LXR linux/arch/cris/include/asm/checksum.h

   1/* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
   2
   3#ifndef _CRIS_CHECKSUM_H
   4#define _CRIS_CHECKSUM_H
   5
   6#include <arch/checksum.h>
   7
   8/*
   9 * computes the checksum of a memory block at buff, length len,
  10 * and adds in "sum" (32-bit)
  11 *
  12 * returns a 32-bit number suitable for feeding into itself
  13 * or csum_tcpudp_magic
  14 *
  15 * this function must be called with even lengths, except
  16 * for the last fragment, which may be odd
  17 *
  18 * it's best to have buff aligned on a 32-bit boundary
  19 */
  20__wsum csum_partial(const void *buff, int len, __wsum sum);
  21
  22/*
  23 * the same as csum_partial, but copies from src while it
  24 * checksums
  25 *
  26 * here even more important to align src and dst on a 32-bit (or even
  27 * better 64-bit) boundary
  28 */
  29
  30__wsum csum_partial_copy_nocheck(const void *src, void *dst,
  31                                       int len, __wsum sum);
  32
  33/*
  34 *      Fold a partial checksum into a word
  35 */
  36
  37static inline __sum16 csum_fold(__wsum csum)
  38{
  39        u32 sum = (__force u32)csum;
  40        sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
  41        sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
  42        return (__force __sum16)~sum;
  43}
  44
  45extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  46                                                int len, __wsum sum,
  47                                                int *errptr);
  48
  49/*
  50 *      This is a version of ip_compute_csum() optimized for IP headers,
  51 *      which always checksum on 4 octet boundaries.
  52 *
  53 */
  54
  55static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  56{
  57        return csum_fold(csum_partial(iph, ihl * 4, 0));
  58}
  59 
  60/*
  61 * computes the checksum of the TCP/UDP pseudo-header
  62 * returns a 16-bit checksum, already complemented
  63 */
  64
  65static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  66                                                   unsigned short len,
  67                                                   unsigned short proto,
  68                                                   __wsum sum)
  69{
  70        return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
  71}
  72
  73/*
  74 * this routine is used for miscellaneous IP-like checksums, mainly
  75 * in icmp.c
  76 */
  77
  78static inline __sum16 ip_compute_csum(const void *buff, int len)
  79{
  80        return csum_fold (csum_partial(buff, len, 0));
  81}
  82
  83#endif
  84