* Copyright (c) 1993, 1994, 1995, 1996, 1997

/* $NetBSD: pcap-common.c,v 1.9 2024/09/02 15:33:37 christos Exp $ */

/*
* Copyright (c) 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* pcap-common.c - common code for pcap and pcapng files
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: pcap-common.c,v 1.9 2024/09/02 15:33:37 christos Exp $");

#include <config.h>

#include <pcap-types.h>

#include "pcap-int.h"

#include "pcap-common.h"

/*
* We don't write DLT_* values to capture files, because they're not the
* same on all platforms.
*
* Unfortunately, the various flavors of BSD have not always used the same
* numerical values for the same data types, and various patches to
* libpcap for non-BSD OSes have added their own DLT_* codes for link
* layer encapsulation types seen on those OSes, and those codes have had,
* in some cases, values that were also used, on other platforms, for other
* link layer encapsulation types.
*
* This means that capture files of a type whose numerical DLT_* code
* means different things on different BSDs, or with different versions
* of libpcap, can't always be read on systems other than those like
* the one running on the machine on which the capture was made.
*
* Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
* to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
* codes to DLT_* codes when reading a savefile header.
*
* For those DLT_* codes that have, as far as we know, the same values on
* all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
* DLT_xxx; that way, captures of those types can still be read by
* versions of libpcap that map LINKTYPE_* values to DLT_* values, and
* captures of those types written by versions of libpcap that map DLT_
* values to LINKTYPE_ values can still be read by older versions
* of libpcap.
*
* The other LINKTYPE_* codes are given values starting at 100, in the
* hopes that no DLT_* code will be given one of those values.
*
* In order to ensure that a given LINKTYPE_* code's value will refer to
* the same encapsulation type on all platforms, you should not allocate
* a new LINKTYPE_* value without consulting
* "[email protected]". The tcpdump developers will
* allocate a value for you, and will not subsequently allocate it to
* anybody else; that value will be added to the "pcap.h" in the
* tcpdump.org Git repository, so that a future libpcap release will
* include it.
*
* You should, if possible, also contribute patches to libpcap and tcpdump
* to handle the new encapsulation type, so that they can also be checked
* into the tcpdump.org Git repository and so that they will appear in
* future libpcap and tcpdump releases.
*
* Do *NOT* assume that any values after the largest value in this file
* are available; you might not have the most up-to-date version of this
* file, and new values after that one might have been assigned. Also,
* do *NOT* use any values below 100 - those might already have been
* taken by one (or more!) organizations.
*
* Any platform that defines additional DLT_* codes should:
*
* request a LINKTYPE_* code and value from tcpdump.org,
* as per the above;
*
* add, in their version of libpcap, an entry to map
* those DLT_* codes to the corresponding LINKTYPE_*
* code;
*
* redefine, in their "net/bpf.h", any DLT_* values
* that collide with the values used by their additional
* DLT_* codes, to remove those collisions (but without
* making them collide with any of the LINKTYPE_*
* values equal to 50 or above; they should also avoid
* defining DLT_* values that collide with those
* LINKTYPE_* values, either).
*/

/*
* These values the DLT_ values for which are the same on all platforms,
* and that have been defined by <net/bpf.h> for ages.
*
* For those, the LINKTYPE_ values are equal to the DLT_ values.
*
* LINKTYPE_LOW_MATCHING_MIN is the lowest such value;
* LINKTYPE_LOW_MATCHING_MAX is the highest such value.
*/
#define LINKTYPE_LOW_MATCHING_MIN 0 /* lowest value in this "matching" range */
#define LINKTYPE_NULL DLT_NULL
#define LINKTYPE_ETHERNET DLT_EN10MB /* also for 100Mb and up */
#define LINKTYPE_EXP_ETHERNET DLT_EN3MB /* 3Mb experimental Ethernet */
#define LINKTYPE_AX25 DLT_AX25
#define LINKTYPE_PRONET DLT_PRONET
#define LINKTYPE_CHAOS DLT_CHAOS
#define LINKTYPE_IEEE802_5 DLT_IEEE802 /* DLT_IEEE802 is used for 802.5 Token Ring */
#define LINKTYPE_ARCNET_BSD DLT_ARCNET /* BSD-style headers */
#define LINKTYPE_SLIP DLT_SLIP
#define LINKTYPE_PPP DLT_PPP
#define LINKTYPE_FDDI DLT_FDDI

#define LINKTYPE_LOW_MATCHING_MAX LINKTYPE_FDDI /* highest value in this "matching" range */

/*
* LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
* PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
* field) at the beginning of the packet.
*
* This is for use when there is always such a header; the address field
* might be 0xff, for regular PPP, or it might be an address field for Cisco
* point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
* HDLC"). This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
*
* We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
* nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
* captures will be written out with a link type that NetBSD's tcpdump
* can read.
*/
#define LINKTYPE_PPP_HDLC 50 /* PPP in HDLC-like framing */

#define LINKTYPE_PPP_ETHER 51 /* NetBSD PPP-over-Ethernet */

#define LINKTYPE_SYMANTEC_FIREWALL 99 /* Symantec Enterprise Firewall */

/*
* These correspond to DLT_s that have different values on different
* platforms; we map between these values in capture files and
* the DLT_ values as returned by pcap_datalink() and passed to
* pcap_open_dead().
*/
#define LINKTYPE_ATM_RFC1483 100 /* LLC/SNAP-encapsulated ATM */
#define LINKTYPE_RAW 101 /* raw IP */
#define LINKTYPE_SLIP_BSDOS 102 /* BSD/OS SLIP BPF header */
#define LINKTYPE_PPP_BSDOS 103 /* BSD/OS PPP BPF header */

/*
* Values starting with 104 are used for newly-assigned link-layer
* header type values; for those link-layer header types, the DLT_
* value returned by pcap_datalink() and passed to pcap_open_dead(),
* and the LINKTYPE_ value that appears in capture files, are the
* same.
*
* LINKTYPE_HIGH_MATCHING_MIN is the lowest such value;
* LINKTYPE_HIGH_MATCHING_MAX is the highest such value.
*/
#define LINKTYPE_HIGH_MATCHING_MIN 104 /* lowest value in the "matching" range */

#define LINKTYPE_C_HDLC 104 /* Cisco HDLC */
#define LINKTYPE_IEEE802_11 105 /* IEEE 802.11 (wireless) */
#define LINKTYPE_ATM_CLIP 106 /* Linux Classical IP over ATM */
#define LINKTYPE_FRELAY 107 /* Frame Relay */
#define LINKTYPE_LOOP 108 /* OpenBSD loopback */
#define LINKTYPE_ENC 109 /* OpenBSD IPSEC enc */

/*
* These two types are reserved for future use.
*/
#define LINKTYPE_LANE8023 110 /* ATM LANE + 802.3 */
#define LINKTYPE_HIPPI 111 /* NetBSD HIPPI */

/*
* Used for NetBSD DLT_HDLC; from looking at the one driver in NetBSD
* that uses it, it's Cisco HDLC, so it's the same as DLT_C_HDLC/
* LINKTYPE_C_HDLC, but we define a separate value to avoid some
* compatibility issues with programs on NetBSD.
*
* All code should treat LINKTYPE_NETBSD_HDLC and LINKTYPE_C_HDLC the same.
*/
#define LINKTYPE_NETBSD_HDLC 112 /* NetBSD HDLC framing */

#define LINKTYPE_LINUX_SLL 113 /* Linux cooked socket capture */
#define LINKTYPE_LTALK 114 /* Apple LocalTalk hardware */
#define LINKTYPE_ECONET 115 /* Acorn Econet */

/*
* Reserved for use with OpenBSD ipfilter.
*/
#define LINKTYPE_IPFILTER 116

#define LINKTYPE_PFLOG 117 /* OpenBSD DLT_PFLOG */
#define LINKTYPE_CISCO_IOS 118 /* For Cisco-internal use */
#define LINKTYPE_IEEE802_11_PRISM 119 /* 802.11 plus Prism II monitor mode radio metadata header */
#define LINKTYPE_IEEE802_11_AIRONET 120 /* 802.11 plus FreeBSD Aironet driver radio metadata header */

/*
* Reserved for Siemens HiPath HDLC.
*/
#define LINKTYPE_HHDLC 121

#define LINKTYPE_IP_OVER_FC 122 /* RFC 2625 IP-over-Fibre Channel */
#define LINKTYPE_SUNATM 123 /* Solaris+SunATM */

/*
* Reserved as per request from Kent Dahlgren <[email protected]>
* for private use.
*/
#define LINKTYPE_RIO 124 /* RapidIO */
#define LINKTYPE_PCI_EXP 125 /* PCI Express */
#define LINKTYPE_AURORA 126 /* Xilinx Aurora link layer */

#define LINKTYPE_IEEE802_11_RADIOTAP 127 /* 802.11 plus radiotap radio metadata header */

/*
* Reserved for the TZSP encapsulation, as per request from
* Chris Waters <[email protected]>
* TZSP is a generic encapsulation for any other link type,
* which includes a means to include meta-information
* with the packet, e.g. signal strength and channel
* for 802.11 packets.
*/
#define LINKTYPE_TZSP 128 /* Tazmen Sniffer Protocol */

#define LINKTYPE_ARCNET_LINUX 129 /* Linux-style headers */

/*
* Juniper-private data link types, as per request from
* Hannes Gredler <[email protected]>. The corresponding
* DLT_s are used for passing on chassis-internal
* metainformation such as QOS profiles, etc..
*/
#define LINKTYPE_JUNIPER_MLPPP 130
#define LINKTYPE_JUNIPER_MLFR 131
#define LINKTYPE_JUNIPER_ES 132
#define LINKTYPE_JUNIPER_GGSN 133
#define LINKTYPE_JUNIPER_MFR 134
#define LINKTYPE_JUNIPER_ATM2 135
#define LINKTYPE_JUNIPER_SERVICES 136
#define LINKTYPE_JUNIPER_ATM1 137

#define LINKTYPE_APPLE_IP_OVER_IEEE1394 138 /* Apple IP-over-IEEE 1394 cooked header */

#define LINKTYPE_MTP2_WITH_PHDR 139
#define LINKTYPE_MTP2 140
#define LINKTYPE_MTP3 141
#define LINKTYPE_SCCP 142

#define LINKTYPE_DOCSIS 143 /* DOCSIS MAC frames */

#define LINKTYPE_LINUX_IRDA 144 /* Linux-IrDA */

/*
* Reserved for IBM SP switch and IBM Next Federation switch.
*/
#define LINKTYPE_IBM_SP 145
#define LINKTYPE_IBM_SN 146

/*
* Reserved for private use. If you have some link-layer header type
* that you want to use within your organization, with the capture files
* using that link-layer header type not ever be sent outside your
* organization, you can use these values.
*
* No libpcap release will use these for any purpose, nor will any
* tcpdump release use them, either.
*
* Do *NOT* use these in capture files that you expect anybody not using
* your private versions of capture-file-reading tools to read; in
* particular, do *NOT* use them in products, otherwise you may find that
* people won't be able to use tcpdump, or snort, or Ethereal, or... to
* read capture files from your firewall/intrusion detection/traffic
* monitoring/etc. appliance, or whatever product uses that LINKTYPE_ value,
* and you may also find that the developers of those applications will
* not accept patches to let them read those files.
*
* Also, do not use them if somebody might send you a capture using them
* for *their* private type and tools using them for *your* private type
* would have to read them.
*
* Instead, in those cases, ask "[email protected]" for a
* new DLT_ and LINKTYPE_ value, as per the comment in pcap/bpf.h, and use
* the type you're given.
*/
#define LINKTYPE_USER0 147
#define LINKTYPE_USER1 148
#define LINKTYPE_USER2 149
#define LINKTYPE_USER3 150
#define LINKTYPE_USER4 151
#define LINKTYPE_USER5 152
#define LINKTYPE_USER6 153
#define LINKTYPE_USER7 154
#define LINKTYPE_USER8 155
#define LINKTYPE_USER9 156
#define LINKTYPE_USER10 157
#define LINKTYPE_USER11 158
#define LINKTYPE_USER12 159
#define LINKTYPE_USER13 160
#define LINKTYPE_USER14 161
#define LINKTYPE_USER15 162

/*
* For future use with 802.11 captures - defined by AbsoluteValue
* Systems to store a number of bits of link-layer information
* including radio information:
*
* http://www.shaftnet.org/~pizza/software/capturefrm.txt
*/
#define LINKTYPE_IEEE802_11_AVS 163 /* 802.11 plus AVS radio metadata header */

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>. The corresponding
* DLT_s are used for passing on chassis-internal
* metainformation such as QOS profiles, etc..
*/
#define LINKTYPE_JUNIPER_MONITOR 164

/*
* BACnet MS/TP frames.
*/
#define LINKTYPE_BACNET_MS_TP 165

/*
* Another PPP variant as per request from Karsten Keil <[email protected]>.
*
* This is used in some OSes to allow a kernel socket filter to distinguish
* between incoming and outgoing packets, on a socket intended to
* supply pppd with outgoing packets so it can do dial-on-demand and
* hangup-on-lack-of-demand; incoming packets are filtered out so they
* don't cause pppd to hold the connection up (you don't want random
* input packets such as port scans, packets from old lost connections,
* etc. to force the connection to stay up).
*
* The first byte of the PPP header (0xff03) is modified to accommodate
* the direction - 0x00 = IN, 0x01 = OUT.
*/
#define LINKTYPE_PPP_PPPD 166

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>. The DLT_s are used
* for passing on chassis-internal metainformation such as
* QOS profiles, cookies, etc..
*/
#define LINKTYPE_JUNIPER_PPPOE 167
#define LINKTYPE_JUNIPER_PPPOE_ATM 168

#define LINKTYPE_GPRS_LLC 169 /* GPRS LLC */
#define LINKTYPE_GPF_T 170 /* GPF-T (ITU-T G.7041/Y.1303) */
#define LINKTYPE_GPF_F 171 /* GPF-F (ITU-T G.7041/Y.1303) */

/*
* Requested by Oolan Zimmer <[email protected]> for use in Gcom's T1/E1 line
* monitoring equipment.
*/
#define LINKTYPE_GCOM_T1E1 172
#define LINKTYPE_GCOM_SERIAL 173

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>. The DLT_ is used
* for internal communication to Physical Interface Cards (PIC)
*/
#define LINKTYPE_JUNIPER_PIC_PEER 174

/*
* Link types requested by Gregor Maier <[email protected]> of Endace
* Measurement Systems. They add an ERF header (see
* https://www.endace.com/support/EndaceRecordFormat.pdf) in front of
* the link-layer header.
*/
#define LINKTYPE_ERF_ETH 175 /* Ethernet */
#define LINKTYPE_ERF_POS 176 /* Packet-over-SONET */

/*
* Requested by Daniele Orlandi <[email protected]> for raw LAPD
* for vISDN (http://www.orlandi.com/visdn/). Its link-layer header
* includes additional information before the LAPD header, so it's
* not necessarily a generic LAPD header.
*/
#define LINKTYPE_LINUX_LAPD 177

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>.
* The Link Types are used for prepending meta-information
* like interface index, interface name
* before standard Ethernet, PPP, Frelay & C-HDLC Frames
*/
#define LINKTYPE_JUNIPER_ETHER 178
#define LINKTYPE_JUNIPER_PPP 179
#define LINKTYPE_JUNIPER_FRELAY 180
#define LINKTYPE_JUNIPER_CHDLC 181

/*
* Multi Link Frame Relay (FRF.16)
*/
#define LINKTYPE_MFR 182

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>.
* The DLT_ is used for internal communication with a
* voice Adapter Card (PIC)
*/
#define LINKTYPE_JUNIPER_VP 183

/*
* Arinc 429 frames.
* DLT_ requested by Gianluca Varenni <[email protected]>.
* Every frame contains a 32bit A429 label.
* More documentation on Arinc 429 can be found at
* https://web.archive.org/web/20040616233302/https://www.condoreng.com/support/downloads/tutorials/ARINCTutorial.pdf
*/
#define LINKTYPE_A429 184

/*
* Arinc 653 Interpartition Communication messages.
* DLT_ requested by Gianluca Varenni <[email protected]>.
* Please refer to the A653-1 standard for more information.
*/
#define LINKTYPE_A653_ICM 185

/*
* This used to be "USB packets, beginning with a USB setup header;
* requested by Paolo Abeni <[email protected]>."
*
* However, that header didn't work all that well - it left out some
* useful information - and was abandoned in favor of the DLT_USB_LINUX
* header.
*
* This is now used by FreeBSD for its BPF taps for USB; that has its
* own headers. So it is written, so it is done.
*/
#define LINKTYPE_USB_FREEBSD 186

/*
* Bluetooth HCI UART transport layer (part H:4); requested by
* Paolo Abeni.
*/
#define LINKTYPE_BLUETOOTH_HCI_H4 187

/*
* IEEE 802.16 MAC Common Part Sublayer; requested by Maria Cruz
* <[email protected]>.
*/
#define LINKTYPE_IEEE802_16_MAC_CPS 188

/*
* USB packets, beginning with a Linux USB header; requested by
* Paolo Abeni <[email protected]>.
*/
#define LINKTYPE_USB_LINUX 189

/*
* Controller Area Network (CAN) v. 2.0B packets.
* DLT_ requested by Gianluca Varenni <[email protected]>.
* Used to dump CAN packets coming from a CAN Vector board.
* More documentation on the CAN v2.0B frames can be found at
* http://www.can-cia.org/downloads/?269
*/
#define LINKTYPE_CAN20B 190

/*
* IEEE 802.15.4, with address fields padded, as is done by Linux
* drivers; requested by Juergen Schimmer.
*/
#define LINKTYPE_IEEE802_15_4_LINUX 191

/*
* Per Packet Information encapsulated packets.
* LINKTYPE_ requested by Gianluca Varenni <[email protected]>.
*/
#define LINKTYPE_PPI 192

/*
* Header for 802.16 MAC Common Part Sublayer plus a radiotap radio header;
* requested by Charles Clancy.
*/
#define LINKTYPE_IEEE802_16_MAC_CPS_RADIO 193

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>.
* The DLT_ is used for internal communication with a
* integrated service module (ISM).
*/
#define LINKTYPE_JUNIPER_ISM 194

/*
* IEEE 802.15.4, exactly as it appears in the spec (no padding, no
* nothing), and with the FCS at the end of the frame; requested by
* Mikko Saarnivala <[email protected]>.
*
* This should only be used if the FCS is present at the end of the
* frame; if the frame has no FCS, DLT_IEEE802_15_4_NOFCS should be
* used.
*/
#define LINKTYPE_IEEE802_15_4_WITHFCS 195

/*
* Various link-layer types, with a pseudo-header, for SITA
* (https://www.sita.aero/); requested by Fulko Hew ([email protected]).
*/
#define LINKTYPE_SITA 196

/*
* Various link-layer types, with a pseudo-header, for Endace DAG cards;
* encapsulates Endace ERF records. Requested by Stephen Donnelly
* <[email protected]>.
*/
#define LINKTYPE_ERF 197

/*
* Special header prepended to Ethernet packets when capturing from a
* u10 Networks board. Requested by Phil Mulholland
* <[email protected]>.
*/
#define LINKTYPE_RAIF1 198

/*
* IPMB packet for IPMI, beginning with a 2-byte header, followed by
* the I2C slave address, followed by the netFn and LUN, etc..
* Requested by Chanthy Toeung <[email protected]>.
*
* XXX - its DLT_ value used to be called DLT_IPMB, back when we got the
* impression from the email thread requesting it that the packet
* had no extra 2-byte header. We've renamed it; if anybody used
* DLT_IPMB and assumed no 2-byte header, this will cause the compile
* to fail, at which point we'll have to figure out what to do about
* the two header types using the same DLT_/LINKTYPE_ value. If that
* doesn't happen, we'll assume nobody used it and that the redefinition
* is safe.
*/
#define LINKTYPE_IPMB_KONTRON 199

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>.
* The DLT_ is used for capturing data on a secure tunnel interface.
*/
#define LINKTYPE_JUNIPER_ST 200

/*
* Bluetooth HCI UART transport layer (part H:4), with pseudo-header
* that includes direction information; requested by Paolo Abeni.
*/
#define LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR 201

/*
* AX.25 packet with a 1-byte KISS header; see
*
* http://www.ax25.net/kiss.htm
*
* as per Richard Stearn <[email protected]>.
*/
#define LINKTYPE_AX25_KISS 202

/*
* LAPD packets from an ISDN channel, starting with the address field,
* with no pseudo-header.
* Requested by Varuna De Silva <[email protected]>.
*/
#define LINKTYPE_LAPD 203

/*
* PPP, with a one-byte direction pseudo-header prepended - zero means
* "received by this host", non-zero (any non-zero value) means "sent by
* this host" - as per Will Barker <[email protected]>.
*/
#define LINKTYPE_PPP_WITH_DIR 204 /* Don't confuse with LINKTYPE_PPP_PPPD */

/*
* Cisco HDLC, with a one-byte direction pseudo-header prepended - zero
* means "received by this host", non-zero (any non-zero value) means
* "sent by this host" - as per Will Barker <[email protected]>.
*/
#define LINKTYPE_C_HDLC_WITH_DIR 205 /* Cisco HDLC */

/*
* Frame Relay, with a one-byte direction pseudo-header prepended - zero
* means "received by this host" (DCE -> DTE), non-zero (any non-zero
* value) means "sent by this host" (DTE -> DCE) - as per Will Barker
* <[email protected]>.
*/
#define LINKTYPE_FRELAY_WITH_DIR 206 /* Frame Relay */

/*
* LAPB, with a one-byte direction pseudo-header prepended - zero means
* "received by this host" (DCE -> DTE), non-zero (any non-zero value)
* means "sent by this host" (DTE -> DCE)- as per Will Barker
* <[email protected]>.
*/
#define LINKTYPE_LAPB_WITH_DIR 207 /* LAPB */

/*
* 208 is reserved for an as-yet-unspecified proprietary link-layer
* type, as requested by Will Barker.
*/

/*
* IPMB with a Linux-specific pseudo-header; as requested by Alexey Neyman
* <[email protected]>.
*/
#define LINKTYPE_IPMB_LINUX 209

/*
* FlexRay automotive bus - http://www.flexray.com/ - as requested
* by Hannes Kaelber <[email protected]>.
*/
#define LINKTYPE_FLEXRAY 210

/*
* Media Oriented Systems Transport (MOST) bus for multimedia
* transport - https://www.mostcooperation.com/ - as requested
* by Hannes Kaelber <[email protected]>.
*/
#define LINKTYPE_MOST 211

/*
* Local Interconnect Network (LIN) bus for vehicle networks -
* http://www.lin-subbus.org/ - as requested by Hannes Kaelber
* <[email protected]>.
*/
#define LINKTYPE_LIN 212

/*
* X2E-private data link type used for serial line capture,
* as requested by Hannes Kaelber <[email protected]>.
*/
#define LINKTYPE_X2E_SERIAL 213

/*
* X2E-private data link type used for the Xoraya data logger
* family, as requested by Hannes Kaelber <[email protected]>.
*/
#define LINKTYPE_X2E_XORAYA 214

/*
* IEEE 802.15.4, exactly as it appears in the spec (no padding, no
* nothing), but with the PHY-level data for non-ASK PHYs (4 octets
* of 0 as preamble, one octet of SFD, one octet of frame length+
* reserved bit, and then the MAC-layer data, starting with the
* frame control field).
*
* Requested by Max Filippov <[email protected]>.
*/
#define LINKTYPE_IEEE802_15_4_NONASK_PHY 215

/*
* David Gibson <[email protected]> requested this for
* captures from the Linux kernel /dev/input/eventN devices. This
* is used to communicate keystrokes and mouse movements from the
* Linux kernel to display systems, such as Xorg.
*/
#define LINKTYPE_LINUX_EVDEV 216

/*
* GSM Um and Abis interfaces, preceded by a "gsmtap" header.
*
* Requested by Harald Welte <[email protected]>.
*/
#define LINKTYPE_GSMTAP_UM 217
#define LINKTYPE_GSMTAP_ABIS 218

/*
* MPLS, with an MPLS label as the link-layer header.
* Requested by Michele Marchetto <[email protected]> on behalf
* of OpenBSD.
*/
#define LINKTYPE_MPLS 219

/*
* USB packets, beginning with a Linux USB header, with the USB header
* padded to 64 bytes; required for memory-mapped access.
*/
#define LINKTYPE_USB_LINUX_MMAPPED 220

/*
* DECT packets, with a pseudo-header; requested by
* Matthias Wenzel <[email protected]>.
*/
#define LINKTYPE_DECT 221

/*
* From: "Lidwa, Eric (GSFC-582.0)[SGT INC]" <[email protected]>
* Date: Mon, 11 May 2009 11:18:30 -0500
*
* DLT_AOS. We need it for AOS Space Data Link Protocol.
* I have already written dissectors for but need an OK from
* legal before I can submit a patch.
*
*/
#define LINKTYPE_AOS 222

/*
* WirelessHART (Highway Addressable Remote Transducer)
* From the HART Communication Foundation
* IEC/PAS 62591
*
* Requested by Sam Roberts <[email protected]>.
*/
#define LINKTYPE_WIHART 223

/*
* Fibre Channel FC-2 frames, beginning with a Frame_Header.
* Requested by Kahou Lei <[email protected]>.
*/
#define LINKTYPE_FC_2 224

/*
* Fibre Channel FC-2 frames, beginning with an encoding of the
* SOF, and ending with an encoding of the EOF.
*
* The encodings represent the frame delimiters as 4-byte sequences
* representing the corresponding ordered sets, with K28.5
* represented as 0xBC, and the D symbols as the corresponding
* byte values; for example, SOFi2, which is K28.5 - D21.5 - D1.2 - D21.2,
* is represented as 0xBC 0xB5 0x55 0x55.
*
* Requested by Kahou Lei <[email protected]>.
*/
#define LINKTYPE_FC_2_WITH_FRAME_DELIMS 225

/*
* Solaris ipnet pseudo-header; requested by Darren Reed <[email protected]>.
*
* The pseudo-header starts with a one-byte version number; for version 2,
* the pseudo-header is:
*
* struct dl_ipnetinfo {
* uint8_t dli_version;
* uint8_t dli_family;
* uint16_t dli_htype;
* uint32_t dli_pktlen;
* uint32_t dli_ifindex;
* uint32_t dli_grifindex;
* uint32_t dli_zsrc;
* uint32_t dli_zdst;
* };
*
* dli_version is 2 for the current version of the pseudo-header.
*
* dli_family is a Solaris address family value, so it's 2 for IPv4
* and 26 for IPv6.
*
* dli_htype is a "hook type" - 0 for incoming packets, 1 for outgoing
* packets, and 2 for packets arriving from another zone on the same
* machine.
*
* dli_pktlen is the length of the packet data following the pseudo-header
* (so the captured length minus dli_pktlen is the length of the
* pseudo-header, assuming the entire pseudo-header was captured).
*
* dli_ifindex is the interface index of the interface on which the
* packet arrived.
*
* dli_grifindex is the group interface index number (for IPMP interfaces).
*
* dli_zsrc is the zone identifier for the source of the packet.
*
* dli_zdst is the zone identifier for the destination of the packet.
*
* A zone number of 0 is the global zone; a zone number of 0xffffffff
* means that the packet arrived from another host on the network, not
* from another zone on the same machine.
*
* An IPv4 or IPv6 datagram follows the pseudo-header; dli_family indicates
* which of those it is.
*/
#define LINKTYPE_IPNET 226

/*
* CAN (Controller Area Network) frames, with a pseudo-header as supplied
* by Linux SocketCAN, and with multi-byte numerical fields in that header
* in big-endian byte order.
*
* See Documentation/networking/can.txt in the Linux source.
*
* Requested by Felix Obenhuber <[email protected]>.
*/
#define LINKTYPE_CAN_SOCKETCAN 227

/*
* Raw IPv4/IPv6; different from DLT_RAW in that the DLT_ value specifies
* whether it's v4 or v6. Requested by Darren Reed <[email protected]>.
*/
#define LINKTYPE_IPV4 228
#define LINKTYPE_IPV6 229

/*
* IEEE 802.15.4, exactly as it appears in the spec (no padding, no
* nothing), and with no FCS at the end of the frame; requested by
* Jon Smirl <[email protected]>.
*/
#define LINKTYPE_IEEE802_15_4_NOFCS 230

/*
* Raw D-Bus:
*
* https://www.freedesktop.org/wiki/Software/dbus
*
* messages:
*
* https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-messages
*
* starting with the endianness flag, followed by the message type, etc.,
* but without the authentication handshake before the message sequence:
*
* https://dbus.freedesktop.org/doc/dbus-specification.html#auth-protocol
*
* Requested by Martin Vidner <[email protected]>.
*/
#define LINKTYPE_DBUS 231

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>.
*/
#define LINKTYPE_JUNIPER_VS 232
#define LINKTYPE_JUNIPER_SRX_E2E 233
#define LINKTYPE_JUNIPER_FIBRECHANNEL 234

/*
* DVB-CI (DVB Common Interface for communication between a PC Card
* module and a DVB receiver). See
*
* https://www.kaiser.cx/pcap-dvbci.html
*
* for the specification.
*
* Requested by Martin Kaiser <[email protected]>.
*/
#define LINKTYPE_DVB_CI 235

/*
* Variant of 3GPP TS 27.010 multiplexing protocol. Requested
* by Hans-Christoph Schemmel <[email protected]>.
*/
#define LINKTYPE_MUX27010 236

/*
* STANAG 5066 D_PDUs. Requested by M. Baris Demiray
* <[email protected]>.
*/
#define LINKTYPE_STANAG_5066_D_PDU 237

/*
* Juniper-private data link type, as per request from
* Hannes Gredler <[email protected]>.
*/
#define LINKTYPE_JUNIPER_ATM_CEMIC 238

/*
* NetFilter LOG messages
* (payload of netlink NFNL_SUBSYS_ULOG/NFULNL_MSG_PACKET packets)
*
* Requested by Jakub Zawadzki <[email protected]>
*/
#define LINKTYPE_NFLOG 239

/*
* Hilscher Gesellschaft fuer Systemautomation mbH link-layer type
* for Ethernet packets with a 4-byte pseudo-header and always
* with the payload including the FCS, as supplied by their
* netANALYZER hardware and software.
*
* Requested by Holger P. Frommer <[email protected]>
*/
#define LINKTYPE_NETANALYZER 240

/*
* Hilscher Gesellschaft fuer Systemautomation mbH link-layer type
* for Ethernet packets with a 4-byte pseudo-header and FCS and
* 1 byte of SFD, as supplied by their netANALYZER hardware and
* software.
*
* Requested by Holger P. Frommer <[email protected]>
*/
#define LINKTYPE_NETANALYZER_TRANSPARENT 241

/*
* IP-over-InfiniBand, as specified by RFC 4391.
*
* Requested by Petr Sumbera <[email protected]>.
*/
#define LINKTYPE_IPOIB 242

/*
* MPEG-2 transport stream (ISO 13818-1/ITU-T H.222.0).
*
* Requested by Guy Martin <[email protected]>.
*/
#define LINKTYPE_MPEG_2_TS 243

/*
* ng4T GmbH's UMTS Iub/Iur-over-ATM and Iub/Iur-over-IP format as
* used by their ng40 protocol tester.
*
* Requested by Jens Grimmer <[email protected]>.
*/
#define LINKTYPE_NG40 244

/*
* Pseudo-header giving adapter number and flags, followed by an NFC
* (Near-Field Communications) Logical Link Control Protocol (LLCP) PDU,
* as specified by NFC Forum Logical Link Control Protocol Technical
* Specification LLCP 1.1.
*
* Requested by Mike Wakerly <[email protected]>.
*/
#define LINKTYPE_NFC_LLCP 245

/*
* pfsync output; DLT_PFSYNC is 18, which collides with DLT_CIP in
* SuSE 6.3, on OpenBSD, NetBSD, DragonFly BSD, and macOS, and
* is 121, which collides with DLT_HHDLC, in FreeBSD. We pick a
* shiny new link-layer header type value that doesn't collide with
* anything, in the hopes that future pfsync savefiles, if any,
* won't require special hacks to distinguish from other savefiles.
*/
#define LINKTYPE_PFSYNC 246

/*
* Raw InfiniBand packets, starting with the Local Routing Header.
*
* Requested by Oren Kladnitsky <[email protected]>.
*/
#define LINKTYPE_INFINIBAND 247

/*
* SCTP, with no lower-level protocols (i.e., no IPv4 or IPv6).
*
* Requested by Michael Tuexen <[email protected]>.
*/
#define LINKTYPE_SCTP 248

/*
* USB packets, beginning with a USBPcap header.
*
* Requested by Tomasz Mon <[email protected]>
*/
#define LINKTYPE_USBPCAP 249

/*
* Schweitzer Engineering Laboratories "RTAC" product serial-line
* packets.
*
* Requested by Chris Bontje <[email protected]>.
*/
#define LINKTYPE_RTAC_SERIAL 250

/*
* Bluetooth Low Energy air interface link-layer packets.
*
* Requested by Mike Kershaw <[email protected]>.
*/
#define LINKTYPE_BLUETOOTH_LE_LL 251

/*
* Link-layer header type for upper-protocol layer PDU saves from wireshark.
*
* the actual contents are determined by two TAGs, one or more of
* which is stored with each packet:
*
* EXP_PDU_TAG_DISSECTOR_NAME the name of the Wireshark dissector
* that can make sense of the data stored.
*
* EXP_PDU_TAG_HEUR_DISSECTOR_NAME the name of the Wireshark heuristic
* dissector that can make sense of the
* data stored.
*/
#define LINKTYPE_WIRESHARK_UPPER_PDU 252

/*
* Link-layer header type for the netlink protocol (nlmon devices).
*/
#define LINKTYPE_NETLINK 253

/*
* Bluetooth Linux Monitor headers for the BlueZ stack.
*/
#define LINKTYPE_BLUETOOTH_LINUX_MONITOR 254

/*
* Bluetooth Basic Rate/Enhanced Data Rate baseband packets, as
* captured by Ubertooth.
*/
#define LINKTYPE_BLUETOOTH_BREDR_BB 255

/*
* Bluetooth Low Energy link layer packets, as captured by Ubertooth.
*/
#define LINKTYPE_BLUETOOTH_LE_LL_WITH_PHDR 256

/*
* PROFIBUS data link layer.
*/
#define LINKTYPE_PROFIBUS_DL 257

/*
* Apple's DLT_PKTAP headers.
*
* Sadly, the folks at Apple either had no clue that the DLT_USERn values
* are for internal use within an organization and partners only, and
* didn't know that the right way to get a link-layer header type is to
* ask tcpdump.org for one, or knew and didn't care, so they just
* used DLT_USER2, which causes problems for everything except for
* their version of tcpdump.
*
* So I'll just give them one; hopefully this will show up in a
* libpcap release in time for them to get this into 10.10 Big Sur
* or whatever Mavericks' successor is called. LINKTYPE_PKTAP
* will be 258 *even on macOS*; that is *intentional*, so that
* PKTAP files look the same on *all* OSes (different OSes can have
* different numerical values for a given DLT_, but *MUST NOT* have
* different values for what goes in a file, as files can be moved
* between OSes!).
*/
#define LINKTYPE_PKTAP 258

/*
* Ethernet packets preceded by a header giving the last 6 octets
* of the preamble specified by 802.3-2012 Clause 65, section
* 65.1.3.2 "Transmit".
*/
#define LINKTYPE_EPON 259

/*
* IPMI trace packets, as specified by Table 3-20 "Trace Data Block Format"
* in the PICMG HPM.2 specification.
*/
#define LINKTYPE_IPMI_HPM_2 260

/*
* per Joshua Wright <[email protected]>, formats for Zwave captures.
*/
#define LINKTYPE_ZWAVE_R1_R2 261
#define LINKTYPE_ZWAVE_R3 262

/*
* per Steve Karg <[email protected]>, formats for Wattstopper
* Digital Lighting Management room bus serial protocol captures.
*/
#define LINKTYPE_WATTSTOPPER_DLM 263

/*
* ISO 14443 contactless smart card messages.
*/
#define LINKTYPE_ISO_14443 264

/*
* Radio data system (RDS) groups. IEC 62106.
* Per Jonathan Brucker <[email protected]>.
*/
#define LINKTYPE_RDS 265

/*
* USB packets, beginning with a Darwin (macOS, etc.) header.
*/
#define LINKTYPE_USB_DARWIN 266

/*
* OpenBSD DLT_OPENFLOW.
*/
#define LINKTYPE_OPENFLOW 267

/*
* SDLC frames containing SNA PDUs.
*/
#define LINKTYPE_SDLC 268

/*
* per "Selvig, Bjorn" <[email protected]> used for
* TI protocol sniffer.
*/
#define LINKTYPE_TI_LLN_SNIFFER 269

/*
* per: Erik de Jong <erikdejong at gmail.com> for
* https://github.com/eriknl/LoRaTap/releases/tag/v0.1
*/
#define LINKTYPE_LORATAP 270

/*
* per: Stefanha at gmail.com for
* https://lists.sandelman.ca/pipermail/tcpdump-workers/2017-May/000772.html
* and: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/vsockmon.h
* for: https://qemu-project.org/Features/VirtioVsock
*/
#define LINKTYPE_VSOCK 271

/*
* Nordic Semiconductor Bluetooth LE sniffer.
*/
#define LINKTYPE_NORDIC_BLE 272

/*
* Excentis DOCSIS 3.1 RF sniffer (XRA-31)
* per: bruno.verstuyft at excentis.com
* https://www.xra31.com/xra-header
*/
#define LINKTYPE_DOCSIS31_XRA31 273

/*
* mPackets, as specified by IEEE 802.3br Figure 99-4, starting
* with the preamble and always ending with a CRC field.
*/
#define LINKTYPE_ETHERNET_MPACKET 274

/*
* DisplayPort AUX channel monitoring data as specified by VESA
* DisplayPort(DP) Standard preceded by a pseudo-header.
* per dirk.eibach at gdsys.cc
*/
#define LINKTYPE_DISPLAYPORT_AUX 275

/*
* Linux cooked sockets v2.
*/
#define LINKTYPE_LINUX_SLL2 276

/*
* Sercos Monitor, per Manuel Jacob <manuel.jacob at steinbeis-stg.de>
*/
#define LINKTYPE_SERCOS_MONITOR 277

/*
* OpenVizsla http://openvizsla.org is open source USB analyzer hardware.
* It consists of FPGA with attached USB phy and FTDI chip for streaming
* the data to the host PC.
*
* Current OpenVizsla data encapsulation format is described here:
* https://github.com/matwey/libopenvizsla/wiki/OpenVizsla-protocol-description
*
*/
#define LINKTYPE_OPENVIZSLA 278

/*
* The Elektrobit High Speed Capture and Replay (EBHSCR) protocol is produced
* by a PCIe Card for interfacing high speed automotive interfaces.
*
* The specification for this frame format can be found at:
* https://www.elektrobit.com/ebhscr
*
* for Guenter.Ebermann at elektrobit.com
*
*/
#define LINKTYPE_EBHSCR 279

/*
* The https://fd.io vpp graph dispatch tracer produces pcap trace files
* in the format documented here:
* https://fdio-vpp.readthedocs.io/en/latest/gettingstarted/developers/vnet.html#graph-dispatcher-pcap-tracing
*/
#define LINKTYPE_VPP_DISPATCH 280

/*
* Broadcom Ethernet switches (ROBO switch) 4 bytes proprietary tagging format.
*/
#define LINKTYPE_DSA_TAG_BRCM 281
#define LINKTYPE_DSA_TAG_BRCM_PREPEND 282

/*
* IEEE 802.15.4 with pseudo-header and optional meta-data TLVs, PHY payload
* exactly as it appears in the spec (no padding, no nothing), and FCS if
* specified by FCS Type TLV; requested by James Ko <[email protected]>.
* Specification at https://github.com/jkcko/ieee802.15.4-tap
*/
#define LINKTYPE_IEEE802_15_4_TAP 283

/*
* Marvell (Ethertype) Distributed Switch Architecture proprietary tagging format.
*/
#define LINKTYPE_DSA_TAG_DSA 284
#define LINKTYPE_DSA_TAG_EDSA 285

/*
* Payload of lawful intercept packets using the ELEE protocol;
* https://socket.hr/draft-dfranusic-opsawg-elee-00.xml
* https://xml2rfc.tools.ietf.org/cgi-bin/xml2rfc.cgi?url=https://socket.hr/draft-dfranusic-opsawg-elee-00.xml&modeAsFormat=html/ascii
*/
#define LINKTYPE_ELEE 286

/*
* Serial frames transmitted between a host and a Z-Wave chip.
*/
#define LINKTYPE_Z_WAVE_SERIAL 287

/*
* USB 2.0, 1.1, and 1.0 packets as transmitted over the cable.
*/
#define LINKTYPE_USB_2_0 288

/*
* ATSC Link-Layer Protocol (A/330) packets.
*/
#define LINKTYPE_ATSC_ALP 289

#define LINKTYPE_HIGH_MATCHING_MAX 289 /* highest value in the "matching" range */

/*
* The DLT_ and LINKTYPE_ values in the "matching" range should be the
* same, so DLT_HIGH_MATCHING_MAX and LINKTYPE_HIGH_MATCHING_MAX should be the
* same.
*/
#if LINKTYPE_HIGH_MATCHING_MAX != DLT_HIGH_MATCHING_MAX
#error The LINKTYPE_ high matching range does not match the DLT_ matching range
#endif

/*
* Map a DLT_* code to the corresponding LINKTYPE_* code.
* Used to generate link-layer types written to savefiles.
*/
int
dlt_to_linktype(int dlt)
{
/*
* All values in the low matching range were handed out before
* assigning DLT_* codes became a free-for-all, so they're the
* same on all platforms, and thus are given LINKTYPE_* codes
* with the same numerical values as the corresponding DLT_*
* code.
*/
if (dlt >= DLT_LOW_MATCHING_MIN && dlt <= DLT_LOW_MATCHING_MAX)
return (dlt);

#if DLT_PFSYNC != LINKTYPE_PFSYNC
/*
* DLT_PFSYNC has a code on several platforms that's in the
* non-matching range, a code on FreeBSD that's in the high
* matching range and that's *not* equal to LINKTYPE_PFSYNC,
* and has a code on the rmaining platforms that's equal
* to LINKTYPE_PFSYNC, which is in the high matching range.
*
* Map it to LINKTYPE_PFSYNC if it's not equal to LINKTYPE_PFSYNC.
*/
if (dlt == DLT_PFSYNC)
return (LINKTYPE_PFSYNC);
#endif

/*
* DLT_PKTAP is defined as DLT_USER2 - which is in the high
* matching range - on Darwin because Apple used DLT_USER2
* on systems that users ran, not just as an internal thing.
*
* We map it to LINKTYPE_PKTAP if it's not equal to LINKTYPE_PKTAP
* so that DLT_PKTAP captures from Apple machines can be read by
* software that either doesn't handle DLT_USER2 or that handles it
* as something other than Apple PKTAP.
*/
#if DLT_PKTAP != LINKTYPE_PKTAP
if (dlt == DLT_PKTAP)
return (LINKTYPE_PKTAP);
#endif

/*
* For all other DLT_* codes in the high matching range, the DLT
* code value is the same as the LINKTYPE_* code value.
*/
if (dlt >= DLT_HIGH_MATCHING_MIN && dlt <= DLT_HIGH_MATCHING_MAX)
return (dlt);

/*
* These DLT_* codes have different values on different
* platforms, so we assigned them LINKTYPE_* codes just
* below the lower bound of the high matchig range;
* those values should never be equal to any DLT_*
* code, so that should avoid collisions.
*
* That way, for example, "raw IP" packets will have
* LINKTYPE_RAW as the code in all savefiles for
* which the code that writes them maps to that
* value, regardless of the platform on which they
* were written, so they should be readable on all
* platforms without having to determine on which
* platform they were written.
*
* We map the DLT_* codes on this platform, whatever
* it might be, to the corresponding LINKTYPE_* codes.
*/
if (dlt == DLT_ATM_RFC1483)
return (LINKTYPE_ATM_RFC1483);
if (dlt == DLT_RAW)
return (LINKTYPE_RAW);
if (dlt == DLT_SLIP_BSDOS)
return (LINKTYPE_SLIP_BSDOS);
if (dlt == DLT_PPP_BSDOS)
return (LINKTYPE_PPP_BSDOS);

/*
* These DLT_* codes were originally defined on some platform,
* and weren't defined on other platforms.
*
* At least some of them have values, on at least one platform,
* that collide with other DLT_* codes on other platforms, e.g.
* DLT_LOOP, so we don't just define them, on all platforms,
* as having the same value as on the original platform.
*
* Therefore, we assigned new LINKTYPE_* codes to them, and,
* on the platforms where they weren't originally defined,
* define the DLT_* codes to have the same value as the
* corresponding LINKTYPE_* codes.
*
* This means that, for capture files with the original
* platform's DLT_* code rather than the LINKTYPE_* code
* as a link-layer type, we will recognize those types
* on that platform, but not on other platforms.
*/
#ifdef DLT_FR
/* BSD/OS Frame Relay */
if (dlt == DLT_FR)
return (LINKTYPE_FRELAY);
#endif
#if DLT_HDLC != LINKTYPE_NETBSD_HDLC
/* NetBSD HDLC */
if (dlt == DLT_HDLC)
return (LINKTYPE_NETBSD_HDLC);
#endif
#if DLT_C_HDLC != LINKTYPE_C_HDLC
/* BSD/OS Cisco HDLC */
if (dlt == DLT_C_HDLC)
return (LINKTYPE_C_HDLC);
#endif
#if DLT_LOOP != LINKTYPE_LOOP
/* OpenBSD DLT_LOOP */
if (dlt == DLT_LOOP)
return (LINKTYPE_LOOP);
#endif
#if DLT_ENC != LINKTYPE_ENC
/* OpenBSD DLT_ENC */
if (dlt == DLT_ENC)
return (LINKTYPE_ENC);
#endif

/*
* These DLT_* codes are not on all platforms, but, so far,
* there don't appear to be any platforms that define
* other codes with those values; we map them to
* different LINKTYPE_* codes anyway, just in case.
*/
/* Linux ATM Classical IP */
if (dlt == DLT_ATM_CLIP)
return (LINKTYPE_ATM_CLIP);

/*
* A few other values, defined on some platforms, not in
* either matching range, but not colliding with anything
* else, so they're given the same LINKTYPE_* code as
* their DLT_* code.
*/
if (dlt == DLT_REDBACK_SMARTEDGE || dlt == DLT_PPP_SERIAL ||
dlt == DLT_PPP_ETHER || dlt == DLT_SYMANTEC_FIREWALL)
return (dlt);

/*
* If we don't have a mapping for this DLT_* code, return an
* error; that means that this is a DLT_* value with no
* corresponding LINKTYPE_ value, and we need to assign one.
*/
return (-1);
}

/*
* Map a LINKTYPE_* code to the corresponding DLT_* code.
* Used to translate link-layer types in savefiles to the
* DLT_* codes to provide to callers of libpcap.
*/
int
linktype_to_dlt(int linktype)
{
/*
* All values in the low matching range were handed out before
* assigning DLT_* codes became a free-for-all, so they're the
* same on all platforms, and are thus used as the LINKTYPE_*
* codes in capture files.
*/
if (linktype >= LINKTYPE_LOW_MATCHING_MIN &&
linktype <= LINKTYPE_LOW_MATCHING_MAX)
return (linktype);

#if LINKTYPE_PFSYNC != DLT_PFSYNC
/*
* DLT_PFSYNC has a code on several platforms that's in the
* non-matching range, a code on FreeBSD that's in the high
* matching range and that's *not* equal to LINKTYPE_PFSYNC,
* and has a code on the rmaining platforms that's equal
* to LINKTYPE_PFSYNC, which is in the high matching range.
*
* Map LINKTYPE_PFSYNC to whatever DLT_PFSYNC is on this
* platform, if the two aren't equal.
*/
if (linktype == LINKTYPE_PFSYNC)
return (DLT_PFSYNC);
#endif

/*
* DLT_PKTAP is defined as DLT_USER2 - which is in the high
* matching range - on Darwin because Apple used DLT_USER2
* on systems that users ran, not just as an internal thing.
*
* We map LINKTYPE_PKTAP to the platform's DLT_PKTAP for
* the benefit of software that's expecting DLT_PKTAP
* (even if that's DLT_USER2) for an Apple PKTAP capture.
*
* (Yes, this is an annoyance if you want to read a
* LINKTYPE_USER2 packet as something other than DLT_PKTAP
* on a Darwin-based OS, as, on that OS, DLT_PKTAP and DLT_USER2
* are the same. Feel free to complain to Apple about this.)
*/
#if LINKTYPE_PKTAP != DLT_PKTAP
if (linktype == LINKTYPE_PKTAP)
return (DLT_PKTAP);
#endif

/*
* These DLT_* codes have different values on different
* platforms, so we assigned them LINKTYPE_* codes just
* below the lower bound of the high matchig range;
* those values should never be equal to any DLT_*
* code, so that should avoid collisions.
*
* That way, for example, "raw IP" packets will have
* LINKTYPE_RAW as the code in all savefiles for
* which the code that writes them maps to that
* value, regardless of the platform on which they
* were written, so they should be readable on all
* platforms without having to determine on which
* platform they were written.
*
* We map the LINKTYPE_* codes to the corresponding
* DLT_* code on this platform.
*/
if (linktype == LINKTYPE_ATM_RFC1483)
return (DLT_ATM_RFC1483);
if (linktype == LINKTYPE_RAW)
return (DLT_RAW);
if (linktype == LINKTYPE_SLIP_BSDOS)
return (DLT_SLIP_BSDOS);
if (linktype == LINKTYPE_PPP_BSDOS)
return (DLT_PPP_BSDOS);

/*
* These DLT_* codes were originally defined on some platform,
* and weren't defined on other platforms.
*
* At least some of them have values, on at least one platform,
* that collide with other DLT_* codes on other platforms, e.g.
* DLT_LOOP, so we don't just define them, on all platforms,
* as having the same value as on the original platform.
*
* Therefore, we assigned new LINKTYPE_* codes to them, and,
* on the platforms where they weren't originally defined,
* define the DLT_* codes to have the same value as the
* corresponding LINKTYPE_* codes.
*
* This means that, for capture files with the original
* platform's DLT_* code rather than the LINKTYPE_* code
* as a link-layer type, we will recognize those types
* on that platform, but not on other platforms.
*
* We map the LINKTYPE_* codes to the corresponding
* DLT_* code on platforms where the two codes differ..
*/
#ifdef DLT_FR
/* BSD/OS Frame Relay */
if (linktype == LINKTYPE_FRELAY)
return (DLT_FR);
#endif
#if LINKTYPE_NETBSD_HDLC != DLT_HDLC
/* NetBSD HDLC */
if (linktype == LINKTYPE_NETBSD_HDLC)
return (DLT_HDLC);
#endif
#if LINKTYPE_C_HDLC != DLT_C_HDLC
/* BSD/OS Cisco HDLC */
if (linktype == LINKTYPE_C_HDLC)
return (DLT_C_HDLC);
#endif
#if LINKTYPE_LOOP != DLT_LOOP
/* OpenBSD DLT_LOOP */
if (linktype == LINKTYPE_LOOP)
return (DLT_LOOP);
#endif
#if LINKTYPE_ENC != DLT_ENC
/* OpenBSD DLT_ENC */
if (linktype == LINKTYPE_ENC)
return (DLT_ENC);
#endif

/*
* These DLT_* codes are not on all platforms, but, so far,
* there don't appear to be any platforms that define
* other codes with those values; we map them to
* different LINKTYPE_* values anyway, just in case.
*
* LINKTYPE_ATM_CLIP is a special case. DLT_ATM_CLIP is
* not on all platforms, but, so far, there don't appear
* to be any platforms that define it as anything other
* than 19; we define LINKTYPE_ATM_CLIP as something
* other than 19, just in case. That value is in the
* high matching range, so we have to check for it.
*/
/* Linux ATM Classical IP */
if (linktype == LINKTYPE_ATM_CLIP)
return (DLT_ATM_CLIP);

/*
* For all other values, return the linktype code as the
* DLT_* code.
*
* If the code is in the high matching range, the
* DLT_* code is the same as the LINKTYPE_* code.
*
* If the code is greater than the maximum value in
* the high matching range, it may be a value from
* a newer version of libpcap; we provide it in case
* the program' capable of handling it.
*
* If the code is less than the minimum value in the
* high matching range, it might be from a capture
* written by code that doesn't map non-matching range
* DLT_* codes to the appropriate LINKTYPE_* code, so
* we'll just pass it through, so that *if it was written
* on this platform* it will be interpreted correctly.
* (We don't know whether it was written on this platform,
* but at least this way there's *some* chance that it
* can be read.)
*/
return linktype;
}

/*
* Return the maximum snapshot length for a given DLT_ value.
*
* For most link-layer types, we use MAXIMUM_SNAPLEN.
*
* For DLT_DBUS, the maximum is 128MiB, as per
*
* https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-messages
*
* For DLT_EBHSCR, the maximum is 8MiB, as per
*
* https://www.elektrobit.com/ebhscr
*
* For DLT_USBPCAP, the maximum is 1MiB, as per
*
* https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=15985
*/
u_int
max_snaplen_for_dlt(int dlt)
{
switch (dlt) {

case DLT_DBUS:
return 128*1024*1024;

case DLT_EBHSCR:
return 8*1024*1024;

case DLT_USBPCAP:
return 1024*1024;

default:
return MAXIMUM_SNAPLEN;
}
}