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packet-bgp.c

/* packet-bgp.c
 * Routines for BGP packet dissection.
 * Copyright 1999, Jun-ichiro itojun Hagino <itojun@itojun.org>
 *
 * $Id: packet-bgp.c 12977 2005-01-07 11:43:05Z guy $
 *
 * Supports:
 * RFC1771 A Border Gateway Protocol 4 (BGP-4)
 * RFC1965 Autonomous System Confederations for BGP
 * RFC1997 BGP Communities Attribute
 * RFC2547 BGP/MPLS VPNs
 * RFC2796 BGP Route Reflection An alternative to full mesh IBGP
 * RFC2842 Capabilities Advertisement with BGP-4
 * RFC2858 Multiprotocol Extensions for BGP-4
 * RFC2918 Route Refresh Capability for BGP-4
 * RFC3107 Carrying Label Information in BGP-4
 * draft-ietf-idr-as4bytes-06
 * draft-ietf-idr-dynamic-cap-03
 * draft-ietf-idr-bgp-ext-communities-05
 *
 * TODO:
 * Destination Preference Attribute for BGP (work in progress)
 * RFC1863 A BGP/IDRP Route Server alternative to a full mesh routing
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as 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.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>

#include <string.h>
#include <glib.h>

#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif

#include <epan/packet.h>
#include <epan/addr_and_mask.h>
#include "packet-bgp.h"
#include "packet-ipv6.h"
#include "packet-frame.h"
#include <epan/afn.h>
#include <epan/prefs.h>

static const value_string bgptypevals[] = {
    { BGP_OPEN, "OPEN Message" },
    { BGP_UPDATE, "UPDATE Message" },
    { BGP_NOTIFICATION, "NOTIFICATION Message" },
    { BGP_KEEPALIVE, "KEEPALIVE Message" },
    { BGP_ROUTE_REFRESH, "ROUTE-REFRESH Message" },
    { BGP_CAPABILITY, "CAPABILITY Message" },
    { BGP_ROUTE_REFRESH_CISCO, "Cisco ROUTE-REFRESH Message" },
    { 0, NULL },
};

static const value_string bgpnotify_major[] = {
    { 1, "Message Header Error" },
    { 2, "OPEN Message Error" },
    { 3, "UPDATE Message Error" },
    { 4, "Hold Timer Expired" },
    { 5, "Finite State Machine Error" },
    { 6, "Cease" },
    { 7, "CAPABILITY Message Error" },
    { 0, NULL },
};

static const value_string bgpnotify_minor_1[] = {
    { 1, "Connection Not Synchronized" },
    { 2, "Bad Message Length" },
    { 3, "Bad Message Type" },
    { 0, NULL },
};

static const value_string bgpnotify_minor_2[] = {
    { 1, "Unsupported Version Number" },
    { 2, "Bad Peer AS" },
    { 3, "Bad BGP Identifier" },
    { 4, "Unsupported Optional Parameter" },
    { 5, "Authentication Failure" },
    { 6, "Unacceptable Hold Time" },
    { 7, "Unsupported Capability" },
    { 0, NULL },
};

static const value_string bgpnotify_minor_3[] = {
    { 1, "Malformed Attribute List" },
    { 2, "Unrecognized Well-known Attribute" },
    { 3, "Missing Well-known Attribute" },
    { 4, "Attribute Flags Error" },
    { 5, "Attribute Length Error" },
    { 6, "Invalid ORIGIN Attribute" },
    { 7, "AS Routing Loop" },
    { 8, "Invalid NEXT_HOP Attribute" },
    { 9, "Optional Attribute Error" },
    { 10, "Invalid Network Field" },
    { 11, "Malformed AS_PATH" },
    { 0, NULL },
};

/* draft-ietf-idr-cease-subcode-02 */
static const value_string bgpnotify_minor_6[] = {
    { 1,                        "Maximum Number of Prefixes Reached"},
    { 2,                        "Administratively Shutdown"},
    { 3,                        "Peer Unconfigured"},
    { 4,                        "Administratively Reset"},
    { 5,                        "Connection Rejected"},
    { 6,                        "Other Configuration Change"},
    { 7,                        "Connection Collision Resolution"},
    { 0, NULL},
};

static const value_string bgpnotify_minor_7[] = {
    { 1, "Invalid Action Value" },
    { 2, "Invalid Capability Length" },
    { 3, "Malformed Capability Value" },
    { 4, "Unsupported Capability Code" },
    { 0, NULL },
};

static const value_string *bgpnotify_minor[] = {
    NULL,
    bgpnotify_minor_1, /* open */
    bgpnotify_minor_2, /* update */
    bgpnotify_minor_3, /* notification */
    NULL,              /* hold-timer expired */
    NULL,              /* FSM error */
    bgpnotify_minor_6, /* cease */
    bgpnotify_minor_7  /* capability */
};

static const value_string bgpattr_origin[] = {
    { 0, "IGP" },
    { 1, "EGP" },
    { 2, "INCOMPLETE" },
    { 0, NULL },
};

static const value_string as_segment_type[] = {
    { 1, "AS_SET" },
    { 2, "AS_SEQUENCE" },
/* RFC1965 has the wrong values, corrected in  */
/* draft-ietf-idr-bgp-confed-rfc1965bis-01.txt */
    { 4, "AS_CONFED_SET" },
    { 3, "AS_CONFED_SEQUENCE" },
    { 0, NULL },
};

static const value_string bgpattr_type[] = {
    { BGPTYPE_ORIGIN, "ORIGIN" },
    { BGPTYPE_AS_PATH, "AS_PATH" },
    { BGPTYPE_NEXT_HOP, "NEXT_HOP" },
    { BGPTYPE_MULTI_EXIT_DISC, "MULTI_EXIT_DISC" },
    { BGPTYPE_LOCAL_PREF, "LOCAL_PREF" },
    { BGPTYPE_ATOMIC_AGGREGATE, "ATOMIC_AGGREGATE" },
    { BGPTYPE_AGGREGATOR, "AGGREGATOR" },
    { BGPTYPE_COMMUNITIES, "COMMUNITIES" },
    { BGPTYPE_ORIGINATOR_ID, "ORIGINATOR_ID" },
    { BGPTYPE_CLUSTER_LIST, "CLUSTER_LIST" },
    { BGPTYPE_MP_REACH_NLRI, "MP_REACH_NLRI" },
    { BGPTYPE_MP_UNREACH_NLRI, "MP_UNREACH_NLRI" },
    { BGPTYPE_EXTENDED_COMMUNITY, "EXTENDED_COMMUNITIES" },
    { BGPTYPE_NEW_AS_PATH, "NEW_AS_PATH" },
    { BGPTYPE_NEW_AGGREGATOR, "NEW_AGGREGATOR" },
    { BGPTYPE_SAFI_SPECIFIC_ATTR, "SAFI_SPECIFIC_ATTRIBUTE" },
    { 0, NULL },
};

static const value_string bgpext_com_type[] = {
    { BGP_EXT_COM_RT_0, "Route Target" },
    { BGP_EXT_COM_RT_1, "Route Target" },
    { BGP_EXT_COM_RT_2, "Route Target" },
    { BGP_EXT_COM_RO_0, "Route Origin" },
    { BGP_EXT_COM_RO_1, "Route Origin" },
    { BGP_EXT_COM_RO_2, "Route Origin" },
    { BGP_EXT_COM_LINKBAND, "Link Bandwidth" },
    { BGP_EXT_COM_VPN_ORIGIN, "OSPF Domain" },
    { BGP_EXT_COM_OSPF_RTYPE, "OSPF Route Type" },
    { BGP_EXT_COM_OSPF_RID, "OSPF Router ID" },
    { BGP_EXT_COM_L2INFO, "Layer 2 Information" },
    { 0, NULL },
};

static const value_string bgp_ssa_type[] = {
    { BGP_SSA_L2TPv3 , "L2TPv3 Tunnel" },
    { BGP_SSA_mGRE , "mGRE Tunnel" },
    { BGP_SSA_IPSec , "IPSec Tunnel" },
    { BGP_SSA_MPLS , "MPLS Tunnel" },
    { 0, NULL },
};

static const value_string bgp_l2vpn_encaps[] = {
    { 0,                      "Reserved"},
    { 1,                      "Frame Relay"},
    { 2,                      "ATM AAL5 VCC transport"},
    { 3,                      "ATM transparent cell transport"},
    { 4,                      "Ethernet VLAN"},
    { 5,                      "Ethernet"},
    { 6,                      "Cisco-HDLC"},
    { 7,                      "PPP"},
    { 8,                      "CEM"},
    { 9,                      "ATM VCC cell transport"},
    { 10,                     "ATM VPC cell transport"},
    { 11,                     "MPLS"},
    { 12,                     "VPLS"},
    { 64,                     "IP-interworking"},
    { 0, NULL},
};

static const value_string bgpext_ospf_rtype[] = {
  { BGP_OSPF_RTYPE_RTR, "Router" },
  { BGP_OSPF_RTYPE_NET, "Network" },
  { BGP_OSPF_RTYPE_SUM, "Summary" },
  { BGP_OSPF_RTYPE_EXT, "External" },
  { BGP_OSPF_RTYPE_NSSA,"NSSA External" },
  { BGP_OSPF_RTYPE_SHAM,"MPLS-VPN Sham" },
  { 0, NULL },
};

/* Subsequent address family identifier, RFC2858 */
static const value_string bgpattr_nlri_safi[] = {
    { 0, "Reserved" },
    { SAFNUM_UNICAST, "Unicast" },
    { SAFNUM_MULCAST, "Multicast" },
    { SAFNUM_UNIMULC, "Unicast+Multicast" },
    { SAFNUM_MPLS_LABEL, "Labeled Unicast"},
    { SAFNUM_TUNNEL, "Tunnel"},
    { SAFNUM_LAB_VPNUNICAST, "Labeled VPN Unicast" },        /* draft-rosen-rfc2547bis-03 */
    { SAFNUM_LAB_VPNMULCAST, "Labeled VPN Multicast" },
    { SAFNUM_LAB_VPNUNIMULC, "Labeled VPN Unicast+Multicast" },
    { 0, NULL },
};

/* ORF Type, draft-ietf-idr-route-filter-04.txt */
static const value_string orf_type_vals[] = {
    { 2,    "Communities ORF-Type" },
    { 3,    "Extended Communities ORF-Type" },
    { 128,  "Cisco PrefixList ORF-Type" },
    { 129,  "Cisco CommunityList ORF-Type" },
    { 130,  "Cisco Extended CommunityList ORF-Type" },
    { 131,  "Cisco AsPathList ORF-Type" },
    { 0,    NULL },
};

/* ORF Send/Receive, draft-ietf-idr-route-filter-04.txt */
static const value_string orf_send_recv_vals[] = {
    { 1,    "Receive" },
    { 2,    "Send" },
    { 3,    "Both" },
    { 0,    NULL },
};

/* ORF Send/Receive, draft-ietf-idr-route-filter-04.txt */
static const value_string orf_when_vals[] = {
    { 1,    "Immediate" },
    { 2,    "Defer" },
    { 0,    NULL },
};

static const value_string orf_entry_action_vals[] = {
    { 0,    "Add" },
    { 0x40, "Remove" },
    { 0x80, "RemoveAll" },
    { 0,    NULL },
};

static const value_string orf_entry_match_vals[] = {
    { 0,    "Permit" },
    { 0x20, "Deny" },
    { 0,    NULL },
};

static const value_string capability_vals[] = {
    { BGP_CAPABILITY_RESERVED, "Reserved capability" },
    { BGP_CAPABILITY_MULTIPROTOCOL, "Multiprotocol extensions capability" },
    { BGP_CAPABILITY_ROUTE_REFRESH, "Route refresh capability" },
    { BGP_CAPABILITY_COOPERATIVE_ROUTE_FILTERING, "Cooperative route filtering capability" },
    { BGP_CAPABILITY_GRACEFUL_RESTART, "Graceful Restart capability" },
    { BGP_CAPABILITY_4_OCTET_AS_NUMBER, "Support for 4-octet AS number capability" },
    { BGP_CAPABILITY_DYNAMIC_CAPABILITY, "Support for Dynamic capability" },
    { BGP_CAPABILITY_ROUTE_REFRESH_CISCO, "Route refresh capability" },
    { BGP_CAPABILITY_ORF_CISCO, "Cooperative route filtering capability" },
};

/* Capability Message action code */
static const value_string bgpcap_action[] = {
    { 0, "advertising a capability" },
    { 1, "removing a capability" },
    { 0, NULL },
};


/* Maximal size of an IP address string */
#define MAX_SIZE_OF_IP_ADDR_STRING      16

static int proto_bgp = -1;
static int hf_bgp_type = -1;
static int hf_bgp_next_hop = -1;
static int hf_bgp_as_path = -1;
static int hf_bgp_cluster_identifier = -1;
static int hf_bgp_community_as = -1;
static int hf_bgp_community_value = -1;
static int hf_bgp_origin = -1;
static int hf_bgp_cluster_list = -1;
static int hf_bgp_originator_id = -1;
static int hf_bgp_ssa_t = -1;
static int hf_bgp_ssa_type = -1;
static int hf_bgp_ssa_len = -1;
static int hf_bgp_ssa_value = -1;
static int hf_bgp_ssa_l2tpv3_pref = -1;
static int hf_bgp_ssa_l2tpv3_s = -1;
static int hf_bgp_ssa_l2tpv3_unused = -1;
static int hf_bgp_ssa_l2tpv3_cookie_len = -1;
static int hf_bgp_ssa_l2tpv3_session_id = -1;
static int hf_bgp_ssa_l2tpv3_cookie = -1;
static int hf_bgp_local_pref = -1;
static int hf_bgp_multi_exit_disc = -1;
static int hf_bgp_aggregator_as = -1;
static int hf_bgp_aggregator_origin = -1;
static int hf_bgp_mp_reach_nlri_ipv4_prefix = -1;
static int hf_bgp_mp_unreach_nlri_ipv4_prefix = -1;
static int hf_bgp_mp_nlri_tnl_id = -1;
static int hf_bgp_withdrawn_prefix = -1;
static int hf_bgp_nlri_prefix = -1;

static gint ett_bgp = -1;
static gint ett_bgp_prefix = -1;
static gint ett_bgp_unfeas = -1;
static gint ett_bgp_attrs = -1;
static gint ett_bgp_attr = -1;
static gint ett_bgp_attr_flags = -1;
static gint ett_bgp_mp_nhna = -1;
static gint ett_bgp_mp_reach_nlri = -1;
static gint ett_bgp_mp_unreach_nlri = -1;
static gint ett_bgp_mp_snpa = -1;
static gint ett_bgp_nlri = -1;
static gint ett_bgp_open = -1;
static gint ett_bgp_update = -1;
static gint ett_bgp_notification = -1;
static gint ett_bgp_route_refresh = -1; /* ROUTE-REFRESH message tree */
static gint ett_bgp_capability = -1;
static gint ett_bgp_as_paths = -1;
static gint ett_bgp_as_path_segments = -1;
static gint ett_bgp_communities = -1;
static gint ett_bgp_cluster_list = -1;  /* cluster list tree          */
static gint ett_bgp_options = -1;       /* optional parameters tree   */
static gint ett_bgp_option = -1;        /* an optional parameter tree */
static gint ett_bgp_extended_communities = -1 ; /* extended communities list tree */
static gint ett_bgp_ssa = -1;       /* safi specific attribute */
static gint ett_bgp_ssa_subtree = -1;     /* safi specific attribute Subtrees */
static gint ett_bgp_orf = -1;             /* orf (outbound route filter) tree */
static gint ett_bgp_orf_entry = -1;             /* orf entry tree */

/* desegmentation */
static gboolean bgp_desegment = TRUE;

static gint bgp_asn_len = 0;

/*
 * Decode an IPv4 prefix.
 */
static int
decode_prefix4(proto_tree *tree, int hf_addr, tvbuff_t *tvb, gint offset,
    guint16 tlen, char *tag)
{
    proto_item *ti;
    proto_tree *prefix_tree;
    union {
       guint8 addr_bytes[4];
       guint32 addr;
    } ip_addr;        /* IP address                         */
    guint8 plen;      /* prefix length                      */
    int    length;    /* number of octets needed for prefix */

    /* snarf length and prefix */
    plen = tvb_get_guint8(tvb, offset);
    length = ipv4_addr_and_mask(tvb, offset + 1, ip_addr.addr_bytes, plen);
    if (length < 0) {
      proto_tree_add_text(tree, tvb, offset, 1, "%s length %u invalid (> 32)",
          tag, plen);
      return -1;
    }

    /* put prefix into protocol tree */
    ti = proto_tree_add_text(tree, tvb, offset,
            tlen != 0 ? tlen : 1 + length, "%s/%u",
      ip_to_str(ip_addr.addr_bytes), plen);
    prefix_tree = proto_item_add_subtree(ti, ett_bgp_prefix);
    proto_tree_add_text(prefix_tree, tvb, offset, 1, "%s prefix length: %u",
      tag, plen);
    if (hf_addr != -1) {
      proto_tree_add_ipv4(prefix_tree, hf_addr, tvb, offset + 1, length,
          ip_addr.addr);
    } else {
      proto_tree_add_text(prefix_tree, tvb, offset + 1, length,
          "%s prefix: %s", tag, ip_to_str(ip_addr.addr_bytes));
    }
    return(1 + length);
}

/*
 * Decode an IPv6 prefix.
 */
static int
decode_prefix6(proto_tree *tree, int hf_addr, tvbuff_t *tvb, gint offset,
    guint16 tlen, char *tag)
{
    proto_item        *ti;
    proto_tree        *prefix_tree;
    struct e_in6_addr addr;     /* IPv6 address                       */
    int               plen;     /* prefix length                      */
    int               length;   /* number of octets needed for prefix */

    /* snarf length and prefix */
    plen = tvb_get_guint8(tvb, offset);
    length = ipv6_addr_and_mask(tvb, offset + 1, &addr, plen);
    if (length < 0) {
      proto_tree_add_text(tree, tvb, offset, 1, "%s length %u invalid",
          tag, plen);
      return -1;
    }

    /* put prefix into protocol tree */
    ti = proto_tree_add_text(tree, tvb, offset,
            tlen != 0 ? tlen : 1 + length, "%s/%u",
            ip6_to_str(&addr), plen);
    prefix_tree = proto_item_add_subtree(ti, ett_bgp_prefix);
    proto_tree_add_text(prefix_tree, tvb, offset, 1, "%s prefix length: %u",
      tag, plen);
    if (hf_addr != -1) {
      proto_tree_add_ipv6(prefix_tree, hf_addr, tvb, offset + 1, length,
          addr.s6_addr);
    } else {
      proto_tree_add_text(prefix_tree, tvb, offset + 1, length,
          "%s prefix: %s", tag, ip6_to_str(&addr));
    }
    return(1 + length);
}



/*
 * Decode an MPLS label stack
 * XXX - Should we convert "buf" to a GString?
 */
static guint
decode_MPLS_stack(tvbuff_t *tvb, gint offset, char *buf, size_t buflen)
{
    guint32     label_entry;    /* an MPLS label enrty (label + COS field + stack bit   */
    gint        index;          /* index for the label stack                            */
    char        junk_buf[256];  /* tmp                                                  */

    index = offset ;
    label_entry = 0x000000 ;

    buf[0] = '\0' ;

    while ((label_entry & 0x000001) == 0) {

        label_entry = tvb_get_ntoh24(tvb, index) ;

        /* withdrawn routes may contain 0 or 0x800000 in the first label */
        if((index-offset)==0&&(label_entry==0||label_entry==0x800000)) {
            snprintf(buf, buflen, "0 (withdrawn)");
            return (1);
        }

        snprintf(junk_buf, sizeof(junk_buf),"%u%s", (label_entry >> 4), ((label_entry & 0x000001) == 0) ? "," : " (bottom)");
      if (strlen(buf) + strlen(junk_buf) + 1 <= buflen)
          strcat(buf, junk_buf);
        index += 3 ;

      if ((label_entry & 0x000001) == 0) {
          /* real MPLS multi-label stack in BGP? - maybe later; for now, it must be a bogus packet */
          strcpy(junk_buf, " (BOGUS: Bottom of Stack NOT set!)");
          if (strlen(buf) + strlen(junk_buf) + 1 <= buflen)
            strcat(buf, junk_buf);
          break;
      }
    }

    return((index - offset) / 3);
}

/*
 * Decode a multiprotocol address
 */

static int
mp_addr_to_str (guint16 afi, guint8 safi, tvbuff_t *tvb, gint offset, GString *buf)
{
    int                 length;                         /* length of the address in byte */
    guint8              ip4addr[4],ip4addr2[4];         /* IPv4 address                 */
    guint16             rd_type;                        /* Route Distinguisher type     */
    struct e_in6_addr   ip6addr;                        /* IPv6 address                 */

    length = 0 ;
    switch (afi) {
        case AFNUM_INET:
                switch (safi) {
                        case SAFNUM_UNICAST:
                        case SAFNUM_MULCAST:
                        case SAFNUM_UNIMULC:
                        case SAFNUM_MPLS_LABEL:
                  case SAFNUM_TUNNEL:
                                length = 4 ;
                                tvb_memcpy(tvb, ip4addr, offset, sizeof(ip4addr));
                          g_string_sprintf(buf, "%s", ip_to_str(ip4addr));
                                break;
                        case SAFNUM_LAB_VPNUNICAST:
                        case SAFNUM_LAB_VPNMULCAST:
                        case SAFNUM_LAB_VPNUNIMULC:
                                rd_type=tvb_get_ntohs(tvb,offset) ;
                                switch (rd_type) {
                                        case FORMAT_AS2_LOC:
                                                length = 8 + sizeof(ip4addr);
                                                tvb_memcpy(tvb, ip4addr, offset + 8, sizeof(ip4addr));   /* Next Hop */
                                                g_string_sprintf(buf, "Empty Label Stack RD=%u:%u IPv4=%s",
                                                                tvb_get_ntohs(tvb, offset + 2),
                                                                tvb_get_ntohl(tvb, offset + 4),
                                                                ip_to_str(ip4addr));
                                                break;
                                        case FORMAT_IP_LOC:
                                                length = 8 + sizeof(ip4addr);
                                                tvb_memcpy(tvb, ip4addr, offset + 2, sizeof(ip4addr));   /* IP part of the RD            */
                                                tvb_memcpy(tvb, ip4addr2, offset + 8, sizeof(ip4addr));  /* Next Hop   */
                                                g_string_sprintf(buf, "Empty Label Stack RD=%s:%u IPv4=%s",
                                                                ip_to_str(ip4addr),
                                                                tvb_get_ntohs(tvb, offset + 6),
                                                                ip_to_str(ip4addr2));
                                                break ;
                                        default:
                                                length = 0 ;
                                                g_string_sprintf(buf, "Unknown (0x%04x) labeled VPN IPv4 address format",rd_type);
                                                break;
                                }
                                break;
                        default:
                            length = 0 ;
                            g_string_sprintf(buf, "Unknown SAFI (%u) for AFI %u", safi, afi);
                            break;
                }
                break;
        case AFNUM_INET6:
                switch (safi) {
                        case SAFNUM_UNICAST:
                        case SAFNUM_MULCAST:
                        case SAFNUM_UNIMULC:
                        case SAFNUM_MPLS_LABEL:
                  case SAFNUM_TUNNEL:
                            length = 16 ;
                            tvb_memcpy(tvb, ip6addr.u6_addr.u6_addr8,offset, 16);
                            g_string_sprintf(buf, "%s", ip6_to_str(&ip6addr));
                            break;
                        case SAFNUM_LAB_VPNUNICAST:
                        case SAFNUM_LAB_VPNMULCAST:
                        case SAFNUM_LAB_VPNUNIMULC:
                                rd_type=tvb_get_ntohs(tvb,offset) ;
                                switch (rd_type) {
                                        case FORMAT_AS2_LOC:
                                                length = 8 + 16;
                                                tvb_memcpy(tvb, ip6addr.u6_addr.u6_addr8, offset + 8, 16); /* Next Hop */
                                                g_string_sprintf(buf, "Empty Label Stack RD=%u:%u IPv6=%s",
                                                                tvb_get_ntohs(tvb, offset + 2),
                                                                tvb_get_ntohl(tvb, offset + 4),
                                                                ip6_to_str(&ip6addr));
                                                break;
                                        case FORMAT_IP_LOC:
                                                length = 8 + 16;
                                                tvb_memcpy(tvb, ip4addr, offset + 2, sizeof(ip4addr));   /* IP part of the RD            */
                                                tvb_memcpy(tvb, ip6addr.u6_addr.u6_addr8, offset + 8, 16); /* Next Hop */
                                                g_string_sprintf(buf, "Empty Label Stack RD=%s:%u IPv6=%s",
                                                                ip_to_str(ip4addr),
                                                                tvb_get_ntohs(tvb, offset + 6),
                                                                ip6_to_str(&ip6addr));
                                                break ;
                                        default:
                                                length = 0 ;
                                                g_string_sprintf(buf, "Unknown (0x%04x) labeled VPN IPv6 address format",rd_type);
                                                break;
                                }
                                break;
                        default:
                            length = 0 ;
                            g_string_sprintf(buf, "Unknown SAFI (%u) for AFI %u", safi, afi);
                            break;
                }
                break;
       case AFNUM_L2VPN:
                switch (safi) {
                        case SAFNUM_LAB_VPNUNICAST: /* only labeles prefixes do make sense */
                        case SAFNUM_LAB_VPNMULCAST:
                        case SAFNUM_LAB_VPNUNIMULC:
                            length = 4; /* the next-hop is simply an ipv4 addr */
                            tvb_memcpy(tvb, ip4addr, offset + 0, 4);
                            g_string_sprintf(buf, "IPv4=%s",
                                     ip_to_str(ip4addr));
                            break;
                        default:
                            length = 0 ;
                            g_string_sprintf(buf, "Unknown SAFI (%u) for AFI %u", safi, afi);
                            break;
                }
                break;
        default:
                length = 0 ;
                g_string_sprintf(buf, "Unknown AFI (%u) value", afi);
                break;
    }
    return(length) ;
}

/*
 * Decode a multiprotocol prefix
 */
static int
decode_prefix_MP(proto_tree *tree, int hf_addr4, int hf_addr6,
    guint16 afi, guint8 safi, tvbuff_t *tvb, gint offset, char *tag)
{
    int                 start_offset = offset;
    proto_item          *ti;
    proto_tree          *prefix_tree;
    int                 total_length;       /* length of the entire item */
    int                 length;             /* length of the prefix address, in bytes */
    guint               plen;               /* length of the prefix address, in bits */
    guint               labnum;             /* number of labels             */
    guint16       tnl_id;               /* Tunnel Identifier */
    int                 ce_id,labblk_off;
    union {
       guint8 addr_bytes[4];
       guint32 addr;
    } ip4addr, ip4addr2;                    /* IPv4 address                 */
    struct e_in6_addr   ip6addr;            /* IPv6 address                 */
    guint16             rd_type;            /* Route Distinguisher type     */
    char                lab_stk[256];       /* label stack                  */

    switch (afi) {

    case AFNUM_INET:
        switch (safi) {

        case SAFNUM_UNICAST:
        case SAFNUM_MULCAST:
        case SAFNUM_UNIMULC:
            total_length = decode_prefix4(tree, hf_addr4, tvb, offset, 0, tag);
            if (total_length < 0)
                return -1;
            break;

        case SAFNUM_MPLS_LABEL:
            plen =  tvb_get_guint8(tvb, offset);
            labnum = decode_MPLS_stack(tvb, offset + 1, lab_stk, sizeof(lab_stk));

            offset += (1 + labnum * 3);
            if (plen <= (labnum * 3*8)) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled IPv4 prefix length %u invalid",
                        tag, plen);
                return -1;
            }
            plen -= (labnum * 3*8);
            length = ipv4_addr_and_mask(tvb, offset, ip4addr.addr_bytes, plen);
            if (length < 0) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled IPv4 prefix length %u invalid",
                        tag, plen + (labnum * 3*8));
                return -1;
            }

            ti = proto_tree_add_text(tree, tvb, start_offset,
                    (offset + length) - start_offset,
                    "Label Stack=%s IPv4=%s/%u",
                    lab_stk, ip_to_str(ip4addr.addr_bytes), plen);
            prefix_tree = proto_item_add_subtree(ti, ett_bgp_prefix);
            proto_tree_add_text(prefix_tree, tvb, start_offset, 1, "%s Prefix length: %u",
                tag, plen + labnum * 3 * 8);
            proto_tree_add_text(prefix_tree, tvb, start_offset + 1, 3 * labnum, "%s Label Stack: %s",
                tag, lab_stk);
            if (hf_addr4 != -1) {
                proto_tree_add_ipv4(prefix_tree, hf_addr4, tvb, offset,
                        length, ip4addr.addr);
            } else {
                proto_tree_add_text(prefix_tree, tvb, offset, length,
                        "%s IPv4 prefix: %s",
                        tag, ip_to_str(ip4addr.addr_bytes));
            }
            total_length = (1 + labnum*3) + length;
            break;

      case SAFNUM_TUNNEL:
          plen =  tvb_get_guint8(tvb, offset);
          if (plen <= 16){
            proto_tree_add_text(tree, tvb, start_offset, 1,
                  "%s Tunnel IPv4 prefix length %u invalid",
                  tag, plen);
            return -1;
          }
          tnl_id = tvb_get_ntohs(tvb, offset + 1);
          offset += 3; /* Length + Tunnel Id */
          plen -= 16; /* 2-octet Identifier */
          length = ipv4_addr_and_mask(tvb, offset, ip4addr.addr_bytes, plen);
          if (length < 0) {
            proto_tree_add_text(tree, tvb, start_offset, 1,
                  "%s Tunnel IPv4 prefix length %u invalid",
                  tag, plen + 16);
            return -1;
          }
          ti = proto_tree_add_text(tree, tvb, start_offset,
                  (offset + length) - start_offset,
                  "Tunnel Identifier=0x%x IPv4=%s/%u",
                  tnl_id, ip_to_str(ip4addr.addr_bytes), plen);
          prefix_tree = proto_item_add_subtree(ti, ett_bgp_prefix);

          proto_tree_add_text(prefix_tree, tvb, start_offset, 1, "%s Prefix length: %u",
            tag, plen + 16);
          proto_tree_add_item(prefix_tree, hf_bgp_mp_nlri_tnl_id, tvb,
                        start_offset + 1, 2, FALSE);
          if (hf_addr4 != -1) {
            proto_tree_add_ipv4(prefix_tree, hf_addr4, tvb, offset,
                        length, ip4addr.addr);
          } else {
            proto_tree_add_text(prefix_tree, tvb, offset, length,
                  "%s IPv4 prefix: %s",
                  tag, ip_to_str(ip4addr.addr_bytes));
          }
          total_length = 1 + 2 + length; /* length field + Tunnel Id + IPv4 len */
          break;

        case SAFNUM_LAB_VPNUNICAST:
        case SAFNUM_LAB_VPNMULCAST:
        case SAFNUM_LAB_VPNUNIMULC:
            plen =  tvb_get_guint8(tvb, offset);
            labnum = decode_MPLS_stack(tvb, offset + 1, lab_stk, sizeof(lab_stk));

            offset += (1 + labnum * 3);
            if (plen <= (labnum * 3*8)) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled VPN IPv4 prefix length %u invalid",
                        tag, plen);
                return -1;
            }
            plen -= (labnum * 3*8);

            rd_type = tvb_get_ntohs(tvb, offset);
            if (plen <= 8*8) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled VPN IPv4 prefix length %u invalid",
                        tag, plen + (labnum * 3*8));
                return -1;
            }
            plen -= 8*8;

            switch (rd_type) {

            case FORMAT_AS2_LOC: /* Code borrowed from the decode_prefix4 function */
                length = ipv4_addr_and_mask(tvb, offset + 8, ip4addr.addr_bytes, plen);
                if (length < 0) {
                    proto_tree_add_text(tree, tvb, start_offset, 1,
                            "%s Labeled VPN IPv4 prefix length %u invalid",
                            tag, plen + (labnum * 3*8) + 8*8);
                    return -1;
                }

                ti = proto_tree_add_text(tree, tvb, start_offset,
                        (offset + 8 + length) - start_offset,
                        "Label Stack=%s RD=%u:%u, IPv4=%s/%u",
                        lab_stk,
                        tvb_get_ntohs(tvb, offset + 2),
                        tvb_get_ntohl(tvb, offset + 4),
                        ip_to_str(ip4addr.addr_bytes), plen);
                prefix_tree = proto_item_add_subtree(ti, ett_bgp_prefix);
                proto_tree_add_text(prefix_tree, tvb, start_offset, 1, "%s Prefix length: %u",
                        tag, plen + labnum * 3 * 8 + 8 * 8);
                proto_tree_add_text(prefix_tree, tvb, start_offset + 1, 3 * labnum,
                        "%s Label Stack: %s", tag, lab_stk);
                proto_tree_add_text(prefix_tree, tvb, start_offset + 1 + 3 * labnum, 8,
                        "%s Route Distinguisher: %u:%u", tag, tvb_get_ntohs(tvb, offset + 2),
                        tvb_get_ntohl(tvb, offset + 4));
                if (hf_addr4 != -1) {
                    proto_tree_add_ipv4(prefix_tree, hf_addr4, tvb,
                            offset + 8, length, ip4addr.addr);
                } else {
                    proto_tree_add_text(prefix_tree, tvb, offset + 8,
                            length, "%s IPv4 prefix: %s", tag,
                            ip_to_str(ip4addr.addr_bytes));
                }
                total_length = (1 + labnum * 3 + 8) + length;
                break;

            case FORMAT_IP_LOC: /* Code borrowed from the decode_prefix4 function */
                tvb_memcpy(tvb, ip4addr.addr_bytes, offset + 2, 4);

                length = ipv4_addr_and_mask(tvb, offset + 8, ip4addr2.addr_bytes, plen);
                if (length < 0) {
                        proto_tree_add_text(tree, tvb, start_offset, 1,
                                "%s Labeled VPN IPv4 prefix length %u invalid",
                                tag, plen + (labnum * 3*8) + 8*8);
                        return -1;
                }

                ti = proto_tree_add_text(tree, tvb, start_offset,
                        (offset + 8 + length) - start_offset,
                        "Label Stack=%s RD=%s:%u, IPv4=%s/%u",
                        lab_stk,
                        ip_to_str(ip4addr.addr_bytes),
                        tvb_get_ntohs(tvb, offset + 6),
                        ip_to_str(ip4addr2.addr_bytes),
                        plen);
            prefix_tree = proto_item_add_subtree(ti, ett_bgp_prefix);
            proto_tree_add_text(prefix_tree, tvb, start_offset, 1, "%s Prefix length: %u",
                  tag, plen + labnum * 3 * 8 + 8 * 8);
            proto_tree_add_text(prefix_tree, tvb, start_offset + 1, 3 * labnum,
                  "%s Label Stack: %s", tag, lab_stk);
            proto_tree_add_text(prefix_tree, tvb, start_offset + 1 + 3 * labnum, 8,
                  "%s Route Distinguisher: %s:%u", tag, ip_to_str(ip4addr.addr_bytes),
                  tvb_get_ntohs(tvb, offset + 6));
            if (hf_addr4 != -1) {
                  proto_tree_add_ipv4(prefix_tree, hf_addr4, tvb,
                        offset + 8, length, ip4addr2.addr);
            } else {
                  proto_tree_add_text(prefix_tree, tvb, offset + 8,
                        length, "%s IPv4 prefix: %s", tag,
                        ip_to_str(ip4addr2.addr_bytes));
            }
                total_length = (1 + labnum * 3 + 8) + length;
                break;

            default:
                proto_tree_add_text(tree, tvb, start_offset,
                        (offset - start_offset) + 2,
                        "Unknown labeled VPN IPv4 address format %u", rd_type);
                return -1;
            }
            break;

        default:
            proto_tree_add_text(tree, tvb, start_offset, 0,
                    "Unknown SAFI (%u) for AFI %u", safi, afi);
            return -1;
        }
        break;

    case AFNUM_INET6:
        switch (safi) {

        case SAFNUM_UNICAST:
        case SAFNUM_MULCAST:
        case SAFNUM_UNIMULC:
            total_length = decode_prefix6(tree, hf_addr6, tvb, offset, 0, tag);
            if (total_length < 0)
                return -1;
            break;

        case SAFNUM_MPLS_LABEL:
            plen =  tvb_get_guint8(tvb, offset);
            labnum = decode_MPLS_stack(tvb, offset + 1, lab_stk, sizeof(lab_stk));

            offset += (1 + labnum * 3);
            if (plen <= (labnum * 3*8)) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled IPv6 prefix length %u invalid", tag, plen);
                return -1;
            }
            plen -= (labnum * 3*8);

            length = ipv6_addr_and_mask(tvb, offset, &ip6addr, plen);
            if (length < 0) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled IPv6 prefix length %u invalid",
                  tag, plen  + (labnum * 3*8));
                return -1;
            }

          ti = proto_tree_add_text(tree, tvb, start_offset,
             (offset + length) - start_offset,
                 "Label Stack=%s, IPv6=%s/%u",
                 lab_stk,
                 ip6_to_str(&ip6addr), plen);
          total_length = (1 + labnum * 3) + length;
          break;

      case SAFNUM_TUNNEL:
            plen =  tvb_get_guint8(tvb, offset);
            if (plen <= 16){
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Tunnel IPv6 prefix length %u invalid",
                        tag, plen);
                return -1;
            }
            tnl_id = tvb_get_ntohs(tvb, offset + 1);
            offset += 3; /* Length + Tunnel Id */
            plen -= 16; /* 2-octet Identifier */
            length = ipv6_addr_and_mask(tvb, offset, &ip6addr, plen);
            if (length < 0) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Tunnel IPv6 prefix length %u invalid",
                        tag, plen + 16);
                return -1;
            }
            ti = proto_tree_add_text(tree, tvb, start_offset,
                        (offset + length) - start_offset,
                        "Tunnel Identifier=0x%x IPv6=%s/%u",
                        tnl_id, ip6_to_str(&ip6addr), plen);
            total_length = (1 + 2) + length; /* length field + Tunnel Id + IPv4 len */
            break;

        case SAFNUM_LAB_VPNUNICAST:
        case SAFNUM_LAB_VPNMULCAST:
        case SAFNUM_LAB_VPNUNIMULC:
            plen =  tvb_get_guint8(tvb, offset);
            labnum = decode_MPLS_stack(tvb, offset + 1, lab_stk, sizeof(lab_stk));

            offset += (1 + labnum * 3);
            if (plen <= (labnum * 3*8)) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled VPN IPv6 prefix length %u invalid", tag, plen);
                return -1;
            }
            plen -= (labnum * 3*8);

            rd_type = tvb_get_ntohs(tvb,offset);
            if (plen <= 8*8) {
                proto_tree_add_text(tree, tvb, start_offset, 1,
                        "%s Labeled VPN IPv6 prefix length %u invalid",
                        tag, plen + (labnum * 3*8));
                return -1;
            }
            plen -= 8*8;

            switch (rd_type) {

            case FORMAT_AS2_LOC:
                length = ipv6_addr_and_mask(tvb, offset + 8, &ip6addr, plen);
                if (length < 0) {
                    proto_tree_add_text(tree, tvb, start_offset, 1,
                            "%s Labeled VPN IPv6 prefix length %u invalid",
                            tag, plen + (labnum * 3*8) + 8*8);
                    return -1;
                }

                ti = proto_tree_add_text(tree, tvb, start_offset,
                        (offset + 8 + length) - start_offset,
                        "Label Stack=%s RD=%u:%u, IPv6=%s/%u",
                        lab_stk,
                        tvb_get_ntohs(tvb, offset + 2),
                        tvb_get_ntohl(tvb, offset + 4),
                        ip6_to_str(&ip6addr), plen);
                total_length = (1 + labnum * 3 + 8) + length;
                break;

            case FORMAT_IP_LOC: 
                tvb_memcpy(tvb, ip4addr.addr_bytes, offset + 2, 4);

                length = ipv6_addr_and_mask(tvb, offset + 8, &ip6addr, plen);
                if (length < 0) {
                    proto_tree_add_text(tree, tvb, start_offset, 1,
                            "%s Labeled VPN IPv6 prefix length %u invalid",
                            tag, plen + (labnum * 3*8) + 8*8);
                    return -1;
                }

                ti = proto_tree_add_text(tree, tvb, start_offset,
                        (offset + 8 + length) - start_offset,
                        "Label Stack=%s RD=%s:%u, IPv6=%s/%u",
                        lab_stk,
                        ip_to_str(ip4addr.addr_bytes),
                        tvb_get_ntohs(tvb, offset + 6),
                        ip6_to_str(&ip6addr), plen);
                total_length = (1 + labnum * 3 + 8) + length;
                break;

            default:
                proto_tree_add_text(tree, tvb, start_offset, 0,
                        "Unknown labeled VPN IPv6 address format %u", rd_type);
                return -1;
            }
            break;

        default:
            proto_tree_add_text(tree, tvb, start_offset, 0,
                    "Unknown SAFI (%u) for AFI %u", safi, afi);
            return -1;
        }
        break;

    case AFNUM_L2VPN:
        switch (safi) {

        case SAFNUM_LAB_VPNUNICAST:
        case SAFNUM_LAB_VPNMULCAST:
        case SAFNUM_LAB_VPNUNIMULC:
            plen =  tvb_get_ntohs(tvb,offset);
            rd_type=tvb_get_ntohs(tvb,offset+2);
            ce_id=tvb_get_ntohs(tvb,offset+10);
            labblk_off=tvb_get_ntohs(tvb,offset+12);
            labnum = decode_MPLS_stack(tvb, offset + 14, lab_stk, sizeof(lab_stk));

            switch (rd_type) {

            case FORMAT_AS2_LOC:
                tvb_memcpy(tvb, ip4addr.addr_bytes, offset + 6, 4);
                proto_tree_add_text(tree, tvb, start_offset,
                        (offset + plen + 1) - start_offset,
                        "RD: %u:%s, CE-ID: %u, Label-Block Offset: %u, Label Base %s",
                        tvb_get_ntohs(tvb, offset + 4),
                        ip_to_str(ip4addr.addr_bytes),
                        ce_id,
                        labblk_off,
                        lab_stk);
                break;

            case FORMAT_IP_LOC:
                tvb_memcpy(tvb, ip4addr.addr_bytes, offset + 4, 4);
                proto_tree_add_text(tree, tvb, offset,
                        (offset + plen + 1) - start_offset,
                        "RD: %s:%u, CE-ID: %u, Label-Block Offset: %u, Label Base %s",
                        ip_to_str(ip4addr.addr_bytes),
                        tvb_get_ntohs(tvb, offset + 8),
                        ce_id,
                        labblk_off,
                        lab_stk);
                break;

            default:
                proto_tree_add_text(tree, tvb, start_offset,
                        (offset - start_offset) + 2,
                        "Unknown labeled VPN address format %u", rd_type);
                return -1;
            }
            /* FIXME there are subTLVs left to decode ... for now lets omit them */
            total_length = plen+2;
            break;

        default:
            proto_tree_add_text(tree, tvb, start_offset, 0,
                    "Unknown SAFI (%u) for AFI %u", safi, afi);
            return -1;
        }
        break;

    default:
        proto_tree_add_text(tree, tvb, start_offset, 0,
                "Unknown AFI (%u) value", afi);
        return -1;
    }
    return(total_length);
}

/*
 * Dissect a BGP capability.
 */
static void
dissect_bgp_capability_item(tvbuff_t *tvb, int *p, proto_tree *tree, int ctype, int clen)
{
    proto_tree *subtree;
    proto_item *ti;
    guint8 orfnum;       /* number of ORFs */
    guint8 orftype;      /* ORF Type */
    guint8 orfsendrecv;  /* ORF Send/Receive */
    int    tclen;        /* capability length */
    int    i;

    /* check the capability type */
    switch (ctype) {
    case BGP_CAPABILITY_RESERVED:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      proto_tree_add_text(tree, tvb, *p - 1,
             1, "Capability length: %u %s", clen,
             (clen == 1) ? "byte" : "bytes");
      if (clen != 0) {
          proto_tree_add_text(tree, tvb, *p,
                 clen, "Capability value: Unknown");
      }
      *p += clen;
      break;
    case BGP_CAPABILITY_MULTIPROTOCOL:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      if (clen != 4) {
          proto_tree_add_text(tree, tvb, *p - 1,
                 1, "Capability length: Invalid");
          proto_tree_add_text(tree, tvb, *p,
                 clen, "Capability value: Unknown");
      }
      else {
          proto_tree_add_text(tree, tvb, *p - 1,
                 1, "Capability length: %u %s", clen,
                 (clen == 1) ? "byte" : "bytes");
          ti = proto_tree_add_text(tree, tvb, *p, clen, "Capability value");
          subtree = proto_item_add_subtree(ti, ett_bgp_option);
          /* AFI */
          i = tvb_get_ntohs(tvb, *p);
          proto_tree_add_text(subtree, tvb, *p,
                 2, "Address family identifier: %s (%u)",
                 val_to_str(i, afn_vals, "Unknown"), i);
          *p += 2;
          /* Reserved */
          proto_tree_add_text(subtree, tvb, *p, 1, "Reserved: 1 byte");
          (*p)++;
          /* SAFI */
          i = tvb_get_guint8(tvb, *p);
          proto_tree_add_text(subtree, tvb, *p,
                 1, "Subsequent address family identifier: %s (%u)",
                 val_to_str(i, bgpattr_nlri_safi,
                 i >= 128 ? "Vendor specific" : "Unknown"), i);
          (*p)++;
      }
      break;
    case BGP_CAPABILITY_GRACEFUL_RESTART:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      if (clen < 6) {
          proto_tree_add_text(tree, tvb, *p,
                 clen, "Capability value: Invalid");
      }
      else {
          proto_tree_add_text(tree, tvb, *p - 1,
                 1, "Capability length: %u %s", clen,
             (clen == 1) ? "byte" : "bytes");
          ti = proto_tree_add_text(tree, tvb, *p, clen, "Capability value");
          subtree = proto_item_add_subtree(ti, ett_bgp_option);
          /* Timers */
          i = tvb_get_ntohs(tvb, *p);
          proto_tree_add_text(subtree, tvb, *p,
                 2, "Restart Flags: [%s], Restart Time %us",
                 (i&0x8000) ? "R" : "none", i&0xfff);
          *p += 2;
          tclen = clen - 2;
          /*
           * what follows is alist of AFI/SAFI/flag triplets
           * read it until the TLV ends
           */
          while (tclen >=4) {
            /* AFI */
            i = tvb_get_ntohs(tvb, *p);
            proto_tree_add_text(subtree, tvb, *p,
                     2, "Address family identifier: %s (%u)",
                     val_to_str(i, afn_vals, "Unknown"), i);
            *p += 2;
            /* SAFI */
            i = tvb_get_guint8(tvb, *p);
            proto_tree_add_text(subtree, tvb, *p,
                     1, "Subsequent address family identifier: %s (%u)",
                     val_to_str(i, bgpattr_nlri_safi,
                     i >= 128 ? "Vendor specific" : "Unknown"), i);
            (*p)++;
            /* flags */
            i = tvb_get_guint8(tvb, *p);
            proto_tree_add_text(subtree, tvb, *p, 1,
                 "Preserve forwarding state: %s",
                     (i&0x80) ? "yes" : "no");
            (*p)++;
            tclen-=4;
          }
      }
      *p += clen;
      break;
    case BGP_CAPABILITY_4_OCTET_AS_NUMBER:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      if (clen != 4) {
          proto_tree_add_text(tree, tvb, *p,
                 clen, "Capability value: Invalid");
      }
      else {
          proto_tree_add_text(tree, tvb, *p - 1,
                 1, "Capability length: %u %s", clen,
                 (clen == 1) ? "byte" : "bytes");
          ti = proto_tree_add_text(tree, tvb, *p, clen, "Capability value");
          subtree = proto_item_add_subtree(ti, ett_bgp_option);
          proto_tree_add_text(subtree, tvb, *p, 4,
             "AS number: %d", tvb_get_ntohl(tvb, *p));
      }
      *p += clen;
      break;
    case BGP_CAPABILITY_DYNAMIC_CAPABILITY:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      proto_tree_add_text(tree, tvb, *p - 1, 1,
             "Capability length: %u %s", clen,
             (clen == 1) ? "byte" : "bytes");
      if (clen > 0) {
          ti = proto_tree_add_text(tree, tvb, *p, clen, "Capability value");
          subtree = proto_item_add_subtree(ti, ett_bgp_option);
          for (i = 0; (int)i <= clen; i++) {
            proto_tree_add_text(subtree, tvb, *p, 1,
                 "Capability code: %s (%d)", val_to_str(ctype,
                 capability_vals, "Unknown capability"),
                 tvb_get_guint8(tvb, *p));
            (*p)++;
          }
      }
      break;
    case BGP_CAPABILITY_ROUTE_REFRESH_CISCO:
    case BGP_CAPABILITY_ROUTE_REFRESH:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      if (clen != 0) {
          proto_tree_add_text(tree, tvb, *p,
                 clen, "Capability value: Invalid");
      }
      else {
          proto_tree_add_text(tree, tvb, *p - 1,
                 1, "Capability length: %u %s", clen,
                 (clen == 1) ? "byte" : "bytes");
      }
      *p += clen;
      break;
    case BGP_CAPABILITY_ORF_CISCO:
    case BGP_CAPABILITY_COOPERATIVE_ROUTE_FILTERING:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      proto_tree_add_text(tree, tvb, *p - 1,
           1, "Capability length: %u %s", clen,
           (clen == 1) ? "byte" : "bytes");
      ti = proto_tree_add_text(tree, tvb, *p, clen, "Capability value");
      subtree = proto_item_add_subtree(ti, ett_bgp_option);
      /* AFI */
      i = tvb_get_ntohs(tvb, *p);
      proto_tree_add_text(subtree, tvb, *p,
           2, "Address family identifier: %s (%u)",
             val_to_str(i, afn_vals, "Unknown"), i);
      *p += 2;
      /* Reserved */
      proto_tree_add_text(subtree, tvb, *p, 1, "Reserved: 1 byte");
      (*p)++;
      /* SAFI */
      i = tvb_get_guint8(tvb, *p);
      proto_tree_add_text(subtree, tvb, *p,
           1, "Subsequent address family identifier: %s (%u)",
           val_to_str(i, bgpattr_nlri_safi,
           i >= 128 ? "Vendor specific" : "Unknown"), i);
      (*p)++;
      /* Number of ORFs */
      orfnum = tvb_get_guint8(tvb, *p);
      proto_tree_add_text(subtree, tvb, *p, 1, "Number of ORFs: %u", orfnum);
      (*p)++;
      for (i=0; i<orfnum; i++) {
          /* ORF Type */
          orftype = tvb_get_guint8(tvb, *p);
          proto_tree_add_text(subtree, tvb, *p, 1, "ORF Type: %s (%u)",
             val_to_str(orftype, orf_type_vals,"Unknown"), orftype);
          (*p)++;
          /* Send/Receive */
          orfsendrecv = tvb_get_guint8(tvb, *p);
          proto_tree_add_text(subtree, tvb, *p,
             1, "Send/Receive: %s (%u)",
             val_to_str(orfsendrecv, orf_send_recv_vals,
             "Uknown"), orfsendrecv);
          (*p)++;
      }
      break;
      /* unknown capability */
    default:
      proto_tree_add_text(tree, tvb, *p - 2, 1,
           "Capability code: %s (%d)", val_to_str(ctype,
           capability_vals, "Unknown capability"), ctype);
      proto_tree_add_text(tree, tvb, *p - 2,
           1, "Capability code: %s (%d)",
             ctype >= 128 ? "Private use" : "Unknown", ctype);
      proto_tree_add_text(tree, tvb, *p - 1,
             1, "Capability length: %u %s", clen,
             (clen == 1) ? "byte" : "bytes");
      if (clen != 0) {
          proto_tree_add_text(tree, tvb, *p,
                 clen, "Capability value: Unknown");
      }
      *p += clen;
      break;
    }
}


/*
 * Dissect a BGP OPEN message.
 */
static const value_string community_vals[] = {
      { BGP_COMM_NO_EXPORT,           "NO_EXPORT" },
      { BGP_COMM_NO_ADVERTISE,        "NO_ADVERTISE" },
      { BGP_COMM_NO_EXPORT_SUBCONFED, "NO_EXPORT_SUBCONFED" },
      { 0,                            NULL }
};

static void
dissect_bgp_open(tvbuff_t *tvb, proto_tree *tree)
{
    struct bgp_open bgpo;      /* BGP OPEN message      */
    int             hlen;      /* message length        */
    int             ptype;     /* parameter type        */
    int             plen;      /* parameter length      */
    int             ctype;     /* capability type       */
    int             clen;      /* capability length     */
    int             cend;      /* capabilities end      */
    int             ostart;    /* options start         */
    int             oend;      /* options end           */
    int             p;         /* tvb offset counter    */
    proto_item      *ti;       /* tree item             */
    proto_tree      *subtree;  /* subtree for options   */
    proto_tree      *subtree1; /* subtree for an option */
    proto_tree      *subtree2; /* subtree for an option */

    /* snarf OPEN message */
    tvb_memcpy(tvb, bgpo.bgpo_marker, 0, BGP_MIN_OPEN_MSG_SIZE);
    hlen = g_ntohs(bgpo.bgpo_len);

    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_open, bgpo_version), 1,
      "Version: %u", bgpo.bgpo_version);
    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_open, bgpo_myas), 2,
      "My AS: %u", g_ntohs(bgpo.bgpo_myas));
    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_open, bgpo_holdtime), 2,
      "Hold time: %u", g_ntohs(bgpo.bgpo_holdtime));
    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_open, bgpo_id), 4,
      "BGP identifier: %s", ip_to_str((guint8 *)&bgpo.bgpo_id));
    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_open, bgpo_optlen), 1,
      "Optional parameters length: %u %s", bgpo.bgpo_optlen,
        (bgpo.bgpo_optlen == 1) ? "byte" : "bytes");

    /* optional parameters */
    if (bgpo.bgpo_optlen > 0) {
        /* add a subtree and setup some offsets */
        ostart = BGP_MIN_OPEN_MSG_SIZE;
        ti = proto_tree_add_text(tree, tvb, ostart, bgpo.bgpo_optlen,
             "Optional parameters");
        subtree = proto_item_add_subtree(ti, ett_bgp_options);
        p = ostart;
        oend = p + bgpo.bgpo_optlen;

        /* step through all of the optional parameters */
        while (p < oend) {

            /* grab the type and length */
            ptype = tvb_get_guint8(tvb, p++);
            plen = tvb_get_guint8(tvb, p++);

            /* check the type */
            switch (ptype) {
            case BGP_OPTION_AUTHENTICATION:
                proto_tree_add_text(subtree, tvb, p - 2, 2 + plen,
                    "Authentication information (%u %s)", plen,
                    (plen == 1) ? "byte" : "bytes");
                break;
            case BGP_OPTION_CAPABILITY:
                /* grab the capability code */
              cend = p - 1 + plen;
                ctype = tvb_get_guint8(tvb, p++);
                clen = tvb_get_guint8(tvb, p++);
            ti = proto_tree_add_text(subtree, tvb, p - 4,
                     2 + plen, "Capabilities Advertisement (%u bytes)",
                 2 + plen);
            subtree1 = proto_item_add_subtree(ti, ett_bgp_option);
            proto_tree_add_text(subtree1, tvb, p - 4,
                     1, "Parameter type: Capabilities (2)");
            proto_tree_add_text(subtree1, tvb, p - 3,
                     1, "Parameter length: %u %s", plen,
                     (plen == 1) ? "byte" : "bytes");
            p -= 2;

            /* step through all of the capabilities */
            while (p < cend) {
                ctype = tvb_get_guint8(tvb, p++);
                clen = tvb_get_guint8(tvb, p++);

                ti = proto_tree_add_text(subtree1, tvb, p - 2,
                         2 + clen, "%s (%u %s)", val_to_str(ctype,
                   capability_vals, "Unknown capability"),
                   2 + clen, (clen == 1) ? "byte" : "bytes");
                subtree2 = proto_item_add_subtree(ti, ett_bgp_option);
                dissect_bgp_capability_item(tvb, &p,
                     subtree2, ctype, clen);
            }
                break;
            default:
                proto_tree_add_text(subtree, tvb, p - 2, 2 + plen,
                    "Unknown optional parameter");
                break;
            }
        }
    }
}

/*
 * Dissect a BGP UPDATE message.
 */
static void
dissect_bgp_update(tvbuff_t *tvb, proto_tree *tree)
{
    struct bgp_attr bgpa;                       /* path attributes          */
    guint16         hlen;                       /* message length           */
    gint            o;                          /* packet offset            */
    gint            q;                          /* tmp                      */
    gint            end;                        /* message end              */
    guint16         ext_com;                    /* EXTENDED COMMUNITY type  */
    guint16         len;                        /* tmp                      */
    int             advance;                    /* tmp                      */
    proto_item      *ti;                        /* tree item                */
    proto_tree      *subtree;                   /* subtree for attributes   */
    proto_tree      *subtree2;                  /* subtree for attributes   */
    proto_tree      *subtree3;                  /* subtree for attributes   */
    proto_tree      *subtree4;                  /* subtree for attributes   */
    proto_tree      *as_paths_tree;             /* subtree for AS_PATHs     */
    proto_tree      *as_path_tree;              /* subtree for AS_PATH      */
    proto_tree      *as_path_segment_tree;      /* subtree for AS_PATH segments */
    proto_tree      *communities_tree;          /* subtree for COMMUNITIES  */
    proto_tree      *community_tree;            /* subtree for a community  */
    proto_tree      *cluster_list_tree;         /* subtree for CLUSTER_LIST */
    int             i, j;                       /* tmp                      */
    guint8          length;                     /* AS_PATH length           */
    guint8          type;                       /* AS_PATH type             */
    guint32         as_path_item;               /* item in AS_PATH segment  */
    static GString  *as_path_gstr = NULL;       /* AS_PATH GString          */
    static GString  *communities_gstr = NULL;   /* COMMUNITIES GString      */
    static GString  *cluster_list_gstr = NULL;  /* CLUSTER_LIST GString     */
    static GString  *junk_gbuf = NULL;          /* tmp                      */
    guint8          ipaddr[4];                  /* IPv4 address             */
    guint32         aggregator_as;
    guint16     ssa_type;                 /* SSA T + Type */
    guint16     ssa_len;                  /* SSA TLV Length */
    guint8      ssa_v3_len;               /* SSA L2TPv3 Cookie Length */

    hlen = tvb_get_ntohs(tvb, BGP_MARKER_SIZE);
    o = BGP_HEADER_SIZE;
    if (junk_gbuf == NULL)
      junk_gbuf = g_string_sized_new(0);

    /* check for withdrawals */
    len = tvb_get_ntohs(tvb, o);
    proto_tree_add_text(tree, tvb, o, 2,
      "Unfeasible routes length: %u %s", len, (len == 1) ? "byte" : "bytes");
    o += 2;

    /* parse unfeasible prefixes */
    if (len > 0) {
        ti = proto_tree_add_text(tree, tvb, o, len, "Withdrawn routes:");
      subtree = proto_item_add_subtree(ti, ett_bgp_unfeas);

        /* parse each prefix */
        end = o + len;
        while (o < end) {
            i = decode_prefix4(subtree, hf_bgp_withdrawn_prefix, tvb, o, len,
                "Withdrawn route");
            if (i < 0)
                return;
            o += i;
        }
    }

    /* check for advertisements */
    len = tvb_get_ntohs(tvb, o);
    proto_tree_add_text(tree, tvb, o, 2, "Total path attribute length: %u %s",
            len, (len == 1) ? "byte" : "bytes");

    /* path attributes */
    if (len > 0) {
        ti = proto_tree_add_text(tree, tvb, o + 2, len, "Path attributes");
      subtree = proto_item_add_subtree(ti, ett_bgp_attrs);
      i = 2;
      while (i < len) {
          char    *msg;
          int     off;
          gint    k;
          guint16 alen, tlen, aoff; 
          guint16 af;
            guint8  saf, snpa;
          guint8  nexthop_len;
          guint8  asn_len = 0;

          tvb_memcpy(tvb, (guint8 *)&bgpa, o + i, sizeof(bgpa));
            /* check for the Extended Length bit */
          if (bgpa.bgpa_flags & BGP_ATTR_FLAG_EXTENDED_LENGTH) {
            alen = tvb_get_ntohs(tvb, o + i + sizeof(bgpa));
            aoff = sizeof(bgpa) + 2;
          } else {
            alen = tvb_get_guint8(tvb, o + i + sizeof(bgpa));
            aoff = sizeof(bgpa) + 1;
          }
            tlen = alen;

          /* This is kind of ugly - similar code appears twice, but it
               helps browsing attrs.                                      */
            /* the first switch prints things in the title of the subtree */
          switch (bgpa.bgpa_type) {
          case BGPTYPE_ORIGIN:
            if (tlen != 1)
                goto default_attribute_top;
            msg = val_to_str(tvb_get_guint8(tvb, o + i + aoff), bgpattr_origin, "Unknown");
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  msg, tlen + aoff, (tlen + aoff == 1) ? "byte" :
                        "bytes");
            break;
          case BGPTYPE_AS_PATH:
          case BGPTYPE_NEW_AS_PATH:
                /* (o + i + aoff) =
                   (o + current attribute + aoff bytes to first tuple) */
                q = o + i + aoff;
                end = q + tlen;
                /* must be freed by second switch!                         */
                /* "tlen * 11" (10 digits + space) should be a good estimate
                   of how long the AS path string could be                 */
            if (as_path_gstr == NULL)
                as_path_gstr = g_string_sized_new((tlen + 1) * 11);
                if (as_path_gstr == NULL) break;
                g_string_truncate(as_path_gstr, 0);

            /* estimate the length of the AS number */
            if (bgpa.bgpa_type == BGPTYPE_NEW_AS_PATH) 
                asn_len = 4;
            else {
                if (bgp_asn_len == 0) {
                  k = q;
                  while (k < end) {
                      k++;
                      length = tvb_get_guint8(tvb, k++);
                      k += length * 2;
                  }
                  asn_len = (k == end) ? 2 : 4;
                }
                else {
                  asn_len = bgp_asn_len;
                }
            }

                /* snarf each AS path */
                while (q < end) {
                type = tvb_get_guint8(tvb, q++);
                if (as_path_gstr->len > 1 &&
                  as_path_gstr->str[as_path_gstr->len - 1] != ' ')
                  g_string_append_c(as_path_gstr, ' ');
                    if (type == AS_SET) {
                        g_string_append_c(as_path_gstr, '{');
                    }
                    else if (type == AS_CONFED_SET) {
                  g_string_append_c(as_path_gstr, '[');
                    }
                    else if (type == AS_CONFED_SEQUENCE) {
                  g_string_append_c(as_path_gstr, '(');
                }
                length = tvb_get_guint8(tvb, q++);

                    /* snarf each value in path */
                    for (j = 0; j < length; j++) {
                  g_string_sprintfa(as_path_gstr, "%u%s",
                        (asn_len == 2) ?
                        tvb_get_ntohs(tvb, q) : tvb_get_ntohl(tvb, q),
                        (type == AS_SET || type == AS_CONFED_SET) ?
                        ", " : " ");
                        q += asn_len;
                    }

                    /* cleanup end of string */
                    if (type == AS_SET) {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 2);
                  g_string_append_c(as_path_gstr, '}');
                    }
                    else if (type == AS_CONFED_SET) {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 2);
                  g_string_append_c(as_path_gstr, ']');
                    }
                    else if (type == AS_CONFED_SEQUENCE) {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 1);
                  g_string_append_c(as_path_gstr, ')');
                    }
                    else {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 1);
                    }
                }

                /* check for empty AS_PATH */
            if (tlen == 0)
                    g_string_sprintf(as_path_gstr, "empty");

            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                        "%s: %s (%u %s)",
                        val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                        as_path_gstr->str, tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
            break;
          case BGPTYPE_NEXT_HOP:
            if (tlen != 4)
                goto default_attribute_top;
            tvb_memcpy(tvb, ipaddr, o + i + aoff, 4);
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  ip_to_str(ipaddr), tlen + aoff, (tlen + aoff == 1)
                        ? "byte" : "bytes");
            break;
          case BGPTYPE_MULTI_EXIT_DISC:
            if (tlen != 4)
                goto default_attribute_top;
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %u (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  tvb_get_ntohl(tvb, o + i + aoff), tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
            break;
          case BGPTYPE_LOCAL_PREF:
            if (tlen != 4)
                goto default_attribute_top;
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %u (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  tvb_get_ntohl(tvb, o + i + aoff), tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
            break;
            case BGPTYPE_ATOMIC_AGGREGATE:
                if (tlen != 0)
                goto default_attribute_top;
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  tlen + aoff, (tlen + aoff == 1) ? "byte" : "bytes");
            break;
          case BGPTYPE_AGGREGATOR:
            if (tlen != 6 && tlen != 8)
                goto default_attribute_top;
          case BGPTYPE_NEW_AGGREGATOR:
                if (bgpa.bgpa_type == BGPTYPE_NEW_AGGREGATOR && tlen != 8)
                goto default_attribute_top;
            asn_len = tlen - 4;
            tvb_memcpy(tvb, ipaddr, o + i + aoff + asn_len, 4);
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: AS: %u origin: %s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  (asn_len == 2) ? tvb_get_ntohs(tvb, o + i + aoff) :
                  tvb_get_ntohl(tvb, o + i + aoff),
                  ip_to_str(ipaddr), tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
            break;
            case BGPTYPE_COMMUNITIES:
            if (tlen % 4 != 0)
                goto default_attribute_top;

                /* (o + i + aoff) =
                   (o + current attribute + aoff bytes to first tuple) */
                q = o + i + aoff;
                end = q + tlen;
                /* must be freed by second switch!                          */
                /* "tlen * 12" (5 digits, a :, 5 digits + space ) should be
                   a good estimate of how long the communities string could
                   be                                                       */
            if (communities_gstr == NULL)
                communities_gstr = g_string_sized_new((tlen + 1) * 12);
                if (communities_gstr == NULL) break;
            g_string_truncate(communities_gstr, 0);

                /* snarf each community */
                while (q < end) {
                    /* check for well-known communities */
                if (tvb_get_ntohl(tvb, q) == BGP_COMM_NO_EXPORT)
                        g_string_append(communities_gstr, "NO_EXPORT ");
                else if (tvb_get_ntohl(tvb, q) == BGP_COMM_NO_ADVERTISE)
                        g_string_append(communities_gstr, "NO_ADVERTISE ");
                else if (tvb_get_ntohl(tvb, q) == BGP_COMM_NO_EXPORT_SUBCONFED)
                        g_string_append(communities_gstr, "NO_EXPORT_SUBCONFED ");
                    else {
                        g_string_sprintfa(communities_gstr, "%u:%u ",
                            tvb_get_ntohs(tvb, q),
                                tvb_get_ntohs(tvb, q + 2));
                    }
                    q += 4;
                }
                /* cleanup end of string */
                g_string_truncate(communities_gstr, communities_gstr->len - 1);

            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                        communities_gstr->str, tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
              break;
          case BGPTYPE_ORIGINATOR_ID:
            if (tlen != 4)
                goto default_attribute_top;
            tvb_memcpy(tvb, ipaddr, o + i + aoff, 4);
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  ip_to_str(ipaddr), tlen + aoff, (tlen + aoff == 1)
                        ? "byte" : "bytes");
            break;
          case BGPTYPE_CLUSTER_LIST:
            if (tlen % 4 != 0)
                goto default_attribute_top;

                /* (o + i + aoff) =
                   (o + current attribute + aoff bytes to first tuple) */
                q = o + i + aoff;
                end = q + tlen;
                /* must be freed by second switch!                          */
                /* "tlen * 16" (12 digits, 3 dots + space ) should be
                   a good estimate of how long the cluster_list string could
                   be                                                       */
            if (cluster_list_gstr == NULL)
                    cluster_list_gstr = g_string_sized_new((tlen + 1) * 16);
                if (cluster_list_gstr == NULL) break;
                g_string_truncate(cluster_list_gstr, 0);

                /* snarf each cluster list */
            tvb_memcpy(tvb, ipaddr, q, 4);
                while (q < end) {
                    g_string_sprintfa(cluster_list_gstr, "%s ", ip_to_str(ipaddr));
                    q += 4;
                }
                /* cleanup end of string */
                g_string_truncate(cluster_list_gstr, cluster_list_gstr->len - 1);

            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s: %s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                        cluster_list_gstr->str, tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
            break;
          case BGPTYPE_EXTENDED_COMMUNITY:
            if (tlen %8 != 0)
                break;
                ti = proto_tree_add_text(subtree,tvb,o+i,tlen+aoff,
                        "%s: (%u %s)",
                        val_to_str(bgpa.bgpa_type,bgpattr_type,"Unknown"),
                        tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
                break;
            case BGPTYPE_SAFI_SPECIFIC_ATTR:
                ti = proto_tree_add_text(subtree,tvb,o+i,tlen+aoff,
                        "%s: (%u %s)",
                        val_to_str(bgpa.bgpa_type,bgpattr_type,"Unknown"),
                        tlen + aoff,
                        (tlen + aoff == 1) ? "byte" : "bytes");
                break;

          default:
          default_attribute_top:
            ti = proto_tree_add_text(subtree, tvb, o + i, tlen + aoff,
                  "%s (%u %s)",
                  val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                  tlen + aoff, (tlen + aoff == 1) ? "byte" : "bytes");
          } /* end of first switch */
          subtree2 = proto_item_add_subtree(ti, ett_bgp_attr);

            /* figure out flags */
          g_string_truncate(junk_gbuf, 0);
            if (bgpa.bgpa_flags & BGP_ATTR_FLAG_OPTIONAL) {
                 g_string_append(junk_gbuf, "Optional, ");
            }
            else {
                 g_string_append(junk_gbuf, "Well-known, ");
            }
            if (bgpa.bgpa_flags & BGP_ATTR_FLAG_TRANSITIVE) {
                 g_string_append(junk_gbuf, "Transitive, ");
            }
            else {
                 g_string_append(junk_gbuf, "Non-transitive, ");
            }
            if (bgpa.bgpa_flags & BGP_ATTR_FLAG_PARTIAL) {
                 g_string_append(junk_gbuf, "Partial, ");
            }
            else {
                 g_string_append(junk_gbuf, "Complete, ");
            }
            if (bgpa.bgpa_flags & BGP_ATTR_FLAG_EXTENDED_LENGTH) {
                 g_string_append(junk_gbuf, "Extended Length, ");
            }
            /* stomp last ", " */
          g_string_truncate(junk_gbuf, junk_gbuf->len - 2);
          ti = proto_tree_add_text(subtree2, tvb,
                o + i + offsetof(struct bgp_attr, bgpa_flags), 1,
                "Flags: 0x%02x (%s)", bgpa.bgpa_flags, junk_gbuf->str);
          subtree3 = proto_item_add_subtree(ti, ett_bgp_attr_flags);

            /* add flag bitfield subtrees */
          proto_tree_add_text(subtree3, tvb,
                o + i + offsetof(struct bgp_attr, bgpa_flags), 1,
                "%s", decode_boolean_bitfield(bgpa.bgpa_flags,
                  BGP_ATTR_FLAG_OPTIONAL, 8, "Optional", "Well-known"));
          proto_tree_add_text(subtree3, tvb,
                o + i + offsetof(struct bgp_attr, bgpa_flags), 1,
                "%s", decode_boolean_bitfield(bgpa.bgpa_flags,
                  BGP_ATTR_FLAG_TRANSITIVE, 8, "Transitive",
                        "Non-transitive"));
          proto_tree_add_text(subtree3, tvb,
                o + i + offsetof(struct bgp_attr, bgpa_flags), 1,
                "%s", decode_boolean_bitfield(bgpa.bgpa_flags,
                  BGP_ATTR_FLAG_PARTIAL, 8, "Partial", "Complete"));
          proto_tree_add_text(subtree3, tvb,
                o + i + offsetof(struct bgp_attr, bgpa_flags), 1,
                "%s", decode_boolean_bitfield(bgpa.bgpa_flags,
                  BGP_ATTR_FLAG_EXTENDED_LENGTH, 8, "Extended length",
                        "Regular length"));

          proto_tree_add_text(subtree2, tvb,
                o + i + offsetof(struct bgp_attr, bgpa_type), 1,
                "Type code: %s (%u)",
                val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"),
                bgpa.bgpa_type);

            proto_tree_add_text(subtree2, tvb, o + i + sizeof(bgpa),
                    aoff - sizeof(bgpa), "Length: %d %s", tlen,
                    (tlen == 1) ? "byte" : "bytes");

            /* the second switch prints things in the actual subtree of each
               attribute                                                     */
          switch (bgpa.bgpa_type) {
          case BGPTYPE_ORIGIN:
            if (tlen != 1) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Origin (invalid): %u %s", tlen,
                             (tlen == 1) ? "byte" : "bytes");
            } else {
                proto_tree_add_item(subtree2, hf_bgp_origin, tvb,
                      o + i + aoff, 1, FALSE);
            }
            break;
          case BGPTYPE_AS_PATH:
          case BGPTYPE_NEW_AS_PATH:
              ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                        "AS path: %s", as_path_gstr->str);
              as_paths_tree = proto_item_add_subtree(ti, ett_bgp_as_paths);

                /* (o + i + aoff) =
                   (o + current attribute + aoff bytes to first tuple) */
                q = o + i + aoff;
                end = q + tlen;

                /* snarf each AS path tuple, we have to step through each one
                   again to make a separate subtree so we can't just reuse
                   as_path_gstr from above */
            /* XXX - Can we use some g_string*() trickery instead, e.g. 
               g_string_erase()? */
                while (q < end) {
                g_string_truncate(as_path_gstr, 0);
                    type = tvb_get_guint8(tvb, q++);
                    if (type == AS_SET) {
                        g_string_append_c(as_path_gstr, '{');
                    }
                    else if (type == AS_CONFED_SET) {
                        g_string_append_c(as_path_gstr, '[');
                    }
                    else if (type == AS_CONFED_SEQUENCE) {
                        g_string_append_c(as_path_gstr, '(');
                    }
                    length = tvb_get_guint8(tvb, q++);

                    /* snarf each value in path */
                    for (j = 0; j < length; j++) {
                  g_string_sprintfa(as_path_gstr, "%u%s",
                        (asn_len == 2) ? 
                        tvb_get_ntohs(tvb, q) : tvb_get_ntohl(tvb, q),
                                (type == AS_SET || type == AS_CONFED_SET) ? ", " : " ");
                        q += asn_len;
                    }

                    /* cleanup end of string */
                    if (type == AS_SET) {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 2);
                  g_string_append_c(as_path_gstr, '}');
                    }
                    else if (type == AS_CONFED_SET) {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 2);
                  g_string_append_c(as_path_gstr, ']');
                    }
                    else if (type == AS_CONFED_SEQUENCE) {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 1);
                  g_string_append_c(as_path_gstr, ')');
                    }
                    else {
                  g_string_truncate(as_path_gstr, as_path_gstr->len - 1);
                    }

                    /* length here means number of ASs, ie length * 2 bytes */
                  ti = proto_tree_add_text(as_paths_tree, tvb,
                            q - length * asn_len - 2,
                            length * asn_len + 2, "AS path segment: %s", as_path_gstr->str);
                  as_path_tree = proto_item_add_subtree(ti, ett_bgp_as_paths);
                  proto_tree_add_text(as_path_tree, tvb, q - length * asn_len - 2,
                            1, "Path segment type: %s (%u)",
                            val_to_str(type, as_segment_type, "Unknown"), type);
                  proto_tree_add_text(as_path_tree, tvb, q - length * asn_len - 1,
                            1, "Path segment length: %u %s", length,
                            (length == 1) ? "AS" : "ASs");

                    /* backup and reprint path segment value(s) only */
                    q -= asn_len * length;
                    ti = proto_tree_add_text(as_path_tree, tvb, q,
                            length * asn_len, "Path segment value:");
                    as_path_segment_tree = proto_item_add_subtree(ti,
                            ett_bgp_as_path_segments);
                    for (j = 0; j < length; j++) {
                  as_path_item = (asn_len == 2) ? 
                        tvb_get_ntohs(tvb, q) : tvb_get_ntohl(tvb, q);
                  proto_item_append_text(ti, " %u", as_path_item);
                  proto_tree_add_uint_hidden(as_path_tree, hf_bgp_as_path, tvb,
                      q, asn_len, as_path_item);
                        q += asn_len;
                    }
                }

            break;
          case BGPTYPE_NEXT_HOP:
            if (tlen != 4) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Next hop (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
            } else {
                proto_tree_add_item(subtree2, hf_bgp_next_hop, tvb,
                      o + i + aoff, tlen, FALSE);
            }
            break;
          case BGPTYPE_MULTI_EXIT_DISC:
            if (tlen != 4) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Multiple exit discriminator (invalid): %u %s",
                      tlen, (tlen == 1) ? "byte" : "bytes");
            } else {
                proto_tree_add_item(subtree2, hf_bgp_multi_exit_disc, tvb,
                      o + i + aoff, tlen, FALSE);
            }
            break;
          case BGPTYPE_LOCAL_PREF:
            if (tlen != 4) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Local preference (invalid): %u %s", tlen,
                             (tlen == 1) ? "byte" : "bytes");
            } else {
                proto_tree_add_item(subtree2, hf_bgp_local_pref, tvb,
                      o + i + aoff, tlen, FALSE);
            }
            break;
          case BGPTYPE_ATOMIC_AGGREGATE:
            if (tlen != 0) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Atomic aggregate (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
                }
            break;
          case BGPTYPE_AGGREGATOR:
            if (tlen != 6 && tlen != 8) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Aggregator (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
                break;
            }
          case BGPTYPE_NEW_AGGREGATOR:
                if (bgpa.bgpa_type == BGPTYPE_NEW_AGGREGATOR && tlen != 8)
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Aggregator (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
            else {
                asn_len = tlen - 4;
                aggregator_as = (asn_len == 2) ?
                      tvb_get_ntohs(tvb, o + i + aoff) :
                      tvb_get_ntohl(tvb, o + i + aoff);
                proto_tree_add_uint(subtree2, hf_bgp_aggregator_as, tvb,
                      o + i + aoff, asn_len, aggregator_as);
                proto_tree_add_item(subtree2, hf_bgp_aggregator_origin, tvb,
                    o + i + aoff + asn_len, 4, FALSE);
            }
            break;
            case BGPTYPE_COMMUNITIES:
            if (tlen % 4 != 0) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Communities (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
                    break;
                }

                ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                        "Communities: %s", communities_gstr->str);
                communities_tree = proto_item_add_subtree(ti,
                        ett_bgp_communities);

                /* (o + i + aoff) =
                   (o + current attribute + aoff bytes to first tuple) */
                q = o + i + aoff;
                end = q + tlen;

                /* snarf each community */
                while (q < end) {
                    /* check for reserved values */
                guint32 community = tvb_get_ntohl(tvb, q);
                if ((community & 0xFFFF0000) == FOURHEX0 ||
                     (community & 0xFFFF0000) == FOURHEXF) {
                    proto_tree_add_text(communities_tree, tvb,
                               q - 3 + aoff, 4,
                               "Community: %s (0x%08x)",
                               val_to_str(community, community_vals, "(reserved)"),
                               community);
                    }
                    else {
                        ti = proto_tree_add_text(communities_tree, tvb,
                                q - 3 + aoff, 4, "Community: %u:%u",
                                tvb_get_ntohs(tvb, q), tvb_get_ntohs(tvb, q + 2));
                        community_tree = proto_item_add_subtree(ti,
                            ett_bgp_communities);
                        proto_tree_add_item(community_tree, hf_bgp_community_as,
                            tvb, q - 3 + aoff, 2, FALSE);
                        proto_tree_add_item(community_tree, hf_bgp_community_value,
                            tvb, q - 1 + aoff, 2, FALSE);
                    }

                    q += 4;
                }

            break;
          case BGPTYPE_ORIGINATOR_ID:
            if (tlen != 4) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Originator identifier (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
            } else {
                proto_tree_add_item(subtree2, hf_bgp_originator_id, tvb,
                      o + i + aoff, tlen, FALSE);
            }
            break;
         case BGPTYPE_MP_REACH_NLRI:
            /*
             * RFC 2545 specifies that there may be more than one
             * address in the MP_REACH_NLRI attribute in section
             * 3, "Constructing the Next Hop field".
             *
             * Yes, RFC 2858 says you can't do that, and, yes, RFC
             * 2858 obsoletes RFC 2283, which says you can do that,
             * but that doesn't mean we shouldn't dissect packets
             * that conform to RFC 2283 but not RFC 2858, as some
             * device on the network might implement the 2283-style
             * BGP extensions rather than RFC 2858-style extensions.
             */
            af = tvb_get_ntohs(tvb, o + i + aoff);
            proto_tree_add_text(subtree2, tvb, o + i + aoff, 2,
                "Address family: %s (%u)",
                val_to_str(af, afn_vals, "Unknown"), af);
                saf = tvb_get_guint8(tvb, o + i + aoff + 2) ;
            proto_tree_add_text(subtree2, tvb, o + i + aoff + 2, 1,
                "Subsequent address family identifier: %s (%u)",
                val_to_str(saf, bgpattr_nlri_safi, saf >= 128 ? "Vendor specific" : "Unknown"),
                saf);
            nexthop_len = tvb_get_guint8(tvb, o + i + aoff + 3);
            ti = proto_tree_add_text(subtree2, tvb, o + i + aoff + 3,
                    nexthop_len + 1,
                  "Next hop network address (%d %s)",
                  nexthop_len, plurality(nexthop_len, "byte", "bytes"));
            subtree3 = proto_item_add_subtree(ti, ett_bgp_mp_nhna);
                if (af != AFNUM_INET && af != AFNUM_INET6 && af != AFNUM_L2VPN) {
                    /*
                     * The addresses don't contain lengths, so if we
                     * don't understand the address family type, we
                     * cannot parse the subsequent addresses as we
                     * don't know how long they are.
                     */
                proto_tree_add_text(subtree3, tvb, o + i + aoff + 4,
                  nexthop_len, "Unknown Address Family");
                } else {
                j = 0;
                while (j < nexthop_len) {
                  advance = mp_addr_to_str(af, saf, tvb, o + i + aoff + 4 + j,
                        junk_gbuf) ;
                  if (advance == 0) /* catch if this is a unknown AFI type*/
                        break;
                  if (j + advance > nexthop_len)
                        break;
                  proto_tree_add_text(subtree3, tvb,o + i + aoff + 4 + j,
                        advance, "Next hop: %s (%u)", junk_gbuf->str, advance);
                  j += advance;
                }
            }
                tlen -= nexthop_len + 4;
                aoff += nexthop_len + 4 ;

                off = 0;
            snpa = tvb_get_guint8(tvb, o + i + aoff);
            ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, 1,
                  "Subnetwork points of attachment: %u", snpa);
            off++;
            if (snpa) {
                    subtree3 = proto_item_add_subtree(ti, ett_bgp_mp_snpa);
                        for (/*nothing*/; snpa > 0; snpa--) {
                            proto_tree_add_text(subtree3, tvb, o + i + aoff + off, 1,
                                  "SNPA length: %u", tvb_get_guint8(tvb, o + i + aoff + off));
                            off++;
                            proto_tree_add_text(subtree3, tvb, o + i + aoff + off,
                          tvb_get_guint8(tvb, o + i + aoff + off - 1),
                                  "SNPA (%u %s)", tvb_get_guint8(tvb, o + i + aoff + off - 1),
                                        (tvb_get_guint8(tvb, o + i + aoff + off - 1) == 1) ? "byte" : "bytes");
                            off += tvb_get_guint8(tvb, o + i + aoff + off - 1);
                    }
                }
                tlen -= off;
            aoff += off;

            ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                  "Network layer reachability information (%u %s)",
                  tlen, (tlen == 1) ? "byte" : "bytes");
            if (tlen)  {
                  subtree3 = proto_item_add_subtree(ti,ett_bgp_mp_reach_nlri);
                if (af != AFNUM_INET && af != AFNUM_INET6 && af != AFNUM_L2VPN) {
                  proto_tree_add_text(subtree3, tvb, o + i + aoff,
                        tlen, "Unknown Address Family");
                } else {
                          while (tlen > 0) {
                                advance = decode_prefix_MP(subtree3,
                                    hf_bgp_mp_reach_nlri_ipv4_prefix,
                                    -1,
                                    af, saf,
                                    tvb, o + i + aoff, "MP Reach NLRI");
                        if (advance < 0)
                            break;
                            tlen -= advance;
                            aoff += advance;
                        }
                }
                }
            break;
         case BGPTYPE_MP_UNREACH_NLRI:
              af = tvb_get_ntohs(tvb, o + i + aoff);
            proto_tree_add_text(subtree2, tvb, o + i + aoff, 2,
                "Address family: %s (%u)",
                val_to_str(af, afn_vals, "Unknown"), af);
                saf = tvb_get_guint8(tvb, o + i + aoff + 2) ;
            proto_tree_add_text(subtree2, tvb, o + i + aoff + 2, 1,
                "Subsequent address family identifier: %s (%u)",
                val_to_str(saf, bgpattr_nlri_safi, saf >= 128 ? "Vendor specific" : "Unknown"),
                saf);
            ti = proto_tree_add_text(subtree2, tvb, o + i + aoff + 3,
                  tlen - 3, "Withdrawn routes (%u %s)", tlen - 3,
                        (tlen - 3 == 1) ? "byte" : "bytes");

            tlen -= 3;
            aoff += 3;
            if (tlen > 0) {
                    subtree3 = proto_item_add_subtree(ti,ett_bgp_mp_unreach_nlri);

                    while (tlen > 0) {
                        advance = decode_prefix_MP(subtree3,
                                hf_bgp_mp_unreach_nlri_ipv4_prefix,
                                -1,
                                af, saf,
                                tvb, o + i + aoff, "MP Unreach NLRI");
                        if (advance < 0)
                            break;
                        tlen -= advance;
                        aoff += advance;
                    }
                }
                break;
          case BGPTYPE_CLUSTER_LIST:
            if (tlen % 4 != 0) {
                proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                      "Cluster list (invalid): %u %s", tlen,
                            (tlen == 1) ? "byte" : "bytes");
                    break;
                }

                ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                        "Cluster list: %s", cluster_list_gstr->str);
                cluster_list_tree = proto_item_add_subtree(ti,
                        ett_bgp_cluster_list);

                /* (o + i + aoff) =
                   (o + current attribute + aoff bytes to first tuple) */
                q = o + i + aoff;
                end = q + tlen;

                /* snarf each cluster identifier */
                while (q < end) {
                proto_tree_add_item(cluster_list_tree, hf_bgp_cluster_list,
                      tvb, q - 3 + aoff, 4, FALSE);
                    q += 4;
                }

            break;
          case BGPTYPE_EXTENDED_COMMUNITY:
            if (tlen %8 != 0) {
                        proto_tree_add_text(subtree3, tvb, o + i + aoff, tlen, "Extended community (invalid) : %u %s", tlen,
                                (tlen == 1) ? "byte" : "bytes") ;
                } else {
                        q = o + i + aoff ;
                        end = o + i + aoff + tlen ;
                        ti = proto_tree_add_text(subtree2,tvb,q,tlen, "Carried Extended communities");
                        subtree3 = proto_item_add_subtree(ti,ett_bgp_extended_communities) ;

                        while (q < end) {
                            ext_com = tvb_get_ntohs(tvb,q) ;
                            g_string_sprintf(junk_gbuf, "%s",
                                                  val_to_str(ext_com,bgpext_com_type,"Unknown"));
                            switch (ext_com) {
                            case BGP_EXT_COM_RT_0:
                            case BGP_EXT_COM_RT_2:
                            case BGP_EXT_COM_RO_0:
                            case BGP_EXT_COM_RO_2:
                                g_string_sprintfa(junk_gbuf, ": %u%s%d",
                                                       tvb_get_ntohs(tvb,q+2),":",tvb_get_ntohl(tvb,q+4));
                                proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);
                                break ;
                            case BGP_EXT_COM_RT_1:
                            case BGP_EXT_COM_RO_1:
                                tvb_memcpy(tvb,ipaddr,q+2,4);
                                g_string_sprintfa(junk_gbuf, ": %s%s%u",
                                                       ip_to_str(ipaddr),":",tvb_get_ntohs(tvb,q+6));
                                proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);
                                break;
                            case BGP_EXT_COM_VPN_ORIGIN:
                            case BGP_EXT_COM_OSPF_RID:
                                tvb_memcpy(tvb,ipaddr,q+2,4);
                                g_string_sprintfa(junk_gbuf, ": %s", ip_to_str(ipaddr));
                                proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);
                                break;
                            case BGP_EXT_COM_OSPF_RTYPE:
                                tvb_memcpy(tvb,ipaddr,q+2,4);
                                g_string_sprintfa(junk_gbuf, ": Area: %s, Type: %s", ip_to_str(ipaddr),
                                         val_to_str(tvb_get_guint8(tvb,q+6),bgpext_ospf_rtype,"Unknown"));
                        /* print OSPF Metric type if selected */
                        /* always print E2 even if not external route -- receiving router should ignore */
                                if ( (tvb_get_guint8(tvb,q+7)) & BGP_OSPF_RTYPE_METRIC_TYPE ) {
                                    g_string_sprintfa(junk_gbuf," E2");
                                } else if (tvb_get_guint8(tvb,q+6)==(BGP_OSPF_RTYPE_EXT ||BGP_OSPF_RTYPE_NSSA ) ) {
                                    g_string_sprintfa(junk_gbuf," E1");
                                } else {
                            g_string_sprintfa(junk_gbuf,", no options");
                        }
                                proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);
                                break;
                            case BGP_EXT_COM_LINKBAND:
                                tvb_memcpy(tvb,ipaddr,q+2,4); /* need to check on IEEE format on all platforms */
                                g_string_sprintfa(junk_gbuf, ": %.3f Mbps",
                                                       ((double)*ipaddr)*8/1000000);
                                proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);
                                break;
                            case BGP_EXT_COM_L2INFO:
                                g_string_sprintfa(junk_gbuf,
                                                       ": %s, Control Flags: %s%s%s%s%s, MTU: %u %s",
                                                       val_to_str(tvb_get_guint8(tvb,q+2),bgp_l2vpn_encaps,"Unknown"),
                                                       tvb_get_guint8(tvb,q+3) ? "" : "none",
                                                       tvb_get_ntohs(tvb,q+3)&0x08 ? "Q" : "",
                                                       tvb_get_ntohs(tvb,q+3)&0x04 ? "F" : "",
                                                       tvb_get_ntohs(tvb,q+3)&0x02 ? "C" : "",
                                                       tvb_get_ntohs(tvb,q+3)&0x01 ? "S" : "",
                                                       tvb_get_ntohs(tvb,q+4),
                                                       tvb_get_ntohs(tvb,q+4)==1 ? "byte" : "bytes");
                                ti = proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);

                                subtree4 = proto_item_add_subtree(ti,ett_bgp_extended_communities) ;
                                proto_tree_add_text(subtree4,tvb,q+2,1, "Encapsulation: %s",
                                                         val_to_str(tvb_get_guint8(tvb,q+2),bgp_l2vpn_encaps,"Unknown"));
                                proto_tree_add_text(subtree4,tvb,q+3,1, "Control Flags: %s%sControl Word %s required, Sequenced delivery %s required",
                                                    tvb_get_ntohs(tvb,q+3)&0x08 ? "Q flag (Reserved) set" : "",
                                                    tvb_get_ntohs(tvb,q+3)&0x04 ? "F flag (reserved) set" : "",
                                                    tvb_get_ntohs(tvb,q+3)&0x02 ? "is" : "not",
                                                    tvb_get_ntohs(tvb,q+3)&0x01 ? "is" : "not");
                                proto_tree_add_text(subtree4,tvb,q+4,2, "MTU: %u %s",
                                                    tvb_get_ntohs(tvb,q+4),
                                                    tvb_get_ntohs(tvb,q+4)==1 ? "byte" : "bytes");
                                break;
                            default:
                                proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_gbuf->str);
                                break ;
                            }
                            q = q + 8 ;
                        }
                }
                break;
          case BGPTYPE_SAFI_SPECIFIC_ATTR:
            q = o + i + aoff;
            end = o + i + aoff + tlen ;

            while(q < end) {
                ssa_type = tvb_get_ntohs(tvb, q) & BGP_SSA_TYPE;
                ssa_len = tvb_get_ntohs(tvb, q + 2);

                ti = proto_tree_add_text(subtree2, tvb, q, MIN(ssa_len + 4, end - q),
                      "%s Information",
                      val_to_str(ssa_type, bgp_ssa_type, "Unknown SSA"));
                subtree3 = proto_item_add_subtree(ti, ett_bgp_ssa);

                proto_tree_add_item(subtree3, hf_bgp_ssa_t, tvb,
                      q, 1, FALSE);
                proto_tree_add_item_hidden(subtree3, hf_bgp_ssa_type, tvb,
                      q, 2, FALSE);
                proto_tree_add_text(subtree3, tvb, q, 2,
                      "Type: %s", val_to_str(ssa_type, bgp_ssa_type, "Unknown"));
                if ((ssa_len == 0) || (q + ssa_len > end)) {
                  proto_tree_add_text(subtree3, tvb, q + 2, end - q - 2,
                        "Invalid Length of %u", ssa_len);
                  break;
                }
                proto_tree_add_item(subtree3, hf_bgp_ssa_len, tvb,
                      q + 2, 2, FALSE);

                switch(ssa_type){
                case BGP_SSA_L2TPv3:
                          proto_tree_add_item(subtree3, hf_bgp_ssa_l2tpv3_pref, tvb,
                                  q + 4, 2, FALSE);

                      ti = proto_tree_add_text(subtree3, tvb, q + 6, 1, "Flags");
                      subtree4 = proto_item_add_subtree(ti, ett_bgp_ssa_subtree) ;
                            proto_tree_add_item(subtree4, hf_bgp_ssa_l2tpv3_s, tvb,
                                    q + 6, 1, FALSE);
                            proto_tree_add_item(subtree4, hf_bgp_ssa_l2tpv3_unused, tvb,
                                    q + 6, 1, FALSE);

                      ssa_v3_len = tvb_get_guint8(tvb, q + 7);
                      if (ssa_v3_len + 8 == ssa_len){
                        proto_tree_add_item(subtree3, hf_bgp_ssa_l2tpv3_cookie_len, tvb,
                              q + 7, 1, FALSE);
                      } else {
                        proto_tree_add_text(subtree3, tvb, q + 7, 1,
                              "Invalid Cookie Length of %u", ssa_v3_len);
                        break;
                      }
                            proto_tree_add_item(subtree3, hf_bgp_ssa_l2tpv3_session_id, tvb,
                                    q + 8, 4, FALSE);
                      if (ssa_v3_len)
                                  proto_tree_add_item(subtree3, hf_bgp_ssa_l2tpv3_cookie, tvb,
                                          q + 12, ssa_v3_len, FALSE);
                      break;
                case BGP_SSA_mGRE:
                case BGP_SSA_IPSec:
                case BGP_SSA_MPLS:
                default:
                      proto_tree_add_item(subtree3, hf_bgp_ssa_value, tvb,
                            q + 4, ssa_len, FALSE);
                      break;
                }
                q = q + ssa_len + 4; /* 4 from type and length */
            }
            break;

          default:
            proto_tree_add_text(subtree2, tvb, o + i + aoff, tlen,
                  "Unknown (%d %s)", tlen, (tlen == 1) ? "byte" :
                        "bytes");
            break;
          } /* end of second switch */

          i += alen + aoff;
      }

        o += 2 + len;

        /* NLRI */
        len = hlen - o;

        /* parse prefixes */
        if (len > 0) {
            ti = proto_tree_add_text(tree, tvb, o, len,
                   "Network layer reachability information: %u %s", len,
                   (len == 1) ? "byte" : "bytes");
          subtree = proto_item_add_subtree(ti, ett_bgp_nlri);
            end = o + len;
            while (o < end) {
            i = decode_prefix4(subtree, hf_bgp_nlri_prefix, tvb, o, 0,
                "NLRI");
                if (i < 0)
                    return;
                o += i;
            }
        }
    }
}

/*
 * Dissect a BGP NOTIFICATION message.
 */
static void
dissect_bgp_notification(tvbuff_t *tvb, proto_tree *tree)
{
    struct bgp_notification bgpn;   /* BGP NOTIFICATION message */
    int                     hlen;   /* message length           */
    char                    *p;     /* string pointer           */

    /* snarf message */
    tvb_memcpy(tvb, bgpn.bgpn_marker, 0, BGP_MIN_NOTIFICATION_MSG_SIZE);
    hlen = g_ntohs(bgpn.bgpn_len);

    /* print error code */
    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_notification, bgpn_major), 1,
      "Error code: %s (%u)",
      val_to_str(bgpn.bgpn_major, bgpnotify_major, "Unknown"),
      bgpn.bgpn_major);

    /* print error subcode */
    if (bgpn.bgpn_major < array_length(bgpnotify_minor)
     && bgpnotify_minor[bgpn.bgpn_major] != NULL) {
      p = val_to_str(bgpn.bgpn_minor, bgpnotify_minor[bgpn.bgpn_major],
          "Unknown");
    } else if (bgpn.bgpn_minor == 0)
      p = "Unspecified";
    else
        p = "Unknown";
    proto_tree_add_text(tree, tvb,
      offsetof(struct bgp_notification, bgpn_minor), 1,
      "Error subcode: %s (%u)", p, bgpn.bgpn_minor);

    /* only print if there is optional data */
    if (hlen > BGP_MIN_NOTIFICATION_MSG_SIZE) {
        proto_tree_add_text(tree, tvb, BGP_MIN_NOTIFICATION_MSG_SIZE,
          hlen - BGP_MIN_NOTIFICATION_MSG_SIZE, "Data");
    }
}

/*
 * Dissect a BGP ROUTE-REFRESH message.
 */
static void
dissect_bgp_route_refresh(tvbuff_t *tvb, proto_tree *tree)
{
    guint16         i;    /* tmp            */
    int             p;         /* tvb offset counter    */
    int               pend;   /* end of list of entries for one orf type */
    guint16     hlen;   /* tvb RR msg length */
    proto_item      *ti;       /* tree item             */
    proto_item      *ti1;       /* tree item             */
    proto_tree      *subtree;  /* tree for orf   */
    proto_tree      *subtree1; /* tree for orf entry */
    guint8          orftype;        /* ORF Type */
    guint8      orfwhen;          /* ORF flag: immediate, defer */
    guint16     orflen;     /* ORF len */
    guint8          entryflag;          /* ORF Entry flag: action(add,del,delall) match(permit,deny) */
    guint32     entryseq;       /* ORF Entry sequence number */
    int         entrylen;       /* ORF Entry length */
    guint8      pfx_ge;     /* ORF PrefixList mask lower bound */
    guint8          pfx_le;         /* ORF PrefixList mask upper bound */
    int             advance;        /* tmp                      */


/*
example 1
 00 1c 05   hlen=28
 00 01 00 01    afi,safi= ipv4-unicast
 02 80 00 01      defer, prefix-orf, len=1
    80            removeall
example 2
 00 25 05   hlen=37
 00 01 00 01      afi,saif= ipv4-unicast
 01 80 00 0a      immediate, prefix-orf, len=10
    00              add
    00 00 00 05   seqno = 5
    12              ge = 18
    18              le = 24
    10 07 02        prefix = 7.2.0.0/16
*/
    hlen = tvb_get_ntohs(tvb, BGP_MARKER_SIZE);
    p = BGP_HEADER_SIZE;
    /* AFI */
    i = tvb_get_ntohs(tvb, p);
    proto_tree_add_text(tree, tvb, p, 2,
                        "Address family identifier: %s (%u)",
                        val_to_str(i, afn_vals, "Unknown"), i);
    p += 2;
    /* Reserved */
    proto_tree_add_text(tree, tvb, p, 1,
                        "Reserved: 1 byte");
    p++;
    /* SAFI */
    i = tvb_get_guint8(tvb, p);
    proto_tree_add_text(tree, tvb, p, 1,
                        "Subsequent address family identifier: %s (%u)",
                        val_to_str(i, bgpattr_nlri_safi,
                        i >= 128 ? "Vendor specific" : "Unknown"),
                        i);
    p++;
    if ( hlen == BGP_HEADER_SIZE + 4 )
      return;
    while (p < hlen) {
      /* ORF type */
      orfwhen = tvb_get_guint8(tvb, p);
      orftype = tvb_get_guint8(tvb, p+1);
      orflen = tvb_get_ntohs(tvb, p+2);
      ti = proto_tree_add_text(tree, tvb, p , orflen + 4 , "ORF information (%u bytes)", orflen + 4);
      subtree = proto_item_add_subtree(ti, ett_bgp_orf);
      proto_tree_add_text(subtree, tvb, p , 1, "ORF flag: %s", val_to_str(orfwhen, orf_when_vals,"UNKNOWN"));
      proto_tree_add_text(subtree, tvb, p+1 , 1, "ORF type: %s", val_to_str(orftype, orf_type_vals,"UNKNOWN"));
      proto_tree_add_text(subtree, tvb, p+2 , 2, "ORF len: %u %s", orflen, (orflen == 1) ? "byte" : "bytes");
      p += 4;

      if (orftype != BGP_ORF_PREFIX_CISCO) {
            proto_tree_add_text(subtree, tvb, p, orflen,
                    "ORFEntry-Unknown (%u bytes)", orflen);
            p += orflen;
            continue;
        }
        pend = p + orflen;
        while (p < pend) {
            entryflag = tvb_get_guint8(tvb, p);
            if ((entryflag & BGP_ORF_ACTION) == BGP_ORF_REMOVEALL) {
                ti1 = proto_tree_add_text(subtree, tvb, p, 1,
                        "ORFEntry-PrefixList (1 byte)");
                subtree1 = proto_item_add_subtree(ti1, ett_bgp_orf_entry);
                proto_tree_add_text(subtree1, tvb, p , 1, "RemoveAll");
                p++;
            } else {
                ti1 = proto_tree_add_text(subtree, tvb, p, -1,
                        "ORFEntry-PrefixList");
                subtree1 = proto_item_add_subtree(ti1, ett_bgp_orf_entry);
                proto_tree_add_text(subtree1, tvb, p, 1,
                        "ACTION: %s MATCH: %s",
                        val_to_str(entryflag&BGP_ORF_ACTION,
                            orf_entry_action_vals, "UNKNOWN"),
                        val_to_str(entryflag&BGP_ORF_MATCH,
                            orf_entry_match_vals, "UNKNOWN"));
                p++;
                entryseq = tvb_get_ntohl(tvb, p);
                proto_tree_add_text(subtree1, tvb, p, 4,
                        "Entry Sequence No: %u", entryseq);
                p += 4;
                pfx_ge = tvb_get_guint8(tvb, p);
                proto_tree_add_text(subtree1, tvb, p, 1,
                        "PrefixMask length lower bound: %u", pfx_ge);
                p++;
                pfx_le = tvb_get_guint8(tvb, p);
                proto_tree_add_text(subtree1, tvb, p, 1,
                        "PrefixMask length upper bound: %u", pfx_le);
                p++;

                advance = decode_prefix4(subtree1, -1, tvb, p, 0, "ORF");
                if (advance < 0)
                        break;
                entrylen = 7 + 1 + advance;

                proto_item_append_text(ti1, " (%u bytes)", entrylen);
                proto_item_set_len(ti1, entrylen);
                p += advance;
            }
        }
    }
}

/*
 * Dissect a BGP CAPABILITY message.
 */
static void
dissect_bgp_capability(tvbuff_t *tvb, proto_tree *tree)
{
    int offset = 0;
    proto_item *ti;
    proto_tree *subtree;
    guint8  action;
    int ctype;
    int clen;
    int mend;

    mend = offset + tvb_get_ntohs(tvb, offset + BGP_MARKER_SIZE);
    offset += BGP_HEADER_SIZE;
    /* step through all of the capabilities */
    while (offset < mend) {
      action = tvb_get_guint8(tvb, offset++);
      ctype  = tvb_get_guint8(tvb, offset++);
      clen   = tvb_get_guint8(tvb, offset++);

      ti = proto_tree_add_text(tree, tvb, offset - 2, 2 + clen, 
             "%s (%u %s)", val_to_str(ctype, capability_vals,
             "Unknown capability"), 2 + clen, (clen == 1) ? "byte" : "bytes");
      subtree = proto_item_add_subtree(ti, ett_bgp_option);
      proto_tree_add_text(subtree, tvb, offset-2, 1, "Action: %d (%s)",
          action, val_to_str(action, bgpcap_action, "Invalid action value"));
      dissect_bgp_capability_item(tvb, &offset, subtree, ctype, clen);
    }
}

static void
dissect_bgp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
    gboolean first)
{
    guint16       bgp_len;       /* Message length             */
    guint8        bgp_type;      /* Message type               */
    char          *typ;          /* Message type (string)      */
    proto_item    *ti;           /* tree item                        */
    proto_tree    *bgp_tree;     /* BGP packet tree                  */
    proto_tree    *bgp1_tree;    /* BGP message tree                 */

    bgp_len = tvb_get_ntohs(tvb, BGP_MARKER_SIZE);
    bgp_type = tvb_get_guint8(tvb, BGP_MARKER_SIZE + 2);
    typ = val_to_str(bgp_type, bgptypevals, "Unknown message type (0x%02x)");

    if (check_col(pinfo->cinfo, COL_INFO)) {
      if (first)
          col_add_fstr(pinfo->cinfo, COL_INFO, "%s", typ);
      else
          col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", typ);
    }

    if (tree) {
      ti = proto_tree_add_item(tree, proto_bgp, tvb, 0, -1, FALSE);
      bgp_tree = proto_item_add_subtree(ti, ett_bgp);

      ti = proto_tree_add_text(bgp_tree, tvb, 0, -1, "%s", typ);

      /* add a different tree for each message type */
      switch (bgp_type) {
      case BGP_OPEN:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp_open);
          break;
      case BGP_UPDATE:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp_update);
          break;
      case BGP_NOTIFICATION:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp_notification);
          break;
      case BGP_KEEPALIVE:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp);
          break;
      case BGP_ROUTE_REFRESH_CISCO:
      case BGP_ROUTE_REFRESH:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp_route_refresh);
          break;
      case BGP_CAPABILITY:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp_capability);
          break;
      default:
          bgp1_tree = proto_item_add_subtree(ti, ett_bgp);
          break;
      }

      proto_tree_add_text(bgp1_tree, tvb, 0, BGP_MARKER_SIZE,
                      "Marker: 16 bytes");

      if (bgp_len < BGP_HEADER_SIZE || bgp_len > BGP_MAX_PACKET_SIZE) {
          proto_tree_add_text(bgp1_tree, tvb, BGP_MARKER_SIZE, 2,
                        "Length (invalid): %u %s", bgp_len,
                        (bgp_len == 1) ? "byte" : "bytes");
          return;
      } else {
          proto_tree_add_text(bgp1_tree, tvb, BGP_MARKER_SIZE, 2,
                        "Length: %u %s", bgp_len,
                        (bgp_len == 1) ? "byte" : "bytes");
      }

      proto_tree_add_uint(bgp1_tree, hf_bgp_type, tvb,
                           BGP_MARKER_SIZE + 2, 1,
                           bgp_type);

      switch (bgp_type) {
      case BGP_OPEN:
          dissect_bgp_open(tvb, bgp1_tree);
          break;
      case BGP_UPDATE:
          dissect_bgp_update(tvb, bgp1_tree);
          break;
      case BGP_NOTIFICATION:
          dissect_bgp_notification(tvb, bgp1_tree);
          break;
      case BGP_KEEPALIVE:
          /* no data in KEEPALIVE messages */
          break;
        case BGP_ROUTE_REFRESH_CISCO:
      case BGP_ROUTE_REFRESH:
          dissect_bgp_route_refresh(tvb, bgp1_tree);
          break;
      case BGP_CAPABILITY:
          dissect_bgp_capability(tvb, bgp1_tree);
          break;
      default:
          break;
      }
    }
}

/*
 * Dissect a BGP packet.
 */
static void
dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    volatile int  offset = 0;   /* offset into the tvbuff           */
    gint          reported_length_remaining;
    guint8        bgp_marker[BGP_MARKER_SIZE];    /* Marker (should be all ones */
    static guchar marker[] = {   /* BGP message marker               */
      0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
      0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    };
    proto_item    *ti;           /* tree item                        */
    proto_tree    *bgp_tree;     /* BGP packet tree                  */
    guint16       bgp_len;       /* Message length             */
    int           offset_before;
    guint         length_remaining;
    guint         length;
    volatile gboolean first = TRUE;  /* TRUE for the first BGP message in packet */
    tvbuff_t      *next_tvb;

    if (check_col(pinfo->cinfo, COL_PROTOCOL))
      col_set_str(pinfo->cinfo, COL_PROTOCOL, "BGP");
    if (check_col(pinfo->cinfo, COL_INFO))
      col_clear(pinfo->cinfo, COL_INFO);

    /*
     * Scan through the TCP payload looking for a BGP marker.
     */
    while ((reported_length_remaining = tvb_reported_length_remaining(tvb, offset))
            != 0) {
      /*
       * "reported_length_remaining" is the number of bytes of TCP payload
       * remaining.  If it's more than the length of a BGP marker,
       * we check only the number of bytes in a BGP marker.
       */
      if (reported_length_remaining > BGP_MARKER_SIZE)
          reported_length_remaining = BGP_MARKER_SIZE;

      /*
       * OK, is there a BGP marker starting at the specified offset -
       * or, at least, the beginning of a BGP marker running to the end
       * of the TCP payload?
       *
       * This will throw an exception if the frame is short; that's what
       * we want.
       */
      tvb_memcpy(tvb, bgp_marker, offset, reported_length_remaining);
      if (memcmp(bgp_marker, marker, reported_length_remaining) == 0) {
          /*
           * Yes - stop scanning and start processing BGP packets.
           */
          break;
      }

      /*
       * No - keep scanning through the tvbuff to try to find a marker.
       */
      offset++;
    }

    /*
     * If we skipped any bytes, mark it as a BGP continuation.
     */
    if (offset > 0) {
      ti = proto_tree_add_item(tree, proto_bgp, tvb, 0, -1, FALSE);
      bgp_tree = proto_item_add_subtree(ti, ett_bgp);

      proto_tree_add_text(bgp_tree, tvb, 0, offset, "Continuation");
    }

    /*
     * Now process the BGP packets in the TCP payload.
     *
     * XXX - perhaps "tcp_dissect_pdus()" should take a starting
     * offset, in which case we can replace the loop below with
     * a call to "tcp_dissect_pdus()".
     */
    while (tvb_reported_length_remaining(tvb, offset) != 0) {
      /*
       * This will throw an exception if we don't have any data left.
       * That's what we want.  (See "tcp_dissect_pdus()", which is
       * similar.)
       */
      length_remaining = tvb_ensure_length_remaining(tvb, offset);

      /*
       * Can we do reassembly?
       */
      if (bgp_desegment && pinfo->can_desegment) {
          /*
           * Yes - would a BGP header starting at this offset be split
           * across segment boundaries?
           */
          if (length_remaining < BGP_HEADER_SIZE) {
            /*
             * Yes.  Tell the TCP dissector where the data for this
             * message starts in the data it handed us, and how many
             * more bytes we need, and return.
             */
            pinfo->desegment_offset = offset;
            pinfo->desegment_len = BGP_HEADER_SIZE - length_remaining;
            return;
          }
      }

      /*
       * Get the length and type from the BGP header.
       */
      bgp_len = tvb_get_ntohs(tvb, offset + BGP_MARKER_SIZE);
      if (bgp_len < BGP_HEADER_SIZE) {
          /*
           * The BGP length doesn't include the BGP header; report that
           * as an error.
           */
          show_reported_bounds_error(tvb, pinfo, tree);
          return;
      }

      /*
       * Can we do reassembly?
       */
      if (bgp_desegment && pinfo->can_desegment) {
          /*
           * Yes - is the PDU split across segment boundaries?
           */
          if (length_remaining < bgp_len) {
            /*
             * Yes.  Tell the TCP dissector where the data for this
             * message starts in the data it handed us, and how many
             * more bytes we need, and return.
             */
            pinfo->desegment_offset = offset;
            pinfo->desegment_len = bgp_len - length_remaining;
            return;
          }
      }

      /*
       * Construct a tvbuff containing the amount of the payload we have
       * available.  Make its reported length the amount of data in the PDU.
       *
       * XXX - if reassembly isn't enabled. the subdissector will throw a
       * BoundsError exception, rather than a ReportedBoundsError exception.
       * We really want a tvbuff where the length is "length", the reported
       * length is "plen", and the "if the snapshot length were infinite"
       * length is the minimum of the reported length of the tvbuff handed
       * to us and "plen", with a new type of exception thrown if the offset
       * is within the reported length but beyond that third length, with
       * that exception getting the "Unreassembled Packet" error.
       */
      length = length_remaining;
      if (length > bgp_len)
          length = bgp_len;
      next_tvb = tvb_new_subset(tvb, offset, length, bgp_len);

      /*
       * Dissect the PDU.
       *
       * Catch the ReportedBoundsError exception; if this particular message
       * happens to get a ReportedBoundsError exception, that doesn't mean
       * that we should stop dissecting PDUs within this frame or chunk of
       * reassembled data.
       *
       * If it gets a BoundsError, we can stop, as there's nothing more to
       * see, so we just re-throw it.
       */
      TRY {
          dissect_bgp_pdu(next_tvb, pinfo, tree, first);
      }
      CATCH(BoundsError) {
          RETHROW;
      }
      CATCH(ReportedBoundsError) {
          show_reported_bounds_error(tvb, pinfo, tree);
      }
      ENDTRY;

      first = FALSE;

      /*
       * Step to the next PDU.
       * Make sure we don't overflow.
       */
      offset_before = offset;
      offset += bgp_len;
      if (offset <= offset_before)
          break;
    }
}

/*
 * Register ourselves.
 */
void
proto_register_bgp(void)
{

    static hf_register_info hf[] = {
      { &hf_bgp_type,
      { "Type", "bgp.type", FT_UINT8, BASE_DEC,
        VALS(bgptypevals), 0x0, "BGP message type", HFILL }},
      { &hf_bgp_aggregator_as,
      { "Aggregator AS", "bgp.aggregator_as", FT_UINT16, BASE_DEC,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_aggregator_origin,
      { "Aggregator origin", "bgp.aggregator_origin", FT_IPv4, BASE_NONE,
        NULL, 0x0, "", HFILL}}, 
      { &hf_bgp_as_path,
      { "AS Path", "bgp.as_path", FT_UINT16, BASE_DEC,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_cluster_identifier,
      { "Cluster identifier", "bgp.cluster_identifier", FT_IPv4, BASE_NONE,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_community_as,
      { "Community AS", "bgp.community_as", FT_UINT16, BASE_DEC,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_community_value,
      { "Community value", "bgp.community_value", FT_UINT16, BASE_DEC,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_local_pref,
      { "Local preference", "bgp.local_pref", FT_UINT32, BASE_DEC,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_mp_reach_nlri_ipv4_prefix,
      { "MP Reach NLRI IPv4 prefix", "bgp.mp_reach_nlri_ipv4_prefix", FT_IPv4, BASE_NONE,
          NULL, 0x0, "", HFILL}},
      { &hf_bgp_mp_unreach_nlri_ipv4_prefix,
      { "MP Unreach NLRI IPv4 prefix", "bgp.mp_unreach_nlri_ipv4_prefix", FT_IPv4, BASE_NONE,
          NULL, 0x0, "", HFILL}}, 
      { &hf_bgp_mp_nlri_tnl_id,
        { "MP Reach NLRI Tunnel Identifier", "bgp.mp_nlri_tnl_id", FT_UINT16, BASE_HEX,
          NULL, 0x0, "", HFILL}},
      { &hf_bgp_multi_exit_disc,
      { "Multiple exit discriminator", "bgp.multi_exit_disc", FT_UINT32, BASE_DEC,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_next_hop,
      { "Next hop", "bgp.next_hop", FT_IPv4, BASE_NONE,
          NULL, 0x0, "", HFILL}}, 
      { &hf_bgp_nlri_prefix,
        { "NLRI prefix", "bgp.nlri_prefix", FT_IPv4, BASE_NONE,
          NULL, 0x0, "", HFILL}}, 
      { &hf_bgp_origin,
      { "Origin", "bgp.origin", FT_UINT8, BASE_DEC,
        VALS(bgpattr_origin), 0x0, "", HFILL}},
      { &hf_bgp_originator_id,
      { "Originator identifier", "bgp.originator_id", FT_IPv4, BASE_NONE,
        NULL, 0x0, "", HFILL}},
      { &hf_bgp_ssa_t,
        { "Transitive bit", "bgp.ssa_t", FT_BOOLEAN, 8,
          NULL, 0x80, "SSA Transitive bit", HFILL}},
      { &hf_bgp_ssa_type,
        { "SSA Type", "bgp.ssa_type", FT_UINT16, BASE_DEC,
          VALS(bgp_ssa_type), 0x7FFF, "SSA Type", HFILL}},
      { &hf_bgp_ssa_len,
        { "Length", "bgp.ssa_len", FT_UINT16, BASE_DEC,
          NULL, 0x0, "SSA Length", HFILL}},
      { &hf_bgp_ssa_value,
        { "Value", "bgp.ssa_value", FT_BYTES, BASE_HEX,
          NULL, 0x0, "SSA Value", HFILL}},
      { &hf_bgp_ssa_l2tpv3_pref,
        { "Preference", "bgp.ssa_l2tpv3_pref", FT_UINT16, BASE_DEC,
          NULL, 0x0, "Preference", HFILL}},
      { &hf_bgp_ssa_l2tpv3_s,
        { "Sequencing bit", "bgp.ssa_l2tpv3_s", FT_BOOLEAN, 8,
          NULL, 0x80, "Sequencing S-bit", HFILL}},
      { &hf_bgp_ssa_l2tpv3_unused,
        { "Unused", "bgp.ssa_l2tpv3_Unused", FT_BOOLEAN, 8,
          NULL, 0x7F, "Unused Flags", HFILL}},
      { &hf_bgp_ssa_l2tpv3_cookie_len,
        { "Cookie Length", "bgp.ssa_l2tpv3_cookie_len", FT_UINT8, BASE_DEC,
          NULL, 0x0, "Cookie Length", HFILL}},
      { &hf_bgp_ssa_l2tpv3_session_id,
        { "Session ID", "bgp.ssa_l2tpv3_session_id", FT_UINT32, BASE_DEC,
          NULL, 0x0, "Session ID", HFILL}},
      { &hf_bgp_ssa_l2tpv3_cookie,
        { "Cookie", "bgp.ssa_l2tpv3_cookie", FT_BYTES, BASE_HEX,
          NULL, 0x0, "Cookie", HFILL}},
      { &hf_bgp_withdrawn_prefix,
        { "Withdrawn prefix", "bgp.withdrawn_prefix", FT_IPv4, BASE_NONE,
          NULL, 0x0, "", HFILL}}, 
      { &hf_bgp_cluster_list,
        { "Cluster List", "bgp.cluster_list", FT_BYTES, BASE_HEX,
          NULL, 0x0, "", HFILL}}, 
    };

    static gint *ett[] = {
      &ett_bgp,
      &ett_bgp_prefix,
      &ett_bgp_unfeas,
      &ett_bgp_attrs,
      &ett_bgp_attr,
      &ett_bgp_attr_flags,
      &ett_bgp_mp_nhna,
      &ett_bgp_mp_reach_nlri,
      &ett_bgp_mp_unreach_nlri,
      &ett_bgp_mp_snpa,
      &ett_bgp_nlri,
      &ett_bgp_open,
      &ett_bgp_update,
      &ett_bgp_notification,
      &ett_bgp_route_refresh,
      &ett_bgp_capability,
      &ett_bgp_as_paths,
      &ett_bgp_as_path_segments,
      &ett_bgp_communities,
      &ett_bgp_cluster_list,
      &ett_bgp_options,
      &ett_bgp_option,
      &ett_bgp_extended_communities,
      &ett_bgp_ssa,
      &ett_bgp_ssa_subtree,
      &ett_bgp_orf,
      &ett_bgp_orf_entry
    };
    module_t *bgp_module;
    static enum_val_t asn_len[] = {
      {"auto-detect", "Auto-detect", 0},
      {"2", "2 octet", 2},
      {"4", "4 octet", 4},
      {NULL, NULL, -1}
    };

    proto_bgp = proto_register_protocol("Border Gateway Protocol",
                              "BGP", "bgp");
    proto_register_field_array(proto_bgp, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));

    bgp_module = prefs_register_protocol(proto_bgp, NULL);
    prefs_register_bool_preference(bgp_module, "desegment",
      "Reassemble BGP messages spanning multiple TCP segments",
      "Whether the BGP dissector should reassemble messages spanning multiple TCP segments."
      " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
      &bgp_desegment);
    prefs_register_enum_preference(bgp_module, "asn_len",
      "Length of the AS number",
      "BGP dissector detect the length of the AS number in AS_PATH attributes automatically or manually (NOTE: Automatic detection is not 100% accurate)",
      &bgp_asn_len, asn_len, FALSE);
}

void
proto_reg_handoff_bgp(void)
{
    dissector_handle_t bgp_handle;

    bgp_handle = create_dissector_handle(dissect_bgp, proto_bgp);
    dissector_add("tcp.port", BGP_TCP_PORT, bgp_handle);
}

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