1 /* $NetBSD: ppp-deflate.c,v 1.25 2025/11/24 08:04:28 nia Exp $ */ 2 /* Id: ppp-deflate.c,v 1.5 1997/03/04 03:33:28 paulus Exp */ 3 4 /* 5 * ppp_deflate.c - interface the zlib procedures for Deflate compression 6 * and decompression (as used by gzip) to the PPP code. 7 * This version is for use with mbufs on BSD-derived systems. 8 * 9 * Copyright (c) 1989-2002 Paul Mackerras. All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in 20 * the documentation and/or other materials provided with the 21 * distribution. 22 * 23 * 3. The name(s) of the authors of this software must not be used to 24 * endorse or promote products derived from this software without 25 * prior written permission. 26 * 27 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO 28 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 29 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY 30 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 31 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 32 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 33 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: ppp-deflate.c,v 1.25 2025/11/24 08:04:28 nia Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/mbuf.h> 42 #include <sys/module.h> 43 #include <net/if.h> 44 #include <net/ppp_defs.h> 45 #include <net/if_ppp.h> 46 #include <net/zlib.h> 47 48 #define PACKETPTR struct mbuf * 49 #include <net/ppp-comp.h> 50 51 #if DO_DEFLATE 52 53 #define DEFLATE_DEBUG 1 54 55 /* 56 * State for a Deflate (de)compressor. 57 */ 58 struct deflate_state { 59 int seqno; 60 int w_size; 61 int unit; 62 int hdrlen; 63 int mru; 64 int debug; 65 z_stream strm; 66 struct compstat stats; 67 }; 68 69 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */ 70 71 static void *zalloc(void *, u_int items, u_int size); 72 static void zfree(void *, void *ptr); 73 static void *z_comp_alloc(u_char *options, int opt_len); 74 static void *z_decomp_alloc(u_char *options, int opt_len); 75 static void z_comp_free(void *state); 76 static void z_decomp_free(void *state); 77 static int z_comp_init(void *state, u_char *options, int opt_len, 78 int unit, int hdrlen, int debug); 79 static int z_decomp_init(void *state, u_char *options, int opt_len, 80 int unit, int hdrlen, int mru, int debug); 81 static int z_compress(void *state, struct mbuf **mret, 82 struct mbuf *mp, int slen, int maxolen); 83 static void z_incomp(void *state, struct mbuf *dmsg); 84 static int z_decompress(void *state, struct mbuf *cmp, 85 struct mbuf **dmpp); 86 static void z_comp_reset(void *state); 87 static void z_decomp_reset(void *state); 88 static void z_comp_stats(void *state, struct compstat *stats); 89 90 /* 91 * Procedures exported to if_ppp.c. 92 */ 93 static struct compressor ppp_deflate[2] = { { 94 .compress_proto = CI_DEFLATE, 95 .comp_alloc = z_comp_alloc, 96 .comp_free = z_comp_free, 97 .comp_init = z_comp_init, 98 .comp_reset = z_comp_reset, 99 .compress = z_compress, 100 .comp_stat = z_comp_stats, 101 .decomp_alloc = z_decomp_alloc, 102 .decomp_free = z_decomp_free, 103 .decomp_init = z_decomp_init, 104 .decomp_reset = z_decomp_reset, 105 .decompress = z_decompress, 106 .incomp = z_incomp, 107 .decomp_stat = z_comp_stats, 108 }, 109 { 110 .compress_proto = CI_DEFLATE_DRAFT, 111 .comp_alloc = z_comp_alloc, 112 .comp_free = z_comp_free, 113 .comp_init = z_comp_init, 114 .comp_reset = z_comp_reset, 115 .compress = z_compress, 116 .comp_stat = z_comp_stats, 117 .decomp_alloc = z_decomp_alloc, 118 .decomp_free = z_decomp_free, 119 .decomp_init = z_decomp_init, 120 .decomp_reset = z_decomp_reset, 121 .decompress = z_decompress, 122 .incomp = z_incomp, 123 .decomp_stat = z_comp_stats, 124 } }; 125 /* 126 * Space allocation and freeing routines for use by zlib routines. 127 */ 128 void * 129 zalloc(void *notused, u_int items, u_int size) 130 { 131 void *ptr; 132 133 ptr = malloc(items * size, M_DEVBUF, M_NOWAIT); 134 return ptr; 135 } 136 137 void 138 zfree(void *notused, void *ptr) 139 { 140 free(ptr, M_DEVBUF); 141 } 142 143 /* 144 * Allocate space for a compressor. 145 */ 146 static void * 147 z_comp_alloc(u_char *options, int opt_len) 148 { 149 struct deflate_state *state; 150 int w_size; 151 152 if (opt_len != CILEN_DEFLATE 153 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) 154 || options[1] != CILEN_DEFLATE 155 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL 156 || options[3] != DEFLATE_CHK_SEQUENCE) 157 return NULL; 158 w_size = DEFLATE_SIZE(options[2]); 159 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) 160 return NULL; 161 162 state = malloc(sizeof(struct deflate_state), M_DEVBUF, M_NOWAIT); 163 if (state == NULL) 164 return NULL; 165 166 state->strm.next_in = NULL; 167 state->strm.zalloc = zalloc; 168 state->strm.zfree = zfree; 169 if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL, 170 -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) { 171 free(state, M_DEVBUF); 172 return NULL; 173 } 174 175 state->w_size = w_size; 176 memset(&state->stats, 0, sizeof(state->stats)); 177 return (void *) state; 178 } 179 180 static void 181 z_comp_free(void *arg) 182 { 183 struct deflate_state *state = (struct deflate_state *) arg; 184 185 deflateEnd(&state->strm); 186 free(state, M_DEVBUF); 187 } 188 189 static int 190 z_comp_init(void *arg, u_char *options, int opt_len, int unit, int hdrlen, 191 int debug) 192 { 193 struct deflate_state *state = (struct deflate_state *) arg; 194 195 if (opt_len < CILEN_DEFLATE 196 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) 197 || options[1] != CILEN_DEFLATE 198 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL 199 || DEFLATE_SIZE(options[2]) != state->w_size 200 || options[3] != DEFLATE_CHK_SEQUENCE) 201 return 0; 202 203 state->seqno = 0; 204 state->unit = unit; 205 state->hdrlen = hdrlen; 206 state->debug = debug; 207 208 deflateReset(&state->strm); 209 210 return 1; 211 } 212 213 static void 214 z_comp_reset(void *arg) 215 { 216 struct deflate_state *state = (struct deflate_state *) arg; 217 218 state->seqno = 0; 219 deflateReset(&state->strm); 220 } 221 222 int 223 z_compress(void *arg, 224 struct mbuf **mret /* compressed packet (out) */, 225 struct mbuf *mp /* uncompressed packet (in) */, 226 int orig_len, int maxolen) 227 { 228 struct deflate_state *state = (struct deflate_state *) arg; 229 u_char *rptr, *wptr; 230 int proto, olen, wspace, r, flush; 231 struct mbuf *m; 232 233 /* 234 * Check that the protocol is in the range we handle. 235 */ 236 rptr = mtod(mp, u_char *); 237 proto = PPP_PROTOCOL(rptr); 238 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) { 239 *mret = NULL; 240 return orig_len; 241 } 242 243 /* Allocate one mbuf initially. */ 244 if (maxolen > orig_len) 245 maxolen = orig_len; 246 MGET(m, M_DONTWAIT, MT_DATA); 247 *mret = m; 248 if (m != NULL) { 249 m->m_len = 0; 250 if (maxolen + state->hdrlen > MLEN) 251 MCLGET(m, M_DONTWAIT); 252 wspace = M_TRAILINGSPACE(m); 253 if (state->hdrlen + PPP_HDRLEN + 2 < wspace) { 254 m->m_data += state->hdrlen; 255 wspace -= state->hdrlen; 256 } 257 wptr = mtod(m, u_char *); 258 259 /* 260 * Copy over the PPP header and store the 2-byte sequence number. 261 */ 262 wptr[0] = PPP_ADDRESS(rptr); 263 wptr[1] = PPP_CONTROL(rptr); 264 wptr[2] = PPP_COMP >> 8; 265 wptr[3] = PPP_COMP; 266 wptr += PPP_HDRLEN; 267 wptr[0] = state->seqno >> 8; 268 wptr[1] = state->seqno; 269 wptr += 2; 270 state->strm.next_out = wptr; 271 state->strm.avail_out = wspace - (PPP_HDRLEN + 2); 272 } else { 273 state->strm.next_out = NULL; 274 state->strm.avail_out = 1000000; 275 wptr = NULL; 276 wspace = 0; 277 } 278 ++state->seqno; 279 280 rptr += (proto > 0xff)? 2: 3; /* skip 1st proto byte if 0 */ 281 state->strm.next_in = rptr; 282 state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr; 283 mp = mp->m_next; 284 flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH; 285 olen = 0; 286 for (;;) { 287 r = deflate(&state->strm, flush); 288 if (r != Z_OK) { 289 printf("z_compress: deflate returned %d (%s)\n", 290 r, (state->strm.msg? state->strm.msg: "")); 291 break; 292 } 293 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0) 294 break; /* all done */ 295 if (state->strm.avail_in == 0 && mp != NULL) { 296 state->strm.next_in = mtod(mp, u_char *); 297 state->strm.avail_in = mp->m_len; 298 mp = mp->m_next; 299 if (mp == NULL) 300 flush = Z_PACKET_FLUSH; 301 } 302 if (state->strm.avail_out == 0) { 303 if (m != NULL) { 304 m->m_len = wspace; 305 olen += wspace; 306 MGET(m->m_next, M_DONTWAIT, MT_DATA); 307 m = m->m_next; 308 if (m != NULL) { 309 m->m_len = 0; 310 if (maxolen - olen > MLEN) 311 MCLGET(m, M_DONTWAIT); 312 state->strm.next_out = mtod(m, u_char *); 313 state->strm.avail_out = wspace = M_TRAILINGSPACE(m); 314 } 315 } 316 if (m == NULL) { 317 state->strm.next_out = NULL; 318 state->strm.avail_out = 1000000; 319 } 320 } 321 } 322 if (m != NULL) 323 olen += (m->m_len = wspace - state->strm.avail_out); 324 325 /* 326 * See if we managed to reduce the size of the packet. 327 */ 328 if (m != NULL && olen < orig_len) { 329 state->stats.comp_bytes += olen; 330 state->stats.comp_packets++; 331 } else { 332 m_freem(*mret); 333 *mret = NULL; 334 state->stats.inc_bytes += orig_len; 335 state->stats.inc_packets++; 336 olen = orig_len; 337 } 338 state->stats.unc_bytes += orig_len; 339 state->stats.unc_packets++; 340 341 return olen; 342 } 343 344 static void 345 z_comp_stats(void *arg, struct compstat *stats) 346 { 347 struct deflate_state *state = (struct deflate_state *) arg; 348 u_int out; 349 350 *stats = state->stats; 351 stats->ratio = stats->unc_bytes; 352 out = stats->comp_bytes + stats->inc_bytes; 353 if (stats->ratio <= 0x7ffffff) 354 stats->ratio <<= 8; 355 else 356 out >>= 8; 357 if (out != 0) 358 stats->ratio /= out; 359 } 360 361 /* 362 * Allocate space for a decompressor. 363 */ 364 static void * 365 z_decomp_alloc(u_char *options, int opt_len) 366 { 367 struct deflate_state *state; 368 int w_size; 369 370 if (opt_len != CILEN_DEFLATE 371 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) 372 || options[1] != CILEN_DEFLATE 373 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL 374 || options[3] != DEFLATE_CHK_SEQUENCE) 375 return NULL; 376 w_size = DEFLATE_SIZE(options[2]); 377 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) 378 return NULL; 379 380 state = malloc(sizeof(struct deflate_state), M_DEVBUF, M_NOWAIT); 381 if (state == NULL) 382 return NULL; 383 384 state->strm.next_out = NULL; 385 state->strm.zalloc = zalloc; 386 state->strm.zfree = zfree; 387 if (inflateInit2(&state->strm, -w_size) != Z_OK) { 388 free(state, M_DEVBUF); 389 return NULL; 390 } 391 392 state->w_size = w_size; 393 memset(&state->stats, 0, sizeof(state->stats)); 394 return (void *) state; 395 } 396 397 static void 398 z_decomp_free(void *arg) 399 { 400 struct deflate_state *state = (struct deflate_state *) arg; 401 402 inflateEnd(&state->strm); 403 free(state, M_DEVBUF); 404 } 405 406 static int 407 z_decomp_init(void *arg, u_char *options, int opt_len, int unit, int hdrlen, 408 int mru, int debug) 409 { 410 struct deflate_state *state = (struct deflate_state *) arg; 411 412 if (opt_len < CILEN_DEFLATE 413 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) 414 || options[1] != CILEN_DEFLATE 415 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL 416 || DEFLATE_SIZE(options[2]) != state->w_size 417 || options[3] != DEFLATE_CHK_SEQUENCE) 418 return 0; 419 420 state->seqno = 0; 421 state->unit = unit; 422 state->hdrlen = hdrlen; 423 state->debug = debug; 424 state->mru = mru; 425 426 inflateReset(&state->strm); 427 428 return 1; 429 } 430 431 static void 432 z_decomp_reset(void *arg) 433 { 434 struct deflate_state *state = (struct deflate_state *) arg; 435 436 state->seqno = 0; 437 inflateReset(&state->strm); 438 } 439 440 /* 441 * Decompress a Deflate-compressed packet. 442 * 443 * Because of patent problems, we return DECOMP_ERROR for errors 444 * found by inspecting the input data and for system problems, but 445 * DECOMP_FATALERROR for any errors which could possibly be said to 446 * be being detected "after" decompression. For DECOMP_ERROR, 447 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be 448 * infringing a patent of Motorola's if we do, so we take CCP down 449 * instead. 450 * 451 * Given that the frame has the correct sequence number and a good FCS, 452 * errors such as invalid codes in the input most likely indicate a 453 * bug, so we return DECOMP_FATALERROR for them in order to turn off 454 * compression, even though they are detected by inspecting the input. 455 */ 456 int 457 z_decompress(void *arg, struct mbuf *mi, struct mbuf **mop) 458 { 459 struct deflate_state *state = (struct deflate_state *) arg; 460 struct mbuf *mo, *mo_head; 461 u_char *rptr, *wptr; 462 int rlen, olen, ospace; 463 int seq, i, flush, r, decode_proto; 464 u_char hdr[PPP_HDRLEN + DEFLATE_OVHD]; 465 466 *mop = NULL; 467 rptr = mtod(mi, u_char *); 468 rlen = mi->m_len; 469 for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) { 470 while (rlen <= 0) { 471 mi = mi->m_next; 472 if (mi == NULL) 473 return DECOMP_ERROR; 474 rptr = mtod(mi, u_char *); 475 rlen = mi->m_len; 476 } 477 hdr[i] = *rptr++; 478 --rlen; 479 } 480 481 /* Check the sequence number. */ 482 seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1]; 483 if (seq != state->seqno) { 484 if (state->debug) 485 printf("z_decompress%d: bad seq # %d, expected %d\n", 486 state->unit, seq, state->seqno); 487 return DECOMP_ERROR; 488 } 489 ++state->seqno; 490 491 /* Allocate an output mbuf. */ 492 MGETHDR(mo, M_DONTWAIT, MT_DATA); 493 if (mo == NULL) 494 return DECOMP_ERROR; 495 mo_head = mo; 496 mo->m_len = 0; 497 mo->m_next = NULL; 498 MCLGET(mo, M_DONTWAIT); 499 ospace = M_TRAILINGSPACE(mo); 500 if (state->hdrlen + PPP_HDRLEN < ospace) { 501 mo->m_data += state->hdrlen; 502 ospace -= state->hdrlen; 503 } 504 505 /* 506 * Fill in the first part of the PPP header. The protocol field 507 * comes from the decompressed data. 508 */ 509 wptr = mtod(mo, u_char *); 510 wptr[0] = PPP_ADDRESS(hdr); 511 wptr[1] = PPP_CONTROL(hdr); 512 wptr[2] = 0; 513 514 /* 515 * Set up to call inflate. We set avail_out to 1 initially so we can 516 * look at the first byte of the output and decide whether we have 517 * a 1-byte or 2-byte protocol field. 518 */ 519 state->strm.next_in = rptr; 520 state->strm.avail_in = rlen; 521 mi = mi->m_next; 522 flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH; 523 rlen += PPP_HDRLEN + DEFLATE_OVHD; 524 state->strm.next_out = wptr + 3; 525 state->strm.avail_out = 1; 526 decode_proto = 1; 527 olen = 0; 528 529 /* 530 * Call inflate, supplying more input or output as needed. 531 */ 532 for (;;) { 533 r = inflate(&state->strm, flush); 534 if (r != Z_OK) { 535 #if !DEFLATE_DEBUG 536 if (state->debug) 537 #endif 538 printf("z_decompress%d: inflate returned %d (%s)\n", 539 state->unit, r, (state->strm.msg? state->strm.msg: "")); 540 m_freem(mo_head); 541 return DECOMP_FATALERROR; 542 } 543 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0) 544 break; /* all done */ 545 if (state->strm.avail_in == 0 && mi != NULL) { 546 state->strm.next_in = mtod(mi, u_char *); 547 state->strm.avail_in = mi->m_len; 548 rlen += mi->m_len; 549 mi = mi->m_next; 550 if (mi == NULL) 551 flush = Z_PACKET_FLUSH; 552 } 553 if (state->strm.avail_out == 0) { 554 if (decode_proto) { 555 state->strm.avail_out = ospace - PPP_HDRLEN; 556 if ((wptr[3] & 1) == 0) { 557 /* 2-byte protocol field */ 558 wptr[2] = wptr[3]; 559 --state->strm.next_out; 560 ++state->strm.avail_out; 561 --olen; 562 } 563 decode_proto = 0; 564 } else { 565 mo->m_len = ospace; 566 olen += ospace; 567 MGET(mo->m_next, M_DONTWAIT, MT_DATA); 568 mo = mo->m_next; 569 if (mo == NULL) { 570 m_freem(mo_head); 571 return DECOMP_ERROR; 572 } 573 MCLGET(mo, M_DONTWAIT); 574 state->strm.next_out = mtod(mo, u_char *); 575 state->strm.avail_out = ospace = M_TRAILINGSPACE(mo); 576 } 577 } 578 } 579 if (decode_proto) { 580 m_freem(mo_head); 581 return DECOMP_ERROR; 582 } 583 olen += (mo->m_len = ospace - state->strm.avail_out); 584 #if DEFLATE_DEBUG 585 if (olen > state->mru + PPP_HDRLEN) 586 printf("ppp_deflate%d: exceeded mru (%d > %d)\n", 587 state->unit, olen, state->mru + PPP_HDRLEN); 588 #endif 589 590 state->stats.unc_bytes += olen; 591 state->stats.unc_packets++; 592 state->stats.comp_bytes += rlen; 593 state->stats.comp_packets++; 594 595 *mop = mo_head; 596 return DECOMP_OK; 597 } 598 599 /* 600 * Incompressible data has arrived - add it to the history. 601 */ 602 static void 603 z_incomp(void *arg, struct mbuf *mi) 604 { 605 struct deflate_state *state = (struct deflate_state *) arg; 606 u_char *rptr; 607 int rlen, proto, r; 608 609 /* 610 * Check that the protocol is one we handle. 611 */ 612 rptr = mtod(mi, u_char *); 613 proto = PPP_PROTOCOL(rptr); 614 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) 615 return; 616 617 ++state->seqno; 618 619 /* 620 * Iterate through the mbufs, adding the characters in them 621 * to the decompressor's history. For the first mbuf, we start 622 * at the either the 1st or 2nd byte of the protocol field, 623 * depending on whether the protocol value is compressible. 624 */ 625 rlen = mi->m_len; 626 state->strm.next_in = rptr + 3; 627 state->strm.avail_in = rlen - 3; 628 if (proto > 0xff) { 629 --state->strm.next_in; 630 ++state->strm.avail_in; 631 } 632 for (;;) { 633 r = inflateIncomp(&state->strm); 634 if (r != Z_OK) { 635 /* gak! */ 636 #if !DEFLATE_DEBUG 637 if (state->debug) 638 #endif 639 printf("z_incomp%d: inflateIncomp returned %d (%s)\n", 640 state->unit, r, (state->strm.msg? state->strm.msg: "")); 641 return; 642 } 643 mi = mi->m_next; 644 if (mi == NULL) 645 break; 646 state->strm.next_in = mtod(mi, u_char *); 647 state->strm.avail_in = mi->m_len; 648 rlen += mi->m_len; 649 } 650 651 /* 652 * Update stats. 653 */ 654 state->stats.inc_bytes += rlen; 655 state->stats.inc_packets++; 656 state->stats.unc_bytes += rlen; 657 state->stats.unc_packets++; 658 } 659 660 MODULE(MODULE_CLASS_MISC, ppp_deflate, "zlib,if_ppp"); 661 662 static int 663 ppp_deflate_modcmd(modcmd_t cmd, void *arg) 664 { 665 666 switch (cmd) { 667 case MODULE_CMD_INIT: 668 return ppp_register_compressor(ppp_deflate, 2); 669 case MODULE_CMD_FINI: 670 return ppp_unregister_compressor(ppp_deflate, 2); 671 case MODULE_CMD_STAT: 672 return 0; 673 default: 674 return ENOTTY; 675 } 676 677 return ENOTTY; 678 } 679 #endif /* DO_DEFLATE */ 680
Indexes created Mon Feb 23 16:20:21 UTC 2026