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_INFO_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         if (!process_is_command_handler())
  76                 PARA_NOTICE_LOG("deleting %s (%s) from list\n", sc->name, msg);
  77         udp_close_target(sc);
  78         /* command handlers already called close_listed_fds() */
  79         if (!process_is_command_handler()) {
  80                 close(sc->fd);
  81                 del_close_on_fork_list(sc->fd);
  82         }
  83         vss_del_fec_client(ut->fc);
  84         list_del(&sc->node);
  85         free(sc->name);
  86         free(sc);
  87         free(ut);
  88 }
  89
  90 /**
  91  * Perform AF-independent multicast sender setup.
  92  *
  93  * \param sc    The connected sender client.
  94  *
  95  * \return Zero if okay, negative on error.
  96  */
  97 static int mcast_sender_setup(struct sender_client *sc)
  98 {
  99         struct sockaddr_storage ss;
 100         socklen_t sslen = sizeof(ss);
 101         int ttl = OPT_INT32_VAL(UDP_TTL), id = 0;
 102         const int on = 1;
 103
 104         if (OPT_GIVEN(UDP_MCAST_IFACE)) {
 105                 const char *iface = OPT_STRING_VAL(UDP_MCAST_IFACE);
 106
 107                 id = if_nametoindex(iface);
 108                 if (id == 0)
 109                         PARA_WARNING_LOG("could not resolve interface '%s', "
 110                                         "using default", iface);
 111         }
 112
 113         if (getpeername(sc->fd, (struct sockaddr *)&ss, &sslen) < 0)
 114                 goto err;
 115         assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
 116
 117         /* RFC 3493, 5.2: -1 means 'use kernel default' */
 118         if (ttl < 0 || ttl > 255)
 119                 ttl = -1;
 120
 121         switch (ss.ss_family) {
 122         case AF_INET:
 123                 if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
 124                         return 0;
 125                 if (id != 0) {
 126 #ifdef HAVE_IP_MREQN
 127                         struct ip_mreqn mn;
 128
 129                         memset(&mn, 0, sizeof(mn));
 130                         mn.imr_ifindex = id;
 131                         if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_IF, &mn, sizeof(mn)) < 0)
 132                                 goto err;
 133 #else
 134                         PARA_ERROR_LOG("No support for setting outgoing IPv4 mcast interface.");
 135 #endif
 136                 }
 137                 /*
 138                  * Enable receiving multicast messages generated on the local host
 139                  * At least on Linux, this is enabled by default.
 140                  */
 141                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 142                         break;
 143
 144                 /* Default: use local subnet (do not flood out into the WAN) */
 145                 if (ttl == -1)
 146                         ttl = 1;
 147                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
 148                         break;
 149                 return 0;
 150         case AF_INET6:
 151                 if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
 152                         return 0;
 153                 if (id != 0 &&
 154                     setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &id, sizeof(id)) < 0)
 155                         break;
 156                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 157                         break;
 158                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
 159                         break;
 160                 return 0;
 161         }
 162 err:
 163         return -ERRNO_TO_PARA_ERROR(errno);
 164 }
 165
 166 static void udp_shutdown_targets(void)
 167 {
 168         struct sender_client *sc, *tmp;
 169         list_for_each_entry_safe(sc, tmp, &targets, node)
 170                 udp_close_target(sc);
 171 }
 172
 173 static void udp_shutdown(void)
 174 {
 175         struct sender_client *sc, *tmp;
 176         list_for_each_entry_safe(sc, tmp, &targets, node)
 177                 udp_delete_target(sc, "shutdown");
 178 }
 179
 180 static int udp_resolve_target(const char *url, struct sender_command_data *scd)
 181 {
 182         const char *result;
 183         int ret, port;
 184
 185         ret = parse_fec_url(url, scd);
 186         if (ret)
 187                 return ret;
 188         port = scd->port > 0 ? scd->port : OPT_UINT32_VAL(UDP_DEFAULT_PORT);
 189
 190         ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
 191         if (ret < 0)
 192                 return ret;
 193
 194         result = remote_name(ret);
 195         close(ret);
 196
 197         if (!parse_url(result, scd->host, sizeof(scd->host), &scd->port))
 198                 return -E_ADDRESS_LOOKUP;
 199         return 1;
 200 }
 201
 202 static int udp_com_on(__a_unused struct sender_command_data *scd)
 203 {
 204         sender_status = SENDER_on;
 205         return 1;
 206 }
 207
 208 static int udp_com_off(__a_unused struct sender_command_data *scd)
 209 {
 210         udp_shutdown_targets();
 211         sender_status = SENDER_off;
 212         return 1;
 213 }
 214
 215 static struct sender_client *udp_lookup_target(struct sender_command_data *scd)
 216 {
 217         struct sender_client *sc, *tmp;
 218         char host[MAX_HOSTLEN];
 219         int32_t port;
 220
 221         list_for_each_entry_safe(sc, tmp, &targets, node) {
 222                 parse_url(sc->name, host, sizeof(host), &port);
 223
 224                 /* Unspecified port means wildcard port match */
 225                 if (scd->port > 0 && scd->port != port)
 226                         continue;
 227                 if (strcmp(host, scd->host))
 228                         continue;
 229                 return sc;
 230         }
 231         return NULL;
 232 }
 233
 234 static int udp_com_delete(struct sender_command_data *scd)
 235 {
 236         struct sender_client *sc = udp_lookup_target(scd);
 237
 238         if (sc) {
 239                 udp_delete_target(sc, "com_delete");
 240                 return 1;
 241         }
 242         PARA_NOTICE_LOG("not deleting non-existing target '%s'\n", scd->host);
 243         return -E_TARGET_NOT_FOUND;
 244 }
 245
 246 /** Initialize UDP session and set maximum payload size. */
 247 static int udp_init_fec(struct sender_client *sc)
 248 {
 249         struct udp_target *ut = sc->private_data;
 250         int mps;
 251
 252         PARA_INFO_LOG("sending to udp %s\n", sc->name);
 253         ut->sent_fec_eof = false;
 254         mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
 255         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 256         return mps;
 257 }
 258
 259 /** Check and clear socket error if any. */
 260 static int udp_check_socket_state(struct sender_client *sc)
 261 {
 262         struct udp_target *ut = sc->private_data;
 263         int ret;
 264         socklen_t errlen = sizeof(ret);
 265
 266         if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
 267                 PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
 268                 return 0;
 269         } else if (ret == 0) {
 270                 return 0;
 271         } else if (ret == ECONNREFUSED) {
 272                 time_t dist = now->tv_sec - ut->last_unreachable;
 273
 274                 if (dist <= UDP_MAX_UNREACHABLE_TIME) {
 275                         return 0;
 276                 } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
 277                         ut->last_unreachable = now->tv_sec;
 278                         return 0;
 279                 } else {
 280                         /*
 281                          * unreachable_time < dist <= 2 * unreachable_time
 282                          * No errors are allowed during this time window.
 283                          */
 284                         PARA_NOTICE_LOG("Evicting %s after %d seconds "
 285                                         "of connection errors.\n",
 286                                         sc->name, (int)dist);
 287                 }
 288         }
 289         return -ERRNO_TO_PARA_ERROR(ret);
 290 }
 291
 292 static void udp_send_fec(struct sender_client *sc, char *buf, size_t len)
 293 {
 294         int ret;
 295
 296         if (sender_status == SENDER_off)
 297                 return;
 298         if (len == 0)
 299                 return;
 300         ret = udp_check_socket_state(sc);
 301         if (ret < 0)
 302                 goto fail;
 303         ret = xwrite(sc->fd, buf, len);
 304         if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
 305                 /*
 306                  * Happens if meanwhile an ICMP Destination / Port Unreachable
 307                  * has arrived. Ignore, persistent errors will be caught above.
 308                  */
 309                 ret = 0;
 310         }
 311         if (ret < 0)
 312                 goto fail;
 313         return;
 314 fail:
 315         udp_delete_target(sc, para_strerror(-ret));
 316 }
 317
 318 static int udp_com_add(struct sender_command_data *scd)
 319 {
 320         int ret;
 321         struct udp_target *ut;
 322         struct sender_client *sc = udp_lookup_target(scd);
 323
 324         if (sc) {
 325                 PARA_NOTICE_LOG("target %s already exists - not adding it\n",
 326                                 sc->name);
 327                 return -E_TARGET_EXISTS;
 328         }
 329         ut = para_calloc(sizeof(*ut));
 330         sc = para_calloc(sizeof(*sc));
 331         ut->fcp.slices_per_group      = scd->slices_per_group;
 332         ut->fcp.data_slices_per_group = scd->data_slices_per_group;
 333         ut->fcp.init_fec              = udp_init_fec;
 334         ut->fcp.send_fec              = udp_send_fec;
 335         ut->fcp.need_periodic_header  = true;
 336
 337         sc->private_data = ut;
 338         sc->fd = -1;
 339         ret = para_connect_simple(IPPROTO_UDP, scd->host, scd->port);
 340         if (ret < 0)
 341                 goto err;
 342         sc->fd = ret;
 343
 344         ret = mcast_sender_setup(sc);
 345         if (ret < 0)
 346                 goto err;
 347         ret = mark_fd_nonblocking(sc->fd);
 348         if (ret < 0)
 349                 goto err;
 350         sc->name = para_strdup(remote_name(sc->fd));
 351         PARA_INFO_LOG("adding to target list (%s)\n", sc->name);
 352         ut->fc = vss_add_fec_client(sc, &ut->fcp);
 353         para_list_add(&sc->node, &targets);
 354         add_close_on_fork_list(sc->fd);
 355         return 1;
 356 err:
 357         if (sc->fd >= 0)
 358                 close(sc->fd);
 359         PARA_NOTICE_LOG("failed to set up %s:%d (%s)- not adding it\n",
 360                         scd->host, scd->port, para_strerror(-ret));
 361         free(sc);
 362         free(ut);
 363         return ret;
 364 }
 365
 366 static char *udp_status(void)
 367 {
 368         struct sender_client *sc;
 369         char *ret, *tgts = NULL;
 370
 371         list_for_each_entry(sc, &targets, node) {
 372                 struct udp_target *ut = sc->private_data;
 373                 char *tmp = make_message("%s%s/%u:%u ",
 374                         tgts ? : "", sc->name,
 375                         ut->fcp.data_slices_per_group,
 376                         ut->fcp.slices_per_group
 377                 );
 378                 free(tgts);
 379                 tgts = tmp;
 380         }
 381         ret = make_message(
 382                 "status: %s\n"
 383                 "port: %s\n"
 384                 "targets: %s\n",
 385                 (sender_status == SENDER_on)? "on" : "off",
 386                 stringify_port(OPT_UINT32_VAL(UDP_DEFAULT_PORT), "udp"),
 387                 tgts? tgts : "(none)"
 388         );
 389         free(tgts);
 390         return ret;
 391 }
 392
 393 static void udp_init_target_list(void)
 394 {
 395         struct sender_command_data scd;
 396         int i;
 397
 398         init_list_head(&targets);
 399         for (i = 0; i < OPT_GIVEN(UDP_TARGET); i++) {
 400                 const char *arg = lls_string_val(i, OPT_RESULT(UDP_TARGET));
 401                 if (udp_resolve_target(arg, &scd) < 0)
 402                         PARA_CRIT_LOG("not adding requested target '%s'\n",
 403                                         arg);
 404                 else
 405                         udp_com_add(&scd);
 406         }
 407 }
 408
 409 static char *udp_help(void)
 410 {
 411         return make_message(
 412                 "usage: {on|off}\n"
 413                 "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
 414                 "       - k is the number of data slices per FEC group\n"
 415                 "       - n is the total number of slices in a FEC group\n"
 416                 "       - packet_size reduces the slice size below path MTU\n\n"
 417                 "examples: add 224.0.1.38:1500  (IPv4 multicast)\n"
 418                 "          add 224.0.1.38:8080/14:16 (explicit FEC)\n"
 419                 "          add 10.10.1.42       (using default port)\n"
 420                 "          add [FF05::42]:1500  (IPv6 multicast)\n"
 421                 "          add [::1]            (IPv6 localhost/default port)\n"
 422                 "          delete myhost.net    (host with port wildcard)\n"
 423                 "          delete 10.1.2.3:456  (IPv4 with explicit port)\n"
 424                 "          delete [badc0de::1]  (IPv6 with port wildcard)\n"
 425         );
 426 }
 427
 428 /* Initialize the list of udp targets. */
 429 static void udp_send_init(void)
 430 {
 431         init_list_head(&targets);
 432         sender_status = SENDER_off;
 433         udp_init_target_list();
 434         if (!OPT_GIVEN(UDP_NO_AUTOSTART))
 435                 sender_status = SENDER_on;
 436         PARA_DEBUG_LOG("udp sender init complete\n");
 437 }
 438
 439 /**
 440  * The UDP sender.
 441  *
 442  * In contrast to the other senders the UDP sender is active in the sense that
 443  * it initiates the network connection according to its list of targets rather
 444  * than passively waiting for clients to connect. Like DCCP streams, UDP
 445  * streams are always sent FEC-encoded. The UDP sender is the only sender which
 446  * supports IP multicasting.
 447  */
 448 const struct sender udp_sender = {
 449         .name = "udp",
 450         .init = udp_send_init,
 451         .shutdown = udp_shutdown,
 452         .shutdown_clients = udp_shutdown_targets,
 453         .resolve_target = udp_resolve_target,
 454         .client_cmds = {
 455                 [SENDER_on] = udp_com_on,
 456                 [SENDER_off] = udp_com_off,
 457                 [SENDER_add] = udp_com_add,
 458                 [SENDER_delete] = udp_com_delete,
 459         },
 460         .help = udp_help,
 461         .status = udp_status,
 462 };