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 */
csum_fold(__wsum sum)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 */
ip_fast_csum(const void * iph,unsigned int ihl)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 */
67
