eigrpd/eigrp_hello.c

   1 /*
   2  * EIGRP Sending and Receiving EIGRP Hello Packets.
   3  * Copyright (C) 2013-2016
   4  * Authors:
   5  *   Donnie Savage
   6  *   Jan Janovic
   7  *   Matej Perina
   8  *   Peter Orsag
   9  *   Peter Paluch
  10  *   Frantisek Gazo
  11  *   Tomas Hvorkovy
  12  *   Martin Kontsek
  13  *   Lukas Koribsky
  14  *
  15  * This file is part of GNU Zebra.
  16  *
  17  * GNU Zebra is free software; you can redistribute it and/or modify it
  18  * under the terms of the GNU General Public License as published by the
  19  * Free Software Foundation; either version 2, or (at your option) any
  20  * later version.
  21  *
  22  * GNU Zebra is distributed in the hope that it will be useful, but
  23  * WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25  * General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License along
  28  * with this program; see the file COPYING; if not, write to the Free Software
  29  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  30  */
  31
  32 #include <zebra.h>
  33
  34 #include "thread.h"
  35 #include "memory.h"
  36 #include "linklist.h"
  37 #include "prefix.h"
  38 #include "if.h"
  39 #include "table.h"
  40 #include "sockunion.h"
  41 #include "stream.h"
  42 #include "log.h"
  43 #include "sockopt.h"
  44 #include "checksum.h"
  45 #include "vty.h"
  46 #include "md5.h"
  47
  48 #include "eigrpd/eigrp_structs.h"
  49 #include "eigrpd/eigrpd.h"
  50 #include "eigrpd/eigrp_interface.h"
  51 #include "eigrpd/eigrp_neighbor.h"
  52 #include "eigrpd/eigrp_packet.h"
  53 #include "eigrpd/eigrp_zebra.h"
  54 #include "eigrpd/eigrp_vty.h"
  55 #include "eigrpd/eigrp_dump.h"
  56 #include "eigrpd/eigrp_macros.h"
  57 #include "eigrpd/eigrp_errors.h"
  58
  59 /* Packet Type String. */
  60 static const struct message eigrp_general_tlv_type_str[] = {
  61         {EIGRP_TLV_PARAMETER, "PARAMETER"},
  62         {EIGRP_TLV_AUTH, "AUTH"},
  63         {EIGRP_TLV_SEQ, "SEQ"},
  64         {EIGRP_TLV_SW_VERSION, "SW_VERSION"},
  65         {EIGRP_TLV_NEXT_MCAST_SEQ, "NEXT_MCAST_SEQ"},
  66         {EIGRP_TLV_PEER_TERMINATION, "PEER_TERMINATION"},
  67         {EIGRP_TLV_PEER_MTRLIST, "PEER_MTRLIST"},
  68         {EIGRP_TLV_PEER_TIDLIST, "PEER_TIDLIST"},
  69         {0}};
  70
  71
  72 /*
  73  * @fn eigrp_hello_timer
  74  *
  75  * @param[in]   thread  current execution thread timer is associated with
  76  *
  77  * @return int  always returns 0
  78  *
  79  * @par
  80  * Called once per "hello" time interval, default 5 seconds
  81  * Sends hello packet via multicast for all interfaces eigrp
  82  * is configured for
  83  */
  84 int eigrp_hello_timer(struct thread *thread)
  85 {
  86         struct eigrp_interface *ei;
  87
  88         ei = THREAD_ARG(thread);
  89         ei->t_hello = NULL;
  90
  91         if (IS_DEBUG_EIGRP(0, TIMERS))
  92                 zlog_debug("Start Hello Timer (%s) Expire [%u]", IF_NAME(ei),
  93                            ei->params.v_hello);
  94
  95         /* Sending hello packet. */
  96         eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL);
  97
  98         /* Hello timer set. */
  99         ei->t_hello = NULL;
 100         thread_add_timer(master, eigrp_hello_timer, ei, ei->params.v_hello,
 101                          &ei->t_hello);
 102
 103         return 0;
 104 }
 105
 106 /**
 107  * @fn eigrp_hello_parameter_decode
 108  *
 109  * @param[in]           nbr     neighbor the ACK should be sent to
 110  * @param[in]           param   pointer packet TLV is stored to
 111  *
 112  * @return uint16_t     number of bytes added to packet stream
 113  *
 114  * @par
 115  * Encode Parameter TLV, used to convey metric weights and the hold time.
 116  *
 117  * @usage
 118  * Note the addition of K6 for the new extended metrics, and does not apply to
 119  * older TLV packet formats.
 120  */
 121 static struct eigrp_neighbor *
 122 eigrp_hello_parameter_decode(struct eigrp_neighbor *nbr,
 123                              struct eigrp_tlv_hdr_type *tlv)
 124 {
 125         struct eigrp *eigrp = nbr->ei->eigrp;
 126         struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv;
 127
 128         /* copy over the values passed in by the neighbor */
 129         nbr->K1 = param->K1;
 130         nbr->K2 = param->K2;
 131         nbr->K3 = param->K3;
 132         nbr->K4 = param->K4;
 133         nbr->K5 = param->K5;
 134         nbr->K6 = param->K6;
 135         nbr->v_holddown = ntohs(param->hold_time);
 136
 137         /*
 138          * Check K1-K5 have the correct values to be able to become neighbors
 139          * K6 does not have to match
 140          */
 141         if ((eigrp->k_values[0] == nbr->K1) && (eigrp->k_values[1] == nbr->K2)
 142             && (eigrp->k_values[2] == nbr->K3)
 143             && (eigrp->k_values[3] == nbr->K4)
 144             && (eigrp->k_values[4] == nbr->K5)) {
 145
 146                 if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN) {
 147                         zlog_info("Neighbor %s (%s) is pending: new adjacency",
 148                                   inet_ntoa(nbr->src),
 149                                   ifindex2ifname(nbr->ei->ifp->ifindex,
 150                                                  VRF_DEFAULT));
 151
 152                         /* Expedited hello sent */
 153                         eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL);
 154
 155                         //     if(ntohl(nbr->ei->address->u.prefix4.s_addr) >
 156                         //     ntohl(nbr->src.s_addr))
 157                         eigrp_update_send_init(nbr);
 158
 159                         eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 160                 }
 161         } else {
 162                 if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN) {
 163                         if ((param->K1 & param->K2 & param->K3 & param->K4
 164                              & param->K5)
 165                             == 255) {
 166                                 zlog_info(
 167                                         "Neighbor %s (%s) is down: Interface PEER-TERMINATION received",
 168                                         inet_ntoa(nbr->src),
 169                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 170                                                        VRF_DEFAULT));
 171                                 eigrp_nbr_delete(nbr);
 172                                 return NULL;
 173                         } else {
 174                                 zlog_info(
 175                                         "Neighbor %s (%s) going down: Kvalue mismatch",
 176                                         inet_ntoa(nbr->src),
 177                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 178                                                        VRF_DEFAULT));
 179                                 eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 180                         }
 181                 }
 182         }
 183
 184         return nbr;
 185 }
 186
 187 static uint8_t
 188 eigrp_hello_authentication_decode(struct stream *s,
 189                                   struct eigrp_tlv_hdr_type *tlv_header,
 190                                   struct eigrp_neighbor *nbr)
 191 {
 192         struct TLV_MD5_Authentication_Type *md5;
 193
 194         md5 = (struct TLV_MD5_Authentication_Type *)tlv_header;
 195
 196         if (md5->auth_type == EIGRP_AUTH_TYPE_MD5)
 197                 return eigrp_check_md5_digest(s, md5, nbr,
 198                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 199         else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256)
 200                 return eigrp_check_sha256_digest(
 201                         s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 202                         nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 203
 204         return 0;
 205 }
 206
 207 /**
 208  * @fn eigrp_sw_version_decode
 209  *
 210  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 211  * @param[in]           param   pointer to TLV software version information
 212  *
 213  * @return void
 214  *
 215  * @par
 216  * Read the software version in the specified location.
 217  * This consists of two bytes of OS version, and two bytes of EIGRP
 218  * revision number.
 219  */
 220 static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr,
 221                                     struct eigrp_tlv_hdr_type *tlv)
 222 {
 223         struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 224
 225         nbr->os_rel_major = version->vender_major;
 226         nbr->os_rel_minor = version->vender_minor;
 227         nbr->tlv_rel_major = version->eigrp_major;
 228         nbr->tlv_rel_minor = version->eigrp_minor;
 229         return;
 230 }
 231
 232 /**
 233  * @fn eigrp_peer_termination_decode
 234  *
 235  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 236  * @param[in]           tlv     pointer to TLV software version information
 237  *
 238  * @return void
 239  *
 240  * @par
 241  * Read the address in the TLV and match to out address. If
 242  * a match is found, move the sending neighbor to the down state. If
 243  * out address is not in the TLV, then ignore the peer termination
 244  */
 245 static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr,
 246                                           struct eigrp_tlv_hdr_type *tlv)
 247 {
 248         struct TLV_Peer_Termination_type *param =
 249                 (struct TLV_Peer_Termination_type *)tlv;
 250
 251         uint32_t my_ip = nbr->ei->address->u.prefix4.s_addr;
 252         uint32_t received_ip = param->neighbor_ip;
 253
 254         if (my_ip == received_ip) {
 255                 zlog_info("Neighbor %s (%s) is down: Peer Termination received",
 256                           inet_ntoa(nbr->src),
 257                           ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT));
 258                 /* set neighbor to DOWN */
 259                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 260                 /* delete neighbor */
 261                 eigrp_nbr_delete(nbr);
 262         }
 263 }
 264
 265 /**
 266  * @fn eigrp_peer_termination_encode
 267  *
 268  * @param[in,out]   s             packet stream TLV is stored to
 269  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 270  * Termination TLV
 271  *
 272  * @return uint16_t    number of bytes added to packet stream
 273  *
 274  * @par
 275  * Function used to encode Peer Termination TLV to Hello packet.
 276  */
 277 static uint16_t eigrp_peer_termination_encode(struct stream *s,
 278                                               struct in_addr *nbr_addr)
 279 {
 280         uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 281
 282         /* fill in type and length */
 283         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 284         stream_putw(s, length);
 285
 286         /* fill in unknown field 0x04 */
 287         stream_putc(s, 0x04);
 288
 289         /* finally neighbor IP address */
 290         stream_put_ipv4(s, nbr_addr->s_addr);
 291
 292         return (length);
 293 }
 294
 295 /*
 296  * @fn eigrp_hello_receive
 297  *
 298  * @param[in]   eigrp           eigrp routing process
 299  * @param[in]   iph             pointer to ip header
 300  * @param[in]   eigrph          pointer to eigrp header
 301  * @param[in]   s               input ip stream
 302  * @param[in]   ei              eigrp interface packet arrived on
 303  * @param[in]   size            size of eigrp packet
 304  *
 305  * @return void
 306  *
 307  * @par
 308  * This is the main worker function for processing hello packets. It
 309  * will validate the peer associated with the src ip address of the ip
 310  * header, and then decode each of the general TLVs which the packet
 311  * may contain.
 312  *
 313  * @usage
 314  * Not all TLVs are current decoder.  This is a work in progress..
 315  */
 316 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 317                          struct eigrp_header *eigrph, struct stream *s,
 318                          struct eigrp_interface *ei, int size)
 319 {
 320         struct eigrp_tlv_hdr_type *tlv_header;
 321         struct eigrp_neighbor *nbr;
 322         uint16_t type;
 323         uint16_t length;
 324
 325         /* get neighbor struct */
 326         nbr = eigrp_nbr_get(ei, eigrph, iph);
 327
 328         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 329         assert(nbr);
 330
 331         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 332                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%s)", size,
 333                            ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT),
 334                            inet_ntoa(nbr->src));
 335
 336         size -= EIGRP_HEADER_LEN;
 337         if (size < 0)
 338                 return;
 339
 340         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 341
 342         do {
 343                 type = ntohs(tlv_header->type);
 344                 length = ntohs(tlv_header->length);
 345
 346                 if ((length > 0) && (length <= size)) {
 347                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 348                                 zlog_debug(
 349                                         "  General TLV(%s)",
 350                                         lookup_msg(eigrp_general_tlv_type_str,
 351                                                    type, NULL));
 352
 353                         // determine what General TLV is being processed
 354                         switch (type) {
 355                         case EIGRP_TLV_PARAMETER:
 356                                 nbr = eigrp_hello_parameter_decode(nbr,
 357                                                                    tlv_header);
 358                                 if (!nbr)
 359                                         return;
 360                                 break;
 361                         case EIGRP_TLV_AUTH: {
 362                                 if (eigrp_hello_authentication_decode(
 363                                             s, tlv_header, nbr)
 364                                     == 0)
 365                                         return;
 366                                 else
 367                                         break;
 368                                 break;
 369                         }
 370                         case EIGRP_TLV_SEQ:
 371                                 break;
 372                         case EIGRP_TLV_SW_VERSION:
 373                                 eigrp_sw_version_decode(nbr, tlv_header);
 374                                 break;
 375                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 376                                 break;
 377                         case EIGRP_TLV_PEER_TERMINATION:
 378                                 eigrp_peer_termination_decode(nbr, tlv_header);
 379                                 return;
 380                                 break;
 381                         case EIGRP_TLV_PEER_MTRLIST:
 382                         case EIGRP_TLV_PEER_TIDLIST:
 383                                 break;
 384                         default:
 385                                 break;
 386                         }
 387                 }
 388
 389                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 390                                                            + length);
 391                 size -= length;
 392
 393         } while (size > 0);
 394
 395
 396         /*If received packet is hello with Parameter TLV*/
 397         if (ntohl(eigrph->ack) == 0) {
 398                 /* increment statistics. */
 399                 ei->hello_in++;
 400                 if (nbr)
 401                         eigrp_nbr_state_update(nbr);
 402         }
 403
 404         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 405                 zlog_debug("Hello Packet received from %s",
 406                            inet_ntoa(nbr->src));
 407 }
 408
 409 uint32_t FRR_MAJOR;
 410 uint32_t FRR_MINOR;
 411
 412 void eigrp_sw_version_initialize(void)
 413 {
 414         char ver_string[] = VERSION;
 415         char *dash = strstr(ver_string, "-");
 416         int ret;
 417
 418         if (dash)
 419                 dash[0] = '\0';
 420
 421         ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR,
 422                      &FRR_MINOR);
 423         if (ret != 2)
 424                 flog_err(EC_EIGRP_PACKET,
 425                          "Did not Properly parse %s, please fix VERSION string",
 426                          VERSION);
 427 }
 428
 429 /**
 430  * @fn eigrp_sw_version_encode
 431  *
 432  * @param[in,out]       s       packet stream TLV is stored to
 433  *
 434  * @return uint16_t     number of bytes added to packet stream
 435  *
 436  * @par
 437  * Store the software version in the specified location.
 438  * This consists of two bytes of OS version, and two bytes of EIGRP
 439  * revision number.
 440  */
 441 static uint16_t eigrp_sw_version_encode(struct stream *s)
 442 {
 443         uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 444
 445         // setup the tlv fields
 446         stream_putw(s, EIGRP_TLV_SW_VERSION);
 447         stream_putw(s, length);
 448
 449         stream_putc(s, FRR_MAJOR); //!< major os version
 450         stream_putc(s, FRR_MINOR); //!< minor os version
 451
 452         /* and the core eigrp version */
 453         stream_putc(s, EIGRP_MAJOR_VERSION);
 454         stream_putc(s, EIGRP_MINOR_VERSION);
 455
 456         return (length);
 457 }
 458
 459 /**
 460  * @fn eigrp_tidlist_encode
 461  *
 462  * @param[in,out]       s       packet stream TLV is stored to
 463  *
 464  * @return void
 465  *
 466  * @par
 467  * If doing mutli-topology, then store the supported TID list.
 468  * This is currently a place holder function
 469  */
 470 static uint16_t eigrp_tidlist_encode(struct stream *s)
 471 {
 472         // uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 473         return 0;
 474 }
 475
 476 /**
 477  * @fn eigrp_sequence_encode
 478  *
 479  * @param[in,out]       s       packet stream TLV is stored to
 480  *
 481  * @return uint16_t    number of bytes added to packet stream
 482  *
 483  * @par
 484  * Part of conditional receive process
 485  *
 486  */
 487 static uint16_t eigrp_sequence_encode(struct stream *s)
 488 {
 489         uint16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 490         struct eigrp *eigrp;
 491         struct eigrp_interface *ei;
 492         struct listnode *node, *node2, *nnode2;
 493         struct eigrp_neighbor *nbr;
 494         size_t backup_end, size_end;
 495         int found;
 496
 497         eigrp = eigrp_lookup();
 498         if (eigrp == NULL) {
 499                 return 0;
 500         }
 501
 502         // add in the parameters TLV
 503         backup_end = stream_get_endp(s);
 504         stream_putw(s, EIGRP_TLV_SEQ);
 505         size_end = s->endp;
 506         stream_putw(s, 0x0000);
 507         stream_putc(s, IPV4_MAX_BYTELEN);
 508
 509         found = 0;
 510         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 511                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 512                         if (nbr->multicast_queue->count > 0) {
 513                                 length += (uint16_t)stream_put_ipv4(
 514                                         s, nbr->src.s_addr);
 515                                 found = 1;
 516                         }
 517                 }
 518         }
 519
 520         if (found == 0) {
 521                 stream_set_endp(s, backup_end);
 522                 return 0;
 523         }
 524
 525         backup_end = stream_get_endp(s);
 526         stream_set_endp(s, size_end);
 527         stream_putw(s, length);
 528         stream_set_endp(s, backup_end);
 529
 530         return length;
 531 }
 532
 533 /**
 534  * @fn eigrp_sequence_encode
 535  *
 536  * @param[in,out]       s       packet stream TLV is stored to
 537  *
 538  * @return uint16_t    number of bytes added to packet stream
 539  *
 540  * @par
 541  * Part of conditional receive process
 542  *
 543  */
 544 static uint16_t eigrp_next_sequence_encode(struct stream *s)
 545 {
 546         uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 547         struct eigrp *eigrp;
 548
 549         eigrp = eigrp_lookup();
 550         if (eigrp == NULL) {
 551                 return 0;
 552         }
 553
 554         // add in the parameters TLV
 555         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 556         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 557         stream_putl(s, eigrp->sequence_number + 1);
 558
 559         return length;
 560 }
 561
 562 /**
 563  * @fn eigrp_hello_parameter_encode
 564  *
 565  * @param[in]           ei      pointer to interface hello packet came in on
 566  * @param[in,out]       s       packet stream TLV is stored to
 567  *
 568  * @return uint16_t     number of bytes added to packet stream
 569  *
 570  * @par
 571  * Encode Parameter TLV, used to convey metric weights and the hold time.
 572  *
 573  * @usage
 574  * Note the addition of K6 for the new extended metrics, and does not apply to
 575  * older TLV packet formats.
 576  */
 577 static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 578                                              struct stream *s, uint8_t flags)
 579 {
 580         uint16_t length = EIGRP_TLV_PARAMETER_LEN;
 581
 582         // add in the parameters TLV
 583         stream_putw(s, EIGRP_TLV_PARAMETER);
 584         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 585
 586         // if graceful shutdown is needed to be announced, send all 255 in K
 587         // values
 588         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 589                 stream_putc(s, 0xff); /* K1 */
 590                 stream_putc(s, 0xff); /* K2 */
 591                 stream_putc(s, 0xff); /* K3 */
 592                 stream_putc(s, 0xff); /* K4 */
 593                 stream_putc(s, 0xff); /* K5 */
 594                 stream_putc(s, 0xff); /* K6 */
 595         } else                        // set k values
 596         {
 597                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 598                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 599                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 600                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 601                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 602                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 603         }
 604
 605         // and set hold time value..
 606         stream_putw(s, ei->params.v_wait);
 607
 608         return length;
 609 }
 610
 611 /**
 612  * @fn eigrp_hello_encode
 613  *
 614  * @param[in]           ei      pointer to interface hello packet came in on
 615  * @param[in]           s       packet stream TLV is stored to
 616  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 617  * @param[in]           flags  type of hello packet
 618  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 619  * Termination TLV
 620  *
 621  * @return eigrp_packet         pointer initialize hello packet
 622  *
 623  * @par
 624  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 625  *
 626  */
 627 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 628                                                in_addr_t addr, uint32_t ack,
 629                                                uint8_t flags,
 630                                                struct in_addr *nbr_addr)
 631 {
 632         struct eigrp_packet *ep;
 633         uint16_t length = EIGRP_HEADER_LEN;
 634
 635         // allocate a new packet to be sent
 636         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL);
 637
 638         if (ep) {
 639                 // encode common header feilds
 640                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0,
 641                                          0, ack);
 642
 643                 // encode Authentication TLV
 644                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 645                     && (ei->params.auth_keychain != NULL)) {
 646                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 647                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 648                            && (ei->params.auth_keychain != NULL)) {
 649                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 650                 }
 651
 652                 /* encode appropriate parameters to Hello packet */
 653                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 654                         length += eigrp_hello_parameter_encode(
 655                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 656                 else
 657                         length += eigrp_hello_parameter_encode(
 658                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 659
 660                 // figure out the version of code we're running
 661                 length += eigrp_sw_version_encode(ep->s);
 662
 663                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 664                         length += eigrp_sequence_encode(ep->s);
 665                         length += eigrp_next_sequence_encode(ep->s);
 666                 }
 667
 668                 // add in the TID list if doing multi-topology
 669                 length += eigrp_tidlist_encode(ep->s);
 670
 671                 /* encode Peer Termination TLV if needed */
 672                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 673                         length +=
 674                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 675
 676                 // Set packet length
 677                 ep->length = length;
 678
 679                 // set soruce address for the hello packet
 680                 ep->dst.s_addr = addr;
 681
 682                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 683                     && (ei->params.auth_keychain != NULL)) {
 684                         eigrp_make_md5_digest(ei, ep->s,
 685                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 686                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 687                            && (ei->params.auth_keychain != NULL)) {
 688                         eigrp_make_sha256_digest(ei, ep->s,
 689                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 690                 }
 691
 692                 // EIGRP Checksum
 693                 eigrp_packet_checksum(ei, ep->s, length);
 694         }
 695
 696         return (ep);
 697 }
 698
 699 /**
 700  * @fn eigrp_hello_send
 701  *
 702  * @param[in]           nbr     neighbor the ACK should be sent to
 703  *
 704  * @return void
 705  *
 706  * @par
 707  *  Send (unicast) a hello packet with the destination address
 708  *  associated with the neighbor.  The eigrp header ACK feild will be
 709  *  updated to the neighbor's sequence number to acknolodge any
 710  *  outstanding packets
 711  */
 712 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 713 {
 714         struct eigrp_packet *ep;
 715
 716         /* if packet succesfully created, add it to the interface queue */
 717         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 718                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 719                                 NULL);
 720
 721         if (ep) {
 722                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 723                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%s]",
 724                                    nbr->recv_sequence_number,
 725                                    inet_ntoa(nbr->src));
 726
 727                 /* Add packet to the top of the interface output queue*/
 728                 eigrp_fifo_push(nbr->ei->obuf, ep);
 729
 730                 /* Hook thread to write packet. */
 731                 if (nbr->ei->on_write_q == 0) {
 732                         listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 733                         nbr->ei->on_write_q = 1;
 734                 }
 735                 thread_add_write(master, eigrp_write, nbr->ei->eigrp,
 736                                  nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write);
 737         }
 738 }
 739
 740 /**
 741  * @fn eigrp_hello_send
 742  *
 743  * @param[in]           ei      pointer to interface hello should be sent
 744  * @param[in]           flags type of hello packet
 745  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 746  * Termination TLV
 747  *
 748  * @return void
 749  *
 750  * @par
 751  * Build and enqueue a generic (multicast) periodic hello packet for
 752  * sending.  If no packets are currently queues, the packet will be
 753  * sent immadiatly
 754  */
 755 void eigrp_hello_send(struct eigrp_interface *ei, uint8_t flags,
 756                       struct in_addr *nbr_addr)
 757 {
 758         struct eigrp_packet *ep = NULL;
 759
 760         /* If this is passive interface, do not send EIGRP Hello.
 761            if ((EIGRP_IF_PASSIVE_STATUS (ei) == EIGRP_IF_PASSIVE) ||
 762            (ei->type != EIGRP_IFTYPE_NBMA))
 763            return;
 764         */
 765
 766         if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 767                 zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 768
 769         /* if packet was succesfully created, then add it to the interface queue
 770          */
 771         ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags,
 772                                 nbr_addr);
 773
 774         if (ep) {
 775                 // Add packet to the top of the interface output queue
 776                 eigrp_fifo_push(ei->obuf, ep);
 777
 778                 /* Hook thread to write packet. */
 779                 if (ei->on_write_q == 0) {
 780                         listnode_add(ei->eigrp->oi_write_q, ei);
 781                         ei->on_write_q = 1;
 782                 }
 783
 784                 if (ei->eigrp->t_write == NULL) {
 785                         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 786                                 thread_execute(master, eigrp_write, ei->eigrp,
 787                                                ei->eigrp->fd);
 788                         } else {
 789                                 thread_add_write(master, eigrp_write, ei->eigrp,
 790                                                  ei->eigrp->fd,
 791                                                  &ei->eigrp->t_write);
 792                         }
 793                 }
 794         }
 795 }