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 */ 67