stand_alone: true ipr: trust200902 docname: draft-gharris-opsawg-pcap-latest cat: info pi: symrefs: 'yes' toc: 'yes' compact: 'yes' subcompact: 'no' inline: 'yes' sortrefs: 'no' strict: 'yes' title: PCAP Capture File Format abbrev: pcap author:
- role: editor ins: G. Harris name: Guy Harris org: '' email: [email protected]
- ins: M. Richardson name: Michael C. Richardson org: Sandelman Software Works Inc abbrev: Sandelman email: [email protected] uri: http://www.sandelman.ca/ normative: informative: I-D.tuexen-opsawg-pcapng: RFC8126:
--- abstract
This document describes the format used by the libpcap library to record captured packets to a file. Programs using the libpcap library to read and write those files, and thus reading and writing files in that format, include tcpdump.
--- middle
In the late 1980's, Van Jacobson, Steve McCanne, and others at the Network Research Group at Lawrence Berkeley National Laboratory developed the tcpdump program to capture and dissect network traces. The code to capture traffic, using low-level mechanisms in various operating systems, and to read and write network traces to a file was later put into a library named libpcap.
This document describes the format used by tcpdump, and other programs using libpcap, to read and write network traces.
{::boilerplate bcp14}
A capture file begins with a File Header, followed by zero or more Packet Records, one per packet.
All fields in the File Header and in Packet Records will always be saved according to the characteristics (little endian / big endian) of the capturing machine. This refers to all the fields that are saved as numbers and that span over two or more octets.
The approach of having the file saved in the native format of the generating host is more efficient because it avoids translation of data when reading / writing on the host itself, which is the most common case when generating/processing capture captures.
The packets are shown in traditional IETF diagram, with the bits numbered from the left to the right. The bit numbering does not reflect the binary value position, as IETF protocols are traditionally in big-endian network-byte order. The most significant bit is therefore on the left in this diagram as if the file is being stored on a big-endian system.
The File Header has the following format:
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 | Magic Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4 | Major Version | Minor Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8 | Reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 | Reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16 | SnapLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
20 | FCS |f|0 0 0 0 0 0 0 0 0 0 0 0| LinkType |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
{: #fig-header title='File Header' align="left"}
The File Header length is 24 octets.
The meaning of the fields in the File Header is:
Magic Number (32 bits): : an unsigned magic number, whose value is either the hexadecimal number 0xA1B2C3D4 or the hexadecimal number 0xA1B23C4D. : If the value is 0xA1B2C3D4, time stamps in Packet Records (see Figure 2) are in seconds and microseconds; if it is 0xA1B23C4D, time stamps in Packet Records are in seconds and nanoseconds. : These numbers can be used to distinguish sessions that have been saved on little-endian machines from the ones saved on big-endian machines, and to heuristically identify pcap files.
Major Version (16 bits): : an unsigned value, giving the number of the current major version of the format. The value for the current version of the format is 2. This value should change if the format changes in such a way that code that reads the new format could not read the old format (i.e., code to read both formats would have to check the version number and use different code paths for the two formats) and code that reads the old format could not read the new format.
Minor Version (16 bits): : an unsigned value, giving the number of the current minor version of the format. The value is for the current version of the format is 4. This value should change if the format changes in such a way that code that reads the new format could read the old format without checking the version number but code that reads the old format could not read all files in the new format.
Reserved1 (32 bits): : not used - SHOULD be filled with 0 by pcap file writers, and MUST be ignored by pcap file readers. This value was documented by some older implementations as "gmt to local correction". Some older pcap file writers stored non-zero values in this field.
Reserved2 (32 bits): : not used - SHOULD be filled with 0 by pcap file writers, and MUST be ignored by pcap file readers. This value was documented by some older implementations as "accuracy of timestamps". Some older pcap file writers stored non-zero values in this field.
SnapLen (32 bits): : an unsigned value indicating the maximum number of octets captured from each packet. The portion of each packet that exceeds this value will not be stored in the file. This value MUST NOT be zero; if no limit was specified, the value should be a number greater than or equal to the largest packet length in the file.
LinkType (16 bits): : a 16-bit unsigned value that defines the link layer type of packets in the file. This field is defined in the {{linktype}} IANA registry.
Frame Cyclic Sequence (FCS) present (4 bits): : if the "f" bit is set, then the 3 FCS bits provide the number of 16-bit (2 byte) words of FCS that are appended to each packet. : valid values are between 0 and 7, with ethernet typically having a length of 4 bytes, or a value of 2.
The bits marked as zero MUST be set to zero by pcap writers, and MUST be ignored by pcap readers.
A Packet Record is the standard container for storing the packets coming from the network.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 | Timestamp (Seconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4 | Timestamp (Microseconds or nanoseconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8 | Captured Packet Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12 | Original Packet Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16 / /
/ Packet Data /
/ variable length /
/ /
+---------------------------------------------------------------+
{: #fig-record title='Packet Record' align="left"}
The Packet Header length is 16 octets.
The meaning of the fields in the Packet Record is:
Timestamp (Seconds) and Timestamp (Microseconds or nanoseconds): : seconds and fraction of a seconds values of a timestamp. : The seconds value is a 32-bit unsigned integer that represents the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC, and the microseconds or nanoseconds value represents the number of microseconds or nanoseconds that have elapsed since that seconds. : Whether the value represents microseconds or nanoseconds is specified by the magic number in the File Header.
Captured Packet Length (32 bits): : an unsigned value that indicates the number of octets captured from the packet (i.e. the length of the Packet Data field). It will be the minimum value among the Original Packet Length and the snapshot length for the interface (SnapLen, defined in Figure 1).
Original Packet Length (32 bits): : an unsigned value that indicates the actual length of the packet when it was transmitted on the network. It can be different from the Captured Packet Length if the packet has been truncated by the capture process.
Packet Data: : the data coming from the network, including link-layer headers. The actual length of this field is Captured Packet Length. The format of the link-layer headers depends on the LinkType field specified in the file header (see Figure 1) and it is specified in the entry for that format in [LINKTYPES].
The recommended file name extension for the "PCAP Capture File Format" specified in this document is ".pcap".
On Windows and macOS, files are distinguished by an extension to their filename. Such an extension is technically not actually required, as applications should be able to automatically detect the pcap file format through the "magic bytes" at the beginning of the file, as some other UN*X desktop environments do. However, using name extensions makes it easier to work with files (e.g. visually distinguish file formats) so it is recommended - though not required - to use .pcap as the name extension for files following this specification.
Please note: To avoid confusion (such as the current usage of .cap for a plethora of different capture file formats) file name extensions other than .pcap should be avoided.
There is new work to create the PCAP Next Generation capture File Format (see {{I-D.tuexen-opsawg-pcapng}}). The new file format is not compatible with this specification, but many programs read both transparently. Files of that type will usually start with a Section Header Block, with a magic number of 0x0A0D0D0A.
TBD.
This document requires the following IANA actions:
This section registers the the 'application/pcap' in the "Media Types" registry. These media types are used to indicate that the content is packet capture as described in this document.
Type name: application
Subtype name: pcap
Required parameters: none
Optional parameters: none
Encoding considerations: PCAP files contain network packets
Security considerations: See Security Considerations, Section
Interoperability considerations: The format is designed to be broadly interoperable.
Published specification: THIS RFC.
Applications that use this media type: tcpdump, wireshark, others.
Additional information:
Magic number(s): 0xA1B2C3D4, and 0xA1B23C4D in both endian orders
File extension(s): .pcap
Macintosh file type code(s): none
Person & email address to contact for further information: The Tcpdump Group, www.tcpdump.org
Intended usage: LIMITED
Restrictions on usage: NONE
Author: Guy Harris and Michael Richardson
Change controller: The Tcpdump Group
Provisional registration? (standards tree only): NO
IANA is requested to create a new Registry entitled: "The PCAP Registry", and within that Registry to create a table called: "PCAP LinkType List".
The LinkType Registry is a table of 16-bit numbers. The Registry has three sections according to {{RFC8126}}:
-
values from 0 to 32767 are marked as Specification Required.
-
except that values 147 to 162 are reserved for Private Use
-
values from 32768 to 65000 are marked as First-Come First-Served.
-
values from 65000 to 65535 are marked as Private Use.
The Registry has four columns: the symbolic name (LINKTYPE_something), the integer value, a very short description, and the document/requestor reference.
The Registry shall be populated as follows in the table below. In each case here, the reference should be http://www.tcpdump.org/linktypes.html, which is not repeated.
The initial value of table is base upon the Link type list maintained by libpcap, and published on the tcpdump.org web site as http://www.tcpdump.org/linktypes.html.
There is often an associated DLT value which are often identical in value, but not universally so. DLT values are associated with specific operation system captures, and are operating system specific.
| LINKTYPE name | LINKTYPE value | description |
|---|---|---|
| LINKTYPE_NULL | 0 | BSD loopback encapsulation |
| LINKTYPE_ETHERNET | 1 | IEEE 802.3 Ethernet |
| LINKTYPE_AX25 | 3 | AX.25 packet |
| LINKTYPE_IEEE802_5 | 6 | IEEE 802.5 Token Ring |
| LINKTYPE_ARCNET_BSD | 7 | ARCNET Data Packets |
| LINKTYPE_SLIP | 8 | SLIP, w/LINKTYPE_SLIP header. |
| LINKTYPE_PPP | 9 | PPP, as per RFC 1661/RFC 1662 |
| LINKTYPE_FDDI | 10 | FDDI: per ANSI INCITS 239-1994. |
| LINKTYPE_PPP_HDLC | 50 | PPP in HDLC-like framing, as per RFC 1662 |
| LINKTYPE_PPP_ETHER | 51 | PPPoE; per RFC 2516 |
| LINKTYPE_ATM_RFC1483 | 100 | RFC 1483 LLC/SNAP-encapsulated ATM |
| LINKTYPE_RAW | 101 | Raw IP; begins with an IPv4 or IPv6 header |
| LINKTYPE_C_HDLC | 104 | Cisco PPP with HDLC framing, as per section 4.3.1 of RFC 1547 |
| LINKTYPE_IEEE802_11 | 105 | IEEE 802.11 wireless LAN. |
| LINKTYPE_FRELAY | 107 | Frame Relay LAPF frames |
| LINKTYPE_LOOP | 108 | OpenBSD loopback encapsulation |
| LINKTYPE_LINUX_SLL | 113 | Linux "cooked" capture encapsulation |
| LINKTYPE_LTALK | 114 | Apple LocalTalk |
| LINKTYPE_PFLOG | 117 | OpenBSD pflog; "struct pfloghdr" structure |
| LINKTYPE_IEEE802_11_PRISM | 119 | Prism monitor mode |
| LINKTYPE_IP_OVER_FC | 122 | RFC 2625 IP-over-Fibre Channel |
| LINKTYPE_SUNATM | 123 | ATM traffic, / per SunATM devices |
| LINKTYPE_IEEE802_11_RADIOTAP | 127 | Radiotap - followed by an 802.11 header |
| LINKTYPE_ARCNET_LINUX | 129 | ARCNET Data Packets, per RFC 1051 frames w/variations |
| LINKTYPE_APPLE_IP_OVER_IEEE1394 | 138 | Apple IP-over-IEEE 1394 cooked header |
| LINKTYPE_MTP2_WITH_PHDR | 139 | Signaling System 7 (SS7) Message Transfer Part Level ITU-T Q.703 |
| LINKTYPE_MTP2 | 140 | SS7 Level 2, Q.703 |
| LINKTYPE_MTP3 | 141 | SS7 Level 3, Q.704 |
| LINKTYPE_SCCP | 142 | SS7 Control Part, ITU-T Q.711/Q.712/Q.713/Q.714 |
| LINKTYPE_DOCSIS | 143 | DOCSIS MAC frames, DOCSIS 3.1 |
| LINKTYPE_LINUX_IRDA | 144 | Linux-IrDA packets w/LINKTYPE_LINUX_IRDA header |
| LINKTYPE_IEEE802_11_AVS | 163 | AVS monitor mode w/802.11 header |
| LINKTYPE_BACNET_MS_TP | 165 | BACnet MS/TP frames, per 9.3 MS/TP Frame Format ANSI 135 |
| LINKTYPE_PPP_PPPD | 166 | PPP in HDLC-like encapsulation, like LINKTYPE_PPP_HDLC, different stuffing |
| LINKTYPE_GPRS_LLC | 169 | General Packet Radio Service Logical Link Control, as per 3GPP TS 04.64 |
| LINKTYPE_GPF_T | 170 | Transparent-mapped generic framing procedure, as specified by ITU-T Recommendation G.7041/Y.1303 |
| LINKTYPE_GPF_F | 171 | Frame-mapped generic framing procedure, as specified by ITU-T Recommendation G.7041/Y.1303 |
| LINKTYPE_LINUX_LAPD | 177 | Link Access Procedures on the D Channel (LAPD) frames, as specified by ITU-T Recommendation Q.920 and ITU-T Recommendation Q.921 , captured via vISDN, with a LINKTYPE_LINUX_LAPD header , followed by the Q.921 frame, starting with the address field. |
| LINKTYPE_MFR | 182 | FRF.16.1 Multi-Link Frame Relay frames, beginning with an FRF.12 Interface fragmentation format fragmentation header. |
| LINKTYPE_BLUETOOTH_HCI_H4 | 187 | Bluetooth HCI UART transport layer; the frame contains an HCI packet indicator byte, as specified by the UART Transport Layer portion of the most recent Bluetooth Core specification , followed by an HCI packet of the specified packet type, as specified by the Host Controller Interface Functional Specification portion of the most recent Bluetooth Core Specification. |
| LINKTYPE_USB_LINUX | 189 | USB packets, beginning with a Linux USB header, as specified by the struct usbmon_packet in the Documentation/usb/usbmon.txt file in the Linux source tree. Only the first 48 bytes of that header are present. All fields in the header are in host byte order. When performing a live capture, the host byte order is the byte order of the machine on which the packets are captured. When reading a pcap file, the byte order is the byte order for the file, as specified by the file's magic number; when reading a pcapng file, the byte order is the byte order for the section of the pcapng file, as specified by the Section Header Block. |
| LINKTYPE_PPI | 192 | Per-Packet Information information, as specified by the Per-Packet Information Header Specification , followed by a packet with the LINKTYPE_ value specified by the pph_dlt field of that header. |
| LINKTYPE_IEEE802_15_4_WITHFCS | 195 | IEEE 802.15.4 Low-Rate Wireless Networks, with each packet having the FCS at the end of the frame. |
| LINKTYPE_SITA | 196 | Various link-layer types, with a pseudo-header , for SITA |
| LINKTYPE_ERF | 197 | Various link-layer types, with a pseudo-header, for Endace DAG cards; encapsulates Endace ERF records. |
| LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR | 201 | Bluetooth HCI UART transport layer; the frame contains a 4-byte direction field, in network byte order (big-endian), the low-order bit of which is set if the frame was sent from the host to the controller and clear if the frame was received by the host from the controller, followed by an HCI packet indicator byte, as specified by the UART Transport Layer portion of the most recent Bluetooth Core specification , followed by an HCI packet of the specified packet type, as specified by the Host Controller Interface Functional Specification portion of the most recent Bluetooth Core Specification. |
| LINKTYPE_AX25_KISS | 202 | AX.25 packet, with a 1-byte KISS header containing a type indicator. |
| LINKTYPE_LAPD | 203 | Link Access Procedures on the D Channel (LAPD) frames, as specified by ITU-T Recommendation Q.920 and ITU-T Recommendation Q.921 , starting with the address field, with no pseudo-header. |
| LINKTYPE_PPP_WITH_DIR | 204 | PPP, as per RFC 1661 and RFC 1662 , preceded with a one-byte pseudo-header with a zero value meaning received by this host and a non-zero value meaning sent by this host; if the first 2 bytes are 0xff and 0x03, it's PPP in HDLC-like framing, with the PPP header following those two bytes, otherwise it's PPP without framing, and the packet begins with the PPP header. The data in the frame is not octet-stuffed or bit-stuffed. |
| LINKTYPE_C_HDLC_WITH_DIR | 205 | Cisco PPP with HDLC framing, as per section 4.3.1 of RFC 1547 , preceded with a one-byte pseudo-header with a zero value meaning received by this host and a non-zero value meaning sent by this host. |
| LINKTYPE_FRELAY_WITH_DIR | 206 | Frame Relay LAPF frames, beginning with a one-byte pseudo-header with a zero value meaning received by this host (DCE->DTE) and a non-zero value meaning sent by this host (DTE->DCE), followed by an ITU-T Recommendation Q.922 LAPF header starting with the address field, and without an FCS at the end of the frame. |
| LINKTYPE_LAPB_WITH_DIR | 207 | Link Access Procedure, Balanced (LAPB), as specified by ITU-T Recommendation X.25 , preceded with a one-byte pseudo-header with a zero value meaning received by this host (DCE->DTE) and a non-zero value meaning sent by this host (DTE->DCE). |
| LINKTYPE_IPMB_LINUX | 209 | IPMB over an I2C circuit, with a Linux-specific pseudo-header |
| LINKTYPE_IEEE802_15_4_NONASK_PHY | 215 | IEEE 802.15.4 Low-Rate Wireless Networks, with each packet having the FCS at the end of the frame, and with the PHY-level data for the O-QPSK, BPSK, GFSK, MSK, and RCC DSS BPSK PHYs (4 octets of 0 as preamble, one octet of SFD, one octet of frame length + reserved bit) preceding the MAC-layer data (starting with the frame control field). |
| LINKTYPE_USB_LINUX_MMAPPED | 220 | USB packets, beginning with a Linux USB header, as specified by the struct usbmon_packet in the Documentation/usb/usbmon.txt file in the Linux source tree. All 64 bytes of the header are present. All fields in the header are in host byte order. When performing a live capture, the host byte order is the byte order of the machine on which the packets are captured. When reading a pcap file, the byte order is the byte order for the file, as specified by the file's magic number; when reading a pcapng file, the byte order is the byte order for the section of the pcapng file, as specified by the Section Header Block. For isochronous transfers, the ndesc field specifies the number of isochronous descriptors that follow. |
| LINKTYPE_FC_2 | 224 | Fibre Channel FC-2 frames, beginning with a Frame_Header. |
| LINKTYPE_FC_2_WITH_FRAME_DELIMS | 225 | Fibre Channel FC-2 frames, beginning an encoding of the SOF, followed by a Frame_Header, and ending with an encoding of the SOF. 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. |
| LINKTYPE_IPNET | 226 | Solaris ipnet pseudo-header , followed by an IPv4 or IPv6 datagram. |
| LINKTYPE_CAN_SOCKETCAN | 227 | CAN (Controller Area Network) frames, with a pseudo-header followed by the frame payload. |
| LINKTYPE_IPV4 | 228 | Raw IPv4; the packet begins with an IPv4 header. |
| LINKTYPE_IPV6 | 229 | Raw IPv6; the packet begins with an IPv6 header. |
| LINKTYPE_IEEE802_15_4_NOFCS | 230 | IEEE 802.15.4 Low-Rate Wireless Network, without the FCS at the end of the frame. |
| LINKTYPE_DBUS | 231 | Raw D-Bus messages , starting with the endianness flag, followed by the message type, etc., but without the authentication handshake before the message sequence. |
| LINKTYPE_DVB_CI | 235 | DVB-CI (DVB Common Interface for communication between a PC Card module and a DVB receiver), with the message format specified by the PCAP format for DVB-CI specification |
| LINKTYPE_MUX27010 | 236 | Variant of 3GPP TS 27.010 multiplexing protocol (similar to, but not the same as, 27.010). |
| LINKTYPE_STANAG_5066_D_PDU | 237 | D_PDUs as described by NATO standard STANAG 5066, starting with the synchronization sequence, and including both header and data CRCs. The current version of STANAG 5066 is backwards-compatible with the 1.0.2 version , although newer versions are classified. |
| LINKTYPE_NFLOG | 239 | Linux netlink NETLINK NFLOG socket log messages. |
| LINKTYPE_NETANALYZER | 240 | Pseudo-header for Hilscher Gesellschaft für Systemautomation mbH netANALYZER devices , followed by an Ethernet frame, beginning with the MAC header and ending with the FCS. |
| LINKTYPE_NETANALYZER_TRANSPARENT | 241 | Pseudo-header for Hilscher Gesellschaft für Systemautomation mbH netANALYZER devices , followed by an Ethernet frame, beginning with the preamble, SFD, and MAC header, and ending with the FCS. |
| LINKTYPE_IPOIB | 242 | IP-over-InfiniBand, as specified by RFC 4391 section 6 |
| LINKTYPE_MPEG_2_TS | 243 | MPEG-2 Transport Stream transport packets, as specified by ISO 13818-1/ ITU-T Recommendation H.222.0 (see table 2-2 of section 2.4.3.2 Transport Stream packet layer). |
| LINKTYPE_NG40 | 244 | Pseudo-header for ng4T GmbH's UMTS Iub/Iur-over-ATM and Iub/Iur-over-IP format as used by their ng40 protocol tester , followed by frames for the Frame Protocol as specified by 3GPP TS 25.427 for dedicated channels and 3GPP TS 25.435 for common/shared channels in the case of ATM AAL2 or UDP traffic, by SSCOP packets as specified by ITU-T Recommendation Q.2110 for ATM AAL5 traffic, and by NBAP packets for SCTP traffic. |
| LINKTYPE_NFC_LLCP | 245 | Pseudo-header for NFC LLCP packet captures , followed by frame data for the LLCP Protocol as specified by NFCForum-TS-LLCP_1.1 |
| LINKTYPE_INFINIBAND | 247 | Raw InfiniBand frames, starting with the Local Routing Header, as specified in Chapter 5 Data packet format of InfiniBand™ Architectural Specification Release 1.2.1 Volume 1 - General Specifications |
| LINKTYPE_SCTP | 248 | SCTP packets, as defined by RFC 4960 , with no lower-level protocols such as IPv4 or IPv6. |
| LINKTYPE_USBPCAP | 249 | USB packets, beginning with a USBPcap header |
| LINKTYPE_RTAC_SERIAL | 250 | Serial-line packet header for the Schweitzer Engineering Laboratories RTAC product , followed by a payload for one of a number of industrial control protocols. |
| LINKTYPE_BLUETOOTH_LE_LL | 251 | Bluetooth Low Energy air interface Link Layer packets, in the format described in section 2.1 PACKET FORMAT of volume 6 of the Bluetooth Specification Version 4.0 (see PDF page 2200), but without the Preamble. |
| LINKTYPE_NETLINK | 253 | Linux Netlink capture encapsulation |
| LINKTYPE_BLUETOOTH_LINUX_MONITOR | 254 | Bluetooth Linux Monitor encapsulation of traffic for the BlueZ stack |
| LINKTYPE_BLUETOOTH_BREDR_BB | 255 | Bluetooth Basic Rate and Enhanced Data Rate baseband packets |
| LINKTYPE_BLUETOOTH_LE_LL_WITH_PHDR | 256 | Bluetooth Low Energy link-layer packets |
| LINKTYPE_PROFIBUS_DL | 257 | PROFIBUS data link layer packets, as specified by IEC standard 61158-4-3, beginning with the start delimiter, ending with the end delimiter, and including all octets between them. |
| LINKTYPE_PKTAP | 258 | Apple PKTAP capture encapsulation |
| LINKTYPE_EPON | 259 | Ethernet-over-passive-optical-network packets, starting with the last 6 octets of the modified preamble as specified by 65.1.3.2 Transmit in Clause 65 of Section 5 of IEEE 802.3 , followed immediately by an Ethernet frame. |
| LINKTYPE_IPMI_HPM_2 | 260 | IPMI trace packets, as specified by Table 3-20 Trace Data Block Format in the PICMG HPM.2 specification The time stamps for packets in this format must match the time stamps in the Trace Data Blocks. |
| LINKTYPE_ZWAVE_R1_R2 | 261 | Z-Wave RF profile R1 and R2 packets , as specified by ITU-T Recommendation G.9959 , with some MAC layer fields moved. |
| LINKTYPE_ZWAVE_R3 | 262 | Z-Wave RF profile R3 packets , as specified by ITU-T Recommendation G.9959 , with some MAC layer fields moved. |
| LINKTYPE_WATTSTOPPER_DLM | 263 | Formats for WattStopper Digital Lighting Management (DLM) and Legrand Nitoo Open protocol common packet structure captures. |
| LINKTYPE_ISO_14443 | 264 | Messages between ISO 14443 contactless smartcards (Proximity Integrated Circuit Card, PICC) and card readers (Proximity Coupling Device, PCD), with the message format specified by the PCAP format for ISO14443 specification |
| LINKTYPE_RDS | 265 | Radio data system (RDS) groups, as per IEC 62106, encapsulated in this form |
| LINKTYPE_USB_DARWIN | 266 | USB packets, beginning with a Darwin (macOS, etc.) USB header |
| LINKTYPE_SDLC | 268 | SDLC packets, as specified by Chapter 1, DLC Links, section Synchronous Data Link Control (SDLC) of Systems Network Architecture Formats, GA27-3136-20 , without the flag fields, zero-bit insertion, or Frame Check Sequence field, containing SNA path information units (PIUs) as the payload. |
| LINKTYPE_LORATAP | 270 | LoRaTap pseudo-header , followed by the payload, which is typically the PHYPayload from the LoRaWan specification |
| LINKTYPE_VSOCK | 271 | Protocol for communication between host and guest machines in VMware and KVM hypervisors. |
| LINKTYPE_NORDIC_BLE | 272 | Messages to and from a Nordic Semiconductor nRF Sniffer for Bluetooth LE packets, beginning with a pseudo-header |
| LINKTYPE_DOCSIS31_XRA31 | 273 | DOCSIS packets and bursts, preceded by a pseudo-header giving metadata about the packet |
| LINKTYPE_ETHERNET_MPACKET | 274 | mPackets, as specified by IEEE 802.3br Figure 99-4, starting with the preamble and always ending with a CRC field. |
| LINKTYPE_DISPLAYPORT_AUX | 275 | DisplayPort AUX channel monitoring data as specified by VESA DisplayPort(DP) Standard preceded by a pseudo-header |
| LINKTYPE_LINUX_SLL2 | 276 | Linux cooked capture encapsulation v2 |
| LINKTYPE_OPENVIZSLA | 278 | Openvizsla FPGA-based USB sniffer |
| LINKTYPE_EBHSCR | 279 | Elektrobit High Speed Capture and Replay (EBHSCR) format |
| LINKTYPE_VPP_DISPATCH | 280 | Records in traces from the http://fd.io VPP graph dispatch tracer, in the the graph dispatcher trace format |
| LINKTYPE_DSA_TAG_BRCM | 281 | Ethernet frames, with a switch tag inserted between the source address field and the type/length field in the Ethernet header. |
| LINKTYPE_DSA_TAG_BRCM_PREPEND | 282 | Ethernet frames, with a switch tag inserted before the destination address in the Ethernet header. |
| LINKTYPE_IEEE802_15_4_TAP | 283 | IEEE 802.15.4 Low-Rate Wireless Networks, with a pseudo-header containing TLVs with metadata preceding the 802.15.4 header. |
| LINKTYPE_DSA_TAG_DSA | 284 | Ethernet frames, with a switch tag inserted between the source address field and the type/length field in the Ethernet header. |
| LINKTYPE_DSA_TAG_EDSA | 285 | Ethernet frames, with a programmable Ethernet type switch tag inserted between the source address field and the type/length field in the Ethernet header. |
| LINKTYPE_ELEE | 286 | Payload of lawful intercept packets using the ELEE protocol The packet begins with the ELEE header; it does not include any transport-layer or lower-layer headers for protcols used to transport ELEE packets. |
| LINKTYPE_Z_WAVE_SERIAL | 287 | Serial frames transmitted between a host and a Z-Wave chip over an RS-232 or USB serial connection, as described in section 5 of the Z-Wave Serial API Host Application Programming Guide |
| LINKTYPE_USB_2_0 | 288 | USB 2.0, 1.1, or 1.0 packet, beginning with a PID, as described by Chapter 8 Protocol Layer of the the Universal Serial Bus Specification Revision 2.0 |
| LINKTYPE_ATSC_ALP | 289 | ATSC Link-Layer Protocol frames, as described in section 5 of the A/330 Link-Layer Protocol specification, found at the ATSC 3.0 standards page , beginning with a Base Header |
[Insert pcap developers etc. here].
The authors wish to thank [insert list here] and many others for their invaluable comments.