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