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(
 148                                 "Neighbor %pI4 (%s) is pending: new adjacency",
 149                                 &nbr->src,
 150                                 ifindex2ifname(nbr->ei->ifp->ifindex,
 151                                                eigrp->vrf_id));
 152
 153                         /* Expedited hello sent */
 154                         eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL);
 155
 156                         //     if(ntohl(nbr->ei->address->u.prefix4.s_addr) >
 157                         //     ntohl(nbr->src.s_addr))
 158                         eigrp_update_send_init(nbr);
 159
 160                         eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 161                 }
 162         } else {
 163                 if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN) {
 164                         if ((param->K1 & param->K2 & param->K3 & param->K4
 165                              & param->K5)
 166                             == 255) {
 167                                 zlog_info(
 168                                         "Neighbor %pI4 (%s) is down: Interface PEER-TERMINATION received",
 169                                         &nbr->src,
 170                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 171                                                        eigrp->vrf_id));
 172                                 eigrp_nbr_delete(nbr);
 173                                 return NULL;
 174                         } else {
 175                                 zlog_info(
 176                                         "Neighbor %pI4 (%s) going down: Kvalue mismatch",
 177                                         &nbr->src,
 178                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 179                                                        eigrp->vrf_id));
 180                                 eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 181                         }
 182                 }
 183         }
 184
 185         return nbr;
 186 }
 187
 188 static uint8_t
 189 eigrp_hello_authentication_decode(struct stream *s,
 190                                   struct eigrp_tlv_hdr_type *tlv_header,
 191                                   struct eigrp_neighbor *nbr)
 192 {
 193         struct TLV_MD5_Authentication_Type *md5;
 194
 195         md5 = (struct TLV_MD5_Authentication_Type *)tlv_header;
 196
 197         if (md5->auth_type == EIGRP_AUTH_TYPE_MD5)
 198                 return eigrp_check_md5_digest(s, md5, nbr,
 199                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 200         else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256)
 201                 return eigrp_check_sha256_digest(
 202                         s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 203                         nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 204
 205         return 0;
 206 }
 207
 208 /**
 209  * @fn eigrp_sw_version_decode
 210  *
 211  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 212  * @param[in]           param   pointer to TLV software version information
 213  *
 214  * @return void
 215  *
 216  * @par
 217  * Read the software version in the specified location.
 218  * This consists of two bytes of OS version, and two bytes of EIGRP
 219  * revision number.
 220  */
 221 static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr,
 222                                     struct eigrp_tlv_hdr_type *tlv)
 223 {
 224         struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 225
 226         nbr->os_rel_major = version->vender_major;
 227         nbr->os_rel_minor = version->vender_minor;
 228         nbr->tlv_rel_major = version->eigrp_major;
 229         nbr->tlv_rel_minor = version->eigrp_minor;
 230         return;
 231 }
 232
 233 /**
 234  * @fn eigrp_peer_termination_decode
 235  *
 236  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 237  * @param[in]           tlv     pointer to TLV software version information
 238  *
 239  * @return void
 240  *
 241  * @par
 242  * Read the address in the TLV and match to out address. If
 243  * a match is found, move the sending neighbor to the down state. If
 244  * out address is not in the TLV, then ignore the peer termination
 245  */
 246 static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr,
 247                                           struct eigrp_tlv_hdr_type *tlv)
 248 {
 249         struct eigrp *eigrp = nbr->ei->eigrp;
 250         struct TLV_Peer_Termination_type *param =
 251                 (struct TLV_Peer_Termination_type *)tlv;
 252
 253         uint32_t my_ip = nbr->ei->address.u.prefix4.s_addr;
 254         uint32_t received_ip = param->neighbor_ip;
 255
 256         if (my_ip == received_ip) {
 257                 zlog_info(
 258                         "Neighbor %pI4 (%s) is down: Peer Termination received",
 259                         &nbr->src,
 260                         ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id));
 261                 /* set neighbor to DOWN */
 262                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 263                 /* delete neighbor */
 264                 eigrp_nbr_delete(nbr);
 265         }
 266 }
 267
 268 /**
 269  * @fn eigrp_peer_termination_encode
 270  *
 271  * @param[in,out]   s             packet stream TLV is stored to
 272  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 273  * Termination TLV
 274  *
 275  * @return uint16_t    number of bytes added to packet stream
 276  *
 277  * @par
 278  * Function used to encode Peer Termination TLV to Hello packet.
 279  */
 280 static uint16_t eigrp_peer_termination_encode(struct stream *s,
 281                                               struct in_addr *nbr_addr)
 282 {
 283         uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 284
 285         /* fill in type and length */
 286         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 287         stream_putw(s, length);
 288
 289         /* fill in unknown field 0x04 */
 290         stream_putc(s, 0x04);
 291
 292         /* finally neighbor IP address */
 293         stream_put_ipv4(s, nbr_addr->s_addr);
 294
 295         return (length);
 296 }
 297
 298 /*
 299  * @fn eigrp_hello_receive
 300  *
 301  * @param[in]   eigrp           eigrp routing process
 302  * @param[in]   iph             pointer to ip header
 303  * @param[in]   eigrph          pointer to eigrp header
 304  * @param[in]   s               input ip stream
 305  * @param[in]   ei              eigrp interface packet arrived on
 306  * @param[in]   size            size of eigrp packet
 307  *
 308  * @return void
 309  *
 310  * @par
 311  * This is the main worker function for processing hello packets. It
 312  * will validate the peer associated with the src ip address of the ip
 313  * header, and then decode each of the general TLVs which the packet
 314  * may contain.
 315  *
 316  * @usage
 317  * Not all TLVs are current decoder.  This is a work in progress..
 318  */
 319 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 320                          struct eigrp_header *eigrph, struct stream *s,
 321                          struct eigrp_interface *ei, int size)
 322 {
 323         struct eigrp_tlv_hdr_type *tlv_header;
 324         struct eigrp_neighbor *nbr;
 325         uint16_t type;
 326         uint16_t length;
 327
 328         /* get neighbor struct */
 329         nbr = eigrp_nbr_get(ei, eigrph, iph);
 330
 331         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 332         assert(nbr);
 333
 334         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 335                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%pI4)", size,
 336                            ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id),
 337                            &nbr->src);
 338
 339         size -= EIGRP_HEADER_LEN;
 340         if (size < 0)
 341                 return;
 342
 343         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 344
 345         do {
 346                 type = ntohs(tlv_header->type);
 347                 length = ntohs(tlv_header->length);
 348
 349                 if ((length > 0) && (length <= size)) {
 350                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 351                                 zlog_debug(
 352                                         "  General TLV(%s)",
 353                                         lookup_msg(eigrp_general_tlv_type_str,
 354                                                    type, NULL));
 355
 356                         // determine what General TLV is being processed
 357                         switch (type) {
 358                         case EIGRP_TLV_PARAMETER:
 359                                 nbr = eigrp_hello_parameter_decode(nbr,
 360                                                                    tlv_header);
 361                                 if (!nbr)
 362                                         return;
 363                                 break;
 364                         case EIGRP_TLV_AUTH: {
 365                                 if (eigrp_hello_authentication_decode(
 366                                             s, tlv_header, nbr)
 367                                     == 0)
 368                                         return;
 369                                 else
 370                                         break;
 371                                 break;
 372                         }
 373                         case EIGRP_TLV_SEQ:
 374                                 break;
 375                         case EIGRP_TLV_SW_VERSION:
 376                                 eigrp_sw_version_decode(nbr, tlv_header);
 377                                 break;
 378                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 379                                 break;
 380                         case EIGRP_TLV_PEER_TERMINATION:
 381                                 eigrp_peer_termination_decode(nbr, tlv_header);
 382                                 return;
 383                                 break;
 384                         case EIGRP_TLV_PEER_MTRLIST:
 385                         case EIGRP_TLV_PEER_TIDLIST:
 386                                 break;
 387                         default:
 388                                 break;
 389                         }
 390                 }
 391
 392                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 393                                                            + length);
 394                 size -= length;
 395
 396         } while (size > 0);
 397
 398
 399         /*If received packet is hello with Parameter TLV*/
 400         if (ntohl(eigrph->ack) == 0) {
 401                 /* increment statistics. */
 402                 ei->hello_in++;
 403                 if (nbr)
 404                         eigrp_nbr_state_update(nbr);
 405         }
 406
 407         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 408                 zlog_debug("Hello Packet received from %pI4", &nbr->src);
 409 }
 410
 411 uint32_t FRR_MAJOR;
 412 uint32_t FRR_MINOR;
 413
 414 void eigrp_sw_version_initialize(void)
 415 {
 416         char ver_string[] = VERSION;
 417         char *dash = strstr(ver_string, "-");
 418         int ret;
 419
 420         if (dash)
 421                 dash[0] = '\0';
 422
 423         ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR,
 424                      &FRR_MINOR);
 425         if (ret != 2)
 426                 flog_err(EC_EIGRP_PACKET,
 427                          "Did not Properly parse %s, please fix VERSION string",
 428                          VERSION);
 429 }
 430
 431 /**
 432  * @fn eigrp_sw_version_encode
 433  *
 434  * @param[in,out]       s       packet stream TLV is stored to
 435  *
 436  * @return uint16_t     number of bytes added to packet stream
 437  *
 438  * @par
 439  * Store the software version in the specified location.
 440  * This consists of two bytes of OS version, and two bytes of EIGRP
 441  * revision number.
 442  */
 443 static uint16_t eigrp_sw_version_encode(struct stream *s)
 444 {
 445         uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 446
 447         // setup the tlv fields
 448         stream_putw(s, EIGRP_TLV_SW_VERSION);
 449         stream_putw(s, length);
 450
 451         stream_putc(s, FRR_MAJOR); //!< major os version
 452         stream_putc(s, FRR_MINOR); //!< minor os version
 453
 454         /* and the core eigrp version */
 455         stream_putc(s, EIGRP_MAJOR_VERSION);
 456         stream_putc(s, EIGRP_MINOR_VERSION);
 457
 458         return (length);
 459 }
 460
 461 /**
 462  * @fn eigrp_tidlist_encode
 463  *
 464  * @param[in,out]       s       packet stream TLV is stored to
 465  *
 466  * @return void
 467  *
 468  * @par
 469  * If doing mutli-topology, then store the supported TID list.
 470  * This is currently a place holder function
 471  */
 472 static uint16_t eigrp_tidlist_encode(struct stream *s)
 473 {
 474         // uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 475         return 0;
 476 }
 477
 478 /**
 479  * @fn eigrp_sequence_encode
 480  *
 481  * @param[in,out]       s       packet stream TLV is stored to
 482  *
 483  * @return uint16_t    number of bytes added to packet stream
 484  *
 485  * @par
 486  * Part of conditional receive process
 487  *
 488  */
 489 static uint16_t eigrp_sequence_encode(struct eigrp *eigrp, struct stream *s)
 490 {
 491         uint16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 492         struct eigrp_interface *ei;
 493         struct listnode *node, *node2, *nnode2;
 494         struct eigrp_neighbor *nbr;
 495         size_t backup_end, size_end;
 496         int found;
 497
 498         // add in the parameters TLV
 499         backup_end = stream_get_endp(s);
 500         stream_putw(s, EIGRP_TLV_SEQ);
 501         size_end = s->endp;
 502         stream_putw(s, 0x0000);
 503         stream_putc(s, IPV4_MAX_BYTELEN);
 504
 505         found = 0;
 506         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 507                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 508                         if (nbr->multicast_queue->count > 0) {
 509                                 length += (uint16_t)stream_put_ipv4(
 510                                         s, nbr->src.s_addr);
 511                                 found = 1;
 512                         }
 513                 }
 514         }
 515
 516         if (found == 0) {
 517                 stream_set_endp(s, backup_end);
 518                 return 0;
 519         }
 520
 521         backup_end = stream_get_endp(s);
 522         stream_set_endp(s, size_end);
 523         stream_putw(s, length);
 524         stream_set_endp(s, backup_end);
 525
 526         return length;
 527 }
 528
 529 /**
 530  * @fn eigrp_sequence_encode
 531  *
 532  * @param[in,out]       s       packet stream TLV is stored to
 533  *
 534  * @return uint16_t    number of bytes added to packet stream
 535  *
 536  * @par
 537  * Part of conditional receive process
 538  *
 539  */
 540 static uint16_t eigrp_next_sequence_encode(struct eigrp *eigrp,
 541                                            struct stream *s)
 542 {
 543         uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 544
 545         // add in the parameters TLV
 546         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 547         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 548         stream_putl(s, eigrp->sequence_number + 1);
 549
 550         return length;
 551 }
 552
 553 /**
 554  * @fn eigrp_hello_parameter_encode
 555  *
 556  * @param[in]           ei      pointer to interface hello packet came in on
 557  * @param[in,out]       s       packet stream TLV is stored to
 558  *
 559  * @return uint16_t     number of bytes added to packet stream
 560  *
 561  * @par
 562  * Encode Parameter TLV, used to convey metric weights and the hold time.
 563  *
 564  * @usage
 565  * Note the addition of K6 for the new extended metrics, and does not apply to
 566  * older TLV packet formats.
 567  */
 568 static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 569                                              struct stream *s, uint8_t flags)
 570 {
 571         // add in the parameters TLV
 572         stream_putw(s, EIGRP_TLV_PARAMETER);
 573         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 574
 575         // if graceful shutdown is needed to be announced, send all 255 in K
 576         // values
 577         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 578                 stream_putc(s, 0xff); /* K1 */
 579                 stream_putc(s, 0xff); /* K2 */
 580                 stream_putc(s, 0xff); /* K3 */
 581                 stream_putc(s, 0xff); /* K4 */
 582                 stream_putc(s, 0xff); /* K5 */
 583                 stream_putc(s, 0xff); /* K6 */
 584         } else                        // set k values
 585         {
 586                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 587                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 588                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 589                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 590                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 591                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 592         }
 593
 594         // and set hold time value..
 595         stream_putw(s, ei->params.v_wait);
 596
 597         return EIGRP_TLV_PARAMETER_LEN;
 598 }
 599
 600 /**
 601  * @fn eigrp_hello_encode
 602  *
 603  * @param[in]           ei      pointer to interface hello packet came in on
 604  * @param[in]           s       packet stream TLV is stored to
 605  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 606  * @param[in]           flags  type of hello packet
 607  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 608  * Termination TLV
 609  *
 610  * @return eigrp_packet         pointer initialize hello packet
 611  *
 612  * @par
 613  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 614  *
 615  */
 616 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 617                                                in_addr_t addr, uint32_t ack,
 618                                                uint8_t flags,
 619                                                struct in_addr *nbr_addr)
 620 {
 621         struct eigrp_packet *ep;
 622         uint16_t length = EIGRP_HEADER_LEN;
 623
 624         // allocate a new packet to be sent
 625         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL);
 626
 627         if (ep) {
 628                 // encode common header feilds
 629                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0,
 630                                          0, ack);
 631
 632                 // encode Authentication TLV
 633                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 634                     && (ei->params.auth_keychain != NULL)) {
 635                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 636                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 637                            && (ei->params.auth_keychain != NULL)) {
 638                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 639                 }
 640
 641                 /* encode appropriate parameters to Hello packet */
 642                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 643                         length += eigrp_hello_parameter_encode(
 644                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 645                 else
 646                         length += eigrp_hello_parameter_encode(
 647                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 648
 649                 // figure out the version of code we're running
 650                 length += eigrp_sw_version_encode(ep->s);
 651
 652                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 653                         length += eigrp_sequence_encode(ei->eigrp, ep->s);
 654                         length += eigrp_next_sequence_encode(ei->eigrp, ep->s);
 655                 }
 656
 657                 // add in the TID list if doing multi-topology
 658                 length += eigrp_tidlist_encode(ep->s);
 659
 660                 /* encode Peer Termination TLV if needed */
 661                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 662                         length +=
 663                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 664
 665                 // Set packet length
 666                 ep->length = length;
 667
 668                 // set soruce address for the hello packet
 669                 ep->dst.s_addr = addr;
 670
 671                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 672                     && (ei->params.auth_keychain != NULL)) {
 673                         eigrp_make_md5_digest(ei, ep->s,
 674                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 675                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 676                            && (ei->params.auth_keychain != NULL)) {
 677                         eigrp_make_sha256_digest(ei, ep->s,
 678                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 679                 }
 680
 681                 // EIGRP Checksum
 682                 eigrp_packet_checksum(ei, ep->s, length);
 683         }
 684
 685         return (ep);
 686 }
 687
 688 /**
 689  * @fn eigrp_hello_send
 690  *
 691  * @param[in]           nbr     neighbor the ACK should be sent to
 692  *
 693  * @return void
 694  *
 695  * @par
 696  *  Send (unicast) a hello packet with the destination address
 697  *  associated with the neighbor.  The eigrp header ACK feild will be
 698  *  updated to the neighbor's sequence number to acknolodge any
 699  *  outstanding packets
 700  */
 701 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 702 {
 703         struct eigrp_packet *ep;
 704
 705         /* if packet succesfully created, add it to the interface queue */
 706         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 707                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 708                                 NULL);
 709
 710         if (ep) {
 711                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 712                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%pI4]",
 713                                    nbr->recv_sequence_number, &nbr->src);
 714
 715                 /* Add packet to the top of the interface output queue*/
 716                 eigrp_fifo_push(nbr->ei->obuf, ep);
 717
 718                 /* Hook thread to write packet. */
 719                 if (nbr->ei->on_write_q == 0) {
 720                         listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 721                         nbr->ei->on_write_q = 1;
 722                 }
 723                 thread_add_write(master, eigrp_write, nbr->ei->eigrp,
 724                                  nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write);
 725         }
 726 }
 727
 728 /**
 729  * @fn eigrp_hello_send
 730  *
 731  * @param[in]           ei      pointer to interface hello should be sent
 732  * @param[in]           flags type of hello packet
 733  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 734  * Termination TLV
 735  *
 736  * @return void
 737  *
 738  * @par
 739  * Build and enqueue a generic (multicast) periodic hello packet for
 740  * sending.  If no packets are currently queues, the packet will be
 741  * sent immadiatly
 742  */
 743 void eigrp_hello_send(struct eigrp_interface *ei, uint8_t flags,
 744                       struct in_addr *nbr_addr)
 745 {
 746         struct eigrp_packet *ep = NULL;
 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(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 }