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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)if_sl.c 8.6 (Berkeley) 2/1/94 30 * $FreeBSD: releng/6.4/sys/net/if_sl.c 166110 2007-01-19 23:01:34Z jhb $ 31 */ 32 33 /* 34 * Serial Line interface 35 * 36 * Rick Adams 37 * Center for Seismic Studies 38 * 1300 N 17th Street, Suite 1450 39 * Arlington, Virginia 22209 40 * (703)276-7900 41 * rick@seismo.ARPA 42 * seismo!rick 43 * 44 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). 45 * N.B.: this belongs in netinet, not net, the way it stands now. 46 * Should have a link-layer type designation, but wouldn't be 47 * backwards-compatible. 48 * 49 * Converted to 4.3BSD Beta by Chris Torek. 50 * Other changes made at Berkeley, based in part on code by Kirk Smith. 51 * W. Jolitz added slip abort. 52 * 53 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov). 54 * Added priority queuing for "interactive" traffic; hooks for TCP 55 * header compression; ICMP filtering (at 2400 baud, some cretin 56 * pinging you can use up all your bandwidth). Made low clist behavior 57 * more robust and slightly less likely to hang serial line. 58 * Sped up a bunch of things. 59 * 60 * Note that splimp() is used throughout to block both (tty) input 61 * interrupts and network activity; thus, splimp must be >= spltty. 62 */ 63 64 #include "opt_inet.h" 65 #include "opt_slip.h" 66 67 #include <sys/param.h> 68 #include <sys/systm.h> 69 #include <sys/malloc.h> 70 #include <sys/mbuf.h> 71 #include <sys/proc.h> 72 #include <sys/socket.h> 73 #include <sys/sockio.h> 74 #include <sys/fcntl.h> 75 #include <sys/signalvar.h> 76 #include <sys/tty.h> 77 #include <sys/clist.h> 78 #include <sys/kernel.h> 79 #include <sys/conf.h> 80 #include <sys/module.h> 81 #include <sys/proc.h> 82 83 #include <net/if.h> 84 #include <net/if_types.h> 85 #include <net/netisr.h> 86 87 #if INET 88 #include <netinet/in.h> 89 #include <netinet/in_systm.h> 90 #include <netinet/in_var.h> 91 #include <netinet/ip.h> 92 #else 93 #error "Huh? Slip without inet?" 94 #endif 95 96 #include <net/slcompress.h> 97 #include <net/if_slvar.h> 98 #include <net/slip.h> 99 100 #include <net/bpf.h> 101 102 static MALLOC_DEFINE(M_SL, "sl", "SLIP Interface"); 103 104 /* 105 * SLRMAX is a hard limit on input packet size. To simplify the code 106 * and improve performance, we require that packets fit in an mbuf 107 * cluster, and if we get a compressed packet, there's enough extra 108 * room to expand the header into a max length tcp/ip header (128 109 * bytes). So, SLRMAX can be at most 110 * MCLBYTES - 128 111 * 112 * SLMTU is the default transmit MTU. The transmit MTU should be kept 113 * small enough so that interactive use doesn't suffer, but large 114 * enough to provide good performance. 552 is a good choice for SLMTU 115 * because it is high enough to not fragment TCP packets being routed 116 * through this host. Packet fragmentation is bad with SLIP because 117 * fragment headers aren't compressed. The previous assumptions about 118 * the best MTU value don't really hold when using modern modems with 119 * BTLZ data compression because the modem buffers play a much larger 120 * role in interactive performance than the MTU. The MTU can be changed 121 * at any time to suit the specific environment with ifconfig(8), and 122 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 123 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 124 * handles this better). 125 * 126 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 127 * of us (i.e., in clists waiting to be picked up by the tty output 128 * interrupt). If we queue a lot of data downstream, it's immune to 129 * our t.o.s. queuing. 130 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 131 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 132 * wait is dependent on the ftp window size but that's typically 133 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 134 * the cost (in idle time on the wire) of the tty driver running 135 * off the end of its clists & having to call back slstart for a 136 * new packet. For a tty interface with any buffering at all, this 137 * cost will be zero. Even with a totally brain dead interface (like 138 * the one on a typical workstation), the cost will be <= 1 character 139 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 140 * at most 1% while maintaining good interactive response. 141 */ 142 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 143 #define SLRMAX (MCLBYTES - BUFOFFSET) 144 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 145 #ifndef SLMTU 146 #define SLMTU 552 /* default MTU */ 147 #endif 148 #define SLTMAX 1500 /* maximum MTU */ 149 #define SLIP_HIWAT roundup(50,CBSIZE) 150 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 151 152 /* 153 * SLIP ABORT ESCAPE MECHANISM: 154 * (inspired by HAYES modem escape arrangement) 155 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 156 * within window time signals a "soft" exit from slip mode by remote end 157 * if the IFF_DEBUG flag is on. 158 */ 159 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 160 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 161 #define ABT_COUNT 3 /* count of escapes for abort */ 162 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 163 164 static LIST_HEAD(sl_list, sl_softc) sl_list; 165 166 #define FRAME_END 0xc0 /* Frame End */ 167 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 168 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 169 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 170 171 static int slisstatic(int); 172 static void slmarkstatic(int); 173 static struct sl_softc *slcreate(void); 174 static void sldestroy(struct sl_softc *sc); 175 static struct mbuf *sl_btom(struct sl_softc *, int); 176 static timeout_t sl_keepalive; 177 static timeout_t sl_outfill; 178 static l_close_t slclose; 179 static l_rint_t slinput; 180 static l_ioctl_t sltioctl; 181 static l_start_t sltstart; 182 static int slioctl(struct ifnet *, u_long, caddr_t); 183 static int slopen(struct cdev *, struct tty *); 184 static int sloutput(struct ifnet *, 185 struct mbuf *, struct sockaddr *, struct rtentry *); 186 static void slstart(struct ifnet *); 187 188 static struct linesw slipdisc = { 189 .l_open = slopen, 190 .l_close = slclose, 191 .l_read = l_noread, 192 .l_write = l_nowrite, 193 .l_ioctl = sltioctl, 194 .l_rint = slinput, 195 .l_start = sltstart, 196 .l_modem = ttymodem 197 }; 198 199 /* 200 * Called from boot code to establish sl interfaces. 201 */ 202 static int 203 sl_modevent(module_t mod, int type, void *data) 204 { 205 switch (type) { 206 case MOD_LOAD: 207 ldisc_register(SLIPDISC, &slipdisc); 208 LIST_INIT(&sl_list); 209 break; 210 case MOD_UNLOAD: 211 ldisc_deregister(SLIPDISC); 212 printf("if_sl module unload - not possible for this module type\n"); 213 return EINVAL; 214 default: 215 return EOPNOTSUPP; 216 } 217 return 0; 218 } 219 220 static moduledata_t sl_mod = { 221 "if_sl", 222 sl_modevent, 223 0 224 }; 225 226 DECLARE_MODULE(if_sl, sl_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 227 228 static int *st_unit_list; 229 static size_t st_unit_max = 0; 230 231 static int 232 slisunitfree(int unit) 233 { 234 struct sl_softc *sc; 235 236 LIST_FOREACH(sc, &sl_list, sl_next) { 237 if (SL2IFP(sc)->if_dunit == unit) 238 return (0); 239 } 240 return (1); 241 } 242 243 static struct sl_softc * 244 sl_for_tty(struct tty *tp) 245 { 246 struct sl_softc *nc; 247 248 LIST_FOREACH(nc, &sl_list, sl_next) { 249 if (nc->sc_ttyp == tp) 250 return (nc); 251 } 252 return (NULL); 253 } 254 static int 255 slisstatic(int unit) 256 { 257 size_t i; 258 259 for (i = 0; i < st_unit_max; i++) 260 if (st_unit_list[i] == unit) 261 return 1; 262 return 0; 263 } 264 265 static void 266 slmarkstatic(int unit) 267 { 268 int *t; 269 270 if (slisstatic(unit)) 271 return; 272 273 MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT); 274 if (t == NULL) 275 return; 276 277 if (st_unit_list) { 278 bcopy(st_unit_list, t, sizeof(int) * st_unit_max); 279 free(st_unit_list, M_SL); 280 } 281 st_unit_list = t; 282 st_unit_list[st_unit_max] = unit; 283 st_unit_max++; 284 } 285 286 static struct sl_softc * 287 slcreate(void) 288 { 289 struct sl_softc *sc; 290 int unit; 291 struct mbuf *m; 292 293 MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO); 294 sc->sc_ifp = if_alloc(IFT_SLIP); 295 if (sc->sc_ifp == NULL) { 296 free(sc, M_SL); 297 return (NULL); 298 } 299 300 m = m_gethdr(M_TRYWAIT, MT_DATA); 301 if (m != NULL) { 302 MCLGET(m, M_TRYWAIT); 303 if ((m->m_flags & M_EXT) == 0) { 304 m_free(m); 305 m = NULL; 306 } 307 } 308 309 if (m == NULL) { 310 printf("sl: can't allocate buffer\n"); 311 free(sc, M_SL); 312 return (NULL); 313 } 314 315 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 316 sc->sc_mbuf = m; 317 sc->sc_buf = sc->sc_ep - SLRMAX; 318 sc->sc_mp = sc->sc_buf; 319 sl_compress_init(&sc->sc_comp, -1); 320 321 SL2IFP(sc)->if_softc = sc; 322 SL2IFP(sc)->if_mtu = SLMTU; 323 SL2IFP(sc)->if_flags = 324 #ifdef SLIP_IFF_OPTS 325 SLIP_IFF_OPTS; 326 #else 327 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST | IFF_NEEDSGIANT; 328 #endif 329 SL2IFP(sc)->if_ioctl = slioctl; 330 SL2IFP(sc)->if_output = sloutput; 331 SL2IFP(sc)->if_start = slstart; 332 SL2IFP(sc)->if_snd.ifq_maxlen = 50; 333 sc->sc_fastq.ifq_maxlen = 32; 334 SL2IFP(sc)->if_linkmib = sc; 335 SL2IFP(sc)->if_linkmiblen = sizeof *sc; 336 mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF); 337 338 /* 339 * Find a suitable unit number. 340 */ 341 for (unit=0; ; unit++) { 342 if (slisstatic(unit)) 343 continue; 344 if (!slisunitfree(unit)) 345 continue; 346 break; 347 } 348 if_initname(SL2IFP(sc), "sl", unit); 349 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 350 351 if_attach(SL2IFP(sc)); 352 bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN); 353 354 return sc; 355 } 356 357 358 /* 359 * Line specific open routine. 360 * Attach the given tty to the first available sl unit. 361 */ 362 /* ARGSUSED */ 363 static int 364 slopen(struct cdev *dev, register struct tty *tp) 365 { 366 register struct sl_softc *sc; 367 int s, error; 368 369 error = suser(curthread); 370 if (error) 371 return (error); 372 373 if ((sc = slcreate()) == NULL) 374 return (ENOBUFS); 375 376 tp->t_hotchar = FRAME_END; 377 sc->sc_ttyp = tp; 378 SL2IFP(sc)->if_baudrate = tp->t_ospeed; 379 ttyflush(tp, FREAD | FWRITE); 380 381 /* 382 * We don't use t_canq or t_rawq, so reduce their 383 * cblock resources to 0. Reserve enough cblocks 384 * for t_outq to guarantee that we can fit a full 385 * packet if the SLIP_HIWAT check allows slstart() 386 * to loop. Use the same value for the cblock 387 * limit since the reserved blocks should always 388 * be enough. Reserving cblocks probably makes 389 * the CLISTRESERVE check unnecessary and wasteful. 390 */ 391 clist_alloc_cblocks(&tp->t_canq, 0, 0); 392 clist_alloc_cblocks(&tp->t_outq, 393 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1, 394 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1); 395 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 396 397 s = splnet(); 398 if_up(SL2IFP(sc)); 399 splx(s); 400 return (0); 401 } 402 403 static void 404 sldestroy(struct sl_softc *sc) 405 { 406 bpfdetach(SL2IFP(sc)); 407 if_detach(SL2IFP(sc)); 408 if_free(SL2IFP(sc)); 409 LIST_REMOVE(sc, sl_next); 410 m_free(sc->sc_mbuf); 411 mtx_destroy(&sc->sc_fastq.ifq_mtx); 412 if (sc->bpfbuf) 413 free(sc->bpfbuf, M_SL); 414 free(sc, M_SL); 415 } 416 417 /* 418 * Line specific close routine. 419 * Detach the tty from the sl unit. 420 */ 421 static int 422 slclose(struct tty *tp, int flag) 423 { 424 register struct sl_softc *sc; 425 int s; 426 427 ttyflush(tp, FREAD | FWRITE); 428 /* 429 * XXX the placement of the following spl is misleading. tty 430 * interrupts must be blocked across line discipline switches 431 * and throughout closes to avoid races. 432 */ 433 s = splimp(); /* actually, max(spltty, splnet) */ 434 clist_free_cblocks(&tp->t_outq); 435 sc = sl_for_tty(tp); 436 if (sc != NULL) { 437 if (sc->sc_outfill) { 438 sc->sc_outfill = 0; 439 untimeout(sl_outfill, sc, sc->sc_ofhandle); 440 } 441 if (sc->sc_keepalive) { 442 sc->sc_keepalive = 0; 443 untimeout(sl_keepalive, sc, sc->sc_kahandle); 444 } 445 if_down(SL2IFP(sc)); 446 sc->sc_ttyp = NULL; 447 sldestroy(sc); 448 } 449 splx(s); 450 return 0; 451 } 452 453 /* 454 * Line specific (tty) ioctl routine. 455 * Provide a way to get the sl unit number. 456 */ 457 /* ARGSUSED */ 458 static int 459 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, 460 struct thread *td) 461 { 462 struct sl_softc *sc = sl_for_tty(tp); 463 int s, unit, wasup; 464 465 s = splimp(); 466 switch (cmd) { 467 case SLIOCGUNIT: 468 *(int *)data = SL2IFP(sc)->if_dunit; 469 break; 470 471 case SLIOCSUNIT: 472 unit = *(u_int *)data; 473 if (unit < 0) { 474 splx(s); 475 return (ENXIO); 476 } 477 if (SL2IFP(sc)->if_dunit != unit) { 478 if (!slisunitfree(unit)) { 479 splx(s); 480 return (ENXIO); 481 } 482 483 wasup = SL2IFP(sc)->if_flags & IFF_UP; 484 bpfdetach(SL2IFP(sc)); 485 if_detach(SL2IFP(sc)); 486 LIST_REMOVE(sc, sl_next); 487 if_initname(SL2IFP(sc), "sl", unit); 488 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 489 if_attach(SL2IFP(sc)); 490 bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN); 491 if (wasup) 492 if_up(SL2IFP(sc)); 493 else 494 if_down(SL2IFP(sc)); 495 clist_alloc_cblocks(&tp->t_outq, 496 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1, 497 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1); 498 } 499 slmarkstatic(unit); 500 break; 501 502 case SLIOCSKEEPAL: 503 sc->sc_keepalive = *(u_int *)data * hz; 504 if (sc->sc_keepalive) { 505 sc->sc_flags |= SC_KEEPALIVE; 506 sc->sc_kahandle = timeout(sl_keepalive, sc, 507 sc->sc_keepalive); 508 } else { 509 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 510 untimeout(sl_keepalive, sc, sc->sc_kahandle); 511 sc->sc_flags &= ~SC_KEEPALIVE; 512 } 513 } 514 break; 515 516 case SLIOCGKEEPAL: 517 *(int *)data = sc->sc_keepalive / hz; 518 break; 519 520 case SLIOCSOUTFILL: 521 sc->sc_outfill = *(u_int *)data * hz; 522 if (sc->sc_outfill) { 523 sc->sc_flags |= SC_OUTWAIT; 524 sc->sc_ofhandle = timeout(sl_outfill, sc, 525 sc->sc_outfill); 526 } else { 527 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 528 untimeout(sl_outfill, sc, sc->sc_ofhandle); 529 sc->sc_flags &= ~SC_OUTWAIT; 530 } 531 } 532 break; 533 534 case SLIOCGOUTFILL: 535 *(int *)data = sc->sc_outfill / hz; 536 break; 537 538 default: 539 splx(s); 540 return (ENOIOCTL); 541 } 542 splx(s); 543 return (0); 544 } 545 546 /* 547 * Queue a packet. Start transmission if not active. 548 * Compression happens in slstart; if we do it here, IP TOS 549 * will cause us to not compress "background" packets, because 550 * ordering gets trashed. It can be done for all packets in slstart. 551 */ 552 static int 553 sloutput(struct ifnet *ifp, register struct mbuf *m, struct sockaddr *dst, 554 struct rtentry *rtp) 555 { 556 register struct sl_softc *sc = ifp->if_softc; 557 register struct ip *ip; 558 int error; 559 560 /* 561 * `Cannot happen' (see slioctl). Someday we will extend 562 * the line protocol to support other address families. 563 */ 564 if (dst->sa_family != AF_INET) { 565 if_printf(ifp, "af%d not supported\n", dst->sa_family); 566 m_freem(m); 567 SL2IFP(sc)->if_noproto++; 568 return (EAFNOSUPPORT); 569 } 570 571 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 572 m_freem(m); 573 return (ENETDOWN); 574 } 575 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 576 m_freem(m); 577 return (EHOSTUNREACH); 578 } 579 ip = mtod(m, struct ip *); 580 if (SL2IFP(sc)->if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 581 m_freem(m); 582 return (ENETRESET); /* XXX ? */ 583 } 584 if (ip->ip_tos & IPTOS_LOWDELAY && 585 !ALTQ_IS_ENABLED(&SL2IFP(sc)->if_snd)) 586 error = !(IF_HANDOFF(&sc->sc_fastq, m, SL2IFP(sc))); 587 else 588 IFQ_HANDOFF(SL2IFP(sc), m, error); 589 if (error) { 590 SL2IFP(sc)->if_oerrors++; 591 return (ENOBUFS); 592 } 593 return (0); 594 } 595 596 static void 597 slstart(struct ifnet *ifp) 598 { 599 struct sl_softc *sc = ifp->if_softc; 600 int s; 601 602 s = splimp(); 603 if (sc->sc_ttyp->t_outq.c_cc == 0) 604 sltstart(sc->sc_ttyp); 605 splx(s); 606 } 607 608 /* 609 * Start output on interface. Get another datagram 610 * to send from the interface queue and map it to 611 * the interface before starting output. 612 */ 613 static int 614 sltstart(struct tty *tp) 615 { 616 register struct sl_softc *sc = sl_for_tty(tp); 617 register struct mbuf *m; 618 register u_char *cp; 619 register struct ip *ip; 620 int s; 621 register int len = 0; 622 623 GIANT_REQUIRED; /* tty */ 624 625 for (;;) { 626 /* 627 * Call output process whether or not there is more in the 628 * output queue. We are being called in lieu of ttstart 629 * and must do what it would. 630 */ 631 (*tp->t_oproc)(tp); 632 633 if (tp->t_outq.c_cc != 0) { 634 if (sc != NULL) 635 sc->sc_flags &= ~SC_OUTWAIT; 636 if (tp->t_outq.c_cc > SLIP_HIWAT) 637 return 0; 638 } 639 640 /* 641 * This happens briefly when the line shuts down. 642 */ 643 if (sc == NULL) 644 return 0; 645 646 /* 647 * Get a packet and send it to the interface. 648 */ 649 s = splimp(); 650 IF_DEQUEUE(&sc->sc_fastq, m); 651 if (m) 652 SL2IFP(sc)->if_omcasts++; /* XXX */ 653 else 654 IF_DEQUEUE(&SL2IFP(sc)->if_snd, m); 655 splx(s); 656 if (m == NULL) 657 return 0; 658 659 /* 660 * We do the header compression here rather than in sloutput 661 * because the packets will be out of order if we are using TOS 662 * queueing, and the connection id compression will get 663 * munged when this happens. 664 */ 665 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) { 666 /* 667 * We need to save the TCP/IP header before it's 668 * compressed. To avoid complicated code, we just 669 * copy the entire packet into a stack buffer (since 670 * this is a serial line, packets should be short 671 * and/or the copy should be negligible cost compared 672 * to the packet transmission time). 673 */ 674 register struct mbuf *m1 = m; 675 register u_char *cp; 676 677 if (sc->bpfbuf == NULL) 678 MALLOC(sc->bpfbuf, u_char *, 679 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT); 680 681 if (sc->bpfbuf) { 682 cp = sc->bpfbuf + SLIP_HDRLEN; 683 len = 0; 684 do { 685 register int mlen = m1->m_len; 686 687 bcopy(mtod(m1, caddr_t), cp, mlen); 688 cp += mlen; 689 len += mlen; 690 } while ((m1 = m1->m_next) != NULL); 691 } 692 } 693 ip = mtod(m, struct ip *); 694 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 695 if (SL2IFP(sc)->if_flags & SC_COMPRESS) 696 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 697 &sc->sc_comp, 1); 698 } 699 if (bpf_peers_present(SL2IFP(sc)->if_bpf) && sc->bpfbuf) { 700 /* 701 * Put the SLIP pseudo-"link header" in place. The 702 * compressed header is now at the beginning of the 703 * mbuf. 704 */ 705 sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT; 706 bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN); 707 BPF_TAP(SL2IFP(sc), sc->bpfbuf, len + SLIP_HDRLEN); 708 } 709 710 /* 711 * If system is getting low on clists, just flush our 712 * output queue (if the stuff was important, it'll get 713 * retransmitted). Note that SLTMAX is used instead of 714 * the current if_mtu setting because connections that 715 * have already been established still use the original 716 * (possibly larger) mss. 717 */ 718 if (cfreecount < CLISTRESERVE + SLTMAX) { 719 m_freem(m); 720 SL2IFP(sc)->if_collisions++; 721 continue; 722 } 723 724 sc->sc_flags &= ~SC_OUTWAIT; 725 /* 726 * The extra FRAME_END will start up a new packet, and thus 727 * will flush any accumulated garbage. We do this whenever 728 * the line may have been idle for some time. 729 */ 730 if (tp->t_outq.c_cc == 0) { 731 ++SL2IFP(sc)->if_obytes; 732 (void) putc(FRAME_END, &tp->t_outq); 733 } 734 735 while (m) { 736 register u_char *ep; 737 738 cp = mtod(m, u_char *); ep = cp + m->m_len; 739 while (cp < ep) { 740 /* 741 * Find out how many bytes in the string we can 742 * handle without doing something special. 743 */ 744 register u_char *bp = cp; 745 746 while (cp < ep) { 747 switch (*cp++) { 748 case FRAME_ESCAPE: 749 case FRAME_END: 750 --cp; 751 goto out; 752 } 753 } 754 out: 755 if (cp > bp) { 756 /* 757 * Put n characters at once 758 * into the tty output queue. 759 */ 760 if (b_to_q((char *)bp, cp - bp, 761 &tp->t_outq)) 762 break; 763 SL2IFP(sc)->if_obytes += cp - bp; 764 } 765 /* 766 * If there are characters left in the mbuf, 767 * the first one must be special.. 768 * Put it out in a different form. 769 */ 770 if (cp < ep) { 771 if (putc(FRAME_ESCAPE, &tp->t_outq)) 772 break; 773 if (putc(*cp++ == FRAME_ESCAPE ? 774 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 775 &tp->t_outq)) { 776 (void) unputc(&tp->t_outq); 777 break; 778 } 779 SL2IFP(sc)->if_obytes += 2; 780 } 781 } 782 m = m_free(m); 783 } 784 785 if (putc(FRAME_END, &tp->t_outq)) { 786 /* 787 * Not enough room. Remove a char to make room 788 * and end the packet normally. 789 * If you get many collisions (more than one or two 790 * a day) you probably do not have enough clists 791 * and you should increase "nclist" in param.c. 792 */ 793 (void) unputc(&tp->t_outq); 794 (void) putc(FRAME_END, &tp->t_outq); 795 SL2IFP(sc)->if_collisions++; 796 } else { 797 ++SL2IFP(sc)->if_obytes; 798 SL2IFP(sc)->if_opackets++; 799 } 800 } 801 return 0; 802 } 803 804 /* 805 * Copy data buffer to mbuf chain; add ifnet pointer. 806 */ 807 static struct mbuf * 808 sl_btom(struct sl_softc *sc, register int len) 809 { 810 struct mbuf *m, *newm; 811 812 MGETHDR(m, M_DONTWAIT, MT_DATA); 813 if (m == NULL) 814 return (NULL); 815 816 /* 817 * If we have more than MHLEN bytes, it's cheaper to 818 * queue the cluster we just filled & allocate a new one 819 * for the input buffer. Otherwise, fill the mbuf we 820 * allocated above. Note that code in the input routine 821 * guarantees that packet will fit in a cluster. 822 */ 823 if (len >= MHLEN) { 824 MCLGET(m, M_DONTWAIT); 825 if ((m->m_flags & M_EXT) == 0) { 826 /* 827 * we couldn't get a cluster - if memory's this 828 * low, it's time to start dropping packets. 829 */ 830 (void) m_free(m); 831 return (NULL); 832 } 833 /* Swap the new and old clusters */ 834 newm = m; 835 m = sc->sc_mbuf; 836 sc->sc_mbuf = newm; 837 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE; 838 839 m->m_data = (caddr_t)sc->sc_buf; 840 } else 841 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 842 843 m->m_len = len; 844 m->m_pkthdr.len = len; 845 m->m_pkthdr.rcvif = SL2IFP(sc); 846 return (m); 847 } 848 849 /* 850 * tty interface receiver interrupt. 851 */ 852 static int 853 slinput(int c, struct tty *tp) 854 { 855 register struct sl_softc *sc; 856 register struct mbuf *m; 857 register int len; 858 u_char chdr[CHDR_LEN]; 859 860 tk_nin++; 861 sc = sl_for_tty(tp); 862 if (sc == NULL) 863 return 0; 864 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 865 sc->sc_flags |= SC_ERROR; 866 return 0; 867 } 868 c &= TTY_CHARMASK; 869 870 ++SL2IFP(sc)->if_ibytes; 871 872 if (SL2IFP(sc)->if_flags & IFF_DEBUG) { 873 if (c == ABT_ESC) { 874 /* 875 * If we have a previous abort, see whether 876 * this one is within the time limit. 877 */ 878 if (sc->sc_abortcount && 879 time_second >= sc->sc_starttime + ABT_WINDOW) 880 sc->sc_abortcount = 0; 881 /* 882 * If we see an abort after "idle" time, count it; 883 * record when the first abort escape arrived. 884 */ 885 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 886 if (++sc->sc_abortcount == 1) 887 sc->sc_starttime = time_second; 888 if (sc->sc_abortcount >= ABT_COUNT) { 889 slclose(tp,0); 890 return 0; 891 } 892 } 893 } else 894 sc->sc_abortcount = 0; 895 sc->sc_lasttime = time_second; 896 } 897 898 switch (c) { 899 900 case TRANS_FRAME_ESCAPE: 901 if (sc->sc_escape) 902 c = FRAME_ESCAPE; 903 break; 904 905 case TRANS_FRAME_END: 906 if (sc->sc_escape) 907 c = FRAME_END; 908 break; 909 910 case FRAME_ESCAPE: 911 sc->sc_escape = 1; 912 return 0; 913 914 case FRAME_END: 915 sc->sc_flags &= ~SC_KEEPALIVE; 916 if(sc->sc_flags & SC_ERROR) { 917 sc->sc_flags &= ~SC_ERROR; 918 goto newpack; 919 } 920 len = sc->sc_mp - sc->sc_buf; 921 if (len < 3) 922 /* less than min length packet - ignore */ 923 goto newpack; 924 925 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) { 926 /* 927 * Save the compressed header, so we 928 * can tack it on later. Note that we 929 * will end up copying garbage in some 930 * cases but this is okay. We remember 931 * where the buffer started so we can 932 * compute the new header length. 933 */ 934 bcopy(sc->sc_buf, chdr, CHDR_LEN); 935 } 936 937 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 938 if (c & 0x80) 939 c = TYPE_COMPRESSED_TCP; 940 else if (c == TYPE_UNCOMPRESSED_TCP) 941 *sc->sc_buf &= 0x4f; /* XXX */ 942 /* 943 * We've got something that's not an IP packet. 944 * If compression is enabled, try to decompress it. 945 * Otherwise, if `auto-enable' compression is on and 946 * it's a reasonable packet, decompress it and then 947 * enable compression. Otherwise, drop it. 948 */ 949 if (SL2IFP(sc)->if_flags & SC_COMPRESS) { 950 len = sl_uncompress_tcp(&sc->sc_buf, len, 951 (u_int)c, &sc->sc_comp); 952 if (len <= 0) 953 goto error; 954 } else if ((SL2IFP(sc)->if_flags & SC_AUTOCOMP) && 955 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 956 len = sl_uncompress_tcp(&sc->sc_buf, len, 957 (u_int)c, &sc->sc_comp); 958 if (len <= 0) 959 goto error; 960 SL2IFP(sc)->if_flags |= SC_COMPRESS; 961 } else 962 goto error; 963 } 964 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) { 965 /* 966 * Put the SLIP pseudo-"link header" in place. 967 * We couldn't do this any earlier since 968 * decompression probably moved the buffer 969 * pointer. Then, invoke BPF. 970 */ 971 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 972 973 hp[SLX_DIR] = SLIPDIR_IN; 974 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 975 BPF_TAP(SL2IFP(sc), hp, len + SLIP_HDRLEN); 976 } 977 m = sl_btom(sc, len); 978 if (m == NULL) 979 goto error; 980 981 SL2IFP(sc)->if_ipackets++; 982 983 if ((SL2IFP(sc)->if_flags & IFF_UP) == 0) { 984 m_freem(m); 985 goto newpack; 986 } 987 if (netisr_queue(NETISR_IP, m)) { /* (0) on success. */ 988 SL2IFP(sc)->if_ierrors++; 989 SL2IFP(sc)->if_iqdrops++; 990 } 991 goto newpack; 992 } 993 if (sc->sc_mp < sc->sc_ep) { 994 *sc->sc_mp++ = c; 995 sc->sc_escape = 0; 996 return 0; 997 } 998 999 /* can't put lower; would miss an extra frame */ 1000 sc->sc_flags |= SC_ERROR; 1001 1002 error: 1003 SL2IFP(sc)->if_ierrors++; 1004 newpack: 1005 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 1006 sc->sc_escape = 0; 1007 return 0; 1008 } 1009 1010 /* 1011 * Process an ioctl request. 1012 */ 1013 static int 1014 slioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 1015 { 1016 register struct ifaddr *ifa = (struct ifaddr *)data; 1017 register struct ifreq *ifr = (struct ifreq *)data; 1018 register int s, error = 0; 1019 struct sl_softc *sc = ifp->if_softc; 1020 1021 s = splimp(); 1022 1023 switch (cmd) { 1024 1025 case SIOCSIFFLAGS: 1026 /* 1027 * if.c will set the interface up even if we 1028 * don't want it to. 1029 */ 1030 if (sc->sc_ttyp == NULL) { 1031 ifp->if_flags &= ~IFF_UP; 1032 } 1033 break; 1034 case SIOCSIFADDR: 1035 /* 1036 * This is "historical" - set the interface up when 1037 * setting the address. 1038 */ 1039 if (ifa->ifa_addr->sa_family == AF_INET) { 1040 if (sc->sc_ttyp != NULL) 1041 ifp->if_flags |= IFF_UP; 1042 } else { 1043 error = EAFNOSUPPORT; 1044 } 1045 break; 1046 1047 case SIOCSIFDSTADDR: 1048 if (ifa->ifa_addr->sa_family != AF_INET) 1049 error = EAFNOSUPPORT; 1050 break; 1051 1052 case SIOCADDMULTI: 1053 case SIOCDELMULTI: 1054 break; 1055 1056 case SIOCSIFMTU: 1057 /* 1058 * Set the interface MTU. 1059 */ 1060 if (ifr->ifr_mtu > SLTMAX) 1061 error = EINVAL; 1062 else { 1063 struct tty *tp; 1064 1065 ifp->if_mtu = ifr->ifr_mtu; 1066 tp = sc->sc_ttyp; 1067 if (tp != NULL) 1068 clist_alloc_cblocks(&tp->t_outq, 1069 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1070 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1071 } 1072 break; 1073 1074 default: 1075 error = EINVAL; 1076 } 1077 splx(s); 1078 return (error); 1079 } 1080 1081 static void 1082 sl_keepalive(void *chan) 1083 { 1084 struct sl_softc *sc = chan; 1085 1086 if (sc->sc_keepalive) { 1087 if (sc->sc_flags & SC_KEEPALIVE) { 1088 if (sc->sc_ttyp->t_pgrp != NULL) { 1089 PGRP_LOCK(sc->sc_ttyp->t_pgrp); 1090 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1091 PGRP_UNLOCK(sc->sc_ttyp->t_pgrp); 1092 } 1093 } else 1094 sc->sc_flags |= SC_KEEPALIVE; 1095 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1096 } else { 1097 sc->sc_flags &= ~SC_KEEPALIVE; 1098 } 1099 } 1100 1101 static void 1102 sl_outfill(void *chan) 1103 { 1104 struct sl_softc *sc = chan; 1105 register struct tty *tp = sc->sc_ttyp; 1106 int s; 1107 1108 if (sc->sc_outfill && tp != NULL) { 1109 if (sc->sc_flags & SC_OUTWAIT) { 1110 s = splimp (); 1111 ++SL2IFP(sc)->if_obytes; 1112 (void) putc(FRAME_END, &tp->t_outq); 1113 (*tp->t_oproc)(tp); 1114 splx (s); 1115 } else 1116 sc->sc_flags |= SC_OUTWAIT; 1117 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1118 } else { 1119 sc->sc_flags &= ~SC_OUTWAIT; 1120 } 1121 }
Cache object: 80fdfb0c1be3c455a2ac87fb6c2d1042
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