inet6.c File Reference

#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/inet.h"

Include dependency graph for inet6.c:

Go to the source code of this file.

Functions
static u32_t	chksum (void *dataptr, u16_t len)
u16_t	inet_chksum_pseudo (struct pbuf *p, struct ip_addr *src, struct ip_addr *dest, u8_t proto, u32_t proto_len)
u16_t	inet_chksum (void *dataptr, u16_t len)
u16_t	inet_chksum_pbuf (struct pbuf *p)

Detailed Description

Functions common to all TCP/IPv6 modules, such as the Internet checksum and the byte order functions.

Definition in file inet6.c.

Function Documentation

chksum()

static u32_t chksum ( void *  dataptr, u16_t  len  )

static

Definition at line 55 of file inet6.c.

{
  u16_t *sdataptr = dataptr;
  u32_t acc;
 
 
  for(acc = 0; len > 1; len -= 2) {
    acc += *sdataptr++;
  }
 
  /* add up any odd byte */
  if (len == 1) {
    acc += htons((u16_t)(*(u8_t *)dataptr) << 8);
  }
 
  return acc;
 
}

Referenced by GetPrivateProfileStructW(), inet_chksum(), inet_chksum_pbuf(), and inet_chksum_pseudo().

inet_chksum()

u16_t inet_chksum	(	void *	dataptr,
		u16_t	len
	)

Definition at line 129 of file inet6.c.

{
  u32_t acc, sum;
 
  acc = chksum(dataptr, len);
  sum = (acc & 0xffff) + (acc >> 16);
  sum += (sum >> 16);
  return ~(sum & 0xffff);
}

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

p	pbuf chain over that the checksum should be calculated

Returns

checksum (as u16_t) to be saved directly in the protocol header

Definition at line 140 of file inet6.c.

{
  u32_t acc;
  struct pbuf *q;
  u8_t swapped;
 
  acc = 0;
  swapped = 0;
  for(q = p; q != NULL; q = q->next) {
    acc += chksum(q->payload, q->len);
    while (acc >> 16) {
      acc = (acc & 0xffff) + (acc >> 16);
    }
    if (q->len % 2 != 0) {
      swapped = 1 - swapped;
      acc = (acc & 0xff << 8) | (acc & 0xff00 >> 8);
    }
  }
 
  if (swapped) {
    acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
  }
  return ~(acc & 0xffff);
}

inet_chksum_pseudo()

u16_t inet_chksum_pseudo	(	struct pbuf *	p,
		struct ip_addr *	src,
		struct ip_addr *	dest,
		u8_t	proto,
		u32_t	proto_len
	)

Definition at line 80 of file inet6.c.

{
  u32_t acc;
  struct pbuf *q;
  u8_t swapped, i;
 
  acc = 0;
  swapped = 0;
  for(q = p; q != NULL; q = q->next) {
    acc += chksum(q->payload, q->len);
    while (acc >> 16) {
      acc = (acc & 0xffff) + (acc >> 16);
    }
    if (q->len % 2 != 0) {
      swapped = 1 - swapped;
      acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
    }
  }
 
  if (swapped) {
    acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
  }
 
  for(i = 0; i < 8; i++) {
    acc += ((u16_t *)src->addr)[i] & 0xffff;
    acc += ((u16_t *)dest->addr)[i] & 0xffff;
    while (acc >> 16) {
      acc = (acc & 0xffff) + (acc >> 16);
    }
  }
  acc += (u16_t)htons((u16_t)proto);
  acc += ((u16_t *)&proto_len)[0] & 0xffff;
  acc += ((u16_t *)&proto_len)[1] & 0xffff;
 
  while (acc >> 16) {
    acc = (acc & 0xffff) + (acc >> 16);
  }
  return ~(acc & 0xffff);
}