include/asm-ppc64/checksum.h

   1 #ifndef _PPC64_CHECKSUM_H
   2 #define _PPC64_CHECKSUM_H
   3
   4 /*
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version
   8  * 2 of the License, or (at your option) any later version.
   9  */
  10
  11 /*
  12  * This is a version of ip_compute_csum() optimized for IP headers,
  13  * which always checksum on 4 octet boundaries.  ihl is the number
  14  * of 32-bit words and is always >= 5.
  15  */
  16 extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
  17
  18 /*
  19  * computes the checksum of the TCP/UDP pseudo-header
  20  * returns a 16-bit checksum, already complemented
  21  */
  22 extern unsigned short csum_tcpudp_magic(unsigned long saddr,
  23                                         unsigned long daddr,
  24                                         unsigned short len,
  25                                         unsigned short proto,
  26                                         unsigned int sum);
  27
  28 /*
  29  * computes the checksum of a memory block at buff, length len,
  30  * and adds in "sum" (32-bit)
  31  *
  32  * returns a 32-bit number suitable for feeding into itself
  33  * or csum_tcpudp_magic
  34  *
  35  * this function must be called with even lengths, except
  36  * for the last fragment, which may be odd
  37  *
  38  * it's best to have buff aligned on a 32-bit boundary
  39  */
  40 extern unsigned int csum_partial(const unsigned char * buff, int len,
  41                                  unsigned int sum);
  42
  43 /*
  44  * the same as csum_partial, but copies from src to dst while it
  45  * checksums
  46  */
  47 extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
  48                                               int len, unsigned int sum,
  49                                               int *src_err, int *dst_err);
  50 /*
  51  * the same as csum_partial, but copies from src to dst while it
  52  * checksums.
  53  */
  54
  55 unsigned int csum_partial_copy_nocheck(const char *src,
  56                                        char *dst,
  57                                        int len,
  58                                        unsigned int sum);
  59
  60 /*
  61  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
  62  * 1's complement 16-bit checksum.
  63  */
  64 static inline unsigned int csum_fold(unsigned int sum)
  65 {
  66         unsigned int tmp;
  67
  68         /* swap the two 16-bit halves of sum */
  69         __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
  70         /* if there is a carry from adding the two 16-bit halves,
  71            it will carry from the lower half into the upper half,
  72            giving us the correct sum in the upper half. */
  73         sum = ~(sum + tmp) >> 16;
  74         return sum;
  75 }
  76
  77 /*
  78  * this routine is used for miscellaneous IP-like checksums, mainly
  79  * in icmp.c
  80  */
  81 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
  82 {
  83         return csum_fold(csum_partial(buff, len, 0));
  84 }
  85
  86 #define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
  87         csum_partial_copy_generic((src), (dst), (len), (sum), (errp), NULL)
  88
  89 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  90         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
  91
  92 static inline u32 csum_tcpudp_nofold(u32 saddr,
  93                                      u32 daddr,
  94                                      unsigned short len,
  95                                      unsigned short proto,
  96                                      unsigned int sum)
  97 {
  98         unsigned long s = sum;
  99
 100         s += saddr;
 101         s += daddr;
 102         s += (proto << 16) + len;
 103         s += (s >> 32);
 104         return (u32) s;
 105 }
 106
 107 #endif