| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id$ |
| 4 | * |
| 5 | * Buffer handling |
| 6 | * |
| 7 | * (c) 2001 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Catacomb. |
| 13 | * |
| 14 | * Catacomb is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * Catacomb is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with Catacomb; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Header files ------------------------------------------------------*/ |
| 31 | |
| 32 | #include <string.h> |
| 33 | |
| 34 | #include "mp.h" |
| 35 | #include "ec.h" |
| 36 | #include "buf.h" |
| 37 | |
| 38 | /*----- Main code ---------------------------------------------------------*/ |
| 39 | |
| 40 | /* --- @buf_init@ --- * |
| 41 | * |
| 42 | * Arguments: @buf *b@ = pointer to a buffer block |
| 43 | * @void *p@ = pointer to a buffer |
| 44 | * @size_t sz@ = size of the buffer |
| 45 | * |
| 46 | * Returns: --- |
| 47 | * |
| 48 | * Use: Initializes the buffer block appropriately. |
| 49 | */ |
| 50 | |
| 51 | void buf_init(buf *b, void *p, size_t sz) |
| 52 | { |
| 53 | b->base = b->p = p; |
| 54 | b->limit = b->p + sz; |
| 55 | b->f = 0; |
| 56 | } |
| 57 | |
| 58 | /* --- @buf_break@ --- * |
| 59 | * |
| 60 | * Arguments: @buf *b@ = pointer to a buffer block |
| 61 | * |
| 62 | * Returns: Some negative value. |
| 63 | * |
| 64 | * Use: Marks a buffer as broken. |
| 65 | */ |
| 66 | |
| 67 | int buf_break(buf *b) { b->f |= BF_BROKEN; return (-1); } |
| 68 | |
| 69 | /* --- @buf_flip@ --- * |
| 70 | * |
| 71 | * Arguments: @buf *b@ = pointer to a buffer block |
| 72 | * |
| 73 | * Returns: --- |
| 74 | * |
| 75 | * Use: Flips a buffer so that if you've just been writing to it, |
| 76 | * you can now read from the bit you've written. |
| 77 | */ |
| 78 | |
| 79 | void buf_flip(buf *b) |
| 80 | { |
| 81 | b->limit = b->p; |
| 82 | b->p = b->base; |
| 83 | } |
| 84 | |
| 85 | /* --- @buf_ensure@ --- * |
| 86 | * |
| 87 | * Arguments: @buf *b@ = pointer to a buffer block |
| 88 | * @size_t sz@ = size of data wanted |
| 89 | * |
| 90 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 91 | * |
| 92 | * Use: Ensures that there are @sz@ bytes still in the buffer. |
| 93 | */ |
| 94 | |
| 95 | int buf_ensure(buf *b, size_t sz) { return (BENSURE(b, sz)); } |
| 96 | |
| 97 | /* --- @buf_get@ --- * |
| 98 | * |
| 99 | * Arguments: @buf *b@ = pointer to a buffer block |
| 100 | * @size_t sz@ = size of the buffer |
| 101 | * |
| 102 | * Returns: Pointer to the place in the buffer. |
| 103 | * |
| 104 | * Use: Reserves a space in the buffer of the requested size, and |
| 105 | * returns its start address. |
| 106 | */ |
| 107 | |
| 108 | void *buf_get(buf *b, size_t sz) |
| 109 | { |
| 110 | void *p; |
| 111 | if (BENSURE(b, sz)) |
| 112 | return (0); |
| 113 | p = BCUR(b); |
| 114 | BSTEP(b, sz); |
| 115 | return (p); |
| 116 | } |
| 117 | |
| 118 | /* --- @buf_put@ --- * |
| 119 | * |
| 120 | * Arguments: @buf *b@ = pointer to a buffer block |
| 121 | * @const void *p@ = pointer to a buffer |
| 122 | * @size_t sz@ = size of the buffer |
| 123 | * |
| 124 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 125 | * |
| 126 | * Use: Fetches data from some place and puts it in the buffer |
| 127 | */ |
| 128 | |
| 129 | int buf_put(buf *b, const void *p, size_t sz) |
| 130 | { |
| 131 | if (BENSURE(b, sz)) |
| 132 | return (-1); |
| 133 | memcpy(BCUR(b), p, sz); |
| 134 | BSTEP(b, sz); |
| 135 | return (0); |
| 136 | } |
| 137 | |
| 138 | /* --- @buf_getbyte@ --- * |
| 139 | * |
| 140 | * Arguments: @buf *b@ = pointer to a buffer block |
| 141 | * |
| 142 | * Returns: A byte, or less than zero if there wasn't a byte there. |
| 143 | * |
| 144 | * Use: Gets a single byte from a buffer. |
| 145 | */ |
| 146 | |
| 147 | int buf_getbyte(buf *b) |
| 148 | { |
| 149 | if (BENSURE(b, 1)) |
| 150 | return (-1); |
| 151 | return (*b->p++); |
| 152 | } |
| 153 | |
| 154 | /* --- @buf_putbyte@ --- * |
| 155 | * |
| 156 | * Arguments: @buf *b@ = pointer to a buffer block |
| 157 | * @int ch@ = byte to write |
| 158 | * |
| 159 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
| 160 | * |
| 161 | * Use: Puts a single byte in a buffer. |
| 162 | */ |
| 163 | |
| 164 | int buf_putbyte(buf *b, int ch) |
| 165 | { |
| 166 | if (BENSURE(b, 1)) |
| 167 | return (-1); |
| 168 | *b->p++ = ch; |
| 169 | return (0); |
| 170 | } |
| 171 | |
| 172 | /* --- @buf_getu16@ --- * |
| 173 | * |
| 174 | * Arguments: @buf *b@ = pointer to a buffer block |
| 175 | * @uint16 *w@ = where to put the word |
| 176 | * |
| 177 | * Returns: Zero if OK, or nonzero if there wasn't a word there. |
| 178 | * |
| 179 | * Use: Gets a 16-bit word from a buffer. |
| 180 | */ |
| 181 | |
| 182 | int buf_getu16(buf *b, uint16 *w) |
| 183 | { |
| 184 | if (BENSURE(b, 2)) |
| 185 | return (-1); |
| 186 | *w = LOAD16(b->p); |
| 187 | BSTEP(b, 2); |
| 188 | return (0); |
| 189 | } |
| 190 | |
| 191 | /* --- @buf_putu16@ --- * |
| 192 | * |
| 193 | * Arguments: @buf *b@ = pointer to a buffer block |
| 194 | * @uint16 w@ = word to write |
| 195 | * |
| 196 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
| 197 | * |
| 198 | * Use: Puts a 16-but word in a buffer. |
| 199 | */ |
| 200 | |
| 201 | int buf_putu16(buf *b, uint16 w) |
| 202 | { |
| 203 | if (BENSURE(b, 2)) |
| 204 | return (-1); |
| 205 | STORE16(b->p, w); |
| 206 | BSTEP(b, 2); |
| 207 | return (0); |
| 208 | } |
| 209 | |
| 210 | /* --- @buf_getu32@ --- * |
| 211 | * |
| 212 | * Arguments: @buf *b@ = pointer to a buffer block |
| 213 | * @uint32 *w@ = where to put the word |
| 214 | * |
| 215 | * Returns: Zero if OK, or nonzero if there wasn't a word there. |
| 216 | * |
| 217 | * Use: Gets a 32-bit word from a buffer. |
| 218 | */ |
| 219 | |
| 220 | int buf_getu32(buf *b, uint32 *w) |
| 221 | { |
| 222 | if (BENSURE(b, 4)) |
| 223 | return (-1); |
| 224 | *w = LOAD32(b->p); |
| 225 | BSTEP(b, 4); |
| 226 | return (0); |
| 227 | } |
| 228 | |
| 229 | /* --- @buf_putu32@ --- * |
| 230 | * |
| 231 | * Arguments: @buf *b@ = pointer to a buffer block |
| 232 | * @uint32 w@ = word to write |
| 233 | * |
| 234 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
| 235 | * |
| 236 | * Use: Puts a 32-but word in a buffer. |
| 237 | */ |
| 238 | |
| 239 | int buf_putu32(buf *b, uint32 w) |
| 240 | { |
| 241 | if (BENSURE(b, 4)) |
| 242 | return (-1); |
| 243 | STORE32(b->p, w); |
| 244 | BSTEP(b, 4); |
| 245 | return (0); |
| 246 | } |
| 247 | |
| 248 | /* --- @findz@ --- * |
| 249 | * |
| 250 | * Arguments: @buf *b@ = pointer to a buffer block |
| 251 | * @size_t *nn@ = where to put the length |
| 252 | * |
| 253 | * Returns: Zero if OK, nonzero if there wasn't a null byte to be found. |
| 254 | * |
| 255 | * Use: Finds a terminating null byte. |
| 256 | */ |
| 257 | |
| 258 | static int findz(buf *b, size_t *nn) |
| 259 | { |
| 260 | octet *p; |
| 261 | |
| 262 | if ((p = memchr(BCUR(b), 0, BLEN(b))) == 0) { |
| 263 | buf_break(b); |
| 264 | return (-1); |
| 265 | } |
| 266 | *nn = p - BCUR(b); |
| 267 | return (0); |
| 268 | } |
| 269 | |
| 270 | #define DOSUFFIXES(DO) DO(8) DO(16) DO(32) DO(z) |
| 271 | |
| 272 | /* --- @buf_getmem{8,16,32,z} --- * |
| 273 | * |
| 274 | * Arguments: @buf *b@ = pointer to a buffer block |
| 275 | * @size_t *nn@ = where to put the length |
| 276 | * |
| 277 | * Returns: Pointer to the buffer data, or null. |
| 278 | * |
| 279 | * Use: Gets a chunk of memory from a buffer. The number, @16@ or |
| 280 | * @32@, is the width of the length; @z@ means null-terminated. |
| 281 | */ |
| 282 | |
| 283 | void *buf_getmem8(buf *b, size_t *nn) |
| 284 | { |
| 285 | int n; |
| 286 | |
| 287 | if ((n = buf_getbyte(b)) < 0) return (0); |
| 288 | *nn = n; |
| 289 | return (buf_get(b, n)); |
| 290 | } |
| 291 | |
| 292 | void *buf_getmem16(buf *b, size_t *nn) |
| 293 | { |
| 294 | uint16 n; |
| 295 | |
| 296 | if (buf_getu16(b, &n)) return (0); |
| 297 | *nn = n; |
| 298 | return (buf_get(b, n)); |
| 299 | } |
| 300 | |
| 301 | void *buf_getmem32(buf *b, size_t *nn) |
| 302 | { |
| 303 | uint32 n; |
| 304 | |
| 305 | if (buf_getu32(b, &n)) return (0); |
| 306 | *nn = n; |
| 307 | return (buf_get(b, n)); |
| 308 | } |
| 309 | |
| 310 | void *buf_getmemz(buf *b, size_t *nn) |
| 311 | { |
| 312 | if (findz(b, nn)) return (0); |
| 313 | return (buf_get(b, *nn)); |
| 314 | } |
| 315 | |
| 316 | /* --- @buf_putmem{8,16,32,z} --- * |
| 317 | * |
| 318 | * Arguments: @buf *b@ = pointer to a buffer block |
| 319 | * @const void *p@ = pointer to data to write |
| 320 | * @size_t n@ = length to write |
| 321 | * |
| 322 | * Returns: Zero if OK, nonzero if there wasn't enough space. |
| 323 | * |
| 324 | * Use: Writes a chunk of data to a buffer. The number, @16@ or |
| 325 | * @32@, is the width of the length; @z@ means null-terminated. |
| 326 | */ |
| 327 | |
| 328 | int buf_putmem8(buf *b, const void *p, size_t n) |
| 329 | { |
| 330 | assert(n <= 0xfful); |
| 331 | if (buf_putbyte(b, n) || buf_put(b, p, n)) |
| 332 | return (-1); |
| 333 | return (0); |
| 334 | } |
| 335 | |
| 336 | int buf_putmem16(buf *b, const void *p, size_t n) |
| 337 | { |
| 338 | assert(n <= 0xfffful); |
| 339 | if (buf_putu16(b, n) || buf_put(b, p, n)) |
| 340 | return (-1); |
| 341 | return (0); |
| 342 | } |
| 343 | |
| 344 | int buf_putmem32(buf *b, const void *p, size_t n) |
| 345 | { |
| 346 | assert(n <= 0xfffffffful); |
| 347 | if (buf_putu32(b, n) || buf_put(b, p, n)) |
| 348 | return (-1); |
| 349 | return (0); |
| 350 | } |
| 351 | |
| 352 | int buf_putmemz(buf *b, const void *p, size_t n) |
| 353 | { |
| 354 | octet *q; |
| 355 | |
| 356 | assert(!memchr(p, 0, n)); |
| 357 | if ((q = buf_get(b, n + 1)) == 0) |
| 358 | return (-1); |
| 359 | memcpy(q, p, n); |
| 360 | q[n] = 0; |
| 361 | return (0); |
| 362 | } |
| 363 | |
| 364 | /* --- @buf_getbuf{8,16,32,z}@ --- * |
| 365 | * |
| 366 | * Arguments: @buf *b@ = pointer to a buffer block |
| 367 | * @buf *bb@ = where to put the result |
| 368 | * |
| 369 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 370 | * |
| 371 | * Use: Gets a block of data from a buffer, and writes its bounds to |
| 372 | * another buffer. The number, @16@ or @32@, is the width of |
| 373 | * the length; @z@ means null-terminated. |
| 374 | */ |
| 375 | |
| 376 | #define GETBUF(suff) int buf_getbuf##suff(buf *b, buf *bb) \ |
| 377 | { \ |
| 378 | void *p; \ |
| 379 | size_t n; \ |
| 380 | \ |
| 381 | if ((p = buf_getmem##suff(b, &n)) == 0) \ |
| 382 | return (-1); \ |
| 383 | buf_init(bb, p, n); \ |
| 384 | return (0); \ |
| 385 | } |
| 386 | DOSUFFIXES(GETBUF) |
| 387 | |
| 388 | /* --- @buf_putbuf{8,16,32,z}@ --- * |
| 389 | * |
| 390 | * Arguments: @buf *b@ = pointer to a buffer block |
| 391 | * @buf *bb@ = buffer to write |
| 392 | * |
| 393 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 394 | * |
| 395 | * Use: Puts the contents of a buffer to a buffer. The number, @16@ |
| 396 | * or @32@, is the width of the length; @z@ means null- |
| 397 | * terminated. |
| 398 | */ |
| 399 | |
| 400 | #define PUTBUF(suff) int buf_putbuf##suff(buf *b, buf *bb) \ |
| 401 | { return (buf_putmem##suff(b, BBASE(bb), BLEN(bb))); } |
| 402 | DOSUFFIXES(PUTBUF) |
| 403 | |
| 404 | /* --- @buf_getstr{8,16,32,z}@ --- * |
| 405 | * |
| 406 | * Arguments: @buf *b@ = pointer to a buffer block |
| 407 | * @dstr *d@ = where to put the result |
| 408 | * |
| 409 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 410 | * |
| 411 | * Use: Gets a block of data from a buffer, and writes its contents |
| 412 | * to a string. The number, @16@ or @32@, is the width of the |
| 413 | * length; @z@ means null-terminated. |
| 414 | */ |
| 415 | |
| 416 | #define GETSTR(suff) int buf_getstr##suff(buf *b, dstr *d) \ |
| 417 | { \ |
| 418 | void *p; \ |
| 419 | size_t n; \ |
| 420 | \ |
| 421 | if ((p = buf_getmem##suff(b, &n)) == 0) \ |
| 422 | return (-1); \ |
| 423 | DPUTM(d, p, n); \ |
| 424 | return (0); \ |
| 425 | } |
| 426 | DOSUFFIXES(GETSTR) |
| 427 | |
| 428 | /* --- @buf_putstr{8,16,32,z}@ --- * |
| 429 | * |
| 430 | * Arguments: @buf *b@ = pointer to a buffer block |
| 431 | * @dstr *d@ = string to write |
| 432 | * |
| 433 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 434 | * |
| 435 | * Use: Puts a string to a buffer, and writes its bounds to |
| 436 | * another buffer. The number, @16@ or @32@, is the width of |
| 437 | * the length; @z@ means null-terminated. |
| 438 | */ |
| 439 | |
| 440 | #define PUTSTR(suff) int buf_putstr##suff(buf *b, dstr *d) \ |
| 441 | { return (buf_putmem##suff(b, d->buf, d->len)); } |
| 442 | DOSUFFIXES(PUTSTR) |
| 443 | |
| 444 | /* --- @buf_getmp@ --- * |
| 445 | * |
| 446 | * Arguments: @buf *b@ = pointer to a buffer block |
| 447 | * |
| 448 | * Returns: A multiprecision integer, or null if there wasn't one there. |
| 449 | * |
| 450 | * Use: Gets a multiprecision integer from a buffer. |
| 451 | */ |
| 452 | |
| 453 | mp *buf_getmp(buf *b) |
| 454 | { |
| 455 | uint16 sz; |
| 456 | size_t n; |
| 457 | mp *m; |
| 458 | if (buf_getu16(b, &sz) || buf_ensure(b, sz)) |
| 459 | return (0); |
| 460 | m = mp_loadb(MP_NEW, BCUR(b), sz); |
| 461 | n = mp_octets(m); |
| 462 | if (n != sz && n != 0 && sz != 1) { |
| 463 | mp_drop(m); |
| 464 | return (0); |
| 465 | } |
| 466 | BSTEP(b, sz); |
| 467 | return (m); |
| 468 | } |
| 469 | |
| 470 | /* --- @buf_putmp@ --- * |
| 471 | * |
| 472 | * Arguments: @buf *b@ = pointer to a buffer block |
| 473 | * @mp *m@ = a multiprecision integer |
| 474 | * |
| 475 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 476 | * |
| 477 | * Use: Puts a multiprecision integer to a buffer. |
| 478 | */ |
| 479 | |
| 480 | int buf_putmp(buf *b, mp *m) |
| 481 | { |
| 482 | size_t sz = mp_octets(m); |
| 483 | assert(sz < MASK16); |
| 484 | if (!sz) sz = 1; |
| 485 | if (buf_putu16(b, sz) || buf_ensure(b, sz)) |
| 486 | return (-1); |
| 487 | mp_storeb(m, BCUR(b), sz); |
| 488 | BSTEP(b, sz); |
| 489 | return (0); |
| 490 | } |
| 491 | |
| 492 | /* --- @buf_getec@ --- * |
| 493 | * |
| 494 | * Arguments: @buf *b@ = pointer to a buffer block |
| 495 | * @ec *p@ = where to put the point |
| 496 | * |
| 497 | * Returns: Zero if it worked, nonzero if it failed. |
| 498 | * |
| 499 | * Use: Gets a multiprecision integer from a buffer. The point must |
| 500 | * be initialized. |
| 501 | */ |
| 502 | |
| 503 | int buf_getec(buf *b, ec *p) |
| 504 | { |
| 505 | mp *x = 0, *y = 0; |
| 506 | uint16 n; |
| 507 | if (buf_ensure(b, 2)) return (-1); |
| 508 | n = LOAD16(BCUR(b)); if (!n) { BSTEP(b, 2); EC_SETINF(p); return (0); } |
| 509 | if ((x = buf_getmp(b)) == 0 || (y = buf_getmp(b)) == 0) { |
| 510 | mp_drop(x); mp_drop(y); return (-1); |
| 511 | } |
| 512 | EC_DESTROY(p); p->x = x; p->y = y; p->z = 0; |
| 513 | return (0); |
| 514 | } |
| 515 | |
| 516 | /* --- @buf_putec@ --- * |
| 517 | * |
| 518 | * Arguments: @buf *b@ = pointer to a buffer block |
| 519 | * @ec *p@ = an elliptic curve point |
| 520 | * |
| 521 | * Returns: Zero if it worked, nonzero if there wasn't enough space. |
| 522 | * |
| 523 | * Use: Puts an elliptic curve point to a buffer. |
| 524 | */ |
| 525 | |
| 526 | int buf_putec(buf *b, ec *p) |
| 527 | { |
| 528 | if (EC_ATINF(p)) return (buf_putu16(b, 0)); |
| 529 | if (buf_putmp(b, p->x) || buf_putmp(b, p->y)) return (-1); |
| 530 | return (0); |
| 531 | } |
| 532 | |
| 533 | /*----- That's all, folks -------------------------------------------------*/ |