udp_send.c

   1 /*
   2  * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
   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
  10 #include <regex.h>
  11 #include <sys/time.h>
  12 #include <sys/socket.h>
  13 #include <netinet/udp.h>
  14 #include <net/if.h>
  15 #include <osl.h>
  16 #include <stdbool.h>
  17
  18 #include "server.cmdline.h"
  19 #include "para.h"
  20 #include "error.h"
  21 #include "string.h"
  22 #include "afh.h"
  23 #include "afs.h"
  24 #include "server.h"
  25 #include "list.h"
  26 #include "send.h"
  27 #include "vss.h"
  28 #include "portable_io.h"
  29 #include "net.h"
  30 #include "fd.h"
  31 #include "sched.h"
  32 #include "close_on_fork.h"
  33
  34 /**
  35  * Time window during which ICMP Destination/Port Unreachable messages are
  36  * ignored, covering transient receiver problems such as restarting the
  37  * client, rebooting, reconfiguration, or handover.
  38  */
  39 #define UDP_MAX_UNREACHABLE_TIME 30
  40
  41 /** Describes one entry in the list of targets for the udp sender. */
  42 struct udp_target {
  43         /** Track time (seconds) of last ICMP Port Unreachable error */
  44         time_t last_unreachable;
  45         /** The opaque structure returned by vss_add_fec_client(). */
  46         struct fec_client *fc;
  47         /** The FEC parameters for this target. */
  48         struct fec_client_parms fcp;
  49 };
  50
  51 static struct list_head targets;
  52 static int sender_status;
  53
  54 static void udp_close_target(struct sender_client *sc)
  55 {
  56         const char *buf;
  57         size_t len = vss_get_fec_eof_packet(&buf);
  58
  59         /*
  60          * Ignore the return value of wirte() since we are closing the target
  61          * anyway. The sole purpose of the "do_nothing" statement is to silence
  62          * gcc.
  63          */
  64         if (write(sc->fd, buf, len))
  65                 do_nothing;
  66 }
  67
  68 static void udp_delete_target(struct sender_client *sc, const char *msg)
  69 {
  70         struct udp_target *ut = sc->private_data;
  71
  72         PARA_NOTICE_LOG("deleting %s (%s) from list\n", sc->name, msg);
  73         udp_close_target(sc);
  74         close(sc->fd);
  75         del_close_on_fork_list(sc->fd);
  76         vss_del_fec_client(ut->fc);
  77         list_del(&sc->node);
  78         free(sc->name);
  79         free(sc);
  80         free(ut);
  81 }
  82
  83 /**
  84  * Perform AF-independent multicast sender setup.
  85  *
  86  * \param sc    The connected sender client.
  87  *
  88  * \return Zero if okay, negative on error.
  89  */
  90 static int mcast_sender_setup(struct sender_client *sc)
  91 {
  92         struct sockaddr_storage ss;
  93         socklen_t sslen = sizeof(ss);
  94         int ttl = conf.udp_ttl_arg, id = 0;
  95         const int on = 1;
  96
  97         if (conf.udp_mcast_iface_given) {
  98                 char *iface = conf.udp_mcast_iface_arg;
  99
 100                 id = if_nametoindex(iface);
 101                 if (id == 0)
 102                         PARA_WARNING_LOG("could not resolve interface '%s', "
 103                                         "using default", iface);
 104         }
 105
 106         if (getpeername(sc->fd, (struct sockaddr *)&ss, &sslen) < 0)
 107                 goto err;
 108         assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
 109
 110         /* RFC 3493, 5.2: -1 means 'use kernel default' */
 111         if (ttl < 0 || ttl > 255)
 112                 ttl = -1;
 113
 114         switch (ss.ss_family) {
 115         case AF_INET:
 116                 if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
 117                         return 0;
 118                 if (id != 0) {
 119 #ifdef HAVE_IP_MREQN
 120                         struct ip_mreqn mn;
 121
 122                         memset(&mn, 0, sizeof(mn));
 123                         mn.imr_ifindex = id;
 124                         if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_IF, &mn, sizeof(mn)) < 0)
 125                                 goto err;
 126 #else
 127                         PARA_ERROR_LOG("No support for setting outgoing IPv4 mcast interface.");
 128 #endif
 129                 }
 130                 /*
 131                  * Enable receiving multicast messages generated on the local host
 132                  * At least on Linux, this is enabled by default.
 133                  */
 134                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 135                         break;
 136
 137                 /* Default: use local subnet (do not flood out into the WAN) */
 138                 if (ttl == -1)
 139                         ttl = 1;
 140                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
 141                         break;
 142                 return 0;
 143         case AF_INET6:
 144                 if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
 145                         return 0;
 146                 if (id != 0 &&
 147                     setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &id, sizeof(id)) < 0)
 148                         break;
 149                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 150                         break;
 151                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
 152                         break;
 153                 return 0;
 154         }
 155 err:
 156         return -ERRNO_TO_PARA_ERROR(errno);
 157 }
 158
 159 static void udp_init_session(struct sender_client *sc)
 160 {
 161         PARA_NOTICE_LOG("sending to udp %s\n", sc->name);
 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 : conf.udp_default_port_arg;
 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         int mps;
 241
 242         udp_init_session(sc);
 243         mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
 244         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 245         return mps;
 246 }
 247
 248 /** Check and clear socket error if any. */
 249 static int udp_check_socket_state(struct sender_client *sc)
 250 {
 251         struct udp_target *ut = sc->private_data;
 252         int ret;
 253         socklen_t errlen = sizeof(ret);
 254
 255         if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
 256                 PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
 257                 return 0;
 258         } else if (ret == 0) {
 259                 return 0;
 260         } else if (ret == ECONNREFUSED) {
 261                 time_t dist = now->tv_sec - ut->last_unreachable;
 262
 263                 if (dist <= UDP_MAX_UNREACHABLE_TIME) {
 264                         return 0;
 265                 } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
 266                         ut->last_unreachable = now->tv_sec;
 267                         return 0;
 268                 } else {
 269                         /*
 270                          * unreachable_time < dist <= 2 * unreachable_time
 271                          * No errors are allowed during this time window.
 272                          */
 273                         PARA_NOTICE_LOG("Evicting %s after %d seconds "
 274                                         "of connection errors.\n",
 275                                         sc->name, (int)dist);
 276                 }
 277         }
 278         return -ERRNO_TO_PARA_ERROR(ret);
 279 }
 280
 281 static int udp_send_fec(struct sender_client *sc, char *buf, size_t len)
 282 {
 283         int ret;
 284
 285         if (sender_status == SENDER_OFF)
 286                 return 0;
 287         if (len == 0)
 288                 return 0;
 289         ret = udp_check_socket_state(sc);
 290         if (ret < 0)
 291                 goto fail;
 292         ret = write_nonblock(sc->fd, buf, len);
 293         if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
 294                 /*
 295                  * Happens if meanwhile an ICMP Destination / Port Unreachable
 296                  * has arrived. Ignore, persistent errors will be caught above.
 297                  */
 298                 ret = 0;
 299         }
 300         if (ret < 0)
 301                 goto fail;
 302         return 1;
 303 fail:
 304         udp_delete_target(sc, para_strerror(-ret));
 305         return ret;
 306 }
 307
 308 static int udp_com_add(struct sender_command_data *scd)
 309 {
 310         int ret;
 311         struct udp_target *ut;
 312         struct sender_client *sc = udp_lookup_target(scd);
 313
 314         if (sc) {
 315                 PARA_NOTICE_LOG("target %s already exists - not adding it\n",
 316                                 sc->name);
 317                 return -E_TARGET_EXISTS;
 318         }
 319         ut = para_calloc(sizeof(*ut));
 320         sc = para_calloc(sizeof(*sc));
 321         ut->fcp.slices_per_group      = scd->slices_per_group;
 322         ut->fcp.data_slices_per_group = scd->data_slices_per_group;
 323         ut->fcp.init_fec              = udp_init_fec;
 324         ut->fcp.send_fec              = udp_send_fec;
 325         ut->fcp.need_periodic_header  = true;
 326
 327         sc->private_data = ut;
 328         sc->fd = -1;
 329         ret = para_connect_simple(IPPROTO_UDP, scd->host, scd->port);
 330         if (ret < 0)
 331                 goto err;
 332         sc->fd = ret;
 333
 334         ret = mcast_sender_setup(sc);
 335         if (ret < 0)
 336                 goto err;
 337         ret = mark_fd_nonblocking(sc->fd);
 338         if (ret < 0)
 339                 goto err;
 340         sc->name = para_strdup(remote_name(sc->fd));
 341         PARA_INFO_LOG("adding to target list (%s)\n", sc->name);
 342         ut->fc = vss_add_fec_client(sc, &ut->fcp);
 343         para_list_add(&sc->node, &targets);
 344         add_close_on_fork_list(sc->fd);
 345         return 1;
 346 err:
 347         if (sc->fd >= 0)
 348                 close(sc->fd);
 349         PARA_NOTICE_LOG("failed to set up %s:%d (%s)- not adding it\n",
 350                         scd->host, scd->port, para_strerror(-ret));
 351         free(sc);
 352         free(ut);
 353         return ret;
 354 }
 355
 356 static char *udp_info(void)
 357 {
 358         struct sender_client *sc;
 359         char *ret, *tgts = NULL;
 360
 361         list_for_each_entry(sc, &targets, node) {
 362                 struct udp_target *ut = sc->private_data;
 363                 char *tmp = make_message("%s%s/%u:%u ",
 364                         tgts ? : "", sc->name,
 365                         ut->fcp.data_slices_per_group,
 366                         ut->fcp.slices_per_group
 367                 );
 368                 free(tgts);
 369                 tgts = tmp;
 370         }
 371         ret = make_message(
 372                 "udp sender:\n"
 373                 "\tstatus: %s\n"
 374                 "\tport: %s\n"
 375                 "\ttargets: %s\n",
 376                 (sender_status == SENDER_ON)? "on" : "off",
 377                 stringify_port(conf.udp_default_port_arg, "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 < conf.udp_target_given; i++) {
 391                 if (udp_resolve_target(conf.udp_target_arg[i], &scd) < 0)
 392                         PARA_CRIT_LOG("not adding requested target '%s'\n",
 393                                         conf.udp_target_arg[i]);
 394                 else
 395                         udp_com_add(&scd);
 396         }
 397 }
 398
 399 static char *udp_help(void)
 400 {
 401         return make_message(
 402                 "usage: {on|off}\n"
 403                 "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
 404                 "       - k is the number of data slices per FEC group\n"
 405                 "       - n is the total number of slices in a FEC group\n"
 406                 "       - packet_size reduces the slice size below path MTU\n\n"
 407                 "examples: add 224.0.1.38:1500  (IPv4 multicast)\n"
 408                 "          add 224.0.1.38:8080/14:16 (explicit FEC)\n"
 409                 "          add 10.10.1.42       (using default port)\n"
 410                 "          add [FF05::42]:1500  (IPv6 multicast)\n"
 411                 "          add [::1]            (IPv6 localhost/default port)\n"
 412                 "          delete myhost.net    (host with port wildcard)\n"
 413                 "          delete 10.1.2.3:456  (IPv4 with explicit port)\n"
 414                 "          delete [badc0de::1]  (IPv6 with port wildcard)\n"
 415         );
 416 }
 417
 418 /**
 419  * The init function of para_server's udp sender.
 420  *
 421  * \param s Pointer to the udp sender struct.
 422  *
 423  * It initializes all function pointers of \a s and the list of udp targets.
 424  */
 425 void udp_send_init(struct sender *s)
 426 {
 427         INIT_LIST_HEAD(&targets);
 428         s->info = udp_info;
 429         s->help = udp_help;
 430         s->send = NULL;
 431         s->pre_select = NULL;
 432         s->post_select = NULL;
 433         s->shutdown_clients = udp_shutdown_targets;
 434         s->resolve_target = udp_resolve_target;
 435         s->client_cmds[SENDER_ON] = udp_com_on;
 436         s->client_cmds[SENDER_OFF] = udp_com_off;
 437         s->client_cmds[SENDER_DENY] = NULL;
 438         s->client_cmds[SENDER_ALLOW] = NULL;
 439         s->client_cmds[SENDER_ADD] = udp_com_add;
 440         s->client_cmds[SENDER_DELETE] = udp_com_delete;
 441         sender_status = SENDER_OFF;
 442         udp_init_target_list();
 443         if (!conf.udp_no_autostart_given)
 444                 sender_status = SENDER_ON;
 445         PARA_DEBUG_LOG("udp sender init complete\n");
 446 }