wlanPCAPWriter

PCAP or PCAPNG file writer of WLAN MAC packets

Since R2021a

Description

The wlanPCAPWriter object writes generated and recovered WLAN medium access control (MAC) packets to a packet capture (PCAP) or packet capture next generation (PCAPNG) file (.pcap or .pcapng, respectively).

Creation

Syntax

obj = wlanPCAPWriter

obj = wlanPCAPWriter(Name,Value)

Description

obj = wlanPCAPWriter creates a default WLAN PCAP or PCAPNG file writer object that writes WLAN MAC packets to a PCAP or PCAPNG file, respectively.

obj = wlanPCAPWriter(Name,Value) sets Properties using one or more name-value pairs. Enclose each property name in quotes. For example, ('FileExtension','pcapng') sets the extension of the file as .pcapng.

Properties

Note

The wlanPCAPWriter object does not overwrite the existing PCAP or PCAPNG file. During each call of this object, specify a unique PCAP or PCAPNG file name.

FileName — Name of the PCAP or PCAPNG file

'wlanCapture' (default) | character row vector | string scalar

Name of the PCAP or PCAPNG file, specified as a character row vector or a string scalar.

Data Types: char | string

ByteOrder — Byte order

'little-endian' (default) | 'big-endian'

Byte order, specified as 'little-endian' or 'big-endian'.

Data Types: char | string

FileExtension — Type of file

'pcap' (default) | 'pcapng'

Type of file, specified as 'pcap' or 'pcapng'.

Data Types: char | string

FileComment — Comment for PCAPNG file

'' (default) | character row vector | string scalar

Comment for the PCAPNG file, specified as a character row vector or a string scalar.

Dependencies

To enable this property, set the FileExtension property to 'pcapng'.

Data Types: char | string

Interface — Name of device that captures WLAN packets

'WLAN' (default) | character row vector | string scalar

Name of device that captures WLAN packets, specified as a character row vector or a string scalar.

Dependencies

To enable this property, set the FileExtension property to 'pcapng'.

Data Types: char | string

RadiotapPresent — Flag to indicate presence of radiotap

false or 0 (default) | true or 1

Flag to indicate the presence of radiotap, specified as a logical 1 (true) or 0 (false).

Data Types: logical

PCAPWriter — PCAP or PCAPNG file writer object

pcapWriter object | pcapngWriter object

PCAP or PCAPNG file writer object, specified as pcapWriter or pcapngWriter object.

Object Functions

Specific to This Object

write

Write protocol packet data to PCAP or PCAPNG file

Examples

Write WLAN MAC Packet to PCAP File

Create a WLAN PCAP file writer object, specifying the name of the PCAP file.

pcapObj = wlanPCAPWriter('FileName','wlanExample', ...
    'FileExtension','pcap');

Generate a WLAN MAC packet of type QoS Data.

macConfig = wlanMACFrameConfig('FrameType','QoS Data');
payload ='00576000103afffe80';
mpdu = wlanMACFrame(payload,macConfig);

Write the WLAN MAC packet to the PCAP file.

timestamp = 0; % Number of microseconds
write(pcapObj,mpdu,timestamp);

Write WLAN MAC Packet to PCAPNG File

Create a WLAN PCAP file writer object, specifying the name of the PCAPNG file.

pcapObj = wlanPCAPWriter('FileName','wlanExample2', ...
    'FileExtension','pcapng');

Generate a WLAN MAC packet of type QoS Data.

macConfig = wlanMACFrameConfig('FrameType','QoS Data');
payload = '00576000103afffe80';
mpdu = wlanMACFrame(payload,macConfig,'OutputFormat','bits');

Write the WLAN MAC packet to the PCAPNG format file.

timestamp = 12800000; % Number of microseconds
write(pcapObj,mpdu,timestamp,'PacketFormat','bits');

Write WLAN MAC Packet to PCAPNG File Using PCAP File Writer

Create a PCAPNG file writer object, specifying the name of the PCAPNG file.

pcapObj = pcapngWriter('FileName','wlanExample3', ...
    'FileComment','This is a sample file');

Create a WLAN PCAP file writer object, specifying the PCAP file writer and the presence of radiotap header.

wlanPCAP = wlanPCAPWriter('PCAPWriter',pcapObj,'RadiotapPresent', ...
    true);

Generate a WLAN MAC packet of type QoS Data.

macConfig = wlanMACFrameConfig('FrameType','QoS Data');
payload = '00576000103afffe80';
mpdu = hex2dec(wlanMACFrame(payload,macConfig));

Write the WLAN MAC packet to the PCAPNG file.

radiotapBytes = [0 0 24 0 2 0 40 0 16 3 0 0 2 192 0 0 0 0 63 1 19 0 0 0];
timestamp = 18912345; % Number of microseconds
write(wlanPCAP,mpdu,timestamp,'Radiotap',radiotapBytes, ...
    'PacketComment','This is the first packet');

References

[1] Tuexen, M. “PCAP Next Generation (Pcapng) Capture File Format.” 2020. https://www.ietf.org/.

[2] “Radiotap - Introduction.” Accessed May 20, 2020. https://www.radiotap.org/.

[3] Group, The Tcpdump. “Tcpdump/Libpcap Public Repository.” Accessed May 20, 2020. https://www.tcpdump.org.

[4] “Development/LibpcapFileFormat - The Wireshark Wiki.” Accessed May 20, 2020. https://www.wireshark.org.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2021a