sys/net/sl/if_sl.c

   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 }