1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32/* 33 * Routines to compress and uncompess tcp packets (for transmission 34 * over low speed serial lines. 35 * 36 * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989: 37 * - Initial distribution. 38 */ 39 40#include <sys/param.h> 41#include <netinet/in_systm.h> 42#include <netinet/in.h> 43#include <netinet/tcp.h> 44#include <netinet/ip.h> 45#include <sys/socket.h> 46#include <sys/un.h> 47 48#include <stdarg.h> 49#include <stdio.h> 50#include <string.h> 51#include <termios.h> 52 53#include "layer.h" 54#include "defs.h" 55#include "command.h" 56#include "mbuf.h" 57#include "log.h" 58#include "slcompress.h" 59#include "descriptor.h" 60#include "prompt.h" 61#include "timer.h" 62#include "fsm.h" 63#include "throughput.h" 64#include "iplist.h" 65#include "lqr.h" 66#include "hdlc.h" 67#include "ncpaddr.h" 68#include "ipcp.h" 69#include "filter.h" 70#include "lcp.h" 71#include "ccp.h" 72#include "link.h" 73#include "mp.h" 74#ifndef NORADIUS 75#include "radius.h" 76#endif 77#include "ipv6cp.h" 78#include "ncp.h" 79#include "bundle.h" 80 81void 82sl_compress_init(struct slcompress *comp, int max_state) 83{ 84 register u_int i; 85 register struct cstate *tstate = comp->tstate; 86 87 memset(comp, '\0', sizeof *comp); 88 for (i = max_state; i > 0; --i) { 89 tstate[i].cs_id = i; 90 tstate[i].cs_next = &tstate[i - 1]; 91 } 92 tstate[0].cs_next = &tstate[max_state]; 93 tstate[0].cs_id = 0; 94 comp->last_cs = &tstate[0]; 95 comp->last_recv = 255; 96 comp->last_xmit = 255; 97 comp->flags = SLF_TOSS; 98} 99 100 101/* ENCODE encodes a number that is known to be non-zero. ENCODEZ 102 * checks for zero (since zero has to be encoded in the 32-bit, 3 byte 103 * form). 104 */ 105#define ENCODE(n) { \ 106 if ((u_short)(n) >= 256) { \ 107 *cp++ = 0; \ 108 cp[1] = (n); \ 109 cp[0] = (n) >> 8; \ 110 cp += 2; \ 111 } else { \ 112 *cp++ = (n); \ 113 } \ 114} 115#define ENCODEZ(n) { \ 116 if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \ 117 *cp++ = 0; \ 118 cp[1] = (n); \ 119 cp[0] = (n) >> 8; \ 120 cp += 2; \ 121 } else { \ 122 *cp++ = (n); \ 123 } \ 124} 125 126#define DECODEL(f) { \ 127 if (*cp == 0) {\ 128 (f) = htonl(ntohl(f) + ((cp[1] << 8) | cp[2])); \ 129 cp += 3; \ 130 } else { \ 131 (f) = htonl(ntohl(f) + (u_int32_t)*cp++); \ 132 } \ 133} 134 135#define DECODES(f) { \ 136 if (*cp == 0) {\ 137 (f) = htons(ntohs(f) + ((cp[1] << 8) | cp[2])); \ 138 cp += 3; \ 139 } else { \ 140 (f) = htons(ntohs(f) + (u_int32_t)*cp++); \ 141 } \ 142} 143 144#define DECODEU(f) { \ 145 if (*cp == 0) {\ 146 (f) = htons((cp[1] << 8) | cp[2]); \ 147 cp += 3; \ 148 } else { \ 149 (f) = htons((u_int32_t)*cp++); \ 150 } \ 151} 152 153 154u_char 155sl_compress_tcp(struct mbuf * m, 156 struct ip * ip, 157 struct slcompress *comp, 158 struct slstat *slstat, 159 int compress_cid) 160{ 161 register struct cstate *cs = comp->last_cs->cs_next; 162 register u_int hlen = ip->ip_hl; 163 register struct tcphdr *oth; 164 register struct tcphdr *th; 165 register u_int deltaS, deltaA; 166 register u_int changes = 0; 167 u_char new_seq[16]; 168 register u_char *cp = new_seq; 169 170 /* 171 * Bail if this is an IP fragment or if the TCP packet isn't `compressible' 172 * (i.e., ACK isn't set or some other control bit is set). (We assume that 173 * the caller has already made sure the packet is IP proto TCP). 174 */ 175 if ((ip->ip_off & htons(0x3fff)) || m->m_len < 40) { 176 log_Printf(LogDEBUG, "??? 1 ip_off = %x, m_len = %lu\n", 177 ip->ip_off, (unsigned long)m->m_len); 178 log_DumpBp(LogDEBUG, "", m); 179 return (TYPE_IP); 180 } 181 th = (struct tcphdr *) & ((int *) ip)[hlen]; 182 if ((th->th_flags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) != TH_ACK) { 183 log_Printf(LogDEBUG, "??? 2 th_flags = %x\n", th->th_flags); 184 log_DumpBp(LogDEBUG, "", m); 185 return (TYPE_IP); 186 } 187 188 /* 189 * Packet is compressible -- we're going to send either a COMPRESSED_TCP or 190 * UNCOMPRESSED_TCP packet. Either way we need to locate (or create) the 191 * connection state. Special case the most recently used connection since 192 * it's most likely to be used again & we don't have to do any reordering 193 * if it's used. 194 */ 195 slstat->sls_packets++; 196 if (ip->ip_src.s_addr != cs->cs_ip.ip_src.s_addr || 197 ip->ip_dst.s_addr != cs->cs_ip.ip_dst.s_addr || 198 *(int *) th != ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) { 199 200 /* 201 * Wasn't the first -- search for it. 202 * 203 * States are kept in a circularly linked list with last_cs pointing to the 204 * end of the list. The list is kept in lru order by moving a state to 205 * the head of the list whenever it is referenced. Since the list is 206 * short and, empirically, the connection we want is almost always near 207 * the front, we locate states via linear search. If we don't find a 208 * state for the datagram, the oldest state is (re-)used. 209 */ 210 register struct cstate *lcs; 211 register struct cstate *lastcs = comp->last_cs; 212 213 do { 214 lcs = cs; 215 cs = cs->cs_next; 216 slstat->sls_searches++; 217 if (ip->ip_src.s_addr == cs->cs_ip.ip_src.s_addr 218 && ip->ip_dst.s_addr == cs->cs_ip.ip_dst.s_addr 219 && *(int *) th == ((int *) &cs->cs_ip)[cs->cs_ip.ip_hl]) 220 goto found; 221 } while (cs != lastcs); 222 223 /* 224 * Didn't find it -- re-use oldest cstate. Send an uncompressed packet 225 * that tells the other side what connection number we're using for this 226 * conversation. Note that since the state list is circular, the oldest 227 * state points to the newest and we only need to set last_cs to update 228 * the lru linkage. 229 */ 230 slstat->sls_misses++; 231 comp->last_cs = lcs; 232#define THOFFSET(th) (th->th_off) 233 hlen += th->th_off; 234 hlen <<= 2; 235 if (hlen > m->m_len) 236 return (TYPE_IP); 237 goto uncompressed; 238 239found: 240 241 /* 242 * Found it -- move to the front on the connection list. 243 */ 244 if (cs == lastcs) 245 comp->last_cs = lcs; 246 else { 247 lcs->cs_next = cs->cs_next; 248 cs->cs_next = lastcs->cs_next; 249 lastcs->cs_next = cs; 250 } 251 } 252 253 /* 254 * Make sure that only what we expect to change changed. The first line of 255 * the `if' checks the IP protocol version, header length & type of 256 * service. The 2nd line checks the "Don't fragment" bit. The 3rd line 257 * checks the time-to-live and protocol (the protocol check is unnecessary 258 * but costless). The 4th line checks the TCP header length. The 5th line 259 * checks IP options, if any. The 6th line checks TCP options, if any. If 260 * any of these things are different between the previous & current 261 * datagram, we send the current datagram `uncompressed'. 262 */ 263 oth = (struct tcphdr *) & ((int *) &cs->cs_ip)[hlen]; 264 deltaS = hlen; 265 hlen += th->th_off; 266 hlen <<= 2; 267 if (hlen > m->m_len) 268 return (TYPE_IP); 269 270 if (((u_short *) ip)[0] != ((u_short *) & cs->cs_ip)[0] || 271 ((u_short *) ip)[3] != ((u_short *) & cs->cs_ip)[3] || 272 ((u_short *) ip)[4] != ((u_short *) & cs->cs_ip)[4] || 273 THOFFSET(th) != THOFFSET(oth) || 274 (deltaS > 5 && 275 memcmp(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) || 276 (THOFFSET(th) > 5 && 277 memcmp(th + 1, oth + 1, (THOFFSET(th) - 5) << 2))) { 278 goto uncompressed; 279 } 280 281 /* 282 * Figure out which of the changing fields changed. The receiver expects 283 * changes in the order: urgent, window, ack, seq (the order minimizes the 284 * number of temporaries needed in this section of code). 285 */ 286 if (th->th_flags & TH_URG) { 287 deltaS = ntohs(th->th_urp); 288 ENCODEZ(deltaS); 289 changes |= NEW_U; 290 } else if (th->th_urp != oth->th_urp) { 291 292 /* 293 * argh! URG not set but urp changed -- a sensible implementation should 294 * never do this but RFC793 doesn't prohibit the change so we have to 295 * deal with it. 296 */ 297 goto uncompressed; 298 } 299 deltaS = (u_short) (ntohs(th->th_win) - ntohs(oth->th_win)); 300 if (deltaS) { 301 ENCODE(deltaS); 302 changes |= NEW_W; 303 } 304 deltaA = ntohl(th->th_ack) - ntohl(oth->th_ack); 305 if (deltaA) { 306 if (deltaA > 0xffff) { 307 goto uncompressed; 308 } 309 ENCODE(deltaA); 310 changes |= NEW_A; 311 } 312 deltaS = ntohl(th->th_seq) - ntohl(oth->th_seq); 313 if (deltaS) { 314 if (deltaS > 0xffff) { 315 goto uncompressed; 316 } 317 ENCODE(deltaS); 318 changes |= NEW_S; 319 } 320 switch (changes) { 321 322 case 0: 323 324 /* 325 * Nothing changed. If this packet contains data and the last one didn't, 326 * this is probably a data packet following an ack (normal on an 327 * interactive connection) and we send it compressed. Otherwise it's 328 * probably a retransmit, retransmitted ack or window probe. Send it 329 * uncompressed in case the other side missed the compressed version. 330 */ 331 if (ip->ip_len != cs->cs_ip.ip_len && 332 ntohs(cs->cs_ip.ip_len) == hlen) 333 break; 334 335 /* FALLTHROUGH */ 336 337 case SPECIAL_I: 338 case SPECIAL_D: 339 340 /* 341 * actual changes match one of our special case encodings -- send packet 342 * uncompressed. 343 */ 344 goto uncompressed; 345 346 case NEW_S | NEW_A: 347 if (deltaS == deltaA && 348 deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 349 /* special case for echoed terminal traffic */ 350 changes = SPECIAL_I; 351 cp = new_seq; 352 } 353 break; 354 355 case NEW_S: 356 if (deltaS == ntohs(cs->cs_ip.ip_len) - hlen) { 357 /* special case for data xfer */ 358 changes = SPECIAL_D; 359 cp = new_seq; 360 } 361 break; 362 } 363 364 deltaS = ntohs(ip->ip_id) - ntohs(cs->cs_ip.ip_id); 365 if (deltaS != 1) { 366 ENCODEZ(deltaS); 367 changes |= NEW_I; 368 } 369 if (th->th_flags & TH_PUSH) 370 changes |= TCP_PUSH_BIT; 371 372 /* 373 * Grab the cksum before we overwrite it below. Then update our state with 374 * this packet's header. 375 */ 376 deltaA = ntohs(th->th_sum); 377 memcpy(&cs->cs_ip, ip, hlen); 378 379 /* 380 * We want to use the original packet as our compressed packet. (cp - 381 * new_seq) is the number of bytes we need for compressed sequence numbers. 382 * In addition we need one byte for the change mask, one for the connection 383 * id and two for the tcp checksum. So, (cp - new_seq) + 4 bytes of header 384 * are needed. hlen is how many bytes of the original packet to toss so 385 * subtract the two to get the new packet size. 386 */ 387 deltaS = cp - new_seq; 388 cp = (u_char *) ip; 389 390 /* 391 * Since fastq traffic can jump ahead of the background traffic, we don't 392 * know what order packets will go on the line. In this case, we always 393 * send a "new" connection id so the receiver state stays synchronized. 394 */ 395 if (comp->last_xmit == cs->cs_id && compress_cid) { 396 hlen -= deltaS + 3; 397 cp += hlen; 398 *cp++ = changes; 399 } else { 400 comp->last_xmit = cs->cs_id; 401 hlen -= deltaS + 4; 402 cp += hlen; 403 *cp++ = changes | NEW_C; 404 *cp++ = cs->cs_id; 405 } 406 m->m_len -= hlen; 407 m->m_offset += hlen; 408 *cp++ = deltaA >> 8; 409 *cp++ = deltaA; 410 memcpy(cp, new_seq, deltaS); 411 slstat->sls_compressed++; 412 return (TYPE_COMPRESSED_TCP); 413 414 /* 415 * Update connection state cs & send uncompressed packet ('uncompressed' 416 * means a regular ip/tcp packet but with the 'conversation id' we hope to 417 * use on future compressed packets in the protocol field). 418 */ 419uncompressed: 420 memcpy(&cs->cs_ip, ip, hlen); 421 ip->ip_p = cs->cs_id; 422 comp->last_xmit = cs->cs_id; 423 return (TYPE_UNCOMPRESSED_TCP); 424} 425 426 427int 428sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp, 429 struct slstat *slstat, int max_state) 430{ 431 register u_char *cp; 432 register u_int hlen, changes; 433 register struct tcphdr *th; 434 register struct cstate *cs; 435 register struct ip *ip; 436 u_short *bp; 437 438 switch (type) { 439 440 case TYPE_UNCOMPRESSED_TCP: 441 ip = (struct ip *) * bufp; 442 if (ip->ip_p > max_state) 443 goto bad; 444 cs = &comp->rstate[comp->last_recv = ip->ip_p]; 445 comp->flags &= ~SLF_TOSS; 446 ip->ip_p = IPPROTO_TCP; 447 448 /* 449 * Calculate the size of the TCP/IP header and make sure that we don't 450 * overflow the space we have available for it. 451 */ 452 hlen = ip->ip_hl << 2; 453 if ((int)(hlen + sizeof(struct tcphdr)) > len) 454 goto bad; 455 th = (struct tcphdr *) & ((char *) ip)[hlen]; 456 hlen += THOFFSET(th) << 2; 457 if (hlen > MAX_HDR) 458 goto bad; 459 memcpy(&cs->cs_ip, ip, hlen); 460 cs->cs_hlen = hlen; 461 slstat->sls_uncompressedin++; 462 return (len); 463 464 default: 465 goto bad; 466 467 case TYPE_COMPRESSED_TCP: 468 break; 469 } 470 471 /* We've got a compressed packet. */ 472 slstat->sls_compressedin++; 473 cp = *bufp; 474 changes = *cp++; 475 log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes); 476 477 if (changes & NEW_C) { 478 /* 479 * Make sure the state index is in range, then grab the state. If we have 480 * a good state index, clear the 'discard' flag. 481 */ 482 if (*cp > max_state || comp->last_recv == 255) 483 goto bad; 484 485 comp->flags &= ~SLF_TOSS; 486 comp->last_recv = *cp++; 487 } else { 488 /* 489 * this packet has an implicit state index. If we've had a line error 490 * since the last time we got an explicit state index, we have to toss 491 * the packet. 492 */ 493 if (comp->flags & SLF_TOSS) { 494 slstat->sls_tossed++; 495 return (0); 496 } 497 } 498 cs = &comp->rstate[comp->last_recv]; 499 hlen = cs->cs_ip.ip_hl << 2; 500 th = (struct tcphdr *) & ((u_char *) & cs->cs_ip)[hlen]; 501 th->th_sum = htons((*cp << 8) | cp[1]); 502 cp += 2; 503 if (changes & TCP_PUSH_BIT) 504 th->th_flags |= TH_PUSH; 505 else 506 th->th_flags &= ~TH_PUSH; 507 508 switch (changes & SPECIALS_MASK) { 509 case SPECIAL_I: 510 { 511 register u_int i = ntohs(cs->cs_ip.ip_len) - cs->cs_hlen; 512 513 th->th_ack = htonl(ntohl(th->th_ack) + i); 514 th->th_seq = htonl(ntohl(th->th_seq) + i); 515 } 516 break; 517 518 case SPECIAL_D: 519 th->th_seq = htonl(ntohl(th->th_seq) + ntohs(cs->cs_ip.ip_len) 520 - cs->cs_hlen); 521 break; 522 523 default: 524 if (changes & NEW_U) { 525 th->th_flags |= TH_URG; 526 DECODEU(th->th_urp) 527 } else 528 th->th_flags &= ~TH_URG; 529 if (changes & NEW_W) 530 DECODES(th->th_win) 531 if (changes & NEW_A) 532 DECODEL(th->th_ack) 533 if (changes & NEW_S) { 534 log_Printf(LogDEBUG, "NEW_S: %02x, %02x, %02x\n", 535 *cp, cp[1], cp[2]); 536 DECODEL(th->th_seq) 537 } 538 break; 539 } 540 if (changes & NEW_I) { 541 DECODES(cs->cs_ip.ip_id) 542 } else 543 cs->cs_ip.ip_id = htons(ntohs(cs->cs_ip.ip_id) + 1); 544 545 log_Printf(LogDEBUG, "Uncompress: id = %04x, seq = %08lx\n", 546 cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq)); 547 548 /* 549 * At this point, cp points to the first byte of data in the packet. 550 * Back up cp by the tcp/ip header length to make room for the 551 * reconstructed header (we assume the packet we were handed has enough 552 * space to prepend 128 bytes of header). Adjust the length to account 553 * for the new header & fill in the IP total length. 554 */ 555 len -= (cp - *bufp); 556 if (len < 0) 557 /* 558 * we must have dropped some characters (crc should detect this but the 559 * old slip framing won't) 560 */ 561 goto bad; 562 563 *bufp = cp - cs->cs_hlen; 564 len += cs->cs_hlen; 565 cs->cs_ip.ip_len = htons(len); 566 567 /* recompute the ip header checksum */ 568 cs->cs_ip.ip_sum = 0; 569 bp = (u_short *)&cs->cs_ip; 570 for (changes = 0; hlen > 0; hlen -= 2) 571 changes += *bp++; 572 changes = (changes & 0xffff) + (changes >> 16); 573 changes = (changes & 0xffff) + (changes >> 16); 574 cs->cs_ip.ip_sum = ~changes; 575 576 /* And copy the result into our buffer */ 577 memcpy(*bufp, &cs->cs_ip, cs->cs_hlen); 578 579 return (len); 580bad: 581 comp->flags |= SLF_TOSS; 582 slstat->sls_errorin++; 583 return (0); 584} 585 586int 587sl_Show(struct cmdargs const *arg) 588{ 589 prompt_Printf(arg->prompt, "VJ compression statistics:\n"); 590 prompt_Printf(arg->prompt, " Out: %d (compress) / %d (total)", 591 arg->bundle->ncp.ipcp.vj.slstat.sls_compressed, 592 arg->bundle->ncp.ipcp.vj.slstat.sls_packets); 593 prompt_Printf(arg->prompt, " %d (miss) / %d (search)\n", 594 arg->bundle->ncp.ipcp.vj.slstat.sls_misses, 595 arg->bundle->ncp.ipcp.vj.slstat.sls_searches); 596 prompt_Printf(arg->prompt, " In: %d (compress), %d (uncompress)", 597 arg->bundle->ncp.ipcp.vj.slstat.sls_compressedin, 598 arg->bundle->ncp.ipcp.vj.slstat.sls_uncompressedin); 599 prompt_Printf(arg->prompt, " %d (error), %d (tossed)\n", 600 arg->bundle->ncp.ipcp.vj.slstat.sls_errorin, 601 arg->bundle->ncp.ipcp.vj.slstat.sls_tossed); 602 return 0; 603} 604