1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle 7 * Copyright (C) 1999 Silicon Graphics, Inc. 8 * Copyright (C) 2001 Thiemo Seufer. 9 * Copyright (C) 2002 Maciej W. Rozycki 10 * Copyright (C) 2014 Imagination Technologies Ltd. 11 */ 12 #ifndef _ASM_CHECKSUM_H 13 #define _ASM_CHECKSUM_H 14 15 #ifdef CONFIG_GENERIC_CSUM 16 #include <asm-generic/checksum.h> 17 #else 18 19 #include <linux/in6.h> 20 21 #include <linux/uaccess.h> 22 23 /* 24 * computes the checksum of a memory block at buff, length len, 25 * and adds in "sum" (32-bit) 26 * 27 * returns a 32-bit number suitable for feeding into itself 28 * or csum_tcpudp_magic 29 * 30 * this function must be called with even lengths, except 31 * for the last fragment, which may be odd 32 * 33 * it's best to have buff aligned on a 32-bit boundary 34 */ 35 __wsum csum_partial(const void *buff, int len, __wsum sum); 36 37 __wsum __csum_partial_copy_from_user(const void __user *src, void *dst, int len); 38 __wsum __csum_partial_copy_to_user(const void *src, void __user *dst, int len); 39 40 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 41 static inline 42 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len) 43 { 44 might_fault(); 45 if (!access_ok(src, len)) 46 return 0; 47 return __csum_partial_copy_from_user(src, dst, len); 48 } 49 50 /* 51 * Copy and checksum to user 52 */ 53 #define HAVE_CSUM_COPY_USER 54 static inline 55 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len) 56 { 57 might_fault(); 58 if (!access_ok(dst, len)) 59 return 0; 60 return __csum_partial_copy_to_user(src, dst, len); 61 } 62 63 /* 64 * the same as csum_partial, but copies from user space (but on MIPS 65 * we have just one address space, so this is identical to the above) 66 */ 67 #define _HAVE_ARCH_CSUM_AND_COPY 68 __wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len); 69 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) 70 { 71 return __csum_partial_copy_nocheck(src, dst, len); 72 } 73 74 /* 75 * Fold a partial checksum without adding pseudo headers 76 */ 77 static inline __sum16 csum_fold(__wsum csum) 78 { 79 u32 sum = (__force u32)csum; 80 81 sum += (sum << 16); 82 csum = (__force __wsum)(sum < (__force u32)csum); 83 sum >>= 16; 84 sum += (__force u32)csum; 85 86 return (__force __sum16)~sum; 87 } 88 #define csum_fold csum_fold 89 90 /* 91 * This is a version of ip_compute_csum() optimized for IP headers, 92 * which always checksum on 4 octet boundaries. 93 * 94 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 95 * Arnt Gulbrandsen. 96 */ 97 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 98 { 99 const unsigned int *word = iph; 100 const unsigned int *stop = word + ihl; 101 unsigned int csum; 102 int carry; 103 104 csum = word[0]; 105 csum += word[1]; 106 carry = (csum < word[1]); 107 csum += carry; 108 109 csum += word[2]; 110 carry = (csum < word[2]); 111 csum += carry; 112 113 csum += word[3]; 114 carry = (csum < word[3]); 115 csum += carry; 116 117 word += 4; 118 do { 119 csum += *word; 120 carry = (csum < *word); 121 csum += carry; 122 word++; 123 } while (word != stop); 124 125 return csum_fold(csum); 126 } 127 #define ip_fast_csum ip_fast_csum 128 129 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 130 __u32 len, __u8 proto, 131 __wsum isum) 132 { 133 const unsigned int sh32 = IS_ENABLED(CONFIG_64BIT) ? 32 : 0; 134 unsigned long sum = (__force unsigned long)daddr; 135 unsigned long tmp; 136 __u32 osum; 137 138 tmp = (__force unsigned long)saddr; 139 sum += tmp; 140 141 if (IS_ENABLED(CONFIG_32BIT)) 142 sum += sum < tmp; 143 144 /* 145 * We know PROTO + LEN has the sign bit clear, so cast to a signed 146 * type to avoid an extraneous zero-extension where TMP is 64-bit. 147 */ 148 tmp = (__s32)(proto + len); 149 tmp <<= IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? 8 : 0; 150 sum += tmp; 151 if (IS_ENABLED(CONFIG_32BIT)) 152 sum += sum < tmp; 153 154 tmp = (__force unsigned long)isum; 155 sum += tmp; 156 157 if (IS_ENABLED(CONFIG_32BIT)) { 158 sum += sum < tmp; 159 osum = sum; 160 } else if (IS_ENABLED(CONFIG_64BIT)) { 161 tmp = sum << sh32; 162 sum += tmp; 163 osum = sum < tmp; 164 osum += sum >> sh32; 165 } else { 166 BUILD_BUG(); 167 } 168 169 return (__force __wsum)osum; 170 } 171 #define csum_tcpudp_nofold csum_tcpudp_nofold 172 173 /* 174 * this routine is used for miscellaneous IP-like checksums, mainly 175 * in icmp.c 176 */ 177 static inline __sum16 ip_compute_csum(const void *buff, int len) 178 { 179 return csum_fold(csum_partial(buff, len, 0)); 180 } 181 182 #define _HAVE_ARCH_IPV6_CSUM 183 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 184 const struct in6_addr *daddr, 185 __u32 len, __u8 proto, 186 __wsum sum) 187 { 188 __wsum tmp; 189 190 __asm__( 191 " .set push # csum_ipv6_magic\n" 192 " .set noreorder \n" 193 " .set noat \n" 194 " addu %0, %5 # proto (long in network byte order)\n" 195 " sltu $1, %0, %5 \n" 196 " addu %0, $1 \n" 197 198 " addu %0, %6 # csum\n" 199 " sltu $1, %0, %6 \n" 200 " lw %1, 0(%2) # four words source address\n" 201 " addu %0, $1 \n" 202 " addu %0, %1 \n" 203 " sltu $1, %0, %1 \n" 204 205 " lw %1, 4(%2) \n" 206 " addu %0, $1 \n" 207 " addu %0, %1 \n" 208 " sltu $1, %0, %1 \n" 209 210 " lw %1, 8(%2) \n" 211 " addu %0, $1 \n" 212 " addu %0, %1 \n" 213 " sltu $1, %0, %1 \n" 214 215 " lw %1, 12(%2) \n" 216 " addu %0, $1 \n" 217 " addu %0, %1 \n" 218 " sltu $1, %0, %1 \n" 219 220 " lw %1, 0(%3) \n" 221 " addu %0, $1 \n" 222 " addu %0, %1 \n" 223 " sltu $1, %0, %1 \n" 224 225 " lw %1, 4(%3) \n" 226 " addu %0, $1 \n" 227 " addu %0, %1 \n" 228 " sltu $1, %0, %1 \n" 229 230 " lw %1, 8(%3) \n" 231 " addu %0, $1 \n" 232 " addu %0, %1 \n" 233 " sltu $1, %0, %1 \n" 234 235 " lw %1, 12(%3) \n" 236 " addu %0, $1 \n" 237 " addu %0, %1 \n" 238 " sltu $1, %0, %1 \n" 239 240 " addu %0, $1 # Add final carry\n" 241 " .set pop" 242 : "=&r" (sum), "=&r" (tmp) 243 : "r" (saddr), "r" (daddr), 244 "0" (htonl(len)), "r" (htonl(proto)), "r" (sum)); 245 246 return csum_fold(sum); 247 } 248 249 #include <asm-generic/checksum.h> 250 #endif /* CONFIG_GENERIC_CSUM */ 251 252 #endif /* _ASM_CHECKSUM_H */ 253