1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1987, 1989, 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)if_sl.c 8.6 (Berkeley) 2/1/94 36 * $FreeBSD: src/sys/net/if_sl.c,v 1.84.2.2 2002/02/13 00:43:10 dillon Exp $ 37 * $DragonFly: src/sys/net/sl/if_sl.c,v 1.32 2008/05/14 11:59:23 sephe Exp $ 38 */ 39 40 /* 41 * Serial Line interface 42 * 43 * Rick Adams 44 * Center for Seismic Studies 45 * 1300 N 17th Street, Suite 1450 46 * Arlington, Virginia 22209 47 * (703)276-7900 48 * rick@seismo.ARPA 49 * seismo!rick 50 * 51 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). 52 * N.B.: this belongs in netinet, not net, the way it stands now. 53 * Should have a link-layer type designation, but wouldn't be 54 * backwards-compatible. 55 * 56 * Converted to 4.3BSD Beta by Chris Torek. 57 * Other changes made at Berkeley, based in part on code by Kirk Smith. 58 * W. Jolitz added slip abort. 59 * 60 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov). 61 * Added priority queuing for "interactive" traffic; hooks for TCP 62 * header compression; ICMP filtering (at 2400 baud, some cretin 63 * pinging you can use up all your bandwidth). Made low clist behavior 64 * more robust and slightly less likely to hang serial line. 65 * Sped up a bunch of things. 66 */ 67 68 #include "use_sl.h" 69 70 #include "opt_inet.h" 71 #if !defined(KLD_MODULE) 72 #include "opt_slip.h" 73 #endif 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/proc.h> 77 #include <sys/priv.h> 78 #include <sys/malloc.h> 79 #include <sys/mbuf.h> 80 #include <sys/dkstat.h> 81 #include <sys/socket.h> 82 #include <sys/sockio.h> 83 #include <sys/fcntl.h> 84 #include <sys/signalvar.h> 85 #include <sys/tty.h> 86 #include <sys/clist.h> 87 #include <sys/kernel.h> 88 #include <sys/conf.h> 89 #include <sys/thread2.h> 90 91 #include <net/if.h> 92 #include <net/if_types.h> 93 #include <net/ifq_var.h> 94 #include <net/netisr.h> 95 96 #if INET 97 #include <netinet/in.h> 98 #include <netinet/in_systm.h> 99 #include <netinet/in_var.h> 100 #include <netinet/ip.h> 101 #else 102 #error "Huh? Slip without inet?" 103 #endif 104 105 #include <net/slcompress.h> 106 #include "if_slvar.h" 107 #include <net/slip.h> 108 109 #include <net/bpf.h> 110 111 static void slattach (void *); 112 PSEUDO_SET(slattach, if_sl); 113 114 /* 115 * SLRMAX is a hard limit on input packet size. To simplify the code 116 * and improve performance, we require that packets fit in an mbuf 117 * cluster, and if we get a compressed packet, there's enough extra 118 * room to expand the header into a max length tcp/ip header (128 119 * bytes). So, SLRMAX can be at most 120 * MCLBYTES - 128 121 * 122 * SLMTU is the default transmit MTU. The transmit MTU should be kept 123 * small enough so that interactive use doesn't suffer, but large 124 * enough to provide good performance. 552 is a good choice for SLMTU 125 * because it is high enough to not fragment TCP packets being routed 126 * through this host. Packet fragmentation is bad with SLIP because 127 * fragment headers aren't compressed. The previous assumptions about 128 * the best MTU value don't really hold when using modern modems with 129 * BTLZ data compression because the modem buffers play a much larger 130 * role in interactive performance than the MTU. The MTU can be changed 131 * at any time to suit the specific environment with ifconfig(8), and 132 * its maximum value is defined as SLTMAX. SLTMAX must not be so large 133 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c 134 * handles this better). 135 * 136 * SLIP_HIWAT is the amount of data that will be queued 'downstream' 137 * of us (i.e., in clists waiting to be picked up by the tty output 138 * interrupt). If we queue a lot of data downstream, it's immune to 139 * our t.o.s. queuing. 140 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed 141 * telnet/ftp will see a 1 sec wait, independent of the mtu (the 142 * wait is dependent on the ftp window size but that's typically 143 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize 144 * the cost (in idle time on the wire) of the tty driver running 145 * off the end of its clists & having to call back slstart for a 146 * new packet. For a tty interface with any buffering at all, this 147 * cost will be zero. Even with a totally brain dead interface (like 148 * the one on a typical workstation), the cost will be <= 1 character 149 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose 150 * at most 1% while maintaining good interactive response. 151 */ 152 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN) 153 #define SLRMAX (MCLBYTES - BUFOFFSET) 154 #define SLBUFSIZE (SLRMAX + BUFOFFSET) 155 #ifndef SLMTU 156 #define SLMTU 552 /* default MTU */ 157 #endif 158 #define SLTMAX 1500 /* maximum MTU */ 159 #define SLIP_HIWAT roundup(50,CBSIZE) 160 #define CLISTRESERVE 1024 /* Can't let clists get too low */ 161 162 /* 163 * SLIP ABORT ESCAPE MECHANISM: 164 * (inspired by HAYES modem escape arrangement) 165 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape } 166 * within window time signals a "soft" exit from slip mode by remote end 167 * if the IFF_DEBUG flag is on. 168 */ 169 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/ 170 #define ABT_IDLE 1 /* in seconds - idle before an escape */ 171 #define ABT_COUNT 3 /* count of escapes for abort */ 172 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */ 173 174 static struct sl_softc sl_softc[NSL]; 175 176 #define FRAME_END 0xc0 /* Frame End */ 177 #define FRAME_ESCAPE 0xdb /* Frame Esc */ 178 #define TRANS_FRAME_END 0xdc /* transposed frame end */ 179 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */ 180 181 static int slinit (struct sl_softc *); 182 static struct mbuf *sl_btom (struct sl_softc *, int); 183 static timeout_t sl_keepalive; 184 static timeout_t sl_outfill; 185 static int slclose (struct tty *,int); 186 static int slinput (int, struct tty *); 187 static int slioctl (struct ifnet *, u_long, caddr_t, struct ucred *); 188 static int sltioctl (struct tty *, u_long, caddr_t, int, struct ucred *); 189 static int slopen (cdev_t, struct tty *); 190 static int sloutput (struct ifnet *, 191 struct mbuf *, struct sockaddr *, struct rtentry *); 192 static int slstart (struct tty *); 193 194 static struct linesw slipdisc = { 195 slopen, slclose, l_noread, l_nowrite, 196 sltioctl, slinput, slstart, ttymodem, 197 FRAME_END 198 }; 199 200 /* 201 * Called from boot code to establish sl interfaces. 202 */ 203 static void 204 slattach(void *dummy) 205 { 206 struct sl_softc *sc; 207 int i = 0; 208 209 lwkt_gettoken(&tty_token); 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_mp(&sc->sc_oftimeout); 230 callout_init_mp(&sc->sc_katimeout); 231 if_attach(&sc->sc_if, NULL); 232 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN); 233 } 234 lwkt_reltoken(&tty_token); 235 } 236 237 static int 238 slinit(struct sl_softc *sc) 239 { 240 lwkt_gettoken(&tty_token); 241 if (sc->sc_ep == NULL) 242 sc->sc_ep = kmalloc(SLBUFSIZE, M_DEVBUF, M_WAITOK); 243 sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX; 244 sc->sc_mp = sc->sc_buf; 245 sl_compress_init(&sc->sc_comp, -1); 246 lwkt_reltoken(&tty_token); 247 return (1); 248 } 249 250 /* 251 * Line specific open routine. 252 * Attach the given tty to the first available sl unit. 253 */ 254 /* ARGSUSED */ 255 static int 256 slopen(cdev_t dev, struct tty *tp) 257 { 258 struct sl_softc *sc; 259 int nsl; 260 int error; 261 struct thread *td = curthread; /* XXX */ 262 263 error = priv_check(td, PRIV_ROOT); 264 if (error) 265 return (error); 266 267 lwkt_gettoken(&tty_token); 268 if (tp->t_line == SLIPDISC) { 269 lwkt_reltoken(&tty_token); 270 return (0); 271 } 272 273 for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) 274 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) { 275 if (slinit(sc) == 0) { 276 lwkt_reltoken(&tty_token); 277 return (ENOBUFS); 278 } 279 tp->t_sc = (caddr_t)sc; 280 sc->sc_ttyp = tp; 281 sc->sc_if.if_baudrate = tp->t_ospeed; 282 ttyflush(tp, FREAD | FWRITE); 283 284 tp->t_line = SLIPDISC; 285 /* 286 * We don't use t_canq or t_rawq, so reduce their 287 * cblock resources to 0. Reserve enough cblocks 288 * for t_outq to guarantee that we can fit a full 289 * packet if the SLIP_HIWAT check allows slstart() 290 * to loop. Use the same value for the cblock 291 * limit since the reserved blocks should always 292 * be enough. Reserving cblocks probably makes 293 * the CLISTRESERVE check unnecessary and wasteful. 294 */ 295 clist_alloc_cblocks(&tp->t_canq, 0, 0); 296 clist_alloc_cblocks(&tp->t_outq, 297 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 298 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 299 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 300 301 crit_enter(); 302 if_up(&sc->sc_if); 303 crit_exit(); 304 lwkt_reltoken(&tty_token); 305 return (0); 306 } 307 lwkt_reltoken(&tty_token); 308 return (ENXIO); 309 } 310 311 /* 312 * Line specific close routine. 313 * Detach the tty from the sl unit. 314 */ 315 static int 316 slclose(struct tty *tp, int flag) 317 { 318 struct sl_softc *sc; 319 320 lwkt_gettoken(&tty_token); 321 ttyflush(tp, FREAD | FWRITE); 322 crit_enter(); 323 324 clist_free_cblocks(&tp->t_outq); 325 tp->t_line = 0; 326 sc = (struct sl_softc *)tp->t_sc; 327 if (sc != NULL) { 328 if (sc->sc_outfill) { 329 sc->sc_outfill = 0; 330 callout_stop(&sc->sc_oftimeout); 331 } 332 if (sc->sc_keepalive) { 333 sc->sc_keepalive = 0; 334 callout_stop(&sc->sc_katimeout); 335 } 336 if_down(&sc->sc_if); 337 sc->sc_flags &= SC_STATIC; 338 sc->sc_ttyp = NULL; 339 tp->t_sc = NULL; 340 if (sc->sc_ep) { 341 kfree(sc->sc_ep, M_DEVBUF); 342 sc->sc_ep = NULL; 343 } 344 sc->sc_mp = 0; 345 sc->sc_buf = 0; 346 } 347 crit_exit(); 348 lwkt_reltoken(&tty_token); 349 return 0; 350 } 351 352 /* 353 * Line specific (tty) ioctl routine. 354 * Provide a way to get the sl unit number. 355 */ 356 /* ARGSUSED */ 357 static int 358 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 359 { 360 struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc; 361 int nsl; 362 363 crit_enter(); 364 lwkt_gettoken(&tty_token); 365 366 switch (cmd) { 367 case SLIOCGUNIT: 368 *(int *)data = sc->sc_if.if_dunit; 369 break; 370 371 case SLIOCSUNIT: 372 if (sc->sc_if.if_dunit != *(u_int *)data) { 373 for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) { 374 if ( nc->sc_if.if_dunit == *(u_int *)data 375 && nc->sc_ttyp == NULL 376 ) { 377 tmpnc = kmalloc(sizeof *tmpnc, M_TEMP, 378 M_WAITOK); 379 *tmpnc = *nc; 380 *nc = *sc; 381 nc->sc_if = tmpnc->sc_if; 382 tmpnc->sc_if = sc->sc_if; 383 *sc = *tmpnc; 384 kfree(tmpnc, M_TEMP); 385 if (sc->sc_if.if_flags & IFF_UP) { 386 if_down(&sc->sc_if); 387 if (!(nc->sc_if.if_flags & IFF_UP)) 388 if_up(&nc->sc_if); 389 } else if (nc->sc_if.if_flags & IFF_UP) 390 if_down(&nc->sc_if); 391 sc->sc_flags &= ~SC_STATIC; 392 sc->sc_flags |= (nc->sc_flags & SC_STATIC); 393 tp->t_sc = sc = nc; 394 clist_alloc_cblocks(&tp->t_outq, 395 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1, 396 SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1); 397 sl_compress_init(&sc->sc_comp, -1); 398 goto slfound; 399 } 400 } 401 lwkt_reltoken(&tty_token); 402 crit_exit(); 403 return (ENXIO); 404 } 405 slfound: 406 sc->sc_flags |= SC_STATIC; 407 break; 408 409 case SLIOCSKEEPAL: 410 sc->sc_keepalive = *(u_int *)data * hz; 411 if (sc->sc_keepalive) { 412 sc->sc_flags |= SC_KEEPALIVE; 413 callout_reset(&sc->sc_katimeout, sc->sc_keepalive, 414 sl_keepalive, sc); 415 } else { 416 if ((sc->sc_flags & SC_KEEPALIVE) != 0) { 417 callout_stop(&sc->sc_katimeout); 418 sc->sc_flags &= ~SC_KEEPALIVE; 419 } 420 } 421 break; 422 423 case SLIOCGKEEPAL: 424 *(int *)data = sc->sc_keepalive / hz; 425 break; 426 427 case SLIOCSOUTFILL: 428 sc->sc_outfill = *(u_int *)data * hz; 429 if (sc->sc_outfill) { 430 sc->sc_flags |= SC_OUTWAIT; 431 callout_reset(&sc->sc_oftimeout, sc->sc_outfill, 432 sl_outfill, sc); 433 } else { 434 if ((sc->sc_flags & SC_OUTWAIT) != 0) { 435 callout_stop(&sc->sc_oftimeout); 436 sc->sc_flags &= ~SC_OUTWAIT; 437 } 438 } 439 break; 440 441 case SLIOCGOUTFILL: 442 *(int *)data = sc->sc_outfill / hz; 443 break; 444 445 default: 446 lwkt_reltoken(&tty_token); 447 crit_exit(); 448 return (ENOIOCTL); 449 } 450 lwkt_reltoken(&tty_token); 451 crit_exit(); 452 return (0); 453 } 454 455 /* 456 * Queue a packet. Start transmission if not active. 457 * Compression happens in slstart; if we do it here, IP TOS 458 * will cause us to not compress "background" packets, because 459 * ordering gets trashed. It can be done for all packets in slstart. 460 */ 461 static int 462 sloutput_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 463 struct rtentry *rtp) 464 { 465 struct sl_softc *sc = &sl_softc[ifp->if_dunit]; 466 struct ip *ip; 467 int error; 468 struct altq_pktattr pktattr; 469 470 ifq_classify(&ifp->if_snd, m, dst->sa_family, &pktattr); 471 472 /* 473 * `Cannot happen' (see slioctl). Someday we will extend 474 * the line protocol to support other address families. 475 */ 476 if (dst->sa_family != AF_INET) { 477 kprintf("%s: af%d not supported\n", sc->sc_if.if_xname, 478 dst->sa_family); 479 m_freem(m); 480 sc->sc_if.if_noproto++; 481 return (EAFNOSUPPORT); 482 } 483 484 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) { 485 m_freem(m); 486 return (ENETDOWN); 487 } 488 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) { 489 m_freem(m); 490 return (EHOSTUNREACH); 491 } 492 ip = mtod(m, struct ip *); 493 if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) { 494 m_freem(m); 495 return (ENETRESET); /* XXX ? */ 496 } 497 498 crit_enter(); 499 500 if ((ip->ip_tos & IPTOS_LOWDELAY) && !ifq_is_enabled(&sc->sc_if.if_snd)) { 501 if (IF_QFULL(&sc->sc_fastq)) { 502 IF_DROP(&sc->sc_fastq); 503 m_freem(m); 504 error = ENOBUFS; 505 } else { 506 IF_ENQUEUE(&sc->sc_fastq, m); 507 error = 0; 508 } 509 } else { 510 error = ifq_enqueue(&sc->sc_if.if_snd, m, &pktattr); 511 } 512 if (error) { 513 sc->sc_if.if_oerrors++; 514 crit_exit(); 515 return (error); 516 } 517 if (sc->sc_ttyp->t_outq.c_cc == 0) 518 slstart(sc->sc_ttyp); 519 crit_exit(); 520 return (0); 521 } 522 523 static int 524 sloutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 525 struct rtentry *rtp) 526 { 527 int error; 528 529 ifnet_serialize_tx(ifp); 530 error = sloutput_serialized(ifp, m, dst, rtp); 531 ifnet_deserialize_tx(ifp); 532 533 return error; 534 } 535 536 /* 537 * Start output on interface. Get another datagram 538 * to send from the interface queue and map it to 539 * the interface before starting output. 540 */ 541 static int 542 slstart(struct tty *tp) 543 { 544 struct sl_softc *sc = (struct sl_softc *)tp->t_sc; 545 struct mbuf *m; 546 u_char *cp; 547 struct ip *ip; 548 u_char bpfbuf[SLTMAX + SLIP_HDRLEN]; 549 int len = 0; 550 551 lwkt_gettoken(&tty_token); 552 for (;;) { 553 /* 554 * Call output process whether or not there is more in the 555 * output queue. We are being called in lieu of ttstart 556 * and must do what it would. 557 */ 558 (*tp->t_oproc)(tp); 559 560 if (tp->t_outq.c_cc != 0) { 561 if (sc != NULL) 562 sc->sc_flags &= ~SC_OUTWAIT; 563 if (tp->t_outq.c_cc > SLIP_HIWAT) { 564 lwkt_reltoken(&tty_token); 565 return 0; 566 } 567 } 568 569 /* 570 * This happens briefly when the line shuts down. 571 */ 572 if (sc == NULL) { 573 lwkt_reltoken(&tty_token); 574 return 0; 575 } 576 577 /* 578 * Get a packet and send it to the interface. 579 */ 580 crit_enter(); 581 IF_DEQUEUE(&sc->sc_fastq, m); 582 if (m) 583 sc->sc_if.if_omcasts++; /* XXX */ 584 else 585 m = ifq_dequeue(&sc->sc_if.if_snd, NULL); 586 crit_exit(); 587 if (m == NULL) { 588 lwkt_reltoken(&tty_token); 589 return 0; 590 } 591 592 /* 593 * We do the header compression here rather than in sloutput 594 * because the packets will be out of order if we are using TOS 595 * queueing, and the connection id compression will get 596 * munged when this happens. 597 */ 598 if (sc->sc_if.if_bpf) { 599 /* 600 * We need to save the TCP/IP header before it's 601 * compressed. To avoid complicated code, we just 602 * copy the entire packet into a stack buffer (since 603 * this is a serial line, packets should be short 604 * and/or the copy should be negligible cost compared 605 * to the packet transmission time). 606 */ 607 struct mbuf *m1 = m; 608 u_char *cp = bpfbuf + SLIP_HDRLEN; 609 610 len = 0; 611 do { 612 int mlen = m1->m_len; 613 614 bcopy(mtod(m1, caddr_t), cp, mlen); 615 cp += mlen; 616 len += mlen; 617 } while ((m1 = m1->m_next) != NULL); 618 } 619 ip = mtod(m, struct ip *); 620 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) { 621 if (sc->sc_if.if_flags & SC_COMPRESS) 622 *mtod(m, u_char *) |= sl_compress_tcp(m, ip, 623 &sc->sc_comp, 1); 624 } 625 if (sc->sc_if.if_bpf) { 626 /* 627 * Put the SLIP pseudo-"link header" in place. The 628 * compressed header is now at the beginning of the 629 * mbuf. 630 */ 631 bpfbuf[SLX_DIR] = SLIPDIR_OUT; 632 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN); 633 bpf_tap(sc->sc_if.if_bpf, bpfbuf, len + SLIP_HDRLEN); 634 } 635 636 /* 637 * If system is getting low on clists, just flush our 638 * output queue (if the stuff was important, it'll get 639 * retransmitted). Note that SLTMAX is used instead of 640 * the current if_mtu setting because connections that 641 * have already been established still use the original 642 * (possibly larger) mss. 643 */ 644 if (cfreecount < CLISTRESERVE + SLTMAX) { 645 m_freem(m); 646 sc->sc_if.if_collisions++; 647 continue; 648 } 649 650 sc->sc_flags &= ~SC_OUTWAIT; 651 /* 652 * The extra FRAME_END will start up a new packet, and thus 653 * will flush any accumulated garbage. We do this whenever 654 * the line may have been idle for some time. 655 */ 656 if (tp->t_outq.c_cc == 0) { 657 ++sc->sc_if.if_obytes; 658 clist_putc(FRAME_END, &tp->t_outq); 659 } 660 661 while (m) { 662 u_char *ep; 663 664 cp = mtod(m, u_char *); ep = cp + m->m_len; 665 while (cp < ep) { 666 /* 667 * Find out how many bytes in the string we can 668 * handle without doing something special. 669 */ 670 u_char *bp = cp; 671 672 while (cp < ep) { 673 switch (*cp++) { 674 case FRAME_ESCAPE: 675 case FRAME_END: 676 --cp; 677 goto out; 678 } 679 } 680 out: 681 if (cp > bp) { 682 /* 683 * Put n characters at once 684 * into the tty output queue. 685 */ 686 if (b_to_q((char *)bp, cp - bp, 687 &tp->t_outq)) 688 break; 689 sc->sc_if.if_obytes += cp - bp; 690 } 691 /* 692 * If there are characters left in the mbuf, 693 * the first one must be special.. 694 * Put it out in a different form. 695 */ 696 if (cp < ep) { 697 if (clist_putc(FRAME_ESCAPE, &tp->t_outq)) 698 break; 699 if (clist_putc(*cp++ == FRAME_ESCAPE ? 700 TRANS_FRAME_ESCAPE : TRANS_FRAME_END, 701 &tp->t_outq)) { 702 clist_unputc(&tp->t_outq); 703 break; 704 } 705 sc->sc_if.if_obytes += 2; 706 } 707 } 708 m = m_free(m); 709 } 710 711 if (clist_putc(FRAME_END, &tp->t_outq)) { 712 /* 713 * Not enough room. Remove a char to make room 714 * and end the packet normally. 715 * If you get many collisions (more than one or two 716 * a day) you probably do not have enough clists 717 * and you should increase "nclist" in param.c. 718 */ 719 clist_unputc(&tp->t_outq); 720 clist_putc(FRAME_END, &tp->t_outq); 721 sc->sc_if.if_collisions++; 722 } else { 723 ++sc->sc_if.if_obytes; 724 sc->sc_if.if_opackets++; 725 } 726 } 727 lwkt_reltoken(&tty_token); 728 return 0; 729 } 730 731 /* 732 * Copy data buffer to mbuf chain; add ifnet pointer. 733 */ 734 static struct mbuf * 735 sl_btom(struct sl_softc *sc, int len) 736 { 737 struct mbuf *m; 738 739 if (len >= MCLBYTES) 740 return (NULL); 741 742 MGETHDR(m, MB_DONTWAIT, MT_DATA); 743 if (m == NULL) 744 return (NULL); 745 746 /* 747 * If we have more than MHLEN bytes, it's cheaper to 748 * queue the cluster we just filled & allocate a new one 749 * for the input buffer. Otherwise, fill the mbuf we 750 * allocated above. Note that code in the input routine 751 * guarantees that packet will fit in a cluster. 752 */ 753 if (len >= MHLEN) { 754 MCLGET(m, MB_DONTWAIT); 755 if ((m->m_flags & M_EXT) == 0) { 756 /* 757 * we couldn't get a cluster - if memory's this 758 * low, it's time to start dropping packets. 759 */ 760 m_free(m); 761 return (NULL); 762 } 763 } 764 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len); 765 m->m_len = len; 766 m->m_pkthdr.len = len; 767 m->m_pkthdr.rcvif = &sc->sc_if; 768 return (m); 769 } 770 771 /* 772 * tty interface receiver interrupt. 773 */ 774 static int 775 slinput(int c, struct tty *tp) 776 { 777 struct sl_softc *sc; 778 struct mbuf *m; 779 int len; 780 u_char chdr[CHDR_LEN]; 781 782 lwkt_gettoken(&tty_token); 783 tk_nin++; 784 sc = (struct sl_softc *)tp->t_sc; 785 if (sc == NULL) { 786 lwkt_reltoken(&tty_token); 787 return 0; 788 } 789 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) { 790 sc->sc_flags |= SC_ERROR; 791 lwkt_reltoken(&tty_token); 792 return 0; 793 } 794 c &= TTY_CHARMASK; 795 796 ++sc->sc_if.if_ibytes; 797 798 if (sc->sc_if.if_flags & IFF_DEBUG) { 799 if (c == ABT_ESC) { 800 /* 801 * If we have a previous abort, see whether 802 * this one is within the time limit. 803 */ 804 if (sc->sc_abortcount && 805 time_second >= sc->sc_starttime + ABT_WINDOW) 806 sc->sc_abortcount = 0; 807 /* 808 * If we see an abort after "idle" time, count it; 809 * record when the first abort escape arrived. 810 */ 811 if (time_second >= sc->sc_lasttime + ABT_IDLE) { 812 if (++sc->sc_abortcount == 1) 813 sc->sc_starttime = time_second; 814 if (sc->sc_abortcount >= ABT_COUNT) { 815 slclose(tp,0); 816 lwkt_reltoken(&tty_token); 817 return 0; 818 } 819 } 820 } else 821 sc->sc_abortcount = 0; 822 sc->sc_lasttime = time_second; 823 } 824 825 switch (c) { 826 827 case TRANS_FRAME_ESCAPE: 828 if (sc->sc_escape) 829 c = FRAME_ESCAPE; 830 break; 831 832 case TRANS_FRAME_END: 833 if (sc->sc_escape) 834 c = FRAME_END; 835 break; 836 837 case FRAME_ESCAPE: 838 sc->sc_escape = 1; 839 lwkt_reltoken(&tty_token); 840 return 0; 841 842 case FRAME_END: 843 sc->sc_flags &= ~SC_KEEPALIVE; 844 if(sc->sc_flags & SC_ERROR) { 845 sc->sc_flags &= ~SC_ERROR; 846 goto newpack; 847 } 848 len = sc->sc_mp - sc->sc_buf; 849 if (len < 3) 850 /* less than min length packet - ignore */ 851 goto newpack; 852 853 if (sc->sc_if.if_bpf) { 854 /* 855 * Save the compressed header, so we 856 * can tack it on later. Note that we 857 * will end up copying garbage in some 858 * cases but this is okay. We remember 859 * where the buffer started so we can 860 * compute the new header length. 861 */ 862 bcopy(sc->sc_buf, chdr, CHDR_LEN); 863 } 864 865 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) { 866 if (c & 0x80) 867 c = TYPE_COMPRESSED_TCP; 868 else if (c == TYPE_UNCOMPRESSED_TCP) 869 *sc->sc_buf &= 0x4f; /* XXX */ 870 /* 871 * We've got something that's not an IP packet. 872 * If compression is enabled, try to decompress it. 873 * Otherwise, if `auto-enable' compression is on and 874 * it's a reasonable packet, decompress it and then 875 * enable compression. Otherwise, drop it. 876 */ 877 if (sc->sc_if.if_flags & SC_COMPRESS) { 878 len = sl_uncompress_tcp(&sc->sc_buf, len, 879 (u_int)c, &sc->sc_comp); 880 if (len <= 0) 881 goto error; 882 } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) && 883 c == TYPE_UNCOMPRESSED_TCP && len >= 40) { 884 len = sl_uncompress_tcp(&sc->sc_buf, len, 885 (u_int)c, &sc->sc_comp); 886 if (len <= 0) 887 goto error; 888 sc->sc_if.if_flags |= SC_COMPRESS; 889 } else 890 goto error; 891 } 892 if (sc->sc_if.if_bpf) { 893 /* 894 * Put the SLIP pseudo-"link header" in place. 895 * We couldn't do this any earlier since 896 * decompression probably moved the buffer 897 * pointer. Then, invoke BPF. 898 */ 899 u_char *hp = sc->sc_buf - SLIP_HDRLEN; 900 901 hp[SLX_DIR] = SLIPDIR_IN; 902 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN); 903 bpf_tap(sc->sc_if.if_bpf, hp, len + SLIP_HDRLEN); 904 } 905 m = sl_btom(sc, len); 906 if (m == NULL) 907 goto error; 908 909 sc->sc_if.if_ipackets++; 910 911 if ((sc->sc_if.if_flags & IFF_UP) == 0) { 912 m_freem(m); 913 goto newpack; 914 } 915 916 if (netisr_queue(NETISR_IP, m)) { 917 sc->sc_if.if_ierrors++; 918 sc->sc_if.if_iqdrops++; 919 } 920 921 goto newpack; 922 } 923 if (sc->sc_mp < sc->sc_ep + SLBUFSIZE) { 924 *sc->sc_mp++ = c; 925 sc->sc_escape = 0; 926 lwkt_reltoken(&tty_token); 927 return 0; 928 } 929 930 /* can't put lower; would miss an extra frame */ 931 sc->sc_flags |= SC_ERROR; 932 933 error: 934 sc->sc_if.if_ierrors++; 935 newpack: 936 sc->sc_mp = sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX; 937 sc->sc_escape = 0; 938 lwkt_reltoken(&tty_token); 939 return 0; 940 } 941 942 /* 943 * Process an ioctl request. 944 */ 945 static int 946 slioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 947 { 948 struct ifaddr *ifa = (struct ifaddr *)data; 949 struct ifreq *ifr = (struct ifreq *)data; 950 int error = 0; 951 952 crit_enter(); 953 954 switch (cmd) { 955 956 case SIOCSIFFLAGS: 957 /* 958 * if.c will set the interface up even if we 959 * don't want it to. 960 */ 961 if (sl_softc[ifp->if_dunit].sc_ttyp == NULL) { 962 ifp->if_flags &= ~IFF_UP; 963 } 964 break; 965 case SIOCSIFADDR: 966 /* 967 * This is "historical" - set the interface up when 968 * setting the address. 969 */ 970 if (ifa->ifa_addr->sa_family == AF_INET) { 971 if (sl_softc[ifp->if_dunit].sc_ttyp != NULL) 972 ifp->if_flags |= IFF_UP; 973 } else { 974 error = EAFNOSUPPORT; 975 } 976 break; 977 978 case SIOCSIFDSTADDR: 979 if (ifa->ifa_addr->sa_family != AF_INET) 980 error = EAFNOSUPPORT; 981 break; 982 983 case SIOCADDMULTI: 984 case SIOCDELMULTI: 985 break; 986 987 case SIOCSIFMTU: 988 /* 989 * Set the interface MTU. 990 */ 991 if (ifr->ifr_mtu > SLTMAX) 992 error = EINVAL; 993 else { 994 struct tty *tp; 995 996 ifp->if_mtu = ifr->ifr_mtu; 997 tp = sl_softc[ifp->if_dunit].sc_ttyp; 998 if (tp != NULL) 999 clist_alloc_cblocks(&tp->t_outq, 1000 SLIP_HIWAT + 2 * ifp->if_mtu + 1, 1001 SLIP_HIWAT + 2 * ifp->if_mtu + 1); 1002 } 1003 break; 1004 1005 default: 1006 error = EINVAL; 1007 } 1008 1009 crit_exit(); 1010 return (error); 1011 } 1012 1013 static void 1014 sl_keepalive(void *chan) 1015 { 1016 struct sl_softc *sc = chan; 1017 1018 lwkt_gettoken(&tty_token); 1019 lwkt_gettoken(&proc_token); 1020 if (sc->sc_keepalive) { 1021 if (sc->sc_flags & SC_KEEPALIVE) 1022 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1); 1023 else 1024 sc->sc_flags |= SC_KEEPALIVE; 1025 callout_reset(&sc->sc_katimeout, sc->sc_keepalive, 1026 sl_keepalive, sc); 1027 } else { 1028 sc->sc_flags &= ~SC_KEEPALIVE; 1029 } 1030 lwkt_reltoken(&proc_token); 1031 lwkt_reltoken(&tty_token); 1032 } 1033 1034 static void 1035 sl_outfill(void *chan) 1036 { 1037 struct sl_softc *sc = chan; 1038 struct tty *tp = sc->sc_ttyp; 1039 1040 lwkt_gettoken(&tty_token); 1041 1042 if (sc->sc_outfill && tp != NULL) { 1043 if (sc->sc_flags & SC_OUTWAIT) { 1044 crit_enter(); 1045 ++sc->sc_if.if_obytes; 1046 clist_putc(FRAME_END, &tp->t_outq); 1047 (*tp->t_oproc)(tp); 1048 crit_exit(); 1049 } else 1050 sc->sc_flags |= SC_OUTWAIT; 1051 callout_reset(&sc->sc_oftimeout, sc->sc_outfill, 1052 sl_outfill, sc); 1053 } else { 1054 sc->sc_flags &= ~SC_OUTWAIT; 1055 } 1056 lwkt_reltoken(&tty_token); 1057 } 1058