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         /* First validate TLV length */
 129         if (tlv->length < sizeof(struct TLV_Parameter_Type))
 130                 return NULL;
 131
 132         /* copy over the values passed in by the neighbor */
 133         nbr->K1 = param->K1;
 134         nbr->K2 = param->K2;
 135         nbr->K3 = param->K3;
 136         nbr->K4 = param->K4;
 137         nbr->K5 = param->K5;
 138         nbr->K6 = param->K6;
 139         nbr->v_holddown = ntohs(param->hold_time);
 140
 141         /*
 142          * Check K1-K5 have the correct values to be able to become neighbors
 143          * K6 does not have to match
 144          */
 145         if ((eigrp->k_values[0] == nbr->K1) && (eigrp->k_values[1] == nbr->K2)
 146             && (eigrp->k_values[2] == nbr->K3)
 147             && (eigrp->k_values[3] == nbr->K4)
 148             && (eigrp->k_values[4] == nbr->K5)) {
 149
 150                 if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN) {
 151                         zlog_info(
 152                                 "Neighbor %pI4 (%s) is pending: new adjacency",
 153                                 &nbr->src,
 154                                 ifindex2ifname(nbr->ei->ifp->ifindex,
 155                                                eigrp->vrf_id));
 156
 157                         /* Expedited hello sent */
 158                         eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL);
 159
 160                         //     if(ntohl(nbr->ei->address->u.prefix4.s_addr) >
 161                         //     ntohl(nbr->src.s_addr))
 162                         eigrp_update_send_init(nbr);
 163
 164                         eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 165                 }
 166         } else {
 167                 if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN) {
 168                         if ((param->K1 & param->K2 & param->K3 & param->K4
 169                              & param->K5)
 170                             == 255) {
 171                                 zlog_info(
 172                                         "Neighbor %pI4 (%s) is down: Interface PEER-TERMINATION received",
 173                                         &nbr->src,
 174                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 175                                                        eigrp->vrf_id));
 176                                 eigrp_nbr_delete(nbr);
 177                                 return NULL;
 178                         } else {
 179                                 zlog_info(
 180                                         "Neighbor %pI4 (%s) going down: Kvalue mismatch",
 181                                         &nbr->src,
 182                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 183                                                        eigrp->vrf_id));
 184                                 eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 185                         }
 186                 }
 187         }
 188
 189         return nbr;
 190 }
 191
 192 static uint8_t
 193 eigrp_hello_authentication_decode(struct stream *s,
 194                                   struct eigrp_tlv_hdr_type *tlv_header,
 195                                   struct eigrp_neighbor *nbr)
 196 {
 197         struct TLV_MD5_Authentication_Type *md5;
 198
 199         md5 = (struct TLV_MD5_Authentication_Type *)tlv_header;
 200
 201         if (md5->auth_type == EIGRP_AUTH_TYPE_MD5) {
 202                 /* Validate tlv length */
 203                 if (md5->length < sizeof(struct TLV_MD5_Authentication_Type))
 204                         return 0;
 205
 206                 return eigrp_check_md5_digest(s, md5, nbr,
 207                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 208         } else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256) {
 209                 /* Validate tlv length */
 210                 if (md5->length < sizeof(struct TLV_SHA256_Authentication_Type))
 211                         return 0;
 212
 213                 return eigrp_check_sha256_digest(
 214                         s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 215                         nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 216         }
 217
 218         return 0;
 219 }
 220
 221 /**
 222  * @fn eigrp_sw_version_decode
 223  *
 224  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 225  * @param[in]           param   pointer to TLV software version information
 226  *
 227  * @return void
 228  *
 229  * @par
 230  * Read the software version in the specified location.
 231  * This consists of two bytes of OS version, and two bytes of EIGRP
 232  * revision number.
 233  */
 234 static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr,
 235                                     struct eigrp_tlv_hdr_type *tlv)
 236 {
 237         struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 238
 239         /* Validate TLV length */
 240         if (tlv->length < sizeof(struct TLV_Software_Type))
 241                 return;
 242
 243         nbr->os_rel_major = version->vender_major;
 244         nbr->os_rel_minor = version->vender_minor;
 245         nbr->tlv_rel_major = version->eigrp_major;
 246         nbr->tlv_rel_minor = version->eigrp_minor;
 247         return;
 248 }
 249
 250 /**
 251  * @fn eigrp_peer_termination_decode
 252  *
 253  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 254  * @param[in]           tlv     pointer to TLV software version information
 255  *
 256  * @return void
 257  *
 258  * @par
 259  * Read the address in the TLV and match to out address. If
 260  * a match is found, move the sending neighbor to the down state. If
 261  * out address is not in the TLV, then ignore the peer termination
 262  */
 263 static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr,
 264                                           struct eigrp_tlv_hdr_type *tlv)
 265 {
 266         struct eigrp *eigrp = nbr->ei->eigrp;
 267         struct TLV_Peer_Termination_type *param =
 268                 (struct TLV_Peer_Termination_type *)tlv;
 269
 270         /* Validate TLV length */
 271         if (tlv->length < sizeof(struct TLV_Peer_Termination_type))
 272                 return;
 273
 274         uint32_t my_ip = nbr->ei->address.u.prefix4.s_addr;
 275         uint32_t received_ip = param->neighbor_ip;
 276
 277         if (my_ip == received_ip) {
 278                 zlog_info(
 279                         "Neighbor %pI4 (%s) is down: Peer Termination received",
 280                         &nbr->src,
 281                         ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id));
 282                 /* set neighbor to DOWN */
 283                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 284                 /* delete neighbor */
 285                 eigrp_nbr_delete(nbr);
 286         }
 287 }
 288
 289 /**
 290  * @fn eigrp_peer_termination_encode
 291  *
 292  * @param[in,out]   s             packet stream TLV is stored to
 293  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 294  * Termination TLV
 295  *
 296  * @return uint16_t    number of bytes added to packet stream
 297  *
 298  * @par
 299  * Function used to encode Peer Termination TLV to Hello packet.
 300  */
 301 static uint16_t eigrp_peer_termination_encode(struct stream *s,
 302                                               struct in_addr *nbr_addr)
 303 {
 304         uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 305
 306         /* fill in type and length */
 307         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 308         stream_putw(s, length);
 309
 310         /* fill in unknown field 0x04 */
 311         stream_putc(s, 0x04);
 312
 313         /* finally neighbor IP address */
 314         stream_put_ipv4(s, nbr_addr->s_addr);
 315
 316         return (length);
 317 }
 318
 319 /*
 320  * @fn eigrp_hello_receive
 321  *
 322  * @param[in]   eigrp           eigrp routing process
 323  * @param[in]   iph             pointer to ip header
 324  * @param[in]   eigrph          pointer to eigrp header
 325  * @param[in]   s               input ip stream
 326  * @param[in]   ei              eigrp interface packet arrived on
 327  * @param[in]   size            size of eigrp packet
 328  *
 329  * @return void
 330  *
 331  * @par
 332  * This is the main worker function for processing hello packets. It
 333  * will validate the peer associated with the src ip address of the ip
 334  * header, and then decode each of the general TLVs which the packet
 335  * may contain.
 336  *
 337  * @usage
 338  * Not all TLVs are current decoder.  This is a work in progress..
 339  */
 340 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 341                          struct eigrp_header *eigrph, struct stream *s,
 342                          struct eigrp_interface *ei, int size)
 343 {
 344         struct eigrp_tlv_hdr_type *tlv_header;
 345         struct eigrp_neighbor *nbr;
 346         uint16_t type;
 347         uint16_t length;
 348
 349         /* get neighbor struct */
 350         nbr = eigrp_nbr_get(ei, eigrph, iph);
 351
 352         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 353         assert(nbr);
 354
 355         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 356                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%pI4)", size,
 357                            ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id),
 358                            &nbr->src);
 359
 360         size -= EIGRP_HEADER_LEN;
 361         if (size < 0)
 362                 return;
 363
 364         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 365
 366         do {
 367                 type = ntohs(tlv_header->type);
 368                 length = ntohs(tlv_header->length);
 369
 370                 /* Validate length against packet size */
 371                 if (length > size)
 372                         return;
 373
 374                 if ((length > 0) && (length <= size)) {
 375                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 376                                 zlog_debug(
 377                                         "  General TLV(%s)",
 378                                         lookup_msg(eigrp_general_tlv_type_str,
 379                                                    type, NULL));
 380
 381                         // determine what General TLV is being processed
 382                         switch (type) {
 383                         case EIGRP_TLV_PARAMETER:
 384                                 nbr = eigrp_hello_parameter_decode(nbr,
 385                                                                    tlv_header);
 386                                 if (!nbr)
 387                                         return;
 388                                 break;
 389                         case EIGRP_TLV_AUTH: {
 390                                 if (eigrp_hello_authentication_decode(
 391                                             s, tlv_header, nbr)
 392                                     == 0)
 393                                         return;
 394                                 else
 395                                         break;
 396                                 break;
 397                         }
 398                         case EIGRP_TLV_SEQ:
 399                                 break;
 400                         case EIGRP_TLV_SW_VERSION:
 401                                 eigrp_sw_version_decode(nbr, tlv_header);
 402                                 break;
 403                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 404                                 break;
 405                         case EIGRP_TLV_PEER_TERMINATION:
 406                                 eigrp_peer_termination_decode(nbr, tlv_header);
 407                                 return;
 408                                 break;
 409                         case EIGRP_TLV_PEER_MTRLIST:
 410                         case EIGRP_TLV_PEER_TIDLIST:
 411                                 break;
 412                         default:
 413                                 break;
 414                         }
 415                 }
 416
 417                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 418                                                            + length);
 419                 size -= length;
 420
 421         } while (size > 0);
 422
 423
 424         /*If received packet is hello with Parameter TLV*/
 425         if (ntohl(eigrph->ack) == 0) {
 426                 /* increment statistics. */
 427                 ei->hello_in++;
 428                 if (nbr)
 429                         eigrp_nbr_state_update(nbr);
 430         }
 431
 432         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 433                 zlog_debug("Hello Packet received from %pI4", &nbr->src);
 434 }
 435
 436 uint32_t FRR_MAJOR;
 437 uint32_t FRR_MINOR;
 438
 439 void eigrp_sw_version_initialize(void)
 440 {
 441         char ver_string[] = VERSION;
 442         char *dash = strstr(ver_string, "-");
 443         int ret;
 444
 445         if (dash)
 446                 dash[0] = '\0';
 447
 448         ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR,
 449                      &FRR_MINOR);
 450         if (ret != 2)
 451                 flog_err(EC_EIGRP_PACKET,
 452                          "Did not Properly parse %s, please fix VERSION string",
 453                          VERSION);
 454 }
 455
 456 /**
 457  * @fn eigrp_sw_version_encode
 458  *
 459  * @param[in,out]       s       packet stream TLV is stored to
 460  *
 461  * @return uint16_t     number of bytes added to packet stream
 462  *
 463  * @par
 464  * Store the software version in the specified location.
 465  * This consists of two bytes of OS version, and two bytes of EIGRP
 466  * revision number.
 467  */
 468 static uint16_t eigrp_sw_version_encode(struct stream *s)
 469 {
 470         uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 471
 472         // setup the tlv fields
 473         stream_putw(s, EIGRP_TLV_SW_VERSION);
 474         stream_putw(s, length);
 475
 476         stream_putc(s, FRR_MAJOR); //!< major os version
 477         stream_putc(s, FRR_MINOR); //!< minor os version
 478
 479         /* and the core eigrp version */
 480         stream_putc(s, EIGRP_MAJOR_VERSION);
 481         stream_putc(s, EIGRP_MINOR_VERSION);
 482
 483         return (length);
 484 }
 485
 486 /**
 487  * @fn eigrp_tidlist_encode
 488  *
 489  * @param[in,out]       s       packet stream TLV is stored to
 490  *
 491  * @return void
 492  *
 493  * @par
 494  * If doing mutli-topology, then store the supported TID list.
 495  * This is currently a place holder function
 496  */
 497 static uint16_t eigrp_tidlist_encode(struct stream *s)
 498 {
 499         // uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 500         return 0;
 501 }
 502
 503 /**
 504  * @fn eigrp_sequence_encode
 505  *
 506  * @param[in,out]       s       packet stream TLV is stored to
 507  *
 508  * @return uint16_t    number of bytes added to packet stream
 509  *
 510  * @par
 511  * Part of conditional receive process
 512  *
 513  */
 514 static uint16_t eigrp_sequence_encode(struct eigrp *eigrp, struct stream *s)
 515 {
 516         uint16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 517         struct eigrp_interface *ei;
 518         struct listnode *node, *node2, *nnode2;
 519         struct eigrp_neighbor *nbr;
 520         size_t backup_end, size_end;
 521         int found;
 522
 523         // add in the parameters TLV
 524         backup_end = stream_get_endp(s);
 525         stream_putw(s, EIGRP_TLV_SEQ);
 526         size_end = s->endp;
 527         stream_putw(s, 0x0000);
 528         stream_putc(s, IPV4_MAX_BYTELEN);
 529
 530         found = 0;
 531         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 532                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 533                         if (nbr->multicast_queue->count > 0) {
 534                                 length += (uint16_t)stream_put_ipv4(
 535                                         s, nbr->src.s_addr);
 536                                 found = 1;
 537                         }
 538                 }
 539         }
 540
 541         if (found == 0) {
 542                 stream_set_endp(s, backup_end);
 543                 return 0;
 544         }
 545
 546         backup_end = stream_get_endp(s);
 547         stream_set_endp(s, size_end);
 548         stream_putw(s, length);
 549         stream_set_endp(s, backup_end);
 550
 551         return length;
 552 }
 553
 554 /**
 555  * @fn eigrp_sequence_encode
 556  *
 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  * Part of conditional receive process
 563  *
 564  */
 565 static uint16_t eigrp_next_sequence_encode(struct eigrp *eigrp,
 566                                            struct stream *s)
 567 {
 568         uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 569
 570         // add in the parameters TLV
 571         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 572         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 573         stream_putl(s, eigrp->sequence_number + 1);
 574
 575         return length;
 576 }
 577
 578 /**
 579  * @fn eigrp_hello_parameter_encode
 580  *
 581  * @param[in]           ei      pointer to interface hello packet came in on
 582  * @param[in,out]       s       packet stream TLV is stored to
 583  *
 584  * @return uint16_t     number of bytes added to packet stream
 585  *
 586  * @par
 587  * Encode Parameter TLV, used to convey metric weights and the hold time.
 588  *
 589  * @usage
 590  * Note the addition of K6 for the new extended metrics, and does not apply to
 591  * older TLV packet formats.
 592  */
 593 static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 594                                              struct stream *s, uint8_t flags)
 595 {
 596         // add in the parameters TLV
 597         stream_putw(s, EIGRP_TLV_PARAMETER);
 598         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 599
 600         // if graceful shutdown is needed to be announced, send all 255 in K
 601         // values
 602         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 603                 stream_putc(s, 0xff); /* K1 */
 604                 stream_putc(s, 0xff); /* K2 */
 605                 stream_putc(s, 0xff); /* K3 */
 606                 stream_putc(s, 0xff); /* K4 */
 607                 stream_putc(s, 0xff); /* K5 */
 608                 stream_putc(s, 0xff); /* K6 */
 609         } else                        // set k values
 610         {
 611                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 612                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 613                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 614                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 615                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 616                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 617         }
 618
 619         // and set hold time value..
 620         stream_putw(s, ei->params.v_wait);
 621
 622         return EIGRP_TLV_PARAMETER_LEN;
 623 }
 624
 625 /**
 626  * @fn eigrp_hello_encode
 627  *
 628  * @param[in]           ei      pointer to interface hello packet came in on
 629  * @param[in]           s       packet stream TLV is stored to
 630  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 631  * @param[in]           flags  type of hello packet
 632  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 633  * Termination TLV
 634  *
 635  * @return eigrp_packet         pointer initialize hello packet
 636  *
 637  * @par
 638  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 639  *
 640  */
 641 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 642                                                in_addr_t addr, uint32_t ack,
 643                                                uint8_t flags,
 644                                                struct in_addr *nbr_addr)
 645 {
 646         struct eigrp_packet *ep;
 647         uint16_t length = EIGRP_HEADER_LEN;
 648
 649         // allocate a new packet to be sent
 650         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL);
 651
 652         if (ep) {
 653                 // encode common header feilds
 654                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0,
 655                                          0, ack);
 656
 657                 // encode Authentication TLV
 658                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 659                     && (ei->params.auth_keychain != NULL)) {
 660                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 661                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 662                            && (ei->params.auth_keychain != NULL)) {
 663                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 664                 }
 665
 666                 /* encode appropriate parameters to Hello packet */
 667                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 668                         length += eigrp_hello_parameter_encode(
 669                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 670                 else
 671                         length += eigrp_hello_parameter_encode(
 672                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 673
 674                 // figure out the version of code we're running
 675                 length += eigrp_sw_version_encode(ep->s);
 676
 677                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 678                         length += eigrp_sequence_encode(ei->eigrp, ep->s);
 679                         length += eigrp_next_sequence_encode(ei->eigrp, ep->s);
 680                 }
 681
 682                 // add in the TID list if doing multi-topology
 683                 length += eigrp_tidlist_encode(ep->s);
 684
 685                 /* encode Peer Termination TLV if needed */
 686                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 687                         length +=
 688                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 689
 690                 // Set packet length
 691                 ep->length = length;
 692
 693                 // set soruce address for the hello packet
 694                 ep->dst.s_addr = addr;
 695
 696                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 697                     && (ei->params.auth_keychain != NULL)) {
 698                         eigrp_make_md5_digest(ei, ep->s,
 699                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 700                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 701                            && (ei->params.auth_keychain != NULL)) {
 702                         eigrp_make_sha256_digest(ei, ep->s,
 703                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 704                 }
 705
 706                 // EIGRP Checksum
 707                 eigrp_packet_checksum(ei, ep->s, length);
 708         }
 709
 710         return (ep);
 711 }
 712
 713 /**
 714  * @fn eigrp_hello_send
 715  *
 716  * @param[in]           nbr     neighbor the ACK should be sent to
 717  *
 718  * @return void
 719  *
 720  * @par
 721  *  Send (unicast) a hello packet with the destination address
 722  *  associated with the neighbor.  The eigrp header ACK feild will be
 723  *  updated to the neighbor's sequence number to acknolodge any
 724  *  outstanding packets
 725  */
 726 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 727 {
 728         struct eigrp_packet *ep;
 729
 730         /* if packet succesfully created, add it to the interface queue */
 731         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 732                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 733                                 NULL);
 734
 735         if (ep) {
 736                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 737                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%pI4]",
 738                                    nbr->recv_sequence_number, &nbr->src);
 739
 740                 /* Add packet to the top of the interface output queue*/
 741                 eigrp_fifo_push(nbr->ei->obuf, ep);
 742
 743                 /* Hook thread to write packet. */
 744                 if (nbr->ei->on_write_q == 0) {
 745                         listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 746                         nbr->ei->on_write_q = 1;
 747                 }
 748                 thread_add_write(master, eigrp_write, nbr->ei->eigrp,
 749                                  nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write);
 750         }
 751 }
 752
 753 /**
 754  * @fn eigrp_hello_send
 755  *
 756  * @param[in]           ei      pointer to interface hello should be sent
 757  * @param[in]           flags type of hello packet
 758  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 759  * Termination TLV
 760  *
 761  * @return void
 762  *
 763  * @par
 764  * Build and enqueue a generic (multicast) periodic hello packet for
 765  * sending.  If no packets are currently queues, the packet will be
 766  * sent immadiatly
 767  */
 768 void eigrp_hello_send(struct eigrp_interface *ei, uint8_t flags,
 769                       struct in_addr *nbr_addr)
 770 {
 771         struct eigrp_packet *ep = NULL;
 772
 773         if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 774                 zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 775
 776         /* if packet was succesfully created, then add it to the interface queue
 777          */
 778         ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags,
 779                                 nbr_addr);
 780
 781         if (ep) {
 782                 // Add packet to the top of the interface output queue
 783                 eigrp_fifo_push(ei->obuf, ep);
 784
 785                 /* Hook thread to write packet. */
 786                 if (ei->on_write_q == 0) {
 787                         listnode_add(ei->eigrp->oi_write_q, ei);
 788                         ei->on_write_q = 1;
 789                 }
 790
 791                 if (ei->eigrp->t_write == NULL) {
 792                         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 793                                 thread_execute(master, eigrp_write, ei->eigrp,
 794                                                ei->eigrp->fd);
 795                         } else {
 796                                 thread_add_write(master, eigrp_write, ei->eigrp,
 797                                                  ei->eigrp->fd,
 798                                                  &ei->eigrp->t_write);
 799                         }
 800                 }
 801         }
 802 }