic_com_allow(struct sender_command_data *scd,
 203                 struct sender_status *ss)
 204 {
 205         acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 206 }
 207
 208 /**
 209  * Deny connections from the given range of IP addresses.
 210  *
 211  * \param scd see \ref generic_com_allow().
 212  * \param ss see \ref generic_com_allow().
 213  *
 214  * \sa generic_com_allow().
 215  */
 216 void generic_com_deny(struct sender_command_data *scd,
 217                 struct sender_status *ss)
 218 {
 219         acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
 220 }
 221
 222 /**
 223  * Activate a paraslash sender.
 224  *
 225  * \param ss The sender to activate.
 226  * \param protocol The symbolic name of the transport-layer protocol.
 227  *
 228  * \return Standard.
 229  */
 230 int generic_com_on(struct sender_status *ss, unsigned protocol)
 231 {
 232         int ret;
 233
 234         if (ss->listen_fd >= 0)
 235                 return 1;
 236         ret = open_sender(protocol, ss->port);
 237         if (ret < 0)
 238                 return ret;
 239         ss->listen_fd = ret;
 240         return 1;
 241 }
 242
 243 /**
 244  * Deactivate a paraslash sender.
 245  *
 246  * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
 247  *
 248  * \param ss The sender to deactivate.
 249  *
 250  * \sa \ref del_close_on_fork_list(), shutdown_clients().
 251  */
 252 void generic_com_off(struct sender_status *ss)
 253 {
 254         if (ss->listen_fd < 0)
 255                 return;
 256         PARA_NOTICE_LOG("closing port %d\n", ss->port);
 257         close(ss->listen_fd);
 258         del_close_on_fork_list(ss->listen_fd);
 259         shutdown_clients(ss);
 260         ss->listen_fd = -1;
 261 }
 262
 263 /**
 264  * Accept a connection on the socket this server is listening on.
 265  *
 266  * \param ss The sender whose listening fd is ready for reading.
 267  * \param rfds Passed to para_accept(),
 268  *
 269  * This must be called only if the socket fd of \a ss is ready for reading.  It
 270  * calls para_accept() to accept the connection and performs the following
 271  * actions on the resulting file descriptor \a fd:
 272  *
 273  *      - Checks whether the maximal number of connections are exceeded.
 274  *      - Sets \a fd to nonblocking mode.
 275  *      - Checks the acl of the sender to find out whether connections
 276  *        are allowed from the IP of the connecting peer.
 277  *      - Increases the number of connections for this sender.
 278  *      - Creates and initializes a new chunk queue for queuing network
 279  *        packets that can not be sent immediately.
 280  *      - Allocates a new struct sender_client and fills in its \a fd, \a cq
 281  *        and \a name members.
 282  *      - Adds \a fd to the list of connected clients for this sender.
 283  *      - Adds \a fd to the list of file descriptors that should be closed
 284  *        in the child process when the server calls fork().
 285  *
 286  * \return A pointer to the allocated sender_client structure on success, \p
 287  * NULL on errors.
 288  *
 289  * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
 290  * \ref cq_new(), \ref add_close_on_fork_list().
 291  */
 292 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds)
 293 {
 294         struct sender_client *sc;
 295         int fd, ret;
 296
 297         if (ss->listen_fd < 0)
 298                 return NULL;
 299         ret = para_accept(ss->listen_fd, rfds, NULL, 0, &fd);
 300         if (ret < 0)
 301                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 302         if (ret <= 0)
 303                 return NULL;
 304         ret = -E_MAX_CLIENTS;
 305         if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
 306                 goto err_out;
 307         ret = mark_fd_nonblocking(fd);
 308         if (ret < 0)
 309                 goto err_out;
 310         ret = acl_check_access(fd, &ss->acl, ss->default_deny);
 311         if (ret < 0)
 312                 goto err_out;
 313         ss->num_clients++;
 314         sc = para_calloc(sizeof(*sc));
 315         sc->fd = fd;
 316         sc->name = para_strdup(remote_name(fd));
 317         sc->cq = cq_new(MAX_CQ_BYTES);
 318         para_list_add(&sc->node, &ss->client_list);
 319         add_close_on_fork_list(fd);
 320         PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
 321                 sc->name, fd);
 322         return sc;
 323 err_out:
 324         PARA_WARNING_LOG("%s\n", para_strerror(-ret));
 325         close(fd);
 326         return NULL;
 327 }
 328
 329 /**
 330  * Get the generic help text.
 331  *
 332  * \return A dynamically allocated string containing the help text for
 333  * a paraslash sender.
 334  */
 335 char *generic_sender_help(void)
 336 {
 337         return make_message(
 338                 "usage: {on|off}\n"
 339                 "usage: {allow|deny} IP[/netmask]\n"
 340                 "       where mask defaults to 32\n"
 341                 "example: allow 192.168.0.1/24\n"
 342         );
 343 }
 344
 345 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
 346 {
 347         int32_t val;
 348         char *a = para_strdup(arg),
 349              *b = strchr(a, ':'),
 350              *c = strrchr(a, ':');
 351         int ret = -E_COMMAND_SYNTAX;
 352
 353         if (!b || !c)
 354                 goto out;
 355         *b = *c = '\0';
 356
 357         ret = para_atoi32(a, &val);
 358         if (ret < 0)
 359                 goto out;
 360
 361         /* optional max_slice_bytes (0 means "use MTU") */
 362         if (b == c) {
 363                 scd->max_slice_bytes = 0;
 364         } else {
 365                 if (val < 0 || val > 65535)
 366                         goto fec_einval;
 367                 scd->max_slice_bytes = val;
 368
 369                 ret = para_atoi32(b + 1, &val);
 370                 if (ret < 0)
 371                         goto out;
 372         }
 373
 374         /* k = data_slices_per_group */
 375         if (val < 0 || val > 255)
 376                 goto fec_einval;
 377         scd->data_slices_per_group = val;
 378
 379         /* n = slices_per_group */
 380         ret = para_atoi32(c + 1, &val);
 381         if (ret < 0)
 382                 goto out;
 383         if (val < 0 || val < scd->data_slices_per_group)
 384                 goto fec_einval;
 385         scd->slices_per_group = val;
 386         ret = 0;
 387 out:
 388         free(a);
 389         return ret;
 390 fec_einval:
 391         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 392         goto out;
 393 }
 394
 395 /**
 396  * Parse a FEC URL string.
 397  *
 398  * \param arg the URL string to parse.
 399  * \param scd The structure containing host, port and the FEC parameters.
 400  *
 401  * \return Standard.
 402  *
 403  * A FEC URL consists of an ordinary URL string according to RFC 3986,
 404  * optionally followed by a slash and the three FEC parameters slice_size,
 405  * data_slices_per_group and slices_per_group. The three FEC parameters are
 406  * separated by colons.
 407  *
 408  * \sa \ref parse_url().
 409  */
 410 int parse_fec_url(const char *arg, struct sender_command_data *scd)
 411 {
 412         char *a = para_strdup(arg), *p = strchr(a, '/');
 413         int ret = 0;
 414
 415         /* default fec parameters */
 416         scd->max_slice_bytes       = 0;
 417         scd->data_slices_per_group = 14;
 418         scd->slices_per_group      = 16;
 419
 420         if (p) {
 421                 *p = '\0';
 422                 ret = parse_fec_parms(p + 1, scd);
 423                 if (ret < 0)
 424                         goto out;
 425         }
 426         if (!parse_url(a, scd->host, sizeof(scd->host), &scd->port))
 427                 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 428 out:
 429         free(a);
 430         return ret;
 431 }