bfdd/ptm_adapter.c

   1 /*
   2  * BFD PTM adapter code
   3  * Copyright (C) 2018 Network Device Education Foundation, Inc. ("NetDEF")
   4  *
   5  * FRR is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2, or (at your option) any
   8  * later version.
   9  *
  10  * FRR is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with FRR; see the file COPYING.  If not, write to the Free
  17  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  18  * 02111-1307, USA.
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include "lib/libfrr.h"
  24 #include "lib/queue.h"
  25 #include "lib/stream.h"
  26 #include "lib/zclient.h"
  27
  28 #include "lib/bfd.h"
  29
  30 #include "bfd.h"
  31
  32 /*
  33  * Data structures
  34  */
  35 struct ptm_client_notification {
  36         struct bfd_session *pcn_bs;
  37         struct ptm_client *pcn_pc;
  38
  39         TAILQ_ENTRY(ptm_client_notification) pcn_entry;
  40 };
  41 TAILQ_HEAD(pcnqueue, ptm_client_notification);
  42
  43 struct ptm_client {
  44         uint32_t pc_pid;
  45         struct pcnqueue pc_pcnqueue;
  46
  47         TAILQ_ENTRY(ptm_client) pc_entry;
  48 };
  49 TAILQ_HEAD(pcqueue, ptm_client);
  50
  51 static struct pcqueue pcqueue;
  52 static struct zclient *zclient;
  53
  54
  55 /*
  56  * Prototypes
  57  */
  58 static int _ptm_msg_address(struct stream *msg, struct sockaddr_any *sa);
  59
  60 static void _ptm_msg_read_address(struct stream *msg, struct sockaddr_any *sa);
  61 static int _ptm_msg_read(struct stream *msg, int command,
  62                          struct bfd_peer_cfg *bpc, struct ptm_client **pc);
  63
  64 static struct ptm_client *pc_lookup(uint32_t pid);
  65 static struct ptm_client *pc_new(uint32_t pid);
  66 static void pc_free(struct ptm_client *pc);
  67 static void pc_free_all(void);
  68 static struct ptm_client_notification *pcn_new(struct ptm_client *pc,
  69                                                struct bfd_session *bs);
  70 static struct ptm_client_notification *pcn_lookup(struct ptm_client *pc,
  71                                                   struct bfd_session *bs);
  72 static void pcn_free(struct ptm_client_notification *pcn);
  73
  74
  75 static void bfdd_dest_register(struct stream *msg);
  76 static void bfdd_dest_deregister(struct stream *msg);
  77 static void bfdd_client_register(struct stream *msg);
  78 static void bfdd_client_deregister(struct stream *msg);
  79
  80 /*
  81  * Functions
  82  */
  83 #ifdef BFD_DEBUG
  84 static void debug_printbpc(const char *func, unsigned int line,
  85                            struct bfd_peer_cfg *bpc);
  86
  87 static void debug_printbpc(const char *func, unsigned int line,
  88                            struct bfd_peer_cfg *bpc)
  89 {
  90         char addr[3][128];
  91         char timers[3][128];
  92
  93         addr[0][0] = addr[1][0] = addr[2][0] = timers[0][0] = timers[1][0] =
  94                 timers[2][0] = 0;
  95
  96         snprintf(addr[0], sizeof(addr[0]), "peer:%s", satostr(&bpc->bpc_peer));
  97         if (bpc->bpc_local.sa_sin.sin_family)
  98                 snprintf(addr[1], sizeof(addr[1]), " local:%s",
  99                          satostr(&bpc->bpc_local));
 100
 101         if (bpc->bpc_has_localif)
 102                 snprintf(addr[2], sizeof(addr[2]), " ifname:%s",
 103                          bpc->bpc_localif);
 104
 105         if (bpc->bpc_has_vrfname)
 106                 snprintf(addr[2], sizeof(addr[2]), " vrf:%s", bpc->bpc_vrfname);
 107
 108         if (bpc->bpc_has_recvinterval)
 109                 snprintf(timers[0], sizeof(timers[0]), " rx:%lu",
 110                          bpc->bpc_recvinterval);
 111
 112         if (bpc->bpc_has_txinterval)
 113                 snprintf(timers[1], sizeof(timers[1]), " tx:%lu",
 114                          bpc->bpc_recvinterval);
 115
 116         if (bpc->bpc_has_detectmultiplier)
 117                 snprintf(timers[2], sizeof(timers[2]), " detect-multiplier:%d",
 118                          bpc->bpc_detectmultiplier);
 119
 120         log_debug("%s:%d: %s %s%s%s%s%s%s", func, line,
 121                   bpc->bpc_mhop ? "multi-hop" : "single-hop", addr[0], addr[1],
 122                   addr[2], timers[0], timers[1], timers[2]);
 123 }
 124
 125 #define DEBUG_PRINTBPC(bpc) debug_printbpc(__FILE__, __LINE__, (bpc))
 126 #else
 127 #define DEBUG_PRINTBPC(bpc)
 128 #endif /* BFD_DEBUG */
 129
 130 static int _ptm_msg_address(struct stream *msg, struct sockaddr_any *sa)
 131 {
 132         switch (sa->sa_sin.sin_family) {
 133         case AF_INET:
 134                 stream_putc(msg, sa->sa_sin.sin_family);
 135                 stream_put_in_addr(msg, &sa->sa_sin.sin_addr);
 136                 stream_putc(msg, 32);
 137                 break;
 138
 139         case AF_INET6:
 140                 stream_putc(msg, sa->sa_sin6.sin6_family);
 141                 stream_put(msg, &sa->sa_sin6.sin6_addr,
 142                            sizeof(sa->sa_sin6.sin6_addr));
 143                 stream_putc(msg, 128);
 144                 break;
 145
 146         default:
 147                 return -1;
 148         }
 149
 150         return 0;
 151 }
 152
 153 int ptm_bfd_notify(struct bfd_session *bs)
 154 {
 155         struct stream *msg;
 156         struct sockaddr_any sac;
 157
 158         bs->stats.znotification++;
 159
 160         /*
 161          * Message format:
 162          * - header: command, vrf
 163          * - l: interface index
 164          * - c: family
 165          *   - AF_INET:
 166          *     - 4 bytes: ipv4
 167          *   - AF_INET6:
 168          *     - 16 bytes: ipv6
 169          *   - c: prefix length
 170          * - l: bfd status
 171          * - c: family
 172          *   - AF_INET:
 173          *     - 4 bytes: ipv4
 174          *   - AF_INET6:
 175          *     - 16 bytes: ipv6
 176          *   - c: prefix length
 177          *
 178          * Commands: ZEBRA_BFD_DEST_REPLAY
 179          *
 180          * q(64), l(32), w(16), c(8)
 181          */
 182         msg = zclient->obuf;
 183         stream_reset(msg);
 184
 185         /* TODO: VRF handling */
 186         zclient_create_header(msg, ZEBRA_BFD_DEST_REPLAY, VRF_DEFAULT);
 187
 188         /* This header will be handled by `zebra_ptm.c`. */
 189         stream_putl(msg, ZEBRA_INTERFACE_BFD_DEST_UPDATE);
 190
 191         /* NOTE: Interface is a shortcut to avoid comparing source address. */
 192         stream_putl(msg, bs->ifindex);
 193
 194         /* BFD destination prefix information. */
 195         if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
 196                 _ptm_msg_address(msg, &bs->mhop.peer);
 197         else
 198                 _ptm_msg_address(msg, &bs->shop.peer);
 199
 200         /* BFD status */
 201         switch (bs->ses_state) {
 202         case PTM_BFD_UP:
 203                 stream_putl(msg, BFD_STATUS_UP);
 204                 break;
 205
 206         case PTM_BFD_ADM_DOWN:
 207         case PTM_BFD_DOWN:
 208         case PTM_BFD_INIT:
 209                 stream_putl(msg, BFD_STATUS_DOWN);
 210                 break;
 211
 212         default:
 213                 stream_putl(msg, BFD_STATUS_UNKNOWN);
 214                 break;
 215         }
 216
 217         /* BFD source prefix information. */
 218         if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH)) {
 219                 _ptm_msg_address(msg, &bs->mhop.local);
 220         } else {
 221                 if (bs->local_address.sa_sin.sin_family)
 222                         _ptm_msg_address(msg, &bs->local_address);
 223                 else if (bs->local_address.sa_sin.sin_family)
 224                         _ptm_msg_address(msg, &bs->local_ip);
 225                 else {
 226                         sac = bs->shop.peer;
 227                         switch (sac.sa_sin.sin_family) {
 228                         case AF_INET:
 229                                 memset(&sac.sa_sin.sin_addr, 0,
 230                                        sizeof(sac.sa_sin.sin_family));
 231                                 break;
 232                         case AF_INET6:
 233                                 memset(&sac.sa_sin6.sin6_addr, 0,
 234                                        sizeof(sac.sa_sin6.sin6_family));
 235                                 break;
 236
 237                         default:
 238                                 assert(false);
 239                                 break;
 240                         }
 241
 242                         /* No local address found yet, so send zeroes. */
 243                         _ptm_msg_address(msg, &sac);
 244                 }
 245         }
 246
 247         /* Write packet size. */
 248         stream_putw_at(msg, 0, stream_get_endp(msg));
 249
 250         return zclient_send_message(zclient);
 251 }
 252
 253 static void _ptm_msg_read_address(struct stream *msg, struct sockaddr_any *sa)
 254 {
 255         uint16_t family;
 256
 257         STREAM_GETW(msg, family);
 258
 259         switch (family) {
 260         case AF_INET:
 261                 sa->sa_sin.sin_family = family;
 262                 STREAM_GET(&sa->sa_sin.sin_addr, msg,
 263                            sizeof(sa->sa_sin.sin_addr));
 264 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
 265                 sa->sa_sin.sin_len = sizeof(sa->sa_sin);
 266 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
 267                 return;
 268
 269         case AF_INET6:
 270                 sa->sa_sin6.sin6_family = family;
 271                 STREAM_GET(&sa->sa_sin6.sin6_addr, msg,
 272                            sizeof(sa->sa_sin6.sin6_addr));
 273 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
 274                 sa->sa_sin6.sin6_len = sizeof(sa->sa_sin6);
 275 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
 276                 return;
 277
 278         default:
 279                 log_warning("ptm-read-address: invalid family: %d", family);
 280                 break;
 281         }
 282
 283 stream_failure:
 284         memset(sa, 0, sizeof(*sa));
 285 }
 286
 287 static int _ptm_msg_read(struct stream *msg, int command,
 288                          struct bfd_peer_cfg *bpc, struct ptm_client **pc)
 289 {
 290         uint32_t pid;
 291         uint8_t ttl __attribute__((unused));
 292         uint8_t ifnamelen;
 293
 294         /*
 295          * Register/Deregister/Update Message format:
 296          * - header: Command, VRF
 297          * - l: pid
 298          * - w: family
 299          *   - AF_INET:
 300          *     - l: destination ipv4
 301          *   - AF_INET6:
 302          *     - 16 bytes: destination IPv6
 303          * - command != ZEBRA_BFD_DEST_DEREGISTER
 304          *   - l: min_rx
 305          *   - l: min_tx
 306          *   - c: detect multiplier
 307          * - c: is_multihop?
 308          *   - multihop:
 309          *     - w: family
 310          *       - AF_INET:
 311          *         - l: destination ipv4
 312          *       - AF_INET6:
 313          *         - 16 bytes: destination IPv6
 314          *     - c: ttl
 315          *   - no multihop
 316          *     - AF_INET6:
 317          *       - w: family
 318          *       - 16 bytes: ipv6 address
 319          *     - c: ifname length
 320          *     - X bytes: interface name
 321          *
 322          * q(64), l(32), w(16), c(8)
 323          */
 324
 325         /* Initialize parameters return values. */
 326         memset(bpc, 0, sizeof(*bpc));
 327         *pc = NULL;
 328
 329         /* Find or allocate process context data. */
 330         STREAM_GETL(msg, pid);
 331
 332         *pc = pc_new(pid);
 333         if (*pc == NULL) {
 334                 log_debug("ptm-read: failed to allocate memory");
 335                 return -1;
 336         }
 337
 338         /* Register/update peer information. */
 339         _ptm_msg_read_address(msg, &bpc->bpc_peer);
 340
 341         /* Determine IP type from peer destination. */
 342         bpc->bpc_ipv4 = (bpc->bpc_peer.sa_sin.sin_family == AF_INET);
 343
 344         /* Get peer configuration. */
 345         if (command != ZEBRA_BFD_DEST_DEREGISTER) {
 346                 STREAM_GETL(msg, bpc->bpc_recvinterval);
 347                 bpc->bpc_has_recvinterval =
 348                         (bpc->bpc_recvinterval != BPC_DEF_RECEIVEINTERVAL);
 349
 350                 STREAM_GETL(msg, bpc->bpc_txinterval);
 351                 bpc->bpc_has_txinterval =
 352                         (bpc->bpc_txinterval != BPC_DEF_TRANSMITINTERVAL);
 353
 354                 STREAM_GETC(msg, bpc->bpc_detectmultiplier);
 355                 bpc->bpc_has_detectmultiplier =
 356                         (bpc->bpc_detectmultiplier != BPC_DEF_DETECTMULTIPLIER);
 357         }
 358
 359         /* Read (single|multi)hop and its options. */
 360         STREAM_GETC(msg, bpc->bpc_mhop);
 361         if (bpc->bpc_mhop) {
 362                 /* Read multihop source address and TTL. */
 363                 _ptm_msg_read_address(msg, &bpc->bpc_local);
 364                 STREAM_GETC(msg, ttl);
 365         } else {
 366                 /* If target is IPv6, then we must obtain local address. */
 367                 if (bpc->bpc_ipv4 == false)
 368                         _ptm_msg_read_address(msg, &bpc->bpc_local);
 369
 370                 /*
 371                  * Read interface name and make sure it fits our data
 372                  * structure, otherwise fail.
 373                  */
 374                 STREAM_GETC(msg, ifnamelen);
 375                 if (ifnamelen >= sizeof(bpc->bpc_localif)) {
 376                         log_error("ptm-read: interface name is too big");
 377                         return -1;
 378                 }
 379
 380                 bpc->bpc_has_localif = ifnamelen > 0;
 381                 if (bpc->bpc_has_localif) {
 382                         STREAM_GET(bpc->bpc_localif, msg, ifnamelen);
 383                         bpc->bpc_localif[ifnamelen] = 0;
 384                 }
 385         }
 386
 387         /* Sanity check: peer and local address must match IP types. */
 388         if (bpc->bpc_local.sa_sin.sin_family != 0
 389             && (bpc->bpc_local.sa_sin.sin_family
 390                 != bpc->bpc_peer.sa_sin.sin_family)) {
 391                 log_warning("ptm-read: peer family doesn't match local type");
 392                 return -1;
 393         }
 394
 395         return 0;
 396
 397 stream_failure:
 398         return -1;
 399 }
 400
 401 static void bfdd_dest_register(struct stream *msg)
 402 {
 403         struct ptm_client *pc;
 404         struct ptm_client_notification *pcn;
 405         struct bfd_session *bs;
 406         struct bfd_peer_cfg bpc;
 407
 408         /* Read the client context and peer data. */
 409         if (_ptm_msg_read(msg, ZEBRA_BFD_DEST_REGISTER, &bpc, &pc) == -1)
 410                 return;
 411
 412         DEBUG_PRINTBPC(&bpc);
 413
 414         /* Find or start new BFD session. */
 415         bs = bs_peer_find(&bpc);
 416         if (bs == NULL) {
 417                 bs = ptm_bfd_sess_new(&bpc);
 418                 if (bs == NULL) {
 419                         log_debug("ptm-add-dest: failed to create BFD session");
 420                         return;
 421                 }
 422         } else {
 423                 /* Don't try to change echo/shutdown state. */
 424                 bpc.bpc_echo = BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
 425                 bpc.bpc_shutdown =
 426                         BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);
 427         }
 428
 429         /* Create client peer notification register. */
 430         pcn = pcn_new(pc, bs);
 431         if (pcn == NULL) {
 432                 log_error("ptm-add-dest: failed to registrate notifications");
 433                 return;
 434         }
 435
 436         ptm_bfd_notify(bs);
 437 }
 438
 439 static void bfdd_dest_deregister(struct stream *msg)
 440 {
 441         struct ptm_client *pc;
 442         struct ptm_client_notification *pcn;
 443         struct bfd_session *bs;
 444         struct bfd_peer_cfg bpc;
 445
 446         /* Read the client context and peer data. */
 447         if (_ptm_msg_read(msg, ZEBRA_BFD_DEST_DEREGISTER, &bpc, &pc) == -1)
 448                 return;
 449
 450         DEBUG_PRINTBPC(&bpc);
 451
 452         /* Find or start new BFD session. */
 453         bs = bs_peer_find(&bpc);
 454         if (bs == NULL) {
 455                 log_debug("ptm-del-dest: failed to find BFD session");
 456                 return;
 457         }
 458
 459         /* Unregister client peer notification. */
 460         pcn = pcn_lookup(pc, bs);
 461         pcn_free(pcn);
 462 }
 463
 464 /*
 465  * header: command, VRF
 466  * l: pid
 467  */
 468 static void bfdd_client_register(struct stream *msg)
 469 {
 470         struct ptm_client *pc;
 471         uint32_t pid;
 472
 473         /* Find or allocate process context data. */
 474         STREAM_GETL(msg, pid);
 475
 476         pc = pc_new(pid);
 477         if (pc == NULL) {
 478                 log_error("ptm-add-client: failed to register client: %u", pid);
 479                 return;
 480         }
 481
 482         return;
 483
 484 stream_failure:
 485         log_error("ptm-add-client: failed to register client");
 486 }
 487
 488 /*
 489  * header: command, VRF
 490  * l: pid
 491  */
 492 static void bfdd_client_deregister(struct stream *msg)
 493 {
 494         struct ptm_client *pc;
 495         uint32_t pid;
 496
 497         /* Find or allocate process context data. */
 498         STREAM_GETL(msg, pid);
 499
 500         pc = pc_lookup(pid);
 501         if (pc == NULL) {
 502                 log_debug("ptm-del-client: failed to find client: %u", pid);
 503                 return;
 504         }
 505
 506         pc_free(pc);
 507
 508         return;
 509
 510 stream_failure:
 511         log_error("ptm-del-client: failed to deregister client");
 512 }
 513
 514 static int bfdd_replay(int cmd, struct zclient *zc, uint16_t len, vrf_id_t vid)
 515 {
 516         struct stream *msg = zc->ibuf;
 517         uint32_t rcmd;
 518
 519         STREAM_GETL(msg, rcmd);
 520
 521         switch (rcmd) {
 522         case ZEBRA_BFD_DEST_REGISTER:
 523         case ZEBRA_BFD_DEST_UPDATE:
 524                 bfdd_dest_register(msg);
 525                 break;
 526         case ZEBRA_BFD_DEST_DEREGISTER:
 527                 bfdd_dest_deregister(msg);
 528                 break;
 529         case ZEBRA_BFD_CLIENT_REGISTER:
 530                 bfdd_client_register(msg);
 531                 break;
 532         case ZEBRA_BFD_CLIENT_DEREGISTER:
 533                 bfdd_client_deregister(msg);
 534                 break;
 535
 536         default:
 537                 log_debug("ptm-replay: invalid message type %u", rcmd);
 538                 return -1;
 539         }
 540
 541         return 0;
 542
 543 stream_failure:
 544         log_error("ptm-replay: failed to find command");
 545         return -1;
 546 }
 547
 548 static void bfdd_zebra_connected(struct zclient *zc)
 549 {
 550         struct stream *msg = zc->obuf;
 551
 552         /* Clean-up and free ptm clients data memory. */
 553         pc_free_all();
 554
 555         /*
 556          * The replay is an empty message just to trigger client daemons
 557          * configuration replay.
 558          */
 559         stream_reset(msg);
 560         zclient_create_header(msg, ZEBRA_BFD_DEST_REPLAY, VRF_DEFAULT);
 561         stream_putl(msg, ZEBRA_BFD_DEST_REPLAY);
 562         stream_putw_at(msg, 0, stream_get_endp(msg));
 563
 564         zclient_send_message(zclient);
 565 }
 566
 567 void bfdd_zclient_init(struct zebra_privs_t *bfdd_priv)
 568 {
 569         zclient = zclient_new_notify(master, &zclient_options_default);
 570         assert(zclient != NULL);
 571         zclient_init(zclient, ZEBRA_ROUTE_BFD, 0, bfdd_priv);
 572
 573         /*
 574          * We'll receive all messages through replay, however it will
 575          * contain a special field with the real command inside so we
 576          * avoid having to create too many handlers.
 577          */
 578         zclient->bfd_dest_replay = bfdd_replay;
 579
 580         /* Send replay request on zebra connect. */
 581         zclient->zebra_connected = bfdd_zebra_connected;
 582 }
 583
 584 void bfdd_zclient_stop(void)
 585 {
 586         zclient_stop(zclient);
 587
 588         /* Clean-up and free ptm clients data memory. */
 589         pc_free_all();
 590 }
 591
 592
 593 /*
 594  * Client handling.
 595  */
 596 static struct ptm_client *pc_lookup(uint32_t pid)
 597 {
 598         struct ptm_client *pc;
 599
 600         TAILQ_FOREACH (pc, &pcqueue, pc_entry) {
 601                 if (pc->pc_pid != pid)
 602                         continue;
 603
 604                 break;
 605         }
 606
 607         return pc;
 608 }
 609
 610 static struct ptm_client *pc_new(uint32_t pid)
 611 {
 612         struct ptm_client *pc;
 613
 614         /* Look up first, if not found create the client. */
 615         pc = pc_lookup(pid);
 616         if (pc != NULL)
 617                 return pc;
 618
 619         /* Allocate the client data and save it. */
 620         pc = XCALLOC(MTYPE_BFDD_CONTROL, sizeof(*pc));
 621         if (pc == NULL)
 622                 return NULL;
 623
 624         pc->pc_pid = pid;
 625         TAILQ_INSERT_HEAD(&pcqueue, pc, pc_entry);
 626         return pc;
 627 }
 628
 629 static void pc_free(struct ptm_client *pc)
 630 {
 631         struct ptm_client_notification *pcn;
 632
 633         if (pc == NULL)
 634                 return;
 635
 636         TAILQ_REMOVE(&pcqueue, pc, pc_entry);
 637
 638         while (!TAILQ_EMPTY(&pc->pc_pcnqueue)) {
 639                 pcn = TAILQ_FIRST(&pc->pc_pcnqueue);
 640                 pcn_free(pcn);
 641         }
 642
 643         XFREE(MTYPE_BFDD_CONTROL, pc);
 644 }
 645
 646 static void pc_free_all(void)
 647 {
 648         struct ptm_client *pc;
 649
 650         while (!TAILQ_EMPTY(&pcqueue)) {
 651                 pc = TAILQ_FIRST(&pcqueue);
 652                 pc_free(pc);
 653         }
 654 }
 655
 656 static struct ptm_client_notification *pcn_new(struct ptm_client *pc,
 657                                                struct bfd_session *bs)
 658 {
 659         struct ptm_client_notification *pcn;
 660
 661         /* Try to find an existing pcn fist. */
 662         pcn = pcn_lookup(pc, bs);
 663         if (pcn != NULL)
 664                 return pcn;
 665
 666         /* Save the client notification data. */
 667         pcn = XCALLOC(MTYPE_BFDD_NOTIFICATION, sizeof(*pcn));
 668         if (pcn == NULL)
 669                 return NULL;
 670
 671         TAILQ_INSERT_HEAD(&pc->pc_pcnqueue, pcn, pcn_entry);
 672         pcn->pcn_pc = pc;
 673         pcn->pcn_bs = bs;
 674         bs->refcount++;
 675
 676         return pcn;
 677 }
 678
 679 static struct ptm_client_notification *pcn_lookup(struct ptm_client *pc,
 680                                                   struct bfd_session *bs)
 681 {
 682         struct ptm_client_notification *pcn;
 683
 684         TAILQ_FOREACH (pcn, &pc->pc_pcnqueue, pcn_entry) {
 685                 if (pcn->pcn_bs != bs)
 686                         continue;
 687
 688                 break;
 689         }
 690
 691         return pcn;
 692 }
 693
 694 static void pcn_free(struct ptm_client_notification *pcn)
 695 {
 696         struct ptm_client *pc;
 697         struct bfd_session *bs;
 698
 699         if (pcn == NULL)
 700                 return;
 701
 702         /* Handle session de-registration. */
 703         bs = pcn->pcn_bs;
 704         pcn->pcn_bs = NULL;
 705         bs->refcount--;
 706
 707         /* Handle ptm_client deregistration. */
 708         pc = pcn->pcn_pc;
 709         pcn->pcn_pc = NULL;
 710         TAILQ_REMOVE(&pc->pc_pcnqueue, pcn, pcn_entry);
 711
 712         XFREE(MTYPE_BFDD_NOTIFICATION, pcn);
 713 }