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/5.2/sys/net/if_sl.c 121816 2003-10-31 18:32:15Z brooks $ 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_mtu = SLMTU; 292 sc->sc_if.if_flags = 293 #ifdef SLIP_IFF_OPTS 294 SLIP_IFF_OPTS; 295 #else 296 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 297 #endif 298 sc->sc_if.if_type = IFT_SLIP; 299 sc->sc_if.if_ioctl = slioctl; 300 sc->sc_if.if_output = sloutput; 301 sc->sc_if.if_snd.ifq_maxlen = 50; 302 sc->sc_fastq.ifq_maxlen = 32; 303 sc->sc_if.if_linkmib = sc; 304 sc->sc_if.if_linkmiblen = sizeof *sc; 305 mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF); 306 307 /* 308 * Find a suitable unit number. 309 */ 310 for (unit=0; ; unit++) { 311 if (slisstatic(unit)) 312 continue; 313 LIST_FOREACH(nc, &sl_list, sl_next) { 314 if (nc->sc_if.if_dunit == unit) 315 continue; 316 } 317 break; 318 } 319 if_initname(&sc->sc_if, "sl", unit); 320 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 321 322 if_attach(&sc->sc_if); 323 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 324 325 return sc; 326 } 327 328 329 /* 330 * Line specific open routine. 331 * Attach the given tty to the first available sl unit. 332 */ 333 /* ARGSUSED */ 334 static int 335 slopen(dev, tp) 336 dev_t dev; 337 register struct tty *tp; 338 { 339 register struct sl_softc *sc; 340 int s, error; 341 342 error = suser(curthread); 343 if (error) 344 return (error); 345 346 if (tp->t_line == SLIPDISC) 347 return (0); 348 349 if ((sc = slcreate()) == NULL) 350 return (ENOBUFS); 351 352 tp->t_sc = (caddr_t)sc; 353 sc->sc_ttyp = tp; 354 sc->sc_if.if_baudrate = tp->t_ospeed; 355 ttyflush(tp, FREAD | FWRITE); 356 tp->t_line = SLIPDISC; 357 358 /* 359 * We don't use t_canq or t_rawq, so reduce their 360 * cblock resources to 0. Reserve enough cblocks 361 * for t_outq to guarantee that we can fit a full 362 * packet if the SLIP_HIWAT check allows slstart() 363 * to loop. Use the same value for the cblock 364 * limit since the reserved blocks should always 365 * be enough. Reserving cblocks probably makes 366 * the CLISTRESERVE check unnecessary and wasteful. 367 */ 368 clist_alloc_cblocks(&tp->t_canq, 0, 0); 369 clist_alloc_cblocks(&tp->t_outq, 370 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 371 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 372 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 373 374 s = splnet(); 375 if_up(&sc->sc_if); 376 splx(s); 377 return (0); 378 } 379 380 static void 381 sldestroy(struct sl_softc *sc) 382 { 383 bpfdetach(&sc->sc_if); 384 if_detach(&sc->sc_if); 385 LIST_REMOVE(sc, sl_next); 386 m_free(sc->sc_mbuf); 387 mtx_destroy(&sc->sc_fastq.ifq_mtx); 388 if (sc->bpfbuf) 389 free(sc->bpfbuf, M_SL); 390 free(sc, M_SL); 391 } 392 393 /* 394 * Line specific close routine. 395 * Detach the tty from the sl unit. 396 */ 397 static int 398 slclose(tp,flag) 399 struct tty *tp; 400 int flag; 401 { 402 register struct sl_softc *sc; 403 int s; 404 405 ttyflush(tp, FREAD | FWRITE); 406 /* 407 * XXX the placement of the following spl is misleading. tty 408 * interrupts must be blocked across line discipline switches 409 * and throughout closes to avoid races. 410 */ 411 s = splimp(); /* actually, max(spltty, splnet) */ 412 clist_free_cblocks(&tp->t_outq); 413 tp->t_line = 0; 414 sc = (struct sl_softc *)tp->t_sc; 415 if (sc != NULL) { 416 if (sc->sc_outfill) { 417 sc->sc_outfill = 0; 418 untimeout(sl_outfill, sc, sc->sc_ofhandle); 419 } 420 if (sc->sc_keepalive) { 421 sc->sc_keepalive = 0; 422 untimeout(sl_keepalive, sc, sc->sc_kahandle); 423 } 424 if_down(&sc->sc_if); 425 sc->sc_ttyp = NULL; 426 tp->t_sc = NULL; 427 sldestroy(sc); 428 } 429 splx(s); 430 return 0; 431 } 432 433 /* 434 * Line specific (tty) ioctl routine. 435 * Provide a way to get the sl unit number. 436 */ 437 /* ARGSUSED */ 438 static int 439 sltioctl(tp, cmd, data, flag, td) 440 struct tty *tp; 441 u_long cmd; 442 caddr_t data; 443 int flag; 444 struct thread *td; 445 { 446 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc; 447 int s, unit, wasup; 448 449 s = splimp(); 450 switch (cmd) { 451 case SLIOCGUNIT: 452 *(int *)data = sc->sc_if.if_dunit; 453 break; 454 455 case SLIOCSUNIT: 456 unit = *(u_int *)data; 457 if (unit < 0) { 458 splx(s); 459 return (ENXIO); 460 } 461 if (sc->sc_if.if_dunit != unit) { 462 LIST_FOREACH(nc, &sl_list, sl_next) { 463 if (nc->sc_if.if_dunit == *(u_int *)data) { 464 splx(s); 465 return (ENXIO); 466 } 467 } 468 469 wasup = sc->sc_if.if_flags & IFF_UP; 470 bpfdetach(&sc->sc_if); 471 if_detach(&sc->sc_if); 472 LIST_REMOVE(sc, sl_next); 473 if_initname(&sc->sc_if, "sl", unit); 474 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 475 if_attach(&sc->sc_if); 476 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 477 if (wasup) 478 if_up(&sc->sc_if); 479 else 480 if_down(&sc->sc_if); 481 clist_alloc_cblocks(&tp->t_outq, 482 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 483 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 484 } 485 slmarkstatic(unit); 486 break; 487 488 case SLIOCSKEEPAL: 489 sc->sc_keepalive = *(u_int *)data * hz; 490 if (sc->sc_keepalive) { 491 sc->sc_flags |= SC_KEEPALIVE; 492 sc->sc_kahandle = timeout(sl_keepalive, sc, 493 sc->sc_keepalive); 494 } else { 495 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 496 untimeout(sl_keepalive, sc, sc->sc_kahandle); 497 sc->sc_flags &= ~SC_KEEPALIVE; 498 } 499 } 500 break; 501 502 case SLIOCGKEEPAL: 503 *(int *)data = sc->sc_keepalive / hz; 504 break; 505 506 case SLIOCSOUTFILL: 507 sc->sc_outfill = *(u_int *)data * hz; 508 if (sc->sc_outfill) { 509 sc->sc_flags |= SC_OUTWAIT; 510 sc->sc_ofhandle = timeout(sl_outfill, sc, 511 sc->sc_outfill); 512 } else { 513 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 514 untimeout(sl_outfill, sc, sc->sc_ofhandle); 515 sc->sc_flags &= ~SC_OUTWAIT; 516 } 517 } 518 break; 519 520 case SLIOCGOUTFILL: 521 *(int *)data = sc->sc_outfill / hz; 522 break; 523 524 default: 525 splx(s); 526 return (ENOIOCTL); 527 } 528 splx(s); 529 return (0); 530 } 531 532 /* 533 * Queue a packet. Start transmission if not active. 534 * Compression happens in slstart; if we do it here, IP TOS 535 * will cause us to not compress "background" packets, because 536 * ordering gets trashed. It can be done for all packets in slstart. 537 */ 538 static int 539 sloutput(ifp, m, dst, rtp) 540 struct ifnet *ifp; 541 register struct mbuf *m; 542 struct sockaddr *dst; 543 struct rtentry *rtp; 544 { 545 register struct sl_softc *sc = ifp->if_softc; 546 register struct ip *ip; 547 register struct ifqueue *ifq; 548 int s; 549 550 /* 551 * `Cannot happen' (see slioctl). Someday we will extend 552 * the line protocol to support other address families. 553 */ 554 if (dst->sa_family != AF_INET) { 555 if_printf(ifp, "af%d not supported\n", dst->sa_family); 556 m_freem(m); 557 sc->sc_if.if_noproto++; 558 return (EAFNOSUPPORT); 559 } 560 561 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 562 m_freem(m); 563 return (ENETDOWN); 564 } 565 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 566 m_freem(m); 567 return (EHOSTUNREACH); 568 } 569 ifq = &sc->sc_if.if_snd; 570 ip = mtod(m, struct ip *); 571 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 572 m_freem(m); 573 return (ENETRESET); /* XXX ? */ 574 } 575 if (ip->ip_tos & IPTOS_LOWDELAY) 576 ifq = &sc->sc_fastq; 577 if (! IF_HANDOFF(ifq, m, NULL)) { 578 sc->sc_if.if_oerrors++; 579 return (ENOBUFS); 580 } 581 s = splimp(); 582 if (sc->sc_ttyp->t_outq.c_cc == 0) 583 slstart(sc->sc_ttyp); 584 splx(s); 585 return (0); 586 } 587 588 /* 589 * Start output on interface. Get another datagram 590 * to send from the interface queue and map it to 591 * the interface before starting output. 592 */ 593 static int 594 slstart(tp) 595 register struct tty *tp; 596 { 597 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 598 register struct mbuf *m; 599 register u_char *cp; 600 register struct ip *ip; 601 int s; 602 register int len = 0; 603 604 for (;;) { 605 /* 606 * Call output process whether or not there is more in the 607 * output queue. We are being called in lieu of ttstart 608 * and must do what it would. 609 */ 610 (*tp->t_oproc)(tp); 611 612 if (tp->t_outq.c_cc != 0) { 613 if (sc != NULL) 614 sc->sc_flags &= ~SC_OUTWAIT; 615 if (tp->t_outq.c_cc > SLIP_HIWAT) 616 return 0; 617 } 618 619 /* 620 * This happens briefly when the line shuts down. 621 */ 622 if (sc == NULL) 623 return 0; 624 625 /* 626 * Get a packet and send it to the interface. 627 */ 628 s = splimp(); 629 IF_DEQUEUE(&sc->sc_fastq, m); 630 if (m) 631 sc->sc_if.if_omcasts++; /* XXX */ 632 else 633 IF_DEQUEUE(&sc->sc_if.if_snd, m); 634 splx(s); 635 if (m == NULL) 636 return 0; 637 638 /* 639 * We do the header compression here rather than in sloutput 640 * because the packets will be out of order if we are using TOS 641 * queueing, and the connection id compression will get 642 * munged when this happens. 643 */ 644 if (sc->sc_if.if_bpf) { 645 /* 646 * We need to save the TCP/IP header before it's 647 * compressed. To avoid complicated code, we just 648 * copy the entire packet into a stack buffer (since 649 * this is a serial line, packets should be short 650 * and/or the copy should be negligible cost compared 651 * to the packet transmission time). 652 */ 653 register struct mbuf *m1 = m; 654 register u_char *cp; 655 656 if (sc->bpfbuf == NULL) 657 MALLOC(sc->bpfbuf, u_char *, 658 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT); 659 660 if (sc->bpfbuf) { 661 cp = sc->bpfbuf + SLIP_HDRLEN; 662 len = 0; 663 do { 664 register int mlen = m1->m_len; 665 666 bcopy(mtod(m1, caddr_t), cp, mlen); 667 cp += mlen; 668 len += mlen; 669 } while ((m1 = m1->m_next) != NULL); 670 } 671 } 672 ip = mtod(m, struct ip *); 673 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 674 if (sc->sc_if.if_flags & SC_COMPRESS) 675 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 676 &sc->sc_comp, 1); 677 } 678 if (sc->sc_if.if_bpf && sc->bpfbuf) { 679 /* 680 * Put the SLIP pseudo-"link header" in place. The 681 * compressed header is now at the beginning of the 682 * mbuf. 683 */ 684 sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT; 685 bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN); 686 BPF_TAP(&sc->sc_if, sc->bpfbuf, len + SLIP_HDRLEN); 687 } 688 689 /* 690 * If system is getting low on clists, just flush our 691 * output queue (if the stuff was important, it'll get 692 * retransmitted). Note that SLTMAX is used instead of 693 * the current if_mtu setting because connections that 694 * have already been established still use the original 695 * (possibly larger) mss. 696 */ 697 if (cfreecount < CLISTRESERVE + SLTMAX) { 698 m_freem(m); 699 sc->sc_if.if_collisions++; 700 continue; 701 } 702 703 sc->sc_flags &= ~SC_OUTWAIT; 704 /* 705 * The extra FRAME_END will start up a new packet, and thus 706 * will flush any accumulated garbage. We do this whenever 707 * the line may have been idle for some time. 708 */ 709 if (tp->t_outq.c_cc == 0) { 710 ++sc->sc_if.if_obytes; 711 (void) putc(FRAME_END, &tp->t_outq); 712 } 713 714 while (m) { 715 register u_char *ep; 716 717 cp = mtod(m, u_char *); ep = cp + m->m_len; 718 while (cp < ep) { 719 /* 720 * Find out how many bytes in the string we can 721 * handle without doing something special. 722 */ 723 register u_char *bp = cp; 724 725 while (cp < ep) { 726 switch (*cp++) { 727 case FRAME_ESCAPE: 728 case FRAME_END: 729 --cp; 730 goto out; 731 } 732 } 733 out: 734 if (cp > bp) { 735 /* 736 * Put n characters at once 737 * into the tty output queue. 738 */ 739 if (b_to_q((char *)bp, cp - bp, 740 &tp->t_outq)) 741 break; 742 sc->sc_if.if_obytes += cp - bp; 743 } 744 /* 745 * If there are characters left in the mbuf, 746 * the first one must be special.. 747 * Put it out in a different form. 748 */ 749 if (cp < ep) { 750 if (putc(FRAME_ESCAPE, &tp->t_outq)) 751 break; 752 if (putc(*cp++ == FRAME_ESCAPE ? 753 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 754 &tp->t_outq)) { 755 (void) unputc(&tp->t_outq); 756 break; 757 } 758 sc->sc_if.if_obytes += 2; 759 } 760 } 761 m = m_free(m); 762 } 763 764 if (putc(FRAME_END, &tp->t_outq)) { 765 /* 766 * Not enough room. Remove a char to make room 767 * and end the packet normally. 768 * If you get many collisions (more than one or two 769 * a day) you probably do not have enough clists 770 * and you should increase "nclist" in param.c. 771 */ 772 (void) unputc(&tp->t_outq); 773 (void) putc(FRAME_END, &tp->t_outq); 774 sc->sc_if.if_collisions++; 775 } else { 776 ++sc->sc_if.if_obytes; 777 sc->sc_if.if_opackets++; 778 } 779 } 780 return 0; 781 } 782 783 /* 784 * Copy data buffer to mbuf chain; add ifnet pointer. 785 */ 786 static struct mbuf * 787 sl_btom(sc, len) 788 register struct sl_softc *sc; 789 register int len; 790 { 791 struct mbuf *m, *newm; 792 793 MGETHDR(m, M_DONTWAIT, MT_DATA); 794 if (m == NULL) 795 return (NULL); 796 797 /* 798 * If we have more than MHLEN bytes, it's cheaper to 799 * queue the cluster we just filled & allocate a new one 800 * for the input buffer. Otherwise, fill the mbuf we 801 * allocated above. Note that code in the input routine 802 * guarantees that packet will fit in a cluster. 803 */ 804 if (len >= MHLEN) { 805 MCLGET(m, M_DONTWAIT); 806 if ((m->m_flags & M_EXT) == 0) { 807 /* 808 * we couldn't get a cluster - if memory's this 809 * low, it's time to start dropping packets. 810 */ 811 (void) m_free(m); 812 return (NULL); 813 } 814 /* Swap the new and old clusters */ 815 newm = m; 816 m = sc->sc_mbuf; 817 sc->sc_mbuf = newm; 818 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE; 819 820 m->m_data = (caddr_t)sc->sc_buf; 821 } else 822 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 823 824 m->m_len = len; 825 m->m_pkthdr.len = len; 826 m->m_pkthdr.rcvif = &sc->sc_if; 827 return (m); 828 } 829 830 /* 831 * tty interface receiver interrupt. 832 */ 833 static int 834 slinput(c, tp) 835 register int c; 836 register struct tty *tp; 837 { 838 register struct sl_softc *sc; 839 register struct mbuf *m; 840 register int len; 841 u_char chdr[CHDR_LEN]; 842 843 tk_nin++; 844 sc = (struct sl_softc *)tp->t_sc; 845 if (sc == NULL) 846 return 0; 847 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 848 sc->sc_flags |= SC_ERROR; 849 return 0; 850 } 851 c &= TTY_CHARMASK; 852 853 ++sc->sc_if.if_ibytes; 854 855 if (sc->sc_if.if_flags & IFF_DEBUG) { 856 if (c == ABT_ESC) { 857 /* 858 * If we have a previous abort, see whether 859 * this one is within the time limit. 860 */ 861 if (sc->sc_abortcount && 862 time_second >= sc->sc_starttime + ABT_WINDOW) 863 sc->sc_abortcount = 0; 864 /* 865 * If we see an abort after "idle" time, count it; 866 * record when the first abort escape arrived. 867 */ 868 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 869 if (++sc->sc_abortcount == 1) 870 sc->sc_starttime = time_second; 871 if (sc->sc_abortcount >= ABT_COUNT) { 872 slclose(tp,0); 873 return 0; 874 } 875 } 876 } else 877 sc->sc_abortcount = 0; 878 sc->sc_lasttime = time_second; 879 } 880 881 switch (c) { 882 883 case TRANS_FRAME_ESCAPE: 884 if (sc->sc_escape) 885 c = FRAME_ESCAPE; 886 break; 887 888 case TRANS_FRAME_END: 889 if (sc->sc_escape) 890 c = FRAME_END; 891 break; 892 893 case FRAME_ESCAPE: 894 sc->sc_escape = 1; 895 return 0; 896 897 case FRAME_END: 898 sc->sc_flags &= ~SC_KEEPALIVE; 899 if(sc->sc_flags & SC_ERROR) { 900 sc->sc_flags &= ~SC_ERROR; 901 goto newpack; 902 } 903 len = sc->sc_mp - sc->sc_buf; 904 if (len < 3) 905 /* less than min length packet - ignore */ 906 goto newpack; 907 908 if (sc->sc_if.if_bpf) { 909 /* 910 * Save the compressed header, so we 911 * can tack it on later. Note that we 912 * will end up copying garbage in some 913 * cases but this is okay. We remember 914 * where the buffer started so we can 915 * compute the new header length. 916 */ 917 bcopy(sc->sc_buf, chdr, CHDR_LEN); 918 } 919 920 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 921 if (c & 0x80) 922 c = TYPE_COMPRESSED_TCP; 923 else if (c == TYPE_UNCOMPRESSED_TCP) 924 *sc->sc_buf &= 0x4f; /* XXX */ 925 /* 926 * We've got something that's not an IP packet. 927 * If compression is enabled, try to decompress it. 928 * Otherwise, if `auto-enable' compression is on and 929 * it's a reasonable packet, decompress it and then 930 * enable compression. Otherwise, drop it. 931 */ 932 if (sc->sc_if.if_flags & SC_COMPRESS) { 933 len = sl_uncompress_tcp(&sc->sc_buf, len, 934 (u_int)c, &sc->sc_comp); 935 if (len <= 0) 936 goto error; 937 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 938 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 939 len = sl_uncompress_tcp(&sc->sc_buf, len, 940 (u_int)c, &sc->sc_comp); 941 if (len <= 0) 942 goto error; 943 sc->sc_if.if_flags |= SC_COMPRESS; 944 } else 945 goto error; 946 } 947 if (sc->sc_if.if_bpf) { 948 /* 949 * Put the SLIP pseudo-"link header" in place. 950 * We couldn't do this any earlier since 951 * decompression probably moved the buffer 952 * pointer. Then, invoke BPF. 953 */ 954 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 955 956 hp[SLX_DIR] = SLIPDIR_IN; 957 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 958 BPF_TAP(&sc->sc_if, hp, len + SLIP_HDRLEN); 959 } 960 m = sl_btom(sc, len); 961 if (m == NULL) 962 goto error; 963 964 sc->sc_if.if_ipackets++; 965 966 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 967 m_freem(m); 968 goto newpack; 969 } 970 if (! netisr_queue(NETISR_IP, m)) { 971 sc->sc_if.if_ierrors++; 972 sc->sc_if.if_iqdrops++; 973 } 974 goto newpack; 975 } 976 if (sc->sc_mp < sc->sc_ep) { 977 *sc->sc_mp++ = c; 978 sc->sc_escape = 0; 979 return 0; 980 } 981 982 /* can't put lower; would miss an extra frame */ 983 sc->sc_flags |= SC_ERROR; 984 985 error: 986 sc->sc_if.if_ierrors++; 987 newpack: 988 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 989 sc->sc_escape = 0; 990 return 0; 991 } 992 993 /* 994 * Process an ioctl request. 995 */ 996 static int 997 slioctl(ifp, cmd, data) 998 register struct ifnet *ifp; 999 u_long cmd; 1000 caddr_t data; 1001 { 1002 register struct ifaddr *ifa = (struct ifaddr *)data; 1003 register struct ifreq *ifr = (struct ifreq *)data; 1004 register int s, error = 0; 1005 struct sl_softc *sc = ifp->if_softc; 1006 1007 s = splimp(); 1008 1009 switch (cmd) { 1010 1011 case SIOCSIFFLAGS: 1012 /* 1013 * if.c will set the interface up even if we 1014 * don't want it to. 1015 */ 1016 if (sc->sc_ttyp == NULL) { 1017 ifp->if_flags &= ~IFF_UP; 1018 } 1019 break; 1020 case SIOCSIFADDR: 1021 /* 1022 * This is "historical" - set the interface up when 1023 * setting the address. 1024 */ 1025 if (ifa->ifa_addr->sa_family == AF_INET) { 1026 if (sc->sc_ttyp != NULL) 1027 ifp->if_flags |= IFF_UP; 1028 } else { 1029 error = EAFNOSUPPORT; 1030 } 1031 break; 1032 1033 case SIOCSIFDSTADDR: 1034 if (ifa->ifa_addr->sa_family != AF_INET) 1035 error = EAFNOSUPPORT; 1036 break; 1037 1038 case SIOCADDMULTI: 1039 case SIOCDELMULTI: 1040 break; 1041 1042 case SIOCSIFMTU: 1043 /* 1044 * Set the interface MTU. 1045 */ 1046 if (ifr->ifr_mtu > SLTMAX) 1047 error = EINVAL; 1048 else { 1049 struct tty *tp; 1050 1051 ifp->if_mtu = ifr->ifr_mtu; 1052 tp = sc->sc_ttyp; 1053 if (tp != NULL) 1054 clist_alloc_cblocks(&tp->t_outq, 1055 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1056 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1057 } 1058 break; 1059 1060 default: 1061 error = EINVAL; 1062 } 1063 splx(s); 1064 return (error); 1065 } 1066 1067 static void 1068 sl_keepalive(chan) 1069 void *chan; 1070 { 1071 struct sl_softc *sc = chan; 1072 1073 if (sc->sc_keepalive) { 1074 if (sc->sc_flags & SC_KEEPALIVE) { 1075 if (sc->sc_ttyp->t_pgrp != NULL) { 1076 PGRP_LOCK(sc->sc_ttyp->t_pgrp); 1077 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1078 PGRP_UNLOCK(sc->sc_ttyp->t_pgrp); 1079 } 1080 } else 1081 sc->sc_flags |= SC_KEEPALIVE; 1082 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1083 } else { 1084 sc->sc_flags &= ~SC_KEEPALIVE; 1085 } 1086 } 1087 1088 static void 1089 sl_outfill(chan) 1090 void *chan; 1091 { 1092 struct sl_softc *sc = chan; 1093 register struct tty *tp = sc->sc_ttyp; 1094 int s; 1095 1096 if (sc->sc_outfill && tp != NULL) { 1097 if (sc->sc_flags & SC_OUTWAIT) { 1098 s = splimp (); 1099 ++sc->sc_if.if_obytes; 1100 (void) putc(FRAME_END, &tp->t_outq); 1101 (*tp->t_oproc)(tp); 1102 splx (s); 1103 } else 1104 sc->sc_flags |= SC_OUTWAIT; 1105 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1106 } else { 1107 sc->sc_flags &= ~SC_OUTWAIT; 1108 } 1109 }
Cache object: a0ecdccd9568a60003eecbec2f8735e1
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