if_sl.c revision 1.45
1/* $NetBSD: if_sl.c,v 1.45 1997/03/27 20:36:14 thorpej 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 8.6 (Berkeley) 2/1/94 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, -1); 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 ttyflush(tp, FREAD | FWRITE); 279#ifdef NetBSD 280 /* 281 * make sure tty output queue is large enough 282 * to hold a full-sized packet (including frame 283 * end, and a possible extra frame end). full-sized 284 * packet occupies a max of 2*SLMTU bytes (because 285 * of possible escapes), and add two on for frame 286 * ends. 287 */ 288 s = spltty(); 289 if (tp->t_outq.c_cn < 2*SLMTU+2) { 290 sc->sc_oldbufsize = tp->t_outq.c_cn; 291 sc->sc_oldbufquot = tp->t_outq.c_cq != 0; 292 293 clfree(&tp->t_outq); 294 error = clalloc(&tp->t_outq, 3*SLMTU, 0); 295 if (error) { 296 splx(s); 297 return(error); 298 } 299 } else 300 sc->sc_oldbufsize = sc->sc_oldbufquot = 0; 301 splx(s); 302#endif /* NetBSD */ 303 return (0); 304 } 305 return (ENXIO); 306} 307 308/* 309 * Line specific close routine. 310 * Detach the tty from the sl unit. 311 */ 312void 313slclose(tp) 314 struct tty *tp; 315{ 316 register struct sl_softc *sc; 317 int s; 318 319 ttywflush(tp); 320 s = splimp(); /* actually, max(spltty, splsoftnet) */ 321 tp->t_line = 0; 322 sc = (struct sl_softc *)tp->t_sc; 323 if (sc != NULL) { 324 if_down(&sc->sc_if); 325 sc->sc_ttyp = NULL; 326 tp->t_sc = NULL; 327 free((caddr_t)(sc->sc_ep - SLBUFSIZE), M_MBUF); 328 sc->sc_ep = 0; 329 sc->sc_mp = 0; 330 sc->sc_buf = 0; 331 } 332#ifdef NetBSD 333 /* if necessary, install a new outq buffer of the appropriate size */ 334 if (sc->sc_oldbufsize != 0) { 335 clfree(&tp->t_outq); 336 clalloc(&tp->t_outq, sc->sc_oldbufsize, sc->sc_oldbufquot); 337 } 338#endif 339 splx(s); 340} 341 342/* 343 * Line specific (tty) ioctl routine. 344 * Provide a way to get the sl unit number. 345 */ 346/* ARGSUSED */ 347int 348sltioctl(tp, cmd, data, flag) 349 struct tty *tp; 350 u_long cmd; 351 caddr_t data; 352 int flag; 353{ 354 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 355 356 switch (cmd) { 357 case SLIOCGUNIT: 358 *(int *)data = sc->sc_unit; /* XXX */ 359 break; 360 361 default: 362 return (-1); 363 } 364 return (0); 365} 366 367/* 368 * Queue a packet. Start transmission if not active. 369 * Compression happens in slstart; if we do it here, IP TOS 370 * will cause us to not compress "background" packets, because 371 * ordering gets trashed. It can be done for all packets in slstart. 372 */ 373int 374sloutput(ifp, m, dst, rtp) 375 struct ifnet *ifp; 376 register struct mbuf *m; 377 struct sockaddr *dst; 378 struct rtentry *rtp; 379{ 380 register struct sl_softc *sc = ifp->if_softc; 381 register struct ip *ip; 382 register struct ifqueue *ifq; 383 int s; 384 385 /* 386 * `Cannot happen' (see slioctl). Someday we will extend 387 * the line protocol to support other address families. 388 */ 389 if (dst->sa_family != AF_INET) { 390 printf("%s: af%d not supported\n", sc->sc_if.if_xname, 391 dst->sa_family); 392 m_freem(m); 393 sc->sc_if.if_noproto++; 394 return (EAFNOSUPPORT); 395 } 396 397 if (sc->sc_ttyp == NULL) { 398 m_freem(m); 399 return (ENETDOWN); /* sort of */ 400 } 401 if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0 && 402 (sc->sc_ttyp->t_cflag & CLOCAL) == 0) { 403 m_freem(m); 404 return (EHOSTUNREACH); 405 } 406 ifq = &sc->sc_if.if_snd; 407 ip = mtod(m, struct ip *); 408 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 409 m_freem(m); 410 return (ENETRESET); /* XXX ? */ 411 } 412 if (ip->ip_tos & IPTOS_LOWDELAY) 413 ifq = &sc->sc_fastq; 414 s = splimp(); 415 if (sc->sc_oqlen && sc->sc_ttyp->t_outq.c_cc == sc->sc_oqlen) { 416 struct timeval tv; 417 418 /* if output's been stalled for too long, and restart */ 419 timersub(&time, &sc->sc_if.if_lastchange, &tv); 420 if (tv.tv_sec > 0) { 421 sc->sc_otimeout++; 422 slstart(sc->sc_ttyp); 423 } 424 } 425 if (IF_QFULL(ifq)) { 426 IF_DROP(ifq); 427 m_freem(m); 428 splx(s); 429 sc->sc_if.if_oerrors++; 430 return (ENOBUFS); 431 } 432 IF_ENQUEUE(ifq, m); 433 sc->sc_if.if_lastchange = time; 434 if ((sc->sc_oqlen = sc->sc_ttyp->t_outq.c_cc) == 0) 435 slstart(sc->sc_ttyp); 436 splx(s); 437 return (0); 438} 439 440/* 441 * Start output on interface. Get another datagram 442 * to send from the interface queue and map it to 443 * the interface before starting output. 444 */ 445void 446slstart(tp) 447 register struct tty *tp; 448{ 449 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 450 register struct mbuf *m; 451 register u_char *cp; 452 register struct ip *ip; 453 int s; 454 struct mbuf *m2; 455#if NBPFILTER > 0 456 u_char bpfbuf[SLMTU + SLIP_HDRLEN]; 457 register int len = 0; 458#endif 459#ifndef NetBSD /* XXX - cgd */ 460 extern int cfreecount; 461#endif 462 463 for (;;) { 464 /* 465 * If there is more in the output queue, just send it now. 466 * We are being called in lieu of ttstart and must do what 467 * it would. 468 */ 469 if (tp->t_outq.c_cc != 0) { 470 (*tp->t_oproc)(tp); 471 if (tp->t_outq.c_cc > SLIP_HIWAT) 472 return; 473 } 474 /* 475 * This happens briefly when the line shuts down. 476 */ 477 if (sc == NULL) 478 return; 479 480#ifdef NetBSD /* XXX - cgd */ 481 /* 482 * Do not remove the packet from the IP queue if it 483 * doesn't look like the packet will fit into the 484 * current serial output queue, with a packet full of 485 * escapes this could be as bad as SLMTU*2+2. 486 */ 487 if (tp->t_outq.c_cn - tp->t_outq.c_cc < 2*SLMTU+2) 488 return; 489#endif /* NetBSD */ 490 491 /* 492 * Get a packet and send it to the interface. 493 */ 494 s = splimp(); 495 IF_DEQUEUE(&sc->sc_fastq, m); 496 if (m) 497 sc->sc_if.if_omcasts++; /* XXX */ 498 else 499 IF_DEQUEUE(&sc->sc_if.if_snd, m); 500 splx(s); 501 if (m == NULL) 502 return; 503 504 /* 505 * We do the header compression here rather than in sloutput 506 * because the packets will be out of order if we are using TOS 507 * queueing, and the connection id compression will get 508 * munged when this happens. 509 */ 510#if NBPFILTER > 0 511 if (sc->sc_bpf) { 512 /* 513 * We need to save the TCP/IP header before it's 514 * compressed. To avoid complicated code, we just 515 * copy the entire packet into a stack buffer (since 516 * this is a serial line, packets should be short 517 * and/or the copy should be negligible cost compared 518 * to the packet transmission time). 519 */ 520 register struct mbuf *m1 = m; 521 register u_char *cp = bpfbuf + SLIP_HDRLEN; 522 523 len = 0; 524 do { 525 register int mlen = m1->m_len; 526 527 bcopy(mtod(m1, caddr_t), cp, mlen); 528 cp += mlen; 529 len += mlen; 530 } while ((m1 = m1->m_next) != NULL); 531 } 532#endif 533 if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) { 534 if (sc->sc_if.if_flags & SC_COMPRESS) 535 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 536 &sc->sc_comp, 1); 537 } 538#if NBPFILTER > 0 539 if (sc->sc_bpf) { 540 /* 541 * Put the SLIP pseudo-"link header" in place. The 542 * compressed header is now at the beginning of the 543 * mbuf. 544 */ 545 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 546 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 547 bpf_tap(sc->sc_bpf, bpfbuf, len + SLIP_HDRLEN); 548 } 549#endif 550 sc->sc_if.if_lastchange = time; 551 552#ifndef __NetBSD__ /* XXX - cgd */ 553 /* 554 * If system is getting low on clists, just flush our 555 * output queue (if the stuff was important, it'll get 556 * retransmitted). 557 */ 558 if (cfreecount < CLISTRESERVE + SLMTU) { 559 m_freem(m); 560 sc->sc_if.if_collisions++; 561 continue; 562 } 563#endif /* !__NetBSD__ */ 564 /* 565 * The extra FRAME_END will start up a new packet, and thus 566 * will flush any accumulated garbage. We do this whenever 567 * the line may have been idle for some time. 568 */ 569 if (tp->t_outq.c_cc == 0) { 570 ++sc->sc_if.if_obytes; 571 (void) putc(FRAME_END, &tp->t_outq); 572 } 573 574 while (m) { 575 register u_char *ep; 576 577 cp = mtod(m, u_char *); ep = cp + m->m_len; 578 while (cp < ep) { 579 /* 580 * Find out how many bytes in the string we can 581 * handle without doing something special. 582 */ 583 register u_char *bp = cp; 584 585 while (cp < ep) { 586 switch (*cp++) { 587 case FRAME_ESCAPE: 588 case FRAME_END: 589 --cp; 590 goto out; 591 } 592 } 593 out: 594 if (cp > bp) { 595 /* 596 * Put n characters at once 597 * into the tty output queue. 598 */ 599#ifdef __NetBSD__ /* XXX - cgd */ 600 if (b_to_q((u_char *)bp, cp - bp, 601#else 602 if (b_to_q((char *)bp, cp - bp, 603#endif 604 &tp->t_outq)) 605 break; 606 sc->sc_if.if_obytes += cp - bp; 607 } 608 /* 609 * If there are characters left in the mbuf, 610 * the first one must be special.. 611 * Put it out in a different form. 612 */ 613 if (cp < ep) { 614 if (putc(FRAME_ESCAPE, &tp->t_outq)) 615 break; 616 if (putc(*cp++ == FRAME_ESCAPE ? 617 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 618 &tp->t_outq)) { 619 (void) unputc(&tp->t_outq); 620 break; 621 } 622 sc->sc_if.if_obytes += 2; 623 } 624 } 625 MFREE(m, m2); 626 m = m2; 627 } 628 629 if (putc(FRAME_END, &tp->t_outq)) { 630 /* 631 * Not enough room. Remove a char to make room 632 * and end the packet normally. 633 * If you get many collisions (more than one or two 634 * a day) you probably do not have enough clists 635 * and you should increase "nclist" in param.c. 636 */ 637 (void) unputc(&tp->t_outq); 638 (void) putc(FRAME_END, &tp->t_outq); 639 sc->sc_if.if_collisions++; 640 } else { 641 ++sc->sc_if.if_obytes; 642 sc->sc_if.if_opackets++; 643 } 644 } 645} 646 647/* 648 * Copy data buffer to mbuf chain; add ifnet pointer. 649 */ 650static struct mbuf * 651sl_btom(sc, len) 652 register struct sl_softc *sc; 653 register int len; 654{ 655 register struct mbuf *m; 656 register u_char *p; 657 658 MGETHDR(m, M_DONTWAIT, MT_DATA); 659 if (m == NULL) 660 return (NULL); 661 662 /* 663 * If we have more than MHLEN bytes, it's cheaper to 664 * queue the cluster we just filled & allocate a new one 665 * for the input buffer. Otherwise, fill the mbuf we 666 * allocated above. Note that code in the input routine 667 * guarantees that packet will fit in a cluster. 668 */ 669 if (len >= MHLEN) { 670 /* 671 * XXX this is that evil trick I mentioned... 672 */ 673 p = sc->sc_xxx; 674 sc->sc_xxx = (u_char *)malloc(MCLBYTES, M_MBUF, M_NOWAIT); 675 if (sc->sc_xxx == NULL) { 676 /* 677 * We couldn't allocate a new buffer - if 678 * memory's this low, it's time to start 679 * dropping packets. 680 */ 681 (void) m_free(m); 682 return (NULL); 683 } 684 sc->sc_ep = sc->sc_xxx + SLBUFSIZE; 685 MEXTADD(m, p, MCLBYTES, M_MBUF, NULL, NULL); 686 m->m_data = (caddr_t)sc->sc_buf; 687 } else 688 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 689 690 m->m_len = len; 691 m->m_pkthdr.len = len; 692 m->m_pkthdr.rcvif = &sc->sc_if; 693 return (m); 694} 695 696/* 697 * tty interface receiver interrupt. 698 */ 699void 700slinput(c, tp) 701 register int c; 702 register struct tty *tp; 703{ 704 register struct sl_softc *sc; 705 register struct mbuf *m; 706 register int len; 707 int s; 708#if NBPFILTER > 0 709 u_char chdr[CHDR_LEN]; 710#endif 711 712 tk_nin++; 713 sc = (struct sl_softc *)tp->t_sc; 714 if (sc == NULL) 715 return; 716 if (c & TTY_ERRORMASK || ((tp->t_state & TS_CARR_ON) == 0 && 717 (tp->t_cflag & CLOCAL) == 0)) { 718 sc->sc_flags |= SC_ERROR; 719 return; 720 } 721 c &= TTY_CHARMASK; 722 723 ++sc->sc_if.if_ibytes; 724 725 if (sc->sc_if.if_flags & IFF_DEBUG) { 726 if (c == ABT_ESC) { 727 /* 728 * If we have a previous abort, see whether 729 * this one is within the time limit. 730 */ 731 if (sc->sc_abortcount && 732 time.tv_sec >= sc->sc_starttime + ABT_WINDOW) 733 sc->sc_abortcount = 0; 734 /* 735 * If we see an abort after "idle" time, count it; 736 * record when the first abort escape arrived. 737 */ 738 if (time.tv_sec >= sc->sc_lasttime + ABT_IDLE) { 739 if (++sc->sc_abortcount == 1) 740 sc->sc_starttime = time.tv_sec; 741 if (sc->sc_abortcount >= ABT_COUNT) { 742 slclose(tp); 743 return; 744 } 745 } 746 } else 747 sc->sc_abortcount = 0; 748 sc->sc_lasttime = time.tv_sec; 749 } 750 751 switch (c) { 752 753 case TRANS_FRAME_ESCAPE: 754 if (sc->sc_escape) 755 c = FRAME_ESCAPE; 756 break; 757 758 case TRANS_FRAME_END: 759 if (sc->sc_escape) 760 c = FRAME_END; 761 break; 762 763 case FRAME_ESCAPE: 764 sc->sc_escape = 1; 765 return; 766 767 case FRAME_END: 768 if(sc->sc_flags & SC_ERROR) { 769 sc->sc_flags &= ~SC_ERROR; 770 goto newpack; 771 } 772 len = sc->sc_mp - sc->sc_buf; 773 if (len < 3) 774 /* less than min length packet - ignore */ 775 goto newpack; 776 777#if NBPFILTER > 0 778 if (sc->sc_bpf) { 779 /* 780 * Save the compressed header, so we 781 * can tack it on later. Note that we 782 * will end up copying garbage in some 783 * cases but this is okay. We remember 784 * where the buffer started so we can 785 * compute the new header length. 786 */ 787 bcopy(sc->sc_buf, chdr, CHDR_LEN); 788 } 789#endif 790 791 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 792 if (c & 0x80) 793 c = TYPE_COMPRESSED_TCP; 794 else if (c == TYPE_UNCOMPRESSED_TCP) 795 *sc->sc_buf &= 0x4f; /* XXX */ 796 /* 797 * We've got something that's not an IP packet. 798 * If compression is enabled, try to decompress it. 799 * Otherwise, if `auto-enable' compression is on and 800 * it's a reasonable packet, decompress it and then 801 * enable compression. Otherwise, drop it. 802 */ 803 if (sc->sc_if.if_flags & SC_COMPRESS) { 804 len = sl_uncompress_tcp(&sc->sc_buf, len, 805 (u_int)c, &sc->sc_comp); 806 if (len <= 0) 807 goto error; 808 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 809 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 810 len = sl_uncompress_tcp(&sc->sc_buf, len, 811 (u_int)c, &sc->sc_comp); 812 if (len <= 0) 813 goto error; 814 sc->sc_if.if_flags |= SC_COMPRESS; 815 } else 816 goto error; 817 } 818#if NBPFILTER > 0 819 if (sc->sc_bpf) { 820 /* 821 * Put the SLIP pseudo-"link header" in place. 822 * We couldn't do this any earlier since 823 * decompression probably moved the buffer 824 * pointer. Then, invoke BPF. 825 */ 826 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 827 828 hp[SLX_DIR] = SLIPDIR_IN; 829 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 830 bpf_tap(sc->sc_bpf, hp, len + SLIP_HDRLEN); 831 } 832#endif 833 m = sl_btom(sc, len); 834 if (m == NULL) 835 goto error; 836 837 sc->sc_if.if_ipackets++; 838 sc->sc_if.if_lastchange = time; 839 s = splimp(); 840 if (IF_QFULL(&ipintrq)) { 841 IF_DROP(&ipintrq); 842 sc->sc_if.if_ierrors++; 843 sc->sc_if.if_iqdrops++; 844 m_freem(m); 845 } else { 846 IF_ENQUEUE(&ipintrq, m); 847 schednetisr(NETISR_IP); 848 } 849 splx(s); 850 goto newpack; 851 } 852 if (sc->sc_mp < sc->sc_ep) { 853 *sc->sc_mp++ = c; 854 sc->sc_escape = 0; 855 return; 856 } 857 858 /* can't put lower; would miss an extra frame */ 859 sc->sc_flags |= SC_ERROR; 860 861error: 862 sc->sc_if.if_ierrors++; 863newpack: 864 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLMAX; 865 sc->sc_escape = 0; 866} 867 868/* 869 * Process an ioctl request. 870 */ 871int 872slioctl(ifp, cmd, data) 873 register struct ifnet *ifp; 874 u_long cmd; 875 caddr_t data; 876{ 877 register struct ifaddr *ifa = (struct ifaddr *)data; 878 register struct ifreq *ifr; 879 register int s = splimp(), error = 0; 880 881 switch (cmd) { 882 883 case SIOCSIFADDR: 884 if (ifa->ifa_addr->sa_family == AF_INET) 885 ifp->if_flags |= IFF_UP; 886 else 887 error = EAFNOSUPPORT; 888 break; 889 890 case SIOCSIFDSTADDR: 891 if (ifa->ifa_addr->sa_family != AF_INET) 892 error = EAFNOSUPPORT; 893 break; 894 895 case SIOCADDMULTI: 896 case SIOCDELMULTI: 897 ifr = (struct ifreq *)data; 898 if (ifr == 0) { 899 error = EAFNOSUPPORT; /* XXX */ 900 break; 901 } 902 switch (ifr->ifr_addr.sa_family) { 903 904#ifdef INET 905 case AF_INET: 906 break; 907#endif 908 909 default: 910 error = EAFNOSUPPORT; 911 break; 912 } 913 break; 914 915 default: 916 error = EINVAL; 917 } 918 splx(s); 919 return (error); 920} 921#endif 922