arch/arm64/include/asm/checksum.h

   1 /*
   2  * Copyright (C) 2016 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #ifndef __ASM_CHECKSUM_H
  17 #define __ASM_CHECKSUM_H
  18
  19 #include <linux/types.h>
  20
  21 static inline __sum16 csum_fold(__wsum csum)
  22 {
  23         u32 sum = (__force u32)csum;
  24         sum += (sum >> 16) | (sum << 16);
  25         return ~(__force __sum16)(sum >> 16);
  26 }
  27 #define csum_fold csum_fold
  28
  29 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  30 {
  31         __uint128_t tmp;
  32         u64 sum;
  33
  34         tmp = *(const __uint128_t *)iph;
  35         iph += 16;
  36         ihl -= 4;
  37         tmp += ((tmp >> 64) | (tmp << 64));
  38         sum = tmp >> 64;
  39         do {
  40                 sum += *(const u32 *)iph;
  41                 iph += 4;
  42         } while (--ihl);
  43
  44         sum += ((sum >> 32) | (sum << 32));
  45         return csum_fold((__force u32)(sum >> 32));
  46 }
  47 #define ip_fast_csum ip_fast_csum
  48
  49 #include <asm-generic/checksum.h>
  50
  51 #endif  /* __ASM_CHECKSUM_H */