include/asm-parisc/checksum.h

   1 #ifndef _PARISC_CHECKSUM_H
   2 #define _PARISC_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 unsigned int csum_partial(const unsigned char *, int, unsigned int);
  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 unsigned int csum_partial_copy(const char *, char *, int, unsigned int);
  26
  27 /*
  28  * the same as csum_partial, but copies from user space
  29  *
  30  * this is obsolete and will go away.
  31  */
  32 #define csum_partial_copy_fromuser csum_partial_copy
  33
  34 /*
  35  * this is a new version of the above that records errors it finds in *errp,
  36  * but continues and zeros the rest of the buffer.
  37  */
  38 unsigned int csum_partial_copy_from_user(const char *src, char *dst, int len, unsigned int sum, int *errp);
  39
  40 /*
  41  *      Note: when you get a NULL pointer exception here this means someone
  42  *      passed in an incorrect kernel address to one of these functions.
  43  *
  44  *      If you use these functions directly please don't forget the
  45  *      verify_area().
  46  */
  47 extern __inline__
  48 unsigned int csum_partial_copy_nocheck (const char *src, char *dst,
  49                                         int len, int sum)
  50 {
  51         return csum_partial_copy (src, dst, len, sum);
  52 }
  53
  54 /*
  55  *      Optimized for IP headers, which always checksum on 4 octet boundaries.
  56  *
  57  *      Written by Randolph Chung <tausq@debian.org>
  58  */
  59 static inline unsigned short ip_fast_csum(unsigned char * iph,
  60                                           unsigned int ihl) {
  61         unsigned int sum;
  62
  63
  64         __asm__ __volatile__ ("
  65         ldws,ma         4(%1), %0
  66         addi            -4, %2, %2
  67         comib,>=        0, %2, 2f
  68
  69         ldws,ma         4(%1), %%r19
  70         add             %0, %%r19, %0
  71         ldws,ma         4(%1), %%r19
  72         addc            %0, %%r19, %0
  73         ldws,ma         4(%1), %%r19
  74         addc            %0, %%r19, %0
  75 1:      ldws,ma         4(%1), %%r19
  76         addib,<>        -1, %2, 1b
  77         addc            %0, %%r19, %0
  78         addc            %0, %%r0, %0
  79
  80         zdepi           -1, 31, 16, %%r19
  81         and             %0, %%r19, %%r20
  82         extru           %0, 15, 16, %%r21
  83         add             %%r20, %%r21, %0
  84         and             %0, %%r19, %%r20
  85         extru           %0, 15, 16, %%r21
  86         add             %%r20, %%r21, %0
  87         subi            -1, %0, %0
  88 2:
  89         "
  90         : "=r" (sum), "=r" (iph), "=r" (ihl)
  91         : "1" (iph), "2" (ihl)
  92         : "r19", "r20", "r21" );
  93
  94         return(sum);
  95 }
  96
  97 /*
  98  *      Fold a partial checksum
  99  */
 100 static inline unsigned int csum_fold(unsigned int sum)
 101 {
 102         sum = (sum & 0xffff) + (sum >> 16);
 103         sum = (sum & 0xffff) + (sum >> 16);
 104         return ~sum;
 105 }
 106
 107 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
 108                                                unsigned long daddr,
 109                                                unsigned short len,
 110                                                unsigned short proto,
 111                                                unsigned int sum)
 112 {
 113         __asm__("
 114                 add  %1, %0, %0
 115                 addc %2, %0, %0
 116                 addc %3, %0, %0
 117                 addc %%r0, %0, %0 "
 118                 : "=r" (sum)
 119                 : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
 120     return sum;
 121 }
 122
 123 /*
 124  * computes the checksum of the TCP/UDP pseudo-header
 125  * returns a 16-bit checksum, already complemented
 126  */
 127 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
 128                                                    unsigned long daddr,
 129                                                    unsigned short len,
 130                                                    unsigned short proto,
 131                                                    unsigned int sum)
 132 {
 133         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 134 }
 135
 136 /*
 137  * this routine is used for miscellaneous IP-like checksums, mainly
 138  * in icmp.c
 139  */
 140 static inline unsigned short ip_compute_csum(unsigned char * buf, int len) {
 141          return csum_fold (csum_partial(buf, len, 0));
 142 }
 143
 144 #define _HAVE_ARCH_IPV6_CSUM
 145 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 146                                                      struct in6_addr *daddr,
 147                                                      __u16 len,
 148                                                      unsigned short proto,
 149                                                      unsigned int sum)
 150 {
 151         BUG();
 152         return csum_fold(sum);
 153 }
 154
 155 /*
 156  *      Copy and checksum to user
 157  */
 158 #define HAVE_CSUM_COPY_USER
 159 static __inline__ unsigned int csum_and_copy_to_user (const char *src, char *dst,
 160                                     int len, int sum, int *err_ptr)
 161 {
 162         /* code stolen from include/asm-mips64 */
 163         sum = csum_partial(src, len, sum);
 164
 165         if (copy_to_user(dst, src, len)) {
 166                 *err_ptr = -EFAULT;
 167                 return -1;
 168         }
 169
 170         return sum;
 171 }
 172
 173 #endif
 174