proto/ospf/hello.c

   1 /*
   2  *      BIRD -- OSPF
   3  *
   4  *      (c) 1999--2004 Ondrej Filip <feela@network.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 #include "ospf.h"
  10
  11
  12 #ifdef OSPFv2
  13 struct ospf_hello_packet
  14 {
  15   struct ospf_packet ospf_packet;
  16   ip_addr netmask;
  17   u16 helloint;
  18   u8 options;
  19   u8 priority;
  20   u32 deadint;
  21   u32 dr;
  22   u32 bdr;
  23 };
  24 #endif
  25
  26
  27 #ifdef OSPFv3
  28 struct ospf_hello_packet
  29 {
  30   struct ospf_packet ospf_packet;
  31   u32 iface_id;
  32   u8 priority;
  33   u8 options3;
  34   u8 options2;
  35   u8 options;
  36   u16 helloint;
  37   u16 deadint;
  38   u32 dr;
  39   u32 bdr;
  40 };
  41 #endif
  42
  43
  44 void
  45 ospf_hello_receive(struct ospf_packet *ps_i, struct ospf_iface *ifa,
  46                    struct ospf_neighbor *n, ip_addr faddr)
  47 {
  48   struct proto_ospf *po = ifa->oa->po;
  49   struct proto *p = &po->proto;
  50   char *beg = "OSPF: Bad HELLO packet from ";
  51   unsigned int size, i, twoway, eligible, peers;
  52   u32 tmp;
  53   u32 *pnrid;
  54
  55   size = ntohs(ps_i->length);
  56   if (size < sizeof(struct ospf_hello_packet))
  57   {
  58     log(L_ERR "%s%I - too short (%u B)", beg, faddr, size);
  59     return;
  60   }
  61
  62   struct ospf_hello_packet *ps = (void *) ps_i;
  63
  64   OSPF_TRACE(D_PACKETS, "HELLO packet received from %I via %s%s", faddr,
  65       (ifa->type == OSPF_IT_VLINK ? "vlink-" : ""), ifa->iface->name);
  66
  67 #ifdef OSPFv2
  68   ip_addr mask = ps->netmask;
  69   ipa_ntoh(mask);
  70   if ((ifa->type != OSPF_IT_VLINK) &&
  71       (ifa->type != OSPF_IT_PTP) &&
  72       !ipa_equal(mask, ipa_mkmask(ifa->addr->pxlen)))
  73   {
  74     log(L_ERR "%s%I - netmask mismatch (%I)", beg, faddr, mask);
  75     return;
  76   }
  77 #endif
  78
  79   tmp = ntohs(ps->helloint);
  80   if (tmp != ifa->helloint)
  81   {
  82     log(L_ERR "%s%I - hello interval mismatch (%d)", beg, faddr, tmp);
  83     return;
  84   }
  85
  86 #ifdef OSPFv2
  87   tmp = ntohl(ps->deadint);
  88 #else /* OSPFv3 */
  89   tmp = ntohs(ps->deadint);
  90 #endif
  91   if (tmp != ifa->dead)
  92   {
  93     log(L_ERR "%s%I - dead interval mismatch (%d)", beg, faddr, tmp);
  94     return;
  95   }
  96
  97   tmp = !(ps->options & OPT_E);
  98   if (tmp != !!ifa->oa->stub)
  99   {
 100     log(L_ERR "%s%I - stub area flag mismatch (%d)", beg, faddr, tmp);
 101     return;
 102   }
 103
 104   if (!n)
 105   {
 106     if ((ifa->type == OSPF_IT_NBMA))
 107     {
 108       struct nbma_node *nn;
 109       int found = 0;
 110
 111       WALK_LIST(nn, ifa->nbma_list)
 112       {
 113         if (ipa_equal(faddr, nn->ip))
 114         {
 115           found = 1;
 116           break;
 117         }
 118       }
 119       if ((found == 0) && (ifa->strictnbma))
 120       {
 121         log(L_WARN "Ignoring new neighbor: %I on %s", faddr,
 122             ifa->iface->name);
 123         return;
 124       }
 125       if (found)
 126       {
 127         eligible = nn->eligible;
 128         if (((ps->priority == 0) && eligible)
 129             || ((ps->priority > 0) && (eligible == 0)))
 130         {
 131           log(L_ERR "Eligibility mismatch for neighbor: %I on %s",
 132               faddr, ifa->iface->name);
 133           return;
 134         }
 135       }
 136     }
 137     OSPF_TRACE(D_EVENTS, "New neighbor found: %I on %s", faddr,
 138                ifa->iface->name);
 139
 140     n = ospf_neighbor_new(ifa);
 141
 142     n->rid = ntohl(((struct ospf_packet *) ps)->routerid);
 143     n->ip = faddr;
 144     n->dr = ntohl(ps->dr);
 145     n->bdr = ntohl(ps->bdr);
 146     n->priority = ps->priority;
 147 #ifdef OSPFv3
 148     n->iface_id = ntohl(ps->iface_id);
 149 #endif
 150   }
 151   ospf_neigh_sm(n, INM_HELLOREC);
 152
 153   pnrid = (u32 *) ((struct ospf_hello_packet *) (ps + 1));
 154
 155   peers = (size - sizeof(struct ospf_hello_packet))/ sizeof(u32);
 156
 157   twoway = 0;
 158   for (i = 0; i < peers; i++)
 159   {
 160     if (ntohl(pnrid[i]) == po->router_id)
 161     {
 162       DBG("%s: Twoway received from %I\n", p->name, faddr);
 163       ospf_neigh_sm(n, INM_2WAYREC);
 164       twoway = 1;
 165       break;
 166     }
 167   }
 168
 169   if (!twoway)
 170     ospf_neigh_sm(n, INM_1WAYREC);
 171
 172   u32 olddr = n->dr;
 173   u32 oldbdr = n->bdr;
 174   u32 oldpriority = n->priority;
 175 #ifdef OSPFv3
 176   u32 oldiface_id = n->iface_id;
 177 #endif
 178
 179   n->dr = ntohl(ps->dr);
 180   n->bdr = ntohl(ps->bdr);
 181   n->priority = ps->priority;
 182 #ifdef OSPFv3
 183   n->iface_id = ntohl(ps->iface_id);
 184 #endif
 185
 186
 187   /* Check priority change */
 188   if (n->state >= NEIGHBOR_2WAY)
 189   {
 190 #ifdef OSPFv2
 191     u32 neigh = ipa_to_u32(n->ip);
 192 #else /* OSPFv3 */
 193     u32 neigh = n->rid;
 194 #endif
 195
 196     if (n->priority != oldpriority)
 197       ospf_iface_sm(ifa, ISM_NEICH);
 198
 199 #ifdef OSPFv3
 200     if (n->iface_id != oldiface_id)
 201       ospf_iface_sm(ifa, ISM_NEICH);
 202 #endif
 203
 204     /* Neighbor is declaring itself ad DR and there is no BDR */
 205     if ((n->dr == neigh) && (n->bdr == 0)
 206         && (n->state != NEIGHBOR_FULL))
 207       ospf_iface_sm(ifa, ISM_BACKS);
 208
 209     /* Neighbor is declaring itself as BDR */
 210     if ((n->bdr == neigh) && (n->state != NEIGHBOR_FULL))
 211       ospf_iface_sm(ifa, ISM_BACKS);
 212
 213     /* Neighbor is newly declaring itself as DR or BDR */
 214     if (((n->dr == neigh) && (n->dr != olddr))
 215         || ((n->bdr == neigh) && (n->bdr != oldbdr)))
 216       ospf_iface_sm(ifa, ISM_NEICH);
 217
 218     /* Neighbor is no more declaring itself as DR or BDR */
 219     if (((olddr == neigh) && (n->dr != olddr))
 220         || ((oldbdr == neigh) && (n->bdr != oldbdr)))
 221       ospf_iface_sm(ifa, ISM_NEICH);
 222   }
 223
 224   if (ifa->type == OSPF_IT_NBMA)
 225   {
 226     if ((ifa->priority == 0) && (n->priority > 0))
 227       ospf_hello_send(NULL, 0, n);
 228   }
 229   ospf_neigh_sm(n, INM_HELLOREC);
 230 }
 231
 232 void
 233 ospf_hello_send(timer *timer, int poll, struct ospf_neighbor *dirn)
 234 {
 235   struct ospf_iface *ifa;
 236   struct ospf_hello_packet *pkt;
 237   struct ospf_packet *op;
 238   struct proto *p;
 239   struct ospf_neighbor *neigh, *n1;
 240   u16 length;
 241   u32 *pp;
 242   int i, send;
 243   struct nbma_node *nb;
 244
 245   if (timer == NULL)
 246     ifa = dirn->ifa;
 247   else
 248     ifa = (struct ospf_iface *) timer->data;
 249
 250   if (ifa->state == OSPF_IS_DOWN)
 251     return;
 252
 253   if (ifa->stub)
 254     return;                     /* Don't send any packet on stub iface */
 255
 256   p = (struct proto *) (ifa->oa->po);
 257   DBG("%s: Hello/Poll timer fired on interface %s with IP %I\n",
 258       p->name, ifa->iface->name, ifa->addr->ip);
 259
 260   /* Now we should send a hello packet */
 261   pkt = ospf_tx_buffer(ifa);
 262   op = &pkt->ospf_packet;
 263
 264   /* Now fill ospf_hello header */
 265   ospf_pkt_fill_hdr(ifa, pkt, HELLO_P);
 266
 267 #ifdef OSPFv2
 268   pkt->netmask = ipa_mkmask(ifa->addr->pxlen);
 269   ipa_hton(pkt->netmask);
 270   if ((ifa->type == OSPF_IT_VLINK) || (ifa->type == OSPF_IT_PTP))
 271     pkt->netmask = IPA_NONE;
 272 #endif
 273
 274   pkt->helloint = ntohs(ifa->helloint);
 275   pkt->priority = ifa->priority;
 276
 277 #ifdef OSPFv3
 278   pkt->iface_id = htonl(ifa->iface->index);
 279
 280   pkt->options3 = ifa->oa->options >> 16;
 281   pkt->options2 = ifa->oa->options >> 8;
 282 #endif
 283   pkt->options = ifa->oa->options;
 284
 285 #ifdef OSPFv2
 286   pkt->deadint = htonl(ifa->dead);
 287   pkt->dr = htonl(ipa_to_u32(ifa->drip));
 288   pkt->bdr = htonl(ipa_to_u32(ifa->bdrip));
 289 #else /* OSPFv3 */
 290   pkt->deadint = htons(ifa->dead);
 291   pkt->dr = htonl(ifa->drid);
 292   pkt->bdr = htonl(ifa->bdrid);
 293 #endif
 294
 295   /* Fill all neighbors */
 296   i = 0;
 297   pp = (u32 *) (((u8 *) pkt) + sizeof(struct ospf_hello_packet));
 298   WALK_LIST(neigh, ifa->neigh_list)
 299   {
 300     if ((i+1) * sizeof(u32) + sizeof(struct ospf_hello_packet) > ospf_pkt_maxsize(ifa))
 301     {
 302       OSPF_TRACE(D_PACKETS, "Too many neighbors on the interface!");
 303       break;
 304     }
 305     *(pp + i) = htonl(neigh->rid);
 306     i++;
 307   }
 308
 309   length = sizeof(struct ospf_hello_packet) + i * sizeof(u32);
 310   op->length = htons(length);
 311
 312   switch(ifa->type)
 313   {
 314     case OSPF_IT_NBMA:
 315       if (timer == NULL)                /* Response to received hello */
 316       {
 317         ospf_send_to(ifa, dirn->ip);
 318       }
 319       else
 320       {
 321         int toall = 0;
 322         int meeli = 0;
 323         if (ifa->state > OSPF_IS_DROTHER)
 324           toall = 1;
 325         if (ifa->priority > 0)
 326           meeli = 1;
 327
 328         WALK_LIST(nb, ifa->nbma_list)
 329         {
 330           send = 1;
 331           WALK_LIST(n1, ifa->neigh_list)
 332           {
 333             if (ipa_equal(nb->ip, n1->ip))
 334             {
 335               send = 0;
 336               break;
 337             }
 338           }
 339           if ((poll == 1) && (send))
 340           {
 341             if (toall || (meeli && nb->eligible))
 342               ospf_send_to(ifa, nb->ip);
 343           }
 344         }
 345         if (poll == 0)
 346         {
 347           WALK_LIST(n1, ifa->neigh_list)
 348           {
 349             if (toall || (n1->rid == ifa->drid) || (n1->rid == ifa->bdrid) ||
 350                 (meeli && (n1->priority > 0)))
 351               ospf_send_to(ifa, n1->ip);
 352           }
 353         }
 354       }
 355       break;
 356     case OSPF_IT_VLINK:
 357       ospf_send_to(ifa, ifa->vip);
 358       break;
 359     default:
 360       ospf_send_to(ifa, AllSPFRouters);
 361   }
 362
 363   OSPF_TRACE(D_PACKETS, "HELLO packet sent via %s%s",
 364              (ifa->type == OSPF_IT_VLINK ? "vlink-" : ""), ifa->iface->name);
 365 }