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                                                  eigrp->vrf_id));
 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                                                        eigrp->vrf_id));
 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                                                        eigrp->vrf_id));
 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 eigrp *eigrp = nbr->ei->eigrp;
 249         struct TLV_Peer_Termination_type *param =
 250                 (struct TLV_Peer_Termination_type *)tlv;
 251
 252         uint32_t my_ip = nbr->ei->address.u.prefix4.s_addr;
 253         uint32_t received_ip = param->neighbor_ip;
 254
 255         if (my_ip == received_ip) {
 256                 zlog_info("Neighbor %s (%s) is down: Peer Termination received",
 257                           inet_ntoa(nbr->src),
 258                           ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id));
 259                 /* set neighbor to DOWN */
 260                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 261                 /* delete neighbor */
 262                 eigrp_nbr_delete(nbr);
 263         }
 264 }
 265
 266 /**
 267  * @fn eigrp_peer_termination_encode
 268  *
 269  * @param[in,out]   s             packet stream TLV is stored to
 270  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 271  * Termination TLV
 272  *
 273  * @return uint16_t    number of bytes added to packet stream
 274  *
 275  * @par
 276  * Function used to encode Peer Termination TLV to Hello packet.
 277  */
 278 static uint16_t eigrp_peer_termination_encode(struct stream *s,
 279                                               struct in_addr *nbr_addr)
 280 {
 281         uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 282
 283         /* fill in type and length */
 284         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 285         stream_putw(s, length);
 286
 287         /* fill in unknown field 0x04 */
 288         stream_putc(s, 0x04);
 289
 290         /* finally neighbor IP address */
 291         stream_put_ipv4(s, nbr_addr->s_addr);
 292
 293         return (length);
 294 }
 295
 296 /*
 297  * @fn eigrp_hello_receive
 298  *
 299  * @param[in]   eigrp           eigrp routing process
 300  * @param[in]   iph             pointer to ip header
 301  * @param[in]   eigrph          pointer to eigrp header
 302  * @param[in]   s               input ip stream
 303  * @param[in]   ei              eigrp interface packet arrived on
 304  * @param[in]   size            size of eigrp packet
 305  *
 306  * @return void
 307  *
 308  * @par
 309  * This is the main worker function for processing hello packets. It
 310  * will validate the peer associated with the src ip address of the ip
 311  * header, and then decode each of the general TLVs which the packet
 312  * may contain.
 313  *
 314  * @usage
 315  * Not all TLVs are current decoder.  This is a work in progress..
 316  */
 317 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 318                          struct eigrp_header *eigrph, struct stream *s,
 319                          struct eigrp_interface *ei, int size)
 320 {
 321         struct eigrp_tlv_hdr_type *tlv_header;
 322         struct eigrp_neighbor *nbr;
 323         uint16_t type;
 324         uint16_t length;
 325
 326         /* get neighbor struct */
 327         nbr = eigrp_nbr_get(ei, eigrph, iph);
 328
 329         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 330         assert(nbr);
 331
 332         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 333                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%s)", size,
 334                            ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id),
 335                            inet_ntoa(nbr->src));
 336
 337         size -= EIGRP_HEADER_LEN;
 338         if (size < 0)
 339                 return;
 340
 341         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 342
 343         do {
 344                 type = ntohs(tlv_header->type);
 345                 length = ntohs(tlv_header->length);
 346
 347                 if ((length > 0) && (length <= size)) {
 348                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 349                                 zlog_debug(
 350                                         "  General TLV(%s)",
 351                                         lookup_msg(eigrp_general_tlv_type_str,
 352                                                    type, NULL));
 353
 354                         // determine what General TLV is being processed
 355                         switch (type) {
 356                         case EIGRP_TLV_PARAMETER:
 357                                 nbr = eigrp_hello_parameter_decode(nbr,
 358                                                                    tlv_header);
 359                                 if (!nbr)
 360                                         return;
 361                                 break;
 362                         case EIGRP_TLV_AUTH: {
 363                                 if (eigrp_hello_authentication_decode(
 364                                             s, tlv_header, nbr)
 365                                     == 0)
 366                                         return;
 367                                 else
 368                                         break;
 369                                 break;
 370                         }
 371                         case EIGRP_TLV_SEQ:
 372                                 break;
 373                         case EIGRP_TLV_SW_VERSION:
 374                                 eigrp_sw_version_decode(nbr, tlv_header);
 375                                 break;
 376                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 377                                 break;
 378                         case EIGRP_TLV_PEER_TERMINATION:
 379                                 eigrp_peer_termination_decode(nbr, tlv_header);
 380                                 return;
 381                                 break;
 382                         case EIGRP_TLV_PEER_MTRLIST:
 383                         case EIGRP_TLV_PEER_TIDLIST:
 384                                 break;
 385                         default:
 386                                 break;
 387                         }
 388                 }
 389
 390                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 391                                                            + length);
 392                 size -= length;
 393
 394         } while (size > 0);
 395
 396
 397         /*If received packet is hello with Parameter TLV*/
 398         if (ntohl(eigrph->ack) == 0) {
 399                 /* increment statistics. */
 400                 ei->hello_in++;
 401                 if (nbr)
 402                         eigrp_nbr_state_update(nbr);
 403         }
 404
 405         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 406                 zlog_debug("Hello Packet received from %s",
 407                            inet_ntoa(nbr->src));
 408 }
 409
 410 uint32_t FRR_MAJOR;
 411 uint32_t FRR_MINOR;
 412
 413 void eigrp_sw_version_initialize(void)
 414 {
 415         char ver_string[] = VERSION;
 416         char *dash = strstr(ver_string, "-");
 417         int ret;
 418
 419         if (dash)
 420                 dash[0] = '\0';
 421
 422         ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR,
 423                      &FRR_MINOR);
 424         if (ret != 2)
 425                 flog_err(EC_EIGRP_PACKET,
 426                          "Did not Properly parse %s, please fix VERSION string",
 427                          VERSION);
 428 }
 429
 430 /**
 431  * @fn eigrp_sw_version_encode
 432  *
 433  * @param[in,out]       s       packet stream TLV is stored to
 434  *
 435  * @return uint16_t     number of bytes added to packet stream
 436  *
 437  * @par
 438  * Store the software version in the specified location.
 439  * This consists of two bytes of OS version, and two bytes of EIGRP
 440  * revision number.
 441  */
 442 static uint16_t eigrp_sw_version_encode(struct stream *s)
 443 {
 444         uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 445
 446         // setup the tlv fields
 447         stream_putw(s, EIGRP_TLV_SW_VERSION);
 448         stream_putw(s, length);
 449
 450         stream_putc(s, FRR_MAJOR); //!< major os version
 451         stream_putc(s, FRR_MINOR); //!< minor os version
 452
 453         /* and the core eigrp version */
 454         stream_putc(s, EIGRP_MAJOR_VERSION);
 455         stream_putc(s, EIGRP_MINOR_VERSION);
 456
 457         return (length);
 458 }
 459
 460 /**
 461  * @fn eigrp_tidlist_encode
 462  *
 463  * @param[in,out]       s       packet stream TLV is stored to
 464  *
 465  * @return void
 466  *
 467  * @par
 468  * If doing mutli-topology, then store the supported TID list.
 469  * This is currently a place holder function
 470  */
 471 static uint16_t eigrp_tidlist_encode(struct stream *s)
 472 {
 473         // uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 474         return 0;
 475 }
 476
 477 /**
 478  * @fn eigrp_sequence_encode
 479  *
 480  * @param[in,out]       s       packet stream TLV is stored to
 481  *
 482  * @return uint16_t    number of bytes added to packet stream
 483  *
 484  * @par
 485  * Part of conditional receive process
 486  *
 487  */
 488 static uint16_t eigrp_sequence_encode(struct eigrp *eigrp, struct stream *s)
 489 {
 490         uint16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 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         // add in the parameters TLV
 498         backup_end = stream_get_endp(s);
 499         stream_putw(s, EIGRP_TLV_SEQ);
 500         size_end = s->endp;
 501         stream_putw(s, 0x0000);
 502         stream_putc(s, IPV4_MAX_BYTELEN);
 503
 504         found = 0;
 505         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 506                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 507                         if (nbr->multicast_queue->count > 0) {
 508                                 length += (uint16_t)stream_put_ipv4(
 509                                         s, nbr->src.s_addr);
 510                                 found = 1;
 511                         }
 512                 }
 513         }
 514
 515         if (found == 0) {
 516                 stream_set_endp(s, backup_end);
 517                 return 0;
 518         }
 519
 520         backup_end = stream_get_endp(s);
 521         stream_set_endp(s, size_end);
 522         stream_putw(s, length);
 523         stream_set_endp(s, backup_end);
 524
 525         return length;
 526 }
 527
 528 /**
 529  * @fn eigrp_sequence_encode
 530  *
 531  * @param[in,out]       s       packet stream TLV is stored to
 532  *
 533  * @return uint16_t    number of bytes added to packet stream
 534  *
 535  * @par
 536  * Part of conditional receive process
 537  *
 538  */
 539 static uint16_t eigrp_next_sequence_encode(struct eigrp *eigrp,
 540                                            struct stream *s)
 541 {
 542         uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 543
 544         // add in the parameters TLV
 545         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 546         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 547         stream_putl(s, eigrp->sequence_number + 1);
 548
 549         return length;
 550 }
 551
 552 /**
 553  * @fn eigrp_hello_parameter_encode
 554  *
 555  * @param[in]           ei      pointer to interface hello packet came in on
 556  * @param[in,out]       s       packet stream TLV is stored to
 557  *
 558  * @return uint16_t     number of bytes added to packet stream
 559  *
 560  * @par
 561  * Encode Parameter TLV, used to convey metric weights and the hold time.
 562  *
 563  * @usage
 564  * Note the addition of K6 for the new extended metrics, and does not apply to
 565  * older TLV packet formats.
 566  */
 567 static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 568                                              struct stream *s, uint8_t flags)
 569 {
 570         // add in the parameters TLV
 571         stream_putw(s, EIGRP_TLV_PARAMETER);
 572         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 573
 574         // if graceful shutdown is needed to be announced, send all 255 in K
 575         // values
 576         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 577                 stream_putc(s, 0xff); /* K1 */
 578                 stream_putc(s, 0xff); /* K2 */
 579                 stream_putc(s, 0xff); /* K3 */
 580                 stream_putc(s, 0xff); /* K4 */
 581                 stream_putc(s, 0xff); /* K5 */
 582                 stream_putc(s, 0xff); /* K6 */
 583         } else                        // set k values
 584         {
 585                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 586                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 587                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 588                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 589                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 590                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 591         }
 592
 593         // and set hold time value..
 594         stream_putw(s, ei->params.v_wait);
 595
 596         return EIGRP_TLV_PARAMETER_LEN;
 597 }
 598
 599 /**
 600  * @fn eigrp_hello_encode
 601  *
 602  * @param[in]           ei      pointer to interface hello packet came in on
 603  * @param[in]           s       packet stream TLV is stored to
 604  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 605  * @param[in]           flags  type of hello packet
 606  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 607  * Termination TLV
 608  *
 609  * @return eigrp_packet         pointer initialize hello packet
 610  *
 611  * @par
 612  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 613  *
 614  */
 615 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 616                                                in_addr_t addr, uint32_t ack,
 617                                                uint8_t flags,
 618                                                struct in_addr *nbr_addr)
 619 {
 620         struct eigrp_packet *ep;
 621         uint16_t length = EIGRP_HEADER_LEN;
 622
 623         // allocate a new packet to be sent
 624         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL);
 625
 626         if (ep) {
 627                 // encode common header feilds
 628                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0,
 629                                          0, ack);
 630
 631                 // encode Authentication TLV
 632                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 633                     && (ei->params.auth_keychain != NULL)) {
 634                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 635                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 636                            && (ei->params.auth_keychain != NULL)) {
 637                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 638                 }
 639
 640                 /* encode appropriate parameters to Hello packet */
 641                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 642                         length += eigrp_hello_parameter_encode(
 643                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 644                 else
 645                         length += eigrp_hello_parameter_encode(
 646                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 647
 648                 // figure out the version of code we're running
 649                 length += eigrp_sw_version_encode(ep->s);
 650
 651                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 652                         length += eigrp_sequence_encode(ei->eigrp, ep->s);
 653                         length += eigrp_next_sequence_encode(ei->eigrp, ep->s);
 654                 }
 655
 656                 // add in the TID list if doing multi-topology
 657                 length += eigrp_tidlist_encode(ep->s);
 658
 659                 /* encode Peer Termination TLV if needed */
 660                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 661                         length +=
 662                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 663
 664                 // Set packet length
 665                 ep->length = length;
 666
 667                 // set soruce address for the hello packet
 668                 ep->dst.s_addr = addr;
 669
 670                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 671                     && (ei->params.auth_keychain != NULL)) {
 672                         eigrp_make_md5_digest(ei, ep->s,
 673                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 674                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 675                            && (ei->params.auth_keychain != NULL)) {
 676                         eigrp_make_sha256_digest(ei, ep->s,
 677                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 678                 }
 679
 680                 // EIGRP Checksum
 681                 eigrp_packet_checksum(ei, ep->s, length);
 682         }
 683
 684         return (ep);
 685 }
 686
 687 /**
 688  * @fn eigrp_hello_send
 689  *
 690  * @param[in]           nbr     neighbor the ACK should be sent to
 691  *
 692  * @return void
 693  *
 694  * @par
 695  *  Send (unicast) a hello packet with the destination address
 696  *  associated with the neighbor.  The eigrp header ACK feild will be
 697  *  updated to the neighbor's sequence number to acknolodge any
 698  *  outstanding packets
 699  */
 700 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 701 {
 702         struct eigrp_packet *ep;
 703
 704         /* if packet succesfully created, add it to the interface queue */
 705         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 706                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 707                                 NULL);
 708
 709         if (ep) {
 710                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 711                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%s]",
 712                                    nbr->recv_sequence_number,
 713                                    inet_ntoa(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 this is passive interface, do not send EIGRP Hello.
 749            if ((EIGRP_IF_PASSIVE_STATUS (ei) == EIGRP_IF_PASSIVE) ||
 750            (ei->type != EIGRP_IFTYPE_NBMA))
 751            return;
 752         */
 753
 754         if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 755                 zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 756
 757         /* if packet was succesfully created, then add it to the interface queue
 758          */
 759         ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags,
 760                                 nbr_addr);
 761
 762         if (ep) {
 763                 // Add packet to the top of the interface output queue
 764                 eigrp_fifo_push(ei->obuf, ep);
 765
 766                 /* Hook thread to write packet. */
 767                 if (ei->on_write_q == 0) {
 768                         listnode_add(ei->eigrp->oi_write_q, ei);
 769                         ei->on_write_q = 1;
 770                 }
 771
 772                 if (ei->eigrp->t_write == NULL) {
 773                         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 774                                 thread_execute(master, eigrp_write, ei->eigrp,
 775                                                ei->eigrp->fd);
 776                         } else {
 777                                 thread_add_write(master, eigrp_write, ei->eigrp,
 778                                                  ei->eigrp->fd,
 779                                                  &ei->eigrp->t_write);
 780                         }
 781                 }
 782         }
 783 }