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 sum) 132 { 133 unsigned long tmp = (__force unsigned long)sum; 134 135 __asm__( 136 " .set push # csum_tcpudp_nofold\n" 137 " .set noat \n" 138 #ifdef CONFIG_32BIT 139 " addu %0, %2 \n" 140 " sltu $1, %0, %2 \n" 141 " addu %0, $1 \n" 142 143 " addu %0, %3 \n" 144 " sltu $1, %0, %3 \n" 145 " addu %0, $1 \n" 146 147 " addu %0, %4 \n" 148 " sltu $1, %0, %4 \n" 149 " addu %0, $1 \n" 150 #endif 151 #ifdef CONFIG_64BIT 152 " daddu %0, %2 \n" 153 " daddu %0, %3 \n" 154 " daddu %0, %4 \n" 155 " dsll32 $1, %0, 0 \n" 156 " daddu %0, $1 \n" 157 " sltu $1, %0, $1 \n" 158 " dsra32 %0, %0, 0 \n" 159 " addu %0, $1 \n" 160 #endif 161 " .set pop" 162 : "=r" (tmp) 163 : "0" ((__force unsigned long)daddr), 164 "r" ((__force unsigned long)saddr), 165 #ifdef __MIPSEL__ 166 "r" ((proto + len) << 8), 167 #else 168 "r" (proto + len), 169 #endif 170 "r" ((__force unsigned long)sum)); 171 172 return (__force __wsum)tmp; 173 } 174 #define csum_tcpudp_nofold csum_tcpudp_nofold 175 176 /* 177 * this routine is used for miscellaneous IP-like checksums, mainly 178 * in icmp.c 179 */ 180 static inline __sum16 ip_compute_csum(const void *buff, int len) 181 { 182 return csum_fold(csum_partial(buff, len, 0)); 183 } 184 185 #define _HAVE_ARCH_IPV6_CSUM 186 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 187 const struct in6_addr *daddr, 188 __u32 len, __u8 proto, 189 __wsum sum) 190 { 191 __wsum tmp; 192 193 __asm__( 194 " .set push # csum_ipv6_magic\n" 195 " .set noreorder \n" 196 " .set noat \n" 197 " addu %0, %5 # proto (long in network byte order)\n" 198 " sltu $1, %0, %5 \n" 199 " addu %0, $1 \n" 200 201 " addu %0, %6 # csum\n" 202 " sltu $1, %0, %6 \n" 203 " lw %1, 0(%2) # four words source address\n" 204 " addu %0, $1 \n" 205 " addu %0, %1 \n" 206 " sltu $1, %0, %1 \n" 207 208 " lw %1, 4(%2) \n" 209 " addu %0, $1 \n" 210 " addu %0, %1 \n" 211 " sltu $1, %0, %1 \n" 212 213 " lw %1, 8(%2) \n" 214 " addu %0, $1 \n" 215 " addu %0, %1 \n" 216 " sltu $1, %0, %1 \n" 217 218 " lw %1, 12(%2) \n" 219 " addu %0, $1 \n" 220 " addu %0, %1 \n" 221 " sltu $1, %0, %1 \n" 222 223 " lw %1, 0(%3) \n" 224 " addu %0, $1 \n" 225 " addu %0, %1 \n" 226 " sltu $1, %0, %1 \n" 227 228 " lw %1, 4(%3) \n" 229 " addu %0, $1 \n" 230 " addu %0, %1 \n" 231 " sltu $1, %0, %1 \n" 232 233 " lw %1, 8(%3) \n" 234 " addu %0, $1 \n" 235 " addu %0, %1 \n" 236 " sltu $1, %0, %1 \n" 237 238 " lw %1, 12(%3) \n" 239 " addu %0, $1 \n" 240 " addu %0, %1 \n" 241 " sltu $1, %0, %1 \n" 242 243 " addu %0, $1 # Add final carry\n" 244 " .set pop" 245 : "=&r" (sum), "=&r" (tmp) 246 : "r" (saddr), "r" (daddr), 247 "0" (htonl(len)), "r" (htonl(proto)), "r" (sum)); 248 249 return csum_fold(sum); 250 } 251 252 #include <asm-generic/checksum.h> 253 #endif /* CONFIG_GENERIC_CSUM */ 254 255 #endif /* _ASM_CHECKSUM_H */ 256