Network utility functions and macros
[Protocol stack]

---

Detailed Description

This module provides some helper functions and macros used throughout the network stack.

Files
file	net.c
	Network utility functions (license: GPLv2).
file	net.h
	Network utility header (license: GPLv2).
Defines
#define	HTON16(val)
	Converts a 16-bit integer to network byte order.
#define	HTON32(val)
	Converts a 32-bit integer to network byte order.
#define	NTOH16(val)
	Converts a 16-bit integer to host byte order.
#define	NTOH32(val)
	Converts a 32-bit integer to host byte order.
#define	NET_HEADER_SIZE_ETHERNET
	The size of an ethernet header.
#define	NET_HEADER_SIZE_IP
	The size of an IP header.
#define	NET_HEADER_SIZE_TCP
	The size of a TCP header.
#define	NET_HEADER_SIZE_UDP
	The size of a UDP header.
#define	ntoh16(n)
	Converts a 16-bit integer to host byte order.
#define	ntoh32(n)
	Converts a 32-bit integer to host byte order.
Functions
uint16_t	net_calc_checksum (uint16_t checksum, const uint8_t *data, uint16_t data_len, uint8_t skip)
	Generic Internet checksum implementation.
uint16_t	hton16 (uint16_t h)
	Converts a 16-bit integer to network byte order.
uint32_t	hton32 (uint32_t h)
	Converts a 32-bit integer to network byte order.

---

Define Documentation

#define HTON16

(

val

)

Converts a 16-bit integer to network byte order.

Use this macro for compile time constants only. For variable values use the function hton16() instead. This saves code size.

Parameters:

[in]

val

A 16-bit integer in host byte order.

Returns:

The given 16-bit integer converted to network byte order.

#define HTON32

(

val

)

Converts a 32-bit integer to network byte order.

Use this macro for compile time constants only. For variable values use the function hton32() instead. This saves code size.

Parameters:

[in]

val

A 32-bit integer in host byte order.

Returns:

The given 32-bit integer converted to network byte order.

#define NTOH16

(

val

)

Converts a 16-bit integer to host byte order.

Use this macro for compile time constants only. For variable values use the function ntoh16() instead. This saves code size.

Parameters:

[in]

val

A 16-bit integer in network byte order.

Returns:

The given 16-bit integer converted to host byte order.

#define NTOH32

(

val

)

Converts a 32-bit integer to host byte order.

Use this macro for compile time constants only. For variable values use the function ntoh32() instead. This saves code size.

Parameters:

[in]

val

A 32-bit integer in network byte order.

Returns:

The given 32-bit integer converted to host byte order.

#define NET_HEADER_SIZE_ETHERNET

The size of an ethernet header.

#define NET_HEADER_SIZE_IP

The size of an IP header.

#define NET_HEADER_SIZE_TCP

The size of a TCP header.

#define NET_HEADER_SIZE_UDP

The size of a UDP header.

#define ntoh16

(

n

)

Converts a 16-bit integer to host byte order.

Use this function on variable values instead of the macro NTOH16(). This saves code size.

Parameters:

[in]

n

A 16-bit integer in network byte order.

Returns:

The given 16-bit integer converted to host byte order.

#define ntoh32

(

n

)

Converts a 32-bit integer to host byte order.

Use this function on variable values instead of the macro NTOH32(). This saves code size.

Parameters:

[in]

n

A 32-bit integer in network byte order.

Returns:

The given 32-bit integer converted to host byte order.

---

Function Documentation

uint16_t net_calc_checksum	(	uint16_t	checksum,
		const uint8_t *	data,
		uint16_t	data_len,
		uint8_t	skip
	)

Generic Internet checksum implementation.

Calculates the Internet checksum over some arbitrary data block. Updating the checksum is possible by providing the checksum of some previous data.

Parameters:

[in]	checksum	The checksum value to start from. Should be zero for the first byte.
[in]	data	A pointer to the buffer containing the data to be checksummed.
[in]	data_len	The number of bytes to be checksummed.
[in]	skip	The position of a two-bytes-value assumed to be zero during checksum calculation.

Returns:

The inverted checksum value.

uint16_t hton16

(

uint16_t

h

)

Converts a 16-bit integer to network byte order.

Use this function on variable values instead of the macro HTON16(). This saves code size.

Parameters:

[in]

h

A 16-bit integer in host byte order.

Returns:

The given 16-bit integer converted to network byte order.

uint32_t hton32

(

uint32_t

h

)

Converts a 32-bit integer to network byte order.

Use this function on variable values instead of the macro HTON32(). This saves code size.

Parameters:

[in]

h

A 32-bit integer in host byte order.

Returns:

The given 32-bit integer converted to network byte order.