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: releng/5.0/sys/net/if_sl.c 106939 2002-11-15 00:00:15Z sam $ 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 "opt_inet.h" 69 #include "opt_slip.h" 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/malloc.h> 74 #include <sys/mbuf.h> 75 #include <sys/proc.h> 76 #include <sys/dkstat.h> 77 #include <sys/socket.h> 78 #include <sys/sockio.h> 79 #include <sys/fcntl.h> 80 #include <sys/signalvar.h> 81 #include <sys/tty.h> 82 #include <sys/clist.h> 83 #include <sys/kernel.h> 84 #include <sys/conf.h> 85 #include <sys/module.h> 86 #include <sys/proc.h> 87 88 #include <net/if.h> 89 #include <net/if_types.h> 90 #include <net/netisr.h> 91 92 #if INET 93 #include <netinet/in.h> 94 #include <netinet/in_systm.h> 95 #include <netinet/in_var.h> 96 #include <netinet/ip.h> 97 #else 98 #error "Huh? Slip without inet?" 99 #endif 100 101 #include <net/slcompress.h> 102 #include <net/if_slvar.h> 103 #include <net/slip.h> 104 105 #include <net/bpf.h> 106 107 static MALLOC_DEFINE(M_SL, "sl", "SLIP Interface"); 108 109 /* 110 * SLRMAX is a hard limit on input packet size. To simplify the code 111 * and improve performance, we require that packets fit in an mbuf 112 * cluster, and if we get a compressed packet, there's enough extra 113 * room to expand the header into a max length tcp/ip header (128 114 * bytes). So, SLRMAX can be at most 115 * MCLBYTES - 128 116 * 117 * SLMTU is the default transmit MTU. The transmit MTU should be kept 118 * small enough so that interactive use doesn't suffer, but large 119 * enough to provide good performance. 552 is a good choice for SLMTU 120 * because it is high enough to not fragment TCP packets being routed 121 * through this host. Packet fragmentation is bad with SLIP because 122 * fragment headers aren't compressed. The previous assumptions about 123 * the best MTU value don't really hold when using modern modems with 124 * BTLZ data compression because the modem buffers play a much larger 125 * role in interactive performance than the MTU. The MTU can be changed 126 * at any time to suit the specific environment with ifconfig(8), and 127 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 128 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 129 * handles this better). 130 * 131 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 132 * of us (i.e., in clists waiting to be picked up by the tty output 133 * interrupt). If we queue a lot of data downstream, it's immune to 134 * our t.o.s. queuing. 135 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 136 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 137 * wait is dependent on the ftp window size but that's typically 138 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 139 * the cost (in idle time on the wire) of the tty driver running 140 * off the end of its clists & having to call back slstart for a 141 * new packet. For a tty interface with any buffering at all, this 142 * cost will be zero. Even with a totally brain dead interface (like 143 * the one on a typical workstation), the cost will be <= 1 character 144 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 145 * at most 1% while maintaining good interactive response. 146 */ 147 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 148 #define SLRMAX (MCLBYTES - BUFOFFSET) 149 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 150 #ifndef SLMTU 151 #define SLMTU 552 /* default MTU */ 152 #endif 153 #define SLTMAX 1500 /* maximum MTU */ 154 #define SLIP_HIWAT roundup(50,CBSIZE) 155 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 156 157 /* 158 * SLIP ABORT ESCAPE MECHANISM: 159 * (inspired by HAYES modem escape arrangement) 160 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 161 * within window time signals a "soft" exit from slip mode by remote end 162 * if the IFF_DEBUG flag is on. 163 */ 164 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 165 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 166 #define ABT_COUNT 3 /* count of escapes for abort */ 167 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 168 169 static LIST_HEAD(sl_list, sl_softc) sl_list; 170 171 #define FRAME_END 0xc0 /* Frame End */ 172 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 173 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 174 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 175 176 static int slisstatic(int); 177 static void slmarkstatic(int); 178 static struct sl_softc *slcreate(void); 179 static void sldestroy(struct sl_softc *sc); 180 static struct mbuf *sl_btom(struct sl_softc *, int); 181 static timeout_t sl_keepalive; 182 static timeout_t sl_outfill; 183 static l_close_t slclose; 184 static l_rint_t slinput; 185 static l_ioctl_t sltioctl; 186 static int slioctl(struct ifnet *, u_long, caddr_t); 187 static int slopen(dev_t, struct tty *); 188 static int sloutput(struct ifnet *, 189 struct mbuf *, struct sockaddr *, struct rtentry *); 190 static int slstart(struct tty *); 191 192 static struct linesw slipdisc = { 193 slopen, slclose, l_noread, l_nowrite, 194 sltioctl, slinput, slstart, ttymodem, 195 FRAME_END 196 }; 197 198 /* 199 * Called from boot code to establish sl interfaces. 200 */ 201 static int 202 sl_modevent(module_t mod, int type, void *data) 203 { 204 switch (type) { 205 case MOD_LOAD: 206 linesw[SLIPDISC] = slipdisc; 207 LIST_INIT(&sl_list); 208 break; 209 case MOD_UNLOAD: 210 printf("if_sl module unload - not possible for this module type\n"); 211 return EINVAL; 212 } 213 return 0; 214 } 215 216 static moduledata_t sl_mod = { 217 "if_sl", 218 sl_modevent, 219 0 220 }; 221 222 DECLARE_MODULE(if_sl, sl_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 223 224 static int *st_unit_list; 225 static size_t st_unit_max = 0; 226 227 static int 228 slisstatic(unit) 229 int unit; 230 { 231 size_t i; 232 233 for (i = 0; i < st_unit_max; i++) 234 if (st_unit_list[i] == unit) 235 return 1; 236 return 0; 237 } 238 239 static void 240 slmarkstatic(unit) 241 int unit; 242 { 243 int *t; 244 245 if (slisstatic(unit)) 246 return; 247 248 MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT); 249 if (t == NULL) 250 return; 251 252 if (st_unit_list) { 253 bcopy(st_unit_list, t, sizeof(int) * st_unit_max); 254 free(st_unit_list, M_SL); 255 } 256 st_unit_list = t; 257 st_unit_list[st_unit_max] = unit; 258 st_unit_max++; 259 } 260 261 static struct sl_softc * 262 slcreate() 263 { 264 struct sl_softc *sc, *nc; 265 int unit; 266 struct mbuf *m; 267 268 MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO); 269 270 m = m_gethdr(M_TRYWAIT, MT_DATA); 271 if (m != NULL) { 272 MCLGET(m, M_TRYWAIT); 273 if ((m->m_flags & M_EXT) == 0) { 274 m_free(m); 275 m = NULL; 276 } 277 } 278 279 if (m == NULL) { 280 printf("sl: can't allocate buffer\n"); 281 free(sc, M_SL); 282 return (NULL); 283 } 284 285 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 286 sc->sc_mbuf = m; 287 sc->sc_buf = sc->sc_ep - SLRMAX; 288 sc->sc_mp = sc->sc_buf; 289 sl_compress_init(&sc->sc_comp, -1); 290 291 sc->sc_if.if_softc = sc; 292 sc->sc_if.if_name = "sl"; 293 sc->sc_if.if_mtu = SLMTU; 294 sc->sc_if.if_flags = 295 #ifdef SLIP_IFF_OPTS 296 SLIP_IFF_OPTS; 297 #else 298 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 299 #endif 300 sc->sc_if.if_type = IFT_SLIP; 301 sc->sc_if.if_ioctl = slioctl; 302 sc->sc_if.if_output = sloutput; 303 sc->sc_if.if_snd.ifq_maxlen = 50; 304 sc->sc_fastq.ifq_maxlen = 32; 305 sc->sc_if.if_linkmib = sc; 306 sc->sc_if.if_linkmiblen = sizeof *sc; 307 mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF); 308 309 /* 310 * Find a suitable unit number. 311 */ 312 for (unit=0; ; unit++) { 313 if (slisstatic(unit)) 314 continue; 315 LIST_FOREACH(nc, &sl_list, sl_next) { 316 if (nc->sc_if.if_unit == unit) 317 continue; 318 } 319 break; 320 } 321 sc->sc_if.if_unit = unit; 322 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 323 324 if_attach(&sc->sc_if); 325 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 326 327 return sc; 328 } 329 330 331 /* 332 * Line specific open routine. 333 * Attach the given tty to the first available sl unit. 334 */ 335 /* ARGSUSED */ 336 static int 337 slopen(dev, tp) 338 dev_t dev; 339 register struct tty *tp; 340 { 341 register struct sl_softc *sc; 342 int s, error; 343 344 error = suser(curthread); 345 if (error) 346 return (error); 347 348 if (tp->t_line == SLIPDISC) 349 return (0); 350 351 if ((sc = slcreate()) == NULL) 352 return (ENOBUFS); 353 354 tp->t_sc = (caddr_t)sc; 355 sc->sc_ttyp = tp; 356 sc->sc_if.if_baudrate = tp->t_ospeed; 357 ttyflush(tp, FREAD | FWRITE); 358 tp->t_line = SLIPDISC; 359 360 /* 361 * We don't use t_canq or t_rawq, so reduce their 362 * cblock resources to 0. Reserve enough cblocks 363 * for t_outq to guarantee that we can fit a full 364 * packet if the SLIP_HIWAT check allows slstart() 365 * to loop. Use the same value for the cblock 366 * limit since the reserved blocks should always 367 * be enough. Reserving cblocks probably makes 368 * the CLISTRESERVE check unnecessary and wasteful. 369 */ 370 clist_alloc_cblocks(&tp->t_canq, 0, 0); 371 clist_alloc_cblocks(&tp->t_outq, 372 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 373 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 374 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 375 376 s = splnet(); 377 if_up(&sc->sc_if); 378 splx(s); 379 return (0); 380 } 381 382 static void 383 sldestroy(struct sl_softc *sc) 384 { 385 bpfdetach(&sc->sc_if); 386 if_detach(&sc->sc_if); 387 LIST_REMOVE(sc, sl_next); 388 m_free(sc->sc_mbuf); 389 mtx_destroy(&sc->sc_fastq.ifq_mtx); 390 if (sc->bpfbuf) 391 free(sc->bpfbuf, M_SL); 392 free(sc, M_SL); 393 } 394 395 /* 396 * Line specific close routine. 397 * Detach the tty from the sl unit. 398 */ 399 static int 400 slclose(tp,flag) 401 struct tty *tp; 402 int flag; 403 { 404 register struct sl_softc *sc; 405 int s; 406 407 ttyflush(tp, FREAD | FWRITE); 408 /* 409 * XXX the placement of the following spl is misleading. tty 410 * interrupts must be blocked across line discipline switches 411 * and throughout closes to avoid races. 412 */ 413 s = splimp(); /* actually, max(spltty, splnet) */ 414 clist_free_cblocks(&tp->t_outq); 415 tp->t_line = 0; 416 sc = (struct sl_softc *)tp->t_sc; 417 if (sc != NULL) { 418 if (sc->sc_outfill) { 419 sc->sc_outfill = 0; 420 untimeout(sl_outfill, sc, sc->sc_ofhandle); 421 } 422 if (sc->sc_keepalive) { 423 sc->sc_keepalive = 0; 424 untimeout(sl_keepalive, sc, sc->sc_kahandle); 425 } 426 if_down(&sc->sc_if); 427 sc->sc_ttyp = NULL; 428 tp->t_sc = NULL; 429 sldestroy(sc); 430 } 431 splx(s); 432 return 0; 433 } 434 435 /* 436 * Line specific (tty) ioctl routine. 437 * Provide a way to get the sl unit number. 438 */ 439 /* ARGSUSED */ 440 static int 441 sltioctl(tp, cmd, data, flag, td) 442 struct tty *tp; 443 u_long cmd; 444 caddr_t data; 445 int flag; 446 struct thread *td; 447 { 448 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc; 449 int s, unit, wasup; 450 451 s = splimp(); 452 switch (cmd) { 453 case SLIOCGUNIT: 454 *(int *)data = sc->sc_if.if_unit; 455 break; 456 457 case SLIOCSUNIT: 458 unit = *(u_int *)data; 459 if (unit < 0) { 460 splx(s); 461 return (ENXIO); 462 } 463 if (sc->sc_if.if_unit != unit) { 464 LIST_FOREACH(nc, &sl_list, sl_next) { 465 if (nc->sc_if.if_unit == *(u_int *)data) { 466 splx(s); 467 return (ENXIO); 468 } 469 } 470 471 wasup = sc->sc_if.if_flags & IFF_UP; 472 bpfdetach(&sc->sc_if); 473 if_detach(&sc->sc_if); 474 LIST_REMOVE(sc, sl_next); 475 sc->sc_if.if_unit = unit; 476 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 477 if_attach(&sc->sc_if); 478 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 479 if (wasup) 480 if_up(&sc->sc_if); 481 else 482 if_down(&sc->sc_if); 483 clist_alloc_cblocks(&tp->t_outq, 484 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 485 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 486 } 487 slmarkstatic(unit); 488 break; 489 490 case SLIOCSKEEPAL: 491 sc->sc_keepalive = *(u_int *)data * hz; 492 if (sc->sc_keepalive) { 493 sc->sc_flags |= SC_KEEPALIVE; 494 sc->sc_kahandle = timeout(sl_keepalive, sc, 495 sc->sc_keepalive); 496 } else { 497 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 498 untimeout(sl_keepalive, sc, sc->sc_kahandle); 499 sc->sc_flags &= ~SC_KEEPALIVE; 500 } 501 } 502 break; 503 504 case SLIOCGKEEPAL: 505 *(int *)data = sc->sc_keepalive / hz; 506 break; 507 508 case SLIOCSOUTFILL: 509 sc->sc_outfill = *(u_int *)data * hz; 510 if (sc->sc_outfill) { 511 sc->sc_flags |= SC_OUTWAIT; 512 sc->sc_ofhandle = timeout(sl_outfill, sc, 513 sc->sc_outfill); 514 } else { 515 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 516 untimeout(sl_outfill, sc, sc->sc_ofhandle); 517 sc->sc_flags &= ~SC_OUTWAIT; 518 } 519 } 520 break; 521 522 case SLIOCGOUTFILL: 523 *(int *)data = sc->sc_outfill / hz; 524 break; 525 526 default: 527 splx(s); 528 return (ENOIOCTL); 529 } 530 splx(s); 531 return (0); 532 } 533 534 /* 535 * Queue a packet. Start transmission if not active. 536 * Compression happens in slstart; if we do it here, IP TOS 537 * will cause us to not compress "background" packets, because 538 * ordering gets trashed. It can be done for all packets in slstart. 539 */ 540 static int 541 sloutput(ifp, m, dst, rtp) 542 struct ifnet *ifp; 543 register struct mbuf *m; 544 struct sockaddr *dst; 545 struct rtentry *rtp; 546 { 547 register struct sl_softc *sc = ifp->if_softc; 548 register struct ip *ip; 549 register struct ifqueue *ifq; 550 int s; 551 552 /* 553 * `Cannot happen' (see slioctl). Someday we will extend 554 * the line protocol to support other address families. 555 */ 556 if (dst->sa_family != AF_INET) { 557 if_printf(ifp, "af%d not supported\n", dst->sa_family); 558 m_freem(m); 559 sc->sc_if.if_noproto++; 560 return (EAFNOSUPPORT); 561 } 562 563 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 564 m_freem(m); 565 return (ENETDOWN); 566 } 567 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 568 m_freem(m); 569 return (EHOSTUNREACH); 570 } 571 ifq = &sc->sc_if.if_snd; 572 ip = mtod(m, struct ip *); 573 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 574 m_freem(m); 575 return (ENETRESET); /* XXX ? */ 576 } 577 if (ip->ip_tos & IPTOS_LOWDELAY) 578 ifq = &sc->sc_fastq; 579 if (! IF_HANDOFF(ifq, m, NULL)) { 580 sc->sc_if.if_oerrors++; 581 return (ENOBUFS); 582 } 583 s = splimp(); 584 if (sc->sc_ttyp->t_outq.c_cc == 0) 585 slstart(sc->sc_ttyp); 586 splx(s); 587 return (0); 588 } 589 590 /* 591 * Start output on interface. Get another datagram 592 * to send from the interface queue and map it to 593 * the interface before starting output. 594 */ 595 static int 596 slstart(tp) 597 register struct tty *tp; 598 { 599 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 600 register struct mbuf *m; 601 register u_char *cp; 602 register struct ip *ip; 603 int s; 604 register int len = 0; 605 606 for (;;) { 607 /* 608 * Call output process whether or not there is more in the 609 * output queue. We are being called in lieu of ttstart 610 * and must do what it would. 611 */ 612 (*tp->t_oproc)(tp); 613 614 if (tp->t_outq.c_cc != 0) { 615 if (sc != NULL) 616 sc->sc_flags &= ~SC_OUTWAIT; 617 if (tp->t_outq.c_cc > SLIP_HIWAT) 618 return 0; 619 } 620 621 /* 622 * This happens briefly when the line shuts down. 623 */ 624 if (sc == NULL) 625 return 0; 626 627 /* 628 * Get a packet and send it to the interface. 629 */ 630 s = splimp(); 631 IF_DEQUEUE(&sc->sc_fastq, m); 632 if (m) 633 sc->sc_if.if_omcasts++; /* XXX */ 634 else 635 IF_DEQUEUE(&sc->sc_if.if_snd, m); 636 splx(s); 637 if (m == NULL) 638 return 0; 639 640 /* 641 * We do the header compression here rather than in sloutput 642 * because the packets will be out of order if we are using TOS 643 * queueing, and the connection id compression will get 644 * munged when this happens. 645 */ 646 if (sc->sc_if.if_bpf) { 647 /* 648 * We need to save the TCP/IP header before it's 649 * compressed. To avoid complicated code, we just 650 * copy the entire packet into a stack buffer (since 651 * this is a serial line, packets should be short 652 * and/or the copy should be negligible cost compared 653 * to the packet transmission time). 654 */ 655 register struct mbuf *m1 = m; 656 register u_char *cp; 657 658 if (sc->bpfbuf == NULL) 659 MALLOC(sc->bpfbuf, u_char *, 660 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT); 661 662 if (sc->bpfbuf) { 663 cp = sc->bpfbuf + SLIP_HDRLEN; 664 len = 0; 665 do { 666 register int mlen = m1->m_len; 667 668 bcopy(mtod(m1, caddr_t), cp, mlen); 669 cp += mlen; 670 len += mlen; 671 } while ((m1 = m1->m_next) != NULL); 672 } 673 } 674 ip = mtod(m, struct ip *); 675 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 676 if (sc->sc_if.if_flags & SC_COMPRESS) 677 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 678 &sc->sc_comp, 1); 679 } 680 if (sc->sc_if.if_bpf && sc->bpfbuf) { 681 /* 682 * Put the SLIP pseudo-"link header" in place. The 683 * compressed header is now at the beginning of the 684 * mbuf. 685 */ 686 sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT; 687 bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN); 688 BPF_TAP(&sc->sc_if, sc->bpfbuf, len + SLIP_HDRLEN); 689 } 690 691 /* 692 * If system is getting low on clists, just flush our 693 * output queue (if the stuff was important, it'll get 694 * retransmitted). Note that SLTMAX is used instead of 695 * the current if_mtu setting because connections that 696 * have already been established still use the original 697 * (possibly larger) mss. 698 */ 699 if (cfreecount < CLISTRESERVE + SLTMAX) { 700 m_freem(m); 701 sc->sc_if.if_collisions++; 702 continue; 703 } 704 705 sc->sc_flags &= ~SC_OUTWAIT; 706 /* 707 * The extra FRAME_END will start up a new packet, and thus 708 * will flush any accumulated garbage. We do this whenever 709 * the line may have been idle for some time. 710 */ 711 if (tp->t_outq.c_cc == 0) { 712 ++sc->sc_if.if_obytes; 713 (void) putc(FRAME_END, &tp->t_outq); 714 } 715 716 while (m) { 717 register u_char *ep; 718 719 cp = mtod(m, u_char *); ep = cp + m->m_len; 720 while (cp < ep) { 721 /* 722 * Find out how many bytes in the string we can 723 * handle without doing something special. 724 */ 725 register u_char *bp = cp; 726 727 while (cp < ep) { 728 switch (*cp++) { 729 case FRAME_ESCAPE: 730 case FRAME_END: 731 --cp; 732 goto out; 733 } 734 } 735 out: 736 if (cp > bp) { 737 /* 738 * Put n characters at once 739 * into the tty output queue. 740 */ 741 if (b_to_q((char *)bp, cp - bp, 742 &tp->t_outq)) 743 break; 744 sc->sc_if.if_obytes += cp - bp; 745 } 746 /* 747 * If there are characters left in the mbuf, 748 * the first one must be special.. 749 * Put it out in a different form. 750 */ 751 if (cp < ep) { 752 if (putc(FRAME_ESCAPE, &tp->t_outq)) 753 break; 754 if (putc(*cp++ == FRAME_ESCAPE ? 755 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 756 &tp->t_outq)) { 757 (void) unputc(&tp->t_outq); 758 break; 759 } 760 sc->sc_if.if_obytes += 2; 761 } 762 } 763 m = m_free(m); 764 } 765 766 if (putc(FRAME_END, &tp->t_outq)) { 767 /* 768 * Not enough room. Remove a char to make room 769 * and end the packet normally. 770 * If you get many collisions (more than one or two 771 * a day) you probably do not have enough clists 772 * and you should increase "nclist" in param.c. 773 */ 774 (void) unputc(&tp->t_outq); 775 (void) putc(FRAME_END, &tp->t_outq); 776 sc->sc_if.if_collisions++; 777 } else { 778 ++sc->sc_if.if_obytes; 779 sc->sc_if.if_opackets++; 780 } 781 } 782 return 0; 783 } 784 785 /* 786 * Copy data buffer to mbuf chain; add ifnet pointer. 787 */ 788 static struct mbuf * 789 sl_btom(sc, len) 790 register struct sl_softc *sc; 791 register int len; 792 { 793 struct mbuf *m, *newm; 794 795 MGETHDR(m, M_DONTWAIT, MT_DATA); 796 if (m == NULL) 797 return (NULL); 798 799 /* 800 * If we have more than MHLEN bytes, it's cheaper to 801 * queue the cluster we just filled & allocate a new one 802 * for the input buffer. Otherwise, fill the mbuf we 803 * allocated above. Note that code in the input routine 804 * guarantees that packet will fit in a cluster. 805 */ 806 if (len >= MHLEN) { 807 MCLGET(m, M_DONTWAIT); 808 if ((m->m_flags & M_EXT) == 0) { 809 /* 810 * we couldn't get a cluster - if memory's this 811 * low, it's time to start dropping packets. 812 */ 813 (void) m_free(m); 814 return (NULL); 815 } 816 /* Swap the new and old clusters */ 817 newm = m; 818 m = sc->sc_mbuf; 819 sc->sc_mbuf = newm; 820 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE; 821 822 m->m_data = (caddr_t)sc->sc_buf; 823 } else 824 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 825 826 m->m_len = len; 827 m->m_pkthdr.len = len; 828 m->m_pkthdr.rcvif = &sc->sc_if; 829 return (m); 830 } 831 832 /* 833 * tty interface receiver interrupt. 834 */ 835 static int 836 slinput(c, tp) 837 register int c; 838 register struct tty *tp; 839 { 840 register struct sl_softc *sc; 841 register struct mbuf *m; 842 register int len; 843 u_char chdr[CHDR_LEN]; 844 845 tk_nin++; 846 sc = (struct sl_softc *)tp->t_sc; 847 if (sc == NULL) 848 return 0; 849 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 850 sc->sc_flags |= SC_ERROR; 851 return 0; 852 } 853 c &= TTY_CHARMASK; 854 855 ++sc->sc_if.if_ibytes; 856 857 if (sc->sc_if.if_flags & IFF_DEBUG) { 858 if (c == ABT_ESC) { 859 /* 860 * If we have a previous abort, see whether 861 * this one is within the time limit. 862 */ 863 if (sc->sc_abortcount && 864 time_second >= sc->sc_starttime + ABT_WINDOW) 865 sc->sc_abortcount = 0; 866 /* 867 * If we see an abort after "idle" time, count it; 868 * record when the first abort escape arrived. 869 */ 870 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 871 if (++sc->sc_abortcount == 1) 872 sc->sc_starttime = time_second; 873 if (sc->sc_abortcount >= ABT_COUNT) { 874 slclose(tp,0); 875 return 0; 876 } 877 } 878 } else 879 sc->sc_abortcount = 0; 880 sc->sc_lasttime = time_second; 881 } 882 883 switch (c) { 884 885 case TRANS_FRAME_ESCAPE: 886 if (sc->sc_escape) 887 c = FRAME_ESCAPE; 888 break; 889 890 case TRANS_FRAME_END: 891 if (sc->sc_escape) 892 c = FRAME_END; 893 break; 894 895 case FRAME_ESCAPE: 896 sc->sc_escape = 1; 897 return 0; 898 899 case FRAME_END: 900 sc->sc_flags &= ~SC_KEEPALIVE; 901 if(sc->sc_flags & SC_ERROR) { 902 sc->sc_flags &= ~SC_ERROR; 903 goto newpack; 904 } 905 len = sc->sc_mp - sc->sc_buf; 906 if (len < 3) 907 /* less than min length packet - ignore */ 908 goto newpack; 909 910 if (sc->sc_if.if_bpf) { 911 /* 912 * Save the compressed header, so we 913 * can tack it on later. Note that we 914 * will end up copying garbage in some 915 * cases but this is okay. We remember 916 * where the buffer started so we can 917 * compute the new header length. 918 */ 919 bcopy(sc->sc_buf, chdr, CHDR_LEN); 920 } 921 922 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 923 if (c & 0x80) 924 c = TYPE_COMPRESSED_TCP; 925 else if (c == TYPE_UNCOMPRESSED_TCP) 926 *sc->sc_buf &= 0x4f; /* XXX */ 927 /* 928 * We've got something that's not an IP packet. 929 * If compression is enabled, try to decompress it. 930 * Otherwise, if `auto-enable' compression is on and 931 * it's a reasonable packet, decompress it and then 932 * enable compression. Otherwise, drop it. 933 */ 934 if (sc->sc_if.if_flags & SC_COMPRESS) { 935 len = sl_uncompress_tcp(&sc->sc_buf, len, 936 (u_int)c, &sc->sc_comp); 937 if (len <= 0) 938 goto error; 939 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 940 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 941 len = sl_uncompress_tcp(&sc->sc_buf, len, 942 (u_int)c, &sc->sc_comp); 943 if (len <= 0) 944 goto error; 945 sc->sc_if.if_flags |= SC_COMPRESS; 946 } else 947 goto error; 948 } 949 if (sc->sc_if.if_bpf) { 950 /* 951 * Put the SLIP pseudo-"link header" in place. 952 * We couldn't do this any earlier since 953 * decompression probably moved the buffer 954 * pointer. Then, invoke BPF. 955 */ 956 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 957 958 hp[SLX_DIR] = SLIPDIR_IN; 959 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 960 BPF_TAP(&sc->sc_if, hp, len + SLIP_HDRLEN); 961 } 962 m = sl_btom(sc, len); 963 if (m == NULL) 964 goto error; 965 966 sc->sc_if.if_ipackets++; 967 968 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 969 m_freem(m); 970 goto newpack; 971 } 972 973 if (! IF_HANDOFF(&ipintrq, m, NULL)) { 974 sc->sc_if.if_ierrors++; 975 sc->sc_if.if_iqdrops++; 976 } else { 977 schednetisr(NETISR_IP); 978 } 979 goto newpack; 980 } 981 if (sc->sc_mp < sc->sc_ep) { 982 *sc->sc_mp++ = c; 983 sc->sc_escape = 0; 984 return 0; 985 } 986 987 /* can't put lower; would miss an extra frame */ 988 sc->sc_flags |= SC_ERROR; 989 990 error: 991 sc->sc_if.if_ierrors++; 992 newpack: 993 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 994 sc->sc_escape = 0; 995 return 0; 996 } 997 998 /* 999 * Process an ioctl request. 1000 */ 1001 static int 1002 slioctl(ifp, cmd, data) 1003 register struct ifnet *ifp; 1004 u_long cmd; 1005 caddr_t data; 1006 { 1007 register struct ifaddr *ifa = (struct ifaddr *)data; 1008 register struct ifreq *ifr = (struct ifreq *)data; 1009 register int s, error = 0; 1010 struct sl_softc *sc = ifp->if_softc; 1011 1012 s = splimp(); 1013 1014 switch (cmd) { 1015 1016 case SIOCSIFFLAGS: 1017 /* 1018 * if.c will set the interface up even if we 1019 * don't want it to. 1020 */ 1021 if (sc->sc_ttyp == NULL) { 1022 ifp->if_flags &= ~IFF_UP; 1023 } 1024 break; 1025 case SIOCSIFADDR: 1026 /* 1027 * This is "historical" - set the interface up when 1028 * setting the address. 1029 */ 1030 if (ifa->ifa_addr->sa_family == AF_INET) { 1031 if (sc->sc_ttyp != NULL) 1032 ifp->if_flags |= IFF_UP; 1033 } else { 1034 error = EAFNOSUPPORT; 1035 } 1036 break; 1037 1038 case SIOCSIFDSTADDR: 1039 if (ifa->ifa_addr->sa_family != AF_INET) 1040 error = EAFNOSUPPORT; 1041 break; 1042 1043 case SIOCADDMULTI: 1044 case SIOCDELMULTI: 1045 break; 1046 1047 case SIOCSIFMTU: 1048 /* 1049 * Set the interface MTU. 1050 */ 1051 if (ifr->ifr_mtu > SLTMAX) 1052 error = EINVAL; 1053 else { 1054 struct tty *tp; 1055 1056 ifp->if_mtu = ifr->ifr_mtu; 1057 tp = sc->sc_ttyp; 1058 if (tp != NULL) 1059 clist_alloc_cblocks(&tp->t_outq, 1060 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1061 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1062 } 1063 break; 1064 1065 default: 1066 error = EINVAL; 1067 } 1068 splx(s); 1069 return (error); 1070 } 1071 1072 static void 1073 sl_keepalive(chan) 1074 void *chan; 1075 { 1076 struct sl_softc *sc = chan; 1077 1078 if (sc->sc_keepalive) { 1079 if (sc->sc_flags & SC_KEEPALIVE) { 1080 if (sc->sc_ttyp->t_pgrp != NULL) { 1081 PGRP_LOCK(sc->sc_ttyp->t_pgrp); 1082 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1083 PGRP_UNLOCK(sc->sc_ttyp->t_pgrp); 1084 } 1085 } else 1086 sc->sc_flags |= SC_KEEPALIVE; 1087 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1088 } else { 1089 sc->sc_flags &= ~SC_KEEPALIVE; 1090 } 1091 } 1092 1093 static void 1094 sl_outfill(chan) 1095 void *chan; 1096 { 1097 struct sl_softc *sc = chan; 1098 register struct tty *tp = sc->sc_ttyp; 1099 int s; 1100 1101 if (sc->sc_outfill && tp != NULL) { 1102 if (sc->sc_flags & SC_OUTWAIT) { 1103 s = splimp (); 1104 ++sc->sc_if.if_obytes; 1105 (void) putc(FRAME_END, &tp->t_outq); 1106 (*tp->t_oproc)(tp); 1107 splx (s); 1108 } else 1109 sc->sc_flags |= SC_OUTWAIT; 1110 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1111 } else { 1112 sc->sc_flags &= ~SC_OUTWAIT; 1113 } 1114 }
Cache object: 26ef7470568c2c078e5a5efc1780d2e4
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