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 70 #include "opt_inet.h" 71 #if !defined(KLD_MODULE) 72 #include "opt_slip.h" 73 #endif 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 #include <net/bpf.h> 107 108 #ifdef __i386__ 109 #include <i386/isa/intr_machdep.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 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 154 #define SLRMAX (MCLBYTES - BUFOFFSET) 155 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 156 #ifndef SLMTU 157 #define SLMTU 552 /* default MTU */ 158 #endif 159 #define SLTMAX 1500 /* maximum MTU */ 160 #define SLIP_HIWAT roundup(50,CBSIZE) 161 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 162 163 /* 164 * SLIP ABORT ESCAPE MECHANISM: 165 * (inspired by HAYES modem escape arrangement) 166 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 167 * within window time signals a "soft" exit from slip mode by remote end 168 * if the IFF_DEBUG flag is on. 169 */ 170 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 171 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 172 #define ABT_COUNT 3 /* count of escapes for abort */ 173 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 174 175 static struct sl_softc sl_softc[NSL]; 176 177 #define FRAME_END 0xc0 /* Frame End */ 178 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 179 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 180 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 181 182 static int slinit __P((struct sl_softc *)); 183 static struct mbuf *sl_btom __P((struct sl_softc *, int)); 184 static timeout_t sl_keepalive; 185 static timeout_t sl_outfill; 186 static int slclose __P((struct tty *,int)); 187 static int slinput __P((int, struct tty *)); 188 static int slioctl __P((struct ifnet *, u_long, caddr_t)); 189 static int sltioctl __P((struct tty *, u_long, caddr_t, int, struct proc *)); 190 static int slopen __P((dev_t, struct tty *)); 191 static int sloutput __P((struct ifnet *, 192 struct mbuf *, struct sockaddr *, struct rtentry *)); 193 static int slstart __P((struct tty *)); 194 195 static struct linesw slipdisc = { 196 slopen, slclose, l_noread, l_nowrite, 197 sltioctl, slinput, slstart, ttymodem, 198 FRAME_END 199 }; 200 201 /* 202 * Called from boot code to establish sl interfaces. 203 */ 204 static void 205 slattach(dummy) 206 void *dummy; 207 { 208 register struct sl_softc *sc; 209 register int i = 0; 210 211 linesw[SLIPDISC] = slipdisc; 212 213 for (sc = sl_softc; i < NSL; sc++) { 214 sc->sc_if.if_name = "sl"; 215 sc->sc_if.if_unit = i++; 216 sc->sc_if.if_mtu = SLMTU; 217 sc->sc_if.if_flags = 218 #ifdef SLIP_IFF_OPTS 219 SLIP_IFF_OPTS; 220 #else 221 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 222 #endif 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 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 232 } 233 } 234 235 static int 236 slinit(sc) 237 register struct sl_softc *sc; 238 { 239 register caddr_t p; 240 241 #ifdef __i386__ 242 int s; 243 244 s = splhigh(); 245 tty_imask |= net_imask; 246 net_imask = tty_imask; 247 update_intr_masks(); 248 splx(s); 249 if (bootverbose) 250 printf("new imasks: bio %x, tty %x, net %x\n", 251 bio_imask, tty_imask, net_imask); 252 #endif 253 if (sc->sc_ep == (u_char *) 0) { 254 MCLALLOC(p, M_WAIT); 255 if (p) 256 sc->sc_ep = (u_char *)p + SLBUFSIZE; 257 else { 258 printf("sl%ld: can't allocate buffer\n", 259 (long)(sc - sl_softc)); 260 return (0); 261 } 262 } 263 sc->sc_buf = sc->sc_ep - SLRMAX; 264 sc->sc_mp = sc->sc_buf; 265 sl_compress_init(&sc->sc_comp, -1); 266 return (1); 267 } 268 269 /* 270 * Line specific open routine. 271 * Attach the given tty to the first available sl unit. 272 */ 273 /* ARGSUSED */ 274 static int 275 slopen(dev, tp) 276 dev_t dev; 277 register struct tty *tp; 278 { 279 struct proc *p = curproc; /* XXX */ 280 register struct sl_softc *sc; 281 register int nsl; 282 int s, error; 283 284 error = suser(p); 285 if (error) 286 return (error); 287 288 if (tp->t_line == SLIPDISC) 289 return (0); 290 291 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 292 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) { 293 if (slinit(sc) == 0) 294 return (ENOBUFS); 295 tp->t_sc = (caddr_t)sc; 296 sc->sc_ttyp = tp; 297 sc->sc_if.if_baudrate = tp->t_ospeed; 298 ttyflush(tp, FREAD | FWRITE); 299 300 tp->t_line = SLIPDISC; 301 /* 302 * We don't use t_canq or t_rawq, so reduce their 303 * cblock resources to 0. Reserve enough cblocks 304 * for t_outq to guarantee that we can fit a full 305 * packet if the SLIP_HIWAT check allows slstart() 306 * to loop. Use the same value for the cblock 307 * limit since the reserved blocks should always 308 * be enough. Reserving cblocks probably makes 309 * the CLISTRESERVE check unnecessary and wasteful. 310 */ 311 clist_alloc_cblocks(&tp->t_canq, 0, 0); 312 clist_alloc_cblocks(&tp->t_outq, 313 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 314 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 315 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 316 317 s = splnet(); 318 if_up(&sc->sc_if); 319 splx(s); 320 return (0); 321 } 322 return (ENXIO); 323 } 324 325 /* 326 * Line specific close routine. 327 * Detach the tty from the sl unit. 328 */ 329 static int 330 slclose(tp,flag) 331 struct tty *tp; 332 int flag; 333 { 334 register struct sl_softc *sc; 335 int s; 336 337 ttyflush(tp, FREAD | FWRITE); 338 /* 339 * XXX the placement of the following spl is misleading. tty 340 * interrupts must be blocked across line discipline switches 341 * and throughout closes to avoid races. 342 */ 343 s = splimp(); /* actually, max(spltty, splnet) */ 344 clist_free_cblocks(&tp->t_outq); 345 tp->t_line = 0; 346 sc = (struct sl_softc *)tp->t_sc; 347 if (sc != NULL) { 348 if (sc->sc_outfill) { 349 sc->sc_outfill = 0; 350 untimeout(sl_outfill, sc, sc->sc_ofhandle); 351 } 352 if (sc->sc_keepalive) { 353 sc->sc_keepalive = 0; 354 untimeout(sl_keepalive, sc, sc->sc_kahandle); 355 } 356 if_down(&sc->sc_if); 357 sc->sc_flags &= SC_STATIC; 358 sc->sc_ttyp = NULL; 359 tp->t_sc = NULL; 360 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE)); 361 sc->sc_ep = 0; 362 sc->sc_mp = 0; 363 sc->sc_buf = 0; 364 } 365 splx(s); 366 return 0; 367 } 368 369 /* 370 * Line specific (tty) ioctl routine. 371 * Provide a way to get the sl unit number. 372 */ 373 /* ARGSUSED */ 374 static int 375 sltioctl(tp, cmd, data, flag, p) 376 struct tty *tp; 377 u_long cmd; 378 caddr_t data; 379 int flag; 380 struct proc *p; 381 { 382 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc; 383 int s, nsl; 384 385 s = splimp(); 386 switch (cmd) { 387 case SLIOCGUNIT: 388 *(int *)data = sc->sc_if.if_unit; 389 break; 390 391 case SLIOCSUNIT: 392 if (sc->sc_if.if_unit != *(u_int *)data) { 393 for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) { 394 if ( nc->sc_if.if_unit == *(u_int *)data 395 && nc->sc_ttyp == NULL 396 ) { 397 tmpnc = malloc(sizeof *tmpnc, M_TEMP, 398 M_NOWAIT); 399 if (tmpnc == NULL) { 400 splx(s); 401 return (ENOMEM); 402 } 403 *tmpnc = *nc; 404 *nc = *sc; 405 nc->sc_if = tmpnc->sc_if; 406 tmpnc->sc_if = sc->sc_if; 407 *sc = *tmpnc; 408 free(tmpnc, M_TEMP); 409 if (sc->sc_if.if_flags & IFF_UP) { 410 if_down(&sc->sc_if); 411 if (!(nc->sc_if.if_flags & IFF_UP)) 412 if_up(&nc->sc_if); 413 } else if (nc->sc_if.if_flags & IFF_UP) 414 if_down(&nc->sc_if); 415 sc->sc_flags &= ~SC_STATIC; 416 sc->sc_flags |= (nc->sc_flags & SC_STATIC); 417 tp->t_sc = sc = nc; 418 clist_alloc_cblocks(&tp->t_outq, 419 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 420 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 421 sl_compress_init(&sc->sc_comp, -1); 422 goto slfound; 423 } 424 } 425 splx(s); 426 return (ENXIO); 427 } 428 slfound: 429 sc->sc_flags |= SC_STATIC; 430 break; 431 432 case SLIOCSKEEPAL: 433 sc->sc_keepalive = *(u_int *)data * hz; 434 if (sc->sc_keepalive) { 435 sc->sc_flags |= SC_KEEPALIVE; 436 sc->sc_kahandle = timeout(sl_keepalive, sc, 437 sc->sc_keepalive); 438 } else { 439 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 440 untimeout(sl_keepalive, sc, sc->sc_kahandle); 441 sc->sc_flags &= ~SC_KEEPALIVE; 442 } 443 } 444 break; 445 446 case SLIOCGKEEPAL: 447 *(int *)data = sc->sc_keepalive / hz; 448 break; 449 450 case SLIOCSOUTFILL: 451 sc->sc_outfill = *(u_int *)data * hz; 452 if (sc->sc_outfill) { 453 sc->sc_flags |= SC_OUTWAIT; 454 sc->sc_ofhandle = timeout(sl_outfill, sc, 455 sc->sc_outfill); 456 } else { 457 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 458 untimeout(sl_outfill, sc, sc->sc_ofhandle); 459 sc->sc_flags &= ~SC_OUTWAIT; 460 } 461 } 462 break; 463 464 case SLIOCGOUTFILL: 465 *(int *)data = sc->sc_outfill / hz; 466 break; 467 468 default: 469 splx(s); 470 return (ENOIOCTL); 471 } 472 splx(s); 473 return (0); 474 } 475 476 /* 477 * Queue a packet. Start transmission if not active. 478 * Compression happens in slstart; if we do it here, IP TOS 479 * will cause us to not compress "background" packets, because 480 * ordering gets trashed. It can be done for all packets in slstart. 481 */ 482 static int 483 sloutput(ifp, m, dst, rtp) 484 struct ifnet *ifp; 485 register struct mbuf *m; 486 struct sockaddr *dst; 487 struct rtentry *rtp; 488 { 489 register struct sl_softc *sc = &sl_softc[ifp->if_unit]; 490 register struct ip *ip; 491 register struct ifqueue *ifq; 492 int s; 493 494 /* 495 * `Cannot happen' (see slioctl). Someday we will extend 496 * the line protocol to support other address families. 497 */ 498 if (dst->sa_family != AF_INET) { 499 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit, 500 dst->sa_family); 501 m_freem(m); 502 sc->sc_if.if_noproto++; 503 return (EAFNOSUPPORT); 504 } 505 506 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 507 m_freem(m); 508 return (ENETDOWN); 509 } 510 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 511 m_freem(m); 512 return (EHOSTUNREACH); 513 } 514 ifq = &sc->sc_if.if_snd; 515 ip = mtod(m, struct ip *); 516 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 517 m_freem(m); 518 return (ENETRESET); /* XXX ? */ 519 } 520 if (ip->ip_tos & IPTOS_LOWDELAY) 521 ifq = &sc->sc_fastq; 522 s = splimp(); 523 if (IF_QFULL(ifq)) { 524 IF_DROP(ifq); 525 m_freem(m); 526 splx(s); 527 sc->sc_if.if_oerrors++; 528 return (ENOBUFS); 529 } 530 IF_ENQUEUE(ifq, m); 531 if (sc->sc_ttyp->t_outq.c_cc == 0) 532 slstart(sc->sc_ttyp); 533 splx(s); 534 return (0); 535 } 536 537 /* 538 * Start output on interface. Get another datagram 539 * to send from the interface queue and map it to 540 * the interface before starting output. 541 */ 542 static int 543 slstart(tp) 544 register struct tty *tp; 545 { 546 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 547 register struct mbuf *m; 548 register u_char *cp; 549 register struct ip *ip; 550 int s; 551 u_char bpfbuf[SLTMAX + SLIP_HDRLEN]; 552 register int len = 0; 553 554 for (;;) { 555 /* 556 * Call output process whether or not there is more in the 557 * output queue. We are being called in lieu of ttstart 558 * and must do what it would. 559 */ 560 (*tp->t_oproc)(tp); 561 562 if (tp->t_outq.c_cc != 0) { 563 if (sc != NULL) 564 sc->sc_flags &= ~SC_OUTWAIT; 565 if (tp->t_outq.c_cc > SLIP_HIWAT) 566 return 0; 567 } 568 569 /* 570 * This happens briefly when the line shuts down. 571 */ 572 if (sc == NULL) 573 return 0; 574 575 /* 576 * Get a packet and send it to the interface. 577 */ 578 s = splimp(); 579 IF_DEQUEUE(&sc->sc_fastq, m); 580 if (m) 581 sc->sc_if.if_omcasts++; /* XXX */ 582 else 583 IF_DEQUEUE(&sc->sc_if.if_snd, m); 584 splx(s); 585 if (m == NULL) 586 return 0; 587 588 /* 589 * We do the header compression here rather than in sloutput 590 * because the packets will be out of order if we are using TOS 591 * queueing, and the connection id compression will get 592 * munged when this happens. 593 */ 594 if (sc->sc_if.if_bpf) { 595 /* 596 * We need to save the TCP/IP header before it's 597 * compressed. To avoid complicated code, we just 598 * copy the entire packet into a stack buffer (since 599 * this is a serial line, packets should be short 600 * and/or the copy should be negligible cost compared 601 * to the packet transmission time). 602 */ 603 register struct mbuf *m1 = m; 604 register u_char *cp = bpfbuf + SLIP_HDRLEN; 605 606 len = 0; 607 do { 608 register int mlen = m1->m_len; 609 610 bcopy(mtod(m1, caddr_t), cp, mlen); 611 cp += mlen; 612 len += mlen; 613 } while ((m1 = m1->m_next) != NULL); 614 } 615 ip = mtod(m, struct ip *); 616 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 617 if (sc->sc_if.if_flags & SC_COMPRESS) 618 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 619 &sc->sc_comp, 1); 620 } 621 if (sc->sc_if.if_bpf) { 622 /* 623 * Put the SLIP pseudo-"link header" in place. The 624 * compressed header is now at the beginning of the 625 * mbuf. 626 */ 627 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 628 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 629 bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN); 630 } 631 632 /* 633 * If system is getting low on clists, just flush our 634 * output queue (if the stuff was important, it'll get 635 * retransmitted). Note that SLTMAX is used instead of 636 * the current if_mtu setting because connections that 637 * have already been established still use the original 638 * (possibly larger) mss. 639 */ 640 if (cfreecount < CLISTRESERVE + SLTMAX) { 641 m_freem(m); 642 sc->sc_if.if_collisions++; 643 continue; 644 } 645 646 sc->sc_flags &= ~SC_OUTWAIT; 647 /* 648 * The extra FRAME_END will start up a new packet, and thus 649 * will flush any accumulated garbage. We do this whenever 650 * the line may have been idle for some time. 651 */ 652 if (tp->t_outq.c_cc == 0) { 653 ++sc->sc_if.if_obytes; 654 (void) putc(FRAME_END, &tp->t_outq); 655 } 656 657 while (m) { 658 register u_char *ep; 659 660 cp = mtod(m, u_char *); ep = cp + m->m_len; 661 while (cp < ep) { 662 /* 663 * Find out how many bytes in the string we can 664 * handle without doing something special. 665 */ 666 register u_char *bp = cp; 667 668 while (cp < ep) { 669 switch (*cp++) { 670 case FRAME_ESCAPE: 671 case FRAME_END: 672 --cp; 673 goto out; 674 } 675 } 676 out: 677 if (cp > bp) { 678 /* 679 * Put n characters at once 680 * into the tty output queue. 681 */ 682 if (b_to_q((char *)bp, cp - bp, 683 &tp->t_outq)) 684 break; 685 sc->sc_if.if_obytes += cp - bp; 686 } 687 /* 688 * If there are characters left in the mbuf, 689 * the first one must be special.. 690 * Put it out in a different form. 691 */ 692 if (cp < ep) { 693 if (putc(FRAME_ESCAPE, &tp->t_outq)) 694 break; 695 if (putc(*cp++ == FRAME_ESCAPE ? 696 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 697 &tp->t_outq)) { 698 (void) unputc(&tp->t_outq); 699 break; 700 } 701 sc->sc_if.if_obytes += 2; 702 } 703 } 704 m = m_free(m); 705 } 706 707 if (putc(FRAME_END, &tp->t_outq)) { 708 /* 709 * Not enough room. Remove a char to make room 710 * and end the packet normally. 711 * If you get many collisions (more than one or two 712 * a day) you probably do not have enough clists 713 * and you should increase "nclist" in param.c. 714 */ 715 (void) unputc(&tp->t_outq); 716 (void) putc(FRAME_END, &tp->t_outq); 717 sc->sc_if.if_collisions++; 718 } else { 719 ++sc->sc_if.if_obytes; 720 sc->sc_if.if_opackets++; 721 } 722 } 723 return 0; 724 } 725 726 /* 727 * Copy data buffer to mbuf chain; add ifnet pointer. 728 */ 729 static struct mbuf * 730 sl_btom(sc, len) 731 register struct sl_softc *sc; 732 register int len; 733 { 734 register struct mbuf *m; 735 736 MGETHDR(m, M_DONTWAIT, MT_DATA); 737 if (m == NULL) 738 return (NULL); 739 740 /* 741 * If we have more than MHLEN bytes, it's cheaper to 742 * queue the cluster we just filled & allocate a new one 743 * for the input buffer. Otherwise, fill the mbuf we 744 * allocated above. Note that code in the input routine 745 * guarantees that packet will fit in a cluster. 746 */ 747 if (len >= MHLEN) { 748 MCLGET(m, M_DONTWAIT); 749 if ((m->m_flags & M_EXT) == 0) { 750 /* 751 * we couldn't get a cluster - if memory's this 752 * low, it's time to start dropping packets. 753 */ 754 (void) m_free(m); 755 return (NULL); 756 } 757 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 758 m->m_data = (caddr_t)sc->sc_buf; 759 m->m_ext.ext_buf = (caddr_t)((intptr_t)sc->sc_buf &~ MCLOFSET); 760 } else 761 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 762 763 m->m_len = len; 764 m->m_pkthdr.len = len; 765 m->m_pkthdr.rcvif = &sc->sc_if; 766 return (m); 767 } 768 769 /* 770 * tty interface receiver interrupt. 771 */ 772 static int 773 slinput(c, tp) 774 register int c; 775 register struct tty *tp; 776 { 777 register struct sl_softc *sc; 778 register struct mbuf *m; 779 register int len; 780 int s; 781 u_char chdr[CHDR_LEN]; 782 783 tk_nin++; 784 sc = (struct sl_softc *)tp->t_sc; 785 if (sc == NULL) 786 return 0; 787 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 788 sc->sc_flags |= SC_ERROR; 789 return 0; 790 } 791 c &= TTY_CHARMASK; 792 793 ++sc->sc_if.if_ibytes; 794 795 if (sc->sc_if.if_flags & IFF_DEBUG) { 796 if (c == ABT_ESC) { 797 /* 798 * If we have a previous abort, see whether 799 * this one is within the time limit. 800 */ 801 if (sc->sc_abortcount && 802 time_second >= sc->sc_starttime + ABT_WINDOW) 803 sc->sc_abortcount = 0; 804 /* 805 * If we see an abort after "idle" time, count it; 806 * record when the first abort escape arrived. 807 */ 808 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 809 if (++sc->sc_abortcount == 1) 810 sc->sc_starttime = time_second; 811 if (sc->sc_abortcount >= ABT_COUNT) { 812 slclose(tp,0); 813 return 0; 814 } 815 } 816 } else 817 sc->sc_abortcount = 0; 818 sc->sc_lasttime = time_second; 819 } 820 821 switch (c) { 822 823 case TRANS_FRAME_ESCAPE: 824 if (sc->sc_escape) 825 c = FRAME_ESCAPE; 826 break; 827 828 case TRANS_FRAME_END: 829 if (sc->sc_escape) 830 c = FRAME_END; 831 break; 832 833 case FRAME_ESCAPE: 834 sc->sc_escape = 1; 835 return 0; 836 837 case FRAME_END: 838 sc->sc_flags &= ~SC_KEEPALIVE; 839 if(sc->sc_flags & SC_ERROR) { 840 sc->sc_flags &= ~SC_ERROR; 841 goto newpack; 842 } 843 len = sc->sc_mp - sc->sc_buf; 844 if (len < 3) 845 /* less than min length packet - ignore */ 846 goto newpack; 847 848 if (sc->sc_if.if_bpf) { 849 /* 850 * Save the compressed header, so we 851 * can tack it on later. Note that we 852 * will end up copying garbage in some 853 * cases but this is okay. We remember 854 * where the buffer started so we can 855 * compute the new header length. 856 */ 857 bcopy(sc->sc_buf, chdr, CHDR_LEN); 858 } 859 860 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 861 if (c & 0x80) 862 c = TYPE_COMPRESSED_TCP; 863 else if (c == TYPE_UNCOMPRESSED_TCP) 864 *sc->sc_buf &= 0x4f; /* XXX */ 865 /* 866 * We've got something that's not an IP packet. 867 * If compression is enabled, try to decompress it. 868 * Otherwise, if `auto-enable' compression is on and 869 * it's a reasonable packet, decompress it and then 870 * enable compression. Otherwise, drop it. 871 */ 872 if (sc->sc_if.if_flags & SC_COMPRESS) { 873 len = sl_uncompress_tcp(&sc->sc_buf, len, 874 (u_int)c, &sc->sc_comp); 875 if (len <= 0) 876 goto error; 877 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 878 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 879 len = sl_uncompress_tcp(&sc->sc_buf, len, 880 (u_int)c, &sc->sc_comp); 881 if (len <= 0) 882 goto error; 883 sc->sc_if.if_flags |= SC_COMPRESS; 884 } else 885 goto error; 886 } 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 m = sl_btom(sc, len); 901 if (m == NULL) 902 goto error; 903 904 sc->sc_if.if_ipackets++; 905 906 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 907 m_freem(m); 908 goto newpack; 909 } 910 911 s = splimp(); 912 if (IF_QFULL(&ipintrq)) { 913 IF_DROP(&ipintrq); 914 sc->sc_if.if_ierrors++; 915 sc->sc_if.if_iqdrops++; 916 m_freem(m); 917 } else { 918 IF_ENQUEUE(&ipintrq, m); 919 schednetisr(NETISR_IP); 920 } 921 splx(s); 922 goto newpack; 923 } 924 if (sc->sc_mp < sc->sc_ep) { 925 *sc->sc_mp++ = c; 926 sc->sc_escape = 0; 927 return 0; 928 } 929 930 /* can't put lower; would miss an extra frame */ 931 sc->sc_flags |= SC_ERROR; 932 933 error: 934 sc->sc_if.if_ierrors++; 935 newpack: 936 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 937 sc->sc_escape = 0; 938 return 0; 939 } 940 941 /* 942 * Process an ioctl request. 943 */ 944 static int 945 slioctl(ifp, cmd, data) 946 register struct ifnet *ifp; 947 u_long cmd; 948 caddr_t data; 949 { 950 register struct ifaddr *ifa = (struct ifaddr *)data; 951 register struct ifreq *ifr = (struct ifreq *)data; 952 register int s, error = 0; 953 954 s = splimp(); 955 956 switch (cmd) { 957 958 case SIOCSIFFLAGS: 959 /* 960 * if.c will set the interface up even if we 961 * don't want it to. 962 */ 963 if (sl_softc[ifp->if_unit].sc_ttyp == NULL) { 964 ifp->if_flags &= ~IFF_UP; 965 } 966 break; 967 case SIOCSIFADDR: 968 /* 969 * This is "historical" - set the interface up when 970 * setting the address. 971 */ 972 if (ifa->ifa_addr->sa_family == AF_INET) { 973 if (sl_softc[ifp->if_unit].sc_ttyp != NULL) 974 ifp->if_flags |= IFF_UP; 975 } else { 976 error = EAFNOSUPPORT; 977 } 978 break; 979 980 case SIOCSIFDSTADDR: 981 if (ifa->ifa_addr->sa_family != AF_INET) 982 error = EAFNOSUPPORT; 983 break; 984 985 case SIOCADDMULTI: 986 case SIOCDELMULTI: 987 break; 988 989 case SIOCSIFMTU: 990 /* 991 * Set the interface MTU. 992 */ 993 if (ifr->ifr_mtu > SLTMAX) 994 error = EINVAL; 995 else { 996 struct tty *tp; 997 998 ifp->if_mtu = ifr->ifr_mtu; 999 tp = sl_softc[ifp->if_unit].sc_ttyp; 1000 if (tp != NULL) 1001 clist_alloc_cblocks(&tp->t_outq, 1002 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1003 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1004 } 1005 break; 1006 1007 default: 1008 error = EINVAL; 1009 } 1010 splx(s); 1011 return (error); 1012 } 1013 1014 static void 1015 sl_keepalive(chan) 1016 void *chan; 1017 { 1018 struct sl_softc *sc = chan; 1019 1020 if (sc->sc_keepalive) { 1021 if (sc->sc_flags & SC_KEEPALIVE) 1022 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1023 else 1024 sc->sc_flags |= SC_KEEPALIVE; 1025 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1026 } else { 1027 sc->sc_flags &= ~SC_KEEPALIVE; 1028 } 1029 } 1030 1031 static void 1032 sl_outfill(chan) 1033 void *chan; 1034 { 1035 struct sl_softc *sc = chan; 1036 register struct tty *tp = sc->sc_ttyp; 1037 int s; 1038 1039 if (sc->sc_outfill && tp != NULL) { 1040 if (sc->sc_flags & SC_OUTWAIT) { 1041 s = splimp (); 1042 ++sc->sc_if.if_obytes; 1043 (void) putc(FRAME_END, &tp->t_outq); 1044 (*tp->t_oproc)(tp); 1045 splx (s); 1046 } else 1047 sc->sc_flags |= SC_OUTWAIT; 1048 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1049 } else { 1050 sc->sc_flags &= ~SC_OUTWAIT; 1051 } 1052 }
Cache object: b7c735ed4beebe906472fba7666aad50
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