udp_send.c

   1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
   2
   3 /** \file udp_send.c Para_server's udp sender. */
   4
   5 #include <netinet/in.h>
   6 #include <sys/socket.h>
   7 #include <regex.h>
   8 #include <sys/types.h>
   9 #include <netinet/udp.h>
  10 #include <net/if.h>
  11 #include <arpa/inet.h>
  12 #include <sys/un.h>
  13 #include <netdb.h>
  14 #include <lopsub.h>
  15
  16 #include "server.lsg.h"
  17 #include "para.h"
  18 #include "error.h"
  19 #include "string.h"
  20 #include "afh.h"
  21 #include "net.h"
  22 #include "server.h"
  23 #include "list.h"
  24 #include "send.h"
  25 #include "sched.h"
  26 #include "vss.h"
  27 #include "portable_io.h"
  28 #include "fd.h"
  29 #include "close_on_fork.h"
  30
  31 /**
  32  * Time window during which ICMP Destination/Port Unreachable messages are
  33  * ignored, covering transient receiver problems such as restarting the
  34  * client, rebooting, reconfiguration, or handover.
  35  */
  36 #define UDP_MAX_UNREACHABLE_TIME 30
  37
  38 /** Describes one entry in the list of targets for the udp sender. */
  39 struct udp_target {
  40         /** Track time (seconds) of last ICMP Port Unreachable error */
  41         time_t last_unreachable;
  42         /** The opaque structure returned by vss_add_fec_client(). */
  43         struct fec_client *fc;
  44         /** The FEC parameters for this target. */
  45         struct fec_client_parms fcp;
  46         /** Whether we already sent the FEC eof packet to this target. */
  47         bool sent_fec_eof;
  48 };
  49
  50 static struct list_head targets;
  51 static int sender_status;
  52
  53 static void udp_close_target(struct sender_client *sc)
  54 {
  55         const char *buf;
  56         size_t len;
  57         struct udp_target *ut = sc->private_data;
  58
  59         if (process_is_command_handler())
  60                 return;
  61         if (ut->sent_fec_eof)
  62                 return;
  63         PARA_NOTICE_LOG("sending FEC EOF\n");
  64         len = vss_get_fec_eof_packet(&buf);
  65         /* Ignore write() errors since we are closing the target anyway. */
  66         if (write(sc->fd, buf, len))
  67                 do_nothing; /* avoid "ignoring return value" warning */
  68         ut->sent_fec_eof = true;
  69 }
  70
  71 static void udp_delete_target(struct sender_client *sc, const char *msg)
  72 {
  73         struct udp_target *ut = sc->private_data;
  74
  75         PARA_NOTICE_LOG("deleting %s (%s) from list\n", sc->name, msg);
  76         udp_close_target(sc);
  77         /* command handlers already called close_listed_fds() */
  78         if (!process_is_command_handler()) {
  79                 close(sc->fd);
  80                 del_close_on_fork_list(sc->fd);
  81         }
  82         vss_del_fec_client(ut->fc);
  83         list_del(&sc->node);
  84         free(sc->name);
  85         free(sc);
  86         free(ut);
  87 }
  88
  89 /**
  90  * Perform AF-independent multicast sender setup.
  91  *
  92  * \param sc    The connected sender client.
  93  *
  94  * \return Zero if okay, negative on error.
  95  */
  96 static int mcast_sender_setup(struct sender_client *sc)
  97 {
  98         struct sockaddr_storage ss;
  99         socklen_t sslen = sizeof(ss);
 100         int ttl = OPT_INT32_VAL(UDP_TTL), id = 0;
 101         const int on = 1;
 102
 103         if (OPT_GIVEN(UDP_MCAST_IFACE)) {
 104                 const char *iface = OPT_STRING_VAL(UDP_MCAST_IFACE);
 105
 106                 id = if_nametoindex(iface);
 107                 if (id == 0)
 108                         PARA_WARNING_LOG("could not resolve interface '%s', "
 109                                         "using default", iface);
 110         }
 111
 112         if (getpeername(sc->fd, (struct sockaddr *)&ss, &sslen) < 0)
 113                 goto err;
 114         assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
 115
 116         /* RFC 3493, 5.2: -1 means 'use kernel default' */
 117         if (ttl < 0 || ttl > 255)
 118                 ttl = -1;
 119
 120         switch (ss.ss_family) {
 121         case AF_INET:
 122                 if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
 123                         return 0;
 124                 if (id != 0) {
 125 #ifdef HAVE_IP_MREQN
 126                         struct ip_mreqn mn;
 127
 128                         memset(&mn, 0, sizeof(mn));
 129                         mn.imr_ifindex = id;
 130                         if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_IF, &mn, sizeof(mn)) < 0)
 131                                 goto err;
 132 #else
 133                         PARA_ERROR_LOG("No support for setting outgoing IPv4 mcast interface.");
 134 #endif
 135                 }
 136                 /*
 137                  * Enable receiving multicast messages generated on the local host
 138                  * At least on Linux, this is enabled by default.
 139                  */
 140                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 141                         break;
 142
 143                 /* Default: use local subnet (do not flood out into the WAN) */
 144                 if (ttl == -1)
 145                         ttl = 1;
 146                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
 147                         break;
 148                 return 0;
 149         case AF_INET6:
 150                 if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
 151                         return 0;
 152                 if (id != 0 &&
 153                     setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &id, sizeof(id)) < 0)
 154                         break;
 155                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 156                         break;
 157                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
 158                         break;
 159                 return 0;
 160         }
 161 err:
 162         return -ERRNO_TO_PARA_ERROR(errno);
 163 }
 164
 165 static void udp_shutdown_targets(void)
 166 {
 167         struct sender_client *sc, *tmp;
 168         list_for_each_entry_safe(sc, tmp, &targets, node)
 169                 udp_close_target(sc);
 170 }
 171
 172 static void udp_shutdown(void)
 173 {
 174         struct sender_client *sc, *tmp;
 175         list_for_each_entry_safe(sc, tmp, &targets, node)
 176                 udp_delete_target(sc, "shutdown");
 177 }
 178
 179 static int udp_resolve_target(const char *url, struct sender_command_data *scd)
 180 {
 181         const char *result;
 182         int ret, port;
 183
 184         ret = parse_fec_url(url, scd);
 185         if (ret)
 186                 return ret;
 187         port = scd->port > 0 ? scd->port : OPT_UINT32_VAL(UDP_DEFAULT_PORT);
 188
 189         ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
 190         if (ret < 0)
 191                 return ret;
 192
 193         result = remote_name(ret);
 194         close(ret);
 195
 196         if (!parse_url(result, scd->host, sizeof(scd->host), &scd->port))
 197                 return -E_ADDRESS_LOOKUP;
 198         return 1;
 199 }
 200
 201 static int udp_com_on(__a_unused struct sender_command_data *scd)
 202 {
 203         sender_status = SENDER_on;
 204         return 1;
 205 }
 206
 207 static int udp_com_off(__a_unused struct sender_command_data *scd)
 208 {
 209         udp_shutdown_targets();
 210         sender_status = SENDER_off;
 211         return 1;
 212 }
 213
 214 static struct sender_client *udp_lookup_target(struct sender_command_data *scd)
 215 {
 216         struct sender_client *sc, *tmp;
 217         char host[MAX_HOSTLEN];
 218         int32_t port;
 219
 220         list_for_each_entry_safe(sc, tmp, &targets, node) {
 221                 parse_url(sc->name, host, sizeof(host), &port);
 222
 223                 /* Unspecified port means wildcard port match */
 224                 if (scd->port > 0 && scd->port != port)
 225                         continue;
 226                 if (strcmp(host, scd->host))
 227                         continue;
 228                 return sc;
 229         }
 230         return NULL;
 231 }
 232
 233 static int udp_com_delete(struct sender_command_data *scd)
 234 {
 235         struct sender_client *sc = udp_lookup_target(scd);
 236
 237         if (sc) {
 238                 udp_delete_target(sc, "com_delete");
 239                 return 1;
 240         }
 241         PARA_NOTICE_LOG("not deleting non-existing target '%s'\n", scd->host);
 242         return -E_TARGET_NOT_FOUND;
 243 }
 244
 245 /** Initialize UDP session and set maximum payload size. */
 246 static int udp_init_fec(struct sender_client *sc)
 247 {
 248         struct udp_target *ut = sc->private_data;
 249         int mps;
 250
 251         PARA_NOTICE_LOG("sending to udp %s\n", sc->name);
 252         ut->sent_fec_eof = false;
 253         mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
 254         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 255         return mps;
 256 }
 257
 258 /** Check and clear socket error if any. */
 259 static int udp_check_socket_state(struct sender_client *sc)
 260 {
 261         struct udp_target *ut = sc->private_data;
 262         int ret;
 263         socklen_t errlen = sizeof(ret);
 264
 265         if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
 266                 PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
 267                 return 0;
 268         } else if (ret == 0) {
 269                 return 0;
 270         } else if (ret == ECONNREFUSED) {
 271                 time_t dist = now->tv_sec - ut->last_unreachable;
 272
 273                 if (dist <= UDP_MAX_UNREACHABLE_TIME) {
 274                         return 0;
 275                 } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
 276                         ut->last_unreachable = now->tv_sec;
 277                         return 0;
 278                 } else {
 279                         /*
 280                          * unreachable_time < dist <= 2 * unreachable_time
 281                          * No errors are allowed during this time window.
 282                          */
 283                         PARA_NOTICE_LOG("Evicting %s after %d seconds "
 284                                         "of connection errors.\n",
 285                                         sc->name, (int)dist);
 286                 }
 287         }
 288         return -ERRNO_TO_PARA_ERROR(ret);
 289 }
 290
 291 static void udp_send_fec(struct sender_client *sc, char *buf, size_t len)
 292 {
 293         int ret;
 294
 295         if (sender_status == SENDER_off)
 296                 return;
 297         if (len == 0)
 298                 return;
 299         ret = udp_check_socket_state(sc);
 300         if (ret < 0)
 301                 goto fail;
 302         ret = xwrite(sc->fd, buf, len);
 303         if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
 304                 /*
 305                  * Happens if meanwhile an ICMP Destination / Port Unreachable
 306                  * has arrived. Ignore, persistent errors will be caught above.
 307                  */
 308                 ret = 0;
 309         }
 310         if (ret < 0)
 311                 goto fail;
 312         return;
 313 fail:
 314         udp_delete_target(sc, para_strerror(-ret));
 315 }
 316
 317 static int udp_com_add(struct sender_command_data *scd)
 318 {
 319         int ret;
 320         struct udp_target *ut;
 321         struct sender_client *sc = udp_lookup_target(scd);
 322
 323         if (sc) {
 324                 PARA_NOTICE_LOG("target %s already exists - not adding it\n",
 325                                 sc->name);
 326                 return -E_TARGET_EXISTS;
 327         }
 328         ut = para_calloc(sizeof(*ut));
 329         sc = para_calloc(sizeof(*sc));
 330         ut->fcp.slices_per_group      = scd->slices_per_group;
 331         ut->fcp.data_slices_per_group = scd->data_slices_per_group;
 332         ut->fcp.init_fec              = udp_init_fec;
 333         ut->fcp.send_fec              = udp_send_fec;
 334         ut->fcp.need_periodic_header  = true;
 335
 336         sc->private_data = ut;
 337         sc->fd = -1;
 338         ret = para_connect_simple(IPPROTO_UDP, scd->host, scd->port);
 339         if (ret < 0)
 340                 goto err;
 341         sc->fd = ret;
 342
 343         ret = mcast_sender_setup(sc);
 344         if (ret < 0)
 345                 goto err;
 346         ret = mark_fd_nonblocking(sc->fd);
 347         if (ret < 0)
 348                 goto err;
 349         sc->name = para_strdup(remote_name(sc->fd));
 350         PARA_INFO_LOG("adding to target list (%s)\n", sc->name);
 351         ut->fc = vss_add_fec_client(sc, &ut->fcp);
 352         para_list_add(&sc->node, &targets);
 353         add_close_on_fork_list(sc->fd);
 354         return 1;
 355 err:
 356         if (sc->fd >= 0)
 357                 close(sc->fd);
 358         PARA_NOTICE_LOG("failed to set up %s:%d (%s)- not adding it\n",
 359                         scd->host, scd->port, para_strerror(-ret));
 360         free(sc);
 361         free(ut);
 362         return ret;
 363 }
 364
 365 static char *udp_status(void)
 366 {
 367         struct sender_client *sc;
 368         char *ret, *tgts = NULL;
 369
 370         list_for_each_entry(sc, &targets, node) {
 371                 struct udp_target *ut = sc->private_data;
 372                 char *tmp = make_message("%s%s/%u:%u ",
 373                         tgts ? : "", sc->name,
 374                         ut->fcp.data_slices_per_group,
 375                         ut->fcp.slices_per_group
 376                 );
 377                 free(tgts);
 378                 tgts = tmp;
 379         }
 380         ret = make_message(
 381                 "status: %s\n"
 382                 "port: %s\n"
 383                 "targets: %s\n",
 384                 (sender_status == SENDER_on)? "on" : "off",
 385                 stringify_port(OPT_UINT32_VAL(UDP_DEFAULT_PORT), "udp"),
 386                 tgts? tgts : "(none)"
 387         );
 388         free(tgts);
 389         return ret;
 390 }
 391
 392 static void udp_init_target_list(void)
 393 {
 394         struct sender_command_data scd;
 395         int i;
 396
 397         INIT_LIST_HEAD(&targets);
 398         for (i = 0; i < OPT_GIVEN(UDP_TARGET); i++) {
 399                 const char *arg = lls_string_val(i, OPT_RESULT(UDP_TARGET));
 400                 if (udp_resolve_target(arg, &scd) < 0)
 401                         PARA_CRIT_LOG("not adding requested target '%s'\n",
 402                                         arg);
 403                 else
 404                         udp_com_add(&scd);
 405         }
 406 }
 407
 408 static char *udp_help(void)
 409 {
 410         return make_message(
 411                 "usage: {on|off}\n"
 412                 "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
 413                 "       - k is the number of data slices per FEC group\n"
 414                 "       - n is the total number of slices in a FEC group\n"
 415                 "       - packet_size reduces the slice size below path MTU\n\n"
 416                 "examples: add 224.0.1.38:1500  (IPv4 multicast)\n"
 417                 "          add 224.0.1.38:8080/14:16 (explicit FEC)\n"
 418                 "          add 10.10.1.42       (using default port)\n"
 419                 "          add [FF05::42]:1500  (IPv6 multicast)\n"
 420                 "          add [::1]            (IPv6 localhost/default port)\n"
 421                 "          delete myhost.net    (host with port wildcard)\n"
 422                 "          delete 10.1.2.3:456  (IPv4 with explicit port)\n"
 423                 "          delete [badc0de::1]  (IPv6 with port wildcard)\n"
 424         );
 425 }
 426
 427 /* Initialize the list of udp targets. */
 428 static void udp_send_init(void)
 429 {
 430         INIT_LIST_HEAD(&targets);
 431         sender_status = SENDER_off;
 432         udp_init_target_list();
 433         if (!OPT_GIVEN(UDP_NO_AUTOSTART))
 434                 sender_status = SENDER_on;
 435         PARA_DEBUG_LOG("udp sender init complete\n");
 436 }
 437
 438 /**
 439  * The UDP sender.
 440  *
 441  * In contrast to the other senders the UDP sender is active in the sense that
 442  * it initiates the network connection according to its list of targets rather
 443  * than passively waiting for clients to connect. Like DCCP streams, UDP
 444  * streams are always sent FEC-encoded. The UDP sender is the only sender which
 445  * supports IP multicasting.
 446  */
 447 const struct sender udp_sender = {
 448         .name = "udp",
 449         .init = udp_send_init,
 450         .shutdown = udp_shutdown,
 451         .shutdown_clients = udp_shutdown_targets,
 452         .resolve_target = udp_resolve_target,
 453         .client_cmds = {
 454                 [SENDER_on] = udp_com_on,
 455                 [SENDER_off] = udp_com_off,
 456                 [SENDER_add] = udp_com_add,
 457                 [SENDER_delete] = udp_com_delete,
 458         },
 459         .help = udp_help,
 460         .status = udp_status,
 461 };