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 #include <linux/uaccess.h> 15 16 /* 17 * computes the checksum of a memory block at buff, length len, 18 * and adds in "sum" (32-bit) 19 * 20 * returns a 32-bit number suitable for feeding into itself 21 * or csum_tcpudp_magic 22 * 23 * this function must be called with even lengths, except 24 * for the last fragment, which may be odd 25 * 26 * it's best to have buff aligned on a 32-bit boundary 27 */ 28 __wsum csum_partial(const void *buff, int len, __wsum sum); 29 30 /* 31 * the same as csum_partial, but copies from src while it 32 * checksums, and handles user-space pointer exceptions correctly, when needed. 33 * 34 * here even more important to align src and dst on a 32-bit (or even 35 * better 64-bit) boundary 36 */ 37 38 __wsum 39 csum_partial_copy_nocheck(const void *src, void *dst, int len); 40 41 __wsum 42 csum_partial_copy_from_user(const void __user *src, void *dst, int len); 43 44 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 45 #define _HAVE_ARCH_CSUM_AND_COPY 46 static inline 47 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len) 48 { 49 if (!access_ok(src, len)) 50 return 0; 51 52 return csum_partial_copy_from_user(src, dst, len); 53 } 54 55 /* 56 * Fold a partial checksum without adding pseudo headers 57 */ 58 static inline __sum16 csum_fold(__wsum sum) 59 { 60 __asm__( 61 "add %0, %1, %1, ror #16 @ csum_fold" 62 : "=r" (sum) 63 : "r" (sum) 64 : "cc"); 65 return (__force __sum16)(~(__force u32)sum >> 16); 66 } 67 68 /* 69 * This is a version of ip_compute_csum() optimized for IP headers, 70 * which always checksum on 4 octet boundaries. 71 */ 72 static inline __sum16 73 ip_fast_csum(const void *iph, unsigned int ihl) 74 { 75 unsigned int tmp1; 76 __wsum sum; 77 78 __asm__ __volatile__( 79 "ldr %0, [%1], #4 @ ip_fast_csum \n\ 80 ldr %3, [%1], #4 \n\ 81 sub %2, %2, #5 \n\ 82 adds %0, %0, %3 \n\ 83 ldr %3, [%1], #4 \n\ 84 adcs %0, %0, %3 \n\ 85 ldr %3, [%1], #4 \n\ 86 1: adcs %0, %0, %3 \n\ 87 ldr %3, [%1], #4 \n\ 88 tst %2, #15 @ do this carefully \n\ 89 subne %2, %2, #1 @ without destroying \n\ 90 bne 1b @ the carry flag \n\ 91 adcs %0, %0, %3 \n\ 92 adc %0, %0, #0" 93 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) 94 : "1" (iph), "2" (ihl) 95 : "cc", "memory"); 96 return csum_fold(sum); 97 } 98 99 static inline __wsum 100 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 101 __u8 proto, __wsum sum) 102 { 103 u32 lenprot = len + proto; 104 if (__builtin_constant_p(sum) && sum == 0) { 105 __asm__( 106 "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t" 107 #ifdef __ARMEB__ 108 "adcs %0, %0, %3 \n\t" 109 #else 110 "adcs %0, %0, %3, ror #8 \n\t" 111 #endif 112 "adc %0, %0, #0" 113 : "=&r" (sum) 114 : "r" (daddr), "r" (saddr), "r" (lenprot) 115 : "cc"); 116 } else { 117 __asm__( 118 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t" 119 "adcs %0, %0, %3 \n\t" 120 #ifdef __ARMEB__ 121 "adcs %0, %0, %4 \n\t" 122 #else 123 "adcs %0, %0, %4, ror #8 \n\t" 124 #endif 125 "adc %0, %0, #0" 126 : "=&r"(sum) 127 : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot) 128 : "cc"); 129 } 130 return sum; 131 } 132 /* 133 * computes the checksum of the TCP/UDP pseudo-header 134 * returns a 16-bit checksum, already complemented 135 */ 136 static inline __sum16 137 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 138 __u8 proto, __wsum sum) 139 { 140 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 141 } 142 143 144 /* 145 * this routine is used for miscellaneous IP-like checksums, mainly 146 * in icmp.c 147 */ 148 static inline __sum16 149 ip_compute_csum(const void *buff, int len) 150 { 151 return csum_fold(csum_partial(buff, len, 0)); 152 } 153 154 #define _HAVE_ARCH_IPV6_CSUM 155 extern __wsum 156 __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, 157 __be32 proto, __wsum sum); 158 159 static inline __sum16 160 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, 161 __u32 len, __u8 proto, __wsum sum) 162 { 163 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), 164 htonl(proto), sum)); 165 } 166 #endif 167