text: /*	$NetBSD: pcap-common.c,v 1.4 2015/08/28 11:20:55 joerg Exp $	*/
  
  /*
   * Copyright (c) 1993, 1994, 1995, 1996, 1997
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that: (1) source code distributions
   * retain the above copyright notice and this paragraph in its entirety, (2)
   * distributions including binary code include the above copyright notice and
   * this paragraph in its entirety in the documentation or other materials
   * provided with the distribution, and (3) all advertising materials mentioning
   * features or use of this software display the following acknowledgement:
   * ``This product includes software developed by the University of California,
   * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
   * the University nor the names of its contributors may be used to endorse
   * or promote products derived from this software without specific prior
   * written permission.
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   *
   * pcap-common.c - common code for pcap and pcap-ng files
   */
  
  #include <sys/cdefs.h>
  __RCSID("$NetBSD: pcap-common.c,v 1.4 2015/08/28 11:20:55 joerg Exp $");
  
  #ifdef HAVE_CONFIG_H
  #include "config.h"
  #endif
  
  #ifdef WIN32
  #include <pcap-stdinc.h>
  #else /* WIN32 */
  #if HAVE_INTTYPES_H
  #include <inttypes.h>
  #elif HAVE_STDINT_H
  #include <stdint.h>
  #endif
  #ifdef HAVE_SYS_BITYPES_H
  #include <sys/bitypes.h>
  #endif
  #include <sys/types.h>
  #endif /* WIN32 */
  
  #include "pcap-int.h"
  #include "pcap/usb.h"
  #include "pcap/nflog.h"
  
  #include "pcap-common.h"
  
  /*
   * We don't write DLT_* values to capture files, because they're not the
   * same on all platforms.
   *
   * Unfortunately, the various flavors of BSD have not always used the same
   * numerical values for the same data types, and various patches to
   * libpcap for non-BSD OSes have added their own DLT_* codes for link
   * layer encapsulation types seen on those OSes, and those codes have had,
   * in some cases, values that were also used, on other platforms, for other
   * link layer encapsulation types.
   *
   * This means that capture files of a type whose numerical DLT_* code
   * means different things on different BSDs, or with different versions
   * of libpcap, can't always be read on systems other than those like
   * the one running on the machine on which the capture was made.
   *
   * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
   * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
   * codes to DLT_* codes when reading a savefile header.
   *
   * For those DLT_* codes that have, as far as we know, the same values on
   * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
   * DLT_xxx; that way, captures of those types can still be read by
   * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
   * captures of those types written by versions of libpcap that map DLT_
   * values to LINKTYPE_ values can still be read by older versions
   * of libpcap.
   *
   * The other LINKTYPE_* codes are given values starting at 100, in the
   * hopes that no DLT_* code will be given one of those values.
   *
   * In order to ensure that a given LINKTYPE_* code's value will refer to
   * the same encapsulation type on all platforms, you should not allocate
   * a new LINKTYPE_* value without consulting
   * "tcpdump-workers@lists.tcpdump.org".  The tcpdump developers will
   * allocate a value for you, and will not subsequently allocate it to
   * anybody else; that value will be added to the "pcap.h" in the
   * tcpdump.org Git repository, so that a future libpcap release will
   * include it.
   *
   * You should, if possible, also contribute patches to libpcap and tcpdump
   * to handle the new encapsulation type, so that they can also be checked
   * into the tcpdump.org Git repository and so that they will appear in
   * future libpcap and tcpdump releases.
   *
   * Do *NOT* assume that any values after the largest value in this file
   * are available; you might not have the most up-to-date version of this
   * file, and new values after that one might have been assigned.  Also,
   * do *NOT* use any values below 100 - those might already have been
   * taken by one (or more!) organizations.
   *
   * Any platform that defines additional DLT_* codes should:
   *
   *	request a LINKTYPE_* code and value from tcpdump.org,
   *	as per the above;
   *
   *	add, in their version of libpcap, an entry to map
   *	those DLT_* codes to the corresponding LINKTYPE_*
   *	code;
   *
   *	redefine, in their "net/bpf.h", any DLT_* values
   *	that collide with the values used by their additional
   *	DLT_* codes, to remove those collisions (but without
   *	making them collide with any of the LINKTYPE_*
   *	values equal to 50 or above; they should also avoid
   *	defining DLT_* values that collide with those
   *	LINKTYPE_* values, either).
   */
  #define LINKTYPE_NULL		DLT_NULL
  #define LINKTYPE_ETHERNET	DLT_EN10MB	/* also for 100Mb and up */
  #define LINKTYPE_EXP_ETHERNET	DLT_EN3MB	/* 3Mb experimental Ethernet */
  #define LINKTYPE_AX25		DLT_AX25
  #define LINKTYPE_PRONET		DLT_PRONET
  #define LINKTYPE_CHAOS		DLT_CHAOS
  #define LINKTYPE_IEEE802_5	DLT_IEEE802	/* DLT_IEEE802 is used for 802.5 Token Ring */
  #define LINKTYPE_ARCNET_BSD	DLT_ARCNET	/* BSD-style headers */
  #define LINKTYPE_SLIP		DLT_SLIP
  #define LINKTYPE_PPP		DLT_PPP
  #define LINKTYPE_FDDI		DLT_FDDI
  
  /*
   * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
   * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
   * field) at the beginning of the packet.
   *
   * This is for use when there is always such a header; the address field
   * might be 0xff, for regular PPP, or it might be an address field for Cisco
   * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
   * HDLC").  This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
   *
   * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
   * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
   * captures will be written out with a link type that NetBSD's tcpdump
   * can read.
   */
  #define LINKTYPE_PPP_HDLC	50		/* PPP in HDLC-like framing */
  
  #define LINKTYPE_PPP_ETHER	51		/* NetBSD PPP-over-Ethernet */
  
  #define LINKTYPE_SYMANTEC_FIREWALL 99		/* Symantec Enterprise Firewall */
  
  /*
   * These correspond to DLT_s that have different values on different
   * platforms; we map between these values in capture files and
   * the DLT_ values as returned by pcap_datalink() and passed to
   * pcap_open_dead().
   */
  #define LINKTYPE_ATM_RFC1483	100		/* LLC/SNAP-encapsulated ATM */
  #define LINKTYPE_RAW		101		/* raw IP */
  #define LINKTYPE_SLIP_BSDOS	102		/* BSD/OS SLIP BPF header */
  #define LINKTYPE_PPP_BSDOS	103		/* BSD/OS PPP BPF header */
  
  /*
   * Values starting with 104 are used for newly-assigned link-layer
   * header type values; for those link-layer header types, the DLT_
   * value returned by pcap_datalink() and passed to pcap_open_dead(),
   * and the LINKTYPE_ value that appears in capture files, are the
   * same.
   *
   * LINKTYPE_MATCHING_MIN is the lowest such value; LINKTYPE_MATCHING_MAX
   * is the highest such value.
   */
  #define LINKTYPE_MATCHING_MIN	104		/* lowest value in the "matching" range */
  
  #define LINKTYPE_C_HDLC		104		/* Cisco HDLC */
  #define LINKTYPE_IEEE802_11	105		/* IEEE 802.11 (wireless) */
  #define LINKTYPE_ATM_CLIP	106		/* Linux Classical IP over ATM */
  #define LINKTYPE_FRELAY		107		/* Frame Relay */
  #define LINKTYPE_LOOP		108		/* OpenBSD loopback */
  #define LINKTYPE_ENC		109		/* OpenBSD IPSEC enc */
  
  /*
   * These three types are reserved for future use.
   */
  #define LINKTYPE_LANE8023	110		/* ATM LANE + 802.3 */
  #define LINKTYPE_HIPPI		111		/* NetBSD HIPPI */
  #define LINKTYPE_HDLC		112		/* NetBSD HDLC framing */
  
  #define LINKTYPE_LINUX_SLL	113		/* Linux cooked socket capture */
  #define LINKTYPE_LTALK		114		/* Apple LocalTalk hardware */
  #define LINKTYPE_ECONET		115		/* Acorn Econet */
  
  /*
   * Reserved for use with OpenBSD ipfilter.
   */
  #define LINKTYPE_IPFILTER	116
  
  #define LINKTYPE_PFLOG		117		/* OpenBSD DLT_PFLOG */
  #define LINKTYPE_CISCO_IOS	118		/* For Cisco-internal use */
  #define LINKTYPE_IEEE802_11_PRISM 119		/* 802.11 plus Prism II monitor mode radio metadata header */
  #define LINKTYPE_IEEE802_11_AIRONET 120		/* 802.11 plus FreeBSD Aironet driver radio metadata header */
  
  /*
   * Reserved for Siemens HiPath HDLC.
   */
  #define LINKTYPE_HHDLC		121
  
  #define LINKTYPE_IP_OVER_FC	122		/* RFC 2625 IP-over-Fibre Channel */
  #define LINKTYPE_SUNATM		123		/* Solaris+SunATM */
  
  /*
   * Reserved as per request from Kent Dahlgren <kent@praesum.com>
   * for private use.
   */
  #define LINKTYPE_RIO		124		/* RapidIO */
  #define LINKTYPE_PCI_EXP	125		/* PCI Express */
  #define LINKTYPE_AURORA		126		/* Xilinx Aurora link layer */
  
  #define LINKTYPE_IEEE802_11_RADIOTAP 127	/* 802.11 plus radiotap radio metadata header */
  
  /*
   * Reserved for the TZSP encapsulation, as per request from
   * Chris Waters <chris.waters@networkchemistry.com>
   * TZSP is a generic encapsulation for any other link type,
   * which includes a means to include meta-information
   * with the packet, e.g. signal strength and channel
   * for 802.11 packets.
   */
  #define LINKTYPE_TZSP		128		/* Tazmen Sniffer Protocol */
  
  #define LINKTYPE_ARCNET_LINUX	129		/* Linux-style headers */
  
  /*
   * Juniper-private data link types, as per request from
   * Hannes Gredler <hannes@juniper.net>.  The corresponding
   * DLT_s are used for passing on chassis-internal
   * metainformation such as QOS profiles, etc..
   */
  #define LINKTYPE_JUNIPER_MLPPP  130
  #define LINKTYPE_JUNIPER_MLFR   131
  #define LINKTYPE_JUNIPER_ES     132
  #define LINKTYPE_JUNIPER_GGSN   133
  #define LINKTYPE_JUNIPER_MFR    134
  #define LINKTYPE_JUNIPER_ATM2   135
  #define LINKTYPE_JUNIPER_SERVICES 136
  #define LINKTYPE_JUNIPER_ATM1   137
  
  #define LINKTYPE_APPLE_IP_OVER_IEEE1394 138	/* Apple IP-over-IEEE 1394 cooked header */
  
  #define LINKTYPE_MTP2_WITH_PHDR	139
  #define LINKTYPE_MTP2		140
  #define LINKTYPE_MTP3		141
  #define LINKTYPE_SCCP		142
  
  #define LINKTYPE_DOCSIS		143		/* DOCSIS MAC frames */
  
  #define LINKTYPE_LINUX_IRDA	144		/* Linux-IrDA */
  
  /*
   * Reserved for IBM SP switch and IBM Next Federation switch.
   */
  #define LINKTYPE_IBM_SP		145
  #define LINKTYPE_IBM_SN		146
  
  /*
   * Reserved for private use.  If you have some link-layer header type
   * that you want to use within your organization, with the capture files
   * using that link-layer header type not ever be sent outside your
   * organization, you can use these values.
   *
   * No libpcap release will use these for any purpose, nor will any
   * tcpdump release use them, either.
   *
   * Do *NOT* use these in capture files that you expect anybody not using
   * your private versions of capture-file-reading tools to read; in
   * particular, do *NOT* use them in products, otherwise you may find that
   * people won't be able to use tcpdump, or snort, or Ethereal, or... to
   * read capture files from your firewall/intrusion detection/traffic
   * monitoring/etc. appliance, or whatever product uses that LINKTYPE_ value,
   * and you may also find that the developers of those applications will
   * not accept patches to let them read those files.
   *
   * Also, do not use them if somebody might send you a capture using them
   * for *their* private type and tools using them for *your* private type
   * would have to read them.
   *
   * Instead, in those cases, ask "tcpdump-workers@lists.tcpdump.org" for a
   * new DLT_ and LINKTYPE_ value, as per the comment in pcap/bpf.h, and use
   * the type you're given.
   */
  #define LINKTYPE_USER0		147
  #define LINKTYPE_USER1		148
  #define LINKTYPE_USER2		149
  #define LINKTYPE_USER3		150
  #define LINKTYPE_USER4		151
  #define LINKTYPE_USER5		152
  #define LINKTYPE_USER6		153
  #define LINKTYPE_USER7		154
  #define LINKTYPE_USER8		155
  #define LINKTYPE_USER9		156
  #define LINKTYPE_USER10		157
  #define LINKTYPE_USER11		158
  #define LINKTYPE_USER12		159
  #define LINKTYPE_USER13		160
  #define LINKTYPE_USER14		161
  #define LINKTYPE_USER15		162
  
  /*
   * For future use with 802.11 captures - defined by AbsoluteValue
   * Systems to store a number of bits of link-layer information
   * including radio information:
   *
   *	http://www.shaftnet.org/~pizza/software/capturefrm.txt
   */
  #define LINKTYPE_IEEE802_11_AVS	163	/* 802.11 plus AVS radio metadata header */
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.  The corresponding
   * DLT_s are used for passing on chassis-internal
   * metainformation such as QOS profiles, etc..
   */
  #define LINKTYPE_JUNIPER_MONITOR 164
  
  /*
   * BACnet MS/TP frames.
   */
  #define LINKTYPE_BACNET_MS_TP	165
  
  /*
   * Another PPP variant as per request from Karsten Keil <kkeil@suse.de>.
   *
   * This is used in some OSes to allow a kernel socket filter to distinguish
   * between incoming and outgoing packets, on a socket intended to
   * supply pppd with outgoing packets so it can do dial-on-demand and
   * hangup-on-lack-of-demand; incoming packets are filtered out so they
   * don't cause pppd to hold the connection up (you don't want random
   * input packets such as port scans, packets from old lost connections,
   * etc. to force the connection to stay up).
   *
   * The first byte of the PPP header (0xff03) is modified to accomodate
   * the direction - 0x00 = IN, 0x01 = OUT.
   */
  #define LINKTYPE_PPP_PPPD	166
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.  The DLT_s are used
   * for passing on chassis-internal metainformation such as
   * QOS profiles, cookies, etc..
   */
  #define LINKTYPE_JUNIPER_PPPOE     167
  #define LINKTYPE_JUNIPER_PPPOE_ATM 168
  
  #define LINKTYPE_GPRS_LLC	169		/* GPRS LLC */
  #define LINKTYPE_GPF_T		170		/* GPF-T (ITU-T G.7041/Y.1303) */
  #define LINKTYPE_GPF_F		171		/* GPF-T (ITU-T G.7041/Y.1303) */
  
  /*
   * Requested by Oolan Zimmer <oz@gcom.com> for use in Gcom's T1/E1 line
   * monitoring equipment.
   */
  #define LINKTYPE_GCOM_T1E1	172
  #define LINKTYPE_GCOM_SERIAL	173
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.  The DLT_ is used
   * for internal communication to Physical Interface Cards (PIC)
   */
  #define LINKTYPE_JUNIPER_PIC_PEER    174
  
  /*
   * Link types requested by Gregor Maier <gregor@endace.com> of Endace
   * Measurement Systems.  They add an ERF header (see
   * http://www.endace.com/support/EndaceRecordFormat.pdf) in front of
   * the link-layer header.
   */
  #define LINKTYPE_ERF_ETH	175	/* Ethernet */
  #define LINKTYPE_ERF_POS	176	/* Packet-over-SONET */
  
  /*
   * Requested by Daniele Orlandi <daniele@orlandi.com> for raw LAPD
   * for vISDN (http://www.orlandi.com/visdn/).  Its link-layer header
   * includes additional information before the LAPD header, so it's
   * not necessarily a generic LAPD header.
   */
  #define LINKTYPE_LINUX_LAPD	177
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.
   * The Link Types are used for prepending meta-information
   * like interface index, interface name
   * before standard Ethernet, PPP, Frelay & C-HDLC Frames
   */
  #define LINKTYPE_JUNIPER_ETHER  178
  #define LINKTYPE_JUNIPER_PPP    179
  #define LINKTYPE_JUNIPER_FRELAY 180
  #define LINKTYPE_JUNIPER_CHDLC  181
  
  /*
   * Multi Link Frame Relay (FRF.16)
   */
  #define LINKTYPE_MFR            182
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.
   * The DLT_ is used for internal communication with a
   * voice Adapter Card (PIC)
   */
  #define LINKTYPE_JUNIPER_VP     183
  
  /*
   * Arinc 429 frames.
   * DLT_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
   * Every frame contains a 32bit A429 label.
   * More documentation on Arinc 429 can be found at
   * http://www.condoreng.com/support/downloads/tutorials/ARINCTutorial.pdf
   */
  #define LINKTYPE_A429           184
  
  /*
   * Arinc 653 Interpartition Communication messages.
   * DLT_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
   * Please refer to the A653-1 standard for more information.
   */
  #define LINKTYPE_A653_ICM       185
  
  /*
   * USB packets, beginning with a USB setup header; requested by
   * Paolo Abeni <paolo.abeni@email.it>.
   */
  #define LINKTYPE_USB		186
  
  /*
   * Bluetooth HCI UART transport layer (part H:4); requested by
   * Paolo Abeni.
   */
  #define LINKTYPE_BLUETOOTH_HCI_H4	187
  
  /*
   * IEEE 802.16 MAC Common Part Sublayer; requested by Maria Cruz
   * <cruz_petagay@bah.com>.
   */
  #define LINKTYPE_IEEE802_16_MAC_CPS	188
  
  /*
   * USB packets, beginning with a Linux USB header; requested by
   * Paolo Abeni <paolo.abeni@email.it>.
   */
  #define LINKTYPE_USB_LINUX		189
  
  /*
   * Controller Area Network (CAN) v. 2.0B packets.
   * DLT_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
   * Used to dump CAN packets coming from a CAN Vector board.
   * More documentation on the CAN v2.0B frames can be found at
   * http://www.can-cia.org/downloads/?269
   */
  #define LINKTYPE_CAN20B         190
  
  /*
   * IEEE 802.15.4, with address fields padded, as is done by Linux
   * drivers; requested by Juergen Schimmer.
   */
  #define LINKTYPE_IEEE802_15_4_LINUX	191
  
  /*
   * Per Packet Information encapsulated packets.
   * LINKTYPE_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
   */
  #define LINKTYPE_PPI			192
  
  /*
   * Header for 802.16 MAC Common Part Sublayer plus a radiotap radio header;
   * requested by Charles Clancy.
   */
  #define LINKTYPE_IEEE802_16_MAC_CPS_RADIO	193
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.
   * The DLT_ is used for internal communication with a
   * integrated service module (ISM).
   */
  #define LINKTYPE_JUNIPER_ISM    194
  
  /*
   * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
   * nothing); requested by Mikko Saarnivala <mikko.saarnivala@sensinode.com>.
   */
  #define LINKTYPE_IEEE802_15_4	195
  
  /*
   * Various link-layer types, with a pseudo-header, for SITA
   * (http://www.sita.aero/); requested by Fulko Hew (fulko.hew@gmail.com).
   */
  #define LINKTYPE_SITA		196
  
  /*
   * Various link-layer types, with a pseudo-header, for Endace DAG cards;
   * encapsulates Endace ERF records.  Requested by Stephen Donnelly
   * <stephen@endace.com>.
   */
  #define LINKTYPE_ERF		197
  
  /*
   * Special header prepended to Ethernet packets when capturing from a
   * u10 Networks board.  Requested by Phil Mulholland
   * <phil@u10networks.com>.
   */
  #define LINKTYPE_RAIF1		198
  
  /*
   * IPMB packet for IPMI, beginning with the I2C slave address, followed
   * by the netFn and LUN, etc..  Requested by Chanthy Toeung
   * <chanthy.toeung@ca.kontron.com>.
   */
  #define LINKTYPE_IPMB		199
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.
   * The DLT_ is used for capturing data on a secure tunnel interface.
   */
  #define LINKTYPE_JUNIPER_ST     200
  
  /*
   * Bluetooth HCI UART transport layer (part H:4), with pseudo-header
   * that includes direction information; requested by Paolo Abeni.
   */
  #define LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR	201
  
  /*
   * AX.25 packet with a 1-byte KISS header; see
   *
   *	http://www.ax25.net/kiss.htm
   *
   * as per Richard Stearn <richard@rns-stearn.demon.co.uk>.
   */
  #define LINKTYPE_AX25_KISS	202
  
  /*
   * LAPD packets from an ISDN channel, starting with the address field,
   * with no pseudo-header.
   * Requested by Varuna De Silva <varunax@gmail.com>.
   */
  #define LINKTYPE_LAPD		203
  
  /*
   * Variants of various link-layer headers, with a one-byte direction
   * pseudo-header prepended - zero means "received by this host",
   * non-zero (any non-zero value) means "sent by this host" - as per
   * Will Barker <w.barker@zen.co.uk>.
   */
  #define LINKTYPE_PPP_WITH_DIR	204	/* PPP */
  #define LINKTYPE_C_HDLC_WITH_DIR 205	/* Cisco HDLC */
  #define LINKTYPE_FRELAY_WITH_DIR 206	/* Frame Relay */
  #define LINKTYPE_LAPB_WITH_DIR	207	/* LAPB */
  
  /*
   * 208 is reserved for an as-yet-unspecified proprietary link-layer
   * type, as requested by Will Barker.
   */
  
  /*
   * IPMB with a Linux-specific pseudo-header; as requested by Alexey Neyman
   * <avn@pigeonpoint.com>.
   */
  #define LINKTYPE_IPMB_LINUX	209
  
  /*
   * FlexRay automotive bus - http://www.flexray.com/ - as requested
   * by Hannes Kaelber <hannes.kaelber@x2e.de>.
   */
  #define LINKTYPE_FLEXRAY	210
  
  /*
   * Media Oriented Systems Transport (MOST) bus for multimedia
   * transport - http://www.mostcooperation.com/ - as requested
   * by Hannes Kaelber <hannes.kaelber@x2e.de>.
   */
  #define LINKTYPE_MOST		211
  
  /*
   * Local Interconnect Network (LIN) bus for vehicle networks -
   * http://www.lin-subbus.org/ - as requested by Hannes Kaelber
   * <hannes.kaelber@x2e.de>.
   */
  #define LINKTYPE_LIN		212
  
  /*
   * X2E-private data link type used for serial line capture,
   * as requested by Hannes Kaelber <hannes.kaelber@x2e.de>.
   */
  #define LINKTYPE_X2E_SERIAL	213
  
  /*
   * X2E-private data link type used for the Xoraya data logger
   * family, as requested by Hannes Kaelber <hannes.kaelber@x2e.de>.
   */
  #define LINKTYPE_X2E_XORAYA	214
  
  /*
   * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
   * nothing), but with the PHY-level data for non-ASK PHYs (4 octets
   * of 0 as preamble, one octet of SFD, one octet of frame length+
   * reserved bit, and then the MAC-layer data, starting with the
   * frame control field).
   *
   * Requested by Max Filippov <jcmvbkbc@gmail.com>.
   */
  #define LINKTYPE_IEEE802_15_4_NONASK_PHY	215
  
  /*
   * David Gibson <david@gibson.dropbear.id.au> requested this for
   * captures from the Linux kernel /dev/input/eventN devices. This
   * is used to communicate keystrokes and mouse movements from the
   * Linux kernel to display systems, such as Xorg.
   */
  #define LINKTYPE_LINUX_EVDEV	216
  
  /*
   * GSM Um and Abis interfaces, preceded by a "gsmtap" header.
   *
   * Requested by Harald Welte <laforge@gnumonks.org>.
   */
  #define LINKTYPE_GSMTAP_UM	217
  #define LINKTYPE_GSMTAP_ABIS	218
  
  /*
   * MPLS, with an MPLS label as the link-layer header.
   * Requested by Michele Marchetto <michele@openbsd.org> on behalf
   * of OpenBSD.
   */
  #define LINKTYPE_MPLS		219
  
  /*
   * USB packets, beginning with a Linux USB header, with the USB header
   * padded to 64 bytes; required for memory-mapped access.
   */
  #define LINKTYPE_USB_LINUX_MMAPPED		220
  
  /*
   * DECT packets, with a pseudo-header; requested by
   * Matthias Wenzel <tcpdump@mazzoo.de>.
   */
  #define LINKTYPE_DECT		221
  
  /*
   * From: "Lidwa, Eric (GSFC-582.0)[SGT INC]" <eric.lidwa-1@nasa.gov>
   * Date: Mon, 11 May 2009 11:18:30 -0500
   *
   * DLT_AOS. We need it for AOS Space Data Link Protocol.
   *   I have already written dissectors for but need an OK from
   *   legal before I can submit a patch.
   *
   */
  #define LINKTYPE_AOS		222
  
  /*
   * Wireless HART (Highway Addressable Remote Transducer)
   * From the HART Communication Foundation
   * IES/PAS 62591
   *
   * Requested by Sam Roberts <vieuxtech@gmail.com>.
   */
  #define LINKTYPE_WIHART		223
  
  /*
   * Fibre Channel FC-2 frames, beginning with a Frame_Header.
   * Requested by Kahou Lei <kahou82@gmail.com>.
   */
  #define LINKTYPE_FC_2		224
  
  /*
   * Fibre Channel FC-2 frames, beginning with an encoding of the
   * SOF, and ending with an encoding of the EOF.
   *
   * The encodings represent the frame delimiters as 4-byte sequences
   * representing the corresponding ordered sets, with K28.5
   * represented as 0xBC, and the D symbols as the corresponding
   * byte values; for example, SOFi2, which is K28.5 - D21.5 - D1.2 - D21.2,
   * is represented as 0xBC 0xB5 0x55 0x55.
   *
   * Requested by Kahou Lei <kahou82@gmail.com>.
   */
  #define LINKTYPE_FC_2_WITH_FRAME_DELIMS		225
  
  /*
   * Solaris ipnet pseudo-header; requested by Darren Reed <Darren.Reed@Sun.COM>.
   *
   * The pseudo-header starts with a one-byte version number; for version 2,
   * the pseudo-header is:
   *
   * struct dl_ipnetinfo {
   *     u_int8_t   dli_version;
   *     u_int8_t   dli_family;
   *     u_int16_t  dli_htype;
   *     u_int32_t  dli_pktlen;
   *     u_int32_t  dli_ifindex;
   *     u_int32_t  dli_grifindex;
   *     u_int32_t  dli_zsrc;
   *     u_int32_t  dli_zdst;
   * };
   *
   * dli_version is 2 for the current version of the pseudo-header.
   *
   * dli_family is a Solaris address family value, so it's 2 for IPv4
   * and 26 for IPv6.
   *
   * dli_htype is a "hook type" - 0 for incoming packets, 1 for outgoing
   * packets, and 2 for packets arriving from another zone on the same
   * machine.
   *
   * dli_pktlen is the length of the packet data following the pseudo-header
   * (so the captured length minus dli_pktlen is the length of the
   * pseudo-header, assuming the entire pseudo-header was captured).
   *
   * dli_ifindex is the interface index of the interface on which the
   * packet arrived.
   *
   * dli_grifindex is the group interface index number (for IPMP interfaces).
   *
   * dli_zsrc is the zone identifier for the source of the packet.
   *
   * dli_zdst is the zone identifier for the destination of the packet.
   *
   * A zone number of 0 is the global zone; a zone number of 0xffffffff
   * means that the packet arrived from another host on the network, not
   * from another zone on the same machine.
   *
   * An IPv4 or IPv6 datagram follows the pseudo-header; dli_family indicates
   * which of those it is.
   */
  #define LINKTYPE_IPNET		226
  
  /*
   * CAN (Controller Area Network) frames, with a pseudo-header as supplied
   * by Linux SocketCAN.  See Documentation/networking/can.txt in the Linux
   * source.
   *
   * Requested by Felix Obenhuber <felix@obenhuber.de>.
   */
  #define LINKTYPE_CAN_SOCKETCAN	227
  
  /*
   * Raw IPv4/IPv6; different from DLT_RAW in that the DLT_ value specifies
   * whether it's v4 or v6.  Requested by Darren Reed <Darren.Reed@Sun.COM>.
   */
  #define LINKTYPE_IPV4		228
  #define LINKTYPE_IPV6		229
  
  /*
   * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
   * nothing), and with no FCS at the end of the frame; requested by
   * Jon Smirl <jonsmirl@gmail.com>.
   */
  #define LINKTYPE_IEEE802_15_4_NOFCS		230
  
  /*
   * Raw D-Bus:
   *
   *	http://www.freedesktop.org/wiki/Software/dbus
   *
   * messages:
   *
   *	http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-messages
   *
   * starting with the endianness flag, followed by the message type, etc.,
   * but without the authentication handshake before the message sequence:
   *
   *	http://dbus.freedesktop.org/doc/dbus-specification.html#auth-protocol
   *
   * Requested by Martin Vidner <martin@vidner.net>.
   */
  #define LINKTYPE_DBUS		231
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.
   */
  #define LINKTYPE_JUNIPER_VS			232
  #define LINKTYPE_JUNIPER_SRX_E2E		233
  #define LINKTYPE_JUNIPER_FIBRECHANNEL		234
  
  /*
   * DVB-CI (DVB Common Interface for communication between a PC Card
   * module and a DVB receiver).  See
   *
   *	http://www.kaiser.cx/pcap-dvbci.html
   *
   * for the specification.
   *
   * Requested by Martin Kaiser <martin@kaiser.cx>.
   */
  #define LINKTYPE_DVB_CI		235
  
  /*
   * Variant of 3GPP TS 27.010 multiplexing protocol.  Requested
   * by Hans-Christoph Schemmel <hans-christoph.schemmel@cinterion.com>.
   */
  #define LINKTYPE_MUX27010	236
  
  /*
   * STANAG 5066 D_PDUs.  Requested by M. Baris Demiray
   * <barisdemiray@gmail.com>.
   */
  #define LINKTYPE_STANAG_5066_D_PDU		237
  
  /*
   * Juniper-private data link type, as per request from
   * Hannes Gredler <hannes@juniper.net>.
   */
  #define LINKTYPE_JUNIPER_ATM_CEMIC		238
  
  /*
   * NetFilter LOG messages
   * (payload of netlink NFNL_SUBSYS_ULOG/NFULNL_MSG_PACKET packets)
   *
   * Requested by Jakub Zawadzki <darkjames-ws@darkjames.pl>
   */
  #define LINKTYPE_NFLOG		239
  
  /*
   * Hilscher Gesellschaft fuer Systemautomation mbH link-layer type
   * for Ethernet packets with a 4-byte pseudo-header and always
   * with the payload including the FCS, as supplied by their
   * netANALYZER hardware and software.
   *
   * Requested by Holger P. Frommer <HPfrommer@hilscher.com>
   */
  #define LINKTYPE_NETANALYZER	240
  
  /*
   * Hilscher Gesellschaft fuer Systemautomation mbH link-layer type
   * for Ethernet packets with a 4-byte pseudo-header and FCS and
   * 1 byte of SFD, as supplied by their netANALYZER hardware and
   * software.
   *
   * Requested by Holger P. Frommer <HPfrommer@hilscher.com>
   */
  #define LINKTYPE_NETANALYZER_TRANSPARENT	241
  
  /*
   * IP-over-InfiniBand, as specified by RFC 4391.
   *
   * Requested by Petr Sumbera <petr.sumbera@oracle.com>.
   */
  #define LINKTYPE_IPOIB		242
  
  /*
   * MPEG-2 transport stream (ISO 13818-1/ITU-T H.222.0).
   *
   * Requested by Guy Martin <gmsoft@tuxicoman.be>.
   */
  #define LINKTYPE_MPEG_2_TS	243
  
  /*
   * ng4T GmbH's UMTS Iub/Iur-over-ATM and Iub/Iur-over-IP format as
   * used by their ng40 protocol tester.
   *
   * Requested by Jens Grimmer <jens.grimmer@ng4t.com>.
   */
  #define LINKTYPE_NG40		244
  
  /*
   * Pseudo-header giving adapter number and flags, followed by an NFC
   * (Near-Field Communications) Logical Link Control Protocol (LLCP) PDU,
   * as specified by NFC Forum Logical Link Control Protocol Technical
   * Specification LLCP 1.1.
   *
   * Requested by Mike Wakerly <mikey@google.com>.
   */
  #define LINKTYPE_NFC_LLCP	245
  
  /*
   * pfsync output; DLT_PFSYNC is 18, which collides with DLT_CIP in
   * SuSE 6.3, on OpenBSD, NetBSD, DragonFly BSD, and Mac OS X, and
   * is 121, which collides with DLT_HHDLC, in FreeBSD.  We pick a
   * shiny new link-layer header type value that doesn't collide with
   * anything, in the hopes that future pfsync savefiles, if any,
   * won't require special hacks to distinguish from other savefiles.
   *
   */
  #define LINKTYPE_PFSYNC		246
  
  /*
   * Raw InfiniBand packets, starting with the Local Routing Header.
   *
   * Requested by Oren Kladnitsky <orenk@mellanox.com>.
   */
  #define LINKTYPE_INFINIBAND	247
  
  /*
   * SCTP, with no lower-level protocols (i.e., no IPv4 or IPv6).
   *
   * Requested by Michael Tuexen <Michael.Tuexen@lurchi.franken.de>.
   */
  #define LINKTYPE_SCTP		248
  
  /*
   * USB packets, beginning with a USBPcap header.
   *
   * Requested by Tomasz Mon <desowin@gmail.com>
   */
  #define LINKTYPE_USBPCAP	249
  
  /*
   * Schweitzer Engineering Laboratories "RTAC" product serial-line
   * packets.
   *
   * Requested by Chris Bontje <chris_bontje@selinc.com>.
   */
  #define DLT_RTAC_SERIAL		250
  
  /*
   * Bluetooth Low Energy air interface link-layer packets.
   *
   * Requested by Mike Kershaw <dragorn@kismetwireless.net>.
   */
  #define LINKTYPE_BLUETOOTH_LE_LL	251
  
  /*
   * Link-layer header type for upper-protocol layer PDU saves from wireshark.
   *
   * the actual contents are determined by two TAGs stored with each
   * packet:
   *   EXP_PDU_TAG_LINKTYPE          the link type (LINKTYPE_ value) of the
   *				   original packet.
   *
   *   EXP_PDU_TAG_PROTO_NAME        the name of the wireshark dissector
   * 				   that can make sense of the data stored.
   */
  #define LINKTYPE_WIRESHARK_UPPER_PDU	252
  
  /*
   * Link-layer header type for the netlink protocol (nlmon devices).
   */
  #define LINKTYPE_NETLINK		253
  
  /*
   * Bluetooth Linux Monitor headers for the BlueZ stack.
   */
  #define LINKTYPE_BLUETOOTH_LINUX_MONITOR	254
  
  /*
   * Bluetooth Basic Rate/Enhanced Data Rate baseband packets, as
   * captured by Ubertooth.
   */
  #define LINKTYPE_BLUETOOTH_BREDR_BB	255
  
  /*
   * Bluetooth Low Energy link layer packets, as captured by Ubertooth.
   */
  #define LINKTYPE_BLUETOOTH_LE_LL_WITH_PHDR	256
  
  /*
   * PROFIBUS data link layer.
   */
  #define LINKTYPE_PROFIBUS_DL		257
  
  
  /*
   * Apple's DLT_PKTAP headers.
   *
   * Sadly, the folks at Apple either had no clue that the DLT_USERn values
   * are for internal use within an organization and partners only, and
   * didn't know that the right way to get a link-layer header type is to
   * ask tcpdump.org for one, or knew and didn't care, so they just
   * used DLT_USER2, which causes problems for everything except for
   * their version of tcpdump.
   *
   * So I'll just give them one; hopefully this will show up in a
   * libpcap release in time for them to get this into 10.10 Big Sur
   * or whatever Mavericks' successor is called.  LINKTYPE_PKTAP
   * will be 258 *even on OS X*; that is *intentional*, so that
   * PKTAP files look the same on *all* OSes (different OSes can have
   * different numerical values for a given DLT_, but *MUST NOT* have
   * different values for what goes in a file, as files can be moved
   * between OSes!).
   */
  #define LINKTYPE_PKTAP		258
  
  /*
   * Ethernet packets preceded by a header giving the last 6 octets
   * of the preamble specified by 802.3-2012 Clause 65, section
   * 65.1.3.2 "Transmit".
   */
  #define LINKTYPE_EPON		259
  
  /*
   * IPMI trace packets, as specified by Table 3-20 "Trace Data Block Format"
   * in the PICMG HPM.2 specification.
   */
  #define LINKTYPE_IPMI_HPM_2	260
  
  /*
   * per  Joshua Wright <jwright@hasborg.com>, formats for Zwave captures.
   */
  #define LINKTYPE_ZWAVE_R1_R2	261
  #define LINKTYPE_ZWAVE_R3	262
  
  #define LINKTYPE_MATCHING_MAX	262		/* highest value in the "matching" range */
  
  static struct linktype_map {
  	int	dlt;
  	int	linktype;
  } map[] = {
  	/*
  	 * These DLT_* codes have LINKTYPE_* codes with values identical
  	 * to the values of the corresponding DLT_* code.
  	 */
  	{ DLT_NULL,		LINKTYPE_NULL },
  	{ DLT_EN10MB,		LINKTYPE_ETHERNET },
  	{ DLT_EN3MB,		LINKTYPE_EXP_ETHERNET },
  	{ DLT_AX25,		LINKTYPE_AX25 },
  	{ DLT_PRONET,		LINKTYPE_PRONET },
  	{ DLT_CHAOS,		LINKTYPE_CHAOS },
  	{ DLT_IEEE802,		LINKTYPE_IEEE802_5 },
  	{ DLT_ARCNET,		LINKTYPE_ARCNET_BSD },
  	{ DLT_SLIP,		LINKTYPE_SLIP },
  	{ DLT_PPP,		LINKTYPE_PPP },
  	{ DLT_FDDI,	 	LINKTYPE_FDDI },
  	{ DLT_SYMANTEC_FIREWALL, LINKTYPE_SYMANTEC_FIREWALL },
  
  	/*
  	 * These DLT_* codes have different values on different
  	 * platforms; we map them to LINKTYPE_* codes that
  	 * have values that should never be equal to any DLT_*
  	 * code.
  	 */
  #ifdef DLT_FR
  	/* BSD/OS Frame Relay */
  	{ DLT_FR,		LINKTYPE_FRELAY },
  #endif
  
  	{ DLT_ATM_RFC1483, 	LINKTYPE_ATM_RFC1483 },
  	{ DLT_RAW,		LINKTYPE_RAW },
  	{ DLT_SLIP_BSDOS,	LINKTYPE_SLIP_BSDOS },
  	{ DLT_PPP_BSDOS,	LINKTYPE_PPP_BSDOS },
  
  	/* BSD/OS Cisco HDLC */
  	{ DLT_C_HDLC,		LINKTYPE_C_HDLC },
  
  	/*
  	 * These DLT_* codes are not on all platforms, but, so far,
  	 * there don't appear to be any platforms that define
  	 * other codes with those values; we map them to
  	 * different LINKTYPE_* values anyway, just in case.
  	 */
  
  	/* Linux ATM Classical IP */
  	{ DLT_ATM_CLIP,		LINKTYPE_ATM_CLIP },
  
  	/* NetBSD sync/async serial PPP (or Cisco HDLC) */
  	{ DLT_PPP_SERIAL,	LINKTYPE_PPP_HDLC },
  
  	/* NetBSD PPP over Ethernet */
  	{ DLT_PPP_ETHER,	LINKTYPE_PPP_ETHER },
  
  	/*
  	 * All LINKTYPE_ values between LINKTYPE_MATCHING_MIN
  	 * and LINKTYPE_MATCHING_MAX are mapped to identical
  	 * DLT_ values.
  	 */
  
  	{ -1,			-1 }
  };
  
  int
  dlt_to_linktype(int dlt)
  {
  	int i;
  
  	/*
  	 * DLTs that, on some platforms, have values in the matching range
  	 * but that *don't* have the same value as the corresponding
  	 * LINKTYPE because, for some reason, not all OSes have the
  	 * same value for that DLT (note that the DLT's value might be
  	 * outside the matching range on some of those OSes).
  	 */
  	if (dlt == DLT_PFSYNC)
  		return (LINKTYPE_PFSYNC);
  	if (dlt == DLT_PKTAP)
  		return (LINKTYPE_PKTAP);
  
  	/*
  	 * For all other values in the matching range, the DLT
  	 * value is the same as the LINKTYPE value.
  	 */
  	if (dlt >= DLT_MATCHING_MIN && dlt <= DLT_MATCHING_MAX)
  		return (dlt);
  
  	/*
  	 * Map the values outside that range.
  	 */
  	for (i = 0; map[i].dlt != -1; i++) {
  		if (map[i].dlt == dlt)
  			return (map[i].linktype);
  	}
  
  	/*
  	 * If we don't have a mapping for this DLT, return an
  	 * error; that means that this is a value with no corresponding
  	 * LINKTYPE, and we need to assign one.
  	 */
  	return (-1);
  }
  
  int
  linktype_to_dlt(int linktype)
  {
  	int i;
  
  	/*
  	 * LINKTYPEs in the matching range that *don't*
  	 * have the same value as the corresponding DLTs
  	 * because, for some reason, not all OSes have the
  	 * same value for that DLT.
  	 */
  	if (linktype == LINKTYPE_PFSYNC)
  		return (DLT_PFSYNC);
  	if (linktype == LINKTYPE_PKTAP)
  		return (DLT_PKTAP);
  
  	/*
  	 * For all other values in the matching range, the LINKTYPE
  	 * value is the same as the DLT value.
  	 */
  	if (linktype >= LINKTYPE_MATCHING_MIN &&
  	    linktype <= LINKTYPE_MATCHING_MAX)
  		return (linktype);
  
  	/*
  	 * Map the values outside that range.
  	 */
  	for (i = 0; map[i].linktype != -1; i++) {
  		if (map[i].linktype == linktype)
  			return (map[i].dlt);
  	}
  
  	/*
  	 * If we don't have an entry for this LINKTYPE, return
  	 * the link type value; it may be a DLT from an older
  	 * version of libpcap.
  	 */
  	return linktype;
  }
  
  /*
   * The DLT_USB_LINUX and DLT_USB_LINUX_MMAPPED headers are in host
   * byte order when capturing (it's supplied directly from a
   * memory-mapped buffer shared by the kernel).
   *
   * When reading a DLT_USB_LINUX or DLT_USB_LINUX_MMAPPED capture file,
   * we need to convert it from the byte order of the host that wrote
   * the file to this host's byte order.
   */
  static void
  swap_linux_usb_header(const struct pcap_pkthdr *hdr, u_char *buf,
      int header_len_64_bytes)
  {
  	pcap_usb_header_mmapped *uhdr = (pcap_usb_header_mmapped *)buf;
  	bpf_u_int32 offset = 0;
  
  	/*
  	 * "offset" is the offset *past* the field we're swapping;
  	 * we skip the field *before* checking to make sure
  	 * the captured data length includes the entire field.
  	 */
  
  	/*
  	 * The URB id is a totally opaque value; do we really need to
  	 * convert it to the reading host's byte order???
  	 */
  	offset += 8;			/* skip past id */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->id = SWAPLL(uhdr->id);
  
  	offset += 4;			/* skip past various 1-byte fields */
  
  	offset += 2;			/* skip past bus_id */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->bus_id = SWAPSHORT(uhdr->bus_id);
  
  	offset += 2;			/* skip past various 1-byte fields */
  
  	offset += 8;			/* skip past ts_sec */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->ts_sec = SWAPLL(uhdr->ts_sec);
  
  	offset += 4;			/* skip past ts_usec */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->ts_usec = SWAPLONG(uhdr->ts_usec);
  
  	offset += 4;			/* skip past status */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->status = SWAPLONG(uhdr->status);
  
  	offset += 4;			/* skip past urb_len */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->urb_len = SWAPLONG(uhdr->urb_len);
  
  	offset += 4;			/* skip past data_len */
  	if (hdr->caplen < offset)
  		return;
  	uhdr->data_len = SWAPLONG(uhdr->data_len);
  
  	if (uhdr->transfer_type == URB_ISOCHRONOUS) {
  		offset += 4;			/* skip past s.iso.error_count */
  		if (hdr->caplen < offset)
  			return;
  		uhdr->s.iso.error_count = SWAPLONG(uhdr->s.iso.error_count);
  
  		offset += 4;			/* skip past s.iso.numdesc */
  		if (hdr->caplen < offset)
  			return;
  		uhdr->s.iso.numdesc = SWAPLONG(uhdr->s.iso.numdesc);
  	} else
  		offset += 8;			/* skip USB setup header */
  
  	/*
  	 * With the old header, there are no isochronous descriptors
  	 * after the header.
  	 *
  	 * With the new header, the actual number of descriptors in
  	 * the header is not s.iso.numdesc, it's ndesc - only the
  	 * first N descriptors, for some value of N, are put into
  	 * the header, and ndesc is set to the actual number copied.
  	 * In addition, if s.iso.numdesc is negative, no descriptors
  	 * are captured, and ndesc is set to 0.
  	 */
  	if (header_len_64_bytes) {
  		/*
  		 * This is either the "version 1" header, with
  		 * 16 bytes of additional fields at the end, or
  		 * a "version 0" header from a memory-mapped
  		 * capture, with 16 bytes of zeroed-out padding
  		 * at the end.  Byte swap them as if this were
  		 * a "version 1" header.
  		 */
  		offset += 4;			/* skip past interval */
  		if (hdr->caplen < offset)
  			return;
  		uhdr->interval = SWAPLONG(uhdr->interval);
  
  		offset += 4;			/* skip past start_frame */
  		if (hdr->caplen < offset)
  			return;
  		uhdr->start_frame = SWAPLONG(uhdr->start_frame);
  
  		offset += 4;			/* skip past xfer_flags */
  		if (hdr->caplen < offset)
  			return;
  		uhdr->xfer_flags = SWAPLONG(uhdr->xfer_flags);
  
  		offset += 4;			/* skip past ndesc */
  		if (hdr->caplen < offset)
  			return;
  		uhdr->ndesc = SWAPLONG(uhdr->ndesc);
  
  		if (uhdr->transfer_type == URB_ISOCHRONOUS) {
  			/* swap the values in struct linux_usb_isodesc */
  			usb_isodesc *pisodesc;
  			u_int32_t i;
  
  			pisodesc = (usb_isodesc *)(void *)(buf+offset);
  			for (i = 0; i < uhdr->ndesc; i++) {
  				offset += 4;		/* skip past status */
  				if (hdr->caplen < offset)
  					return;
  				pisodesc->status = SWAPLONG(pisodesc->status);
  
  				offset += 4;		/* skip past offset */
  				if (hdr->caplen < offset)
  					return;
  				pisodesc->offset = SWAPLONG(pisodesc->offset);
  
  				offset += 4;		/* skip past len */
  				if (hdr->caplen < offset)
  					return;
  				pisodesc->len = SWAPLONG(pisodesc->len);
  
  				offset += 4;		/* skip past padding */
  
  				pisodesc++;
  			}
  		}
  	}
  }
  
  /*
   * The DLT_NFLOG "packets" have a mixture of big-endian and host-byte-order
   * data.  They begin with a fixed-length header with big-endian fields,
   * followed by a set of TLVs, where the type and length are in host
   * byte order but the values are either big-endian or are a raw byte
   * sequence that's the same regardless of the host's byte order.
   *
   * When reading a DLT_NFLOG capture file, we need to convert the type
   * and length values from the byte order of the host that wrote the
   * file to the byte order of this host.
   */
  static void
  swap_nflog_header(const struct pcap_pkthdr *hdr, u_char *buf)
  {
  	u_char *p = buf;
  	nflog_hdr_t *nfhdr = (nflog_hdr_t *)buf;
  	nflog_tlv_t *tlv;
  	u_int caplen = hdr->caplen;
  	u_int length = hdr->len;
  	u_int16_t size;
  
  	if (caplen < (int) sizeof(nflog_hdr_t) || length < (int) sizeof(nflog_hdr_t)) {
  		/* Not enough data to have any TLVs. */
  		return;
  	}
  
  	if (nfhdr->nflog_version != 0) {
  		/* Unknown NFLOG version */
  		return;
  	}
  
  	length -= sizeof(nflog_hdr_t);
  	caplen -= sizeof(nflog_hdr_t);
  	p += sizeof(nflog_hdr_t);
  
  	while (caplen >= sizeof(nflog_tlv_t)) {
  		tlv = (nflog_tlv_t *) p;
  
  		/* Swap the type and length. */
  		tlv->tlv_type = SWAPSHORT(tlv->tlv_type);
  		tlv->tlv_length = SWAPSHORT(tlv->tlv_length);
  
  		/* Get the length of the TLV. */
  		size = tlv->tlv_length;
  		if (size % 4 != 0)
  			size += 4 - size % 4;
  
  		/* Is the TLV's length less than the minimum? */
  		if (size < sizeof(nflog_tlv_t)) {
  			/* Yes. Give up now. */
  			return;
  		}
  
  		/* Do we have enough data for the full TLV? */
  		if (caplen < size || length < size) {
  			/* No. */
  			return;
  		}
  
  		/* Skip over the TLV. */
  		length -= size;
  		caplen -= size;
  		p += size;
  	}
  }
  
  void
  swap_pseudo_headers(int linktype, struct pcap_pkthdr *hdr, u_char *data)
  {
  	/*
  	 * Convert pseudo-headers from the byte order of
  	 * the host on which the file was saved to our
  	 * byte order, as necessary.
  	 */
  	switch (linktype) {
  
  	case DLT_USB_LINUX:
  		swap_linux_usb_header(hdr, data, 0);
  		break;
  
  	case DLT_USB_LINUX_MMAPPED:
  		swap_linux_usb_header(hdr, data, 1);
  		break;
  
  	case DLT_NFLOG:
  		swap_nflog_header(hdr, data);
  		break;
  	}
  }
  