if_sl.c revision 1.7
1/* 2 * Copyright (c) 1987, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from if_sl.c,v 1.11 84/10/04 12:54:47 rick Exp 34 * 35 * from: @(#)if_sl.c 7.22 (Berkeley) 4/20/91 36 * $Id: if_sl.c,v 1.7 1993/05/18 18:19:56 cgd Exp $ 37 */ 38 39/* 40 * Serial Line interface 41 * 42 * Rick Adams 43 * Center for Seismic Studies 44 * 1300 N 17th Street, Suite 1450 45 * Arlington, Virginia 22209 46 * (703)276-7900 47 * rick@seismo.ARPA 48 * seismo!rick 49 * 50 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). 51 * N.B.: this belongs in netinet, not net, the way it stands now. 52 * Should have a link-layer type designation, but wouldn't be 53 * backwards-compatible. 54 * 55 * Converted to 4.3BSD Beta by Chris Torek. 56 * Other changes made at Berkeley, based in part on code by Kirk Smith. 57 * W. Jolitz added slip abort. 58 * 59 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov). 60 * Added priority queuing for "interactive" traffic; hooks for TCP 61 * header compression; ICMP filtering (at 2400 baud, some cretin 62 * pinging you can use up all your bandwidth). Made low clist behavior 63 * more robust and slightly less likely to hang serial line. 64 * Sped up a bunch of things. 65 * 66 * Note that splimp() is used throughout to block both (tty) input 67 * interrupts and network activity; thus, splimp must be >= spltty. 68 */ 69 70#include "sl.h" 71#if NSL > 0 72 73#include "param.h" 74#include "proc.h" 75#include "mbuf.h" 76#include "buf.h" 77#include "dkstat.h" 78#include "socket.h" 79#include "ioctl.h" 80#include "file.h" 81#include "select.h" 82#include "tty.h" 83#include "kernel.h" 84#include "conf.h" 85 86#include "if.h" 87#include "if_types.h" 88#include "netisr.h" 89#include "route.h" 90#if INET 91#include "netinet/in.h" 92#include "netinet/in_systm.h" 93#include "netinet/in_var.h" 94#include "netinet/ip.h" 95#else 96Huh? Slip without inet? 97#endif 98 99#include "machine/mtpr.h" 100 101#include "slcompress.h" 102#include "if_slvar.h" 103#include "slip.h" 104 105#include "bpfilter.h" 106#if NBPFILTER > 0 107#include <sys/time.h> 108#include <net/bpf.h> 109#endif 110 111/* 112 * SLMAX is a hard limit on input packet size. To simplify the code 113 * and improve performance, we require that packets fit in an mbuf 114 * cluster, and if we get a compressed packet, there's enough extra 115 * room to expand the header into a max length tcp/ip header (128 116 * bytes). So, SLMAX can be at most 117 * MCLBYTES - 128 118 * 119 * SLMTU is a hard limit on output packet size. To insure good 120 * interactive response, SLMTU wants to be the smallest size that 121 * amortizes the header cost. (Remember that even with 122 * type-of-service queuing, we have to wait for any in-progress 123 * packet to finish. I.e., we wait, on the average, 1/2 * mtu / 124 * cps, where cps is the line speed in characters per second. 125 * E.g., 533ms wait for a 1024 byte MTU on a 9600 baud line. The 126 * average compressed header size is 6-8 bytes so any MTU > 90 127 * bytes will give us 90% of the line bandwidth. A 100ms wait is 128 * tolerable (500ms is not), so want an MTU around 296. (Since TCP 129 * will send 256 byte segments (to allow for 40 byte headers), the 130 * typical packet size on the wire will be around 260 bytes). In 131 * 4.3tahoe+ systems, we can set an MTU in a route so we do that & 132 * leave the interface MTU relatively high (so we don't IP fragment 133 * when acting as a gateway to someone using a stupid MTU). 134 * 135 * Similar considerations apply to SLIP_HIWAT: It's the amount of 136 * data that will be queued 'downstream' of us (i.e., in clists 137 * waiting to be picked up by the tty output interrupt). If we 138 * queue a lot of data downstream, it's immune to our t.o.s. queuing. 139 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 140 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 141 * wait is dependent on the ftp window size but that's typically 142 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 143 * the cost (in idle time on the wire) of the tty driver running 144 * off the end of its clists & having to call back slstart for a 145 * new packet. For a tty interface with any buffering at all, this 146 * cost will be zero. Even with a totally brain dead interface (like 147 * the one on a typical workstation), the cost will be <= 1 character 148 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 149 * at most 1% while maintaining good interactive response. 150 */ 151#if NBPFILTER > 0 152#define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 153#else 154#define BUFOFFSET (128+sizeof(struct ifnet **)) 155#endif 156#define SLMAX (MCLBYTES - BUFOFFSET) 157#define SLBUFSIZE (SLMAX + BUFOFFSET) 158#define SLMTU 296 /* try 1006 later */ 159#define SLIP_HIWAT roundup(50,CBSIZE) 160 161/* 162 * SLIP ABORT ESCAPE MECHANISM: 163 * (inspired by HAYES modem escape arrangement) 164 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 165 * signals a "soft" exit from slip mode by usermode process 166 */ 167 168#ifdef ABT_ESC 169#undef ABT_ESC 170#define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 171#define ABT_WAIT 1 /* in seconds - idle before an escape & after */ 172#define ABT_RECYCLE (5*2+2) /* in seconds - time window processing abort */ 173#define ABT_SOFT 3 /* count of escapes */ 174#endif /* ABT_ESC */ 175 176/* 177 * The following disgusting hack gets around the problem that IP TOS 178 * can't be set yet. We want to put "interactive" traffic on a high 179 * priority queue. To decide if traffic is interactive, we check that 180 * a) it is TCP and b) one of its ports is telnet, rlogin or ftp control. 181 */ 182static u_short interactive_ports[8] = { 183 0, 513, 0, 0, 184 0, 21, 0, 23, 185}; 186#define INTERACTIVE(p) (interactive_ports[(p) & 7] == (p)) 187 188struct sl_softc sl_softc[NSL]; 189 190#define FRAME_END 0xc0 /* Frame End */ 191#define FRAME_ESCAPE 0xdb /* Frame Esc */ 192#define TRANS_FRAME_END 0xdc /* transposed frame end */ 193#define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 194 195#define t_sc T_LINEP 196 197int sloutput(), slioctl(), ttrstrt(); 198extern struct timeval time; 199 200/* 201 * Called from boot code to establish sl interfaces. 202 */ 203slattach() 204{ 205 register struct sl_softc *sc; 206 register int i = 0; 207 208 for (sc = sl_softc; i < NSL; sc++) { 209 sc->sc_if.if_name = "sl"; 210 sc->sc_if.if_unit = i++; 211 sc->sc_if.if_mtu = SLMTU; 212 sc->sc_if.if_flags = IFF_POINTOPOINT; 213 sc->sc_if.if_type = IFT_SLIP; 214 sc->sc_if.if_ioctl = slioctl; 215 sc->sc_if.if_output = sloutput; 216 sc->sc_if.if_snd.ifq_maxlen = 50; 217 sc->sc_fastq.ifq_maxlen = 32; 218 if_attach(&sc->sc_if); 219#if NBPFILTER > 0 220 bpfattach(&sc->sc_bpf, &sc->sc_if, DLT_SLIP, 221 SLIP_HDRLEN); 222#endif 223 } 224} 225 226static int 227slinit(sc) 228 register struct sl_softc *sc; 229{ 230 register caddr_t p; 231 232 if (sc->sc_ep == (u_char *) 0) { 233 MCLALLOC(p, M_WAIT); 234 if (p) 235 sc->sc_ep = (u_char *)p + SLBUFSIZE; 236 else { 237 printf("sl%d: can't allocate buffer\n", sc - sl_softc); 238 sc->sc_if.if_flags &= ~IFF_UP; 239 return (0); 240 } 241 } 242 sc->sc_buf = sc->sc_ep - SLMAX; 243 sc->sc_mp = sc->sc_buf; 244 sl_compress_init(&sc->sc_comp); 245 return (1); 246} 247 248/* 249 * Line specific open routine. 250 * Attach the given tty to the first available sl unit. 251 */ 252/* ARGSUSED */ 253slopen(dev, tp) 254 dev_t dev; 255 register struct tty *tp; 256{ 257 struct proc *p = curproc; /* XXX */ 258 register struct sl_softc *sc; 259 register int nsl; 260 int error; 261 262 if (error = suser(p->p_ucred, &p->p_acflag)) 263 return (error); 264 265 if (tp->t_line == SLIPDISC) 266 return (0); 267 268 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 269 if (sc->sc_ttyp == NULL) { 270 if (slinit(sc) == 0) 271 return (ENOBUFS); 272 tp->t_sc = (caddr_t)sc; 273 sc->sc_ttyp = tp; 274 sc->sc_if.if_baudrate = tp->t_ospeed; 275 ttyflush(tp, FREAD | FWRITE); 276 return (0); 277 } 278 return (ENXIO); 279} 280 281/* 282 * Line specific close routine. 283 * Detach the tty from the sl unit. 284 * Mimics part of ttyclose(). 285 */ 286slclose(tp) 287 struct tty *tp; 288{ 289 register struct sl_softc *sc; 290 int s; 291 292 ttywflush(tp); 293 s = splimp(); /* actually, max(spltty, splnet) */ 294 tp->t_line = 0; 295 sc = (struct sl_softc *)tp->t_sc; 296 if (sc != NULL) { 297 if_down(&sc->sc_if); 298 sc->sc_ttyp = NULL; 299 tp->t_sc = NULL; 300 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE)); 301 sc->sc_ep = 0; 302 sc->sc_mp = 0; 303 sc->sc_buf = 0; 304 } 305 splx(s); 306} 307 308/* 309 * Line specific (tty) ioctl routine. 310 * Provide a way to get the sl unit number. 311 */ 312/* ARGSUSED */ 313sltioctl(tp, cmd, data, flag) 314 struct tty *tp; 315 caddr_t data; 316{ 317 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 318 int s; 319 320 switch (cmd) { 321 case SLIOCGUNIT: 322 *(int *)data = sc->sc_if.if_unit; 323 break; 324 325 case SLIOCGFLAGS: 326 *(int *)data = sc->sc_flags; 327 break; 328 329 case SLIOCSFLAGS: 330#define SC_MASK 0xffff 331 s = splimp(); 332 sc->sc_flags = 333 (sc->sc_flags &~ SC_MASK) | ((*(int *)data) & SC_MASK); 334 splx(s); 335 break; 336 337 default: 338 return (-1); 339 } 340 return (0); 341} 342 343/* 344 * Queue a packet. Start transmission if not active. 345 */ 346sloutput(ifp, m, dst) 347 struct ifnet *ifp; 348 register struct mbuf *m; 349 struct sockaddr *dst; 350{ 351 register struct sl_softc *sc = &sl_softc[ifp->if_unit]; 352 register struct ip *ip; 353 register struct ifqueue *ifq; 354 int s; 355 356 /* 357 * `Cannot happen' (see slioctl). Someday we will extend 358 * the line protocol to support other address families. 359 */ 360 if (dst->sa_family != AF_INET) { 361 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit, 362 dst->sa_family); 363 m_freem(m); 364 return (EAFNOSUPPORT); 365 } 366 367 if (sc->sc_ttyp == NULL) { 368 m_freem(m); 369 return (ENETDOWN); /* sort of */ 370 } 371 if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0) { 372 m_freem(m); 373 return (EHOSTUNREACH); 374 } 375 ifq = &sc->sc_if.if_snd; 376 if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) { 377 u_short srcport = ntohs(((short *)ip)[ip->ip_hl << 1]); 378 u_short dstport = ntohs(((short *)ip)[(ip->ip_hl << 1) + 1]); 379 380 if (INTERACTIVE(srcport) || INTERACTIVE(dstport)) { 381 ifq = &sc->sc_fastq; 382 } 383 384 } else if (sc->sc_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 385 m_freem(m); 386 return (0); 387 } 388 s = splimp(); 389 if (IF_QFULL(ifq)) { 390 IF_DROP(ifq); 391 m_freem(m); 392 splx(s); 393 sc->sc_if.if_oerrors++; 394 return (ENOBUFS); 395 } 396 IF_ENQUEUE(ifq, m); 397 sc->sc_if.if_lastchange = time; 398 if (RB_LEN(&sc->sc_ttyp->t_out) == 0) 399 slstart(sc->sc_ttyp); 400 splx(s); 401 return (0); 402} 403 404/* 405 * Start output on interface. Get another datagram 406 * to send from the interface queue and map it to 407 * the interface before starting output. 408 */ 409slstart(tp) 410 register struct tty *tp; 411{ 412 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 413 register struct mbuf *m; 414 register u_char *cp; 415 register struct ip *ip; 416 int s; 417 struct mbuf *m2; 418#if NBPFILTER > 0 419 u_char bpfbuf[SLMTU + SLIP_HDRLEN]; 420 register int len; 421#endif 422 423 for (;;) { 424 /* 425 * If there is more in the output queue, just send it now. 426 * We are being called in lieu of ttstart and must do what 427 * it would. 428 */ 429 if (RB_LEN(&tp->t_out) != 0) { 430 (*tp->t_oproc)(tp); 431 if (RB_LEN(&tp->t_out) > SLIP_HIWAT) 432 return; 433 } 434 /* 435 * This happens briefly when the line shuts down. 436 */ 437 if (sc == NULL) 438 return; 439 440 /* 441 * Do not remove the packet from the IP queue if it 442 * doesn't look like the packet will fit into the 443 * current COM output queue, with a packet full of 444 * escapes this could be as bad as SLMTU*2. The value 445 * of RBSZ in tty.h also has to be upped to be at least 446 * SLMTU*2. 447 */ 448 if (RBSZ - RB_LEN(&tp->t_out) < 2 * SLMTU + 2) 449 return; 450 451 /* 452 * Get a packet and send it to the interface. 453 */ 454 s = splimp(); 455 IF_DEQUEUE(&sc->sc_fastq, m); 456 if (m == NULL) 457 IF_DEQUEUE(&sc->sc_if.if_snd, m); 458 splx(s); 459 if (m == NULL) 460 return; 461 /* 462 * We do the header compression here rather than in sl_output 463 * because the packets will be out of order if we are using TOS 464 * queueing, and the connection id compression will get messed 465 * up when this happens. 466 */ 467#if NBPFILTER > 0 468 if (sc->sc_bpf) { 469 /* 470 * We need to save the TCP/IP header before it's compressed. 471 * To avoid complicated code, we just copy the entire packet 472 * into a stack buffer (since this is a serial line, packets 473 * should be short and/or the copy should be negligible cost 474 * compared to the packet transmission time). 475 */ 476 register struct mbuf *m1 = m; 477 register u_char *cp = bpfbuf + SLIP_HDRLEN; 478 len = 0; 479 do { 480 register int mlen = m1->m_len; 481 482 bcopy(mtod(m1, caddr_t), cp, mlen); 483 cp += mlen; 484 len += mlen; 485 } while (m1 = m1->m_next); 486 } 487#endif 488 if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) { 489 if (sc->sc_flags & SC_COMPRESS) 490 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, &sc->sc_comp, 1); 491 } 492#if NBPFILTER > 0 493 if (sc->sc_bpf) { 494 /* 495 * Put the SLIP pseudo-"link header" in place. The compressed 496 * header is now at the beginning of the mbuf. 497 */ 498 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 499 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 500 bpf_tap(sc->sc_bpf, bpfbuf, len + SLIP_HDRLEN); 501 } 502#endif 503 504 sc->sc_if.if_lastchange = time; 505 506 /* 507 * The extra FRAME_END will start up a new packet, and thus 508 * will flush any accumulated garbage. We do this whenever 509 * the line may have been idle for some time. 510 */ 511 if (RB_LEN(&tp->t_out) == 0) { 512 ++sc->sc_bytessent; 513 (void) putc(FRAME_END, &tp->t_out); 514 } 515 516 while (m) { 517 register u_char *ep; 518 519 cp = mtod(m, u_char *); ep = cp + m->m_len; 520 while (cp < ep) { 521 /* 522 * Find out how many bytes in the string we can 523 * handle without doing something special. 524 */ 525 register u_char *bp = cp; 526 527 while (cp < ep) { 528 switch (*cp++) { 529 case FRAME_ESCAPE: 530 case FRAME_END: 531 --cp; 532 goto out; 533 } 534 } 535 out: 536 if (cp > bp) { 537 /* 538 * Put the non-special bytes 539 * into the tty output queue. 540 */ 541 sc->sc_bytessent += rb_cwrite( 542 &tp->t_out, 543 (char *) bp, 544 cp - bp); 545 } 546 /* 547 * If there are characters left in the mbuf, 548 * the first one must be special.. 549 * Put it out in a different form. 550 */ 551 if (cp < ep) { 552 if (putc(FRAME_ESCAPE, &tp->t_out)) 553 break; 554 if (putc(*cp++ == FRAME_ESCAPE ? 555 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 556 &tp->t_out)) { 557 (void) unputc(&tp->t_out); 558 break; 559 } 560 sc->sc_bytessent += 2; 561 } 562 } 563 MFREE(m, m2); 564 m = m2; 565 } 566 567 if (putc(FRAME_END, &tp->t_out)) { 568 /* 569 * Not enough room. Remove a char to make room 570 * and end the packet normally. 571 * If you get many collisions (more than one or two 572 * a day) you probably do not have enough clists 573 * and you should increase "nclist" in param.c. 574 */ 575 (void) unputc(&tp->t_out); 576 (void) putc(FRAME_END, &tp->t_out); 577 sc->sc_if.if_collisions++; 578 } else { 579 ++sc->sc_bytessent; 580 sc->sc_if.if_opackets++; 581 } 582 sc->sc_if.if_obytes = sc->sc_bytessent; 583 } 584} 585 586/* 587 * Copy data buffer to mbuf chain; add ifnet pointer. 588 */ 589static struct mbuf * 590sl_btom(sc, len) 591 register struct sl_softc *sc; 592 register int len; 593{ 594 register struct mbuf *m; 595 596 MGETHDR(m, M_DONTWAIT, MT_DATA); 597 if (m == NULL) 598 return (NULL); 599 600 /* 601 * If we have more than MHLEN bytes, it's cheaper to 602 * queue the cluster we just filled & allocate a new one 603 * for the input buffer. Otherwise, fill the mbuf we 604 * allocated above. Note that code in the input routine 605 * guarantees that packet will fit in a cluster. 606 */ 607 if (len >= MHLEN) { 608 MCLGET(m, M_DONTWAIT); 609 if ((m->m_flags & M_EXT) == 0) { 610 /* 611 * we couldn't get a cluster - if memory's this 612 * low, it's time to start dropping packets. 613 */ 614 (void) m_free(m); 615 return (NULL); 616 } 617 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 618 m->m_data = (caddr_t)sc->sc_buf; 619 m->m_ext.ext_buf = (caddr_t)((int)sc->sc_buf &~ MCLOFSET); 620 } else 621 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 622 623 m->m_len = len; 624 m->m_pkthdr.len = len; 625 m->m_pkthdr.rcvif = &sc->sc_if; 626 return (m); 627} 628 629/* 630 * tty interface receiver interrupt. 631 */ 632slinput(c, tp) 633 register int c; 634 register struct tty *tp; 635{ 636 register struct sl_softc *sc; 637 register struct mbuf *m; 638 register int len; 639 int s; 640#if NBPFILTER > 0 641 u_char chdr[CHDR_LEN]; 642#endif 643 tk_nin++; 644 sc = (struct sl_softc *)tp->t_sc; 645 if (sc == NULL) 646 return; 647 if (c & TTY_ERRORMASK|| !(tp->t_state&TS_CARR_ON)) { 648 sc->sc_flags |= SC_ERROR; 649 return; 650 } 651 652 ++sc->sc_bytesrcvd; 653 ++sc->sc_if.if_ibytes; 654 655#ifdef ABT_ESC 656 if (sc->sc_flags & SC_ABORT) { 657 /* if we see an abort after "idle" time, count it */ 658 if (c == ABT_ESC && time.tv_sec >= sc->sc_lasttime + ABT_WAIT) { 659 sc->sc_abortcount++; 660 /* record when the first abort escape arrived */ 661 if (sc->sc_abortcount == 1) 662 sc->sc_starttime = time.tv_sec; 663 } 664 /* 665 * if we have an abort, see that we have not run out of time, 666 * or that we have an "idle" time after the complete escape 667 * sequence 668 */ 669 if (sc->sc_abortcount) { 670 if (time.tv_sec >= sc->sc_starttime + ABT_RECYCLE) 671 sc->sc_abortcount = 0; 672 if (sc->sc_abortcount >= ABT_SOFT && 673 time.tv_sec >= sc->sc_lasttime + ABT_WAIT) { 674 slclose(tp); 675 return; 676 } 677 } 678 sc->sc_lasttime = time.tv_sec; 679 } 680#endif 681 682 switch (c) { 683 684 case TRANS_FRAME_ESCAPE: 685 if (sc->sc_escape) 686 c = FRAME_ESCAPE; 687 break; 688 689 case TRANS_FRAME_END: 690 if (sc->sc_escape) 691 c = FRAME_END; 692 break; 693 694 case FRAME_ESCAPE: 695 sc->sc_escape = 1; 696 return; 697 698 case FRAME_END: 699 if(sc->sc_flags & SC_ERROR) { 700 sc->sc_flags &= ~SC_ERROR; 701 goto newpack; 702 } 703 len = sc->sc_mp - sc->sc_buf; 704 705 if (len < 3) 706 /* less than min length packet - ignore */ 707 goto newpack; 708 709#if NBPFILTER > 0 710 if (sc->sc_bpf) 711 /* 712 * Save the compressed header, so we can 713 * tack it on later. Note that we just 714 * we will end up copying garbage in some 715 * cases but this is okay. We remember 716 * where the buffer started so we can 717 * compute the new header length. 718 */ 719 bcopy(sc->sc_buf, chdr, CHDR_LEN); 720#endif 721 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 722 if (c & 0x80) 723 c = TYPE_COMPRESSED_TCP; 724 else if (c == TYPE_UNCOMPRESSED_TCP) 725 *sc->sc_buf &= 0x4f; /* XXX */ 726 /* 727 * We've got something that's not an IP packet. 728 * If compression is enabled, try to decompress it. 729 * Otherwise, if `auto-enable' compression is on and 730 * it's a reasonable packet, decompress it and then 731 * enable compression. Otherwise, drop it. 732 */ 733 if (sc->sc_flags & SC_COMPRESS) { 734 len = sl_uncompress_tcp(&sc->sc_buf, len, 735 (u_int)c, &sc->sc_comp); 736 if (len <= 0) 737 goto error; 738 } else if ((sc->sc_flags & SC_AUTOCOMP) && 739 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 740 len = sl_uncompress_tcp(&sc->sc_buf, len, 741 (u_int)c, &sc->sc_comp); 742 if (len <= 0) 743 goto error; 744 sc->sc_flags |= SC_COMPRESS; 745 } else 746 goto error; 747 } 748#if NBPFILTER > 0 749 if (sc->sc_bpf) { 750 /* 751 * Put the SLIP pseudo-"link header" in place. 752 * We couldn't do this any earlier since 753 * decompression probably moved the buffer 754 * pointer. Then, invoke BPF. 755 */ 756 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 757 758 hp[SLX_DIR] = SLIPDIR_IN; 759 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 760 bpf_tap(sc->sc_bpf, hp, len + SLIP_HDRLEN); 761 } 762#endif 763 m = sl_btom(sc, len); 764 if (m == NULL) 765 goto error; 766 767 sc->sc_if.if_ipackets++; 768 sc->sc_if.if_lastchange = time; 769 s = splimp(); 770 if (IF_QFULL(&ipintrq)) { 771 IF_DROP(&ipintrq); 772 sc->sc_if.if_ierrors++; 773 sc->sc_if.if_iqdrops++; 774 m_freem(m); 775 } else { 776 IF_ENQUEUE(&ipintrq, m); 777 schednetisr(NETISR_IP); 778 } 779 splx(s); 780 goto newpack; 781 } 782 if (sc->sc_mp < sc->sc_ep) { 783 *sc->sc_mp++ = c; 784 sc->sc_escape = 0; 785 return; 786 } 787 sc->sc_flags |= SC_ERROR; 788error: 789 sc->sc_if.if_ierrors++; 790newpack: 791 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLMAX; 792 sc->sc_escape = 0; 793} 794 795/* 796 * Process an ioctl request. 797 */ 798slioctl(ifp, cmd, data) 799 register struct ifnet *ifp; 800 int cmd; 801 caddr_t data; 802{ 803 register struct ifaddr *ifa = (struct ifaddr *)data; 804 int s = splimp(), error = 0; 805 806 switch (cmd) { 807 808 case SIOCSIFADDR: 809 if (ifa->ifa_addr->sa_family == AF_INET) 810 ifp->if_flags |= IFF_UP; 811 else 812 error = EAFNOSUPPORT; 813 break; 814 815 case SIOCSIFDSTADDR: 816 if (ifa->ifa_addr->sa_family != AF_INET) 817 error = EAFNOSUPPORT; 818 break; 819 820 default: 821 error = EINVAL; 822 } 823 splx(s); 824 return (error); 825} 826#endif 827