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         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 = OPT_INT32_VAL(UDP_TTL), id = 0;
  96         const int on = 1;
  97
  98         if (OPT_GIVEN(UDP_MCAST_IFACE)) {
  99                 const char *iface = OPT_STRING_VAL(UDP_MCAST_IFACE);
 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_shutdown_targets(void)
 161 {
 162         struct sender_client *sc, *tmp;
 163         list_for_each_entry_safe(sc, tmp, &targets, node)
 164                 udp_close_target(sc);
 165 }
 166
 167 static int udp_resolve_target(const char *url, struct sender_command_data *scd)
 168 {
 169         const char *result;
 170         int ret, port;
 171
 172         ret = parse_fec_url(url, scd);
 173         if (ret)
 174                 return ret;
 175         port = scd->port > 0 ? scd->port : OPT_UINT32_VAL(UDP_DEFAULT_PORT);
 176
 177         ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
 178         if (ret < 0)
 179                 return ret;
 180
 181         result = remote_name(ret);
 182         close(ret);
 183
 184         if (!parse_url(result, scd->host, sizeof(scd->host), &scd->port))
 185                 return -E_ADDRESS_LOOKUP;
 186         return 1;
 187 }
 188
 189 static int udp_com_on(__a_unused struct sender_command_data *scd)
 190 {
 191         sender_status = SENDER_on;
 192         return 1;
 193 }
 194
 195 static int udp_com_off(__a_unused struct sender_command_data *scd)
 196 {
 197         udp_shutdown_targets();
 198         sender_status = SENDER_off;
 199         return 1;
 200 }
 201
 202 static struct sender_client *udp_lookup_target(struct sender_command_data *scd)
 203 {
 204         struct sender_client *sc, *tmp;
 205         char host[MAX_HOSTLEN];
 206         int32_t port;
 207
 208         list_for_each_entry_safe(sc, tmp, &targets, node) {
 209                 parse_url(sc->name, host, sizeof(host), &port);
 210
 211                 /* Unspecified port means wildcard port match */
 212                 if (scd->port > 0 && scd->port != port)
 213                         continue;
 214                 if (strcmp(host, scd->host))
 215                         continue;
 216                 return sc;
 217         }
 218         return NULL;
 219 }
 220
 221 static int udp_com_delete(struct sender_command_data *scd)
 222 {
 223         struct sender_client *sc = udp_lookup_target(scd);
 224
 225         if (sc) {
 226                 udp_delete_target(sc, "com_delete");
 227                 return 1;
 228         }
 229         PARA_NOTICE_LOG("not deleting non-existing target '%s'\n", scd->host);
 230         return -E_TARGET_NOT_FOUND;
 231 }
 232
 233 /** Initialize UDP session and set maximum payload size. */
 234 static int udp_init_fec(struct sender_client *sc)
 235 {
 236         struct udp_target *ut = sc->private_data;
 237         int mps;
 238
 239         PARA_NOTICE_LOG("sending to udp %s\n", sc->name);
 240         ut->sent_fec_eof = false;
 241         mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
 242         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 243         return mps;
 244 }
 245
 246 /** Check and clear socket error if any. */
 247 static int udp_check_socket_state(struct sender_client *sc)
 248 {
 249         struct udp_target *ut = sc->private_data;
 250         int ret;
 251         socklen_t errlen = sizeof(ret);
 252
 253         if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
 254                 PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
 255                 return 0;
 256         } else if (ret == 0) {
 257                 return 0;
 258         } else if (ret == ECONNREFUSED) {
 259                 time_t dist = now->tv_sec - ut->last_unreachable;
 260
 261                 if (dist <= UDP_MAX_UNREACHABLE_TIME) {
 262                         return 0;
 263                 } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
 264                         ut->last_unreachable = now->tv_sec;
 265                         return 0;
 266                 } else {
 267                         /*
 268                          * unreachable_time < dist <= 2 * unreachable_time
 269                          * No errors are allowed during this time window.
 270                          */
 271                         PARA_NOTICE_LOG("Evicting %s after %d seconds "
 272                                         "of connection errors.\n",
 273                                         sc->name, (int)dist);
 274                 }
 275         }
 276         return -ERRNO_TO_PARA_ERROR(ret);
 277 }
 278
 279 static void udp_send_fec(struct sender_client *sc, char *buf, size_t len)
 280 {
 281         int ret;
 282
 283         if (sender_status == SENDER_off)
 284                 return;
 285         if (len == 0)
 286                 return;
 287         ret = udp_check_socket_state(sc);
 288         if (ret < 0)
 289                 goto fail;
 290         ret = xwrite(sc->fd, buf, len);
 291         if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
 292                 /*
 293                  * Happens if meanwhile an ICMP Destination / Port Unreachable
 294                  * has arrived. Ignore, persistent errors will be caught above.
 295                  */
 296                 ret = 0;
 297         }
 298         if (ret < 0)
 299                 goto fail;
 300         return;
 301 fail:
 302         udp_delete_target(sc, para_strerror(-ret));
 303 }
 304
 305 static int udp_com_add(struct sender_command_data *scd)
 306 {
 307         int ret;
 308         struct udp_target *ut;
 309         struct sender_client *sc = udp_lookup_target(scd);
 310
 311         if (sc) {
 312                 PARA_NOTICE_LOG("target %s already exists - not adding it\n",
 313                                 sc->name);
 314                 return -E_TARGET_EXISTS;
 315         }
 316         ut = para_calloc(sizeof(*ut));
 317         sc = para_calloc(sizeof(*sc));
 318         ut->fcp.slices_per_group      = scd->slices_per_group;
 319         ut->fcp.data_slices_per_group = scd->data_slices_per_group;
 320         ut->fcp.init_fec              = udp_init_fec;
 321         ut->fcp.send_fec              = udp_send_fec;
 322         ut->fcp.need_periodic_header  = true;
 323
 324         sc->private_data = ut;
 325         sc->fd = -1;
 326         ret = para_connect_simple(IPPROTO_UDP, scd->host, scd->port);
 327         if (ret < 0)
 328                 goto err;
 329         sc->fd = ret;
 330
 331         ret = mcast_sender_setup(sc);
 332         if (ret < 0)
 333                 goto err;
 334         ret = mark_fd_nonblocking(sc->fd);
 335         if (ret < 0)
 336                 goto err;
 337         sc->name = para_strdup(remote_name(sc->fd));
 338         PARA_INFO_LOG("adding to target list (%s)\n", sc->name);
 339         ut->fc = vss_add_fec_client(sc, &ut->fcp);
 340         para_list_add(&sc->node, &targets);
 341         add_close_on_fork_list(sc->fd);
 342         return 1;
 343 err:
 344         if (sc->fd >= 0)
 345                 close(sc->fd);
 346         PARA_NOTICE_LOG("failed to set up %s:%d (%s)- not adding it\n",
 347                         scd->host, scd->port, para_strerror(-ret));
 348         free(sc);
 349         free(ut);
 350         return ret;
 351 }
 352
 353 static char *udp_status(void)
 354 {
 355         struct sender_client *sc;
 356         char *ret, *tgts = NULL;
 357
 358         list_for_each_entry(sc, &targets, node) {
 359                 struct udp_target *ut = sc->private_data;
 360                 char *tmp = make_message("%s%s/%u:%u ",
 361                         tgts ? : "", sc->name,
 362                         ut->fcp.data_slices_per_group,
 363                         ut->fcp.slices_per_group
 364                 );
 365                 free(tgts);
 366                 tgts = tmp;
 367         }
 368         ret = make_message(
 369                 "status: %s\n"
 370                 "port: %s\n"
 371                 "targets: %s\n",
 372                 (sender_status == SENDER_on)? "on" : "off",
 373                 stringify_port(OPT_UINT32_VAL(UDP_DEFAULT_PORT), "udp"),
 374                 tgts? tgts : "(none)"
 375         );
 376         free(tgts);
 377         return ret;
 378 }
 379
 380 static void udp_init_target_list(void)
 381 {
 382         struct sender_command_data scd;
 383         int i;
 384
 385         INIT_LIST_HEAD(&targets);
 386         for (i = 0; i < OPT_GIVEN(UDP_TARGET); i++) {
 387                 const char *arg = lls_string_val(i, OPT_RESULT(UDP_TARGET));
 388                 if (udp_resolve_target(arg, &scd) < 0)
 389                         PARA_CRIT_LOG("not adding requested target '%s'\n",
 390                                         arg);
 391                 else
 392                         udp_com_add(&scd);
 393         }
 394 }
 395
 396 static char *udp_help(void)
 397 {
 398         return make_message(
 399                 "usage: {on|off}\n"
 400                 "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
 401                 "       - k is the number of data slices per FEC group\n"
 402                 "       - n is the total number of slices in a FEC group\n"
 403                 "       - packet_size reduces the slice size below path MTU\n\n"
 404                 "examples: add 224.0.1.38:1500  (IPv4 multicast)\n"
 405                 "          add 224.0.1.38:8080/14:16 (explicit FEC)\n"
 406                 "          add 10.10.1.42       (using default port)\n"
 407                 "          add [FF05::42]:1500  (IPv6 multicast)\n"
 408                 "          add [::1]            (IPv6 localhost/default port)\n"
 409                 "          delete myhost.net    (host with port wildcard)\n"
 410                 "          delete 10.1.2.3:456  (IPv4 with explicit port)\n"
 411                 "          delete [badc0de::1]  (IPv6 with port wildcard)\n"
 412         );
 413 }
 414
 415 /**
 416  * The init function of para_server's udp sender.
 417  *
 418  * \param s Pointer to the udp sender struct.
 419  *
 420  * It initializes all function pointers of \a s and the list of udp targets.
 421  */
 422 void udp_send_init(struct sender *s)
 423 {
 424         INIT_LIST_HEAD(&targets);
 425         s->status = udp_status;
 426         s->help = udp_help;
 427         s->send = NULL;
 428         s->pre_select = NULL;
 429         s->post_select = NULL;
 430         s->shutdown_clients = udp_shutdown_targets;
 431         s->resolve_target = udp_resolve_target;
 432         s->client_cmds[SENDER_on] = udp_com_on;
 433         s->client_cmds[SENDER_off] = udp_com_off;
 434         s->client_cmds[SENDER_deny] = NULL;
 435         s->client_cmds[SENDER_allow] = NULL;
 436         s->client_cmds[SENDER_add] = udp_com_add;
 437         s->client_cmds[SENDER_delete] = udp_com_delete;
 438         sender_status = SENDER_off;
 439         udp_init_target_list();
 440         if (!OPT_GIVEN(UDP_NO_AUTOSTART))
 441                 sender_status = SENDER_on;
 442         PARA_DEBUG_LOG("udp sender init complete\n");
 443 }