bgp_nexthop.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

  u_char nexthop_num;
  struct nexthop *nexthop;
  struct bgp_nexthop_cache *bnc;

  s = zlookup->ibuf;
  stream_reset (s);

  nbytes = stream_read (s, zlookup->sock, 2);
  length = stream_getw (s);

  nbytes = stream_read (s, zlookup->sock, length - 2);
  command = stream_getc (s);

  stream_get (&raddr, s, 16);

  metric = stream_getl (s);
  nexthop_num = stream_getc (s);

  if (nexthop_num)
    {
      bnc = bnc_new ();
      bnc->valid = 1;
      bnc->metric = metric;
      bnc->nexthop_num = nexthop_num;

      for (i = 0; i < nexthop_num; i++)
	{
	  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
	  memset (nexthop, 0, sizeof (struct nexthop));
	  nexthop->type = stream_getc (s);
	  switch (nexthop->type)
	    {
	    case ZEBRA_NEXTHOP_IPV6:
	      stream_get (&nexthop->gate.ipv6, s, 16);
	      break;
	    case ZEBRA_NEXTHOP_IPV6_IFINDEX:
	    case ZEBRA_NEXTHOP_IPV6_IFNAME:
	      stream_get (&nexthop->gate.ipv6, s, 16);
	      nexthop->ifindex = stream_getl (s);
	      break;
	    case ZEBRA_NEXTHOP_IFINDEX:
	    case ZEBRA_NEXTHOP_IFNAME:
	      nexthop->ifindex = stream_getl (s);
	      break;
	    }
	  bnc_nexthop_add (bnc, nexthop);
	}
    }
  else
    return NULL;

  return bnc;
}

struct bgp_nexthop_cache *
zlookup_query_ipv6 (struct in6_addr *addr)
{
  int ret;
  struct stream *s;

  /* Check socket. */
  if (zlookup->sock < 0)
    return NULL;

  s = zlookup->obuf;
  stream_reset (s);
  stream_putw (s, 19);
  stream_putc (s, ZEBRA_IPV6_NEXTHOP_LOOKUP);
  stream_put (s, addr, 16);

  ret = writen (zlookup->sock, s->data, 19);
  if (ret < 0)
    {
      zlog_err ("can't write to zlookup->sock");
      close (zlookup->sock);
      zlookup->sock = -1;
      return NULL;
    }
  if (ret == 0)
    {
      zlog_err ("zlookup->sock connection closed");
      close (zlookup->sock);
      zlookup->sock = -1;
      return NULL;
    }

  return zlookup_read_ipv6 ();
}
#endif /* HAVE_IPV6 */

int
bgp_import_check (struct prefix *p, u_int32_t *igpmetric, struct in_addr *igpnexthop)
{
  struct stream *s;
  int ret;
  u_int16_t length;
  u_char command;
  int nbytes;
  struct in_addr addr;
  struct in_addr nexthop;
  u_int32_t metric = 0;
  u_char nexthop_num;
  u_char nexthop_type;

  /* If lookup connection is not available return valid. */
  if (zlookup->sock < 0)
    {
      if (igpmetric)
	*igpmetric = 0;
      return 1;
    }

  /* Send query to the lookup connection */
  s = zlookup->obuf;
  stream_reset (s);
  stream_putw (s, 8);
  stream_putc (s, ZEBRA_IPV4_IMPORT_LOOKUP);
  stream_putc (s, p->prefixlen);
  stream_put_in_addr (s, &p->u.prefix4);

  /* Write the packet. */
  ret = writen (zlookup->sock, s->data, 8);

  if (ret < 0)
    {
      zlog_err ("can't write to zlookup->sock");
      close (zlookup->sock);
      zlookup->sock = -1;
      return 1;
    }
  if (ret == 0)
    {
      zlog_err ("zlookup->sock connection closed");
      close (zlookup->sock);
      zlookup->sock = -1;
      return 1;
    }

  /* Get result. */
  stream_reset (s);

  /* Fetch length. */
  nbytes = stream_read (s, zlookup->sock, 2);
  length = stream_getw (s);

  /* Fetch whole data. */
  nbytes = stream_read (s, zlookup->sock, length - 2);
  command = stream_getc (s);
  addr.s_addr = stream_get_ipv4 (s);
  metric = stream_getl (s);
  nexthop_num = stream_getc (s);

  /* Set IGP metric value. */
  if (igpmetric)
    *igpmetric = metric;

  /* If there is nexthop then this is active route. */
  if (nexthop_num)
    {
      nexthop.s_addr = 0;
      nexthop_type = stream_getc (s);
      if (nexthop_type == ZEBRA_NEXTHOP_IPV4)
	{
	  nexthop.s_addr = stream_get_ipv4 (s);
	  if (igpnexthop)
	    *igpnexthop = nexthop;
	}
      else
	*igpnexthop = nexthop;

      return 1;
    }
  else
    return 0;
}

/* Scan all configured BGP route then check the route exists in IGP or
   not. */
int
bgp_import (struct thread *t)
{
  struct bgp_master *bm;
  struct bgp *bgp;
  struct bgp_node *rn;
  struct bgp_static *bgp_static;
  struct listnode *nn;
  int valid;
  u_int32_t metric;
  struct in_addr nexthop;
  afi_t afi;
  safi_t safi;

  bgp_import_thread = 
    thread_add_timer (master, bgp_import, NULL, bgp_import_interval);

  bm = bgp_get_master ();
  if (! bm)
    return 0;

  LIST_LOOP (bm->bgp, bgp, nn)
    {
      for (afi = AFI_IP; afi < AFI_MAX; afi++)
	for (safi = SAFI_UNICAST; safi < SAFI_MPLS_VPN; safi++)
	  for (rn = bgp_table_top (bgp->route[afi][safi]); rn;
	       rn = bgp_route_next (rn))
	    if ((bgp_static = rn->info) != NULL)
	      {
		if (bgp_static->backdoor)
		  continue;

		valid = bgp_static->valid;
		metric = bgp_static->igpmetric;
		nexthop = bgp_static->igpnexthop;

		if (bgp_flag_check (bgp, BGP_FLAG_IMPORT_CHECK)
		    && afi == AFI_IP && safi == SAFI_UNICAST)
		  bgp_static->valid = bgp_import_check (&rn->p, &bgp_static->igpmetric,
						        &bgp_static->igpnexthop);
		else
		  {
		    bgp_static->valid = 1;
		    bgp_static->igpmetric = 0;
		    bgp_static->igpnexthop.s_addr = 0;
		  }

		if (bgp_static->valid != valid)
		  {
		    if (bgp_static->valid)
		      bgp_static_update (bgp, &rn->p, bgp_static, afi, safi);
		    else
		      bgp_static_withdraw (bgp, &rn->p, afi, safi);
		  }
		else if (bgp_static->valid)
		  {
		    if (bgp_static->igpmetric != metric
			|| bgp_static->igpnexthop.s_addr != nexthop.s_addr
			|| bgp_static->rmap.name)
		      bgp_static_update (bgp, &rn->p, bgp_static, afi, safi);
		  }
	      }
    }
  return 0;
}

/* Connect to zebra for nexthop lookup. */
int
zlookup_connect (struct thread *t)
{
  struct zclient *zlookup;

  zlookup = THREAD_ARG (t);
  zlookup->t_connect = NULL;

  if (zlookup->sock != -1)
    return 0;

#ifdef HAVE_TCP_ZEBRA
  zlookup->sock = zclient_socket ();
#else
  zlookup->sock = zclient_socket_un (ZEBRA_SERV_PATH);
#endif /* HAVE_TCP_ZEBRA */
  if (zlookup->sock < 0)
    return -1;

  return 0;
}

/* Check specified multiaccess next-hop. */
int
bgp_multiaccess_check_v4 (struct in_addr nexthop, char *peer)
{
  struct bgp_node *rn1;
  struct bgp_node *rn2;
  struct prefix p1;
  struct prefix p2;
  struct in_addr addr;
  int ret;

  ret = inet_aton (peer, &addr);
  if (! ret)
    return 0;

  memset (&p1, 0, sizeof (struct prefix));
  p1.family = AF_INET;
  p1.prefixlen = IPV4_MAX_BITLEN;
  p1.u.prefix4 = nexthop;
  memset (&p2, 0, sizeof (struct prefix));
  p2.family = AF_INET;
  p2.prefixlen = IPV4_MAX_BITLEN;
  p2.u.prefix4 = addr;

  /* If bgp scan is not enabled, return invalid. */
  if (zlookup->sock < 0)
    return 0;

  rn1 = bgp_node_match (bgp_connected_ipv4, &p1);
  if (! rn1)
    return 0;
  
  rn2 = bgp_node_match (bgp_connected_ipv4, &p2);
  if (! rn2)
    return 0;

  if (rn1 == rn2)
    return 1;

  return 0;
}

DEFUN (bgp_scan_time,
       bgp_scan_time_cmd,
       "bgp scan-time <5-60>",
       "BGP specific commands\n"
       "Configure background scanner interval\n"
       "Scanner interval (seconds)\n")
{
  bgp_scan_interval = atoi (argv[0]);

  if (bgp_scan_thread)
    {
      thread_cancel (bgp_scan_thread);
      bgp_scan_thread = 
	thread_add_timer (master, bgp_scan, NULL, bgp_scan_interval);
    }

  return CMD_SUCCESS;
}

DEFUN (no_bgp_scan_time,
       no_bgp_scan_time_cmd,
       "no bgp scan-time",
       NO_STR
       "BGP specific commands\n"
       "Configure background scanner interval\n")
{
  bgp_scan_interval = BGP_SCAN_INTERVAL_DEFAULT;

  if (bgp_scan_thread)
    {
      thread_cancel (bgp_scan_thread);
      bgp_scan_thread = 
	thread_add_timer (master, bgp_scan, NULL, bgp_scan_interval);
    }

  return CMD_SUCCESS;
}

ALIAS (no_bgp_scan_time,
       no_bgp_scan_time_val_cmd,
       "no bgp scan-time <5-60>",
       NO_STR
       "BGP specific commands\n"
       "Configure background scanner interval\n"
       "Scanner interval (seconds)\n");

DEFUN (show_ip_bgp_scan,
       show_ip_bgp_scan_cmd,
       "show ip bgp scan",
       SHOW_STR
       IP_STR
       BGP_STR
       "BGP scan status\n")
{
  struct bgp_node *rn;
  struct bgp_nexthop_cache *bnc;

  if (bgp_scan_thread)
    vty_out (vty, "BGP scan is running%s", VTY_NEWLINE);
  else
    vty_out (vty, "BGP scan is not running%s", VTY_NEWLINE);
  vty_out (vty, "BGP scan interval is %d%s", bgp_scan_interval, VTY_NEWLINE);

  vty_out (vty, "Current BGP nexthop cache:%s", VTY_NEWLINE);
  for (rn = bgp_table_top (bgp_nexthop_cache_ipv4); rn; rn = bgp_route_next (rn))
    if ((bnc = rn->info) != NULL)
      {
	if (bnc->valid)
	  vty_out (vty, " %s valid [IGP metric %d]%s",
		   inet_ntoa (rn->p.u.prefix4), bnc->metric, VTY_NEWLINE);
	else
	  vty_out (vty, " %s invalid%s",
		   inet_ntoa (rn->p.u.prefix4), VTY_NEWLINE);
      }

#ifdef HAVE_IPV6
  {
    char buf[BUFSIZ];
    for (rn = bgp_table_top (bgp_nexthop_cache_ipv6); rn; rn = bgp_route_next (rn))
      if ((bnc = rn->info) != NULL)
	{
	  if (bnc->valid)
	    vty_out (vty, " %s valid [IGP metric %d]%s",
		     inet_ntop (AF_INET6, &rn->p.u.prefix6, buf, BUFSIZ),
		     bnc->metric, VTY_NEWLINE);
	  else
	    vty_out (vty, " %s invalid%s",
		     inet_ntop (AF_INET6, &rn->p.u.prefix6, buf, BUFSIZ),
		     VTY_NEWLINE);
	}
  }
#endif /* HAVE_IPV6 */

  vty_out (vty, "BGP connected route:%s", VTY_NEWLINE);
  for (rn = bgp_table_top (bgp_connected_ipv4); rn; rn = bgp_route_next (rn))
    if (rn->info != NULL)
      vty_out (vty, " %s/%d%s", inet_ntoa (rn->p.u.prefix4), rn->p.prefixlen,
	       VTY_NEWLINE);

#ifdef HAVE_IPV6
  {
    char buf[BUFSIZ];

    for (rn = bgp_table_top (bgp_connected_ipv6); rn; rn = bgp_route_next (rn))
      if (rn->info != NULL)
	vty_out (vty, " %s/%d%s",
		 inet_ntop (AF_INET6, &rn->p.u.prefix6, buf, BUFSIZ),
		 rn->p.prefixlen,
		 VTY_NEWLINE);
  }
#endif /* HAVE_IPV6 */

  return CMD_SUCCESS;
}

int
bgp_config_write_scan_time (struct vty *vty)
{
  if (bgp_scan_interval != BGP_SCAN_INTERVAL_DEFAULT)
    vty_out (vty, " bgp scan-time %d%s", bgp_scan_interval, VTY_NEWLINE);
  return CMD_SUCCESS;
}

void
bgp_scan_init ()
{
  zlookup = zclient_new ();
  zlookup->sock = -1;
  zlookup->ibuf = stream_new (ZEBRA_MAX_PACKET_SIZ);
  zlookup->obuf = stream_new (ZEBRA_MAX_PACKET_SIZ);
  zlookup->t_connect = thread_add_event (master, zlookup_connect, zlookup, 0);

  bgp_scan_interval = BGP_SCAN_INTERVAL_DEFAULT;
  bgp_import_interval = BGP_IMPORT_INTERVAL_DEFAULT;

  cache1 = bgp_table_init ();
  cache2 = bgp_table_init ();
  bgp_nexthop_cache_ipv4 = cache1;

  bgp_connected_ipv4 = bgp_table_init ();

#ifdef HAVE_IPV6
  cache6_1 = bgp_table_init ();
  cache6_2 = bgp_table_init ();
  bgp_nexthop_cache_ipv6 = cache6_1;
  bgp_connected_ipv6 = bgp_table_init ();
#endif /* HAVE_IPV6 */

  /* Make BGP scan thread. */
  bgp_scan_thread = thread_add_timer (master, bgp_scan, NULL, bgp_scan_interval);
  /* Make BGP import there. */
  bgp_import_thread = thread_add_timer (master, bgp_import, NULL, 0);

  install_element (BGP_NODE, &bgp_scan_time_cmd);
  install_element (BGP_NODE, &no_bgp_scan_time_cmd);
  install_element (BGP_NODE, &no_bgp_scan_time_val_cmd);
  install_element (VIEW_NODE, &show_ip_bgp_scan_cmd);
  install_element (ENABLE_NODE, &show_ip_bgp_scan_cmd);
}