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