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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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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 | |
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30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <string.h> |
33 | |
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34 | #include "mp.h" |
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35 | #include "ec.h" |
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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 | |
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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 | |
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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; |
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456 | size_t n; |
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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); |
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461 | n = mp_octets(m); |
462 | if (n != sz && n != 0 && sz != 1) { |
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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); |
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484 | if (!sz) sz = 1; |
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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 | |
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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 | |
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533 | /*----- That's all, folks -------------------------------------------------*/ |