lwIP  2.1.0
Lightweight IP stack
inet_chksum.c File Reference
#include "lwip/opt.h"
#include "lwip/inet_chksum.h"
#include "lwip/def.h"
#include "lwip/ip_addr.h"
#include <string.h>

Functions

u16_t ip6_chksum_pseudo (struct pbuf *p, u8_t proto, u16_t proto_len, const ip6_addr_t *src, const ip6_addr_t *dest)
 
u16_t ip6_chksum_pseudo_partial (struct pbuf *p, u8_t proto, u16_t proto_len, u16_t chksum_len, const ip6_addr_t *src, const ip6_addr_t *dest)
 
u16_t inet_chksum_pbuf (struct pbuf *p)
 

Detailed Description

Internet checksum functions.
These are some reference implementations of the checksum algorithm, with the aim of being simple, correct and fully portable. Checksumming is the first thing you would want to optimize for your platform. If you create your own version, link it in and in your cc.h put:

#define LWIP_CHKSUM your_checksum_routine

Or you can select from the implementations below by defining LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.

Function Documentation

◆ inet_chksum_pbuf()

u16_t inet_chksum_pbuf ( struct pbuf p)

Calculate a checksum over a chain of pbufs (without pseudo-header, much like inet_chksum only pbufs are used).

Parameters
ppbuf chain over that the checksum should be calculated
Returns
checksum (as u16_t) to be saved directly in the protocol header

◆ ip6_chksum_pseudo()

u16_t ip6_chksum_pseudo ( struct pbuf p,
u8_t  proto,
u16_t  proto_len,
const ip6_addr_t src,
const ip6_addr_t dest 
)

Calculates the checksum with IPv6 pseudo header used by TCP and UDP for a pbuf chain. IPv6 addresses are expected to be in network byte order.

Parameters
pchain of pbufs over that a checksum should be calculated (ip data part)
protoipv6 protocol/next header (used for checksum of pseudo header)
proto_lenlength of the ipv6 payload (used for checksum of pseudo header)
srcsource ipv6 address (used for checksum of pseudo header)
destdestination ipv6 address (used for checksum of pseudo header)
Returns
checksum (as u16_t) to be saved directly in the protocol header

◆ ip6_chksum_pseudo_partial()

u16_t ip6_chksum_pseudo_partial ( struct pbuf p,
u8_t  proto,
u16_t  proto_len,
u16_t  chksum_len,
const ip6_addr_t src,
const ip6_addr_t dest 
)

Calculates the checksum with IPv6 pseudo header used by TCP and UDP for a pbuf chain. IPv6 addresses are expected to be in network byte order. Will only compute for a portion of the payload.

Parameters
pchain of pbufs over that a checksum should be calculated (ip data part)
protoipv6 protocol/next header (used for checksum of pseudo header)
proto_lenlength of the ipv6 payload (used for checksum of pseudo header)
chksum_lennumber of payload bytes used to compute chksum
srcsource ipv6 address (used for checksum of pseudo header)
destdestination ipv6 address (used for checksum of pseudo header)
Returns
checksum (as u16_t) to be saved directly in the protocol header