arch/sh64/lib/c-checksum.c

   1 /*
   2  * arch/sh/lib/csum_parial.c
   3  *
   4  * This file contains network checksum routines that are better done
   5  * in an architecture-specific manner due to speed..
   6  */
   7
   8 #undef DEBUG
   9
  10 #include <linux/config.h>
  11 #include <linux/string.h>
  12 #include <linux/errno.h>
  13 #include <linux/kernel.h>
  14 #include <asm/byteorder.h>
  15 #include <asm/uaccess.h>
  16
  17 static inline unsigned short from64to16(unsigned long long x)
  18 {
  19         /* add up 32-bit words for 33 bits */
  20         x = (x & 0xffffffff) + (x >> 32);
  21         /* add up 16-bit and 17-bit words for 17+c bits */
  22         x = (x & 0xffff) + (x >> 16);
  23         /* add up 16-bit and 2-bit for 16+c bit */
  24         x = (x & 0xffff) + (x >> 16);
  25         /* add up carry.. */
  26         x = (x & 0xffff) + (x >> 16);
  27         return x;
  28 }
  29
  30 static inline unsigned short foldto16(unsigned long x)
  31 {
  32         /* add up 16-bit for 17 bits */
  33         x = (x & 0xffff) + (x >> 16);
  34         /* add up carry.. */
  35         x = (x & 0xffff) + (x >> 16);
  36         return x;
  37 }
  38
  39 static inline unsigned short myfoldto16(unsigned long long x)
  40 {
  41         /* Fold down to 32-bits so we don't loose in the typedef-less
  42            network stack.  */
  43         /* 64 to 33 */
  44         x = (x & 0xffffffff) + (x >> 32);
  45         /* 33 to 32 */
  46         x = (x & 0xffffffff) + (x >> 32);
  47
  48         /* add up 16-bit for 17 bits */
  49         x = (x & 0xffff) + (x >> 16);
  50         /* add up carry.. */
  51         x = (x & 0xffff) + (x >> 16);
  52         return x;
  53 }
  54
  55 #define odd(x) ((x)&1)
  56 #define U16(x) ntohs(x)
  57
  58 static unsigned long do_csum(const unsigned char *buff, int len)
  59 {
  60         int odd, count;
  61         unsigned long result = 0;
  62
  63         pr_debug("do_csum buff %p, len %d (0x%x)\n", buff, len, len);
  64 #ifdef DEBUG
  65         for (i = 0; i < len; i++) {
  66                 if ((i % 26) == 0)
  67                         printk("\n");
  68                 printk("%02X ", buff[i]);
  69         }
  70 #endif
  71
  72         if (len <= 0)
  73                 goto out;
  74
  75         odd = 1 & (unsigned long) buff;
  76         if (odd) {
  77                 result = *buff << 8;
  78                 len--;
  79                 buff++;
  80         }
  81         count = len >> 1;       /* nr of 16-bit words.. */
  82         if (count) {
  83                 if (2 & (unsigned long) buff) {
  84                         result += *(unsigned short *) buff;
  85                         count--;
  86                         len -= 2;
  87                         buff += 2;
  88                 }
  89                 count >>= 1;    /* nr of 32-bit words.. */
  90                 if (count) {
  91                         unsigned long carry = 0;
  92                         do {
  93                                 unsigned long w = *(unsigned long *) buff;
  94                                 buff += 4;
  95                                 count--;
  96                                 result += carry;
  97                                 result += w;
  98                                 carry = (w > result);
  99                         } while (count);
 100                         result += carry;
 101                         result = (result & 0xffff) + (result >> 16);
 102                 }
 103                 if (len & 2) {
 104                         result += *(unsigned short *) buff;
 105                         buff += 2;
 106                 }
 107         }
 108         if (len & 1)
 109                 result += *buff;
 110         result = foldto16(result);
 111         if (odd)
 112                 result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
 113
 114         pr_debug("\nCHECKSUM is 0x%x\n", result);
 115
 116       out:
 117         return result;
 118 }
 119
 120 /* computes the checksum of a memory block at buff, length len,
 121    and adds in "sum" (32-bit)  */
 122 unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum)
 123 {
 124         unsigned long long result = do_csum(buff, len);
 125
 126         /* add in old sum, and carry.. */
 127         result += sum;
 128         /* 32+c bits -> 32 bits */
 129         result = (result & 0xffffffff) + (result >> 32);
 130
 131         pr_debug("csum_partial, buff %p len %d sum 0x%x result=0x%016Lx\n",
 132                 buff, len, sum, result);
 133
 134         return result;
 135 }
 136
 137 /* Copy while checksumming, otherwise like csum_partial.  */
 138 unsigned int
 139 csum_partial_copy(const unsigned char *src, unsigned char *dst, int len, unsigned int sum)
 140 {
 141         sum = csum_partial(src, len, sum);
 142         memcpy(dst, src, len);
 143
 144         return sum;
 145 }
 146
 147 /* Copy from userspace and compute checksum.  If we catch an exception
 148    then zero the rest of the buffer.  */
 149 unsigned int
 150 csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len,
 151                             unsigned int sum, int *err_ptr)
 152 {
 153         int missing;
 154
 155         pr_debug
 156             ("csum_partial_copy_from_user src %p, dest %p, len %d, sum %08x, err_ptr %p\n",
 157              src, dst, len, sum, err_ptr);
 158         missing = copy_from_user(dst, src, len);
 159         pr_debug("  access_ok %d\n", __access_ok((unsigned long) src, len));
 160         pr_debug("  missing %d\n", missing);
 161         if (missing) {
 162                 memset(dst + len - missing, 0, missing);
 163                 *err_ptr = -EFAULT;
 164         }
 165
 166         return csum_partial(dst, len, sum);
 167 }
 168
 169 /* Copy to userspace and compute checksum.  */
 170 unsigned int
 171 csum_partial_copy_to_user(const unsigned char *src, unsigned char *dst, int len,
 172                           unsigned int sum, int *err_ptr)
 173 {
 174         sum = csum_partial(src, len, sum);
 175
 176         if (copy_to_user(dst, src, len))
 177                 *err_ptr = -EFAULT;
 178
 179         return sum;
 180 }
 181
 182 /*
 183  *      This is a version of ip_compute_csum() optimized for IP headers,
 184  *      which always checksum on 4 octet boundaries.
 185  */
 186 unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
 187 {
 188         pr_debug("ip_fast_csum %p,%d\n", iph, ihl);
 189
 190         return ~do_csum(iph, ihl * 4);
 191 }
 192
 193 unsigned int csum_tcpudp_nofold(unsigned long saddr,
 194                                 unsigned long daddr,
 195                                 unsigned short len,
 196                                 unsigned short proto, unsigned int sum)
 197 {
 198         unsigned long long result;
 199
 200         pr_debug("ntohs(0x%x)=0x%x\n", 0xdead, ntohs(0xdead));
 201         pr_debug("htons(0x%x)=0x%x\n", 0xdead, htons(0xdead));
 202
 203         result = ((unsigned long long) saddr +
 204                   (unsigned long long) daddr +
 205                   (unsigned long long) sum +
 206                   ((unsigned long long) ntohs(len) << 16) +
 207                   ((unsigned long long) proto << 8));
 208
 209         /* Fold down to 32-bits so we don't loose in the typedef-less
 210            network stack.  */
 211         /* 64 to 33 */
 212         result = (result & 0xffffffff) + (result >> 32);
 213         /* 33 to 32 */
 214         result = (result & 0xffffffff) + (result >> 32);
 215
 216         pr_debug("%s saddr %x daddr %x len %x proto %x sum %x result %08Lx\n",
 217                 __FUNCTION__, saddr, daddr, len, proto, sum, result);
 218
 219         return result;
 220 }
 221
 222 // Post SIM:
 223 unsigned int
 224 csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len, unsigned int sum)
 225 {
 226         //  unsigned dummy;
 227         pr_debug("csum_partial_copy_nocheck src %p dst %p len %d\n", src, dst,
 228                 len);
 229
 230         return csum_partial_copy(src, dst, len, sum);
 231 }