nhrpd/nhrp_nhs.c

   1 /* NHRP NHC nexthop server functions (registration)
   2  * Copyright (c) 2014-2015 Timo Teräs
   3  *
   4  * This file is free software: you may copy, redistribute and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #include "zebra.h"
  11 #include "zbuf.h"
  12 #include "memory.h"
  13 #include "thread.h"
  14 #include "nhrpd.h"
  15 #include "nhrp_protocol.h"
  16
  17 DEFINE_MTYPE_STATIC(NHRPD, NHRP_NHS, "NHRP next hop server")
  18 DEFINE_MTYPE_STATIC(NHRPD, NHRP_REGISTRATION, "NHRP registration entries")
  19
  20 static int nhrp_nhs_resolve(struct thread *t);
  21 static int nhrp_reg_send_req(struct thread *t);
  22
  23 static void nhrp_reg_reply(struct nhrp_reqid *reqid, void *arg)
  24 {
  25         struct nhrp_packet_parser *p = arg;
  26         struct nhrp_registration *r =
  27                 container_of(reqid, struct nhrp_registration, reqid);
  28         struct nhrp_nhs *nhs = r->nhs;
  29         struct interface *ifp = nhs->ifp;
  30         struct nhrp_interface *nifp = ifp->info;
  31         struct nhrp_extension_header *ext;
  32         struct nhrp_cie_header *cie;
  33         struct nhrp_cache *c;
  34         struct zbuf extpl;
  35         union sockunion cie_nbma, cie_proto, *proto;
  36         char buf[64];
  37         int ok = 0, holdtime;
  38
  39         nhrp_reqid_free(&nhrp_packet_reqid, &r->reqid);
  40
  41         if (p->hdr->type != NHRP_PACKET_REGISTRATION_REPLY) {
  42                 debugf(NHRP_DEBUG_COMMON, "NHS: Registration failed");
  43                 return;
  44         }
  45
  46         debugf(NHRP_DEBUG_COMMON, "NHS: Reg.reply received");
  47
  48         ok = 1;
  49         while ((cie = nhrp_cie_pull(&p->payload, p->hdr, &cie_nbma, &cie_proto))
  50                != NULL) {
  51                 proto = sockunion_family(&cie_proto) != AF_UNSPEC
  52                                 ? &cie_proto
  53                                 : &p->src_proto;
  54                 debugf(NHRP_DEBUG_COMMON, "NHS: CIE registration: %s: %d",
  55                        sockunion2str(proto, buf, sizeof(buf)), cie->code);
  56                 if (!((cie->code == NHRP_CODE_SUCCESS)
  57                       || (cie->code == NHRP_CODE_ADMINISTRATIVELY_PROHIBITED
  58                           && nhs->hub)))
  59                         ok = 0;
  60         }
  61
  62         if (!ok)
  63                 return;
  64
  65         /* Parse extensions */
  66         sockunion_family(&nifp->nat_nbma) = AF_UNSPEC;
  67         while ((ext = nhrp_ext_pull(&p->extensions, &extpl)) != NULL) {
  68                 switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
  69                 case NHRP_EXTENSION_NAT_ADDRESS:
  70                         /* NHS adds second CIE if NAT is detected */
  71                         if (nhrp_cie_pull(&extpl, p->hdr, &cie_nbma, &cie_proto)
  72                             && nhrp_cie_pull(&extpl, p->hdr, &cie_nbma,
  73                                              &cie_proto)) {
  74                                 nifp->nat_nbma = cie_nbma;
  75                                 debugf(NHRP_DEBUG_IF,
  76                                        "%s: NAT detected, real NBMA address: %s",
  77                                        ifp->name,
  78                                        sockunion2str(&nifp->nbma, buf,
  79                                                      sizeof(buf)));
  80                         }
  81                         break;
  82                 }
  83         }
  84
  85         /* Success - schedule next registration, and route NHS */
  86         r->timeout = 2;
  87         holdtime = nifp->afi[nhs->afi].holdtime;
  88         THREAD_OFF(r->t_register);
  89
  90         /* RFC 2332 5.2.3 - Registration is recommend to be renewed
  91          * every one third of holdtime */
  92         thread_add_timer(master, nhrp_reg_send_req, r, holdtime / 3,
  93                          &r->t_register);
  94
  95         r->proto_addr = p->dst_proto;
  96         c = nhrp_cache_get(ifp, &p->dst_proto, 1);
  97         if (c)
  98                 nhrp_cache_update_binding(c, NHRP_CACHE_NHS, holdtime,
  99                                           nhrp_peer_ref(r->peer), 0, NULL);
 100 }
 101
 102 static int nhrp_reg_timeout(struct thread *t)
 103 {
 104         struct nhrp_registration *r = THREAD_ARG(t);
 105         struct nhrp_cache *c;
 106
 107         r->t_register = NULL;
 108
 109         if (r->timeout >= 16 && sockunion_family(&r->proto_addr) != AF_UNSPEC) {
 110                 nhrp_reqid_free(&nhrp_packet_reqid, &r->reqid);
 111                 c = nhrp_cache_get(r->nhs->ifp, &r->proto_addr, 0);
 112                 if (c)
 113                         nhrp_cache_update_binding(c, NHRP_CACHE_NHS, -1, NULL,
 114                                                   0, NULL);
 115                 sockunion_family(&r->proto_addr) = AF_UNSPEC;
 116         }
 117
 118         r->timeout <<= 1;
 119         if (r->timeout > 64)
 120                 r->timeout = 2;
 121         thread_add_timer_msec(master, nhrp_reg_send_req, r, 10, &r->t_register);
 122
 123         return 0;
 124 }
 125
 126 static void nhrp_reg_peer_notify(struct notifier_block *n, unsigned long cmd)
 127 {
 128         struct nhrp_registration *r =
 129                 container_of(n, struct nhrp_registration, peer_notifier);
 130         char buf[SU_ADDRSTRLEN];
 131
 132         switch (cmd) {
 133         case NOTIFY_PEER_UP:
 134         case NOTIFY_PEER_DOWN:
 135         case NOTIFY_PEER_IFCONFIG_CHANGED:
 136         case NOTIFY_PEER_MTU_CHANGED:
 137                 debugf(NHRP_DEBUG_COMMON, "NHS: Flush timer for %s",
 138                        sockunion2str(&r->peer->vc->remote.nbma, buf,
 139                                      sizeof buf));
 140                 THREAD_TIMER_OFF(r->t_register);
 141                 thread_add_timer_msec(master, nhrp_reg_send_req, r, 10,
 142                                       &r->t_register);
 143                 break;
 144         }
 145 }
 146
 147 static int nhrp_reg_send_req(struct thread *t)
 148 {
 149         struct nhrp_registration *r = THREAD_ARG(t);
 150         struct nhrp_nhs *nhs = r->nhs;
 151         char buf1[SU_ADDRSTRLEN], buf2[SU_ADDRSTRLEN];
 152         struct interface *ifp = nhs->ifp;
 153         struct nhrp_interface *nifp = ifp->info;
 154         struct nhrp_afi_data *if_ad = &nifp->afi[nhs->afi];
 155         union sockunion *dst_proto;
 156         struct zbuf *zb;
 157         struct nhrp_packet_header *hdr;
 158         struct nhrp_extension_header *ext;
 159         struct nhrp_cie_header *cie;
 160
 161         r->t_register = NULL;
 162         if (!nhrp_peer_check(r->peer, 2)) {
 163                 debugf(NHRP_DEBUG_COMMON, "NHS: Waiting link for %s",
 164                        sockunion2str(&r->peer->vc->remote.nbma, buf1,
 165                                      sizeof buf1));
 166                 thread_add_timer(master, nhrp_reg_send_req, r, 120,
 167                                  &r->t_register);
 168                 return 0;
 169         }
 170
 171         thread_add_timer(master, nhrp_reg_timeout, r, r->timeout,
 172                          &r->t_register);
 173
 174         /* RFC2332 5.2.3 NHC uses it's own address as dst if NHS is unknown */
 175         dst_proto = &nhs->proto_addr;
 176         if (sockunion_family(dst_proto) == AF_UNSPEC)
 177                 dst_proto = &if_ad->addr;
 178
 179         sockunion2str(&if_ad->addr, buf1, sizeof(buf1));
 180         sockunion2str(dst_proto, buf2, sizeof(buf2));
 181         debugf(NHRP_DEBUG_COMMON, "NHS: Register %s -> %s (timeout %d)", buf1,
 182                buf2, r->timeout);
 183
 184         /* No protocol address configured for tunnel interface */
 185         if (sockunion_family(&if_ad->addr) == AF_UNSPEC)
 186                 return 0;
 187
 188         zb = zbuf_alloc(1400);
 189         hdr = nhrp_packet_push(zb, NHRP_PACKET_REGISTRATION_REQUEST,
 190                                &nifp->nbma, &if_ad->addr, dst_proto);
 191         hdr->hop_count = 1;
 192         if (!(if_ad->flags & NHRP_IFF_REG_NO_UNIQUE))
 193                 hdr->flags |= htons(NHRP_FLAG_REGISTRATION_UNIQUE);
 194
 195         hdr->u.request_id = htonl(nhrp_reqid_alloc(&nhrp_packet_reqid,
 196                                                    &r->reqid, nhrp_reg_reply));
 197
 198         /* FIXME: push CIE for each local protocol address */
 199         cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, NULL, NULL);
 200         cie->prefix_length = 0xff;
 201         cie->holding_time = htons(if_ad->holdtime);
 202         cie->mtu = htons(if_ad->mtu);
 203
 204         nhrp_ext_request(zb, hdr, ifp);
 205
 206         /* Cisco NAT detection extension */
 207         hdr->flags |= htons(NHRP_FLAG_REGISTRATION_NAT);
 208         ext = nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);
 209         cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, &nifp->nbma, &if_ad->addr);
 210         cie->prefix_length = 8 * sockunion_get_addrlen(&if_ad->addr);
 211         nhrp_ext_complete(zb, ext);
 212
 213         nhrp_packet_complete(zb, hdr);
 214         nhrp_peer_send(r->peer, zb);
 215         zbuf_free(zb);
 216
 217         return 0;
 218 }
 219
 220 static void nhrp_reg_delete(struct nhrp_registration *r)
 221 {
 222         nhrp_peer_notify_del(r->peer, &r->peer_notifier);
 223         nhrp_peer_unref(r->peer);
 224         list_del(&r->reglist_entry);
 225         THREAD_OFF(r->t_register);
 226         XFREE(MTYPE_NHRP_REGISTRATION, r);
 227 }
 228
 229 static struct nhrp_registration *
 230 nhrp_reg_by_nbma(struct nhrp_nhs *nhs, const union sockunion *nbma_addr)
 231 {
 232         struct nhrp_registration *r;
 233
 234         list_for_each_entry(
 235                 r, &nhs->reglist_head,
 236                 reglist_entry) if (sockunion_same(&r->peer->vc->remote.nbma,
 237                                                   nbma_addr)) return r;
 238         return NULL;
 239 }
 240
 241 static void nhrp_nhs_resolve_cb(struct resolver_query *q, int n,
 242                                 union sockunion *addrs)
 243 {
 244         struct nhrp_nhs *nhs = container_of(q, struct nhrp_nhs, dns_resolve);
 245         struct nhrp_interface *nifp = nhs->ifp->info;
 246         struct nhrp_registration *reg, *regn;
 247         int i;
 248
 249         nhs->t_resolve = NULL;
 250         if (n < 0) {
 251                 /* Failed, retry in a moment */
 252                 thread_add_timer(master, nhrp_nhs_resolve, nhs, 5,
 253                                  &nhs->t_resolve);
 254                 return;
 255         }
 256
 257         thread_add_timer(master, nhrp_nhs_resolve, nhs, 2 * 60 * 60,
 258                          &nhs->t_resolve);
 259
 260         list_for_each_entry(reg, &nhs->reglist_head, reglist_entry) reg->mark =
 261                 1;
 262
 263         nhs->hub = 0;
 264         for (i = 0; i < n; i++) {
 265                 if (sockunion_same(&addrs[i], &nifp->nbma)) {
 266                         nhs->hub = 1;
 267                         continue;
 268                 }
 269
 270                 reg = nhrp_reg_by_nbma(nhs, &addrs[i]);
 271                 if (reg) {
 272                         reg->mark = 0;
 273                         continue;
 274                 }
 275
 276                 reg = XCALLOC(MTYPE_NHRP_REGISTRATION, sizeof(*reg));
 277                 reg->peer = nhrp_peer_get(nhs->ifp, &addrs[i]);
 278                 reg->nhs = nhs;
 279                 reg->timeout = 1;
 280                 list_init(&reg->reglist_entry);
 281                 list_add_tail(&reg->reglist_entry, &nhs->reglist_head);
 282                 nhrp_peer_notify_add(reg->peer, &reg->peer_notifier,
 283                                      nhrp_reg_peer_notify);
 284                 thread_add_timer_msec(master, nhrp_reg_send_req, reg, 50,
 285                                       &reg->t_register);
 286         }
 287
 288         list_for_each_entry_safe(reg, regn, &nhs->reglist_head, reglist_entry)
 289         {
 290                 if (reg->mark)
 291                         nhrp_reg_delete(reg);
 292         }
 293 }
 294
 295 static int nhrp_nhs_resolve(struct thread *t)
 296 {
 297         struct nhrp_nhs *nhs = THREAD_ARG(t);
 298
 299         resolver_resolve(&nhs->dns_resolve, AF_INET, nhs->nbma_fqdn,
 300                          nhrp_nhs_resolve_cb);
 301
 302         return 0;
 303 }
 304
 305 int nhrp_nhs_add(struct interface *ifp, afi_t afi, union sockunion *proto_addr,
 306                  const char *nbma_fqdn)
 307 {
 308         struct nhrp_interface *nifp = ifp->info;
 309         struct nhrp_nhs *nhs;
 310
 311         if (sockunion_family(proto_addr) != AF_UNSPEC
 312             && sockunion_family(proto_addr) != afi2family(afi))
 313                 return NHRP_ERR_PROTOCOL_ADDRESS_MISMATCH;
 314
 315         list_for_each_entry(nhs, &nifp->afi[afi].nhslist_head, nhslist_entry)
 316         {
 317                 if (sockunion_family(&nhs->proto_addr) != AF_UNSPEC
 318                     && sockunion_family(proto_addr) != AF_UNSPEC
 319                     && sockunion_same(&nhs->proto_addr, proto_addr))
 320                         return NHRP_ERR_ENTRY_EXISTS;
 321
 322                 if (strcmp(nhs->nbma_fqdn, nbma_fqdn) == 0)
 323                         return NHRP_ERR_ENTRY_EXISTS;
 324         }
 325
 326         nhs = XMALLOC(MTYPE_NHRP_NHS, sizeof(struct nhrp_nhs));
 327
 328         *nhs = (struct nhrp_nhs){
 329                 .afi = afi,
 330                 .ifp = ifp,
 331                 .proto_addr = *proto_addr,
 332                 .nbma_fqdn = strdup(nbma_fqdn),
 333                 .reglist_head = LIST_INITIALIZER(nhs->reglist_head),
 334         };
 335         list_add_tail(&nhs->nhslist_entry, &nifp->afi[afi].nhslist_head);
 336         thread_add_timer_msec(master, nhrp_nhs_resolve, nhs, 1000,
 337                               &nhs->t_resolve);
 338
 339         return NHRP_OK;
 340 }
 341
 342 int nhrp_nhs_del(struct interface *ifp, afi_t afi, union sockunion *proto_addr,
 343                  const char *nbma_fqdn)
 344 {
 345         struct nhrp_interface *nifp = ifp->info;
 346         struct nhrp_nhs *nhs, *nnhs;
 347         int ret = NHRP_ERR_ENTRY_NOT_FOUND;
 348
 349         if (sockunion_family(proto_addr) != AF_UNSPEC
 350             && sockunion_family(proto_addr) != afi2family(afi))
 351                 return NHRP_ERR_PROTOCOL_ADDRESS_MISMATCH;
 352
 353         list_for_each_entry_safe(nhs, nnhs, &nifp->afi[afi].nhslist_head,
 354                                  nhslist_entry)
 355         {
 356                 if (!sockunion_same(&nhs->proto_addr, proto_addr))
 357                         continue;
 358                 if (strcmp(nhs->nbma_fqdn, nbma_fqdn) != 0)
 359                         continue;
 360
 361                 nhrp_nhs_free(nhs);
 362                 ret = NHRP_OK;
 363         }
 364
 365         return ret;
 366 }
 367
 368 int nhrp_nhs_free(struct nhrp_nhs *nhs)
 369 {
 370         struct nhrp_registration *r, *rn;
 371
 372         list_for_each_entry_safe(r, rn, &nhs->reglist_head, reglist_entry)
 373                 nhrp_reg_delete(r);
 374         THREAD_OFF(nhs->t_resolve);
 375         list_del(&nhs->nhslist_entry);
 376         free((void *)nhs->nbma_fqdn);
 377         XFREE(MTYPE_NHRP_NHS, nhs);
 378         return 0;
 379 }
 380
 381 void nhrp_nhs_terminate(void)
 382 {
 383         struct vrf *vrf = vrf_lookup_by_id(VRF_DEFAULT);
 384         struct interface *ifp;
 385         struct nhrp_interface *nifp;
 386         struct nhrp_nhs *nhs, *tmp;
 387         afi_t afi;
 388
 389         FOR_ALL_INTERFACES (vrf, ifp) {
 390                 nifp = ifp->info;
 391                 for (afi = 0; afi < AFI_MAX; afi++) {
 392                         list_for_each_entry_safe(
 393                                 nhs, tmp, &nifp->afi[afi].nhslist_head,
 394                                 nhslist_entry) nhrp_nhs_free(nhs);
 395                 }
 396         }
 397 }
 398
 399 void nhrp_nhs_foreach(struct interface *ifp, afi_t afi,
 400                       void (*cb)(struct nhrp_nhs *, struct nhrp_registration *,
 401                                  void *),
 402                       void *ctx)
 403 {
 404         struct nhrp_interface *nifp = ifp->info;
 405         struct nhrp_nhs *nhs;
 406         struct nhrp_registration *reg;
 407
 408         list_for_each_entry(nhs, &nifp->afi[afi].nhslist_head, nhslist_entry)
 409         {
 410                 if (!list_empty(&nhs->reglist_head)) {
 411                         list_for_each_entry(reg, &nhs->reglist_head,
 412                                             reglist_entry) cb(nhs, reg, ctx);
 413                 } else
 414                         cb(nhs, 0, ctx);
 415         }
 416 }