if_sl.c revision 1.24
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 * from: @(#)if_sl.c 7.22 (Berkeley) 4/20/91 35 * $Id: if_sl.c,v 1.24 1994/02/02 01:21:32 hpeyerl Exp $ 36 */ 37 38/* 39 * Serial Line interface 40 * 41 * Rick Adams 42 * Center for Seismic Studies 43 * 1300 N 17th Street, Suite 1450 44 * Arlington, Virginia 22209 45 * (703)276-7900 46 * rick@seismo.ARPA 47 * seismo!rick 48 * 49 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). 50 * N.B.: this belongs in netinet, not net, the way it stands now. 51 * Should have a link-layer type designation, but wouldn't be 52 * backwards-compatible. 53 * 54 * Converted to 4.3BSD Beta by Chris Torek. 55 * Other changes made at Berkeley, based in part on code by Kirk Smith. 56 * W. Jolitz added slip abort. 57 * 58 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov). 59 * Added priority queuing for "interactive" traffic; hooks for TCP 60 * header compression; ICMP filtering (at 2400 baud, some cretin 61 * pinging you can use up all your bandwidth). Made low clist behavior 62 * more robust and slightly less likely to hang serial line. 63 * Sped up a bunch of things. 64 * 65 * Note that splimp() is used throughout to block both (tty) input 66 * interrupts and network activity; thus, splimp must be >= spltty. 67 */ 68 69#include "sl.h" 70#if NSL > 0 71 72#include "bpfilter.h" 73 74#include <sys/param.h> 75#include <sys/proc.h> 76#include <sys/mbuf.h> 77#include <sys/buf.h> 78#include <sys/dkstat.h> 79#include <sys/socket.h> 80#include <sys/ioctl.h> 81#include <sys/file.h> 82#include <sys/tty.h> 83#include <sys/kernel.h> 84#include <sys/conf.h> 85 86#include <machine/cpu.h> 87 88#include <net/if.h> 89#include <net/if_types.h> 90#include <net/netisr.h> 91#include <net/route.h> 92 93#if INET 94#include <netinet/in.h> 95#include <netinet/in_systm.h> 96#include <netinet/in_var.h> 97#include <netinet/ip.h> 98#else 99Huh? Slip without inet? 100#endif 101 102#include <net/slcompress.h> 103#include <net/if_slvar.h> 104 105#if NBPFILTER > 0 106#include <sys/time.h> 107#include <net/bpf.h> 108#endif 109 110/* 111 * SLMAX is a hard limit on input packet size. To simplify the code 112 * and improve performance, we require that packets fit in an mbuf 113 * cluster, and if we get a compressed packet, there's enough extra 114 * room to expand the header into a max length tcp/ip header (128 115 * bytes). So, SLMAX can be at most 116 * MCLBYTES - 128 117 * 118 * SLMTU is a hard limit on output packet size. To insure good 119 * interactive response, SLMTU wants to be the smallest size that 120 * amortizes the header cost. (Remember that even with 121 * type-of-service queuing, we have to wait for any in-progress 122 * packet to finish. I.e., we wait, on the average, 1/2 * mtu / 123 * cps, where cps is the line speed in characters per second. 124 * E.g., 533ms wait for a 1024 byte MTU on a 9600 baud line. The 125 * average compressed header size is 6-8 bytes so any MTU > 90 126 * bytes will give us 90% of the line bandwidth. A 100ms wait is 127 * tolerable (500ms is not), so want an MTU around 296. (Since TCP 128 * will send 256 byte segments (to allow for 40 byte headers), the 129 * typical packet size on the wire will be around 260 bytes). In 130 * 4.3tahoe+ systems, we can set an MTU in a route so we do that & 131 * leave the interface MTU relatively high (so we don't IP fragment 132 * when acting as a gateway to someone using a stupid MTU). 133 * 134 * Similar considerations apply to SLIP_HIWAT: It's the amount of 135 * data that will be queued 'downstream' of us (i.e., in clists 136 * waiting to be picked up by the tty output interrupt). If we 137 * queue a lot of data downstream, it's immune to our t.o.s. queuing. 138 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 139 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 140 * wait is dependent on the ftp window size but that's typically 141 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 142 * the cost (in idle time on the wire) of the tty driver running 143 * off the end of its clists & having to call back slstart for a 144 * new packet. For a tty interface with any buffering at all, this 145 * cost will be zero. Even with a totally brain dead interface (like 146 * the one on a typical workstation), the cost will be <= 1 character 147 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 148 * at most 1% while maintaining good interactive response. 149 */ 150#if NBPFILTER > 0 151#define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 152#else 153#define BUFOFFSET (128+sizeof(struct ifnet **)) 154#endif 155#define SLMAX (MCLBYTES - BUFOFFSET) 156#define SLBUFSIZE (SLMAX + BUFOFFSET) 157#define SLMTU 296 158#define SLIP_HIWAT roundup(50,CBSIZE) 159#ifndef __NetBSD__ /* XXX - cgd */ 160#define CLISTRESERVE 1024 /* Can't let clists get too low */ 161#endif /* !__NetBSD__ */ 162 163/* 164 * SLIP ABORT ESCAPE MECHANISM: 165 * (inspired by HAYES modem escape arrangement) 166 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 167 * within window time signals a "soft" exit from slip mode by remote end 168 * if the IFF_DEBUG flag is on. 169 */ 170#define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 171#define ABT_IDLE 1 /* in seconds - idle before an escape */ 172#define ABT_COUNT 3 /* count of escapes for abort */ 173#define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 174 175struct sl_softc sl_softc[NSL]; 176 177#define FRAME_END 0xc0 /* Frame End */ 178#define FRAME_ESCAPE 0xdb /* Frame Esc */ 179#define TRANS_FRAME_END 0xdc /* transposed frame end */ 180#define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 181 182extern struct timeval time; 183 184static int slinit __P((struct sl_softc *)); 185static struct mbuf *sl_btom __P((struct sl_softc *, int)); 186 187/* 188 * Called from boot code to establish sl interfaces. 189 */ 190void 191slattach() 192{ 193 register struct sl_softc *sc; 194 register int i = 0; 195 196 for (sc = sl_softc; i < NSL; sc++) { 197 sc->sc_if.if_name = "sl"; 198 sc->sc_if.if_next = NULL; 199 sc->sc_if.if_unit = i++; 200 sc->sc_if.if_mtu = SLMTU; 201#ifdef __NetBSD__ /* XXX - cgd */ 202 sc->sc_if.if_flags = IFF_POINTOPOINT | SC_AUTOCOMP; 203 sc->sc_if.if_flags |= IFF_MULTICAST; 204#else 205 sc->sc_if.if_flags = 206 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 207#endif /* !__NetBSD__ */ 208 sc->sc_if.if_type = IFT_SLIP; 209 sc->sc_if.if_ioctl = slioctl; 210 sc->sc_if.if_output = sloutput; 211 sc->sc_if.if_snd.ifq_maxlen = 50; 212 sc->sc_fastq.ifq_maxlen = 32; 213 if_attach(&sc->sc_if); 214#if NBPFILTER > 0 215 bpfattach(&sc->sc_bpf, &sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 216#endif 217 } 218} 219 220static int 221slinit(sc) 222 register struct sl_softc *sc; 223{ 224 register caddr_t p; 225 226 if (sc->sc_ep == (u_char *) 0) { 227 MCLALLOC(p, M_WAIT); 228 if (p) 229 sc->sc_ep = (u_char *)p + SLBUFSIZE; 230 else { 231 printf("sl%d: can't allocate buffer\n", sc - sl_softc); 232 sc->sc_if.if_flags &= ~IFF_UP; 233 return (0); 234 } 235 } 236 sc->sc_buf = sc->sc_ep - SLMAX; 237 sc->sc_mp = sc->sc_buf; 238 sl_compress_init(&sc->sc_comp); 239 return (1); 240} 241 242/* 243 * Line specific open routine. 244 * Attach the given tty to the first available sl unit. 245 */ 246/* ARGSUSED */ 247int 248slopen(dev, tp) 249 dev_t dev; 250 register struct tty *tp; 251{ 252 struct proc *p = curproc; /* XXX */ 253 register struct sl_softc *sc; 254 register int nsl; 255 int error; 256 257 if (error = suser(p->p_ucred, &p->p_acflag)) 258 return (error); 259 260 if (tp->t_line == SLIPDISC) 261 return (0); 262 263 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 264 if (sc->sc_ttyp == NULL) { 265 if (slinit(sc) == 0) 266 return (ENOBUFS); 267 tp->t_sc = (caddr_t)sc; 268 sc->sc_ttyp = tp; 269 sc->sc_if.if_baudrate = tp->t_ospeed; 270 ttyflush(tp, FREAD | FWRITE); 271 return (0); 272 } 273 return (ENXIO); 274} 275 276/* 277 * Line specific close routine. 278 * Detach the tty from the sl unit. 279 */ 280void 281slclose(tp) 282 struct tty *tp; 283{ 284 register struct sl_softc *sc; 285 int s; 286 287 ttywflush(tp); 288 s = splimp(); /* actually, max(spltty, splnet) */ 289 tp->t_line = 0; 290 sc = (struct sl_softc *)tp->t_sc; 291 if (sc != NULL) { 292 if_down(&sc->sc_if); 293 sc->sc_ttyp = NULL; 294 tp->t_sc = NULL; 295 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE)); 296 sc->sc_ep = 0; 297 sc->sc_mp = 0; 298 sc->sc_buf = 0; 299 } 300 splx(s); 301} 302 303/* 304 * Line specific (tty) ioctl routine. 305 * Provide a way to get the sl unit number. 306 */ 307/* ARGSUSED */ 308int 309sltioctl(tp, cmd, data, flag) 310 struct tty *tp; 311 int cmd; 312 caddr_t data; 313 int flag; 314{ 315 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 316 int s; 317 318 switch (cmd) { 319 case SLIOCGUNIT: 320 *(int *)data = sc->sc_if.if_unit; 321 break; 322 323 default: 324 return (-1); 325 } 326 return (0); 327} 328 329/* 330 * Queue a packet. Start transmission if not active. 331 * Compression happens in slstart; if we do it here, IP TOS 332 * will cause us to not compress "background" packets, because 333 * ordering gets hosed. It can be done for all packets in slstart. 334 */ 335int 336sloutput(ifp, m, dst, rtp) 337 struct ifnet *ifp; 338 register struct mbuf *m; 339 struct sockaddr *dst; 340 struct rtentry *rtp; 341{ 342 register struct sl_softc *sc = &sl_softc[ifp->if_unit]; 343 register struct ip *ip; 344 register struct ifqueue *ifq; 345 int s; 346 347 /* 348 * `Cannot happen' (see slioctl). Someday we will extend 349 * the line protocol to support other address families. 350 */ 351 if (dst->sa_family != AF_INET) { 352 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit, 353 dst->sa_family); 354 m_freem(m); 355 sc->sc_if.if_noproto++; 356 return (EAFNOSUPPORT); 357 } 358 359 if (sc->sc_ttyp == NULL) { 360 m_freem(m); 361 return (ENETDOWN); /* sort of */ 362 } 363 if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0 && 364 (sc->sc_ttyp->t_cflag & CLOCAL) == 0) { 365 m_freem(m); 366 return (EHOSTUNREACH); 367 } 368 ifq = &sc->sc_if.if_snd; 369 ip = mtod(m, struct ip *); 370 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 371 m_freem(m); 372 return (ENETRESET); /* XXX ? */ 373 } 374 if (ip->ip_tos & IPTOS_LOWDELAY) 375 ifq = &sc->sc_fastq; 376 s = splimp(); 377 if (IF_QFULL(ifq)) { 378 IF_DROP(ifq); 379 m_freem(m); 380 splx(s); 381 sc->sc_if.if_oerrors++; 382 return (ENOBUFS); 383 } 384 IF_ENQUEUE(ifq, m); 385 sc->sc_if.if_lastchange = time; 386 if (sc->sc_ttyp->t_outq.c_cc == 0) 387 slstart(sc->sc_ttyp); 388#ifdef __NetBSD__ 389 else /* XXX - cgd */ 390 (*sc->sc_ttyp->t_oproc)(sc->sc_ttyp); 391#endif 392 splx(s); 393 return (0); 394} 395 396/* 397 * Start output on interface. Get another datagram 398 * to send from the interface queue and map it to 399 * the interface before starting output. 400 */ 401void 402slstart(tp) 403 register struct tty *tp; 404{ 405 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 406 register struct mbuf *m; 407 register u_char *cp; 408 register struct ip *ip; 409 int s; 410 struct mbuf *m2; 411#if NBPFILTER > 0 412 u_char bpfbuf[SLMTU + SLIP_HDRLEN]; 413 register int len; 414#endif 415#ifndef __NetBSD__ /* XXX - cgd */ 416 extern int cfreecount; 417#endif 418 419 for (;;) { 420 /* 421 * If there is more in the output queue, just send it now. 422 * We are being called in lieu of ttstart and must do what 423 * it would. 424 */ 425 if (tp->t_outq.c_cc != 0) { 426 (*tp->t_oproc)(tp); 427 if (tp->t_outq.c_cc > SLIP_HIWAT) 428 return; 429 } 430 /* 431 * This happens briefly when the line shuts down. 432 */ 433 if (sc == NULL) 434 return; 435 436#ifdef __NetBSD__ /* XXX - cgd */ 437 /* 438 * Do not remove the packet from the IP queue if it 439 * doesn't look like the packet will fit into the 440 * current serial output queue, with a packet full of 441 * escapes this could be as bad as SLMTU*2. The size 442 * of the ring buffer must be at least SLMTU*2 to 443 * avoid deadlock. 444 */ 445 if (tp->t_outq.c_cn - tp->t_outq.c_cc < 2 * SLMTU) 446 return; 447#endif /* __NetBSD__ */ 448 449 /* 450 * Get a packet and send it to the interface. 451 */ 452 s = splimp(); 453 IF_DEQUEUE(&sc->sc_fastq, m); 454 if (m) 455 sc->sc_if.if_omcasts++; /* XXX */ 456 else 457 IF_DEQUEUE(&sc->sc_if.if_snd, m); 458 splx(s); 459 if (m == NULL) 460 return; 461 462 /* 463 * We do the header compression here rather than in sloutput 464 * because the packets will be out of order if we are using TOS 465 * queueing, and the connection id compression will get 466 * munged when this happens. 467 */ 468#if NBPFILTER > 0 469 if (sc->sc_bpf) { 470 /* 471 * We need to save the TCP/IP header before it's 472 * compressed. To avoid complicated code, we just 473 * copy the entire packet into a stack buffer (since 474 * this is a serial line, packets should be short 475 * and/or the copy should be negligible cost compared 476 * to the packet transmission time). 477 */ 478 register struct mbuf *m1 = m; 479 register u_char *cp = bpfbuf + SLIP_HDRLEN; 480 481 len = 0; 482 do { 483 register int mlen = m1->m_len; 484 485 bcopy(mtod(m1, caddr_t), cp, mlen); 486 cp += mlen; 487 len += mlen; 488 } while (m1 = m1->m_next); 489 } 490#endif 491 if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) { 492 if (sc->sc_if.if_flags & SC_COMPRESS) 493 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 494 &sc->sc_comp, 1); 495 } 496#if NBPFILTER > 0 497 if (sc->sc_bpf) { 498 /* 499 * Put the SLIP pseudo-"link header" in place. The 500 * compressed header is now at the beginning of the 501 * mbuf. 502 */ 503 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 504 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 505 bpf_tap(sc->sc_bpf, bpfbuf, len + SLIP_HDRLEN); 506 } 507#endif 508 sc->sc_if.if_lastchange = time; 509 510#ifndef __NetBSD__ /* XXX - cgd */ 511 /* 512 * If system is getting low on clists, just flush our 513 * output queue (if the stuff was important, it'll get 514 * retransmitted). 515 */ 516 if (cfreecount < CLISTRESERVE + SLMTU) { 517 m_freem(m); 518 sc->sc_if.if_collisions++; 519 continue; 520 } 521#endif /* !__NetBSD__ */ 522 /* 523 * The extra FRAME_END will start up a new packet, and thus 524 * will flush any accumulated garbage. We do this whenever 525 * the line may have been idle for some time. 526 */ 527 if (tp->t_outq.c_cc == 0) { 528 ++sc->sc_if.if_obytes; 529 (void) putc(FRAME_END, &tp->t_outq); 530 } 531 532 while (m) { 533 register u_char *ep; 534 535 cp = mtod(m, u_char *); ep = cp + m->m_len; 536 while (cp < ep) { 537 /* 538 * Find out how many bytes in the string we can 539 * handle without doing something special. 540 */ 541 register u_char *bp = cp; 542 543 while (cp < ep) { 544 switch (*cp++) { 545 case FRAME_ESCAPE: 546 case FRAME_END: 547 --cp; 548 goto out; 549 } 550 } 551 out: 552 if (cp > bp) { 553 /* 554 * Put n characters at once 555 * into the tty output queue. 556 */ 557#ifdef __NetBSD__ /* XXX - cgd */ 558 if (b_to_q((u_char *)bp, cp - bp, 559#else 560 if (b_to_q((char *)bp, cp - bp, 561#endif 562 &tp->t_outq)) 563 break; 564 sc->sc_if.if_obytes += cp - bp; 565 } 566 /* 567 * If there are characters left in the mbuf, 568 * the first one must be special.. 569 * Put it out in a different form. 570 */ 571 if (cp < ep) { 572 if (putc(FRAME_ESCAPE, &tp->t_outq)) 573 break; 574 if (putc(*cp++ == FRAME_ESCAPE ? 575 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 576 &tp->t_outq)) { 577 (void) unputc(&tp->t_outq); 578 break; 579 } 580 sc->sc_if.if_obytes += 2; 581 } 582 } 583 MFREE(m, m2); 584 m = m2; 585 } 586 587 if (putc(FRAME_END, &tp->t_outq)) { 588 /* 589 * Not enough room. Remove a char to make room 590 * and end the packet normally. 591 * If you get many collisions (more than one or two 592 * a day) you probably do not have enough clists 593 * and you should increase "nclist" in param.c. 594 */ 595 (void) unputc(&tp->t_outq); 596 (void) putc(FRAME_END, &tp->t_outq); 597 sc->sc_if.if_collisions++; 598 } else { 599 ++sc->sc_if.if_obytes; 600 sc->sc_if.if_opackets++; 601 } 602 } 603} 604 605/* 606 * Copy data buffer to mbuf chain; add ifnet pointer. 607 */ 608static struct mbuf * 609sl_btom(sc, len) 610 register struct sl_softc *sc; 611 register int len; 612{ 613 register struct mbuf *m; 614 615 MGETHDR(m, M_DONTWAIT, MT_DATA); 616 if (m == NULL) 617 return (NULL); 618 619 /* 620 * If we have more than MHLEN bytes, it's cheaper to 621 * queue the cluster we just filled & allocate a new one 622 * for the input buffer. Otherwise, fill the mbuf we 623 * allocated above. Note that code in the input routine 624 * guarantees that packet will fit in a cluster. 625 */ 626 if (len >= MHLEN) { 627 MCLGET(m, M_DONTWAIT); 628 if ((m->m_flags & M_EXT) == 0) { 629 /* 630 * we couldn't get a cluster - if memory's this 631 * low, it's time to start dropping packets. 632 */ 633 (void) m_free(m); 634 return (NULL); 635 } 636 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 637 m->m_data = (caddr_t)sc->sc_buf; 638 m->m_ext.ext_buf = (caddr_t)((int)sc->sc_buf &~ MCLOFSET); 639 } else 640 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 641 642 m->m_len = len; 643 m->m_pkthdr.len = len; 644 m->m_pkthdr.rcvif = &sc->sc_if; 645 return (m); 646} 647 648/* 649 * tty interface receiver interrupt. 650 */ 651void 652slinput(c, tp) 653 register int c; 654 register struct tty *tp; 655{ 656 register struct sl_softc *sc; 657 register struct mbuf *m; 658 register int len; 659 int s; 660#if NBPFILTER > 0 661 u_char chdr[CHDR_LEN]; 662#endif 663 664 tk_nin++; 665 sc = (struct sl_softc *)tp->t_sc; 666 if (sc == NULL) 667 return; 668 if (c & TTY_ERRORMASK || ((tp->t_state & TS_CARR_ON) == 0 && 669 (tp->t_cflag & CLOCAL) == 0)) { 670 sc->sc_flags |= SC_ERROR; 671 return; 672 } 673 c &= TTY_CHARMASK; 674 675 ++sc->sc_if.if_ibytes; 676 677 if (sc->sc_if.if_flags & IFF_DEBUG) { 678 if (c == ABT_ESC) { 679 /* 680 * If we have a previous abort, see whether 681 * this one is within the time limit. 682 */ 683 if (sc->sc_abortcount && 684 time.tv_sec >= sc->sc_starttime + ABT_WINDOW) 685 sc->sc_abortcount = 0; 686 /* 687 * If we see an abort after "idle" time, count it; 688 * record when the first abort escape arrived. 689 */ 690 if (time.tv_sec >= sc->sc_lasttime + ABT_IDLE) { 691 if (++sc->sc_abortcount == 1) 692 sc->sc_starttime = time.tv_sec; 693 if (sc->sc_abortcount >= ABT_COUNT) { 694 slclose(tp); 695 return; 696 } 697 } 698 } else 699 sc->sc_abortcount = 0; 700 sc->sc_lasttime = time.tv_sec; 701 } 702 703 switch (c) { 704 705 case TRANS_FRAME_ESCAPE: 706 if (sc->sc_escape) 707 c = FRAME_ESCAPE; 708 break; 709 710 case TRANS_FRAME_END: 711 if (sc->sc_escape) 712 c = FRAME_END; 713 break; 714 715 case FRAME_ESCAPE: 716 sc->sc_escape = 1; 717 return; 718 719 case FRAME_END: 720 if(sc->sc_flags & SC_ERROR) { 721 sc->sc_flags &= ~SC_ERROR; 722 goto newpack; 723 } 724 len = sc->sc_mp - sc->sc_buf; 725 if (len < 3) 726 /* less than min length packet - ignore */ 727 goto newpack; 728 729#if NBPFILTER > 0 730 if (sc->sc_bpf) { 731 /* 732 * Save the compressed header, so we 733 * can tack it on later. Note that we 734 * will end up copying garbage in some 735 * cases but this is okay. We remember 736 * where the buffer started so we can 737 * compute the new header length. 738 */ 739 bcopy(sc->sc_buf, chdr, CHDR_LEN); 740 } 741#endif 742 743 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 744 if (c & 0x80) 745 c = TYPE_COMPRESSED_TCP; 746 else if (c == TYPE_UNCOMPRESSED_TCP) 747 *sc->sc_buf &= 0x4f; /* XXX */ 748 /* 749 * We've got something that's not an IP packet. 750 * If compression is enabled, try to decompress it. 751 * Otherwise, if `auto-enable' compression is on and 752 * it's a reasonable packet, decompress it and then 753 * enable compression. Otherwise, drop it. 754 */ 755 if (sc->sc_if.if_flags & SC_COMPRESS) { 756 len = sl_uncompress_tcp(&sc->sc_buf, len, 757 (u_int)c, &sc->sc_comp); 758 if (len <= 0) 759 goto error; 760 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 761 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 762 len = sl_uncompress_tcp(&sc->sc_buf, len, 763 (u_int)c, &sc->sc_comp); 764 if (len <= 0) 765 goto error; 766 sc->sc_if.if_flags |= SC_COMPRESS; 767 } else 768 goto error; 769 } 770#if NBPFILTER > 0 771 if (sc->sc_bpf) { 772 /* 773 * Put the SLIP pseudo-"link header" in place. 774 * We couldn't do this any earlier since 775 * decompression probably moved the buffer 776 * pointer. Then, invoke BPF. 777 */ 778 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 779 780 hp[SLX_DIR] = SLIPDIR_IN; 781 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 782 bpf_tap(sc->sc_bpf, hp, len + SLIP_HDRLEN); 783 } 784#endif 785 m = sl_btom(sc, len); 786 if (m == NULL) 787 goto error; 788 789 sc->sc_if.if_ipackets++; 790 sc->sc_if.if_lastchange = time; 791 s = splimp(); 792 if (IF_QFULL(&ipintrq)) { 793 IF_DROP(&ipintrq); 794 sc->sc_if.if_ierrors++; 795 sc->sc_if.if_iqdrops++; 796 m_freem(m); 797 } else { 798 IF_ENQUEUE(&ipintrq, m); 799 schednetisr(NETISR_IP); 800 } 801 splx(s); 802 goto newpack; 803 } 804 if (sc->sc_mp < sc->sc_ep) { 805 *sc->sc_mp++ = c; 806 sc->sc_escape = 0; 807 return; 808 } 809 810 /* can't put lower; would miss an extra frame */ 811 sc->sc_flags |= SC_ERROR; 812 813error: 814 sc->sc_if.if_ierrors++; 815newpack: 816 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLMAX; 817 sc->sc_escape = 0; 818} 819 820/* 821 * Process an ioctl request. 822 */ 823int 824slioctl(ifp, cmd, data) 825 register struct ifnet *ifp; 826 int cmd; 827 caddr_t data; 828{ 829 register struct ifaddr *ifa = (struct ifaddr *)data; 830 register struct ifreq *ifr; 831 register int s = splimp(), error = 0; 832 833 switch (cmd) { 834 835 case SIOCSIFADDR: 836 if (ifa->ifa_addr->sa_family == AF_INET) 837 ifp->if_flags |= IFF_UP; 838 else 839 error = EAFNOSUPPORT; 840 break; 841 842 case SIOCSIFDSTADDR: 843 if (ifa->ifa_addr->sa_family != AF_INET) 844 error = EAFNOSUPPORT; 845 break; 846 847 case SIOCADDMULTI: 848 case SIOCDELMULTI: 849 ifr = (struct ifreq *)data; 850 if (ifr == 0) { 851 error = EAFNOSUPPORT; /* XXX */ 852 break; 853 } 854 switch (ifr->ifr_addr.sa_family) { 855 856#ifdef INET 857 case AF_INET: 858 break; 859#endif 860 861 default: 862 error = EAFNOSUPPORT; 863 break; 864 } 865 break; 866 867 default: 868 error = EINVAL; 869 } 870 splx(s); 871 return (error); 872} 873#endif 874