udp_send.c

   1 /*
   2  * Copyright (C) 2005-2014 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 <sys/socket.h>
  14 #include <netinet/udp.h>
  15 #include <net/if.h>
  16 #include <arpa/inet.h>
  17 #include <sys/un.h>
  18 #include <netdb.h>
  19
  20 #include "server.cmdline.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 };
  51
  52 static struct list_head targets;
  53 static int sender_status;
  54
  55 static void udp_close_target(struct sender_client *sc)
  56 {
  57         const char *buf;
  58         size_t len = vss_get_fec_eof_packet(&buf);
  59
  60         /*
  61          * Ignore the return value of wirte() since we are closing the target
  62          * anyway. The sole purpose of the "do_nothing" statement is to silence
  63          * gcc.
  64          */
  65         if (write(sc->fd, buf, len))
  66                 do_nothing;
  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         close(sc->fd);
  76         del_close_on_fork_list(sc->fd);
  77         vss_del_fec_client(ut->fc);
  78         list_del(&sc->node);
  79         free(sc->name);
  80         free(sc);
  81         free(ut);
  82 }
  83
  84 /**
  85  * Perform AF-independent multicast sender setup.
  86  *
  87  * \param sc    The connected sender client.
  88  *
  89  * \return Zero if okay, negative on error.
  90  */
  91 static int mcast_sender_setup(struct sender_client *sc)
  92 {
  93         struct sockaddr_storage ss;
  94         socklen_t sslen = sizeof(ss);
  95         int ttl = conf.udp_ttl_arg, id = 0;
  96         const int on = 1;
  97
  98         if (conf.udp_mcast_iface_given) {
  99                 char *iface = conf.udp_mcast_iface_arg;
 100
 101                 id = if_nametoindex(iface);
 102                 if (id == 0)
 103                         PARA_WARNING_LOG("could not resolve interface '%s', "
 104                                         "using default", iface);
 105         }
 106
 107         if (getpeername(sc->fd, (struct sockaddr *)&ss, &sslen) < 0)
 108                 goto err;
 109         assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
 110
 111         /* RFC 3493, 5.2: -1 means 'use kernel default' */
 112         if (ttl < 0 || ttl > 255)
 113                 ttl = -1;
 114
 115         switch (ss.ss_family) {
 116         case AF_INET:
 117                 if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
 118                         return 0;
 119                 if (id != 0) {
 120 #ifdef HAVE_IP_MREQN
 121                         struct ip_mreqn mn;
 122
 123                         memset(&mn, 0, sizeof(mn));
 124                         mn.imr_ifindex = id;
 125                         if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_IF, &mn, sizeof(mn)) < 0)
 126                                 goto err;
 127 #else
 128                         PARA_ERROR_LOG("No support for setting outgoing IPv4 mcast interface.");
 129 #endif
 130                 }
 131                 /*
 132                  * Enable receiving multicast messages generated on the local host
 133                  * At least on Linux, this is enabled by default.
 134                  */
 135                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 136                         break;
 137
 138                 /* Default: use local subnet (do not flood out into the WAN) */
 139                 if (ttl == -1)
 140                         ttl = 1;
 141                 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
 142                         break;
 143                 return 0;
 144         case AF_INET6:
 145                 if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
 146                         return 0;
 147                 if (id != 0 &&
 148                     setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &id, sizeof(id)) < 0)
 149                         break;
 150                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
 151                         break;
 152                 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
 153                         break;
 154                 return 0;
 155         }
 156 err:
 157         return -ERRNO_TO_PARA_ERROR(errno);
 158 }
 159
 160 static void udp_init_session(struct sender_client *sc)
 161 {
 162         PARA_NOTICE_LOG("sending to udp %s\n", sc->name);
 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 int udp_resolve_target(const char *url, struct sender_command_data *scd)
 173 {
 174         const char *result;
 175         int ret, port;
 176
 177         ret = parse_fec_url(url, scd);
 178         if (ret)
 179                 return ret;
 180         port = scd->port > 0 ? scd->port : conf.udp_default_port_arg;
 181
 182         ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
 183         if (ret < 0)
 184                 return ret;
 185
 186         result = remote_name(ret);
 187         close(ret);
 188
 189         if (!parse_url(result, scd->host, sizeof(scd->host), &scd->port))
 190                 return -E_ADDRESS_LOOKUP;
 191         return 1;
 192 }
 193
 194 static int udp_com_on(__a_unused struct sender_command_data *scd)
 195 {
 196         sender_status = SENDER_ON;
 197         return 1;
 198 }
 199
 200 static int udp_com_off(__a_unused struct sender_command_data *scd)
 201 {
 202         udp_shutdown_targets();
 203         sender_status = SENDER_OFF;
 204         return 1;
 205 }
 206
 207 static struct sender_client *udp_lookup_target(struct sender_command_data *scd)
 208 {
 209         struct sender_client *sc, *tmp;
 210         char host[MAX_HOSTLEN];
 211         int32_t port;
 212
 213         list_for_each_entry_safe(sc, tmp, &targets, node) {
 214                 parse_url(sc->name, host, sizeof(host), &port);
 215
 216                 /* Unspecified port means wildcard port match */
 217                 if (scd->port > 0 && scd->port != port)
 218                         continue;
 219                 if (strcmp(host, scd->host))
 220                         continue;
 221                 return sc;
 222         }
 223         return NULL;
 224 }
 225
 226 static int udp_com_delete(struct sender_command_data *scd)
 227 {
 228         struct sender_client *sc = udp_lookup_target(scd);
 229
 230         if (sc) {
 231                 udp_delete_target(sc, "com_delete");
 232                 return 1;
 233         }
 234         PARA_NOTICE_LOG("not deleting non-existing target '%s'\n", scd->host);
 235         return -E_TARGET_NOT_FOUND;
 236 }
 237
 238 /** Initialize UDP session and set maximum payload size. */
 239 static int udp_init_fec(struct sender_client *sc)
 240 {
 241         int mps;
 242
 243         udp_init_session(sc);
 244         mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
 245         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 246         return mps;
 247 }
 248
 249 /** Check and clear socket error if any. */
 250 static int udp_check_socket_state(struct sender_client *sc)
 251 {
 252         struct udp_target *ut = sc->private_data;
 253         int ret;
 254         socklen_t errlen = sizeof(ret);
 255
 256         if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
 257                 PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
 258                 return 0;
 259         } else if (ret == 0) {
 260                 return 0;
 261         } else if (ret == ECONNREFUSED) {
 262                 time_t dist = now->tv_sec - ut->last_unreachable;
 263
 264                 if (dist <= UDP_MAX_UNREACHABLE_TIME) {
 265                         return 0;
 266                 } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
 267                         ut->last_unreachable = now->tv_sec;
 268                         return 0;
 269                 } else {
 270                         /*
 271                          * unreachable_time < dist <= 2 * unreachable_time
 272                          * No errors are allowed during this time window.
 273                          */
 274                         PARA_NOTICE_LOG("Evicting %s after %d seconds "
 275                                         "of connection errors.\n",
 276                                         sc->name, (int)dist);
 277                 }
 278         }
 279         return -ERRNO_TO_PARA_ERROR(ret);
 280 }
 281
 282 static void udp_send_fec(struct sender_client *sc, char *buf, size_t len)
 283 {
 284         int ret;
 285
 286         if (sender_status == SENDER_OFF)
 287                 return;
 288         if (len == 0)
 289                 return;
 290         ret = udp_check_socket_state(sc);
 291         if (ret < 0)
 292                 goto fail;
 293         ret = xwrite(sc->fd, buf, len);
 294         if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
 295                 /*
 296                  * Happens if meanwhile an ICMP Destination / Port Unreachable
 297                  * has arrived. Ignore, persistent errors will be caught above.
 298                  */
 299                 ret = 0;
 300         }
 301         if (ret < 0)
 302                 goto fail;
 303         return;
 304 fail:
 305         udp_delete_target(sc, para_strerror(-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_status(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                 "status: %s\n"
 373                 "port: %s\n"
 374                 "targets: %s\n",
 375                 (sender_status == SENDER_ON)? "on" : "off",
 376                 stringify_port(conf.udp_default_port_arg, "udp"),
 377                 tgts? tgts : "(none)"
 378         );
 379         free(tgts);
 380         return ret;
 381 }
 382
 383 static void udp_init_target_list(void)
 384 {
 385         struct sender_command_data scd;
 386         int i;
 387
 388         INIT_LIST_HEAD(&targets);
 389         for (i = 0; i < conf.udp_target_given; i++) {
 390                 if (udp_resolve_target(conf.udp_target_arg[i], &scd) < 0)
 391                         PARA_CRIT_LOG("not adding requested target '%s'\n",
 392                                         conf.udp_target_arg[i]);
 393                 else
 394                         udp_com_add(&scd);
 395         }
 396 }
 397
 398 static char *udp_help(void)
 399 {
 400         return make_message(
 401                 "usage: {on|off}\n"
 402                 "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
 403                 "       - k is the number of data slices per FEC group\n"
 404                 "       - n is the total number of slices in a FEC group\n"
 405                 "       - packet_size reduces the slice size below path MTU\n\n"
 406                 "examples: add 224.0.1.38:1500  (IPv4 multicast)\n"
 407                 "          add 224.0.1.38:8080/14:16 (explicit FEC)\n"
 408                 "          add 10.10.1.42       (using default port)\n"
 409                 "          add [FF05::42]:1500  (IPv6 multicast)\n"
 410                 "          add [::1]            (IPv6 localhost/default port)\n"
 411                 "          delete myhost.net    (host with port wildcard)\n"
 412                 "          delete 10.1.2.3:456  (IPv4 with explicit port)\n"
 413                 "          delete [badc0de::1]  (IPv6 with port wildcard)\n"
 414         );
 415 }
 416
 417 /**
 418  * The init function of para_server's udp sender.
 419  *
 420  * \param s Pointer to the udp sender struct.
 421  *
 422  * It initializes all function pointers of \a s and the list of udp targets.
 423  */
 424 void udp_send_init(struct sender *s)
 425 {
 426         INIT_LIST_HEAD(&targets);
 427         s->status = udp_status;
 428         s->help = udp_help;
 429         s->send = NULL;
 430         s->pre_select = NULL;
 431         s->post_select = NULL;
 432         s->shutdown_clients = udp_shutdown_targets;
 433         s->resolve_target = udp_resolve_target;
 434         s->client_cmds[SENDER_ON] = udp_com_on;
 435         s->client_cmds[SENDER_OFF] = udp_com_off;
 436         s->client_cmds[SENDER_DENY] = NULL;
 437         s->client_cmds[SENDER_ALLOW] = NULL;
 438         s->client_cmds[SENDER_ADD] = udp_com_add;
 439         s->client_cmds[SENDER_DELETE] = udp_com_delete;
 440         sender_status = SENDER_OFF;
 441         udp_init_target_list();
 442         if (!conf.udp_no_autostart_given)
 443                 sender_status = SENDER_ON;
 444         PARA_DEBUG_LOG("udp sender init complete\n");
 445 }