packet.c 5.68 KB
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/*
 *	BIRD -- OSPF
 *
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 *	(c) 1999 - 2000 Ondrej Filip <feela@network.cz>
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 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "ospf.h"

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);
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  pkt->areaid=htonl(ifa->an);
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  pkt->autype=htons(ifa->autype);
  pkt->checksum=0;
}

void
ospf_tx_authenticate(struct ospf_iface *ifa, struct ospf_packet *pkt)
{
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  int i;
  pkt->autype=ifa->autype;
  memcpy(pkt->authetication, ifa->aukey, 8);
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  return;
}

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int
ospf_rx_authenticate(struct ospf_iface *ifa, struct ospf_packet *pkt)
{
  int i;
  if(pkt->autype!=ifa->autype) return 0;
  if(ifa->autype==AU_NONE) return 1;
  if(ifa->autype==AU_SIMPLE)
  {
    for(i=0;i<8;i++)
    {
      if(pkt->authetication[i]!=ifa->aukey[i]) return 0;
    }
    return 1;
  }
  return 0;
}

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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);
}

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/**
 * ospf_rx_hook
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 * @sk: socket we received the packet. Its ignored.
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 * @size: size of the packet
 *
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 * This is the entry point for messages from neighbors. Many checks (like
 * authentication, checksums, size) are done before the packet is passed to
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 * non generic functions.
 */
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int
ospf_rx_hook(sock *sk, int size)
{
#ifndef IPV6
  struct ospf_packet *ps;
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  struct ospf_iface *ifa=(struct ospf_iface *)(sk->data);
  struct proto *p=(struct proto *)(ifa->proto);
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  int i;
  u8 *pu8;

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  if(ifa->stub) return(1);

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  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);
  }

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  if((ntohs(ps->length)!=size)||(size!=(4*(size/4))))
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  {
    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);
  }

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  if(!ospf_rx_authenticate(ifa,ps))
  {
    log("%s: Bad OSPF packet received: bad password", p->name);
    return(1);
  }

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  if(ntohl(ps->areaid)!=ifa->an)
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  {
    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)
  {
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    log("%s: Bad OSPF packet received: received my own router ID!", p->name);
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    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);
  }
  
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  /* Dump packet 
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  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]);
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  DBG("%s: received size: %u\n",p->name,size);
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  */
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  switch(ps->type)
  {
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    case HELLO_P:
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      DBG("%s: Hello received.\n", p->name);
      ospf_hello_rx((struct ospf_hello_packet *)ps, p, ifa, size, sk->faddr);
      break;
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    case DBDES_P:
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      DBG("%s: Database description received.\n", p->name);
      ospf_dbdes_rx((struct ospf_dbdes_packet *)ps, p, ifa, size);
      break;
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    case LSREQ_P:
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      DBG("%s: Link state request received.\n", p->name);
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      ospf_lsreq_rx((struct ospf_lsreq_packet *)ps, p, ifa, size);
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      break;
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    case LSUPD_P:
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      DBG("%s: Link state update received.\n", p->name);
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      ospf_lsupd_rx((struct ospf_lsupd_packet *)ps, p, ifa, size);
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      break;
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    case LSACK_P:
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      DBG("%s: Link state ack received.\n", p->name);
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      ospf_lsack_rx((struct ospf_lsack_packet *)ps, p, ifa, size);
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      break;
    default:
      log("%s: Bad packet received: wrong type %u", p->name, ps->type);
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      log("%s: Discarding\n",p->name);
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      return(1);
  };
#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);
}

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void
sk_send_to_agt(sock *sk, u16 len, struct ospf_iface *ifa, u8 state)
{
  struct ospf_neighbor *n;

  WALK_LIST(NODE n,ifa->neigh_list)
    if(n->state>=state)
      sk_send_to(sk, len, n->ip, OSPF_PROTO);
}                                                                       
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void
sk_send_to_bdr(sock *sk, u16 len, struct ospf_iface *ifa)
{
  struct ospf_neighbor *n;

  if(ipa_compare(ifa->drip,ipa_from_u32(0))!=0)
    sk_send_to(sk, len, ifa->drip, OSPF_PROTO);
  if(ipa_compare(ifa->bdrip,ipa_from_u32(0))!=0)
    sk_send_to(sk, len, ifa->bdrip, OSPF_PROTO);
}