sys/net/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  * $Id: if_sl.c,v 1.69 1998/06/07 17:12:05 dfr Exp $
  35  */
  36
  37 /*
  38  * Serial Line interface
  39  *
  40  * Rick Adams
  41  * Center for Seismic Studies
  42  * 1300 N 17th Street, Suite 1450
  43  * Arlington, Virginia 22209
  44  * (703)276-7900
  45  * rick@seismo.ARPA
  46  * seismo!rick
  47  *
  48  * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris).
  49  * N.B.: this belongs in netinet, not net, the way it stands now.
  50  * Should have a link-layer type designation, but wouldn't be
  51  * backwards-compatible.
  52  *
  53  * Converted to 4.3BSD Beta by Chris Torek.
  54  * Other changes made at Berkeley, based in part on code by Kirk Smith.
  55  * W. Jolitz added slip abort.
  56  *
  57  * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov).
  58  * Added priority queuing for "interactive" traffic; hooks for TCP
  59  * header compression; ICMP filtering (at 2400 baud, some cretin
  60  * pinging you can use up all your bandwidth).  Made low clist behavior
  61  * more robust and slightly less likely to hang serial line.
  62  * Sped up a bunch of things.
  63  *
  64  * Note that splimp() is used throughout to block both (tty) input
  65  * interrupts and network activity; thus, splimp must be >= spltty.
  66  */
  67
  68 #include "sl.h"
  69 #if NSL > 0
  70
  71 #include "bpfilter.h"
  72 #include "opt_inet.h"
  73
  74 #include <sys/param.h>
  75 #include <sys/systm.h>
  76 #include <sys/proc.h>
  77 #include <sys/malloc.h>
  78 #include <sys/mbuf.h>
  79 #include <sys/dkstat.h>
  80 #include <sys/socket.h>
  81 #include <sys/sockio.h>
  82 #include <sys/fcntl.h>
  83 #include <sys/signalvar.h>
  84 #include <sys/tty.h>
  85 #include <sys/clist.h>
  86 #include <sys/kernel.h>
  87 #include <sys/conf.h>
  88
  89 #include <net/if.h>
  90 #include <net/if_types.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 <net/if_slvar.h>
 104 #include <net/slip.h>
 105
 106 #if NBPFILTER > 0
 107 #include <net/bpf.h>
 108 #endif
 109
 110 static void slattach __P((void *));
 111 PSEUDO_SET(slattach, if_sl);
 112
 113 /*
 114  * SLRMAX is a hard limit on input packet size.  To simplify the code
 115  * and improve performance, we require that packets fit in an mbuf
 116  * cluster, and if we get a compressed packet, there's enough extra
 117  * room to expand the header into a max length tcp/ip header (128
 118  * bytes).  So, SLRMAX can be at most
 119  *      MCLBYTES - 128
 120  *
 121  * SLMTU is the default transmit MTU. The transmit MTU should be kept
 122  * small enough so that interactive use doesn't suffer, but large
 123  * enough to provide good performance. 552 is a good choice for SLMTU
 124  * because it is high enough to not fragment TCP packets being routed
 125  * through this host. Packet fragmentation is bad with SLIP because
 126  * fragment headers aren't compressed. The previous assumptions about
 127  * the best MTU value don't really hold when using modern modems with
 128  * BTLZ data compression because the modem buffers play a much larger
 129  * role in interactive performance than the MTU. The MTU can be changed
 130  * at any time to suit the specific environment with ifconfig(8), and
 131  * its maximum value is defined as SLTMAX. SLTMAX must not be so large
 132  * that it would overflow the stack if BPF is configured (XXX; if_ppp.c
 133  * handles this better).
 134  *
 135  * SLIP_HIWAT is the amount of data that will be queued 'downstream'
 136  * of us (i.e., in clists waiting to be picked up by the tty output
 137  * interrupt).  If we queue a lot of data downstream, it's immune to
 138  * our t.o.s. queuing.
 139  * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
 140  * telnet/ftp will see a 1 sec wait, independent of the mtu (the
 141  * wait is dependent on the ftp window size but that's typically
 142  * 1k - 4k).  So, we want SLIP_HIWAT just big enough to amortize
 143  * the cost (in idle time on the wire) of the tty driver running
 144  * off the end of its clists & having to call back slstart for a
 145  * new packet.  For a tty interface with any buffering at all, this
 146  * cost will be zero.  Even with a totally brain dead interface (like
 147  * the one on a typical workstation), the cost will be <= 1 character
 148  * time.  So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
 149  * at most 1% while maintaining good interactive response.
 150  */
 151 #if NBPFILTER > 0
 152 #define BUFOFFSET       (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
 153 #else
 154 #define BUFOFFSET       (128+sizeof(struct ifnet **))
 155 #endif
 156 #define SLRMAX          (MCLBYTES - BUFOFFSET)
 157 #define SLBUFSIZE       (SLRMAX + BUFOFFSET)
 158 #ifndef SLMTU
 159 #define SLMTU           552             /* default MTU */
 160 #endif
 161 #define SLTMAX          1500            /* maximum MTU */
 162 #define SLIP_HIWAT      roundup(50,CBSIZE)
 163 #define CLISTRESERVE    1024            /* Can't let clists get too low */
 164
 165 /*
 166  * SLIP ABORT ESCAPE MECHANISM:
 167  *      (inspired by HAYES modem escape arrangement)
 168  *      1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
 169  *      within window time signals a "soft" exit from slip mode by remote end
 170  *      if the IFF_DEBUG flag is on.
 171  */
 172 #define ABT_ESC         '\033'  /* can't be t_intr - distant host must know it*/
 173 #define ABT_IDLE        1       /* in seconds - idle before an escape */
 174 #define ABT_COUNT       3       /* count of escapes for abort */
 175 #define ABT_WINDOW      (ABT_COUNT*2+2) /* in seconds - time to count */
 176
 177 static struct sl_softc sl_softc[NSL];
 178
 179 #define FRAME_END               0xc0            /* Frame End */
 180 #define FRAME_ESCAPE            0xdb            /* Frame Esc */
 181 #define TRANS_FRAME_END         0xdc            /* transposed frame end */
 182 #define TRANS_FRAME_ESCAPE      0xdd            /* transposed frame esc */
 183
 184 static int slinit __P((struct sl_softc *));
 185 static struct mbuf *sl_btom __P((struct sl_softc *, int));
 186 static timeout_t sl_keepalive;
 187 static timeout_t sl_outfill;
 188 static int      slclose __P((struct tty *,int));
 189 static int      slinput __P((int, struct tty *));
 190 static int      slioctl __P((struct ifnet *, u_long, caddr_t));
 191 static int      sltioctl __P((struct tty *, u_long, caddr_t, int, struct proc *));
 192 static int      slopen __P((dev_t, struct tty *));
 193 static int      sloutput __P((struct ifnet *,
 194             struct mbuf *, struct sockaddr *, struct rtentry *));
 195 static int      slstart __P((struct tty *));
 196
 197 static struct linesw slipdisc = {
 198         slopen,         slclose,        l_noread,       l_nowrite,
 199         sltioctl,       slinput,        slstart,        ttymodem,
 200         FRAME_END
 201 };
 202
 203 /*
 204  * Called from boot code to establish sl interfaces.
 205  */
 206 static void
 207 slattach(dummy)
 208         void *dummy;
 209 {
 210         register struct sl_softc *sc;
 211         register int i = 0;
 212
 213         linesw[SLIPDISC] = slipdisc;
 214
 215         for (sc = sl_softc; i < NSL; sc++) {
 216                 sc->sc_if.if_name = "sl";
 217                 sc->sc_if.if_unit = i++;
 218                 sc->sc_if.if_mtu = SLMTU;
 219                 sc->sc_if.if_flags =
 220                     IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
 221                 sc->sc_if.if_type = IFT_SLIP;
 222                 sc->sc_if.if_ioctl = slioctl;
 223                 sc->sc_if.if_output = sloutput;
 224                 sc->sc_if.if_snd.ifq_maxlen = 50;
 225                 sc->sc_fastq.ifq_maxlen = 32;
 226                 sc->sc_if.if_linkmib = sc;
 227                 sc->sc_if.if_linkmiblen = sizeof *sc;
 228                 if_attach(&sc->sc_if);
 229 #if NBPFILTER > 0
 230                 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
 231 #endif
 232         }
 233 }
 234
 235 static int
 236 slinit(sc)
 237         register struct sl_softc *sc;
 238 {
 239         register caddr_t p;
 240
 241         if (sc->sc_ep == (u_char *) 0) {
 242                 MCLALLOC(p, M_WAIT);
 243                 if (p)
 244                         sc->sc_ep = (u_char *)p + SLBUFSIZE;
 245                 else {
 246                         printf("sl%d: can't allocate buffer\n", sc - sl_softc);
 247                         return (0);
 248                 }
 249         }
 250         sc->sc_buf = sc->sc_ep - SLRMAX;
 251         sc->sc_mp = sc->sc_buf;
 252         sl_compress_init(&sc->sc_comp, -1);
 253         return (1);
 254 }
 255
 256 /*
 257  * Line specific open routine.
 258  * Attach the given tty to the first available sl unit.
 259  */
 260 /* ARGSUSED */
 261 static int
 262 slopen(dev, tp)
 263         dev_t dev;
 264         register struct tty *tp;
 265 {
 266         struct proc *p = curproc;               /* XXX */
 267         register struct sl_softc *sc;
 268         register int nsl;
 269         int s, error;
 270
 271         error = suser(p->p_ucred, &p->p_acflag);
 272         if (error)
 273                 return (error);
 274
 275         if (tp->t_line == SLIPDISC)
 276                 return (0);
 277
 278         for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++)
 279                 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) {
 280                         if (slinit(sc) == 0)
 281                                 return (ENOBUFS);
 282                         tp->t_sc = (caddr_t)sc;
 283                         sc->sc_ttyp = tp;
 284                         sc->sc_if.if_baudrate = tp->t_ospeed;
 285                         ttyflush(tp, FREAD | FWRITE);
 286
 287                         tp->t_line = SLIPDISC;
 288                         /*
 289                          * We don't use t_canq or t_rawq, so reduce their
 290                          * cblock resources to 0.  Reserve enough cblocks
 291                          * for t_outq to guarantee that we can fit a full
 292                          * packet if the SLIP_HIWAT check allows slstart()
 293                          * to loop.  Use the same value for the cblock
 294                          * limit since the reserved blocks should always
 295                          * be enough.  Reserving cblocks probably makes
 296                          * the CLISTRESERVE check unnecessary and wasteful.
 297                          */
 298                         clist_alloc_cblocks(&tp->t_canq, 0, 0);
 299                         clist_alloc_cblocks(&tp->t_outq,
 300                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
 301                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
 302                         clist_alloc_cblocks(&tp->t_rawq, 0, 0);
 303
 304                         s = splnet();
 305                         if_up(&sc->sc_if);
 306                         splx(s);
 307                         return (0);
 308                 }
 309         return (ENXIO);
 310 }
 311
 312 /*
 313  * Line specific close routine.
 314  * Detach the tty from the sl unit.
 315  */
 316 static int
 317 slclose(tp,flag)
 318         struct tty *tp;
 319         int flag;
 320 {
 321         register struct sl_softc *sc;
 322         int s;
 323
 324         ttyflush(tp, FREAD | FWRITE);
 325         /*
 326          * XXX the placement of the following spl is misleading.  tty
 327          * interrupts must be blocked across line discipline switches
 328          * and throughout closes to avoid races.
 329          */
 330         s = splimp();           /* actually, max(spltty, splnet) */
 331         clist_free_cblocks(&tp->t_outq);
 332         tp->t_line = 0;
 333         sc = (struct sl_softc *)tp->t_sc;
 334         if (sc != NULL) {
 335                 if (sc->sc_outfill) {
 336                         sc->sc_outfill = 0;
 337                         untimeout(sl_outfill, sc, sc->sc_ofhandle);
 338                 }
 339                 if (sc->sc_keepalive) {
 340                         sc->sc_keepalive = 0;
 341                         untimeout(sl_keepalive, sc, sc->sc_kahandle);
 342                 }
 343                 if_down(&sc->sc_if);
 344                 sc->sc_flags &= SC_STATIC;
 345                 sc->sc_ttyp = NULL;
 346                 tp->t_sc = NULL;
 347                 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE));
 348                 sc->sc_ep = 0;
 349                 sc->sc_mp = 0;
 350                 sc->sc_buf = 0;
 351         }
 352         splx(s);
 353         return 0;
 354 }
 355
 356 /*
 357  * Line specific (tty) ioctl routine.
 358  * Provide a way to get the sl unit number.
 359  */
 360 /* ARGSUSED */
 361 static int
 362 sltioctl(tp, cmd, data, flag, p)
 363         struct tty *tp;
 364         u_long cmd;
 365         caddr_t data;
 366         int flag;
 367         struct proc *p;
 368 {
 369         struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc;
 370         int s, nsl;
 371
 372         s = splimp();
 373         switch (cmd) {
 374         case SLIOCGUNIT:
 375                 *(int *)data = sc->sc_if.if_unit;
 376                 break;
 377
 378         case SLIOCSUNIT:
 379                 if (sc->sc_if.if_unit != *(u_int *)data) {
 380                         for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) {
 381                                 if (   nc->sc_if.if_unit == *(u_int *)data
 382                                     && nc->sc_ttyp == NULL
 383                                    ) {
 384                                         tmpnc = malloc(sizeof *tmpnc, M_TEMP,
 385                                                        M_NOWAIT);
 386                                         if (tmpnc == NULL) {
 387                                                 splx(s);
 388                                                 return (ENOMEM);
 389                                         }
 390                                         *tmpnc = *nc;
 391                                         *nc = *sc;
 392                                         nc->sc_if = tmpnc->sc_if;
 393                                         tmpnc->sc_if = sc->sc_if;
 394                                         *sc = *tmpnc;
 395                                         free(tmpnc, M_TEMP);
 396                                         if (sc->sc_if.if_flags & IFF_UP) {
 397                                                 if_down(&sc->sc_if);
 398                                                 if (!(nc->sc_if.if_flags & IFF_UP))
 399                                                         if_up(&nc->sc_if);
 400                                         } else if (nc->sc_if.if_flags & IFF_UP)
 401                                                 if_down(&nc->sc_if);
 402                                         sc->sc_flags &= ~SC_STATIC;
 403                                         sc->sc_flags |= (nc->sc_flags & SC_STATIC);
 404                                         tp->t_sc = sc = nc;
 405                                         goto slfound;
 406                                 }
 407                         }
 408                         splx(s);
 409                         return (ENXIO);
 410                 }
 411         slfound:
 412                 sc->sc_flags |= SC_STATIC;
 413                 break;
 414
 415         case SLIOCSKEEPAL:
 416                 sc->sc_keepalive = *(u_int *)data * hz;
 417                 if (sc->sc_keepalive) {
 418                         sc->sc_flags |= SC_KEEPALIVE;
 419                         sc->sc_kahandle = timeout(sl_keepalive, sc,
 420                                                   sc->sc_keepalive);
 421                 } else {
 422                         if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
 423                                 untimeout(sl_keepalive, sc, sc->sc_kahandle);
 424                                 sc->sc_flags &= ~SC_KEEPALIVE;
 425                         }
 426                 }
 427                 break;
 428
 429         case SLIOCGKEEPAL:
 430                 *(int *)data = sc->sc_keepalive / hz;
 431                 break;
 432
 433         case SLIOCSOUTFILL:
 434                 sc->sc_outfill = *(u_int *)data * hz;
 435                 if (sc->sc_outfill) {
 436                         sc->sc_flags |= SC_OUTWAIT;
 437                         sc->sc_ofhandle = timeout(sl_outfill, sc,
 438                                                   sc->sc_outfill);
 439                 } else {
 440                         if ((sc->sc_flags & SC_OUTWAIT) != 0) {
 441                                 untimeout(sl_outfill, sc, sc->sc_ofhandle);
 442                                 sc->sc_flags &= ~SC_OUTWAIT;
 443                         }
 444                 }
 445                 break;
 446
 447         case SLIOCGOUTFILL:
 448                 *(int *)data = sc->sc_outfill / hz;
 449                 break;
 450
 451         default:
 452                 splx(s);
 453                 return (ENOIOCTL);
 454         }
 455         splx(s);
 456         return (0);
 457 }
 458
 459 /*
 460  * Queue a packet.  Start transmission if not active.
 461  * Compression happens in slstart; if we do it here, IP TOS
 462  * will cause us to not compress "background" packets, because
 463  * ordering gets trashed.  It can be done for all packets in slstart.
 464  */
 465 static int
 466 sloutput(ifp, m, dst, rtp)
 467         struct ifnet *ifp;
 468         register struct mbuf *m;
 469         struct sockaddr *dst;
 470         struct rtentry *rtp;
 471 {
 472         register struct sl_softc *sc = &sl_softc[ifp->if_unit];
 473         register struct ip *ip;
 474         register struct ifqueue *ifq;
 475         int s;
 476
 477         /*
 478          * `Cannot happen' (see slioctl).  Someday we will extend
 479          * the line protocol to support other address families.
 480          */
 481         if (dst->sa_family != AF_INET) {
 482                 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit,
 483                         dst->sa_family);
 484                 m_freem(m);
 485                 sc->sc_if.if_noproto++;
 486                 return (EAFNOSUPPORT);
 487         }
 488
 489         if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
 490                 m_freem(m);
 491                 return (ENETDOWN);
 492         }
 493         if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
 494                 m_freem(m);
 495                 return (EHOSTUNREACH);
 496         }
 497         ifq = &sc->sc_if.if_snd;
 498         ip = mtod(m, struct ip *);
 499         if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
 500                 m_freem(m);
 501                 return (ENETRESET);             /* XXX ? */
 502         }
 503         if (ip->ip_tos & IPTOS_LOWDELAY)
 504                 ifq = &sc->sc_fastq;
 505         s = splimp();
 506         if (IF_QFULL(ifq)) {
 507                 IF_DROP(ifq);
 508                 m_freem(m);
 509                 splx(s);
 510                 sc->sc_if.if_oerrors++;
 511                 return (ENOBUFS);
 512         }
 513         IF_ENQUEUE(ifq, m);
 514         if (sc->sc_ttyp->t_outq.c_cc == 0)
 515                 slstart(sc->sc_ttyp);
 516         splx(s);
 517         return (0);
 518 }
 519
 520 /*
 521  * Start output on interface.  Get another datagram
 522  * to send from the interface queue and map it to
 523  * the interface before starting output.
 524  */
 525 static int
 526 slstart(tp)
 527         register struct tty *tp;
 528 {
 529         register struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
 530         register struct mbuf *m;
 531         register u_char *cp;
 532         register struct ip *ip;
 533         int s;
 534         struct mbuf *m2;
 535 #if NBPFILTER > 0
 536         u_char bpfbuf[SLTMAX + SLIP_HDRLEN];
 537         register int len = 0;
 538 #endif
 539
 540         for (;;) {
 541                 /*
 542                  * Call output process whether or not there is more in the
 543                  * output queue.  We are being called in lieu of ttstart
 544                  * and must do what it would.
 545                  */
 546                 (*tp->t_oproc)(tp);
 547
 548                 if (tp->t_outq.c_cc != 0) {
 549                         if (sc != NULL)
 550                                 sc->sc_flags &= ~SC_OUTWAIT;
 551                         if (tp->t_outq.c_cc > SLIP_HIWAT)
 552                                 return 0;
 553                 }
 554
 555                 /*
 556                  * This happens briefly when the line shuts down.
 557                  */
 558                 if (sc == NULL)
 559                         return 0;
 560
 561                 /*
 562                  * Get a packet and send it to the interface.
 563                  */
 564                 s = splimp();
 565                 IF_DEQUEUE(&sc->sc_fastq, m);
 566                 if (m)
 567                         sc->sc_if.if_omcasts++;         /* XXX */
 568                 else
 569                         IF_DEQUEUE(&sc->sc_if.if_snd, m);
 570                 splx(s);
 571                 if (m == NULL)
 572                         return 0;
 573
 574                 /*
 575                  * We do the header compression here rather than in sloutput
 576                  * because the packets will be out of order if we are using TOS
 577                  * queueing, and the connection id compression will get
 578                  * munged when this happens.
 579                  */
 580 #if NBPFILTER > 0
 581                 if (sc->sc_if.if_bpf) {
 582                         /*
 583                          * We need to save the TCP/IP header before it's
 584                          * compressed.  To avoid complicated code, we just
 585                          * copy the entire packet into a stack buffer (since
 586                          * this is a serial line, packets should be short
 587                          * and/or the copy should be negligible cost compared
 588                          * to the packet transmission time).
 589                          */
 590                         register struct mbuf *m1 = m;
 591                         register u_char *cp = bpfbuf + SLIP_HDRLEN;
 592
 593                         len = 0;
 594                         do {
 595                                 register int mlen = m1->m_len;
 596
 597                                 bcopy(mtod(m1, caddr_t), cp, mlen);
 598                                 cp += mlen;
 599                                 len += mlen;
 600                         } while (m1 = m1->m_next);
 601                 }
 602 #endif
 603                 ip = mtod(m, struct ip *);
 604                 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
 605                         if (sc->sc_if.if_flags & SC_COMPRESS)
 606                                 *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
 607                                     &sc->sc_comp, 1);
 608                 }
 609 #if NBPFILTER > 0
 610                 if (sc->sc_if.if_bpf) {
 611                         /*
 612                          * Put the SLIP pseudo-"link header" in place.  The
 613                          * compressed header is now at the beginning of the
 614                          * mbuf.
 615                          */
 616                         bpfbuf[SLX_DIR] = SLIPDIR_OUT;
 617                         bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN);
 618                         bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN);
 619                 }
 620 #endif
 621
 622                 /*
 623                  * If system is getting low on clists, just flush our
 624                  * output queue (if the stuff was important, it'll get
 625                  * retransmitted). Note that SLTMAX is used instead of
 626                  * the current if_mtu setting because connections that
 627                  * have already been established still use the original
 628                  * (possibly larger) mss.
 629                  */
 630                 if (cfreecount < CLISTRESERVE + SLTMAX) {
 631                         m_freem(m);
 632                         sc->sc_if.if_collisions++;
 633                         continue;
 634                 }
 635
 636                 sc->sc_flags &= ~SC_OUTWAIT;
 637                 /*
 638                  * The extra FRAME_END will start up a new packet, and thus
 639                  * will flush any accumulated garbage.  We do this whenever
 640                  * the line may have been idle for some time.
 641                  */
 642                 if (tp->t_outq.c_cc == 0) {
 643                         ++sc->sc_if.if_obytes;
 644                         (void) putc(FRAME_END, &tp->t_outq);
 645                 }
 646
 647                 while (m) {
 648                         register u_char *ep;
 649
 650                         cp = mtod(m, u_char *); ep = cp + m->m_len;
 651                         while (cp < ep) {
 652                                 /*
 653                                  * Find out how many bytes in the string we can
 654                                  * handle without doing something special.
 655                                  */
 656                                 register u_char *bp = cp;
 657
 658                                 while (cp < ep) {
 659                                         switch (*cp++) {
 660                                         case FRAME_ESCAPE:
 661                                         case FRAME_END:
 662                                                 --cp;
 663                                                 goto out;
 664                                         }
 665                                 }
 666                                 out:
 667                                 if (cp > bp) {
 668                                         /*
 669                                          * Put n characters at once
 670                                          * into the tty output queue.
 671                                          */
 672                                         if (b_to_q((char *)bp, cp - bp,
 673                                             &tp->t_outq))
 674                                                 break;
 675                                         sc->sc_if.if_obytes += cp - bp;
 676                                 }
 677                                 /*
 678                                  * If there are characters left in the mbuf,
 679                                  * the first one must be special..
 680                                  * Put it out in a different form.
 681                                  */
 682                                 if (cp < ep) {
 683                                         if (putc(FRAME_ESCAPE, &tp->t_outq))
 684                                                 break;
 685                                         if (putc(*cp++ == FRAME_ESCAPE ?
 686                                            TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
 687                                            &tp->t_outq)) {
 688                                                 (void) unputc(&tp->t_outq);
 689                                                 break;
 690                                         }
 691                                         sc->sc_if.if_obytes += 2;
 692                                 }
 693                         }
 694                         MFREE(m, m2);
 695                         m = m2;
 696                 }
 697
 698                 if (putc(FRAME_END, &tp->t_outq)) {
 699                         /*
 700                          * Not enough room.  Remove a char to make room
 701                          * and end the packet normally.
 702                          * If you get many collisions (more than one or two
 703                          * a day) you probably do not have enough clists
 704                          * and you should increase "nclist" in param.c.
 705                          */
 706                         (void) unputc(&tp->t_outq);
 707                         (void) putc(FRAME_END, &tp->t_outq);
 708                         sc->sc_if.if_collisions++;
 709                 } else {
 710                         ++sc->sc_if.if_obytes;
 711                         sc->sc_if.if_opackets++;
 712                 }
 713         }
 714         return 0;
 715 }
 716
 717 /*
 718  * Copy data buffer to mbuf chain; add ifnet pointer.
 719  */
 720 static struct mbuf *
 721 sl_btom(sc, len)
 722         register struct sl_softc *sc;
 723         register int len;
 724 {
 725         register struct mbuf *m;
 726
 727         MGETHDR(m, M_DONTWAIT, MT_DATA);
 728         if (m == NULL)
 729                 return (NULL);
 730
 731         /*
 732          * If we have more than MHLEN bytes, it's cheaper to
 733          * queue the cluster we just filled & allocate a new one
 734          * for the input buffer.  Otherwise, fill the mbuf we
 735          * allocated above.  Note that code in the input routine
 736          * guarantees that packet will fit in a cluster.
 737          */
 738         if (len >= MHLEN) {
 739                 MCLGET(m, M_DONTWAIT);
 740                 if ((m->m_flags & M_EXT) == 0) {
 741                         /*
 742                          * we couldn't get a cluster - if memory's this
 743                          * low, it's time to start dropping packets.
 744                          */
 745                         (void) m_free(m);
 746                         return (NULL);
 747                 }
 748                 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
 749                 m->m_data = (caddr_t)sc->sc_buf;
 750                 m->m_ext.ext_buf = (caddr_t)((intptr_t)sc->sc_buf &~ MCLOFSET);
 751         } else
 752                 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
 753
 754         m->m_len = len;
 755         m->m_pkthdr.len = len;
 756         m->m_pkthdr.rcvif = &sc->sc_if;
 757         return (m);
 758 }
 759
 760 /*
 761  * tty interface receiver interrupt.
 762  */
 763 static int
 764 slinput(c, tp)
 765         register int c;
 766         register struct tty *tp;
 767 {
 768         register struct sl_softc *sc;
 769         register struct mbuf *m;
 770         register int len;
 771         int s;
 772 #if NBPFILTER > 0
 773         u_char chdr[CHDR_LEN];
 774 #endif
 775
 776         tk_nin++;
 777         sc = (struct sl_softc *)tp->t_sc;
 778         if (sc == NULL)
 779                 return 0;
 780         if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
 781                 sc->sc_flags |= SC_ERROR;
 782                 return 0;
 783         }
 784         c &= TTY_CHARMASK;
 785
 786         ++sc->sc_if.if_ibytes;
 787
 788         if (sc->sc_if.if_flags & IFF_DEBUG) {
 789                 if (c == ABT_ESC) {
 790                         /*
 791                          * If we have a previous abort, see whether
 792                          * this one is within the time limit.
 793                          */
 794                         if (sc->sc_abortcount &&
 795                             time_second >= sc->sc_starttime + ABT_WINDOW)
 796                                 sc->sc_abortcount = 0;
 797                         /*
 798                          * If we see an abort after "idle" time, count it;
 799                          * record when the first abort escape arrived.
 800                          */
 801                         if (time_second >= sc->sc_lasttime + ABT_IDLE) {
 802                                 if (++sc->sc_abortcount == 1)
 803                                         sc->sc_starttime = time_second;
 804                                 if (sc->sc_abortcount >= ABT_COUNT) {
 805                                         slclose(tp,0);
 806                                         return 0;
 807                                 }
 808                         }
 809                 } else
 810                         sc->sc_abortcount = 0;
 811                 sc->sc_lasttime = time_second;
 812         }
 813
 814         switch (c) {
 815
 816         case TRANS_FRAME_ESCAPE:
 817                 if (sc->sc_escape)
 818                         c = FRAME_ESCAPE;
 819                 break;
 820
 821         case TRANS_FRAME_END:
 822                 if (sc->sc_escape)
 823                         c = FRAME_END;
 824                 break;
 825
 826         case FRAME_ESCAPE:
 827                 sc->sc_escape = 1;
 828                 return 0;
 829
 830         case FRAME_END:
 831                 sc->sc_flags &= ~SC_KEEPALIVE;
 832                 if(sc->sc_flags & SC_ERROR) {
 833                         sc->sc_flags &= ~SC_ERROR;
 834                         goto newpack;
 835                 }
 836                 len = sc->sc_mp - sc->sc_buf;
 837                 if (len < 3)
 838                         /* less than min length packet - ignore */
 839                         goto newpack;
 840
 841 #if NBPFILTER > 0
 842                 if (sc->sc_if.if_bpf) {
 843                         /*
 844                          * Save the compressed header, so we
 845                          * can tack it on later.  Note that we
 846                          * will end up copying garbage in some
 847                          * cases but this is okay.  We remember
 848                          * where the buffer started so we can
 849                          * compute the new header length.
 850                          */
 851                         bcopy(sc->sc_buf, chdr, CHDR_LEN);
 852                 }
 853 #endif
 854
 855                 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
 856                         if (c & 0x80)
 857                                 c = TYPE_COMPRESSED_TCP;
 858                         else if (c == TYPE_UNCOMPRESSED_TCP)
 859                                 *sc->sc_buf &= 0x4f; /* XXX */
 860                         /*
 861                          * We've got something that's not an IP packet.
 862                          * If compression is enabled, try to decompress it.
 863                          * Otherwise, if `auto-enable' compression is on and
 864                          * it's a reasonable packet, decompress it and then
 865                          * enable compression.  Otherwise, drop it.
 866                          */
 867                         if (sc->sc_if.if_flags & SC_COMPRESS) {
 868                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
 869                                                         (u_int)c, &sc->sc_comp);
 870                                 if (len <= 0)
 871                                         goto error;
 872                         } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) &&
 873                             c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
 874                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
 875                                                         (u_int)c, &sc->sc_comp);
 876                                 if (len <= 0)
 877                                         goto error;
 878                                 sc->sc_if.if_flags |= SC_COMPRESS;
 879                         } else
 880                                 goto error;
 881                 }
 882 #if NBPFILTER > 0
 883                 if (sc->sc_if.if_bpf) {
 884                         /*
 885                          * Put the SLIP pseudo-"link header" in place.
 886                          * We couldn't do this any earlier since
 887                          * decompression probably moved the buffer
 888                          * pointer.  Then, invoke BPF.
 889                          */
 890                         register u_char *hp = sc->sc_buf - SLIP_HDRLEN;
 891
 892                         hp[SLX_DIR] = SLIPDIR_IN;
 893                         bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
 894                         bpf_tap(&sc->sc_if, hp, len + SLIP_HDRLEN);
 895                 }
 896 #endif
 897                 m = sl_btom(sc, len);
 898                 if (m == NULL)
 899                         goto error;
 900
 901                 sc->sc_if.if_ipackets++;
 902
 903                 if ((sc->sc_if.if_flags & IFF_UP) == 0) {
 904                         m_freem(m);
 905                         goto newpack;
 906                 }
 907
 908                 s = splimp();
 909                 if (IF_QFULL(&ipintrq)) {
 910                         IF_DROP(&ipintrq);
 911                         sc->sc_if.if_ierrors++;
 912                         sc->sc_if.if_iqdrops++;
 913                         m_freem(m);
 914                 } else {
 915                         IF_ENQUEUE(&ipintrq, m);
 916                         schednetisr(NETISR_IP);
 917                 }
 918                 splx(s);
 919                 goto newpack;
 920         }
 921         if (sc->sc_mp < sc->sc_ep) {
 922                 *sc->sc_mp++ = c;
 923                 sc->sc_escape = 0;
 924                 return 0;
 925         }
 926
 927         /* can't put lower; would miss an extra frame */
 928         sc->sc_flags |= SC_ERROR;
 929
 930 error:
 931         sc->sc_if.if_ierrors++;
 932 newpack:
 933         sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX;
 934         sc->sc_escape = 0;
 935         return 0;
 936 }
 937
 938 /*
 939  * Process an ioctl request.
 940  */
 941 static int
 942 slioctl(ifp, cmd, data)
 943         register struct ifnet *ifp;
 944         u_long cmd;
 945         caddr_t data;
 946 {
 947         register struct ifaddr *ifa = (struct ifaddr *)data;
 948         register struct ifreq *ifr = (struct ifreq *)data;
 949         register int s, error = 0;
 950
 951         s = splimp();
 952
 953         switch (cmd) {
 954
 955         case SIOCSIFFLAGS:
 956                 /*
 957                  * if.c will set the interface up even if we
 958                  * don't want it to.
 959                  */
 960                 if (sl_softc[ifp->if_unit].sc_ttyp == NULL) {
 961                         ifp->if_flags &= ~IFF_UP;
 962                 }
 963                 break;
 964         case SIOCSIFADDR:
 965                 /*
 966                  * This is "historical" - set the interface up when
 967                  * setting the address.
 968                  */
 969                 if (ifa->ifa_addr->sa_family == AF_INET) {
 970                         if (sl_softc[ifp->if_unit].sc_ttyp != NULL)
 971                                 if_up(ifp);
 972                 } else {
 973                         error = EAFNOSUPPORT;
 974                 }
 975                 break;
 976
 977         case SIOCSIFDSTADDR:
 978                 if (ifa->ifa_addr->sa_family != AF_INET)
 979                         error = EAFNOSUPPORT;
 980                 break;
 981
 982         case SIOCADDMULTI:
 983         case SIOCDELMULTI:
 984                 break;
 985
 986         case SIOCSIFMTU:
 987                 /*
 988                  * Set the interface MTU.
 989                  */
 990                 if (ifr->ifr_mtu > SLTMAX)
 991                         error = EINVAL;
 992                 else {
 993                         struct tty *tp;
 994
 995                         ifp->if_mtu = ifr->ifr_mtu;
 996                         tp = sl_softc[ifp->if_unit].sc_ttyp;
 997                         if (tp != NULL)
 998                                 clist_alloc_cblocks(&tp->t_outq,
 999                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1,
1000                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1);
1001                 }
1002                 break;
1003
1004         default:
1005                 error = EINVAL;
1006         }
1007         splx(s);
1008         return (error);
1009 }
1010
1011 static void
1012 sl_keepalive(chan)
1013         void *chan;
1014 {
1015         struct sl_softc *sc = chan;
1016
1017         if (sc->sc_keepalive) {
1018                 if (sc->sc_flags & SC_KEEPALIVE)
1019                         pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1);
1020                 else
1021                         sc->sc_flags |= SC_KEEPALIVE;
1022                 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
1023         } else {
1024                 sc->sc_flags &= ~SC_KEEPALIVE;
1025         }
1026 }
1027
1028 static void
1029 sl_outfill(chan)
1030         void *chan;
1031 {
1032         struct sl_softc *sc = chan;
1033         register struct tty *tp = sc->sc_ttyp;
1034         int s;
1035
1036         if (sc->sc_outfill && tp != NULL) {
1037                 if (sc->sc_flags & SC_OUTWAIT) {
1038                         s = splimp ();
1039                         ++sc->sc_if.if_obytes;
1040                         (void) putc(FRAME_END, &tp->t_outq);
1041                         (*tp->t_oproc)(tp);
1042                         splx (s);
1043                 } else
1044                         sc->sc_flags |= SC_OUTWAIT;
1045                 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
1046         } else {
1047                 sc->sc_flags &= ~SC_OUTWAIT;
1048         }
1049 }
1050
1051 #endif