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/5.1/sys/net/if_sl.c 111888 2003-03-04 23:19:55Z jlemon $ 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/socket.h> 77 #include <sys/sockio.h> 78 #include <sys/fcntl.h> 79 #include <sys/signalvar.h> 80 #include <sys/tty.h> 81 #include <sys/clist.h> 82 #include <sys/kernel.h> 83 #include <sys/conf.h> 84 #include <sys/module.h> 85 #include <sys/proc.h> 86 87 #include <net/if.h> 88 #include <net/if_types.h> 89 #include <net/netisr.h> 90 91 #if INET 92 #include <netinet/in.h> 93 #include <netinet/in_systm.h> 94 #include <netinet/in_var.h> 95 #include <netinet/ip.h> 96 #else 97 #error "Huh? Slip without inet?" 98 #endif 99 100 #include <net/slcompress.h> 101 #include <net/if_slvar.h> 102 #include <net/slip.h> 103 104 #include <net/bpf.h> 105 106 static MALLOC_DEFINE(M_SL, "sl", "SLIP Interface"); 107 108 /* 109 * SLRMAX is a hard limit on input packet size. To simplify the code 110 * and improve performance, we require that packets fit in an mbuf 111 * cluster, and if we get a compressed packet, there's enough extra 112 * room to expand the header into a max length tcp/ip header (128 113 * bytes). So, SLRMAX can be at most 114 * MCLBYTES - 128 115 * 116 * SLMTU is the default transmit MTU. The transmit MTU should be kept 117 * small enough so that interactive use doesn't suffer, but large 118 * enough to provide good performance. 552 is a good choice for SLMTU 119 * because it is high enough to not fragment TCP packets being routed 120 * through this host. Packet fragmentation is bad with SLIP because 121 * fragment headers aren't compressed. The previous assumptions about 122 * the best MTU value don't really hold when using modern modems with 123 * BTLZ data compression because the modem buffers play a much larger 124 * role in interactive performance than the MTU. The MTU can be changed 125 * at any time to suit the specific environment with ifconfig(8), and 126 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 127 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 128 * handles this better). 129 * 130 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 131 * of us (i.e., in clists waiting to be picked up by the tty output 132 * interrupt). If we queue a lot of data downstream, it's immune to 133 * our t.o.s. queuing. 134 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 135 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 136 * wait is dependent on the ftp window size but that's typically 137 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 138 * the cost (in idle time on the wire) of the tty driver running 139 * off the end of its clists & having to call back slstart for a 140 * new packet. For a tty interface with any buffering at all, this 141 * cost will be zero. Even with a totally brain dead interface (like 142 * the one on a typical workstation), the cost will be <= 1 character 143 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 144 * at most 1% while maintaining good interactive response. 145 */ 146 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 147 #define SLRMAX (MCLBYTES - BUFOFFSET) 148 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 149 #ifndef SLMTU 150 #define SLMTU 552 /* default MTU */ 151 #endif 152 #define SLTMAX 1500 /* maximum MTU */ 153 #define SLIP_HIWAT roundup(50,CBSIZE) 154 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 155 156 /* 157 * SLIP ABORT ESCAPE MECHANISM: 158 * (inspired by HAYES modem escape arrangement) 159 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 160 * within window time signals a "soft" exit from slip mode by remote end 161 * if the IFF_DEBUG flag is on. 162 */ 163 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 164 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 165 #define ABT_COUNT 3 /* count of escapes for abort */ 166 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 167 168 static LIST_HEAD(sl_list, sl_softc) sl_list; 169 170 #define FRAME_END 0xc0 /* Frame End */ 171 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 172 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 173 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 174 175 static int slisstatic(int); 176 static void slmarkstatic(int); 177 static struct sl_softc *slcreate(void); 178 static void sldestroy(struct sl_softc *sc); 179 static struct mbuf *sl_btom(struct sl_softc *, int); 180 static timeout_t sl_keepalive; 181 static timeout_t sl_outfill; 182 static l_close_t slclose; 183 static l_rint_t slinput; 184 static l_ioctl_t sltioctl; 185 static int slioctl(struct ifnet *, u_long, caddr_t); 186 static int slopen(dev_t, struct tty *); 187 static int sloutput(struct ifnet *, 188 struct mbuf *, struct sockaddr *, struct rtentry *); 189 static int slstart(struct tty *); 190 191 static struct linesw slipdisc = { 192 slopen, slclose, l_noread, l_nowrite, 193 sltioctl, slinput, slstart, ttymodem, 194 FRAME_END 195 }; 196 197 /* 198 * Called from boot code to establish sl interfaces. 199 */ 200 static int 201 sl_modevent(module_t mod, int type, void *data) 202 { 203 switch (type) { 204 case MOD_LOAD: 205 linesw[SLIPDISC] = slipdisc; 206 LIST_INIT(&sl_list); 207 break; 208 case MOD_UNLOAD: 209 printf("if_sl module unload - not possible for this module type\n"); 210 return EINVAL; 211 } 212 return 0; 213 } 214 215 static moduledata_t sl_mod = { 216 "if_sl", 217 sl_modevent, 218 0 219 }; 220 221 DECLARE_MODULE(if_sl, sl_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 222 223 static int *st_unit_list; 224 static size_t st_unit_max = 0; 225 226 static int 227 slisstatic(unit) 228 int unit; 229 { 230 size_t i; 231 232 for (i = 0; i < st_unit_max; i++) 233 if (st_unit_list[i] == unit) 234 return 1; 235 return 0; 236 } 237 238 static void 239 slmarkstatic(unit) 240 int unit; 241 { 242 int *t; 243 244 if (slisstatic(unit)) 245 return; 246 247 MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT); 248 if (t == NULL) 249 return; 250 251 if (st_unit_list) { 252 bcopy(st_unit_list, t, sizeof(int) * st_unit_max); 253 free(st_unit_list, M_SL); 254 } 255 st_unit_list = t; 256 st_unit_list[st_unit_max] = unit; 257 st_unit_max++; 258 } 259 260 static struct sl_softc * 261 slcreate() 262 { 263 struct sl_softc *sc, *nc; 264 int unit; 265 struct mbuf *m; 266 267 MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO); 268 269 m = m_gethdr(M_TRYWAIT, MT_DATA); 270 if (m != NULL) { 271 MCLGET(m, M_TRYWAIT); 272 if ((m->m_flags & M_EXT) == 0) { 273 m_free(m); 274 m = NULL; 275 } 276 } 277 278 if (m == NULL) { 279 printf("sl: can't allocate buffer\n"); 280 free(sc, M_SL); 281 return (NULL); 282 } 283 284 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 285 sc->sc_mbuf = m; 286 sc->sc_buf = sc->sc_ep - SLRMAX; 287 sc->sc_mp = sc->sc_buf; 288 sl_compress_init(&sc->sc_comp, -1); 289 290 sc->sc_if.if_softc = sc; 291 sc->sc_if.if_name = "sl"; 292 sc->sc_if.if_mtu = SLMTU; 293 sc->sc_if.if_flags = 294 #ifdef SLIP_IFF_OPTS 295 SLIP_IFF_OPTS; 296 #else 297 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 298 #endif 299 sc->sc_if.if_type = IFT_SLIP; 300 sc->sc_if.if_ioctl = slioctl; 301 sc->sc_if.if_output = sloutput; 302 sc->sc_if.if_snd.ifq_maxlen = 50; 303 sc->sc_fastq.ifq_maxlen = 32; 304 sc->sc_if.if_linkmib = sc; 305 sc->sc_if.if_linkmiblen = sizeof *sc; 306 mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF); 307 308 /* 309 * Find a suitable unit number. 310 */ 311 for (unit=0; ; unit++) { 312 if (slisstatic(unit)) 313 continue; 314 LIST_FOREACH(nc, &sl_list, sl_next) { 315 if (nc->sc_if.if_unit == unit) 316 continue; 317 } 318 break; 319 } 320 sc->sc_if.if_unit = unit; 321 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 322 323 if_attach(&sc->sc_if); 324 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 325 326 return sc; 327 } 328 329 330 /* 331 * Line specific open routine. 332 * Attach the given tty to the first available sl unit. 333 */ 334 /* ARGSUSED */ 335 static int 336 slopen(dev, tp) 337 dev_t dev; 338 register struct tty *tp; 339 { 340 register struct sl_softc *sc; 341 int s, error; 342 343 error = suser(curthread); 344 if (error) 345 return (error); 346 347 if (tp->t_line == SLIPDISC) 348 return (0); 349 350 if ((sc = slcreate()) == NULL) 351 return (ENOBUFS); 352 353 tp->t_sc = (caddr_t)sc; 354 sc->sc_ttyp = tp; 355 sc->sc_if.if_baudrate = tp->t_ospeed; 356 ttyflush(tp, FREAD | FWRITE); 357 tp->t_line = SLIPDISC; 358 359 /* 360 * We don't use t_canq or t_rawq, so reduce their 361 * cblock resources to 0. Reserve enough cblocks 362 * for t_outq to guarantee that we can fit a full 363 * packet if the SLIP_HIWAT check allows slstart() 364 * to loop. Use the same value for the cblock 365 * limit since the reserved blocks should always 366 * be enough. Reserving cblocks probably makes 367 * the CLISTRESERVE check unnecessary and wasteful. 368 */ 369 clist_alloc_cblocks(&tp->t_canq, 0, 0); 370 clist_alloc_cblocks(&tp->t_outq, 371 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 372 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 373 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 374 375 s = splnet(); 376 if_up(&sc->sc_if); 377 splx(s); 378 return (0); 379 } 380 381 static void 382 sldestroy(struct sl_softc *sc) 383 { 384 bpfdetach(&sc->sc_if); 385 if_detach(&sc->sc_if); 386 LIST_REMOVE(sc, sl_next); 387 m_free(sc->sc_mbuf); 388 mtx_destroy(&sc->sc_fastq.ifq_mtx); 389 if (sc->bpfbuf) 390 free(sc->bpfbuf, M_SL); 391 free(sc, M_SL); 392 } 393 394 /* 395 * Line specific close routine. 396 * Detach the tty from the sl unit. 397 */ 398 static int 399 slclose(tp,flag) 400 struct tty *tp; 401 int flag; 402 { 403 register struct sl_softc *sc; 404 int s; 405 406 ttyflush(tp, FREAD | FWRITE); 407 /* 408 * XXX the placement of the following spl is misleading. tty 409 * interrupts must be blocked across line discipline switches 410 * and throughout closes to avoid races. 411 */ 412 s = splimp(); /* actually, max(spltty, splnet) */ 413 clist_free_cblocks(&tp->t_outq); 414 tp->t_line = 0; 415 sc = (struct sl_softc *)tp->t_sc; 416 if (sc != NULL) { 417 if (sc->sc_outfill) { 418 sc->sc_outfill = 0; 419 untimeout(sl_outfill, sc, sc->sc_ofhandle); 420 } 421 if (sc->sc_keepalive) { 422 sc->sc_keepalive = 0; 423 untimeout(sl_keepalive, sc, sc->sc_kahandle); 424 } 425 if_down(&sc->sc_if); 426 sc->sc_ttyp = NULL; 427 tp->t_sc = NULL; 428 sldestroy(sc); 429 } 430 splx(s); 431 return 0; 432 } 433 434 /* 435 * Line specific (tty) ioctl routine. 436 * Provide a way to get the sl unit number. 437 */ 438 /* ARGSUSED */ 439 static int 440 sltioctl(tp, cmd, data, flag, td) 441 struct tty *tp; 442 u_long cmd; 443 caddr_t data; 444 int flag; 445 struct thread *td; 446 { 447 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc; 448 int s, unit, wasup; 449 450 s = splimp(); 451 switch (cmd) { 452 case SLIOCGUNIT: 453 *(int *)data = sc->sc_if.if_unit; 454 break; 455 456 case SLIOCSUNIT: 457 unit = *(u_int *)data; 458 if (unit < 0) { 459 splx(s); 460 return (ENXIO); 461 } 462 if (sc->sc_if.if_unit != unit) { 463 LIST_FOREACH(nc, &sl_list, sl_next) { 464 if (nc->sc_if.if_unit == *(u_int *)data) { 465 splx(s); 466 return (ENXIO); 467 } 468 } 469 470 wasup = sc->sc_if.if_flags & IFF_UP; 471 bpfdetach(&sc->sc_if); 472 if_detach(&sc->sc_if); 473 LIST_REMOVE(sc, sl_next); 474 sc->sc_if.if_unit = unit; 475 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 476 if_attach(&sc->sc_if); 477 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 478 if (wasup) 479 if_up(&sc->sc_if); 480 else 481 if_down(&sc->sc_if); 482 clist_alloc_cblocks(&tp->t_outq, 483 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 484 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 485 } 486 slmarkstatic(unit); 487 break; 488 489 case SLIOCSKEEPAL: 490 sc->sc_keepalive = *(u_int *)data * hz; 491 if (sc->sc_keepalive) { 492 sc->sc_flags |= SC_KEEPALIVE; 493 sc->sc_kahandle = timeout(sl_keepalive, sc, 494 sc->sc_keepalive); 495 } else { 496 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 497 untimeout(sl_keepalive, sc, sc->sc_kahandle); 498 sc->sc_flags &= ~SC_KEEPALIVE; 499 } 500 } 501 break; 502 503 case SLIOCGKEEPAL: 504 *(int *)data = sc->sc_keepalive / hz; 505 break; 506 507 case SLIOCSOUTFILL: 508 sc->sc_outfill = *(u_int *)data * hz; 509 if (sc->sc_outfill) { 510 sc->sc_flags |= SC_OUTWAIT; 511 sc->sc_ofhandle = timeout(sl_outfill, sc, 512 sc->sc_outfill); 513 } else { 514 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 515 untimeout(sl_outfill, sc, sc->sc_ofhandle); 516 sc->sc_flags &= ~SC_OUTWAIT; 517 } 518 } 519 break; 520 521 case SLIOCGOUTFILL: 522 *(int *)data = sc->sc_outfill / hz; 523 break; 524 525 default: 526 splx(s); 527 return (ENOIOCTL); 528 } 529 splx(s); 530 return (0); 531 } 532 533 /* 534 * Queue a packet. Start transmission if not active. 535 * Compression happens in slstart; if we do it here, IP TOS 536 * will cause us to not compress "background" packets, because 537 * ordering gets trashed. It can be done for all packets in slstart. 538 */ 539 static int 540 sloutput(ifp, m, dst, rtp) 541 struct ifnet *ifp; 542 register struct mbuf *m; 543 struct sockaddr *dst; 544 struct rtentry *rtp; 545 { 546 register struct sl_softc *sc = ifp->if_softc; 547 register struct ip *ip; 548 register struct ifqueue *ifq; 549 int s; 550 551 /* 552 * `Cannot happen' (see slioctl). Someday we will extend 553 * the line protocol to support other address families. 554 */ 555 if (dst->sa_family != AF_INET) { 556 if_printf(ifp, "af%d not supported\n", dst->sa_family); 557 m_freem(m); 558 sc->sc_if.if_noproto++; 559 return (EAFNOSUPPORT); 560 } 561 562 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 563 m_freem(m); 564 return (ENETDOWN); 565 } 566 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 567 m_freem(m); 568 return (EHOSTUNREACH); 569 } 570 ifq = &sc->sc_if.if_snd; 571 ip = mtod(m, struct ip *); 572 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 573 m_freem(m); 574 return (ENETRESET); /* XXX ? */ 575 } 576 if (ip->ip_tos & IPTOS_LOWDELAY) 577 ifq = &sc->sc_fastq; 578 if (! IF_HANDOFF(ifq, m, NULL)) { 579 sc->sc_if.if_oerrors++; 580 return (ENOBUFS); 581 } 582 s = splimp(); 583 if (sc->sc_ttyp->t_outq.c_cc == 0) 584 slstart(sc->sc_ttyp); 585 splx(s); 586 return (0); 587 } 588 589 /* 590 * Start output on interface. Get another datagram 591 * to send from the interface queue and map it to 592 * the interface before starting output. 593 */ 594 static int 595 slstart(tp) 596 register struct tty *tp; 597 { 598 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 599 register struct mbuf *m; 600 register u_char *cp; 601 register struct ip *ip; 602 int s; 603 register int len = 0; 604 605 for (;;) { 606 /* 607 * Call output process whether or not there is more in the 608 * output queue. We are being called in lieu of ttstart 609 * and must do what it would. 610 */ 611 (*tp->t_oproc)(tp); 612 613 if (tp->t_outq.c_cc != 0) { 614 if (sc != NULL) 615 sc->sc_flags &= ~SC_OUTWAIT; 616 if (tp->t_outq.c_cc > SLIP_HIWAT) 617 return 0; 618 } 619 620 /* 621 * This happens briefly when the line shuts down. 622 */ 623 if (sc == NULL) 624 return 0; 625 626 /* 627 * Get a packet and send it to the interface. 628 */ 629 s = splimp(); 630 IF_DEQUEUE(&sc->sc_fastq, m); 631 if (m) 632 sc->sc_if.if_omcasts++; /* XXX */ 633 else 634 IF_DEQUEUE(&sc->sc_if.if_snd, m); 635 splx(s); 636 if (m == NULL) 637 return 0; 638 639 /* 640 * We do the header compression here rather than in sloutput 641 * because the packets will be out of order if we are using TOS 642 * queueing, and the connection id compression will get 643 * munged when this happens. 644 */ 645 if (sc->sc_if.if_bpf) { 646 /* 647 * We need to save the TCP/IP header before it's 648 * compressed. To avoid complicated code, we just 649 * copy the entire packet into a stack buffer (since 650 * this is a serial line, packets should be short 651 * and/or the copy should be negligible cost compared 652 * to the packet transmission time). 653 */ 654 register struct mbuf *m1 = m; 655 register u_char *cp; 656 657 if (sc->bpfbuf == NULL) 658 MALLOC(sc->bpfbuf, u_char *, 659 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT); 660 661 if (sc->bpfbuf) { 662 cp = sc->bpfbuf + SLIP_HDRLEN; 663 len = 0; 664 do { 665 register int mlen = m1->m_len; 666 667 bcopy(mtod(m1, caddr_t), cp, mlen); 668 cp += mlen; 669 len += mlen; 670 } while ((m1 = m1->m_next) != NULL); 671 } 672 } 673 ip = mtod(m, struct ip *); 674 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 675 if (sc->sc_if.if_flags & SC_COMPRESS) 676 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 677 &sc->sc_comp, 1); 678 } 679 if (sc->sc_if.if_bpf && sc->bpfbuf) { 680 /* 681 * Put the SLIP pseudo-"link header" in place. The 682 * compressed header is now at the beginning of the 683 * mbuf. 684 */ 685 sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT; 686 bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN); 687 BPF_TAP(&sc->sc_if, sc->bpfbuf, len + SLIP_HDRLEN); 688 } 689 690 /* 691 * If system is getting low on clists, just flush our 692 * output queue (if the stuff was important, it'll get 693 * retransmitted). Note that SLTMAX is used instead of 694 * the current if_mtu setting because connections that 695 * have already been established still use the original 696 * (possibly larger) mss. 697 */ 698 if (cfreecount < CLISTRESERVE + SLTMAX) { 699 m_freem(m); 700 sc->sc_if.if_collisions++; 701 continue; 702 } 703 704 sc->sc_flags &= ~SC_OUTWAIT; 705 /* 706 * The extra FRAME_END will start up a new packet, and thus 707 * will flush any accumulated garbage. We do this whenever 708 * the line may have been idle for some time. 709 */ 710 if (tp->t_outq.c_cc == 0) { 711 ++sc->sc_if.if_obytes; 712 (void) putc(FRAME_END, &tp->t_outq); 713 } 714 715 while (m) { 716 register u_char *ep; 717 718 cp = mtod(m, u_char *); ep = cp + m->m_len; 719 while (cp < ep) { 720 /* 721 * Find out how many bytes in the string we can 722 * handle without doing something special. 723 */ 724 register u_char *bp = cp; 725 726 while (cp < ep) { 727 switch (*cp++) { 728 case FRAME_ESCAPE: 729 case FRAME_END: 730 --cp; 731 goto out; 732 } 733 } 734 out: 735 if (cp > bp) { 736 /* 737 * Put n characters at once 738 * into the tty output queue. 739 */ 740 if (b_to_q((char *)bp, cp - bp, 741 &tp->t_outq)) 742 break; 743 sc->sc_if.if_obytes += cp - bp; 744 } 745 /* 746 * If there are characters left in the mbuf, 747 * the first one must be special.. 748 * Put it out in a different form. 749 */ 750 if (cp < ep) { 751 if (putc(FRAME_ESCAPE, &tp->t_outq)) 752 break; 753 if (putc(*cp++ == FRAME_ESCAPE ? 754 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 755 &tp->t_outq)) { 756 (void) unputc(&tp->t_outq); 757 break; 758 } 759 sc->sc_if.if_obytes += 2; 760 } 761 } 762 m = m_free(m); 763 } 764 765 if (putc(FRAME_END, &tp->t_outq)) { 766 /* 767 * Not enough room. Remove a char to make room 768 * and end the packet normally. 769 * If you get many collisions (more than one or two 770 * a day) you probably do not have enough clists 771 * and you should increase "nclist" in param.c. 772 */ 773 (void) unputc(&tp->t_outq); 774 (void) putc(FRAME_END, &tp->t_outq); 775 sc->sc_if.if_collisions++; 776 } else { 777 ++sc->sc_if.if_obytes; 778 sc->sc_if.if_opackets++; 779 } 780 } 781 return 0; 782 } 783 784 /* 785 * Copy data buffer to mbuf chain; add ifnet pointer. 786 */ 787 static struct mbuf * 788 sl_btom(sc, len) 789 register struct sl_softc *sc; 790 register int len; 791 { 792 struct mbuf *m, *newm; 793 794 MGETHDR(m, M_DONTWAIT, MT_DATA); 795 if (m == NULL) 796 return (NULL); 797 798 /* 799 * If we have more than MHLEN bytes, it's cheaper to 800 * queue the cluster we just filled & allocate a new one 801 * for the input buffer. Otherwise, fill the mbuf we 802 * allocated above. Note that code in the input routine 803 * guarantees that packet will fit in a cluster. 804 */ 805 if (len >= MHLEN) { 806 MCLGET(m, M_DONTWAIT); 807 if ((m->m_flags & M_EXT) == 0) { 808 /* 809 * we couldn't get a cluster - if memory's this 810 * low, it's time to start dropping packets. 811 */ 812 (void) m_free(m); 813 return (NULL); 814 } 815 /* Swap the new and old clusters */ 816 newm = m; 817 m = sc->sc_mbuf; 818 sc->sc_mbuf = newm; 819 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE; 820 821 m->m_data = (caddr_t)sc->sc_buf; 822 } else 823 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 824 825 m->m_len = len; 826 m->m_pkthdr.len = len; 827 m->m_pkthdr.rcvif = &sc->sc_if; 828 return (m); 829 } 830 831 /* 832 * tty interface receiver interrupt. 833 */ 834 static int 835 slinput(c, tp) 836 register int c; 837 register struct tty *tp; 838 { 839 register struct sl_softc *sc; 840 register struct mbuf *m; 841 register int len; 842 u_char chdr[CHDR_LEN]; 843 844 tk_nin++; 845 sc = (struct sl_softc *)tp->t_sc; 846 if (sc == NULL) 847 return 0; 848 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 849 sc->sc_flags |= SC_ERROR; 850 return 0; 851 } 852 c &= TTY_CHARMASK; 853 854 ++sc->sc_if.if_ibytes; 855 856 if (sc->sc_if.if_flags & IFF_DEBUG) { 857 if (c == ABT_ESC) { 858 /* 859 * If we have a previous abort, see whether 860 * this one is within the time limit. 861 */ 862 if (sc->sc_abortcount && 863 time_second >= sc->sc_starttime + ABT_WINDOW) 864 sc->sc_abortcount = 0; 865 /* 866 * If we see an abort after "idle" time, count it; 867 * record when the first abort escape arrived. 868 */ 869 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 870 if (++sc->sc_abortcount == 1) 871 sc->sc_starttime = time_second; 872 if (sc->sc_abortcount >= ABT_COUNT) { 873 slclose(tp,0); 874 return 0; 875 } 876 } 877 } else 878 sc->sc_abortcount = 0; 879 sc->sc_lasttime = time_second; 880 } 881 882 switch (c) { 883 884 case TRANS_FRAME_ESCAPE: 885 if (sc->sc_escape) 886 c = FRAME_ESCAPE; 887 break; 888 889 case TRANS_FRAME_END: 890 if (sc->sc_escape) 891 c = FRAME_END; 892 break; 893 894 case FRAME_ESCAPE: 895 sc->sc_escape = 1; 896 return 0; 897 898 case FRAME_END: 899 sc->sc_flags &= ~SC_KEEPALIVE; 900 if(sc->sc_flags & SC_ERROR) { 901 sc->sc_flags &= ~SC_ERROR; 902 goto newpack; 903 } 904 len = sc->sc_mp - sc->sc_buf; 905 if (len < 3) 906 /* less than min length packet - ignore */ 907 goto newpack; 908 909 if (sc->sc_if.if_bpf) { 910 /* 911 * Save the compressed header, so we 912 * can tack it on later. Note that we 913 * will end up copying garbage in some 914 * cases but this is okay. We remember 915 * where the buffer started so we can 916 * compute the new header length. 917 */ 918 bcopy(sc->sc_buf, chdr, CHDR_LEN); 919 } 920 921 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 922 if (c & 0x80) 923 c = TYPE_COMPRESSED_TCP; 924 else if (c == TYPE_UNCOMPRESSED_TCP) 925 *sc->sc_buf &= 0x4f; /* XXX */ 926 /* 927 * We've got something that's not an IP packet. 928 * If compression is enabled, try to decompress it. 929 * Otherwise, if `auto-enable' compression is on and 930 * it's a reasonable packet, decompress it and then 931 * enable compression. Otherwise, drop it. 932 */ 933 if (sc->sc_if.if_flags & SC_COMPRESS) { 934 len = sl_uncompress_tcp(&sc->sc_buf, len, 935 (u_int)c, &sc->sc_comp); 936 if (len <= 0) 937 goto error; 938 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 939 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 940 len = sl_uncompress_tcp(&sc->sc_buf, len, 941 (u_int)c, &sc->sc_comp); 942 if (len <= 0) 943 goto error; 944 sc->sc_if.if_flags |= SC_COMPRESS; 945 } else 946 goto error; 947 } 948 if (sc->sc_if.if_bpf) { 949 /* 950 * Put the SLIP pseudo-"link header" in place. 951 * We couldn't do this any earlier since 952 * decompression probably moved the buffer 953 * pointer. Then, invoke BPF. 954 */ 955 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 956 957 hp[SLX_DIR] = SLIPDIR_IN; 958 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 959 BPF_TAP(&sc->sc_if, hp, len + SLIP_HDRLEN); 960 } 961 m = sl_btom(sc, len); 962 if (m == NULL) 963 goto error; 964 965 sc->sc_if.if_ipackets++; 966 967 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 968 m_freem(m); 969 goto newpack; 970 } 971 if (! netisr_queue(NETISR_IP, m)) { 972 sc->sc_if.if_ierrors++; 973 sc->sc_if.if_iqdrops++; 974 } 975 goto newpack; 976 } 977 if (sc->sc_mp < sc->sc_ep) { 978 *sc->sc_mp++ = c; 979 sc->sc_escape = 0; 980 return 0; 981 } 982 983 /* can't put lower; would miss an extra frame */ 984 sc->sc_flags |= SC_ERROR; 985 986 error: 987 sc->sc_if.if_ierrors++; 988 newpack: 989 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 990 sc->sc_escape = 0; 991 return 0; 992 } 993 994 /* 995 * Process an ioctl request. 996 */ 997 static int 998 slioctl(ifp, cmd, data) 999 register struct ifnet *ifp; 1000 u_long cmd; 1001 caddr_t data; 1002 { 1003 register struct ifaddr *ifa = (struct ifaddr *)data; 1004 register struct ifreq *ifr = (struct ifreq *)data; 1005 register int s, error = 0; 1006 struct sl_softc *sc = ifp->if_softc; 1007 1008 s = splimp(); 1009 1010 switch (cmd) { 1011 1012 case SIOCSIFFLAGS: 1013 /* 1014 * if.c will set the interface up even if we 1015 * don't want it to. 1016 */ 1017 if (sc->sc_ttyp == NULL) { 1018 ifp->if_flags &= ~IFF_UP; 1019 } 1020 break; 1021 case SIOCSIFADDR: 1022 /* 1023 * This is "historical" - set the interface up when 1024 * setting the address. 1025 */ 1026 if (ifa->ifa_addr->sa_family == AF_INET) { 1027 if (sc->sc_ttyp != NULL) 1028 ifp->if_flags |= IFF_UP; 1029 } else { 1030 error = EAFNOSUPPORT; 1031 } 1032 break; 1033 1034 case SIOCSIFDSTADDR: 1035 if (ifa->ifa_addr->sa_family != AF_INET) 1036 error = EAFNOSUPPORT; 1037 break; 1038 1039 case SIOCADDMULTI: 1040 case SIOCDELMULTI: 1041 break; 1042 1043 case SIOCSIFMTU: 1044 /* 1045 * Set the interface MTU. 1046 */ 1047 if (ifr->ifr_mtu > SLTMAX) 1048 error = EINVAL; 1049 else { 1050 struct tty *tp; 1051 1052 ifp->if_mtu = ifr->ifr_mtu; 1053 tp = sc->sc_ttyp; 1054 if (tp != NULL) 1055 clist_alloc_cblocks(&tp->t_outq, 1056 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1057 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1058 } 1059 break; 1060 1061 default: 1062 error = EINVAL; 1063 } 1064 splx(s); 1065 return (error); 1066 } 1067 1068 static void 1069 sl_keepalive(chan) 1070 void *chan; 1071 { 1072 struct sl_softc *sc = chan; 1073 1074 if (sc->sc_keepalive) { 1075 if (sc->sc_flags & SC_KEEPALIVE) { 1076 if (sc->sc_ttyp->t_pgrp != NULL) { 1077 PGRP_LOCK(sc->sc_ttyp->t_pgrp); 1078 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1079 PGRP_UNLOCK(sc->sc_ttyp->t_pgrp); 1080 } 1081 } else 1082 sc->sc_flags |= SC_KEEPALIVE; 1083 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1084 } else { 1085 sc->sc_flags &= ~SC_KEEPALIVE; 1086 } 1087 } 1088 1089 static void 1090 sl_outfill(chan) 1091 void *chan; 1092 { 1093 struct sl_softc *sc = chan; 1094 register struct tty *tp = sc->sc_ttyp; 1095 int s; 1096 1097 if (sc->sc_outfill && tp != NULL) { 1098 if (sc->sc_flags & SC_OUTWAIT) { 1099 s = splimp (); 1100 ++sc->sc_if.if_obytes; 1101 (void) putc(FRAME_END, &tp->t_outq); 1102 (*tp->t_oproc)(tp); 1103 splx (s); 1104 } else 1105 sc->sc_flags |= SC_OUTWAIT; 1106 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1107 } else { 1108 sc->sc_flags &= ~SC_OUTWAIT; 1109 } 1110 }
Cache object: 92ca2d8c8b80ee6585411db9ce8207b8
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