LXR linux/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
  21static 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
  29static 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 */
  52