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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 | // SPDX-License-Identifier: GPL-2.0-or-later /* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * IP/TCP/UDP checksumming routines * * Authors: Jorge Cwik, <jorge@laser.satlink.net> * Arnt Gulbrandsen, <agulbra@nvg.unit.no> * Tom May, <ftom@netcom.com> * Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de> * Lots of code moved from tcp.c and ip.c; see those files * for more names. * * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: * Fixed some nasty bugs, causing some horrible crashes. * A: At some points, the sum (%0) was used as * length-counter instead of the length counter * (%1). Thanks to Roman Hodek for pointing this out. * B: GCC seems to mess up if one uses too many * data-registers to hold input values and one tries to * specify d0 and d1 as scratch registers. Letting gcc * choose these registers itself solves the problem. * * 1998/8/31 Andreas Schwab: * Zero out rest of buffer on exception in * csum_partial_copy_from_user. */ #include <linux/module.h> #include <net/checksum.h> /* * computes a partial checksum, e.g. for TCP/UDP fragments */ __wsum csum_partial(const void *buff, int len, __wsum sum) { unsigned long tmp1, tmp2; /* * Experiments with ethernet and slip connections show that buff * is aligned on either a 2-byte or 4-byte boundary. */ __asm__("movel %2,%3\n\t" "btst #1,%3\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "addw %2@+,%0\n\t" /* add first word to sum */ "clrl %3\n\t" "addxl %3,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%3\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "dbra %1,1b\n\t" "clrl %4\n\t" "addxl %4,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %3,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%3\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%3\n\t" "subqw #1,%3\n" "3:\t" /* loop for rest longs */ "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "dbra %3,3b\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %4\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movew %2@+,%4\n\t" /* have rest >= 2: get word */ "swap %4\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "moveb %2@,%4\n\t" /* have odd rest: get byte */ "lslw #8,%4\n\t" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %4,%0\n\t" /* now add rest long to sum */ "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (buff), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (buff) ); return(sum); } EXPORT_SYMBOL(csum_partial); /* * copy from user space while checksumming, with exception handling. */ __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len) { /* * GCC doesn't like more than 10 operands for the asm * statements so we have to use tmp2 for the error * code. */ unsigned long tmp1, tmp2; __wsum sum = ~0U; __asm__("movel %2,%4\n\t" "btst #1,%4\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\n" "10:\t" "movesw %2@+,%4\n\t" /* add first word to sum */ "addw %4,%0\n\t" "movew %4,%3@+\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%4\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\n" "11:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "12:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "13:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "14:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "15:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "16:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "17:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "18:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %1,1b\n\t" "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %4,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%4\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "3:\n" /* loop for rest longs */ "19:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %4,3b\n\t" "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %5\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "20:\t" "movesw %2@+,%5\n\t" /* have rest >= 2: get word */ "movew %5,%3@+\n\t" "swap %5\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\n" "21:\t" "movesb %2@,%5\n\t" /* have odd rest: get byte */ "moveb %5,%3@+\n\t" "lslw #8,%5\n\t" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %5,%0\n\t" /* now add rest long to sum */ "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "7:\t" ".section .fixup,\"ax\"\n" ".even\n" /* If any exception occurs, return 0 */ "90:\t" "clrl %0\n" "jra 7b\n" ".previous\n" ".section __ex_table,\"a\"\n" ".long 10b,90b\n" ".long 11b,90b\n" ".long 12b,90b\n" ".long 13b,90b\n" ".long 14b,90b\n" ".long 15b,90b\n" ".long 16b,90b\n" ".long 17b,90b\n" ".long 18b,90b\n" ".long 19b,90b\n" ".long 20b,90b\n" ".long 21b,90b\n" ".previous" : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), "=&d" (tmp1), "=d" (tmp2) : "0" (sum), "1" (len), "2" (src), "3" (dst) ); return sum; } /* * copy from kernel space while checksumming, otherwise like csum_partial */ __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) { unsigned long tmp1, tmp2; __wsum sum = 0; __asm__("movel %2,%4\n\t" "btst #1,%4\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "movew %2@+,%4\n\t" /* add first word to sum */ "addw %4,%0\n\t" "movew %4,%3@+\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%4\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %1,1b\n\t" "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %4,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%4\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "3:\t" /* loop for rest longs */ "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %4,3b\n\t" "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %5\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movew %2@+,%5\n\t" /* have rest >= 2: get word */ "movew %5,%3@+\n\t" "swap %5\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "moveb %2@,%5\n\t" /* have odd rest: get byte */ "moveb %5,%3@+\n\t" "lslw #8,%5\n" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %5,%0\n\t" /* now add rest long to sum */ "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (src), "3" (dst) ); return(sum); } EXPORT_SYMBOL(csum_partial_copy_nocheck); |