ospf_packet.c

router source code for the ospdf.

  if (listcount (oi->ls_ack) > 0)
    ospf_ls_ack_send_delayed (oi);

  /* Set LS Ack timer. */
  OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);

  return 0;
}

int
ospf_write (struct thread *thread)
{
  struct ospf *ospf = THREAD_ARG (thread);
  struct ospf_interface *oi;
  struct ospf_packet *op;
  struct sockaddr_in sa_dst;
  struct ip iph;
  struct msghdr msg;
  struct iovec iov[2];
  u_char type;
  int ret;
  int flags = 0;
  listnode node;
  
  ospf->t_write = NULL;

  node = listhead (ospf->oi_write_q);
  assert (node);
  oi = getdata (node);
  assert (oi);
  
  /* Get one packet from queue. */
  op = ospf_fifo_head (oi->obuf);
  assert (op);
  assert (op->length >= OSPF_HEADER_SIZE);

  if (op->dst.s_addr == htonl (OSPF_ALLSPFROUTERS)
      || op->dst.s_addr == htonl (OSPF_ALLDROUTERS))
    ospf_if_ipmulticast (ospf, oi->address, oi->ifp->ifindex);

  /* Rewrite the md5 signature & update the seq */
  ospf_make_md5_digest (oi, op);

  memset (&sa_dst, 0, sizeof (sa_dst));
  sa_dst.sin_family = AF_INET;
#ifdef HAVE_SIN_LEN
  sa_dst.sin_len = sizeof(sa_dst);
#endif /* HAVE_SIN_LEN */
  sa_dst.sin_addr = op->dst;
  sa_dst.sin_port = htons (0);

  /* Set DONTROUTE flag if dst is unicast. */
  if (oi->type != OSPF_IFTYPE_VIRTUALLINK)
    if (!IN_MULTICAST (htonl (op->dst.s_addr)))
      flags = MSG_DONTROUTE;

  iph.ip_hl = sizeof (struct ip) >> 2;
  iph.ip_v = IPVERSION;
  iph.ip_tos = IPTOS_PREC_INTERNETCONTROL;
#if defined(__NetBSD__) || defined(__FreeBSD__)
  iph.ip_len = iph.ip_hl*4 + op->length;
#else
  iph.ip_len = htons (iph.ip_hl*4 + op->length);
#endif
  iph.ip_id = 0;
  iph.ip_off = 0;
  if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
    iph.ip_ttl = OSPF_VL_IP_TTL;
  else
    iph.ip_ttl = OSPF_IP_TTL;
  iph.ip_p = IPPROTO_OSPFIGP;
  iph.ip_sum = 0;
  iph.ip_src.s_addr = oi->address->u.prefix4.s_addr;
  iph.ip_dst.s_addr = op->dst.s_addr;

  memset (&msg, 0, sizeof (msg));
  msg.msg_name = &sa_dst;
  msg.msg_namelen = sizeof (sa_dst); 
  msg.msg_iov = iov;
  msg.msg_iovlen = 2;
  iov[0].iov_base = (char*)&iph;
  iov[0].iov_len = iph.ip_hl*4;
  iov[1].iov_base = STREAM_DATA (op->s);
  iov[1].iov_len = op->length;

  ret = sendmsg (ospf->fd, &msg, flags);
  
  if (ret < 0)
    zlog_warn ("*** sendmsg in ospf_write failed with %s", strerror (errno));

  /* Retrieve OSPF packet type. */
  stream_set_getp (op->s, 1);
  type = stream_getc (op->s);

  /* Show debug sending packet. */
  if (IS_DEBUG_OSPF_PACKET (type - 1, SEND))
    {
      if (IS_DEBUG_OSPF_PACKET (type - 1, DETAIL))
	{
	  zlog_info ("-----------------------------------------------------");
	  stream_set_getp (op->s, 0);
	  ospf_packet_dump (op->s);
	}

      zlog_info ("%s sent to [%s] via [%s].",
		 ospf_packet_type_str[type], inet_ntoa (op->dst),
		 IF_NAME (oi));

      if (IS_DEBUG_OSPF_PACKET (type - 1, DETAIL))
	zlog_info ("-----------------------------------------------------");
    }

  /* Now delete packet from queue. */
  ospf_packet_delete (oi);

  if (ospf_fifo_head (oi->obuf) == NULL)
    {
      oi->on_write_q = 0;
      list_delete_node (ospf->oi_write_q, node);
    }
  
  /* If packets still remain in queue, call write thread. */
  if (!list_isempty (ospf->oi_write_q))
    ospf->t_write =                                              
      thread_add_write (master, ospf_write, ospf, ospf->fd);

  return 0;
}

/* OSPF Hello message read -- RFC2328 Section 10.5. */
void
ospf_hello (struct ip *iph, struct ospf_header *ospfh,
	    struct stream * s, struct ospf_interface *oi, int size)
{
  struct ospf_hello *hello;
  struct ospf_neighbor *nbr;
  struct route_node *rn;
  struct prefix p, key;
  int old_state;

  /* increment statistics. */
  oi->hello_in++;

  hello = (struct ospf_hello *) STREAM_PNT (s);

  /* If Hello is myself, silently discard. */
  if (IPV4_ADDR_SAME (&ospfh->router_id, &oi->ospf->router_id))
    return;

  /* If incoming interface is passive one, ignore Hello. */
  if (OSPF_IF_PARAM (oi, passive_interface) == OSPF_IF_PASSIVE)
    return;

  /* get neighbor prefix. */
  p.family = AF_INET;
  p.prefixlen = ip_masklen (hello->network_mask);
  p.u.prefix4 = iph->ip_src;

  /* Compare network mask. */
  /* Checking is ignored for Point-to-Point and Virtual link. */
  if (oi->type != OSPF_IFTYPE_POINTOPOINT 
      && oi->type != OSPF_IFTYPE_VIRTUALLINK)
    if (oi->address->prefixlen != p.prefixlen)
      {
	zlog_warn ("Packet %s [Hello:RECV]: NetworkMask mismatch.",
		   inet_ntoa (ospfh->router_id));
	return;
      }

  /* Compare Hello Interval. */
  if (OSPF_IF_PARAM (oi, v_hello) != ntohs (hello->hello_interval))
    {
      zlog_warn ("Packet %s [Hello:RECV]: HelloInterval mismatch.",
		 inet_ntoa (ospfh->router_id));
      return;
    }

  /* Compare Router Dead Interval. */
  if (OSPF_IF_PARAM (oi, v_wait) != ntohl (hello->dead_interval))
    {
      zlog_warn ("Packet %s [Hello:RECV]: RouterDeadInterval mismatch.",
		 inet_ntoa (ospfh->router_id));
      return;
    }

  if (IS_DEBUG_OSPF_EVENT)
    zlog_info ("Packet %s [Hello:RECV]: Options %s",
	       inet_ntoa (ospfh->router_id),
	       ospf_options_dump (hello->options));

  /* Compare options. */
#define REJECT_IF_TBIT_ON	1 /* XXX */
#ifdef REJECT_IF_TBIT_ON
  if (CHECK_FLAG (hello->options, OSPF_OPTION_T))
    {
      /*
       * This router does not support non-zero TOS.
       * Drop this Hello packet not to establish neighbor relationship.
       */
      zlog_warn ("Packet %s [Hello:RECV]: T-bit on, drop it.",
		 inet_ntoa (ospfh->router_id));
      return;
    }
#endif /* REJECT_IF_TBIT_ON */

#ifdef HAVE_OPAQUE_LSA
  if (CHECK_FLAG (oi->ospf->config, OSPF_OPAQUE_CAPABLE)
      && CHECK_FLAG (hello->options, OSPF_OPTION_O))
    {
      /*
       * This router does know the correct usage of O-bit
       * the bit should be set in DD packet only.
       */
      zlog_warn ("Packet %s [Hello:RECV]: O-bit abuse?",
		 inet_ntoa (ospfh->router_id));
#ifdef STRICT_OBIT_USAGE_CHECK
      return;                                     /* Reject this packet. */
#else /* STRICT_OBIT_USAGE_CHECK */
      UNSET_FLAG (hello->options, OSPF_OPTION_O); /* Ignore O-bit. */
#endif /* STRICT_OBIT_USAGE_CHECK */
    }
#endif /* HAVE_OPAQUE_LSA */

  /* new for NSSA is to ensure that NP is on and E is off */

#ifdef HAVE_NSSA
  if (oi->area->external_routing == OSPF_AREA_NSSA) 
    {
      if (! (CHECK_FLAG (OPTIONS (oi), OSPF_OPTION_NP)
	     && CHECK_FLAG (hello->options, OSPF_OPTION_NP)
	     && ! CHECK_FLAG (OPTIONS (oi), OSPF_OPTION_E)
	     && ! CHECK_FLAG (hello->options, OSPF_OPTION_E)))
	{
	  zlog_warn ("NSSA-Packet-%s[Hello:RECV]: my options: %x, his options %x", inet_ntoa (ospfh->router_id), OPTIONS (oi), hello->options);
	  return;
	}
      if (IS_DEBUG_OSPF_NSSA)
        zlog_info ("NSSA-Hello:RECV:Packet from %s:", inet_ntoa(ospfh->router_id));
    }
  else    
#endif /* HAVE_NSSA */
    /* The setting of the E-bit found in the Hello Packet's Options
       field must match this area's ExternalRoutingCapability A
       mismatch causes processing to stop and the packet to be
       dropped. The setting of the rest of the bits in the Hello
       Packet's Options field should be ignored. */
    if (CHECK_FLAG (OPTIONS (oi), OSPF_OPTION_E) !=
	CHECK_FLAG (hello->options, OSPF_OPTION_E))
      {
	zlog_warn ("Packet[Hello:RECV]: my options: %x, his options %x",
		   OPTIONS (oi), hello->options);
	return;
      }


  /* Get neighbor information from table. */
  key.family = AF_INET;
  key.prefixlen = IPV4_MAX_BITLEN;
  key.u.prefix4 = iph->ip_src;

  rn = route_node_get (oi->nbrs, &key);
  if (rn->info)
    {
      route_unlock_node (rn);
      nbr = rn->info;

      if (oi->type == OSPF_IFTYPE_NBMA && nbr->state == NSM_Attempt)
	{
	  nbr->src = iph->ip_src;
	  nbr->address = p;
	}
    }
  else
    {
      /* Create new OSPF Neighbor structure. */
      nbr = ospf_nbr_new (oi);
      nbr->state = NSM_Down;
      nbr->src = iph->ip_src;
      nbr->address = p;

      rn->info = nbr;

      nbr->nbr_nbma = NULL;

      if (oi->type == OSPF_IFTYPE_NBMA)
	{
	  struct ospf_nbr_nbma *nbr_nbma;
	  listnode node;

	  for (node = listhead (oi->nbr_nbma); node; nextnode (node))
	    {
	      nbr_nbma = getdata (node);
	      assert (nbr_nbma);
      
	      if (IPV4_ADDR_SAME(&nbr_nbma->addr, &iph->ip_src))
		{
		  nbr_nbma->nbr = nbr;
		  nbr->nbr_nbma = nbr_nbma;

		  if (nbr_nbma->t_poll)
		    OSPF_POLL_TIMER_OFF (nbr_nbma->t_poll);
		  
		  nbr->state_change = nbr_nbma->state_change + 1;
		}
	    }
	}
      
      /* New nbr, save the crypto sequence number if necessary */
      if (ntohs (ospfh->auth_type) == OSPF_AUTH_CRYPTOGRAPHIC)
	nbr->crypt_seqnum = ospfh->u.crypt.crypt_seqnum;

      if (IS_DEBUG_OSPF_EVENT)
	zlog_info ("NSM[%s:%s]: start", IF_NAME (nbr->oi),
		   inet_ntoa (nbr->router_id));
    }
  
  nbr->router_id = ospfh->router_id;

  old_state = nbr->state;

  /* Add event to thread. */
  OSPF_NSM_EVENT_EXECUTE (nbr, NSM_HelloReceived);

  /*  RFC2328  Section 9.5.1
      If the router is not eligible to become Designated Router,
      (snip)   It	must also send an Hello	Packet in reply	to an
      Hello Packet received from any eligible neighbor (other than
      the	current	Designated Router and Backup Designated	Router).  */
  if (oi->type == OSPF_IFTYPE_NBMA)
    if (PRIORITY(oi) == 0 && hello->priority > 0
	&& IPV4_ADDR_CMP(&DR(oi),  &iph->ip_src)
	&& IPV4_ADDR_CMP(&BDR(oi), &iph->ip_src))
      OSPF_NSM_TIMER_ON (nbr->t_hello_reply, ospf_hello_reply_timer,
			 OSPF_HELLO_REPLY_DELAY);

  /* on NBMA network type, it happens to receive bidirectional Hello packet
     without advance 1-Way Received event.
     To avoid incorrect DR-seletion, raise 1-Way Received event.*/
  if (oi->type == OSPF_IFTYPE_NBMA &&
      (old_state == NSM_Down || old_state == NSM_Attempt))
    {
      OSPF_NSM_EVENT_EXECUTE (nbr, NSM_OneWayReceived);
      nbr->priority = hello->priority;
      nbr->d_router = hello->d_router;
      nbr->bd_router = hello->bd_router;
      return;
    }

  if (ospf_nbr_bidirectional (&oi->ospf->router_id, hello->neighbors,
			      size - OSPF_HELLO_MIN_SIZE))
    {
      OSPF_NSM_EVENT_EXECUTE (nbr, NSM_TwoWayReceived);
      nbr->options |= hello->options;
    }
  else
    {
      OSPF_NSM_EVENT_EXECUTE (nbr, NSM_OneWayReceived);
      /* Set neighbor information. */
      nbr->priority = hello->priority;
      nbr->d_router = hello->d_router;
      nbr->bd_router = hello->bd_router;
      return;
    }

  /* If neighbor itself declares DR and no BDR exists,
     cause event BackupSeen */
  if (IPV4_ADDR_SAME (&nbr->address.u.prefix4, &hello->d_router))
    if (hello->bd_router.s_addr == 0 && oi->state == ISM_Waiting)
      OSPF_ISM_EVENT_SCHEDULE (oi, ISM_BackupSeen);

  /* neighbor itself declares BDR. */
  if (oi->state == ISM_Waiting &&
      IPV4_ADDR_SAME (&nbr->address.u.prefix4, &hello->bd_router))
    OSPF_ISM_EVENT_SCHEDULE (oi, ISM_BackupSeen);

  /* had not previously. */
  if ((IPV4_ADDR_SAME (&nbr->address.u.prefix4, &hello->d_router) &&
       IPV4_ADDR_CMP (&nbr->address.u.prefix4, &nbr->d_router)) ||
      (IPV4_ADDR_CMP (&nbr->address.u.prefix4, &hello->d_router) &&
       IPV4_ADDR_SAME (&nbr->address.u.prefix4, &nbr->d_router)))
    OSPF_ISM_EVENT_SCHEDULE (oi, ISM_NeighborChange);

  /* had not previously. */
  if ((IPV4_ADDR_SAME (&nbr->address.u.prefix4, &hello->bd_router) &&
       IPV4_ADDR_CMP (&nbr->address.u.prefix4, &nbr->bd_router)) ||
      (IPV4_ADDR_CMP (&nbr->address.u.prefix4, &hello->bd_router) &&
       IPV4_ADDR_SAME (&nbr->address.u.prefix4, &nbr->bd_router)))
    OSPF_ISM_EVENT_SCHEDULE (oi, ISM_NeighborChange);

  /* Neighbor priority check. */
  if (nbr->priority >= 0 && nbr->priority != hello->priority)
    OSPF_ISM_EVENT_SCHEDULE (oi, ISM_NeighborChange);

  /* Set neighbor information. */
  nbr->priority = hello->priority;
  nbr->d_router = hello->d_router;
  nbr->bd_router = hello->bd_router;
}

/* Save DD flags/options/Seqnum received. */
void
ospf_db_desc_save_current (struct ospf_neighbor *nbr,
			   struct ospf_db_desc *dd)
{
  nbr->last_recv.flags = dd->flags;
  nbr->last_recv.options = dd->options;
  nbr->last_recv.dd_seqnum = ntohl (dd->dd_seqnum);
}

/* Process rest of DD packet. */
static void
ospf_db_desc_proc (struct stream *s, struct ospf_interface *oi,
		   struct ospf_neighbor *nbr, struct ospf_db_desc *dd,
		   u_int16_t size)
{
  struct ospf_lsa *new, *find;
  struct lsa_header *lsah;

  stream_forward (s, OSPF_DB_DESC_MIN_SIZE);
  for (size -= OSPF_DB_DESC_MIN_SIZE;
       size >= OSPF_LSA_HEADER_SIZE; size -= OSPF_LSA_HEADER_SIZE) 
    {
      lsah = (struct lsa_header *) STREAM_PNT (s);
      stream_forward (s, OSPF_LSA_HEADER_SIZE);

      /* Unknown LS type. */
      if (lsah->type < OSPF_MIN_LSA || lsah->type >= OSPF_MAX_LSA)
	{
	  zlog_warn ("Pakcet [DD:RECV]: Unknown LS type %d.", lsah->type);
	  OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_SeqNumberMismatch);
	  return;
	}

#ifdef HAVE_OPAQUE_LSA
      if (IS_OPAQUE_LSA (lsah->type)
      &&  ! CHECK_FLAG (nbr->options, OSPF_OPTION_O))
        {
          zlog_warn ("LSA[Type%d:%s]: Opaque capability mismatch?", lsah->type, inet_ntoa (lsah->id));
          OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_SeqNumberMismatch);
          return;
        }
#endif /* HAVE_OPAQUE_LSA */

      switch (lsah->type)
        {
        case OSPF_AS_EXTERNAL_LSA:
#ifdef HAVE_OPAQUE_LSA
	case OSPF_OPAQUE_AS_LSA:
#endif /* HAVE_OPAQUE_LSA */
#ifdef HAVE_NSSA
          /* Check for stub area.  Reject if AS-External from stub but
             allow if from NSSA. */
          if (oi->area->external_routing == OSPF_AREA_STUB)
#else /* ! HAVE_NSSA */
          if (oi->area->external_routing != OSPF_AREA_DEFAULT)
#endif /* HAVE_NSSA */
            {
              zlog_warn ("Packet [DD:RECV]: LSA[Type%d:%s] from %s area.",
                         lsah->type, inet_ntoa (lsah->id),
                         (oi->area->external_routing == OSPF_AREA_STUB) ?\
                         "STUB" : "NSSA");
              OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_SeqNumberMismatch);
              return;
            }
          break;
	default:
	  break;
        }

      /* Create LS-request object. */
      new = ospf_ls_request_new (lsah);