nhrpd/nhrp_peer.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* NHRP peer functions
   3  * Copyright (c) 2014-2015 Timo Teräs
   4  */
   5
   6 #ifdef HAVE_CONFIG_H
   7 #include "config.h"
   8 #endif
   9
  10 #include <netinet/if_ether.h>
  11
  12 #include "zebra.h"
  13 #include "memory.h"
  14 #include "frrevent.h"
  15 #include "hash.h"
  16 #include "network.h"
  17
  18 #include "nhrpd.h"
  19 #include "nhrp_protocol.h"
  20 #include "os.h"
  21
  22 DEFINE_MTYPE_STATIC(NHRPD, NHRP_PEER, "NHRP peer entry");
  23
  24 struct ipv6hdr {
  25         uint8_t priority_version;
  26         uint8_t flow_lbl[3];
  27         uint16_t payload_len;
  28         uint8_t nexthdr;
  29         uint8_t hop_limit;
  30         struct in6_addr saddr;
  31         struct in6_addr daddr;
  32 };
  33
  34 static void nhrp_packet_debug(struct zbuf *zb, const char *dir);
  35
  36 static void nhrp_peer_check_delete(struct nhrp_peer *p)
  37 {
  38         struct nhrp_interface *nifp = p->ifp->info;
  39
  40         if (p->ref || notifier_active(&p->notifier_list))
  41                 return;
  42
  43         debugf(NHRP_DEBUG_COMMON, "Deleting peer ref:%d remote:%pSU local:%pSU",
  44                p->ref, &p->vc->remote.nbma, &p->vc->local.nbma);
  45
  46         EVENT_OFF(p->t_fallback);
  47         EVENT_OFF(p->t_timer);
  48         hash_release(nifp->peer_hash, p);
  49         nhrp_interface_notify_del(p->ifp, &p->ifp_notifier);
  50         nhrp_vc_notify_del(p->vc, &p->vc_notifier);
  51         XFREE(MTYPE_NHRP_PEER, p);
  52 }
  53
  54 static void nhrp_peer_notify_up(struct event *t)
  55 {
  56         struct nhrp_peer *p = EVENT_ARG(t);
  57         struct nhrp_vc *vc = p->vc;
  58         struct interface *ifp = p->ifp;
  59         struct nhrp_interface *nifp = ifp->info;
  60
  61         p->t_fallback = NULL;
  62         if (nifp->enabled && (!nifp->ipsec_profile || vc->ipsec)) {
  63                 p->online = 1;
  64                 nhrp_peer_ref(p);
  65                 notifier_call(&p->notifier_list, NOTIFY_PEER_UP);
  66                 nhrp_peer_unref(p);
  67         }
  68 }
  69
  70 static void __nhrp_peer_check(struct nhrp_peer *p)
  71 {
  72         struct nhrp_vc *vc = p->vc;
  73         struct interface *ifp = p->ifp;
  74         struct nhrp_interface *nifp = ifp->info;
  75         unsigned online;
  76
  77         online = nifp->enabled && (!nifp->ipsec_profile || vc->ipsec);
  78         if (p->online != online) {
  79                 EVENT_OFF(p->t_fallback);
  80                 if (online && notifier_active(&p->notifier_list)) {
  81                         /* If we requested the IPsec connection, delay
  82                          * the up notification a bit to allow things
  83                          * settle down. This allows IKE to install
  84                          * SPDs and SAs. */
  85                         event_add_timer_msec(master, nhrp_peer_notify_up, p, 50,
  86                                              &p->t_fallback);
  87                 } else {
  88                         nhrp_peer_ref(p);
  89                         p->online = online;
  90                         if (online) {
  91                                 notifier_call(&p->notifier_list,
  92                                               NOTIFY_PEER_UP);
  93                         } else {
  94                                 p->requested = p->fallback_requested = 0;
  95                                 notifier_call(&p->notifier_list,
  96                                               NOTIFY_PEER_DOWN);
  97                         }
  98                         nhrp_peer_unref(p);
  99                 }
 100         }
 101 }
 102
 103 static void nhrp_peer_vc_notify(struct notifier_block *n, unsigned long cmd)
 104 {
 105         struct nhrp_peer *p = container_of(n, struct nhrp_peer, vc_notifier);
 106
 107         switch (cmd) {
 108         case NOTIFY_VC_IPSEC_CHANGED:
 109                 __nhrp_peer_check(p);
 110                 break;
 111         case NOTIFY_VC_IPSEC_UPDATE_NBMA:
 112                 nhrp_peer_ref(p);
 113                 notifier_call(&p->notifier_list, NOTIFY_PEER_NBMA_CHANGING);
 114                 nhrp_peer_unref(p);
 115                 break;
 116         }
 117 }
 118
 119 static void nhrp_peer_ifp_notify(struct notifier_block *n, unsigned long cmd)
 120 {
 121         struct nhrp_peer *p = container_of(n, struct nhrp_peer, ifp_notifier);
 122         struct nhrp_interface *nifp;
 123         struct nhrp_vc *vc;
 124
 125         nhrp_peer_ref(p);
 126         switch (cmd) {
 127         case NOTIFY_INTERFACE_UP:
 128         case NOTIFY_INTERFACE_DOWN:
 129                 __nhrp_peer_check(p);
 130                 break;
 131         case NOTIFY_INTERFACE_NBMA_CHANGED:
 132                 /* Source NBMA changed, rebind to new VC */
 133                 nifp = p->ifp->info;
 134                 vc = nhrp_vc_get(&nifp->nbma, &p->vc->remote.nbma, 1);
 135                 if (vc && p->vc != vc) {
 136                         nhrp_vc_notify_del(p->vc, &p->vc_notifier);
 137                         p->vc = vc;
 138                         nhrp_vc_notify_add(p->vc, &p->vc_notifier,
 139                                            nhrp_peer_vc_notify);
 140                         __nhrp_peer_check(p);
 141                 }
 142                 /* fallthru */ /* to post config update */
 143         case NOTIFY_INTERFACE_ADDRESS_CHANGED:
 144                 notifier_call(&p->notifier_list, NOTIFY_PEER_IFCONFIG_CHANGED);
 145                 break;
 146         case NOTIFY_INTERFACE_IPSEC_CHANGED:
 147                 __nhrp_peer_check(p);
 148                 notifier_call(&p->notifier_list, NOTIFY_PEER_IFCONFIG_CHANGED);
 149                 break;
 150         case NOTIFY_INTERFACE_MTU_CHANGED:
 151                 notifier_call(&p->notifier_list, NOTIFY_PEER_MTU_CHANGED);
 152                 break;
 153         }
 154         nhrp_peer_unref(p);
 155 }
 156
 157 static unsigned int nhrp_peer_key(const void *peer_data)
 158 {
 159         const struct nhrp_peer *p = peer_data;
 160         return sockunion_hash(&p->vc->remote.nbma);
 161 }
 162
 163 static bool nhrp_peer_cmp(const void *cache_data, const void *key_data)
 164 {
 165         const struct nhrp_peer *a = cache_data;
 166         const struct nhrp_peer *b = key_data;
 167
 168         return a->ifp == b->ifp && a->vc == b->vc;
 169 }
 170
 171 static void *nhrp_peer_create(void *data)
 172 {
 173         struct nhrp_peer *p, *key = data;
 174
 175         p = XMALLOC(MTYPE_NHRP_PEER, sizeof(*p));
 176
 177         *p = (struct nhrp_peer){
 178                 .ref = 0,
 179                 .ifp = key->ifp,
 180                 .vc = key->vc,
 181                 .notifier_list = NOTIFIER_LIST_INITIALIZER(&p->notifier_list),
 182         };
 183         nhrp_vc_notify_add(p->vc, &p->vc_notifier, nhrp_peer_vc_notify);
 184         nhrp_interface_notify_add(p->ifp, &p->ifp_notifier,
 185                                   nhrp_peer_ifp_notify);
 186
 187         return p;
 188 }
 189
 190 static void do_peer_hash_free(void *hb_data)
 191 {
 192         struct nhrp_peer *p = (struct nhrp_peer *)hb_data;
 193
 194         nhrp_peer_check_delete(p);
 195 }
 196
 197 void nhrp_peer_interface_del(struct interface *ifp)
 198 {
 199         struct nhrp_interface *nifp = ifp->info;
 200
 201         debugf(NHRP_DEBUG_COMMON, "Cleaning up undeleted peer entries (%lu)",
 202                nifp->peer_hash ? nifp->peer_hash->count : 0);
 203
 204         hash_clean_and_free(&nifp->peer_hash, do_peer_hash_free);
 205 }
 206
 207 struct nhrp_peer *nhrp_peer_get(struct interface *ifp,
 208                                 const union sockunion *remote_nbma)
 209 {
 210         struct nhrp_interface *nifp = ifp->info;
 211         struct nhrp_peer key, *p;
 212         struct nhrp_vc *vc;
 213
 214         if (!nifp->peer_hash) {
 215                 nifp->peer_hash = hash_create(nhrp_peer_key, nhrp_peer_cmp,
 216                                               "NHRP Peer Hash");
 217                 if (!nifp->peer_hash)
 218                         return NULL;
 219         }
 220
 221         vc = nhrp_vc_get(&nifp->nbma, remote_nbma, 1);
 222         if (!vc)
 223                 return NULL;
 224
 225         key.ifp = ifp;
 226         key.vc = vc;
 227
 228         p = hash_get(nifp->peer_hash, &key, nhrp_peer_create);
 229         nhrp_peer_ref(p);
 230         if (p->ref == 1)
 231                 __nhrp_peer_check(p);
 232
 233         return p;
 234 }
 235
 236 struct nhrp_peer *nhrp_peer_ref(struct nhrp_peer *p)
 237 {
 238         if (p)
 239                 p->ref++;
 240         return p;
 241 }
 242
 243 void nhrp_peer_unref(struct nhrp_peer *p)
 244 {
 245         if (p) {
 246                 p->ref--;
 247                 nhrp_peer_check_delete(p);
 248         }
 249 }
 250
 251 static void nhrp_peer_request_timeout(struct event *t)
 252 {
 253         struct nhrp_peer *p = EVENT_ARG(t);
 254         struct nhrp_vc *vc = p->vc;
 255         struct interface *ifp = p->ifp;
 256         struct nhrp_interface *nifp = ifp->info;
 257
 258
 259         if (p->online)
 260                 return;
 261
 262         if (nifp->ipsec_fallback_profile && !p->prio
 263             && !p->fallback_requested) {
 264                 p->fallback_requested = 1;
 265                 vici_request_vc(nifp->ipsec_fallback_profile, &vc->local.nbma,
 266                                 &vc->remote.nbma, p->prio);
 267                 event_add_timer(master, nhrp_peer_request_timeout, p, 30,
 268                                 &p->t_fallback);
 269         } else {
 270                 p->requested = p->fallback_requested = 0;
 271         }
 272 }
 273
 274 static void nhrp_peer_defer_vici_request(struct event *t)
 275 {
 276         struct nhrp_peer *p = EVENT_ARG(t);
 277         struct nhrp_vc *vc = p->vc;
 278         struct interface *ifp = p->ifp;
 279         struct nhrp_interface *nifp = ifp->info;
 280
 281         EVENT_OFF(p->t_timer);
 282
 283         if (p->online) {
 284                 debugf(NHRP_DEBUG_COMMON,
 285                        "IPsec connection to %pSU already established",
 286                        &vc->remote.nbma);
 287         } else {
 288                 vici_request_vc(nifp->ipsec_profile, &vc->local.nbma,
 289                                 &vc->remote.nbma, p->prio);
 290                 event_add_timer(master, nhrp_peer_request_timeout, p,
 291                                 (nifp->ipsec_fallback_profile && !p->prio) ? 15
 292                                                                            : 30,
 293                                 &p->t_fallback);
 294         }
 295 }
 296
 297 int nhrp_peer_check(struct nhrp_peer *p, int establish)
 298 {
 299         struct nhrp_vc *vc = p->vc;
 300         struct interface *ifp = p->ifp;
 301         struct nhrp_interface *nifp = ifp->info;
 302
 303         if (p->online)
 304                 return 1;
 305         if (!establish)
 306                 return 0;
 307         if (p->requested)
 308                 return 0;
 309         if (!nifp->ipsec_profile)
 310                 return 0;
 311         if (sockunion_family(&vc->local.nbma) == AF_UNSPEC)
 312                 return 0;
 313         if (vc->ipsec)
 314                 return 1;
 315
 316         p->prio = establish > 1;
 317         p->requested = 1;
 318
 319         /* All NHRP registration requests are prioritized */
 320         if (p->prio) {
 321                 vici_request_vc(nifp->ipsec_profile, &vc->local.nbma,
 322                                 &vc->remote.nbma, p->prio);
 323                 event_add_timer(master, nhrp_peer_request_timeout, p,
 324                                 (nifp->ipsec_fallback_profile && !p->prio) ? 15
 325                                                                            : 30,
 326                                 &p->t_fallback);
 327         } else {
 328                 /* Maximum timeout is 1 second */
 329                 int r_time_ms = frr_weak_random() % 1000;
 330
 331                 debugf(NHRP_DEBUG_COMMON,
 332                        "Initiating IPsec connection request to %pSU after %d ms:",
 333                        &vc->remote.nbma, r_time_ms);
 334                 event_add_timer_msec(master, nhrp_peer_defer_vici_request, p,
 335                                      r_time_ms, &p->t_timer);
 336         }
 337
 338         return 0;
 339 }
 340
 341 void nhrp_peer_notify_add(struct nhrp_peer *p, struct notifier_block *n,
 342                           notifier_fn_t fn)
 343 {
 344         notifier_add(n, &p->notifier_list, fn);
 345 }
 346
 347 void nhrp_peer_notify_del(struct nhrp_peer *p, struct notifier_block *n)
 348 {
 349         notifier_del(n, &p->notifier_list);
 350         nhrp_peer_check_delete(p);
 351 }
 352
 353 void nhrp_peer_send(struct nhrp_peer *p, struct zbuf *zb)
 354 {
 355         nhrp_packet_debug(zb, "Send");
 356
 357         if (!p->online)
 358                 return;
 359
 360         debugf(NHRP_DEBUG_KERNEL, "PACKET: Send %pSU -> %pSU",
 361                &p->vc->local.nbma, &p->vc->remote.nbma);
 362
 363         os_sendmsg(zb->head, zbuf_used(zb), p->ifp->ifindex,
 364                    sockunion_get_addr(&p->vc->remote.nbma),
 365                    sockunion_get_addrlen(&p->vc->remote.nbma), ETH_P_NHRP);
 366         zbuf_reset(zb);
 367 }
 368
 369 static void nhrp_process_nat_extension(struct nhrp_packet_parser *pp,
 370                                        union sockunion *proto,
 371                                        union sockunion *cie_nbma)
 372 {
 373         union sockunion cie_proto;
 374         struct zbuf payload;
 375         struct nhrp_extension_header *ext;
 376         struct zbuf *extensions;
 377
 378         if (!cie_nbma)
 379                 return;
 380
 381         sockunion_family(cie_nbma) = AF_UNSPEC;
 382
 383         if (!proto || sockunion_family(proto) == AF_UNSPEC)
 384                 return;
 385
 386         /* Handle extensions */
 387         extensions = zbuf_alloc(zbuf_used(&pp->extensions));
 388         if (extensions) {
 389                 zbuf_copy_peek(extensions, &pp->extensions,
 390                                  zbuf_used(&pp->extensions));
 391                 while ((ext = nhrp_ext_pull(extensions, &payload)) != NULL) {
 392                         switch (htons(ext->type)
 393                                 & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
 394                         case NHRP_EXTENSION_NAT_ADDRESS:
 395                                 /* Process the NBMA and proto address in NAT
 396                                  * extension and update the cache without which
 397                                  * the neighbor table in the kernel contains the
 398                                  * source NBMA address which is not reachable
 399                                  * since it is behind a NAT device
 400                                  */
 401                                 debugf(NHRP_DEBUG_COMMON,
 402                                        "shortcut res_resp: Processing NAT Extension for %pSU",
 403                                        proto);
 404                                 while (nhrp_cie_pull(&payload, pp->hdr,
 405                                                      cie_nbma, &cie_proto)) {
 406                                         if (sockunion_family(&cie_proto)
 407                                             == AF_UNSPEC)
 408                                                 continue;
 409
 410                                         if (!sockunion_cmp(proto, &cie_proto)) {
 411                                                 debugf(NHRP_DEBUG_COMMON,
 412                                                        "cie_nbma for proto %pSU is %pSU",
 413                                                        proto, cie_nbma);
 414                                                 break;
 415                                         }
 416                                 }
 417                         }
 418                 }
 419                 zbuf_free(extensions);
 420         }
 421 }
 422
 423 static void nhrp_handle_resolution_req(struct nhrp_packet_parser *pp)
 424 {
 425         struct interface *ifp = pp->ifp;
 426         struct zbuf *zb, payload;
 427         struct nhrp_packet_header *hdr;
 428         struct nhrp_cie_header *cie;
 429         struct nhrp_extension_header *ext;
 430         struct nhrp_cache *c;
 431         union sockunion cie_nbma, cie_nbma_nat, cie_proto, *proto_addr,
 432                 *nbma_addr, *claimed_nbma_addr;
 433         int holdtime, prefix_len, hostprefix_len;
 434         struct nhrp_interface *nifp = ifp->info;
 435         struct nhrp_peer *peer;
 436         size_t paylen;
 437
 438         if (!(pp->if_ad->flags & NHRP_IFF_SHORTCUT)) {
 439                 debugf(NHRP_DEBUG_COMMON, "Shortcuts disabled");
 440                 /* FIXME: Send error indication? */
 441                 return;
 442         }
 443
 444         if (pp->if_ad->network_id && pp->route_type == NHRP_ROUTE_OFF_NBMA
 445             && pp->route_prefix.prefixlen < 8) {
 446                 debugf(NHRP_DEBUG_COMMON,
 447                        "Shortcut to more generic than /8 dropped");
 448                 return;
 449         }
 450
 451         debugf(NHRP_DEBUG_COMMON, "Parsing and replying to Resolution Req");
 452
 453         if (nhrp_route_address(ifp, &pp->src_proto, NULL, &peer)
 454             != NHRP_ROUTE_NBMA_NEXTHOP)
 455                 return;
 456
 457         /* Copy payload CIE */
 458         hostprefix_len = 8 * sockunion_get_addrlen(&pp->if_ad->addr);
 459         paylen = zbuf_used(&pp->payload);
 460         debugf(NHRP_DEBUG_COMMON, "shortcut res_rep: paylen %zu", paylen);
 461
 462         while ((cie = nhrp_cie_pull(&pp->payload, pp->hdr, &cie_nbma,
 463                                     &cie_proto))
 464                != NULL) {
 465                 prefix_len = cie->prefix_length;
 466                 debugf(NHRP_DEBUG_COMMON,
 467                        "shortcut res_rep: parsing CIE with prefixlen=%u",
 468                        prefix_len);
 469                 if (prefix_len == 0 || prefix_len >= hostprefix_len)
 470                         prefix_len = hostprefix_len;
 471
 472                 if (prefix_len != hostprefix_len
 473                     && !(pp->hdr->flags
 474                          & htons(NHRP_FLAG_REGISTRATION_UNIQUE))) {
 475                         cie->code = NHRP_CODE_BINDING_NON_UNIQUE;
 476                         continue;
 477                 }
 478
 479                 /* We currently support only unique prefix registrations */
 480                 if (prefix_len != hostprefix_len) {
 481                         cie->code = NHRP_CODE_ADMINISTRATIVELY_PROHIBITED;
 482                         continue;
 483                 }
 484
 485                 proto_addr = (sockunion_family(&cie_proto) == AF_UNSPEC)
 486                                      ? &pp->src_proto
 487                                      : &cie_proto;
 488
 489                 /* Check for this proto_addr in NHRP_NAT_EXTENSION */
 490                 nhrp_process_nat_extension(pp, proto_addr, &cie_nbma_nat);
 491
 492                 if (sockunion_family(&cie_nbma_nat) == AF_UNSPEC) {
 493                         /* It may be possible that this resolution reply is
 494                          * coming directly from NATTED Spoke and there is not
 495                          * NAT Extension present
 496                          */
 497                         debugf(NHRP_DEBUG_COMMON,
 498                                "shortcut res_rep: No NAT Extension for %pSU",
 499                                proto_addr);
 500
 501                         if (!sockunion_same(&pp->src_nbma,
 502                                             &pp->peer->vc->remote.nbma)
 503                             && !nhrp_nhs_match_ip(&pp->peer->vc->remote.nbma,
 504                                                   nifp)) {
 505                                 cie_nbma_nat = pp->peer->vc->remote.nbma;
 506                                 debugf(NHRP_DEBUG_COMMON,
 507                                        "shortcut res_rep: NAT detected using %pSU as cie_nbma",
 508                                        &cie_nbma_nat);
 509                         }
 510                 }
 511
 512                 if (sockunion_family(&cie_nbma_nat) != AF_UNSPEC)
 513                         nbma_addr = &cie_nbma_nat;
 514                 else if (sockunion_family(&cie_nbma) != AF_UNSPEC)
 515                         nbma_addr = &cie_nbma;
 516                 else
 517                         nbma_addr = &pp->src_nbma;
 518
 519                 if (sockunion_family(&cie_nbma) != AF_UNSPEC)
 520                         claimed_nbma_addr = &cie_nbma;
 521                 else
 522                         claimed_nbma_addr = &pp->src_nbma;
 523
 524                 holdtime = htons(cie->holding_time);
 525                 debugf(NHRP_DEBUG_COMMON,
 526                        "shortcut res_rep: holdtime is %u (if 0, using %u)",
 527                        holdtime, pp->if_ad->holdtime);
 528                 if (!holdtime)
 529                         holdtime = pp->if_ad->holdtime;
 530
 531                 c = nhrp_cache_get(ifp, proto_addr, 1);
 532                 if (!c) {
 533                         debugf(NHRP_DEBUG_COMMON,
 534                                "shortcut res_rep: no cache found");
 535                         cie->code = NHRP_CODE_INSUFFICIENT_RESOURCES;
 536                         continue;
 537                 }
 538
 539                 debugf(NHRP_DEBUG_COMMON,
 540                        "shortcut res_rep: updating binding for nmba addr %pSU",
 541                        nbma_addr);
 542                 if (!nhrp_cache_update_binding(
 543                             c, NHRP_CACHE_DYNAMIC, holdtime,
 544                             nhrp_peer_get(pp->ifp, nbma_addr), htons(cie->mtu),
 545                             nbma_addr, claimed_nbma_addr)) {
 546                         cie->code = NHRP_CODE_ADMINISTRATIVELY_PROHIBITED;
 547                         continue;
 548                 }
 549
 550                 cie->code = NHRP_CODE_SUCCESS;
 551         }
 552
 553         /* Create reply */
 554         zb = zbuf_alloc(1500);
 555         hdr = nhrp_packet_push(zb, NHRP_PACKET_RESOLUTION_REPLY, &pp->src_nbma,
 556                                &pp->src_proto, &pp->dst_proto);
 557
 558         /* Copied information from request */
 559         hdr->flags = pp->hdr->flags
 560                      & htons(NHRP_FLAG_RESOLUTION_SOURCE_IS_ROUTER
 561                              | NHRP_FLAG_RESOLUTION_SOURCE_STABLE);
 562         hdr->flags |= htons(NHRP_FLAG_RESOLUTION_DESTINATION_STABLE
 563                             | NHRP_FLAG_RESOLUTION_AUTHORATIVE);
 564         hdr->u.request_id = pp->hdr->u.request_id;
 565
 566         /* CIE payload for the reply packet */
 567         cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, &nifp->nbma,
 568                             &pp->if_ad->addr);
 569         cie->holding_time = htons(pp->if_ad->holdtime);
 570         cie->mtu = htons(pp->if_ad->mtu);
 571         if (pp->if_ad->network_id && pp->route_type == NHRP_ROUTE_OFF_NBMA)
 572                 cie->prefix_length = pp->route_prefix.prefixlen;
 573         else
 574                 cie->prefix_length =
 575                         8 * sockunion_get_addrlen(&pp->if_ad->addr);
 576
 577         /* Handle extensions */
 578         while ((ext = nhrp_ext_pull(&pp->extensions, &payload)) != NULL) {
 579                 switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
 580                 case NHRP_EXTENSION_NAT_ADDRESS:
 581                         ext = nhrp_ext_push(zb, hdr,
 582                                             NHRP_EXTENSION_NAT_ADDRESS);
 583                         if (!ext)
 584                                 goto err;
 585                         if (sockunion_family(&nifp->nat_nbma) != AF_UNSPEC) {
 586                                 cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS,
 587                                                     &nifp->nat_nbma,
 588                                                     &pp->if_ad->addr);
 589                                 if (!cie)
 590                                         goto err;
 591                                 cie->prefix_length =
 592                                         8 * sockunion_get_addrlen(
 593                                                         &pp->if_ad->addr);
 594
 595                                 cie->mtu = htons(pp->if_ad->mtu);
 596                                 nhrp_ext_complete(zb, ext);
 597                         }
 598                         break;
 599                 default:
 600                         if (nhrp_ext_reply(zb, hdr, ifp, ext, &payload) < 0)
 601                                 goto err;
 602                         break;
 603                 }
 604         }
 605         nhrp_packet_complete(zb, hdr);
 606         nhrp_peer_send(peer, zb);
 607 err:
 608         nhrp_peer_unref(peer);
 609         zbuf_free(zb);
 610 }
 611
 612 static void nhrp_handle_registration_request(struct nhrp_packet_parser *p)
 613 {
 614         struct interface *ifp = p->ifp;
 615         struct zbuf *zb, payload;
 616         struct nhrp_packet_header *hdr;
 617         struct nhrp_cie_header *cie;
 618         struct nhrp_extension_header *ext;
 619         struct nhrp_cache *c;
 620         union sockunion cie_nbma, cie_proto, *proto_addr, *nbma_addr,
 621                 *nbma_natoa;
 622         int holdtime, prefix_len, hostprefix_len, natted = 0;
 623         size_t paylen;
 624         void *pay;
 625
 626         debugf(NHRP_DEBUG_COMMON, "Parsing and replying to Registration Req");
 627         hostprefix_len = 8 * sockunion_get_addrlen(&p->if_ad->addr);
 628
 629         if (!sockunion_same(&p->src_nbma, &p->peer->vc->remote.nbma))
 630                 natted = 1;
 631
 632         /* Create reply */
 633         zb = zbuf_alloc(1500);
 634         hdr = nhrp_packet_push(zb, NHRP_PACKET_REGISTRATION_REPLY, &p->src_nbma,
 635                                &p->src_proto, &p->if_ad->addr);
 636
 637         /* Copied information from request */
 638         hdr->flags = p->hdr->flags & htons(NHRP_FLAG_REGISTRATION_UNIQUE
 639                                            | NHRP_FLAG_REGISTRATION_NAT);
 640         hdr->u.request_id = p->hdr->u.request_id;
 641
 642         /* Copy payload CIEs */
 643         paylen = zbuf_used(&p->payload);
 644         pay = zbuf_pushn(zb, paylen);
 645         if (!pay)
 646                 goto err;
 647         memcpy(pay, zbuf_pulln(&p->payload, paylen), paylen);
 648         zbuf_init(&payload, pay, paylen, paylen);
 649
 650         while ((cie = nhrp_cie_pull(&payload, hdr, &cie_nbma, &cie_proto))
 651                != NULL) {
 652                 prefix_len = cie->prefix_length;
 653                 if (prefix_len == 0 || prefix_len >= hostprefix_len)
 654                         prefix_len = hostprefix_len;
 655
 656                 if (prefix_len != hostprefix_len
 657                     && !(p->hdr->flags
 658                          & htons(NHRP_FLAG_REGISTRATION_UNIQUE))) {
 659                         cie->code = NHRP_CODE_BINDING_NON_UNIQUE;
 660                         continue;
 661                 }
 662
 663                 /* We currently support only unique prefix registrations */
 664                 if (prefix_len != hostprefix_len) {
 665                         cie->code = NHRP_CODE_ADMINISTRATIVELY_PROHIBITED;
 666                         continue;
 667                 }
 668
 669                 proto_addr = (sockunion_family(&cie_proto) == AF_UNSPEC)
 670                                      ? &p->src_proto
 671                                      : &cie_proto;
 672                 nbma_addr = (sockunion_family(&cie_nbma) == AF_UNSPEC)
 673                                     ? &p->src_nbma
 674                                     : &cie_nbma;
 675                 nbma_natoa = NULL;
 676                 if (natted) {
 677                         nbma_natoa =
 678                                 (sockunion_family(&p->peer->vc->remote.nbma)
 679                                  == AF_UNSPEC)
 680                                         ? nbma_addr
 681                                         : &p->peer->vc->remote.nbma;
 682                 }
 683
 684                 holdtime = htons(cie->holding_time);
 685                 if (!holdtime)
 686                         holdtime = p->if_ad->holdtime;
 687
 688                 c = nhrp_cache_get(ifp, proto_addr, 1);
 689                 if (!c) {
 690                         cie->code = NHRP_CODE_INSUFFICIENT_RESOURCES;
 691                         continue;
 692                 }
 693
 694                 if (!nhrp_cache_update_binding(c, NHRP_CACHE_DYNAMIC, holdtime,
 695                                                nhrp_peer_ref(p->peer),
 696                                                htons(cie->mtu), nbma_natoa,
 697                                                nbma_addr)) {
 698                         cie->code = NHRP_CODE_ADMINISTRATIVELY_PROHIBITED;
 699                         continue;
 700                 }
 701
 702                 cie->code = NHRP_CODE_SUCCESS;
 703         }
 704
 705         /* Handle extensions */
 706         while ((ext = nhrp_ext_pull(&p->extensions, &payload)) != NULL) {
 707                 switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
 708                 case NHRP_EXTENSION_NAT_ADDRESS:
 709                         ext = nhrp_ext_push(zb, hdr,
 710                                             NHRP_EXTENSION_NAT_ADDRESS);
 711                         if (!ext)
 712                                 goto err;
 713                         zbuf_copy(zb, &payload, zbuf_used(&payload));
 714                         if (natted) {
 715                                 cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS,
 716                                                     &p->peer->vc->remote.nbma,
 717                                                     &p->src_proto);
 718                                 cie->prefix_length =
 719                                         8 * sockunion_get_addrlen(
 720                                                     &p->if_ad->addr);
 721                                 cie->mtu = htons(p->if_ad->mtu);
 722                         }
 723                         nhrp_ext_complete(zb, ext);
 724                         break;
 725                 default:
 726                         if (nhrp_ext_reply(zb, hdr, ifp, ext, &payload) < 0)
 727                                 goto err;
 728                         break;
 729                 }
 730         }
 731
 732         nhrp_packet_complete(zb, hdr);
 733         nhrp_peer_send(p->peer, zb);
 734 err:
 735         zbuf_free(zb);
 736 }
 737
 738 static int parse_ether_packet(struct zbuf *zb, uint16_t protocol_type,
 739                               union sockunion *src, union sockunion *dst)
 740 {
 741         switch (protocol_type) {
 742         case ETH_P_IP: {
 743                 struct iphdr *iph = zbuf_pull(zb, struct iphdr);
 744                 if (iph) {
 745                         if (src)
 746                                 sockunion_set(src, AF_INET,
 747                                               (uint8_t *)&iph->saddr,
 748                                               sizeof(iph->saddr));
 749                         if (dst)
 750                                 sockunion_set(dst, AF_INET,
 751                                               (uint8_t *)&iph->daddr,
 752                                               sizeof(iph->daddr));
 753                 }
 754         } break;
 755         case ETH_P_IPV6: {
 756                 struct ipv6hdr *iph = zbuf_pull(zb, struct ipv6hdr);
 757                 if (iph) {
 758                         if (src)
 759                                 sockunion_set(src, AF_INET6,
 760                                               (uint8_t *)&iph->saddr,
 761                                               sizeof(iph->saddr));
 762                         if (dst)
 763                                 sockunion_set(dst, AF_INET6,
 764                                               (uint8_t *)&iph->daddr,
 765                                               sizeof(iph->daddr));
 766                 }
 767         } break;
 768         default:
 769                 return 0;
 770         }
 771         return 1;
 772 }
 773
 774 void nhrp_peer_send_indication(struct interface *ifp, uint16_t protocol_type,
 775                                struct zbuf *pkt)
 776 {
 777         union sockunion dst;
 778         struct zbuf *zb, payload;
 779         struct nhrp_interface *nifp = ifp->info;
 780         struct nhrp_afi_data *if_ad;
 781         struct nhrp_packet_header *hdr;
 782         struct nhrp_peer *p;
 783
 784         if (!nifp->enabled)
 785                 return;
 786
 787         payload = *pkt;
 788         if (!parse_ether_packet(&payload, protocol_type, &dst, NULL))
 789                 return;
 790
 791         if (nhrp_route_address(ifp, &dst, NULL, &p) != NHRP_ROUTE_NBMA_NEXTHOP)
 792                 return;
 793
 794         if_ad = &nifp->afi[family2afi(sockunion_family(&dst))];
 795         if (!(if_ad->flags & NHRP_IFF_REDIRECT)) {
 796                 debugf(NHRP_DEBUG_COMMON,
 797                        "Send Traffic Indication to %pSU about packet to %pSU ignored",
 798                        &p->vc->remote.nbma, &dst);
 799                 return;
 800         }
 801
 802         debugf(NHRP_DEBUG_COMMON,
 803                "Send Traffic Indication to %pSU (online=%d) about packet to %pSU",
 804                &p->vc->remote.nbma, p->online, &dst);
 805
 806         /* Create reply */
 807         zb = zbuf_alloc(1500);
 808         hdr = nhrp_packet_push(zb, NHRP_PACKET_TRAFFIC_INDICATION, &nifp->nbma,
 809                                &if_ad->addr, &dst);
 810         hdr->hop_count = 1;
 811
 812         /* Payload is the packet causing indication */
 813         zbuf_copy(zb, pkt, zbuf_used(pkt));
 814         nhrp_packet_complete(zb, hdr);
 815         nhrp_peer_send(p, zb);
 816         nhrp_peer_unref(p);
 817         zbuf_free(zb);
 818 }
 819
 820 static void nhrp_handle_error_ind(struct nhrp_packet_parser *pp)
 821 {
 822         struct zbuf origmsg = pp->payload;
 823         struct nhrp_packet_header *hdr;
 824         struct nhrp_reqid *reqid;
 825         union sockunion src_nbma, src_proto, dst_proto;
 826
 827         hdr = nhrp_packet_pull(&origmsg, &src_nbma, &src_proto, &dst_proto);
 828         if (!hdr)
 829                 return;
 830
 831         debugf(NHRP_DEBUG_COMMON,
 832                "Error Indication from %pSU about packet to %pSU ignored",
 833                &pp->src_proto, &dst_proto);
 834
 835         reqid = nhrp_reqid_lookup(&nhrp_packet_reqid, htonl(hdr->u.request_id));
 836         if (reqid)
 837                 reqid->cb(reqid, pp);
 838 }
 839
 840 static void nhrp_handle_traffic_ind(struct nhrp_packet_parser *p)
 841 {
 842         union sockunion dst;
 843
 844         if (!parse_ether_packet(&p->payload, htons(p->hdr->protocol_type), NULL,
 845                                 &dst))
 846                 return;
 847
 848         debugf(NHRP_DEBUG_COMMON,
 849                "Traffic Indication from %pSU about packet to %pSU: %s",
 850                &p->src_proto, &dst,
 851                (p->if_ad->flags & NHRP_IFF_SHORTCUT) ? "trying shortcut"
 852                                                      : "ignored");
 853
 854         if (p->if_ad->flags & NHRP_IFF_SHORTCUT)
 855                 nhrp_shortcut_initiate(&dst);
 856 }
 857
 858 enum packet_type_t {
 859         PACKET_UNKNOWN = 0,
 860         PACKET_REQUEST,
 861         PACKET_REPLY,
 862         PACKET_INDICATION,
 863 };
 864
 865 static struct {
 866         enum packet_type_t type;
 867         const char *name;
 868         void (*handler)(struct nhrp_packet_parser *);
 869 } packet_types[] = {[0] =
 870                             {
 871                                     .type = PACKET_UNKNOWN,
 872                                     .name = "UNKNOWN",
 873                             },
 874                     [NHRP_PACKET_RESOLUTION_REQUEST] =
 875                             {
 876                                     .type = PACKET_REQUEST,
 877                                     .name = "Resolution-Request",
 878                                     .handler = nhrp_handle_resolution_req,
 879                             },
 880                     [NHRP_PACKET_RESOLUTION_REPLY] =
 881                             {
 882                                     .type = PACKET_REPLY,
 883                                     .name = "Resolution-Reply",
 884                             },
 885                     [NHRP_PACKET_REGISTRATION_REQUEST] =
 886                             {
 887                                     .type = PACKET_REQUEST,
 888                                     .name = "Registration-Request",
 889                                     .handler = nhrp_handle_registration_request,
 890                             },
 891                     [NHRP_PACKET_REGISTRATION_REPLY] =
 892                             {
 893                                     .type = PACKET_REPLY,
 894                                     .name = "Registration-Reply",
 895                             },
 896                     [NHRP_PACKET_PURGE_REQUEST] =
 897                             {
 898                                     .type = PACKET_REQUEST,
 899                                     .name = "Purge-Request",
 900                             },
 901                     [NHRP_PACKET_PURGE_REPLY] =
 902                             {
 903                                     .type = PACKET_REPLY,
 904                                     .name = "Purge-Reply",
 905                             },
 906                     [NHRP_PACKET_ERROR_INDICATION] =
 907                             {
 908                                     .type = PACKET_INDICATION,
 909                                     .name = "Error-Indication",
 910                                     .handler = nhrp_handle_error_ind,
 911                             },
 912                     [NHRP_PACKET_TRAFFIC_INDICATION] = {
 913                             .type = PACKET_INDICATION,
 914                             .name = "Traffic-Indication",
 915                             .handler = nhrp_handle_traffic_ind,
 916                     }};
 917
 918 static void nhrp_peer_forward(struct nhrp_peer *p,
 919                               struct nhrp_packet_parser *pp)
 920 {
 921         struct zbuf *zb, *zb_copy, extpl;
 922         struct nhrp_packet_header *hdr;
 923         struct nhrp_extension_header *ext, *dst;
 924         struct nhrp_cie_header *cie;
 925         struct nhrp_interface *nifp = pp->ifp->info;
 926         struct nhrp_afi_data *if_ad = pp->if_ad;
 927         union sockunion cie_nbma, cie_protocol, cie_protocol_mandatory, *proto;
 928         uint16_t type, len;
 929         struct nhrp_cache *c;
 930
 931         if (pp->hdr->hop_count == 0)
 932                 return;
 933
 934         /* Create forward packet - copy header */
 935         zb = zbuf_alloc(1500);
 936         zb_copy = zbuf_alloc(1500);
 937
 938         hdr = nhrp_packet_push(zb, pp->hdr->type, &pp->src_nbma, &pp->src_proto,
 939                                &pp->dst_proto);
 940         hdr->flags = pp->hdr->flags;
 941         hdr->hop_count = pp->hdr->hop_count - 1;
 942         hdr->u.request_id = pp->hdr->u.request_id;
 943
 944         /* Copy payload */
 945         zbuf_copy_peek(zb_copy, &pp->payload, zbuf_used(&pp->payload));
 946         zbuf_copy(zb, &pp->payload, zbuf_used(&pp->payload));
 947
 948         /* Get CIE Extension from Mandatory part */
 949         sockunion_family(&cie_protocol_mandatory) = AF_UNSPEC;
 950         nhrp_cie_pull(zb_copy, pp->hdr, &cie_nbma, &cie_protocol_mandatory);
 951
 952         /* Copy extensions */
 953         while ((ext = nhrp_ext_pull(&pp->extensions, &extpl)) != NULL) {
 954                 type = htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY;
 955                 len = htons(ext->length);
 956
 957                 if (type == NHRP_EXTENSION_END)
 958                         break;
 959
 960                 dst = nhrp_ext_push(zb, hdr, htons(ext->type));
 961                 if (!dst)
 962                         goto err;
 963
 964                 switch (type) {
 965                 case NHRP_EXTENSION_FORWARD_TRANSIT_NHS:
 966                 case NHRP_EXTENSION_REVERSE_TRANSIT_NHS:
 967                         zbuf_put(zb, extpl.head, len);
 968                         if ((type == NHRP_EXTENSION_REVERSE_TRANSIT_NHS)
 969                             == (packet_types[hdr->type].type == PACKET_REPLY)) {
 970                                 /* Check NHS list for forwarding loop */
 971                                 while (nhrp_cie_pull(&extpl, pp->hdr,
 972                                                      &cie_nbma,
 973                                                      &cie_protocol) != NULL) {
 974                                         if (sockunion_same(&p->vc->remote.nbma,
 975                                                            &cie_nbma))
 976                                                 goto err;
 977                                 }
 978                                 /* Append our selves to the list */
 979                                 cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS,
 980                                                     &nifp->nbma, &if_ad->addr);
 981                                 if (!cie)
 982                                         goto err;
 983                                 cie->mtu = htons(if_ad->mtu);
 984                                 cie->holding_time = htons(if_ad->holdtime);
 985                         }
 986                         break;
 987                 case NHRP_EXTENSION_NAT_ADDRESS:
 988                         c = NULL;
 989                         proto = NULL;
 990
 991                         /* If NAT extension is empty then attempt to populate
 992                          * it with cached NBMA information
 993                          */
 994                         if (len == 0) {
 995                                 if (packet_types[hdr->type].type
 996                                     == PACKET_REQUEST) {
 997                                         debugf(NHRP_DEBUG_COMMON,
 998                                                "Processing NHRP_EXTENSION_NAT_ADDRESS while forwarding the request packet");
 999                                         proto = &pp->src_proto;
1000                                 } else if (packet_types[hdr->type].type
1001                                            == PACKET_REPLY) {
1002                                         debugf(NHRP_DEBUG_COMMON,
1003                                                "Processing NHRP_EXTENSION_NAT_ADDRESS while forwarding the reply packet");
1004                                         /* For reply packet use protocol
1005                                          * specified in CIE of mandatory part
1006                                          * for cache lookup
1007                                          */
1008                                         if (sockunion_family(
1009                                                     &cie_protocol_mandatory)
1010                                             != AF_UNSPEC)
1011                                                 proto = &cie_protocol_mandatory;
1012                                 }
1013                         }
1014
1015                         if (proto) {
1016                                 debugf(NHRP_DEBUG_COMMON, "Proto is %pSU",
1017                                        proto);
1018                                 c = nhrp_cache_get(nifp->ifp, proto, 0);
1019                         }
1020
1021                         if (c) {
1022                                 debugf(NHRP_DEBUG_COMMON,
1023                                        "c->cur.remote_nbma_natoa is %pSU",
1024                                        &c->cur.remote_nbma_natoa);
1025                                 if (sockunion_family(&c->cur.remote_nbma_natoa)
1026                                     != AF_UNSPEC) {
1027                                         cie = nhrp_cie_push(
1028                                                 zb,
1029                                                 NHRP_CODE_SUCCESS,
1030                                                 &c->cur.remote_nbma_natoa,
1031                                                 proto);
1032                                         if (!cie)
1033                                                 goto err;
1034                                 }
1035                         } else {
1036                                 if (proto)
1037                                         debugf(NHRP_DEBUG_COMMON,
1038                                                "No cache entry for proto %pSU",
1039                                                proto);
1040                                 /* Copy existing NAT extension to new packet if
1041                                  * either it was already not-empty, or we do not
1042                                  * have valid cache information
1043                                  */
1044                                 zbuf_put(zb, extpl.head, len);
1045                         }
1046                         break;
1047                 default:
1048                         if (htons(ext->type) & NHRP_EXTENSION_FLAG_COMPULSORY)
1049                                 /* FIXME: RFC says to just copy, but not
1050                                  * append our selves to the transit NHS list
1051                                  */
1052                                 goto err;
1053                 /* fallthru */
1054                 case NHRP_EXTENSION_RESPONDER_ADDRESS:
1055                         /* Supported compulsory extensions, and any
1056                          * non-compulsory that is not explicitly handled,
1057                          * should be just copied.
1058                          */
1059                         zbuf_copy(zb, &extpl, len);
1060                         break;
1061                 }
1062                 nhrp_ext_complete(zb, dst);
1063         }
1064
1065         nhrp_packet_complete(zb, hdr);
1066         nhrp_peer_send(p, zb);
1067         zbuf_free(zb);
1068         zbuf_free(zb_copy);
1069         return;
1070 err:
1071         nhrp_packet_debug(pp->pkt, "FWD-FAIL");
1072         zbuf_free(zb);
1073         zbuf_free(zb_copy);
1074 }
1075
1076 static void nhrp_packet_debug(struct zbuf *zb, const char *dir)
1077 {
1078         union sockunion src_nbma, src_proto, dst_proto;
1079         struct nhrp_packet_header *hdr;
1080         struct zbuf zhdr;
1081         int reply;
1082
1083         if (likely(!(debug_flags & NHRP_DEBUG_COMMON)))
1084                 return;
1085
1086         zbuf_init(&zhdr, zb->buf, zb->tail - zb->buf, zb->tail - zb->buf);
1087         hdr = nhrp_packet_pull(&zhdr, &src_nbma, &src_proto, &dst_proto);
1088
1089         reply = packet_types[hdr->type].type == PACKET_REPLY;
1090         debugf(NHRP_DEBUG_COMMON, "%s %s(%d) %pSU -> %pSU", dir,
1091                (packet_types[hdr->type].name ? packet_types[hdr->type].name
1092                                              : "Unknown"),
1093                hdr->type, reply ? &dst_proto : &src_proto,
1094                reply ? &src_proto : &dst_proto);
1095 }
1096
1097 static int proto2afi(uint16_t proto)
1098 {
1099         switch (proto) {
1100         case ETH_P_IP:
1101                 return AFI_IP;
1102         case ETH_P_IPV6:
1103                 return AFI_IP6;
1104         }
1105         return AF_UNSPEC;
1106 }
1107
1108 struct nhrp_route_info {
1109         int local;
1110         struct interface *ifp;
1111         struct nhrp_vc *vc;
1112 };
1113
1114 void nhrp_peer_recv(struct nhrp_peer *p, struct zbuf *zb)
1115 {
1116         struct nhrp_packet_header *hdr;
1117         struct nhrp_vc *vc = p->vc;
1118         struct interface *ifp = p->ifp;
1119         struct nhrp_interface *nifp = ifp->info;
1120         struct nhrp_packet_parser pp;
1121         struct nhrp_peer *peer = NULL;
1122         struct nhrp_reqid *reqid;
1123         const char *info = NULL;
1124         union sockunion *target_addr;
1125         unsigned paylen, extoff, extlen, realsize;
1126         afi_t nbma_afi, proto_afi;
1127
1128         debugf(NHRP_DEBUG_KERNEL, "PACKET: Recv %pSU -> %pSU", &vc->remote.nbma,
1129                &vc->local.nbma);
1130
1131         if (!p->online) {
1132                 info = "peer not online";
1133                 goto drop;
1134         }
1135
1136         if (nhrp_packet_calculate_checksum(zb->head, zbuf_used(zb)) != 0) {
1137                 info = "bad checksum";
1138                 goto drop;
1139         }
1140
1141         realsize = zbuf_used(zb);
1142         hdr = nhrp_packet_pull(zb, &pp.src_nbma, &pp.src_proto, &pp.dst_proto);
1143         if (!hdr) {
1144                 info = "corrupt header";
1145                 goto drop;
1146         }
1147
1148         pp.ifp = ifp;
1149         pp.pkt = zb;
1150         pp.hdr = hdr;
1151         pp.peer = p;
1152
1153         nbma_afi = htons(hdr->afnum);
1154         proto_afi = proto2afi(htons(hdr->protocol_type));
1155         if (hdr->type > NHRP_PACKET_MAX || hdr->version != NHRP_VERSION_RFC2332
1156             || nbma_afi >= AFI_MAX || proto_afi == AF_UNSPEC
1157             || packet_types[hdr->type].type == PACKET_UNKNOWN
1158             || htons(hdr->packet_size) > realsize) {
1159                 zlog_info(
1160                         "From %pSU: error: packet type %d, version %d, AFI %d, proto %x, size %d (real size %d)",
1161                         &vc->remote.nbma, (int)hdr->type, (int)hdr->version,
1162                         (int)nbma_afi, (int)htons(hdr->protocol_type),
1163                         (int)htons(hdr->packet_size), (int)realsize);
1164                 goto drop;
1165         }
1166         pp.if_ad = &((struct nhrp_interface *)ifp->info)->afi[proto_afi];
1167
1168         extoff = htons(hdr->extension_offset);
1169         if (extoff) {
1170                 assert(zb->head > zb->buf);
1171                 uint32_t header_offset = zb->head - zb->buf;
1172                 if (extoff >= realsize) {
1173                         info = "extoff larger than packet";
1174                         goto drop;
1175                 }
1176                 if (extoff < header_offset) {
1177                         info = "extoff smaller than header offset";
1178                         goto drop;
1179                 }
1180                 paylen = extoff - header_offset;
1181         } else {
1182                 paylen = zbuf_used(zb);
1183         }
1184         zbuf_init(&pp.payload, zbuf_pulln(zb, paylen), paylen, paylen);
1185         extlen = zbuf_used(zb);
1186         zbuf_init(&pp.extensions, zbuf_pulln(zb, extlen), extlen, extlen);
1187
1188         if (!nifp->afi[proto_afi].network_id) {
1189                 info = "nhrp not enabled";
1190                 goto drop;
1191         }
1192
1193         nhrp_packet_debug(zb, "Recv");
1194
1195         /* FIXME: Check authentication here. This extension needs to be
1196          * pre-handled. */
1197
1198         /* Figure out if this is local */
1199         target_addr = (packet_types[hdr->type].type == PACKET_REPLY)
1200                               ? &pp.src_proto
1201                               : &pp.dst_proto;
1202
1203         if (sockunion_same(&pp.src_proto, &pp.dst_proto))
1204                 pp.route_type = NHRP_ROUTE_LOCAL;
1205         else
1206                 pp.route_type = nhrp_route_address(pp.ifp, target_addr,
1207                                                    &pp.route_prefix, &peer);
1208
1209         switch (pp.route_type) {
1210         case NHRP_ROUTE_LOCAL:
1211                 nhrp_packet_debug(zb, "!LOCAL");
1212                 if (packet_types[hdr->type].type == PACKET_REPLY) {
1213                         reqid = nhrp_reqid_lookup(&nhrp_packet_reqid,
1214                                                   htonl(hdr->u.request_id));
1215                         if (reqid) {
1216                                 reqid->cb(reqid, &pp);
1217                                 break;
1218                         } else {
1219                                 nhrp_packet_debug(zb, "!UNKNOWN-REQID");
1220                                 /* FIXME: send error-indication */
1221                         }
1222                 }
1223                 /* fallthru */ /* FIXME: double check, is this correct? */
1224         case NHRP_ROUTE_OFF_NBMA:
1225                 if (packet_types[hdr->type].handler) {
1226                         packet_types[hdr->type].handler(&pp);
1227                         break;
1228                 }
1229                 break;
1230         case NHRP_ROUTE_NBMA_NEXTHOP:
1231                 nhrp_peer_forward(peer, &pp);
1232                 break;
1233         case NHRP_ROUTE_BLACKHOLE:
1234                 break;
1235         }
1236
1237 drop:
1238         if (info) {
1239                 zlog_info("From %pSU: error: %s", &vc->remote.nbma, info);
1240         }
1241         if (peer)
1242                 nhrp_peer_unref(peer);
1243         zbuf_free(zb);
1244 }