if_sl.c revision 1.48
1/* $NetBSD: if_sl.c,v 1.48 1998/03/23 04:41:17 fair Exp $ */ 2 3/* 4 * Copyright (c) 1987, 1989, 1992, 1993 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)if_sl.c 8.9 (Berkeley) 1/9/95 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/malloc.h> 77#include <sys/mbuf.h> 78#include <sys/buf.h> 79#include <sys/dkstat.h> 80#include <sys/socket.h> 81#include <sys/ioctl.h> 82#include <sys/file.h> 83#include <sys/tty.h> 84#include <sys/kernel.h> 85#include <sys/conf.h> 86#if __NetBSD__ 87#include <sys/systm.h> 88#endif 89 90#include <machine/cpu.h> 91 92#include <net/if.h> 93#include <net/if_types.h> 94#include <net/netisr.h> 95#include <net/route.h> 96 97#if INET 98#include <netinet/in.h> 99#include <netinet/in_systm.h> 100#include <netinet/in_var.h> 101#include <netinet/ip.h> 102#else 103Huh? Slip without inet? 104#endif 105 106#include <net/slcompress.h> 107#include <net/if_slvar.h> 108#include <net/slip.h> 109 110#if NBPFILTER > 0 111#include <sys/time.h> 112#include <net/bpf.h> 113#endif 114 115/* 116 * SLMAX is a hard limit on input packet size. To simplify the code 117 * and improve performance, we require that packets fit in an mbuf 118 * cluster, and if we get a compressed packet, there's enough extra 119 * room to expand the header into a max length tcp/ip header (128 120 * bytes). So, SLMAX can be at most 121 * MCLBYTES - 128 122 * 123 * SLMTU is a hard limit on output packet size. To insure good 124 * interactive response, SLMTU wants to be the smallest size that 125 * amortizes the header cost. (Remember that even with 126 * type-of-service queuing, we have to wait for any in-progress 127 * packet to finish. I.e., we wait, on the average, 1/2 * mtu / 128 * cps, where cps is the line speed in characters per second. 129 * E.g., 533ms wait for a 1024 byte MTU on a 9600 baud line. The 130 * average compressed header size is 6-8 bytes so any MTU > 90 131 * bytes will give us 90% of the line bandwidth. A 100ms wait is 132 * tolerable (500ms is not), so want an MTU around 296. (Since TCP 133 * will send 256 byte segments (to allow for 40 byte headers), the 134 * typical packet size on the wire will be around 260 bytes). In 135 * 4.3tahoe+ systems, we can set an MTU in a route so we do that & 136 * leave the interface MTU relatively high (so we don't IP fragment 137 * when acting as a gateway to someone using a stupid MTU). 138 * 139 * Similar considerations apply to SLIP_HIWAT: It's the amount of 140 * data that will be queued 'downstream' of us (i.e., in clists 141 * waiting to be picked up by the tty output interrupt). If we 142 * queue a lot of data downstream, it's immune to our t.o.s. queuing. 143 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 144 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 145 * wait is dependent on the ftp window size but that's typically 146 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 147 * the cost (in idle time on the wire) of the tty driver running 148 * off the end of its clists & having to call back slstart for a 149 * new packet. For a tty interface with any buffering at all, this 150 * cost will be zero. Even with a totally brain dead interface (like 151 * the one on a typical workstation), the cost will be <= 1 character 152 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 153 * at most 1% while maintaining good interactive response. 154 */ 155#if NBPFILTER > 0 156#define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 157#else 158#define BUFOFFSET (128+sizeof(struct ifnet **)) 159#endif 160#define SLMAX (MCLBYTES - BUFOFFSET) 161#define SLBUFSIZE (SLMAX + BUFOFFSET) 162#ifndef SLMTU 163#define SLMTU 296 164#endif 165#if (SLMTU < 3) 166Huh? SLMTU way too small. 167#endif 168#define SLIP_HIWAT roundup(50,CBSIZE) 169#ifndef NetBSD /* XXX - cgd */ 170#define CLISTRESERVE 1024 /* Can't let clists get too low */ 171#endif /* !NetBSD */ 172 173/* 174 * SLIP ABORT ESCAPE MECHANISM: 175 * (inspired by HAYES modem escape arrangement) 176 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 177 * within window time signals a "soft" exit from slip mode by remote end 178 * if the IFF_DEBUG flag is on. 179 */ 180#define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 181#define ABT_IDLE 1 /* in seconds - idle before an escape */ 182#define ABT_COUNT 3 /* count of escapes for abort */ 183#define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 184 185struct sl_softc sl_softc[NSL]; 186 187#define FRAME_END 0xc0 /* Frame End */ 188#define FRAME_ESCAPE 0xdb /* Frame Esc */ 189#define TRANS_FRAME_END 0xdc /* transposed frame end */ 190#define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 191 192static int slinit __P((struct sl_softc *)); 193static struct mbuf *sl_btom __P((struct sl_softc *, int)); 194 195/* 196 * Called from boot code to establish sl interfaces. 197 */ 198void 199slattach() 200{ 201 register struct sl_softc *sc; 202 register int i = 0; 203 204 for (sc = sl_softc; i < NSL; sc++) { 205 sc->sc_unit = i; /* XXX */ 206 sprintf(sc->sc_if.if_xname, "sl%d", i++); 207 sc->sc_if.if_softc = sc; 208 sc->sc_if.if_mtu = SLMTU; 209 sc->sc_if.if_flags = 210 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 211 sc->sc_if.if_type = IFT_SLIP; 212 sc->sc_if.if_ioctl = slioctl; 213 sc->sc_if.if_output = sloutput; 214 sc->sc_if.if_snd.ifq_maxlen = 50; 215 sc->sc_fastq.ifq_maxlen = 32; 216 if_attach(&sc->sc_if); 217#if NBPFILTER > 0 218 bpfattach(&sc->sc_bpf, &sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 219#endif 220 } 221} 222 223static int 224slinit(sc) 225 register struct sl_softc *sc; 226{ 227 228 if (sc->sc_ep == NULL) { 229 /* 230 * XXX the trick this is used for is evil... 231 */ 232 sc->sc_xxx = (u_char *)malloc(MCLBYTES, M_MBUF, M_WAITOK); 233 if (sc->sc_xxx) 234 sc->sc_ep = sc->sc_xxx + SLBUFSIZE; 235 else { 236 printf("sl%d: can't allocate buffer\n", sc->sc_unit); 237 sc->sc_if.if_flags &= ~IFF_UP; 238 return (0); 239 } 240 } 241 sc->sc_buf = sc->sc_ep - SLMAX; 242 sc->sc_mp = sc->sc_buf; 243 sl_compress_init(&sc->sc_comp); 244 return (1); 245} 246 247/* 248 * Line specific open routine. 249 * Attach the given tty to the first available sl unit. 250 */ 251/* ARGSUSED */ 252int 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#ifdef NetBSD 262 int s; 263#endif 264 265 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 266 return (error); 267 268 if (tp->t_line == SLIPDISC) 269 return (0); 270 271 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 272 if (sc->sc_ttyp == NULL) { 273 if (slinit(sc) == 0) 274 return (ENOBUFS); 275 tp->t_sc = (caddr_t)sc; 276 sc->sc_ttyp = tp; 277 sc->sc_if.if_baudrate = tp->t_ospeed; 278 s = spltty(); 279 tp->t_state |= TS_ISOPEN | TS_XCLUDE; 280 splx(s); 281 ttyflush(tp, FREAD | FWRITE); 282#ifdef NetBSD 283 /* 284 * make sure tty output queue is large enough 285 * to hold a full-sized packet (including frame 286 * end, and a possible extra frame end). full-sized 287 * packet occupies a max of 2*SLMTU bytes (because 288 * of possible escapes), and add two on for frame 289 * ends. 290 */ 291 s = spltty(); 292 if (tp->t_outq.c_cn < 2*SLMTU+2) { 293 sc->sc_oldbufsize = tp->t_outq.c_cn; 294 sc->sc_oldbufquot = tp->t_outq.c_cq != 0; 295 296 clfree(&tp->t_outq); 297 error = clalloc(&tp->t_outq, 3*SLMTU, 0); 298 if (error) { 299 splx(s); 300 return(error); 301 } 302 } else 303 sc->sc_oldbufsize = sc->sc_oldbufquot = 0; 304 splx(s); 305#endif /* NetBSD */ 306 return (0); 307 } 308 return (ENXIO); 309} 310 311/* 312 * Line specific close routine. 313 * Detach the tty from the sl unit. 314 */ 315void 316slclose(tp) 317 struct tty *tp; 318{ 319 register struct sl_softc *sc; 320 int s; 321 322 ttywflush(tp); 323 s = splimp(); /* actually, max(spltty, splsoftnet) */ 324 tp->t_line = 0; 325 tp->t_state = 0; 326 sc = (struct sl_softc *)tp->t_sc; 327 if (sc != NULL) { 328 if_down(&sc->sc_if); 329 sc->sc_ttyp = NULL; 330 tp->t_sc = NULL; 331 free((caddr_t)(sc->sc_ep - SLBUFSIZE), M_MBUF); 332 sc->sc_ep = 0; 333 sc->sc_mp = 0; 334 sc->sc_buf = 0; 335 } 336#ifdef NetBSD 337 /* if necessary, install a new outq buffer of the appropriate size */ 338 if (sc->sc_oldbufsize != 0) { 339 clfree(&tp->t_outq); 340 clalloc(&tp->t_outq, sc->sc_oldbufsize, sc->sc_oldbufquot); 341 } 342#endif 343 splx(s); 344} 345 346/* 347 * Line specific (tty) ioctl routine. 348 * Provide a way to get the sl unit number. 349 */ 350/* ARGSUSED */ 351int 352sltioctl(tp, cmd, data, flag) 353 struct tty *tp; 354 u_long cmd; 355 caddr_t data; 356 int flag; 357{ 358 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 359 360 switch (cmd) { 361 case SLIOCGUNIT: 362 *(int *)data = sc->sc_unit; /* XXX */ 363 break; 364 365 default: 366 return (-1); 367 } 368 return (0); 369} 370 371/* 372 * Queue a packet. Start transmission if not active. 373 * Compression happens in slstart; if we do it here, IP TOS 374 * will cause us to not compress "background" packets, because 375 * ordering gets trashed. It can be done for all packets in slstart. 376 */ 377int 378sloutput(ifp, m, dst, rtp) 379 struct ifnet *ifp; 380 register struct mbuf *m; 381 struct sockaddr *dst; 382 struct rtentry *rtp; 383{ 384 register struct sl_softc *sc = ifp->if_softc; 385 register struct ip *ip; 386 register struct ifqueue *ifq; 387 int s; 388 389 /* 390 * `Cannot happen' (see slioctl). Someday we will extend 391 * the line protocol to support other address families. 392 */ 393 if (dst->sa_family != AF_INET) { 394 printf("%s: af%d not supported\n", sc->sc_if.if_xname, 395 dst->sa_family); 396 m_freem(m); 397 sc->sc_if.if_noproto++; 398 return (EAFNOSUPPORT); 399 } 400 401 if (sc->sc_ttyp == NULL) { 402 m_freem(m); 403 return (ENETDOWN); /* sort of */ 404 } 405 if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0 && 406 (sc->sc_ttyp->t_cflag & CLOCAL) == 0) { 407 m_freem(m); 408 printf("%s: no carrier and not local\n" sc->sc_if.if_xname); 409 return (EHOSTUNREACH); 410 } 411 ifq = &sc->sc_if.if_snd; 412 ip = mtod(m, struct ip *); 413 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 414 m_freem(m); 415 return (ENETRESET); /* XXX ? */ 416 } 417 if (ip->ip_tos & IPTOS_LOWDELAY) 418 ifq = &sc->sc_fastq; 419 s = splimp(); 420 if (sc->sc_oqlen && sc->sc_ttyp->t_outq.c_cc == sc->sc_oqlen) { 421 struct timeval tv; 422 423 /* if output's been stalled for too long, and restart */ 424 timersub(&time, &sc->sc_if.if_lastchange, &tv); 425 if (tv.tv_sec > 0) { 426 sc->sc_otimeout++; 427 slstart(sc->sc_ttyp); 428 } 429 } 430 if (IF_QFULL(ifq)) { 431 IF_DROP(ifq); 432 m_freem(m); 433 splx(s); 434 sc->sc_if.if_oerrors++; 435 return (ENOBUFS); 436 } 437 IF_ENQUEUE(ifq, m); 438 sc->sc_if.if_lastchange = time; 439 if ((sc->sc_oqlen = sc->sc_ttyp->t_outq.c_cc) == 0) 440 slstart(sc->sc_ttyp); 441 splx(s); 442 return (0); 443} 444 445/* 446 * Start output on interface. Get another datagram 447 * to send from the interface queue and map it to 448 * the interface before starting output. 449 */ 450void 451slstart(tp) 452 register struct tty *tp; 453{ 454 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 455 register struct mbuf *m; 456 register u_char *cp; 457 register struct ip *ip; 458 int s; 459 struct mbuf *m2; 460#if NBPFILTER > 0 461 u_char bpfbuf[SLMTU + SLIP_HDRLEN]; 462 register int len = 0; 463#endif 464#ifndef NetBSD /* XXX - cgd */ 465 extern int cfreecount; 466#endif 467 468 for (;;) { 469 /* 470 * If there is more in the output queue, just send it now. 471 * We are being called in lieu of ttstart and must do what 472 * it would. 473 */ 474 if (tp->t_outq.c_cc != 0) { 475 (*tp->t_oproc)(tp); 476 if (tp->t_outq.c_cc > SLIP_HIWAT) 477 return; 478 } 479 /* 480 * This happens briefly when the line shuts down. 481 */ 482 if (sc == NULL) 483 return; 484 485#ifdef NetBSD /* XXX - cgd */ 486 /* 487 * Do not remove the packet from the IP queue if it 488 * doesn't look like the packet will fit into the 489 * current serial output queue, with a packet full of 490 * escapes this could be as bad as SLMTU*2+2. 491 */ 492 if (tp->t_outq.c_cn - tp->t_outq.c_cc < 2*SLMTU+2) 493 return; 494#endif /* NetBSD */ 495 496 /* 497 * Get a packet and send it to the interface. 498 */ 499 s = splimp(); 500 IF_DEQUEUE(&sc->sc_fastq, m); 501 if (m) 502 sc->sc_if.if_omcasts++; /* XXX */ 503 else 504 IF_DEQUEUE(&sc->sc_if.if_snd, m); 505 splx(s); 506 if (m == NULL) 507 return; 508 509 /* 510 * We do the header compression here rather than in sloutput 511 * because the packets will be out of order if we are using TOS 512 * queueing, and the connection id compression will get 513 * munged when this happens. 514 */ 515#if NBPFILTER > 0 516 if (sc->sc_bpf) { 517 /* 518 * We need to save the TCP/IP header before it's 519 * compressed. To avoid complicated code, we just 520 * copy the entire packet into a stack buffer (since 521 * this is a serial line, packets should be short 522 * and/or the copy should be negligible cost compared 523 * to the packet transmission time). 524 */ 525 register struct mbuf *m1 = m; 526 register u_char *cp = bpfbuf + SLIP_HDRLEN; 527 528 len = 0; 529 do { 530 register int mlen = m1->m_len; 531 532 bcopy(mtod(m1, caddr_t), cp, mlen); 533 cp += mlen; 534 len += mlen; 535 } while ((m1 = m1->m_next) != NULL); 536 } 537#endif 538 if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) { 539 if (sc->sc_if.if_flags & SC_COMPRESS) 540 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 541 &sc->sc_comp, 1); 542 } 543#if NBPFILTER > 0 544 if (sc->sc_bpf) { 545 /* 546 * Put the SLIP pseudo-"link header" in place. The 547 * compressed header is now at the beginning of the 548 * mbuf. 549 */ 550 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 551 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 552 bpf_tap(sc->sc_bpf, bpfbuf, len + SLIP_HDRLEN); 553 } 554#endif 555 sc->sc_if.if_lastchange = time; 556 557#ifndef __NetBSD__ /* XXX - cgd */ 558 /* 559 * If system is getting low on clists, just flush our 560 * output queue (if the stuff was important, it'll get 561 * retransmitted). 562 */ 563 if (cfreecount < CLISTRESERVE + SLMTU) { 564 m_freem(m); 565 sc->sc_if.if_collisions++; 566 continue; 567 } 568#endif /* !__NetBSD__ */ 569 /* 570 * The extra FRAME_END will start up a new packet, and thus 571 * will flush any accumulated garbage. We do this whenever 572 * the line may have been idle for some time. 573 */ 574 if (tp->t_outq.c_cc == 0) { 575 ++sc->sc_if.if_obytes; 576 (void) putc(FRAME_END, &tp->t_outq); 577 } 578 579 while (m) { 580 register u_char *ep; 581 582 cp = mtod(m, u_char *); ep = cp + m->m_len; 583 while (cp < ep) { 584 /* 585 * Find out how many bytes in the string we can 586 * handle without doing something special. 587 */ 588 register u_char *bp = cp; 589 590 while (cp < ep) { 591 switch (*cp++) { 592 case FRAME_ESCAPE: 593 case FRAME_END: 594 --cp; 595 goto out; 596 } 597 } 598 out: 599 if (cp > bp) { 600 /* 601 * Put n characters at once 602 * into the tty output queue. 603 */ 604#ifdef __NetBSD__ /* XXX - cgd */ 605 if (b_to_q((u_char *)bp, cp - bp, 606#else 607 if (b_to_q((char *)bp, cp - bp, 608#endif 609 &tp->t_outq)) 610 break; 611 sc->sc_if.if_obytes += cp - bp; 612 } 613 /* 614 * If there are characters left in the mbuf, 615 * the first one must be special.. 616 * Put it out in a different form. 617 */ 618 if (cp < ep) { 619 if (putc(FRAME_ESCAPE, &tp->t_outq)) 620 break; 621 if (putc(*cp++ == FRAME_ESCAPE ? 622 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 623 &tp->t_outq)) { 624 (void) unputc(&tp->t_outq); 625 break; 626 } 627 sc->sc_if.if_obytes += 2; 628 } 629 } 630 MFREE(m, m2); 631 m = m2; 632 } 633 634 if (putc(FRAME_END, &tp->t_outq)) { 635 /* 636 * Not enough room. Remove a char to make room 637 * and end the packet normally. 638 * If you get many collisions (more than one or two 639 * a day) you probably do not have enough clists 640 * and you should increase "nclist" in param.c. 641 */ 642 (void) unputc(&tp->t_outq); 643 (void) putc(FRAME_END, &tp->t_outq); 644 sc->sc_if.if_collisions++; 645 } else { 646 ++sc->sc_if.if_obytes; 647 sc->sc_if.if_opackets++; 648 } 649 } 650} 651 652/* 653 * Copy data buffer to mbuf chain; add ifnet pointer. 654 */ 655static struct mbuf * 656sl_btom(sc, len) 657 register struct sl_softc *sc; 658 register int len; 659{ 660 register struct mbuf *m; 661 register u_char *p; 662 663 MGETHDR(m, M_DONTWAIT, MT_DATA); 664 if (m == NULL) 665 return (NULL); 666 667 /* 668 * If we have more than MHLEN bytes, it's cheaper to 669 * queue the cluster we just filled & allocate a new one 670 * for the input buffer. Otherwise, fill the mbuf we 671 * allocated above. Note that code in the input routine 672 * guarantees that packet will fit in a cluster. 673 */ 674 if (len >= MHLEN) { 675 /* 676 * XXX this is that evil trick I mentioned... 677 */ 678 p = sc->sc_xxx; 679 sc->sc_xxx = (u_char *)malloc(MCLBYTES, M_MBUF, M_NOWAIT); 680 if (sc->sc_xxx == NULL) { 681 /* 682 * We couldn't allocate a new buffer - if 683 * memory's this low, it's time to start 684 * dropping packets. 685 */ 686 (void) m_free(m); 687 return (NULL); 688 } 689 sc->sc_ep = sc->sc_xxx + SLBUFSIZE; 690 MEXTADD(m, p, MCLBYTES, M_MBUF, NULL, NULL); 691 m->m_data = (caddr_t)sc->sc_buf; 692 } else 693 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 694 695 m->m_len = len; 696 m->m_pkthdr.len = len; 697 m->m_pkthdr.rcvif = &sc->sc_if; 698 return (m); 699} 700 701/* 702 * tty interface receiver interrupt. 703 */ 704void 705slinput(c, tp) 706 register int c; 707 register struct tty *tp; 708{ 709 register struct sl_softc *sc; 710 register struct mbuf *m; 711 register int len; 712 int s; 713#if NBPFILTER > 0 714 u_char chdr[CHDR_LEN]; 715#endif 716 717 tk_nin++; 718 sc = (struct sl_softc *)tp->t_sc; 719 if (sc == NULL) 720 return; 721 if ((c & TTY_ERRORMASK) || ((tp->t_state & TS_CARR_ON) == 0 && 722 (tp->t_cflag & CLOCAL) == 0)) { 723 sc->sc_flags |= SC_ERROR; 724 return; 725 } 726 c &= TTY_CHARMASK; 727 728 ++sc->sc_if.if_ibytes; 729 730 if (sc->sc_if.if_flags & IFF_DEBUG) { 731 if (c == ABT_ESC) { 732 /* 733 * If we have a previous abort, see whether 734 * this one is within the time limit. 735 */ 736 if (sc->sc_abortcount && 737 time.tv_sec >= sc->sc_starttime + ABT_WINDOW) 738 sc->sc_abortcount = 0; 739 /* 740 * If we see an abort after "idle" time, count it; 741 * record when the first abort escape arrived. 742 */ 743 if (time.tv_sec >= sc->sc_lasttime + ABT_IDLE) { 744 if (++sc->sc_abortcount == 1) 745 sc->sc_starttime = time.tv_sec; 746 if (sc->sc_abortcount >= ABT_COUNT) { 747 slclose(tp); 748 return; 749 } 750 } 751 } else 752 sc->sc_abortcount = 0; 753 sc->sc_lasttime = time.tv_sec; 754 } 755 756 switch (c) { 757 758 case TRANS_FRAME_ESCAPE: 759 if (sc->sc_escape) 760 c = FRAME_ESCAPE; 761 break; 762 763 case TRANS_FRAME_END: 764 if (sc->sc_escape) 765 c = FRAME_END; 766 break; 767 768 case FRAME_ESCAPE: 769 sc->sc_escape = 1; 770 return; 771 772 case FRAME_END: 773 if(sc->sc_flags & SC_ERROR) { 774 sc->sc_flags &= ~SC_ERROR; 775 goto newpack; 776 } 777 len = sc->sc_mp - sc->sc_buf; 778 if (len < 3) 779 /* less than min length packet - ignore */ 780 goto newpack; 781 782#if NBPFILTER > 0 783 if (sc->sc_bpf) { 784 /* 785 * Save the compressed header, so we 786 * can tack it on later. Note that we 787 * will end up copying garbage in some 788 * cases but this is okay. We remember 789 * where the buffer started so we can 790 * compute the new header length. 791 */ 792 bcopy(sc->sc_buf, chdr, CHDR_LEN); 793 } 794#endif 795 796 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 797 if (c & 0x80) 798 c = TYPE_COMPRESSED_TCP; 799 else if (c == TYPE_UNCOMPRESSED_TCP) 800 *sc->sc_buf &= 0x4f; /* XXX */ 801 /* 802 * We've got something that's not an IP packet. 803 * If compression is enabled, try to decompress it. 804 * Otherwise, if `auto-enable' compression is on and 805 * it's a reasonable packet, decompress it and then 806 * enable compression. Otherwise, drop it. 807 */ 808 if (sc->sc_if.if_flags & SC_COMPRESS) { 809 len = sl_uncompress_tcp(&sc->sc_buf, len, 810 (u_int)c, &sc->sc_comp); 811 if (len <= 0) 812 goto error; 813 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 814 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 815 len = sl_uncompress_tcp(&sc->sc_buf, len, 816 (u_int)c, &sc->sc_comp); 817 if (len <= 0) 818 goto error; 819 sc->sc_if.if_flags |= SC_COMPRESS; 820 } else 821 goto error; 822 } 823#if NBPFILTER > 0 824 if (sc->sc_bpf) { 825 /* 826 * Put the SLIP pseudo-"link header" in place. 827 * We couldn't do this any earlier since 828 * decompression probably moved the buffer 829 * pointer. Then, invoke BPF. 830 */ 831 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 832 833 hp[SLX_DIR] = SLIPDIR_IN; 834 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 835 bpf_tap(sc->sc_bpf, hp, len + SLIP_HDRLEN); 836 } 837#endif 838 m = sl_btom(sc, len); 839 if (m == NULL) 840 goto error; 841 842 sc->sc_if.if_ipackets++; 843 sc->sc_if.if_lastchange = time; 844 s = splimp(); 845 if (IF_QFULL(&ipintrq)) { 846 IF_DROP(&ipintrq); 847 sc->sc_if.if_ierrors++; 848 sc->sc_if.if_iqdrops++; 849 m_freem(m); 850 } else { 851 IF_ENQUEUE(&ipintrq, m); 852 schednetisr(NETISR_IP); 853 } 854 splx(s); 855 goto newpack; 856 } 857 if (sc->sc_mp < sc->sc_ep) { 858 *sc->sc_mp++ = c; 859 sc->sc_escape = 0; 860 return; 861 } 862 863 /* can't put lower; would miss an extra frame */ 864 sc->sc_flags |= SC_ERROR; 865 866error: 867 sc->sc_if.if_ierrors++; 868newpack: 869 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLMAX; 870 sc->sc_escape = 0; 871} 872 873/* 874 * Process an ioctl request. 875 */ 876int 877slioctl(ifp, cmd, data) 878 register struct ifnet *ifp; 879 u_long cmd; 880 caddr_t data; 881{ 882 register struct ifaddr *ifa = (struct ifaddr *)data; 883 register struct ifreq *ifr; 884 register int s = splimp(), error = 0; 885 886 switch (cmd) { 887 888 case SIOCSIFADDR: 889 if (ifa->ifa_addr->sa_family == AF_INET) 890 ifp->if_flags |= IFF_UP; 891 else 892 error = EAFNOSUPPORT; 893 break; 894 895 case SIOCSIFDSTADDR: 896 if (ifa->ifa_addr->sa_family != AF_INET) 897 error = EAFNOSUPPORT; 898 break; 899 900 case SIOCADDMULTI: 901 case SIOCDELMULTI: 902 ifr = (struct ifreq *)data; 903 if (ifr == 0) { 904 error = EAFNOSUPPORT; /* XXX */ 905 break; 906 } 907 switch (ifr->ifr_addr.sa_family) { 908 909#ifdef INET 910 case AF_INET: 911 break; 912#endif 913 914 default: 915 error = EAFNOSUPPORT; 916 break; 917 } 918 break; 919 920 default: 921 error = EINVAL; 922 } 923 splx(s); 924 return (error); 925} 926#endif 927