/* packet-dhpcv6.c
 * Routines for DHCPv6 packet disassembly
 * Copyright 2004, Nicolas DICHTEL - 6WIND - <nicolas.dichtel@6wind.com>
 * Jun-ichiro itojun Hagino <itojun@iijlab.net>
 * IItom Tsutomu MIENO <iitom@utouto.com>
 * SHIRASAKI Yasuhiro <yasuhiro@gnome.gr.jp>
 * Tony Lindstrom <tony.lindstrom@ericsson.com>
 *
 * $Id: packet-dhcpv6.c 14969 2005-07-20 12:20:56Z sahlberg $
 *
 * The information used comes from:
 * RFC3315.txt (DHCPv6)
 * RFC3319.txt (SIP options)
 * RFC3633.txt (Prefix options)
 * RFC3646.txt (DNS servers/domains)
 * RFC3898.txt (NIS options)
 * draft-ietf-dhc-dhcpv6-opt-timeconfig-03.txt
 * draft-ietf-dhc-dhcpv6-opt-fqdn-00.txt
 * draft-ietf-dhc-dhcpv6-opt-lifetime-00.txt
 *
 * Note that protocol constants are still subject to change, based on IANA
 * assignment decisions.
 *
 * 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 <string.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/ipv6-utils.h>
#include "packet-arp.h"

static int proto_dhcpv6 = -1;
static int hf_dhcpv6_msgtype = -1;
static int hf_fqdn_1 = -1;
static int hf_fqdn_2 = -1;
static int hf_fqdn_3 = -1;
static int hf_fqdn_4 = -1;

static gint ett_dhcpv6 = -1;
static gint ett_dhcpv6_option = -1;

#define UDP_PORT_DHCPV6_DOWNSTREAM	546
#define UDP_PORT_DHCPV6_UPSTREAM	547

#define DHCPV6_LEASEDURATION_INFINITY	0xffffffff

#define	SOLICIT			1
#define	ADVERTISE		2
#define	REQUEST			3
#define	CONFIRM			4
#define	RENEW			5
#define	REBIND			6
#define	REPLY			7
#define	RELEASE			8
#define	DECLINE			9
#define	RECONFIGURE		10
#define	INFORMATION_REQUEST	11
#define	RELAY_FORW		12
#define	RELAY_REPLY		13

#define	OPTION_CLIENTID		1
#define	OPTION_SERVERID		2
#define	OPTION_IA_NA		3
#define	OPTION_IA_TA		4
#define	OPTION_IAADDR		5
#define	OPTION_ORO		6
#define	OPTION_PREFERENCE	7
#define	OPTION_ELAPSED_TIME	8
#define	OPTION_RELAY_MSG	9
/* #define	OPTION_SERVER_MSG	10 */
#define	OPTION_AUTH		11
#define	OPTION_UNICAST		12
#define	OPTION_STATUS_CODE	13
#define	OPTION_RAPID_COMMIT	14
#define	OPTION_USER_CLASS	15
#define	OPTION_VENDOR_CLASS	16
#define	OPTION_VENDOR_OPTS	17
#define	OPTION_INTERFACE_ID	18
#define	OPTION_RECONF_MSG	19
#define	OPTION_RECONF_ACCEPT	20
#define	OPTION_SIP_SERVER_D	21
#define	OPTION_SIP_SERVER_A	22
#define	OPTION_DNS_SERVERS	23
#define	OPTION_DOMAIN_LIST      24
#define	OPTION_IA_PD		25
#define	OPTION_IAPREFIX		26
#define OPTION_NIS_SERVERS	27
#define OPTION_NISP_SERVERS	28
#define OPTION_NIS_DOMAIN_NAME  29
#define OPTION_NISP_DOMAIN_NAME 30

/*
 * The followings are unassigned numbers.
 */
#define OPTION_CLIENT_FQDN      34
#define OPTION_SNTP_SERVERS	40
#define OPTION_TIME_ZONE	41
#define OPTION_LIFETIME         42

/* temporary value until defined by IETF */
#define OPTION_MIP6_HA		165
#define OPTION_MIP6_HOA		166
#define OPTION_NAI		167

#define	DUID_LLT		1
#define	DUID_EN			2
#define	DUID_LL			3
#define	DUID_LL_OLD		4

static void
dissect_dhcpv6(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
    gboolean downstream, int off, int eoff);

static const value_string msgtype_vals[] = {
	{ SOLICIT,	"Solicit" },
	{ ADVERTISE,	"Advertise" },
	{ REQUEST,	"Request" },
	{ CONFIRM,	"Confirm" },
	{ RENEW,	"Renew" },
	{ REBIND,	"Rebind" },
	{ REPLY,	"Reply" },
	{ RELEASE,	"Release" },
	{ DECLINE,	"Decline" },
	{ RECONFIGURE,	"Reconfigure" },
	{ INFORMATION_REQUEST,	"Information-request" },
	{ RELAY_FORW,	"Relay-forw" },
	{ RELAY_REPLY,	"Relay-reply" },
	{ 0, NULL }
};

static const value_string opttype_vals[] = {
	{ OPTION_CLIENTID,	"Client Identifier" },
	{ OPTION_SERVERID,	"Server Identifier" },
	{ OPTION_IA_NA,		"Identity Association for Non-temporary Address" },
	{ OPTION_IA_TA,		"Identity Association for Temporary Address" },
	{ OPTION_IAADDR,	"IA Address" },
	{ OPTION_ORO,		"Option Request" },
	{ OPTION_PREFERENCE,	"Preference" },
	{ OPTION_ELAPSED_TIME,	"Elapsed time" },
	{ OPTION_RELAY_MSG,	"Relay Message" },
/*	{ OPTION_SERVER_MSG,	"Server message" }, */
	{ OPTION_AUTH,		"Authentication" },
	{ OPTION_UNICAST,	"Server unicast" },
	{ OPTION_STATUS_CODE,	"Status code" },
	{ OPTION_RAPID_COMMIT,	"Rapid Commit" },
	{ OPTION_USER_CLASS,	"User Class" },
	{ OPTION_VENDOR_CLASS,	"Vendor Class" },
	{ OPTION_VENDOR_OPTS,	"Vendor-specific Information" },
	{ OPTION_INTERFACE_ID,	"Interface-Id" },
	{ OPTION_RECONF_MSG,	"Reconfigure Message" },
	{ OPTION_RECONF_ACCEPT,	"Reconfigure Accept" },
	{ OPTION_SIP_SERVER_D,	"SIP Server Domain Name List" },
	{ OPTION_SIP_SERVER_A,	"SIP Servers IPv6 Address List" },
	{ OPTION_DNS_SERVERS,	"DNS recursive name server" },
	{ OPTION_DOMAIN_LIST,	"Domain Search List" },
	{ OPTION_IA_PD,		"Identity Association for Prefix Delegation" },
	{ OPTION_IAPREFIX,	"IA Prefix" },
	{ OPTION_NIS_SERVERS,	"Network Information Server" },
	{ OPTION_NISP_SERVERS,	"Network Information Server V2" },
	{ OPTION_NIS_DOMAIN_NAME, "Network Information Server Domain Name" },
	{ OPTION_NISP_DOMAIN_NAME,"Network Information Server V2 Domain Name" },
	{ OPTION_SNTP_SERVERS,	"Simple Network Time Protocol Server" },
	{ OPTION_TIME_ZONE,	"Time zone" },
	{ OPTION_LIFETIME,      "Lifetime" },
	{ OPTION_CLIENT_FQDN,   "Fully Qualified Domain Name" },
	{ OPTION_MIP6_HA,	"Mobile IPv6 Home Agent" },
	{ OPTION_MIP6_HOA,	"Mobile IPv6 Home Address" },
	{ OPTION_NAI,		"Network Access Identifier" },
	{ 0,	NULL }
};

static const value_string statuscode_vals[] =
{
	{0, "Success" },
	{1, "UnspecFail" },
	{2, "NoAddrAvail" },
	{3, "NoBinding" },
	{4, "NotOnLink" },
	{5, "UseMulticast" },
	{6, "NoPrefixAvail" },
	{0, NULL }
};

static const value_string duidtype_vals[] =
{
	{ DUID_LLT,	"link-layer address plus time" },
	{ DUID_EN,	"assigned by vendor based on Enterprise number" },
	{ DUID_LL,	"link-layer address" },
	{ DUID_LL_OLD,	"link-layer address (old)" },
	{ 0, NULL }
};

/* This FQDN draft is a mess, I've tried to understand, 
   but N,O,S bit descriptions are really cryptic */
static const true_false_string fqdn_n = {
/*    "Client doesn't want server to perform DNS update", "" */
    "N bit set","N bit cleared"
};

static const true_false_string fqdn_o = {
    "O bit set", "O bit cleared" 
};

static const true_false_string fqdn_s = {
/*    "Forward mapping (FQDN-to-IPv6, AAAA) performed by client", 
      "Forward mapping (FQDN-to-IPv6, AAAA) performed by server" */
    "S bit set", "S bit cleared"
}; 

/* Adds domain */
static void
dhcpv6_domain(proto_tree * subtree, tvbuff_t *tvb, int offset, guint16 optlen)
{
    int start_offset=offset;
    char domain[256];
    int pos;
    guint8 len;

    pos=0;
    while(optlen){
        /* this is the start of the domain name */
        if(!pos){
            start_offset=offset;
        }
        domain[pos]=0;

        /* read length of the next substring */
        len = tvb_get_guint8(tvb, offset);
        offset++;
        optlen--;

        /* if len==0 and pos>0 we have read an entire domain string */
        if(!len){
            if(!pos){
                /* empty string, this must be an error? */
                proto_tree_add_text(subtree, tvb, start_offset, offset-start_offset, "Malformed option");
                return;
            } else {
                proto_tree_add_text(subtree, tvb, start_offset, offset-start_offset, "Domain: %s", domain);
                pos=0;
                continue;
            }
        }

        /* add the substring to domain */
        if(pos){
            domain[pos]='.';
            pos++;
        }
        if(pos+len>254){
                /* too long string, this must be an error? */
                proto_tree_add_text(subtree, tvb, start_offset, offset-start_offset, "Malformed option");
                return;
        }
        tvb_memcpy(tvb, domain+pos, offset, len);
        pos+=len;
        offset+=len;
        optlen-=len;
    }        
    
    if(pos){
        domain[pos]=0;
        proto_tree_add_text(subtree, tvb, start_offset, offset-start_offset, "Domain: %s", domain);
    }
}    

/* Returns the number of bytes consumed by this option. */
static int
dhcpv6_option(tvbuff_t *tvb, packet_info *pinfo, proto_tree *bp_tree, 
		gboolean downstream, int off, int eoff, gboolean *at_end)
{
	guint8 *buf;
	guint16	opttype;
	guint16	optlen;
	guint16	hwtype;
	guint16	temp_optlen = 0;
	proto_item *ti;
	proto_tree *subtree;
	int i;
	struct e_in6_addr in6;
	guint16 duidtype;

	/* option type and length must be present */
	if (eoff - off < 4) {
		*at_end = TRUE;
		return 0;
	}

	opttype = tvb_get_ntohs(tvb, off);
	optlen = tvb_get_ntohs(tvb, off + 2);

	/* all option data must be present */
	if (eoff - off < 4 + optlen) {
		*at_end = TRUE;
		return 0;
	}

	ti = proto_tree_add_text(bp_tree, tvb, off, 4 + optlen,
		"%s", val_to_str(opttype, opttype_vals, "DHCP option %u"));

	subtree = proto_item_add_subtree(ti, ett_dhcpv6_option);
	proto_tree_add_text(subtree, tvb, off, 2, "option type: %d", opttype);
	proto_tree_add_text(subtree, tvb, off + 2, 2, "option length: %d",
		optlen);

	off += 4;
	switch (opttype) {
	case OPTION_CLIENTID:
	case OPTION_SERVERID:
		if (optlen < 2) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"DUID: malformed option");
			break;
		}
		duidtype = tvb_get_ntohs(tvb, off);
		proto_tree_add_text(subtree, tvb, off, 2,
			"DUID type: %s (%u)",
				    val_to_str(duidtype,
					       duidtype_vals, "Unknown"),
				    duidtype);
		switch (duidtype) {
		case DUID_LLT:
			if (optlen < 8) {
				proto_tree_add_text(subtree, tvb, off,
					optlen, "DUID: malformed option");
				break;
			}
			hwtype=tvb_get_ntohs(tvb, off + 2);
			proto_tree_add_text(subtree, tvb, off + 2, 2,
				"Hardware type: %s (%u)",
				arphrdtype_to_str(hwtype, "Unknown"),
				hwtype);
			/* XXX seconds since Jan 1 2000 */
			proto_tree_add_text(subtree, tvb, off + 4, 4,
				"Time: %u", tvb_get_ntohl(tvb, off + 4));
			if (optlen > 8) {
				proto_tree_add_text(subtree, tvb, off + 8,
					optlen - 8, "Link-layer address: %s",
					arphrdaddr_to_str(tvb_get_ptr(tvb, off+8, optlen-8), optlen-8, hwtype));
			}
			break;
		case DUID_EN:
			if (optlen < 6) {
				proto_tree_add_text(subtree, tvb, off,
					optlen, "DUID: malformed option");
				break;
			}
			proto_tree_add_text(subtree, tvb, off + 2, 4,
					    "enterprise-number");
			if (optlen > 6) {
				proto_tree_add_text(subtree, tvb, off + 6,
					optlen - 6, "identifier");
			}
			break;
		case DUID_LL:
		case DUID_LL_OLD:
			if (optlen < 4) {
				proto_tree_add_text(subtree, tvb, off,
					optlen, "DUID: malformed option");
				break;
			}
			hwtype=tvb_get_ntohs(tvb, off + 2);
			proto_tree_add_text(subtree, tvb, off + 2, 2,
				"Hardware type: %s (%u)",
				arphrdtype_to_str(hwtype, "Unknown"),
				hwtype);
			if (optlen > 4) {
				proto_tree_add_text(subtree, tvb, off + 4,
					optlen - 4, "Link-layer address: %s",
					arphrdaddr_to_str(tvb_get_ptr(tvb, off+4, optlen-4), optlen-4, hwtype));
			}
			break;
		}
		break;
	case OPTION_IA_NA:
	case OPTION_IA_PD:
          if (optlen < 12) {
             if (opttype == OPTION_IA_NA)
                proto_tree_add_text(subtree, tvb, off,
                                    optlen, "IA_NA: malformed option");
             else
                proto_tree_add_text(subtree, tvb, off,
                                    optlen, "IA_PD: malformed option");
             break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 4,
			      "IAID: %u",
			      tvb_get_ntohl(tvb, off));
	  if (tvb_get_ntohl(tvb, off+4) == DHCPV6_LEASEDURATION_INFINITY) {
	      proto_tree_add_text(subtree, tvb, off+4, 4,
				  "T1: infinity");
	  } else {
	      proto_tree_add_text(subtree, tvb, off+4, 4,
				  "T1: %u", tvb_get_ntohl(tvb, off+4));
	  }

	  if (tvb_get_ntohl(tvb, off+8) == DHCPV6_LEASEDURATION_INFINITY) {
	      proto_tree_add_text(subtree, tvb, off+8, 4,
				  "T2: infinity");
	  } else {
	      proto_tree_add_text(subtree, tvb, off+8, 4,
				  "T2: %u", tvb_get_ntohl(tvb, off+8));
	  }

          temp_optlen = 12;
	  while ((optlen - temp_optlen) > 0) {
	    temp_optlen += dhcpv6_option(tvb, pinfo, subtree, downstream,
			    off+temp_optlen, off + optlen, at_end);
	    if (*at_end) {
	      /* Bad option - just skip to the end */
	      temp_optlen = optlen;
	    }
	  }
	  break;
	case OPTION_IA_TA:
	  if (optlen < 4) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "IA_TA: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 4,
			      "IAID: %u",
			      tvb_get_ntohl(tvb, off));
          temp_optlen = 4;
	  while ((optlen - temp_optlen) > 0) {
	    temp_optlen += dhcpv6_option(tvb, pinfo, subtree, downstream,
			    off+temp_optlen, off + optlen, at_end);
	    if (*at_end) {
	      /* Bad option - just skip to the end */
	      temp_optlen = optlen;
	    }
	  }
	  break;
	case OPTION_IAADDR:
        {
           guint32 preferred_lifetime, valid_lifetime;

           if (optlen < 24) {
              proto_tree_add_text(subtree, tvb, off,
                                  optlen, "IAADDR: malformed option");
              break;
           }
           tvb_memcpy(tvb, (guint8 *)&in6, off, sizeof(in6));
           proto_tree_add_text(subtree, tvb, off,
                               sizeof(in6), "IPv6 address: %s",
                               ip6_to_str(&in6));
           
           preferred_lifetime = tvb_get_ntohl(tvb, off + 16);
           valid_lifetime = tvb_get_ntohl(tvb, off + 20);
           
           if (preferred_lifetime == DHCPV6_LEASEDURATION_INFINITY) {
              proto_tree_add_text(subtree, tvb, off + 16, 4,
                                  "Preferred lifetime: infinity");
           } else {
              proto_tree_add_text(subtree, tvb, off + 16, 4,
                                  "Preferred lifetime: %u", preferred_lifetime);
           }
           if (valid_lifetime == DHCPV6_LEASEDURATION_INFINITY) {
              proto_tree_add_text(subtree, tvb, off + 20, 4,
                                  "Valid lifetime: infinity");
           } else {
              proto_tree_add_text(subtree, tvb, off + 20, 4,
                                  "Valid lifetime: %u", valid_lifetime);
           }
           
           temp_optlen = 24;
           while ((optlen - temp_optlen) > 0) {
              temp_optlen += dhcpv6_option(tvb, pinfo, subtree, downstream,
			      off+temp_optlen, off + optlen, at_end);
              if (*at_end) {
                /* Bad option - just skip to the end */
                temp_optlen = optlen;
              }
           }
        }
        break;
	case OPTION_ORO:
		for (i = 0; i < optlen; i += 2) {
		    guint16 requested_opt_code;
		    requested_opt_code = tvb_get_ntohs(tvb, off + i);
		    proto_tree_add_text(subtree, tvb, off + i,
			    2, "Requested Option code: %s (%d)",
					    val_to_str(requested_opt_code,
						       opttype_vals,
						       "Unknown"),
					    requested_opt_code);
		}
		break;
	case OPTION_PREFERENCE:
	  if (optlen != 1) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "PREFERENCE: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 1,
			      "pref-value: %d",
			      (guint32)tvb_get_guint8(tvb, off));
	  break;
	case OPTION_ELAPSED_TIME:
	  if (optlen != 2) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "ELAPSED-TIME: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 2,
			      "elapsed-time: %d sec",
			      (guint32)tvb_get_ntohs(tvb, off));
	  break;
	case OPTION_RELAY_MSG:
	  if (optlen == 0) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "RELAY-MSG: malformed option");
	  } else {
	    /* here, we should dissect a full DHCP message */
	    dissect_dhcpv6(tvb, pinfo, subtree, downstream, off, off + optlen);
          } 
	  break;
	case OPTION_AUTH:
	  if (optlen < 11) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "AUTH: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 1,
			      "Protocol: %d",
			      (guint32)tvb_get_guint8(tvb, off));
	  proto_tree_add_text(subtree, tvb, off+1, 1,
			      "Algorithm: %d",
			      (guint32)tvb_get_guint8(tvb, off+1));
	  proto_tree_add_text(subtree, tvb, off+2, 1,
			      "RDM: %d",
			      (guint32)tvb_get_guint8(tvb, off+2));
	  proto_tree_add_text(subtree, tvb, off+3, 8,
			      "Replay Detection");
	  if (optlen != 11)
		proto_tree_add_text(subtree, tvb, off+11, optlen-11,
							"Authentication Information");
	  break;
	case OPTION_UNICAST:
	  if (optlen != 16) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "UNICAST: malformed option");
	    break;
	  }
	  tvb_memcpy(tvb, (guint8 *)&in6, off, sizeof(in6));
	  proto_tree_add_text(subtree, tvb, off,
			      sizeof(in6), "IPv6 address: %s",
				ip6_to_str(&in6));
	  break;
	case OPTION_STATUS_CODE:
	    {
		guint16 status_code;
		char *status_message = 0;
		status_code = tvb_get_ntohs(tvb, off);
		proto_tree_add_text(subtree, tvb, off, 2,
				    "Status Code: %s (%d)",
				    val_to_str(status_code, statuscode_vals,
					       "Unknown"),
				    status_code);

		if (optlen - 2 > 0) {
		    status_message = tvb_get_string(tvb, off + 2, optlen - 2);
		    proto_tree_add_text(subtree, tvb, off + 2, optlen - 2,
					"Status Message: %s",
					status_message);
		    g_free(status_message);
		}
	    }
	    break;
	case OPTION_VENDOR_CLASS:
	  if (optlen < 4) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "VENDOR_CLASS: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 4,
			      "enterprise-number: %u",
			      tvb_get_ntohl(tvb, off));
	  if (optlen > 4) {
	    proto_tree_add_text(subtree, tvb, off+4, optlen-4,
				"vendor-class-data");
	  }
	  break;
	case OPTION_VENDOR_OPTS:
	  if (optlen < 4) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "VENDOR_OPTS: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 4,
			      "enterprise-number: %u",
			      tvb_get_ntohl(tvb, off));
	  if (optlen > 4) {
	    proto_tree_add_text(subtree, tvb, off+4, optlen-4,
				"option-data");
	  }
	  break;
	case OPTION_INTERFACE_ID:
	  if (optlen == 0) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "INTERFACE_ID: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, optlen, "Interface-ID");
	  break;
	case OPTION_RECONF_MSG:
	  if (optlen != 1) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "RECONF_MSG: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, optlen,
			      "Reconfigure-type: %s",
			      val_to_str(tvb_get_guint8(tvb, off),
					 msgtype_vals,
					 "Message Type %u"));
	  break;
	case OPTION_SIP_SERVER_D:
		if (optlen > 0) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"SIP Servers Domain Search List");
		}
		dhcpv6_domain(subtree,tvb, off, optlen);
		break;
	case OPTION_SIP_SERVER_A:
		if (optlen % 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"SIP servers address: malformed option");
			break;
		}
		for (i = 0; i < optlen; i += 16) {
			tvb_memcpy(tvb, (guint8 *)&in6, off + i, sizeof(in6));
			proto_tree_add_text(subtree, tvb, off + i,
				sizeof(in6), "SIP servers address: %s",
				ip6_to_str(&in6));
		}
		break;
	case OPTION_DNS_SERVERS:
		if (optlen % 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"DNS servers address: malformed option");
			break;
		}
		for (i = 0; i < optlen; i += 16) {
			tvb_memcpy(tvb, (guint8 *)&in6, off + i, sizeof(in6));
			proto_tree_add_text(subtree, tvb, off + i,
				sizeof(in6), "DNS servers address: %s",
				ip6_to_str(&in6));
		}
		break;
	case OPTION_DOMAIN_LIST:
	  if (optlen > 0) {
	    proto_tree_add_text(subtree, tvb, off, optlen, "DNS Domain Search List");
	  }
	  dhcpv6_domain(subtree,tvb, off, optlen);
	  break;
	case OPTION_NIS_SERVERS:
		if (optlen % 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"NIS servers address: malformed option");
			break;
		}
		for (i = 0; i < optlen; i += 16) {
			tvb_memcpy(tvb, (guint8 *)&in6, off + i, sizeof(in6));
			proto_tree_add_text(subtree, tvb, off + i,
				sizeof(in6), "NIS servers address: %s",
				ip6_to_str(&in6));
		}
		break;
	case OPTION_NISP_SERVERS:
		if (optlen % 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"NISP servers address: malformed option");
			break;
		}
		for (i = 0; i < optlen; i += 16) {
			tvb_memcpy(tvb, (guint8 *)&in6, off + i, sizeof(in6));
			proto_tree_add_text(subtree, tvb, off + i,
				sizeof(in6), "NISP servers address: %s",
				ip6_to_str(&in6));
		}
		break;
	case OPTION_NIS_DOMAIN_NAME:
	  if (optlen > 0) {
	    proto_tree_add_text(subtree, tvb, off, optlen, "nis-domain-name");
	  }
	  dhcpv6_domain(subtree,tvb, off, optlen);
	  break;
	case OPTION_NISP_DOMAIN_NAME:
	  if (optlen > 0) {
	    proto_tree_add_text(subtree, tvb, off, optlen, "nisp-domain-name");
	  }
	  dhcpv6_domain(subtree,tvb, off, optlen);
	  break;
	case OPTION_SNTP_SERVERS:
		if (optlen % 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"SNTP servers address: malformed option");
			break;
		}
		for (i = 0; i < optlen; i += 16) {
			tvb_memcpy(tvb, (guint8 *)&in6, off + i, sizeof(in6));
			proto_tree_add_text(subtree, tvb, off + i,
				sizeof(in6), "SNTP servers address: %s",
				ip6_to_str(&in6));
		}
		break;
	case OPTION_TIME_ZONE:
	  if (optlen > 0) {
	      buf = tvb_get_string(tvb, off, optlen);
	      proto_tree_add_text(subtree, tvb, off, optlen, "time-zone: %s", buf);
	      g_free(buf);
	  }
	  break;
	case OPTION_LIFETIME:
	  if (optlen != 4) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "LIFETIME: malformed option");
	    break;
	  }
	  proto_tree_add_text(subtree, tvb, off, 4,
			      "Lifetime: %d",
			      (guint32)tvb_get_ntohl(tvb, off));
	  break;
	case OPTION_CLIENT_FQDN:
	  if (optlen < 1) {
	    proto_tree_add_text(subtree, tvb, off,
				optlen, "FQDN: malformed option");
	    break;
	  }
	  /*
	   * +-----+-+-+-+
	   * | MBZ |N|O|S|
	   * +-----+-+-+-+
	   */
	  proto_tree_add_item(subtree, hf_fqdn_1, tvb, off, 1, FALSE);
	  proto_tree_add_item(subtree, hf_fqdn_2, tvb, off, 1, FALSE);
	  proto_tree_add_item(subtree, hf_fqdn_3, tvb, off, 1, FALSE);
	  proto_tree_add_item(subtree, hf_fqdn_4, tvb, off, 1, FALSE);
/* 	  proto_tree_add_text(subtree, tvb, off, 1, */
/* 			      "flags: %d", */
/* 			      (guint32)tvb_get_guint8(tvb, off)); */
	  dhcpv6_domain(subtree,tvb, off+1, (guint16) (optlen-1));
	  break;

	case OPTION_IAPREFIX:
	    {
		guint32 preferred_lifetime, valid_lifetime;
		guint8  prefix_length;
		struct e_in6_addr in6;

                if (optlen < 25) {
                   proto_tree_add_text(subtree, tvb, off,
                                       optlen, "IAPREFIX: malformed option");
                   break;
                }

		preferred_lifetime = tvb_get_ntohl(tvb, off);
		valid_lifetime = tvb_get_ntohl(tvb, off + 4);
		prefix_length  = tvb_get_guint8(tvb, off + 8);
		if (preferred_lifetime == DHCPV6_LEASEDURATION_INFINITY) {
			proto_tree_add_text(subtree, tvb, off, 4,
				    "Preferred lifetime: infinity");
		} else {
			proto_tree_add_text(subtree, tvb, off, 4,
				    "Preferred lifetime: %u", preferred_lifetime);
		}
		if (valid_lifetime == DHCPV6_LEASEDURATION_INFINITY) {
			proto_tree_add_text(subtree, tvb, off + 4, 4,
				    "Valid lifetime: infinity");
		} else {
			proto_tree_add_text(subtree, tvb, off + 4, 4,
				    "Valid lifetime: %u", valid_lifetime);
		}
		proto_tree_add_text(subtree, tvb, off + 8, 1,
				    "Prefix length: %d", prefix_length);
		tvb_memcpy(tvb, (guint8 *)&in6, off + 9 , sizeof(in6));
		proto_tree_add_text(subtree, tvb, off + 9,
				    16, "Prefix address: %s",
				    ip6_to_str(&in6));
                
                temp_optlen = 25;
                while ((optlen - temp_optlen) > 0) {
                   temp_optlen += dhcpv6_option(tvb, pinfo, subtree, downstream,
				   off+temp_optlen, off + optlen, at_end);
                   if (*at_end) {
                     /* Bad option - just skip to the end */
                     temp_optlen = optlen;
                   }
                }
	    }
	    break;
	case OPTION_MIP6_HA:
		if (optlen != 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"MIP6_HA: malformed option");
			break;
		}

		tvb_memcpy(tvb, (guint8 *)&in6, off , sizeof(in6));
		proto_tree_add_text(subtree, tvb, off,
			16, "Home Agent: %s", ip6_to_str(&in6));
		break;
	case OPTION_MIP6_HOA:
		if (optlen != 16) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"MIP6_HOA: malformed option");
			break;
		}

		tvb_memcpy(tvb, (guint8 *)&in6, off , sizeof(in6));
		proto_tree_add_text(subtree, tvb, off,
			16, "Home Address: %s", ip6_to_str(&in6));
		break;
	case OPTION_NAI:
		if (optlen < 4) {
			proto_tree_add_text(subtree, tvb, off, optlen,
				"NAI: malformed option");
			break;
		}
		proto_tree_add_text(subtree, tvb, off, optlen,
			"NAI : %s", tvb_get_ptr(tvb, off, optlen - 2));
		break;
	}

	return 4 + optlen;
}


static void
dissect_dhcpv6(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
    gboolean downstream, int off, int eoff)
{
	proto_tree *bp_tree = NULL;
	proto_item *ti;
	guint8 msgtype, hop_count ;
	guint32 xid;
	struct e_in6_addr in6;
	gboolean at_end;

	downstream = 0; /* feature reserved */

	msgtype = tvb_get_guint8(tvb, off);

	if (tree) {
		ti = proto_tree_add_item(tree, proto_dhcpv6, tvb, 0, -1, FALSE);
		bp_tree = proto_item_add_subtree(ti, ett_dhcpv6);
        }

        if (msgtype == RELAY_FORW || msgtype == RELAY_REPLY) {
           
           if (!off) {
              if (check_col(pinfo->cinfo, COL_INFO)) {
                 col_set_str(pinfo->cinfo, COL_INFO,
                             val_to_str(msgtype,
                                        msgtype_vals,
                                        "Message Type %u"));
              }
	   }

           proto_tree_add_uint(bp_tree, hf_dhcpv6_msgtype, tvb, off, 1, msgtype);

           hop_count = tvb_get_guint8(tvb, off+1);
           proto_tree_add_text(bp_tree, tvb, off+1, 1, "Hop count: %d", hop_count);

           tvb_memcpy(tvb, (guint8 *)&in6, off+2, sizeof(in6));
           proto_tree_add_text(bp_tree, tvb, off+2, sizeof(in6), 
                               "Link-address: %s",ip6_to_str(&in6));

           tvb_memcpy(tvb, (guint8 *)&in6, off+18, sizeof(in6));
           proto_tree_add_text(bp_tree, tvb, off+18, sizeof(in6), 
                               "Peer-address: %s",ip6_to_str(&in6));

           off += 34;
        } else {
        
	   xid = tvb_get_ntohl(tvb, off) & 0x00ffffff;

           if (!off) {
              if (check_col(pinfo->cinfo, COL_INFO)) {
                 col_set_str(pinfo->cinfo, COL_INFO,
                             val_to_str(msgtype,
                                        msgtype_vals,
                                        "Message Type %u"));
              }
           }

	   if (tree) {
		   proto_tree_add_uint(bp_tree, hf_dhcpv6_msgtype, tvb, off, 1,
			   msgtype);
		   proto_tree_add_text(bp_tree, tvb, off+1, 3, "Transaction-ID: 0x%08x", xid);
#if 0
		   tvb_memcpy(tvb, (guint8 *)&in6, 4, sizeof(in6));
		   proto_tree_add_text(bp_tree, tvb, 4, sizeof(in6),
			   "Server address: %s", ip6_to_str(&in6));
#endif
	   }

	   off += 4;
	}

	at_end = FALSE;
	while (off < eoff && !at_end)
		off += dhcpv6_option(tvb, pinfo, bp_tree, downstream, off, eoff, &at_end);
}

static void
dissect_dhcpv6_downstream(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	if (check_col(pinfo->cinfo, COL_PROTOCOL))
		col_set_str(pinfo->cinfo, COL_PROTOCOL, "DHCPv6");
	if (check_col(pinfo->cinfo, COL_INFO))
		col_clear(pinfo->cinfo, COL_INFO);
	dissect_dhcpv6(tvb, pinfo, tree, TRUE, 0, tvb_reported_length(tvb));
}

static void
dissect_dhcpv6_upstream(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	if (check_col(pinfo->cinfo, COL_PROTOCOL))
		col_set_str(pinfo->cinfo, COL_PROTOCOL, "DHCPv6");
	if (check_col(pinfo->cinfo, COL_INFO))
		col_clear(pinfo->cinfo, COL_INFO);
	dissect_dhcpv6(tvb, pinfo, tree, FALSE, 0, tvb_reported_length(tvb));
}


void
proto_register_dhcpv6(void)
{
  static hf_register_info hf[] = {

    { &hf_dhcpv6_msgtype,
      { "Message type",			"dhcpv6.msgtype",	 FT_UINT8,
         BASE_DEC, 			VALS(msgtype_vals),   0x0,
      	"", HFILL }},
    { &hf_fqdn_1,
      { "Reserved", "", FT_UINT8, BASE_HEX, NULL, 0xF8, "", HFILL}},
    { &hf_fqdn_2,
      { "N", "", FT_BOOLEAN, 8, TFS(&fqdn_n), 0x4, "", HFILL}},
    { &hf_fqdn_3,
      { "O", "", FT_BOOLEAN, 8, TFS(&fqdn_o), 0x2, "", HFILL}},
    { &hf_fqdn_4,
      { "S", "", FT_BOOLEAN, 8, TFS(&fqdn_s), 0x1, "", HFILL}}
    
  };
  static gint *ett[] = {
    &ett_dhcpv6,
    &ett_dhcpv6_option,
  };

  proto_dhcpv6 = proto_register_protocol("DHCPv6", "DHCPv6", "dhcpv6");
  proto_register_field_array(proto_dhcpv6, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_dhcpv6(void)
{
  dissector_handle_t dhcpv6_handle;

  dhcpv6_handle = create_dissector_handle(dissect_dhcpv6_downstream,
	proto_dhcpv6);
  dissector_add("udp.port", UDP_PORT_DHCPV6_DOWNSTREAM, dhcpv6_handle);
  dhcpv6_handle = create_dissector_handle(dissect_dhcpv6_upstream,
	proto_dhcpv6);
  dissector_add("udp.port", UDP_PORT_DHCPV6_UPSTREAM, dhcpv6_handle);
}
