crc.c File Reference

#include "crc.h"
#include "../misc/byteswap.h"
#include <stdint.h>
#include <sys/types.h>

Go to the source code of this file.

Functions
uint32_t	libwifi_crc32 (const unsigned char *message, int message_len)
	Calculate the CRC32 sum of a given buffer. More...
uint32_t	libwifi_calculate_fcs (const unsigned char *frame, size_t frame_len)
	Calculate the frame checksum for an 802.11 frame. More...
int	libwifi_frame_verify (void *frame, size_t frame_len)
	Check if the given raw 802.11 frame has a valid FCS. More...

Function Documentation

libwifi_calculate_fcs()

uint32_t libwifi_calculate_fcs	(	const unsigned char *	frame,
		size_t	frame_len
	)

Calculate the frame checksum for an 802.11 frame.

Parameters

frame	An 802.11 frame
frame_len	Length of the frame

Returns

frame checksum of the frame

Definition at line 47 of file crc.c.

libwifi_crc32()

uint32_t libwifi_crc32	(	const unsigned char *	message,
		int	message_len
	)

Calculate the CRC32 sum of a given buffer.

Parameters

message	Buffer of data
message_len	Length of the data buffer

Returns

CRC32 sum of the given buffer

Definition at line 26 of file crc.c.

libwifi_frame_verify()

int libwifi_frame_verify	(	void *	frame,
		size_t	frame_len
	)

Check if the given raw 802.11 frame has a valid FCS.

This function relies on an assumption that the last 4 bytes of the supplied frame is the CRC, as stated in the Radiotap specification.

You can check if the frame data has this field by using libwifi_get_wifi_frame() and then checking if the libwifi_frame's flags has the LIBWIFI_FLAGS_FCS_PRESENT bit set.

Parameters

frame	An 802.11 frame with an FCS
frame_len	Length of the frame

Returns

1 if verified, 0 if not

Definition at line 55 of file crc.c.