/*
 *	BIRD -- OSPF
 *
 *	(c) 1999 - 2000 Ondrej Filip <feela@network.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "ospf.h"

/**
 * ospf_dbdes_tx - transmit database description packet
 * @n: neighbor
 *
 * Sending of a database description packet is described in 10.6 of RFC 2328.
 * Reception of each packet is acknowledged in the sequence number of another.
 * When I send a packet to a neighbor I keep a copy in a buffer. If the neighbor
 * does not reply, I don't create a new packet but just send the content
 * of the buffer.
 */
void
ospf_dbdes_tx(struct ospf_neighbor *n)
{
  struct ospf_dbdes_packet *pkt;
  struct ospf_packet *op;
  struct ospf_iface *ifa=n->ifa;
  struct ospf_area *oa=ifa->oa;
  u16 length;
  struct proto *p;
  u16 i,j;
  u8 *aa,*bb;

  if((oa->rt==NULL)||(EMPTY_LIST(oa->lsal))) originate_rt_lsa(oa);

  p=(struct proto *)(ifa->proto);

  switch(n->state)
  {
    case NEIGHBOR_EXSTART:		/* Send empty packets */
      n->myimms.bit.i=1;
      pkt=(struct ospf_dbdes_packet *)(ifa->ip_sk->tbuf);
      op=(struct ospf_packet *)pkt;
      fill_ospf_pkt_hdr(ifa, pkt, DBDES_P);
      pkt->iface_mtu=htons(ifa->iface->mtu);	/* FIXME NOT for VLINK! */
      pkt->options= ifa->options;
      pkt->imms=n->myimms;
      pkt->ddseq=htonl(n->dds);
      length=sizeof(struct ospf_dbdes_packet);
      op->length=htons(length);
      ospf_pkt_finalize(ifa, op);
      sk_send_to(ifa->ip_sk,length, n->ip, OSPF_PROTO);
      OSPF_TRACE(D_PACKETS, "DB_DES (I) sent to %I via %s.", n->ip,
        ifa->iface->name);
      break;

    case NEIGHBOR_EXCHANGE:
      n->myimms.bit.i=0;

      if(((n->myimms.bit.ms) && (n->dds==n->ddr+1)) ||
         ((!(n->myimms.bit.ms)) && (n->dds==n->ddr)))
      {
        snode *sn;			/* Send next */
        struct ospf_lsa_header *lsa;

	pkt=n->ldbdes;
        op=(struct ospf_packet *)pkt;
	
        fill_ospf_pkt_hdr(ifa, pkt, DBDES_P);
        pkt->iface_mtu=htons(ifa->iface->mtu);
        pkt->options= ifa->options;
	pkt->ddseq=htonl(n->dds);

	j=i=(ifa->iface->mtu-sizeof(struct ospf_dbdes_packet)-SIPH)/
		sizeof(struct ospf_lsa_header);	/* Number of possible lsaheaders to send */
	lsa=(n->ldbdes+sizeof(struct ospf_dbdes_packet));

	if(n->myimms.bit.m)
	{
	  sn=s_get(&(n->dbsi));

	  DBG("Number of LSA: %d\n", j);
	  for(;i>0;i--)
	  {
	    struct top_hash_entry *en;
	  
	    en=(struct top_hash_entry *)sn;
	    htonlsah(&(en->lsa), lsa);
	    DBG("Working on: %d\n", i);
            DBG("\tX%01x %-1I %-1I %p\n", en->lsa.type, en->lsa.id,
              en->lsa.rt, en->lsa_body);

	    if(sn==STAIL(n->ifa->oa->lsal))
	    {
	      i--;
	      break;	/* Should set some flag? */
  	    }
	    sn=sn->next;
	    lsa++;
	  }

	  if(sn==STAIL(n->ifa->oa->lsal))
	  {
	    DBG("Number of LSA NOT sent: %d\n", i);
	    DBG("M bit unset.\n");
	    n->myimms.bit.m=0;	/* Unset more bit */
	  }
	  else s_put(&(n->dbsi),sn);
	}

        pkt->imms.byte=n->myimms.byte;

	length=(j-i)*sizeof(struct ospf_lsa_header)+
		sizeof(struct ospf_dbdes_packet);
	op->length=htons(length);
	
        ospf_pkt_finalize(ifa, op);
        DBG("%s: DB_DES (M) prepared for %I.\n", p->name, n->ip);
      }

    case NEIGHBOR_LOADING:
    case NEIGHBOR_FULL:
      aa=ifa->ip_sk->tbuf;
      bb=n->ldbdes;
      op=n->ldbdes;
      length=ntohs(op->length);

      for(i=0; i<length; i++)
      {
        *(aa+i)=*(bb+i);	/* Copy last sent packet again */
      }

      sk_send_to(ifa->ip_sk,length, n->ip, OSPF_PROTO);
      OSPF_TRACE(D_PACKETS, "DB_DES (M) sent to %I via %s.", n->ip,
        ifa->iface->name);
      if(! n->myimms.bit.ms)
      {
        if((n->myimms.bit.m==0) && (n->imms.bit.m==0) &&
          (n->state==NEIGHBOR_EXCHANGE))
	{
          ospf_neigh_sm(n, INM_EXDONE);
	}
      }
      break;

    default:				/* Ignore it */
      break;
  }
}

void
ospf_dbdes_reqladd(struct ospf_dbdes_packet *ps, struct proto *p,
  struct ospf_neighbor *n)
{
  struct ospf_lsa_header *plsa,lsa;
  struct top_hash_entry *he,*sn;
  struct top_graph *gr;
  struct ospf_packet *op;
  int i,j;

  gr=n->ifa->oa->gr;
  op=(struct ospf_packet *)ps;

  plsa=(void *)(ps+1);

  j=(ntohs(op->length)-sizeof(struct ospf_dbdes_packet))/
    sizeof( struct ospf_lsa_header);

  for(i=0;i<j;i++)
  {
    ntohlsah(plsa+i, &lsa);
    if(((he=ospf_hash_find(gr,lsa.id,lsa.rt,lsa.type))==NULL)||
      (lsa_comp(&lsa, &(he->lsa))==1))
    {
      /* Is this condition necessary? */
      if(ospf_hash_find(n->lsrqh,lsa.id,lsa.rt,lsa.type)==NULL)
      {
        sn=ospf_hash_get(n->lsrqh,lsa.id,lsa.rt,lsa.type);
        ntohlsah(plsa+i, &(sn->lsa));
        s_add_tail(&(n->lsrql), SNODE sn);
      }
    }
  }
}

void
ospf_dbdes_rx(struct ospf_dbdes_packet *ps, struct proto *p,
  struct ospf_iface *ifa, u16 size)
{
  u32 nrid, myrid;
  struct ospf_neighbor *n;

  nrid=ntohl(((struct ospf_packet *)ps)->routerid);

  myrid=p->cf->global->router_id;

  if((n=find_neigh(ifa, nrid))==NULL)
  {
    OSPF_TRACE(D_PACKETS, "Received dbdes from unknown neigbor! %I.",
      nrid);
    return ;
  }

  if(ifa->iface->mtu<size)
  {
    OSPF_TRACE(D_PACKETS, "Received dbdes larger than MTU from %I!", n->ip);
    return ;
  }

  OSPF_TRACE(D_PACKETS, "Received dbdes from %I via %s.", n->ip,
    ifa->iface->name);
  ospf_neigh_sm(n, INM_HELLOREC);

  switch(n->state)
  {
    case NEIGHBOR_DOWN:
    case NEIGHBOR_ATTEMPT:
    case NEIGHBOR_2WAY:
        return;
      break;
    case NEIGHBOR_INIT:
        ospf_neigh_sm(n, INM_2WAYREC);
	if(n->state!=NEIGHBOR_EXSTART) return;
    case NEIGHBOR_EXSTART:
        if((ps->imms.bit.m && ps->imms.bit.ms && ps->imms.bit.i)
          && (n->rid > myrid) &&
          (size == sizeof(struct ospf_dbdes_packet)))
        {
          /* I'm slave! */
          n->dds=ntohl(ps->ddseq);
	  n->ddr=ntohl(ps->ddseq);
	  n->options=ps->options;
	  n->myimms.bit.ms=0;
	  n->imms.byte=ps->imms.byte;
          OSPF_TRACE(D_PACKETS, "I'm slave to %I.", n->ip);
	  ospf_neigh_sm(n, INM_NEGDONE);
	  ospf_dbdes_tx(n);
	  break;
        }
        else
        {
          if(((ps->imms.bit.i==0) && (ps->imms.bit.ms==0)) &&
            (n->rid < myrid) && (n->dds == ntohl(ps->ddseq)))
          {
            /* I'm master! */
	    n->options=ps->options;
            n->ddr=ntohl(ps->ddseq)-1;
            n->imms.byte=ps->imms.byte;
            OSPF_TRACE(D_PACKETS, "I'm master to %I.", n->ip);
	    ospf_neigh_sm(n, INM_NEGDONE);
          }
	  else
          {
            DBG("%s: Nothing happend to %I (imms=%u)\n", p->name, n->ip,
              ps->imms.byte);
            break;
          }
        }
        if(ps->imms.bit.i) break;
    case NEIGHBOR_EXCHANGE:
	if((ps->imms.byte==n->imms.byte) && (ps->options==n->options) &&
	  (ntohl(ps->ddseq)==n->ddr))
        {
          /* Duplicate packet */
          OSPF_TRACE(D_PACKETS, "Received duplicate dbdes from %I.", n->ip);
	  if(n->imms.bit.ms==0)
	  {
            ospf_dbdes_tx(n);
	  }
          return;
        }

        n->ddr=ntohl(ps->ddseq);

	if(ps->imms.bit.ms!=n->imms.bit.ms) /* M/S bit differs */
        {
          log("SEQMIS-BIT-MS\n");
          ospf_neigh_sm(n, INM_SEQMIS);
	  break;
        }

	if(ps->imms.bit.i)	/* I bit is set */
        {
          log("SEQMIS-BIT-I\n");
          ospf_neigh_sm(n, INM_SEQMIS);
	  break;
        }

	n->imms.byte=ps->imms.byte;

	if(ps->options!=n->options)	/* Options differs */
        {
          log("SEQMIS-OPT\n");
          ospf_neigh_sm(n, INM_SEQMIS);
	  break;
        }

	if(n->myimms.bit.ms)
        {
          if(ntohl(ps->ddseq)!=n->dds)		/* MASTER */
	  {
            log("SEQMIS-MASTER\n");
	    ospf_neigh_sm(n, INM_SEQMIS);
	    break;
	  }
	  n->dds++;
          DBG("Incrementing dds\n");
	  ospf_dbdes_reqladd(ps,p,n);
	  if((n->myimms.bit.m==0) && (ps->imms.bit.m==0))
	  {
	    ospf_neigh_sm(n, INM_EXDONE);
	  }
	  else
	  {
	    ospf_dbdes_tx(n);
	  }

        }
	else
        {
          if(ntohl(ps->ddseq)!=(n->dds+1))	/* SLAVE */
	  {
            log("SEQMIS-SLAVE\n");
	    ospf_neigh_sm(n, INM_SEQMIS);
	    break;
	  }
	  n->ddr=ntohl(ps->ddseq);
	  n->dds=ntohl(ps->ddseq);
	  ospf_dbdes_reqladd(ps,p,n);
	  ospf_dbdes_tx(n);
        }

      break;
    case NEIGHBOR_LOADING:
    case NEIGHBOR_FULL:
	if((ps->imms.byte==n->imms.byte) && (ps->options==n->options) &&
	  (ntohl(ps->ddseq)==n->ddr)) /* Only duplicate are accepted */
        {
          OSPF_TRACE(D_PACKETS, "Received duplicate dbdes from %I.",n->ip);
          return;
        }
	else
        {
	  log("SEQMIS-FULL\n");
	  ospf_neigh_sm(n, INM_SEQMIS);
        }
      break;
    defaut:
      bug("%s: Received dbdes from %I in undefined state.", p->name, n->ip);
      break;
   }
}