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  */
  16 extern __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  */
  25 extern __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  */
  34 extern __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  */
  43 static 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  */
  55 extern __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  */
  61 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  62                                         __u32 len, __u8 proto,
  63                                         __wsum sum)
  64 {
  65         unsigned long len_proto = (proto + len) << 8;
  66         asm ("ADDS   %0, %0, %1\n"
  67              "ADDCS  %0, %0, #1\n"
  68              "ADDS   %0, %0, %2\n"
  69              "ADDCS  %0, %0, #1\n"
  70              "ADDS   %0, %0, %3\n"
  71              "ADDCS  %0, %0, #1\n"
  72              : "=d" (sum)
  73              : "d" (daddr), "d" (saddr), "d" (len_proto),
  74                "0" (sum)
  75              : "cc");
  76         return sum;
  77 }
  78
  79 static inline __sum16
  80 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
  81                   __u8 proto, __wsum sum)
  82 {
  83         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  84 }
  85
  86 /*
  87  * this routine is used for miscellaneous IP-like checksums, mainly
  88  * in icmp.c
  89  */
  90 extern __sum16 ip_compute_csum(const void *buff, int len);
  91
  92 #endif /* _METAG_CHECKSUM_H */