public dissect_krb5_PAC_NDRHEADERBLOB

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

/* pcap-common.c
 * Code common to pcap and pcapng file formats
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
 *
 * File format support for pcapng file format
 * Copyright (c) 2007 by Ulf Lamping <ulf.lamping@web.de>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"
#include "pcap-common.h"

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

/*
 * On some systems, the FDDI MAC addresses are bit-swapped.
 *
 * XXX - what we *really* need to know is whether the addresses are
 * bit-swapped *in a particular capture*, which depends on the system
 * on which it was captured, not on the system that's reading it.
 * Unfortunately, we can't determine that.
 */
#if !defined(ultrix) && !defined(__alpha) && !defined(__bsdi__)
#define BIT_SWAPPED_MAC_ADDRS
#endif

/*
 * 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
 * https://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 },
        { 2,            WTAP_ENCAP_3MB_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_LOOP },      /* 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 v1 */

        { 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 },

        /* ITU-T G.7041/Y.1303 Generic Framing Procedure. */
        { 170,          WTAP_ENCAP_GFP_T },
        { 171,          WTAP_ENCAP_GFP_F },

        /* 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 },
        /* Virtual Network Frames prepended with meta-information */
        { 184,          WTAP_ENCAP_JUNIPER_VN },
        /* USB packets from FreeBSD's USB BPF tap */
        { 186,          WTAP_ENCAP_USB_FREEBSD },
        /* 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/I2C with Kontron pseudo-header */
        { 199,          WTAP_ENCAP_IPMB_KONTRON },
        /* Juniper-private data link type, used for capturing data on a secure tunnel interface. */
        { 200,          WTAP_ENCAP_JUNIPER_ST },
        /* 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 },
        /* I2C with a Linux-specific header (defined by Pigeon Point Systems) */
        { 209,          WTAP_ENCAP_I2C_LINUX },
        /* 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 },
        /* STANAG 5066 - DTS(Data Transfer Sublayer) PDU */
        { 237,          WTAP_ENCAP_STANAG_5066_D_PDU },
        /* 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_PCAP },
        /* 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},
        /* Netlink Protocol (nlmon devices) */
        { 253,          WTAP_ENCAP_NETLINK },
        /* Bluetooth Linux Monitor */
        { 254,          WTAP_ENCAP_BLUETOOTH_LINUX_MONITOR },
        /* Bluetooth BR/EDR Baseband RF captures */
        { 255,          WTAP_ENCAP_BLUETOOTH_BREDR_BB },
        /* Bluetooth Low Energy Link Layer RF captures */
        { 256,          WTAP_ENCAP_BLUETOOTH_LE_LL_WITH_PHDR },

        /* Apple PKTAP */
        { 258,          WTAP_ENCAP_PKTAP },

        /* Ethernet Passive Optical Network */
        { 259,          WTAP_ENCAP_EPON },

        /* IPMI Trace Data Collection */
        { 260,          WTAP_ENCAP_IPMI_TRACE },

        /* ISO 14443 contactless smartcard standards */
        { 264,          WTAP_ENCAP_ISO14443 },

        /* USB packets from Darwin (macOS, iOS) BPF tap */
        { 266,          WTAP_ENCAP_USB_DARWIN },

        /* IBM SDLC frames containing SNA PDUs */
        { 268,          WTAP_ENCAP_SDLC },

        /* LoRaTap */
        { 270,          WTAP_ENCAP_LORATAP },

        /* Linux vsock */
        { 271,          WTAP_ENCAP_VSOCK },

        /* nRF Sniffer for Bluetooth LE */
        { 272,          WTAP_ENCAP_NORDIC_BLE },

        /* DOCSIS31 XRA31 Sniffer */
        { 273,          WTAP_ENCAP_DOCSIS31_XRA31 },

        /* mPackets as specified by 802.3br */
        { 274,          WTAP_ENCAP_ETHERNET_MPACKET },

        /* DisplayPort AUX channel monitor */
        { 275,          WTAP_ENCAP_DPAUXMON },

        /* Linux cooked capture v2 */
        { 276,          WTAP_ENCAP_SLL2 },

        /* Elektrobit High Speed Capture and Replay */
        { 279,          WTAP_ENCAP_EBHSCR },

        /* VPP dispatch trace */
        { 280,          WTAP_ENCAP_VPP },

        /* IEEE 802.15.4 TAP */
        { 283,          WTAP_ENCAP_IEEE802_15_4_TAP },

        /* Z-Wave Serial API */
        { 287,          WTAP_ENCAP_ZWAVE_SERIAL },

        /* USB 2.0/1.1/1.0 packets as transmitted over the cable */
        { 288,          WTAP_ENCAP_USB_2_0 },

        /* ATSC Link-Layer Protocol (A/330) packets */
        { 289,          WTAP_ENCAP_ATSC_ALP },

        /* Event Tracing for Windows records */
        { 290,          WTAP_ENCAP_ETW },

        /* Serial NCP (Network Co-Processor) protocol for Zigbee stack ZBOSS */
        { 292,          WTAP_ENCAP_ZBNCP },

        /* USB 2.0/1.1/1.0 packets captured on Low/Full/High speed link */
        { 293,          WTAP_ENCAP_USB_2_0_LOW_SPEED },
        { 294,          WTAP_ENCAP_USB_2_0_FULL_SPEED },
        { 295,          WTAP_ENCAP_USB_2_0_HIGH_SPEED },

        /* Auerswald log file captured from any supported Auerswald device */
        { 296,          WTAP_ENCAP_AUERSWALD_LOG },

        /* Silicon Labs debug channel */
        { 298,          WTAP_ENCAP_SILABS_DEBUG_CHANNEL },

        /* Ultra-wideband (UWB) controller interface protocol (UCI) */
        { 299,          WTAP_ENCAP_FIRA_UCI },

        /* MDB (Multi-Drop Bus) */
        { 300,          WTAP_ENCAP_MDB },

        /* DECT_NR (DECT-2020 New Radio (NR) MAC layer) */
        { 301,          WTAP_ENCAP_DECT_NR },

        /*
         * To repeat:
         *
         * If you need a new encapsulation type for pcap and pcapng 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 pcapng 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 version of
         * libpcap I've seen that define anything other than DLT_ATM_RFC1483
         * as 11 is the BSD/OS one, which defines DLT_FR as 11.  We handle
         * it as Frame Relay on BSD/OS and LLC-encapsulated ATM on all other
         * platforms.
         */
#if defined(__bsdi__) /* BSD/OS */
        { 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, on OpenBSD, interpret 12 as WTAP_ENCAP_LOOP,
         * otherwise, if we're not on BSD/OS, interpret it as
         * WTAP_ENCAP_RAW_IP.
         */
#if defined(__OpenBSD__)
        { 12,           WTAP_ENCAP_LOOP },
#elif defined(__bsdi__) /* BSD/OS */
        /*
         * 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
         * treat 13 as WTAP_ENCAP_ATM_RFC1483, but, on all other
         * systems, we can read OpenBSD DLT_ENC captures.
         */
#if defined(__bsdi__) /* BSD/OS */
        { 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(__NetBSD__)
        { 16,           WTAP_ENCAP_CHDLC },
#elif !defined(__bsdi__)
        /*
         * If you care about the two different Linux interpretations
         * of 16, fix it yourself.
         */
        { 16,           WTAP_ENCAP_LINUX_ATM_CLIP },
#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 on OpenBSD and don't
         * use it otherwise.
         */
#if defined(__OpenBSD__)
        { 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 version of 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 version of libpcap file 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 pcap and pcapng 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 array_length(pcap_to_wtap_map)

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;
}

/*
 * For most encapsulations, we use WTAP_MAX_PACKET_SIZE_STANDARD, as
 * that should be enough for most link-layer types, and shouldn't be
 * too big.
 *
 * For some link-layer types, we use larger types, because, for each
 * of them, the maximum packet size is larger than the standard
 * maximum, and is bigger than we'd want for all link-layer types - files
 * with that snapshot length might cause some programs reading them to
 * allocate a huge and wasteful buffer and, at least on 32-bit platforms,
 * run the risk of running out of memory.
 */
unsigned
wtap_max_snaplen_for_encap(int wtap_encap)
{
        switch (wtap_encap) {

        case WTAP_ENCAP_DBUS:
                return WTAP_MAX_PACKET_SIZE_DBUS;

        case WTAP_ENCAP_EBHSCR:
                return WTAP_MAX_PACKET_SIZE_EBHSCR;

        case WTAP_ENCAP_USBPCAP:
        case WTAP_ENCAP_USB_LINUX:
        case WTAP_ENCAP_USB_LINUX_MMAPPED:
        case WTAP_ENCAP_USB_DARWIN:
        case WTAP_ENCAP_USB_FREEBSD:
                return WTAP_MAX_PACKET_SIZE_USBPCAP;

        default:
                return WTAP_MAX_PACKET_SIZE_STANDARD;
        }
}

/*
 * 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 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 */

static int
pcap_read_nokiaatm_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, unsigned packet_size,
    int *err, char **err_info)
{
        uint8_t atm_phdr[NOKIAATM_LEN];
        uint8_t vpi;
        uint16_t        vci;

        if (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 = ws_strdup_printf("pcap/pcapng: Nokia IPSO ATM file has a %u-byte packet, too small to have even an ATM pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, atm_phdr, NOKIAATM_LEN, err, err_info))
                return -1;

        vpi = atm_phdr[NOKIAATM_VPI];
        vci = pntoh16(&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 NOKIAATM_LEN;
}

/*
 * 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 */

static int
pcap_read_sunatm_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, unsigned packet_size,
    int *err, char **err_info)
{
        uint8_t atm_phdr[SUNATM_LEN];
        uint8_t vpi;
        uint16_t        vci;

        if (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 = ws_strdup_printf("pcap/pcapng: SunATM file has a %u-byte packet, too small to have even an ATM pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, atm_phdr, SUNATM_LEN, err, err_info))
                return -1;

        vpi = atm_phdr[SUNATM_VPI];
        vci = pntoh16(&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 SUNATM_LEN;
}

static bool
pcap_write_sunatm_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t atm_hdr[SUNATM_LEN];

        /*
         * 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] = (uint8_t)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;
        return true;
}

/*
 * 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 */

static int
pcap_read_irda_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        uint8_t irda_phdr[IRDA_SLL_LEN];

        if (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 = ws_strdup_printf("pcap/pcapng: IrDA file has a %u-byte packet, too small to have even an IrDA pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, irda_phdr, IRDA_SLL_LEN, err, err_info))
                return -1;

        if (pntoh16(&irda_phdr[IRDA_SLL_PROTOCOL_OFFSET]) != 0x0017) {
                *err = WTAP_ERR_BAD_FILE;
                if (err_info != NULL)
                        *err_info = g_strdup("pcap/pcapng: IrDA capture has a packet with an invalid sll_protocol field");
                return -1;
        }

        pseudo_header->irda.pkttype = pntoh16(&irda_phdr[IRDA_SLL_PKTTYPE_OFFSET]);

        return IRDA_SLL_LEN;
}

static bool
pcap_write_irda_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t irda_hdr[IRDA_SLL_LEN];

        /*
         * 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;
        return true;
}

/*
 * 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 */

static int
pcap_read_mtp2_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        uint8_t mtp2_hdr[MTP2_HDR_LEN];

        if (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 = ws_strdup_printf("pcap/pcapng: MTP2 file has a %u-byte packet, too small to have even an MTP2 pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, mtp2_hdr, MTP2_HDR_LEN, err, err_info))
                return -1;

        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  = pntoh16(&mtp2_hdr[MTP2_LINK_NUMBER_OFFSET]);

        return MTP2_HDR_LEN;
}

static bool
pcap_write_mtp2_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t mtp2_hdr[MTP2_HDR_LEN];

        /*
         * 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;
        return true;
}

/*
 * 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 */

static int
pcap_read_lapd_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        uint8_t lapd_phdr[LAPD_SLL_LEN];

        if (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 = ws_strdup_printf("pcap/pcapng: LAPD file has a %u-byte packet, too small to have even a LAPD pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, lapd_phdr, LAPD_SLL_LEN, err, err_info))
                return -1;

        if (pntoh16(&lapd_phdr[LAPD_SLL_PROTOCOL_OFFSET]) != ETH_P_LAPD) {
                *err = WTAP_ERR_BAD_FILE;
                if (err_info != NULL)
                        *err_info = g_strdup("pcap/pcapng: LAPD capture has a packet with an invalid sll_protocol field");
                return -1;
        }

        pseudo_header->lapd.pkttype = pntoh16(&lapd_phdr[LAPD_SLL_PKTTYPE_OFFSET]);
        pseudo_header->lapd.we_network = !!lapd_phdr[LAPD_SLL_ADDR_OFFSET+0];

        return LAPD_SLL_LEN;
}

static bool
pcap_write_lapd_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t lapd_hdr[LAPD_SLL_LEN];

        /*
         * 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;
        return true;
}

/*
 * 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 */

static int
pcap_read_sita_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        uint8_t sita_phdr[SITA_HDR_LEN];

        if (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 = ws_strdup_printf("pcap/pcapng: SITA file has a %u-byte packet, too small to have even a SITA pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, sita_phdr, SITA_HDR_LEN, err, err_info))
                return -1;

        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 SITA_HDR_LEN;
}

static bool
pcap_write_sita_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t sita_hdr[SITA_HDR_LEN];

        /*
         * 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;
        return true;
}

/*
 * Pseudo-header at the beginning of DLT_BLUETOOTH_HCI_H4_WITH_PHDR frames.
 * Values in network byte order.
 */
struct pcap_bt_phdr {
        uint32_t direction;     /* Bit 0 hold the frame direction. */
};

#define LIBPCAP_BT_PHDR_SENT    0
#define LIBPCAP_BT_PHDR_RECV    1

static int
pcap_read_bt_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        struct pcap_bt_phdr phdr;

        if (packet_size < sizeof (struct pcap_bt_phdr)) {
                /*
                 * Uh-oh, the packet isn't big enough to even
                 * have a pseudo-header.
                 */
                *err = WTAP_ERR_BAD_FILE;
                *err_info = ws_strdup_printf("pcap/pcapng: Bluetooth file has a %u-byte packet, too small to have even a pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, &phdr, sizeof (struct pcap_bt_phdr),
            err, err_info))
                return -1;
        pseudo_header->p2p.sent = ((g_ntohl(phdr.direction) & LIBPCAP_BT_PHDR_RECV) == 0)? true: false;
        return (int)sizeof (struct pcap_bt_phdr);
}

static bool
pcap_write_bt_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint32_t direction;
        struct pcap_bt_phdr bt_hdr;

        direction = pseudo_header->p2p.sent ? LIBPCAP_BT_PHDR_SENT : LIBPCAP_BT_PHDR_RECV;
        bt_hdr.direction = GUINT32_TO_BE(direction);
        if (!wtap_dump_file_write(wdh, &bt_hdr, sizeof bt_hdr, err))
                return false;
        return true;
}

/*
 * Pseudo-header at the beginning of DLT_BLUETOOTH_LINUX_MONITOR frames.
 * Values in network byte order.
 */
struct pcap_bt_monitor_phdr {
        uint16_t adapter_id;
        uint16_t opcode;
};

static int
pcap_read_bt_monitor_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, unsigned packet_size,
    int *err, char **err_info)
{
        struct pcap_bt_monitor_phdr phdr;

        if (packet_size < sizeof (struct pcap_bt_monitor_phdr)) {
                /*
                 * Uh-oh, the packet isn't big enough to even
                 * have a pseudo-header.
                 */
                *err = WTAP_ERR_BAD_FILE;
                *err_info = ws_strdup_printf("pcap/pcapng: Bluetooth monitor file has a %u-byte packet, too small to have even a pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, &phdr, sizeof (struct pcap_bt_monitor_phdr),
            err, err_info))
                return -1;

        pseudo_header->btmon.adapter_id = g_ntohs(phdr.adapter_id);
        pseudo_header->btmon.opcode = g_ntohs(phdr.opcode);
        return (int)sizeof (struct pcap_bt_monitor_phdr);
}

static bool
pcap_write_bt_monitor_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        struct pcap_bt_monitor_phdr bt_monitor_hdr;

        bt_monitor_hdr.adapter_id = GUINT16_TO_BE(pseudo_header->btmon.adapter_id);
        bt_monitor_hdr.opcode = GUINT16_TO_BE(pseudo_header->btmon.opcode);

        if (!wtap_dump_file_write(wdh, &bt_monitor_hdr, sizeof bt_monitor_hdr, err))
                return false;
        return true;
}

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

static int
pcap_read_llcp_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, unsigned packet_size,
    int *err, char **err_info)
{
        uint8_t phdr[LLCP_HEADER_LEN];

        if (packet_size < LLCP_HEADER_LEN) {
                *err = WTAP_ERR_BAD_FILE;
                *err_info = ws_strdup_printf("pcap/pcapng: NFC LLCP file has a %u-byte packet, too small to have even a pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, phdr, LLCP_HEADER_LEN, err, err_info))
                return -1;
        pseudo_header->llcp.adapter = phdr[LLCP_ADAPTER_OFFSET];
        pseudo_header->llcp.flags = phdr[LLCP_FLAGS_OFFSET];
        return LLCP_HEADER_LEN;
}

static bool
pcap_write_llcp_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t phdr[LLCP_HEADER_LEN];

        phdr[LLCP_ADAPTER_OFFSET] = pseudo_header->llcp.adapter;
        phdr[LLCP_FLAGS_OFFSET] = pseudo_header->llcp.flags;
        if (!wtap_dump_file_write(wdh, &phdr, sizeof phdr, err))
                return false;
        return true;
}

/*
 * Pseudo-header at the beginning of DLT_PPP_WITH_DIR frames.
 */
struct pcap_ppp_phdr {
        uint8_t direction;
};

/*
 * Pseudo-header at the beginning of DLT_PPP_WITH_DIR frames.
 */
static int
pcap_read_ppp_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        struct pcap_ppp_phdr phdr;

        if (packet_size < sizeof (struct pcap_ppp_phdr)) {
                /*
                 * Uh-oh, the packet isn't big enough to even
                 * have a pseudo-header.
                 */
                *err = WTAP_ERR_BAD_FILE;
                *err_info = ws_strdup_printf("pcap/pcapng: PPP file has a %u-byte packet, too small to have even a pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, &phdr, sizeof (struct pcap_ppp_phdr),
            err, err_info))
                return -1;
        /* Any non-zero value means "sent" */
        pseudo_header->p2p.sent = (phdr.direction != 0) ? true: false;
        return (int)sizeof (struct pcap_ppp_phdr);
}

static bool
pcap_write_ppp_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        struct pcap_ppp_phdr ppp_hdr;

        /* Any non-zero value means "sent" */
        ppp_hdr.direction = (pseudo_header->p2p.sent ? 1 : 0);
        if (!wtap_dump_file_write(wdh, &ppp_hdr, sizeof ppp_hdr, err))
                return false;
        return true;
}

static int
pcap_read_erf_pseudoheader(FILE_T fh, wtap_rec *rec,
    union wtap_pseudo_header *pseudo_header, unsigned packet_size,
    int *err, char **err_info)
{
        uint8_t erf_hdr[sizeof(struct erf_phdr)];
        uint8_t erf_subhdr[sizeof(union erf_subhdr)];
        int phdr_len;

        if (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 = ws_strdup_printf("pcap/pcapng: ERF file has a %u-byte packet, too small to have even an ERF pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, erf_hdr, sizeof(struct erf_phdr), err, err_info))
                return -1;
        phdr_len = (int)sizeof(struct erf_phdr);
        pseudo_header->erf.phdr.ts = pletoh64(&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 = pntoh16(&erf_hdr[10]);
        pseudo_header->erf.phdr.lctr = pntoh16(&erf_hdr[12]);
        pseudo_header->erf.phdr.wlen = pntoh16(&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 (rec) {
                uint64_t ts = pseudo_header->erf.phdr.ts;
                rec->ts.secs = (time_t) (ts >> 32);
                ts = ((ts & 0xffffffff) * 1000 * 1000 * 1000);
                ts += (ts & 0x80000000) << 1; /* rounding */
                rec->ts.nsecs = ((uint32_t) (ts >> 32));
                if (rec->ts.nsecs >= 1000000000) {
                        rec->ts.nsecs -= 1000000000;
                        rec->ts.secs += 1;
                }

                /*
                 * This time stamp came from the ERF header, not from the
                 * pcap packet header or pcapng block header, so its
                 * precision is that of ERF time stamps, not the pcap
                 * file's time stamp or the pcapng interface's time
                 * stamp.
                 */
                rec->tsprec = WTAP_TSPREC_NSEC;
        }

        /*
         * If the type of record given in the pseudo header indicates
         * the presence of an extension header, then read all the
         * extension headers.
         */
        if (pseudo_header->erf.phdr.type & 0x80) {
                int i = 0, max = array_length(pseudo_header->erf.ehdr_list);
                uint8_t erf_exhdr[8];
                uint8_t type;

                do {
                        if (phdr_len > INT_MAX - 8) {
                                *err = WTAP_ERR_BAD_FILE;
                                *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a packet larger than %d bytes",
                                    INT_MAX);
                                return -1;
                        }
                        if (packet_size < (unsigned)phdr_len + 8) {
                                *err = WTAP_ERR_BAD_FILE;
                                *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a %u-byte packet, too small to include the extension headers",
                                    packet_size);
                                return -1;
                        }
                        if (!wtap_read_bytes(fh, erf_exhdr, 8, err, err_info))
                                return -1;
                        type = erf_exhdr[0];
                        if (i < max) {
                                uint64_t erf_exhdr_sw;

                                erf_exhdr_sw = pntoh64(erf_exhdr);
                                memcpy(&pseudo_header->erf.ehdr_list[i].ehdr, &erf_exhdr_sw, sizeof(erf_exhdr_sw));
                        }
                        phdr_len += 8;
                        i++;
                } while (type & 0x80);
        }

        /* check the optional subheader */
        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 */
                if (phdr_len > INT_MAX - (int)sizeof(erf_mc_header_t)) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a packet larger than %d bytes",
                            INT_MAX);
                        return -1;
                }
                if (packet_size < (unsigned)(phdr_len + (int)sizeof(erf_mc_header_t))) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a %u-byte packet, too small to include the Multi Channel header",
                            packet_size);
                        return -1;
                }
                if (!wtap_read_bytes(fh, erf_subhdr, sizeof(erf_mc_header_t), err, err_info))
                        return -1;
                pseudo_header->erf.subhdr.mc_hdr = pntoh32(&erf_subhdr[0]);
                phdr_len += sizeof(erf_mc_header_t);
                break;
        case ERF_TYPE_AAL2:
                /* Extract the AAL2 header to include it in the pseudo header part */
                if (phdr_len > INT_MAX - (int)sizeof(erf_aal2_header_t)) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a packet larger than %d bytes",
                            INT_MAX);
                        return -1;
                }
                if (packet_size < (unsigned)(phdr_len + (int)sizeof(erf_aal2_header_t))) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a %u-byte packet, too small to include the AAL2 header",
                            packet_size);
                        return -1;
                }
                if (!wtap_read_bytes(fh, erf_subhdr, sizeof(erf_aal2_header_t), err, err_info))
                        return -1;
                pseudo_header->erf.subhdr.aal2_hdr = pntoh32(&erf_subhdr[0]);
                phdr_len += sizeof(erf_aal2_header_t);
                break;
        case ERF_TYPE_ETH:
        case ERF_TYPE_COLOR_ETH:
        case ERF_TYPE_DSM_COLOR_ETH:
        case ERF_TYPE_COLOR_HASH_ETH:
                /* Extract the Ethernet additional header to include it in the pseudo header part */
                if (phdr_len > INT_MAX - (int)sizeof(erf_eth_header_t)) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a packet larger than %d bytes",
                            INT_MAX);
                        return -1;
                }
                if (packet_size < (unsigned)(phdr_len + (int)sizeof(erf_eth_header_t))) {
                        *err = WTAP_ERR_BAD_FILE;
                        *err_info = ws_strdup_printf("pcap/pcapng: ERF file has a %u-byte packet, too small to include the Ethernet additional header",
                            packet_size);
                        return -1;
                }
                if (!wtap_read_bytes(fh, erf_subhdr, sizeof(erf_eth_header_t), err, err_info))
                        return -1;
                memcpy(&pseudo_header->erf.subhdr.eth_hdr, erf_subhdr, sizeof pseudo_header->erf.subhdr.eth_hdr);
                phdr_len += sizeof(erf_eth_header_t);
                break;
        default:
                /* No optional pseudo header for this ERF type */
                break;
        }
        return phdr_len;
}

static bool
pcap_write_erf_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        uint8_t erf_hdr[sizeof(struct erf_phdr)];
        uint8_t erf_subhdr[sizeof(union erf_subhdr)];

        /*
         * 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;

        /*
         * Recalculate rlen as padding (and maybe extension headers)
         * have been stripped from caplen.
         *
         * XXX: Since we don't have rec->rec_header.packet_header.caplen
         * here, assume caplen was calculated correctly and
         * recalculate from wlen.
         */
        phtons(&erf_hdr[10],
            MIN(pseudo_header->erf.phdr.rlen, pseudo_header->erf.phdr.wlen + pcap_get_phdr_size(WTAP_ENCAP_ERF, pseudo_header)));

        phtons(&erf_hdr[12], pseudo_header->erf.phdr.lctr);
        phtons(&erf_hdr[14], pseudo_header->erf.phdr.wlen);
        if (!wtap_dump_file_write(wdh, erf_hdr,  sizeof(struct erf_phdr), err))
                return false;

        /*
         * Now write out the extension headers.
         */
        if (pseudo_header->erf.phdr.type & 0x80) {
                int i = 0, max = array_length(pseudo_header->erf.ehdr_list);
                uint8_t erf_exhdr[8];
                uint8_t type;

                do {
                        phtonll(erf_exhdr, pseudo_header->erf.ehdr_list[i].ehdr);
                        type = erf_exhdr[0];
                        /* Clear more extension headers bit if > 8 */
                        if(i == max-1)
                                erf_exhdr[0] = erf_exhdr[0] & 0x7F;
                        if (!wtap_dump_file_write(wdh, erf_exhdr, 8, err))
                                return false;
                        i++;
                } while (type & 0x80 && i < max);
        }

        /*
         * Now write out the subheader, if any
         */
        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_subhdr[0], pseudo_header->erf.subhdr.mc_hdr);
                if (!wtap_dump_file_write(wdh, erf_subhdr,
                    sizeof(struct erf_mc_hdr), err))
                        return false;
                break;
        case ERF_TYPE_AAL2:
                phtonl(&erf_subhdr[0], pseudo_header->erf.subhdr.aal2_hdr);
                if (!wtap_dump_file_write(wdh, erf_subhdr,
                    sizeof(struct erf_aal2_hdr), err))
                        return false;
                break;
        case ERF_TYPE_ETH:
        case ERF_TYPE_COLOR_ETH:
        case ERF_TYPE_DSM_COLOR_ETH:
        case ERF_TYPE_COLOR_HASH_ETH:
                memcpy(&erf_subhdr[0], &pseudo_header->erf.subhdr.eth_hdr, sizeof pseudo_header->erf.subhdr.eth_hdr);
                if (!wtap_dump_file_write(wdh, erf_subhdr,
                    sizeof(struct erf_eth_hdr), err))
                        return false;
                break;
        default:
                break;
        }
        return true;
}

/*
 * I2C-with=Linux-pseudoheader link-layer on-disk format, as defined by
 * Pigeon Point Systems.
 */
struct i2c_linux_file_hdr {
        uint8_t bus;
        uint8_t flags[4];
};

static int
pcap_read_i2c_linux_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    unsigned packet_size, int *err, char **err_info)
{
        struct i2c_linux_file_hdr i2c_linux_hdr;

        if (packet_size < sizeof (struct i2c_linux_file_hdr)) {
                /*
                 * Uh-oh, the packet isn't big enough to even
                 * have a pseudo-header.
                 */
                *err = WTAP_ERR_BAD_FILE;
                *err_info = ws_strdup_printf("pcap/pcapng: I2C file has a %u-byte packet, too small to have even a I2C pseudo-header",
                    packet_size);
                return -1;
        }
        if (!wtap_read_bytes(fh, &i2c_linux_hdr, sizeof (i2c_linux_hdr), err, err_info))
                return -1;

        pseudo_header->i2c.is_event = i2c_linux_hdr.bus & 0x80 ? 1 : 0;
        pseudo_header->i2c.bus = i2c_linux_hdr.bus & 0x7f;
        pseudo_header->i2c.flags = pntoh32(&i2c_linux_hdr.flags);

        return (int)sizeof (struct i2c_linux_file_hdr);
}

static bool
pcap_write_i2c_linux_pseudoheader(wtap_dumper *wdh,
    const union wtap_pseudo_header *pseudo_header, int *err)
{
        struct i2c_linux_file_hdr i2c_linux_hdr;

        /*
         * Write the I2C Linux-specific pseudo-header.
         */
        memset(&i2c_linux_hdr, 0, sizeof(i2c_linux_hdr));
        i2c_linux_hdr.bus = pseudo_header->i2c.bus |
                        (pseudo_header->i2c.is_event ? 0x80 : 0x00);
        phtonl((uint8_t *)&i2c_linux_hdr.flags, pseudo_header->i2c.flags);
        if (!wtap_dump_file_write(wdh, &i2c_linux_hdr, sizeof(i2c_linux_hdr), err))
                return false;
        return true;
}

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

static bool
pcap_read_nokia_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, char **err_info)
{
        uint8_t phdr[NOKIA_LEN];


        /* 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;
        }

        if (!wtap_read_bytes(fh, phdr, NOKIA_LEN, err, err_info))
                return false;

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

        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 {
        int32_t error_count;
        int32_t 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 {
        uint64_t id;             /* urb id, to link submission and completion events */
        uint8_t event_type;      /* Submit ('S'), Completed ('C'), Error ('E') */
        uint8_t transfer_type;   /* ISO (0), Intr, Control, Bulk (3) */
        uint8_t endpoint_number; /* Endpoint number (0-15) and transfer direction */
        uint8_t device_address;  /* 0-127 */
        uint16_t bus_id;
        int8_t setup_flag;       /* 0, if the urb setup header is meaningful */
        int8_t data_flag;        /* 0, if urb data is present */
        int64_t ts_sec;
        int32_t ts_usec;
        int32_t status;
        uint32_t urb_len;        /* whole len of urb this event refers to */
        uint32_t 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 {
                uint8_t 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.
         */
        int32_t interval;    /* only for Interrupt and Isochronous events */
        int32_t start_frame; /* for Isochronous */
        uint32_t xfer_flags; /* copy of URB's transfer_flags */
        uint32_t ndesc;      /* actual number of isochronous descriptors */
};

/*
 * event_type values
 */
#define URB_SUBMIT        'S'
#define URB_COMPLETE      'C'
#define URB_ERROR         'E'

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

#define URB_TRANSFER_IN   0x80          /* to host */

struct linux_usb_isodesc {
        int32_t iso_status;
        uint32_t iso_off;
        uint32_t iso_len;
        uint32_t _pad;
};

/*
 * USB setup header as defined in USB specification
 * See usb_20.pdf, Chapter 9.3 'USB Device Requests' for details.
 * https://www.usb.org/document-library/usb-20-specification
 *
 * This structure is 8 bytes long.
 */
struct usb_device_setup_hdr {
        int8_t bmRequestType;
        uint8_t bRequest;
        uint16_t wValue;
        uint16_t wIndex;
        uint16_t 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))

/*
 * Is that offset within the bounds of the packet?
 */
#define WITHIN_PACKET(basep, fieldp) \
        (packet_size >= END_OFFSETOF((basep), (fieldp)))

#define CHECK_AND_SWAP16(fieldp) \
        { \
                if (!WITHIN_PACKET(usb_phdr, fieldp)) \
                        return; \
                PBSWAP16((uint8_t *)fieldp); \
        }

#define CHECK_AND_SWAP32(fieldp) \
        { \
                if (!WITHIN_PACKET(usb_phdr, fieldp)) \
                        return; \
                PBSWAP32((uint8_t *)fieldp); \
        }

#define CHECK_AND_SWAP64(fieldp) \
        { \
                if (!WITHIN_PACKET(usb_phdr, fieldp)) \
                        return; \
                PBSWAP64((uint8_t *)fieldp); \
        }

/*
 * Offset and length of the CAN ID field in the CAN classic/CAN FD
 * SocketCAN header.
 */
#define CAN_CANFD_CAN_ID_OFFSET         0
#define CAN_CANFD_CAN_ID_LEN            4

/*
 * Offsets and lengths of fields in the CAN XL SocketCAN header.
 */
#define CANXL_PRIORITY_VCID_OFFSET      0
#define CANXL_PRIORITY_VCID_LEN         4
#define CANXL_FLAGS_OFFSET              (CANXL_PRIORITY_VCID_OFFSET + CANXL_PRIORITY_VCID_LEN)
#define CANXL_FLAGS_LEN                 1
#define CANXL_SDU_TYPE_OFFSET           (CANXL_FLAGS_OFFSET + CANXL_FLAGS_LEN)
#define CANXL_SDU_TYPE_LEN              1
#define CANXL_PAYLOAD_LENGTH_OFFSET     (CANXL_SDU_TYPE_OFFSET + CANXL_SDU_TYPE_LEN)
#define CANXL_PAYLOAD_LENGTH_LEN        2
#define CANXL_ACCEPTANCE_FIELD_OFFSET   (CANXL_PAYLOAD_LENGTH_OFFSET + CANXL_PAYLOAD_LENGTH_LEN)
#define CANXL_ACCEPTANCE_FIELD_LEN      4

/*
 * CAN fake link-layer headers in Linux cooked packets.
 */
#define LINUX_SLL_PROTOCOL_OFFSET       14      /* protocol */
#define LINUX_SLL_LEN                   16      /* length of the header */

#define LINUX_SLL2_PROTOCOL_OFFSET      0       /* protocol */
#define LINUX_SLL2_LEN                  20      /* length of the header */

/*
 * The protocols we have to check for.
 */
#define LINUX_SLL_P_CAN                 0x000C  /* Controller Area Network classic */
#define LINUX_SLL_P_CANFD               0x000D  /* Controller Area Network flexible data rate */
#define LINUX_SLL_P_CANXL               0x000E  /* Controller Area Network extended length */

static void
pcap_byteswap_can_socketcan_pseudoheader(unsigned packet_size, uint16_t protocol,
    uint8_t *pd)
{
        switch (protocol) {

        case LINUX_SLL_P_CAN:
        case LINUX_SLL_P_CANFD:
                /*
                 * CAN classic or CAN FD; byte-swap the ID/flags field
                 * into our host byte order.
                 *
                 * Make sure we have the entire field.
                 */
                if (packet_size < (CAN_CANFD_CAN_ID_OFFSET + CAN_CANFD_CAN_ID_LEN)) {
                        /* Not enough data to have the full CAN ID */
                        return;
                }
                PBSWAP32(&pd[CAN_CANFD_CAN_ID_OFFSET]);
                break;

        case LINUX_SLL_P_CANXL:
                /*
                 * CAN classic or CAN FD; byte-swap the priority-and-VCID
                 * field, the payload length, ad the acceptance field
                 * into our host byte order.
                 */
                if (packet_size < (CANXL_PRIORITY_VCID_OFFSET + CANXL_PRIORITY_VCID_LEN)) {
                        /* Not enough data to have the full priority/VCID field */
                        return;
                }
                PBSWAP32(&pd[CANXL_PRIORITY_VCID_OFFSET]);
                if (packet_size < (CANXL_PAYLOAD_LENGTH_OFFSET + CANXL_PAYLOAD_LENGTH_LEN)) {
                        /* Not enough data to have the full payload length field */
                        return;
                }
                PBSWAP16(&pd[CANXL_PAYLOAD_LENGTH_OFFSET]);
                if (packet_size < (CANXL_ACCEPTANCE_FIELD_OFFSET + CANXL_ACCEPTANCE_FIELD_LEN)) {
                        /* Not enough data to have the full payload length field */
                        return;
                }
                PBSWAP32(&pd[CANXL_ACCEPTANCE_FIELD_OFFSET]);
                break;

        default:
                /* Not a CAN packet; nothing to fix */
                return;
        }
}

static void
pcap_byteswap_linux_sll_pseudoheader(wtap_rec *rec, uint8_t *pd)
{
        unsigned packet_size;
        uint16_t protocol;

        /*
         * Minimum of captured and actual length (just in case the
         * actual length < the captured length, which Should Never
         * Happen).
         */
        packet_size = rec->rec_header.packet_header.caplen;
        if (packet_size > rec->rec_header.packet_header.len)
                packet_size = rec->rec_header.packet_header.len;

        if (packet_size < LINUX_SLL_LEN) {
                /* Not enough data to have the protocol */
                return;
        }

        /*
         * Byte-swap the SocketCAN pseudoheader, if we have one.
         */
        protocol = pntoh16(&pd[LINUX_SLL_PROTOCOL_OFFSET]);
        pcap_byteswap_can_socketcan_pseudoheader(packet_size - LINUX_SLL_LEN,
            protocol, pd + LINUX_SLL_LEN);
}

static void
pcap_byteswap_linux_sll2_pseudoheader(wtap_rec *rec, uint8_t *pd)
{
        unsigned packet_size;
        uint16_t protocol;

        /*
         * Minimum of captured and actual length (just in case the
         * actual length < the captured length, which Should Never
         * Happen).
         */
        packet_size = rec->rec_header.packet_header.caplen;
        if (packet_size > rec->rec_header.packet_header.len)
                packet_size = rec->rec_header.packet_header.len;

        if (packet_size < LINUX_SLL2_LEN) {
                /* Not enough data to have the protocol */
                return;
        }

        /*
         * Byte-swap the SocketCAN pseudoheader, if we have one.
         */
        protocol = pntoh16(&pd[LINUX_SLL2_PROTOCOL_OFFSET]);
        pcap_byteswap_can_socketcan_pseudoheader(packet_size - LINUX_SLL2_LEN,
            protocol, pd + LINUX_SLL2_LEN);
}

static void
pcap_byteswap_linux_usb_pseudoheader(wtap_rec *rec, uint8_t *pd,
    bool header_len_64_bytes)
{
        unsigned packet_size;
        struct linux_usb_phdr *usb_phdr;
        struct linux_usb_isodesc *pisodesc;
        int32_t iso_numdesc, i;

        /*
         * Minimum of captured and actual length (just in case the
         * actual length < the captured length, which Should Never
         * Happen).
         */
        packet_size = rec->rec_header.packet_header.caplen;
        if (packet_size > rec->rec_header.packet_header.len)
                packet_size = rec->rec_header.packet_header.len;

        /*
         * Greasy hack, but we never directly dereference any of
         * the fields in *usb_phdr, we just get offsets of and
         * addresses of its members and byte-swap it with a
         * byte-at-a-time macro, so it's alignment-safe.
         */
        usb_phdr = (struct linux_usb_phdr *)(void *)pd;

        CHECK_AND_SWAP64(&usb_phdr->id);
        CHECK_AND_SWAP16(&usb_phdr->bus_id);
        CHECK_AND_SWAP64(&usb_phdr->ts_sec);
        CHECK_AND_SWAP32(&usb_phdr->ts_usec);
        CHECK_AND_SWAP32(&usb_phdr->status);
        CHECK_AND_SWAP32(&usb_phdr->urb_len);
        CHECK_AND_SWAP32(&usb_phdr->data_len);

        if (usb_phdr->transfer_type == URB_ISOCHRONOUS) {
                CHECK_AND_SWAP32(&usb_phdr->s.iso.error_count);
                CHECK_AND_SWAP32(&usb_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 usb_phdr, not usb_phdr_ext; we want the offset of
                 * the additional fields from the beginning of
                 * the packet.
                 */
                CHECK_AND_SWAP32(&usb_phdr->interval);
                CHECK_AND_SWAP32(&usb_phdr->start_frame);
                CHECK_AND_SWAP32(&usb_phdr->xfer_flags);
                CHECK_AND_SWAP32(&usb_phdr->ndesc);
        }

        if (usb_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 = usb_phdr->s.iso.numdesc;
                for (i = 0; i < iso_numdesc; i++) {
                        CHECK_AND_SWAP32(&pisodesc->iso_status);
                        CHECK_AND_SWAP32(&pisodesc->iso_off);
                        CHECK_AND_SWAP32(&pisodesc->iso_len);
                        CHECK_AND_SWAP32(&pisodesc->_pad);

                        pisodesc++;
                }
        }
}

struct nflog_hdr {
        uint8_t nflog_family;           /* address family */
        uint8_t nflog_version;          /* version */
        uint16_t nflog_rid;             /* resource ID */
};

struct nflog_tlv {
        uint16_t tlv_length;            /* tlv length */
        uint16_t tlv_type;              /* tlv type */
        /* value follows this */
};

static void
pcap_byteswap_nflog_pseudoheader(wtap_rec *rec, uint8_t *pd)
{
        unsigned packet_size;
        uint8_t *p;
        struct nflog_hdr *nfhdr;
        struct nflog_tlv *tlv;
        unsigned size;

        /*
         * Minimum of captured and actual length (just in case the
         * actual length < the captured length, which Should Never
         * Happen).
         */
        packet_size = rec->rec_header.packet_header.caplen;
        if (packet_size > rec->rec_header.packet_header.len)
                packet_size = rec->rec_header.packet_header.len;

        if (packet_size < sizeof(struct nflog_hdr)) {
                /* Not enough data to have any TLVs. */
                return;
        }

        p = pd;
        nfhdr = (struct nflog_hdr *)pd;
        if (nfhdr->nflog_version != 0) {
                /* Unknown NFLOG version */
                return;
        }

        packet_size -= (unsigned)sizeof(struct nflog_hdr);
        p += sizeof(struct nflog_hdr);

        while (packet_size >= sizeof(struct nflog_tlv)) {
                tlv = (struct nflog_tlv *) p;

                /* Swap the type and length. */
                PBSWAP16((uint8_t *)&tlv->tlv_type);
                PBSWAP16((uint8_t *)&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(struct nflog_tlv)) {
                        /* Yes. Give up now. */
                        return;
                }

                /* Do we have enough data for the full TLV? */
                if (packet_size < size) {
                        /* No. */
                        return;
                }

                /* Skip over the TLV. */
                packet_size -= size;
                p += size;
        }
}

/*
 * pflog headers, at least as they exist now.
 */
#define PFLOG_IFNAMSIZ          16
#define PFLOG_RULESET_NAME_SIZE 16

struct pfloghdr {
        uint8_t         length;
        uint8_t         af;
        uint8_t         action;
        uint8_t         reason;
        char            ifname[PFLOG_IFNAMSIZ];
        char            ruleset[PFLOG_RULESET_NAME_SIZE];
        uint32_t                rulenr;
        uint32_t                subrulenr;
        uint32_t                uid;
        int32_t         pid;
        uint32_t                rule_uid;
        int32_t         rule_pid;
        uint8_t         dir;
        /* More follows, depending on the header length */
};

static void
pcap_byteswap_pflog_pseudoheader(wtap_rec *rec, uint8_t *pd)
{
        unsigned packet_size;
        struct pfloghdr *pflhdr;

        /*
         * Minimum of captured and actual length (just in case the
         * actual length < the captured length, which Should Never
         * Happen).
         */
        packet_size = rec->rec_header.packet_header.caplen;
        if (packet_size > rec->rec_header.packet_header.len)
                packet_size = rec->rec_header.packet_header.len;

        if (packet_size < sizeof(struct pfloghdr)) {
                /* Not enough data to have the UID and PID fields */
                return;
        }

        pflhdr = (struct pfloghdr *)pd;
        if (pflhdr->length < (unsigned) (offsetof(struct pfloghdr, rule_pid) + sizeof pflhdr->rule_pid)) {
                /* Header doesn't include the UID and PID fields */
                return;
        }
        PBSWAP32((uint8_t *)&pflhdr->uid);
        PBSWAP32((uint8_t *)&pflhdr->pid);
        PBSWAP32((uint8_t *)&pflhdr->rule_uid);
        PBSWAP32((uint8_t *)&pflhdr->rule_pid);
}

int
pcap_process_pseudo_header(FILE_T fh, bool is_nokia, int wtap_encap,
    unsigned packet_size, wtap_rec *rec, int *err, char **err_info)
{
        int phdr_len = 0;

        switch (wtap_encap) {

        case WTAP_ENCAP_ATM_PDUS:
                if (is_nokia) {
                        /*
                         * Nokia IPSO ATM.
                         */
                        phdr_len = pcap_read_nokiaatm_pseudoheader(fh,
                            &rec->rec_header.packet_header.pseudo_header,
                            packet_size, err, err_info);
                        if (phdr_len == -1)
                                return -1;      /* Read error */
                } else {
                        /*
                         * SunATM.
                         */
                        phdr_len = pcap_read_sunatm_pseudoheader(fh,
                            &rec->rec_header.packet_header.pseudo_header,
                            packet_size, err, err_info);
                        if (phdr_len == -1)
                                return -1;      /* Read error */
                }
                break;

        case WTAP_ENCAP_ETHERNET:
                if (is_nokia) {
                        /*
                         * Nokia IPSO.  Pseudo 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, &rec->rec_header.packet_header.pseudo_header, err, err_info))
                                return -1;      /* Read error */
                }

                /*
                 * We don't know whether there's an FCS in this frame or not.
                 */
                rec->rec_header.packet_header.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,
                 * at least in pcap files.  For radiotap, that's indicated in
                 * the radiotap header.
                 *
                 * XXX - in pcapng, there *could* be a packet option
                 * indicating the FCS length.
                 */
                memset(&rec->rec_header.packet_header.pseudo_header.ieee_802_11, 0, sizeof(rec->rec_header.packet_header.pseudo_header.ieee_802_11));
                rec->rec_header.packet_header.pseudo_header.ieee_802_11.fcs_len = -1;
                rec->rec_header.packet_header.pseudo_header.ieee_802_11.decrypted = false;
                rec->rec_header.packet_header.pseudo_header.ieee_802_11.datapad = false;
                break;

        case WTAP_ENCAP_IRDA:
                phdr_len = pcap_read_irda_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_MTP2_WITH_PHDR:
                phdr_len = pcap_read_mtp2_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_LINUX_LAPD:
                phdr_len = pcap_read_lapd_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_SITA:
                phdr_len = pcap_read_sita_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

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

        case WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR:
                phdr_len = pcap_read_bt_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_BLUETOOTH_LINUX_MONITOR:
                phdr_len = pcap_read_bt_monitor_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_NFC_LLCP:
                phdr_len = pcap_read_llcp_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_PPP_WITH_PHDR:
                phdr_len = pcap_read_ppp_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_ERF:
                phdr_len = pcap_read_erf_pseudoheader(fh, rec,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;

        case WTAP_ENCAP_I2C_LINUX:
                phdr_len = pcap_read_i2c_linux_pseudoheader(fh,
                    &rec->rec_header.packet_header.pseudo_header,
                    packet_size, err, err_info);
                if (phdr_len == -1)
                        return -1;      /* Read error */
                break;
        }

        return phdr_len;
}

/*
 * Compute, from the data provided by the Linux USB memory-mapped capture
 * mechanism, the amount of packet data that would have been provided
 * had the capture mechanism not chopped off any data at the end, if, in
 * fact, it did so.
 *
 * Set the "unsliced length" field of the packet header to that value.
 */
static void
fix_linux_usb_mmapped_length(wtap_rec *rec, const u_char *bp)
{
        const struct linux_usb_phdr *hdr;
        u_int bytes_left;

        /*
         * All callers of this routine must ensure that pkth->caplen is
         * >= sizeof (struct linux_usb_phdr).
         */
        bytes_left = rec->rec_header.packet_header.caplen;
        bytes_left -= sizeof (struct linux_usb_phdr);

        hdr = (const struct linux_usb_phdr *) bp;
        if (!hdr->data_flag && hdr->transfer_type == URB_ISOCHRONOUS &&
            hdr->event_type == URB_COMPLETE &&
            (hdr->endpoint_number & URB_TRANSFER_IN) &&
            rec->rec_header.packet_header.len == sizeof(struct linux_usb_phdr) +
                         (hdr->ndesc * sizeof (struct linux_usb_isodesc)) + hdr->urb_len) {
                struct linux_usb_isodesc *descs;
                u_int pre_truncation_data_len, pre_truncation_len;

                descs = (struct linux_usb_isodesc *) (bp + sizeof(struct linux_usb_phdr));

                /*
                 * We have data (yes, data_flag is 0 if we *do* have data),
                 * and this is a "this is complete" incoming isochronous
                 * transfer event, and the length was calculated based
                 * on the URB length.
                 *
                 * That's not correct, because the data isn't contiguous,
                 * and the isochronous descriptos show how it's scattered.
                 *
                 * Find the end of the last chunk of data in the buffer
                 * referred to by the isochronous descriptors; that indicates
                 * how far into the buffer the data would have gone.
                 *
                 * Make sure we don't run past the end of the captured data
                 * while processing the isochronous descriptors.
                 */
                pre_truncation_data_len = 0;
                for (uint32_t desc = 0;
                    desc < hdr->ndesc && bytes_left >= sizeof (struct linux_usb_isodesc);
                    desc++, bytes_left -= sizeof (struct linux_usb_isodesc)) {
                        u_int desc_end;

                        if (descs[desc].iso_len != 0) {
                                desc_end = descs[desc].iso_off + descs[desc].iso_len;
                                if (desc_end > pre_truncation_data_len)
                                        pre_truncation_data_len = desc_end;
                        }
                }

                /*
                 * Now calculate the total length based on that data
                 * length.
                 */
                pre_truncation_len = sizeof(struct linux_usb_phdr) +
                    (hdr->ndesc * sizeof (struct linux_usb_isodesc)) +
                    pre_truncation_data_len;

                /*
                 * If that's greater than or equal to the captured length,
                 * use that as the length.
                 */
                if (pre_truncation_len >= rec->rec_header.packet_header.caplen)
                        rec->rec_header.packet_header.len = pre_truncation_len;

                /*
                 * If the captured length is greater than the length,
                 * use the captured length.
                 *
                 * For completion events for incoming isochronous transfers,
                 * it's based on data_len, which is calculated the same way
                 * we calculated pre_truncation_data_len above, except that
                 * it has access to all the isochronous descriptors, not
                 * just the ones that the kernel were able to provide us or,
                 * for a capture file, that weren't sliced off by a snapshot
                 * length.
                 *
                 * However, it might have been reduced by the USB capture
                 * mechanism arbitrarily limiting the amount of data it
                 * provides to userland, or by the libpcap capture code
                 * limiting it to being no more than the snapshot, so
                 * we don't want to just use it all the time; we only
                 * do so to try to get a better estimate of the actual
                 * length - and to make sure the on-the-network length
                 * is always >= the captured length.
                 */
                if (rec->rec_header.packet_header.caplen > rec->rec_header.packet_header.len)
                        rec->rec_header.packet_header.len = rec->rec_header.packet_header.caplen;
        }
}

static void
pcap_fixup_len(wtap_rec *rec, const uint8_t *pd)
{
        struct linux_usb_phdr *usb_phdr;

        /*
         * Greasy hack, but we never directly dereference any of
         * the fields in *usb_phdr, we just get offsets of and
         * addresses of its members and byte-swap it with a
         * byte-at-a-time macro, so it's alignment-safe.
         */
        usb_phdr = (struct linux_usb_phdr *)(void *)pd;

        if (rec->rec_header.packet_header.caplen >=
            sizeof (struct linux_usb_phdr)) {
                /*
                 * In older versions of libpcap, in memory-mapped captures,
                 * the "on-the-bus length" for completion events for
                 * incoming isochronous transfers was miscalculated; it
                 * needed to be calculated based on the* offsets and lengths
                 * in the descriptors, not on the raw URB length, but it
                 * wasn't.
                 *
                 * If this packet contains transferred data (yes, data_flag
                 * is 0 if we *do* have data), and the total on-the-network
                 * length is equal to the value calculated from the raw URB
                 * length, then it might be one of those transfers.
                 *
                 * We only do this if we have the full USB pseudo-header.
                 */
                if (!usb_phdr->data_flag &&
                    rec->rec_header.packet_header.len == sizeof (struct linux_usb_phdr) +
                      (usb_phdr->ndesc * sizeof (struct linux_usb_isodesc)) + usb_phdr->urb_len) {
                        /*
                         * It might need fixing; fix it if it's a completion
                         * event for an incoming isochronous transfer.
                         */
                        fix_linux_usb_mmapped_length(rec, pd);
                }
        }
}

void
pcap_read_post_process(bool is_nokia, int wtap_encap,
    wtap_rec *rec, uint8_t *pd, bool bytes_swapped, int fcs_len)
{
        switch (wtap_encap) {

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

        case WTAP_ENCAP_ETHERNET:
                /*
                 * The FCS length is supposed to be in bits.
                 * If it's < 8, assume it's in bytes; otherwise,
                 * convert it to bytes.
                 */
                if (fcs_len < 8)
                        rec->rec_header.packet_header.pseudo_header.eth.fcs_len = fcs_len;
                else
                        rec->rec_header.packet_header.pseudo_header.eth.fcs_len = fcs_len/8;
                break;

        case WTAP_ENCAP_SLL:
                if (bytes_swapped)
                        pcap_byteswap_linux_sll_pseudoheader(rec, pd);
                break;

        case WTAP_ENCAP_SLL2:
                if (bytes_swapped)
                        pcap_byteswap_linux_sll2_pseudoheader(rec, pd);
                break;

        case WTAP_ENCAP_USB_LINUX:
                if (bytes_swapped)
                        pcap_byteswap_linux_usb_pseudoheader(rec, pd, false);
                break;

        case WTAP_ENCAP_USB_LINUX_MMAPPED:
                if (bytes_swapped)
                        pcap_byteswap_linux_usb_pseudoheader(rec, pd, true);

                /*
                 * Fix up the on-the-network length if necessary.
                 */
                pcap_fixup_len(rec, 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.
                 */
                rec->rec_header.packet_header.pseudo_header.eth.fcs_len = 4;
                break;

        case WTAP_ENCAP_NFLOG:
                if (bytes_swapped)
                        pcap_byteswap_nflog_pseudoheader(rec, pd);
                break;

        case WTAP_ENCAP_ERF:
                /*
                 * Update packet size to account for ERF padding and snapping.
                 * Captured length is minimum of wlen and previously calculated
                 * caplen (which would have included padding but not phdr).
                 */
                rec->rec_header.packet_header.len = rec->rec_header.packet_header.pseudo_header.erf.phdr.wlen;
                rec->rec_header.packet_header.caplen = MIN(rec->rec_header.packet_header.len, rec->rec_header.packet_header.caplen);
                break;

        case WTAP_ENCAP_PFLOG:
                if (bytes_swapped)
                        pcap_byteswap_pflog_pseudoheader(rec, pd);
                break;

        default:
                break;
        }
}

bool
wtap_encap_requires_phdr(int wtap_encap)
{
        switch (wtap_encap) {

        case WTAP_ENCAP_ATM_PDUS:
        case WTAP_ENCAP_IRDA:
        case WTAP_ENCAP_MTP2_WITH_PHDR:
        case WTAP_ENCAP_LINUX_LAPD:
        case WTAP_ENCAP_SITA:
        case WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR:
        case WTAP_ENCAP_BLUETOOTH_LINUX_MONITOR:
        case WTAP_ENCAP_NFC_LLCP:
        case WTAP_ENCAP_PPP_WITH_PHDR:
        case WTAP_ENCAP_ERF:
        case WTAP_ENCAP_I2C_LINUX:
                return true;
        }
        return false;
}

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_BLUETOOTH_H4_WITH_PHDR:
                hdrsize = (int)sizeof (struct pcap_bt_phdr);
                break;

        case WTAP_ENCAP_BLUETOOTH_LINUX_MONITOR:
                hdrsize = (int)sizeof (struct pcap_bt_monitor_phdr);
                break;

        case WTAP_ENCAP_NFC_LLCP:
                hdrsize = LLCP_HEADER_LEN;
                break;

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

        case WTAP_ENCAP_ERF:
                hdrsize = (int)sizeof (struct erf_phdr);

                /*
                 * If the type of record given in the pseudo header
                 * indicates the presence of an extension header, then
                 * add in the lengths of the extension headers.
                 */
                if (pseudo_header->erf.phdr.type & 0x80) {
                        int i = 0, max = array_length(pseudo_header->erf.ehdr_list);
                        uint8_t erf_exhdr[8];
                        uint8_t type;

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

                /*
                 * Now add in the length of the subheader, if any.
                 */
                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_AAL2:
                        hdrsize += (int)sizeof(struct erf_aal2_hdr);
                        break;

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

                default:
                        break;
                }
                break;

        case WTAP_ENCAP_I2C_LINUX:
                hdrsize = (int)sizeof (struct i2c_linux_file_hdr);
                break;

        default:
                hdrsize = 0;
                break;
        }

        return hdrsize;
}

bool
pcap_write_phdr(wtap_dumper *wdh, int encap, const union wtap_pseudo_header *pseudo_header,
    int *err)
{
        switch (encap) {

        case WTAP_ENCAP_ATM_PDUS:
                if (!pcap_write_sunatm_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_IRDA:
                if (!pcap_write_irda_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_MTP2_WITH_PHDR:
                if (!pcap_write_mtp2_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_LINUX_LAPD:
                if (!pcap_write_lapd_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_SITA:
                if (!pcap_write_sita_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_BLUETOOTH_H4_WITH_PHDR:
                if (!pcap_write_bt_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_BLUETOOTH_LINUX_MONITOR:
                if (!pcap_write_bt_monitor_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_NFC_LLCP:
                if (!pcap_write_llcp_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_PPP_WITH_PHDR:
                if (!pcap_write_ppp_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_ERF:
                if (!pcap_write_erf_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;

        case WTAP_ENCAP_I2C_LINUX:
                if (!pcap_write_i2c_linux_pseudoheader(wdh, pseudo_header, err))
                        return false;
                break;
        }
        return true;
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */