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: src/sys/net/if_sl.c,v 1.84.2.2 2002/02/13 00:43:10 dillon Exp $ 35 * $DragonFly: src/sys/net/sl/if_sl.c,v 1.25 2006/07/28 02:17:40 dillon Exp $ 36 */ 37 38 /* 39 * Serial Line interface 40 * 41 * Rick Adams 42 * Center for Seismic Studies 43 * 1300 N 17th Street, Suite 1450 44 * Arlington, Virginia 22209 45 * (703)276-7900 46 * rick@seismo.ARPA 47 * seismo!rick 48 * 49 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). 50 * N.B.: this belongs in netinet, not net, the way it stands now. 51 * Should have a link-layer type designation, but wouldn't be 52 * backwards-compatible. 53 * 54 * Converted to 4.3BSD Beta by Chris Torek. 55 * Other changes made at Berkeley, based in part on code by Kirk Smith. 56 * W. Jolitz added slip abort. 57 * 58 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov). 59 * Added priority queuing for "interactive" traffic; hooks for TCP 60 * header compression; ICMP filtering (at 2400 baud, some cretin 61 * pinging you can use up all your bandwidth). Made low clist behavior 62 * more robust and slightly less likely to hang serial line. 63 * Sped up a bunch of things. 64 */ 65 66 #include "use_sl.h" 67 68 #include "opt_inet.h" 69 #if !defined(KLD_MODULE) 70 #include "opt_slip.h" 71 #endif 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/proc.h> 75 #include <sys/malloc.h> 76 #include <sys/mbuf.h> 77 #include <sys/dkstat.h> 78 #include <sys/socket.h> 79 #include <sys/sockio.h> 80 #include <sys/fcntl.h> 81 #include <sys/signalvar.h> 82 #include <sys/tty.h> 83 #include <sys/clist.h> 84 #include <sys/kernel.h> 85 #include <sys/conf.h> 86 #include <sys/thread2.h> 87 88 #include <net/if.h> 89 #include <net/if_types.h> 90 #include <net/ifq_var.h> 91 #include <net/netisr.h> 92 93 #if INET 94 #include <netinet/in.h> 95 #include <netinet/in_systm.h> 96 #include <netinet/in_var.h> 97 #include <netinet/ip.h> 98 #else 99 #error "Huh? Slip without inet?" 100 #endif 101 102 #include <net/slcompress.h> 103 #include "if_slvar.h" 104 #include <net/slip.h> 105 106 #include <net/bpf.h> 107 108 #ifdef __i386__ 109 #include <i386/isa/intr_machdep.h> 110 #endif 111 112 static void slattach (void *); 113 PSEUDO_SET(slattach, if_sl); 114 115 /* 116 * SLRMAX is a hard limit on input packet size. To simplify the code 117 * and improve performance, we require that packets fit in an mbuf 118 * cluster, and if we get a compressed packet, there's enough extra 119 * room to expand the header into a max length tcp/ip header (128 120 * bytes). So, SLRMAX can be at most 121 * MCLBYTES - 128 122 * 123 * SLMTU is the default transmit MTU. The transmit MTU should be kept 124 * small enough so that interactive use doesn't suffer, but large 125 * enough to provide good performance. 552 is a good choice for SLMTU 126 * because it is high enough to not fragment TCP packets being routed 127 * through this host. Packet fragmentation is bad with SLIP because 128 * fragment headers aren't compressed. The previous assumptions about 129 * the best MTU value don't really hold when using modern modems with 130 * BTLZ data compression because the modem buffers play a much larger 131 * role in interactive performance than the MTU. The MTU can be changed 132 * at any time to suit the specific environment with ifconfig(8), and 133 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 134 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 135 * handles this better). 136 * 137 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 138 * of us (i.e., in clists waiting to be picked up by the tty output 139 * interrupt). If we queue a lot of data downstream, it's immune to 140 * our t.o.s. queuing. 141 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 142 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 143 * wait is dependent on the ftp window size but that's typically 144 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 145 * the cost (in idle time on the wire) of the tty driver running 146 * off the end of its clists & having to call back slstart for a 147 * new packet. For a tty interface with any buffering at all, this 148 * cost will be zero. Even with a totally brain dead interface (like 149 * the one on a typical workstation), the cost will be <= 1 character 150 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 151 * at most 1% while maintaining good interactive response. 152 */ 153 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 154 #define SLRMAX (MCLBYTES - BUFOFFSET) 155 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 156 #ifndef SLMTU 157 #define SLMTU 552 /* default MTU */ 158 #endif 159 #define SLTMAX 1500 /* maximum MTU */ 160 #define SLIP_HIWAT roundup(50,CBSIZE) 161 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 162 163 /* 164 * SLIP ABORT ESCAPE MECHANISM: 165 * (inspired by HAYES modem escape arrangement) 166 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 167 * within window time signals a "soft" exit from slip mode by remote end 168 * if the IFF_DEBUG flag is on. 169 */ 170 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 171 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 172 #define ABT_COUNT 3 /* count of escapes for abort */ 173 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 174 175 static struct sl_softc sl_softc[NSL]; 176 177 #define FRAME_END 0xc0 /* Frame End */ 178 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 179 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 180 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 181 182 static int slinit (struct sl_softc *); 183 static struct mbuf *sl_btom (struct sl_softc *, int); 184 static timeout_t sl_keepalive; 185 static timeout_t sl_outfill; 186 static int slclose (struct tty *,int); 187 static int slinput (int, struct tty *); 188 static int slioctl (struct ifnet *, u_long, caddr_t, struct ucred *); 189 static int sltioctl (struct tty *, u_long, caddr_t, int, struct ucred *); 190 static int slopen (dev_t, struct tty *); 191 static int sloutput (struct ifnet *, 192 struct mbuf *, struct sockaddr *, struct rtentry *); 193 static int slstart (struct tty *); 194 195 static struct linesw slipdisc = { 196 slopen, slclose, l_noread, l_nowrite, 197 sltioctl, slinput, slstart, ttymodem, 198 FRAME_END 199 }; 200 201 /* 202 * Called from boot code to establish sl interfaces. 203 */ 204 static void 205 slattach(void *dummy) 206 { 207 struct sl_softc *sc; 208 int i = 0; 209 210 linesw[SLIPDISC] = slipdisc; 211 212 for (sc = sl_softc; i < NSL; sc++) { 213 if_initname(&(sc->sc_if), "sl", i++); 214 sc->sc_if.if_mtu = SLMTU; 215 sc->sc_if.if_flags = 216 #ifdef SLIP_IFF_OPTS 217 SLIP_IFF_OPTS; 218 #else 219 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST; 220 #endif 221 sc->sc_if.if_type = IFT_SLIP; 222 sc->sc_if.if_ioctl = slioctl; 223 sc->sc_if.if_output = sloutput; 224 ifq_set_maxlen(&sc->sc_if.if_snd, 50); 225 ifq_set_ready(&sc->sc_if.if_snd); 226 sc->sc_fastq.ifq_maxlen = 32; 227 sc->sc_if.if_linkmib = sc; 228 sc->sc_if.if_linkmiblen = sizeof *sc; 229 callout_init(&sc->sc_oftimeout); 230 callout_init(&sc->sc_katimeout); 231 if_attach(&sc->sc_if, NULL); 232 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 233 } 234 } 235 236 static int 237 slinit(struct sl_softc *sc) 238 { 239 if (sc->sc_ep == NULL) 240 sc->sc_ep = malloc(SLBUFSIZE, M_DEVBUF, M_WAITOK); 241 sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX; 242 sc->sc_mp = sc->sc_buf; 243 sl_compress_init(&sc->sc_comp, -1); 244 return (1); 245 } 246 247 /* 248 * Line specific open routine. 249 * Attach the given tty to the first available sl unit. 250 */ 251 /* ARGSUSED */ 252 static int 253 slopen(dev_t dev, struct tty *tp) 254 { 255 struct sl_softc *sc; 256 int nsl; 257 int error; 258 struct thread *td = curthread; /* XXX */ 259 260 error = suser(td); 261 if (error) 262 return (error); 263 264 if (tp->t_line == SLIPDISC) 265 return (0); 266 267 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 268 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) { 269 if (slinit(sc) == 0) 270 return (ENOBUFS); 271 tp->t_sc = (caddr_t)sc; 272 sc->sc_ttyp = tp; 273 sc->sc_if.if_baudrate = tp->t_ospeed; 274 ttyflush(tp, FREAD | FWRITE); 275 276 tp->t_line = SLIPDISC; 277 /* 278 * We don't use t_canq or t_rawq, so reduce their 279 * cblock resources to 0. Reserve enough cblocks 280 * for t_outq to guarantee that we can fit a full 281 * packet if the SLIP_HIWAT check allows slstart() 282 * to loop. Use the same value for the cblock 283 * limit since the reserved blocks should always 284 * be enough. Reserving cblocks probably makes 285 * the CLISTRESERVE check unnecessary and wasteful. 286 */ 287 clist_alloc_cblocks(&tp->t_canq, 0, 0); 288 clist_alloc_cblocks(&tp->t_outq, 289 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 290 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 291 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 292 293 crit_enter(); 294 if_up(&sc->sc_if); 295 crit_exit(); 296 return (0); 297 } 298 return (ENXIO); 299 } 300 301 /* 302 * Line specific close routine. 303 * Detach the tty from the sl unit. 304 */ 305 static int 306 slclose(struct tty *tp, int flag) 307 { 308 struct sl_softc *sc; 309 310 ttyflush(tp, FREAD | FWRITE); 311 crit_enter(); 312 313 clist_free_cblocks(&tp->t_outq); 314 tp->t_line = 0; 315 sc = (struct sl_softc *)tp->t_sc; 316 if (sc != NULL) { 317 if (sc->sc_outfill) { 318 sc->sc_outfill = 0; 319 callout_stop(&sc->sc_oftimeout); 320 } 321 if (sc->sc_keepalive) { 322 sc->sc_keepalive = 0; 323 callout_stop(&sc->sc_katimeout); 324 } 325 if_down(&sc->sc_if); 326 sc->sc_flags &= SC_STATIC; 327 sc->sc_ttyp = NULL; 328 tp->t_sc = NULL; 329 if (sc->sc_ep) { 330 free(sc->sc_ep, M_DEVBUF); 331 sc->sc_ep = NULL; 332 } 333 sc->sc_mp = 0; 334 sc->sc_buf = 0; 335 } 336 crit_exit(); 337 return 0; 338 } 339 340 /* 341 * Line specific (tty) ioctl routine. 342 * Provide a way to get the sl unit number. 343 */ 344 /* ARGSUSED */ 345 static int 346 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 347 { 348 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc; 349 int nsl; 350 351 crit_enter(); 352 353 switch (cmd) { 354 case SLIOCGUNIT: 355 *(int *)data = sc->sc_if.if_dunit; 356 break; 357 358 case SLIOCSUNIT: 359 if (sc->sc_if.if_dunit != *(u_int *)data) { 360 for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) { 361 if ( nc->sc_if.if_dunit == *(u_int *)data 362 && nc->sc_ttyp == NULL 363 ) { 364 tmpnc = malloc(sizeof *tmpnc, M_TEMP, 365 M_WAITOK); 366 *tmpnc = *nc; 367 *nc = *sc; 368 nc->sc_if = tmpnc->sc_if; 369 tmpnc->sc_if = sc->sc_if; 370 *sc = *tmpnc; 371 free(tmpnc, M_TEMP); 372 if (sc->sc_if.if_flags & IFF_UP) { 373 if_down(&sc->sc_if); 374 if (!(nc->sc_if.if_flags & IFF_UP)) 375 if_up(&nc->sc_if); 376 } else if (nc->sc_if.if_flags & IFF_UP) 377 if_down(&nc->sc_if); 378 sc->sc_flags &= ~SC_STATIC; 379 sc->sc_flags |= (nc->sc_flags & SC_STATIC); 380 tp->t_sc = sc = nc; 381 clist_alloc_cblocks(&tp->t_outq, 382 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 383 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 384 sl_compress_init(&sc->sc_comp, -1); 385 goto slfound; 386 } 387 } 388 crit_exit(); 389 return (ENXIO); 390 } 391 slfound: 392 sc->sc_flags |= SC_STATIC; 393 break; 394 395 case SLIOCSKEEPAL: 396 sc->sc_keepalive = *(u_int *)data * hz; 397 if (sc->sc_keepalive) { 398 sc->sc_flags |= SC_KEEPALIVE; 399 callout_reset(&sc->sc_katimeout, sc->sc_keepalive, 400 sl_keepalive, sc); 401 } else { 402 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 403 callout_stop(&sc->sc_katimeout); 404 sc->sc_flags &= ~SC_KEEPALIVE; 405 } 406 } 407 break; 408 409 case SLIOCGKEEPAL: 410 *(int *)data = sc->sc_keepalive / hz; 411 break; 412 413 case SLIOCSOUTFILL: 414 sc->sc_outfill = *(u_int *)data * hz; 415 if (sc->sc_outfill) { 416 sc->sc_flags |= SC_OUTWAIT; 417 callout_reset(&sc->sc_oftimeout, sc->sc_outfill, 418 sl_outfill, sc); 419 } else { 420 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 421 callout_stop(&sc->sc_oftimeout); 422 sc->sc_flags &= ~SC_OUTWAIT; 423 } 424 } 425 break; 426 427 case SLIOCGOUTFILL: 428 *(int *)data = sc->sc_outfill / hz; 429 break; 430 431 default: 432 crit_exit(); 433 return (ENOIOCTL); 434 } 435 crit_exit(); 436 return (0); 437 } 438 439 /* 440 * Queue a packet. Start transmission if not active. 441 * Compression happens in slstart; if we do it here, IP TOS 442 * will cause us to not compress "background" packets, because 443 * ordering gets trashed. It can be done for all packets in slstart. 444 */ 445 static int 446 sloutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 447 struct rtentry *rtp) 448 { 449 struct sl_softc *sc = &sl_softc[ifp->if_dunit]; 450 struct ip *ip; 451 int error; 452 struct altq_pktattr pktattr; 453 454 ifq_classify(&ifp->if_snd, m, dst->sa_family, &pktattr); 455 456 /* 457 * `Cannot happen' (see slioctl). Someday we will extend 458 * the line protocol to support other address families. 459 */ 460 if (dst->sa_family != AF_INET) { 461 printf("%s: af%d not supported\n", sc->sc_if.if_xname, 462 dst->sa_family); 463 m_freem(m); 464 sc->sc_if.if_noproto++; 465 return (EAFNOSUPPORT); 466 } 467 468 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 469 m_freem(m); 470 return (ENETDOWN); 471 } 472 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 473 m_freem(m); 474 return (EHOSTUNREACH); 475 } 476 ip = mtod(m, struct ip *); 477 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 478 m_freem(m); 479 return (ENETRESET); /* XXX ? */ 480 } 481 482 crit_enter(); 483 484 if ((ip->ip_tos & IPTOS_LOWDELAY) && !ifq_is_enabled(&sc->sc_if.if_snd)) { 485 if (IF_QFULL(&sc->sc_fastq)) { 486 IF_DROP(&sc->sc_fastq); 487 m_freem(m); 488 error = ENOBUFS; 489 } else { 490 IF_ENQUEUE(&sc->sc_fastq, m); 491 error = 0; 492 } 493 } else { 494 error = ifq_enqueue(&sc->sc_if.if_snd, m, &pktattr); 495 } 496 if (error) { 497 sc->sc_if.if_oerrors++; 498 crit_exit(); 499 return (error); 500 } 501 if (sc->sc_ttyp->t_outq.c_cc == 0) 502 slstart(sc->sc_ttyp); 503 crit_exit(); 504 return (0); 505 } 506 507 /* 508 * Start output on interface. Get another datagram 509 * to send from the interface queue and map it to 510 * the interface before starting output. 511 */ 512 static int 513 slstart(struct tty *tp) 514 { 515 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 516 struct mbuf *m; 517 u_char *cp; 518 struct ip *ip; 519 u_char bpfbuf[SLTMAX + SLIP_HDRLEN]; 520 int len = 0; 521 522 for (;;) { 523 /* 524 * Call output process whether or not there is more in the 525 * output queue. We are being called in lieu of ttstart 526 * and must do what it would. 527 */ 528 (*tp->t_oproc)(tp); 529 530 if (tp->t_outq.c_cc != 0) { 531 if (sc != NULL) 532 sc->sc_flags &= ~SC_OUTWAIT; 533 if (tp->t_outq.c_cc > SLIP_HIWAT) 534 return 0; 535 } 536 537 /* 538 * This happens briefly when the line shuts down. 539 */ 540 if (sc == NULL) 541 return 0; 542 543 /* 544 * Get a packet and send it to the interface. 545 */ 546 crit_enter(); 547 IF_DEQUEUE(&sc->sc_fastq, m); 548 if (m) 549 sc->sc_if.if_omcasts++; /* XXX */ 550 else 551 m = ifq_dequeue(&sc->sc_if.if_snd, NULL); 552 crit_exit(); 553 if (m == NULL) 554 return 0; 555 556 /* 557 * We do the header compression here rather than in sloutput 558 * because the packets will be out of order if we are using TOS 559 * queueing, and the connection id compression will get 560 * munged when this happens. 561 */ 562 if (sc->sc_if.if_bpf) { 563 /* 564 * We need to save the TCP/IP header before it's 565 * compressed. To avoid complicated code, we just 566 * copy the entire packet into a stack buffer (since 567 * this is a serial line, packets should be short 568 * and/or the copy should be negligible cost compared 569 * to the packet transmission time). 570 */ 571 struct mbuf *m1 = m; 572 u_char *cp = bpfbuf + SLIP_HDRLEN; 573 574 len = 0; 575 do { 576 int mlen = m1->m_len; 577 578 bcopy(mtod(m1, caddr_t), cp, mlen); 579 cp += mlen; 580 len += mlen; 581 } while ((m1 = m1->m_next) != NULL); 582 } 583 ip = mtod(m, struct ip *); 584 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 585 if (sc->sc_if.if_flags & SC_COMPRESS) 586 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 587 &sc->sc_comp, 1); 588 } 589 if (sc->sc_if.if_bpf) { 590 /* 591 * Put the SLIP pseudo-"link header" in place. The 592 * compressed header is now at the beginning of the 593 * mbuf. 594 */ 595 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 596 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 597 bpf_tap(sc->sc_if.if_bpf, bpfbuf, len + SLIP_HDRLEN); 598 } 599 600 /* 601 * If system is getting low on clists, just flush our 602 * output queue (if the stuff was important, it'll get 603 * retransmitted). Note that SLTMAX is used instead of 604 * the current if_mtu setting because connections that 605 * have already been established still use the original 606 * (possibly larger) mss. 607 */ 608 if (cfreecount < CLISTRESERVE + SLTMAX) { 609 m_freem(m); 610 sc->sc_if.if_collisions++; 611 continue; 612 } 613 614 sc->sc_flags &= ~SC_OUTWAIT; 615 /* 616 * The extra FRAME_END will start up a new packet, and thus 617 * will flush any accumulated garbage. We do this whenever 618 * the line may have been idle for some time. 619 */ 620 if (tp->t_outq.c_cc == 0) { 621 ++sc->sc_if.if_obytes; 622 putc(FRAME_END, &tp->t_outq); 623 } 624 625 while (m) { 626 u_char *ep; 627 628 cp = mtod(m, u_char *); ep = cp + m->m_len; 629 while (cp < ep) { 630 /* 631 * Find out how many bytes in the string we can 632 * handle without doing something special. 633 */ 634 u_char *bp = cp; 635 636 while (cp < ep) { 637 switch (*cp++) { 638 case FRAME_ESCAPE: 639 case FRAME_END: 640 --cp; 641 goto out; 642 } 643 } 644 out: 645 if (cp > bp) { 646 /* 647 * Put n characters at once 648 * into the tty output queue. 649 */ 650 if (b_to_q((char *)bp, cp - bp, 651 &tp->t_outq)) 652 break; 653 sc->sc_if.if_obytes += cp - bp; 654 } 655 /* 656 * If there are characters left in the mbuf, 657 * the first one must be special.. 658 * Put it out in a different form. 659 */ 660 if (cp < ep) { 661 if (putc(FRAME_ESCAPE, &tp->t_outq)) 662 break; 663 if (putc(*cp++ == FRAME_ESCAPE ? 664 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 665 &tp->t_outq)) { 666 unputc(&tp->t_outq); 667 break; 668 } 669 sc->sc_if.if_obytes += 2; 670 } 671 } 672 m = m_free(m); 673 } 674 675 if (putc(FRAME_END, &tp->t_outq)) { 676 /* 677 * Not enough room. Remove a char to make room 678 * and end the packet normally. 679 * If you get many collisions (more than one or two 680 * a day) you probably do not have enough clists 681 * and you should increase "nclist" in param.c. 682 */ 683 unputc(&tp->t_outq); 684 putc(FRAME_END, &tp->t_outq); 685 sc->sc_if.if_collisions++; 686 } else { 687 ++sc->sc_if.if_obytes; 688 sc->sc_if.if_opackets++; 689 } 690 } 691 return 0; 692 } 693 694 /* 695 * Copy data buffer to mbuf chain; add ifnet pointer. 696 */ 697 static struct mbuf * 698 sl_btom(struct sl_softc *sc, int len) 699 { 700 struct mbuf *m; 701 702 if (len >= MCLBYTES) 703 return (NULL); 704 705 MGETHDR(m, MB_DONTWAIT, MT_DATA); 706 if (m == NULL) 707 return (NULL); 708 709 /* 710 * If we have more than MHLEN bytes, it's cheaper to 711 * queue the cluster we just filled & allocate a new one 712 * for the input buffer. Otherwise, fill the mbuf we 713 * allocated above. Note that code in the input routine 714 * guarantees that packet will fit in a cluster. 715 */ 716 if (len >= MHLEN) { 717 MCLGET(m, MB_DONTWAIT); 718 if ((m->m_flags & M_EXT) == 0) { 719 /* 720 * we couldn't get a cluster - if memory's this 721 * low, it's time to start dropping packets. 722 */ 723 m_free(m); 724 return (NULL); 725 } 726 } 727 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 728 m->m_len = len; 729 m->m_pkthdr.len = len; 730 m->m_pkthdr.rcvif = &sc->sc_if; 731 return (m); 732 } 733 734 /* 735 * tty interface receiver interrupt. 736 */ 737 static int 738 slinput(int c, struct tty *tp) 739 { 740 struct sl_softc *sc; 741 struct mbuf *m; 742 int len; 743 u_char chdr[CHDR_LEN]; 744 745 tk_nin++; 746 sc = (struct sl_softc *)tp->t_sc; 747 if (sc == NULL) 748 return 0; 749 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 750 sc->sc_flags |= SC_ERROR; 751 return 0; 752 } 753 c &= TTY_CHARMASK; 754 755 ++sc->sc_if.if_ibytes; 756 757 if (sc->sc_if.if_flags & IFF_DEBUG) { 758 if (c == ABT_ESC) { 759 /* 760 * If we have a previous abort, see whether 761 * this one is within the time limit. 762 */ 763 if (sc->sc_abortcount && 764 time_second >= sc->sc_starttime + ABT_WINDOW) 765 sc->sc_abortcount = 0; 766 /* 767 * If we see an abort after "idle" time, count it; 768 * record when the first abort escape arrived. 769 */ 770 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 771 if (++sc->sc_abortcount == 1) 772 sc->sc_starttime = time_second; 773 if (sc->sc_abortcount >= ABT_COUNT) { 774 slclose(tp,0); 775 return 0; 776 } 777 } 778 } else 779 sc->sc_abortcount = 0; 780 sc->sc_lasttime = time_second; 781 } 782 783 switch (c) { 784 785 case TRANS_FRAME_ESCAPE: 786 if (sc->sc_escape) 787 c = FRAME_ESCAPE; 788 break; 789 790 case TRANS_FRAME_END: 791 if (sc->sc_escape) 792 c = FRAME_END; 793 break; 794 795 case FRAME_ESCAPE: 796 sc->sc_escape = 1; 797 return 0; 798 799 case FRAME_END: 800 sc->sc_flags &= ~SC_KEEPALIVE; 801 if(sc->sc_flags & SC_ERROR) { 802 sc->sc_flags &= ~SC_ERROR; 803 goto newpack; 804 } 805 len = sc->sc_mp - sc->sc_buf; 806 if (len < 3) 807 /* less than min length packet - ignore */ 808 goto newpack; 809 810 if (sc->sc_if.if_bpf) { 811 /* 812 * Save the compressed header, so we 813 * can tack it on later. Note that we 814 * will end up copying garbage in some 815 * cases but this is okay. We remember 816 * where the buffer started so we can 817 * compute the new header length. 818 */ 819 bcopy(sc->sc_buf, chdr, CHDR_LEN); 820 } 821 822 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 823 if (c & 0x80) 824 c = TYPE_COMPRESSED_TCP; 825 else if (c == TYPE_UNCOMPRESSED_TCP) 826 *sc->sc_buf &= 0x4f; /* XXX */ 827 /* 828 * We've got something that's not an IP packet. 829 * If compression is enabled, try to decompress it. 830 * Otherwise, if `auto-enable' compression is on and 831 * it's a reasonable packet, decompress it and then 832 * enable compression. Otherwise, drop it. 833 */ 834 if (sc->sc_if.if_flags & SC_COMPRESS) { 835 len = sl_uncompress_tcp(&sc->sc_buf, len, 836 (u_int)c, &sc->sc_comp); 837 if (len <= 0) 838 goto error; 839 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 840 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 841 len = sl_uncompress_tcp(&sc->sc_buf, len, 842 (u_int)c, &sc->sc_comp); 843 if (len <= 0) 844 goto error; 845 sc->sc_if.if_flags |= SC_COMPRESS; 846 } else 847 goto error; 848 } 849 if (sc->sc_if.if_bpf) { 850 /* 851 * Put the SLIP pseudo-"link header" in place. 852 * We couldn't do this any earlier since 853 * decompression probably moved the buffer 854 * pointer. Then, invoke BPF. 855 */ 856 u_char *hp = sc->sc_buf - SLIP_HDRLEN; 857 858 hp[SLX_DIR] = SLIPDIR_IN; 859 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 860 bpf_tap(sc->sc_if.if_bpf, hp, len + SLIP_HDRLEN); 861 } 862 m = sl_btom(sc, len); 863 if (m == NULL) 864 goto error; 865 866 sc->sc_if.if_ipackets++; 867 868 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 869 m_freem(m); 870 goto newpack; 871 } 872 873 if (netisr_queue(NETISR_IP, m)) { 874 sc->sc_if.if_ierrors++; 875 sc->sc_if.if_iqdrops++; 876 } 877 878 goto newpack; 879 } 880 if (sc->sc_mp < sc->sc_ep + SLBUFSIZE) { 881 *sc->sc_mp++ = c; 882 sc->sc_escape = 0; 883 return 0; 884 } 885 886 /* can't put lower; would miss an extra frame */ 887 sc->sc_flags |= SC_ERROR; 888 889 error: 890 sc->sc_if.if_ierrors++; 891 newpack: 892 sc->sc_mp = sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX; 893 sc->sc_escape = 0; 894 return 0; 895 } 896 897 /* 898 * Process an ioctl request. 899 */ 900 static int 901 slioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 902 { 903 struct ifaddr *ifa = (struct ifaddr *)data; 904 struct ifreq *ifr = (struct ifreq *)data; 905 int error = 0; 906 907 crit_enter(); 908 909 switch (cmd) { 910 911 case SIOCSIFFLAGS: 912 /* 913 * if.c will set the interface up even if we 914 * don't want it to. 915 */ 916 if (sl_softc[ifp->if_dunit].sc_ttyp == NULL) { 917 ifp->if_flags &= ~IFF_UP; 918 } 919 break; 920 case SIOCSIFADDR: 921 /* 922 * This is "historical" - set the interface up when 923 * setting the address. 924 */ 925 if (ifa->ifa_addr->sa_family == AF_INET) { 926 if (sl_softc[ifp->if_dunit].sc_ttyp != NULL) 927 ifp->if_flags |= IFF_UP; 928 } else { 929 error = EAFNOSUPPORT; 930 } 931 break; 932 933 case SIOCSIFDSTADDR: 934 if (ifa->ifa_addr->sa_family != AF_INET) 935 error = EAFNOSUPPORT; 936 break; 937 938 case SIOCADDMULTI: 939 case SIOCDELMULTI: 940 break; 941 942 case SIOCSIFMTU: 943 /* 944 * Set the interface MTU. 945 */ 946 if (ifr->ifr_mtu > SLTMAX) 947 error = EINVAL; 948 else { 949 struct tty *tp; 950 951 ifp->if_mtu = ifr->ifr_mtu; 952 tp = sl_softc[ifp->if_dunit].sc_ttyp; 953 if (tp != NULL) 954 clist_alloc_cblocks(&tp->t_outq, 955 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 956 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 957 } 958 break; 959 960 default: 961 error = EINVAL; 962 } 963 964 crit_exit(); 965 return (error); 966 } 967 968 static void 969 sl_keepalive(void *chan) 970 { 971 struct sl_softc *sc = chan; 972 973 if (sc->sc_keepalive) { 974 if (sc->sc_flags & SC_KEEPALIVE) 975 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 976 else 977 sc->sc_flags |= SC_KEEPALIVE; 978 callout_reset(&sc->sc_katimeout, sc->sc_keepalive, 979 sl_keepalive, sc); 980 } else { 981 sc->sc_flags &= ~SC_KEEPALIVE; 982 } 983 } 984 985 static void 986 sl_outfill(void *chan) 987 { 988 struct sl_softc *sc = chan; 989 struct tty *tp = sc->sc_ttyp; 990 991 if (sc->sc_outfill && tp != NULL) { 992 if (sc->sc_flags & SC_OUTWAIT) { 993 crit_enter(); 994 ++sc->sc_if.if_obytes; 995 putc(FRAME_END, &tp->t_outq); 996 (*tp->t_oproc)(tp); 997 crit_exit(); 998 } else 999 sc->sc_flags |= SC_OUTWAIT; 1000 callout_reset(&sc->sc_oftimeout, sc->sc_outfill, 1001 sl_outfill, sc); 1002 } else { 1003 sc->sc_flags &= ~SC_OUTWAIT; 1004 } 1005 } 1006