arch/loongarch/include/asm/checksum.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2016 ARM Ltd.
   4  * Copyright (C) 2023 Loongson Technology Corporation Limited
   5  */
   6 #ifndef __ASM_CHECKSUM_H
   7 #define __ASM_CHECKSUM_H
   8
   9 #include <linux/bitops.h>
  10 #include <linux/in6.h>
  11
  12 #define _HAVE_ARCH_IPV6_CSUM
  13 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  14                         const struct in6_addr *daddr,
  15                         __u32 len, __u8 proto, __wsum sum);
  16
  17 /*
  18  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
  19  * 1's complement 16-bit checksum.
  20  */
  21 static inline __sum16 csum_fold(__wsum sum)
  22 {
  23         u32 tmp = (__force u32)sum;
  24
  25         /*
  26          * swap the two 16-bit halves of sum
  27          * if there is a carry from adding the two 16-bit halves,
  28          * it will carry from the lower half into the upper half,
  29          * giving us the correct sum in the upper half.
  30          */
  31         return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 16);
  32 }
  33 #define csum_fold csum_fold
  34
  35 /*
  36  * This is a version of ip_compute_csum() optimized for IP headers,
  37  * which always checksum on 4 octet boundaries.  ihl is the number
  38  * of 32-bit words and is always >= 5.
  39  */
  40 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  41 {
  42         u64 sum;
  43         __uint128_t tmp;
  44         int n = ihl; /* we want it signed */
  45
  46         tmp = *(const __uint128_t *)iph;
  47         iph += 16;
  48         n -= 4;
  49         tmp += ((tmp >> 64) | (tmp << 64));
  50         sum = tmp >> 64;
  51         do {
  52                 sum += *(const u32 *)iph;
  53                 iph += 4;
  54         } while (--n > 0);
  55
  56         sum += ror64(sum, 32);
  57         return csum_fold((__force __wsum)(sum >> 32));
  58 }
  59 #define ip_fast_csum ip_fast_csum
  60
  61 extern unsigned int do_csum(const unsigned char *buff, int len);
  62 #define do_csum do_csum
  63
  64 #include <asm-generic/checksum.h>
  65
  66 #endif  /* __ASM_CHECKSUM_H */