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, __wsum sum, int *err_ptr); 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, 47 int len, __wsum sum, int *err_ptr) 48 { 49 if (access_ok(src, len)) 50 return csum_partial_copy_from_user(src, dst, len, sum, err_ptr); 51 52 if (len) 53 *err_ptr = -EFAULT; 54 55 return sum; 56 } 57 58 /* 59 * Fold a partial checksum without adding pseudo headers 60 */ 61 static inline __sum16 csum_fold(__wsum sum) 62 { 63 __asm__( 64 "add %0, %1, %1, ror #16 @ csum_fold" 65 : "=r" (sum) 66 : "r" (sum) 67 : "cc"); 68 return (__force __sum16)(~(__force u32)sum >> 16); 69 } 70 71 /* 72 * This is a version of ip_compute_csum() optimized for IP headers, 73 * which always checksum on 4 octet boundaries. 74 */ 75 static inline __sum16 76 ip_fast_csum(const void *iph, unsigned int ihl) 77 { 78 unsigned int tmp1; 79 __wsum sum; 80 81 __asm__ __volatile__( 82 "ldr %0, [%1], #4 @ ip_fast_csum \n\ 83 ldr %3, [%1], #4 \n\ 84 sub %2, %2, #5 \n\ 85 adds %0, %0, %3 \n\ 86 ldr %3, [%1], #4 \n\ 87 adcs %0, %0, %3 \n\ 88 ldr %3, [%1], #4 \n\ 89 1: adcs %0, %0, %3 \n\ 90 ldr %3, [%1], #4 \n\ 91 tst %2, #15 @ do this carefully \n\ 92 subne %2, %2, #1 @ without destroying \n\ 93 bne 1b @ the carry flag \n\ 94 adcs %0, %0, %3 \n\ 95 adc %0, %0, #0" 96 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) 97 : "1" (iph), "2" (ihl) 98 : "cc", "memory"); 99 return csum_fold(sum); 100 } 101 102 static inline __wsum 103 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 104 __u8 proto, __wsum sum) 105 { 106 u32 lenprot = len + proto; 107 if (__builtin_constant_p(sum) && sum == 0) { 108 __asm__( 109 "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t" 110 #ifdef __ARMEB__ 111 "adcs %0, %0, %3 \n\t" 112 #else 113 "adcs %0, %0, %3, ror #8 \n\t" 114 #endif 115 "adc %0, %0, #0" 116 : "=&r" (sum) 117 : "r" (daddr), "r" (saddr), "r" (lenprot) 118 : "cc"); 119 } else { 120 __asm__( 121 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t" 122 "adcs %0, %0, %3 \n\t" 123 #ifdef __ARMEB__ 124 "adcs %0, %0, %4 \n\t" 125 #else 126 "adcs %0, %0, %4, ror #8 \n\t" 127 #endif 128 "adc %0, %0, #0" 129 : "=&r"(sum) 130 : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot) 131 : "cc"); 132 } 133 return sum; 134 } 135 /* 136 * computes the checksum of the TCP/UDP pseudo-header 137 * returns a 16-bit checksum, already complemented 138 */ 139 static inline __sum16 140 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 141 __u8 proto, __wsum sum) 142 { 143 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 144 } 145 146 147 /* 148 * this routine is used for miscellaneous IP-like checksums, mainly 149 * in icmp.c 150 */ 151 static inline __sum16 152 ip_compute_csum(const void *buff, int len) 153 { 154 return csum_fold(csum_partial(buff, len, 0)); 155 } 156 157 #define _HAVE_ARCH_IPV6_CSUM 158 extern __wsum 159 __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, 160 __be32 proto, __wsum sum); 161 162 static inline __sum16 163 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, 164 __u32 len, __u8 proto, __wsum sum) 165 { 166 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), 167 htonl(proto), sum)); 168 } 169 #endif 170