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/5.4/sys/net/if_sl.c 145335 2005-04-20 19:11:07Z cvs2svn $ 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 *nc; 235 236 LIST_FOREACH(nc, &sl_list, sl_next) { 237 if (nc->sc_if.if_dunit == unit) 238 return (0); 239 } 240 return (1); 241 } 242 243 static int 244 slisstatic(int unit) 245 { 246 size_t i; 247 248 for (i = 0; i < st_unit_max; i++) 249 if (st_unit_list[i] == unit) 250 return 1; 251 return 0; 252 } 253 254 static void 255 slmarkstatic(int unit) 256 { 257 int *t; 258 259 if (slisstatic(unit)) 260 return; 261 262 MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT); 263 if (t == NULL) 264 return; 265 266 if (st_unit_list) { 267 bcopy(st_unit_list, t, sizeof(int) * st_unit_max); 268 free(st_unit_list, M_SL); 269 } 270 st_unit_list = t; 271 st_unit_list[st_unit_max] = unit; 272 st_unit_max++; 273 } 274 275 static struct sl_softc * 276 slcreate(void) 277 { 278 struct sl_softc *sc; 279 int unit; 280 struct mbuf *m; 281 282 MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO); 283 284 m = m_gethdr(M_TRYWAIT, MT_DATA); 285 if (m != NULL) { 286 MCLGET(m, M_TRYWAIT); 287 if ((m->m_flags & M_EXT) == 0) { 288 m_free(m); 289 m = NULL; 290 } 291 } 292 293 if (m == NULL) { 294 printf("sl: can't allocate buffer\n"); 295 free(sc, M_SL); 296 return (NULL); 297 } 298 299 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE; 300 sc->sc_mbuf = m; 301 sc->sc_buf = sc->sc_ep - SLRMAX; 302 sc->sc_mp = sc->sc_buf; 303 sl_compress_init(&sc->sc_comp, -1); 304 305 sc->sc_if.if_softc = sc; 306 sc->sc_if.if_mtu = SLMTU; 307 sc->sc_if.if_flags = 308 #ifdef SLIP_IFF_OPTS 309 SLIP_IFF_OPTS; 310 #else 311 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST | IFF_NEEDSGIANT; 312 #endif 313 sc->sc_if.if_type = IFT_SLIP; 314 sc->sc_if.if_ioctl = slioctl; 315 sc->sc_if.if_output = sloutput; 316 sc->sc_if.if_start = slstart; 317 sc->sc_if.if_snd.ifq_maxlen = 50; 318 sc->sc_fastq.ifq_maxlen = 32; 319 sc->sc_if.if_linkmib = sc; 320 sc->sc_if.if_linkmiblen = sizeof *sc; 321 mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF); 322 323 /* 324 * Find a suitable unit number. 325 */ 326 for (unit=0; ; unit++) { 327 if (slisstatic(unit)) 328 continue; 329 if (!slisunitfree(unit)) 330 continue; 331 break; 332 } 333 if_initname(&sc->sc_if, "sl", unit); 334 LIST_INSERT_HEAD(&sl_list, sc, sl_next); 335 336 if_attach(&sc->sc_if); 337 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 338 339 return sc; 340 } 341 342 343 /* 344 * Line specific open routine. 345 * Attach the given tty to the first available sl unit. 346 */ 347 /* ARGSUSED */ 348 static int 349 slopen(struct cdev *dev, register struct tty *tp) 350 { 351 register struct sl_softc *sc; 352 int s, error; 353 354 error = suser(curthread); 355 if (error) 356 return (error); 357 358 if ((sc = slcreate()) == NULL) 359 return (ENOBUFS); 360 361 tp->t_hotchar = FRAME_END; 362 tp->t_sc = (caddr_t)sc; 363 sc->sc_ttyp = tp; 364 sc->sc_if.if_baudrate = tp->t_ospeed; 365 ttyflush(tp, FREAD | FWRITE); 366 367 /* 368 * We don't use t_canq or t_rawq, so reduce their 369 * cblock resources to 0. Reserve enough cblocks 370 * for t_outq to guarantee that we can fit a full 371 * packet if the SLIP_HIWAT check allows slstart() 372 * to loop. Use the same value for the cblock 373 * limit since the reserved blocks should always 374 * be enough. Reserving cblocks probably makes 375 * the CLISTRESERVE check unnecessary and wasteful. 376 */ 377 clist_alloc_cblocks(&tp->t_canq, 0, 0); 378 clist_alloc_cblocks(&tp->t_outq, 379 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 380 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 381 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 382 383 s = splnet(); 384 if_up(&sc->sc_if); 385 splx(s); 386 return (0); 387 } 388 389 static void 390 sldestroy(struct sl_softc *sc) 391 { 392 bpfdetach(&sc->sc_if); 393 if_detach(&sc->sc_if); 394 LIST_REMOVE(sc, sl_next); 395 m_free(sc->sc_mbuf); 396 mtx_destroy(&sc->sc_fastq.ifq_mtx); 397 if (sc->bpfbuf) 398 free(sc->bpfbuf, M_SL); 399 free(sc, M_SL); 400 } 401 402 /* 403 * Line specific close routine. 404 * Detach the tty from the sl unit. 405 */ 406 static int 407 slclose(struct tty *tp, int flag) 408 { 409 register struct sl_softc *sc; 410 int s; 411 412 ttyflush(tp, FREAD | FWRITE); 413 /* 414 * XXX the placement of the following spl is misleading. tty 415 * interrupts must be blocked across line discipline switches 416 * and throughout closes to avoid races. 417 */ 418 s = splimp(); /* actually, max(spltty, splnet) */ 419 clist_free_cblocks(&tp->t_outq); 420 sc = (struct sl_softc *)tp->t_sc; 421 if (sc != NULL) { 422 if (sc->sc_outfill) { 423 sc->sc_outfill = 0; 424 untimeout(sl_outfill, sc, sc->sc_ofhandle); 425 } 426 if (sc->sc_keepalive) { 427 sc->sc_keepalive = 0; 428 untimeout(sl_keepalive, sc, sc->sc_kahandle); 429 } 430 if_down(&sc->sc_if); 431 sc->sc_ttyp = NULL; 432 tp->t_sc = NULL; 433 sldestroy(sc); 434 } 435 splx(s); 436 return 0; 437 } 438 439 /* 440 * Line specific (tty) ioctl routine. 441 * Provide a way to get the sl unit number. 442 */ 443 /* ARGSUSED */ 444 static int 445 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, 446 struct thread *td) 447 { 448 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 449 int s, unit, wasup; 450 451 s = splimp(); 452 switch (cmd) { 453 case SLIOCGUNIT: 454 *(int *)data = sc->sc_if.if_dunit; 455 break; 456 457 case SLIOCSUNIT: 458 unit = *(u_int *)data; 459 if (unit < 0) { 460 splx(s); 461 return (ENXIO); 462 } 463 if (sc->sc_if.if_dunit != unit) { 464 if (!slisunitfree(unit)) { 465 splx(s); 466 return (ENXIO); 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(struct ifnet *ifp, register struct mbuf *m, struct sockaddr *dst, 540 struct rtentry *rtp) 541 { 542 register struct sl_softc *sc = ifp->if_softc; 543 register struct ip *ip; 544 int error; 545 546 /* 547 * `Cannot happen' (see slioctl). Someday we will extend 548 * the line protocol to support other address families. 549 */ 550 if (dst->sa_family != AF_INET) { 551 if_printf(ifp, "af%d not supported\n", dst->sa_family); 552 m_freem(m); 553 sc->sc_if.if_noproto++; 554 return (EAFNOSUPPORT); 555 } 556 557 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 558 m_freem(m); 559 return (ENETDOWN); 560 } 561 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 562 m_freem(m); 563 return (EHOSTUNREACH); 564 } 565 ip = mtod(m, struct ip *); 566 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 567 m_freem(m); 568 return (ENETRESET); /* XXX ? */ 569 } 570 if (ip->ip_tos & IPTOS_LOWDELAY && 571 !ALTQ_IS_ENABLED(&sc->sc_if.if_snd)) 572 error = !(IF_HANDOFF(&sc->sc_fastq, m, &sc->sc_if)); 573 else 574 IFQ_HANDOFF(&sc->sc_if, m, error); 575 if (error) { 576 sc->sc_if.if_oerrors++; 577 return (ENOBUFS); 578 } 579 return (0); 580 } 581 582 static void 583 slstart(struct ifnet *ifp) 584 { 585 struct sl_softc *sc = ifp->if_softc; 586 int s; 587 588 s = splimp(); 589 if (sc->sc_ttyp->t_outq.c_cc == 0) 590 sltstart(sc->sc_ttyp); 591 splx(s); 592 } 593 594 /* 595 * Start output on interface. Get another datagram 596 * to send from the interface queue and map it to 597 * the interface before starting output. 598 */ 599 static int 600 sltstart(register struct tty *tp) 601 { 602 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 603 register struct mbuf *m; 604 register u_char *cp; 605 register struct ip *ip; 606 int s; 607 register int len = 0; 608 609 GIANT_REQUIRED; /* tty */ 610 611 for (;;) { 612 /* 613 * Call output process whether or not there is more in the 614 * output queue. We are being called in lieu of ttstart 615 * and must do what it would. 616 */ 617 (*tp->t_oproc)(tp); 618 619 if (tp->t_outq.c_cc != 0) { 620 if (sc != NULL) 621 sc->sc_flags &= ~SC_OUTWAIT; 622 if (tp->t_outq.c_cc > SLIP_HIWAT) 623 return 0; 624 } 625 626 /* 627 * This happens briefly when the line shuts down. 628 */ 629 if (sc == NULL) 630 return 0; 631 632 /* 633 * Get a packet and send it to the interface. 634 */ 635 s = splimp(); 636 IF_DEQUEUE(&sc->sc_fastq, m); 637 if (m) 638 sc->sc_if.if_omcasts++; /* XXX */ 639 else 640 IF_DEQUEUE(&sc->sc_if.if_snd, m); 641 splx(s); 642 if (m == NULL) 643 return 0; 644 645 /* 646 * We do the header compression here rather than in sloutput 647 * because the packets will be out of order if we are using TOS 648 * queueing, and the connection id compression will get 649 * munged when this happens. 650 */ 651 if (sc->sc_if.if_bpf) { 652 /* 653 * We need to save the TCP/IP header before it's 654 * compressed. To avoid complicated code, we just 655 * copy the entire packet into a stack buffer (since 656 * this is a serial line, packets should be short 657 * and/or the copy should be negligible cost compared 658 * to the packet transmission time). 659 */ 660 register struct mbuf *m1 = m; 661 register u_char *cp; 662 663 if (sc->bpfbuf == NULL) 664 MALLOC(sc->bpfbuf, u_char *, 665 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT); 666 667 if (sc->bpfbuf) { 668 cp = sc->bpfbuf + SLIP_HDRLEN; 669 len = 0; 670 do { 671 register int mlen = m1->m_len; 672 673 bcopy(mtod(m1, caddr_t), cp, mlen); 674 cp += mlen; 675 len += mlen; 676 } while ((m1 = m1->m_next) != NULL); 677 } 678 } 679 ip = mtod(m, struct ip *); 680 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 681 if (sc->sc_if.if_flags & SC_COMPRESS) 682 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 683 &sc->sc_comp, 1); 684 } 685 if (sc->sc_if.if_bpf && sc->bpfbuf) { 686 /* 687 * Put the SLIP pseudo-"link header" in place. The 688 * compressed header is now at the beginning of the 689 * mbuf. 690 */ 691 sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT; 692 bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN); 693 BPF_TAP(&sc->sc_if, sc->bpfbuf, len + SLIP_HDRLEN); 694 } 695 696 /* 697 * If system is getting low on clists, just flush our 698 * output queue (if the stuff was important, it'll get 699 * retransmitted). Note that SLTMAX is used instead of 700 * the current if_mtu setting because connections that 701 * have already been established still use the original 702 * (possibly larger) mss. 703 */ 704 if (cfreecount < CLISTRESERVE + SLTMAX) { 705 m_freem(m); 706 sc->sc_if.if_collisions++; 707 continue; 708 } 709 710 sc->sc_flags &= ~SC_OUTWAIT; 711 /* 712 * The extra FRAME_END will start up a new packet, and thus 713 * will flush any accumulated garbage. We do this whenever 714 * the line may have been idle for some time. 715 */ 716 if (tp->t_outq.c_cc == 0) { 717 ++sc->sc_if.if_obytes; 718 (void) putc(FRAME_END, &tp->t_outq); 719 } 720 721 while (m) { 722 register u_char *ep; 723 724 cp = mtod(m, u_char *); ep = cp + m->m_len; 725 while (cp < ep) { 726 /* 727 * Find out how many bytes in the string we can 728 * handle without doing something special. 729 */ 730 register u_char *bp = cp; 731 732 while (cp < ep) { 733 switch (*cp++) { 734 case FRAME_ESCAPE: 735 case FRAME_END: 736 --cp; 737 goto out; 738 } 739 } 740 out: 741 if (cp > bp) { 742 /* 743 * Put n characters at once 744 * into the tty output queue. 745 */ 746 if (b_to_q((char *)bp, cp - bp, 747 &tp->t_outq)) 748 break; 749 sc->sc_if.if_obytes += cp - bp; 750 } 751 /* 752 * If there are characters left in the mbuf, 753 * the first one must be special.. 754 * Put it out in a different form. 755 */ 756 if (cp < ep) { 757 if (putc(FRAME_ESCAPE, &tp->t_outq)) 758 break; 759 if (putc(*cp++ == FRAME_ESCAPE ? 760 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 761 &tp->t_outq)) { 762 (void) unputc(&tp->t_outq); 763 break; 764 } 765 sc->sc_if.if_obytes += 2; 766 } 767 } 768 m = m_free(m); 769 } 770 771 if (putc(FRAME_END, &tp->t_outq)) { 772 /* 773 * Not enough room. Remove a char to make room 774 * and end the packet normally. 775 * If you get many collisions (more than one or two 776 * a day) you probably do not have enough clists 777 * and you should increase "nclist" in param.c. 778 */ 779 (void) unputc(&tp->t_outq); 780 (void) putc(FRAME_END, &tp->t_outq); 781 sc->sc_if.if_collisions++; 782 } else { 783 ++sc->sc_if.if_obytes; 784 sc->sc_if.if_opackets++; 785 } 786 } 787 return 0; 788 } 789 790 /* 791 * Copy data buffer to mbuf chain; add ifnet pointer. 792 */ 793 static struct mbuf * 794 sl_btom(struct sl_softc *sc, register int len) 795 { 796 struct mbuf *m, *newm; 797 798 MGETHDR(m, M_DONTWAIT, MT_DATA); 799 if (m == NULL) 800 return (NULL); 801 802 /* 803 * If we have more than MHLEN bytes, it's cheaper to 804 * queue the cluster we just filled & allocate a new one 805 * for the input buffer. Otherwise, fill the mbuf we 806 * allocated above. Note that code in the input routine 807 * guarantees that packet will fit in a cluster. 808 */ 809 if (len >= MHLEN) { 810 MCLGET(m, M_DONTWAIT); 811 if ((m->m_flags & M_EXT) == 0) { 812 /* 813 * we couldn't get a cluster - if memory's this 814 * low, it's time to start dropping packets. 815 */ 816 (void) m_free(m); 817 return (NULL); 818 } 819 /* Swap the new and old clusters */ 820 newm = m; 821 m = sc->sc_mbuf; 822 sc->sc_mbuf = newm; 823 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE; 824 825 m->m_data = (caddr_t)sc->sc_buf; 826 } else 827 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 828 829 m->m_len = len; 830 m->m_pkthdr.len = len; 831 m->m_pkthdr.rcvif = &sc->sc_if; 832 return (m); 833 } 834 835 /* 836 * tty interface receiver interrupt. 837 */ 838 static int 839 slinput(int c, struct tty *tp) 840 { 841 register struct sl_softc *sc; 842 register struct mbuf *m; 843 register int len; 844 u_char chdr[CHDR_LEN]; 845 846 tk_nin++; 847 sc = (struct sl_softc *)tp->t_sc; 848 if (sc == NULL) 849 return 0; 850 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 851 sc->sc_flags |= SC_ERROR; 852 return 0; 853 } 854 c &= TTY_CHARMASK; 855 856 ++sc->sc_if.if_ibytes; 857 858 if (sc->sc_if.if_flags & IFF_DEBUG) { 859 if (c == ABT_ESC) { 860 /* 861 * If we have a previous abort, see whether 862 * this one is within the time limit. 863 */ 864 if (sc->sc_abortcount && 865 time_second >= sc->sc_starttime + ABT_WINDOW) 866 sc->sc_abortcount = 0; 867 /* 868 * If we see an abort after "idle" time, count it; 869 * record when the first abort escape arrived. 870 */ 871 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 872 if (++sc->sc_abortcount == 1) 873 sc->sc_starttime = time_second; 874 if (sc->sc_abortcount >= ABT_COUNT) { 875 slclose(tp,0); 876 return 0; 877 } 878 } 879 } else 880 sc->sc_abortcount = 0; 881 sc->sc_lasttime = time_second; 882 } 883 884 switch (c) { 885 886 case TRANS_FRAME_ESCAPE: 887 if (sc->sc_escape) 888 c = FRAME_ESCAPE; 889 break; 890 891 case TRANS_FRAME_END: 892 if (sc->sc_escape) 893 c = FRAME_END; 894 break; 895 896 case FRAME_ESCAPE: 897 sc->sc_escape = 1; 898 return 0; 899 900 case FRAME_END: 901 sc->sc_flags &= ~SC_KEEPALIVE; 902 if(sc->sc_flags & SC_ERROR) { 903 sc->sc_flags &= ~SC_ERROR; 904 goto newpack; 905 } 906 len = sc->sc_mp - sc->sc_buf; 907 if (len < 3) 908 /* less than min length packet - ignore */ 909 goto newpack; 910 911 if (sc->sc_if.if_bpf) { 912 /* 913 * Save the compressed header, so we 914 * can tack it on later. Note that we 915 * will end up copying garbage in some 916 * cases but this is okay. We remember 917 * where the buffer started so we can 918 * compute the new header length. 919 */ 920 bcopy(sc->sc_buf, chdr, CHDR_LEN); 921 } 922 923 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 924 if (c & 0x80) 925 c = TYPE_COMPRESSED_TCP; 926 else if (c == TYPE_UNCOMPRESSED_TCP) 927 *sc->sc_buf &= 0x4f; /* XXX */ 928 /* 929 * We've got something that's not an IP packet. 930 * If compression is enabled, try to decompress it. 931 * Otherwise, if `auto-enable' compression is on and 932 * it's a reasonable packet, decompress it and then 933 * enable compression. Otherwise, drop it. 934 */ 935 if (sc->sc_if.if_flags & SC_COMPRESS) { 936 len = sl_uncompress_tcp(&sc->sc_buf, len, 937 (u_int)c, &sc->sc_comp); 938 if (len <= 0) 939 goto error; 940 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 941 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 942 len = sl_uncompress_tcp(&sc->sc_buf, len, 943 (u_int)c, &sc->sc_comp); 944 if (len <= 0) 945 goto error; 946 sc->sc_if.if_flags |= SC_COMPRESS; 947 } else 948 goto error; 949 } 950 if (sc->sc_if.if_bpf) { 951 /* 952 * Put the SLIP pseudo-"link header" in place. 953 * We couldn't do this any earlier since 954 * decompression probably moved the buffer 955 * pointer. Then, invoke BPF. 956 */ 957 register u_char *hp = sc->sc_buf - SLIP_HDRLEN; 958 959 hp[SLX_DIR] = SLIPDIR_IN; 960 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 961 BPF_TAP(&sc->sc_if, hp, len + SLIP_HDRLEN); 962 } 963 m = sl_btom(sc, len); 964 if (m == NULL) 965 goto error; 966 967 sc->sc_if.if_ipackets++; 968 969 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 970 m_freem(m); 971 goto newpack; 972 } 973 if (netisr_queue(NETISR_IP, m)) { /* (0) on success. */ 974 sc->sc_if.if_ierrors++; 975 sc->sc_if.if_iqdrops++; 976 } 977 goto newpack; 978 } 979 if (sc->sc_mp < sc->sc_ep) { 980 *sc->sc_mp++ = c; 981 sc->sc_escape = 0; 982 return 0; 983 } 984 985 /* can't put lower; would miss an extra frame */ 986 sc->sc_flags |= SC_ERROR; 987 988 error: 989 sc->sc_if.if_ierrors++; 990 newpack: 991 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX; 992 sc->sc_escape = 0; 993 return 0; 994 } 995 996 /* 997 * Process an ioctl request. 998 */ 999 static int 1000 slioctl(struct ifnet *ifp, u_long cmd, 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(void *chan) 1069 { 1070 struct sl_softc *sc = chan; 1071 1072 if (sc->sc_keepalive) { 1073 if (sc->sc_flags & SC_KEEPALIVE) { 1074 if (sc->sc_ttyp->t_pgrp != NULL) { 1075 PGRP_LOCK(sc->sc_ttyp->t_pgrp); 1076 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1077 PGRP_UNLOCK(sc->sc_ttyp->t_pgrp); 1078 } 1079 } else 1080 sc->sc_flags |= SC_KEEPALIVE; 1081 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive); 1082 } else { 1083 sc->sc_flags &= ~SC_KEEPALIVE; 1084 } 1085 } 1086 1087 static void 1088 sl_outfill(void *chan) 1089 { 1090 struct sl_softc *sc = chan; 1091 register struct tty *tp = sc->sc_ttyp; 1092 int s; 1093 1094 if (sc->sc_outfill && tp != NULL) { 1095 if (sc->sc_flags & SC_OUTWAIT) { 1096 s = splimp (); 1097 ++sc->sc_if.if_obytes; 1098 (void) putc(FRAME_END, &tp->t_outq); 1099 (*tp->t_oproc)(tp); 1100 splx (s); 1101 } else 1102 sc->sc_flags |= SC_OUTWAIT; 1103 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill); 1104 } else { 1105 sc->sc_flags &= ~SC_OUTWAIT; 1106 } 1107 }
Cache object: bc413ccb4acb62a3b8932432904c05b2
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