Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/net/if_sl.c
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1 /* 2 * Copyright (c) 1987, 1989, 1992, 1993 3 * The Regents of the University of California. 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 * @(#)if_sl.c 8.6 (Berkeley) 2/1/94 34 * $FreeBSD: src/sys/net/if_sl.c,v 1.45.2.4 1999/09/05 08:17:46 peter Exp $ 35 */ 36 37 /* 38 * Serial Line interface 39 * 40 * Rick Adams 41 * Center for Seismic Studies 42 * 1300 N 17th Street, Suite 1450 43 * Arlington, Virginia 22209 44 * (703)276-7900 45 * rick@seismo.ARPA 46 * seismo!rick 47 * 48 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). 49 * N.B.: this belongs in netinet, not net, the way it stands now. 50 * Should have a link-layer type designation, but wouldn't be 51 * backwards-compatible. 52 * 53 * Converted to 4.3BSD Beta by Chris Torek. 54 * Other changes made at Berkeley, based in part on code by Kirk Smith. 55 * W. Jolitz added slip abort. 56 * 57 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov). 58 * Added priority queuing for "interactive" traffic; hooks for TCP 59 * header compression; ICMP filtering (at 2400 baud, some cretin 60 * pinging you can use up all your bandwidth). Made low clist behavior 61 * more robust and slightly less likely to hang serial line. 62 * Sped up a bunch of things. 63 * 64 * Note that splimp() is used throughout to block both (tty) input 65 * interrupts and network activity; thus, splimp must be >= spltty. 66 */ 67 68 #include "sl.h" 69 #if NSL > 0 70 71 #include "bpfilter.h" 72 73 #include <sys/param.h> 74 #include <sys/systm.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/signalvar.h> 84 #include <sys/tty.h> 85 #include <sys/clist.h> 86 #include <sys/kernel.h> 87 #include <sys/conf.h> 88 89 #include <net/if.h> 90 #include <net/if_types.h> 91 #include <net/netisr.h> 92 #include <net/route.h> 93 94 #if INET 95 #include <netinet/in.h> 96 #include <netinet/in_systm.h> 97 #include <netinet/in_var.h> 98 #include <netinet/ip.h> 99 #else 100 Huh? Slip without inet? 101 #endif 102 103 #include <net/slcompress.h> 104 #include <net/if_slvar.h> 105 #include <net/slip.h> 106 107 #if NBPFILTER > 0 108 #include <sys/time.h> 109 #include <net/bpf.h> 110 #endif 111 112 static void slattach __P((void *)); 113 PSEUDO_SET(slattach, if_sl); 114 115 /* 116 * SLRMAX 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, SLRMAX can be at most 121 * MCLBYTES - 128 122 * 123 * SLMTU is the default transmit MTU. The transmit MTU should be kept 124 * small enough so that interactive use doesn't suffer, but large 125 * enough to provide good performance. 552 is a good choice for SLMTU 126 * because it is high enough to not fragment TCP packets being routed 127 * through this host. Packet fragmentation is bad with SLIP because 128 * fragment headers aren't compressed. The previous assumptions about 129 * the best MTU value don't really hold when using modern modems with 130 * BTLZ data compression because the modem buffers play a much larger 131 * role in interactive performance than the MTU. The MTU can be changed 132 * at any time to suit the specific environment with ifconfig(8), and 133 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 134 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 135 * handles this better). 136 * 137 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 138 * of us (i.e., in clists waiting to be picked up by the tty output 139 * interrupt). If we queue a lot of data downstream, it's immune to 140 * our t.o.s. queuing. 141 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 142 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 143 * wait is dependent on the ftp window size but that's typically 144 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 145 * the cost (in idle time on the wire) of the tty driver running 146 * off the end of its clists & having to call back slstart for a 147 * new packet. For a tty interface with any buffering at all, this 148 * cost will be zero. Even with a totally brain dead interface (like 149 * the one on a typical workstation), the cost will be <= 1 character 150 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 151 * at most 1% while maintaining good interactive response. 152 */ 153 #if NBPFILTER > 0 154 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 155 #else 156 #define BUFOFFSET (128+sizeof(struct ifnet **)) 157 #endif 158 #define SLRMAX (MCLBYTES - BUFOFFSET) 159 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 160 #ifndef SLMTU 161 #define SLMTU 552 /* default MTU */ 162 #endif 163 #define SLTMAX 1500 /* maximum MTU */ 164 #define SLIP_HIWAT roundup(50,CBSIZE) 165 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 166 167 /* 168 * SLIP ABORT ESCAPE MECHANISM: 169 * (inspired by HAYES modem escape arrangement) 170 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 171 * within window time signals a "soft" exit from slip mode by remote end 172 * if the IFF_DEBUG flag is on. 173 */ 174 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 175 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 176 #define ABT_COUNT 3 /* count of escapes for abort */ 177 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 178 179 struct sl_softc sl_softc[NSL]; 180 181 #define FRAME_END 0xc0 /* Frame End */ 182 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 183 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 184 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 185 186 static int slinit __P((struct sl_softc *)); 187 static struct mbuf *sl_btom __P((struct sl_softc *, int)); 188 static timeout_t sl_keepalive; 189 static timeout_t sl_outfill; 190 static int slclose __P((struct tty *,int)); 191 static int slinput __P((int, struct tty *)); 192 static int slioctl __P((struct ifnet *, int, caddr_t)); 193 static int sltioctl __P((struct tty *, int, caddr_t, int, struct proc *)); 194 static int slopen __P((dev_t, struct tty *)); 195 static int sloutput __P((struct ifnet *, 196 struct mbuf *, struct sockaddr *, struct rtentry *)); 197 static int slstart __P((struct tty *)); 198 199 static struct linesw slipdisc = { 200 slopen, slclose, l_noread, l_nowrite, 201 sltioctl, slinput, slstart, ttymodem 202 }; 203 204 /* 205 * Called from boot code to establish sl interfaces. 206 */ 207 static void 208 slattach(dummy) 209 void *dummy; 210 { 211 register struct sl_softc *sc; 212 register int i = 0; 213 214 linesw[SLIPDISC] = slipdisc; 215 216 for (sc = sl_softc; i < NSL; sc++) { 217 sc->sc_if.if_name = "sl"; 218 sc->sc_if.if_next = NULL; 219 sc->sc_if.if_unit = i++; 220 sc->sc_if.if_mtu = SLMTU; 221 sc->sc_if.if_flags = 222 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 223 sc->sc_if.if_type = IFT_SLIP; 224 sc->sc_if.if_ioctl = slioctl; 225 sc->sc_if.if_output = sloutput; 226 sc->sc_if.if_snd.ifq_maxlen = 50; 227 sc->sc_fastq.ifq_maxlen = 32; 228 sc->sc_if.if_linkmib = sc; 229 sc->sc_if.if_linkmiblen = sizeof *sc; 230 if_attach(&sc->sc_if); 231 #if NBPFILTER > 0 232 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 233 #endif 234 } 235 } 236 237 static int 238 slinit(sc) 239 register struct sl_softc *sc; 240 { 241 register caddr_t p; 242 243 if (sc->sc_ep == (u_char *) 0) { 244 MCLALLOC(p, M_WAIT); 245 if (p) 246 sc->sc_ep = (u_char *)p + SLBUFSIZE; 247 else { 248 printf("sl%d: can't allocate buffer\n", sc - sl_softc); 249 return (0); 250 } 251 } 252 sc->sc_buf = sc->sc_ep - SLRMAX; 253 sc->sc_mp = sc->sc_buf; 254 sl_compress_init(&sc->sc_comp, -1); 255 return (1); 256 } 257 258 /* 259 * Line specific open routine. 260 * Attach the given tty to the first available sl unit. 261 */ 262 /* ARGSUSED */ 263 static int 264 slopen(dev, tp) 265 dev_t dev; 266 register struct tty *tp; 267 { 268 struct proc *p = curproc; /* XXX */ 269 register struct sl_softc *sc; 270 register int nsl; 271 int s, error; 272 273 error = suser(p->p_ucred, &p->p_acflag); 274 if (error) 275 return (error); 276 277 if (tp->t_line == SLIPDISC) 278 return (0); 279 280 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 281 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) { 282 if (slinit(sc) == 0) 283 return (ENOBUFS); 284 tp->t_sc = (caddr_t)sc; 285 sc->sc_ttyp = tp; 286 sc->sc_if.if_baudrate = tp->t_ospeed; 287 ttyflush(tp, FREAD | FWRITE); 288 289 tp->t_line = SLIPDISC; 290 /* 291 * We don't use t_canq or t_rawq, so reduce their 292 * cblock resources to 0. Reserve enough cblocks 293 * for t_outq to guarantee that we can fit a full 294 * packet if the SLIP_HIWAT check allows slstart() 295 * to loop. Use the same value for the cblock 296 * limit since the reserved blocks should always 297 * be enough. Reserving cblocks probably makes 298 * the CLISTRESERVE check unnecessary and wasteful. 299 */ 300 clist_alloc_cblocks(&tp->t_canq, 0, 0); 301 clist_alloc_cblocks(&tp->t_outq, 302 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 303 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 304 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 305 306 s = splnet(); 307 if_up(&sc->sc_if); 308 splx(s); 309 return (0); 310 } 311 return (ENXIO); 312 } 313 314 /* 315 * Line specific close routine. 316 * Detach the tty from the sl unit. 317 */ 318 static int 319 slclose(tp,flag) 320 struct tty *tp; 321 int flag; 322 { 323 register struct sl_softc *sc; 324 int s; 325 326 ttyflush(tp, FREAD | FWRITE); 327 /* 328 * XXX the placement of the following spl is misleading. tty 329 * interrupts must be blocked across line discipline switches 330 * and throughout closes to avoid races. 331 */ 332 s = splimp(); /* actually, max(spltty, splnet) */ 333 clist_free_cblocks(&tp->t_outq); 334 tp->t_line = 0; 335 sc = (struct sl_softc *)tp->t_sc; 336 if (sc != NULL) { 337 if (sc->sc_outfill) { 338 sc->sc_outfill = 0; 339 untimeout(sl_outfill, sc); 340 } 341 if (sc->sc_keepalive) { 342 sc->sc_keepalive = 0; 343 untimeout(sl_keepalive, sc); 344 } 345 if_down(&sc->sc_if); 346 sc->sc_flags &= SC_STATIC; 347 sc->sc_ttyp = NULL; 348 tp->t_sc = NULL; 349 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE)); 350 sc->sc_ep = 0; 351 sc->sc_mp = 0; 352 sc->sc_buf = 0; 353 } 354 splx(s); 355 return 0; 356 } 357 358 /* 359 * Line specific (tty) ioctl routine. 360 * Provide a way to get the sl unit number. 361 */ 362 /* ARGSUSED */ 363 static int 364 sltioctl(tp, cmd, data, flag, p) 365 struct tty *tp; 366 int cmd; 367 caddr_t data; 368 int flag; 369 struct proc *p; 370 { 371 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc; 372 int s, nsl; 373 374 s = splimp(); 375 switch (cmd) { 376 case SLIOCGUNIT: 377 *(int *)data = sc->sc_if.if_unit; 378 break; 379 380 case SLIOCSUNIT: 381 if (sc->sc_if.if_unit != *(u_int *)data) { 382 for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) { 383 if ( nc->sc_if.if_unit == *(u_int *)data 384 && nc->sc_ttyp == NULL 385 ) { 386 tmpnc = malloc(sizeof *tmpnc, M_TEMP, 387 M_WAITOK); 388 *tmpnc = *nc; 389 *nc = *sc; 390 nc->sc_if = tmpnc->sc_if; 391 tmpnc->sc_if = sc->sc_if; 392 *sc = *tmpnc; 393 free(tmpnc, M_TEMP); 394 if (sc->sc_if.if_flags & IFF_UP) { 395 if_down(&sc->sc_if); 396 if (!(nc->sc_if.if_flags & IFF_UP)) 397 if_up(&nc->sc_if); 398 } else if (nc->sc_if.if_flags & IFF_UP) 399 if_down(&nc->sc_if); 400 sc->sc_flags &= ~SC_STATIC; 401 sc->sc_flags |= (nc->sc_flags & SC_STATIC); 402 tp->t_sc = sc = nc; 403 goto slfound; 404 } 405 } 406 splx(s); 407 return (ENXIO); 408 } 409 slfound: 410 sc->sc_flags |= SC_STATIC; 411 break; 412 413 case SLIOCSKEEPAL: 414 sc->sc_keepalive = *(u_int *)data * hz; 415 if (sc->sc_keepalive) { 416 sc->sc_flags |= SC_KEEPALIVE; 417 timeout(sl_keepalive, sc, sc->sc_keepalive); 418 } else { 419 sc->sc_flags &= ~SC_KEEPALIVE; 420 untimeout(sl_keepalive, sc); 421 } 422 break; 423 424 case SLIOCGKEEPAL: 425 *(int *)data = sc->sc_keepalive / hz; 426 break; 427 428 case SLIOCSOUTFILL: 429 sc->sc_outfill = *(u_int *)data * hz; 430 if (sc->sc_outfill) { 431 sc->sc_flags |= SC_OUTWAIT; 432 timeout(sl_outfill, sc, sc->sc_outfill); 433 } else { 434 sc->sc_flags &= ~SC_OUTWAIT; 435 untimeout(sl_outfill, sc); 436 } 437 break; 438 439 case SLIOCGOUTFILL: 440 *(int *)data = sc->sc_outfill / hz; 441 break; 442 443 default: 444 splx(s); 445 return (-1); 446 } 447 splx(s); 448 return (0); 449 } 450 451 /* 452 * Queue a packet. Start transmission if not active. 453 * Compression happens in slstart; if we do it here, IP TOS 454 * will cause us to not compress "background" packets, because 455 * ordering gets trashed. It can be done for all packets in slstart. 456 */ 457 static int 458 sloutput(ifp, m, dst, rtp) 459 struct ifnet *ifp; 460 register struct mbuf *m; 461 struct sockaddr *dst; 462 struct rtentry *rtp; 463 { 464 register struct sl_softc *sc = &sl_softc[ifp->if_unit]; 465 register struct ip *ip; 466 register struct ifqueue *ifq; 467 int s; 468 469 /* 470 * `Cannot happen' (see slioctl). Someday we will extend 471 * the line protocol to support other address families. 472 */ 473 if (dst->sa_family != AF_INET) { 474 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit, 475 dst->sa_family); 476 m_freem(m); 477 sc->sc_if.if_noproto++; 478 return (EAFNOSUPPORT); 479 } 480 481 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 482 m_freem(m); 483 return (ENETDOWN); 484 } 485 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 486 m_freem(m); 487 return (EHOSTUNREACH); 488 } 489 ifq = &sc->sc_if.if_snd; 490 ip = mtod(m, struct ip *); 491 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 492 m_freem(m); 493 return (ENETRESET); /* XXX ? */ 494 } 495 if (ip->ip_tos & IPTOS_LOWDELAY) 496 ifq = &sc->sc_fastq; 497 s = splimp(); 498 if (IF_QFULL(ifq)) { 499 IF_DROP(ifq); 500 m_freem(m); 501 splx(s); 502 sc->sc_if.if_oerrors++; 503 return (ENOBUFS); 504 } 505 IF_ENQUEUE(ifq, m); 506 if (sc->sc_ttyp->t_outq.c_cc == 0) 507 slstart(sc->sc_ttyp); 508 splx(s); 509 return (0); 510 } 511 512 /* 513 * Start output on interface. Get another datagram 514 * to send from the interface queue and map it to 515 * the interface before starting output. 516 */ 517 static int 518 slstart(tp) 519 register struct tty *tp; 520 { 521 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 522 register struct mbuf *m; 523 register u_char *cp; 524 register struct ip *ip; 525 int s; 526 struct mbuf *m2; 527 #if NBPFILTER > 0 528 u_char bpfbuf[SLTMAX + SLIP_HDRLEN]; 529 register int len = 0; 530 #endif 531 532 for (;;) { 533 /* 534 * Call output process whether or not there is more in the 535 * output queue. We are being called in lieu of ttstart 536 * and must do what it would. 537 */ 538 (*tp->t_oproc)(tp); 539 540 if (tp->t_outq.c_cc != 0) { 541 if (sc != NULL) 542 sc->sc_flags &= ~SC_OUTWAIT; 543 if (tp->t_outq.c_cc > SLIP_HIWAT) 544 return 0; 545 } 546 547 /* 548 * This happens briefly when the line shuts down. 549 */ 550 if (sc == NULL) 551 return 0; 552 553 /* 554 * Get a packet and send it to the interface. 555 */ 556 s = splimp(); 557 IF_DEQUEUE(&sc->sc_fastq, m); 558 if (m) 559 sc->sc_if.if_omcasts++; /* XXX */ 560 else 561 IF_DEQUEUE(&sc->sc_if.if_snd, m); 562 splx(s); 563 if (m == NULL) 564 return 0; 565 566 /* 567 * We do the header compression here rather than in sloutput 568 * because the packets will be out of order if we are using TOS 569 * queueing, and the connection id compression will get 570 * munged when this happens. 571 */ 572 #if NBPFILTER > 0 573 if (sc->sc_if.if_bpf) { 574 /* 575 * We need to save the TCP/IP header before it's 576 * compressed. To avoid complicated code, we just 577 * copy the entire packet into a stack buffer (since 578 * this is a serial line, packets should be short 579 * and/or the copy should be negligible cost compared 580 * to the packet transmission time). 581 */ 582 register struct mbuf *m1 = m; 583 register u_char *cp = bpfbuf + SLIP_HDRLEN; 584 585 len = 0; 586 do { 587 register int mlen = m1->m_len; 588 589 bcopy(mtod(m1, caddr_t), cp, mlen); 590 cp += mlen; 591 len += mlen; 592 } while (m1 = m1->m_next); 593 } 594 #endif 595 ip = mtod(m, struct ip *); 596 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 597 if (sc->sc_if.if_flags & SC_COMPRESS) 598 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 599 &sc->sc_comp, 1); 600 } 601 #if NBPFILTER > 0 602 if (sc->sc_if.if_bpf) { 603 /* 604 * Put the SLIP pseudo-"link header" in place. The 605 * compressed header is now at the beginning of the 606 * mbuf. 607 */ 608 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 609 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 610 bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN); 611 } 612 #endif 613 614 /* 615 * If system is getting low on clists, just flush our 616 * output queue (if the stuff was important, it'll get 617 * retransmitted). Note that SLTMAX is used instead of 618 * the current if_mtu setting because connections that 619 * have already been established still use the original 620 * (possibly larger) mss. 621 */ 622 if (cfreecount < CLISTRESERVE + SLTMAX) { 623 m_freem(m); 624 sc->sc_if.if_collisions++; 625 continue; 626 } 627 628 sc->sc_flags &= ~SC_OUTWAIT; 629 /* 630 * The extra FRAME_END will start up a new packet, and thus 631 * will flush any accumulated garbage. We do this whenever 632 * the line may have been idle for some time. 633 */ 634 if (tp->t_outq.c_cc == 0) { 635 ++sc->sc_if.if_obytes; 636 (void) putc(FRAME_END, &tp->t_outq); 637 } 638 639 while (m) { 640 register u_char *ep; 641 642 cp = mtod(m, u_char *); ep = cp + m->m_len; 643 while (cp < ep) { 644 /* 645 * Find out how many bytes in the string we can 646 * handle without doing something special. 647 */ 648 register u_char *bp = cp; 649 650 while (cp < ep) { 651 switch (*cp++) { 652 case FRAME_ESCAPE: 653 case FRAME_END: 654 --cp; 655 goto out; 656 } 657 } 658 out: 659 if (cp > bp) { 660 /* 661 * Put n characters at once 662 * into the tty output queue. 663 */ 664 if (b_to_q((char *)bp, cp - bp, 665 &tp->t_outq)) 666 break; 667 sc->sc_if.if_obytes += cp - bp; 668 } 669 /* 670 * If there are characters left in the mbuf, 671 * the first one must be special.. 672 * Put it out in a different form. 673 */ 674 if (cp < ep) { 675 if (putc(FRAME_ESCAPE, &tp->t_outq)) 676 break; 677 if (putc(*cp++ == FRAME_ESCAPE ? 678 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 679 &tp->t_outq)) { 680 (void) unputc(&tp->t_outq); 681 break; 682 } 683 sc->sc_if.if_obytes += 2; 684 } 685 } 686 MFREE(m, m2); 687 m = m2; 688 } 689 690 if (putc(FRAME_END, &tp->t_outq)) { 691 /* 692 * Not enough room. Remove a char to make room 693 * and end the packet normally. 694 * If you get many collisions (more than one or two 695 * a day) you probably do not have enough clists 696 * and you should increase "nclist" in param.c. 697 */ 698 (void) unputc(&tp->t_outq); 699 (void) putc(FRAME_END, &tp->t_outq); 700 sc->sc_if.if_collisions++; 701 } else { 702 ++sc->sc_if.if_obytes; 703 sc->sc_if.if_opackets++; 704 } 705 } 706 return 0; 707 } 708 709 /* 710 * Copy data buffer to mbuf chain; add ifnet pointer. 711 */ 712 static struct mbuf * 713 sl_btom(sc, len) 714 register struct sl_softc *sc; 715 register int len; 716 { 717 register struct mbuf *m; 718 719 MGETHDR(m, M_DONTWAIT, MT_DATA); 720 if (m == NULL) 721 return (NULL); 722 723 /* 724 * If we have more than MHLEN bytes, it's cheaper to 725 * queue the cluster we just filled & allocate a new one 726 * for the input buffer. Otherwise, fill the mbuf we 727 * allocated above. Note that code in the input routine 728 * guarantees that packet will fit in a cluster. 729 */ 730 if (len >= MHLEN) { 731 MCLGET(m, M_DONTWAIT); 732 if ((m->m_flags & M_EXT) == 0) { 733 /* 734 * we couldn't get a cluster - if memory's this 735 * low, it's time to start dropping packets. 736 */ 737 (void) m_free(m); 738 return (NULL); 739 } 740 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 741 m->m_data = (caddr_t)sc->sc_buf; 742 m->m_ext.ext_buf = (caddr_t)((int)sc->sc_buf &~ MCLOFSET); 743 } else 744 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 745 746 m->m_len = len; 747 m->m_pkthdr.len = len; 748 m->m_pkthdr.rcvif = &sc->sc_if; 749 return (m); 750 } 751 752 /* 753 * tty interface receiver interrupt. 754 */ 755 static int 756 slinput(c, tp) 757 register int c; 758 register struct tty *tp; 759 { 760 register struct sl_softc *sc; 761 register struct mbuf *m; 762 register int len; 763 int s; 764 #if NBPFILTER > 0 765 u_char chdr[CHDR_LEN]; 766 #endif 767 768 tk_nin++; 769 sc = (struct sl_softc *)tp->t_sc; 770 if (sc == NULL) 771 return 0; 772 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 773 sc->sc_flags |= SC_ERROR; 774 return 0; 775 } 776 c &= TTY_CHARMASK; 777 778 ++sc->sc_if.if_ibytes; 779 780 if (sc->sc_if.if_flags & IFF_DEBUG) { 781 if (c == ABT_ESC) { 782 /* 783 * If we have a previous abort, see whether 784 * this one is within the time limit. 785 */ 786 if (sc->sc_abortcount && 787 time.tv_sec >= sc->sc_starttime + ABT_WINDOW) 788 sc->sc_abortcount = 0; 789 /* 790 * If we see an abort after "idle" time, count it; 791 * record when the first abort escape arrived. 792 */ 793 if (time.tv_sec >= sc->sc_lasttime + ABT_IDLE) { 794 if (++sc->sc_abortcount == 1) 795 sc->sc_starttime = time.tv_sec; 796 if (sc->sc_abortcount >= ABT_COUNT) { 797 slclose(tp,0); 798 return 0; 799 } 800 } 801 } else 802 sc->sc_abortcount = 0; 803 sc->sc_lasttime = time.tv_sec; 804 } 805 806 switch (c) { 807 808 case TRANS_FRAME_ESCAPE: 809 if (sc->sc_escape) 810 c = FRAME_ESCAPE; 811 break; 812 813 case TRANS_FRAME_END: 814 if (sc->sc_escape) 815 c = FRAME_END; 816 break; 817 818 case FRAME_ESCAPE: 819 sc->sc_escape = 1; 820 return 0; 821 822 case FRAME_END: 823 sc->sc_flags &= ~SC_KEEPALIVE; 824 if(sc->sc_flags & SC_ERROR) { 825 sc->sc_flags &= ~SC_ERROR; 826 goto newpack; 827 } 828 len = sc->sc_mp - sc->sc_buf; 829 if (len < 3) 830 /* less than min length packet - ignore */ 831 goto newpack; 832 833 #if NBPFILTER > 0 834 if (sc->sc_if.if_bpf) { 835 /* 836 * Save the compressed header, so we 837 * can tack it on later. Note that we 838 * will end up copying garbage in some 839 * cases but this is okay. We remember 840 * where the buffer started so we can 841 * compute the new header length. 842 */ 843 bcopy(sc->sc_buf, chdr, CHDR_LEN); 844 } 845 #endif 846 847 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 848 if (c & 0x80) 849 c = TYPE_COMPRESSED_TCP; 850 else if (c == TYPE_UNCOMPRESSED_TCP) 851 *sc->sc_buf &= 0x4f; /* XXX */ 852 /* 853 * We've got something that's not an IP packet. 854 * If compression is enabled, try to decompress it. 855 * Otherwise, if `auto-enable' compression is on and 856 * it's a reasonable packet, decompress it and then 857 * enable compression. Otherwise, drop it. 858 */ 859 if (sc->sc_if.if_flags & SC_COMPRESS) { 860 len = sl_uncompress_tcp(&sc->sc_buf, len, 861 (u_int)c, &sc->sc_comp); 862 if (len <= 0) 863 goto error; 864 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 865 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 866 len = sl_uncompress_tcp(&sc->sc_buf, len, 867 (u_int)c, &sc->sc_comp); 868 if (len <= 0) 869 goto error; 870 sc->sc_if.if_flags |= SC_COMPRESS; 871 } else 872 goto error; 873 } 874 #if NBPFILTER > 0 875 if (sc->sc_if.if_bpf) { 876 /* 877 * Put the SLIP pseudo-"link header" in place. 878 * We couldn't do this any earlier since 879 * decompression probably moved the buffer 880 * pointer. Then, invoke BPF. 881 */ 882 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 883 884 hp[SLX_DIR] = SLIPDIR_IN; 885 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 886 bpf_tap(&sc->sc_if, hp, len + SLIP_HDRLEN); 887 } 888 #endif 889 m = sl_btom(sc, len); 890 if (m == NULL) 891 goto error; 892 893 sc->sc_if.if_ipackets++; 894 895 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 896 m_freem(m); 897 goto newpack; 898 } 899 900 s = splimp(); 901 if (IF_QFULL(&ipintrq)) { 902 IF_DROP(&ipintrq); 903 sc->sc_if.if_ierrors++; 904 sc->sc_if.if_iqdrops++; 905 m_freem(m); 906 } else { 907 IF_ENQUEUE(&ipintrq, m); 908 schednetisr(NETISR_IP); 909 } 910 splx(s); 911 goto newpack; 912 } 913 if (sc->sc_mp < sc->sc_ep) { 914 *sc->sc_mp++ = c; 915 sc->sc_escape = 0; 916 return 0; 917 } 918 919 /* can't put lower; would miss an extra frame */ 920 sc->sc_flags |= SC_ERROR; 921 922 error: 923 sc->sc_if.if_ierrors++; 924 newpack: 925 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 926 sc->sc_escape = 0; 927 return 0; 928 } 929 930 /* 931 * Process an ioctl request. 932 */ 933 static int 934 slioctl(ifp, cmd, data) 935 register struct ifnet *ifp; 936 int cmd; 937 caddr_t data; 938 { 939 register struct ifaddr *ifa = (struct ifaddr *)data; 940 register struct ifreq *ifr = (struct ifreq *)data; 941 register int s, error = 0; 942 943 s = splimp(); 944 945 switch (cmd) { 946 947 case SIOCSIFFLAGS: 948 /* 949 * if.c will set the interface up even if we 950 * don't want it to. 951 */ 952 if (sl_softc[ifp->if_unit].sc_ttyp == NULL) { 953 ifp->if_flags &= ~IFF_UP; 954 } 955 break; 956 case SIOCSIFADDR: 957 /* 958 * This is "historical" - set the interface up when 959 * setting the address. 960 */ 961 if (ifa->ifa_addr->sa_family == AF_INET) { 962 if (sl_softc[ifp->if_unit].sc_ttyp != NULL) 963 if_up(ifp); 964 } else { 965 error = EAFNOSUPPORT; 966 } 967 break; 968 969 case SIOCSIFDSTADDR: 970 if (ifa->ifa_addr->sa_family != AF_INET) 971 error = EAFNOSUPPORT; 972 break; 973 974 case SIOCADDMULTI: 975 case SIOCDELMULTI: 976 if (ifr == 0) { 977 error = EAFNOSUPPORT; /* XXX */ 978 break; 979 } 980 switch (ifr->ifr_addr.sa_family) { 981 982 #ifdef INET 983 case AF_INET: 984 break; 985 #endif 986 987 default: 988 error = EAFNOSUPPORT; 989 break; 990 } 991 break; 992 993 case SIOCSIFMTU: 994 /* 995 * Set the interface MTU. 996 */ 997 if (ifr->ifr_mtu > SLTMAX) 998 error = EINVAL; 999 else { 1000 struct tty *tp; 1001 1002 ifp->if_mtu = ifr->ifr_mtu; 1003 tp = sl_softc[ifp->if_unit].sc_ttyp; 1004 if (tp != NULL) 1005 clist_alloc_cblocks(&tp->t_outq, 1006 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1007 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1008 } 1009 break; 1010 1011 default: 1012 error = EINVAL; 1013 } 1014 splx(s); 1015 return (error); 1016 } 1017 1018 static void 1019 sl_keepalive(chan) 1020 void *chan; 1021 { 1022 struct sl_softc *sc = chan; 1023 1024 if (sc->sc_keepalive) { 1025 if (sc->sc_flags & SC_KEEPALIVE) 1026 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1027 else 1028 sc->sc_flags |= SC_KEEPALIVE; 1029 timeout(sl_keepalive, sc, sc->sc_keepalive); 1030 } else { 1031 sc->sc_flags &= ~SC_KEEPALIVE; 1032 untimeout(sl_keepalive, sc); 1033 } 1034 } 1035 1036 static void 1037 sl_outfill(chan) 1038 void *chan; 1039 { 1040 struct sl_softc *sc = chan; 1041 register struct tty *tp = sc->sc_ttyp; 1042 int s; 1043 1044 if (sc->sc_outfill && tp != NULL) { 1045 if (sc->sc_flags & SC_OUTWAIT) { 1046 s = splimp (); 1047 ++sc->sc_if.if_obytes; 1048 (void) putc(FRAME_END, &tp->t_outq); 1049 (*tp->t_oproc)(tp); 1050 splx (s); 1051 } else 1052 sc->sc_flags |= SC_OUTWAIT; 1053 timeout(sl_outfill, sc, sc->sc_outfill); 1054 } else { 1055 sc->sc_flags &= ~SC_OUTWAIT; 1056 untimeout(sl_outfill, sc); 1057 } 1058 } 1059 1060 #endif
Cache object: 57752a19b1a6e143113b7b10c94aaaca
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