isisd/isis_tlv.c

/*
 * IS-IS Rout(e)ing protocol - isis_tlv.c
 *                             IS-IS TLV related routines
 *
 * Copyright (C) 2001,2002   Sampo Saaristo
 *                           Tampere University of Technology      
 *                           Institute of Communications Engineering
 *
 * This program is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU General Public Licenseas published by the Free 
 * Software Foundation; either version 2 of the License, or (at your option) 
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,but WITHOUT 
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for 
 * more details.

 * You should have received a copy of the GNU General Public License along 
 * with this program; if not, write to the Free Software Foundation, Inc., 
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <zebra.h>

#include "log.h"
#include "linklist.h"
#include "stream.h"
#include "memory.h"
#include "prefix.h"
#include "vty.h"
#include "if.h"

#include "isisd/dict.h"
#include "isisd/isis_constants.h"
#include "isisd/isis_common.h"
#include "isisd/isis_flags.h"
#include "isisd/isis_circuit.h"
#include "isisd/isis_tlv.h"
#include "isisd/isisd.h"
#include "isisd/isis_dynhn.h"
#include "isisd/isis_misc.h"
#include "isisd/isis_pdu.h"
#include "isisd/isis_lsp.h"

extern struct isis *isis;

void
free_tlv (void *val)
{
    XFREE (MTYPE_ISIS_TLV, val);
    
    return;
}

/*
 * Called after parsing of a PDU. There shouldn't be any tlv's left, so this
 * is only a caution to avoid memory leaks
 */
void 
free_tlvs (struct tlvs *tlvs)
{
  if (tlvs->area_addrs) {
    list_delete (tlvs->area_addrs);
  }
  if (tlvs->is_neighs) {
    list_delete (tlvs->is_neighs);
  }
  if (tlvs->te_is_neighs) {
    list_delete (tlvs->te_is_neighs);
  }
  if (tlvs->es_neighs) {
    list_delete (tlvs->es_neighs);
  }
  if (tlvs->lsp_entries) {
    list_delete (tlvs->lsp_entries);
  }  
  if (tlvs->lan_neighs) {
    list_delete (tlvs->lan_neighs);
  }
  if (tlvs->prefix_neighs) {
    list_delete (tlvs->prefix_neighs);
  }
  if (tlvs->ipv4_addrs) {
    list_delete (tlvs->ipv4_addrs);
  }
  if (tlvs->ipv4_int_reachs) {
    list_delete (tlvs->ipv4_int_reachs);
  }
  if (tlvs->ipv4_ext_reachs) {
    list_delete (tlvs->ipv4_ext_reachs);
  }
  if (tlvs->te_ipv4_reachs) {
    list_delete (tlvs->te_ipv4_reachs);
  }
#ifdef HAVE_IPV6
  if (tlvs->ipv6_addrs) {
    list_delete (tlvs->ipv6_addrs);
  }
  if (tlvs->ipv6_reachs) {
    list_delete (tlvs->ipv6_reachs);
  }
#endif /* HAVE_IPV6 */
  return;
}

/*
 * Parses the tlvs found in the variant length part of the PDU.
 * Caller tells with flags in "expected" which TLV's it is interested in.
 */
int 
parse_tlvs (char *areatag, u_char *stream, int size, u_int32_t *expected, 
	    u_int32_t *found, struct tlvs *tlvs)
{
  u_char                          type, length;
  struct lan_neigh                    *lan_nei;
  struct area_addr                  *area_addr;
  struct is_neigh                      *is_nei;
  struct te_is_neigh                *te_is_nei;
  struct es_neigh                      *es_nei;
  struct lsp_entry                  *lsp_entry;
  struct in_addr                    *ipv4_addr;
  struct ipv4_reachability         *ipv4_reach;
  struct te_ipv4_reachability   *te_ipv4_reach;
#ifdef HAVE_IPV6
  struct in6_addr                   *ipv6_addr;
  struct ipv6_reachability         *ipv6_reach;
  int                            prefix_octets;
#endif /* HAVE_IPV6 */
  u_char                               virtual;
  int              value_len, retval = ISIS_OK;
  u_char                   *pnt = stream;

  *found = 0;
  memset (tlvs, 0, sizeof (struct tlvs));
  
  while (pnt < stream + size - 2) {
    type = *pnt;
    length = *(pnt+1);
    pnt += 2;
    value_len = 0;
    if ( pnt + length > stream + size ) {
      zlog_warn ("ISIS-TLV (%s): TLV (type %d, length %d) exceeds packet "
		 "boundaries", areatag, type, length);
      retval = ISIS_WARNING;
      break;
    }
    switch (type) {
    case AREA_ADDRESSES:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Address Length                         | 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                         Area Address                          | 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * :                                                               :
       */
      *found |= TLVFLAG_AREA_ADDRS;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("TLV Area Adresses len %d", length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_AREA_ADDRS) {
        while (length > value_len) {
          area_addr = (struct area_addr*)pnt;
          value_len += area_addr->addr_len + 1;
          pnt +=  area_addr->addr_len + 1;
          if (!tlvs->area_addrs) tlvs->area_addrs = list_new ();
          listnode_add (tlvs->area_addrs, area_addr);
        }
      } else {
        pnt += length;
      }
      break;

    case IS_NEIGHBOURS:
      *found |= TLVFLAG_IS_NEIGHS;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IS Neighbours length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (TLVFLAG_IS_NEIGHS & *expected) {
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Virtual Flag                           | 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       */
        virtual = *pnt; /* FIXME: what is the use for this? */
        pnt++;
        value_len ++;
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   0   |  I/E  |               Default Metric                  | 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Delay Metric                    |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Expense Metric                  |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Error Metric                    |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Neighbour ID                           |
       * +---------------------------------------------------------------+
       * :                                                               :
       */
        while (length > value_len) {
          is_nei = (struct is_neigh*)pnt;
          value_len += 4 + ISIS_SYS_ID_LEN + 1;
          pnt += 4 + ISIS_SYS_ID_LEN + 1;
          if (!tlvs->is_neighs) tlvs->is_neighs = list_new ();
          listnode_add (tlvs->is_neighs, is_nei);
        }
      } else {
        pnt += length;
      }
      break;

    case TE_IS_NEIGHBOURS:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Neighbour ID                           | 7
       * +---------------------------------------------------------------+
       * |                        TE Metric                              | 3
       * +---------------------------------------------------------------+
       * |                        SubTLVs Length                         | 1
       * +---------------------------------------------------------------+
       * :                                                               :
       */
      *found |= TLVFLAG_TE_IS_NEIGHS;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): Extended IS Neighbours length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (TLVFLAG_TE_IS_NEIGHS & *expected) {
        while (length > value_len) {
          te_is_nei = (struct te_is_neigh*)pnt;
          value_len += 11;
          pnt += 11;
          /* FIXME - subtlvs are handled here, for now we skip */
          value_len += te_is_nei->sub_tlvs_length;
          pnt += te_is_nei->sub_tlvs_length;


          if (!tlvs->te_is_neighs) tlvs->te_is_neighs = list_new ();
          listnode_add (tlvs->te_is_neighs, te_is_nei);
        }
      } else {
        pnt += length;
      }
      break;

    case ES_NEIGHBOURS: 
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   0   |  I/E  |               Default Metric                  | 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Delay Metric                    |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Expense Metric                  |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Error Metric                    |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Neighbour ID                           |
       * +---------------------------------------------------------------+
       * |                        Neighbour ID                           |
       * +---------------------------------------------------------------+
       * :                                                               :
       */
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): ES Neighbours length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      *found |= TLVFLAG_ES_NEIGHS;
      if (*expected & TLVFLAG_ES_NEIGHS) {
        es_nei = (struct es_neigh*)pnt;
        value_len += 4;
        pnt += 4;
        while (length > value_len) {
        /* FIXME FIXME FIXME - add to the list */
	/*          sys_id->id = pnt;*/
          value_len += ISIS_SYS_ID_LEN;
          pnt += ISIS_SYS_ID_LEN;
        /*  if (!es_nei->neigh_ids) es_nei->neigh_ids = sysid;*/
        }
        if (!tlvs->es_neighs) tlvs->es_neighs = list_new ();
        listnode_add (tlvs->es_neighs, es_nei);
      } else {
        pnt += length;
      }
      break;

    case LAN_NEIGHBOURS:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        LAN Address                            | 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * :                                                               :
       */
      *found |= TLVFLAG_LAN_NEIGHS;
      #ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): LAN Neigbours length %d",
		 areatag,
		 length);
      #endif /* EXTREME_TLV_DEBUG */
      if (TLVFLAG_LAN_NEIGHS & *expected) {
        while (length > value_len) {
          lan_nei = (struct lan_neigh*)pnt;
          if (!tlvs->lan_neighs) tlvs->lan_neighs = list_new ();
          listnode_add (tlvs->lan_neighs, lan_nei);
          value_len += ETH_ALEN;
          pnt += ETH_ALEN;
        }
      } else {
        pnt += length;
      }
      break;

    case PADDING:
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("TLV padding %d", length);
#endif /* EXTREME_TLV_DEBUG */
      pnt += length;
      break;

    case LSP_ENTRIES:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                     Remaining Lifetime                        | 2
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                         LSP ID                                | id+2
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                   LSP Sequence Number                         | 4
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Checksum                               | 2
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       */
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("LSP Entries length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      *found |= TLVFLAG_LSP_ENTRIES;
      if (TLVFLAG_LSP_ENTRIES & *expected) {
        while (length > value_len) {
          lsp_entry = (struct lsp_entry*)pnt;
          value_len += 10 + ISIS_SYS_ID_LEN;
          pnt +=  10 + ISIS_SYS_ID_LEN;
          if (!tlvs->lsp_entries) tlvs->lsp_entries = list_new ();
          listnode_add (tlvs->lsp_entries, lsp_entry);
        }
      } else {
        pnt += length;
      }
      break;

    case CHECKSUM:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                   16 bit fletcher CHECKSUM                    |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * :                                                               :
       */
      *found |= TLVFLAG_CHECKSUM;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): Checksum length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_CHECKSUM) {
        tlvs->checksum = (struct checksum*)pnt;
      }
      pnt += length;
      break;

    case PROTOCOLS_SUPPORTED:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                       NLPID                                   |
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * :                                                               :
       */
      *found |= TLVFLAG_NLPID;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): Protocols Supported length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_NLPID) {
        tlvs->nlpids = (struct nlpids*)(pnt-1);
      }
      pnt += length;
      break;

    case IPV4_ADDR:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * +                 IP version 4 address                          + 4
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * :                                                               :
       */
      *found |= TLVFLAG_IPV4_ADDR;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IPv4 Address length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_IPV4_ADDR) {
        while (length > value_len) {
          ipv4_addr = (struct in_addr*)pnt;
	  zlog_info ("ISIS-TLV (%s) : IP ADDR %s, pnt %p", areatag, 
		     inet_ntoa (*ipv4_addr), pnt);
          if (!tlvs->ipv4_addrs) tlvs->ipv4_addrs = list_new();
          listnode_add (tlvs->ipv4_addrs, ipv4_addr);
          value_len += 4;
          pnt += 4;
        }
      } else {
        pnt += length;
      }
      break;

    case AUTH_INFO:
      *found |= TLVFLAG_AUTH_INFO;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IS-IS Authentication Information",
		 areatag);
#endif
      if (*expected & TLVFLAG_AUTH_INFO) {
	tlvs->auth_info.type = *pnt;
	pnt++;
	memcpy (tlvs->auth_info.passwd, pnt, length - 1);
	pnt += length - 1;
      }
      else {
	pnt += length;
      }
      break;

    case DYNAMIC_HOSTNAME:
      *found |= TLVFLAG_DYN_HOSTNAME;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): Dynamic Hostname length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_DYN_HOSTNAME) {
	/* the length is also included in the pointed struct */
        tlvs->hostname = (struct hostname*)(pnt - 1); 
      }
      pnt += length;
      break;

    case TE_ROUTER_ID:
      /* +---------------------------------------------------------------+
       * +                         Router ID                             + 4
       * +---------------------------------------------------------------+
       */
      *found |= TLVFLAG_TE_ROUTER_ID;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): TE Router ID %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_TE_ROUTER_ID) {
        tlvs->router_id = (struct te_router_id*)(pnt);
      }
      pnt += length;
      break;

    case IPV4_INT_REACHABILITY:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   0   |  I/E  |               Default Metric                  | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Delay Metric                    | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Expense Metric                  | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Error Metric                    | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        ip address                             | 4
       * +---------------------------------------------------------------+
       * |                        address mask                           | 4
       * +---------------------------------------------------------------+
       * :                                                               :
       */
      *found |= TLVFLAG_IPV4_INT_REACHABILITY;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IPv4 internal Reachability length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_IPV4_INT_REACHABILITY) {
        while (length > value_len) {
          ipv4_reach = (struct ipv4_reachability*)pnt;
          if (!tlvs->ipv4_int_reachs) tlvs->ipv4_int_reachs = list_new();
          listnode_add (tlvs->ipv4_int_reachs, ipv4_reach);
          value_len += 12;
          pnt += 12;
        }
      }
      else {
        pnt += length;
      }
      break;

    case IPV4_EXT_REACHABILITY:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   0   |  I/E  |               Default Metric                  | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Delay Metric                    | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Expense Metric                  | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |   S   |  I/E  |               Error Metric                    | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        ip address                             | 4
       * +---------------------------------------------------------------+
       * |                        address mask                           | 4
       * +---------------------------------------------------------------+
       * :                                                               :
       */
      *found |= TLVFLAG_IPV4_EXT_REACHABILITY;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IPv4 external Reachability length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_IPV4_EXT_REACHABILITY) {
        while (length > value_len) {
          ipv4_reach = (struct ipv4_reachability*)pnt;
          if (!tlvs->ipv4_ext_reachs) 
            tlvs->ipv4_ext_reachs = list_new();
          listnode_add (tlvs->ipv4_ext_reachs, ipv4_reach);
          value_len += 12;
          pnt += 12;
        }
      }
      else {
        pnt += length;
      }
      break;

    case TE_IPV4_REACHABILITY:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        TE Metric                              | 4
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |  U/D  | sTLV? |               Prefix Mask Len                 | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                           Prefix                              | 0-4
       * +---------------------------------------------------------------+
       * |                         sub tlvs                              |
       * +---------------------------------------------------------------+
       * :                                                               :
       */
      *found |= TLVFLAG_TE_IPV4_REACHABILITY;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IPv4 extended Reachability length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_TE_IPV4_REACHABILITY) {
        while (length > value_len) {
          te_ipv4_reach = (struct te_ipv4_reachability*)pnt;
          if (!tlvs->te_ipv4_reachs) tlvs->te_ipv4_reachs = list_new();
          listnode_add (tlvs->te_ipv4_reachs, te_ipv4_reach);
          /* this trickery is permitable since no subtlvs are defined */
          value_len += 5 + ((te_ipv4_reach->control & 0x3F) ? 
                           ((((te_ipv4_reach->control & 0x3F)-1)>>3)+1) : 0);
          pnt +=  5 + ((te_ipv4_reach->control & 0x3F) ? 
                      ((((te_ipv4_reach->control & 0x3F)-1)>>3)+1) : 0);
        }
      }
      else {
        pnt += length;
      }
      break;

#ifdef  HAVE_IPV6
    case IPV6_ADDR:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * +                 IP version 6 address                          + 16
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * :                                                               :
       */
      *found |= TLVFLAG_IPV6_ADDR;
#ifdef EXTREME_TLV_DEBUG
      zlog_info ("ISIS-TLV (%s): IPv6 Address length %d",
		 areatag,
		 length);
#endif /* EXTREME_TLV_DEBUG */
      if (*expected & TLVFLAG_IPV6_ADDR) {
        while (length > value_len) {
          ipv6_addr = (struct in6_addr*)pnt;
          if (!tlvs->ipv6_addrs) tlvs->ipv6_addrs = list_new();
          listnode_add (tlvs->ipv6_addrs, ipv6_addr);
          value_len += 16;
          pnt += 16;
        }
      } else {
        pnt += length;
      }
      break;

    case IPV6_REACHABILITY:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                 Default Metric                                | 4 
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                        Control Informantion                   |
       * +---------------------------------------------------------------+
       * |                        IPv6 Prefix Length                     |--+
       * +---------------------------------------------------------------+  |
       * |                        IPv6 Prefix                            |<-+
       * +---------------------------------------------------------------+
       */
      *found |= TLVFLAG_IPV6_REACHABILITY;
      if (*expected & TLVFLAG_IPV6_REACHABILITY) {
        while (length > value_len) {
          ipv6_reach = (struct ipv6_reachability*)pnt;
          prefix_octets = ((ipv6_reach->prefix_len + 7) / 8);
          value_len += prefix_octets + 6;
          pnt +=  prefix_octets + 6;
          /* FIXME: sub-tlvs */
          if (!tlvs->ipv6_reachs) tlvs->ipv6_reachs = list_new();
          listnode_add (tlvs->ipv6_reachs, ipv6_reach);
        }
      } else {
        pnt += length;
      }
      break;
#endif /* HAVE_IPV6 */

    case WAY3_HELLO:
      /* +---------------------------------------------------------------+
       * |                  Adjacency state                              | 1
       * +---------------------------------------------------------------+
       * |                  Extended Local Circuit ID                    | 4
       * +---------------------------------------------------------------+
       * |                  Neighbor System ID (If known)                | 0-8
       *                                      (probably 6)
       * +---------------------------------------------------------------+
       * |                  Neighbor Local Circuit ID (If known)         | 4
       * +---------------------------------------------------------------+
       */
      *found |= TLVFLAG_3WAY_HELLO;
      if (*expected & TLVFLAG_3WAY_HELLO) {
        while (length > value_len) {
        /* FIXME: make this work */
/*           Adjacency State (one octet):
              0 = Up
              1 = Initializing
              2 = Down
            Extended Local Circuit ID (four octets)
            Neighbor System ID if known (zero to eight octets)
            Neighbor Extended Local Circuit ID (four octets, if Neighbor
              System ID is present) */
          pnt += length;
        }
      } else {
        pnt += length;
      }

      break;
    case GRACEFUL_RESTART:
      /* +-------+-------+-------+-------+-------+-------+-------+-------+
       * |         Reserved                      |  SA   |  RA   |  RR   | 1
       * +-------+-------+-------+-------+-------+-------+-------+-------+
       * |                          Remaining Time                       | 2
       * +---------------------------------------------------------------+
       * |                Restarting Neighbor ID (If known)              | 0-8
       * +---------------------------------------------------------------+
       */
      *found |= TLVFLAG_GRACEFUL_RESTART;
      if (*expected & TLVFLAG_GRACEFUL_RESTART) {
        /* FIXME: make this work */
      }
      pnt += length;
      break;

    default:
      zlog_warn ("ISIS-TLV (%s): unsupported TLV type %d, length %d",
		 areatag,
		 type,
		 length);

      retval = ISIS_WARNING;
      pnt += length;
      break;
    }
  }
  
  return retval;
}

int
add_tlv (u_char tag, u_char len, u_char *value, struct stream *stream)
{

  if (STREAM_SIZE (stream) - stream_get_putp (stream)  < len + 2) {
    zlog_warn ("No room for TLV of type %d", tag);
    return ISIS_WARNING;
  }

  stream_putc (stream, tag);  /* TAG */
  stream_putc (stream, len);  /* LENGTH */
  stream_put (stream, value, (int)len); /* VALUE */

#ifdef EXTREME_DEBUG
  zlog_info ("Added TLV %d len %d", tag, len);
#endif /* EXTREME DEBUG */
  return ISIS_OK;
}


int
tlv_add_area_addrs (struct list *area_addrs, struct stream *stream) 
{
  struct listnode *node;
  struct area_addr *area_addr;

  u_char value [255];
  u_char *pos = value;
  
  for (node = listhead (area_addrs); node; nextnode (node)) { 
    area_addr = getdata (node);
    if (pos - value + area_addr->addr_len > 255)
      goto err;
    *pos = area_addr->addr_len;
    pos ++;
    memcpy (pos, area_addr->area_addr, (int)area_addr->addr_len);
    pos += area_addr->addr_len;
  }
  
  return add_tlv (AREA_ADDRESSES, pos - value, value, stream);

 err:
  zlog_warn ("tlv_add_area_addrs(): TLV longer than 255");
  return ISIS_WARNING;
}

int tlv_add_is_neighs (struct list *is_neighs, struct stream *stream)
{
  struct listnode *node;
  struct is_neigh *is_neigh;
  u_char value [255];
  u_char *pos = value;
  int retval;

  *pos =  0; /*is_neigh->virtual; */
  pos ++;

  for (node = listhead (is_neighs); node; nextnode (node)) { 
    is_neigh = getdata (node);
    if (pos - value + IS_NEIGHBOURS_LEN > 255) {
      retval = add_tlv (IS_NEIGHBOURS, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    *pos = is_neigh->metrics.metric_default;
    pos ++;    
    *pos = is_neigh->metrics.metric_delay;
    pos ++;    
    *pos = is_neigh->metrics.metric_expense;
    pos ++;    
    *pos = is_neigh->metrics.metric_error;
    pos ++;
    memcpy (pos, is_neigh->neigh_id, ISIS_SYS_ID_LEN + 1);
    pos += ISIS_SYS_ID_LEN + 1;
  }

  return add_tlv (IS_NEIGHBOURS, pos - value, value, stream);
}


int
tlv_add_lan_neighs (struct list *lan_neighs, struct stream *stream)
{
  struct listnode *node;
  u_char *snpa;
  u_char value [255];
  u_char *pos = value;
  int retval;

  for (node = listhead (lan_neighs); node; nextnode (node)) { 
    snpa = getdata (node);
    if (pos - value + ETH_ALEN > 255) {
      retval = add_tlv (LAN_NEIGHBOURS, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    memcpy (pos, snpa, ETH_ALEN);
    pos += ETH_ALEN;
  }

  return add_tlv (LAN_NEIGHBOURS, pos - value, value, stream);
}


/*
  u_char value[255];
  u_char *pos = value;

  if (circuit->ip_router) {                             
    *pos =  (u_char)NLPID_IP;
    pos ++;
  }
  if (circuit->ipv6_router) {                         
    *pos = (u_char)NLPID_IPV6;
    pos ++;
  }
*/

int
tlv_add_nlpid (struct nlpids *nlpids, struct stream *stream)
{
  
  return add_tlv (PROTOCOLS_SUPPORTED, nlpids->count, 
                  nlpids->nlpids, stream); 
}

int tlv_add_authinfo  (char auth_type, char auth_len, char *auth_value,
		       struct stream *stream)
{
  u_char value[255];
  u_char *pos = value;
  pos++;
  memcpy (pos, auth_value, auth_len);

  return add_tlv (AUTH_INFO, auth_len + 1, value, stream);
}

int
tlv_add_checksum (struct checksum *checksum, struct stream *stream)
{
  u_char value[255];
  u_char *pos = value;  
  return add_tlv (CHECKSUM, pos - value, 
                  value, stream); 
}

int
tlv_add_ip_addrs (struct list *ip_addrs, struct stream *stream)
{
  struct listnode *node;
  struct prefix_ipv4 *ipv4;
  u_char value[255];
  u_char *pos = value;
  int retval;

  for (node = listhead (ip_addrs); node; nextnode (node)) { 
    ipv4 = getdata (node);
    if (pos - value + IPV4_MAX_BYTELEN > 255) {
      retval = add_tlv (IPV4_ADDR, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    *(u_int32_t*)pos = ipv4->prefix.s_addr;
    pos += IPV4_MAX_BYTELEN;
  }
  
  return add_tlv (IPV4_ADDR, pos - value, value, stream);
}

int
tlv_add_dynamic_hostname (struct hostname *hostname, struct stream *stream)
{
  return add_tlv (DYNAMIC_HOSTNAME, hostname->namelen, hostname->name, stream);
}

int 
tlv_add_lsp_entries (struct list *lsps, struct stream *stream)
{
  struct listnode *node;
  struct isis_lsp *lsp;
  u_char value [255];
  u_char *pos = value;
  int retval;

  for (node = listhead (lsps); node; nextnode (node)) { 
    lsp = getdata (node);
    if (pos - value + LSP_ENTRIES_LEN > 255) {
      retval = add_tlv (LSP_ENTRIES, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    *((u_int16_t*)pos) = lsp->lsp_header->rem_lifetime;
    pos += 2;
    memcpy (pos, lsp->lsp_header->lsp_id, ISIS_SYS_ID_LEN + 2);
    pos += ISIS_SYS_ID_LEN + 2;
    *((u_int32_t*)pos) = lsp->lsp_header->seq_num;
    pos += 4;    
    *((u_int16_t*)pos) = lsp->lsp_header->checksum;
    pos += 2;
  }
  
  return add_tlv (LSP_ENTRIES, pos - value, value, stream);
}

int 
tlv_add_ipv4_reachs (struct list *ipv4_reachs, struct stream *stream)
{
  struct listnode *node;
  struct ipv4_reachability *reach;
  u_char value [255];
  u_char *pos = value;
  int retval;

  for (node = listhead (ipv4_reachs); node; nextnode (node)) { 
    reach = getdata (node);
    if (pos - value + IPV4_REACH_LEN > 255) {
      retval = add_tlv (IPV4_INT_REACHABILITY, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    *pos = reach->metrics.metric_default;
    pos ++;    
    *pos = reach->metrics.metric_delay;
    pos ++;    
    *pos = reach->metrics.metric_expense;
    pos ++;    
    *pos = reach->metrics.metric_error;
    pos ++;
   *(u_int32_t*)pos = reach->prefix.s_addr;
    pos += IPV4_MAX_BYTELEN;
   *(u_int32_t*)pos = reach->mask.s_addr;
    pos += IPV4_MAX_BYTELEN;
  }    
  
  
  return add_tlv (IPV4_INT_REACHABILITY, pos - value, value, stream);
}

#ifdef HAVE_IPV6 
int
tlv_add_ipv6_addrs (struct list *ipv6_addrs, struct stream *stream)
{
  struct listnode *node;
  struct prefix_ipv6 *ipv6;
  u_char value[255];
  u_char *pos = value;
  int retval;
  
  for (node = listhead (ipv6_addrs); node; nextnode (node)) { 
    ipv6 = getdata (node);
    if (pos - value + IPV6_MAX_BYTELEN > 255) {
      retval = add_tlv (IPV6_ADDR, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    memcpy (pos, ipv6->prefix.s6_addr, IPV6_MAX_BYTELEN);
    pos += IPV6_MAX_BYTELEN;
  }
  
  return add_tlv (IPV6_ADDR, pos - value, value, stream);
}

int
tlv_add_ipv6_reachs (struct list *ipv6_reachs, struct stream *stream)
{
  struct listnode *node;
  struct ipv6_reachability *ip6reach;
  u_char value[255];
  u_char *pos = value;
  int retval, prefix_octets;
 
  for (node = listhead (ipv6_reachs); node; nextnode (node)) { 
    ip6reach = getdata (node);
    if (pos - value + IPV6_MAX_BYTELEN + 6 > 255) {
      retval = add_tlv (IPV6_REACHABILITY, pos - value, value, stream);
      if (retval != ISIS_OK)
	return retval;
      pos = value;
    }
    *(uint32_t*)pos = ip6reach->metric;
    pos += 4;
    *pos = ip6reach->control_info;
    pos++;
    prefix_octets = ((ip6reach->prefix_len + 7) / 8);
    *pos = ip6reach->prefix_len;
    pos++;
    memcpy (pos, ip6reach->prefix, prefix_octets);
    pos += prefix_octets;
  }
  
  return add_tlv (IPV6_REACHABILITY, pos - value, value, stream);
}
#endif /* HAVE_IPV6 */

int
tlv_add_padding (struct stream *stream)
{
  unsigned long putp, endp;
  int  fullpads, i, left;
  
  /*
   * How many times can we add full padding ?
   */
  fullpads = (STREAM_SIZE(stream) - stream_get_endp (stream)) / 257;
  for (i = 0; i < fullpads; i ++) {
    if (!stream_putc (stream, (u_char)PADDING)) /* TAG */
      goto err;
    if (!stream_putc (stream, (u_char)255))     /* LENGHT */
      goto err;
    endp = stream_get_endp (stream);
    putp = stream_get_putp (stream);
    if (putp != endp)
      zlog_warn ("tvl_add_padding endp %ld while putp %ld", endp, putp);
    stream_set_putp (stream, putp + 255);       /* VALUE */
    stream->endp = stream->putp;
  }
  
  left = STREAM_SIZE(stream) - stream_get_putp (stream);
  
  if (left < 2)
    return ISIS_OK;
  
  if (left == 2) {
    stream_putc (stream, PADDING);
    stream_putc (stream, 0);
    return ISIS_OK;
  }
  
  stream_putc (stream, PADDING);
  stream_putc (stream, left - 2);
  stream_set_putp (stream, stream_get_putp (stream) + left - 2);
  stream->endp = stream->putp;

  return ISIS_OK;

 err:
  zlog_warn ("tlv_add_padding(): no room for tlv");
  return ISIS_WARNING;
}