1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * arch/arm/include/asm/checksum.h 4 * 5 * IP checksum routines 6 * 7 * Copyright (C) Original authors of ../asm-i386/checksum.h 8 * Copyright (C) 1996-1999 Russell King 9 */ 10 #ifndef __ASM_ARM_CHECKSUM_H 11 #define __ASM_ARM_CHECKSUM_H 12 13 #include <linux/in6.h> 14 15 /* 16 * computes the checksum of a memory block at buff, length len, 17 * and adds in "sum" (32-bit) 18 * 19 * returns a 32-bit number suitable for feeding into itself 20 * or csum_tcpudp_magic 21 * 22 * this function must be called with even lengths, except 23 * for the last fragment, which may be odd 24 * 25 * it's best to have buff aligned on a 32-bit boundary 26 */ 27 __wsum csum_partial(const void *buff, int len, __wsum sum); 28 29 /* 30 * the same as csum_partial, but copies from src while it 31 * checksums, and handles user-space pointer exceptions correctly, when needed. 32 * 33 * here even more important to align src and dst on a 32-bit (or even 34 * better 64-bit) boundary 35 */ 36 37 __wsum 38 csum_partial_copy_nocheck(const void *src, void *dst, int len); 39 40 __wsum 41 csum_partial_copy_from_user(const void __user *src, void *dst, int len); 42 43 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 44 #define _HAVE_ARCH_CSUM_AND_COPY 45 static inline 46 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len) 47 { 48 if (!access_ok(src, len)) 49 return 0; 50 51 return csum_partial_copy_from_user(src, dst, len); 52 } 53 54 /* 55 * Fold a partial checksum without adding pseudo headers 56 */ 57 static inline __sum16 csum_fold(__wsum sum) 58 { 59 __asm__( 60 "add %0, %1, %1, ror #16 @ csum_fold" 61 : "=r" (sum) 62 : "r" (sum) 63 : "cc"); 64 return (__force __sum16)(~(__force u32)sum >> 16); 65 } 66 67 /* 68 * This is a version of ip_compute_csum() optimized for IP headers, 69 * which always checksum on 4 octet boundaries. 70 */ 71 static inline __sum16 72 ip_fast_csum(const void *iph, unsigned int ihl) 73 { 74 unsigned int tmp1; 75 __wsum sum; 76 77 __asm__ __volatile__( 78 "ldr %0, [%1], #4 @ ip_fast_csum \n\ 79 ldr %3, [%1], #4 \n\ 80 sub %2, %2, #5 \n\ 81 adds %0, %0, %3 \n\ 82 ldr %3, [%1], #4 \n\ 83 adcs %0, %0, %3 \n\ 84 ldr %3, [%1], #4 \n\ 85 1: adcs %0, %0, %3 \n\ 86 ldr %3, [%1], #4 \n\ 87 tst %2, #15 @ do this carefully \n\ 88 subne %2, %2, #1 @ without destroying \n\ 89 bne 1b @ the carry flag \n\ 90 adcs %0, %0, %3 \n\ 91 adc %0, %0, #0" 92 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) 93 : "1" (iph), "2" (ihl) 94 : "cc", "memory"); 95 return csum_fold(sum); 96 } 97 98 static inline __wsum 99 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 100 __u8 proto, __wsum sum) 101 { 102 u32 lenprot = len + proto; 103 if (__builtin_constant_p(sum) && sum == 0) { 104 __asm__( 105 "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t" 106 #ifdef __ARMEB__ 107 "adcs %0, %0, %3 \n\t" 108 #else 109 "adcs %0, %0, %3, ror #8 \n\t" 110 #endif 111 "adc %0, %0, #0" 112 : "=&r" (sum) 113 : "r" (daddr), "r" (saddr), "r" (lenprot) 114 : "cc"); 115 } else { 116 __asm__( 117 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t" 118 "adcs %0, %0, %3 \n\t" 119 #ifdef __ARMEB__ 120 "adcs %0, %0, %4 \n\t" 121 #else 122 "adcs %0, %0, %4, ror #8 \n\t" 123 #endif 124 "adc %0, %0, #0" 125 : "=&r"(sum) 126 : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot) 127 : "cc"); 128 } 129 return sum; 130 } 131 /* 132 * computes the checksum of the TCP/UDP pseudo-header 133 * returns a 16-bit checksum, already complemented 134 */ 135 static inline __sum16 136 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 137 __u8 proto, __wsum sum) 138 { 139 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 140 } 141 142 143 /* 144 * this routine is used for miscellaneous IP-like checksums, mainly 145 * in icmp.c 146 */ 147 static inline __sum16 148 ip_compute_csum(const void *buff, int len) 149 { 150 return csum_fold(csum_partial(buff, len, 0)); 151 } 152 153 #define _HAVE_ARCH_IPV6_CSUM 154 extern __wsum 155 __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, 156 __be32 proto, __wsum sum); 157 158 static inline __sum16 159 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, 160 __u32 len, __u8 proto, __wsum sum) 161 { 162 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), 163 htonl(proto), sum)); 164 } 165 #endif 166