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
  58 /* Packet Type String. */
  59 static const struct message eigrp_general_tlv_type_str[] = {
  60         {EIGRP_TLV_PARAMETER, "PARAMETER"},
  61         {EIGRP_TLV_AUTH, "AUTH"},
  62         {EIGRP_TLV_SEQ, "SEQ"},
  63         {EIGRP_TLV_SW_VERSION, "SW_VERSION"},
  64         {EIGRP_TLV_NEXT_MCAST_SEQ, "NEXT_MCAST_SEQ"},
  65         {EIGRP_TLV_PEER_TERMINATION, "PEER_TERMINATION"},
  66         {EIGRP_TLV_PEER_MTRLIST, "PEER_MTRLIST"},
  67         {EIGRP_TLV_PEER_TIDLIST, "PEER_TIDLIST"},
  68         {0}};
  69
  70
  71 /*
  72  * @fn eigrp_hello_timer
  73  *
  74  * @param[in]   thread  current execution thread timer is associated with
  75  *
  76  * @return int  always returns 0
  77  *
  78  * @par
  79  * Called once per "hello" time interval, default 5 seconds
  80  * Sends hello packet via multicast for all interfaces eigrp
  81  * is configured for
  82  */
  83 int eigrp_hello_timer(struct thread *thread)
  84 {
  85         struct eigrp_interface *ei;
  86
  87         ei = THREAD_ARG(thread);
  88         ei->t_hello = NULL;
  89
  90         if (IS_DEBUG_EIGRP(0, TIMERS))
  91                 zlog_debug("Start Hello Timer (%s) Expire [%u]", IF_NAME(ei),
  92                            EIGRP_IF_PARAM(ei, v_hello));
  93
  94         /* Sending hello packet. */
  95         eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL);
  96
  97         /* Hello timer set. */
  98         ei->t_hello = NULL;
  99         thread_add_timer(master, eigrp_hello_timer, ei,
 100                          EIGRP_IF_PARAM(ei, v_hello), &ei->t_hello);
 101
 102         return 0;
 103 }
 104
 105 /**
 106  * @fn eigrp_hello_parameter_decode
 107  *
 108  * @param[in]           nbr     neighbor the ACK should be sent to
 109  * @param[in]           param   pointer packet TLV is stored to
 110  *
 111  * @return u_int16_t    number of bytes added to packet stream
 112  *
 113  * @par
 114  * Encode Parameter TLV, used to convey metric weights and the hold time.
 115  *
 116  * @usage
 117  * Note the addition of K6 for the new extended metrics, and does not apply to
 118  * older TLV packet formats.
 119  */
 120 static struct eigrp_neighbor *
 121 eigrp_hello_parameter_decode(struct eigrp_neighbor *nbr,
 122                              struct eigrp_tlv_hdr_type *tlv)
 123 {
 124         struct eigrp *eigrp = nbr->ei->eigrp;
 125         struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv;
 126
 127         /* copy over the values passed in by the neighbor */
 128         nbr->K1 = param->K1;
 129         nbr->K2 = param->K2;
 130         nbr->K3 = param->K3;
 131         nbr->K4 = param->K4;
 132         nbr->K5 = param->K5;
 133         nbr->K6 = param->K6;
 134         nbr->v_holddown = ntohs(param->hold_time);
 135
 136         /*
 137          * Check K1-K5 have the correct values to be able to become neighbors
 138          * K6 does not have to match
 139          */
 140         if ((eigrp->k_values[0] == nbr->K1) && (eigrp->k_values[1] == nbr->K2)
 141             && (eigrp->k_values[2] == nbr->K3)
 142             && (eigrp->k_values[3] == nbr->K4)
 143             && (eigrp->k_values[4] == nbr->K5)) {
 144
 145                 if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN) {
 146                         zlog_info("Neighbor %s (%s) is pending: new adjacency",
 147                                   inet_ntoa(nbr->src),
 148                                   ifindex2ifname(nbr->ei->ifp->ifindex,
 149                                                  VRF_DEFAULT));
 150
 151                         /* Expedited hello sent */
 152                         eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL);
 153
 154                         //     if(ntohl(nbr->ei->address->u.prefix4.s_addr) >
 155                         //     ntohl(nbr->src.s_addr))
 156                         eigrp_update_send_init(nbr);
 157
 158                         eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 159                 }
 160         } else {
 161                 if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN) {
 162                         if ((param->K1 & param->K2 & param->K3 & param->K4
 163                              & param->K5)
 164                             == 255) {
 165                                 zlog_info(
 166                                         "Neighbor %s (%s) is down: Interface PEER-TERMINATION received",
 167                                         inet_ntoa(nbr->src),
 168                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 169                                                        VRF_DEFAULT));
 170                                 eigrp_nbr_delete(nbr);
 171                                 return NULL;
 172                         } else {
 173                                 zlog_info(
 174                                         "Neighbor %s (%s) going down: Kvalue mismatch",
 175                                         inet_ntoa(nbr->src),
 176                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 177                                                        VRF_DEFAULT));
 178                                 eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 179                         }
 180                 }
 181         }
 182
 183         return nbr;
 184 }
 185
 186 static u_char
 187 eigrp_hello_authentication_decode(struct stream *s,
 188                                   struct eigrp_tlv_hdr_type *tlv_header,
 189                                   struct eigrp_neighbor *nbr)
 190 {
 191         struct TLV_MD5_Authentication_Type *md5;
 192
 193         md5 = (struct TLV_MD5_Authentication_Type *)tlv_header;
 194
 195         if (md5->auth_type == EIGRP_AUTH_TYPE_MD5)
 196                 return eigrp_check_md5_digest(s, md5, nbr,
 197                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 198         else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256)
 199                 return eigrp_check_sha256_digest(
 200                         s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 201                         nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 202
 203         return 0;
 204 }
 205
 206 /**
 207  * @fn eigrp_sw_version_decode
 208  *
 209  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 210  * @param[in]           param   pointer to TLV software version information
 211  *
 212  * @return void
 213  *
 214  * @par
 215  * Read the software version in the specified location.
 216  * This consists of two bytes of OS version, and two bytes of EIGRP
 217  * revision number.
 218  */
 219 static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr,
 220                                     struct eigrp_tlv_hdr_type *tlv)
 221 {
 222         struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 223
 224         nbr->os_rel_major = version->vender_major;
 225         nbr->os_rel_minor = version->vender_minor;
 226         nbr->tlv_rel_major = version->eigrp_major;
 227         nbr->tlv_rel_minor = version->eigrp_minor;
 228         return;
 229 }
 230
 231 /**
 232  * @fn eigrp_peer_termination_decode
 233  *
 234  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 235  * @param[in]           tlv     pointer to TLV software version information
 236  *
 237  * @return void
 238  *
 239  * @par
 240  * Read the address in the TLV and match to out address. If
 241  * a match is found, move the sending neighbor to the down state. If
 242  * out address is not in the TLV, then ignore the peer termination
 243  */
 244 static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr,
 245                                           struct eigrp_tlv_hdr_type *tlv)
 246 {
 247         struct TLV_Peer_Termination_type *param =
 248                 (struct TLV_Peer_Termination_type *)tlv;
 249
 250         uint32_t my_ip = nbr->ei->address->u.prefix4.s_addr;
 251         uint32_t received_ip = param->neighbor_ip;
 252
 253         if (my_ip == received_ip) {
 254                 zlog_info("Neighbor %s (%s) is down: Peer Termination received",
 255                           inet_ntoa(nbr->src),
 256                           ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT));
 257                 /* set neighbor to DOWN */
 258                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 259                 /* delete neighbor */
 260                 eigrp_nbr_delete(nbr);
 261         }
 262 }
 263
 264 /**
 265  * @fn eigrp_peer_termination_encode
 266  *
 267  * @param[in,out]   s             packet stream TLV is stored to
 268  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 269  * Termination TLV
 270  *
 271  * @return u_int16_t    number of bytes added to packet stream
 272  *
 273  * @par
 274  * Function used to encode Peer Termination TLV to Hello packet.
 275  */
 276 static u_int16_t eigrp_peer_termination_encode(struct stream *s,
 277                                                struct in_addr *nbr_addr)
 278 {
 279         u_int16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 280
 281         /* fill in type and length */
 282         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 283         stream_putw(s, length);
 284
 285         /* fill in unknown field 0x04 */
 286         stream_putc(s, 0x04);
 287
 288         /* finally neighbor IP address */
 289         stream_put_ipv4(s, nbr_addr->s_addr);
 290
 291         return (length);
 292 }
 293
 294 /*
 295  * @fn eigrp_hello_receive
 296  *
 297  * @param[in]   eigrp           eigrp routing process
 298  * @param[in]   iph             pointer to ip header
 299  * @param[in]   eigrph          pointer to eigrp header
 300  * @param[in]   s               input ip stream
 301  * @param[in]   ei              eigrp interface packet arrived on
 302  * @param[in]   size            size of eigrp packet
 303  *
 304  * @return void
 305  *
 306  * @par
 307  * This is the main worker function for processing hello packets. It
 308  * will validate the peer associated with the src ip address of the ip
 309  * header, and then decode each of the general TLVs which the packet
 310  * may contain.
 311  *
 312  * @usage
 313  * Not all TLVs are current decoder.  This is a work in progress..
 314  */
 315 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 316                          struct eigrp_header *eigrph, struct stream *s,
 317                          struct eigrp_interface *ei, int size)
 318 {
 319         struct eigrp_tlv_hdr_type *tlv_header;
 320         struct eigrp_neighbor *nbr;
 321         uint16_t type;
 322         uint16_t length;
 323
 324         /* get neighbor struct */
 325         nbr = eigrp_nbr_get(ei, eigrph, iph);
 326
 327         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 328         assert(nbr);
 329
 330         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 331                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%s)", size,
 332                            ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT),
 333                            inet_ntoa(nbr->src));
 334
 335         size -= EIGRP_HEADER_LEN;
 336         if (size < 0)
 337                 return;
 338
 339         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 340
 341         do {
 342                 type = ntohs(tlv_header->type);
 343                 length = ntohs(tlv_header->length);
 344
 345                 if ((length > 0) && (length <= size)) {
 346                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 347                                 zlog_debug(
 348                                         "  General TLV(%s)",
 349                                         lookup_msg(eigrp_general_tlv_type_str,
 350                                                    type, NULL));
 351
 352                         // determine what General TLV is being processed
 353                         switch (type) {
 354                         case EIGRP_TLV_PARAMETER:
 355                                 nbr = eigrp_hello_parameter_decode(nbr,
 356                                                                    tlv_header);
 357                                 if (!nbr)
 358                                         return;
 359                                 break;
 360                         case EIGRP_TLV_AUTH: {
 361                                 if (eigrp_hello_authentication_decode(
 362                                             s, tlv_header, nbr)
 363                                     == 0)
 364                                         return;
 365                                 else
 366                                         break;
 367                                 break;
 368                         }
 369                         case EIGRP_TLV_SEQ:
 370                                 break;
 371                         case EIGRP_TLV_SW_VERSION:
 372                                 eigrp_sw_version_decode(nbr, tlv_header);
 373                                 break;
 374                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 375                                 break;
 376                         case EIGRP_TLV_PEER_TERMINATION:
 377                                 eigrp_peer_termination_decode(nbr, tlv_header);
 378                                 return;
 379                                 break;
 380                         case EIGRP_TLV_PEER_MTRLIST:
 381                         case EIGRP_TLV_PEER_TIDLIST:
 382                                 break;
 383                         default:
 384                                 break;
 385                         }
 386                 }
 387
 388                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 389                                                            + length);
 390                 size -= length;
 391
 392         } while (size > 0);
 393
 394
 395         /*If received packet is hello with Parameter TLV*/
 396         if (ntohl(eigrph->ack) == 0) {
 397                 /* increment statistics. */
 398                 ei->hello_in++;
 399                 if (nbr)
 400                         eigrp_nbr_state_update(nbr);
 401         }
 402
 403         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 404                 zlog_debug("Hello Packet received from %s",
 405                            inet_ntoa(nbr->src));
 406 }
 407
 408 /**
 409  * @fn eigrp_sw_version_encode
 410  *
 411  * @param[in,out]       s       packet stream TLV is stored to
 412  *
 413  * @return u_int16_t    number of bytes added to packet stream
 414  *
 415  * @par
 416  * Store the software version in the specified location.
 417  * This consists of two bytes of OS version, and two bytes of EIGRP
 418  * revision number.
 419  */
 420 static u_int16_t eigrp_sw_version_encode(struct stream *s)
 421 {
 422         u_int16_t length = EIGRP_TLV_SW_VERSION_LEN;
 423
 424         // setup the tlv fields
 425         stream_putw(s, EIGRP_TLV_SW_VERSION);
 426         stream_putw(s, length);
 427
 428         // encode the version of quagga we're running
 429         // DVS: need to figure out a cleaner way to do this
 430         stream_putc(s, 0);  //!< major os version
 431         stream_putc(s, 99); //!< minor os version
 432
 433         /* and the core eigrp version */
 434         stream_putc(s, EIGRP_MAJOR_VERSION);
 435         stream_putc(s, EIGRP_MINOR_VERSION);
 436
 437         return (length);
 438 }
 439
 440 /**
 441  * @fn eigrp_tidlist_encode
 442  *
 443  * @param[in,out]       s       packet stream TLV is stored to
 444  *
 445  * @return void
 446  *
 447  * @par
 448  * If doing mutli-topology, then store the supported TID list.
 449  * This is currently a place holder function
 450  */
 451 static u_int16_t eigrp_tidlist_encode(struct stream *s)
 452 {
 453         // u_int16_t length = EIGRP_TLV_SW_VERSION_LEN;
 454         return 0;
 455 }
 456
 457 /**
 458  * @fn eigrp_sequence_encode
 459  *
 460  * @param[in,out]       s       packet stream TLV is stored to
 461  *
 462  * @return u_int16_t    number of bytes added to packet stream
 463  *
 464  * @par
 465  * Part of conditional receive process
 466  *
 467  */
 468 static u_int16_t eigrp_sequence_encode(struct stream *s)
 469 {
 470         u_int16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 471         struct eigrp *eigrp;
 472         struct eigrp_interface *ei;
 473         struct listnode *node, *node2, *nnode2;
 474         struct eigrp_neighbor *nbr;
 475         size_t backup_end, size_end;
 476         int found;
 477
 478         eigrp = eigrp_lookup();
 479         if (eigrp == NULL) {
 480                 return 0;
 481         }
 482
 483         // add in the parameters TLV
 484         backup_end = stream_get_endp(s);
 485         stream_putw(s, EIGRP_TLV_SEQ);
 486         size_end = s->endp;
 487         stream_putw(s, 0x0000);
 488         stream_putc(s, IPV4_MAX_BYTELEN);
 489
 490         found = 0;
 491         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 492                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 493                         if (nbr->multicast_queue->count > 0) {
 494                                 length += (u_int16_t)stream_put_ipv4(
 495                                         s, nbr->src.s_addr);
 496                                 found = 1;
 497                         }
 498                 }
 499         }
 500
 501         if (found == 0) {
 502                 stream_set_endp(s, backup_end);
 503                 return 0;
 504         }
 505
 506         backup_end = stream_get_endp(s);
 507         stream_set_endp(s, size_end);
 508         stream_putw(s, length);
 509         stream_set_endp(s, backup_end);
 510
 511         return length;
 512 }
 513
 514 /**
 515  * @fn eigrp_sequence_encode
 516  *
 517  * @param[in,out]       s       packet stream TLV is stored to
 518  *
 519  * @return u_int16_t    number of bytes added to packet stream
 520  *
 521  * @par
 522  * Part of conditional receive process
 523  *
 524  */
 525 static u_int16_t eigrp_next_sequence_encode(struct stream *s)
 526 {
 527         u_int16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 528         struct eigrp *eigrp;
 529
 530         eigrp = eigrp_lookup();
 531         if (eigrp == NULL) {
 532                 return 0;
 533         }
 534
 535         // add in the parameters TLV
 536         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 537         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 538         stream_putl(s, eigrp->sequence_number + 1);
 539
 540         return length;
 541 }
 542
 543 /**
 544  * @fn eigrp_hello_parameter_encode
 545  *
 546  * @param[in]           ei      pointer to interface hello packet came in on
 547  * @param[in,out]       s       packet stream TLV is stored to
 548  *
 549  * @return u_int16_t    number of bytes added to packet stream
 550  *
 551  * @par
 552  * Encode Parameter TLV, used to convey metric weights and the hold time.
 553  *
 554  * @usage
 555  * Note the addition of K6 for the new extended metrics, and does not apply to
 556  * older TLV packet formats.
 557  */
 558 static u_int16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 559                                               struct stream *s, u_char flags)
 560 {
 561         u_int16_t length = EIGRP_TLV_PARAMETER_LEN;
 562
 563         // add in the parameters TLV
 564         stream_putw(s, EIGRP_TLV_PARAMETER);
 565         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 566
 567         // if graceful shutdown is needed to be announced, send all 255 in K
 568         // values
 569         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 570                 stream_putc(s, 0xff); /* K1 */
 571                 stream_putc(s, 0xff); /* K2 */
 572                 stream_putc(s, 0xff); /* K3 */
 573                 stream_putc(s, 0xff); /* K4 */
 574                 stream_putc(s, 0xff); /* K5 */
 575                 stream_putc(s, 0xff); /* K6 */
 576         } else                        // set k values
 577         {
 578                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 579                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 580                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 581                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 582                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 583                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 584         }
 585
 586         // and set hold time value..
 587         stream_putw(s, IF_DEF_PARAMS(ei->ifp)->v_wait);
 588
 589         return length;
 590 }
 591
 592 /**
 593  * @fn eigrp_hello_encode
 594  *
 595  * @param[in]           ei      pointer to interface hello packet came in on
 596  * @param[in]           s       packet stream TLV is stored to
 597  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 598  * @param[in]           flags  type of hello packet
 599  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 600  * Termination TLV
 601  *
 602  * @return eigrp_packet         pointer initialize hello packet
 603  *
 604  * @par
 605  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 606  *
 607  */
 608 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 609                                                in_addr_t addr, u_int32_t ack,
 610                                                u_char flags,
 611                                                struct in_addr *nbr_addr)
 612 {
 613         struct eigrp_packet *ep;
 614         u_int16_t length = EIGRP_HEADER_LEN;
 615
 616         // allocate a new packet to be sent
 617         ep = eigrp_packet_new(ei->ifp->mtu);
 618
 619         if (ep) {
 620                 // encode common header feilds
 621                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei, ep->s, 0, 0, ack);
 622
 623                 // encode Authentication TLV
 624                 if ((IF_DEF_PARAMS(ei->ifp)->auth_type == EIGRP_AUTH_TYPE_MD5)
 625                     && (IF_DEF_PARAMS(ei->ifp)->auth_keychain != NULL)) {
 626                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 627                 } else if ((IF_DEF_PARAMS(ei->ifp)->auth_type
 628                             == EIGRP_AUTH_TYPE_SHA256)
 629                            && (IF_DEF_PARAMS(ei->ifp)->auth_keychain != NULL)) {
 630                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 631                 }
 632
 633                 /* encode appropriate parameters to Hello packet */
 634                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 635                         length += eigrp_hello_parameter_encode(
 636                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 637                 else
 638                         length += eigrp_hello_parameter_encode(
 639                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 640
 641                 // figure out the version of code we're running
 642                 length += eigrp_sw_version_encode(ep->s);
 643
 644                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 645                         length += eigrp_sequence_encode(ep->s);
 646                         length += eigrp_next_sequence_encode(ep->s);
 647                 }
 648
 649                 // add in the TID list if doing multi-topology
 650                 length += eigrp_tidlist_encode(ep->s);
 651
 652                 /* encode Peer Termination TLV if needed */
 653                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 654                         length +=
 655                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 656
 657                 // Set packet length
 658                 ep->length = length;
 659
 660                 // set soruce address for the hello packet
 661                 ep->dst.s_addr = addr;
 662
 663                 if ((IF_DEF_PARAMS(ei->ifp)->auth_type == EIGRP_AUTH_TYPE_MD5)
 664                     && (IF_DEF_PARAMS(ei->ifp)->auth_keychain != NULL)) {
 665                         eigrp_make_md5_digest(ei, ep->s,
 666                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 667                 } else if ((IF_DEF_PARAMS(ei->ifp)->auth_type
 668                             == EIGRP_AUTH_TYPE_SHA256)
 669                            && (IF_DEF_PARAMS(ei->ifp)->auth_keychain != NULL)) {
 670                         eigrp_make_sha256_digest(ei, ep->s,
 671                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 672                 }
 673
 674                 // EIGRP Checksum
 675                 eigrp_packet_checksum(ei, ep->s, length);
 676         }
 677
 678         return (ep);
 679 }
 680
 681 /**
 682  * @fn eigrp_hello_send
 683  *
 684  * @param[in]           nbr     neighbor the ACK should be sent to
 685  *
 686  * @return void
 687  *
 688  * @par
 689  *  Send (unicast) a hello packet with the destination address
 690  *  associated with the neighbor.  The eigrp header ACK feild will be
 691  *  updated to the neighbor's sequence number to acknolodge any
 692  *  outstanding packets
 693  */
 694 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 695 {
 696         struct eigrp_packet *ep;
 697
 698         /* if packet succesfully created, add it to the interface queue */
 699         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 700                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 701                                 NULL);
 702
 703         if (ep) {
 704                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 705                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%s]",
 706                                    nbr->recv_sequence_number,
 707                                    inet_ntoa(nbr->src));
 708
 709                 /* Add packet to the top of the interface output queue*/
 710                 eigrp_fifo_push_head(nbr->ei->obuf, ep);
 711
 712                 /* Hook thread to write packet. */
 713                 if (nbr->ei->on_write_q == 0) {
 714                         listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 715                         nbr->ei->on_write_q = 1;
 716                 }
 717                 thread_add_write(master, eigrp_write, nbr->ei->eigrp,
 718                                  nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write);
 719         }
 720 }
 721
 722 /**
 723  * @fn eigrp_hello_send
 724  *
 725  * @param[in]           ei      pointer to interface hello should be sent
 726  * @param[in]           flags type of hello packet
 727  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 728  * Termination TLV
 729  *
 730  * @return void
 731  *
 732  * @par
 733  * Build and enqueue a generic (multicast) periodic hello packet for
 734  * sending.  If no packets are currently queues, the packet will be
 735  * sent immadiatly
 736  */
 737 void eigrp_hello_send(struct eigrp_interface *ei, u_char flags,
 738                       struct in_addr *nbr_addr)
 739 {
 740         struct eigrp_packet *ep = NULL;
 741
 742         /* If this is passive interface, do not send EIGRP Hello.
 743            if ((EIGRP_IF_PASSIVE_STATUS (ei) == EIGRP_IF_PASSIVE) ||
 744            (ei->type != EIGRP_IFTYPE_NBMA))
 745            return;
 746         */
 747
 748         if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 749                 zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 750
 751         /* if packet was succesfully created, then add it to the interface queue
 752          */
 753         ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags,
 754                                 nbr_addr);
 755
 756         if (ep) {
 757                 // Add packet to the top of the interface output queue
 758                 eigrp_fifo_push_head(ei->obuf, ep);
 759
 760                 /* Hook thread to write packet. */
 761                 if (ei->on_write_q == 0) {
 762                         listnode_add(ei->eigrp->oi_write_q, ei);
 763                         ei->on_write_q = 1;
 764                 }
 765
 766                 if (ei->eigrp->t_write == NULL) {
 767                         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 768                                 thread_execute(master, eigrp_write, ei->eigrp,
 769                                                ei->eigrp->fd);
 770                         } else {
 771                                 thread_add_write(master, eigrp_write, ei->eigrp,
 772                                                  ei->eigrp->fd,
 773                                                  &ei->eigrp->t_write);
 774                         }
 775                 }
 776         }
 777 }