1/* 2 * ==FILEVERSION 980319== 3 * 4 * ppp_deflate.c - interface the zlib procedures for Deflate compression 5 * and decompression (as used by gzip) to the PPP code. 6 * This version is for use with Linux kernel 1.3.X. 7 * 8 * Copyright (c) 1994 The Australian National University. 9 * All rights reserved. 10 * 11 * Permission to use, copy, modify, and distribute this software and its 12 * documentation is hereby granted, provided that the above copyright 13 * notice appears in all copies. This software is provided without any 14 * warranty, express or implied. The Australian National University 15 * makes no representations about the suitability of this software for 16 * any purpose. 17 * 18 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY 19 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 20 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF 21 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY 22 * OF SUCH DAMAGE. 23 * 24 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, 25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 26 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 27 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO 28 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 29 * OR MODIFICATIONS. 30 * 31 * From: deflate.c,v 1.1 1996/01/18 03:17:48 paulus Exp 32 */ 33 34#include <linux/module.h> 35#include <linux/slab.h> 36#include <linux/vmalloc.h> 37#include <linux/init.h> 38#include <linux/string.h> 39 40#include <linux/ppp_defs.h> 41#include <linux/ppp-comp.h> 42 43#include <linux/zlib.h> 44 45/* 46 * State for a Deflate (de)compressor. 47 */ 48struct ppp_deflate_state { 49 int seqno; 50 int w_size; 51 int unit; 52 int mru; 53 int debug; 54 z_stream strm; 55 struct compstat stats; 56}; 57 58#define DEFLATE_OVHD 2 /* Deflate overhead/packet */ 59 60static void *z_comp_alloc(unsigned char *options, int opt_len); 61static void *z_decomp_alloc(unsigned char *options, int opt_len); 62static void z_comp_free(void *state); 63static void z_decomp_free(void *state); 64static int z_comp_init(void *state, unsigned char *options, 65 int opt_len, 66 int unit, int hdrlen, int debug); 67static int z_decomp_init(void *state, unsigned char *options, 68 int opt_len, 69 int unit, int hdrlen, int mru, int debug); 70static int z_compress(void *state, unsigned char *rptr, 71 unsigned char *obuf, 72 int isize, int osize); 73static void z_incomp(void *state, unsigned char *ibuf, int icnt); 74static int z_decompress(void *state, unsigned char *ibuf, 75 int isize, unsigned char *obuf, int osize); 76static void z_comp_reset(void *state); 77static void z_decomp_reset(void *state); 78static void z_comp_stats(void *state, struct compstat *stats); 79 80/** 81 * z_comp_free - free the memory used by a compressor 82 * @arg: pointer to the private state for the compressor. 83 */ 84static void z_comp_free(void *arg) 85{ 86 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 87 88 if (state) { 89 zlib_deflateEnd(&state->strm); 90 vfree(state->strm.workspace); 91 kfree(state); 92 } 93} 94 95/** 96 * z_comp_alloc - allocate space for a compressor. 97 * @options: pointer to CCP option data 98 * @opt_len: length of the CCP option at @options. 99 * 100 * The @options pointer points to the a buffer containing the 101 * CCP option data for the compression being negotiated. It is 102 * formatted according to RFC1979, and describes the window 103 * size that the peer is requesting that we use in compressing 104 * data to be sent to it. 105 * 106 * Returns the pointer to the private state for the compressor, 107 * or NULL if we could not allocate enough memory. 108 */ 109static void *z_comp_alloc(unsigned char *options, int opt_len) 110{ 111 struct ppp_deflate_state *state; 112 int w_size; 113 114 if (opt_len != CILEN_DEFLATE || 115 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || 116 options[1] != CILEN_DEFLATE || 117 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || 118 options[3] != DEFLATE_CHK_SEQUENCE) 119 return NULL; 120 w_size = DEFLATE_SIZE(options[2]); 121 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) 122 return NULL; 123 124 state = kzalloc(sizeof(*state), 125 GFP_KERNEL); 126 if (state == NULL) 127 return NULL; 128 129 state->strm.next_in = NULL; 130 state->w_size = w_size; 131 state->strm.workspace = vmalloc(zlib_deflate_workspacesize()); 132 if (state->strm.workspace == NULL) 133 goto out_free; 134 135 if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, 136 DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY) 137 != Z_OK) 138 goto out_free; 139 return (void *) state; 140 141out_free: 142 z_comp_free(state); 143 return NULL; 144} 145 146/** 147 * z_comp_init - initialize a previously-allocated compressor. 148 * @arg: pointer to the private state for the compressor 149 * @options: pointer to the CCP option data describing the 150 * compression that was negotiated with the peer 151 * @opt_len: length of the CCP option data at @options 152 * @unit: PPP unit number for diagnostic messages 153 * @hdrlen: ignored (present for backwards compatibility) 154 * @debug: debug flag; if non-zero, debug messages are printed. 155 * 156 * The CCP options described by @options must match the options 157 * specified when the compressor was allocated. The compressor 158 * history is reset. Returns 0 for failure (CCP options don't 159 * match) or 1 for success. 160 */ 161static int z_comp_init(void *arg, unsigned char *options, int opt_len, 162 int unit, int hdrlen, int debug) 163{ 164 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 165 166 if (opt_len < CILEN_DEFLATE || 167 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || 168 options[1] != CILEN_DEFLATE || 169 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || 170 DEFLATE_SIZE(options[2]) != state->w_size || 171 options[3] != DEFLATE_CHK_SEQUENCE) 172 return 0; 173 174 state->seqno = 0; 175 state->unit = unit; 176 state->debug = debug; 177 178 zlib_deflateReset(&state->strm); 179 180 return 1; 181} 182 183/** 184 * z_comp_reset - reset a previously-allocated compressor. 185 * @arg: pointer to private state for the compressor. 186 * 187 * This clears the history for the compressor and makes it 188 * ready to start emitting a new compressed stream. 189 */ 190static void z_comp_reset(void *arg) 191{ 192 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 193 194 state->seqno = 0; 195 zlib_deflateReset(&state->strm); 196} 197 198/** 199 * z_compress - compress a PPP packet with Deflate compression. 200 * @arg: pointer to private state for the compressor 201 * @rptr: uncompressed packet (input) 202 * @obuf: compressed packet (output) 203 * @isize: size of uncompressed packet 204 * @osize: space available at @obuf 205 * 206 * Returns the length of the compressed packet, or 0 if the 207 * packet is incompressible. 208 */ 209static int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf, 210 int isize, int osize) 211{ 212 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 213 int r, proto, off, olen, oavail; 214 unsigned char *wptr; 215 216 /* 217 * Check that the protocol is in the range we handle. 218 */ 219 proto = PPP_PROTOCOL(rptr); 220 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) 221 return 0; 222 223 /* Don't generate compressed packets which are larger than 224 the uncompressed packet. */ 225 if (osize > isize) 226 osize = isize; 227 228 wptr = obuf; 229 230 /* 231 * Copy over the PPP header and store the 2-byte sequence number. 232 */ 233 wptr[0] = PPP_ADDRESS(rptr); 234 wptr[1] = PPP_CONTROL(rptr); 235 wptr[2] = PPP_COMP >> 8; 236 wptr[3] = PPP_COMP; 237 wptr += PPP_HDRLEN; 238 wptr[0] = state->seqno >> 8; 239 wptr[1] = state->seqno; 240 wptr += DEFLATE_OVHD; 241 olen = PPP_HDRLEN + DEFLATE_OVHD; 242 state->strm.next_out = wptr; 243 state->strm.avail_out = oavail = osize - olen; 244 ++state->seqno; 245 246 off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */ 247 rptr += off; 248 state->strm.next_in = rptr; 249 state->strm.avail_in = (isize - off); 250 251 for (;;) { 252 r = zlib_deflate(&state->strm, Z_PACKET_FLUSH); 253 if (r != Z_OK) { 254 if (state->debug) 255 printk(KERN_ERR 256 "z_compress: deflate returned %d\n", r); 257 break; 258 } 259 if (state->strm.avail_out == 0) { 260 olen += oavail; 261 state->strm.next_out = NULL; 262 state->strm.avail_out = oavail = 1000000; 263 } else { 264 break; /* all done */ 265 } 266 } 267 olen += oavail - state->strm.avail_out; 268 269 /* 270 * See if we managed to reduce the size of the packet. 271 */ 272 if (olen < isize) { 273 state->stats.comp_bytes += olen; 274 state->stats.comp_packets++; 275 } else { 276 state->stats.inc_bytes += isize; 277 state->stats.inc_packets++; 278 olen = 0; 279 } 280 state->stats.unc_bytes += isize; 281 state->stats.unc_packets++; 282 283 return olen; 284} 285 286/** 287 * z_comp_stats - return compression statistics for a compressor 288 * or decompressor. 289 * @arg: pointer to private space for the (de)compressor 290 * @stats: pointer to a struct compstat to receive the result. 291 */ 292static void z_comp_stats(void *arg, struct compstat *stats) 293{ 294 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 295 296 *stats = state->stats; 297} 298 299/** 300 * z_decomp_free - Free the memory used by a decompressor. 301 * @arg: pointer to private space for the decompressor. 302 */ 303static void z_decomp_free(void *arg) 304{ 305 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 306 307 if (state) { 308 zlib_inflateEnd(&state->strm); 309 kfree(state->strm.workspace); 310 kfree(state); 311 } 312} 313 314/** 315 * z_decomp_alloc - allocate space for a decompressor. 316 * @options: pointer to CCP option data 317 * @opt_len: length of the CCP option at @options. 318 * 319 * The @options pointer points to the a buffer containing the 320 * CCP option data for the compression being negotiated. It is 321 * formatted according to RFC1979, and describes the window 322 * size that we are requesting the peer to use in compressing 323 * data to be sent to us. 324 * 325 * Returns the pointer to the private state for the decompressor, 326 * or NULL if we could not allocate enough memory. 327 */ 328static void *z_decomp_alloc(unsigned char *options, int opt_len) 329{ 330 struct ppp_deflate_state *state; 331 int w_size; 332 333 if (opt_len != CILEN_DEFLATE || 334 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || 335 options[1] != CILEN_DEFLATE || 336 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || 337 options[3] != DEFLATE_CHK_SEQUENCE) 338 return NULL; 339 w_size = DEFLATE_SIZE(options[2]); 340 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) 341 return NULL; 342 343 state = kzalloc(sizeof(*state), GFP_KERNEL); 344 if (state == NULL) 345 return NULL; 346 347 state->w_size = w_size; 348 state->strm.next_out = NULL; 349 state->strm.workspace = kmalloc(zlib_inflate_workspacesize(), 350 GFP_KERNEL|__GFP_REPEAT); 351 if (state->strm.workspace == NULL) 352 goto out_free; 353 354 if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK) 355 goto out_free; 356 return (void *) state; 357 358out_free: 359 z_decomp_free(state); 360 return NULL; 361} 362 363/** 364 * z_decomp_init - initialize a previously-allocated decompressor. 365 * @arg: pointer to the private state for the decompressor 366 * @options: pointer to the CCP option data describing the 367 * compression that was negotiated with the peer 368 * @opt_len: length of the CCP option data at @options 369 * @unit: PPP unit number for diagnostic messages 370 * @hdrlen: ignored (present for backwards compatibility) 371 * @mru: maximum length of decompressed packets 372 * @debug: debug flag; if non-zero, debug messages are printed. 373 * 374 * The CCP options described by @options must match the options 375 * specified when the decompressor was allocated. The decompressor 376 * history is reset. Returns 0 for failure (CCP options don't 377 * match) or 1 for success. 378 */ 379static int z_decomp_init(void *arg, unsigned char *options, int opt_len, 380 int unit, int hdrlen, int mru, int debug) 381{ 382 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 383 384 if (opt_len < CILEN_DEFLATE || 385 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || 386 options[1] != CILEN_DEFLATE || 387 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || 388 DEFLATE_SIZE(options[2]) != state->w_size || 389 options[3] != DEFLATE_CHK_SEQUENCE) 390 return 0; 391 392 state->seqno = 0; 393 state->unit = unit; 394 state->debug = debug; 395 state->mru = mru; 396 397 zlib_inflateReset(&state->strm); 398 399 return 1; 400} 401 402/** 403 * z_decomp_reset - reset a previously-allocated decompressor. 404 * @arg: pointer to private state for the decompressor. 405 * 406 * This clears the history for the decompressor and makes it 407 * ready to receive a new compressed stream. 408 */ 409static void z_decomp_reset(void *arg) 410{ 411 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 412 413 state->seqno = 0; 414 zlib_inflateReset(&state->strm); 415} 416 417/** 418 * z_decompress - decompress a Deflate-compressed packet. 419 * @arg: pointer to private state for the decompressor 420 * @ibuf: pointer to input (compressed) packet data 421 * @isize: length of input packet 422 * @obuf: pointer to space for output (decompressed) packet 423 * @osize: amount of space available at @obuf 424 * 425 * Because of patent problems, we return DECOMP_ERROR for errors 426 * found by inspecting the input data and for system problems, but 427 * DECOMP_FATALERROR for any errors which could possibly be said to 428 * be being detected "after" decompression. For DECOMP_ERROR, 429 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be 430 * infringing a patent of Motorola's if we do, so we take CCP down 431 * instead. 432 * 433 * Given that the frame has the correct sequence number and a good FCS, 434 * errors such as invalid codes in the input most likely indicate a 435 * bug, so we return DECOMP_FATALERROR for them in order to turn off 436 * compression, even though they are detected by inspecting the input. 437 */ 438static int z_decompress(void *arg, unsigned char *ibuf, int isize, 439 unsigned char *obuf, int osize) 440{ 441 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 442 int olen, seq, r; 443 int decode_proto, overflow; 444 unsigned char overflow_buf[1]; 445 446 if (isize <= PPP_HDRLEN + DEFLATE_OVHD) { 447 if (state->debug) 448 printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n", 449 state->unit, isize); 450 return DECOMP_ERROR; 451 } 452 453 /* Check the sequence number. */ 454 seq = (ibuf[PPP_HDRLEN] << 8) + ibuf[PPP_HDRLEN+1]; 455 if (seq != (state->seqno & 0xffff)) { 456 if (state->debug) 457 printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n", 458 state->unit, seq, state->seqno & 0xffff); 459 return DECOMP_ERROR; 460 } 461 ++state->seqno; 462 463 /* 464 * Fill in the first part of the PPP header. The protocol field 465 * comes from the decompressed data. 466 */ 467 obuf[0] = PPP_ADDRESS(ibuf); 468 obuf[1] = PPP_CONTROL(ibuf); 469 obuf[2] = 0; 470 471 /* 472 * Set up to call inflate. We set avail_out to 1 initially so we can 473 * look at the first byte of the output and decide whether we have 474 * a 1-byte or 2-byte protocol field. 475 */ 476 state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD; 477 state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD); 478 state->strm.next_out = obuf + 3; 479 state->strm.avail_out = 1; 480 decode_proto = 1; 481 overflow = 0; 482 483 /* 484 * Call inflate, supplying more input or output as needed. 485 */ 486 for (;;) { 487 r = zlib_inflate(&state->strm, Z_PACKET_FLUSH); 488 if (r != Z_OK) { 489 if (state->debug) 490 printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n", 491 state->unit, r, (state->strm.msg? state->strm.msg: "")); 492 return DECOMP_FATALERROR; 493 } 494 if (state->strm.avail_out != 0) 495 break; /* all done */ 496 if (decode_proto) { 497 state->strm.avail_out = osize - PPP_HDRLEN; 498 if ((obuf[3] & 1) == 0) { 499 /* 2-byte protocol field */ 500 obuf[2] = obuf[3]; 501 --state->strm.next_out; 502 ++state->strm.avail_out; 503 } 504 decode_proto = 0; 505 } else if (!overflow) { 506 /* 507 * We've filled up the output buffer; the only way to 508 * find out whether inflate has any more characters 509 * left is to give it another byte of output space. 510 */ 511 state->strm.next_out = overflow_buf; 512 state->strm.avail_out = 1; 513 overflow = 1; 514 } else { 515 if (state->debug) 516 printk(KERN_DEBUG "z_decompress%d: ran out of mru\n", 517 state->unit); 518 return DECOMP_FATALERROR; 519 } 520 } 521 522 if (decode_proto) { 523 if (state->debug) 524 printk(KERN_DEBUG "z_decompress%d: didn't get proto\n", 525 state->unit); 526 return DECOMP_ERROR; 527 } 528 529 olen = osize + overflow - state->strm.avail_out; 530 state->stats.unc_bytes += olen; 531 state->stats.unc_packets++; 532 state->stats.comp_bytes += isize; 533 state->stats.comp_packets++; 534 535 return olen; 536} 537 538/** 539 * z_incomp - add incompressible input data to the history. 540 * @arg: pointer to private state for the decompressor 541 * @ibuf: pointer to input packet data 542 * @icnt: length of input data. 543 */ 544static void z_incomp(void *arg, unsigned char *ibuf, int icnt) 545{ 546 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; 547 int proto, r; 548 549 /* 550 * Check that the protocol is one we handle. 551 */ 552 proto = PPP_PROTOCOL(ibuf); 553 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) 554 return; 555 556 ++state->seqno; 557 558 /* 559 * We start at the either the 1st or 2nd byte of the protocol field, 560 * depending on whether the protocol value is compressible. 561 */ 562 state->strm.next_in = ibuf + 3; 563 state->strm.avail_in = icnt - 3; 564 if (proto > 0xff) { 565 --state->strm.next_in; 566 ++state->strm.avail_in; 567 } 568 569 r = zlib_inflateIncomp(&state->strm); 570 if (r != Z_OK) { 571 /* gak! */ 572 if (state->debug) { 573 printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n", 574 state->unit, r, (state->strm.msg? state->strm.msg: "")); 575 } 576 return; 577 } 578 579 /* 580 * Update stats. 581 */ 582 state->stats.inc_bytes += icnt; 583 state->stats.inc_packets++; 584 state->stats.unc_bytes += icnt; 585 state->stats.unc_packets++; 586} 587 588/************************************************************* 589 * Module interface table 590 *************************************************************/ 591 592/* These are in ppp_generic.c */ 593extern int ppp_register_compressor (struct compressor *cp); 594extern void ppp_unregister_compressor (struct compressor *cp); 595 596/* 597 * Procedures exported to if_ppp.c. 598 */ 599static struct compressor ppp_deflate = { 600 .compress_proto = CI_DEFLATE, 601 .comp_alloc = z_comp_alloc, 602 .comp_free = z_comp_free, 603 .comp_init = z_comp_init, 604 .comp_reset = z_comp_reset, 605 .compress = z_compress, 606 .comp_stat = z_comp_stats, 607 .decomp_alloc = z_decomp_alloc, 608 .decomp_free = z_decomp_free, 609 .decomp_init = z_decomp_init, 610 .decomp_reset = z_decomp_reset, 611 .decompress = z_decompress, 612 .incomp = z_incomp, 613 .decomp_stat = z_comp_stats, 614 .owner = THIS_MODULE 615}; 616 617static struct compressor ppp_deflate_draft = { 618 .compress_proto = CI_DEFLATE_DRAFT, 619 .comp_alloc = z_comp_alloc, 620 .comp_free = z_comp_free, 621 .comp_init = z_comp_init, 622 .comp_reset = z_comp_reset, 623 .compress = z_compress, 624 .comp_stat = z_comp_stats, 625 .decomp_alloc = z_decomp_alloc, 626 .decomp_free = z_decomp_free, 627 .decomp_init = z_decomp_init, 628 .decomp_reset = z_decomp_reset, 629 .decompress = z_decompress, 630 .incomp = z_incomp, 631 .decomp_stat = z_comp_stats, 632 .owner = THIS_MODULE 633}; 634 635static int __init deflate_init(void) 636{ 637 int answer = ppp_register_compressor(&ppp_deflate); 638 if (answer == 0) 639 printk(KERN_INFO 640 "PPP Deflate Compression module registered\n"); 641 ppp_register_compressor(&ppp_deflate_draft); 642 return answer; 643} 644 645static void __exit deflate_cleanup(void) 646{ 647 ppp_unregister_compressor(&ppp_deflate); 648 ppp_unregister_compressor(&ppp_deflate_draft); 649} 650 651module_init(deflate_init); 652module_exit(deflate_cleanup); 653MODULE_LICENSE("Dual BSD/GPL"); 654MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE)); 655MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT)); 656