src/libsystemd-network/sd-ipv4ll.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright (C) 2014 Axis Communications AB. All rights reserved.
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stdlib.h>
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <stdio.h>
  24 #include <arpa/inet.h>
  25
  26 #include "util.h"
  27 #include "siphash24.h"
  28 #include "list.h"
  29 #include "refcnt.h"
  30
  31 #include "ipv4ll-internal.h"
  32 #include "sd-ipv4ll.h"
  33
  34 /* Constants from the RFC */
  35 #define PROBE_WAIT 1
  36 #define PROBE_NUM 3
  37 #define PROBE_MIN 1
  38 #define PROBE_MAX 2
  39 #define ANNOUNCE_WAIT 2
  40 #define ANNOUNCE_NUM 2
  41 #define ANNOUNCE_INTERVAL 2
  42 #define MAX_CONFLICTS 10
  43 #define RATE_LIMIT_INTERVAL 60
  44 #define DEFEND_INTERVAL 10
  45
  46 #define IPV4LL_NETWORK 0xA9FE0000L
  47 #define IPV4LL_NETMASK 0xFFFF0000L
  48
  49 typedef enum IPv4LLTrigger{
  50         IPV4LL_TRIGGER_NULL,
  51         IPV4LL_TRIGGER_PACKET,
  52         IPV4LL_TRIGGER_TIMEOUT,
  53         _IPV4LL_TRIGGER_MAX,
  54         _IPV4LL_TRIGGER_INVALID = -1
  55 } IPv4LLTrigger;
  56
  57 typedef enum IPv4LLState {
  58         IPV4LL_STATE_INIT,
  59         IPV4LL_STATE_WAITING_PROBE,
  60         IPV4LL_STATE_PROBING,
  61         IPV4LL_STATE_WAITING_ANNOUNCE,
  62         IPV4LL_STATE_ANNOUNCING,
  63         IPV4LL_STATE_RUNNING,
  64         IPV4LL_STATE_STOPPED,
  65         _IPV4LL_STATE_MAX,
  66         _IPV4LL_STATE_INVALID = -1
  67 } IPv4LLState;
  68
  69 struct sd_ipv4ll {
  70         RefCount n_ref;
  71
  72         IPv4LLState state;
  73         int index;
  74         int fd;
  75         union sockaddr_union link;
  76         int iteration;
  77         int conflict;
  78         sd_event_source *receive_message;
  79         sd_event_source *timer;
  80         usec_t next_wakeup;
  81         usec_t defend_window;
  82         int next_wakeup_valid;
  83         be32_t address;
  84         struct random_data *random_data;
  85         char *random_data_state;
  86         /* External */
  87         be32_t claimed_address;
  88         struct ether_addr mac_addr;
  89         sd_event *event;
  90         int event_priority;
  91         sd_ipv4ll_cb_t cb;
  92         void* userdata;
  93 };
  94
  95 static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data);
  96
  97 static void ipv4ll_set_state(sd_ipv4ll *ll, IPv4LLState st, int reset_counter) {
  98
  99         assert(ll);
 100         assert(st < _IPV4LL_STATE_MAX);
 101
 102         if (st == ll->state && !reset_counter) {
 103                 ll->iteration++;
 104         } else {
 105                 ll->state = st;
 106                 ll->iteration = 0;
 107         }
 108 }
 109
 110 static sd_ipv4ll *ipv4ll_client_notify(sd_ipv4ll *ll, int event) {
 111         assert(ll);
 112
 113         if (ll->cb) {
 114                 ll = sd_ipv4ll_ref(ll);
 115                 ll->cb(ll, event, ll->userdata);
 116                 ll = sd_ipv4ll_unref(ll);
 117         }
 118
 119         return ll;
 120 }
 121
 122 static sd_ipv4ll *ipv4ll_stop(sd_ipv4ll *ll, int event) {
 123         assert(ll);
 124
 125         ll->receive_message = sd_event_source_unref(ll->receive_message);
 126         ll->fd = safe_close(ll->fd);
 127
 128         ll->timer = sd_event_source_unref(ll->timer);
 129
 130         log_ipv4ll(ll, "STOPPED");
 131
 132         ll = ipv4ll_client_notify(ll, event);
 133
 134         if (ll) {
 135                 ll->claimed_address = 0;
 136                 ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
 137         }
 138
 139         return ll;
 140 }
 141
 142 static int ipv4ll_pick_address(sd_ipv4ll *ll, be32_t *address) {
 143         be32_t addr;
 144         int r;
 145         int32_t random;
 146
 147         assert(ll);
 148         assert(address);
 149         assert(ll->random_data);
 150
 151         do {
 152                 r = random_r(ll->random_data, &random);
 153                 if (r < 0)
 154                         return r;
 155                 addr = htonl((random & 0x0000FFFF) | IPV4LL_NETWORK);
 156         } while (addr == ll->address ||
 157                 (ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK ||
 158                 (ntohl(addr) & 0x0000FF00) == 0x0000 ||
 159                 (ntohl(addr) & 0x0000FF00) == 0xFF00);
 160
 161         *address = addr;
 162         return 0;
 163 }
 164
 165 static int ipv4ll_timer(sd_event_source *s, uint64_t usec, void *userdata) {
 166         sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
 167
 168         assert(ll);
 169
 170         ll->next_wakeup_valid = 0;
 171         ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_TIMEOUT, NULL);
 172
 173         return 0;
 174 }
 175
 176 static void ipv4ll_set_next_wakeup(sd_ipv4ll *ll, int sec, int random_sec) {
 177         usec_t next_timeout = 0;
 178         usec_t time_now = 0;
 179
 180         assert(sec >= 0);
 181         assert(random_sec >= 0);
 182         assert(ll);
 183
 184         next_timeout = sec * USEC_PER_SEC;
 185
 186         if (random_sec)
 187                 next_timeout += random_u32() % (random_sec * USEC_PER_SEC);
 188
 189         if (sd_event_now(ll->event, clock_boottime_or_monotonic(), &time_now) < 0)
 190                 time_now = now(clock_boottime_or_monotonic());
 191
 192         ll->next_wakeup = time_now + next_timeout;
 193         ll->next_wakeup_valid = 1;
 194 }
 195
 196 static bool ipv4ll_arp_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
 197         assert(ll);
 198         assert(arp);
 199
 200         if (memcmp(arp->arp_spa, &ll->address, sizeof(ll->address)) == 0 &&
 201             memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN) != 0)
 202                 return true;
 203
 204         return false;
 205 }
 206
 207 static bool ipv4ll_arp_probe_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
 208         assert(ll);
 209         assert(arp);
 210
 211         if (ipv4ll_arp_conflict(ll, arp))
 212                 return true;
 213
 214         if (memcmp(arp->arp_tpa, &ll->address, sizeof(ll->address)) == 0 &&
 215             memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN))
 216                 return true;
 217
 218         return false;
 219 }
 220
 221 static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data) {
 222         struct ether_arp out_packet;
 223         int out_packet_ready = 0;
 224         int r = 0;
 225
 226         assert(ll);
 227         assert(trigger < _IPV4LL_TRIGGER_MAX);
 228
 229         if (ll->state == IPV4LL_STATE_INIT) {
 230
 231                 log_ipv4ll(ll, "PROBE");
 232                 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
 233                 ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
 234
 235         } else if ((ll->state == IPV4LL_STATE_WAITING_PROBE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
 236                 (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < PROBE_NUM-2)) {
 237
 238                 /* Send a probe */
 239                 arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
 240                 out_packet_ready = 1;
 241                 ipv4ll_set_state(ll, IPV4LL_STATE_PROBING, 0);
 242
 243                 ipv4ll_set_next_wakeup(ll, PROBE_MIN, (PROBE_MAX-PROBE_MIN));
 244
 245         } else if (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration >= PROBE_NUM-2) {
 246
 247                 /* Send the last probe */
 248                 arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
 249                 out_packet_ready = 1;
 250                 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_ANNOUNCE, 1);
 251
 252                 ipv4ll_set_next_wakeup(ll, ANNOUNCE_WAIT, 0);
 253
 254         } else if ((ll->state == IPV4LL_STATE_WAITING_ANNOUNCE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
 255                 (ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < ANNOUNCE_NUM-1)) {
 256
 257                 /* Send announcement packet */
 258                 arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
 259                 out_packet_ready = 1;
 260                 ipv4ll_set_state(ll, IPV4LL_STATE_ANNOUNCING, 0);
 261
 262                 ipv4ll_set_next_wakeup(ll, ANNOUNCE_INTERVAL, 0);
 263
 264                 if (ll->iteration == 0) {
 265                         log_ipv4ll(ll, "ANNOUNCE");
 266                         ll->claimed_address = ll->address;
 267                         ll = ipv4ll_client_notify(ll, IPV4LL_EVENT_BIND);
 268                         if (!ll || ll->state == IPV4LL_STATE_STOPPED)
 269                                 goto out;
 270
 271                         ll->conflict = 0;
 272                 }
 273
 274         } else if ((ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT &&
 275                     ll->iteration >= ANNOUNCE_NUM-1)) {
 276
 277                 ipv4ll_set_state(ll, IPV4LL_STATE_RUNNING, 0);
 278                 ll->next_wakeup_valid = 0;
 279
 280         } else if (trigger == IPV4LL_TRIGGER_PACKET) {
 281
 282                 int conflicted = 0;
 283                 usec_t time_now;
 284                 struct ether_arp* in_packet = (struct ether_arp*)trigger_data;
 285
 286                 assert(in_packet);
 287
 288                 if (IN_SET(ll->state, IPV4LL_STATE_ANNOUNCING, IPV4LL_STATE_RUNNING)) {
 289
 290                         if (ipv4ll_arp_conflict(ll, in_packet)) {
 291
 292                                 r = sd_event_now(ll->event, clock_boottime_or_monotonic(), &time_now);
 293                                 if (r < 0)
 294                                         goto out;
 295
 296                                 /* Defend address */
 297                                 if (time_now > ll->defend_window) {
 298                                         ll->defend_window = time_now + DEFEND_INTERVAL * USEC_PER_SEC;
 299                                         arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
 300                                         out_packet_ready = 1;
 301                                 } else
 302                                         conflicted = 1;
 303                         }
 304
 305                 } else if (IN_SET(ll->state, IPV4LL_STATE_WAITING_PROBE,
 306                                              IPV4LL_STATE_PROBING,
 307                                              IPV4LL_STATE_WAITING_ANNOUNCE)) {
 308
 309                         conflicted = ipv4ll_arp_probe_conflict(ll, in_packet);
 310                 }
 311
 312                 if (conflicted) {
 313                         log_ipv4ll(ll, "CONFLICT");
 314                         ll = ipv4ll_client_notify(ll, IPV4LL_EVENT_CONFLICT);
 315                         if (!ll || ll->state == IPV4LL_STATE_STOPPED)
 316                                 goto out;
 317
 318                         ll->claimed_address = 0;
 319
 320                         /* Pick a new address */
 321                         r = ipv4ll_pick_address(ll, &ll->address);
 322                         if (r < 0)
 323                                 goto out;
 324                         ll->conflict++;
 325                         ll->defend_window = 0;
 326                         ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
 327
 328                         if (ll->conflict >= MAX_CONFLICTS) {
 329                                 log_ipv4ll(ll, "MAX_CONFLICTS");
 330                                 ipv4ll_set_next_wakeup(ll, RATE_LIMIT_INTERVAL, PROBE_WAIT);
 331                         } else
 332                                 ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
 333
 334                 }
 335         }
 336
 337         if (out_packet_ready) {
 338                 r = arp_network_send_raw_socket(ll->fd, &ll->link, &out_packet);
 339                 if (r < 0) {
 340                         log_ipv4ll(ll, "failed to send arp packet out");
 341                         goto out;
 342                 }
 343         }
 344
 345         if (ll->next_wakeup_valid) {
 346                 ll->timer = sd_event_source_unref(ll->timer);
 347                 r = sd_event_add_time(ll->event, &ll->timer, clock_boottime_or_monotonic(),
 348                                       ll->next_wakeup, 0, ipv4ll_timer, ll);
 349                 if (r < 0)
 350                         goto out;
 351
 352                 r = sd_event_source_set_priority(ll->timer, ll->event_priority);
 353                 if (r < 0)
 354                         goto out;
 355
 356                 r = sd_event_source_set_description(ll->timer, "ipv4ll-timer");
 357                 if (r < 0)
 358                         goto out;
 359         }
 360
 361 out:
 362         if (r < 0 && ll)
 363                 ipv4ll_stop(ll, r);
 364 }
 365
 366 static int ipv4ll_receive_message(sd_event_source *s, int fd,
 367                                   uint32_t revents, void *userdata) {
 368         int r;
 369         struct ether_arp arp;
 370         sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
 371
 372         assert(ll);
 373
 374         r = read(fd, &arp, sizeof(struct ether_arp));
 375         if (r < (int) sizeof(struct ether_arp))
 376                 return 0;
 377
 378         r = arp_packet_verify_headers(&arp);
 379         if (r < 0)
 380                 return 0;
 381
 382         ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_PACKET, &arp);
 383
 384         return 0;
 385 }
 386
 387 int sd_ipv4ll_set_index(sd_ipv4ll *ll, int interface_index) {
 388         assert_return(ll, -EINVAL);
 389         assert_return(interface_index > 0, -EINVAL);
 390         assert_return(IN_SET(ll->state, IPV4LL_STATE_INIT,
 391                              IPV4LL_STATE_STOPPED), -EBUSY);
 392
 393         ll->index = interface_index;
 394
 395         return 0;
 396 }
 397
 398 int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
 399         bool need_restart = false;
 400
 401         assert_return(ll, -EINVAL);
 402         assert_return(addr, -EINVAL);
 403
 404         if (memcmp(&ll->mac_addr, addr, ETH_ALEN) == 0)
 405                 return 0;
 406
 407         if (!IN_SET(ll->state, IPV4LL_STATE_INIT, IPV4LL_STATE_STOPPED)) {
 408                 log_ipv4ll(ll, "Changing MAC address on running IPv4LL "
 409                            "client, restarting");
 410                 ll = ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
 411                 need_restart = true;
 412         }
 413
 414         if (!ll)
 415                 return 0;
 416
 417         memcpy(&ll->mac_addr, addr, ETH_ALEN);
 418
 419         if (need_restart)
 420                 sd_ipv4ll_start(ll);
 421
 422         return 0;
 423 }
 424
 425 int sd_ipv4ll_detach_event(sd_ipv4ll *ll) {
 426         assert_return(ll, -EINVAL);
 427
 428         ll->event = sd_event_unref(ll->event);
 429
 430         return 0;
 431 }
 432
 433 int sd_ipv4ll_attach_event(sd_ipv4ll *ll, sd_event *event, int priority) {
 434         int r;
 435
 436         assert_return(ll, -EINVAL);
 437         assert_return(!ll->event, -EBUSY);
 438
 439         if (event)
 440                 ll->event = sd_event_ref(event);
 441         else {
 442                 r = sd_event_default(&ll->event);
 443                 if (r < 0) {
 444                         ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
 445                         return r;
 446                 }
 447         }
 448
 449         ll->event_priority = priority;
 450
 451         return 0;
 452 }
 453
 454 int sd_ipv4ll_set_callback(sd_ipv4ll *ll, sd_ipv4ll_cb_t cb, void *userdata) {
 455         assert_return(ll, -EINVAL);
 456
 457         ll->cb = cb;
 458         ll->userdata = userdata;
 459
 460         return 0;
 461 }
 462
 463 int sd_ipv4ll_get_address(sd_ipv4ll *ll, struct in_addr *address){
 464         assert_return(ll, -EINVAL);
 465         assert_return(address, -EINVAL);
 466
 467         if (ll->claimed_address == 0) {
 468                 return -ENOENT;
 469         }
 470
 471         address->s_addr = ll->claimed_address;
 472         return 0;
 473 }
 474
 475 int sd_ipv4ll_set_address_seed (sd_ipv4ll *ll, uint8_t seed[8]) {
 476         unsigned int entropy;
 477         int r;
 478
 479         assert_return(ll, -EINVAL);
 480         assert_return(seed, -EINVAL);
 481
 482         entropy = *seed;
 483
 484         free(ll->random_data);
 485         free(ll->random_data_state);
 486
 487         ll->random_data = new0(struct random_data, 1);
 488         ll->random_data_state = new0(char, 128);
 489
 490         if (!ll->random_data || !ll->random_data_state) {
 491                 r = -ENOMEM;
 492                 goto error;
 493         }
 494
 495         r = initstate_r((unsigned int)entropy, ll->random_data_state, 128, ll->random_data);
 496         if (r < 0)
 497                 goto error;
 498
 499 error:
 500         if (r < 0){
 501                 free(ll->random_data);
 502                 free(ll->random_data_state);
 503                 ll->random_data = NULL;
 504                 ll->random_data_state = NULL;
 505         }
 506         return r;
 507 }
 508
 509 bool sd_ipv4ll_is_running(sd_ipv4ll *ll) {
 510         assert_return(ll, -EINVAL);
 511
 512         return !IN_SET(ll->state, IPV4LL_STATE_INIT, IPV4LL_STATE_STOPPED);
 513 }
 514
 515 #define HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2)
 516
 517 int sd_ipv4ll_start (sd_ipv4ll *ll) {
 518         int r;
 519
 520         assert_return(ll, -EINVAL);
 521         assert_return(ll->event, -EINVAL);
 522         assert_return(ll->index > 0, -EINVAL);
 523         assert_return(IN_SET(ll->state, IPV4LL_STATE_INIT,
 524                              IPV4LL_STATE_STOPPED), -EBUSY);
 525
 526         ll->state = IPV4LL_STATE_INIT;
 527
 528         r = arp_network_bind_raw_socket(ll->index, &ll->link);
 529
 530         if (r < 0)
 531                 goto out;
 532
 533         ll->fd = r;
 534         ll->conflict = 0;
 535         ll->defend_window = 0;
 536         ll->claimed_address = 0;
 537
 538         if (!ll->random_data) {
 539                 uint8_t seed[8];
 540
 541                 /* Fallback to mac */
 542                 siphash24(seed, &ll->mac_addr.ether_addr_octet,
 543                           ETH_ALEN, HASH_KEY.bytes);
 544
 545                 r = sd_ipv4ll_set_address_seed(ll, seed);
 546                 if (r < 0)
 547                         goto out;
 548         }
 549
 550         if (ll->address == 0) {
 551                 r = ipv4ll_pick_address(ll, &ll->address);
 552                 if (r < 0)
 553                         goto out;
 554         }
 555
 556         ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
 557
 558         r = sd_event_add_io(ll->event, &ll->receive_message, ll->fd,
 559                             EPOLLIN, ipv4ll_receive_message, ll);
 560         if (r < 0)
 561                 goto out;
 562
 563         r = sd_event_source_set_priority(ll->receive_message, ll->event_priority);
 564         if (r < 0)
 565                 goto out;
 566
 567         r = sd_event_source_set_description(ll->receive_message, "ipv4ll-receive-message");
 568         if (r < 0)
 569                 goto out;
 570
 571         r = sd_event_add_time(ll->event,
 572                               &ll->timer,
 573                               clock_boottime_or_monotonic(),
 574                               now(clock_boottime_or_monotonic()), 0,
 575                               ipv4ll_timer, ll);
 576
 577         if (r < 0)
 578                 goto out;
 579
 580         r = sd_event_source_set_priority(ll->timer, ll->event_priority);
 581         if (r < 0)
 582                 goto out;
 583
 584         r = sd_event_source_set_description(ll->timer, "ipv4ll-timer");
 585 out:
 586         if (r < 0)
 587                 ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
 588
 589         return 0;
 590 }
 591
 592 int sd_ipv4ll_stop(sd_ipv4ll *ll) {
 593         ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
 594         if (ll)
 595                 ipv4ll_set_state(ll, IPV4LL_STATE_STOPPED, 1);
 596
 597         return 0;
 598 }
 599
 600 sd_ipv4ll *sd_ipv4ll_ref(sd_ipv4ll *ll) {
 601         if (ll)
 602                 assert_se(REFCNT_INC(ll->n_ref) >= 2);
 603
 604         return ll;
 605 }
 606
 607 sd_ipv4ll *sd_ipv4ll_unref(sd_ipv4ll *ll) {
 608         if (ll && REFCNT_DEC(ll->n_ref) <= 0) {
 609                 ll->receive_message =
 610                         sd_event_source_unref(ll->receive_message);
 611                 ll->fd = safe_close(ll->fd);
 612
 613                 ll->timer = sd_event_source_unref(ll->timer);
 614
 615                 sd_ipv4ll_detach_event(ll);
 616
 617                 free(ll->random_data);
 618                 free(ll->random_data_state);
 619                 free(ll);
 620
 621                 return NULL;
 622         }
 623
 624         return ll;
 625 }
 626
 627 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_ipv4ll*, sd_ipv4ll_unref);
 628 #define _cleanup_ipv4ll_free_ _cleanup_(sd_ipv4ll_unrefp)
 629
 630 int sd_ipv4ll_new(sd_ipv4ll **ret) {
 631         _cleanup_ipv4ll_free_ sd_ipv4ll *ll = NULL;
 632
 633         assert_return(ret, -EINVAL);
 634
 635         ll = new0(sd_ipv4ll, 1);
 636         if (!ll)
 637                 return -ENOMEM;
 638
 639         ll->n_ref = REFCNT_INIT;
 640         ll->state = IPV4LL_STATE_INIT;
 641         ll->index = -1;
 642         ll->fd = -1;
 643
 644         *ret = ll;
 645         ll = NULL;
 646
 647         return 0;
 648 }