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

#define LOCAL_DEBUG

#include <string.h>

#include "nest/bird.h"
#include "nest/route.h"
#include "conf/conf.h"
#include "lib/checksum.h"

#include "ospf.h"

#define IAMMASTER(x) ((x) & DBDES_MS)
#define INISET(x) ((x) & DBDES_I)


void
fill_ospf_pkt_hdr(struct ospf_iface *ifa, void *buf, u8 h_type)
{
  struct ospf_packet *pkt;
  struct proto *p;
  
  p=(struct proto *)(ifa->proto);

  pkt=(struct ospf_packet *)buf;

  pkt->version=OSPF_VERSION;

  pkt->type=h_type;

  pkt->routerid=htonl(p->cf->global->router_id);
  pkt->areaid=htonl(ifa->area);
  pkt->autype=htons(ifa->autype);
  pkt->checksum=0;
}

void
ospf_tx_authenticate(struct ospf_iface *ifa, struct ospf_packet *pkt)
{
  /* FIXME Nothing done */
}

void
ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt)
{
  ospf_tx_authenticate(ifa, pkt);

  /* Count checksum */
  pkt->checksum=ipsum_calculate(pkt,sizeof(struct ospf_packet)-8,
    (pkt+1),ntohs(pkt->length)-sizeof(struct ospf_packet),NULL);
}

void
ospf_dbdes_tx(struct ospf_neighbor *n)
{
  struct ospf_dbdes_packet *pkt;
  struct ospf_packet *op;
  struct ospf_iface *ifa;
  u16 length;
  struct proto *p;

  ifa=n->ifa;

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

  switch(n->state)
  {
    case NEIGHBOR_EXSTART:		/* Send empty packets */
      pkt=(struct ospf_dbdes_packet *)(ifa->ip_sk->tbuf);
      op=(struct ospf_packet *)pkt;

      fill_ospf_pkt_hdr(ifa, pkt, DBDES);
      pkt->iface_mtu= ((struct iface *)ifa)->mtu;
      pkt->options= ifa->options;
      pkt->imms=n->myimms;
      pkt->ddseq=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);
      debug("%s: DB_DES sent for %u.\n", p->name, n->rid);

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

void
rxmt_timer_hook(timer *timer)
{
  struct ospf_iface *ifa;
  struct proto *p;
  struct ospf_neighbor *n;

  ifa=(struct ospf_iface *)timer->data;
  p=(struct proto *)(ifa->proto);
  debug("%s: RXMT timer fired on interface %s.\n",
    p->name, ifa->iface->name);
  WALK_LIST (n, ifa->neigh_list)	/* Try to send db_des */
  {
    ospf_dbdes_tx(n);
  }
}

struct ospf_neighbor *
find_neigh(struct ospf_iface *ifa, u32 rid)
{
  struct ospf_neighbor *n;

  WALK_LIST (n, ifa->neigh_list)
    if(n->rid == rid)
      return n;
  return NULL;
}

void
neigh_chstate(struct ospf_neighbor *n, u8 state)
{
  struct ospf_iface *ifa;
  struct proto *p;

  if(n->state!=state)
  {
    ifa=n->ifa;
    p=(struct proto *)(ifa->proto);
  
    debug("%s: Neigbor '%u' changes state from %u to %u.\n", p->name, n->rid,
      n->state, state);
    n->state=state;
  }
}


/* Try to build neighbor adjacency (if does not exists) */
void
tryadj(struct ospf_neighbor *n, struct proto *p)
{
  DBG("%s: Going to build adjacency.\n", p->name);
  neigh_chstate(n,NEIGHBOR_EXSTART);
  if(n->adj==0)	/* First time adjacency */
  {
    n->dds=random_u32();
  }
  n->dds++;
  n->myimms=(DBDES_MS | DBDES_M | DBDES_I );
  tm_start(n->ifa->rxmt_timer,1);	/* Or some other number ? */
}

/* Neighbor is inactive for a long time. Remove it. */
void
neighbor_timer_hook(timer *timer)
{
  struct ospf_neighbor *n;
  struct ospf_iface *ifa;
  struct proto *p;

  n=(struct ospf_neighbor *)timer->data;
  ifa=n->ifa;
  p=(struct proto *)(ifa->proto);
  debug("%s: Inactivity timer fired on interface %s for neighbor %u.\n",
    p->name, ifa->iface->name, n->rid);
  tm_stop(n->inactim);
  rfree(n->inactim);
  rem_node(NODE n);
  mb_free(n);
  debug("%s: Deleting neigbor.\n", p->name);
}

void
iface_chstate(struct ospf_iface *ifa, u8 state)
{
  struct proto *p;

  p=(struct proto *)(ifa->proto);
  debug("%s: Changing state of iface: %s from %u into %u.\n",
    p->name, ifa->iface->name, ifa->state, state);
  ifa->state=state;
}

struct ospf_neighbor *
electbdr(list nl)
{
  struct ospf_neighbor *neigh,*n1,*n2;

  n1=NULL;
  n2=NULL;
  WALK_LIST (neigh, nl)		/* First try those decl. themselves */
  {
    if(neigh->state>=NEIGHBOR_2WAY)	/* Higher than 2WAY */
      if(neigh->priority>0)		/* Eligible */
        if(neigh->rid!=neigh->dr)	/* And not declaring itself DR */
	{
	  if(neigh->rid==neigh->bdr)	/* Declaring BDR */
          {
            if(n1!=NULL)
            {
              if(neigh->priority>n1->priority) n1=neigh;
	      else if(neigh->priority==n1->priority)
	          if(neigh->rid>n1->rid) n1=neigh;
            }
	    else
            {
              n1=neigh;
            }
          }
	  else				/* And NOT declaring BDR */
          {
            if(n2!=NULL)
            {
              if(neigh->priority>n2->priority) n2=neigh;
	      else if(neigh->priority==n2->priority)
	          if(neigh->rid>n2->rid) n2=neigh;
            }
	    else
            {
              n2=neigh;
            }
          }
      }
  }
  if(n1==NULL) n1=n2;

  return(n1);
}

struct ospf_neighbor *
electdr(list nl)
{
  struct ospf_neighbor *neigh,*n;

  n=NULL;
  WALK_LIST (neigh, nl)	/* And now DR */
  {
    if(neigh->state>=NEIGHBOR_2WAY)	/* Higher than 2WAY */
      if(neigh->priority>0)		/* Eligible */
        if(neigh->rid==neigh->dr)	/* And declaring itself DR */
	{
          if(n!=NULL)
          {
            if(neigh->priority>n->priority) n=neigh;
	    else if(neigh->priority==n->priority)
	        if(neigh->rid>n->rid) n=neigh;
          }
	  else
          {
            n=neigh;
          }
      }
  }

  return(n);
}

void
install_inactim(struct ospf_neighbor *n)
{
  struct proto *p;
  struct ospf_iface *ifa;

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

  if(n->inactim==NULL)
  {
    n->inactim=tm_new(p->pool);
    n->inactim->data=n;
    n->inactim->randomize=0;
    n->inactim->hook=neighbor_timer_hook;
    n->inactim->recurrent=0;
    DBG("%s: Installing inactivity timer.\n", p->name);
  }
}

void
restart_inactim(struct ospf_neighbor *n)
{
  tm_start(n->inactim,n->ifa->deadc*n->ifa->helloint);
}

void
restart_hellotim(struct ospf_iface *ifa)
{
  tm_start(ifa->hello_timer,ifa->helloint);
}

void
restart_waittim(struct ospf_iface *ifa)
{
  tm_start(ifa->wait_timer,ifa->waitint);
}

int
can_do_adj(struct ospf_neighbor *n)
{
  struct ospf_iface *ifa;
  struct proto *p;
  int i;

  ifa=n->ifa;
  p=(struct proto *)(ifa->proto);
  i=0;

  switch(ifa->type)
  {
    case OSPF_IT_PTP:
    case OSPF_IT_VLINK:
      i=1;
      break;
    case OSPF_IT_BCAST:
    case OSPF_IT_NBMA:
      switch(ifa->state)
      {
        case OSPF_IS_DOWN:
          die("%s: Iface %s in down state?", p->name, ifa->iface->name);
          break;
        case OSPF_IS_WAITING:
          DBG("%s: Neighbor? on iface %s\n",p->name, ifa->iface->name);
          break;
        case OSPF_IS_DROTHER:
          if(((n->rid==ifa->drid) || (n->rid==ifa->bdrid))
            && (n->state==NEIGHBOR_2WAY)) i=1;
          break;
        case OSPF_IS_PTP:
        case OSPF_IS_BACKUP:
        case OSPF_IS_DR:
          if(n->state==NEIGHBOR_2WAY) i=1;
          break;
        default:
          die("%s: Iface %s in unknown state?",p->name, ifa->iface->name);
          break;
      }
      break;
    default:
      die("%s: Iface %s is unknown type?",p->name, ifa->iface->name);
      break;
  }
  DBG("%s: Iface %s can_do_adj=%d\n",p->name, ifa->iface->name,i);
  return i;
}

void
ospf_neigh_sm(struct ospf_neighbor *n, int event)
	/* Interface state machine */
{
  struct proto *p;

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

  switch(event)
  {
    case INM_START:
      neigh_chstate(n,NEIGHBOR_ATTEMPT);
      /* FIXME No NBMA now */
      break;
    case INM_HELLOREC:
      switch(n->state)
      {
        case NEIGHBOR_ATTEMPT:
	case NEIGHBOR_DOWN:
	  neigh_chstate(n,NEIGHBOR_INIT);
	default:
          restart_inactim(n);
	  break;
      }
      break;
    case INM_2WAYREC:
      if(n->state==NEIGHBOR_INIT)
      {
        /* Can In build adjacency? */
        neigh_chstate(n,NEIGHBOR_2WAY);
	if(can_do_adj(n))
        {
          neigh_chstate(n,NEIGHBOR_EXSTART);
          tryadj(n,p);
        }
      }
      break;
    case INM_NEGDONE:
      if(n->state==NEIGHBOR_EXSTART)
      {
        neigh_chstate(n,NEIGHBOR_EXCHANGE);
        /* FIXME Go on... */
      }
      break;
    case INM_EXDONE:
      break;
    case INM_LOADDONE:
      break;
    case INM_ADJOK:
        switch(n->state)
        {
          case NEIGHBOR_2WAY:
        /* Can In build adjacency? */
            if(can_do_adj(n))
            {
              neigh_chstate(n,NEIGHBOR_EXSTART);
              tryadj(n,p);
            }
            break;
          default:
	    if(n->state>=NEIGHBOR_EXSTART)
              if(!can_do_adj(n))
              {
                neigh_chstate(n,NEIGHBOR_2WAY);
		/* FIXME Stop timers, kill database... */
              }
            break;
        }
      break;
    case INM_SEQMIS:
    case INM_BADLSREQ:
      debug("%s: Bad LS req!\n", p->name);
      if(n->state>=NEIGHBOR_EXCHANGE)
      {
        neigh_chstate(n,NEIGHBOR_EXSTART);
	/* Go on....*/
      }
      break;
    case INM_KILLNBR:
    case INM_LLDOWN:
    case INM_INACTTIM:
      neigh_chstate(n,NEIGHBOR_DOWN);
      break;
    case INM_1WAYREC:
      if(n->state>=NEIGHBOR_2WAY)
      {
        neigh_chstate(n,NEIGHBOR_DOWN);
      }
      break;
    default:
      die("%s: INM - Unknown event?",p->name);
      break;
  }
}


void
bdr_election(struct ospf_iface *ifa, struct proto *p)
{
  struct ospf_neighbor *neigh,*ndr,*nbdr,me;
  u32 myid, ndrid, nbdrid;
  int doadj;

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

  DBG("%s: (B)DR election.\n",p->name);

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

  me.state=NEIGHBOR_2WAY;
  me.rid=myid;
  me.priority=ifa->priority;
  me.dr=ifa->drid;
  me.bdr=ifa->bdrid;

  add_tail(&ifa->neigh_list, NODE &me);

  nbdr=electbdr(ifa->neigh_list);
  ndr=electdr(ifa->neigh_list);

  if(ndr==NULL) ndr=nbdr;

  if(((ifa->drid==myid) && (ndr->rid!=myid))
    || ((ifa->drid!=myid) && (ndr->rid==myid))
    || ((ifa->bdrid==myid) && (nbdr->rid!=myid)) 
    || ((ifa->bdrid!=myid) && (nbdr->rid==myid)))
  {
    if(ndr==NULL) ifa->drid=me.dr=0;
    else ifa->drid=me.dr=ndr->rid;

    if(nbdr==NULL) ifa->bdrid=me.bdr=0;
    else ifa->bdrid=me.bdr=nbdr->rid;

    nbdr=electbdr(ifa->neigh_list);
    ndr=electdr(ifa->neigh_list);
  }

  if(ndr==NULL) ifa->drid=0;
  if(ndr==NULL) ndrid=0;
  else ndrid=ndr->rid;

  if(nbdr==NULL) nbdrid=0;
  else nbdrid=nbdr->rid;

  doadj=0;
  if((ifa->drid!=ndrid) || (ifa->bdrid!=nbdrid)) doadj=1;
  ifa->drid=ndrid;
  ifa->bdrid=nbdrid;

  DBG("%s: DR=%u, BDR=%u\n",p->name, ifa->drid, ifa->bdrid);

  if(myid==ifa->drid) iface_chstate(ifa, OSPF_IS_DR);
  else
  {
    if(myid==ifa->bdrid) iface_chstate(ifa, OSPF_IS_BACKUP);
    else iface_chstate(ifa, OSPF_IS_DROTHER);
  }

  rem_node(NODE &me);

  if(doadj)
  {
    WALK_LIST (neigh, ifa->neigh_list)
    {
      ospf_neigh_sm(neigh, INM_ADJOK);
    }
  }
}

void
downint(struct ospf_iface *ifa)
{
  /* FIXME: Delete all neighbors! */
}

void
ospf_int_sm(struct ospf_iface *ifa, int event)
{
  struct proto *p;

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

  DBG("%s: SM on iface %s. Event is %d.\n",
    p->name, ifa->iface->name, event);

  switch(event)
  {
    case ISM_UP:
      if(ifa->state==OSPF_IS_DOWN)
      {
        restart_hellotim(ifa);
        if((ifa->type==OSPF_IT_PTP) || (ifa->type==OSPF_IT_VLINK))
        {
          iface_chstate(ifa, OSPF_IS_PTP);
        }
        else
        {
          if(ifa->priority==0)
          {
            iface_chstate(ifa, OSPF_IS_DROTHER);
          } 
          else
          {
             iface_chstate(ifa, OSPF_IS_WAITING);
             restart_waittim(ifa);
          }
        }
      }
      break;
    case ISM_BACKS:
    case ISM_WAITF:
      if(ifa->state==OSPF_IS_WAITING)
      {
        bdr_election(ifa ,p);
      }
      break;
    case ISM_NEICH:
      if((ifa->state==OSPF_IS_DROTHER) || (ifa->state==OSPF_IS_DR) ||
        (ifa->state==OSPF_IS_BACKUP))
      {
        bdr_election(ifa ,p);
      }
    case ISM_DOWN:
      iface_chstate(ifa, OSPF_IS_DOWN);
      downint(ifa);
      break;
    case ISM_LOOP:	/* Useless? */
      iface_chstate(ifa, OSPF_IS_LOOP);
      downint(ifa);
      break;
    case ISM_UNLOOP:
      iface_chstate(ifa, OSPF_IS_DOWN);
      break;
    default:
      die("%s: ISM - Unknown event?",p->name);
      break;
  }
	
}

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;
  u8 i;

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

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

  if((n=find_neigh(ifa, nrid))==NULL)
  {
    debug("%s: Received dbdes from unknown neigbor! (%u)\n", p->name,
      nrid);
    return ;
  }

  if(ifa->iface->mtu<size)
  {
    debug("%s: Received dbdes larger than MTU from (%u)!\n", p->name, nrid);
    return ;
  }

  switch(n->state)
  {
    case NEIGHBOR_DOWN:
    case NEIGHBOR_ATTEMPT:
    case NEIGHBOR_2WAY:
        debug("%s: Received dbdes from %u in bad state. (%u)\n", p->name, nrid);
        return;
      break;
    case NEIGHBOR_INIT:
        ospf_neigh_sm(n, INM_2WAYREC);
	if(n->state!=NEIGHBOR_EXSTART) return;
    case NEIGHBOR_EXSTART:
        if(ps->imms==(DBDES_I|DBDES_M|DBDES_MS) && (n->rid > myrid) &&
          (size == sizeof(struct ospf_dbdes_packet)))
        {
          /* I'm slave! */
          n->dds=ps->ddseq;
	  n->options=ps->options;
	  n->myimms=(n->myimms && DBDES_M);
	  n->ddr=ps->ddseq;
	  n->imms=ps->imms;
          debug("%s: I'm slave to %u. \n", p->name, nrid);
	  ospf_neigh_sm(n, INM_NEGDONE);
        }
        else
        {
          if(((ps->imms & (DBDES_I|DBDES_MS))== 0) && (n->rid < myrid) &&
            (n->dds == ps->ddseq))
          {
            /* I'm master! */
	    n->options=ps->options;
            n->ddr=ps->ddseq;
            n->imms=ps->imms;
            debug("%s: I'm master to %u. \n", p->name, nrid);
	    ospf_neigh_sm(n, INM_NEGDONE);
          }
	  else
          {
            debug("%s: Nothing happend to %u (imms=%u)", p->name, nrid,
              ps->imms);
            break;
          }
        }
        break;	/* I should probably continue processing packet */

    case NEIGHBOR_EXCHANGE:
	if((ps->imms==n->imms) && (ps->options=n->options) &&
	  (ps->ddseq==n->dds))
        {
          /* Duplicate packet */
          debug("%s: Received duplicate dbdes from (%u)!\n", p->name, nrid);
	  if(!IAMMASTER(n->imms))
	  {
            ospf_dbdes_tx(n);
	  }
          return;
        }

	if(IAMMASTER(ps->imms)!=IAMMASTER(n->myimms)) /* M/S bit differs */
        {
          ospf_neigh_sm(n, INM_SEQMIS);
	  break;
        }

	if(INISET(ps->imms))	/* I bit is set */
        {
          ospf_neigh_sm(n, INM_SEQMIS);
	  break;
        }

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

	if(IAMMASTER(n->myimms))
        {
          if(ps->ddseq!=n->dds)
	  {
	    ospf_neigh_sm(n, INM_SEQMIS);
	    break;
	  }
        }
	else
        {
          if(ps->ddseq!=(n->dds+1))
	  {
	    ospf_neigh_sm(n, INM_SEQMIS);
	    break;
	  }
        }

	/* FIXME: Packet accepted, go on */

      break;
    case NEIGHBOR_LOADING:
    case NEIGHBOR_FULL:
	if((ps->imms==n->imms) && (ps->options=n->options) &&
	  (ps->ddseq==n->dds)) /* Only duplicate are accepted */
        {
          debug("%s: Received duplicate dbdes from (%u)!\n", p->name, nrid);
          return;
        }
	else
        {
	  ospf_neigh_sm(n, INM_SEQMIS);
        }
      break;
    defaut:
      die("%s: Received dbdes from %u in unknown state. (%u)\n", p->name, nrid);
      break;
   }
}

void
ospf_hello_rx(struct ospf_hello_packet *ps, struct proto *p,
  struct ospf_iface *ifa, int size, ip_addr faddr)
{
  char sip[100]; /* FIXME: Should be smaller */
  u32 nrid, *pnrid;
  struct ospf_neighbor *neigh,*n;
  u8 i,twoway;

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

  if((unsigned)ipa_mklen(ipa_ntoh(ps->netmask))!=ifa->iface->addr->pxlen)
  {
    ip_ntop(ps->netmask,sip);
    log("%s: Bad OSPF packet from %u received: bad netmask %s.",
      p->name, nrid, sip);
    log("%s: Discarding",p->name);
    return;
  }
  
  if(ntohs(ps->helloint)!=ifa->helloint)
  {
    log("%s: Bad OSPF packet from %u received: hello interval mismatch.",
      p->name, nrid);
    log("%s: Discarding",p->name);
    return;
  }

  if(ntohl(ps->deadint)!=ifa->helloint*ifa->deadc)
  {
    log("%s: Bad OSPF packet from %u received: dead interval mismatch.",
      p->name, nrid);
    log("%s: Discarding",p->name);
    return;
  }

  if(ps->options!=ifa->options)
  {
    log("%s: Bad OSPF packet from %u received: options mismatch.",
      p->name, nrid);	/* FIXME: This not good */
    log("%s: Discarding",p->name);
    return;
  }

  if((n=find_neigh(ifa, nrid))==NULL)
  {
    log("%s: New neighbor found: %u.", p->name,nrid);
    n=mb_alloc(p->pool, sizeof(struct ospf_neighbor));
    add_tail(&ifa->neigh_list, NODE n);
    n->rid=nrid;
    n->ip=faddr;
    n->dr=ntohl(ps->dr);
    n->bdr=ntohl(ps->bdr);
    n->priority=ps->priority;
    n->options=ps->options;
    n->ifa=ifa;
    n->adj=0;
    neigh_chstate(n,NEIGHBOR_DOWN);
    install_inactim(n);
  }
  ospf_neigh_sm(n, INM_HELLOREC);

  pnrid=(u32 *)((struct ospf_hello_packet *)(ps+1));

  twoway=0;
  for(i=0;i<size-(sizeof(struct ospf_hello_packet));i++)
  {
    if(ntohl(*(pnrid+i))==p->cf->global->router_id)
    {
      DBG("%s: Twoway received. %u\n", p->name, nrid);
      ospf_neigh_sm(n, INM_2WAYREC);
      twoway=1;
      break;
    }
  }

  if(!twoway) ospf_neigh_sm(n, INM_1WAYREC);

  /* Check priority change */
  if(n->priority!=(n->priority=ps->priority))
  {
    ospf_int_sm(ifa, ISM_NEICH);
  }

  /* Check neighbor's designed router idea */
  if((n->rid!=ntohl(ps->dr)) && (ntohl(ps->bdr)==0) &&
    (n->state>=NEIGHBOR_2WAY))
  {
    ospf_int_sm(ifa, ISM_BACKS);
  }
  if((n->rid==ntohl(ps->dr)) && (n->dr!=ntohl(ps->dr)))
  {
    ospf_int_sm(ifa, ISM_NEICH);
  }
  if((n->rid==n->dr) && (n->dr!=ntohl(ps->dr)))
  {
    ospf_int_sm(ifa, ISM_NEICH);
  }
  n->dr=ntohl(ps->dr);	/* And update it */

  /* Check neighbor's backup designed router idea */
  if((n->rid==ntohl(ps->bdr)) && (n->state>=NEIGHBOR_2WAY))
  {
    ospf_int_sm(ifa, ISM_BACKS);
  }
  if((n->rid==ntohl(ps->bdr)) && (n->bdr!=ntohl(ps->bdr)))
  {
    ospf_int_sm(ifa, ISM_NEICH);
  }
  if((n->rid==n->bdr) && (n->bdr!=ntohl(ps->bdr)))
  {
    ospf_int_sm(ifa, ISM_NEICH);
  }
  n->bdr=ntohl(ps->bdr);	/* And update it */

  ospf_neigh_sm(n, INM_HELLOREC);
}


int
ospf_rx_hook(sock *sk, int size)
{
#ifndef IPV6
  struct ospf_packet *ps;
  struct ospf_iface *ifa;
  struct proto *p;
  int i;
  u8 *pu8;


  ifa=(struct ospf_iface *)(sk->data);

  p=(struct proto *)(ifa->proto);
  DBG("%s: RX_Hook called on interface %s.\n",p->name, sk->iface->name);

  ps = (struct ospf_packet *) ipv4_skip_header(sk->rbuf, &size);
  if(ps==NULL)
  {
    log("%s: Bad OSPF packet received: bad IP header", p->name);
    log("%s: Discarding",p->name);
    return(1);
  }
  
  if((unsigned)size < sizeof(struct ospf_packet))
  {
    log("%s: Bad OSPF packet received: too short (%u bytes)", p->name, size);
    log("%s: Discarding",p->name);
    return(1);
  }

  if(ntohs(ps->length) != size)
  {
    log("%s: Bad OSPF packet received: size field does not match", p->name);
    log("%s: Discarding",p->name);
    return(1);
  }

  if(ps->version!=OSPF_VERSION)
  {
    log("%s: Bad OSPF packet received: version %u", p->name, ps->version);
    log("%s: Discarding",p->name);
    return(1);
  }

  if(!ipsum_verify(ps, 16,(void *)ps+sizeof(struct ospf_packet),
    ntohs(ps->length)-sizeof(struct ospf_packet), NULL))
  {
    log("%s: Bad OSPF packet received: bad checksum", p->name);
    log("%s: Discarding",p->name);
    return(1);
  }

  /* FIXME: Do authetification */

  if(ps->areaid!=ifa->area)
  {
    log("%s: Bad OSPF packet received: other area %ld", p->name, ps->areaid);
    log("%s: Discarding",p->name);
    return(1);
  }

  if(ntohl(ps->routerid)==p->cf->global->router_id)
  {
    log("%s: Bad OSPF packet received: received my own IP!.", p->name);
    log("%s: Discarding",p->name);
    return(1);
  }

  if(ntohl(ps->routerid)==0)
  {
    log("%s: Bad OSPF packet received: Id 0.0.0.0 is not allowed.", p->name);
    log("%s: Discarding",p->name);
    return(1);
  }
  
  /* Dump packet */
  pu8=(u8 *)(sk->rbuf+5*4);
  for(i=0;i<ntohs(ps->length);i+=4)
    DBG("%s: received %u,%u,%u,%u\n",p->name, pu8[i+0], pu8[i+1], pu8[i+2],
		    pu8[i+3]);
  debug("%s: received size: %u\n",p->name,size);

  switch(ps->type)
  {
    case HELLO:
      DBG("%s: Hello received.\n", p->name);
      ospf_hello_rx((struct ospf_hello_packet *)ps, p, ifa, size, sk->faddr);
      break;
    case DBDES:
      DBG("%s: Database description received.\n", p->name);
      ospf_dbdes_rx((struct ospf_dbdes_packet *)ps, p, ifa, size);
      break;
    case LSREQ:
      DBG("%s: Link state request received.\n", p->name);
      break;
    case LSUPD:
      DBG("%s: Link state update received.\n", p->name);
      break;
    case LSACK:
      DBG("%s: Link state ack received.\n", p->name);
      break;
    default:
      log("%s: Bad packet received: wrong type %u", p->name, ps->type);
      log("%s: Discarding",p->name);
      return(1);
  };
  DBG("\n");
#else
#error RX_Hook does not work for IPv6 now.
#endif
  return(1);
}

void
ospf_tx_hook(sock *sk)
{
  struct ospf_iface *ifa;
  struct proto *p;

  ifa=(struct ospf_iface *)(sk->data);

  p=(struct proto *)(ifa->proto);
  DBG("%s: TX_Hook called on interface %s\n", p->name,sk->iface->name);
}

void
ospf_err_hook(sock *sk, int err)
{
  struct ospf_iface *ifa;
  struct proto *p;

  ifa=(struct ospf_iface *)(sk->data);

  p=(struct proto *)(ifa->proto);
  DBG("%s: Err_Hook called on interface %s\n", p->name,sk->iface->name);
}

sock *
ospf_open_mc_socket(struct ospf_iface *ifa)
{
  sock *mcsk;
  struct proto *p;

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


  /* FIXME: No NBMA networks now */

  if(ifa->iface->flags & IF_MULTICAST)
  {
    mcsk=sk_new(p->pool);
    mcsk->type=SK_IP_MC;
    mcsk->dport=OSPF_PROTO;
    mcsk->saddr=AllSPFRouters;
    mcsk->daddr=AllSPFRouters;
    mcsk->tos=IP_PREC_INTERNET_CONTROL;
    mcsk->ttl=1;
    mcsk->rx_hook=ospf_rx_hook;
    mcsk->tx_hook=ospf_tx_hook;
    mcsk->err_hook=ospf_err_hook;
    mcsk->iface=ifa->iface;
    mcsk->rbsize=ifa->iface->mtu;
    mcsk->tbsize=ifa->iface->mtu;
    mcsk->data=(void *)ifa;
    if(sk_open(mcsk)!=0)
    {
      DBG("%s: SK_OPEN: mc open failed.\n",p->name);
      return(NULL);
    }
    DBG("%s: SK_OPEN: mc opened.\n",p->name);
    return(mcsk);
  }
  else return(NULL);
}

sock *
ospf_open_ip_socket(struct ospf_iface *ifa)
{
  sock *ipsk;
  struct proto *p;

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

  ipsk=sk_new(p->pool);
  ipsk->type=SK_IP;
  ipsk->dport=OSPF_PROTO;
  ipsk->saddr=ifa->iface->addr->ip;
  ipsk->tos=IP_PREC_INTERNET_CONTROL;
  ipsk->ttl=1;
  ipsk->rx_hook=ospf_rx_hook;
  ipsk->tx_hook=ospf_tx_hook;
  ipsk->err_hook=ospf_err_hook;
  ipsk->iface=ifa->iface;
  ipsk->rbsize=ifa->iface->mtu;
  ipsk->tbsize=ifa->iface->mtu;
  ipsk->data=(void *)ifa;
  if(sk_open(ipsk)!=0)
  {
    DBG("%s: SK_OPEN: ip open failed.\n",p->name);
    return(NULL);
  }
  DBG("%s: SK_OPEN: ip opened.\n",p->name);
  return(ipsk);
}

/* 
 * This will later decide, wheter use iface for OSPF or not
 * depending on config
 */
u8
is_good_iface(struct proto *p, struct iface *iface)
{
  if(iface->flags & IF_UP)
  {
    if(!(iface->flags & IF_IGNORE)) return 1;
  }
  return 0;
}

/* Of course, it's NOT true now */
u8
ospf_iface_clasify(struct iface *ifa)
{
  /* FIXME: Latter I'll use config - this is incorrect */
  if((ifa->flags & (IF_MULTIACCESS|IF_MULTICAST))==
    (IF_MULTIACCESS|IF_MULTICAST))
  {
     DBG(" OSPF: Clasifying BCAST.\n");
     return OSPF_IT_BCAST;
  }
  if((ifa->flags & (IF_MULTIACCESS|IF_MULTICAST))==
    IF_MULTIACCESS)
  {
    DBG(" OSPF: Clasifying NBMA.\n");
    return OSPF_IT_NBMA;
  }
  DBG(" OSPF: Clasifying P-T-P.\n");
  return OSPF_IT_PTP;
}

void
hello_timer_hook(timer *timer)
{
  struct ospf_iface *ifa;
  struct ospf_hello_packet *pkt;
  struct ospf_packet *op;
  struct proto *p;
  struct ospf_neighbor *neigh;
  u16 length;
  u32 *pp;
  u8 i;

  ifa=(struct ospf_iface *)timer->data;
  p=(struct proto *)(ifa->proto);
  debug("%s: Hello timer fired on interface %s.\n",
    p->name, ifa->iface->name);
  /* Now we should send a hello packet */
  /* First a common packet header */
  if(ifa->type!=OSPF_IT_NBMA)
  {
    /* Now fill ospf_hello header */
    pkt=(struct ospf_hello_packet *)(ifa->hello_sk->tbuf);
    op=(struct ospf_packet *)pkt;

    fill_ospf_pkt_hdr(ifa, pkt, HELLO);

    pkt->netmask=ipa_mkmask(ifa->iface->addr->pxlen);
    ipa_hton(pkt->netmask);
    pkt->helloint=ntohs(ifa->helloint);
    pkt->options=ifa->options;
    pkt->priority=ifa->priority;
    pkt->deadint=htonl(ifa->deadc*ifa->helloint);
    pkt->dr=htonl(ifa->drid);
    pkt->bdr=htonl(ifa->bdrid);

    /* Fill all neighbors */
    i=0;
    pp=(u32 *)(((u8 *)pkt)+sizeof(struct ospf_hello_packet));
    WALK_LIST (neigh, ifa->neigh_list)
    {
      *(pp+i)=htonl(neigh->rid);
      i++;
    }

    length=sizeof(struct ospf_hello_packet)+i*sizeof(u32);
    op->length=htons(length);

    ospf_pkt_finalize(ifa, op);

    /* And finally send it :-) */
    sk_send(ifa->hello_sk,length);
  }
}

void
wait_timer_hook(timer *timer)
{
  struct ospf_iface *ifa;
  struct proto *p;

  ifa=(struct ospf_iface *)timer->data;
  p=(struct proto *)(ifa->proto);
  debug("%s: Wait timer fired on interface %s.\n",
    p->name, ifa->iface->name);
  ospf_int_sm(ifa, ISM_WAITF);
}

void
ospf_add_timers(struct ospf_iface *ifa, pool *pool)
{
  struct proto *p;

  p=(struct proto *)(ifa->proto);
  /* Add hello timer */
  ifa->hello_timer=tm_new(pool);
  ifa->hello_timer->data=ifa;
  ifa->hello_timer->randomize=0;
  if(ifa->helloint==0) ifa->helloint=HELLOINT_D;
  ifa->hello_timer->hook=hello_timer_hook;
  ifa->hello_timer->recurrent=ifa->helloint;
  DBG("%s: Installing hello timer. (%u)\n", p->name, ifa->helloint);

  ifa->rxmt_timer=tm_new(pool);
  ifa->rxmt_timer->data=ifa;
  ifa->rxmt_timer->randomize=0;
  if(ifa->rxmtint==0) ifa->rxmtint=RXMTINT_D;
  ifa->rxmt_timer->hook=rxmt_timer_hook;
  ifa->rxmt_timer->recurrent=ifa->rxmtint;
  DBG("%s: Installing rxmt timer. (%u)\n", p->name, ifa->rxmtint);

  ifa->wait_timer=tm_new(pool);
  ifa->wait_timer->data=ifa;
  ifa->wait_timer->randomize=0;
  ifa->wait_timer->hook=wait_timer_hook;
  ifa->wait_timer->recurrent=0;
  if(ifa->waitint==0) ifa->waitint= WAIT_DMH*ifa->helloint;
  DBG("%s: Installing wait timer. (%u)\n", p->name, ifa->waitint);
}

void
ospf_iface_default(struct ospf_iface *ifa)
{
  u8 i;

  ifa->area=0; /* FIXME: Read from config */
  ifa->cost=COST_D;
  ifa->rxmtint=RXMTINT_D;
  ifa->iftransdelay=IFTRANSDELAY_D;
  ifa->priority=PRIORITY_D;
  ifa->helloint=HELLOINT_D;
  ifa->deadc=DEADC_D;
  ifa->autype=0;
  for(i=0;i<8;i++) ifa->aukey[i]=0;
  ifa->options=2;
  ifa->drip=ipa_from_u32(0x00000000);
  ifa->drid=0;
  ifa->bdrip=ipa_from_u32(0x00000000);
  ifa->bdrid=0;
  ifa->type=ospf_iface_clasify(ifa->iface);
}

struct ospf_iface*
find_iface(struct proto_ospf *p, struct iface *what)
{
  struct ospf_iface *i;

  WALK_LIST (i, p->iface_list)
    if ((i)->iface == what)
      return i;
  return NULL;
}

void
ospf_if_notify(struct proto *p, unsigned flags, struct iface *iface)
{
  struct ospf_iface *ifa;
  sock *mcsk;

  struct ospf_config *c;
  c=(struct ospf_config *)(p->cf);

  DBG(" OSPF: If notify called\n");
  if (iface->flags & IF_IGNORE)
    return;

  if((flags & IF_CHANGE_UP) && is_good_iface(p, iface))
  {
    debug(" OSPF: using interface %s.\n", iface->name);
    /* FIXME: Latter I'll use config - this is incorrect */
    ifa=mb_alloc(p->pool, sizeof(struct ospf_iface));
    ifa->proto=(struct proto_ospf *)p;
    ifa->iface=iface;
    ospf_iface_default(ifa);
    if(ifa->type!=OSPF_IT_NBMA)
    {
      if((ifa->hello_sk=ospf_open_mc_socket(ifa))==NULL)
      {
        log("%s: Huh? could not open mc socket on interface %s?", p->name,
          iface->name);
	mb_free(ifa);
	log("%s: Ignoring this interface\n", p->name);
	return;
      }

      if((ifa->ip_sk=ospf_open_ip_socket(ifa))==NULL)
      {
        log("%s: Huh? could not open ip socket on interface %s?", p->name,
          iface->name);
	mb_free(ifa);
	log("%s: Ignoring this interface\n", p->name);
	return;
      }

      init_list(&(ifa->neigh_list));
    }
    /* FIXME: This should read config */
    ifa->helloint=0;
    ifa->waitint=0;
    ospf_add_timers(ifa,p->pool);
    add_tail(&((struct proto_ospf *)p)->iface_list, NODE ifa);
    ospf_int_sm(ifa, ISM_UP);
  }

  if(flags & IF_CHANGE_DOWN)
  {
    if((ifa=find_iface((struct proto_ospf *)p, iface))!=NULL)
    {
      debug(" OSPF: killing interface %s.\n", iface->name);
      ospf_int_sm(ifa, ISM_DOWN);
    }
  }

  if(flags & IF_CHANGE_MTU)
  {
    if((ifa=find_iface((struct proto_ospf *)p, iface))!=NULL)
    {
      debug(" OSPF: changing MTU on interface %s.\n", iface->name);
      /* FIXME: change MTU */
    }
  }
}


static int
ospf_start(struct proto *p)
{
  DBG("%s: Start\n",p->name);

  p->if_notify=ospf_if_notify;

  return PS_UP;
}

static void
ospf_dump(struct proto *p)
{
  char areastr[20];
  struct ospf_iface *ifa;
  struct ospf_neighbor *n;
  struct ospf_config *c = (void *) p->cf;

  debug("%s: AreaID: %u\n", p->name, c->area );

  WALK_LIST(ifa, ((struct proto_ospf *)p)->iface_list)
  {
    debug("%s: Interface: %s\n", p->name, ifa->iface->name);
    debug("%s:  state: %u\n", p->name, ifa->state);
    debug("%s:  DR:  %u\n", p->name, ifa->drid);
    debug("%s:  BDR: %u\n", p->name, ifa->bdrid);
    WALK_LIST(n, ifa->neigh_list)
    {
      debug("%s:   neighbor %u in state %u\n", p->name, n->rid, n->state);
    }
  }
}

static struct proto *
ospf_init(struct proto_config *c)
{
  struct proto *p = proto_new(c, sizeof(struct proto_ospf));

  DBG(" OSPF: Init.\n");
  p->neigh_notify = NULL;
  p->if_notify = NULL;
  init_list(&((struct proto_ospf *)p)->iface_list);
  return p;
}

static void
ospf_preconfig(struct protocol *p, struct config *c)
{
  DBG( " OSPF: preconfig\n" );
}

static void
ospf_postconfig(struct proto_config *c)
{
  DBG( " OSPF: postconfig\n" );
}

struct protocol proto_ospf = {
  name:		"OSPF",
  init:		ospf_init,
  dump:		ospf_dump,
  start:	ospf_start,
  preconfig:	ospf_preconfig,
  postconfig:	ospf_postconfig,
};