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[wireshark-wip.git] / wiretap / pcap-common.c

/* pcap-common.c
 * Code common to libpcap and pcap-NG file formats
 *
 * $Id$
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
 *
 * File format support for pcap-ng file format
 * Copyright (c) 2007 by Ulf Lamping <ulf.lamping@web.de>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "wtap-int.h"
#include "file_wrappers.h"
#include "atm.h"
#include "erf.h"
#include "pcap-encap.h"
#include "pcap-common.h"

/*
 * Map link-layer header types (LINKTYPE_ values) to Wiretap encapsulations.
 *
 * Either LBL NRG wasn't an adequate central registry (e.g., because of
 * the slow rate of releases from them), or nobody bothered using them
 * as a central registry, as many different groups have patched libpcap
 * (and BPF, on the BSDs) to add new encapsulation types, and have ended
 * up using the same DLT_ values for different encapsulation types.
 *
 * The Tcpdump Group now maintains the list of link-layer header types;
 * they introduced a separate namespace of LINKTYPE_ values for the
 * values to be used in capture files, and have libpcap map between
 * those values in capture file headers and the DLT_ values that the
 * pcap_datalink() and pcap_open_dead() APIs use.  See
 * http://www.tcpdump.org/linktypes.html for a list of LINKTYPE_ values.
 *
 * In most cases, the corresponding LINKTYPE_ and DLT_ values are the
 * same.  In the cases where the same link-layer header type was given
 * different values in different OSes, a new LINKTYPE_ value was defined,
 * different from all of the existing DLT_ values.
 *
 * This table maps LINKTYPE_ values to the corresponding Wiretap
 * encapsulation.  For cases where multiple DLT_ values were in use,
 * it also checks what <pcap.h> defineds to determine how to interpret
 * them, so that if a file was written by a version of libpcap prior
 * to the introduction of the LINKTYPE_ values, and has a DLT_ value
 * from the OS on which it was written rather than a LINKTYPE_ value
 * as its linktype value in the file header, we map the numerical
 * DLT_ value, as interpreted by the libpcap with which we're building
 * Wireshark/Wiretap interprets them (which, if it doesn't support
 * them at all, means we don't support them either - any capture files
 * using them are foreign, and we don't hazard a guess as to which
 * platform they came from; we could, I guess, choose the most likely
 * platform), to the corresponding Wiretap encapsulation.
 *
 * Note: if you need a new encapsulation type for libpcap files, do
 * *N*O*T* use *ANY* of the values listed here!  I.e., do *NOT*
 * add a new encapsulation type by changing an existing entry;
 * leave the existing entries alone.
 *
 * Instead, send mail to tcpdump-workers@lists.tcpdump.org, asking for
 * a new LINKTYPE_/DLT_ value, and specifying the purpose of the new
 * value.  When you get the new LINKTYPE_/DLT_ value, use that numerical
 * value in the "linktype_value" field of "pcap_to_wtap_map[]".
 */

static const struct {
        int     linktype_value;
        int     wtap_encap_value;
} pcap_to_wtap_map[] = {
        /*
         * These are the values that are almost certainly the same
         * in all libpcaps (I've yet to find one where the values
         * in question are used for some purpose other than the
         * one below, but...), and thus assigned as LINKTYPE_ values,
         * and that Wiretap and Wireshark currently support.
         */
        { 0,            WTAP_ENCAP_NULL },      /* null encapsulation */
        { 1,            WTAP_ENCAP_ETHERNET },
        { 3,            WTAP_ENCAP_AX25 },
        { 6,            WTAP_ENCAP_TOKEN_RING },        /* IEEE 802 Networks - assume token ring */
        { 7,            WTAP_ENCAP_ARCNET },
        { 8,            WTAP_ENCAP_SLIP },
        { 9,            WTAP_ENCAP_PPP },
#ifdef BIT_SWAPPED_MAC_ADDRS
        { 10,           WTAP_ENCAP_FDDI_BITSWAPPED },
#else
        { 10,           WTAP_ENCAP_FDDI },
#endif

        { 32,           WTAP_ENCAP_REDBACK },

        /*
         * 50 is DLT_PPP_SERIAL in NetBSD; it appears that DLT_PPP
         * on BSD (at least according to standard tcpdump) has, as
         * the first octet, an indication of whether the packet was
         * transmitted or received (rather than having the standard
         * PPP address value of 0xff), but that DLT_PPP_SERIAL puts
         * a real live PPP header there, or perhaps a Cisco PPP header
         * as per section 4.3.1 of RFC 1547 (implementations of this
         * exist in various BSDs in "sys/net/if_spppsubr.c", and
         * I think also exist either in standard Linux or in
         * various Linux patches; the implementations show how to handle
         * Cisco keepalive packets).
         *
         * However, I don't see any obvious place in FreeBSD "if_ppp.c"
         * where anything other than the standard PPP header would be
         * passed up.  I see some stuff that sets the first octet
         * to 0 for incoming and 1 for outgoing packets before applying
         * a BPF filter to see whether to drop packets whose protocol
         * field has the 0x8000 bit set, i.e. network control protocols -
         * those are handed up to userland - but that code puts the
         * address field back before passing the packet up.
         *
         * I also don't see anything immediately obvious that munges
         * the address field for sync PPP, either.
         *
         * Wireshark currently assumes that if the first octet of a
         * PPP frame is 0xFF, it's the address field and is followed
         * by a control field and a 2-byte protocol, otherwise the
         * address and control fields are absent and the frame begins
         * with a protocol field.  If we ever see a BSD/OS PPP
         * capture, we'll have to handle it differently, and we may
         * have to handle standard BSD captures differently if, in fact,
         * they don't have 0xff 0x03 as the first two bytes - but, as per
         * the two paragraphs preceding this, it's not clear that
         * the address field *is* munged into an incoming/outgoing
         * field when the packet is handed to the BPF device.
         *
         * For now, we just map DLT_PPP_SERIAL to WTAP_ENCAP_PPP, as
         * we treat WTAP_ENCAP_PPP packets as if those beginning with
         * 0xff have the standard RFC 1662 "PPP in HDLC-like Framing"
         * 0xff 0x03 address/control header, and DLT_PPP_SERIAL frames
         * appear to contain that unless they're Cisco frames (if we
         * ever see a capture with them, we'd need to implement the
         * RFC 1547 stuff, and the keepalive protocol stuff).
         *
         * We may have to distinguish between "PPP where if it doesn't
         * begin with 0xff there's no HDLC encapsulation and the frame
         * begins with the protocol field" (which is how we handle
         * WTAP_ENCAP_PPP now) and "PPP where there's either HDLC
         * encapsulation or Cisco PPP" (which is what DLT_PPP_SERIAL
         * is) at some point.
         *
         * XXX - NetBSD has DLT_HDLC, which appears to be used for
         * Cisco HDLC.  Ideally, they should use DLT_PPP_SERIAL
         * only for real live HDLC-encapsulated PPP, not for Cisco
         * HDLC.
         */
        { 50,           WTAP_ENCAP_PPP },

        /*
         * Used by NetBSD and OpenBSD pppoe(4).
         */
        { 51,           WTAP_ENCAP_PPP_ETHER },

        /*
         * Apparently used by the Axent Raptor firewall (now Symantec
         * Enterprise Firewall).
         * Thanks, Axent, for not reserving that type with tcpdump.org
         * and not telling anybody about it.
         */
        { 99,           WTAP_ENCAP_SYMANTEC },

        /*
         * These are the values that libpcap 0.5 and later use in
         * capture file headers, in an attempt to work around the
         * confusion decried above, and that Wiretap and Wireshark
         * currently support.  I.e., they're the LINKTYPE_ values
         * for RFC 1483 ATM and "raw IP", respectively, not the
         * DLT_ values for them on all platforms.
         */
        { 100,          WTAP_ENCAP_ATM_RFC1483 },
        { 101,          WTAP_ENCAP_RAW_IP },
#if 0
        /*
         * More values used by libpcap 0.5 as DLT_ values and used by the
         * current CVS version of libpcap in capture file headers.
         * They are not yet handled in Wireshark.
         * If we get a capture that contains them, we'll implement them.
         */
        { 102,          WTAP_ENCAP_SLIP_BSDOS },
        { 103,          WTAP_ENCAP_PPP_BSDOS },
#endif

        /*
         * These ones are handled in Wireshark, though.
         */
        { 104,          WTAP_ENCAP_CHDLC },     /* Cisco HDLC */
        { 105,          WTAP_ENCAP_IEEE_802_11 }, /* IEEE 802.11 */
        { 106,          WTAP_ENCAP_LINUX_ATM_CLIP },
        { 107,          WTAP_ENCAP_FRELAY },    /* Frame Relay */
        { 108,          WTAP_ENCAP_NULL },      /* OpenBSD loopback */
        { 109,          WTAP_ENCAP_ENC },       /* OpenBSD IPSEC enc */
#if 0
        { 110,          WTAP_ENCAP_LANE_802_3 },/* ATM LANE 802.3 */
        { 111,          WTAP_ENCAP_HIPPI },     /* NetBSD HIPPI */
#endif
        { 112,          WTAP_ENCAP_CHDLC },     /* NetBSD HDLC framing */

        /*
         * Linux "cooked mode" captures, used by the current CVS version
         * of libpcap
         * OR
         * it could be a packet in Cisco's ERSPAN encapsulation which uses
         * this number as well (why can't people stick to protocols when it
         * comes to allocating/using DLT types).
         */
        { 113,          WTAP_ENCAP_SLL },       /* Linux cooked capture */

        { 114,          WTAP_ENCAP_LOCALTALK }, /* Localtalk */

        /*
         * The tcpdump.org version of libpcap uses 117, rather than 17,
         * for OpenBSD packet filter logging, so as to avoid conflicting
         * with DLT_LANE8023 in SuSE 6.3 libpcap.
         */
        { 117,          WTAP_ENCAP_PFLOG },

        { 118,          WTAP_ENCAP_CISCO_IOS },
        { 119,          WTAP_ENCAP_IEEE_802_11_PRISM }, /* 802.11 plus Prism monitor mode radio header */
        { 121,          WTAP_ENCAP_HHDLC },     /* HiPath HDLC */
        { 122,          WTAP_ENCAP_IP_OVER_FC },   /* RFC 2625 IP-over-FC */
        { 123,          WTAP_ENCAP_ATM_PDUS },  /* SunATM */
        { 127,          WTAP_ENCAP_IEEE_802_11_RADIOTAP },  /* 802.11 plus radiotap radio header */
        { 128,          WTAP_ENCAP_TZSP },      /* Tazmen Sniffer Protocol */
        { 129,          WTAP_ENCAP_ARCNET_LINUX },
        { 130,          WTAP_ENCAP_JUNIPER_MLPPP }, /* Juniper MLPPP on ML-, LS-, AS- PICs */
        { 131,          WTAP_ENCAP_JUNIPER_MLFR }, /* Juniper MLFR (FRF.15) on ML-, LS-, AS- PICs */
        { 133,          WTAP_ENCAP_JUNIPER_GGSN},
        /*
         * Values 132 and 134 not listed here are reserved for use
         * in Juniper hardware.
         */
        { 135,          WTAP_ENCAP_JUNIPER_ATM2 }, /* various encapsulations captured on the ATM2 PIC */
        { 136,          WTAP_ENCAP_JUNIPER_SVCS }, /* various encapsulations captured on the services PIC */
        { 137,          WTAP_ENCAP_JUNIPER_ATM1 }, /* various encapsulations captured on the ATM1 PIC */

        { 138,          WTAP_ENCAP_APPLE_IP_OVER_IEEE1394 },
                                                /* Apple IP-over-IEEE 1394 */

        { 139,          WTAP_ENCAP_MTP2_WITH_PHDR },
        { 140,          WTAP_ENCAP_MTP2 },
        { 141,          WTAP_ENCAP_MTP3 },
        { 142,          WTAP_ENCAP_SCCP },
        { 143,          WTAP_ENCAP_DOCSIS },
        { 144,          WTAP_ENCAP_IRDA },      /* IrDA capture */

        /* Reserved for private use. */
        { 147,          WTAP_ENCAP_USER0 },
        { 148,          WTAP_ENCAP_USER1 },
        { 149,          WTAP_ENCAP_USER2 },
        { 150,          WTAP_ENCAP_USER3 },
        { 151,          WTAP_ENCAP_USER4 },
        { 152,          WTAP_ENCAP_USER5 },
        { 153,          WTAP_ENCAP_USER6 },
        { 154,          WTAP_ENCAP_USER7 },
        { 155,          WTAP_ENCAP_USER8 },
        { 156,          WTAP_ENCAP_USER9 },
        { 157,          WTAP_ENCAP_USER10 },
        { 158,          WTAP_ENCAP_USER11 },
        { 159,          WTAP_ENCAP_USER12 },
        { 160,          WTAP_ENCAP_USER13 },
        { 161,          WTAP_ENCAP_USER14 },
        { 162,          WTAP_ENCAP_USER15 },

        { 163,          WTAP_ENCAP_IEEE_802_11_AVS },  /* 802.11 plus AVS radio header */

        /*
         * 164 is reserved for Juniper-private chassis-internal
         * meta-information such as QoS profiles, etc..
         */

        { 165,          WTAP_ENCAP_BACNET_MS_TP },

        /*
         * 166 is reserved for a PPP variant in which the first byte
         * of the 0xff03 header, the 0xff, is replaced by a direction
         * byte.  I don't know whether any captures look like that,
         * but it is used for some Linux IP filtering (ipfilter?).
         */

        /* Ethernet PPPoE frames captured on a service PIC */
        { 167,          WTAP_ENCAP_JUNIPER_PPPOE },

        /*
         * 168 is reserved for more Juniper private-chassis-
         * internal meta-information.
         */

        { 169,          WTAP_ENCAP_GPRS_LLC },

        /*
         * 170 and 171 are reserved for ITU-T G.7041/Y.1303 Generic
         * Framing Procedure.
         */

        /* Registered by Gcom, Inc. */
        { 172,          WTAP_ENCAP_GCOM_TIE1 },
        { 173,          WTAP_ENCAP_GCOM_SERIAL },

        { 177,          WTAP_ENCAP_LINUX_LAPD },

        /* Ethernet frames prepended with meta-information */
        { 178,          WTAP_ENCAP_JUNIPER_ETHER },
        /* PPP frames prepended with meta-information */
        { 179,          WTAP_ENCAP_JUNIPER_PPP },
        /* Frame-Relay frames prepended with meta-information */
        { 180,          WTAP_ENCAP_JUNIPER_FRELAY },
        /* C-HDLC frames prepended with meta-information */
        { 181,          WTAP_ENCAP_JUNIPER_CHDLC },
        /* VOIP Frames prepended with meta-information */
        { 183,          WTAP_ENCAP_JUNIPER_VP },
        /* raw USB packets */
        { 186,          WTAP_ENCAP_USB },
        /* Bluetooth HCI UART transport (part H:4) frames, like hcidump */
        { 187,          WTAP_ENCAP_BLUETOOTH_H4 },
        /* IEEE 802.16 MAC Common Part Sublayer */
        { 188,          WTAP_ENCAP_IEEE802_16_MAC_CPS },
        /* USB packets with Linux-specified header */
        { 189,          WTAP_ENCAP_USB_LINUX },
        /* CAN 2.0b frame */
        { 190,          WTAP_ENCAP_CAN20B },
        /* Per-Packet Information header */
        { 192,          WTAP_ENCAP_PPI },
        /* IEEE 802.15.4 Wireless PAN */
        { 195,          WTAP_ENCAP_IEEE802_15_4 },
        /* SITA File Encapsulation */
        { 196,          WTAP_ENCAP_SITA },
        /* Endace Record File Encapsulation */
        { 197,          WTAP_ENCAP_ERF },
        /* IPMB */
        { 199,          WTAP_ENCAP_IPMB },
        /* Bluetooth HCI UART transport (part H:4) frames, like hcidump */
        { 201,          WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR },
        /* AX.25 packet with a 1-byte KISS header */
        { 202,          WTAP_ENCAP_AX25_KISS },
        /* LAPD frame */
        { 203,          WTAP_ENCAP_LAPD },
        /* PPP with pseudoheader */
        { 204,          WTAP_ENCAP_PPP_WITH_PHDR },
        /* IPMB/I2C */
        { 209,          WTAP_ENCAP_I2C },
        /* FlexRay frame */
        { 210,          WTAP_ENCAP_FLEXRAY },
        /* MOST frame */
        { 211,          WTAP_ENCAP_MOST },
        /* LIN frame */
        { 212,          WTAP_ENCAP_LIN },
        /* X2E Xoraya serial frame */
        { 213,          WTAP_ENCAP_X2E_SERIAL },
        /* X2E Xoraya frame */
        { 214,          WTAP_ENCAP_X2E_XORAYA },
        /* IEEE 802.15.4 Wireless PAN non-ASK PHY */
        { 215,          WTAP_ENCAP_IEEE802_15_4_NONASK_PHY },
        /* USB packets with padded Linux-specified header */
        { 220,          WTAP_ENCAP_USB_LINUX_MMAPPED },
        /* Fibre Channel FC-2 frame */
        { 224,          WTAP_ENCAP_FIBRE_CHANNEL_FC2 },
        /* Fibre Channel FC-2 frame with Delimiter */
        { 225,          WTAP_ENCAP_FIBRE_CHANNEL_FC2_WITH_FRAME_DELIMS },
        /* Solaris IPNET */
        { 226,          WTAP_ENCAP_IPNET },
        /* SocketCAN frame */
        { 227,          WTAP_ENCAP_SOCKETCAN },
        /* Raw IPv4 */
        { 228,          WTAP_ENCAP_RAW_IP4 },
        /* Raw IPv6 */
        { 229,          WTAP_ENCAP_RAW_IP6 },
        /* IEEE 802.15.4 Wireless PAN no fcs */
        { 230,          WTAP_ENCAP_IEEE802_15_4_NOFCS },
        /* D-BUS */
        { 231,          WTAP_ENCAP_DBUS },
        /* DVB-CI (Common Interface) */
        { 235,          WTAP_ENCAP_DVBCI },
        /* MUX27010 */
        { 236,          WTAP_ENCAP_MUX27010 },
        /* NFLOG */
        { 239,          WTAP_ENCAP_NFLOG },
        /* netANALYZER pseudo-header followed by Ethernet with CRC */
        { 240,          WTAP_ENCAP_NETANALYZER },
        /* netANALYZER pseudo-header in transparent mode */
        { 241,          WTAP_ENCAP_NETANALYZER_TRANSPARENT },
        /* IP-over-Infiniband, as specified by RFC 4391 section 6 */
        { 242,          WTAP_ENCAP_IP_OVER_IB },
        /* ISO/IEC 13818-1 MPEG2-TS packets */
        { 243,          WTAP_ENCAP_MPEG_2_TS },
        /* NFC LLCP */
        { 245,          WTAP_ENCAP_NFC_LLCP },
        /* SCTP */
        { 248,          WTAP_ENCAP_SCTP},
        /* USBPcap */
        { 249,          WTAP_ENCAP_USBPCAP},
        /* RTAC SERIAL */
        { 250,          WTAP_ENCAP_RTAC_SERIAL},
        /* Bluetooth Low Energy Link Layer */
        { 251,          WTAP_ENCAP_BLUETOOTH_LE_LL},
        /* Wireshark Upper PDU export */
        { 252,          WTAP_ENCAP_WIRESHARK_UPPER_PDU},

        /*
         * To repeat:
         *
         * If you need a new encapsulation type for libpcap files, do
         * *N*O*T* use *ANY* of the values listed here!  I.e., do *NOT*
         * add a new encapsulation type by changing an existing entry;
         * leave the existing entries alone.
         *
         * Instead, send mail to tcpdump-workers@lists.tcpdump.org, asking
         * for a new DLT_ value, and specifying the purpose of the new value.
         * When you get the new DLT_ value, use that numerical value in
         * the "linktype_value" field of "pcap_to_wtap_map[]".
         */

        /*
         * The following are entries for libpcap type values that have
         * different meanings on different OSes.  I.e., these are DLT_
         * values that are different on different OSes, and that have
         * a separate LINKTYPE_ value assigned to them.
         *
         * We put these *after* the entries for the LINKTYPE_ values for
         * those Wiretap encapsulation types, so that, when writing a
         * pcap or pcap-ng file, Wireshark writes the LINKTYPE_ value,
         * not the OS's DLT_ value, as the file's link-layer header type
         * for pcap or the interface's link-layer header type.
         */

        /*
         * 11 is DLT_ATM_RFC1483 on most platforms; the only libpcaps I've
         * seen that define anything other than DLT_ATM_RFC1483 as 11 are
         * the BSD/OS one, which defines DLT_FR as 11, and libpcap 0.5,
         * which define it as 100, mapping the kernel's value to 100, in
         * an attempt to hide the different values used on different
         * platforms.
         *
         * If this is a platform where DLT_FR is defined as 11, we
         * don't handle 11 at all; otherwise, we handle it as
         * DLT_ATM_RFC1483 (this means we'd misinterpret Frame Relay
         * captures from BSD/OS if running on platforms other than BSD/OS,
         * but
         *
         *      1) we don't yet support DLT_FR
         *
         * and
         *
         *      2) nothing short of a heuristic would let us interpret
         *         them correctly).
         */
#if defined(DLT_FR) && (DLT_FR == 11)
        { 11,           WTAP_ENCAP_FRELAY },
#else
        { 11,           WTAP_ENCAP_ATM_RFC1483 },
#endif

        /*
         * 12 is DLT_RAW on most platforms, but it's DLT_C_HDLC on
         * BSD/OS, and DLT_LOOP on OpenBSD.
         *
         * We don't yet handle DLT_C_HDLC, but we can handle DLT_LOOP
         * (it's just like DLT_NULL, only with the AF_ value in network
         * rather than host byte order - Wireshark figures out the
         * byte order from the data, so we don't care what byte order
         * it's in), so if DLT_LOOP is defined as 12, interpret 12
         * as WTAP_ENCAP_NULL, otherwise, unless DLT_C_HDLC is defined
         * as 12, interpret it as WTAP_ENCAP_RAW_IP.
         */
#if defined(DLT_LOOP) && (DLT_LOOP == 12)
        { 12,           WTAP_ENCAP_NULL },
#elif defined(DLT_C_HDLC) && (DLT_C_HDLC == 12)
        /*
         * Put entry for Cisco HDLC here.
         * XXX - is this just WTAP_ENCAP_CHDLC, i.e. does the frame
         * start with a 4-byte Cisco HDLC header?
         */
#else
        { 12,           WTAP_ENCAP_RAW_IP },
#endif

        /*
         * 13 is DLT_SLIP_BSDOS on FreeBSD and NetBSD, but those OSes
         * don't actually generate it.  I infer that BSD/OS translates
         * DLT_SLIP from the kernel BPF code to DLT_SLIP_BSDOS in
         * libpcap, as the BSD/OS link-layer header is different;
         * however, in BSD/OS, DLT_SLIP_BSDOS is 15.
         *
         * From this, I infer that there's no point in handling 13
         * as DLT_SLIP_BSDOS.
         *
         * 13 is DLT_ATM_RFC1483 on BSD/OS.
         *
         * 13 is DLT_ENC in OpenBSD, which is, I suspect, some kind
         * of decrypted IPsec traffic.
         *
         * We treat 13 as WTAP_ENCAP_ENC on all systems except those
         * that define DLT_ATM_RFC1483 as 13 - presumably only
         * BSD/OS does so - so that, on BSD/OS systems, we still
         * treate 13 as WTAP_ENCAP_ATM_RFC1483, but, on all other
         * systems, we can read OpenBSD DLT_ENC captures.
         */
#if defined(DLT_ATM_RFC1483) && (DLT_ATM_RFC1483 == 13)
        { 13,           WTAP_ENCAP_ATM_RFC1483 },
#else
        { 13,           WTAP_ENCAP_ENC },
#endif

        /*
         * 14 is DLT_PPP_BSDOS on FreeBSD and NetBSD, but those OSes
         * don't actually generate it.  I infer that BSD/OS translates
         * DLT_PPP from the kernel BPF code to DLT_PPP_BSDOS in
         * libpcap, as the BSD/OS link-layer header is different;
         * however, in BSD/OS, DLT_PPP_BSDOS is 16.
         *
         * From this, I infer that there's no point in handling 14
         * as DLT_PPP_BSDOS.
         *
         * 14 is DLT_RAW on BSD/OS and OpenBSD.
         */
        { 14,           WTAP_ENCAP_RAW_IP },

        /*
         * 15 is:
         *
         *      DLT_SLIP_BSDOS on BSD/OS;
         *
         *      DLT_HIPPI on NetBSD;
         *
         *      DLT_LANE8023 with Alexey Kuznetzov's patches for
         *      Linux libpcap;
         *
         *      DLT_I4L_RAWIP with the ISDN4Linux patches for libpcap
         *      (and on SuSE 6.3);
         *
         * but we don't currently handle any of those.
         */

        /*
         * 16 is:
         *
         *      DLT_PPP_BSDOS on BSD/OS;
         *
         *      DLT_HDLC on NetBSD (Cisco HDLC);
         *
         *      DLT_CIP with Alexey Kuznetzov's patches for
         *      Linux libpcap - this is WTAP_ENCAP_LINUX_ATM_CLIP;
         *
         *      DLT_I4L_IP with the ISDN4Linux patches for libpcap
         *      (and on SuSE 6.3).
         */
#if defined(DLT_CIP) && (DLT_CIP == 16)
        { 16,           WTAP_ENCAP_LINUX_ATM_CLIP },
#endif
#if defined(DLT_HDLC) && (DLT_HDLC == 16)
        { 16,           WTAP_ENCAP_CHDLC },
#endif

        /*
         * 17 is DLT_LANE8023 in SuSE 6.3 libpcap; we don't currently
         * handle it.
         * It is also used as the PF (Packet Filter) logging format beginning
         * with OpenBSD 3.0; we use 17 for PF logs unless DLT_LANE8023 is
         * defined with the value 17.
         */
#if !defined(DLT_LANE8023) || (DLT_LANE8023 != 17)
        { 17,           WTAP_ENCAP_OLD_PFLOG },
#endif

        /*
         * 18 is DLT_CIP in SuSE 6.3 libpcap; if it's the same as the
         * DLT_CIP of 16 that the Alexey Kuznetzov patches for
         * libpcap/tcpdump define, it's WTAP_ENCAP_LINUX_ATM_CLIP.
         * I've not found any libpcap that uses it for any other purpose -
         * hopefully nobody will do so in the future.
         */
        { 18,           WTAP_ENCAP_LINUX_ATM_CLIP },

        /*
         * 19 is DLT_ATM_CLIP in the libpcap/tcpdump patches in the
         * recent versions I've seen of the Linux ATM distribution;
         * I've not yet found any libpcap that uses it for any other
         * purpose - hopefully nobody will do so in the future.
         */
        { 19,           WTAP_ENCAP_LINUX_ATM_CLIP },

        /*
         * To repeat:
         *
         * If you need a new encapsulation type for libpcap files, do
         * *N*O*T* use *ANY* of the values listed here!  I.e., do *NOT*
         * add a new encapsulation type by changing an existing entry;
         * leave the existing entries alone.
         *
         * Instead, send mail to tcpdump-workers@lists.tcpdump.org, asking
         * for a new DLT_ value, and specifying the purpose of the new value.
         * When you get the new DLT_ value, use that numerical value in
         * the "linktype_value" field of "pcap_to_wtap_map[]".
         */
};
#define NUM_PCAP_ENCAPS (sizeof pcap_to_wtap_map / sizeof pcap_to_wtap_map[0])

int
wtap_pcap_encap_to_wtap_encap(int encap)
{
        unsigned int i;

        for (i = 0; i < NUM_PCAP_ENCAPS; i++) {
                if (pcap_to_wtap_map[i].linktype_value == encap)
                        return pcap_to_wtap_map[i].wtap_encap_value;
        }
        return WTAP_ENCAP_UNKNOWN;
}

int
wtap_wtap_encap_to_pcap_encap(int encap)
{
        unsigned int i;

        switch (encap) {

        case WTAP_ENCAP_FDDI:
        case WTAP_ENCAP_FDDI_BITSWAPPED:
                /*
                 * Special-case WTAP_ENCAP_FDDI and
                 * WTAP_ENCAP_FDDI_BITSWAPPED; both of them get mapped
                 * to DLT_FDDI (even though that may mean that the bit
                 * order in the FDDI MAC addresses is wrong; so it goes
                 * - libpcap format doesn't record the byte order,
                 * so that's not fixable).
                 *
                 * The pcap_to_wtap_map[] table will only have an
                 * entry for one of the above, which is why we have
                 * to special-case them.
                 */
                return 10;      /* that's DLT_FDDI */

        case WTAP_ENCAP_NETTL_FDDI:
                /*
                 * This will discard the nettl information, as that's
                 * in the pseudo-header.
                 *
                 * XXX - what about Ethernet and Token Ring?
                 */
                return 10;      /* that's DLT_FDDI */

        case WTAP_ENCAP_FRELAY_WITH_PHDR:
                /*
                 * This will discard the pseudo-header information.
                 */
                return 107;

        case WTAP_ENCAP_IEEE_802_11_WITH_RADIO:
                /*
                 * Map this to DLT_IEEE802_11, for now, even though
                 * that means the radio information will be lost.
                 * We should try to map those values to radiotap
                 * values and write this out as a radiotap file,
                 * if possible.
                 */
                return 105;
        }

        for (i = 0; i < NUM_PCAP_ENCAPS; i++) {
                if (pcap_to_wtap_map[i].wtap_encap_value == encap)
                        return pcap_to_wtap_map[i].linktype_value;
        }
        return -1;
}

gboolean
wtap_encap_requires_phdr(int encap) {
        if (
                (encap == WTAP_ENCAP_ATM_PDUS) ||
                (encap == WTAP_ENCAP_IRDA) ||
                (encap == WTAP_ENCAP_MTP2_WITH_PHDR) ||
                (encap == WTAP_ENCAP_LINUX_LAPD) ||
                (encap == WTAP_ENCAP_SITA) ||
                (encap == WTAP_ENCAP_ERF) ||
                (encap == WTAP_ENCAP_I2C) ||
                (encap == WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR) ||
                (encap == WTAP_ENCAP_PPP_WITH_PHDR)
        ) {
                return TRUE;
        }
        return FALSE;
}


/*
 * Various pseudo-headers that appear at the beginning of packet data.
 *
 * We represent them as sets of offsets, as they might not be aligned on
 * an appropriate structure boundary in the buffer, and as that makes them
 * independent of the way the compiler might align fields.
 */

/*
 * The link-layer header on SunATM packets.
 */
#define SUNATM_FLAGS    0       /* destination and traffic type - 1 byte */
#define SUNATM_VPI      1       /* VPI - 1 byte */
#define SUNATM_VCI      2       /* VCI - 2 bytes */
#define SUNATM_LEN      4       /* length of the header */

/*
 * The link-layer header on Nokia IPSO ATM packets.
 */
#define NOKIAATM_FLAGS  0       /* destination - 1 byte */
#define NOKIAATM_VPI    1       /* VPI - 1 byte */
#define NOKIAATM_VCI    2       /* VCI - 2 bytes */
#define NOKIAATM_LEN    4       /* length of the header */

/*
 * The link-layer header on Nokia IPSO packets.
 */
#define NOKIA_LEN       4       /* length of the header */

/*
 * The fake link-layer header of IrDA packets as introduced by Jean Tourrilhes
 * to libpcap.
 */
#define IRDA_SLL_PKTTYPE_OFFSET         0       /* packet type - 2 bytes */
/* 12 unused bytes */
#define IRDA_SLL_PROTOCOL_OFFSET        14      /* protocol, should be ETH_P_LAPD - 2 bytes */
#define IRDA_SLL_LEN                    16      /* length of the header */

/*
 * A header containing additional MTP information.
 */
#define MTP2_SENT_OFFSET                0       /* 1 byte */
#define MTP2_ANNEX_A_USED_OFFSET        1       /* 1 byte */
#define MTP2_LINK_NUMBER_OFFSET         2       /* 2 bytes */
#define MTP2_HDR_LEN                    4       /* length of the header */

/*
 * A header containing additional SITA WAN information.
 */
#define SITA_FLAGS_OFFSET               0       /* 1 byte */
#define SITA_SIGNALS_OFFSET             1       /* 1 byte */
#define SITA_ERRORS1_OFFSET             2       /* 1 byte */
#define SITA_ERRORS2_OFFSET             3       /* 1 byte */
#define SITA_PROTO_OFFSET               4       /* 1 byte */
#define SITA_HDR_LEN                    5       /* length of the header */

/*
 * The fake link-layer header of LAPD packets.
 */
#ifndef ETH_P_LAPD
#define ETH_P_LAPD 0x0030
#endif

#define LAPD_SLL_PKTTYPE_OFFSET         0       /* packet type - 2 bytes */
#define LAPD_SLL_HATYPE_OFFSET          2       /* hardware address type - 2 bytes */
#define LAPD_SLL_HALEN_OFFSET           4       /* hardware address length - 2 bytes */
#define LAPD_SLL_ADDR_OFFSET            6       /* address - 8 bytes */
#define LAPD_SLL_PROTOCOL_OFFSET        14      /* protocol, should be ETH_P_LAPD - 2 bytes */
#define LAPD_SLL_LEN                    16      /* length of the header */

/*
 * The NFC LLCP per-packet header.
 */
#define LLCP_ADAPTER_OFFSET             0
#define LLCP_FLAGS_OFFSET               1
#define LLCP_HEADER_LEN                 2

/*
 * I2C link-layer on-disk format
 */
struct i2c_file_hdr {
    guint8 bus;
    guint8 flags[4];
};

static gboolean
pcap_read_sunatm_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        guint8  atm_phdr[SUNATM_LEN];
        int     bytes_read;
        guint8  vpi;
        guint16 vci;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(atm_phdr, SUNATM_LEN, fh);
        if (bytes_read != SUNATM_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        vpi = atm_phdr[SUNATM_VPI];
        vci = pntohs(&atm_phdr[SUNATM_VCI]);

        switch (atm_phdr[SUNATM_FLAGS] & 0x0F) {

        case 0x01:      /* LANE */
                pseudo_header->atm.aal = AAL_5;
                pseudo_header->atm.type = TRAF_LANE;
                break;

        case 0x02:      /* RFC 1483 LLC multiplexed traffic */
                pseudo_header->atm.aal = AAL_5;
                pseudo_header->atm.type = TRAF_LLCMX;
                break;

        case 0x05:      /* ILMI */
                pseudo_header->atm.aal = AAL_5;
                pseudo_header->atm.type = TRAF_ILMI;
                break;

        case 0x06:      /* Q.2931 */
                pseudo_header->atm.aal = AAL_SIGNALLING;
                pseudo_header->atm.type = TRAF_UNKNOWN;
                break;

        case 0x03:      /* MARS (RFC 2022) */
                pseudo_header->atm.aal = AAL_5;
                pseudo_header->atm.type = TRAF_UNKNOWN;
                break;

        case 0x04:      /* IFMP (Ipsilon Flow Management Protocol; see RFC 1954) */
                pseudo_header->atm.aal = AAL_5;
                pseudo_header->atm.type = TRAF_UNKNOWN; /* XXX - TRAF_IPSILON? */
                break;

        default:
                /*
                 * Assume it's AAL5, unless it's VPI 0 and VCI 5, in which
                 * case assume it's AAL_SIGNALLING; we know nothing more
                 * about it.
                 *
                 * XXX - is this necessary?  Or are we guaranteed that
                 * all signalling traffic has a type of 0x06?
                 *
                 * XXX - is this guaranteed to be AAL5?  Or, if the type is
                 * 0x00 ("raw"), might it be non-AAL5 traffic?
                 */
                if (vpi == 0 && vci == 5)
                        pseudo_header->atm.aal = AAL_SIGNALLING;
                else
                        pseudo_header->atm.aal = AAL_5;
                pseudo_header->atm.type = TRAF_UNKNOWN;
                break;
        }
        pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;

        pseudo_header->atm.vpi = vpi;
        pseudo_header->atm.vci = vci;
        pseudo_header->atm.channel = (atm_phdr[SUNATM_FLAGS] & 0x80) ? 0 : 1;

        /* We don't have this information */
        pseudo_header->atm.flags = 0;
        pseudo_header->atm.cells = 0;
        pseudo_header->atm.aal5t_u2u = 0;
        pseudo_header->atm.aal5t_len = 0;
        pseudo_header->atm.aal5t_chksum = 0;

        return TRUE;
}

static gboolean
pcap_read_nokiaatm_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        guint8  atm_phdr[NOKIAATM_LEN];
        int     bytes_read;
        guint8  vpi;
        guint16 vci;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(atm_phdr, NOKIAATM_LEN, fh);
        if (bytes_read != NOKIAATM_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        vpi = atm_phdr[NOKIAATM_VPI];
        vci = pntohs(&atm_phdr[NOKIAATM_VCI]);

        pseudo_header->atm.vpi = vpi;
        pseudo_header->atm.vci = vci;
        pseudo_header->atm.channel = (atm_phdr[NOKIAATM_FLAGS] & 0x80) ? 0 : 1;

        /* We don't have this information */
        pseudo_header->atm.flags = 0;
        pseudo_header->atm.cells = 0;
        pseudo_header->atm.aal5t_u2u = 0;
        pseudo_header->atm.aal5t_len = 0;
        pseudo_header->atm.aal5t_chksum = 0;

        return TRUE;
}

static gboolean
pcap_read_nokia_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        guint8  phdr[NOKIA_LEN];
        int     bytes_read;

        errno = WTAP_ERR_CANT_READ;

        /* backtrack to read the 4 mysterious bytes that aren't considered
        * part of the packet size
        */
        if (file_seek(fh, -NOKIA_LEN, SEEK_CUR, err) == -1)
        {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        bytes_read = file_read(phdr, NOKIA_LEN, fh);
        if (bytes_read != NOKIA_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        memcpy(pseudo_header->nokia.stuff, phdr, NOKIA_LEN);

        return TRUE;
}

static gboolean
pcap_read_irda_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    int *err, gchar **err_info)
{
        guint8  irda_phdr[IRDA_SLL_LEN];
        int     bytes_read;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(irda_phdr, IRDA_SLL_LEN, fh);
        if (bytes_read != IRDA_SLL_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        if (pntohs(&irda_phdr[IRDA_SLL_PROTOCOL_OFFSET]) != 0x0017) {
                *err = WTAP_ERR_BAD_FILE;
                if (err_info != NULL)
                        *err_info = g_strdup("libpcap: IrDA capture has a packet with an invalid sll_protocol field");
                return FALSE;
        }

        pseudo_header->irda.pkttype = pntohs(&irda_phdr[IRDA_SLL_PKTTYPE_OFFSET]);

        return TRUE;
}

static gboolean
pcap_read_mtp2_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        guint8 mtp2_hdr[MTP2_HDR_LEN];
        int    bytes_read;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(mtp2_hdr, MTP2_HDR_LEN, fh);
        if (bytes_read != MTP2_HDR_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        pseudo_header->mtp2.sent         = mtp2_hdr[MTP2_SENT_OFFSET];
        pseudo_header->mtp2.annex_a_used = mtp2_hdr[MTP2_ANNEX_A_USED_OFFSET];
        pseudo_header->mtp2.link_number  = pntohs(&mtp2_hdr[MTP2_LINK_NUMBER_OFFSET]);

        return TRUE;
}

static gboolean
pcap_read_lapd_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    int *err, gchar **err_info)
{
        guint8  lapd_phdr[LAPD_SLL_LEN];
        int     bytes_read;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(lapd_phdr, LAPD_SLL_LEN, fh);
        if (bytes_read != LAPD_SLL_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        if (pntohs(&lapd_phdr[LAPD_SLL_PROTOCOL_OFFSET]) != ETH_P_LAPD) {
                *err = WTAP_ERR_BAD_FILE;
                if (err_info != NULL)
                        *err_info = g_strdup("libpcap: LAPD capture has a packet with an invalid sll_protocol field");
                return FALSE;
        }

        pseudo_header->lapd.pkttype = pntohs(&lapd_phdr[LAPD_SLL_PKTTYPE_OFFSET]);
        pseudo_header->lapd.we_network = !!lapd_phdr[LAPD_SLL_ADDR_OFFSET+0];

        return TRUE;
}

static gboolean
pcap_read_sita_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        guint8  sita_phdr[SITA_HDR_LEN];
        int     bytes_read;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(sita_phdr, SITA_HDR_LEN, fh);
        if (bytes_read != SITA_HDR_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        pseudo_header->sita.sita_flags   = sita_phdr[SITA_FLAGS_OFFSET];
        pseudo_header->sita.sita_signals = sita_phdr[SITA_SIGNALS_OFFSET];
        pseudo_header->sita.sita_errors1 = sita_phdr[SITA_ERRORS1_OFFSET];
        pseudo_header->sita.sita_errors2 = sita_phdr[SITA_ERRORS2_OFFSET];
        pseudo_header->sita.sita_proto   = sita_phdr[SITA_PROTO_OFFSET];

        return TRUE;
}

/*
 * When not using the memory-mapped interface to capture USB events,
 * code that reads those events can use the MON_IOCX_GET ioctl to
 * read a 48-byte header consisting of a "struct linux_usb_phdr", as
 * defined below, followed immediately by one of:
 *
 *      8 bytes of a "struct usb_device_setup_hdr", if "setup_flag"
 *      in the preceding "struct linux_usb_phdr" is 0;
 *
 *      in Linux 2.6.30 or later, 8 bytes of a "struct iso_rec", if
 *      this is an isochronous transfer;
 *
 *      8 bytes of junk, otherwise.
 *
 * In Linux 2.6.31 and later, it can also use the MON_IOCX_GETX ioctl
 * to read a 64-byte header; that header consists of the 48 bytes
 * above, followed immediately by 16 bytes of a "struct linux_usb_phdr_ext",
 * as defined below.
 *
 * In Linux 2.6.21 and later, there's a memory-mapped interface to
 * capture USB events.  In that interface, the events in the memory-mapped
 * buffer have a 64-byte header, followed immediately by the data.
 * In Linux 2.6.21 through 2.6.30.x, the 64-byte header is the 48-byte
 * header described above, followed by 16 bytes of zeroes; in Linux
 * 2.6.31 and later, the 64-byte header is the 64-byte header described
 * above.
 *
 * See linux/Documentation/usb/usbmon.txt and libpcap/pcap/usb.h for details.
 *
 * With WTAP_ENCAP_USB_LINUX, packets have the 48-byte header; with
 * WTAP_ENCAP_USB_LINUX_MMAPPED, they have the 64-byte header.  There
 * is no indication of whether the header has the "struct iso_rec", or
 * whether the last 16 bytes of a 64-byte header are all zeros or are
 * a "struct linux_usb_phdr_ext".
 */

/*
 * URB transfer_type values
 */
#define URB_ISOCHRONOUS   0x0
#define URB_INTERRUPT     0x1
#define URB_CONTROL       0x2
#define URB_BULK          0x3

/*
 * Information from the URB for Isochronous transfers.
 *
 * This structure is 8 bytes long.
 */
struct iso_rec {
    gint32 error_count;
    gint32 numdesc;
};

/*
 * Header prepended by Linux kernel to each USB event.
 *
 * (Setup flag is '-', 'D', 'Z', or 0.  Data flag is '<', '>', 'Z', or 0.)
 *
 * The values are in *host* byte order.
 */
struct linux_usb_phdr {
    guint64 id;             /* urb id, to link submission and completion events */
    guint8 event_type;      /* Submit ('S'), Completed ('C'), Error ('E') */
    guint8 transfer_type;   /* ISO (0), Intr, Control, Bulk (3) */
    guint8 endpoint_number; /* Endpoint number (0-15) and transfer direction */
    guint8 device_address;  /* 0-127 */
    guint16 bus_id;
    gint8 setup_flag;       /* 0, if the urb setup header is meaningful */
    gint8 data_flag;        /* 0, if urb data is present */
    gint64 ts_sec;
    gint32 ts_usec;
    gint32 status;
    guint32 urb_len;        /* whole len of urb this event refers to */
    guint32 data_len;       /* amount of urb data really present in this event */

    /*
     * Packet-type-dependent data.
     * USB setup information of setup_flag is true.
     * Otherwise, some isochronous transfer information.
     */
    union {
        guint8 data[8];
        struct iso_rec iso;
    } s;

    /*
     * This data is provided by Linux 2.6.31 and later kernels.
     *
     * For WTAP_ENCAP_USB_LINUX, it's not in the pseudo-header, so
     * the pseudo-header is always 48 bytes long, including the
     * packet-type-dependent data.
     *
     * For WTAP_ENCAP_USB_LINUX_MMAPPED, the pseudo-header is always
     * 64 bytes long, with the packet-type-dependent data preceding
     * these last 16 bytes.  In pre-2.6.31 kernels, it's zero padding;
     * in 2.6.31 and later, it's the following data.
     */
    gint32 interval;    /* only for Interrupt and Isochronous events */
    gint32 start_frame; /* for Isochronous */
    guint32 xfer_flags; /* copy of URB's transfer_flags */
    guint32 ndesc;      /* actual number of isochronous descriptors */
};

struct linux_usb_isodesc {
    gint32 iso_status;
    guint32 iso_off;
    guint32 iso_len;
    guint32 _pad;
};

/*
 * USB setup header as defined in USB specification
 * See usb_20.pdf, Chapter 9.3 'USB Device Requests' for details.
 * http://www.usb.org/developers/docs/usb_20_122909-2.zip
 *
 * This structure is 8 bytes long.
 */
struct usb_device_setup_hdr {
    gint8 bmRequestType;
    guint8 bRequest;
    guint16 wValue;
    guint16 wIndex;
    guint16 wLength;
};


/*
 * Offset of the *end* of a field within a particular structure.
 */
#define END_OFFSETOF(basep, fieldp) \
        (((char *)(void *)(fieldp)) - ((char *)(void *)(basep)) + \
            sizeof(*fieldp))

static void
pcap_process_linux_usb_pseudoheader(guint packet_size, gboolean byte_swapped,
    gboolean header_len_64_bytes, guint8 *pd)
{
        struct linux_usb_phdr *phdr;
        struct linux_usb_isodesc *pisodesc;
        gint32 iso_numdesc, i;

        if (byte_swapped) {
                /*
                 * Greasy hack, but we never directly direference any of
                 * the fields in *phdr, we just get offsets of and
                 * addresses of its members, so it's safe.
                 */
                phdr = (struct linux_usb_phdr *)(void *)pd;

                if (packet_size < END_OFFSETOF(phdr, &phdr->id))
                        return;
                PBSWAP64((guint8 *)&phdr->id);
                if (packet_size < END_OFFSETOF(phdr, &phdr->bus_id))
                        return;
                PBSWAP16((guint8 *)&phdr->bus_id);
                if (packet_size < END_OFFSETOF(phdr, &phdr->ts_sec))
                        return;
                PBSWAP64((guint8 *)&phdr->ts_sec);
                if (packet_size < END_OFFSETOF(phdr, &phdr->ts_usec))
                        return;
                PBSWAP32((guint8 *)&phdr->ts_usec);
                if (packet_size < END_OFFSETOF(phdr, &phdr->status))
                        return;
                PBSWAP32((guint8 *)&phdr->status);
                if (packet_size < END_OFFSETOF(phdr, &phdr->urb_len))
                        return;
                PBSWAP32((guint8 *)&phdr->urb_len);
                if (packet_size < END_OFFSETOF(phdr, &phdr->data_len))
                        return;
                PBSWAP32((guint8 *)&phdr->data_len);

                if (phdr->transfer_type == URB_ISOCHRONOUS) {
                        if (packet_size < END_OFFSETOF(phdr, &phdr->s.iso.error_count))
                                return;
                        PBSWAP32((guint8 *)&phdr->s.iso.error_count);

                        if (packet_size < END_OFFSETOF(phdr, &phdr->s.iso.numdesc))
                                return;
                        PBSWAP32((guint8 *)&phdr->s.iso.numdesc);

                }

                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.
                         *
                         * Yes, the first argument to END_OFFSETOF() should
                         * be phdr, not phdr_ext; we want the offset of
                         * the additional fields from the beginning of
                         * the packet.
                         */
                        if (packet_size < END_OFFSETOF(phdr, &phdr->interval))
                                return;
                        PBSWAP32((guint8 *)&phdr->interval);
                        if (packet_size < END_OFFSETOF(phdr, &phdr->start_frame))
                                return;
                        PBSWAP32((guint8 *)&phdr->start_frame);
                        if (packet_size < END_OFFSETOF(phdr, &phdr->xfer_flags))
                                return;
                        PBSWAP32((guint8 *)&phdr->xfer_flags);
                        if (packet_size < END_OFFSETOF(phdr, &phdr->ndesc))
                                return;
                        PBSWAP32((guint8 *)&phdr->ndesc);
                }

                if (phdr->transfer_type == URB_ISOCHRONOUS) {
                        /* swap the values in struct linux_usb_isodesc */

                        /*
                         * See previous "Greasy hack" comment.
                         */
                        if (header_len_64_bytes) {
                                pisodesc = (struct linux_usb_isodesc*)(void *)(pd + 64);
                        } else {
                                pisodesc = (struct linux_usb_isodesc*)(void *)(pd + 48);
                        }
                        iso_numdesc = phdr->s.iso.numdesc;
                        for (i = 0; i < iso_numdesc; i++) {
                                /* always check if we have enough data from the
                                 * beginnig of the packet (phdr)
                                 */
                                if (packet_size < END_OFFSETOF(phdr, &pisodesc->iso_status))
                                        return;
                                PBSWAP32((guint8 *)&pisodesc->iso_status);
                                if (packet_size < END_OFFSETOF(phdr, &pisodesc->iso_off))
                                        return;
                                PBSWAP32((guint8 *)&pisodesc->iso_off);
                                if (packet_size < END_OFFSETOF(phdr, &pisodesc->iso_len))
                                        return;
                                PBSWAP32((guint8 *)&pisodesc->iso_len);
                                if (packet_size < END_OFFSETOF(phdr, &pisodesc->_pad))
                                        return;
                                PBSWAP32((guint8 *)&pisodesc->_pad);

                                pisodesc++;
                        }
                }
        }
}

static gboolean
pcap_read_bt_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        int     bytes_read;
        struct libpcap_bt_phdr phdr;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(&phdr,
            sizeof (struct libpcap_bt_phdr), fh);
        if (bytes_read != sizeof (struct libpcap_bt_phdr)) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }
        pseudo_header->p2p.sent = ((g_ntohl(phdr.direction) & LIBPCAP_BT_PHDR_RECV) == 0)? TRUE: FALSE;
        return TRUE;
}

static gboolean
pcap_read_llcp_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        int bytes_read;
        guint8 phdr[LLCP_HEADER_LEN];

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(phdr, LLCP_HEADER_LEN, fh);
        if (bytes_read != LLCP_HEADER_LEN) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }
        pseudo_header->llcp.adapter = phdr[LLCP_ADAPTER_OFFSET];
        pseudo_header->llcp.flags = phdr[LLCP_FLAGS_OFFSET];
        return TRUE;
}

static gboolean
pcap_read_ppp_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        int     bytes_read;
        struct libpcap_ppp_phdr phdr;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(&phdr,
            sizeof (struct libpcap_ppp_phdr), fh);
        if (bytes_read != sizeof (struct libpcap_ppp_phdr)) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }
        pseudo_header->p2p.sent = (phdr.direction == LIBPCAP_PPP_PHDR_SENT) ? TRUE: FALSE;
        return TRUE;
}

static gboolean
pcap_read_erf_pseudoheader(FILE_T fh, struct wtap_pkthdr *whdr,
                              union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
  guint8 erf_hdr[sizeof(struct erf_phdr)];
  int    bytes_read;

  errno = WTAP_ERR_CANT_READ;
  bytes_read = file_read(erf_hdr, sizeof(struct erf_phdr), fh);
  if (bytes_read != sizeof(struct erf_phdr)) {
    *err = file_error(fh, err_info);
    if (*err == 0)
      *err = WTAP_ERR_SHORT_READ;
    return FALSE;
  }
  pseudo_header->erf.phdr.ts = pletohll(&erf_hdr[0]); /* timestamp */
  pseudo_header->erf.phdr.type =  erf_hdr[8];
  pseudo_header->erf.phdr.flags = erf_hdr[9];
  pseudo_header->erf.phdr.rlen = pntohs(&erf_hdr[10]);
  pseudo_header->erf.phdr.lctr = pntohs(&erf_hdr[12]);
  pseudo_header->erf.phdr.wlen = pntohs(&erf_hdr[14]);

  /* The high 32 bits of the timestamp contain the integer number of seconds
   * while the lower 32 bits contain the binary fraction of the second.
   * This allows an ultimate resolution of 1/(2^32) seconds, or approximately 233 picoseconds */
  if (whdr) {
    guint64 ts = pseudo_header->erf.phdr.ts;
    whdr->ts.secs = (guint32) (ts >> 32);
    ts = ((ts & 0xffffffff) * 1000 * 1000 * 1000);
    ts += (ts & 0x80000000) << 1; /* rounding */
    whdr->ts.nsecs = ((guint32) (ts >> 32));
    if ( whdr->ts.nsecs >= 1000000000) {
      whdr->ts.nsecs -= 1000000000;
      whdr->ts.secs += 1;
    }
  }
  return TRUE;
}

/*
 * If the type of record given in the pseudo header indicate the presence of an extension
 * header then, read all the extension headers
 */
static gboolean
pcap_read_erf_exheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
                           int *err, gchar **err_info, guint * psize)
{
  int bytes_read = 0;
  guint8 erf_exhdr[8];
  guint64 erf_exhdr_sw;
  int i = 0, max = sizeof(pseudo_header->erf.ehdr_list)/sizeof(struct erf_ehdr);
  guint8 type;
  *psize = 0;
  if (pseudo_header->erf.phdr.type & 0x80){
    do{
      errno = WTAP_ERR_CANT_READ;
      bytes_read = file_read(erf_exhdr, 8, fh);
      if (bytes_read != 8 ) {
        *err = file_error(fh, err_info);
        if (*err == 0)
          *err = WTAP_ERR_SHORT_READ;
        return FALSE;
      }
      type = erf_exhdr[0];
      erf_exhdr_sw = pntohll(erf_exhdr);
      if (i < max)
        memcpy(&pseudo_header->erf.ehdr_list[i].ehdr, &erf_exhdr_sw, sizeof(erf_exhdr_sw));
      *psize += 8;
      i++;
    } while (type & 0x80);
  }
  return TRUE;
}

/*
 * If the type of record given in the pseudo header indicate the precense of a subheader
 * then, read this optional subheader
 */
static gboolean
pcap_read_erf_subheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
                           int *err, gchar **err_info, guint * psize)
{
  guint8 erf_subhdr[sizeof(union erf_subhdr)];
  int    bytes_read;

  *psize=0;
  switch(pseudo_header->erf.phdr.type & 0x7F) {
  case ERF_TYPE_MC_HDLC:
  case ERF_TYPE_MC_RAW:
  case ERF_TYPE_MC_ATM:
  case ERF_TYPE_MC_RAW_CHANNEL:
  case ERF_TYPE_MC_AAL5:
  case ERF_TYPE_MC_AAL2:
  case ERF_TYPE_COLOR_MC_HDLC_POS:
    /* Extract the Multi Channel header to include it in the pseudo header part */
    errno = WTAP_ERR_CANT_READ;
    bytes_read = file_read(erf_subhdr, sizeof(erf_mc_header_t), fh);
    if (bytes_read != sizeof(erf_mc_header_t) ) {
      *err = file_error(fh, err_info);
      if (*err == 0)
        *err = WTAP_ERR_SHORT_READ;
      return FALSE;
    }
    pseudo_header->erf.subhdr.mc_hdr = pntohl(&erf_subhdr[0]);
    *psize = sizeof(erf_mc_header_t);
    break;
  case ERF_TYPE_ETH:
  case ERF_TYPE_COLOR_ETH:
  case ERF_TYPE_DSM_COLOR_ETH:
    /* Extract the Ethernet additional header to include it in the pseudo header part */
    errno = WTAP_ERR_CANT_READ;
    bytes_read = file_read(erf_subhdr, sizeof(erf_eth_header_t), fh);
    if (bytes_read != sizeof(erf_eth_header_t) ) {
      *err = file_error(fh, err_info);
      if (*err == 0)
        *err = WTAP_ERR_SHORT_READ;
      return FALSE;
    }
    pseudo_header->erf.subhdr.eth_hdr = pntohs(&erf_subhdr[0]);
    *psize = sizeof(erf_eth_header_t);
    break;
  default:
    /* No optional pseudo header for this ERF type */
    break;
  }
  return TRUE;
}

static gboolean
pcap_read_i2c_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
{
        struct i2c_file_hdr i2c_hdr;
        int    bytes_read;

        errno = WTAP_ERR_CANT_READ;
        bytes_read = file_read(&i2c_hdr, sizeof (i2c_hdr), fh);
        if (bytes_read != sizeof (i2c_hdr)) {
                *err = file_error(fh, err_info);
                if (*err == 0)
                        *err = WTAP_ERR_SHORT_READ;
                return FALSE;
        }

        pseudo_header->i2c.is_event = i2c_hdr.bus & 0x80 ? 1 : 0;
        pseudo_header->i2c.bus = i2c_hdr.bus & 0x7f;
        pseudo_header->i2c.flags = pntohl(&i2c_hdr.flags);

        return TRUE;
}

int
pcap_process_pseudo_header(FILE_T fh, int file_type, int wtap_encap,
    guint packet_size, gboolean check_packet_size,
    struct wtap_pkthdr *phdr, int *err, gchar **err_info)
{
        int phdr_len = 0;
        guint size;

        switch (wtap_encap) {

        case WTAP_ENCAP_ATM_PDUS:
                if (file_type == WTAP_FILE_TYPE_SUBTYPE_PCAP_NOKIA) {
                        /*
                         * Nokia IPSO ATM.
                         */
                        if (check_packet_size && packet_size < NOKIAATM_LEN) {
                                /*
                                 * Uh-oh, the packet isn't big enough to even
                                 * have a pseudo-header.
                                 */
                                *err = WTAP_ERR_BAD_FILE;
                                *err_info = g_strdup_printf("pcap: Nokia IPSO ATM file has a %u-byte packet, too small to have even an ATM pseudo-header",
                                    packet_size);
                                return -1;
                        }
                        if (!pcap_read_nokiaatm_pseudoheader(fh,
                            &phdr->pseudo_header, err, err_info))
                                return -1;      /* Read error */

                        phdr_len = NOKIAATM_LEN;
                } else {
                        /*
                         * SunATM.
                         */
                        if (check_packet_size && packet_size < SUNATM_LEN) {
                                /*
                                 * Uh-oh, the packet isn't big enough to even
                                 * have a pseudo-header.
                                 */
                                *err = WTAP_ERR_BAD_FILE;
                                *err_info = g_strdup_printf("pcap: SunATM file has a %u-byte packet, too small to have even an ATM pseudo-header",
                                    packet_size);
                                return -1;
                        }
                        if (!pcap_read_sunatm_pseudoheader(fh,
                            &phdr->pseudo_header, err, err_info))
                                return -1;      /* Read error */

                        phdr_len = SUNATM_LEN;
                }
                break;

        case WTAP_ENCAP_ETHERNET:
                if (file_type == WTAP_FILE_TYPE_SUBTYPE_PCAP_NOKIA) {
                        /*
                         * Nokia IPSO.  Psuedo header has already been read, but it's not considered
                         * part of the packet size, so reread it to store the data for later (when saving)
                         */
                        if (!pcap_read_nokia_pseudoheader(fh, &phdr->pseudo_header, err, err_info))
                                return -1;      /* Read error */
                }

                /*
                 * We don't know whether there's an FCS in this frame or not.
                 */
                phdr->pseudo_header.eth.fcs_len = -1;
                break;

        case WTAP_ENCAP_IEEE_802_11:
        case WTAP_ENCAP_IEEE_802_11_PRISM:
        case WTAP_ENCAP_IEEE_802_11_RADIOTAP:
        case WTAP_ENCAP_IEEE_802_11_AVS:
                /*
                 * We don't know whether there's an FCS in this frame or not.
                 * XXX - are there any OSes where the capture mechanism
                 * supplies an FCS?
                 */
                phdr->pseudo_header.ieee_802_11.fcs_len = -1;
                phdr->pseudo_header.ieee_802_11.decrypted = FALSE;
                phdr->pseudo_header.ieee_802_11.channel = 0;
                phdr->pseudo_header.ieee_802_11.data_rate = 0;
                phdr->pseudo_header.ieee_802_11.signal_level = 0;
                break;

        case WTAP_ENCAP_IRDA:
                if (check_packet_size && packet_size < IRDA_SLL_LEN) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: IrDA file has a %u-byte packet, too small to have even an IrDA pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_irda_pseudoheader(fh, &phdr->pseudo_header,
                    err, err_info))
                        return -1;      /* Read error */

                phdr_len = IRDA_SLL_LEN;
                break;

        case WTAP_ENCAP_MTP2_WITH_PHDR:
                if (check_packet_size && packet_size < MTP2_HDR_LEN) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: MTP2 file has a %u-byte packet, too small to have even an MTP2 pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_mtp2_pseudoheader(fh, &phdr->pseudo_header,
                    err, err_info))
                        return -1;      /* Read error */

                phdr_len = MTP2_HDR_LEN;
                break;

        case WTAP_ENCAP_LINUX_LAPD:
                if (check_packet_size && packet_size < LAPD_SLL_LEN) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: LAPD file has a %u-byte packet, too small to have even a LAPD pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_lapd_pseudoheader(fh, &phdr->pseudo_header,
                    err, err_info))
                        return -1;      /* Read error */

                phdr_len = LAPD_SLL_LEN;
                break;

        case WTAP_ENCAP_SITA:
                if (check_packet_size && packet_size < SITA_HDR_LEN) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: SITA file has a %u-byte packet, too small to have even a SITA pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_sita_pseudoheader(fh, &phdr->pseudo_header,
                    err, err_info))
                        return -1;      /* Read error */

                phdr_len = SITA_HDR_LEN;
                break;

        case WTAP_ENCAP_BLUETOOTH_H4:
                /* We don't have pseudoheader, so just pretend we received everything. */
                phdr->pseudo_header.p2p.sent = FALSE;
                break;

        case WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR:
                if (check_packet_size &&
                    packet_size < sizeof (struct libpcap_bt_phdr)) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: libpcap bluetooth file has a %u-byte packet, too small to have even a pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_bt_pseudoheader(fh,
                    &phdr->pseudo_header, err, err_info))
                        return -1;      /* Read error */

                phdr_len = (int)sizeof (struct libpcap_bt_phdr);
                break;

        case WTAP_ENCAP_NFC_LLCP:
                if (check_packet_size && packet_size < LLCP_HEADER_LEN) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: libpcap llcp file too short");
                        return -1;
                }
                if (!pcap_read_llcp_pseudoheader(fh, &phdr->pseudo_header, err, err_info))
                        return -1;      /* Read error */
                phdr_len = LLCP_HEADER_LEN;
                break;

        case WTAP_ENCAP_PPP_WITH_PHDR:
                if (check_packet_size &&
                    packet_size < sizeof (struct libpcap_ppp_phdr)) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: libpcap ppp file has a %u-byte packet, too small to have even a pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_ppp_pseudoheader(fh,
                    &phdr->pseudo_header, err, err_info))
                        return -1;      /* Read error */

                phdr_len = (int)sizeof (struct libpcap_ppp_phdr);
                break;

        case WTAP_ENCAP_ERF:
                if (check_packet_size &&
                    packet_size < sizeof(struct erf_phdr) ) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: ERF file has a %u-byte packet, too small to have even an ERF pseudo-header",
                            packet_size);
                        return -1;
                }

                if (!pcap_read_erf_pseudoheader(fh, phdr, &phdr->pseudo_header,
                    err, err_info))
                        return -1;      /* Read error */

                phdr_len = (int)sizeof(struct erf_phdr);

                /* check the optional Extension header */
                if (!pcap_read_erf_exheader(fh, &phdr->pseudo_header, err, err_info,
                    &size))
                        return -1;      /* Read error */

                phdr_len += size;

                /* check the optional Multi Channel header */
                if (!pcap_read_erf_subheader(fh, &phdr->pseudo_header, err, err_info,
                    &size))
                        return -1;      /* Read error */

                phdr_len += size;

                if (check_packet_size &&
                    packet_size < (guint)phdr_len) {
                        /*
                         * Uh-oh, the packet isn't big enough for the pseudo-
                         * header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: ERF file has a %u-byte packet, too small for a pseudo-header with ex- and sub-headers (%d)",
                            packet_size, phdr_len);
                        return -1;
                }
                break;

        case WTAP_ENCAP_I2C:
                if (check_packet_size &&
                    packet_size < sizeof (struct i2c_file_hdr)) {
                        /*
                         * Uh-oh, the packet isn't big enough to even
                         * have a pseudo-header.
                         */
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = g_strdup_printf("pcap: I2C file has a %u-byte packet, too small to have even a I2C pseudo-header",
                            packet_size);
                        return -1;
                }
                if (!pcap_read_i2c_pseudoheader(fh, &phdr->pseudo_header,
                    err, err_info))
                        return -1;      /* Read error */

                /*
                 * Don't count the pseudo-header as part of the packet.
                 */
                phdr_len = (int)sizeof (struct i2c_file_hdr);
                break;
        }

        return phdr_len;
}

void
pcap_read_post_process(int file_type, int wtap_encap,
    union wtap_pseudo_header *pseudo_header,
    guint8 *pd, guint packet_size, gboolean bytes_swapped, int fcs_len)
{
        switch (wtap_encap) {

        case WTAP_ENCAP_ATM_PDUS:
                if (file_type == WTAP_FILE_TYPE_SUBTYPE_PCAP_NOKIA) {
                        /*
                         * Nokia IPSO ATM.
                         *
                         * Guess the traffic type based on the packet
                         * contents.
                         */
                        atm_guess_traffic_type(pd, packet_size, pseudo_header);
                } else {
                        /*
                         * SunATM.
                         *
                         * If this is ATM LANE traffic, try to guess what
                         * type of LANE traffic it is based on the packet
                         * contents.
                         */
                        if (pseudo_header->atm.type == TRAF_LANE)
                                atm_guess_lane_type(pd, packet_size,
                                    pseudo_header);
                }
                break;

        case WTAP_ENCAP_ETHERNET:
                pseudo_header->eth.fcs_len = fcs_len;
                break;

        case WTAP_ENCAP_USB_LINUX:
                pcap_process_linux_usb_pseudoheader(packet_size,
                    bytes_swapped, FALSE, pd);
                break;

        case WTAP_ENCAP_USB_LINUX_MMAPPED:
                pcap_process_linux_usb_pseudoheader(packet_size,
                    bytes_swapped, TRUE, pd);
                break;

        case WTAP_ENCAP_NETANALYZER:
                /*
                 * Not strictly necessary, as the netANALYZER
                 * dissector calls the "Ethernet with FCS"
                 * dissector, but we might as well set it.
                 */
                pseudo_header->eth.fcs_len = 4;
                break;

        default:
                break;
        }
}

int
pcap_get_phdr_size(int encap, const union wtap_pseudo_header *pseudo_header)
{
        int hdrsize;

        switch (encap) {

        case WTAP_ENCAP_ATM_PDUS:
                hdrsize = SUNATM_LEN;
                break;

        case WTAP_ENCAP_IRDA:
                hdrsize = IRDA_SLL_LEN;
                break;

        case WTAP_ENCAP_MTP2_WITH_PHDR:
                hdrsize = MTP2_HDR_LEN;
                break;

        case WTAP_ENCAP_LINUX_LAPD:
                hdrsize = LAPD_SLL_LEN;
                break;

        case WTAP_ENCAP_SITA:
                hdrsize = SITA_HDR_LEN;
                break;

        case WTAP_ENCAP_ERF:
                hdrsize = (int)sizeof (struct erf_phdr);
                switch (pseudo_header->erf.phdr.type & 0x7F) {

                case ERF_TYPE_MC_HDLC:
                case ERF_TYPE_MC_RAW:
                case ERF_TYPE_MC_ATM:
                case ERF_TYPE_MC_RAW_CHANNEL:
                case ERF_TYPE_MC_AAL5:
                case ERF_TYPE_MC_AAL2:
                case ERF_TYPE_COLOR_MC_HDLC_POS:
                        hdrsize += (int)sizeof(struct erf_mc_hdr);
                        break;

                case ERF_TYPE_ETH:
                case ERF_TYPE_COLOR_ETH:
                case ERF_TYPE_DSM_COLOR_ETH:
                        hdrsize += (int)sizeof(struct erf_eth_hdr);
                        break;

                default:
                        break;
                }

                /*
                 * Add in the lengths of the extension headers.
                 */
                if (pseudo_header->erf.phdr.type & 0x80) {
                        int i = 0, max = sizeof(pseudo_header->erf.ehdr_list)/sizeof(struct erf_ehdr);
                        guint8 erf_exhdr[8];
                        guint8 type;

                        do {
                                phtonll(erf_exhdr, pseudo_header->erf.ehdr_list[i].ehdr);
                                type = erf_exhdr[0];
                                hdrsize += 8;
                                i++;
                        } while (type & 0x80 && i < max);
                }
                break;

        case WTAP_ENCAP_I2C:
                hdrsize = (int)sizeof (struct i2c_file_hdr);
                break;

        case WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR:
                hdrsize = (int)sizeof (struct libpcap_bt_phdr);
                break;

        case WTAP_ENCAP_PPP_WITH_PHDR:
                hdrsize = (int)sizeof (struct libpcap_ppp_phdr);
                break;

        default:
                hdrsize = 0;
                break;
        }

        return hdrsize;
}

gboolean
pcap_write_phdr(wtap_dumper *wdh, int encap, const union wtap_pseudo_header *pseudo_header,
    int *err)
{
        guint8 atm_hdr[SUNATM_LEN];
        guint8 irda_hdr[IRDA_SLL_LEN];
        guint8 lapd_hdr[LAPD_SLL_LEN];
        guint8 mtp2_hdr[MTP2_HDR_LEN];
        guint8 sita_hdr[SITA_HDR_LEN];
        guint8 erf_hdr[ sizeof(struct erf_mc_phdr)];
        struct i2c_file_hdr i2c_hdr;
        struct libpcap_bt_phdr bt_hdr;
        struct libpcap_ppp_phdr ppp_hdr;
        size_t size;

        switch (encap) {

        case WTAP_ENCAP_ATM_PDUS:
                /*
                 * Write the ATM header.
                 */
                atm_hdr[SUNATM_FLAGS] =
                    (pseudo_header->atm.channel == 0) ? 0x80 : 0x00;
                switch (pseudo_header->atm.aal) {

                case AAL_SIGNALLING:
                        /* Q.2931 */
                        atm_hdr[SUNATM_FLAGS] |= 0x06;
                        break;

                case AAL_5:
                        switch (pseudo_header->atm.type) {

                        case TRAF_LANE:
                                /* LANE */
                                atm_hdr[SUNATM_FLAGS] |= 0x01;
                                break;

                        case TRAF_LLCMX:
                                /* RFC 1483 LLC multiplexed traffic */
                                atm_hdr[SUNATM_FLAGS] |= 0x02;
                                break;

                        case TRAF_ILMI:
                                /* ILMI */
                                atm_hdr[SUNATM_FLAGS] |= 0x05;
                                break;
                        }
                        break;
                }
                atm_hdr[SUNATM_VPI] = (guint8)pseudo_header->atm.vpi;
                phtons(&atm_hdr[SUNATM_VCI], pseudo_header->atm.vci);
                if (!wtap_dump_file_write(wdh, atm_hdr, sizeof(atm_hdr), err))
                        return FALSE;
                wdh->bytes_dumped += sizeof(atm_hdr);
                break;

        case WTAP_ENCAP_IRDA:
                /*
                 * Write the IrDA header.
                 */
                memset(irda_hdr, 0, sizeof(irda_hdr));
                phtons(&irda_hdr[IRDA_SLL_PKTTYPE_OFFSET],
                    pseudo_header->irda.pkttype);
                phtons(&irda_hdr[IRDA_SLL_PROTOCOL_OFFSET], 0x0017);
                if (!wtap_dump_file_write(wdh, irda_hdr, sizeof(irda_hdr), err))
                        return FALSE;
                wdh->bytes_dumped += sizeof(irda_hdr);
                break;

        case WTAP_ENCAP_MTP2_WITH_PHDR:
                /*
                 * Write the MTP2 header.
                 */
                memset(&mtp2_hdr, 0, sizeof(mtp2_hdr));
                mtp2_hdr[MTP2_SENT_OFFSET] = pseudo_header->mtp2.sent;
                mtp2_hdr[MTP2_ANNEX_A_USED_OFFSET] = pseudo_header->mtp2.annex_a_used;
                phtons(&mtp2_hdr[MTP2_LINK_NUMBER_OFFSET],
                    pseudo_header->mtp2.link_number);
                if (!wtap_dump_file_write(wdh, mtp2_hdr, sizeof(mtp2_hdr), err))
                        return FALSE;
                wdh->bytes_dumped += sizeof(mtp2_hdr);
                break;

        case WTAP_ENCAP_LINUX_LAPD:
                /*
                 * Write the LAPD header.
                 */
                memset(&lapd_hdr, 0, sizeof(lapd_hdr));
                phtons(&lapd_hdr[LAPD_SLL_PKTTYPE_OFFSET],
                    pseudo_header->lapd.pkttype);
                phtons(&lapd_hdr[LAPD_SLL_PROTOCOL_OFFSET], ETH_P_LAPD);
                lapd_hdr[LAPD_SLL_ADDR_OFFSET + 0] =
                    pseudo_header->lapd.we_network?0x01:0x00;
                if (!wtap_dump_file_write(wdh, lapd_hdr, sizeof(lapd_hdr), err))
                        return FALSE;
                wdh->bytes_dumped += sizeof(lapd_hdr);
                break;

        case WTAP_ENCAP_SITA:
                /*
                 * Write the SITA header.
                 */
                memset(&sita_hdr, 0, sizeof(sita_hdr));
                sita_hdr[SITA_FLAGS_OFFSET]   = pseudo_header->sita.sita_flags;
                sita_hdr[SITA_SIGNALS_OFFSET] = pseudo_header->sita.sita_signals;
                sita_hdr[SITA_ERRORS1_OFFSET] = pseudo_header->sita.sita_errors1;
                sita_hdr[SITA_ERRORS2_OFFSET] = pseudo_header->sita.sita_errors2;
                sita_hdr[SITA_PROTO_OFFSET]   = pseudo_header->sita.sita_proto;
                if (!wtap_dump_file_write(wdh, sita_hdr, sizeof(sita_hdr), err))
                        return FALSE;
                wdh->bytes_dumped += sizeof(sita_hdr);
                break;

        case WTAP_ENCAP_ERF:
                /*
                 * Write the ERF header.
                 */
                memset(&erf_hdr, 0, sizeof(erf_hdr));
                phtolell(&erf_hdr[0], pseudo_header->erf.phdr.ts);
                erf_hdr[8] = pseudo_header->erf.phdr.type;
                erf_hdr[9] = pseudo_header->erf.phdr.flags;
                phtons(&erf_hdr[10], pseudo_header->erf.phdr.rlen);
                phtons(&erf_hdr[12], pseudo_header->erf.phdr.lctr);
                phtons(&erf_hdr[14], pseudo_header->erf.phdr.wlen);
                size = sizeof(struct erf_phdr);

                switch(pseudo_header->erf.phdr.type & 0x7F) {
                case ERF_TYPE_MC_HDLC:
                case ERF_TYPE_MC_RAW:
                case ERF_TYPE_MC_ATM:
                case ERF_TYPE_MC_RAW_CHANNEL:
                case ERF_TYPE_MC_AAL5:
                case ERF_TYPE_MC_AAL2:
                case ERF_TYPE_COLOR_MC_HDLC_POS:
                        phtonl(&erf_hdr[16], pseudo_header->erf.subhdr.mc_hdr);
                        size += (int)sizeof(struct erf_mc_hdr);
                        break;
                case ERF_TYPE_ETH:
                case ERF_TYPE_COLOR_ETH:
                case ERF_TYPE_DSM_COLOR_ETH:
                        phtons(&erf_hdr[16], pseudo_header->erf.subhdr.eth_hdr);
                        size += (int)sizeof(struct erf_eth_hdr);
                        break;
                default:
                        break;
                }
                if (!wtap_dump_file_write(wdh, erf_hdr, size, err))
                        return FALSE;
                wdh->bytes_dumped += size;

                /*
                 * Now write out the extension headers.
                 */
                if (pseudo_header->erf.phdr.type & 0x80) {
                        int i = 0, max = sizeof(pseudo_header->erf.ehdr_list)/sizeof(struct erf_ehdr);
                        guint8 erf_exhdr[8];
                        guint8 type;

                        do {
                                phtonll(erf_exhdr, pseudo_header->erf.ehdr_list[i].ehdr);
                                type = erf_exhdr[0];
                                if (!wtap_dump_file_write(wdh, erf_exhdr, 8, err))
                                        return FALSE;
                                wdh->bytes_dumped += 8;
                                i++;
                        } while (type & 0x80 && i < max);
                }
                break;

        case WTAP_ENCAP_I2C:
                /*
                 * Write the I2C header.
                 */
                memset(&i2c_hdr, 0, sizeof(i2c_hdr));
                i2c_hdr.bus = pseudo_header->i2c.bus |
                        (pseudo_header->i2c.is_event ? 0x80 : 0x00);
                phtonl((guint8 *)&i2c_hdr.flags, pseudo_header->i2c.flags);
                if (!wtap_dump_file_write(wdh, &i2c_hdr, sizeof(i2c_hdr), err))
                        return FALSE;
                wdh->bytes_dumped += sizeof(i2c_hdr);
                break;

        case WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR:
                bt_hdr.direction = GUINT32_TO_BE(pseudo_header->p2p.sent ? LIBPCAP_BT_PHDR_SENT : LIBPCAP_BT_PHDR_RECV);
                if (!wtap_dump_file_write(wdh, &bt_hdr, sizeof bt_hdr, err))
                        return FALSE;
                wdh->bytes_dumped += sizeof bt_hdr;
                break;

        case WTAP_ENCAP_PPP_WITH_PHDR:
                ppp_hdr.direction = (pseudo_header->p2p.sent ? LIBPCAP_PPP_PHDR_SENT : LIBPCAP_PPP_PHDR_RECV);
                if (!wtap_dump_file_write(wdh, &ppp_hdr, sizeof ppp_hdr, err))
                        return FALSE;
                wdh->bytes_dumped += sizeof ppp_hdr;
                break;
        }
        return TRUE;
}