1 /* 2 * Copyright (c) 2000 by Sun Microsystems, Inc. 3 * All rights reserved. 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 #include "s_common.h" 65 66 #ifndef _BIG_ENDIAN 67 #define BSD_LITTLE_ENDIAN 68 #endif 69 70 #if DO_BSD_COMPRESS 71 72 /* 73 * PPP "BSD compress" compression 74 * 75 * The differences between this compression and the classic BSD LZW 76 * source are obvious from the requirement that the classic code worked 77 * with files while this handles arbitrarily long streams that 78 * are broken into packets. They are: 79 * 80 * When the code size expands, a block of junk is not emitted by 81 * the compressor and not expected by the decompressor. 82 * 83 * New codes are not necessarily assigned every time an old 84 * code is output by the compressor. This is because a packet 85 * end forces a code to be emitted, but does not imply that a 86 * new sequence has been seen. 87 * 88 * The compression ratio is checked at the first end of a packet 89 * after the appropriate gap. Besides simplifying and speeding 90 * things up, this makes it more likely that the transmitter 91 * and receiver will agree when the dictionary is cleared when 92 * compression is not going well. 93 */ 94 95 /* 96 * A dictionary for doing BSD compress. 97 */ 98 struct bsd_db { 99 int totlen; /* length of this structure */ 100 uint_t hsize; /* size of the hash table */ 101 uint32_t unit; 102 uchar_t hshift; /* used in hash function */ 103 uchar_t n_bits; /* current bits/code */ 104 uchar_t maxbits; 105 uchar_t flags; 106 ushort_t seqno; /* sequence number of next packet */ 107 ushort_t mru; 108 uint_t hdrlen; /* header length to preallocate */ 109 uint_t maxmaxcode; /* largest valid code */ 110 uint_t max_ent; /* largest code in use */ 111 uint_t in_count; /* uncompressed bytes, aged */ 112 uint_t bytes_out; /* compressed bytes, aged */ 113 uint_t ratio; /* recent compression ratio */ 114 uint_t checkpoint; /* when to next check the ratio */ 115 uint_t clear_count; /* times dictionary cleared */ 116 uint_t incomp_count; /* incompressible packets */ 117 uint_t incomp_bytes; /* incompressible bytes */ 118 uint_t uncomp_count; /* uncompressed packets */ 119 uint_t uncomp_bytes; /* uncompressed bytes */ 120 uint_t comp_count; /* compressed packets */ 121 uint_t comp_bytes; /* compressed bytes */ 122 ushort_t *lens; /* array of lengths of codes */ 123 struct bsd_dict { 124 union { /* hash value */ 125 uint32_t fcode; 126 struct { 127 #ifdef BSD_LITTLE_ENDIAN 128 ushort_t prefix; /* preceding code */ 129 uchar_t suffix; /* last character of new code */ 130 uchar_t pad; 131 #else 132 uchar_t pad; 133 uchar_t suffix; /* last character of new code */ 134 ushort_t prefix; /* preceding code */ 135 #endif 136 } hs; 137 } f; 138 ushort_t codem1; /* output of hash table -1 */ 139 ushort_t cptr; /* map code to hash entry */ 140 } dict[1]; 141 }; 142 143 #define BSD_OVHD 2 /* BSD compress overhead/packet */ 144 #define BSD_INIT_BITS BSD_MIN_BITS 145 146 /* db->flags values */ 147 #define DS_DEBUG 0x01 148 #define DS_TESTIN 0x02 149 #define DS_TESTOUT 0x04 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 return (1); 518 } 519 520 /* 521 * bsd_comp_init() 522 */ 523 static int 524 bsd_comp_init(void *state, uchar_t *options, int opt_len, int unit, int hdrlen, 525 int debug) 526 { 527 return (bsd_init((struct bsd_db *)state, options, opt_len, 528 unit, hdrlen, 0, debug, 0)); 529 } 530 531 /* 532 * bsd_decomp_init() 533 */ 534 static int 535 bsd_decomp_init(void *state, uchar_t *options, int opt_len, int unit, 536 int hdrlen, int mru, int debug) 537 { 538 return (bsd_init((struct bsd_db *)state, options, opt_len, 539 unit, hdrlen, mru, debug, 1)); 540 } 541 542 543 /* 544 * bsd_compress() 545 * 546 * compress a packet 547 * One change from the BSD compress command is that when the 548 * code size expands, we do not output a bunch of padding. 549 * 550 * N.B. at present, we ignore the hdrlen specified in the comp_init call. 551 */ 552 static int /* new slen */ 553 bsd_compress(void *state, mblk_t **mretp, mblk_t *mp, int slen, int maxolen) 554 { 555 struct bsd_db *db = (struct bsd_db *)state; 556 int hshift = db->hshift; 557 uint_t max_ent = db->max_ent; 558 uint_t n_bits = db->n_bits; 559 uint_t bitno = 32; 560 uint32_t accm = 0; 561 uint32_t fcode; 562 struct bsd_dict *dictp; 563 uchar_t c; 564 int hval; 565 int disp; 566 int ent; 567 int ilen = slen - (PPP_HDRLEN-1); 568 mblk_t *mret; 569 uchar_t *rptr, *rmax; 570 uchar_t *wptr; 571 uchar_t *cp_end; 572 int olen; 573 mblk_t *m; 574 mblk_t **mnp; 575 #if defined(lint) || defined(_lint) 576 uchar_t hdlcaddr, hdlcctl; 577 #else 578 int hdlcaddr, hdlcctl; 579 #endif 580 581 #define PUTBYTE(v) { \ 582 if (wptr) { \ 583 *wptr++ = (v); \ 584 if (wptr >= cp_end) { \ 585 m->b_wptr = wptr; \ 586 m = m->b_cont; \ 587 if (m) { \ 588 wptr = m->b_wptr; \ 589 cp_end = m->b_datap->db_lim; \ 590 } else { \ 591 wptr = NULL; \ 592 } \ 593 } \ 594 } \ 595 ++olen; \ 596 } 597 598 #define OUTPUT(ent) { \ 599 bitno -= n_bits; \ 600 accm |= ((ent) << bitno); \ 601 do { \ 602 PUTBYTE(accm >> 24); \ 603 accm <<= 8; \ 604 bitno += 8; \ 605 } while (bitno <= 24); \ 606 } 607 608 #define ADJRPTR() { \ 609 if (rptr != NULL) { \ 610 while (rptr >= rmax) { \ 611 if ((mp = mp->b_cont) == NULL) { \ 612 rptr = NULL; \ 613 break; \ 614 } \ 615 rptr = mp->b_rptr; \ 616 rmax = mp->b_wptr; \ 617 } \ 618 } \ 619 } 620 621 #define GETBYTE(v) { \ 622 if (rptr != NULL) { \ 623 (v) = *rptr++; \ 624 } \ 625 } 626 627 if (db->hsize == 0) 628 return (-1); 629 630 /* 631 * First get the protocol and check that we're 632 * interested in this packet. 633 */ 634 *mretp = NULL; 635 rptr = mp->b_rptr; 636 rmax = mp->b_wptr; 637 638 /* We CANNOT do a pullup here; it's not our buffer to toy with. */ 639 ADJRPTR(); 640 GETBYTE(hdlcaddr); 641 ADJRPTR(); 642 GETBYTE(hdlcctl); 643 ADJRPTR(); 644 GETBYTE(ent); 645 ADJRPTR(); 646 647 /* 648 * Per RFC 1977, the protocol field must be compressed using a 649 * PFC-like procedure. Also, all protocols between 0000-3FFF 650 * except the two compression protocols must be LZ compressed. 651 */ 652 if (ent == 0) { 653 GETBYTE(ent); 654 if (rptr == NULL || ent == PPP_COMP || ent == PPP_COMPFRAG) 655 return (0); 656 } else { 657 if (ent > 0x3F) 658 return (0); 659 ilen++; 660 } 661 662 /* 663 * Don't generate compressed packets that are larger than the 664 * source (uncompressed) packet. 665 */ 666 if (maxolen > slen) { 667 maxolen = slen; 668 } 669 if (maxolen < 6) 670 maxolen = 6; 671 672 /* 673 * Allocate enough message blocks to give maxolen total space 674 */ 675 mnp = &mret; 676 for (olen = maxolen; olen > 0; ) { 677 678 m = allocb((olen < 4096? olen: 4096), BPRI_MED); 679 680 *mnp = m; 681 if (m == NULL) { 682 if (mnp == &mret) 683 return (0); 684 /* We allocated some; hope for the best. */ 685 break; 686 } 687 688 mnp = &m->b_cont; 689 olen -= m->b_datap->db_lim - m->b_wptr; 690 } 691 692 *mnp = NULL; 693 694 m = mret; 695 wptr = m->b_wptr; 696 cp_end = m->b_datap->db_lim; 697 698 olen = 0; 699 700 /* 701 * Copy the PPP header over, changing the protocol, 702 * and install the 2-byte sequence number 703 */ 704 *wptr++ = hdlcaddr; 705 *wptr++ = hdlcctl; 706 *wptr++ = PPP_COMP>>8; /* change the protocol */ 707 *wptr++ = PPP_COMP; 708 *wptr++ = db->seqno >> 8; 709 *wptr++ = db->seqno; 710 711 #ifdef DEBUG 712 /* 713 * If testing output, just garbling the sequence here does the 714 * trick. 715 */ 716 if ((db->flags & DS_TESTOUT) && (db->seqno % 100) == 50) 717 wptr[-1] ^= 0xAA; 718 #endif 719 720 ++db->seqno; 721 722 for (;;) { 723 ADJRPTR(); 724 if (rptr == NULL) 725 break; 726 727 GETBYTE(c); 728 729 fcode = BSD_KEY(ent, c); 730 hval = BSD_HASH(ent, c, hshift); 731 732 dictp = &db->dict[hval]; 733 734 /* 735 * Validate and then check the entry 736 */ 737 if (dictp->codem1 >= max_ent) { 738 goto nomatch; 739 } 740 741 if (dictp->f.fcode == fcode) { 742 ent = dictp->codem1+1; 743 744 /* 745 * found (prefix,suffix) 746 */ 747 continue; 748 } 749 750 /* 751 * continue probing until a match or invalid entry 752 */ 753 disp = (hval == 0) ? 1 : hval; 754 755 do { 756 hval += disp; 757 if (hval >= db->hsize) { 758 hval -= db->hsize; 759 if (hval >= db->hsize) { 760 if (db->flags & DS_DEBUG) { 761 cmn_err(CE_CONT, 762 "bsd_comp%d: internal " 763 "error\n", 764 db->unit); 765 } 766 /* Caller will free it all */ 767 return (-1); 768 } 769 } 770 771 dictp = &db->dict[hval]; 772 773 if (dictp->codem1 >= max_ent) { 774 goto nomatch; 775 } 776 } while (dictp->f.fcode != fcode); 777 778 /* 779 * finally found (prefix,suffix) 780 */ 781 ent = dictp->codem1 + 1; 782 783 continue; 784 785 nomatch: 786 /* 787 * output the prefix 788 */ 789 OUTPUT(ent); 790 791 /* 792 * code -> hashtable 793 */ 794 if (max_ent < db->maxmaxcode) { 795 struct bsd_dict *dictp2; 796 797 /* 798 * expand code size if needed 799 */ 800 if (max_ent >= MAXCODE(n_bits)) { 801 db->n_bits = ++n_bits; 802 } 803 804 /* 805 * Invalidate old hash table entry using 806 * this code, and then take it over. 807 */ 808 dictp2 = &db->dict[max_ent+1]; 809 810 if (db->dict[dictp2->cptr].codem1 == max_ent) { 811 db->dict[dictp2->cptr].codem1 = BADCODEM1; 812 } 813 814 dictp2->cptr = (ushort_t)hval; 815 dictp->codem1 = max_ent; 816 dictp->f.fcode = fcode; 817 818 db->max_ent = ++max_ent; 819 } 820 821 ent = c; 822 } 823 824 /* 825 * output the last code 826 */ 827 OUTPUT(ent); 828 829 olen += (32-bitno+7)/8; /* count complete bytes */ 830 831 db->bytes_out += olen; 832 db->in_count += ilen; 833 834 if (bsd_check(db)) { 835 OUTPUT(CLEAR); /* do not count the CLEAR */ 836 } 837 838 /* 839 * Pad dribble bits of last code with ones. 840 * Do not emit a completely useless byte of ones. 841 */ 842 if (bitno != 32) { 843 PUTBYTE((accm | (0xff << (bitno - 8))) >> 24); 844 } 845 846 /* 847 * Increase code size if we would have without the packet 848 * boundary and as the decompressor will. 849 */ 850 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) { 851 db->n_bits++; 852 } 853 854 db->uncomp_bytes += ilen; 855 ++db->uncomp_count; 856 857 if (wptr == NULL || olen + PPP_HDRLEN + BSD_OVHD >= maxolen) { 858 /* 859 * throw away the compressed stuff if it is longer 860 * than uncompressed 861 */ 862 freemsg(mret); 863 864 mret = NULL; 865 866 ++db->incomp_count; 867 db->incomp_bytes += ilen; 868 869 } else { 870 871 m->b_wptr = wptr; 872 if (m->b_cont) { 873 freemsg(m->b_cont); 874 m->b_cont = NULL; 875 } 876 877 ++db->comp_count; 878 db->comp_bytes += olen + BSD_OVHD; 879 } 880 881 *mretp = mret; 882 883 return (olen + PPP_HDRLEN + BSD_OVHD); 884 #undef OUTPUT 885 #undef PUTBYTE 886 } 887 888 889 /* 890 * bsd_incomp() 891 * 892 * Update the "BSD Compress" dictionary on the receiver for 893 * incompressible data by pretending to compress the incoming data. 894 */ 895 static int 896 bsd_incomp(void *state, mblk_t *mp) 897 { 898 struct bsd_db *db = (struct bsd_db *)state; 899 uint_t hshift = db->hshift; 900 uint_t max_ent = db->max_ent; 901 uint_t n_bits = db->n_bits; 902 struct bsd_dict *dictp; 903 uint32_t fcode; 904 uchar_t c; 905 long hval; 906 long disp; 907 int slen; 908 int ilen; 909 uint_t bitno = 7; 910 uchar_t *rptr, *rmax; 911 uint_t ent; 912 913 if (db->hsize == 0) 914 return (-1); 915 916 rptr = mp->b_rptr; 917 rmax = mp->b_wptr; 918 ADJRPTR(); 919 GETBYTE(ent); /* address */ 920 ADJRPTR(); 921 GETBYTE(ent); /* control */ 922 ADJRPTR(); 923 GETBYTE(ent); /* protocol high */ 924 ADJRPTR(); 925 926 /* 927 * Per RFC 1977, the protocol field must be compressed using a 928 * PFC-like procedure. Also, all protocols between 0000-3FFF 929 * except the two compression protocols must be LZ compressed. 930 */ 931 ilen = 1; /* count the protocol as 1 byte */ 932 if (ent == 0) { 933 GETBYTE(ent); 934 if (rptr == NULL || ent == PPP_COMP || ent == PPP_COMPFRAG) 935 return (0); 936 } else { 937 if (ent > 0x3F) 938 return (0); 939 ilen++; 940 } 941 942 db->seqno++; 943 944 for (;;) { 945 946 slen = mp->b_wptr - rptr; 947 if (slen <= 0) { 948 mp = mp->b_cont; 949 if (!mp) { 950 break; 951 } 952 953 rptr = mp->b_rptr; 954 continue; /* skip zero-length buffers */ 955 } 956 957 ilen += slen; 958 959 do { 960 c = *rptr++; 961 962 fcode = BSD_KEY(ent, c); 963 hval = BSD_HASH(ent, c, hshift); 964 965 dictp = &db->dict[hval]; 966 967 /* 968 * validate and then check the entry 969 */ 970 if (dictp->codem1 >= max_ent) { 971 goto nomatch; 972 } 973 974 if (dictp->f.fcode == fcode) { 975 ent = dictp->codem1 + 1; 976 continue; /* found (prefix,suffix) */ 977 } 978 979 /* 980 * continue probing until a match or invalid entry 981 */ 982 disp = (hval == 0) ? 1 : hval; 983 do { 984 hval += disp; 985 if (hval >= db->hsize) { 986 hval -= db->hsize; 987 if (hval >= db->hsize) { 988 if (db->flags & DS_DEBUG) { 989 cmn_err(CE_CONT, 990 "bsd_incomp%d: " 991 "internal error\n", 992 db->unit); 993 } 994 return (-1); 995 } 996 } 997 998 dictp = &db->dict[hval]; 999 if (dictp->codem1 >= max_ent) { 1000 goto nomatch; 1001 } 1002 } while (dictp->f.fcode != fcode); 1003 1004 ent = dictp->codem1+1; 1005 continue; /* finally found (prefix,suffix) */ 1006 1007 nomatch: /* output (count) the prefix */ 1008 bitno += n_bits; 1009 1010 /* 1011 * code -> hashtable 1012 */ 1013 if (max_ent < db->maxmaxcode) { 1014 struct bsd_dict *dictp2; 1015 1016 /* 1017 * expand code size if needed 1018 */ 1019 if (max_ent >= MAXCODE(n_bits)) { 1020 db->n_bits = ++n_bits; 1021 } 1022 1023 /* 1024 * Invalidate previous hash table entry 1025 * assigned this code, and then take it over. 1026 */ 1027 dictp2 = &db->dict[max_ent+1]; 1028 if (db->dict[dictp2->cptr].codem1 == max_ent) { 1029 db->dict[dictp2->cptr].codem1 = 1030 BADCODEM1; 1031 } 1032 1033 dictp2->cptr = (ushort_t)hval; 1034 dictp->codem1 = max_ent; 1035 dictp->f.fcode = fcode; 1036 1037 db->max_ent = ++max_ent; 1038 db->lens[max_ent] = db->lens[ent]+1; 1039 } 1040 1041 ent = c; 1042 } while (--slen != 0); 1043 } 1044 1045 bitno += n_bits; /* output (count) the last code */ 1046 1047 db->bytes_out += bitno/8; 1048 db->in_count += ilen; 1049 1050 (void) bsd_check(db); 1051 1052 ++db->incomp_count; 1053 db->incomp_bytes += ilen; 1054 ++db->uncomp_count; 1055 db->uncomp_bytes += ilen; 1056 1057 /* 1058 * Increase code size if we would have without the packet 1059 * boundary and as the decompressor will. 1060 */ 1061 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) { 1062 db->n_bits++; 1063 } 1064 return (0); 1065 #undef ADJRPTR 1066 } 1067 1068 1069 /* 1070 * bsd_decompress() 1071 * 1072 * Decompress "BSD Compress" 1073 * 1074 * Because of patent problems, we return DECOMP_ERROR for errors 1075 * found by inspecting the input data and for system problems, but 1076 * DECOMP_FATALERROR for any errors which could possibly be said to 1077 * be being detected "after" decompression. For DECOMP_ERROR, 1078 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be 1079 * infringing a patent of Motorola's if we do, so we take CCP down 1080 * instead. 1081 * 1082 * Given that the frame has the correct sequence number and a good FCS, 1083 * errors such as invalid codes in the input most likely indicate a 1084 * bug, so we return DECOMP_FATALERROR for them in order to turn off 1085 * compression, even though they are detected by inspecting the input. 1086 */ 1087 static int 1088 bsd_decompress(void *state, mblk_t **dmpp) 1089 { 1090 mblk_t *cmsg = *dmpp, *mnext; 1091 struct bsd_db *db = (struct bsd_db *)state; 1092 uint_t max_ent = db->max_ent; 1093 uint32_t accm = 0; 1094 uint_t bitno = 32; /* 1st valid bit in accm */ 1095 uint_t n_bits = db->n_bits; 1096 uint_t tgtbitno = 32 - n_bits; /* bitno when we have a code */ 1097 struct bsd_dict *dictp; 1098 int explen; 1099 int seq; 1100 uint_t incode; 1101 uint_t oldcode; 1102 uint_t finchar = 0, ofinchar; 1103 uchar_t *p; 1104 uchar_t *rptr, *rmax; 1105 uchar_t *wptr, *prepos; 1106 mblk_t *dmsg; 1107 mblk_t *mret; 1108 int ilen; 1109 int dlen; 1110 int codelen; 1111 int extra; 1112 int decode_proto; 1113 int blockctr; 1114 int outlen; 1115 #if defined(lint) || defined(_lint) 1116 uchar_t adrs, ctrl; 1117 #else 1118 int adrs, ctrl; 1119 #endif 1120 1121 /* Note: spppcomp already did a pullup to fix the first buffer. */ 1122 *dmpp = NULL; 1123 rptr = cmsg->b_rptr; 1124 rmax = cmsg->b_wptr; 1125 ilen = 0; 1126 1127 /* 1128 * Note that we free as we go. If we fail to decompress, 1129 * there's nothing good that the caller can do. 1130 */ 1131 #define ADJRPTR() \ 1132 while (rptr >= rmax) { \ 1133 mnext = cmsg->b_cont; \ 1134 freeb(cmsg); \ 1135 if ((cmsg = mnext) == NULL) { \ 1136 rptr = NULL; \ 1137 break; \ 1138 } \ 1139 rptr = cmsg->b_rptr; \ 1140 rmax = cmsg->b_wptr; \ 1141 ilen += rmax-rptr; \ 1142 } 1143 1144 /* 1145 * Save the address/control from the PPP header 1146 * and then get the sequence number. 1147 */ 1148 adrs = rptr[0]; 1149 ctrl = rptr[1]; 1150 rptr += 4; 1151 ADJRPTR(); 1152 seq = rptr == NULL ? 0 : (*rptr++ << 8); 1153 ADJRPTR(); 1154 if (rptr == NULL) { 1155 if (db->flags & DS_DEBUG) { 1156 cmn_err(CE_CONT, "bsd_decomp%d: bad buffer\n", 1157 db->unit); 1158 } 1159 return (DECOMP_ERROR); 1160 } 1161 seq |= *rptr++; 1162 1163 #ifdef DEBUG 1164 /* 1165 * If testing input, just pretending the sequence is bad here 1166 * does the trick. 1167 */ 1168 if ((db->flags & DS_TESTIN) && (db->seqno % 300) == 101) 1169 seq ^= 0x55; 1170 #endif 1171 1172 /* 1173 * Check the sequence number and give up if it is not what we expect. 1174 */ 1175 if (db->hsize == 0 || seq != db->seqno++) { 1176 freemsg(cmsg); 1177 if (db->flags & DS_DEBUG) { 1178 cmn_err(CE_CONT, "bsd_decomp%d: bad sequence # %d, " 1179 "expected %d\n", db->unit, seq, db->seqno - 1); 1180 } 1181 1182 return (DECOMP_ERROR); 1183 } 1184 1185 /* 1186 * Allocate one message block to start with. 1187 */ 1188 if ((dmsg = allocb(DECOMP_CHUNK + db->hdrlen, BPRI_MED)) == NULL) { 1189 freemsg(cmsg); 1190 if (db->flags & DS_DEBUG) { 1191 cmn_err(CE_CONT, 1192 "bsd_decomp%d: can't allocate first buffer\n", 1193 db->unit); 1194 } 1195 return (DECOMP_ERROR); 1196 } 1197 1198 /* 1199 * Avoid an error that might cause us to allocate all available memory. 1200 * Enforce a maximum number of blocks to allocate for message. We add 1201 * a fudge factor of 5 extra blocks, in order to avoid unnecessary 1202 * DECOMP_ERROR when the code size is small (9). 1203 */ 1204 blockctr = ((db->mru + 32 + DECOMP_CHUNK - 1) / DECOMP_CHUNK) + 5; 1205 1206 mret = dmsg; 1207 dmsg->b_wptr += db->hdrlen; 1208 dmsg->b_rptr = wptr = dmsg->b_wptr; 1209 1210 /* 1211 * Insert PPP header. This shouldn't be needed! 1212 */ 1213 *wptr++ = adrs; 1214 *wptr++ = ctrl; 1215 prepos = wptr; 1216 *wptr++ = 0; 1217 dmsg->b_wptr = wptr; 1218 1219 explen = dmsg->b_datap->db_lim - wptr; 1220 oldcode = CLEAR; 1221 ilen = rmax-rptr; 1222 1223 outlen = 0; 1224 decode_proto = 1; 1225 for (;;) { 1226 ADJRPTR(); 1227 if (rptr == NULL) 1228 break; 1229 1230 /* 1231 * Accumulate bytes until we have a complete code. 1232 * Then get the next code, relying on the 32-bit, 1233 * unsigned accm to mask the result. 1234 */ 1235 bitno -= 8; 1236 1237 accm |= *rptr++ << bitno; 1238 1239 if (tgtbitno < bitno) { 1240 continue; 1241 } 1242 1243 incode = accm >> tgtbitno; 1244 accm <<= n_bits; 1245 bitno += n_bits; 1246 1247 if (incode == CLEAR) { 1248 1249 /* 1250 * The dictionary must only be cleared at 1251 * the end of a packet. But there could be an 1252 * empty message block at the end. 1253 */ 1254 ADJRPTR(); 1255 if (rptr != NULL) { 1256 freemsg(mret); 1257 freemsg(cmsg); 1258 if (db->flags & DS_DEBUG) { 1259 cmn_err(CE_CONT, 1260 "bsd_decomp%d: bad CLEAR\n", 1261 db->unit); 1262 } 1263 1264 return (DECOMP_FATALERROR); 1265 } 1266 1267 bsd_clear(db); 1268 /* Have to keep cleared state variables! */ 1269 outlen += wptr-dmsg->b_wptr; 1270 dmsg->b_wptr = wptr; 1271 db->comp_bytes += ilen; 1272 ilen = 0; 1273 break; 1274 } 1275 1276 /* 1277 * Special case for KwKwK string 1278 */ 1279 ofinchar = finchar; 1280 if (incode > max_ent) { 1281 if (incode > max_ent + 2 || 1282 incode > db->maxmaxcode || 1283 oldcode == CLEAR) { 1284 freemsg(cmsg); 1285 freemsg(mret); 1286 1287 /* probably a bug if we get here */ 1288 if (db->flags & DS_DEBUG) { 1289 cmn_err(CE_CONT, 1290 "bsd_decomp%d: bad code 0x%x " 1291 "oldcode=0x%x ", db->unit, incode, 1292 oldcode); 1293 } 1294 1295 return (DECOMP_FATALERROR); 1296 } 1297 finchar = oldcode; 1298 extra = 1; 1299 } else { 1300 finchar = incode; 1301 extra = 0; 1302 } 1303 codelen = db->lens[finchar]; 1304 1305 /* 1306 * Decode this code and install it in the decompressed buffer 1307 */ 1308 explen -= codelen + extra; 1309 if (explen < 0) { 1310 /* 1311 * Allocate another message block 1312 */ 1313 dlen = wptr - dmsg->b_wptr; 1314 outlen += dlen; 1315 db->in_count += dlen; 1316 dmsg->b_wptr = wptr; 1317 dlen = codelen + extra; 1318 1319 if (dlen < DECOMP_CHUNK) { 1320 dlen = DECOMP_CHUNK; 1321 } 1322 1323 if ((--blockctr < 0) || 1324 (dmsg->b_cont = allocb(dlen, BPRI_MED)) == NULL) { 1325 freemsg(cmsg); 1326 freemsg(mret); 1327 if (db->flags & DS_DEBUG) { 1328 cmn_err(CE_CONT, 1329 "bsd_decomp%d: %s output " 1330 "buffers; outlen %d+%d\n", 1331 db->unit, 1332 (blockctr < 0 ? "too many" : 1333 "can't allocate"), 1334 outlen, dlen); 1335 } 1336 return (DECOMP_ERROR); 1337 } 1338 1339 dmsg = dmsg->b_cont; 1340 wptr = dmsg->b_wptr; 1341 explen = dmsg->b_datap->db_lim - wptr - codelen - 1342 extra; 1343 } 1344 1345 p = (wptr += codelen); 1346 1347 while (finchar > LAST) { 1348 dictp = &db->dict[db->dict[finchar].cptr]; 1349 *--p = dictp->f.hs.suffix; 1350 finchar = dictp->f.hs.prefix; 1351 } 1352 1353 *--p = finchar; 1354 1355 if (decode_proto) { 1356 decode_proto = 0; 1357 /* Wow, is *this* ugly! */ 1358 if (!(finchar & 1)) { 1359 if (p == prepos+1) { 1360 bcopy(p, prepos, wptr-p); 1361 wptr--; 1362 explen++; 1363 db->in_count++; 1364 } else { 1365 /* This is safe, but doesn't look it */ 1366 *prepos = *p++; 1367 dmsg->b_rptr = p; 1368 } 1369 } 1370 } 1371 1372 if (extra) { /* the KwKwK case again */ 1373 *wptr++ = ofinchar; 1374 } 1375 1376 /* 1377 * If not first code in a packet, and 1378 * if not out of code space, then allocate a new code. 1379 * 1380 * Keep the hash table correct so it can be used 1381 * with uncompressed packets. 1382 */ 1383 if (oldcode != CLEAR && max_ent < db->maxmaxcode) { 1384 struct bsd_dict *dictp2; 1385 uint32_t fcode; 1386 int hval; 1387 int disp; 1388 1389 fcode = BSD_KEY(oldcode, finchar); 1390 hval = BSD_HASH(oldcode, finchar, db->hshift); 1391 1392 dictp = &db->dict[hval]; 1393 1394 /* 1395 * look for a free hash table entry 1396 */ 1397 if (dictp->codem1 < max_ent) { 1398 disp = (hval == 0) ? 1 : hval; 1399 1400 do { 1401 hval += disp; 1402 1403 if (hval >= db->hsize) { 1404 hval -= db->hsize; 1405 if (hval >= db->hsize) { 1406 freemsg(cmsg); 1407 freemsg(mret); 1408 if (db->flags & 1409 DS_DEBUG) { 1410 cmn_err(CE_CONT, "bsd_decomp%d: internal error\n", 1411 db->unit); 1412 } 1413 return 1414 (DECOMP_FATALERROR); 1415 } 1416 } 1417 1418 dictp = &db->dict[hval]; 1419 1420 } while (dictp->codem1 < max_ent); 1421 } 1422 1423 /* 1424 * Invalidate previous hash table entry 1425 * assigned this code, and then take it over 1426 */ 1427 dictp2 = &db->dict[max_ent+1]; 1428 1429 if (db->dict[dictp2->cptr].codem1 == max_ent) { 1430 db->dict[dictp2->cptr].codem1 = BADCODEM1; 1431 } 1432 1433 dictp2->cptr = (ushort_t)hval; 1434 dictp->codem1 = max_ent; 1435 dictp->f.fcode = fcode; 1436 1437 db->max_ent = ++max_ent; 1438 db->lens[max_ent] = db->lens[oldcode]+1; 1439 1440 /* 1441 * Expand code size if needed 1442 */ 1443 if (max_ent >= MAXCODE(n_bits) && 1444 max_ent < db->maxmaxcode) { 1445 1446 db->n_bits = ++n_bits; 1447 tgtbitno = 32-n_bits; 1448 } 1449 } 1450 1451 oldcode = incode; 1452 } 1453 1454 dlen = wptr-dmsg->b_wptr; 1455 outlen += dlen; 1456 db->in_count += dlen; 1457 dmsg->b_wptr = wptr; 1458 db->bytes_out += ilen; 1459 1460 /* 1461 * Keep the checkpoint right so that incompressible packets 1462 * clear the dictionary at the right times. 1463 */ 1464 if (bsd_check(db) && (db->flags & DS_DEBUG)) { 1465 cmn_err(CE_CONT, 1466 "bsd_decomp%d: peer should have cleared dictionary\n", 1467 db->unit); 1468 } 1469 1470 ++db->comp_count; 1471 db->comp_bytes += ilen + BSD_OVHD; 1472 ++db->uncomp_count; 1473 db->uncomp_bytes += outlen; 1474 1475 *dmpp = mret; 1476 1477 return (DECOMP_OK); 1478 } 1479 1480 /* ARGSUSED */ 1481 static int 1482 bsd_set_effort(void *xarg, void *rarg, int effortlevel) 1483 { 1484 #ifdef DEBUG 1485 struct bsd_db *xdb = (struct bsd_db *)xarg; 1486 struct bsd_db *rdb = (struct bsd_db *)rarg; 1487 1488 if (effortlevel == 42 || effortlevel == 2112) { 1489 /* corrupt received data. */ 1490 if (rdb != NULL) { 1491 rdb->flags |= DS_TESTIN; 1492 cmn_err(CE_CONT, "bsd-comp: enabled input testing."); 1493 } 1494 if (effortlevel != 2112) 1495 return (0); 1496 } 1497 if (effortlevel == 2001 || effortlevel == 2112) { 1498 /* corrupt transmitted data. */ 1499 if (xdb != NULL) { 1500 xdb->flags |= DS_TESTOUT; 1501 cmn_err(CE_CONT, "bsd-comp: enabled output testing."); 1502 } 1503 return (0); 1504 } 1505 #endif 1506 return (0); 1507 } 1508 #endif /* DO_BSD_COMPRESS */ 1509