send_common.c

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