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

   1#ifndef _METAG_CHECKSUM_H
   2#define _METAG_CHECKSUM_H
   3
   4/*
   5 * computes the checksum of a memory block at buff, length len,
   6 * and adds in "sum" (32-bit)
   7 *
   8 * returns a 32-bit number suitable for feeding into itself
   9 * or csum_tcpudp_magic
  10 *
  11 * this function must be called with even lengths, except
  12 * for the last fragment, which may be odd
  13 *
  14 * it's best to have buff aligned on a 32-bit boundary
  15 */
  16extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  17
  18/*
  19 * the same as csum_partial, but copies from src while it
  20 * checksums
  21 *
  22 * here even more important to align src and dst on a 32-bit (or even
  23 * better 64-bit) boundary
  24 */
  25extern __wsum csum_partial_copy(const void *src, void *dst, int len,
  26                                __wsum sum);
  27
  28/*
  29 * the same as csum_partial_copy, but copies from user space.
  30 *
  31 * here even more important to align src and dst on a 32-bit (or even
  32 * better 64-bit) boundary
  33 */
  34extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  35                                        int len, __wsum sum, int *csum_err);
  36
  37#define csum_partial_copy_nocheck(src, dst, len, sum)   \
  38        csum_partial_copy((src), (dst), (len), (sum))
  39
  40/*
  41 * Fold a partial checksum
  42 */
  43static inline __sum16 csum_fold(__wsum csum)
  44{
  45        u32 sum = (__force u32)csum;
  46        sum = (sum & 0xffff) + (sum >> 16);
  47        sum = (sum & 0xffff) + (sum >> 16);
  48        return (__force __sum16)~sum;
  49}
  50
  51/*
  52 * This is a version of ip_compute_csum() optimized for IP headers,
  53 * which always checksum on 4 octet boundaries.
  54 */
  55extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  56
  57/*
  58 * computes the checksum of the TCP/UDP pseudo-header
  59 * returns a 16-bit checksum, already complemented
  60 */
  61static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  62                                        unsigned short len,
  63                                        unsigned short proto,
  64                                        __wsum sum)
  65{
  66        unsigned long len_proto = (proto + len) << 8;
  67        asm ("ADDS   %0, %0, %1\n"
  68             "ADDCS  %0, %0, #1\n"
  69             "ADDS   %0, %0, %2\n"
  70             "ADDCS  %0, %0, #1\n"
  71             "ADDS   %0, %0, %3\n"
  72             "ADDCS  %0, %0, #1\n"
  73             : "=d" (sum)
  74             : "d" (daddr), "d" (saddr), "d" (len_proto),
  75               "0" (sum)
  76             : "cc");
  77        return sum;
  78}
  79
  80static inline __sum16
  81csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
  82                  unsigned short proto, __wsum sum)
  83{
  84        return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  85}
  86
  87/*
  88 * this routine is used for miscellaneous IP-like checksums, mainly
  89 * in icmp.c
  90 */
  91extern __sum16 ip_compute_csum(const void *buff, int len);
  92
  93#endif /* _METAG_CHECKSUM_H */
  94