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 #include <linux/in6.h> 16 17 #include <asm/uaccess.h> 18 19 /* 20 * computes the checksum of a memory block at buff, length len, 21 * and adds in "sum" (32-bit) 22 * 23 * returns a 32-bit number suitable for feeding into itself 24 * or csum_tcpudp_magic 25 * 26 * this function must be called with even lengths, except 27 * for the last fragment, which may be odd 28 * 29 * it's best to have buff aligned on a 32-bit boundary 30 */ 31 __wsum csum_partial(const void *buff, int len, __wsum sum); 32 33 __wsum __csum_partial_copy_kernel(const void *src, void *dst, 34 int len, __wsum sum, int *err_ptr); 35 36 __wsum __csum_partial_copy_from_user(const void *src, void *dst, 37 int len, __wsum sum, int *err_ptr); 38 __wsum __csum_partial_copy_to_user(const void *src, void *dst, 39 int len, __wsum sum, int *err_ptr); 40 /* 41 * this is a new version of the above that records errors it finds in *errp, 42 * but continues and zeros the rest of the buffer. 43 */ 44 static inline 45 __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, 46 __wsum sum, int *err_ptr) 47 { 48 might_fault(); 49 if (segment_eq(get_fs(), get_ds())) 50 return __csum_partial_copy_kernel((__force void *)src, dst, 51 len, sum, err_ptr); 52 else 53 return __csum_partial_copy_from_user((__force void *)src, dst, 54 len, sum, err_ptr); 55 } 56 57 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 58 static inline 59 __wsum csum_and_copy_from_user(const void __user *src, void *dst, 60 int len, __wsum sum, int *err_ptr) 61 { 62 if (access_ok(VERIFY_READ, src, len)) 63 return csum_partial_copy_from_user(src, dst, len, sum, 64 err_ptr); 65 if (len) 66 *err_ptr = -EFAULT; 67 68 return sum; 69 } 70 71 /* 72 * Copy and checksum to user 73 */ 74 #define HAVE_CSUM_COPY_USER 75 static inline 76 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len, 77 __wsum sum, int *err_ptr) 78 { 79 might_fault(); 80 if (access_ok(VERIFY_WRITE, dst, len)) { 81 if (segment_eq(get_fs(), get_ds())) 82 return __csum_partial_copy_kernel(src, 83 (__force void *)dst, 84 len, sum, err_ptr); 85 else 86 return __csum_partial_copy_to_user(src, 87 (__force void *)dst, 88 len, sum, err_ptr); 89 } 90 if (len) 91 *err_ptr = -EFAULT; 92 93 return (__force __wsum)-1; /* invalid checksum */ 94 } 95 96 /* 97 * the same as csum_partial, but copies from user space (but on MIPS 98 * we have just one address space, so this is identical to the above) 99 */ 100 __wsum csum_partial_copy_nocheck(const void *src, void *dst, 101 int len, __wsum sum); 102 103 /* 104 * Fold a partial checksum without adding pseudo headers 105 */ 106 static inline __sum16 csum_fold(__wsum sum) 107 { 108 __asm__( 109 " .set push # csum_fold\n" 110 " .set noat \n" 111 " sll $1, %0, 16 \n" 112 " addu %0, $1 \n" 113 " sltu $1, %0, $1 \n" 114 " srl %0, %0, 16 \n" 115 " addu %0, $1 \n" 116 " xori %0, 0xffff \n" 117 " .set pop" 118 : "=r" (sum) 119 : "0" (sum)); 120 121 return (__force __sum16)sum; 122 } 123 124 /* 125 * This is a version of ip_compute_csum() optimized for IP headers, 126 * which always checksum on 4 octet boundaries. 127 * 128 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 129 * Arnt Gulbrandsen. 130 */ 131 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 132 { 133 const unsigned int *word = iph; 134 const unsigned int *stop = word + ihl; 135 unsigned int csum; 136 int carry; 137 138 csum = word[0]; 139 csum += word[1]; 140 carry = (csum < word[1]); 141 csum += carry; 142 143 csum += word[2]; 144 carry = (csum < word[2]); 145 csum += carry; 146 147 csum += word[3]; 148 carry = (csum < word[3]); 149 csum += carry; 150 151 word += 4; 152 do { 153 csum += *word; 154 carry = (csum < *word); 155 csum += carry; 156 word++; 157 } while (word != stop); 158 159 return csum_fold(csum); 160 } 161 162 static inline __wsum csum_tcpudp_nofold(__be32 saddr, 163 __be32 daddr, unsigned short len, unsigned short proto, 164 __wsum sum) 165 { 166 __asm__( 167 " .set push # csum_tcpudp_nofold\n" 168 " .set noat \n" 169 #ifdef CONFIG_32BIT 170 " addu %0, %2 \n" 171 " sltu $1, %0, %2 \n" 172 " addu %0, $1 \n" 173 174 " addu %0, %3 \n" 175 " sltu $1, %0, %3 \n" 176 " addu %0, $1 \n" 177 178 " addu %0, %4 \n" 179 " sltu $1, %0, %4 \n" 180 " addu %0, $1 \n" 181 #endif 182 #ifdef CONFIG_64BIT 183 " daddu %0, %2 \n" 184 " daddu %0, %3 \n" 185 " daddu %0, %4 \n" 186 " dsll32 $1, %0, 0 \n" 187 " daddu %0, $1 \n" 188 " dsra32 %0, %0, 0 \n" 189 #endif 190 " .set pop" 191 : "=r" (sum) 192 : "0" ((__force unsigned long)daddr), 193 "r" ((__force unsigned long)saddr), 194 #ifdef __MIPSEL__ 195 "r" ((proto + len) << 8), 196 #else 197 "r" (proto + len), 198 #endif 199 "r" ((__force unsigned long)sum)); 200 201 return sum; 202 } 203 204 /* 205 * computes the checksum of the TCP/UDP pseudo-header 206 * returns a 16-bit checksum, already complemented 207 */ 208 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 209 unsigned short len, 210 unsigned short proto, 211 __wsum sum) 212 { 213 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 214 } 215 216 /* 217 * this routine is used for miscellaneous IP-like checksums, mainly 218 * in icmp.c 219 */ 220 static inline __sum16 ip_compute_csum(const void *buff, int len) 221 { 222 return csum_fold(csum_partial(buff, len, 0)); 223 } 224 225 #define _HAVE_ARCH_IPV6_CSUM 226 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 227 const struct in6_addr *daddr, 228 __u32 len, unsigned short proto, 229 __wsum sum) 230 { 231 __asm__( 232 " .set push # csum_ipv6_magic\n" 233 " .set noreorder \n" 234 " .set noat \n" 235 " addu %0, %5 # proto (long in network byte order)\n" 236 " sltu $1, %0, %5 \n" 237 " addu %0, $1 \n" 238 239 " addu %0, %6 # csum\n" 240 " sltu $1, %0, %6 \n" 241 " lw %1, 0(%2) # four words source address\n" 242 " addu %0, $1 \n" 243 " addu %0, %1 \n" 244 " sltu $1, %0, %1 \n" 245 246 " lw %1, 4(%2) \n" 247 " addu %0, $1 \n" 248 " addu %0, %1 \n" 249 " sltu $1, %0, %1 \n" 250 251 " lw %1, 8(%2) \n" 252 " addu %0, $1 \n" 253 " addu %0, %1 \n" 254 " sltu $1, %0, %1 \n" 255 256 " lw %1, 12(%2) \n" 257 " addu %0, $1 \n" 258 " addu %0, %1 \n" 259 " sltu $1, %0, %1 \n" 260 261 " lw %1, 0(%3) \n" 262 " addu %0, $1 \n" 263 " addu %0, %1 \n" 264 " sltu $1, %0, %1 \n" 265 266 " lw %1, 4(%3) \n" 267 " addu %0, $1 \n" 268 " addu %0, %1 \n" 269 " sltu $1, %0, %1 \n" 270 271 " lw %1, 8(%3) \n" 272 " addu %0, $1 \n" 273 " addu %0, %1 \n" 274 " sltu $1, %0, %1 \n" 275 276 " lw %1, 12(%3) \n" 277 " addu %0, $1 \n" 278 " addu %0, %1 \n" 279 " sltu $1, %0, %1 \n" 280 281 " addu %0, $1 # Add final carry\n" 282 " .set pop" 283 : "=r" (sum), "=r" (proto) 284 : "r" (saddr), "r" (daddr), 285 "0" (htonl(len)), "1" (htonl(proto)), "r" (sum)); 286 287 return csum_fold(sum); 288 } 289 290 #endif /* _ASM_CHECKSUM_H */ 291