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 void
  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 void eigrp_hello_timer(struct thread *thread)
  85 {
  86         struct eigrp_interface *ei;
  87
  88         ei = THREAD_ARG(thread);
  89
  90         if (IS_DEBUG_EIGRP(0, TIMERS))
  91                 zlog_debug("Start Hello Timer (%s) Expire [%u]", IF_NAME(ei),
  92                            ei->params.v_hello);
  93
  94         /* Sending hello packet. */
  95         eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL);
  96
  97         /* Hello timer set. */
  98         thread_add_timer(master, eigrp_hello_timer, ei, ei->params.v_hello,
  99                          &ei->t_hello);
 100 }
 101
 102 /**
 103  * @fn eigrp_hello_parameter_decode
 104  *
 105  * @param[in]           nbr     neighbor the ACK should be sent to
 106  * @param[in]           param   pointer packet TLV is stored to
 107  *
 108  * @return uint16_t     number of bytes added to packet stream
 109  *
 110  * @par
 111  * Encode Parameter TLV, used to convey metric weights and the hold time.
 112  *
 113  * @usage
 114  * Note the addition of K6 for the new extended metrics, and does not apply to
 115  * older TLV packet formats.
 116  */
 117 static struct eigrp_neighbor *
 118 eigrp_hello_parameter_decode(struct eigrp_neighbor *nbr,
 119                              struct eigrp_tlv_hdr_type *tlv)
 120 {
 121         struct eigrp *eigrp = nbr->ei->eigrp;
 122         struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv;
 123
 124         /* First validate TLV length */
 125         if (tlv->length < sizeof(struct TLV_Parameter_Type))
 126                 return NULL;
 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                 /* Validate tlv length */
 199                 if (md5->length < sizeof(struct TLV_MD5_Authentication_Type))
 200                         return 0;
 201
 202                 return eigrp_check_md5_digest(s, md5, nbr,
 203                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 204         } else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256) {
 205                 /* Validate tlv length */
 206                 if (md5->length < sizeof(struct TLV_SHA256_Authentication_Type))
 207                         return 0;
 208
 209                 return eigrp_check_sha256_digest(
 210                         s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 211                         nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 212         }
 213
 214         return 0;
 215 }
 216
 217 /**
 218  * @fn eigrp_sw_version_decode
 219  *
 220  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 221  * @param[in]           param   pointer to TLV software version information
 222  *
 223  * @return void
 224  *
 225  * @par
 226  * Read the software version in the specified location.
 227  * This consists of two bytes of OS version, and two bytes of EIGRP
 228  * revision number.
 229  */
 230 static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr,
 231                                     struct eigrp_tlv_hdr_type *tlv)
 232 {
 233         struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 234
 235         /* Validate TLV length */
 236         if (tlv->length < sizeof(struct TLV_Software_Type))
 237                 return;
 238
 239         nbr->os_rel_major = version->vender_major;
 240         nbr->os_rel_minor = version->vender_minor;
 241         nbr->tlv_rel_major = version->eigrp_major;
 242         nbr->tlv_rel_minor = version->eigrp_minor;
 243         return;
 244 }
 245
 246 /**
 247  * @fn eigrp_peer_termination_decode
 248  *
 249  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 250  * @param[in]           tlv     pointer to TLV software version information
 251  *
 252  * @return void
 253  *
 254  * @par
 255  * Read the address in the TLV and match to out address. If
 256  * a match is found, move the sending neighbor to the down state. If
 257  * out address is not in the TLV, then ignore the peer termination
 258  */
 259 static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr,
 260                                           struct eigrp_tlv_hdr_type *tlv)
 261 {
 262         struct eigrp *eigrp = nbr->ei->eigrp;
 263         struct TLV_Peer_Termination_type *param =
 264                 (struct TLV_Peer_Termination_type *)tlv;
 265
 266         /* Validate TLV length */
 267         if (tlv->length < sizeof(struct TLV_Peer_Termination_type))
 268                 return;
 269
 270         uint32_t my_ip = nbr->ei->address.u.prefix4.s_addr;
 271         uint32_t received_ip = param->neighbor_ip;
 272
 273         if (my_ip == received_ip) {
 274                 zlog_info(
 275                         "Neighbor %pI4 (%s) is down: Peer Termination received",
 276                         &nbr->src,
 277                         ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id));
 278                 /* set neighbor to DOWN */
 279                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 280                 /* delete neighbor */
 281                 eigrp_nbr_delete(nbr);
 282         }
 283 }
 284
 285 /**
 286  * @fn eigrp_peer_termination_encode
 287  *
 288  * @param[in,out]   s             packet stream TLV is stored to
 289  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 290  * Termination TLV
 291  *
 292  * @return uint16_t    number of bytes added to packet stream
 293  *
 294  * @par
 295  * Function used to encode Peer Termination TLV to Hello packet.
 296  */
 297 static uint16_t eigrp_peer_termination_encode(struct stream *s,
 298                                               struct in_addr *nbr_addr)
 299 {
 300         uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 301
 302         /* fill in type and length */
 303         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 304         stream_putw(s, length);
 305
 306         /* fill in unknown field 0x04 */
 307         stream_putc(s, 0x04);
 308
 309         /* finally neighbor IP address */
 310         stream_put_ipv4(s, nbr_addr->s_addr);
 311
 312         return (length);
 313 }
 314
 315 /*
 316  * @fn eigrp_hello_receive
 317  *
 318  * @param[in]   eigrp           eigrp routing process
 319  * @param[in]   iph             pointer to ip header
 320  * @param[in]   eigrph          pointer to eigrp header
 321  * @param[in]   s               input ip stream
 322  * @param[in]   ei              eigrp interface packet arrived on
 323  * @param[in]   size            size of eigrp packet
 324  *
 325  * @return void
 326  *
 327  * @par
 328  * This is the main worker function for processing hello packets. It
 329  * will validate the peer associated with the src ip address of the ip
 330  * header, and then decode each of the general TLVs which the packet
 331  * may contain.
 332  *
 333  * @usage
 334  * Not all TLVs are current decoder.  This is a work in progress..
 335  */
 336 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 337                          struct eigrp_header *eigrph, struct stream *s,
 338                          struct eigrp_interface *ei, int size)
 339 {
 340         struct eigrp_tlv_hdr_type *tlv_header;
 341         struct eigrp_neighbor *nbr;
 342         uint16_t type;
 343         uint16_t length;
 344
 345         /* get neighbor struct */
 346         nbr = eigrp_nbr_get(ei, eigrph, iph);
 347
 348         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 349         assert(nbr);
 350
 351         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 352                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%pI4)", size,
 353                            ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id),
 354                            &nbr->src);
 355
 356         size -= EIGRP_HEADER_LEN;
 357         if (size < 0)
 358                 return;
 359
 360         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 361
 362         do {
 363                 type = ntohs(tlv_header->type);
 364                 length = ntohs(tlv_header->length);
 365
 366                 /* Validate length against packet size */
 367                 if (length > size)
 368                         return;
 369
 370                 if ((length > 0) && (length <= size)) {
 371                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 372                                 zlog_debug(
 373                                         "  General TLV(%s)",
 374                                         lookup_msg(eigrp_general_tlv_type_str,
 375                                                    type, NULL));
 376
 377                         // determine what General TLV is being processed
 378                         switch (type) {
 379                         case EIGRP_TLV_PARAMETER:
 380                                 nbr = eigrp_hello_parameter_decode(nbr,
 381                                                                    tlv_header);
 382                                 if (!nbr)
 383                                         return;
 384                                 break;
 385                         case EIGRP_TLV_AUTH: {
 386                                 if (eigrp_hello_authentication_decode(
 387                                             s, tlv_header, nbr)
 388                                     == 0)
 389                                         return;
 390                                 else
 391                                         break;
 392                                 break;
 393                         }
 394                         case EIGRP_TLV_SEQ:
 395                                 break;
 396                         case EIGRP_TLV_SW_VERSION:
 397                                 eigrp_sw_version_decode(nbr, tlv_header);
 398                                 break;
 399                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 400                                 break;
 401                         case EIGRP_TLV_PEER_TERMINATION:
 402                                 eigrp_peer_termination_decode(nbr, tlv_header);
 403                                 return;
 404                                 break;
 405                         case EIGRP_TLV_PEER_MTRLIST:
 406                         case EIGRP_TLV_PEER_TIDLIST:
 407                                 break;
 408                         default:
 409                                 break;
 410                         }
 411                 }
 412
 413                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 414                                                            + length);
 415                 size -= length;
 416
 417         } while (size > 0);
 418
 419
 420         /*If received packet is hello with Parameter TLV*/
 421         if (ntohl(eigrph->ack) == 0) {
 422                 /* increment statistics. */
 423                 ei->hello_in++;
 424                 if (nbr)
 425                         eigrp_nbr_state_update(nbr);
 426         }
 427
 428         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 429                 zlog_debug("Hello Packet received from %pI4", &nbr->src);
 430 }
 431
 432 uint32_t FRR_MAJOR;
 433 uint32_t FRR_MINOR;
 434
 435 void eigrp_sw_version_initialize(void)
 436 {
 437         char ver_string[] = VERSION;
 438         char *dash = strstr(ver_string, "-");
 439         int ret;
 440
 441         if (dash)
 442                 dash[0] = '\0';
 443
 444         ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR,
 445                      &FRR_MINOR);
 446         if (ret != 2)
 447                 flog_err(EC_EIGRP_PACKET,
 448                          "Did not Properly parse %s, please fix VERSION string",
 449                          VERSION);
 450 }
 451
 452 /**
 453  * @fn eigrp_sw_version_encode
 454  *
 455  * @param[in,out]       s       packet stream TLV is stored to
 456  *
 457  * @return uint16_t     number of bytes added to packet stream
 458  *
 459  * @par
 460  * Store the software version in the specified location.
 461  * This consists of two bytes of OS version, and two bytes of EIGRP
 462  * revision number.
 463  */
 464 static uint16_t eigrp_sw_version_encode(struct stream *s)
 465 {
 466         uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 467
 468         // setup the tlv fields
 469         stream_putw(s, EIGRP_TLV_SW_VERSION);
 470         stream_putw(s, length);
 471
 472         stream_putc(s, FRR_MAJOR); //!< major os version
 473         stream_putc(s, FRR_MINOR); //!< minor os version
 474
 475         /* and the core eigrp version */
 476         stream_putc(s, EIGRP_MAJOR_VERSION);
 477         stream_putc(s, EIGRP_MINOR_VERSION);
 478
 479         return (length);
 480 }
 481
 482 /**
 483  * @fn eigrp_tidlist_encode
 484  *
 485  * @param[in,out]       s       packet stream TLV is stored to
 486  *
 487  * @return void
 488  *
 489  * @par
 490  * If doing mutli-topology, then store the supported TID list.
 491  * This is currently a place holder function
 492  */
 493 static uint16_t eigrp_tidlist_encode(struct stream *s)
 494 {
 495         // uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 496         return 0;
 497 }
 498
 499 /**
 500  * @fn eigrp_sequence_encode
 501  *
 502  * @param[in,out]       s       packet stream TLV is stored to
 503  *
 504  * @return uint16_t    number of bytes added to packet stream
 505  *
 506  * @par
 507  * Part of conditional receive process
 508  *
 509  */
 510 static uint16_t eigrp_sequence_encode(struct eigrp *eigrp, struct stream *s)
 511 {
 512         uint16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 513         struct eigrp_interface *ei;
 514         struct listnode *node, *node2, *nnode2;
 515         struct eigrp_neighbor *nbr;
 516         size_t backup_end, size_end;
 517         int found;
 518
 519         // add in the parameters TLV
 520         backup_end = stream_get_endp(s);
 521         stream_putw(s, EIGRP_TLV_SEQ);
 522         size_end = s->endp;
 523         stream_putw(s, 0x0000);
 524         stream_putc(s, IPV4_MAX_BYTELEN);
 525
 526         found = 0;
 527         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 528                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 529                         if (nbr->multicast_queue->count > 0) {
 530                                 length += (uint16_t)stream_put_ipv4(
 531                                         s, nbr->src.s_addr);
 532                                 found = 1;
 533                         }
 534                 }
 535         }
 536
 537         if (found == 0) {
 538                 stream_set_endp(s, backup_end);
 539                 return 0;
 540         }
 541
 542         backup_end = stream_get_endp(s);
 543         stream_set_endp(s, size_end);
 544         stream_putw(s, length);
 545         stream_set_endp(s, backup_end);
 546
 547         return length;
 548 }
 549
 550 /**
 551  * @fn eigrp_sequence_encode
 552  *
 553  * @param[in,out]       s       packet stream TLV is stored to
 554  *
 555  * @return uint16_t    number of bytes added to packet stream
 556  *
 557  * @par
 558  * Part of conditional receive process
 559  *
 560  */
 561 static uint16_t eigrp_next_sequence_encode(struct eigrp *eigrp,
 562                                            struct stream *s)
 563 {
 564         uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 565
 566         // add in the parameters TLV
 567         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 568         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 569         stream_putl(s, eigrp->sequence_number + 1);
 570
 571         return length;
 572 }
 573
 574 /**
 575  * @fn eigrp_hello_parameter_encode
 576  *
 577  * @param[in]           ei      pointer to interface hello packet came in on
 578  * @param[in,out]       s       packet stream TLV is stored to
 579  *
 580  * @return uint16_t     number of bytes added to packet stream
 581  *
 582  * @par
 583  * Encode Parameter TLV, used to convey metric weights and the hold time.
 584  *
 585  * @usage
 586  * Note the addition of K6 for the new extended metrics, and does not apply to
 587  * older TLV packet formats.
 588  */
 589 static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 590                                              struct stream *s, uint8_t flags)
 591 {
 592         // add in the parameters TLV
 593         stream_putw(s, EIGRP_TLV_PARAMETER);
 594         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 595
 596         // if graceful shutdown is needed to be announced, send all 255 in K
 597         // values
 598         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 599                 stream_putc(s, 0xff); /* K1 */
 600                 stream_putc(s, 0xff); /* K2 */
 601                 stream_putc(s, 0xff); /* K3 */
 602                 stream_putc(s, 0xff); /* K4 */
 603                 stream_putc(s, 0xff); /* K5 */
 604                 stream_putc(s, 0xff); /* K6 */
 605         } else                        // set k values
 606         {
 607                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 608                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 609                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 610                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 611                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 612                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 613         }
 614
 615         // and set hold time value..
 616         stream_putw(s, ei->params.v_wait);
 617
 618         return EIGRP_TLV_PARAMETER_LEN;
 619 }
 620
 621 /**
 622  * @fn eigrp_hello_encode
 623  *
 624  * @param[in]           ei      pointer to interface hello packet came in on
 625  * @param[in]           s       packet stream TLV is stored to
 626  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 627  * @param[in]           flags  type of hello packet
 628  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 629  * Termination TLV
 630  *
 631  * @return eigrp_packet         pointer initialize hello packet
 632  *
 633  * @par
 634  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 635  *
 636  */
 637 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 638                                                in_addr_t addr, uint32_t ack,
 639                                                uint8_t flags,
 640                                                struct in_addr *nbr_addr)
 641 {
 642         struct eigrp_packet *ep;
 643         uint16_t length = EIGRP_HEADER_LEN;
 644
 645         // allocate a new packet to be sent
 646         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL);
 647
 648         if (ep) {
 649                 // encode common header feilds
 650                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0,
 651                                          0, ack);
 652
 653                 // encode Authentication TLV
 654                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 655                     && (ei->params.auth_keychain != NULL)) {
 656                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 657                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 658                            && (ei->params.auth_keychain != NULL)) {
 659                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 660                 }
 661
 662                 /* encode appropriate parameters to Hello packet */
 663                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 664                         length += eigrp_hello_parameter_encode(
 665                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 666                 else
 667                         length += eigrp_hello_parameter_encode(
 668                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 669
 670                 // figure out the version of code we're running
 671                 length += eigrp_sw_version_encode(ep->s);
 672
 673                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 674                         length += eigrp_sequence_encode(ei->eigrp, ep->s);
 675                         length += eigrp_next_sequence_encode(ei->eigrp, ep->s);
 676                 }
 677
 678                 // add in the TID list if doing multi-topology
 679                 length += eigrp_tidlist_encode(ep->s);
 680
 681                 /* encode Peer Termination TLV if needed */
 682                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 683                         length +=
 684                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 685
 686                 // Set packet length
 687                 ep->length = length;
 688
 689                 // set soruce address for the hello packet
 690                 ep->dst.s_addr = addr;
 691
 692                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 693                     && (ei->params.auth_keychain != NULL)) {
 694                         eigrp_make_md5_digest(ei, ep->s,
 695                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 696                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 697                            && (ei->params.auth_keychain != NULL)) {
 698                         eigrp_make_sha256_digest(ei, ep->s,
 699                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 700                 }
 701
 702                 // EIGRP Checksum
 703                 eigrp_packet_checksum(ei, ep->s, length);
 704         }
 705
 706         return (ep);
 707 }
 708
 709 /**
 710  * @fn eigrp_hello_send
 711  *
 712  * @param[in]           nbr     neighbor the ACK should be sent to
 713  *
 714  * @return void
 715  *
 716  * @par
 717  *  Send (unicast) a hello packet with the destination address
 718  *  associated with the neighbor.  The eigrp header ACK feild will be
 719  *  updated to the neighbor's sequence number to acknolodge any
 720  *  outstanding packets
 721  */
 722 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 723 {
 724         struct eigrp_packet *ep;
 725
 726         /* if packet succesfully created, add it to the interface queue */
 727         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 728                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 729                                 NULL);
 730
 731         if (ep) {
 732                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 733                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%pI4]",
 734                                    nbr->recv_sequence_number, &nbr->src);
 735
 736                 /* Add packet to the top of the interface output queue*/
 737                 eigrp_fifo_push(nbr->ei->obuf, ep);
 738
 739                 /* Hook thread to write packet. */
 740                 if (nbr->ei->on_write_q == 0) {
 741                         listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 742                         nbr->ei->on_write_q = 1;
 743                 }
 744                 thread_add_write(master, eigrp_write, nbr->ei->eigrp,
 745                                  nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write);
 746         }
 747 }
 748
 749 /**
 750  * @fn eigrp_hello_send
 751  *
 752  * @param[in]           ei      pointer to interface hello should be sent
 753  * @param[in]           flags type of hello packet
 754  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 755  * Termination TLV
 756  *
 757  * @return void
 758  *
 759  * @par
 760  * Build and enqueue a generic (multicast) periodic hello packet for
 761  * sending.  If no packets are currently queues, the packet will be
 762  * sent immadiatly
 763  */
 764 void eigrp_hello_send(struct eigrp_interface *ei, uint8_t flags,
 765                       struct in_addr *nbr_addr)
 766 {
 767         struct eigrp_packet *ep = NULL;
 768
 769         if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 770                 zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 771
 772         /* if packet was succesfully created, then add it to the interface queue
 773          */
 774         ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags,
 775                                 nbr_addr);
 776
 777         if (ep) {
 778                 // Add packet to the top of the interface output queue
 779                 eigrp_fifo_push(ei->obuf, ep);
 780
 781                 /* Hook thread to write packet. */
 782                 if (ei->on_write_q == 0) {
 783                         listnode_add(ei->eigrp->oi_write_q, ei);
 784                         ei->on_write_q = 1;
 785                 }
 786
 787                 if (ei->eigrp->t_write == NULL) {
 788                         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 789                                 thread_execute(master, eigrp_write, ei->eigrp,
 790                                                ei->eigrp->fd);
 791                         } else {
 792                                 thread_add_write(master, eigrp_write, ei->eigrp,
 793                                                  ei->eigrp->fd,
 794                                                  &ei->eigrp->t_write);
 795                         }
 796                 }
 797         }
 798 }