P4::NetHash Namespace Reference

A collection of hashing functions commonly used in network protocols. More...

Classes
struct	Identity
	A class with the same signature as reflect, but just returning the data. More...
struct	Reflect

Functions
uint16_t	crc16 (const uint8_t *buf, size_t len)
	CRC-16 used in BMv2 (parameters: bit-reflection, polynomial 0x8005, init = 0 and xor_out = 0).
uint16_t	crc16ANSI (const uint8_t *buf, size_t len)
uint32_t	crc32 (const uint8_t *buf, size_t len)
uint32_t	crc32FCS (const uint8_t *buf, size_t len)
uint16_t	crcCCITT (const uint8_t *buf, size_t len)
	CRC16-CCITT (parameters: NO bit-reflection, polynomial 0x1021, init = ~0 and xor_out = 0).
template<typename T , T remainderInit, T final_xor_value, auto table, typename MaybeReflect >
T	crcGeneric (const uint8_t *buf, size_t len)
uint16_t	csum16 (const uint8_t *buf, size_t len)
	16-bit ones' complement checksum (used in IP, TCP, UDP, ...).
uint64_t	identity (const uint8_t *buf, size_t len)
	Identity hash – the first (up to) 64bits of the values (i.e. indexes 0 to 7).
uint16_t	xor16 (const uint8_t *buf, size_t len)
	A 16-bit xor of the values.

Detailed Description

A collection of hashing functions commonly used in network protocols.

Function Documentation

crc16ANSI()

uint16_t P4::NetHash::crc16ANSI	(	const uint8_t *	buf,
		size_t	len )

CRC-16-ANSI/CRC-16-IBM (parameters: NO bit-reflection, polynomial 0x8005, init = 0 and xor_out = 0).

crc32()

uint32_t P4::NetHash::crc32	(	const uint8_t *	buf,
		size_t	len )

CRC-32, used in BMv2 (parameters: bit-reflection, polynomial 0x04C11DB7, init = ~0 and xor_out = ~0).

crc32FCS()

uint32_t P4::NetHash::crc32FCS	(	const uint8_t *	buf,
		size_t	len )

CRC-32 used for Ethernet FCS (parameters: NO bit-reflection, polynomial 0x04C11DB7, init = ~0 and xor_out = ~0).