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 */ 11 #ifndef _ASM_CHECKSUM_H 12 #define _ASM_CHECKSUM_H 13 14 #include <linux/in6.h> 15 16 #include <asm/uaccess.h> 17 18 /* 19 * computes the checksum of a memory block at buff, length len, 20 * and adds in "sum" (32-bit) 21 * 22 * returns a 32-bit number suitable for feeding into itself 23 * or csum_tcpudp_magic 24 * 25 * this function must be called with even lengths, except 26 * for the last fragment, which may be odd 27 * 28 * it's best to have buff aligned on a 32-bit boundary 29 */ 30 __wsum csum_partial(const void *buff, int len, __wsum sum); 31 32 __wsum __csum_partial_copy_user(const void *src, void *dst, 33 int len, __wsum sum, int *err_ptr); 34 35 /* 36 * this is a new version of the above that records errors it finds in *errp, 37 * but continues and zeros the rest of the buffer. 38 */ 39 static inline 40 __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, 41 __wsum sum, int *err_ptr) 42 { 43 might_sleep(); 44 return __csum_partial_copy_user((__force void *)src, dst, 45 len, sum, err_ptr); 46 } 47 48 /* 49 * Copy and checksum to user 50 */ 51 #define HAVE_CSUM_COPY_USER 52 static inline 53 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len, 54 __wsum sum, int *err_ptr) 55 { 56 might_sleep(); 57 if (access_ok(VERIFY_WRITE, dst, len)) 58 return __csum_partial_copy_user(src, (__force void *)dst, 59 len, sum, err_ptr); 60 if (len) 61 *err_ptr = -EFAULT; 62 63 return (__force __wsum)-1; /* invalid checksum */ 64 } 65 66 /* 67 * the same as csum_partial, but copies from user space (but on MIPS 68 * we have just one address space, so this is identical to the above) 69 */ 70 __wsum csum_partial_copy_nocheck(const void *src, void *dst, 71 int len, __wsum sum); 72 73 /* 74 * Fold a partial checksum without adding pseudo headers 75 */ 76 static inline __sum16 csum_fold(__wsum sum) 77 { 78 __asm__( 79 " .set push # csum_fold\n" 80 " .set noat \n" 81 " sll $1, %0, 16 \n" 82 " addu %0, $1 \n" 83 " sltu $1, %0, $1 \n" 84 " srl %0, %0, 16 \n" 85 " addu %0, $1 \n" 86 " xori %0, 0xffff \n" 87 " .set pop" 88 : "=r" (sum) 89 : "0" (sum)); 90 91 return (__force __sum16)sum; 92 } 93 94 /* 95 * This is a version of ip_compute_csum() optimized for IP headers, 96 * which always checksum on 4 octet boundaries. 97 * 98 * By Jorge Cwik <jorge (at) laser.satlink.net>, adapted for linux by 99 * Arnt Gulbrandsen. 100 */ 101 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 102 { 103 const unsigned int *word = iph; 104 const unsigned int *stop = word + ihl; 105 unsigned int csum; 106 int carry; 107 108 csum = word[0]; 109 csum += word[1]; 110 carry = (csum < word[1]); 111 csum += carry; 112 113 csum += word[2]; 114 carry = (csum < word[2]); 115 csum += carry; 116 117 csum += word[3]; 118 carry = (csum < word[3]); 119 csum += carry; 120 121 word += 4; 122 do { 123 csum += *word; 124 carry = (csum < *word); 125 csum += carry; 126 word++; 127 } while (word != stop); 128 129 return csum_fold(csum); 130 } 131 132 static inline __wsum csum_tcpudp_nofold(__be32 saddr, 133 __be32 daddr, unsigned short len, unsigned short proto, 134 __wsum sum) 135 { 136 __asm__( 137 " .set push # csum_tcpudp_nofold\n" 138 " .set noat \n" 139 #ifdef CONFIG_32BIT 140 " addu %0, %2 \n" 141 " sltu $1, %0, %2 \n" 142 " addu %0, $1 \n" 143 144 " addu %0, %3 \n" 145 " sltu $1, %0, %3 \n" 146 " addu %0, $1 \n" 147 148 " addu %0, %4 \n" 149 " sltu $1, %0, %4 \n" 150 " addu %0, $1 \n" 151 #endif 152 #ifdef CONFIG_64BIT 153 " daddu %0, %2 \n" 154 " daddu %0, %3 \n" 155 " daddu %0, %4 \n" 156 " dsll32 $1, %0, 0 \n" 157 " daddu %0, $1 \n" 158 " dsra32 %0, %0, 0 \n" 159 #endif 160 " .set pop" 161 : "=r" (sum) 162 : "0" ((__force unsigned long)daddr), 163 "r" ((__force unsigned long)saddr), 164 #ifdef __MIPSEL__ 165 "r" ((proto + len) << 8), 166 #else 167 "r" (proto + len), 168 #endif 169 "r" ((__force unsigned long)sum)); 170 171 return sum; 172 } 173 174 /* 175 * computes the checksum of the TCP/UDP pseudo-header 176 * returns a 16-bit checksum, already complemented 177 */ 178 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 179 unsigned short len, 180 unsigned short proto, 181 __wsum sum) 182 { 183 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 184 } 185 186 /* 187 * this routine is used for miscellaneous IP-like checksums, mainly 188 * in icmp.c 189 */ 190 static inline __sum16 ip_compute_csum(const void *buff, int len) 191 { 192 return csum_fold(csum_partial(buff, len, 0)); 193 } 194 195 #define _HAVE_ARCH_IPV6_CSUM 196 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 197 const struct in6_addr *daddr, 198 __u32 len, unsigned short proto, 199 __wsum sum) 200 { 201 __asm__( 202 " .set push # csum_ipv6_magic\n" 203 " .set noreorder \n" 204 " .set noat \n" 205 " addu %0, %5 # proto (long in network byte order)\n" 206 " sltu $1, %0, %5 \n" 207 " addu %0, $1 \n" 208 209 " addu %0, %6 # csum\n" 210 " sltu $1, %0, %6 \n" 211 " lw %1, 0(%2) # four words source address\n" 212 " addu %0, $1 \n" 213 " addu %0, %1 \n" 214 " sltu $1, %0, %1 \n" 215 216 " lw %1, 4(%2) \n" 217 " addu %0, $1 \n" 218 " addu %0, %1 \n" 219 " sltu $1, %0, %1 \n" 220 221 " lw %1, 8(%2) \n" 222 " addu %0, $1 \n" 223 " addu %0, %1 \n" 224 " sltu $1, %0, %1 \n" 225 226 " lw %1, 12(%2) \n" 227 " addu %0, $1 \n" 228 " addu %0, %1 \n" 229 " sltu $1, %0, %1 \n" 230 231 " lw %1, 0(%3) \n" 232 " addu %0, $1 \n" 233 " addu %0, %1 \n" 234 " sltu $1, %0, %1 \n" 235 236 " lw %1, 4(%3) \n" 237 " addu %0, $1 \n" 238 " addu %0, %1 \n" 239 " sltu $1, %0, %1 \n" 240 241 " lw %1, 8(%3) \n" 242 " addu %0, $1 \n" 243 " addu %0, %1 \n" 244 " sltu $1, %0, %1 \n" 245 246 " lw %1, 12(%3) \n" 247 " addu %0, $1 \n" 248 " addu %0, %1 \n" 249 " sltu $1, %0, %1 \n" 250 251 " addu %0, $1 # Add final carry\n" 252 " .set pop" 253 : "=r" (sum), "=r" (proto) 254 : "r" (saddr), "r" (daddr), 255 "0" (htonl(len)), "1" (htonl(proto)), "r" (sum)); 256 257 return csum_fold(sum); 258 } 259 260 #endif /* _ASM_CHECKSUM_H */ 261
