1 /* 2 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 * 5 * Because this code is derived from the 4.3BSD compress source: 6 * 7 * Copyright (c) 1985, 1986 The Regents of the University of California. 8 * All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * James A. Woods, derived from original work by Spencer Thomas 12 * and Joseph Orost. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 #pragma ident "%Z%%M% %I% %E% SMI" 44 45 /* 46 * This version is for use with STREAMS in Solaris 2 47 * 48 * $Id: bsd-comp.c,v 1.20 1996/08/28 06:31:57 paulus Exp $ 49 */ 50 51 #include <sys/param.h> 52 #include <sys/types.h> 53 #include <sys/kmem.h> 54 #include <sys/stream.h> 55 #include <sys/cmn_err.h> 56 #include <sys/ddi.h> 57 #include <sys/sunddi.h> 58 #include <sys/byteorder.h> 59 #include <net/ppp_defs.h> 60 61 /* Defined for platform-neutral include file */ 62 #define PACKETPTR mblk_t * 63 #include <net/ppp-comp.h> 64 65 #ifndef _BIG_ENDIAN 66 #define BSD_LITTLE_ENDIAN 67 #endif 68 69 #if DO_BSD_COMPRESS 70 71 /* 72 * PPP "BSD compress" compression 73 * 74 * The differences between this compression and the classic BSD LZW 75 * source are obvious from the requirement that the classic code worked 76 * with files while this handles arbitrarily long streams that 77 * are broken into packets. They are: 78 * 79 * When the code size expands, a block of junk is not emitted by 80 * the compressor and not expected by the decompressor. 81 * 82 * New codes are not necessarily assigned every time an old 83 * code is output by the compressor. This is because a packet 84 * end forces a code to be emitted, but does not imply that a 85 * new sequence has been seen. 86 * 87 * The compression ratio is checked at the first end of a packet 88 * after the appropriate gap. Besides simplifying and speeding 89 * things up, this makes it more likely that the transmitter 90 * and receiver will agree when the dictionary is cleared when 91 * compression is not going well. 92 */ 93 94 /* 95 * A dictionary for doing BSD compress. 96 */ 97 struct bsd_db { 98 int totlen; /* length of this structure */ 99 uint_t hsize; /* size of the hash table */ 100 uint32_t unit; 101 uchar_t hshift; /* used in hash function */ 102 uchar_t n_bits; /* current bits/code */ 103 uchar_t maxbits; 104 uchar_t flags; 105 ushort_t seqno; /* sequence number of next packet */ 106 ushort_t mru; 107 uint_t hdrlen; /* header length to preallocate */ 108 uint_t maxmaxcode; /* largest valid code */ 109 uint_t max_ent; /* largest code in use */ 110 uint_t in_count; /* uncompressed bytes, aged */ 111 uint_t bytes_out; /* compressed bytes, aged */ 112 uint_t ratio; /* recent compression ratio */ 113 uint_t checkpoint; /* when to next check the ratio */ 114 uint_t clear_count; /* times dictionary cleared */ 115 uint_t incomp_count; /* incompressible packets */ 116 uint_t incomp_bytes; /* incompressible bytes */ 117 uint_t uncomp_count; /* uncompressed packets */ 118 uint_t uncomp_bytes; /* uncompressed bytes */ 119 uint_t comp_count; /* compressed packets */ 120 uint_t comp_bytes; /* compressed bytes */ 121 ushort_t *lens; /* array of lengths of codes */ 122 struct bsd_dict { 123 union { /* hash value */ 124 uint32_t fcode; 125 struct { 126 #ifdef BSD_LITTLE_ENDIAN 127 ushort_t prefix; /* preceding code */ 128 uchar_t suffix; /* last character of new code */ 129 uchar_t pad; 130 #else 131 uchar_t pad; 132 uchar_t suffix; /* last character of new code */ 133 ushort_t prefix; /* preceding code */ 134 #endif 135 } hs; 136 } f; 137 ushort_t codem1; /* output of hash table -1 */ 138 ushort_t cptr; /* map code to hash entry */ 139 } dict[1]; 140 }; 141 142 #define BSD_OVHD 2 /* BSD compress overhead/packet */ 143 #define BSD_INIT_BITS BSD_MIN_BITS 144 145 /* db->flags values */ 146 #define DS_DEBUG 0x01 147 #define DS_TESTIN 0x02 148 #define DS_TESTOUT 0x04 149 #define DS_INITDONE 0x08 150 151 static void *bsd_comp_alloc(uchar_t *options, int opt_len); 152 static void *bsd_decomp_alloc(uchar_t *options, int opt_len); 153 static void bsd_free(void *state); 154 static int bsd_comp_init(void *state, uchar_t *options, int opt_len, 155 int unit, int hdrlen, int debug); 156 static int bsd_decomp_init(void *state, uchar_t *options, int opt_len, 157 int unit, int hdrlen, int mru, int debug); 158 static int bsd_compress(void *state, mblk_t **mret, 159 mblk_t *mp, int slen, int maxolen); 160 static int bsd_incomp(void *state, mblk_t *dmsg); 161 static int bsd_decompress(void *state, mblk_t **dmpp); 162 static void bsd_reset(void *state); 163 static void bsd_comp_stats(void *state, struct compstat *stats); 164 static int bsd_set_effort(void *xarg, void *rarg, int effortlevel); 165 166 /* 167 * Procedures exported to ppp_comp.c. 168 */ 169 struct compressor ppp_bsd_compress = { 170 CI_BSD_COMPRESS, /* compress_proto */ 171 bsd_comp_alloc, /* comp_alloc */ 172 bsd_free, /* comp_free */ 173 bsd_comp_init, /* comp_init */ 174 bsd_reset, /* comp_reset */ 175 bsd_compress, /* compress */ 176 bsd_comp_stats, /* comp_stat */ 177 bsd_decomp_alloc, /* decomp_alloc */ 178 bsd_free, /* decomp_free */ 179 bsd_decomp_init, /* decomp_init */ 180 bsd_reset, /* decomp_reset */ 181 bsd_decompress, /* decompress */ 182 bsd_incomp, /* incomp */ 183 bsd_comp_stats, /* decomp_stat */ 184 bsd_set_effort, /* set_effort */ 185 }; 186 187 /* 188 * the next two codes should not be changed lightly, as they must not 189 * lie within the contiguous general code space. 190 */ 191 #define CLEAR 256 /* table clear output code */ 192 #define FIRST 257 /* first free entry */ 193 #define LAST 255 194 195 #define MAXCODE(b) ((1 << (b)) - 1) 196 #define BADCODEM1 MAXCODE(BSD_MAX_BITS) 197 198 #define BSD_HASH(prefix, suffix, hshift) \ 199 ((((uint32_t)(suffix)) << (hshift)) ^ (uint32_t)(prefix)) 200 201 #define BSD_KEY(prefix, suffix) \ 202 ((((uint32_t)(suffix)) << 16) + (uint32_t)(prefix)) 203 204 #define CHECK_GAP 10000 /* Ratio check interval */ 205 206 #define RATIO_SCALE_LOG 8 207 #define RATIO_SCALE (1 << RATIO_SCALE_LOG) 208 #define RATIO_MAX (0x7fffffff >> RATIO_SCALE_LOG) 209 210 #define DECOMP_CHUNK 256 211 212 /* 213 * bsd_clear() 214 * 215 * clear the dictionary 216 */ 217 static void 218 bsd_clear(struct bsd_db *db) 219 { 220 db->clear_count++; 221 db->max_ent = FIRST-1; 222 db->n_bits = BSD_INIT_BITS; 223 db->ratio = 0; 224 db->bytes_out = 0; 225 db->in_count = 0; 226 db->checkpoint = CHECK_GAP; 227 } 228 229 /* 230 * bsd_check() 231 * 232 * If the dictionary is full, then see if it is time to reset it. 233 * 234 * Compute the compression ratio using fixed-point arithmetic 235 * with 8 fractional bits. 236 * 237 * Since we have an infinite stream instead of a single file, 238 * watch only the local compression ratio. 239 * 240 * Since both peers must reset the dictionary at the same time even in 241 * the absence of CLEAR codes (while packets are incompressible), they 242 * must compute the same ratio. 243 */ 244 static int /* 1=output CLEAR */ 245 bsd_check(struct bsd_db *db) 246 { 247 uint_t new_ratio; 248 249 if (db->in_count >= db->checkpoint) { 250 251 /* 252 * age the ratio by limiting the size of the counts 253 */ 254 if (db->in_count >= RATIO_MAX || db->bytes_out >= RATIO_MAX) { 255 db->in_count -= db->in_count/4; 256 db->bytes_out -= db->bytes_out/4; 257 } 258 259 db->checkpoint = db->in_count + CHECK_GAP; 260 261 if (db->max_ent >= db->maxmaxcode) { 262 263 /* 264 * Reset the dictionary only if the ratio is worse, 265 * or if it looks as if it has been poisoned 266 * by incompressible data. 267 * 268 * This does not overflow, because 269 * db->in_count <= RATIO_MAX. 270 */ 271 new_ratio = db->in_count << RATIO_SCALE_LOG; 272 273 if (db->bytes_out != 0) { 274 new_ratio /= db->bytes_out; 275 } 276 277 if (new_ratio < db->ratio || 278 new_ratio < 1 * RATIO_SCALE) { 279 bsd_clear(db); 280 return (1); 281 } 282 283 db->ratio = new_ratio; 284 } 285 } 286 287 return (0); 288 } 289 290 /* 291 * bsd_comp_stats() 292 * 293 * Return statistics. 294 */ 295 static void 296 bsd_comp_stats(void *state, struct compstat *stats) 297 { 298 struct bsd_db *db = (struct bsd_db *)state; 299 uint_t out; 300 301 stats->unc_bytes = db->uncomp_bytes; 302 stats->unc_packets = db->uncomp_count; 303 stats->comp_bytes = db->comp_bytes; 304 stats->comp_packets = db->comp_count; 305 stats->inc_bytes = db->incomp_bytes; 306 stats->inc_packets = db->incomp_count; 307 stats->ratio = db->in_count; 308 309 out = db->bytes_out; 310 311 if (stats->ratio <= 0x7fffff) { 312 stats->ratio <<= 8; 313 } else { 314 out >>= 8; 315 } 316 317 if (out != 0) { 318 stats->ratio /= out; 319 } 320 } 321 322 /* 323 * bsd_reset() 324 * 325 * Reset state, as on a CCP ResetReq. 326 */ 327 static void 328 bsd_reset(void *state) 329 { 330 struct bsd_db *db = (struct bsd_db *)state; 331 332 if (db->hsize != 0) { 333 db->seqno = 0; 334 335 bsd_clear(db); 336 337 db->clear_count = 0; 338 } 339 } 340 341 /* 342 * bsd_alloc() 343 * 344 * Allocate space for a (de) compressor. 345 */ 346 static void * 347 bsd_alloc(uchar_t *options, int opt_len, int decomp) 348 { 349 int bits; 350 uint_t newlen; 351 uint_t hsize; 352 uint_t hshift; 353 uint_t maxmaxcode; 354 uint_t ilen; 355 struct bsd_db *db; 356 357 if (opt_len != 3 || 358 options[0] != CI_BSD_COMPRESS || 359 options[1] != 3 || 360 BSD_VERSION(options[2]) != BSD_CURRENT_VERSION) { 361 362 return (NULL); 363 } 364 365 bits = BSD_NBITS(options[2]); 366 367 switch (bits) { 368 369 case 9: /* needs 82152 for both directions */ 370 case 10: /* needs 84144 */ 371 case 11: /* needs 88240 */ 372 case 12: /* needs 96432 */ 373 374 hsize = 5003; 375 hshift = 4; 376 377 break; 378 379 case 13: /* needs 176784 */ 380 381 hsize = 9001; 382 hshift = 5; 383 384 break; 385 386 case 14: /* needs 353744 */ 387 388 hsize = 18013; 389 hshift = 6; 390 391 break; 392 393 case 15: /* needs 691440 */ 394 395 hsize = 35023; 396 hshift = 7; 397 398 break; 399 400 /* XXX: this falls thru - it was originally commented */ 401 case 16: /* needs 1366160--far too much, */ 402 /* hsize = 69001; */ /* and 69001 is too big for cptr */ 403 /* hshift = 8; */ /* in struct bsd_db */ 404 /* break; */ 405 406 default: 407 408 return (NULL); 409 } 410 411 maxmaxcode = MAXCODE(bits); 412 ilen = newlen = sizeof (*db) + (hsize-1) * sizeof (db->dict[0]); 413 if (decomp) 414 newlen += (maxmaxcode+1) * sizeof (db->lens[0]); 415 db = (struct bsd_db *)kmem_alloc(newlen, KM_NOSLEEP); 416 if (!db) { 417 return (NULL); 418 } 419 420 bzero(db, sizeof (*db) - sizeof (db->dict)); 421 422 if (!decomp) { 423 db->lens = NULL; 424 } else { 425 db->lens = (ushort_t *)((caddr_t)db + ilen); 426 } 427 428 db->totlen = newlen; 429 db->hsize = hsize; 430 db->hshift = (uchar_t)hshift; 431 db->maxmaxcode = maxmaxcode; 432 db->maxbits = (uchar_t)bits; 433 434 return ((void *)db); 435 } 436 437 /* 438 * bsd_free() 439 */ 440 static void 441 bsd_free(void *state) 442 { 443 struct bsd_db *db = (struct bsd_db *)state; 444 445 if (db->hsize != 0) { 446 /* XXX feeble attempt to catch bad references. */ 447 db->hsize = 0; 448 449 kmem_free(db, db->totlen); 450 } 451 } 452 453 /* 454 * bsd_comp_alloc() 455 */ 456 static void * 457 bsd_comp_alloc(uchar_t *options, int opt_len) 458 { 459 return (bsd_alloc(options, opt_len, 0)); 460 } 461 462 /* 463 * bsd_decomp_alloc() 464 */ 465 static void * 466 bsd_decomp_alloc(uchar_t *options, int opt_len) 467 { 468 return (bsd_alloc(options, opt_len, 1)); 469 } 470 471 /* 472 * bsd_init() 473 * 474 * Initialize the database. 475 */ 476 static int 477 bsd_init(struct bsd_db *db, uchar_t *options, int opt_len, int unit, 478 int hdrlen, int mru, int debug, int decomp) 479 { 480 int i; 481 482 if (db->hsize == 0 || opt_len < CILEN_BSD_COMPRESS || 483 options[0] != CI_BSD_COMPRESS || 484 options[1] != CILEN_BSD_COMPRESS || 485 BSD_VERSION(options[2]) != BSD_CURRENT_VERSION || 486 BSD_NBITS(options[2]) != db->maxbits || 487 decomp && db->lens == NULL) { 488 489 return (0); 490 } 491 492 if (decomp) { 493 i = LAST + 1; 494 495 while (i != 0) { 496 db->lens[--i] = 1; 497 } 498 } 499 500 i = db->hsize; 501 502 while (i != 0) { 503 db->dict[--i].codem1 = BADCODEM1; 504 db->dict[i].cptr = 0; 505 } 506 507 db->unit = unit; 508 db->hdrlen = hdrlen; 509 db->mru = (ushort_t)mru; 510 511 if (debug) { 512 db->flags |= DS_DEBUG; 513 } 514 515 bsd_reset(db); 516 517 db->flags |= DS_INITDONE; 518 519 return (1); 520 } 521 522 /* 523 * bsd_comp_init() 524 */ 525 static int 526 bsd_comp_init(void *state, uchar_t *options, int opt_len, int unit, int hdrlen, 527 int debug) 528 { 529 return (bsd_init((struct bsd_db *)state, options, opt_len, 530 unit, hdrlen, 0, debug, 0)); 531 } 532 533 /* 534 * bsd_decomp_init() 535 */ 536 static int 537 bsd_decomp_init(void *state, uchar_t *options, int opt_len, int unit, 538 int hdrlen, int mru, int debug) 539 { 540 return (bsd_init((struct bsd_db *)state, options, opt_len, 541 unit, hdrlen, mru, debug, 1)); 542 } 543 544 545 /* 546 * bsd_compress() 547 * 548 * compress a packet 549 * One change from the BSD compress command is that when the 550 * code size expands, we do not output a bunch of padding. 551 * 552 * N.B. at present, we ignore the hdrlen specified in the comp_init call. 553 */ 554 static int /* new slen */ 555 bsd_compress(void *state, mblk_t **mretp, mblk_t *mp, int slen, int maxolen) 556 { 557 struct bsd_db *db = (struct bsd_db *)state; 558 int hshift = db->hshift; 559 uint_t max_ent = db->max_ent; 560 uint_t n_bits = db->n_bits; 561 uint_t bitno = 32; 562 uint32_t accm = 0; 563 uint32_t fcode; 564 struct bsd_dict *dictp; 565 uchar_t c; 566 int hval; 567 int disp; 568 int ent; 569 int ilen = slen - (PPP_HDRLEN-1); 570 mblk_t *mret; 571 uchar_t *rptr, *rmax; 572 uchar_t *wptr; 573 uchar_t *cp_end; 574 int olen; 575 mblk_t *m; 576 mblk_t **mnp; 577 #if defined(lint) || defined(_lint) 578 uchar_t hdlcaddr, hdlcctl; 579 #else 580 int hdlcaddr, hdlcctl; 581 #endif 582 583 ASSERT(db->flags & DS_INITDONE); 584 585 #define PUTBYTE(v) { \ 586 if (wptr) { \ 587 *wptr++ = (v); \ 588 if (wptr >= cp_end) { \ 589 m->b_wptr = wptr; \ 590 m = m->b_cont; \ 591 if (m) { \ 592 wptr = m->b_wptr; \ 593 cp_end = m->b_datap->db_lim; \ 594 } else { \ 595 wptr = NULL; \ 596 } \ 597 } \ 598 } \ 599 ++olen; \ 600 } 601 602 #define OUTPUT(ent) { \ 603 bitno -= n_bits; \ 604 accm |= ((ent) << bitno); \ 605 do { \ 606 PUTBYTE(accm >> 24); \ 607 accm <<= 8; \ 608 bitno += 8; \ 609 } while (bitno <= 24); \ 610 } 611 612 #define ADJRPTR() { \ 613 if (rptr != NULL) { \ 614 while (rptr >= rmax) { \ 615 if ((mp = mp->b_cont) == NULL) { \ 616 rptr = NULL; \ 617 break; \ 618 } \ 619 rptr = mp->b_rptr; \ 620 rmax = mp->b_wptr; \ 621 } \ 622 } \ 623 } 624 625 #define GETBYTE(v) { \ 626 if (rptr != NULL) { \ 627 (v) = *rptr++; \ 628 } \ 629 } 630 631 if (db->hsize == 0) 632 return (-1); 633 634 /* 635 * First get the protocol and check that we're 636 * interested in this packet. 637 */ 638 *mretp = NULL; 639 rptr = mp->b_rptr; 640 rmax = mp->b_wptr; 641 642 /* We CANNOT do a pullup here; it's not our buffer to toy with. */ 643 ADJRPTR(); 644 GETBYTE(hdlcaddr); 645 ADJRPTR(); 646 GETBYTE(hdlcctl); 647 ADJRPTR(); 648 GETBYTE(ent); 649 ADJRPTR(); 650 651 /* 652 * Per RFC 1977, the protocol field must be compressed using a 653 * PFC-like procedure. Also, all protocols between 0000-3FFF 654 * except the two compression protocols must be LZ compressed. 655 */ 656 if (ent == 0) { 657 GETBYTE(ent); 658 if (rptr == NULL || ent == PPP_COMP || ent == PPP_COMPFRAG) 659 return (0); 660 } else { 661 if (ent > 0x3F) 662 return (0); 663 ilen++; 664 } 665 666 /* 667 * Don't generate compressed packets that are larger than the 668 * source (uncompressed) packet. 669 */ 670 if (maxolen > slen) { 671 maxolen = slen; 672 } 673 if (maxolen < 6) 674 maxolen = 6; 675 676 /* 677 * Allocate enough message blocks to give maxolen total space 678 */ 679 mnp = &mret; 680 for (olen = maxolen; olen > 0; ) { 681 682 m = allocb((olen < 4096? olen: 4096), BPRI_MED); 683 684 *mnp = m; 685 if (m == NULL) { 686 if (mnp == &mret) 687 return (0); 688 /* We allocated some; hope for the best. */ 689 break; 690 } 691 692 mnp = &m->b_cont; 693 olen -= m->b_datap->db_lim - m->b_wptr; 694 } 695 696 *mnp = NULL; 697 698 m = mret; 699 wptr = m->b_wptr; 700 cp_end = m->b_datap->db_lim; 701 702 olen = 0; 703 704 /* 705 * Copy the PPP header over, changing the protocol, 706 * and install the 2-byte sequence number 707 */ 708 *wptr++ = hdlcaddr; 709 *wptr++ = hdlcctl; 710 *wptr++ = PPP_COMP>>8; /* change the protocol */ 711 *wptr++ = PPP_COMP; 712 *wptr++ = db->seqno >> 8; 713 *wptr++ = db->seqno; 714 715 #ifdef DEBUG 716 /* 717 * If testing output, just garbling the sequence here does the 718 * trick. 719 */ 720 if ((db->flags & DS_TESTOUT) && (db->seqno % 100) == 50) 721 wptr[-1] ^= 0xAA; 722 #endif 723 724 ++db->seqno; 725 726 for (;;) { 727 ADJRPTR(); 728 if (rptr == NULL) 729 break; 730 731 GETBYTE(c); 732 733 fcode = BSD_KEY(ent, c); 734 hval = BSD_HASH(ent, c, hshift); 735 736 dictp = &db->dict[hval]; 737 738 /* 739 * Validate and then check the entry 740 */ 741 if (dictp->codem1 >= max_ent) { 742 goto nomatch; 743 } 744 745 if (dictp->f.fcode == fcode) { 746 ent = dictp->codem1+1; 747 748 /* 749 * found (prefix,suffix) 750 */ 751 continue; 752 } 753 754 /* 755 * continue probing until a match or invalid entry 756 */ 757 disp = (hval == 0) ? 1 : hval; 758 759 do { 760 hval += disp; 761 if (hval >= db->hsize) { 762 hval -= db->hsize; 763 if (hval >= db->hsize) { 764 if (db->flags & DS_DEBUG) { 765 cmn_err(CE_CONT, 766 "bsd_comp%d: internal " 767 "error\n", 768 db->unit); 769 } 770 /* Caller will free it all */ 771 return (-1); 772 } 773 } 774 775 dictp = &db->dict[hval]; 776 777 if (dictp->codem1 >= max_ent) { 778 goto nomatch; 779 } 780 } while (dictp->f.fcode != fcode); 781 782 /* 783 * finally found (prefix,suffix) 784 */ 785 ent = dictp->codem1 + 1; 786 787 continue; 788 789 nomatch: 790 /* 791 * output the prefix 792 */ 793 OUTPUT(ent); 794 795 /* 796 * code -> hashtable 797 */ 798 if (max_ent < db->maxmaxcode) { 799 struct bsd_dict *dictp2; 800 801 /* 802 * expand code size if needed 803 */ 804 if (max_ent >= MAXCODE(n_bits)) { 805 db->n_bits = ++n_bits; 806 } 807 808 /* 809 * Invalidate old hash table entry using 810 * this code, and then take it over. 811 */ 812 dictp2 = &db->dict[max_ent+1]; 813 814 if (db->dict[dictp2->cptr].codem1 == max_ent) { 815 db->dict[dictp2->cptr].codem1 = BADCODEM1; 816 } 817 818 dictp2->cptr = (ushort_t)hval; 819 dictp->codem1 = max_ent; 820 dictp->f.fcode = fcode; 821 822 db->max_ent = ++max_ent; 823 } 824 825 ent = c; 826 } 827 828 /* 829 * output the last code 830 */ 831 OUTPUT(ent); 832 833 olen += (32-bitno+7)/8; /* count complete bytes */ 834 835 db->bytes_out += olen; 836 db->in_count += ilen; 837 838 if (bsd_check(db)) { 839 OUTPUT(CLEAR); /* do not count the CLEAR */ 840 } 841 842 /* 843 * Pad dribble bits of last code with ones. 844 * Do not emit a completely useless byte of ones. 845 */ 846 if (bitno != 32) { 847 PUTBYTE((accm | (0xff << (bitno - 8))) >> 24); 848 } 849 850 /* 851 * Increase code size if we would have without the packet 852 * boundary and as the decompressor will. 853 */ 854 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) { 855 db->n_bits++; 856 } 857 858 db->uncomp_bytes += ilen; 859 ++db->uncomp_count; 860 861 if (wptr == NULL || olen + PPP_HDRLEN + BSD_OVHD >= maxolen) { 862 /* 863 * throw away the compressed stuff if it is longer 864 * than uncompressed 865 */ 866 freemsg(mret); 867 868 mret = NULL; 869 870 ++db->incomp_count; 871 db->incomp_bytes += ilen; 872 873 } else { 874 875 m->b_wptr = wptr; 876 if (m->b_cont) { 877 freemsg(m->b_cont); 878 m->b_cont = NULL; 879 } 880 881 ++db->comp_count; 882 db->comp_bytes += olen + BSD_OVHD; 883 } 884 885 *mretp = mret; 886 887 return (olen + PPP_HDRLEN + BSD_OVHD); 888 #undef OUTPUT 889 #undef PUTBYTE 890 } 891 892 893 /* 894 * bsd_incomp() 895 * 896 * Update the "BSD Compress" dictionary on the receiver for 897 * incompressible data by pretending to compress the incoming data. 898 */ 899 static int 900 bsd_incomp(void *state, mblk_t *mp) 901 { 902 struct bsd_db *db = (struct bsd_db *)state; 903 uint_t hshift = db->hshift; 904 uint_t max_ent = db->max_ent; 905 uint_t n_bits = db->n_bits; 906 struct bsd_dict *dictp; 907 uint32_t fcode; 908 uchar_t c; 909 long hval; 910 long disp; 911 int slen; 912 int ilen; 913 uint_t bitno = 7; 914 uchar_t *rptr, *rmax; 915 uint_t ent; 916 917 ASSERT(db->flags & DS_INITDONE); 918 919 if (db->hsize == 0) 920 return (-1); 921 922 rptr = mp->b_rptr; 923 rmax = mp->b_wptr; 924 ADJRPTR(); 925 GETBYTE(ent); /* address */ 926 ADJRPTR(); 927 GETBYTE(ent); /* control */ 928 ADJRPTR(); 929 GETBYTE(ent); /* protocol high */ 930 ADJRPTR(); 931 932 /* 933 * Per RFC 1977, the protocol field must be compressed using a 934 * PFC-like procedure. Also, all protocols between 0000-3FFF 935 * except the two compression protocols must be LZ compressed. 936 */ 937 ilen = 1; /* count the protocol as 1 byte */ 938 if (ent == 0) { 939 GETBYTE(ent); 940 if (rptr == NULL || ent == PPP_COMP || ent == PPP_COMPFRAG) 941 return (0); 942 } else { 943 if (ent > 0x3F) 944 return (0); 945 ilen++; 946 } 947 948 db->seqno++; 949 950 for (;;) { 951 952 slen = mp->b_wptr - rptr; 953 if (slen <= 0) { 954 mp = mp->b_cont; 955 if (!mp) { 956 break; 957 } 958 959 rptr = mp->b_rptr; 960 continue; /* skip zero-length buffers */ 961 } 962 963 ilen += slen; 964 965 do { 966 c = *rptr++; 967 968 fcode = BSD_KEY(ent, c); 969 hval = BSD_HASH(ent, c, hshift); 970 971 dictp = &db->dict[hval]; 972 973 /* 974 * validate and then check the entry 975 */ 976 if (dictp->codem1 >= max_ent) { 977 goto nomatch; 978 } 979 980 if (dictp->f.fcode == fcode) { 981 ent = dictp->codem1 + 1; 982 continue; /* found (prefix,suffix) */ 983 } 984 985 /* 986 * continue probing until a match or invalid entry 987 */ 988 disp = (hval == 0) ? 1 : hval; 989 do { 990 hval += disp; 991 if (hval >= db->hsize) { 992 hval -= db->hsize; 993 if (hval >= db->hsize) { 994 if (db->flags & DS_DEBUG) { 995 cmn_err(CE_CONT, 996 "bsd_incomp%d: " 997 "internal error\n", 998 db->unit); 999 } 1000 return (-1); 1001 } 1002 } 1003 1004 dictp = &db->dict[hval]; 1005 if (dictp->codem1 >= max_ent) { 1006 goto nomatch; 1007 } 1008 } while (dictp->f.fcode != fcode); 1009 1010 ent = dictp->codem1+1; 1011 continue; /* finally found (prefix,suffix) */ 1012 1013 nomatch: /* output (count) the prefix */ 1014 bitno += n_bits; 1015 1016 /* 1017 * code -> hashtable 1018 */ 1019 if (max_ent < db->maxmaxcode) { 1020 struct bsd_dict *dictp2; 1021 1022 /* 1023 * expand code size if needed 1024 */ 1025 if (max_ent >= MAXCODE(n_bits)) { 1026 db->n_bits = ++n_bits; 1027 } 1028 1029 /* 1030 * Invalidate previous hash table entry 1031 * assigned this code, and then take it over. 1032 */ 1033 dictp2 = &db->dict[max_ent+1]; 1034 if (db->dict[dictp2->cptr].codem1 == max_ent) { 1035 db->dict[dictp2->cptr].codem1 = 1036 BADCODEM1; 1037 } 1038 1039 dictp2->cptr = (ushort_t)hval; 1040 dictp->codem1 = max_ent; 1041 dictp->f.fcode = fcode; 1042 1043 db->max_ent = ++max_ent; 1044 db->lens[max_ent] = db->lens[ent]+1; 1045 } 1046 1047 ent = c; 1048 } while (--slen != 0); 1049 } 1050 1051 bitno += n_bits; /* output (count) the last code */ 1052 1053 db->bytes_out += bitno/8; 1054 db->in_count += ilen; 1055 1056 (void) bsd_check(db); 1057 1058 ++db->incomp_count; 1059 db->incomp_bytes += ilen; 1060 ++db->uncomp_count; 1061 db->uncomp_bytes += ilen; 1062 1063 /* 1064 * Increase code size if we would have without the packet 1065 * boundary and as the decompressor will. 1066 */ 1067 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) { 1068 db->n_bits++; 1069 } 1070 return (0); 1071 #undef ADJRPTR 1072 } 1073 1074 1075 /* 1076 * bsd_decompress() 1077 * 1078 * Decompress "BSD Compress" 1079 * 1080 * Because of patent problems, we return DECOMP_ERROR for errors 1081 * found by inspecting the input data and for system problems, but 1082 * DECOMP_FATALERROR for any errors which could possibly be said to 1083 * be being detected "after" decompression. For DECOMP_ERROR, 1084 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be 1085 * infringing a patent of Motorola's if we do, so we take CCP down 1086 * instead. 1087 * 1088 * Given that the frame has the correct sequence number and a good FCS, 1089 * errors such as invalid codes in the input most likely indicate a 1090 * bug, so we return DECOMP_FATALERROR for them in order to turn off 1091 * compression, even though they are detected by inspecting the input. 1092 */ 1093 static int 1094 bsd_decompress(void *state, mblk_t **dmpp) 1095 { 1096 mblk_t *cmsg = *dmpp, *mnext; 1097 struct bsd_db *db = (struct bsd_db *)state; 1098 uint_t max_ent = db->max_ent; 1099 uint32_t accm = 0; 1100 uint_t bitno = 32; /* 1st valid bit in accm */ 1101 uint_t n_bits = db->n_bits; 1102 uint_t tgtbitno = 32 - n_bits; /* bitno when we have a code */ 1103 struct bsd_dict *dictp; 1104 int explen; 1105 int seq; 1106 uint_t incode; 1107 uint_t oldcode; 1108 uint_t finchar = 0, ofinchar; 1109 uchar_t *p; 1110 uchar_t *rptr, *rmax; 1111 uchar_t *wptr, *prepos; 1112 mblk_t *dmsg; 1113 mblk_t *mret; 1114 int ilen; 1115 int dlen; 1116 int codelen; 1117 int extra; 1118 int decode_proto; 1119 int blockctr; 1120 int outlen; 1121 #if defined(lint) || defined(_lint) 1122 uchar_t adrs, ctrl; 1123 #else 1124 int adrs, ctrl; 1125 #endif 1126 1127 ASSERT(db->flags & DS_INITDONE); 1128 1129 /* Note: spppcomp already did a pullup to fix the first buffer. */ 1130 *dmpp = NULL; 1131 rptr = cmsg->b_rptr; 1132 rmax = cmsg->b_wptr; 1133 ilen = 0; 1134 1135 /* 1136 * Note that we free as we go. If we fail to decompress, 1137 * there's nothing good that the caller can do. 1138 */ 1139 #define ADJRPTR() \ 1140 while (rptr >= rmax) { \ 1141 mnext = cmsg->b_cont; \ 1142 freeb(cmsg); \ 1143 if ((cmsg = mnext) == NULL) { \ 1144 rptr = NULL; \ 1145 break; \ 1146 } \ 1147 rptr = cmsg->b_rptr; \ 1148 rmax = cmsg->b_wptr; \ 1149 ilen += rmax-rptr; \ 1150 } 1151 1152 /* 1153 * Save the address/control from the PPP header 1154 * and then get the sequence number. 1155 */ 1156 adrs = rptr[0]; 1157 ctrl = rptr[1]; 1158 rptr += 4; 1159 ADJRPTR(); 1160 seq = rptr == NULL ? 0 : (*rptr++ << 8); 1161 ADJRPTR(); 1162 if (rptr == NULL) { 1163 if (db->flags & DS_DEBUG) { 1164 cmn_err(CE_CONT, "bsd_decomp%d: bad buffer\n", 1165 db->unit); 1166 } 1167 return (DECOMP_ERROR); 1168 } 1169 seq |= *rptr++; 1170 1171 #ifdef DEBUG 1172 /* 1173 * If testing input, just pretending the sequence is bad here 1174 * does the trick. 1175 */ 1176 if ((db->flags & DS_TESTIN) && (db->seqno % 300) == 101) 1177 seq ^= 0x55; 1178 #endif 1179 1180 /* 1181 * Check the sequence number and give up if it is not what we expect. 1182 */ 1183 if (db->hsize == 0 || seq != db->seqno++) { 1184 freemsg(cmsg); 1185 if (db->flags & DS_DEBUG) { 1186 cmn_err(CE_CONT, "bsd_decomp%d: bad sequence # %d, " 1187 "expected %d\n", db->unit, seq, db->seqno - 1); 1188 } 1189 1190 return (DECOMP_ERROR); 1191 } 1192 1193 /* 1194 * Allocate one message block to start with. 1195 */ 1196 if ((dmsg = allocb(DECOMP_CHUNK + db->hdrlen, BPRI_MED)) == NULL) { 1197 freemsg(cmsg); 1198 if (db->flags & DS_DEBUG) { 1199 cmn_err(CE_CONT, 1200 "bsd_decomp%d: can't allocate first buffer\n", 1201 db->unit); 1202 } 1203 return (DECOMP_ERROR); 1204 } 1205 1206 /* 1207 * Avoid an error that might cause us to allocate all available memory. 1208 * Enforce a maximum number of blocks to allocate for message. We add 1209 * a fudge factor of 5 extra blocks, in order to avoid unnecessary 1210 * DECOMP_ERROR when the code size is small (9). 1211 */ 1212 blockctr = ((db->mru + 32 + DECOMP_CHUNK - 1) / DECOMP_CHUNK) + 5; 1213 1214 mret = dmsg; 1215 dmsg->b_wptr += db->hdrlen; 1216 dmsg->b_rptr = wptr = dmsg->b_wptr; 1217 1218 /* 1219 * Insert PPP header. This shouldn't be needed! 1220 */ 1221 *wptr++ = adrs; 1222 *wptr++ = ctrl; 1223 prepos = wptr; 1224 *wptr++ = 0; 1225 dmsg->b_wptr = wptr; 1226 1227 explen = dmsg->b_datap->db_lim - wptr; 1228 oldcode = CLEAR; 1229 ilen = rmax-rptr; 1230 1231 outlen = 0; 1232 decode_proto = 1; 1233 for (;;) { 1234 ADJRPTR(); 1235 if (rptr == NULL) 1236 break; 1237 1238 /* 1239 * Accumulate bytes until we have a complete code. 1240 * Then get the next code, relying on the 32-bit, 1241 * unsigned accm to mask the result. 1242 */ 1243 bitno -= 8; 1244 1245 accm |= *rptr++ << bitno; 1246 1247 if (tgtbitno < bitno) { 1248 continue; 1249 } 1250 1251 incode = accm >> tgtbitno; 1252 accm <<= n_bits; 1253 bitno += n_bits; 1254 1255 if (incode == CLEAR) { 1256 1257 /* 1258 * The dictionary must only be cleared at 1259 * the end of a packet. But there could be an 1260 * empty message block at the end. 1261 */ 1262 ADJRPTR(); 1263 if (rptr != NULL) { 1264 freemsg(mret); 1265 freemsg(cmsg); 1266 if (db->flags & DS_DEBUG) { 1267 cmn_err(CE_CONT, 1268 "bsd_decomp%d: bad CLEAR\n", 1269 db->unit); 1270 } 1271 1272 return (DECOMP_FATALERROR); 1273 } 1274 1275 bsd_clear(db); 1276 /* Have to keep cleared state variables! */ 1277 outlen += wptr-dmsg->b_wptr; 1278 dmsg->b_wptr = wptr; 1279 db->comp_bytes += ilen; 1280 ilen = 0; 1281 break; 1282 } 1283 1284 /* 1285 * Special case for KwKwK string 1286 */ 1287 ofinchar = finchar; 1288 if (incode > max_ent) { 1289 if (incode > max_ent + 2 || 1290 incode > db->maxmaxcode || 1291 oldcode == CLEAR) { 1292 freemsg(cmsg); 1293 freemsg(mret); 1294 1295 /* probably a bug if we get here */ 1296 if (db->flags & DS_DEBUG) { 1297 cmn_err(CE_CONT, 1298 "bsd_decomp%d: bad code 0x%x " 1299 "oldcode=0x%x ", db->unit, incode, 1300 oldcode); 1301 } 1302 1303 return (DECOMP_FATALERROR); 1304 } 1305 finchar = oldcode; 1306 extra = 1; 1307 } else { 1308 finchar = incode; 1309 extra = 0; 1310 } 1311 codelen = db->lens[finchar]; 1312 1313 /* 1314 * Decode this code and install it in the decompressed buffer 1315 */ 1316 explen -= codelen + extra; 1317 if (explen < 0) { 1318 /* 1319 * Allocate another message block 1320 */ 1321 dlen = wptr - dmsg->b_wptr; 1322 outlen += dlen; 1323 db->in_count += dlen; 1324 dmsg->b_wptr = wptr; 1325 dlen = codelen + extra; 1326 1327 if (dlen < DECOMP_CHUNK) { 1328 dlen = DECOMP_CHUNK; 1329 } 1330 1331 if ((--blockctr < 0) || 1332 (dmsg->b_cont = allocb(dlen, BPRI_MED)) == NULL) { 1333 freemsg(cmsg); 1334 freemsg(mret); 1335 if (db->flags & DS_DEBUG) { 1336 cmn_err(CE_CONT, 1337 "bsd_decomp%d: %s output " 1338 "buffers; outlen %d+%d\n", 1339 db->unit, 1340 (blockctr < 0 ? "too many" : 1341 "can't allocate"), 1342 outlen, dlen); 1343 } 1344 return (DECOMP_ERROR); 1345 } 1346 1347 dmsg = dmsg->b_cont; 1348 wptr = dmsg->b_wptr; 1349 explen = dmsg->b_datap->db_lim - wptr - codelen - 1350 extra; 1351 } 1352 1353 p = (wptr += codelen); 1354 1355 while (finchar > LAST) { 1356 dictp = &db->dict[db->dict[finchar].cptr]; 1357 *--p = dictp->f.hs.suffix; 1358 finchar = dictp->f.hs.prefix; 1359 } 1360 1361 *--p = finchar; 1362 1363 if (decode_proto) { 1364 decode_proto = 0; 1365 /* Wow, is *this* ugly! */ 1366 if (!(finchar & 1)) { 1367 if (p == prepos+1) { 1368 bcopy(p, prepos, wptr-p); 1369 wptr--; 1370 explen++; 1371 db->in_count++; 1372 } else { 1373 /* This is safe, but doesn't look it */ 1374 *prepos = *p++; 1375 dmsg->b_rptr = p; 1376 } 1377 } 1378 } 1379 1380 if (extra) { /* the KwKwK case again */ 1381 *wptr++ = ofinchar; 1382 } 1383 1384 /* 1385 * If not first code in a packet, and 1386 * if not out of code space, then allocate a new code. 1387 * 1388 * Keep the hash table correct so it can be used 1389 * with uncompressed packets. 1390 */ 1391 if (oldcode != CLEAR && max_ent < db->maxmaxcode) { 1392 struct bsd_dict *dictp2; 1393 uint32_t fcode; 1394 int hval; 1395 int disp; 1396 1397 fcode = BSD_KEY(oldcode, finchar); 1398 hval = BSD_HASH(oldcode, finchar, db->hshift); 1399 1400 dictp = &db->dict[hval]; 1401 1402 /* 1403 * look for a free hash table entry 1404 */ 1405 if (dictp->codem1 < max_ent) { 1406 disp = (hval == 0) ? 1 : hval; 1407 1408 do { 1409 hval += disp; 1410 1411 if (hval >= db->hsize) { 1412 hval -= db->hsize; 1413 if (hval >= db->hsize) { 1414 freemsg(cmsg); 1415 freemsg(mret); 1416 if (db->flags & 1417 DS_DEBUG) { 1418 cmn_err(CE_CONT, "bsd_decomp%d: internal error\n", 1419 db->unit); 1420 } 1421 return 1422 (DECOMP_FATALERROR); 1423 } 1424 } 1425 1426 dictp = &db->dict[hval]; 1427 1428 } while (dictp->codem1 < max_ent); 1429 } 1430 1431 /* 1432 * Invalidate previous hash table entry 1433 * assigned this code, and then take it over 1434 */ 1435 dictp2 = &db->dict[max_ent+1]; 1436 1437 if (db->dict[dictp2->cptr].codem1 == max_ent) { 1438 db->dict[dictp2->cptr].codem1 = BADCODEM1; 1439 } 1440 1441 dictp2->cptr = (ushort_t)hval; 1442 dictp->codem1 = max_ent; 1443 dictp->f.fcode = fcode; 1444 1445 db->max_ent = ++max_ent; 1446 db->lens[max_ent] = db->lens[oldcode]+1; 1447 1448 /* 1449 * Expand code size if needed 1450 */ 1451 if (max_ent >= MAXCODE(n_bits) && 1452 max_ent < db->maxmaxcode) { 1453 1454 db->n_bits = ++n_bits; 1455 tgtbitno = 32-n_bits; 1456 } 1457 } 1458 1459 oldcode = incode; 1460 } 1461 1462 dlen = wptr-dmsg->b_wptr; 1463 outlen += dlen; 1464 db->in_count += dlen; 1465 dmsg->b_wptr = wptr; 1466 db->bytes_out += ilen; 1467 1468 /* 1469 * Keep the checkpoint right so that incompressible packets 1470 * clear the dictionary at the right times. 1471 */ 1472 if (bsd_check(db) && (db->flags & DS_DEBUG)) { 1473 cmn_err(CE_CONT, 1474 "bsd_decomp%d: peer should have cleared dictionary\n", 1475 db->unit); 1476 } 1477 1478 ++db->comp_count; 1479 db->comp_bytes += ilen + BSD_OVHD; 1480 ++db->uncomp_count; 1481 db->uncomp_bytes += outlen; 1482 1483 *dmpp = mret; 1484 1485 return (DECOMP_OK); 1486 } 1487 1488 /* ARGSUSED */ 1489 static int 1490 bsd_set_effort(void *xarg, void *rarg, int effortlevel) 1491 { 1492 #ifdef DEBUG 1493 struct bsd_db *xdb = (struct bsd_db *)xarg; 1494 struct bsd_db *rdb = (struct bsd_db *)rarg; 1495 1496 if (effortlevel == 42 || effortlevel == 2112) { 1497 /* corrupt received data. */ 1498 if (rdb != NULL) { 1499 rdb->flags |= DS_TESTIN; 1500 cmn_err(CE_CONT, "bsd-comp: enabled input testing."); 1501 } 1502 if (effortlevel != 2112) 1503 return (0); 1504 } 1505 if (effortlevel == 2001 || effortlevel == 2112) { 1506 /* corrupt transmitted data. */ 1507 if (xdb != NULL) { 1508 xdb->flags |= DS_TESTOUT; 1509 cmn_err(CE_CONT, "bsd-comp: enabled output testing."); 1510 } 1511 return (0); 1512 } 1513 #endif 1514 return (0); 1515 } 1516 #endif /* DO_BSD_COMPRESS */ 1517
Indexes created Mon Nov 23 18:03:40 UTC 2009
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