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, __wsum sum); 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 static inline 45 __wsum csum_and_copy_from_user (const void __user *src, void *dst, 46 int len, __wsum sum, int *err_ptr) 47 { 48 if (access_ok(src, len)) 49 return csum_partial_copy_from_user(src, dst, len, sum, err_ptr); 50 51 if (len) 52 *err_ptr = -EFAULT; 53 54 return sum; 55 } 56 57 /* 58 * Fold a partial checksum without adding pseudo headers 59 */ 60 static inline __sum16 csum_fold(__wsum sum) 61 { 62 __asm__( 63 "add %0, %1, %1, ror #16 @ csum_fold" 64 : "=r" (sum) 65 : "r" (sum) 66 : "cc"); 67 return (__force __sum16)(~(__force u32)sum >> 16); 68 } 69 70 /* 71 * This is a version of ip_compute_csum() optimized for IP headers, 72 * which always checksum on 4 octet boundaries. 73 */ 74 static inline __sum16 75 ip_fast_csum(const void *iph, unsigned int ihl) 76 { 77 unsigned int tmp1; 78 __wsum sum; 79 80 __asm__ __volatile__( 81 "ldr %0, [%1], #4 @ ip_fast_csum \n\ 82 ldr %3, [%1], #4 \n\ 83 sub %2, %2, #5 \n\ 84 adds %0, %0, %3 \n\ 85 ldr %3, [%1], #4 \n\ 86 adcs %0, %0, %3 \n\ 87 ldr %3, [%1], #4 \n\ 88 1: adcs %0, %0, %3 \n\ 89 ldr %3, [%1], #4 \n\ 90 tst %2, #15 @ do this carefully \n\ 91 subne %2, %2, #1 @ without destroying \n\ 92 bne 1b @ the carry flag \n\ 93 adcs %0, %0, %3 \n\ 94 adc %0, %0, #0" 95 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) 96 : "1" (iph), "2" (ihl) 97 : "cc", "memory"); 98 return csum_fold(sum); 99 } 100 101 static inline __wsum 102 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 103 __u8 proto, __wsum sum) 104 { 105 u32 lenprot = len + proto; 106 if (__builtin_constant_p(sum) && sum == 0) { 107 __asm__( 108 "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t" 109 #ifdef __ARMEB__ 110 "adcs %0, %0, %3 \n\t" 111 #else 112 "adcs %0, %0, %3, ror #8 \n\t" 113 #endif 114 "adc %0, %0, #0" 115 : "=&r" (sum) 116 : "r" (daddr), "r" (saddr), "r" (lenprot) 117 : "cc"); 118 } else { 119 __asm__( 120 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t" 121 "adcs %0, %0, %3 \n\t" 122 #ifdef __ARMEB__ 123 "adcs %0, %0, %4 \n\t" 124 #else 125 "adcs %0, %0, %4, ror #8 \n\t" 126 #endif 127 "adc %0, %0, #0" 128 : "=&r"(sum) 129 : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot) 130 : "cc"); 131 } 132 return sum; 133 } 134 /* 135 * computes the checksum of the TCP/UDP pseudo-header 136 * returns a 16-bit checksum, already complemented 137 */ 138 static inline __sum16 139 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 140 __u8 proto, __wsum sum) 141 { 142 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 143 } 144 145 146 /* 147 * this routine is used for miscellaneous IP-like checksums, mainly 148 * in icmp.c 149 */ 150 static inline __sum16 151 ip_compute_csum(const void *buff, int len) 152 { 153 return csum_fold(csum_partial(buff, len, 0)); 154 } 155 156 #define _HAVE_ARCH_IPV6_CSUM 157 extern __wsum 158 __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, 159 __be32 proto, __wsum sum); 160 161 static inline __sum16 162 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, 163 __u32 len, __u8 proto, __wsum sum) 164 { 165 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), 166 htonl(proto), sum)); 167 } 168 #endif 169