/* packet-ip.c
 * Routines for IP and miscellaneous IP protocol packet disassembly
 *
 * $Id: packet-ip.c 37070 2011-05-12 10:27:02Z stig $
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Wednesday, January 17, 2006
 * Support for the CIPSO IPv4 option
 * (http://sourceforge.net/docman/display_doc.php?docid=34650&group_id=174379)
 * by   Paul Moore <paul.moore@hp.com>
 *
 * 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/addr_resolv.h>
#include <epan/ipproto.h>
#include <epan/ip_opts.h>
#include <epan/prefs.h>
#include <epan/reassemble.h>
#include <epan/etypes.h>
#include <epan/greproto.h>
#include <epan/ppptypes.h>
#include <epan/llcsaps.h>
#include <epan/aftypes.h>
#include <epan/arcnet_pids.h>
#include <epan/in_cksum.h>
#include <epan/nlpid.h>
#include <epan/tap.h>
#include <epan/emem.h>
#include <epan/expert.h>

#include "packet-ip.h"
#include "packet-ipsec.h"

#ifdef HAVE_GEOIP
#include "GeoIP.h"
#include <epan/geoip_db.h>
#endif /* HAVE_GEOIP */


static int ip_tap = -1;

/* Decode the old IPv4 TOS field as the DiffServ DS Field (RFC2474/2475) */
static gboolean g_ip_dscp_actif = TRUE;

/* Defragment fragmented IP datagrams */
static gboolean ip_defragment = TRUE;

/* Place IP summary in proto tree */
static gboolean ip_summary_in_tree = TRUE;

/* Perform IP checksum */
static gboolean ip_check_checksum = TRUE;

/* Assume TSO and correct zero-length IP packets */
static gboolean ip_tso_supported = TRUE;

#ifdef HAVE_GEOIP
/* Look up addresses in GeoIP */
static gboolean ip_use_geoip = FALSE;
#endif /* HAVE_GEOIP */

/* Interpret the reserved flag as security flag (RFC 3514) */
static gboolean ip_security_flag = FALSE;

static int proto_ip = -1;
static int hf_ip_version = -1;
static int hf_ip_hdr_len = -1;
static int hf_ip_dsfield = -1;
static int hf_ip_dsfield_dscp = -1;
static int hf_ip_dsfield_ecn = -1;
static int hf_ip_tos = -1;
static int hf_ip_tos_precedence = -1;
static int hf_ip_tos_delay = -1;
static int hf_ip_tos_throughput = -1;
static int hf_ip_tos_reliability = -1;
static int hf_ip_tos_cost = -1;
static int hf_ip_len = -1;
static int hf_ip_id = -1;
static int hf_ip_dst = -1;
static int hf_ip_dst_host = -1;
static int hf_ip_src = -1;
static int hf_ip_src_host = -1;
static int hf_ip_addr = -1;
static int hf_ip_host = -1;
static int hf_ip_flags = -1;
static int hf_ip_flags_sf = -1;
static int hf_ip_flags_rf = -1;
static int hf_ip_flags_df = -1;
static int hf_ip_flags_mf = -1;
static int hf_ip_frag_offset = -1;
static int hf_ip_ttl = -1;
static int hf_ip_proto = -1;
static int hf_ip_checksum = -1;
static int hf_ip_checksum_good = -1;
static int hf_ip_checksum_bad = -1;
static int hf_ip_fragments = -1;
static int hf_ip_fragment = -1;
static int hf_ip_fragment_overlap = -1;
static int hf_ip_fragment_overlap_conflict = -1;
static int hf_ip_fragment_multiple_tails = -1;
static int hf_ip_fragment_too_long_fragment = -1;
static int hf_ip_fragment_error = -1;
static int hf_ip_fragment_count = -1;
static int hf_ip_reassembled_in = -1;
static int hf_ip_reassembled_length = -1;

#ifdef HAVE_GEOIP
static int hf_geoip_country = -1;
static int hf_geoip_city = -1;
static int hf_geoip_org = -1;
static int hf_geoip_isp = -1;
static int hf_geoip_asnum = -1;
static int hf_geoip_lat = -1;
static int hf_geoip_lon = -1;
static int hf_geoip_src_country = -1;
static int hf_geoip_src_city = -1;
static int hf_geoip_src_org = -1;
static int hf_geoip_src_isp = -1;
static int hf_geoip_src_asnum = -1;
static int hf_geoip_src_lat = -1;
static int hf_geoip_src_lon = -1;
static int hf_geoip_dst_country = -1;
static int hf_geoip_dst_city = -1;
static int hf_geoip_dst_org = -1;
static int hf_geoip_dst_isp = -1;
static int hf_geoip_dst_asnum = -1;
static int hf_geoip_dst_lat = -1;
static int hf_geoip_dst_lon = -1;
#endif /* HAVE_GEOIP */

static gint ett_ip = -1;
static gint ett_ip_dsfield = -1;
static gint ett_ip_tos = -1;
static gint ett_ip_off = -1;
static gint ett_ip_options = -1;
static gint ett_ip_option_sec = -1;
static gint ett_ip_option_route = -1;
static gint ett_ip_option_timestamp = -1;
static gint ett_ip_option_cipso = -1;
static gint ett_ip_fragments = -1;
static gint ett_ip_fragment  = -1;
static gint ett_ip_checksum = -1;

#ifdef HAVE_GEOIP
static gint ett_geoip_info = -1;
#endif /* HAVE_GEOIP */

static const fragment_items ip_frag_items = {
	&ett_ip_fragment,
	&ett_ip_fragments,
	&hf_ip_fragments,
	&hf_ip_fragment,
	&hf_ip_fragment_overlap,
	&hf_ip_fragment_overlap_conflict,
	&hf_ip_fragment_multiple_tails,
	&hf_ip_fragment_too_long_fragment,
	&hf_ip_fragment_error,
	&hf_ip_fragment_count,
	&hf_ip_reassembled_in,
	&hf_ip_reassembled_length,
	"IPv4 fragments"
};

static dissector_table_t ip_dissector_table;

static dissector_handle_t ipv6_handle;
static dissector_handle_t data_handle;
static dissector_handle_t tapa_handle;


/* IP structs and definitions */

/* Offsets of fields within an IP header. */
#define	IPH_V_HL	0
#define	IPH_TOS		1
#define	IPH_LEN		2
#define	IPH_ID		4
#define	IPH_TTL		6
#define	IPH_OFF		8
#define	IPH_P		9
#define	IPH_SUM		10
#define	IPH_SRC		12
#define	IPH_DST		16

/* Minimum IP header length. */
#define	IPH_MIN_LEN	20

/* Width (in bits) of the fragment offset IP header field */
#define IP_OFFSET_WIDTH   13

/* Width (in bits) of the flags IP header field */
#define IP_FLAGS_WIDTH    3

/* IP flags. */
#define IP_RF		0x8000		/* Flag: "Reserved bit"		*/
#define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
#define IP_MF		0x2000		/* Flag: "More Fragments"	*/
#define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/

/* Differentiated Services Field. See RFCs 2474, 2597 and 2598. */
#define IPDSFIELD_DSCP_MASK     0xFC
#define IPDSFIELD_ECN_MASK     0x03
#define IPDSFIELD_DSCP_SHIFT	2
#define IPDSFIELD_DSCP(dsfield)	(((dsfield)&IPDSFIELD_DSCP_MASK)>>IPDSFIELD_DSCP_SHIFT)
#define IPDSFIELD_ECN(dsfield)	((dsfield)&IPDSFIELD_ECN_MASK)
#define IPDSFIELD_DSCP_DEFAULT  0x00
#define IPDSFIELD_DSCP_CS1      0x08
#define IPDSFIELD_DSCP_CS2      0x10
#define IPDSFIELD_DSCP_CS3      0x18
#define IPDSFIELD_DSCP_CS4      0x20
#define IPDSFIELD_DSCP_CS5      0x28
#define IPDSFIELD_DSCP_CS6      0x30
#define IPDSFIELD_DSCP_CS7      0x38
#define IPDSFIELD_DSCP_AF11     0x0A
#define IPDSFIELD_DSCP_AF12     0x0C
#define IPDSFIELD_DSCP_AF13     0x0E
#define IPDSFIELD_DSCP_AF21     0x12
#define IPDSFIELD_DSCP_AF22     0x14
#define IPDSFIELD_DSCP_AF23     0x16
#define IPDSFIELD_DSCP_AF31     0x1A
#define IPDSFIELD_DSCP_AF32     0x1C
#define IPDSFIELD_DSCP_AF33     0x1E
#define IPDSFIELD_DSCP_AF41     0x22
#define IPDSFIELD_DSCP_AF42     0x24
#define IPDSFIELD_DSCP_AF43     0x26
#define IPDSFIELD_DSCP_EF       0x2E
#define IPDSFIELD_ECT_NOT       0x00
#define IPDSFIELD_ECT_1         0x01
#define IPDSFIELD_ECT_0         0x02
#define IPDSFIELD_CE            0x03

/* IP TOS, superseded by the DS Field, RFC 2474. */
#define IPTOS_TOS_MASK    0x1E
#define IPTOS_TOS(tos)    ((tos) & IPTOS_TOS_MASK)
#define IPTOS_NONE        0x00
#define IPTOS_LOWCOST     0x02
#define IPTOS_RELIABILITY 0x04
#define IPTOS_THROUGHPUT  0x08
#define IPTOS_LOWDELAY    0x10
#define IPTOS_SECURITY    0x1E

#define IPTOS_PREC_MASK		0xE0
#define IPTOS_PREC_SHIFT	5
#define IPTOS_PREC(tos)		(((tos)&IPTOS_PREC_MASK)>>IPTOS_PREC_SHIFT)
#define IPTOS_PREC_NETCONTROL           7
#define IPTOS_PREC_INTERNETCONTROL      6
#define IPTOS_PREC_CRITIC_ECP           5
#define IPTOS_PREC_FLASHOVERRIDE        4
#define IPTOS_PREC_FLASH                3
#define IPTOS_PREC_IMMEDIATE            2
#define IPTOS_PREC_PRIORITY             1
#define IPTOS_PREC_ROUTINE              0

/* IP options */
#define IPOPT_COPY		0x80

#define	IPOPT_CONTROL		0x00
#define	IPOPT_RESERVED1		0x20
#define	IPOPT_MEASUREMENT	0x40
#define	IPOPT_RESERVED2		0x60

#define IPOPT_END	(0 |IPOPT_CONTROL)
#define IPOPT_NOOP	(1 |IPOPT_CONTROL)
#define IPOPT_SEC	(2 |IPOPT_CONTROL|IPOPT_COPY)
#define IPOPT_LSRR	(3 |IPOPT_CONTROL|IPOPT_COPY)
#define IPOPT_TIMESTAMP	(4 |IPOPT_MEASUREMENT)
#define IPOPT_CIPSO	(6 |IPOPT_CONTROL|IPOPT_COPY)
#define IPOPT_RR	(7 |IPOPT_CONTROL)
#define IPOPT_SID	(8 |IPOPT_CONTROL|IPOPT_COPY)
#define IPOPT_SSRR	(9 |IPOPT_CONTROL|IPOPT_COPY)
#define IPOPT_RA	(20|IPOPT_CONTROL|IPOPT_COPY)
#define IPOPT_QS	(25|IPOPT_CONTROL)

/* IP option lengths */
#define IPOLEN_SEC      11
#define IPOLEN_LSRR_MIN 3
#define IPOLEN_TIMESTAMP_MIN 5
#define IPOLEN_RR_MIN   3
#define IPOLEN_SID      4
#define IPOLEN_SSRR_MIN 3
#define IPOLEN_RA       4
#define IPOLEN_QS       8
#define IPOLEN_CIPSO_MIN 10

#define IPSEC_UNCLASSIFIED	0x0000
#define	IPSEC_CONFIDENTIAL	0xF135
#define	IPSEC_EFTO		0x789A
#define	IPSEC_MMMM		0xBC4D
#define	IPSEC_RESTRICTED	0xAF13
#define	IPSEC_SECRET		0xD788
#define	IPSEC_TOPSECRET		0x6BC5
#define	IPSEC_RESERVED1		0x35E2
#define	IPSEC_RESERVED2		0x9AF1
#define	IPSEC_RESERVED3		0x4D78
#define	IPSEC_RESERVED4		0x24BD
#define	IPSEC_RESERVED5		0x135E
#define	IPSEC_RESERVED6		0x89AF
#define	IPSEC_RESERVED7		0xC4D6
#define	IPSEC_RESERVED8		0xE26B

#define	IPOPT_TS_TSONLY		0		/* timestamps only */
#define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
#define	IPOPT_TS_PRESPEC	3		/* specified modules only */

#define IPLOCAL_NETWRK_CTRL_BLK_VRRP_ADDR       0xE0000012
#define IPLOCAL_NETWRK_CTRL_BLK_VRRP_TTL        0xFF
#define IPLOCAL_NETWRK_CTRL_BLK_GLPB_ADDR       0xE0000066
#define IPLOCAL_NETWRK_CTRL_BLK_GLPB_TTL        0XFF
#define IPLOCAL_NETWRK_CTRL_BLK_MDNS_ADDR       0xE00000FB
#define IPLOCAL_NETWRK_CTRL_BLK_MDNS_TTL        0XFF
#define IPLOCAL_NETWRK_CTRL_BLK_LLMNR_ADDR      0xE00000FC

#define IPLOCAL_NETWRK_CTRL_BLK_ANY_TTL         0x1000 /* larger than max ttl */
#define IPLOCAL_NETWRK_CTRL_BLK_DEFAULT_TTL     0X01

/* Return true if the address is in the 224.0.0.0/24 network block */
#define is_a_local_network_control_block_addr(addr) \
  ((addr & 0xffffff00) == 0xe0000000)

/* Return true if the address is in the 224.0.0.0/4 network block */
#define is_a_multicast_addr(addr) \
  ((addr & 0xf0000000) == 0xe0000000)

/*
 * defragmentation of IPv4
 */
static GHashTable *ip_fragment_table = NULL;
static GHashTable *ip_reassembled_table = NULL;

static void
ip_defragment_init(void)
{
  fragment_table_init(&ip_fragment_table);
  reassembled_table_init(&ip_reassembled_table);
}

void
capture_ip(const guchar *pd, int offset, int len, packet_counts *ld) {
  if (!BYTES_ARE_IN_FRAME(offset, len, IPH_MIN_LEN)) {
    ld->other++;
    return;
  }
  switch (pd[offset + 9]) {
    case IP_PROTO_TCP:
      ld->tcp++;
      break;
    case IP_PROTO_UDP:
    case IP_PROTO_UDPLITE:
      ld->udp++;
      break;
    case IP_PROTO_ICMP:
    case IP_PROTO_ICMPV6:	/* XXX - separate counters? */
      ld->icmp++;
      break;
    case IP_PROTO_SCTP:
      ld->sctp++;
      break;
    case IP_PROTO_OSPF:
      ld->ospf++;
      break;
    case IP_PROTO_GRE:
      ld->gre++;
      break;
    case IP_PROTO_VINES:
      ld->vines++;
      break;
    default:
      ld->other++;
  }
}

#ifdef HAVE_GEOIP
static void
add_geoip_info(proto_tree *tree, tvbuff_t *tvb, gint offset, guint32 src32, guint32 dst32)
{
  guint dbnum, num_dbs;
  int geoip_hf, geoip_src_hf, geoip_dst_hf;
  const char *geoip_src_str, *geoip_dst_str;
  proto_item *geoip_info_item;
  proto_tree *geoip_info_tree;
  proto_item *item;
  guint item_cnt;

  num_dbs = geoip_db_num_dbs();

  geoip_info_item = proto_tree_add_text(tree, tvb, offset + IPH_SRC, 4, "Source GeoIP: ");
  geoip_info_tree = proto_item_add_subtree(geoip_info_item, ett_geoip_info);
  PROTO_ITEM_SET_GENERATED(geoip_info_item);
  item_cnt = 0;

  for (dbnum = 0; dbnum < num_dbs; dbnum++) {
    geoip_src_str = geoip_db_lookup_ipv4(dbnum, src32, NULL);

    switch (geoip_db_type(dbnum)) {
      case GEOIP_COUNTRY_EDITION:
        geoip_hf = hf_geoip_country;
        geoip_src_hf = hf_geoip_src_country;
        break;
      case GEOIP_CITY_EDITION_REV0:
        geoip_hf = hf_geoip_city;
        geoip_src_hf = hf_geoip_src_city;
        break;
      case GEOIP_CITY_EDITION_REV1:
        geoip_hf = hf_geoip_city;
        geoip_src_hf = hf_geoip_src_city;
        break;
      case GEOIP_ORG_EDITION:
        geoip_hf = hf_geoip_org;
        geoip_src_hf = hf_geoip_src_org;
        break;
      case GEOIP_ISP_EDITION:
        geoip_hf = hf_geoip_isp;
        geoip_src_hf = hf_geoip_src_isp;
        break;
      case GEOIP_ASNUM_EDITION:
        geoip_hf = hf_geoip_asnum;
        geoip_src_hf = hf_geoip_src_asnum;
        break;
      case WS_LAT_FAKE_EDITION:
        geoip_hf = hf_geoip_lat;
        geoip_src_hf = hf_geoip_src_lat;
        break;
      case WS_LON_FAKE_EDITION:
        geoip_hf = hf_geoip_lon;
        geoip_src_hf = hf_geoip_src_lon;
        break;
      default:
        continue;
        break;
    }

    if (geoip_src_str) {
      item = proto_tree_add_string_format_value(geoip_info_tree, geoip_src_hf, tvb,
        offset + IPH_SRC, 4, geoip_src_str, "%s", geoip_src_str);
      PROTO_ITEM_SET_GENERATED(item);
      item  = proto_tree_add_string_format_value(geoip_info_tree, geoip_hf, tvb,
        offset + IPH_SRC, 4, geoip_src_str, "%s", geoip_src_str);
      PROTO_ITEM_SET_GENERATED(item);
      PROTO_ITEM_SET_HIDDEN(item);

      item_cnt++;
      proto_item_append_text(geoip_info_item, "%s%s", plurality(item_cnt, "", ", "), geoip_src_str);
    }
  }

  if (item_cnt == 0)
    proto_item_append_text(geoip_info_item, "Unknown");

  geoip_info_item = proto_tree_add_text(tree, tvb, offset + IPH_DST, 4, "Destination GeoIP: ");
  geoip_info_tree = proto_item_add_subtree(geoip_info_item, ett_geoip_info);
  PROTO_ITEM_SET_GENERATED(geoip_info_item);
  item_cnt = 0;

  for (dbnum = 0; dbnum < num_dbs; dbnum++) {
    geoip_dst_str = geoip_db_lookup_ipv4(dbnum, dst32, NULL);

    switch (geoip_db_type(dbnum)) {
      case GEOIP_COUNTRY_EDITION:
        geoip_hf = hf_geoip_country;
        geoip_dst_hf = hf_geoip_dst_country;
        break;
      case GEOIP_CITY_EDITION_REV0:
        geoip_hf = hf_geoip_city;
        geoip_dst_hf = hf_geoip_dst_city;
        break;
      case GEOIP_CITY_EDITION_REV1:
        geoip_hf = hf_geoip_city;
        geoip_dst_hf = hf_geoip_dst_city;
        break;
      case GEOIP_ORG_EDITION:
        geoip_hf = hf_geoip_org;
        geoip_dst_hf = hf_geoip_dst_org;
        break;
      case GEOIP_ISP_EDITION:
        geoip_hf = hf_geoip_isp;
        geoip_dst_hf = hf_geoip_dst_isp;
        break;
      case GEOIP_ASNUM_EDITION:
        geoip_hf = hf_geoip_asnum;
        geoip_dst_hf = hf_geoip_dst_asnum;
        break;
      case WS_LAT_FAKE_EDITION:
        geoip_hf = hf_geoip_lat;
        geoip_dst_hf = hf_geoip_dst_lat;
        break;
      case WS_LON_FAKE_EDITION:
        geoip_hf = hf_geoip_lon;
        geoip_dst_hf = hf_geoip_dst_lon;
        break;
      default:
        continue;
        break;
    }

    if (geoip_dst_str) {
      item = proto_tree_add_string_format_value(geoip_info_tree, geoip_dst_hf, tvb,
        offset + IPH_DST, 4, geoip_dst_str, "%s", geoip_dst_str);
      PROTO_ITEM_SET_GENERATED(item);
      item  = proto_tree_add_string_format_value(geoip_info_tree, geoip_hf, tvb,
        offset + IPH_DST, 4, geoip_dst_str, "%s", geoip_dst_str);
      PROTO_ITEM_SET_GENERATED(item);
      PROTO_ITEM_SET_HIDDEN(item);

      item_cnt++;
      proto_item_append_text(geoip_info_item, "%s%s", plurality(item_cnt, "", ", "), geoip_dst_str);
    }
  }

  if (item_cnt == 0)
    proto_item_append_text(geoip_info_item, "Unknown");
}
#endif /* HAVE_GEOIP */

static void
dissect_ipopt_security(const ip_tcp_opt *optp, tvbuff_t *tvb, int offset,
			guint optlen, packet_info *pinfo _U_,
			proto_tree *opt_tree)
{
  proto_tree *field_tree = NULL;
  proto_item *tf;
  guint      val;
  static const value_string secl_vals[] = {
    {IPSEC_UNCLASSIFIED, "Unclassified"},
    {IPSEC_CONFIDENTIAL, "Confidential"},
    {IPSEC_EFTO,         "EFTO"        },
    {IPSEC_MMMM,         "MMMM"        },
    {IPSEC_RESTRICTED,   "Restricted"  },
    {IPSEC_SECRET,       "Secret"      },
    {IPSEC_TOPSECRET,    "Top secret"  },
    {IPSEC_RESERVED1,    "Reserved"    },
    {IPSEC_RESERVED2,    "Reserved"    },
    {IPSEC_RESERVED3,    "Reserved"    },
    {IPSEC_RESERVED4,    "Reserved"    },
    {IPSEC_RESERVED5,    "Reserved"    },
    {IPSEC_RESERVED6,    "Reserved"    },
    {IPSEC_RESERVED7,    "Reserved"    },
    {IPSEC_RESERVED8,    "Reserved"    },
    {0,                  NULL          } };

  tf = proto_tree_add_text(opt_tree, tvb, offset,      optlen, "%s:", optp->name);
  field_tree = proto_item_add_subtree(tf, *optp->subtree_index);
  offset += 2;

  val = tvb_get_ntohs(tvb, offset);
  proto_tree_add_text(field_tree, tvb, offset,       2,
              "Security: %s", val_to_str(val, secl_vals, "Unknown (0x%x)"));
  offset += 2;

  val = tvb_get_ntohs(tvb, offset);
  proto_tree_add_text(field_tree, tvb, offset,         2,
              "Compartments: %u", val);
  offset += 2;

  proto_tree_add_text(field_tree, tvb, offset,         2,
              "Handling restrictions: %c%c",
	      tvb_get_guint8(tvb, offset),
	      tvb_get_guint8(tvb, offset + 1));
  offset += 2;

  proto_tree_add_text(field_tree, tvb, offset,         3,
              "Transmission control code: %c%c%c",
	      tvb_get_guint8(tvb, offset),
	      tvb_get_guint8(tvb, offset + 1),
	      tvb_get_guint8(tvb, offset + 2));
}

/* USHRT_MAX can hold at most 5 (base 10) digits (6 for the NULL byte) */
#define USHRT_MAX_STRLEN 6

/* Maximum CIPSO tag length:
 * (IP hdr max)60 - (IPv4 hdr std)20 - (CIPSO base)6 = 34 */
#define CIPSO_TAG_LEN_MAX 34

/* The Commercial IP Security Option (CIPSO) is defined in IETF draft
 * draft-ietf-cipso-ipsecurity-01.txt and FIPS 188, a copy of both documents
 * can be found at the NetLabel project page, http://netlabel.sf.net. */
static void
dissect_ipopt_cipso(const ip_tcp_opt *optp, tvbuff_t *tvb, int offset,
                    guint optlen, packet_info *pinfo _U_, proto_tree *opt_tree)
{
  proto_tree *field_tree = NULL;
  proto_item *tf;
  guint      tagtype, taglen;
  int        offset_max = offset + optlen;

  tf = proto_tree_add_text(opt_tree, tvb, offset, optlen, "%s", optp->name);
  field_tree = proto_item_add_subtree(tf, *optp->subtree_index);
  offset += 2;

  proto_tree_add_text(field_tree, tvb, offset, 4, "DOI: %u",
		      tvb_get_ntohl(tvb, offset));
  offset += 4;

  /* loop through all of the tags in the CIPSO option */
  while (offset < offset_max) {
    tagtype = tvb_get_guint8(tvb, offset);

    if ((offset + 1) < offset_max)
      taglen = tvb_get_guint8(tvb, offset + 1);
    else
      taglen = 1;

    switch (tagtype) {
    case 0:
      /* padding - skip this tag */
      offset += 1;
      continue;
    case 1:
      /* restrictive bitmap, see CIPSO draft section 3.4.2 for tag format */
      if ((taglen < 4) || (taglen > CIPSO_TAG_LEN_MAX) ||
	  ((offset + (int)taglen - 1) > offset_max)) {
	proto_tree_add_text(field_tree, tvb, offset, offset_max - offset,
			    "Malformed CIPSO tag");
        return;
      }

      proto_tree_add_text(field_tree, tvb, offset, 1,
                          "Tag Type: Restrictive Category Bitmap (%u)",
			  tagtype);

      /* skip past alignment octet */
      offset += 3;

      proto_tree_add_text(field_tree, tvb, offset, 1, "Sensitivity Level: %u",
			  tvb_get_guint8(tvb, offset));
      offset += 1;

      if (taglen > 4) {
	guint bit_spot = 0;
	guint byte_spot = 0;
	unsigned char bitmask;
	char *cat_str;
	char *cat_str_tmp = ep_alloc(USHRT_MAX_STRLEN);
	size_t cat_str_len;
	const guint8 *val_ptr = tvb_get_ptr(tvb, offset, taglen - 4);

	/* this is just a guess regarding string size, but we grow it below
	 * if needed */
	cat_str_len = 256;
	cat_str = ep_alloc0(cat_str_len);

	/* we checked the length above so the highest category value
	 * possibile here is 240 */
	while (byte_spot < (taglen - 4)) {
	  bitmask = 0x80;
	  bit_spot = 0;
	  while (bit_spot < 8) {
	    if (val_ptr[byte_spot] & bitmask) {
	      g_snprintf(cat_str_tmp, USHRT_MAX_STRLEN, "%u",
		       byte_spot * 8 + bit_spot);
	      if (cat_str_len < (strlen(cat_str) + 2 + USHRT_MAX_STRLEN)) {
		char *cat_str_new;
		while (cat_str_len < (strlen(cat_str) + 2 + USHRT_MAX_STRLEN))
		  cat_str_len += cat_str_len;
		cat_str_new = ep_alloc(cat_str_len);
		g_strlcpy(cat_str_new, cat_str, cat_str_len);
		cat_str_new[cat_str_len - 1] = '\0';
		cat_str = cat_str_new;
	      }
	      if (cat_str[0] != '\0')
		g_strlcat(cat_str, ",", cat_str_len);
	      g_strlcat(cat_str, cat_str_tmp, cat_str_len);
	    }
	    bit_spot++;
	    bitmask >>= 1;
	  }
	  byte_spot++;
	}

	if (cat_str)
	  proto_tree_add_text(field_tree, tvb, offset, taglen - 4,
			      "Categories: %s", cat_str);
	else
	  proto_tree_add_text(field_tree, tvb, offset, taglen - 4,
			      "Categories: ERROR PARSING CATEGORIES");

        offset += taglen - 4;
      }
      break;
    case 2:
      /* enumerated categories, see CIPSO draft section 3.4.3 for tag format */
      if ((taglen < 4) || (taglen > CIPSO_TAG_LEN_MAX) ||
	  ((offset + (int)taglen - 1) > offset_max)) {
	proto_tree_add_text(field_tree, tvb, offset, offset_max - offset,
			    "Malformed CIPSO tag");
        return;
      }

      proto_tree_add_text(field_tree, tvb, offset, 1,
                          "Tag Type: Enumerated Categories (%u)", tagtype);

      /* skip past alignment octet */
      offset += 3;

      /* sensitvity level */
      proto_tree_add_text(field_tree, tvb, offset, 1, "Sensitivity Level: %u",
			  tvb_get_guint8(tvb, offset));
      offset += 1;

      if (taglen > 4) {
	int offset_max_cat = offset + taglen - 4;
	char *cat_str = ep_alloc0(USHRT_MAX_STRLEN * 15);
	char *cat_str_tmp = ep_alloc(USHRT_MAX_STRLEN);

	while ((offset + 2) <= offset_max_cat) {
	  g_snprintf(cat_str_tmp, USHRT_MAX_STRLEN, "%u",
		   tvb_get_ntohs(tvb, offset));
	  offset += 2;
	  if (cat_str[0] != '\0')
	    g_strlcat(cat_str, ",", USHRT_MAX_STRLEN * 15);
	  g_strlcat(cat_str, cat_str_tmp, USHRT_MAX_STRLEN * 15);
	}

	proto_tree_add_text(field_tree, tvb, offset - taglen + 4, taglen - 4,
			    "Categories: %s", cat_str);
      }
      break;
    case 5:
      /* ranged categories, see CIPSO draft section 3.4.4 for tag format */
      if ((taglen < 4) || (taglen > CIPSO_TAG_LEN_MAX) ||
	  ((offset + (int)taglen - 1) > offset_max)) {
	proto_tree_add_text(field_tree, tvb, offset, offset_max - offset,
			    "Malformed CIPSO tag");
        return;
      }

      proto_tree_add_text(field_tree, tvb, offset, 1,
                          "Tag Type: Ranged Categories (%u)", tagtype);

      /* skip past alignment octet */
      offset += 3;

      /* sensitvity level */
      proto_tree_add_text(field_tree, tvb, offset, 1, "Sensitivity Level: %u",
			  tvb_get_guint8(tvb, offset));
      offset += 1;

      if (taglen > 4) {
	guint16 cat_low, cat_high;
	int offset_max_cat = offset + taglen - 4;
	char *cat_str = ep_alloc0(USHRT_MAX_STRLEN * 16);
	char *cat_str_tmp = ep_alloc(USHRT_MAX_STRLEN * 2);

	while ((offset + 2) <= offset_max_cat) {
	  cat_high = tvb_get_ntohs(tvb, offset);
	  if ((offset + 4) <= offset_max_cat) {
	    cat_low = tvb_get_ntohs(tvb, offset + 2);
	    offset += 4;
	  } else {
	    cat_low = 0;
	    offset += 2;
	  }
	  if (cat_low != cat_high)
	    g_snprintf(cat_str_tmp, USHRT_MAX_STRLEN * 2, "%u-%u",
		     cat_high, cat_low);
	  else
	    g_snprintf(cat_str_tmp, USHRT_MAX_STRLEN * 2, "%u", cat_high);
	  if (cat_str[0] != '\0')
	    g_strlcat(cat_str, ",", USHRT_MAX_STRLEN * 16);
	  g_strlcat(cat_str, cat_str_tmp, USHRT_MAX_STRLEN * 16);
	}

	proto_tree_add_text(field_tree, tvb, offset - taglen + 4, taglen - 4,
			    "Categories: %s", cat_str);
      }
      break;
    case 6:
      /* permissive categories, see FIPS 188 section 6.9 for tag format */
      if ((taglen < 4) || (taglen > CIPSO_TAG_LEN_MAX) ||
	  ((offset + (int)taglen - 1) > offset_max)) {
	proto_tree_add_text(field_tree, tvb, offset, offset_max - offset,
			    "Malformed CIPSO tag");
        return;
      }

      proto_tree_add_text(field_tree, tvb, offset, 1,
                          "Tag Type: Permissive Categories (%u)", tagtype);
      proto_tree_add_text(field_tree, tvb, offset + 2, taglen - 2, "Tag data");
      offset += taglen;
      break;
    case 7:
      /* free form, see FIPS 188 section 6.10 for tag format */
      if ((taglen < 2) || (taglen > CIPSO_TAG_LEN_MAX) ||
	  ((offset + (int)taglen - 1) > offset_max)) {
	proto_tree_add_text(field_tree, tvb, offset, offset_max - offset,
			    "Malformed CIPSO tag");
        return;
      }

      proto_tree_add_text(field_tree, tvb, offset, 1,
                          "Tag Type: Free Form (%u)", tagtype);
      proto_tree_add_text(field_tree, tvb, offset + 2, taglen - 2, "Tag data");
      offset += taglen;
      break;
    default:
      /* unknown tag - stop parsing this IPv4 option */
      if ((offset + 1) <= offset_max) {
	taglen = tvb_get_guint8(tvb, offset + 1);
	proto_tree_add_text(field_tree, tvb, offset, 1,
			    "Tag Type: Unknown (%u) (%u bytes)",
			    tagtype, taglen);
	return;
      }
      proto_tree_add_text(field_tree, tvb, offset, 1,
			  "Tag Type: Unknown (%u) (invalid format)",
			  tagtype);
      return;
    }
  }
}

static void
dissect_ipopt_route(const ip_tcp_opt *optp, tvbuff_t *tvb, int offset,
			guint optlen, packet_info *pinfo _U_,
			proto_tree *opt_tree)
{
  proto_tree *field_tree = NULL;
  proto_item *tf;
  int ptr;
  int optoffset = 0;
  guint32 addr;

  tf = proto_tree_add_text(opt_tree, tvb, offset,      optlen, "%s (%u bytes)",
				optp->name, optlen);
  field_tree = proto_item_add_subtree(tf, *optp->subtree_index);

  optoffset += 2;	/* skip past type and length */
  optlen -= 2;		/* subtract size of type and length */

  ptr = tvb_get_guint8(tvb, offset + optoffset);
  proto_tree_add_text(field_tree, tvb, offset + optoffset, 1,
              "Pointer: %d%s", ptr,
              ((ptr < 4) ? " (points before first address)" :
               ((ptr & 3) ? " (points to middle of address)" : "")));
  optoffset++;
  optlen--;
  ptr--;	/* ptr is 1-origin */

  while (optlen > 0) {
    if (optlen < 4) {
      proto_tree_add_text(field_tree, tvb, offset,      optlen,
        "(suboption would go past end of option)");
      break;
    }

    addr = tvb_get_ipv4(tvb, offset + optoffset);
    proto_tree_add_text(field_tree, tvb, offset + optoffset, 4,
              "%s%s",
              ((addr == 0) ? "-" : (const char *)get_hostname(addr)),
              ((optoffset == ptr) ? " <- (current)" : ""));
    optoffset += 4;
    optlen -= 4;
  }
}

static void
dissect_ipopt_sid(const ip_tcp_opt *optp, tvbuff_t *tvb, int offset,
			guint optlen, packet_info *pinfo _U_,
			proto_tree *opt_tree)
{
  proto_tree_add_text(opt_tree, tvb, offset,      optlen,
    "%s: %u", optp->name, tvb_get_ntohs(tvb, offset + 2));
  return;
}

static void
dissect_ipopt_timestamp(const ip_tcp_opt *optp, tvbuff_t *tvb,
    int offset, guint optlen, packet_info *pinfo _U_, proto_tree *opt_tree)
{
  proto_tree *field_tree = NULL;
  proto_item *tf;
  int        ptr;
  int        optoffset = 0;
  int        flg;
  static const value_string flag_vals[] = {
    {IPOPT_TS_TSONLY,    "Time stamps only"                      },
    {IPOPT_TS_TSANDADDR, "Time stamp and address"                },
    {IPOPT_TS_PRESPEC,   "Time stamps for prespecified addresses"},
    {0,                  NULL                                    } };
  guint32 addr;
  guint ts;

  tf = proto_tree_add_text(opt_tree, tvb, offset,      optlen, "%s:", optp->name);
  field_tree = proto_item_add_subtree(tf, *optp->subtree_index);

  optoffset += 2;	/* skip past type and length */
  optlen -= 2;		/* subtract size of type and length */

  ptr = tvb_get_guint8(tvb, offset + optoffset);
  proto_tree_add_text(field_tree, tvb, offset + optoffset, 1,
              "Pointer: %d%s", ptr,
              ((ptr == 1) ? " (header is full)" :
               (ptr < 5) ? " (points before first address)" :
               (((ptr - 1) & 3) ? " (points to middle of field)" : "")));
  optoffset++;
  optlen--;
  ptr--;	/* ptr is 1-origin */

  flg = tvb_get_guint8(tvb, offset + optoffset);
  proto_tree_add_text(field_tree, tvb, offset + optoffset,   1,
        "Overflow: %u", flg >> 4);
  flg &= 0xF;
  proto_tree_add_text(field_tree, tvb, offset + optoffset, 1,
        "Flag: %s", val_to_str(flg, flag_vals, "Unknown (0x%x)"));
  optoffset++;
  optlen--;

  while (optlen > 0) {
    if (flg == IPOPT_TS_TSANDADDR || flg == IPOPT_TS_PRESPEC) {
      if (optlen < 8) {
        proto_tree_add_text(field_tree, tvb, offset + optoffset, optlen,
          "(suboption would go past end of option)");
        break;
      }
      addr = tvb_get_ipv4(tvb, offset + optoffset);
      ts = tvb_get_ntohl(tvb, offset + optoffset + 4);
      optlen -= 8;
      proto_tree_add_text(field_tree, tvb, offset + optoffset,      8,
          "Address = %s, time stamp = %u",
          ((addr == 0) ? "-" :  (const char *)get_hostname(addr)),
          ts);
      optoffset += 8;
    } else {
      if (optlen < 4) {
        proto_tree_add_text(field_tree, tvb, offset + optoffset, optlen,
          "(suboption would go past end of option)");
        break;
      }
      ts = tvb_get_ntohl(tvb, offset + optoffset);
      optlen -= 4;
      proto_tree_add_text(field_tree, tvb, offset + optoffset, 4,
          "Time stamp = %u", ts);
      optoffset += 4;
    }
  }
}

static void
dissect_ipopt_ra(const ip_tcp_opt *optp, tvbuff_t *tvb, int offset,
		guint optlen, packet_info *pinfo _U_, proto_tree *opt_tree)
{
  /* Router-Alert, as defined by RFC2113 */
  int opt = tvb_get_ntohs(tvb, offset + 2);
  static const value_string ra_opts[] = {
	{0, "Every router examines packet"},
	{0, NULL}
  };

  proto_tree_add_text(opt_tree, tvb, offset,      optlen,
    "%s: %s", optp->name, val_to_str(opt, ra_opts, "Unknown (%d)"));
  return;
}

static void
dissect_ipopt_qs(const ip_tcp_opt *optp, tvbuff_t *tvb, int offset,
		guint optlen, packet_info *pinfo _U_, proto_tree *opt_tree)
{
  /* Quick-Start TCP option, as defined by RFC4782 */
  static const value_string qs_rates[] = {
    { 0, "0 bit/s"},
    { 1, "80 kbit/s"},
    { 2, "160 kbit/s"},
    { 3, "320 kbit/s"},
    { 4, "640 kbit/s"},
    { 5, "1.28 Mbit/s"},
    { 6, "2.56 Mbit/s"},
    { 7, "5.12 Mbit/s"},
    { 8, "10.24 Mbit/s"},
    { 9, "20.48 Mbit/s"},
    {10, "40.96 Mbit/s"},
    {11, "81.92 Mbit/s"},
    {12, "163.84 Mbit/s"},
    {13, "327.68 Mbit/s"},
    {14, "655.36 Mbit/s"},
    {15, "1.31072 Gbit/s"},
    {0, NULL}
  };
  static value_string_ext qs_rates_ext = VALUE_STRING_EXT_INIT(qs_rates);

  guint8 command = tvb_get_guint8(tvb, offset + 2);
  guint8 function = command >> 4;
  guint8 rate = command & 0x0f;

  switch (function) {
  case 0x00: /* rate request */
    proto_tree_add_text(opt_tree, tvb, offset,      optlen,
			"%s: Rate request, %s, QS TTL %u", optp->name,
		      val_to_str_ext_const(rate, &qs_rates_ext, "Unknown"),
		      tvb_get_guint8(tvb, offset + 3));
    break;
  case 0x08: /* rate report */
    proto_tree_add_text(opt_tree, tvb, offset,      optlen,
			"%s: Rate report, %s", optp->name,
			val_to_str_ext_const(rate, &qs_rates_ext, "Unknown"));
    break;
  default:
    proto_tree_add_text(opt_tree, tvb, offset,      optlen,
			"%s: Unknown function", optp->name);
  }
}

static const ip_tcp_opt ipopts[] = {
  {
    IPOPT_END,
    "End of Option List (EOL)",
    NULL,
    NO_LENGTH,
    0,
    NULL,
  },
  {
    IPOPT_NOOP,
    "No-Operation (NOP)",
    NULL,
    NO_LENGTH,
    0,
    NULL,
  },
  {
    IPOPT_SEC,
    "Security",
    &ett_ip_option_sec,
    FIXED_LENGTH,
    IPOLEN_SEC,
    dissect_ipopt_security
  },
  {
    IPOPT_SSRR,
    "Strict source route",
    &ett_ip_option_route,
    VARIABLE_LENGTH,
    IPOLEN_SSRR_MIN,
    dissect_ipopt_route
  },
  {
    IPOPT_LSRR,
    "Loose source route",
    &ett_ip_option_route,
    VARIABLE_LENGTH,
    IPOLEN_LSRR_MIN,
    dissect_ipopt_route
  },
  {
    IPOPT_CIPSO,
    "Commercial IP security option",
    &ett_ip_option_cipso,
    VARIABLE_LENGTH,
    IPOLEN_CIPSO_MIN,
    dissect_ipopt_cipso
  },
  {
    IPOPT_RR,
    "Record route",
    &ett_ip_option_route,
    VARIABLE_LENGTH,
    IPOLEN_RR_MIN,
    dissect_ipopt_route
  },
  {
    IPOPT_SID,
    "Stream identifier",
    NULL,
    FIXED_LENGTH,
    IPOLEN_SID,
    dissect_ipopt_sid
  },
  {
    IPOPT_TIMESTAMP,
    "Time stamp",
    &ett_ip_option_timestamp,
    VARIABLE_LENGTH,
    IPOLEN_TIMESTAMP_MIN,
    dissect_ipopt_timestamp
  },
  {
    IPOPT_RA,
    "Router Alert",
    NULL,
    FIXED_LENGTH,
    IPOLEN_RA,
    dissect_ipopt_ra
  },
  {
    IPOPT_QS,
    "Quick-Start",
    NULL,
    FIXED_LENGTH,
    IPOLEN_QS,
    dissect_ipopt_qs
  }
};

#define N_IP_OPTS	array_length(ipopts)

/* Dissect the IP or TCP options in a packet. */
void
dissect_ip_tcp_options(tvbuff_t *tvb, int offset, guint length,
			const ip_tcp_opt *opttab, int nopts, int eol,
			packet_info *pinfo, proto_tree *opt_tree, proto_item *opt_item)
{
  guchar            opt;
  const ip_tcp_opt *optp;
  opt_len_type      len_type;
  unsigned int      optlen;
  const char       *name;
  void            (*dissect)(const struct ip_tcp_opt *, tvbuff_t *,
				int, guint, packet_info *, proto_tree *);
  guint             len, nop_count = 0;

  while (length > 0) {
    opt = tvb_get_guint8(tvb, offset);
    for (optp = &opttab[0]; optp < &opttab[nopts]; optp++) {
      if (optp->optcode == opt)
        break;
    }
    if (optp == &opttab[nopts]) {
      /* We assume that the only NO_LENGTH options are EOL and NOP options,
         so that we can treat unknown options as VARIABLE_LENGTH with a
	 minimum of 2, and at least be able to move on to the next option
	 by using the length in the option. */
      optp = NULL;	/* indicate that we don't know this option */
      len_type = VARIABLE_LENGTH;
      optlen = 2;
      name = ep_strdup_printf("Unknown (0x%02x)", opt);
      dissect = NULL;
      nop_count = 0;
    } else {
      len_type = optp->len_type;
      optlen = optp->optlen;
      name = optp->name;
      dissect = optp->dissect;
      if (opt_item && len_type == NO_LENGTH && optlen == 0 && opt == 1 &&
	  (nop_count == 0 || offset % 4))  /* opt 1 = NOP in both IP and TCP */
      {
	/* Count number of NOP in a row within a uint32 */
	nop_count++;
      } else {
	nop_count = 0;
      }
    }
    --length;      /* account for type byte */
    if (len_type != NO_LENGTH) {
      /* Option has a length. Is it in the packet? */
      if (length == 0) {
        /* Bogus - packet must at least include option code byte and
           length byte! */
        proto_tree_add_text(opt_tree, tvb, offset,      1,
              "%s (length byte past end of options)", name);
        return;
      }
      len = tvb_get_guint8(tvb, offset + 1);  /* total including type, len */
      --length;    /* account for length byte */
      if (len < 2) {
        /* Bogus - option length is too short to include option code and
           option length. */
        proto_tree_add_text(opt_tree, tvb, offset,      2,
              "%s (with too-short option length = %u byte%s)", name,
              len, plurality(len, "", "s"));
        return;
      } else if (len - 2 > length) {
        /* Bogus - option goes past the end of the header. */
        proto_tree_add_text(opt_tree, tvb, offset,      length,
              "%s (option length = %u byte%s says option goes past end of options)",
	      name, len, plurality(len, "", "s"));
        return;
      } else if (len_type == FIXED_LENGTH && len != optlen) {
        /* Bogus - option length isn't what it's supposed to be for this
           option. */
        proto_tree_add_text(opt_tree, tvb, offset,      len,
              "%s (with option length = %u byte%s; should be %u)", name,
              len, plurality(len, "", "s"), optlen);
        return;
      } else if (len_type == VARIABLE_LENGTH && len < optlen) {
        /* Bogus - option length is less than what it's supposed to be for
           this option. */
        proto_tree_add_text(opt_tree, tvb, offset,      len,
              "%s (with option length = %u byte%s; should be >= %u)", name,
              len, plurality(len, "", "s"), optlen);
        return;
      } else {
        if (optp == NULL) {
          proto_tree_add_text(opt_tree, tvb, offset,    len, "%s (%u byte%s)",
				name, len, plurality(len, "", "s"));
        } else {
          if (dissect != NULL) {
            /* Option has a dissector. */
            (*dissect)(optp, tvb, offset,          len, pinfo, opt_tree);
          } else {
            /* Option has no data, hence no dissector. */
            proto_tree_add_text(opt_tree, tvb, offset,  len, "%s", name);
          }
        }
        len -= 2;	/* subtract size of type and length */
        offset += 2 + len;
      }
      length -= len;
    } else {
      proto_tree_add_text(opt_tree, tvb, offset,      1, "%s", name);
      offset += 1;

      if (nop_count == 4 && strcmp (name, "No-Operation (NOP)") == 0) {
	expert_add_info_format(pinfo, opt_item, PI_PROTOCOL, PI_WARN,
			       "4 NOP in a row - a router may have removed some options");
      }
    }
    if (opt == eol)
      break;
  }
}

/* Returns the valid ttl for the group address */
static guint16
local_network_control_block_addr_valid_ttl(guint32 addr)
{
  /* An exception list, as some protocols seem to insist on
   * doing differently:
   */

  /* IETF's VRRP (rfc3768) */
  if (IPLOCAL_NETWRK_CTRL_BLK_VRRP_ADDR == addr)
	return IPLOCAL_NETWRK_CTRL_BLK_VRRP_TTL;
  /* Cisco's GLPB */
  if (IPLOCAL_NETWRK_CTRL_BLK_GLPB_ADDR == addr)
	return IPLOCAL_NETWRK_CTRL_BLK_GLPB_TTL;
  /* mDNS (draft-cheshire-dnsext-multicastdns-07) */
  if (IPLOCAL_NETWRK_CTRL_BLK_MDNS_ADDR == addr)
	return IPLOCAL_NETWRK_CTRL_BLK_MDNS_TTL;
  /* LLMNR (rfc4795) */
  if (IPLOCAL_NETWRK_CTRL_BLK_LLMNR_ADDR == addr)
	return IPLOCAL_NETWRK_CTRL_BLK_ANY_TTL;
  return IPLOCAL_NETWRK_CTRL_BLK_DEFAULT_TTL;
}

const value_string dscp_vals[] = {
		  { IPDSFIELD_DSCP_DEFAULT, "Default"               },
		  { IPDSFIELD_DSCP_CS1,     "Class Selector 1"      },
		  { IPDSFIELD_DSCP_CS2,     "Class Selector 2"      },
		  { IPDSFIELD_DSCP_CS3,     "Class Selector 3"      },
		  { IPDSFIELD_DSCP_CS4,     "Class Selector 4"      },
		  { IPDSFIELD_DSCP_CS5,     "Class Selector 5"      },
		  { IPDSFIELD_DSCP_CS6,     "Class Selector 6"      },
		  { IPDSFIELD_DSCP_CS7,     "Class Selector 7"      },
		  { IPDSFIELD_DSCP_AF11,    "Assured Forwarding 11" },
		  { IPDSFIELD_DSCP_AF12,    "Assured Forwarding 12" },
		  { IPDSFIELD_DSCP_AF13,    "Assured Forwarding 13" },
		  { IPDSFIELD_DSCP_AF21,    "Assured Forwarding 21" },
		  { IPDSFIELD_DSCP_AF22,    "Assured Forwarding 22" },
		  { IPDSFIELD_DSCP_AF23,    "Assured Forwarding 23" },
		  { IPDSFIELD_DSCP_AF31,    "Assured Forwarding 31" },
		  { IPDSFIELD_DSCP_AF32,    "Assured Forwarding 32" },
		  { IPDSFIELD_DSCP_AF33,    "Assured Forwarding 33" },
		  { IPDSFIELD_DSCP_AF41,    "Assured Forwarding 41" },
		  { IPDSFIELD_DSCP_AF42,    "Assured Forwarding 42" },
		  { IPDSFIELD_DSCP_AF43,    "Assured Forwarding 43" },
		  { IPDSFIELD_DSCP_EF,      "Expedited Forwarding"  },
		  { 0,                      NULL                    } };

const value_string ecn_vals[] = {
		  { IPDSFIELD_ECT_NOT, "Not-ECT (Not ECN-Capable Transport)" },
		  { IPDSFIELD_ECT_1,   "ECT(1) (ECN-Capable Transport)"      },
		  { IPDSFIELD_ECT_0,   "ECT(0) (ECN-Capable Transport)"      },
		  { IPDSFIELD_CE,      "CE (Congestion Experienced)"         },
		  { 0,                 NULL                                  } };

static const value_string precedence_vals[] = {
		  { IPTOS_PREC_ROUTINE,         "routine"              },
		  { IPTOS_PREC_PRIORITY,        "priority"             },
		  { IPTOS_PREC_IMMEDIATE,       "immediate"            },
		  { IPTOS_PREC_FLASH,           "flash"                },
		  { IPTOS_PREC_FLASHOVERRIDE,   "flash override"       },
		  { IPTOS_PREC_CRITIC_ECP,      "CRITIC/ECP"           },
		  { IPTOS_PREC_INTERNETCONTROL, "internetwork control" },
		  { IPTOS_PREC_NETCONTROL,      "network control"      },
		  { 0,                          NULL                   } };

static const value_string iptos_vals[] = {
	{ IPTOS_NONE,		"None" },
	{ IPTOS_LOWCOST,	"Minimize cost" },
	{ IPTOS_RELIABILITY,	"Maximize reliability" },
	{ IPTOS_THROUGHPUT,	"Maximize throughput" },
	{ IPTOS_LOWDELAY,	"Minimize delay" },
	{ IPTOS_SECURITY,	"Maximize security" },
	{ 0,			NULL }
};

static const true_false_string tos_set_low = {
  "Low",
  "Normal"
};

static const true_false_string tos_set_high = {
  "High",
  "Normal"
};

static const true_false_string flags_sf_set_evil = {
  "Evil",
  "Not evil"
};

guint16 ip_checksum(const guint8 *ptr, int len)
{
	vec_t cksum_vec[1];

	cksum_vec[0].ptr = ptr;
	cksum_vec[0].len = len;
	return in_cksum(&cksum_vec[0], 1);
}

static void
dissect_ip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
{
  proto_tree *ip_tree = NULL, *field_tree= NULL;
  proto_item *ti = NULL, *tf;
  guint32    addr;
  int        offset = 0;
  guint      hlen, optlen;
  guint16    flags;
  guint8     nxt;
  guint16    ipsum;
  fragment_data *ipfd_head=NULL;
  tvbuff_t   *next_tvb;
  gboolean   update_col_info = TRUE;
  gboolean   save_fragmented;
  ws_ip *iph;
  const guchar		*src_addr, *dst_addr;
  guint32 		src32, dst32;
  proto_tree *tree;
  proto_item *item=NULL, *ttl_item;
  proto_tree *checksum_tree;
  guint16 ttl;

  tree=parent_tree;

  iph=ep_alloc(sizeof(ws_ip));

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPv4");
  col_clear(pinfo->cinfo, COL_INFO);

  iph->ip_v_hl = tvb_get_guint8(tvb, offset);
  if ( hi_nibble(iph->ip_v_hl) == 6){
	  call_dissector(ipv6_handle, tvb, pinfo, parent_tree);
	  return;
  }

  hlen = lo_nibble(iph->ip_v_hl) * 4;	/* IP header length, in bytes */

  if (tree) {
    ti = proto_tree_add_item(tree, proto_ip, tvb, offset, hlen, FALSE);
    ip_tree = proto_item_add_subtree(ti, ett_ip);

    proto_tree_add_uint(ip_tree, hf_ip_version, tvb, offset, 1,
	hi_nibble(iph->ip_v_hl));
  }

  /* if IP is not referenced from any filters we dont need to worry about
     generating any tree items.  We must do this after we created the actual
     protocol above so that proto hier stat still works though.
     XXX: Note that because of the following optimization expert items must 
          not be generated inside of an 'if (tree) ...' 
          so that Analyze ! Expert ...  will work.
  */
  if(!proto_field_is_referenced(parent_tree, proto_ip)){
    tree=NULL;
  }

  if (hlen < IPH_MIN_LEN) {
    col_add_fstr(pinfo->cinfo, COL_INFO, "Bogus IP header length (%u, must be at least %u)",
       hlen, IPH_MIN_LEN);
    if (tree) {
      proto_tree_add_uint_format(ip_tree, hf_ip_hdr_len, tvb, offset, 1, hlen,
	"Header length: %u bytes (bogus, must be at least %u)", hlen,
	IPH_MIN_LEN);
    }
    return;
  }

  if (tree) {
	proto_tree_add_uint_format(ip_tree, hf_ip_hdr_len, tvb, offset, 1, hlen,
	"Header length: %u bytes", hlen);
  }

  iph->ip_tos = tvb_get_guint8(tvb, offset + 1);
  if (g_ip_dscp_actif) {
    col_add_fstr(pinfo->cinfo, COL_DSCP_VALUE, "%u", IPDSFIELD_DSCP(iph->ip_tos));
  }

  if (tree) {
    if (g_ip_dscp_actif) {
      tf = proto_tree_add_uint_format(ip_tree, hf_ip_dsfield, tvb, offset + 1, 1, iph->ip_tos,
	   "Differentiated Services Field: 0x%02x (DSCP 0x%02x: %s; ECN: 0x%02x: %s)", iph->ip_tos,
	   IPDSFIELD_DSCP(iph->ip_tos), val_to_str(IPDSFIELD_DSCP(iph->ip_tos), dscp_vals, "Unknown DSCP"),
	   IPDSFIELD_ECN(iph->ip_tos), val_to_str(IPDSFIELD_ECN(iph->ip_tos), ecn_vals, "Unknown ECN"));

      field_tree = proto_item_add_subtree(tf, ett_ip_dsfield);
      proto_tree_add_item(field_tree, hf_ip_dsfield_dscp, tvb, offset + 1, 1, ENC_NA);
      proto_tree_add_item(field_tree, hf_ip_dsfield_ecn, tvb, offset + 1, 1, ENC_NA);
    } else {
      tf = proto_tree_add_uint_format(ip_tree, hf_ip_tos, tvb, offset + 1, 1, iph->ip_tos,
	  "Type of service: 0x%02x (%s)", iph->ip_tos,
	  val_to_str( IPTOS_TOS(iph->ip_tos), iptos_vals, "Unknown") );

      field_tree = proto_item_add_subtree(tf, ett_ip_tos);
      proto_tree_add_item(field_tree, hf_ip_tos_precedence, tvb, offset + 1, 1, ENC_NA);
      proto_tree_add_item(field_tree, hf_ip_tos_delay, tvb, offset + 1, 1, ENC_NA);
      proto_tree_add_item(field_tree, hf_ip_tos_throughput, tvb, offset + 1, 1, ENC_NA);
      proto_tree_add_item(field_tree, hf_ip_tos_reliability, tvb, offset + 1, 1, ENC_NA);
      proto_tree_add_item(field_tree, hf_ip_tos_cost, tvb, offset + 1, 1, ENC_NA);
    }
  }

  /* Length of IP datagram.
     XXX - what if this is greater than the reported length of the
     tvbuff?  This could happen, for example, in an IP datagram
     inside an ICMP datagram; we need to somehow let the
     dissector we call know that, as it might want to avoid
     doing its checksumming. */
  iph->ip_len = tvb_get_ntohs(tvb, offset + 2);

  /* Correct for zero-length TSO packets
   * If ip_len is zero, assume TSO and use the reported length instead.  Note
   * that we need to use the frame/reported length instead of the
   * actually-available length, just in case a snaplen was used on capture. */
  if (ip_tso_supported && !iph->ip_len)
	  iph->ip_len = tvb_reported_length(tvb);

  if (iph->ip_len < hlen) {
    col_add_fstr(pinfo->cinfo, COL_INFO, "Bogus IP length (%u, less than header length %u)",
       iph->ip_len, hlen);
    if (tree) {
      if (!iph->ip_len) {
        tf = proto_tree_add_uint_format(ip_tree, hf_ip_len, tvb, offset + 2, 2, iph->ip_len,
         "Total length: 0 bytes (maybe caused by \"TCP segmentation offload\" (TSO)?)");
      } else {
        tf = proto_tree_add_uint_format(ip_tree, hf_ip_len, tvb, offset + 2, 2, iph->ip_len,
         "Total length: %u bytes (bogus, less than header length %u)", iph->ip_len,
         hlen);
      }
      expert_add_info_format(pinfo, tf, PI_PROTOCOL, PI_ERROR, "Bogus IP length");
    }
    return;
  }

  /*
   * Now that we know that the total length of this IP datagram isn't
   * obviously bogus, adjust the length of this tvbuff to include only
   * the IP datagram.
   */
  set_actual_length(tvb, iph->ip_len);

  if (tree)
	proto_tree_add_uint(ip_tree, hf_ip_len, tvb, offset + 2, 2, iph->ip_len);

  iph->ip_id  = tvb_get_ntohs(tvb, offset + 4);
  if (tree)
	proto_tree_add_uint(ip_tree, hf_ip_id, tvb, offset + 4, 2, iph->ip_id);

  iph->ip_off = tvb_get_ntohs(tvb, offset + 6);
  if (tree) {
    int bit_offset = (offset + 6) * 8;
    flags = (iph->ip_off & (IP_RF | IP_DF | IP_MF)) >> IP_OFFSET_WIDTH;
    tf = proto_tree_add_uint(ip_tree, hf_ip_flags, tvb, offset + 6, 1, flags);
    field_tree = proto_item_add_subtree(tf, ett_ip_off);
    if (ip_security_flag) {
      proto_item *sf;
      sf = proto_tree_add_bits_item(field_tree, hf_ip_flags_sf, tvb, bit_offset + 0, 1, FALSE);
      if (iph->ip_off & IP_RF) {
        proto_item_append_text(tf, " (Evil packet!)");
        expert_add_info_format(pinfo, sf, PI_SECURITY, PI_WARN, "This is an Evil packet (RFC 3514)");
      }
    } else {
      proto_tree_add_bits_item(field_tree, hf_ip_flags_rf, tvb, bit_offset + 0, 1, TRUE);
    }
    if (iph->ip_off & IP_DF) proto_item_append_text(tf, " (Don't Fragment)");
    proto_tree_add_bits_item(field_tree, hf_ip_flags_df, tvb, bit_offset + 1, 1, FALSE);
    if (iph->ip_off & IP_MF) proto_item_append_text(tf, " (More Fragments)");
    proto_tree_add_bits_item(field_tree, hf_ip_flags_mf, tvb, bit_offset + 2, 1, FALSE);

    proto_tree_add_uint(ip_tree, hf_ip_frag_offset, tvb, offset + 6, 2,
      (iph->ip_off & IP_OFFSET)*8);
  }

  iph->ip_ttl = tvb_get_guint8(tvb, offset + 8);
  pinfo->ip_ttl = iph->ip_ttl;
  if (tree) {
    ttl_item = proto_tree_add_item(ip_tree, hf_ip_ttl, tvb, offset + 8, 1, FALSE);
  } else {
    ttl_item = NULL;
  }

  iph->ip_p = tvb_get_guint8(tvb, offset + 9);
  if (tree) {
    proto_tree_add_item(ip_tree, hf_ip_proto, tvb, offset + 9, 1, FALSE);
  }

  iph->ip_sum = tvb_get_ntohs(tvb, offset + 10);

  /*
   * If we have the entire IP header available, check the checksum.
   */
  if (ip_check_checksum && tvb_bytes_exist(tvb, offset, hlen)) {
    ipsum = ip_checksum(tvb_get_ptr(tvb, offset, hlen), hlen);
    if (tree) {
      if (ipsum == 0) {
        item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
                                          "Header checksum: 0x%04x [correct]", iph->ip_sum);
        checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
        item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, TRUE);
        PROTO_ITEM_SET_GENERATED(item);
        item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, FALSE);
        PROTO_ITEM_SET_GENERATED(item);
      } else {
        item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
                                          "Header checksum: 0x%04x [incorrect, should be 0x%04x (maybe caused by \"IP checksum offload\"?)]", iph->ip_sum,
        in_cksum_shouldbe(iph->ip_sum, ipsum));
        checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
        item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, FALSE);
        PROTO_ITEM_SET_GENERATED(item);
        item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, TRUE);
        PROTO_ITEM_SET_GENERATED(item);
      }
    }
    if (ipsum != 0) /* Add expert item always (so tap gets called if present);
                       if (tree==NULL) then item will be NULL
                       else item should be from the add_boolean(..., hf_ip_checksum_bad, ...) above */
      expert_add_info_format(pinfo, item, PI_CHECKSUM, PI_ERROR, "Bad checksum");
  } else { 
    ipsum = 0;
    if (tree) {
      item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
                                        "Header checksum: 0x%04x [%s]", iph->ip_sum,
                                        ip_check_checksum ? "not all data available" : "validation disabled");
      checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
      item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, FALSE);
      PROTO_ITEM_SET_GENERATED(item);
      item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, FALSE);
      PROTO_ITEM_SET_GENERATED(item);
    }
  }
  src_addr = tvb_get_ptr(tvb, offset + IPH_SRC, 4);
  src32 = tvb_get_ntohl(tvb, offset + IPH_SRC);
  SET_ADDRESS(&pinfo->net_src, AT_IPv4, 4, src_addr);
  SET_ADDRESS(&pinfo->src, AT_IPv4, 4, src_addr);
  SET_ADDRESS(&iph->ip_src, AT_IPv4, 4, src_addr);
  if (tree) {
    const char *src_host;

    memcpy(&addr, iph->ip_src.data, 4);
    src_host = get_hostname(addr);
    if (ip_summary_in_tree) {
      proto_item_append_text(ti, ", Src: %s (%s)", src_host, ip_to_str(iph->ip_src.data));
    }
    proto_tree_add_ipv4(ip_tree, hf_ip_src, tvb, offset + 12, 4, addr);
    item = proto_tree_add_ipv4(ip_tree, hf_ip_addr, tvb, offset + 12, 4, addr);
    PROTO_ITEM_SET_HIDDEN(item);
    item = proto_tree_add_string(ip_tree, hf_ip_src_host, tvb, offset + 12, 4, src_host);
    PROTO_ITEM_SET_GENERATED(item);
    PROTO_ITEM_SET_HIDDEN(item);
    item = proto_tree_add_string(ip_tree, hf_ip_host, tvb, offset + 12, 4, src_host);
    PROTO_ITEM_SET_GENERATED(item);
    PROTO_ITEM_SET_HIDDEN(item);
  }
  dst_addr = tvb_get_ptr(tvb, offset + IPH_DST, 4);
  dst32 = tvb_get_ntohl(tvb, offset + IPH_DST);
  SET_ADDRESS(&pinfo->net_dst, AT_IPv4, 4, dst_addr);
  SET_ADDRESS(&pinfo->dst, AT_IPv4, 4, dst_addr);
  SET_ADDRESS(&iph->ip_dst, AT_IPv4, 4, dst_addr);

  tap_queue_packet(ip_tap, pinfo, iph);


  /* If an IP is destined for an IP address in the Local Network Control Block
   * (e.g. 224.0.0.0/24), the packet should never be routed and the TTL would
   * be expected to be 1.  (see RFC 3171)  Flag a TTL greater than 1.
   *
   * Flag a low TTL if the packet is not destined for a multicast address
   * (e.g. 224.0.0.0/4) ... and the payload isn't protocol 103 (PIM).
   * (see http://tools.ietf.org/html/rfc3973#section-4.7).
   */
  if (is_a_local_network_control_block_addr(dst32)) {
    ttl = local_network_control_block_addr_valid_ttl(dst32);
    if (ttl != iph->ip_ttl && ttl != IPLOCAL_NETWRK_CTRL_BLK_ANY_TTL) {
      expert_add_info_format(pinfo, ttl_item, PI_SEQUENCE, PI_NOTE,
        "\"Time To Live\" != %d for a packet sent to the Local Network Control Block (see RFC 3171)", ttl);
    }
  } else if (!is_a_multicast_addr(dst32) && iph->ip_ttl < 5 && (iph->ip_p != IP_PROTO_PIM)) {
    expert_add_info_format(pinfo, ttl_item, PI_SEQUENCE, PI_NOTE, "\"Time To Live\" only %u", iph->ip_ttl);
  }

  if (tree) {
    const char *dst_host;

    memcpy(&addr, iph->ip_dst.data, 4);
    dst_host = get_hostname(addr);
    if (ip_summary_in_tree) {
      proto_item_append_text(ti, ", Dst: %s (%s)", dst_host, ip_to_str(iph->ip_dst.data));
    }
    proto_tree_add_ipv4(ip_tree, hf_ip_dst, tvb, offset + 16, 4, addr);
    item = proto_tree_add_ipv4(ip_tree, hf_ip_addr, tvb, offset + 16, 4, addr);
    PROTO_ITEM_SET_HIDDEN(item);
    item = proto_tree_add_string(ip_tree, hf_ip_dst_host, tvb, offset + 16, 4, dst_host);
    PROTO_ITEM_SET_GENERATED(item);
    PROTO_ITEM_SET_HIDDEN(item);
    item = proto_tree_add_string(ip_tree, hf_ip_host, tvb, offset + 16, 4, dst_host);
    PROTO_ITEM_SET_GENERATED(item);
    PROTO_ITEM_SET_HIDDEN(item);
  }

#ifdef HAVE_GEOIP
  if (tree && ip_use_geoip) {
    add_geoip_info(ip_tree, tvb, offset, src32, dst32);
  }
#endif

  if (tree) {
    /* Decode IP options, if any. */
    if (hlen > IPH_MIN_LEN) {
      /* There's more than just the fixed-length header.  Decode the
         options. */
      optlen = hlen - IPH_MIN_LEN;	/* length of options, in bytes */
      tf = proto_tree_add_text(ip_tree, tvb, offset + 20, optlen,
        "Options: (%u bytes)", optlen);
      field_tree = proto_item_add_subtree(tf, ett_ip_options);
      dissect_ip_tcp_options(tvb, offset + 20, optlen,
         ipopts, N_IP_OPTS, IPOPT_END, pinfo, field_tree, tf);
    }
  }

  pinfo->ipproto = iph->ip_p;

  pinfo->iplen = iph->ip_len;

  pinfo->iphdrlen = hlen;

  /* Skip over header + options */
  offset += hlen;
  nxt = iph->ip_p;	/* XXX - what if this isn't the same for all fragments? */

  /* If ip_defragment is on, this is a fragment, we have all the data
   * in the fragment, and the header checksum is valid, then just add
   * the fragment to the hashtable.
   */
  save_fragmented = pinfo->fragmented;
  if (ip_defragment && (iph->ip_off & (IP_MF|IP_OFFSET)) &&
      tvb_bytes_exist(tvb, offset, pinfo->iplen - pinfo->iphdrlen) &&
      ipsum == 0) {
    ipfd_head = fragment_add_check(tvb, offset, pinfo,
                                   iph->ip_p ^ iph->ip_id ^ src32 ^ dst32,
                                   ip_fragment_table,
                                   ip_reassembled_table,
                                   (iph->ip_off & IP_OFFSET)*8,
                                   pinfo->iplen - pinfo->iphdrlen,
                                   iph->ip_off & IP_MF);

    next_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled IPv4",
    ipfd_head, &ip_frag_items, &update_col_info, ip_tree);
  } else {
    /* If this is the first fragment, dissect its contents, otherwise
       just show it as a fragment.

       XXX - if we eventually don't save the reassembled contents of all
       fragmented datagrams, we may want to always reassemble. */
    if (iph->ip_off & IP_OFFSET) {
      /* Not the first fragment - don't dissect it. */
      next_tvb = NULL;
    } else {
      /* First fragment, or not fragmented.  Dissect what we have here. */

      /* Get a tvbuff for the payload. */
      next_tvb = tvb_new_subset_remaining(tvb, offset);

      /*
       * If this is the first fragment, but not the only fragment,
       * tell the next protocol that.
       */
      if (iph->ip_off & IP_MF)
        pinfo->fragmented = TRUE;
      else
        pinfo->fragmented = FALSE;
    }
  }

  if (next_tvb == NULL) {
    /* Just show this as a fragment. */
    col_add_fstr(pinfo->cinfo, COL_INFO, "Fragmented IP protocol (proto=%s 0x%02x, off=%u, ID=%04x)",
		ipprotostr(iph->ip_p), iph->ip_p, (iph->ip_off & IP_OFFSET) * 8,
		iph->ip_id);
    if( ipfd_head && ipfd_head->reassembled_in != pinfo->fd->num ){
      col_append_fstr(pinfo->cinfo, COL_INFO, " [Reassembled in #%u]",
          ipfd_head->reassembled_in);
    }

    call_dissector(data_handle, tvb_new_subset_remaining(tvb, offset), pinfo,
                   parent_tree);
    pinfo->fragmented = save_fragmented;
    return;
  }

  /* XXX This is an ugly hack because I didn't manage to make the IPIP
   * dissector a heuristic one [JMayer]
   * The TAPA protocol also uses IP protocol number 4 but it isn't really
   * IPIP, so try to detect it first and call it explicitly before calling
   * the generic ip.proto dispatcher
   */
  if (nxt == IP_PROTO_IPIP &&
        (tvb_get_guint8(next_tvb, 0) & 0xF0) != 0x40 &&
        tvb_get_ntohs(next_tvb, 2) < 20) {
     call_dissector(tapa_handle,next_tvb, pinfo, parent_tree);

  /* Hand off to the next protocol.

     XXX - setting the columns only after trying various dissectors means
     that if one of those dissectors throws an exception, the frame won't
     even be labelled as an IP frame; ideally, if a frame being dissected
     throws an exception, it'll be labelled as a mangled frame of the
     type in question. */
  } else if (!dissector_try_uint(ip_dissector_table, nxt, next_tvb, pinfo, parent_tree)) {
    /* Unknown protocol */
    if (update_col_info) {
      col_add_fstr(pinfo->cinfo, COL_INFO, "%s (0x%02x)", ipprotostr(iph->ip_p), iph->ip_p);
    }
    call_dissector(data_handle,next_tvb, pinfo, parent_tree);
  }
  pinfo->fragmented = save_fragmented;
}

void
proto_register_ip(void)
{
#define ARG_TO_STR(ARG) #ARG
#define FLAGS_OFFSET_WIDTH_MSG(WIDTH) \
    "Flags (" ARG_TO_STR(WIDTH) " bits)"
#define FRAG_OFFSET_WIDTH_MSG(WIDTH) \
    "Fragment offset (" ARG_TO_STR(WIDTH) " bits)"

	static hf_register_info hf[] = {

		{ &hf_ip_version,
		{ "Version",		"ip.version", FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_hdr_len,
		{ "Header Length",	"ip.hdr_len", FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_dsfield,
		{ "Differentiated Services field",	"ip.dsfield", FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_dsfield_dscp,
		{ "Differentiated Services Codepoint",	"ip.dsfield.dscp", FT_UINT8, BASE_HEX,
			VALS(dscp_vals), IPDSFIELD_DSCP_MASK,
			NULL, HFILL }},

		{ &hf_ip_dsfield_ecn,
		{ "Explicit Congestion Notification",	"ip.dsfield.ecn", FT_UINT8, BASE_HEX,
			VALS(ecn_vals),	IPDSFIELD_ECN_MASK,
			NULL, HFILL }},

		{ &hf_ip_tos,
		{ "Type of Service",	"ip.tos", FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_tos_precedence,
		{ "Precedence",		"ip.tos.precedence", FT_UINT8, BASE_DEC, VALS(precedence_vals),
			IPTOS_PREC_MASK,
			NULL, HFILL }},

		{ &hf_ip_tos_delay,
		{ "Delay",		"ip.tos.delay", FT_BOOLEAN, 8, TFS(&tos_set_low),
			IPTOS_LOWDELAY,
			NULL, HFILL }},

		{ &hf_ip_tos_throughput,
		{ "Throughput",		"ip.tos.throughput", FT_BOOLEAN, 8, TFS(&tos_set_high),
			IPTOS_THROUGHPUT,
			NULL, HFILL }},

		{ &hf_ip_tos_reliability,
		{ "Reliability",	"ip.tos.reliability", FT_BOOLEAN, 8, TFS(&tos_set_high),
			IPTOS_RELIABILITY,
			NULL, HFILL }},

		{ &hf_ip_tos_cost,
		{ "Cost",		"ip.tos.cost", FT_BOOLEAN, 8, TFS(&tos_set_low),
			IPTOS_LOWCOST,
			NULL, HFILL }},

		{ &hf_ip_len,
		{ "Total Length",	"ip.len", FT_UINT16, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_id,
		{ "Identification",	"ip.id", FT_UINT16, BASE_HEX_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_dst,
		{ "Destination",	"ip.dst", FT_IPv4, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_dst_host,
		{ "Destination Host",		"ip.dst_host", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_src,
		{ "Source",		"ip.src", FT_IPv4, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_src_host,
		{ "Source Host",		"ip.src_host", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_addr,
		{ "Source or Destination Address", "ip.addr", FT_IPv4, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_host,
		{ "Source or Destination Host", "ip.host", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
#ifdef HAVE_GEOIP
		{ &hf_geoip_country,
		{ "Source or Destination GeoIP Country", "ip.geoip.country", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_city,
		{ "Source or Destination GeoIP City", "ip.geoip.city", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_org,
		{ "Source or Destination GeoIP Organization", "ip.geoip.org", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_isp,
		{ "Source or Destination GeoIP ISP", "ip.geoip.isp", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_asnum,
		{ "Source or Destination GeoIP AS Number", "ip.geoip.asnum", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_lat,
		{ "Source or Destination GeoIP Latitude", "ip.geoip.lat", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_lon,
		{ "Source or Destination GeoIP Longitude", "ip.geoip.lon", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_country,
		{ "Source GeoIP Country", "ip.geoip.src_country", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_city,
		{ "Source GeoIP City", "ip.geoip.src_city", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_org,
		{ "Source GeoIP Organization", "ip.geoip.src_org", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_isp,
		{ "Source GeoIP ISP", "ip.geoip.src_isp", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_asnum,
		{ "Source GeoIP AS Number", "ip.geoip.src_asnum", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_lat,
		{ "Source GeoIP Latitude", "ip.geoip.src_lat", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_src_lon,
		{ "Source GeoIP Longitude", "ip.geoip.src_lon", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_country,
		{ "Destination GeoIP Country", "ip.geoip.dst_country", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_city,
		{ "Destination GeoIP City", "ip.geoip.dst_city", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_org,
		{ "Destination GeoIP Organization", "ip.geoip.dst_org", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_isp,
		{ "Destination GeoIP ISP", "ip.geoip.dst_isp", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_asnum,
		{ "Destination GeoIP AS Number", "ip.geoip.dst_asnum", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_lat,
		{ "Destination GeoIP Latitude", "ip.geoip.dst_lat", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
		{ &hf_geoip_dst_lon,
		{ "Destination GeoIP Longitude", "ip.geoip.dst_lon", FT_STRING, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},
#endif /* HAVE_GEOIP */
		{ &hf_ip_flags,
		{ "Flags",		"ip.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
			FLAGS_OFFSET_WIDTH_MSG(IP_FLAGS_WIDTH), HFILL }},

		{ &hf_ip_flags_sf,
		{ "Security flag", "ip.flags.sf", FT_BOOLEAN, IP_FLAGS_WIDTH, TFS(&flags_sf_set_evil), 0x0,
			"Security flag (RFC 3514)", HFILL }},

		{ &hf_ip_flags_rf,
		{ "Reserved bit", "ip.flags.rb", FT_BOOLEAN, IP_FLAGS_WIDTH, TFS(&tfs_set_notset), 0x0,
			NULL, HFILL }},

		{ &hf_ip_flags_df,
		{ "Don't fragment", "ip.flags.df", FT_BOOLEAN, IP_FLAGS_WIDTH, TFS(&tfs_set_notset), 0x0,
			NULL, HFILL }},

		{ &hf_ip_flags_mf,
		{ "More fragments", "ip.flags.mf", FT_BOOLEAN, IP_FLAGS_WIDTH, TFS(&tfs_set_notset), 0x0,
			NULL, HFILL }},

		{ &hf_ip_frag_offset,
		{ "Fragment offset",	"ip.frag_offset", FT_UINT16, BASE_DEC, NULL, 0x0,
			FRAG_OFFSET_WIDTH_MSG(IP_OFFSET_WIDTH), HFILL }},

		{ &hf_ip_ttl,
		{ "Time to live",	"ip.ttl", FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_proto,
		{ "Protocol",		"ip.proto", FT_UINT8, BASE_DEC|BASE_EXT_STRING, (&ipproto_val_ext), 0x0,
			NULL, HFILL }},

		{ &hf_ip_checksum,
		{ "Header checksum",	"ip.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_checksum_good,
		{ "Good",	"ip.checksum_good", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
			"True: checksum matches packet content; False: doesn't match content or not checked", HFILL }},

		{ &hf_ip_checksum_bad,
		{ "Bad",	"ip.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
			"True: checksum doesn't match packet content; False: matches content or not checked", HFILL }},

		{ &hf_ip_fragment_overlap,
		{ "Fragment overlap",	"ip.fragment.overlap", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
			"Fragment overlaps with other fragments", HFILL }},

		{ &hf_ip_fragment_overlap_conflict,
		{ "Conflicting data in fragment overlap",	"ip.fragment.overlap.conflict", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
			"Overlapping fragments contained conflicting data", HFILL }},

		{ &hf_ip_fragment_multiple_tails,
		{ "Multiple tail fragments found",	"ip.fragment.multipletails", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
			"Several tails were found when defragmenting the packet", HFILL }},

		{ &hf_ip_fragment_too_long_fragment,
		{ "Fragment too long",	"ip.fragment.toolongfragment", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
			"Fragment contained data past end of packet", HFILL }},

		{ &hf_ip_fragment_error,
		{ "Defragmentation error", "ip.fragment.error", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
			"Defragmentation error due to illegal fragments", HFILL }},

		{ &hf_ip_fragment_count,
		{ "Fragment count", "ip.fragment.count", FT_UINT32, BASE_DEC, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_fragment,
		{ "IPv4 Fragment", "ip.fragment", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_fragments,
		{ "IPv4 Fragments", "ip.fragments", FT_BYTES, BASE_NONE, NULL, 0x0,
			NULL, HFILL }},

		{ &hf_ip_reassembled_in,
		{ "Reassembled IPv4 in frame", "ip.reassembled_in", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
		  "This IPv4 packet is reassembled in this frame", HFILL }},

		{ &hf_ip_reassembled_length,
		{ "Reassembled IPv4 length", "ip.reassembled.length", FT_UINT32, BASE_DEC, NULL, 0x0,
			"The total length of the reassembled payload", HFILL }}
	};
	static gint *ett[] = {
		&ett_ip,
		&ett_ip_dsfield,
		&ett_ip_tos,
		&ett_ip_off,
		&ett_ip_options,
		&ett_ip_option_sec,
		&ett_ip_option_route,
		&ett_ip_option_timestamp,
		&ett_ip_option_cipso,
		&ett_ip_fragments,
		&ett_ip_fragment,
		&ett_ip_checksum,
#ifdef HAVE_GEOIP
		&ett_geoip_info
#endif
	};
	module_t *ip_module;

	proto_ip = proto_register_protocol("Internet Protocol Version 4", "IPv4", "ip");
	proto_register_field_array(proto_ip, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));

	/* subdissector code */
	ip_dissector_table = register_dissector_table("ip.proto",
	    "IPv4 protocol", FT_UINT8, BASE_DEC);

	/* Register configuration options */
	ip_module = prefs_register_protocol(proto_ip, NULL);
	prefs_register_bool_preference(ip_module, "decode_tos_as_diffserv",
	    "Decode IPv4 TOS field as DiffServ field",
	    "Whether the IPv4 type-of-service field should be decoded as a Differentiated Services field (see RFC2474/RFC2475)",
	    &g_ip_dscp_actif);
	prefs_register_bool_preference(ip_module, "defragment",
		"Reassemble fragmented IPv4 datagrams",
		"Whether fragmented IPv4 datagrams should be reassembled",
		&ip_defragment);
	prefs_register_bool_preference(ip_module, "summary_in_tree",
	    "Show IPv4 summary in protocol tree",
	    "Whether the IPv4 summary line should be shown in the protocol tree",
	    &ip_summary_in_tree);
	prefs_register_bool_preference(ip_module, "check_checksum" ,
		  "Validate the IPv4 checksum if possible",
		  "Whether to validate the IPv4 checksum",
		  &ip_check_checksum);
	prefs_register_bool_preference(ip_module, "tso_support" ,
		  "Support packet-capture from IP TSO-enabled hardware",
		  "Whether to correct for TSO-enabled (TCP segmentation offload) hardware captures, such as spoofing the IP packet length",
		  &ip_tso_supported);
#ifdef HAVE_GEOIP
	prefs_register_bool_preference(ip_module, "use_geoip" ,
		  "Enable GeoIP lookups",
		  "Whether to look up IP addresses in each GeoIP database we have loaded",
		  &ip_use_geoip);
#endif /* HAVE_GEOIP */
	prefs_register_bool_preference(ip_module, "security_flag" ,
		  "Interpret Reserved flag as Security flag (RFC 3514)",
		  "Whether to interpret the originally reserved flag as security flag",
		  &ip_security_flag);

	register_dissector("ip", dissect_ip, proto_ip);
	register_init_routine(ip_defragment_init);
        ip_tap=register_tap("ip");
}

void
proto_reg_handoff_ip(void)
{
	dissector_handle_t ip_handle;

        ip_handle = find_dissector("ip");
	ipv6_handle = find_dissector("ipv6");
	tapa_handle = find_dissector("tapa");
        data_handle = find_dissector("data");

	dissector_add_uint("ethertype", ETHERTYPE_IP, ip_handle);
	dissector_add_uint("ppp.protocol", PPP_IP, ip_handle);
	dissector_add_uint("ppp.protocol", ETHERTYPE_IP, ip_handle);
	dissector_add_uint("gre.proto", ETHERTYPE_IP, ip_handle);
	dissector_add_uint("gre.proto", GRE_WCCP, ip_handle);
	dissector_add_uint("llc.dsap", SAP_IP, ip_handle);
	dissector_add_uint("ip.proto", IP_PROTO_IPIP, ip_handle);
	dissector_add_uint("null.type", BSD_AF_INET, ip_handle);
	dissector_add_uint("chdlctype", ETHERTYPE_IP, ip_handle);
	dissector_add_uint("osinl.excl", NLPID_IP, ip_handle);
	dissector_add_uint("fr.ietf", NLPID_IP, ip_handle);
	dissector_add_uint("x.25.spi", NLPID_IP, ip_handle);
	dissector_add_uint("arcnet.protocol_id", ARCNET_PROTO_IP_1051, ip_handle);
	dissector_add_uint("arcnet.protocol_id", ARCNET_PROTO_IP_1201, ip_handle);
	dissector_add_handle("udp.port", ip_handle);
}
