release/src-rt-6.x.4708/linux/linux-2.6.36/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
  37 static 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
  45 extern __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
  55 static 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
  65 static 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
  78 static inline __sum16 ip_compute_csum(const void *buff, int len)
  79 {
  80         return csum_fold (csum_partial(buff, len, 0));
  81 }
  82
  83 #endif