sys/net/sl/if_sl.c

   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 1.2 2003/06/17 04:28:48 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  * Note that splimp() is used throughout to block both (tty) input
  66  * interrupts and network activity; thus, splimp must be >= spltty.
  67  */
  68
  69 #include "sl.h"
  70
  71 #include "opt_inet.h"
  72 #if !defined(KLD_MODULE)
  73 #include "opt_slip.h"
  74 #endif
  75 #include <sys/param.h>
  76 #include <sys/systm.h>
  77 #include <sys/proc.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
  90 #include <net/if.h>
  91 #include <net/if_types.h>
  92 #include <net/netisr.h>
  93
  94 #if INET
  95 #include <netinet/in.h>
  96 #include <netinet/in_systm.h>
  97 #include <netinet/in_var.h>
  98 #include <netinet/ip.h>
  99 #else
 100 #error "Huh? Slip without inet?"
 101 #endif
 102
 103 #include <net/slcompress.h>
 104 #include <net/if_slvar.h>
 105 #include <net/slip.h>
 106
 107 #include <net/bpf.h>
 108
 109 #ifdef __i386__
 110 #include <i386/isa/intr_machdep.h>
 111 #endif
 112
 113 static void slattach __P((void *));
 114 PSEUDO_SET(slattach, if_sl);
 115
 116 /*
 117  * SLRMAX is a hard limit on input packet size.  To simplify the code
 118  * and improve performance, we require that packets fit in an mbuf
 119  * cluster, and if we get a compressed packet, there's enough extra
 120  * room to expand the header into a max length tcp/ip header (128
 121  * bytes).  So, SLRMAX can be at most
 122  *      MCLBYTES - 128
 123  *
 124  * SLMTU is the default transmit MTU. The transmit MTU should be kept
 125  * small enough so that interactive use doesn't suffer, but large
 126  * enough to provide good performance. 552 is a good choice for SLMTU
 127  * because it is high enough to not fragment TCP packets being routed
 128  * through this host. Packet fragmentation is bad with SLIP because
 129  * fragment headers aren't compressed. The previous assumptions about
 130  * the best MTU value don't really hold when using modern modems with
 131  * BTLZ data compression because the modem buffers play a much larger
 132  * role in interactive performance than the MTU. The MTU can be changed
 133  * at any time to suit the specific environment with ifconfig(8), and
 134  * its maximum value is defined as SLTMAX. SLTMAX must not be so large
 135  * that it would overflow the stack if BPF is configured (XXX; if_ppp.c
 136  * handles this better).
 137  *
 138  * SLIP_HIWAT is the amount of data that will be queued 'downstream'
 139  * of us (i.e., in clists waiting to be picked up by the tty output
 140  * interrupt).  If we queue a lot of data downstream, it's immune to
 141  * our t.o.s. queuing.
 142  * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
 143  * telnet/ftp will see a 1 sec wait, independent of the mtu (the
 144  * wait is dependent on the ftp window size but that's typically
 145  * 1k - 4k).  So, we want SLIP_HIWAT just big enough to amortize
 146  * the cost (in idle time on the wire) of the tty driver running
 147  * off the end of its clists & having to call back slstart for a
 148  * new packet.  For a tty interface with any buffering at all, this
 149  * cost will be zero.  Even with a totally brain dead interface (like
 150  * the one on a typical workstation), the cost will be <= 1 character
 151  * time.  So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
 152  * at most 1% while maintaining good interactive response.
 153  */
 154 #define BUFOFFSET       (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
 155 #define SLRMAX          (MCLBYTES - BUFOFFSET)
 156 #define SLBUFSIZE       (SLRMAX + BUFOFFSET)
 157 #ifndef SLMTU
 158 #define SLMTU           552             /* default MTU */
 159 #endif
 160 #define SLTMAX          1500            /* maximum MTU */
 161 #define SLIP_HIWAT      roundup(50,CBSIZE)
 162 #define CLISTRESERVE    1024            /* Can't let clists get too low */
 163
 164 /*
 165  * SLIP ABORT ESCAPE MECHANISM:
 166  *      (inspired by HAYES modem escape arrangement)
 167  *      1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
 168  *      within window time signals a "soft" exit from slip mode by remote end
 169  *      if the IFF_DEBUG flag is on.
 170  */
 171 #define ABT_ESC         '\033'  /* can't be t_intr - distant host must know it*/
 172 #define ABT_IDLE        1       /* in seconds - idle before an escape */
 173 #define ABT_COUNT       3       /* count of escapes for abort */
 174 #define ABT_WINDOW      (ABT_COUNT*2+2) /* in seconds - time to count */
 175
 176 static struct sl_softc sl_softc[NSL];
 177
 178 #define FRAME_END               0xc0            /* Frame End */
 179 #define FRAME_ESCAPE            0xdb            /* Frame Esc */
 180 #define TRANS_FRAME_END         0xdc            /* transposed frame end */
 181 #define TRANS_FRAME_ESCAPE      0xdd            /* transposed frame esc */
 182
 183 static int slinit __P((struct sl_softc *));
 184 static struct mbuf *sl_btom __P((struct sl_softc *, int));
 185 static timeout_t sl_keepalive;
 186 static timeout_t sl_outfill;
 187 static int      slclose __P((struct tty *,int));
 188 static int      slinput __P((int, struct tty *));
 189 static int      slioctl __P((struct ifnet *, u_long, caddr_t));
 190 static int      sltioctl __P((struct tty *, u_long, caddr_t, int, struct proc *));
 191 static int      slopen __P((dev_t, struct tty *));
 192 static int      sloutput __P((struct ifnet *,
 193             struct mbuf *, struct sockaddr *, struct rtentry *));
 194 static int      slstart __P((struct tty *));
 195
 196 static struct linesw slipdisc = {
 197         slopen,         slclose,        l_noread,       l_nowrite,
 198         sltioctl,       slinput,        slstart,        ttymodem,
 199         FRAME_END
 200 };
 201
 202 /*
 203  * Called from boot code to establish sl interfaces.
 204  */
 205 static void
 206 slattach(dummy)
 207         void *dummy;
 208 {
 209         register struct sl_softc *sc;
 210         register int i = 0;
 211
 212         linesw[SLIPDISC] = slipdisc;
 213
 214         for (sc = sl_softc; i < NSL; sc++) {
 215                 sc->sc_if.if_name = "sl";
 216                 sc->sc_if.if_unit = i++;
 217                 sc->sc_if.if_mtu = SLMTU;
 218                 sc->sc_if.if_flags =
 219 #ifdef SLIP_IFF_OPTS
 220                     SLIP_IFF_OPTS;
 221 #else
 222                     IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
 223 #endif
 224                 sc->sc_if.if_type = IFT_SLIP;
 225                 sc->sc_if.if_ioctl = slioctl;
 226                 sc->sc_if.if_output = sloutput;
 227                 sc->sc_if.if_snd.ifq_maxlen = 50;
 228                 sc->sc_fastq.ifq_maxlen = 32;
 229                 sc->sc_if.if_linkmib = sc;
 230                 sc->sc_if.if_linkmiblen = sizeof *sc;
 231                 if_attach(&sc->sc_if);
 232                 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
 233         }
 234 }
 235
 236 static int
 237 slinit(sc)
 238         register struct sl_softc *sc;
 239 {
 240         register caddr_t p;
 241
 242 #ifdef __i386__
 243         int s;
 244
 245         s = splhigh();
 246         tty_imask |= net_imask;
 247         net_imask = tty_imask;
 248         update_intr_masks();
 249         splx(s);
 250         if (bootverbose)
 251                 printf("new imasks: bio %x, tty %x, net %x\n",
 252                     bio_imask, tty_imask, net_imask);
 253 #endif
 254         if (sc->sc_ep == (u_char *) 0) {
 255                 MCLALLOC(p, M_WAIT);
 256                 if (p)
 257                         sc->sc_ep = (u_char *)p + SLBUFSIZE;
 258                 else {
 259                         printf("sl%ld: can't allocate buffer\n",
 260                             (long)(sc - sl_softc));
 261                         return (0);
 262                 }
 263         }
 264         sc->sc_buf = sc->sc_ep - SLRMAX;
 265         sc->sc_mp = sc->sc_buf;
 266         sl_compress_init(&sc->sc_comp, -1);
 267         return (1);
 268 }
 269
 270 /*
 271  * Line specific open routine.
 272  * Attach the given tty to the first available sl unit.
 273  */
 274 /* ARGSUSED */
 275 static int
 276 slopen(dev, tp)
 277         dev_t dev;
 278         register struct tty *tp;
 279 {
 280         struct proc *p = curproc;               /* XXX */
 281         register struct sl_softc *sc;
 282         register int nsl;
 283         int s, error;
 284
 285         error = suser(p);
 286         if (error)
 287                 return (error);
 288
 289         if (tp->t_line == SLIPDISC)
 290                 return (0);
 291
 292         for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++)
 293                 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) {
 294                         if (slinit(sc) == 0)
 295                                 return (ENOBUFS);
 296                         tp->t_sc = (caddr_t)sc;
 297                         sc->sc_ttyp = tp;
 298                         sc->sc_if.if_baudrate = tp->t_ospeed;
 299                         ttyflush(tp, FREAD | FWRITE);
 300
 301                         tp->t_line = SLIPDISC;
 302                         /*
 303                          * We don't use t_canq or t_rawq, so reduce their
 304                          * cblock resources to 0.  Reserve enough cblocks
 305                          * for t_outq to guarantee that we can fit a full
 306                          * packet if the SLIP_HIWAT check allows slstart()
 307                          * to loop.  Use the same value for the cblock
 308                          * limit since the reserved blocks should always
 309                          * be enough.  Reserving cblocks probably makes
 310                          * the CLISTRESERVE check unnecessary and wasteful.
 311                          */
 312                         clist_alloc_cblocks(&tp->t_canq, 0, 0);
 313                         clist_alloc_cblocks(&tp->t_outq,
 314                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
 315                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
 316                         clist_alloc_cblocks(&tp->t_rawq, 0, 0);
 317
 318                         s = splnet();
 319                         if_up(&sc->sc_if);
 320                         splx(s);
 321                         return (0);
 322                 }
 323         return (ENXIO);
 324 }
 325
 326 /*
 327  * Line specific close routine.
 328  * Detach the tty from the sl unit.
 329  */
 330 static int
 331 slclose(tp,flag)
 332         struct tty *tp;
 333         int flag;
 334 {
 335         register struct sl_softc *sc;
 336         int s;
 337
 338         ttyflush(tp, FREAD | FWRITE);
 339         /*
 340          * XXX the placement of the following spl is misleading.  tty
 341          * interrupts must be blocked across line discipline switches
 342          * and throughout closes to avoid races.
 343          */
 344         s = splimp();           /* actually, max(spltty, splnet) */
 345         clist_free_cblocks(&tp->t_outq);
 346         tp->t_line = 0;
 347         sc = (struct sl_softc *)tp->t_sc;
 348         if (sc != NULL) {
 349                 if (sc->sc_outfill) {
 350                         sc->sc_outfill = 0;
 351                         untimeout(sl_outfill, sc, sc->sc_ofhandle);
 352                 }
 353                 if (sc->sc_keepalive) {
 354                         sc->sc_keepalive = 0;
 355                         untimeout(sl_keepalive, sc, sc->sc_kahandle);
 356                 }
 357                 if_down(&sc->sc_if);
 358                 sc->sc_flags &= SC_STATIC;
 359                 sc->sc_ttyp = NULL;
 360                 tp->t_sc = NULL;
 361                 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE));
 362                 sc->sc_ep = 0;
 363                 sc->sc_mp = 0;
 364                 sc->sc_buf = 0;
 365         }
 366         splx(s);
 367         return 0;
 368 }
 369
 370 /*
 371  * Line specific (tty) ioctl routine.
 372  * Provide a way to get the sl unit number.
 373  */
 374 /* ARGSUSED */
 375 static int
 376 sltioctl(tp, cmd, data, flag, p)
 377         struct tty *tp;
 378         u_long cmd;
 379         caddr_t data;
 380         int flag;
 381         struct proc *p;
 382 {
 383         struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc;
 384         int s, nsl;
 385
 386         s = splimp();
 387         switch (cmd) {
 388         case SLIOCGUNIT:
 389                 *(int *)data = sc->sc_if.if_unit;
 390                 break;
 391
 392         case SLIOCSUNIT:
 393                 if (sc->sc_if.if_unit != *(u_int *)data) {
 394                         for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) {
 395                                 if (   nc->sc_if.if_unit == *(u_int *)data
 396                                     && nc->sc_ttyp == NULL
 397                                    ) {
 398                                         tmpnc = malloc(sizeof *tmpnc, M_TEMP,
 399                                                        M_NOWAIT);
 400                                         if (tmpnc == NULL) {
 401                                                 splx(s);
 402                                                 return (ENOMEM);
 403                                         }
 404                                         *tmpnc = *nc;
 405                                         *nc = *sc;
 406                                         nc->sc_if = tmpnc->sc_if;
 407                                         tmpnc->sc_if = sc->sc_if;
 408                                         *sc = *tmpnc;
 409                                         free(tmpnc, M_TEMP);
 410                                         if (sc->sc_if.if_flags & IFF_UP) {
 411                                                 if_down(&sc->sc_if);
 412                                                 if (!(nc->sc_if.if_flags & IFF_UP))
 413                                                         if_up(&nc->sc_if);
 414                                         } else if (nc->sc_if.if_flags & IFF_UP)
 415                                                 if_down(&nc->sc_if);
 416                                         sc->sc_flags &= ~SC_STATIC;
 417                                         sc->sc_flags |= (nc->sc_flags & SC_STATIC);
 418                                         tp->t_sc = sc = nc;
 419                                         clist_alloc_cblocks(&tp->t_outq,
 420                                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
 421                                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
 422                                         sl_compress_init(&sc->sc_comp, -1);
 423                                         goto slfound;
 424                                 }
 425                         }
 426                         splx(s);
 427                         return (ENXIO);
 428                 }
 429         slfound:
 430                 sc->sc_flags |= SC_STATIC;
 431                 break;
 432
 433         case SLIOCSKEEPAL:
 434                 sc->sc_keepalive = *(u_int *)data * hz;
 435                 if (sc->sc_keepalive) {
 436                         sc->sc_flags |= SC_KEEPALIVE;
 437                         sc->sc_kahandle = timeout(sl_keepalive, sc,
 438                                                   sc->sc_keepalive);
 439                 } else {
 440                         if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
 441                                 untimeout(sl_keepalive, sc, sc->sc_kahandle);
 442                                 sc->sc_flags &= ~SC_KEEPALIVE;
 443                         }
 444                 }
 445                 break;
 446
 447         case SLIOCGKEEPAL:
 448                 *(int *)data = sc->sc_keepalive / hz;
 449                 break;
 450
 451         case SLIOCSOUTFILL:
 452                 sc->sc_outfill = *(u_int *)data * hz;
 453                 if (sc->sc_outfill) {
 454                         sc->sc_flags |= SC_OUTWAIT;
 455                         sc->sc_ofhandle = timeout(sl_outfill, sc,
 456                                                   sc->sc_outfill);
 457                 } else {
 458                         if ((sc->sc_flags & SC_OUTWAIT) != 0) {
 459                                 untimeout(sl_outfill, sc, sc->sc_ofhandle);
 460                                 sc->sc_flags &= ~SC_OUTWAIT;
 461                         }
 462                 }
 463                 break;
 464
 465         case SLIOCGOUTFILL:
 466                 *(int *)data = sc->sc_outfill / hz;
 467                 break;
 468
 469         default:
 470                 splx(s);
 471                 return (ENOIOCTL);
 472         }
 473         splx(s);
 474         return (0);
 475 }
 476
 477 /*
 478  * Queue a packet.  Start transmission if not active.
 479  * Compression happens in slstart; if we do it here, IP TOS
 480  * will cause us to not compress "background" packets, because
 481  * ordering gets trashed.  It can be done for all packets in slstart.
 482  */
 483 static int
 484 sloutput(ifp, m, dst, rtp)
 485         struct ifnet *ifp;
 486         register struct mbuf *m;
 487         struct sockaddr *dst;
 488         struct rtentry *rtp;
 489 {
 490         register struct sl_softc *sc = &sl_softc[ifp->if_unit];
 491         register struct ip *ip;
 492         register struct ifqueue *ifq;
 493         int s;
 494
 495         /*
 496          * `Cannot happen' (see slioctl).  Someday we will extend
 497          * the line protocol to support other address families.
 498          */
 499         if (dst->sa_family != AF_INET) {
 500                 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit,
 501                         dst->sa_family);
 502                 m_freem(m);
 503                 sc->sc_if.if_noproto++;
 504                 return (EAFNOSUPPORT);
 505         }
 506
 507         if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
 508                 m_freem(m);
 509                 return (ENETDOWN);
 510         }
 511         if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
 512                 m_freem(m);
 513                 return (EHOSTUNREACH);
 514         }
 515         ifq = &sc->sc_if.if_snd;
 516         ip = mtod(m, struct ip *);
 517         if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
 518                 m_freem(m);
 519                 return (ENETRESET);             /* XXX ? */
 520         }
 521         if (ip->ip_tos & IPTOS_LOWDELAY)
 522                 ifq = &sc->sc_fastq;
 523         s = splimp();
 524         if (IF_QFULL(ifq)) {
 525                 IF_DROP(ifq);
 526                 m_freem(m);
 527                 splx(s);
 528                 sc->sc_if.if_oerrors++;
 529                 return (ENOBUFS);
 530         }
 531         IF_ENQUEUE(ifq, m);
 532         if (sc->sc_ttyp->t_outq.c_cc == 0)
 533                 slstart(sc->sc_ttyp);
 534         splx(s);
 535         return (0);
 536 }
 537
 538 /*
 539  * Start output on interface.  Get another datagram
 540  * to send from the interface queue and map it to
 541  * the interface before starting output.
 542  */
 543 static int
 544 slstart(tp)
 545         register struct tty *tp;
 546 {
 547         register struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
 548         register struct mbuf *m;
 549         register u_char *cp;
 550         register struct ip *ip;
 551         int s;
 552         u_char bpfbuf[SLTMAX + SLIP_HDRLEN];
 553         register int len = 0;
 554
 555         for (;;) {
 556                 /*
 557                  * Call output process whether or not there is more in the
 558                  * output queue.  We are being called in lieu of ttstart
 559                  * and must do what it would.
 560                  */
 561                 (*tp->t_oproc)(tp);
 562
 563                 if (tp->t_outq.c_cc != 0) {
 564                         if (sc != NULL)
 565                                 sc->sc_flags &= ~SC_OUTWAIT;
 566                         if (tp->t_outq.c_cc > SLIP_HIWAT)
 567                                 return 0;
 568                 }
 569
 570                 /*
 571                  * This happens briefly when the line shuts down.
 572                  */
 573                 if (sc == NULL)
 574                         return 0;
 575
 576                 /*
 577                  * Get a packet and send it to the interface.
 578                  */
 579                 s = splimp();
 580                 IF_DEQUEUE(&sc->sc_fastq, m);
 581                 if (m)
 582                         sc->sc_if.if_omcasts++;         /* XXX */
 583                 else
 584                         IF_DEQUEUE(&sc->sc_if.if_snd, m);
 585                 splx(s);
 586                 if (m == NULL)
 587                         return 0;
 588
 589                 /*
 590                  * We do the header compression here rather than in sloutput
 591                  * because the packets will be out of order if we are using TOS
 592                  * queueing, and the connection id compression will get
 593                  * munged when this happens.
 594                  */
 595                 if (sc->sc_if.if_bpf) {
 596                         /*
 597                          * We need to save the TCP/IP header before it's
 598                          * compressed.  To avoid complicated code, we just
 599                          * copy the entire packet into a stack buffer (since
 600                          * this is a serial line, packets should be short
 601                          * and/or the copy should be negligible cost compared
 602                          * to the packet transmission time).
 603                          */
 604                         register struct mbuf *m1 = m;
 605                         register u_char *cp = bpfbuf + SLIP_HDRLEN;
 606
 607                         len = 0;
 608                         do {
 609                                 register int mlen = m1->m_len;
 610
 611                                 bcopy(mtod(m1, caddr_t), cp, mlen);
 612                                 cp += mlen;
 613                                 len += mlen;
 614                         } while ((m1 = m1->m_next) != NULL);
 615                 }
 616                 ip = mtod(m, struct ip *);
 617                 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
 618                         if (sc->sc_if.if_flags & SC_COMPRESS)
 619                                 *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
 620                                     &sc->sc_comp, 1);
 621                 }
 622                 if (sc->sc_if.if_bpf) {
 623                         /*
 624                          * Put the SLIP pseudo-"link header" in place.  The
 625                          * compressed header is now at the beginning of the
 626                          * mbuf.
 627                          */
 628                         bpfbuf[SLX_DIR] = SLIPDIR_OUT;
 629                         bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN);
 630                         bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN);
 631                 }
 632
 633                 /*
 634                  * If system is getting low on clists, just flush our
 635                  * output queue (if the stuff was important, it'll get
 636                  * retransmitted). Note that SLTMAX is used instead of
 637                  * the current if_mtu setting because connections that
 638                  * have already been established still use the original
 639                  * (possibly larger) mss.
 640                  */
 641                 if (cfreecount < CLISTRESERVE + SLTMAX) {
 642                         m_freem(m);
 643                         sc->sc_if.if_collisions++;
 644                         continue;
 645                 }
 646
 647                 sc->sc_flags &= ~SC_OUTWAIT;
 648                 /*
 649                  * The extra FRAME_END will start up a new packet, and thus
 650                  * will flush any accumulated garbage.  We do this whenever
 651                  * the line may have been idle for some time.
 652                  */
 653                 if (tp->t_outq.c_cc == 0) {
 654                         ++sc->sc_if.if_obytes;
 655                         (void) putc(FRAME_END, &tp->t_outq);
 656                 }
 657
 658                 while (m) {
 659                         register u_char *ep;
 660
 661                         cp = mtod(m, u_char *); ep = cp + m->m_len;
 662                         while (cp < ep) {
 663                                 /*
 664                                  * Find out how many bytes in the string we can
 665                                  * handle without doing something special.
 666                                  */
 667                                 register u_char *bp = cp;
 668
 669                                 while (cp < ep) {
 670                                         switch (*cp++) {
 671                                         case FRAME_ESCAPE:
 672                                         case FRAME_END:
 673                                                 --cp;
 674                                                 goto out;
 675                                         }
 676                                 }
 677                                 out:
 678                                 if (cp > bp) {
 679                                         /*
 680                                          * Put n characters at once
 681                                          * into the tty output queue.
 682                                          */
 683                                         if (b_to_q((char *)bp, cp - bp,
 684                                             &tp->t_outq))
 685                                                 break;
 686                                         sc->sc_if.if_obytes += cp - bp;
 687                                 }
 688                                 /*
 689                                  * If there are characters left in the mbuf,
 690                                  * the first one must be special..
 691                                  * Put it out in a different form.
 692                                  */
 693                                 if (cp < ep) {
 694                                         if (putc(FRAME_ESCAPE, &tp->t_outq))
 695                                                 break;
 696                                         if (putc(*cp++ == FRAME_ESCAPE ?
 697                                            TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
 698                                            &tp->t_outq)) {
 699                                                 (void) unputc(&tp->t_outq);
 700                                                 break;
 701                                         }
 702                                         sc->sc_if.if_obytes += 2;
 703                                 }
 704                         }
 705                         m = m_free(m);
 706                 }
 707
 708                 if (putc(FRAME_END, &tp->t_outq)) {
 709                         /*
 710                          * Not enough room.  Remove a char to make room
 711                          * and end the packet normally.
 712                          * If you get many collisions (more than one or two
 713                          * a day) you probably do not have enough clists
 714                          * and you should increase "nclist" in param.c.
 715                          */
 716                         (void) unputc(&tp->t_outq);
 717                         (void) putc(FRAME_END, &tp->t_outq);
 718                         sc->sc_if.if_collisions++;
 719                 } else {
 720                         ++sc->sc_if.if_obytes;
 721                         sc->sc_if.if_opackets++;
 722                 }
 723         }
 724         return 0;
 725 }
 726
 727 /*
 728  * Copy data buffer to mbuf chain; add ifnet pointer.
 729  */
 730 static struct mbuf *
 731 sl_btom(sc, len)
 732         register struct sl_softc *sc;
 733         register int len;
 734 {
 735         register struct mbuf *m;
 736
 737         MGETHDR(m, M_DONTWAIT, MT_DATA);
 738         if (m == NULL)
 739                 return (NULL);
 740
 741         /*
 742          * If we have more than MHLEN bytes, it's cheaper to
 743          * queue the cluster we just filled & allocate a new one
 744          * for the input buffer.  Otherwise, fill the mbuf we
 745          * allocated above.  Note that code in the input routine
 746          * guarantees that packet will fit in a cluster.
 747          */
 748         if (len >= MHLEN) {
 749                 MCLGET(m, M_DONTWAIT);
 750                 if ((m->m_flags & M_EXT) == 0) {
 751                         /*
 752                          * we couldn't get a cluster - if memory's this
 753                          * low, it's time to start dropping packets.
 754                          */
 755                         (void) m_free(m);
 756                         return (NULL);
 757                 }
 758                 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
 759                 m->m_data = (caddr_t)sc->sc_buf;
 760                 m->m_ext.ext_buf = (caddr_t)((intptr_t)sc->sc_buf &~ MCLOFSET);
 761         } else
 762                 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
 763
 764         m->m_len = len;
 765         m->m_pkthdr.len = len;
 766         m->m_pkthdr.rcvif = &sc->sc_if;
 767         return (m);
 768 }
 769
 770 /*
 771  * tty interface receiver interrupt.
 772  */
 773 static int
 774 slinput(c, tp)
 775         register int c;
 776         register struct tty *tp;
 777 {
 778         register struct sl_softc *sc;
 779         register struct mbuf *m;
 780         register int len;
 781         int s;
 782         u_char chdr[CHDR_LEN];
 783
 784         tk_nin++;
 785         sc = (struct sl_softc *)tp->t_sc;
 786         if (sc == NULL)
 787                 return 0;
 788         if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
 789                 sc->sc_flags |= SC_ERROR;
 790                 return 0;
 791         }
 792         c &= TTY_CHARMASK;
 793
 794         ++sc->sc_if.if_ibytes;
 795
 796         if (sc->sc_if.if_flags & IFF_DEBUG) {
 797                 if (c == ABT_ESC) {
 798                         /*
 799                          * If we have a previous abort, see whether
 800                          * this one is within the time limit.
 801                          */
 802                         if (sc->sc_abortcount &&
 803                             time_second >= sc->sc_starttime + ABT_WINDOW)
 804                                 sc->sc_abortcount = 0;
 805                         /*
 806                          * If we see an abort after "idle" time, count it;
 807                          * record when the first abort escape arrived.
 808                          */
 809                         if (time_second >= sc->sc_lasttime + ABT_IDLE) {
 810                                 if (++sc->sc_abortcount == 1)
 811                                         sc->sc_starttime = time_second;
 812                                 if (sc->sc_abortcount >= ABT_COUNT) {
 813                                         slclose(tp,0);
 814                                         return 0;
 815                                 }
 816                         }
 817                 } else
 818                         sc->sc_abortcount = 0;
 819                 sc->sc_lasttime = time_second;
 820         }
 821
 822         switch (c) {
 823
 824         case TRANS_FRAME_ESCAPE:
 825                 if (sc->sc_escape)
 826                         c = FRAME_ESCAPE;
 827                 break;
 828
 829         case TRANS_FRAME_END:
 830                 if (sc->sc_escape)
 831                         c = FRAME_END;
 832                 break;
 833
 834         case FRAME_ESCAPE:
 835                 sc->sc_escape = 1;
 836                 return 0;
 837
 838         case FRAME_END:
 839                 sc->sc_flags &= ~SC_KEEPALIVE;
 840                 if(sc->sc_flags & SC_ERROR) {
 841                         sc->sc_flags &= ~SC_ERROR;
 842                         goto newpack;
 843                 }
 844                 len = sc->sc_mp - sc->sc_buf;
 845                 if (len < 3)
 846                         /* less than min length packet - ignore */
 847                         goto newpack;
 848
 849                 if (sc->sc_if.if_bpf) {
 850                         /*
 851                          * Save the compressed header, so we
 852                          * can tack it on later.  Note that we
 853                          * will end up copying garbage in some
 854                          * cases but this is okay.  We remember
 855                          * where the buffer started so we can
 856                          * compute the new header length.
 857                          */
 858                         bcopy(sc->sc_buf, chdr, CHDR_LEN);
 859                 }
 860
 861                 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
 862                         if (c & 0x80)
 863                                 c = TYPE_COMPRESSED_TCP;
 864                         else if (c == TYPE_UNCOMPRESSED_TCP)
 865                                 *sc->sc_buf &= 0x4f; /* XXX */
 866                         /*
 867                          * We've got something that's not an IP packet.
 868                          * If compression is enabled, try to decompress it.
 869                          * Otherwise, if `auto-enable' compression is on and
 870                          * it's a reasonable packet, decompress it and then
 871                          * enable compression.  Otherwise, drop it.
 872                          */
 873                         if (sc->sc_if.if_flags & SC_COMPRESS) {
 874                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
 875                                                         (u_int)c, &sc->sc_comp);
 876                                 if (len <= 0)
 877                                         goto error;
 878                         } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) &&
 879                             c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
 880                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
 881                                                         (u_int)c, &sc->sc_comp);
 882                                 if (len <= 0)
 883                                         goto error;
 884                                 sc->sc_if.if_flags |= SC_COMPRESS;
 885                         } else
 886                                 goto error;
 887                 }
 888                 if (sc->sc_if.if_bpf) {
 889                         /*
 890                          * Put the SLIP pseudo-"link header" in place.
 891                          * We couldn't do this any earlier since
 892                          * decompression probably moved the buffer
 893                          * pointer.  Then, invoke BPF.
 894                          */
 895                         register u_char *hp = sc->sc_buf - SLIP_HDRLEN;
 896
 897                         hp[SLX_DIR] = SLIPDIR_IN;
 898                         bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
 899                         bpf_tap(&sc->sc_if, hp, len + SLIP_HDRLEN);
 900                 }
 901                 m = sl_btom(sc, len);
 902                 if (m == NULL)
 903                         goto error;
 904
 905                 sc->sc_if.if_ipackets++;
 906
 907                 if ((sc->sc_if.if_flags & IFF_UP) == 0) {
 908                         m_freem(m);
 909                         goto newpack;
 910                 }
 911
 912                 s = splimp();
 913                 if (IF_QFULL(&ipintrq)) {
 914                         IF_DROP(&ipintrq);
 915                         sc->sc_if.if_ierrors++;
 916                         sc->sc_if.if_iqdrops++;
 917                         m_freem(m);
 918                 } else {
 919                         IF_ENQUEUE(&ipintrq, m);
 920                         schednetisr(NETISR_IP);
 921                 }
 922                 splx(s);
 923                 goto newpack;
 924         }
 925         if (sc->sc_mp < sc->sc_ep) {
 926                 *sc->sc_mp++ = c;
 927                 sc->sc_escape = 0;
 928                 return 0;
 929         }
 930
 931         /* can't put lower; would miss an extra frame */
 932         sc->sc_flags |= SC_ERROR;
 933
 934 error:
 935         sc->sc_if.if_ierrors++;
 936 newpack:
 937         sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX;
 938         sc->sc_escape = 0;
 939         return 0;
 940 }
 941
 942 /*
 943  * Process an ioctl request.
 944  */
 945 static int
 946 slioctl(ifp, cmd, data)
 947         register struct ifnet *ifp;
 948         u_long cmd;
 949         caddr_t data;
 950 {
 951         register struct ifaddr *ifa = (struct ifaddr *)data;
 952         register struct ifreq *ifr = (struct ifreq *)data;
 953         register int s, error = 0;
 954
 955         s = splimp();
 956
 957         switch (cmd) {
 958
 959         case SIOCSIFFLAGS:
 960                 /*
 961                  * if.c will set the interface up even if we
 962                  * don't want it to.
 963                  */
 964                 if (sl_softc[ifp->if_unit].sc_ttyp == NULL) {
 965                         ifp->if_flags &= ~IFF_UP;
 966                 }
 967                 break;
 968         case SIOCSIFADDR:
 969                 /*
 970                  * This is "historical" - set the interface up when
 971                  * setting the address.
 972                  */
 973                 if (ifa->ifa_addr->sa_family == AF_INET) {
 974                         if (sl_softc[ifp->if_unit].sc_ttyp != NULL)
 975                                 ifp->if_flags |= IFF_UP;
 976                 } else {
 977                         error = EAFNOSUPPORT;
 978                 }
 979                 break;
 980
 981         case SIOCSIFDSTADDR:
 982                 if (ifa->ifa_addr->sa_family != AF_INET)
 983                         error = EAFNOSUPPORT;
 984                 break;
 985
 986         case SIOCADDMULTI:
 987         case SIOCDELMULTI:
 988                 break;
 989
 990         case SIOCSIFMTU:
 991                 /*
 992                  * Set the interface MTU.
 993                  */
 994                 if (ifr->ifr_mtu > SLTMAX)
 995                         error = EINVAL;
 996                 else {
 997                         struct tty *tp;
 998
 999                         ifp->if_mtu = ifr->ifr_mtu;
1000                         tp = sl_softc[ifp->if_unit].sc_ttyp;
1001                         if (tp != NULL)
1002                                 clist_alloc_cblocks(&tp->t_outq,
1003                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1,
1004                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1);
1005                 }
1006                 break;
1007
1008         default:
1009                 error = EINVAL;
1010         }
1011         splx(s);
1012         return (error);
1013 }
1014
1015 static void
1016 sl_keepalive(chan)
1017         void *chan;
1018 {
1019         struct sl_softc *sc = chan;
1020
1021         if (sc->sc_keepalive) {
1022                 if (sc->sc_flags & SC_KEEPALIVE)
1023                         pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1);
1024                 else
1025                         sc->sc_flags |= SC_KEEPALIVE;
1026                 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
1027         } else {
1028                 sc->sc_flags &= ~SC_KEEPALIVE;
1029         }
1030 }
1031
1032 static void
1033 sl_outfill(chan)
1034         void *chan;
1035 {
1036         struct sl_softc *sc = chan;
1037         register struct tty *tp = sc->sc_ttyp;
1038         int s;
1039
1040         if (sc->sc_outfill && tp != NULL) {
1041                 if (sc->sc_flags & SC_OUTWAIT) {
1042                         s = splimp ();
1043                         ++sc->sc_if.if_obytes;
1044                         (void) putc(FRAME_END, &tp->t_outq);
1045                         (*tp->t_oproc)(tp);
1046                         splx (s);
1047                 } else
1048                         sc->sc_flags |= SC_OUTWAIT;
1049                 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
1050         } else {
1051                 sc->sc_flags &= ~SC_OUTWAIT;
1052         }
1053 }