bird/proto/ospf/lsupd.c

/*
 *	BIRD -- OSPF
 *
 *	(c) 2000--2004 Ondrej Filip <feela@network.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "ospf.h"


struct ospf_lsupd_packet
{
  struct ospf_packet ospf_packet;
  u32 lsano;			/* Number of LSA's */
};


/* Beware of unaligned access */
void ospf_dump_lsahdr(struct proto *p, struct ospf_lsa_header *lsa_n)
{
  struct ospf_lsa_header lsa;
  ntohlsah(lsa_n, &lsa);

  log(L_TRACE "%s:     LSA      Type: %04x, Id: %R, Rt: %R, Age: %u, Seq: %08x, Sum: %04x",
      p->name, lsa.type, lsa.id, lsa.rt, lsa.age, lsa.sn, lsa.checksum);
}

void ospf_dump_common(struct proto *p, struct ospf_packet *op)
{
  log(L_TRACE "%s:     length   %d", p->name, ntohs(op->length));
  log(L_TRACE "%s:     router   %R", p->name, ntohl(op->routerid));
}

static void ospf_dump_lsupd(struct proto *p, struct ospf_lsupd_packet *pkt)
{
  struct ospf_packet *op = &pkt->ospf_packet;

  ASSERT(op->type == LSUPD_P);
  ospf_dump_common(p, op);

  /* We know that ntohs(op->length) >= sizeof(struct ospf_lsa_header) */
  u8 *pbuf= (u8 *) pkt;
  unsigned int offset = sizeof(struct ospf_lsupd_packet);
  unsigned int bound = ntohs(op->length) - sizeof(struct ospf_lsa_header);
  unsigned int i, j;

  j = ntohl(pkt->lsano);
  for (i = 0; i < j; i++)
    {
      if ((offset > bound) || ((offset % 4) != 0))
	{
	  log(L_TRACE "%s:     LSA      invalid", p->name);
	  return;
	}

      struct ospf_lsa_header *lsa = (void *) (pbuf + offset);
      ospf_dump_lsahdr(p, lsa);
      offset += ntohs(lsa->length);
    }
}


#ifdef OSPFv2

int
ospf_lsa_flooding_allowed(struct ospf_lsa_header *lsa, u32 domain, struct ospf_iface *ifa)
{
  if (lsa->type == LSA_T_EXT)
    {
      if (ifa->type == OSPF_IT_VLINK)
	return 0;
      if (ifa->oa->stub)
	return 0;
      return 1;
    }
  else
    return ifa->oa->areaid == domain;
}

#else /* OSPFv3 */

static int
unknown_lsa_type(struct ospf_lsa_header *lsa)
{
  switch (lsa->type)
    {
    case LSA_T_RT:
    case LSA_T_NET:
    case LSA_T_SUM_NET:
    case LSA_T_SUM_RT:
    case LSA_T_EXT:
    case LSA_T_LINK:
    case LSA_T_PREFIX:
      return 0;

    default:
      return 1;
    }
}

int
ospf_lsa_flooding_allowed(struct ospf_lsa_header *lsa, u32 domain, struct ospf_iface *ifa)
{    
  u32 scope = LSA_SCOPE(lsa);

  /* 4.5.2 (Case 2) */
  if (unknown_lsa_type(lsa) && !(lsa->type & LSA_UBIT))
    scope = LSA_SCOPE_LINK;

  switch (scope)
    {
    case LSA_SCOPE_LINK:
      return ifa->iface->index == domain;

    case LSA_SCOPE_AREA:
      return ifa->oa->areaid == domain;

    case LSA_SCOPE_AS:
      if (ifa->type == OSPF_IT_VLINK)
	return 0;
      if (ifa->oa->stub)
	return 0;
      return 1;

    default:
      log(L_ERR "LSA with invalid scope");
      return 0;
    }
}

#endif

/**
 * ospf_lsupd_flood - send received or generated lsa to the neighbors
 * @po: OSPF protocol
 * @n: neighbor than sent this lsa (or NULL if generated)
 * @hn: LSA header followed by lsa body in network endianity (may be NULL) 
 * @hh: LSA header in host endianity (must be filled)
 * @domain: domain of LSA (must be filled)
 * @rtl: add this LSA into retransmission list
 *
 *
 * return value - was the LSA flooded back?
 */

int
ospf_lsupd_flood(struct proto_ospf *po,
		 struct ospf_neighbor *n, struct ospf_lsa_header *hn,
		 struct ospf_lsa_header *hh, u32 domain, int rtl)
{
  struct ospf_iface *ifa;
  struct ospf_neighbor *nn;
  struct top_hash_entry *en;
  struct proto *p = &po->proto;
  int ret, retval = 0;

  /* pg 148 */
  WALK_LIST(ifa, po->iface_list)
  {
    if (ifa->stub)
      continue;

    if (! ospf_lsa_flooding_allowed(hh, domain, ifa))
      continue;

    DBG("Wanted to flood LSA: Type: %u, ID: %R, RT: %R, SN: 0x%x, Age %u\n",
	hh->type, hh->id, hh->rt, hh->sn, hh->age);

    ret = 0;
    WALK_LIST(nn, ifa->neigh_list)
    {
      /* 13.3 (1a) */
      if (nn->state < NEIGHBOR_EXCHANGE)
	continue;

      /* 13.3 (1b) */
      if (nn->state < NEIGHBOR_FULL)
      {
	if ((en = ospf_hash_find_header(nn->lsrqh, domain, hh)) != NULL)
	{
	  DBG("That LSA found in lsreq list for neigh %R\n", nn->rid);

	  switch (lsa_comp(hh, &en->lsa))
	  {
	  case CMP_OLDER:
	    continue;
	    break;
	  case CMP_SAME:
	    s_rem_node(SNODE en);
	    if (en->lsa_body != NULL)
	      mb_free(en->lsa_body);
	    en->lsa_body = NULL;
	    DBG("Removing from lsreq list for neigh %R\n", nn->rid);
	    ospf_hash_delete(nn->lsrqh, en);
	    if (EMPTY_SLIST(nn->lsrql))
	      ospf_neigh_sm(nn, INM_LOADDONE);
	    continue;
	    break;
	  case CMP_NEWER:
	    s_rem_node(SNODE en);
	    if (en->lsa_body != NULL)
	      mb_free(en->lsa_body);
	    en->lsa_body = NULL;
	    DBG("Removing from lsreq list for neigh %R\n", nn->rid);
	    ospf_hash_delete(nn->lsrqh, en);
	    if (EMPTY_SLIST(nn->lsrql))
	      ospf_neigh_sm(nn, INM_LOADDONE);
	    break;
	  default:
	    bug("Bug in lsa_comp?");
	  }
	}
      }

      /* 13.3 (1c) */
      if (nn == n)
	continue;

      /* 13.3 (1d) */
      if (rtl)
      {
	/* In OSPFv3, there should be check whether receiving router understand
	   that type of LSA (for LSA types with U-bit == 0). But as we does not support
	   any optional LSA types, this is not needed yet */

	if ((en = ospf_hash_find_header(nn->lsrth, domain, hh)) == NULL)
	{
	  en = ospf_hash_get_header(nn->lsrth, domain, hh);
	}
	else
	{
	  s_rem_node(SNODE en);
	}
	s_add_tail(&nn->lsrtl, SNODE en);
	memcpy(&en->lsa, hh, sizeof(struct ospf_lsa_header));
	DBG("Adding that LSA for flood to %I\n", nn->ip);
      }
      else
      {
	if ((en = ospf_hash_find_header(nn->lsrth, domain, hh)) != NULL)
	{
	  s_rem_node(SNODE en);
	  ospf_hash_delete(nn->lsrth, en);
	}
      }

      ret = 1;
    }

    if (ret == 0)
      continue;			/* pg 150 (2) */

    if (n && (n->ifa == ifa))
    {
      if ((n->rid == ifa->drid) || n->rid == ifa->bdrid)
	continue;		/* pg 150 (3) */
      if (ifa->state == OSPF_IS_BACKUP)
	continue;		/* pg 150 (4) */
      retval = 1;
    }

    {
      u16 len, age;
      struct ospf_lsupd_packet *pk;
      struct ospf_packet *op;
      struct ospf_lsa_header *lh;

      pk = ospf_tx_buffer(ifa);
      op = &pk->ospf_packet;

      ospf_pkt_fill_hdr(ifa, pk, LSUPD_P);
      pk->lsano = htonl(1);

      lh = (struct ospf_lsa_header *) (pk + 1);

      /* Copy LSA into the packet */
      if (hn)
      {
	memcpy(lh, hn, ntohs(hn->length));
      }
      else
      {
	u8 *help;
	struct top_hash_entry *en;

	htonlsah(hh, lh);
	help = (u8 *) (lh + 1);
	en = ospf_hash_find_header(po->gr, domain, hh);
	htonlsab(en->lsa_body, help, hh->length - sizeof(struct ospf_lsa_header));
      }

      len = sizeof(struct ospf_lsupd_packet) + ntohs(lh->length);

      age = ntohs(lh->age);
      age += ifa->inftransdelay;
      if (age > LSA_MAXAGE)
	age = LSA_MAXAGE;
      lh->age = htons(age);

      op->length = htons(len);

      OSPF_PACKET(ospf_dump_lsupd, pk, "LSUPD packet flooded via %s", ifa->iface->name);

      switch (ifa->type)
      {
      case OSPF_IT_NBMA:
	if ((ifa->state == OSPF_IS_BACKUP) || (ifa->state == OSPF_IS_DR))
	  ospf_send_to_agt(ifa, NEIGHBOR_EXCHANGE);
	else
	  ospf_send_to_bdr(ifa);
	break;

      case OSPF_IT_VLINK:
	ospf_send_to(ifa, ifa->vip);
	break;

      default:
	if ((ifa->state == OSPF_IS_BACKUP) || (ifa->state == OSPF_IS_DR) ||
	    (ifa->type == OSPF_IT_PTP))
	  ospf_send_to(ifa, AllSPFRouters);
	else
	  ospf_send_to(ifa, AllDRouters);
      }
    }
  }
  return retval;
}

void				/* I send all I received in LSREQ */
ospf_lsupd_send_list(struct ospf_neighbor *n, list * l)
{
  struct ospf_area *oa = n->ifa->oa;
  struct proto *p = &oa->po->proto;
  struct l_lsr_head *lsr;
  struct top_hash_entry *en;
  struct ospf_lsupd_packet *pkt;
  u32 len, len2, lsano;
  char *buf;

  pkt = ospf_tx_buffer(n->ifa);
  buf = (void *) pkt;

  lsr = HEAD(*l);
  while(NODE_NEXT(lsr))
  {
    /* Prepare the packet */
    ospf_pkt_fill_hdr(n->ifa, pkt, LSUPD_P);
    len = sizeof(struct ospf_lsupd_packet);
    lsano = 0;

    /* Fill the packet with LSAs */
    while(NODE_NEXT(lsr))
    {
      u32 domain = ospf_lsa_domain(lsr->lsh.type, n->ifa);
      en = ospf_hash_find(oa->po->gr, domain, lsr->lsh.id, lsr->lsh.rt, lsr->lsh.type);
      if (en == NULL)
      {
	/* Probably flushed LSA, this should not happen */
	log(L_WARN "OSPF: LSA disappeared (Type: %04x, Id: %R, Rt: %R)", 
	    lsr->lsh.type, lsr->lsh.id, lsr->lsh.rt);
	lsr = NODE_NEXT(lsr);
	continue;			
      }

      len2 = len + en->lsa.length;
      if (len2 > ospf_pkt_maxsize(n->ifa))
      {
	/* The packet if full, stop adding LSAs and sent it */
	if (lsano > 0)
	  break;

	/* LSA is larger than MTU, check buffer size */
	if (len2 > ospf_pkt_bufsize(n->ifa))
	{
	  /* Cannot fit in a tx buffer, skip that */
	  log(L_WARN "OSPF: LSA too large to send (Type: %04x, Id: %R, Rt: %R)", 
	      lsr->lsh.type, lsr->lsh.id, lsr->lsh.rt);
	  lsr = NODE_NEXT(lsr);
	  continue;
	}
      }

      /* Copy the LSA to the packet */
      htonlsah(&(en->lsa), (struct ospf_lsa_header *) (buf + len));
      htonlsab(en->lsa_body, buf + len + sizeof(struct ospf_lsa_header),
	       en->lsa.length - sizeof(struct ospf_lsa_header));
      len = len2;
      lsano++;
      lsr = NODE_NEXT(lsr);
    }

    if (lsano == 0)
      break;

    /* Send the packet */
    pkt->lsano = htonl(lsano);
    pkt->ospf_packet.length = htons(len);
    OSPF_PACKET(ospf_dump_lsupd, pkt, "LSUPD packet sent to %I via %s",
		n->ip, n->ifa->iface->name);
    ospf_send_to(n->ifa, n->ip);
  }
}

void
ospf_lsupd_receive(struct ospf_packet *ps_i, struct ospf_iface *ifa,
		   struct ospf_neighbor *n)
{

  struct ospf_neighbor *ntmp;
  struct proto_ospf *po = ifa->oa->po;
  struct proto *p = &po->proto;
  unsigned int i, max, sendreq = 1;

  unsigned int size = ntohs(ps_i->length);
  if (size < (sizeof(struct ospf_lsupd_packet) + sizeof(struct ospf_lsa_header)))
  {
    log(L_ERR "OSPF: Bad LSUPD packet from %I - too short (%u B)", n->ip, size);
    return;
  }

  struct ospf_lsupd_packet *ps = (void *) ps_i;
  OSPF_PACKET(ospf_dump_lsupd, ps, "LSUPD packet received from %I via %s", n->ip, ifa->iface->name);

  if (n->state < NEIGHBOR_EXCHANGE)
  {
    OSPF_TRACE(D_PACKETS, "Received lsupd in lesser state than EXCHANGE from (%I)", n->ip);
    return;
  }

  ospf_neigh_sm(n, INM_HELLOREC);	/* Questionable */

  unsigned int offset = sizeof(struct ospf_lsupd_packet);
  unsigned int bound = size - sizeof(struct ospf_lsa_header);

  max = ntohl(ps->lsano);
  for (i = 0; i < max; i++)
  {
    struct ospf_lsa_header lsatmp;
    struct top_hash_entry *lsadb;

    if (offset > bound)
    {
      log(L_WARN "Received lsupd from %I is too short!", n->ip);
      ospf_neigh_sm(n, INM_BADLSREQ);
      return;
    }

    struct ospf_lsa_header *lsa = (void *) (((u8 *) ps) + offset);
    unsigned int lsalen = ntohs(lsa->length);
    offset += lsalen;
 
    if ((offset > size) || ((lsalen % 4) != 0) ||
	(lsalen <= sizeof(struct ospf_lsa_header)))
    {
      log(L_WARN "Received LSA from %I with bad length", n->ip);
      ospf_neigh_sm(n, INM_BADLSREQ);
      break;
    }

    /* pg 143 (1) */
    u16 chsum = lsa->checksum;
    if (chsum != lsasum_check(lsa, NULL))
    {
      log(L_WARN "Received bad lsa checksum from %I: %x %x", n->ip, chsum, lsa->checksum);
      continue;
    }

#ifdef OSPFv2
    /* pg 143 (2) */
    if ((lsa->type < LSA_T_RT) || (lsa->type > LSA_T_EXT))
    {
      log(L_WARN "Unknown LSA type from %I", n->ip);
      continue;
    }

    /* pg 143 (3) */
    if ((lsa->type == LSA_T_EXT) && ifa->oa->stub)
    {
      log(L_WARN "Received External LSA in stub area from %I", n->ip);
      continue;
    }
#else /* OSPFv3 */
    /* 4.5.1 (2) */
    if ((LSA_SCOPE(lsa) == LSA_SCOPE_AS) && ifa->oa->stub)
    {
      log(L_WARN "Received LSA with AS scope in stub area from %I", n->ip);
      continue;
    }

    /* 4.5.1 (3) */
    if ((LSA_SCOPE(lsa) == LSA_SCOPE_RES))
    {
      log(L_WARN "Received LSA with invalid scope from %I", n->ip);
      continue;
    }
#endif

    ntohlsah(lsa, &lsatmp);

    DBG("Update Type: %u ID: %R RT: %R, Sn: 0x%08x Age: %u, Sum: %u\n",
	lsatmp.type, lsatmp.id, lsatmp.rt, lsatmp.sn, lsatmp.age, lsatmp.checksum);

    /* FIXME domain should be link id for unknown LSA types with zero Ubit */
    u32 domain = ospf_lsa_domain(lsatmp.type, ifa);
    lsadb = ospf_hash_find_header(po->gr, domain, &lsatmp);

#ifdef LOCAL_DEBUG
    if (lsadb)
      DBG("I have Type: %u ID: %R RT: %R, Sn: 0x%08x Age: %u, Sum: %u\n",
	  lsadb->lsa.type, lsadb->lsa.id, lsadb->lsa.rt,
	  lsadb->lsa.sn, lsadb->lsa.age, lsadb->lsa.checksum);
#endif

    /* pg 143 (4) */
    if ((lsatmp.age == LSA_MAXAGE) && (lsadb == NULL) && can_flush_lsa(po))
    {
      ospf_lsack_enqueue(n, lsa, ACKL_DIRECT);
      continue;
    }

    /* pg 144 (5) */
    if ((lsadb == NULL) || (lsa_comp(&lsatmp, &lsadb->lsa) == CMP_NEWER))
    {
      struct ospf_iface *ift = NULL;
      int self = (lsatmp.rt == po->router_id);

      DBG("PG143(5): Received LSA is newer\n");

#ifdef OSPFv2
      /* 13.4 - check self-originated LSAs of NET type */
      if ((!self) && (lsatmp.type == LSA_T_NET))
      {
	struct ospf_iface *nifa;
	WALK_LIST(nifa, po->iface_list)
	{
	  if (!nifa->iface)
	    continue;
	  if (ipa_equal(nifa->addr->ip, ipa_from_u32(lsatmp.id)))
	  {
	    self = 1;
	    break;
	  }
	}
      }
#endif

      /* pg 145 (5f) - premature aging of self originated lsa */
      if (self)
      {
	if ((lsatmp.age == LSA_MAXAGE) && (lsatmp.sn == LSA_MAXSEQNO))
	{
	  ospf_lsack_enqueue(n, lsa, ACKL_DIRECT);
	  continue;
	}

	OSPF_TRACE(D_EVENTS, "Received old self-originated LSA (Type: %04x, Id: %R, Rt: %R)",
		   lsatmp.type, lsatmp.id, lsatmp.rt);

	if (lsadb)
	{
	  OSPF_TRACE(D_EVENTS, "Reflooding new self-originated LSA with newer sequence number");
	  lsadb->lsa.sn = lsatmp.sn + 1;
	  lsadb->lsa.age = 0;
	  lsadb->inst_t = now;
	  lsadb->ini_age = 0;
	  lsasum_calculate(&lsadb->lsa, lsadb->lsa_body);
	  ospf_lsupd_flood(po, NULL, NULL, &lsadb->lsa, domain, 1);
	}
	else
	{
	  OSPF_TRACE(D_EVENTS, "Premature aging it");
	  lsatmp.age = LSA_MAXAGE;
	  lsatmp.sn = LSA_MAXSEQNO;
	  lsa->age = htons(LSA_MAXAGE);
	  lsa->sn = htonl(LSA_MAXSEQNO);
	  lsasum_check(lsa, (lsa + 1));	/* It also calculates chsum! */
	  lsatmp.checksum = ntohs(lsa->checksum);
	  ospf_lsupd_flood(po, NULL, lsa, &lsatmp, domain, 0);
	}
	continue;
      }

      /* pg 144 (5a) */
      if (lsadb && ((now - lsadb->inst_t) <= MINLSARRIVAL))	/* FIXME: test for flooding? */
      {
	OSPF_TRACE(D_EVENTS, "Skipping LSA received in less that MINLSARRIVAL");
	sendreq = 0;
	continue;
      }

      /* Remove old from all ret lists */
      /* pg 144 (5c) */
      /* Must be done before (5b), otherwise it also removes the new entries from (5b) */
      if (lsadb)
	WALK_LIST(ift, po->iface_list)
	  WALK_LIST(ntmp, ift->neigh_list)
      {
	struct top_hash_entry *en;
	if (ntmp->state > NEIGHBOR_EXSTART)
	  if ((en = ospf_hash_find_header(ntmp->lsrth, domain, &lsadb->lsa)) != NULL)
	  {
	    s_rem_node(SNODE en);
	    ospf_hash_delete(ntmp->lsrth, en);
	  }
      }

      /* pg 144 (5b) */
      if (ospf_lsupd_flood(po, n, lsa, &lsatmp, domain, 1) == 0)
      {
	DBG("Wasn't flooded back\n");	/* ps 144(5e), pg 153 */
	if (ifa->state == OSPF_IS_BACKUP)
	{
	  if (ifa->drid == n->rid)
	    ospf_lsack_enqueue(n, lsa, ACKL_DELAY);
	}
	else
	  ospf_lsack_enqueue(n, lsa, ACKL_DELAY);
      }

      if ((lsatmp.age == LSA_MAXAGE) && (lsatmp.sn == LSA_MAXSEQNO)
	  && lsadb && can_flush_lsa(po))
      {
	flush_lsa(lsadb, po);
	schedule_rtcalc(po);
	continue;
      }				/* FIXME lsack? */

      /* pg 144 (5d) */
      void *body = mb_alloc(p->pool, lsatmp.length - sizeof(struct ospf_lsa_header));
      ntohlsab(lsa + 1, body, lsatmp.length - sizeof(struct ospf_lsa_header));

      /* We will do validation check after flooding and
	 acknowledging given LSA to minimize problems
	 when communicating with non-validating peer */
      if (lsa_validate(&lsatmp, body) == 0)
      {
	log(L_WARN "Received invalid LSA from %I", n->ip);
	mb_free(body);
	continue;	
      }

      lsadb = lsa_install_new(po, &lsatmp, domain, body);
      DBG("New LSA installed in DB\n");

#ifdef OSPFv3
      /* Events 6,7 from RFC5340 4.4.3. */
      if ((lsatmp.type == LSA_T_LINK) &&
	  (ifa->state == OSPF_IS_DR))
	schedule_net_lsa(ifa);
#endif

      continue;
    }

    /* FIXME pg145 (6) */

    /* pg145 (7) */
    if (lsa_comp(&lsatmp, &lsadb->lsa) == CMP_SAME)
    {
      struct top_hash_entry *en;
      DBG("PG145(7) Got the same LSA\n");
      if ((en = ospf_hash_find_header(n->lsrth, lsadb->domain, &lsadb->lsa)) != NULL)
      {
	/* pg145 (7a) */
	s_rem_node(SNODE en);
	ospf_hash_delete(n->lsrth, en);

	if (ifa->state == OSPF_IS_BACKUP)
	{
	  if (n->rid == ifa->drid)
	    ospf_lsack_enqueue(n, lsa, ACKL_DELAY);
	}
      }
      else
      {
	/* pg145 (7b) */
	ospf_lsack_enqueue(n, lsa, ACKL_DIRECT);
      }
      sendreq = 0;
      continue;
    }

    /* pg145 (8) */
    if ((lsadb->lsa.age == LSA_MAXAGE) && (lsadb->lsa.sn == LSA_MAXSEQNO))
    {
      continue;
    }

    {
      list l;
      struct l_lsr_head ll;
      init_list(&l);
      ll.lsh.id = lsadb->lsa.id;
      ll.lsh.rt = lsadb->lsa.rt;
      ll.lsh.type = lsadb->lsa.type;
      add_tail(&l, NODE & ll);
      ospf_lsupd_send_list(n, &l);
    }
  }

  /* Send direct LSAs */
  ospf_lsack_send(n, ACKL_DIRECT);

  if (sendreq && (n->state == NEIGHBOR_LOADING))
  {
    ospf_lsreq_send(n);		/* Ask for another part of neighbor's database */
  }
}

void
ospf_lsupd_flush_nlsa(struct proto_ospf *po, struct top_hash_entry *en)
{
  struct ospf_lsa_header *lsa = &en->lsa;
  struct proto *p = &po->proto;

  lsa->age = LSA_MAXAGE;
  lsa->sn = LSA_MAXSEQNO;
  lsasum_calculate(lsa, en->lsa_body);
  OSPF_TRACE(D_EVENTS, "Premature aging self originated lsa!");
  OSPF_TRACE(D_EVENTS, "Type: %04x, Id: %R, Rt: %R", lsa->type, lsa->id, lsa->rt);
  ospf_lsupd_flood(po, NULL, NULL, lsa, en->domain, 0);
}