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