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 * $FreeBSD$ 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 #include "opt_inet.h" 73 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/proc.h> 77 #include <sys/malloc.h> 78 #include <sys/mbuf.h> 79 #include <sys/dkstat.h> 80 #include <sys/socket.h> 81 #include <sys/sockio.h> 82 #include <sys/fcntl.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 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 99 #error "Huh? Slip without inet?" 100 #endif 101 102 #include <net/slcompress.h> 103 #include <net/if_slvar.h> 104 #include <net/slip.h> 105 106 #if NBPFILTER > 0 107 #include <net/bpf.h> 108 #endif 109 110 static void slattach __P((void *)); 111 PSEUDO_SET(slattach, if_sl); 112 113 /* 114 * SLRMAX is a hard limit on input packet size. To simplify the code 115 * and improve performance, we require that packets fit in an mbuf 116 * cluster, and if we get a compressed packet, there's enough extra 117 * room to expand the header into a max length tcp/ip header (128 118 * bytes). So, SLRMAX can be at most 119 * MCLBYTES - 128 120 * 121 * SLMTU is the default transmit MTU. The transmit MTU should be kept 122 * small enough so that interactive use doesn't suffer, but large 123 * enough to provide good performance. 552 is a good choice for SLMTU 124 * because it is high enough to not fragment TCP packets being routed 125 * through this host. Packet fragmentation is bad with SLIP because 126 * fragment headers aren't compressed. The previous assumptions about 127 * the best MTU value don't really hold when using modern modems with 128 * BTLZ data compression because the modem buffers play a much larger 129 * role in interactive performance than the MTU. The MTU can be changed 130 * at any time to suit the specific environment with ifconfig(8), and 131 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 132 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 133 * handles this better). 134 * 135 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 136 * of us (i.e., in clists waiting to be picked up by the tty output 137 * interrupt). If we queue a lot of data downstream, it's immune to 138 * our t.o.s. queuing. 139 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 140 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 141 * wait is dependent on the ftp window size but that's typically 142 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 143 * the cost (in idle time on the wire) of the tty driver running 144 * off the end of its clists & having to call back slstart for a 145 * new packet. For a tty interface with any buffering at all, this 146 * cost will be zero. Even with a totally brain dead interface (like 147 * the one on a typical workstation), the cost will be <= 1 character 148 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 149 * at most 1% while maintaining good interactive response. 150 */ 151 #if NBPFILTER > 0 152 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 153 #else 154 #define BUFOFFSET (128+sizeof(struct ifnet **)) 155 #endif 156 #define SLRMAX (MCLBYTES - BUFOFFSET) 157 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 158 #ifndef SLMTU 159 #define SLMTU 552 /* default MTU */ 160 #endif 161 #define SLTMAX 1500 /* maximum MTU */ 162 #define SLIP_HIWAT roundup(50,CBSIZE) 163 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 164 165 /* 166 * SLIP ABORT ESCAPE MECHANISM: 167 * (inspired by HAYES modem escape arrangement) 168 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 169 * within window time signals a "soft" exit from slip mode by remote end 170 * if the IFF_DEBUG flag is on. 171 */ 172 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 173 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 174 #define ABT_COUNT 3 /* count of escapes for abort */ 175 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 176 177 static struct sl_softc sl_softc[NSL]; 178 179 #define FRAME_END 0xc0 /* Frame End */ 180 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 181 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 182 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 183 184 static int slinit __P((struct sl_softc *)); 185 static struct mbuf *sl_btom __P((struct sl_softc *, int)); 186 static timeout_t sl_keepalive; 187 static timeout_t sl_outfill; 188 static int slclose __P((struct tty *,int)); 189 static int slinput __P((int, struct tty *)); 190 static int slioctl __P((struct ifnet *, u_long, caddr_t)); 191 static int sltioctl __P((struct tty *, u_long, caddr_t, int, struct proc *)); 192 static int slopen __P((dev_t, struct tty *)); 193 static int sloutput __P((struct ifnet *, 194 struct mbuf *, struct sockaddr *, struct rtentry *)); 195 static int slstart __P((struct tty *)); 196 197 static struct linesw slipdisc = { 198 slopen, slclose, l_noread, l_nowrite, 199 sltioctl, slinput, slstart, ttymodem, 200 FRAME_END 201 }; 202 203 /* 204 * Called from boot code to establish sl interfaces. 205 */ 206 static void 207 slattach(dummy) 208 void *dummy; 209 { 210 register struct sl_softc *sc; 211 register int i = 0; 212 213 linesw[SLIPDISC] = slipdisc; 214 215 for (sc = sl_softc; i < NSL; sc++) { 216 sc->sc_if.if_name = "sl"; 217 sc->sc_if.if_unit = i++; 218 sc->sc_if.if_mtu = SLMTU; 219 sc->sc_if.if_flags = 220 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 221 sc->sc_if.if_type = IFT_SLIP; 222 sc->sc_if.if_ioctl = slioctl; 223 sc->sc_if.if_output = sloutput; 224 sc->sc_if.if_snd.ifq_maxlen = 50; 225 sc->sc_fastq.ifq_maxlen = 32; 226 sc->sc_if.if_linkmib = sc; 227 sc->sc_if.if_linkmiblen = sizeof *sc; 228 if_attach(&sc->sc_if); 229 #if NBPFILTER > 0 230 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 231 #endif 232 } 233 } 234 235 static int 236 slinit(sc) 237 register struct sl_softc *sc; 238 { 239 register caddr_t p; 240 241 if (sc->sc_ep == (u_char *) 0) { 242 MCLALLOC(p, M_WAIT); 243 if (p) 244 sc->sc_ep = (u_char *)p + SLBUFSIZE; 245 else { 246 printf("sl%d: can't allocate buffer\n", sc - sl_softc); 247 return (0); 248 } 249 } 250 sc->sc_buf = sc->sc_ep - SLRMAX; 251 sc->sc_mp = sc->sc_buf; 252 sl_compress_init(&sc->sc_comp, -1); 253 return (1); 254 } 255 256 /* 257 * Line specific open routine. 258 * Attach the given tty to the first available sl unit. 259 */ 260 /* ARGSUSED */ 261 static int 262 slopen(dev, tp) 263 dev_t dev; 264 register struct tty *tp; 265 { 266 struct proc *p = curproc; /* XXX */ 267 register struct sl_softc *sc; 268 register int nsl; 269 int s, error; 270 271 error = suser(p->p_ucred, &p->p_acflag); 272 if (error) 273 return (error); 274 275 if (tp->t_line == SLIPDISC) 276 return (0); 277 278 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 279 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) { 280 if (slinit(sc) == 0) 281 return (ENOBUFS); 282 tp->t_sc = (caddr_t)sc; 283 sc->sc_ttyp = tp; 284 sc->sc_if.if_baudrate = tp->t_ospeed; 285 ttyflush(tp, FREAD | FWRITE); 286 287 tp->t_line = SLIPDISC; 288 /* 289 * We don't use t_canq or t_rawq, so reduce their 290 * cblock resources to 0. Reserve enough cblocks 291 * for t_outq to guarantee that we can fit a full 292 * packet if the SLIP_HIWAT check allows slstart() 293 * to loop. Use the same value for the cblock 294 * limit since the reserved blocks should always 295 * be enough. Reserving cblocks probably makes 296 * the CLISTRESERVE check unnecessary and wasteful. 297 */ 298 clist_alloc_cblocks(&tp->t_canq, 0, 0); 299 clist_alloc_cblocks(&tp->t_outq, 300 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 301 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 302 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 303 304 s = splnet(); 305 if_up(&sc->sc_if); 306 splx(s); 307 return (0); 308 } 309 return (ENXIO); 310 } 311 312 /* 313 * Line specific close routine. 314 * Detach the tty from the sl unit. 315 */ 316 static int 317 slclose(tp,flag) 318 struct tty *tp; 319 int flag; 320 { 321 register struct sl_softc *sc; 322 int s; 323 324 ttyflush(tp, FREAD | FWRITE); 325 /* 326 * XXX the placement of the following spl is misleading. tty 327 * interrupts must be blocked across line discipline switches 328 * and throughout closes to avoid races. 329 */ 330 s = splimp(); /* actually, max(spltty, splnet) */ 331 clist_free_cblocks(&tp->t_outq); 332 tp->t_line = 0; 333 sc = (struct sl_softc *)tp->t_sc; 334 if (sc != NULL) { 335 if (sc->sc_outfill) { 336 sc->sc_outfill = 0; 337 untimeout(sl_outfill, sc, sc->sc_ofhandle); 338 } 339 if (sc->sc_keepalive) { 340 sc->sc_keepalive = 0; 341 untimeout(sl_keepalive, sc, sc->sc_kahandle); 342 } 343 if_down(&sc->sc_if); 344 sc->sc_flags &= SC_STATIC; 345 sc->sc_ttyp = NULL; 346 tp->t_sc = NULL; 347 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE)); 348 sc->sc_ep = 0; 349 sc->sc_mp = 0; 350 sc->sc_buf = 0; 351 } 352 splx(s); 353 return 0; 354 } 355 356 /* 357 * Line specific (tty) ioctl routine. 358 * Provide a way to get the sl unit number. 359 */ 360 /* ARGSUSED */ 361 static int 362 sltioctl(tp, cmd, data, flag, p) 363 struct tty *tp; 364 u_long cmd; 365 caddr_t data; 366 int flag; 367 struct proc *p; 368 { 369 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc; 370 int s, nsl; 371 372 s = splimp(); 373 switch (cmd) { 374 case SLIOCGUNIT: 375 *(int *)data = sc->sc_if.if_unit; 376 break; 377 378 case SLIOCSUNIT: 379 if (sc->sc_if.if_unit != *(u_int *)data) { 380 for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) { 381 if ( nc->sc_if.if_unit == *(u_int *)data 382 && nc->sc_ttyp == NULL 383 ) { 384 tmpnc = malloc(sizeof *tmpnc, M_TEMP, 385 M_NOWAIT); 386 if (tmpnc == NULL) { 387 splx(s); 388 return (ENOMEM); 389 } 390 *tmpnc = *nc; 391 *nc = *sc; 392 nc->sc_if = tmpnc->sc_if; 393 tmpnc->sc_if = sc->sc_if; 394 *sc = *tmpnc; 395 free(tmpnc, M_TEMP); 396 if (sc->sc_if.if_flags & IFF_UP) { 397 if_down(&sc->sc_if); 398 if (!(nc->sc_if.if_flags & IFF_UP)) 399 if_up(&nc->sc_if); 400 } else if (nc->sc_if.if_flags & IFF_UP) 401 if_down(&nc->sc_if); 402 sc->sc_flags &= ~SC_STATIC; 403 sc->sc_flags |= (nc->sc_flags & SC_STATIC); 404 tp->t_sc = sc = nc; 405 clist_alloc_cblocks(&tp->t_outq, 406 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 407 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 408 sl_compress_init(&sc->sc_comp, -1); 409 goto slfound; 410 } 411 } 412 splx(s); 413 return (ENXIO); 414 } 415 slfound: 416 sc->sc_flags |= SC_STATIC; 417 break; 418 419 case SLIOCSKEEPAL: 420 sc->sc_keepalive = *(u_int *)data * hz; 421 if (sc->sc_keepalive) { 422 sc->sc_flags |= SC_KEEPALIVE; 423 sc->sc_kahandle = timeout(sl_keepalive, sc, 424 sc->sc_keepalive); 425 } else { 426 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 427 untimeout(sl_keepalive, sc, sc->sc_kahandle); 428 sc->sc_flags &= ~SC_KEEPALIVE; 429 } 430 } 431 break; 432 433 case SLIOCGKEEPAL: 434 *(int *)data = sc->sc_keepalive / hz; 435 break; 436 437 case SLIOCSOUTFILL: 438 sc->sc_outfill = *(u_int *)data * hz; 439 if (sc->sc_outfill) { 440 sc->sc_flags |= SC_OUTWAIT; 441 sc->sc_ofhandle = timeout(sl_outfill, sc, 442 sc->sc_outfill); 443 } else { 444 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 445 untimeout(sl_outfill, sc, sc->sc_ofhandle); 446 sc->sc_flags &= ~SC_OUTWAIT; 447 } 448 } 449 break; 450 451 case SLIOCGOUTFILL: 452 *(int *)data = sc->sc_outfill / hz; 453 break; 454 455 default: 456 splx(s); 457 return (ENOIOCTL); 458 } 459 splx(s); 460 return (0); 461 } 462 463 /* 464 * Queue a packet. Start transmission if not active. 465 * Compression happens in slstart; if we do it here, IP TOS 466 * will cause us to not compress "background" packets, because 467 * ordering gets trashed. It can be done for all packets in slstart. 468 */ 469 static int 470 sloutput(ifp, m, dst, rtp) 471 struct ifnet *ifp; 472 register struct mbuf *m; 473 struct sockaddr *dst; 474 struct rtentry *rtp; 475 { 476 register struct sl_softc *sc = &sl_softc[ifp->if_unit]; 477 register struct ip *ip; 478 register struct ifqueue *ifq; 479 int s; 480 481 /* 482 * `Cannot happen' (see slioctl). Someday we will extend 483 * the line protocol to support other address families. 484 */ 485 if (dst->sa_family != AF_INET) { 486 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit, 487 dst->sa_family); 488 m_freem(m); 489 sc->sc_if.if_noproto++; 490 return (EAFNOSUPPORT); 491 } 492 493 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 494 m_freem(m); 495 return (ENETDOWN); 496 } 497 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 498 m_freem(m); 499 return (EHOSTUNREACH); 500 } 501 ifq = &sc->sc_if.if_snd; 502 ip = mtod(m, struct ip *); 503 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 504 m_freem(m); 505 return (ENETRESET); /* XXX ? */ 506 } 507 if (ip->ip_tos & IPTOS_LOWDELAY) 508 ifq = &sc->sc_fastq; 509 s = splimp(); 510 if (IF_QFULL(ifq)) { 511 IF_DROP(ifq); 512 m_freem(m); 513 splx(s); 514 sc->sc_if.if_oerrors++; 515 return (ENOBUFS); 516 } 517 IF_ENQUEUE(ifq, m); 518 if (sc->sc_ttyp->t_outq.c_cc == 0) 519 slstart(sc->sc_ttyp); 520 splx(s); 521 return (0); 522 } 523 524 /* 525 * Start output on interface. Get another datagram 526 * to send from the interface queue and map it to 527 * the interface before starting output. 528 */ 529 static int 530 slstart(tp) 531 register struct tty *tp; 532 { 533 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 534 register struct mbuf *m; 535 register u_char *cp; 536 register struct ip *ip; 537 int s; 538 struct mbuf *m2; 539 #if NBPFILTER > 0 540 u_char bpfbuf[SLTMAX + SLIP_HDRLEN]; 541 register int len = 0; 542 #endif 543 544 for (;;) { 545 /* 546 * Call output process whether or not there is more in the 547 * output queue. We are being called in lieu of ttstart 548 * and must do what it would. 549 */ 550 (*tp->t_oproc)(tp); 551 552 if (tp->t_outq.c_cc != 0) { 553 if (sc != NULL) 554 sc->sc_flags &= ~SC_OUTWAIT; 555 if (tp->t_outq.c_cc > SLIP_HIWAT) 556 return 0; 557 } 558 559 /* 560 * This happens briefly when the line shuts down. 561 */ 562 if (sc == NULL) 563 return 0; 564 565 /* 566 * Get a packet and send it to the interface. 567 */ 568 s = splimp(); 569 IF_DEQUEUE(&sc->sc_fastq, m); 570 if (m) 571 sc->sc_if.if_omcasts++; /* XXX */ 572 else 573 IF_DEQUEUE(&sc->sc_if.if_snd, m); 574 splx(s); 575 if (m == NULL) 576 return 0; 577 578 /* 579 * We do the header compression here rather than in sloutput 580 * because the packets will be out of order if we are using TOS 581 * queueing, and the connection id compression will get 582 * munged when this happens. 583 */ 584 #if NBPFILTER > 0 585 if (sc->sc_if.if_bpf) { 586 /* 587 * We need to save the TCP/IP header before it's 588 * compressed. To avoid complicated code, we just 589 * copy the entire packet into a stack buffer (since 590 * this is a serial line, packets should be short 591 * and/or the copy should be negligible cost compared 592 * to the packet transmission time). 593 */ 594 register struct mbuf *m1 = m; 595 register u_char *cp = bpfbuf + SLIP_HDRLEN; 596 597 len = 0; 598 do { 599 register int mlen = m1->m_len; 600 601 bcopy(mtod(m1, caddr_t), cp, mlen); 602 cp += mlen; 603 len += mlen; 604 } while (m1 = m1->m_next); 605 } 606 #endif 607 ip = mtod(m, struct ip *); 608 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 609 if (sc->sc_if.if_flags & SC_COMPRESS) 610 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 611 &sc->sc_comp, 1); 612 } 613 #if NBPFILTER > 0 614 if (sc->sc_if.if_bpf) { 615 /* 616 * Put the SLIP pseudo-"link header" in place. The 617 * compressed header is now at the beginning of the 618 * mbuf. 619 */ 620 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 621 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 622 bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN); 623 } 624 #endif 625 626 /* 627 * If system is getting low on clists, just flush our 628 * output queue (if the stuff was important, it'll get 629 * retransmitted). Note that SLTMAX is used instead of 630 * the current if_mtu setting because connections that 631 * have already been established still use the original 632 * (possibly larger) mss. 633 */ 634 if (cfreecount < CLISTRESERVE + SLTMAX) { 635 m_freem(m); 636 sc->sc_if.if_collisions++; 637 continue; 638 } 639 640 sc->sc_flags &= ~SC_OUTWAIT; 641 /* 642 * The extra FRAME_END will start up a new packet, and thus 643 * will flush any accumulated garbage. We do this whenever 644 * the line may have been idle for some time. 645 */ 646 if (tp->t_outq.c_cc == 0) { 647 ++sc->sc_if.if_obytes; 648 (void) putc(FRAME_END, &tp->t_outq); 649 } 650 651 while (m) { 652 register u_char *ep; 653 654 cp = mtod(m, u_char *); ep = cp + m->m_len; 655 while (cp < ep) { 656 /* 657 * Find out how many bytes in the string we can 658 * handle without doing something special. 659 */ 660 register u_char *bp = cp; 661 662 while (cp < ep) { 663 switch (*cp++) { 664 case FRAME_ESCAPE: 665 case FRAME_END: 666 --cp; 667 goto out; 668 } 669 } 670 out: 671 if (cp > bp) { 672 /* 673 * Put n characters at once 674 * into the tty output queue. 675 */ 676 if (b_to_q((char *)bp, cp - bp, 677 &tp->t_outq)) 678 break; 679 sc->sc_if.if_obytes += cp - bp; 680 } 681 /* 682 * If there are characters left in the mbuf, 683 * the first one must be special.. 684 * Put it out in a different form. 685 */ 686 if (cp < ep) { 687 if (putc(FRAME_ESCAPE, &tp->t_outq)) 688 break; 689 if (putc(*cp++ == FRAME_ESCAPE ? 690 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 691 &tp->t_outq)) { 692 (void) unputc(&tp->t_outq); 693 break; 694 } 695 sc->sc_if.if_obytes += 2; 696 } 697 } 698 MFREE(m, m2); 699 m = m2; 700 } 701 702 if (putc(FRAME_END, &tp->t_outq)) { 703 /* 704 * Not enough room. Remove a char to make room 705 * and end the packet normally. 706 * If you get many collisions (more than one or two 707 * a day) you probably do not have enough clists 708 * and you should increase "nclist" in param.c. 709 */ 710 (void) unputc(&tp->t_outq); 711 (void) putc(FRAME_END, &tp->t_outq); 712 sc->sc_if.if_collisions++; 713 } else { 714 ++sc->sc_if.if_obytes; 715 sc->sc_if.if_opackets++; 716 } 717 } 718 return 0; 719 } 720 721 /* 722 * Copy data buffer to mbuf chain; add ifnet pointer. 723 */ 724 static struct mbuf * 725 sl_btom(sc, len) 726 register struct sl_softc *sc; 727 register int len; 728 { 729 register struct mbuf *m; 730 731 MGETHDR(m, M_DONTWAIT, MT_DATA); 732 if (m == NULL) 733 return (NULL); 734 735 /* 736 * If we have more than MHLEN bytes, it's cheaper to 737 * queue the cluster we just filled & allocate a new one 738 * for the input buffer. Otherwise, fill the mbuf we 739 * allocated above. Note that code in the input routine 740 * guarantees that packet will fit in a cluster. 741 */ 742 if (len >= MHLEN) { 743 MCLGET(m, M_DONTWAIT); 744 if ((m->m_flags & M_EXT) == 0) { 745 /* 746 * we couldn't get a cluster - if memory's this 747 * low, it's time to start dropping packets. 748 */ 749 (void) m_free(m); 750 return (NULL); 751 } 752 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 753 m->m_data = (caddr_t)sc->sc_buf; 754 m->m_ext.ext_buf = (caddr_t)((intptr_t)sc->sc_buf &~ MCLOFSET); 755 } else 756 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 757 758 m->m_len = len; 759 m->m_pkthdr.len = len; 760 m->m_pkthdr.rcvif = &sc->sc_if; 761 return (m); 762 } 763 764 /* 765 * tty interface receiver interrupt. 766 */ 767 static int 768 slinput(c, tp) 769 register int c; 770 register struct tty *tp; 771 { 772 register struct sl_softc *sc; 773 register struct mbuf *m; 774 register int len; 775 int s; 776 #if NBPFILTER > 0 777 u_char chdr[CHDR_LEN]; 778 #endif 779 780 tk_nin++; 781 sc = (struct sl_softc *)tp->t_sc; 782 if (sc == NULL) 783 return 0; 784 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 785 sc->sc_flags |= SC_ERROR; 786 return 0; 787 } 788 c &= TTY_CHARMASK; 789 790 ++sc->sc_if.if_ibytes; 791 792 if (sc->sc_if.if_flags & IFF_DEBUG) { 793 if (c == ABT_ESC) { 794 /* 795 * If we have a previous abort, see whether 796 * this one is within the time limit. 797 */ 798 if (sc->sc_abortcount && 799 time_second >= sc->sc_starttime + ABT_WINDOW) 800 sc->sc_abortcount = 0; 801 /* 802 * If we see an abort after "idle" time, count it; 803 * record when the first abort escape arrived. 804 */ 805 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 806 if (++sc->sc_abortcount == 1) 807 sc->sc_starttime = time_second; 808 if (sc->sc_abortcount >= ABT_COUNT) { 809 slclose(tp,0); 810 return 0; 811 } 812 } 813 } else 814 sc->sc_abortcount = 0; 815 sc->sc_lasttime = time_second; 816 } 817 818 switch (c) { 819 820 case TRANS_FRAME_ESCAPE: 821 if (sc->sc_escape) 822 c = FRAME_ESCAPE; 823 break; 824 825 case TRANS_FRAME_END: 826 if (sc->sc_escape) 827 c = FRAME_END; 828 break; 829 830 case FRAME_ESCAPE: 831 sc->sc_escape = 1; 832 return 0; 833 834 case FRAME_END: 835 sc->sc_flags &= ~SC_KEEPALIVE; 836 if(sc->sc_flags & SC_ERROR) { 837 sc->sc_flags &= ~SC_ERROR; 838 goto newpack; 839 } 840 len = sc->sc_mp - sc->sc_buf; 841 if (len < 3) 842 /* less than min length packet - ignore */ 843 goto newpack; 844 845 #if NBPFILTER > 0 846 if (sc->sc_if.if_bpf) { 847 /* 848 * Save the compressed header, so we 849 * can tack it on later. Note that we 850 * will end up copying garbage in some 851 * cases but this is okay. We remember 852 * where the buffer started so we can 853 * compute the new header length. 854 */ 855 bcopy(sc->sc_buf, chdr, CHDR_LEN); 856 } 857 #endif 858 859 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 860 if (c & 0x80) 861 c = TYPE_COMPRESSED_TCP; 862 else if (c == TYPE_UNCOMPRESSED_TCP) 863 *sc->sc_buf &= 0x4f; /* XXX */ 864 /* 865 * We've got something that's not an IP packet. 866 * If compression is enabled, try to decompress it. 867 * Otherwise, if `auto-enable' compression is on and 868 * it's a reasonable packet, decompress it and then 869 * enable compression. Otherwise, drop it. 870 */ 871 if (sc->sc_if.if_flags & SC_COMPRESS) { 872 len = sl_uncompress_tcp(&sc->sc_buf, len, 873 (u_int)c, &sc->sc_comp); 874 if (len <= 0) 875 goto error; 876 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 877 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 878 len = sl_uncompress_tcp(&sc->sc_buf, len, 879 (u_int)c, &sc->sc_comp); 880 if (len <= 0) 881 goto error; 882 sc->sc_if.if_flags |= SC_COMPRESS; 883 } else 884 goto error; 885 } 886 #if NBPFILTER > 0 887 if (sc->sc_if.if_bpf) { 888 /* 889 * Put the SLIP pseudo-"link header" in place. 890 * We couldn't do this any earlier since 891 * decompression probably moved the buffer 892 * pointer. Then, invoke BPF. 893 */ 894 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 895 896 hp[SLX_DIR] = SLIPDIR_IN; 897 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 898 bpf_tap(&sc->sc_if, hp, len + SLIP_HDRLEN); 899 } 900 #endif 901 m = sl_btom(sc, len); 902 if (m == NULL) 903 goto error; 904 905 sc->sc_if.if_ipackets++; 906 907 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 908 m_freem(m); 909 goto newpack; 910 } 911 912 s = splimp(); 913 if (IF_QFULL(&ipintrq)) { 914 IF_DROP(&ipintrq); 915 sc->sc_if.if_ierrors++; 916 sc->sc_if.if_iqdrops++; 917 m_freem(m); 918 } else { 919 IF_ENQUEUE(&ipintrq, m); 920 schednetisr(NETISR_IP); 921 } 922 splx(s); 923 goto newpack; 924 } 925 if (sc->sc_mp < sc->sc_ep) { 926 *sc->sc_mp++ = c; 927 sc->sc_escape = 0; 928 return 0; 929 } 930 931 /* can't put lower; would miss an extra frame */ 932 sc->sc_flags |= SC_ERROR; 933 934 error: 935 sc->sc_if.if_ierrors++; 936 newpack: 937 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 938 sc->sc_escape = 0; 939 return 0; 940 } 941 942 /* 943 * Process an ioctl request. 944 */ 945 static int 946 slioctl(ifp, cmd, data) 947 register struct ifnet *ifp; 948 u_long cmd; 949 caddr_t data; 950 { 951 register struct ifaddr *ifa = (struct ifaddr *)data; 952 register struct ifreq *ifr = (struct ifreq *)data; 953 register int s, error = 0; 954 955 s = splimp(); 956 957 switch (cmd) { 958 959 case SIOCSIFFLAGS: 960 /* 961 * if.c will set the interface up even if we 962 * don't want it to. 963 */ 964 if (sl_softc[ifp->if_unit].sc_ttyp == NULL) { 965 ifp->if_flags &= ~IFF_UP; 966 } 967 break; 968 case SIOCSIFADDR: 969 /* 970 * This is "historical" - set the interface up when 971 * setting the address. 972 */ 973 if (ifa->ifa_addr->sa_family == AF_INET) { 974 if (sl_softc[ifp->if_unit].sc_ttyp != NULL) 975 ifp->if_flags |= IFF_UP; 976 } else { 977 error = EAFNOSUPPORT; 978 } 979 break; 980 981 case SIOCSIFDSTADDR: 982 if (ifa->ifa_addr->sa_family != AF_INET) 983 error = EAFNOSUPPORT; 984 break; 985 986 case SIOCADDMULTI: 987 case SIOCDELMULTI: 988 break; 989 990 case SIOCSIFMTU: 991 /* 992 * Set the interface MTU. 993 */ 994 if (ifr->ifr_mtu > SLTMAX) 995 error = EINVAL; 996 else { 997 struct tty *tp; 998 999 ifp->if_mtu = ifr->ifr_mtu; 1000 tp = sl_softc[ifp->if_unit].sc_ttyp; 1001 if (tp != NULL) 1002 clist_alloc_cblocks(&tp->t_outq, 1003 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1004 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1005 } 1006 break; 1007 1008 default: 1009 error = EINVAL; 1010 } 1011 splx(s); 1012 return (error); 1013 } 1014 1015 static void 1016 sl_keepalive(chan) 1017 void *chan; 1018 { 1019 struct sl_softc *sc = chan; 1020 1021 if (sc->sc_keepalive) { 1022 if (sc->sc_flags & SC_KEEPALIVE) 1023 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1024 else 1025 sc->sc_flags |= SC_KEEPALIVE; 1026 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1027 } else { 1028 sc->sc_flags &= ~SC_KEEPALIVE; 1029 } 1030 } 1031 1032 static void 1033 sl_outfill(chan) 1034 void *chan; 1035 { 1036 struct sl_softc *sc = chan; 1037 register struct tty *tp = sc->sc_ttyp; 1038 int s; 1039 1040 if (sc->sc_outfill && tp != NULL) { 1041 if (sc->sc_flags & SC_OUTWAIT) { 1042 s = splimp (); 1043 ++sc->sc_if.if_obytes; 1044 (void) putc(FRAME_END, &tp->t_outq); 1045 (*tp->t_oproc)(tp); 1046 splx (s); 1047 } else 1048 sc->sc_flags |= SC_OUTWAIT; 1049 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1050 } else { 1051 sc->sc_flags &= ~SC_OUTWAIT; 1052 } 1053 } 1054 1055 #endif
Cache object: c878e45df672d26ba4992c76c11de669
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