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. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      @(#)if_sl.c     8.6 (Berkeley) 2/1/94
  32  * $FreeBSD: src/sys/net/if_sl.c,v 1.84.2.2 2002/02/13 00:43:10 dillon Exp $
  33  */
  34
  35 /*
  36  * Serial Line interface
  37  *
  38  * Rick Adams
  39  * Center for Seismic Studies
  40  * 1300 N 17th Street, Suite 1450
  41  * Arlington, Virginia 22209
  42  * (703)276-7900
  43  * rick@seismo.ARPA
  44  * seismo!rick
  45  *
  46  * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris).
  47  * N.B.: this belongs in netinet, not net, the way it stands now.
  48  * Should have a link-layer type designation, but wouldn't be
  49  * backwards-compatible.
  50  *
  51  * Converted to 4.3BSD Beta by Chris Torek.
  52  * Other changes made at Berkeley, based in part on code by Kirk Smith.
  53  * W. Jolitz added slip abort.
  54  *
  55  * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov).
  56  * Added priority queuing for "interactive" traffic; hooks for TCP
  57  * header compression; ICMP filtering (at 2400 baud, some cretin
  58  * pinging you can use up all your bandwidth).  Made low clist behavior
  59  * more robust and slightly less likely to hang serial line.
  60  * Sped up a bunch of things.
  61  */
  62
  63 #include "use_sl.h"
  64 #include "opt_inet.h"
  65
  66 #include <sys/param.h>
  67 #include <sys/systm.h>
  68 #include <sys/proc.h>
  69 #include <sys/caps.h>
  70 #include <sys/malloc.h>
  71 #include <sys/mbuf.h>
  72 #include <sys/dkstat.h>
  73 #include <sys/socket.h>
  74 #include <sys/sockio.h>
  75 #include <sys/fcntl.h>
  76 #include <sys/signalvar.h>
  77 #include <sys/tty.h>
  78 #include <sys/kernel.h>
  79 #include <sys/sysctl.h>
  80 #include <sys/conf.h>
  81
  82 #include <net/if.h>
  83 #include <net/if_types.h>
  84 #include <net/ifq_var.h>
  85 #include <net/netisr.h>
  86
  87 #if INET
  88 #include <netinet/in.h>
  89 #include <netinet/in_systm.h>
  90 #include <netinet/in_var.h>
  91 #include <netinet/ip.h>
  92 #else
  93 #error "Huh? Slip without inet?"
  94 #endif
  95
  96 #include <net/slcompress.h>
  97 #include "if_slvar.h"
  98 #include <net/slip.h>
  99
 100 #include <net/bpf.h>
 101
 102 static void slattach (void *);
 103 PSEUDO_SET(slattach, if_sl);
 104
 105 /* Set to 0xC002 for broadcast instead of p-to-p */
 106 static int sliffopts = IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
 107 SYSCTL_INT(_net, OID_AUTO, sliffopts, CTLFLAG_RW,
 108            &sliffopts, 0, "");
 109 TUNABLE_INT("net.sliffopts", &sliffopts);
 110
 111 /*
 112  * SLRMAX is a hard limit on input packet size.  To simplify the code
 113  * and improve performance, we require that packets fit in an mbuf
 114  * cluster, and if we get a compressed packet, there's enough extra
 115  * room to expand the header into a max length tcp/ip header (128
 116  * bytes).  So, SLRMAX can be at most
 117  *      MCLBYTES - 128
 118  *
 119  * SLMTU is the default transmit MTU. The transmit MTU should be kept
 120  * small enough so that interactive use doesn't suffer, but large
 121  * enough to provide good performance. 552 is a good choice for SLMTU
 122  * because it is high enough to not fragment TCP packets being routed
 123  * through this host. Packet fragmentation is bad with SLIP because
 124  * fragment headers aren't compressed. The previous assumptions about
 125  * the best MTU value don't really hold when using modern modems with
 126  * BTLZ data compression because the modem buffers play a much larger
 127  * role in interactive performance than the MTU. The MTU can be changed
 128  * at any time to suit the specific environment with ifconfig(8), and
 129  * its maximum value is defined as SLTMAX. SLTMAX must not be so large
 130  * that it would overflow the stack if BPF is configured (XXX; if_ppp.c
 131  * handles this better).
 132  *
 133  * SLIP_HIWAT is the amount of data that will be queued 'downstream'
 134  * of us (i.e., in clists waiting to be picked up by the tty output
 135  * interrupt).  If we queue a lot of data downstream, it's immune to
 136  * our t.o.s. queuing.
 137  * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
 138  * telnet/ftp will see a 1 sec wait, independent of the mtu (the
 139  * wait is dependent on the ftp window size but that's typically
 140  * 1k - 4k).  So, we want SLIP_HIWAT just big enough to amortize
 141  * the cost (in idle time on the wire) of the tty driver running
 142  * off the end of its clists & having to call back slstart for a
 143  * new packet.  For a tty interface with any buffering at all, this
 144  * cost will be zero.  Even with a totally brain dead interface (like
 145  * the one on a typical workstation), the cost will be <= 1 character
 146  * time.  So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
 147  * at most 1% while maintaining good interactive response.
 148  */
 149 #define BUFOFFSET       (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
 150 #define SLRMAX          (MCLBYTES - BUFOFFSET)
 151 #define SLBUFSIZE       (SLRMAX + BUFOFFSET)
 152 #ifndef SLMTU
 153 #define SLMTU           552             /* default MTU */
 154 #endif
 155 #define SLTMAX          1500            /* maximum MTU */
 156 #define SLIP_HIWAT      50
 157 #define CLISTRESERVE    1024            /* Can't let clists get too low */
 158
 159 /*
 160  * SLIP ABORT ESCAPE MECHANISM:
 161  *      (inspired by HAYES modem escape arrangement)
 162  *      1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
 163  *      within window time signals a "soft" exit from slip mode by remote end
 164  *      if the IFF_DEBUG flag is on.
 165  */
 166 #define ABT_ESC         '\033'  /* can't be t_intr - distant host must know it*/
 167 #define ABT_IDLE        1       /* in seconds - idle before an escape */
 168 #define ABT_COUNT       3       /* count of escapes for abort */
 169 #define ABT_WINDOW      (ABT_COUNT*2+2) /* in seconds - time to count */
 170
 171 static struct sl_softc sl_softc[NSL];
 172
 173 #define FRAME_END               0xc0            /* Frame End */
 174 #define FRAME_ESCAPE            0xdb            /* Frame Esc */
 175 #define TRANS_FRAME_END         0xdc            /* transposed frame end */
 176 #define TRANS_FRAME_ESCAPE      0xdd            /* transposed frame esc */
 177
 178 static int slinit (struct sl_softc *);
 179 static struct mbuf *sl_btom (struct sl_softc *, int);
 180 static timeout_t sl_keepalive;
 181 static timeout_t sl_outfill;
 182 static int      slclose (struct tty *,int);
 183 static int      slinput (int, struct tty *);
 184 static int      slioctl (struct ifnet *, u_long, caddr_t, struct ucred *);
 185 static int      sltioctl (struct tty *, u_long, caddr_t, int, struct ucred *);
 186 static int      slopen (cdev_t, struct tty *);
 187 static int      sloutput (struct ifnet *,
 188             struct mbuf *, struct sockaddr *, struct rtentry *);
 189 static int      slstart (struct tty *);
 190
 191 static struct linesw slipdisc = {
 192         slopen,         slclose,        l_noread,       l_nowrite,
 193         sltioctl,       slinput,        slstart,        ttymodem,
 194         FRAME_END
 195 };
 196
 197 /*
 198  * Called from boot code to establish sl interfaces.
 199  */
 200 static void
 201 slattach(void *dummy)
 202 {
 203         struct sl_softc *sc;
 204         int i = 0;
 205
 206         linesw[SLIPDISC] = slipdisc;
 207
 208         for (sc = sl_softc; i < NSL; sc++) {
 209                 if_initname(&(sc->sc_if), "sl", i++);
 210                 sc->sc_if.if_mtu = SLMTU;
 211                 sc->sc_if.if_flags = sliffopts;
 212                 sc->sc_if.if_type = IFT_SLIP;
 213                 sc->sc_if.if_ioctl = slioctl;
 214                 sc->sc_if.if_output = sloutput;
 215                 ifq_set_maxlen(&sc->sc_if.if_snd, 50);
 216                 ifq_set_ready(&sc->sc_if.if_snd);
 217                 sc->sc_fastq.ifq_maxlen = 32;
 218                 sc->sc_if.if_linkmib = sc;
 219                 sc->sc_if.if_linkmiblen = sizeof *sc;
 220                 callout_init_mp(&sc->sc_oftimeout);
 221                 callout_init_mp(&sc->sc_katimeout);
 222                 if_attach(&sc->sc_if, NULL);
 223                 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
 224         }
 225 }
 226
 227 static int
 228 slinit(struct sl_softc *sc)
 229 {
 230         if (sc->sc_ep == NULL)
 231                 sc->sc_ep = kmalloc(SLBUFSIZE, M_DEVBUF, M_WAITOK);
 232         sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX;
 233         sc->sc_mp = sc->sc_buf;
 234         sl_compress_init(&sc->sc_comp, -1);
 235
 236         return (1);
 237 }
 238
 239 /*
 240  * Line specific open routine.
 241  * Attach the given tty to the first available sl unit.
 242  */
 243 /* ARGSUSED */
 244 static int
 245 slopen(cdev_t dev, struct tty *tp)
 246 {
 247         struct sl_softc *sc;
 248         int nsl;
 249         int error;
 250
 251         error = caps_priv_check_self(SYSCAP_RESTRICTEDROOT);
 252         if (error)
 253                 return (error);
 254
 255         lwkt_gettoken(&tty_token);
 256         if (tp->t_line == SLIPDISC) {
 257                 lwkt_reltoken(&tty_token);
 258                 return (0);
 259         }
 260
 261         for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++) {
 262                 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) {
 263                         if (slinit(sc) == 0) {
 264                                 lwkt_reltoken(&tty_token);
 265                                 return (ENOBUFS);
 266                         }
 267                         tp->t_slsc = (caddr_t)sc;
 268                         sc->sc_ttyp = tp;
 269                         sc->sc_if.if_baudrate = tp->t_ospeed;
 270                         ttyflush(tp, FREAD | FWRITE);
 271
 272                         tp->t_line = SLIPDISC;
 273                         /*
 274                          * We don't use t_canq or t_rawq, so reduce their
 275                          * cblock resources to 0.  Reserve enough cblocks
 276                          * for t_outq to guarantee that we can fit a full
 277                          * packet if the SLIP_HIWAT check allows slstart()
 278                          * to loop.  Use the same value for the cblock
 279                          * limit since the reserved blocks should always
 280                          * be enough.  Reserving cblocks probably makes
 281                          * the CLISTRESERVE check unnecessary and wasteful.
 282                          */
 283                         clist_alloc_cblocks(&tp->t_canq, 0);
 284                         clist_alloc_cblocks(&tp->t_outq,
 285                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
 286                         clist_alloc_cblocks(&tp->t_rawq, 0);
 287
 288                         if_up(&sc->sc_if);
 289                         lwkt_reltoken(&tty_token);
 290                         return (0);
 291                 }
 292         }
 293         lwkt_reltoken(&tty_token);
 294
 295         return (ENXIO);
 296 }
 297
 298 /*
 299  * Line specific close routine.
 300  * Detach the tty from the sl unit.
 301  */
 302 static int
 303 slclose(struct tty *tp, int flag)
 304 {
 305         struct sl_softc *sc;
 306
 307         lwkt_gettoken(&tty_token);
 308         lwkt_gettoken(&tp->t_token);
 309         ttyflush(tp, FREAD | FWRITE);
 310
 311         clist_free_cblocks(&tp->t_outq);
 312         tp->t_line = 0;
 313         sc = (struct sl_softc *)tp->t_slsc;
 314         if (sc != NULL) {
 315                 if (sc->sc_outfill) {
 316                         sc->sc_outfill = 0;
 317                         callout_stop(&sc->sc_oftimeout);
 318                 }
 319                 if (sc->sc_keepalive) {
 320                         sc->sc_keepalive = 0;
 321                         callout_stop(&sc->sc_katimeout);
 322                 }
 323                 if_down(&sc->sc_if);
 324                 sc->sc_flags &= SC_STATIC;
 325                 sc->sc_ttyp = NULL;
 326                 tp->t_slsc = NULL;
 327                 if (sc->sc_ep) {
 328                         kfree(sc->sc_ep, M_DEVBUF);
 329                         sc->sc_ep = NULL;
 330                 }
 331                 sc->sc_mp = 0;
 332                 sc->sc_buf = 0;
 333         }
 334         lwkt_reltoken(&tp->t_token);
 335         lwkt_reltoken(&tty_token);
 336
 337         return 0;
 338 }
 339
 340 /*
 341  * Line specific (tty) ioctl routine.
 342  * Provide a way to get the sl unit number.
 343  */
 344 /* ARGSUSED */
 345 static int
 346 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred)
 347 {
 348         struct sl_softc *sc = (struct sl_softc *)tp->t_slsc, *nc, *tmpnc;
 349         int nsl;
 350
 351         lwkt_gettoken(&tty_token);
 352         lwkt_gettoken(&tp->t_token);
 353
 354         switch (cmd) {
 355         case SLIOCGUNIT:
 356                 *(int *)data = sc->sc_if.if_dunit;
 357                 break;
 358
 359         case SLIOCSUNIT:
 360                 if (sc->sc_if.if_dunit != *(u_int *)data) {
 361                         for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) {
 362                                 if (   nc->sc_if.if_dunit == *(u_int *)data
 363                                     && nc->sc_ttyp == NULL
 364                                    ) {
 365                                         tmpnc = kmalloc(sizeof *tmpnc, M_TEMP,
 366                                                        M_WAITOK);
 367                                         *tmpnc = *nc;
 368                                         *nc = *sc;
 369                                         nc->sc_if = tmpnc->sc_if;
 370                                         tmpnc->sc_if = sc->sc_if;
 371                                         *sc = *tmpnc;
 372                                         kfree(tmpnc, M_TEMP);
 373                                         if (sc->sc_if.if_flags & IFF_UP) {
 374                                                 if_down(&sc->sc_if);
 375                                                 if (!(nc->sc_if.if_flags & IFF_UP))
 376                                                         if_up(&nc->sc_if);
 377                                         } else if (nc->sc_if.if_flags & IFF_UP)
 378                                                 if_down(&nc->sc_if);
 379                                         sc->sc_flags &= ~SC_STATIC;
 380                                         sc->sc_flags |= (nc->sc_flags & SC_STATIC);
 381                                         tp->t_slsc = sc = nc;
 382                                         clist_alloc_cblocks(&tp->t_outq,
 383                                             SLIP_HIWAT +
 384                                             2 * sc->sc_if.if_mtu + 1);
 385                                         sl_compress_init(&sc->sc_comp, -1);
 386                                         goto slfound;
 387                                 }
 388                         }
 389                         lwkt_reltoken(&tp->t_token);
 390                         lwkt_reltoken(&tty_token);
 391                         return (ENXIO);
 392                 }
 393         slfound:
 394                 sc->sc_flags |= SC_STATIC;
 395                 break;
 396
 397         case SLIOCSKEEPAL:
 398                 sc->sc_keepalive = *(u_int *)data * hz;
 399                 if (sc->sc_keepalive) {
 400                         sc->sc_flags |= SC_KEEPALIVE;
 401                         callout_reset(&sc->sc_katimeout, sc->sc_keepalive,
 402                                         sl_keepalive, sc);
 403                 } else {
 404                         if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
 405                                 callout_stop(&sc->sc_katimeout);
 406                                 sc->sc_flags &= ~SC_KEEPALIVE;
 407                         }
 408                 }
 409                 break;
 410
 411         case SLIOCGKEEPAL:
 412                 *(int *)data = sc->sc_keepalive / hz;
 413                 break;
 414
 415         case SLIOCSOUTFILL:
 416                 sc->sc_outfill = *(u_int *)data * hz;
 417                 if (sc->sc_outfill) {
 418                         sc->sc_flags |= SC_OUTWAIT;
 419                         callout_reset(&sc->sc_oftimeout, sc->sc_outfill,
 420                                         sl_outfill, sc);
 421                 } else {
 422                         if ((sc->sc_flags & SC_OUTWAIT) != 0) {
 423                                 callout_stop(&sc->sc_oftimeout);
 424                                 sc->sc_flags &= ~SC_OUTWAIT;
 425                         }
 426                 }
 427                 break;
 428
 429         case SLIOCGOUTFILL:
 430                 *(int *)data = sc->sc_outfill / hz;
 431                 break;
 432
 433         default:
 434                 lwkt_reltoken(&tp->t_token);
 435                 lwkt_reltoken(&tty_token);
 436                 return (ENOIOCTL);
 437         }
 438         lwkt_reltoken(&tp->t_token);
 439         lwkt_reltoken(&tty_token);
 440
 441         return (0);
 442 }
 443
 444 /*
 445  * Queue a packet.  Start transmission if not active.
 446  * Compression happens in slstart; if we do it here, IP TOS
 447  * will cause us to not compress "background" packets, because
 448  * ordering gets trashed.  It can be done for all packets in slstart.
 449  */
 450 static int
 451 sloutput_serialized(struct ifnet *ifp, struct ifaltq_subque *ifsq,
 452     struct mbuf *m, struct sockaddr *dst, struct rtentry *rtp)
 453 {
 454         struct sl_softc *sc = &sl_softc[ifp->if_dunit];
 455         struct ip *ip;
 456         int error;
 457         struct altq_pktattr pktattr;
 458
 459         ifq_classify(&ifp->if_snd, m, dst->sa_family, &pktattr);
 460
 461         /*
 462          * `Cannot happen' (see slioctl).  Someday we will extend
 463          * the line protocol to support other address families.
 464          */
 465         if (dst->sa_family != AF_INET) {
 466                 kprintf("%s: af%d not supported\n", sc->sc_if.if_xname,
 467                         dst->sa_family);
 468                 m_freem(m);
 469                 IFNET_STAT_INC(&sc->sc_if, noproto, 1);
 470                 return (EAFNOSUPPORT);
 471         }
 472
 473         if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
 474                 m_freem(m);
 475                 return (ENETDOWN);
 476         }
 477         if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
 478                 m_freem(m);
 479                 return (EHOSTUNREACH);
 480         }
 481         ip = mtod(m, struct ip *);
 482         if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
 483                 m_freem(m);
 484                 return (ENETRESET);             /* XXX ? */
 485         }
 486
 487         if ((ip->ip_tos & IPTOS_LOWDELAY) &&
 488             !ifq_is_enabled(&sc->sc_if.if_snd)) {
 489                 if (IF_QFULL(&sc->sc_fastq)) {
 490                         IF_DROP(&sc->sc_fastq);
 491                         m_freem(m);
 492                         error = ENOBUFS;
 493                 } else {
 494                         IF_ENQUEUE(&sc->sc_fastq, m);
 495                         error = 0;
 496                 }
 497         } else {
 498                 error = ifsq_enqueue(ifsq, m, &pktattr);
 499         }
 500         if (error) {
 501                 IFNET_STAT_INC(&sc->sc_if, oqdrops, 1);
 502                 return (error);
 503         }
 504         if (sc->sc_ttyp->t_outq.c_cc == 0)
 505                 slstart(sc->sc_ttyp);
 506         return (0);
 507 }
 508
 509 static int
 510 sloutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 511          struct rtentry *rtp)
 512 {
 513         struct ifaltq_subque *ifsq = ifq_get_subq_default(&ifp->if_snd);
 514         int error;
 515
 516         ifsq_serialize_hw(ifsq);
 517         error = sloutput_serialized(ifp, ifsq, m, dst, rtp);
 518         ifsq_deserialize_hw(ifsq);
 519
 520         return error;
 521 }
 522
 523 /*
 524  * Start output on interface.  Get another datagram
 525  * to send from the interface queue and map it to
 526  * the interface before starting output.
 527  */
 528 static int
 529 slstart(struct tty *tp)
 530 {
 531         struct sl_softc *sc = (struct sl_softc *)tp->t_slsc;
 532         struct ifaltq_subque *ifsq = ifq_get_subq_default(&sc->sc_if.if_snd);
 533         struct mbuf *m;
 534         u_char *cp;
 535         struct ip *ip;
 536         u_char bpfbuf[SLTMAX + SLIP_HDRLEN];
 537         int len = 0;
 538
 539         lwkt_gettoken(&tp->t_token);
 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                                 lwkt_reltoken(&tp->t_token);
 553                                 return 0;
 554                         }
 555                 }
 556
 557                 /*
 558                  * This happens briefly when the line shuts down.
 559                  */
 560                 if (sc == NULL) {
 561                         lwkt_reltoken(&tp->t_token);
 562                         return 0;
 563                 }
 564
 565                 /*
 566                  * Get a packet and send it to the interface.
 567                  */
 568                 IF_DEQUEUE(&sc->sc_fastq, m);
 569                 if (m)
 570                         IFNET_STAT_INC(&sc->sc_if, omcasts, 1); /* XXX */
 571                 else
 572                         m = ifsq_dequeue(ifsq);
 573                 if (m == NULL) {
 574                         lwkt_reltoken(&tp->t_token);
 575                         return 0;
 576                 }
 577
 578                 /*
 579                  * We do the header compression here rather than in sloutput
 580                  * because the packets will be out of order if we are using TOS
 581                  * queueing, and the connection id compression will get
 582                  * munged when this happens.
 583                  */
 584                 if (sc->sc_if.if_bpf) {
 585                         /*
 586                          * We need to save the TCP/IP header before it's
 587                          * compressed.  To avoid complicated code, we just
 588                          * copy the entire packet into a stack buffer (since
 589                          * this is a serial line, packets should be short
 590                          * and/or the copy should be negligible cost compared
 591                          * to the packet transmission time).
 592                          */
 593                         struct mbuf *m1 = m;
 594                         u_char *cp = bpfbuf + SLIP_HDRLEN;
 595
 596                         len = 0;
 597                         do {
 598                                 int mlen = m1->m_len;
 599
 600                                 bcopy(mtod(m1, caddr_t), cp, mlen);
 601                                 cp += mlen;
 602                                 len += mlen;
 603                         } while ((m1 = m1->m_next) != NULL);
 604                 }
 605                 ip = mtod(m, struct ip *);
 606                 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
 607                         if (sc->sc_if.if_flags & SC_COMPRESS)
 608                                 *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
 609                                     &sc->sc_comp, 1);
 610                 }
 611                 if (sc->sc_if.if_bpf) {
 612                         bpf_gettoken();
 613
 614                         if (sc->sc_if.if_bpf) {
 615                                 /*
 616                                  * Put the SLIP pseudo-"link header" in place.
 617                                  * The compressed header is now at the
 618                                  * beginning of the mbuf.
 619                                  */
 620                                 bpfbuf[SLX_DIR] = SLIPDIR_OUT;
 621                                 bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR],
 622                                     CHDR_LEN);
 623                                 bpf_tap(sc->sc_if.if_bpf, bpfbuf,
 624                                     len + SLIP_HDRLEN);
 625                         }
 626
 627                         bpf_reltoken();
 628                 }
 629
 630                 sc->sc_flags &= ~SC_OUTWAIT;
 631
 632                 /*
 633                  * The extra FRAME_END will start up a new packet, and thus
 634                  * will flush any accumulated garbage.  We do this whenever
 635                  * the line may have been idle for some time.
 636                  */
 637                 if (tp->t_outq.c_cc == 0) {
 638                         IFNET_STAT_INC(&sc->sc_if, obytes, 1);
 639                         clist_putc(FRAME_END, &tp->t_outq);
 640                 }
 641
 642                 while (m) {
 643                         u_char *ep;
 644
 645                         cp = mtod(m, u_char *); ep = cp + m->m_len;
 646                         while (cp < ep) {
 647                                 /*
 648                                  * Find out how many bytes in the string we can
 649                                  * handle without doing something special.
 650                                  */
 651                                 u_char *bp = cp;
 652
 653                                 while (cp < ep) {
 654                                         switch (*cp++) {
 655                                         case FRAME_ESCAPE:
 656                                         case FRAME_END:
 657                                                 --cp;
 658                                                 goto out;
 659                                         }
 660                                 }
 661                                 out:
 662                                 if (cp > bp) {
 663                                         /*
 664                                          * Put n characters at once
 665                                          * into the tty output queue.
 666                                          */
 667                                         if (clist_btoq((char *)bp, cp - bp,
 668                                                        &tp->t_outq)) {
 669                                                 break;
 670                                         }
 671                                         IFNET_STAT_INC(&sc->sc_if, obytes,
 672                                                        cp - bp);
 673                                 }
 674                                 /*
 675                                  * If there are characters left in the mbuf,
 676                                  * the first one must be special..
 677                                  * Put it out in a different form.
 678                                  */
 679                                 if (cp < ep) {
 680                                         if (clist_putc(FRAME_ESCAPE, &tp->t_outq))
 681                                                 break;
 682                                         if (clist_putc(*cp++ == FRAME_ESCAPE ?
 683                                            TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
 684                                            &tp->t_outq)) {
 685                                                 clist_unputc(&tp->t_outq);
 686                                                 break;
 687                                         }
 688                                         IFNET_STAT_INC(&sc->sc_if, obytes, 2);
 689                                 }
 690                         }
 691                         m = m_free(m);
 692                 }
 693
 694                 if (clist_putc(FRAME_END, &tp->t_outq)) {
 695                         /*
 696                          * Not enough room.  Remove a char to make room
 697                          * and end the packet normally.
 698                          * If you get many collisions (more than one or two
 699                          * a day) you probably do not have enough clists
 700                          * and you should increase "nclist" in param.c.
 701                          */
 702                         clist_unputc(&tp->t_outq);
 703                         clist_putc(FRAME_END, &tp->t_outq);
 704                         IFNET_STAT_INC(&sc->sc_if, collisions, 1);
 705                 } else {
 706                         IFNET_STAT_INC(&sc->sc_if, obytes, 1);
 707                         IFNET_STAT_INC(&sc->sc_if, opackets, 1);
 708                 }
 709         }
 710         lwkt_reltoken(&tp->t_token);
 711
 712         return 0;
 713 }
 714
 715 /*
 716  * Copy data buffer to mbuf chain; add ifnet pointer.
 717  */
 718 static struct mbuf *
 719 sl_btom(struct sl_softc *sc, int len)
 720 {
 721         struct mbuf *m;
 722
 723         if (len >= MCLBYTES)
 724                 return (NULL);
 725
 726         MGETHDR(m, M_NOWAIT, MT_DATA);
 727         if (m == NULL)
 728                 return (NULL);
 729
 730         /*
 731          * If we have more than MHLEN bytes, it's cheaper to
 732          * queue the cluster we just filled & allocate a new one
 733          * for the input buffer.  Otherwise, fill the mbuf we
 734          * allocated above.  Note that code in the input routine
 735          * guarantees that packet will fit in a cluster.
 736          */
 737         if (len >= MHLEN) {
 738                 MCLGET(m, M_NOWAIT);
 739                 if ((m->m_flags & M_EXT) == 0) {
 740                         /*
 741                          * we couldn't get a cluster - if memory's this
 742                          * low, it's time to start dropping packets.
 743                          */
 744                         m_free(m);
 745                         return (NULL);
 746                 }
 747         }
 748         bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
 749         m->m_len = len;
 750         m->m_pkthdr.len = len;
 751         m->m_pkthdr.rcvif = &sc->sc_if;
 752         return (m);
 753 }
 754
 755 /*
 756  * tty interface receiver interrupt.
 757  */
 758 static int
 759 slinput(int c, struct tty *tp)
 760 {
 761         struct sl_softc *sc;
 762         struct mbuf *m;
 763         int len;
 764         u_char chdr[CHDR_LEN];
 765
 766 #if 0
 767         kprintf(" %02x", (unsigned char)c);
 768         if ((unsigned char)c == 0xC0)
 769                 kprintf("\n");
 770 #endif
 771
 772         lwkt_gettoken(&tp->t_token);
 773         tk_nin++;
 774         sc = (struct sl_softc *)tp->t_slsc;
 775         if (sc == NULL) {
 776                 lwkt_reltoken(&tp->t_token);
 777 #if 0
 778                 kprintf("X");
 779 #endif
 780                 return 0;
 781         }
 782         if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
 783                 sc->sc_flags |= SC_ERROR;
 784                 lwkt_reltoken(&tp->t_token);
 785 #if 0
 786                 kprintf("Y");
 787 #endif
 788                 return 0;
 789         }
 790         c &= TTY_CHARMASK;
 791
 792         IFNET_STAT_INC(&sc->sc_if, ibytes, 1);
 793
 794         if (sc->sc_if.if_flags & IFF_DEBUG) {
 795                 if (c == ABT_ESC) {
 796                         /*
 797                          * If we have a previous abort, see whether
 798                          * this one is within the time limit.
 799                          */
 800                         if (sc->sc_abortcount &&
 801                             time_uptime >= sc->sc_starttime + ABT_WINDOW)
 802                                 sc->sc_abortcount = 0;
 803                         /*
 804                          * If we see an abort after "idle" time, count it;
 805                          * record when the first abort escape arrived.
 806                          */
 807                         if (time_uptime >= sc->sc_lasttime + ABT_IDLE) {
 808                                 if (++sc->sc_abortcount == 1)
 809                                         sc->sc_starttime = time_uptime;
 810                                 if (sc->sc_abortcount >= ABT_COUNT) {
 811                                         slclose(tp,0);
 812                                         lwkt_reltoken(&tp->t_token);
 813                                         return 0;
 814                                 }
 815                         }
 816                 } else
 817                         sc->sc_abortcount = 0;
 818                 sc->sc_lasttime = time_uptime;
 819         }
 820
 821         switch (c) {
 822
 823         case TRANS_FRAME_ESCAPE:
 824                 if (sc->sc_escape)
 825                         c = FRAME_ESCAPE;
 826                 break;
 827
 828         case TRANS_FRAME_END:
 829                 if (sc->sc_escape)
 830                         c = FRAME_END;
 831                 break;
 832
 833         case FRAME_ESCAPE:
 834                 sc->sc_escape = 1;
 835                 lwkt_reltoken(&tp->t_token);
 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                         bpf_gettoken();
 890
 891                         if (sc->sc_if.if_bpf) {
 892                                 /*
 893                                  * Put the SLIP pseudo-"link header" in place.
 894                                  * We couldn't do this any earlier since
 895                                  * decompression probably moved the buffer
 896                                  * pointer.  Then, invoke BPF.
 897                                  */
 898                                 u_char *hp = sc->sc_buf - SLIP_HDRLEN;
 899
 900                                 hp[SLX_DIR] = SLIPDIR_IN;
 901                                 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
 902                                 bpf_tap(sc->sc_if.if_bpf, hp,
 903                                     len + SLIP_HDRLEN);
 904                         }
 905
 906                         bpf_reltoken();
 907                 }
 908                 m = sl_btom(sc, len);
 909                 if (m == NULL)
 910                         goto error;
 911
 912                 IFNET_STAT_INC(&sc->sc_if, ipackets, 1);
 913
 914                 if ((sc->sc_if.if_flags & IFF_UP) == 0) {
 915                         m_freem(m);
 916                         goto newpack;
 917                 }
 918
 919                 if (netisr_queue(NETISR_IP, m)) {
 920                         IFNET_STAT_INC(&sc->sc_if, ierrors, 1);
 921                         IFNET_STAT_INC(&sc->sc_if, iqdrops, 1);
 922                 }
 923
 924                 goto newpack;
 925         }
 926         if (sc->sc_mp < sc->sc_ep + SLBUFSIZE) {
 927                 *sc->sc_mp++ = c;
 928                 sc->sc_escape = 0;
 929                 lwkt_reltoken(&tp->t_token);
 930                 return 0;
 931         }
 932
 933         /* can't put lower; would miss an extra frame */
 934         sc->sc_flags |= SC_ERROR;
 935
 936 error:
 937         IFNET_STAT_INC(&sc->sc_if, ierrors, 1);
 938 newpack:
 939         sc->sc_mp = sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX;
 940         sc->sc_escape = 0;
 941         lwkt_reltoken(&tp->t_token);
 942
 943         return 0;
 944 }
 945
 946 /*
 947  * Process an ioctl request.
 948  */
 949 static int
 950 slioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 951 {
 952         struct ifaddr *ifa = (struct ifaddr *)data;
 953         struct ifreq *ifr = (struct ifreq *)data;
 954         int error = 0;
 955
 956         switch (cmd) {
 957
 958         case SIOCSIFFLAGS:
 959                 /*
 960                  * if.c will set the interface up even if we
 961                  * don't want it to.
 962                  */
 963                 if (sl_softc[ifp->if_dunit].sc_ttyp == NULL) {
 964                         ifp->if_flags &= ~IFF_UP;
 965                 }
 966                 break;
 967         case SIOCSIFADDR:
 968                 /*
 969                  * This is "historical" - set the interface up when
 970                  * setting the address.
 971                  */
 972                 if (ifa->ifa_addr->sa_family == AF_INET) {
 973                         if (sl_softc[ifp->if_dunit].sc_ttyp != NULL)
 974                                 ifp->if_flags |= IFF_UP;
 975                 } else {
 976                         error = EAFNOSUPPORT;
 977                 }
 978                 break;
 979
 980         case SIOCSIFDSTADDR:
 981                 if (ifa->ifa_addr->sa_family != AF_INET)
 982                         error = EAFNOSUPPORT;
 983                 break;
 984
 985         case SIOCADDMULTI:
 986         case SIOCDELMULTI:
 987                 break;
 988
 989         case SIOCSIFMTU:
 990                 /*
 991                  * Set the interface MTU.
 992                  */
 993                 if (ifr->ifr_mtu > SLTMAX)
 994                         error = EINVAL;
 995                 else {
 996                         struct tty *tp;
 997
 998                         ifp->if_mtu = ifr->ifr_mtu;
 999                         tp = sl_softc[ifp->if_dunit].sc_ttyp;
1000                         if (tp != NULL)
1001                                 clist_alloc_cblocks(&tp->t_outq,
1002                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1);
1003                 }
1004                 break;
1005
1006         default:
1007                 error = EINVAL;
1008         }
1009         return (error);
1010 }
1011
1012 static void
1013 sl_keepalive(void *chan)
1014 {
1015         struct sl_softc *sc = chan;
1016         struct tty *tp = sc->sc_ttyp;
1017         struct pgrp *pg;
1018
1019         lwkt_gettoken(&tp->t_token);
1020         if (sc->sc_keepalive) {
1021                 if (sc->sc_flags & SC_KEEPALIVE) {
1022                         pg = sc->sc_ttyp->t_pgrp;
1023                         if (pg) {
1024                                 pgref(pg);
1025                                 pgsignal (pg, SIGURG, 1);
1026                                 pgrel(pg);
1027                         }
1028                 } else {
1029                         sc->sc_flags |= SC_KEEPALIVE;
1030                 }
1031                 callout_reset(&sc->sc_katimeout, sc->sc_keepalive,
1032                                 sl_keepalive, sc);
1033         } else {
1034                 sc->sc_flags &= ~SC_KEEPALIVE;
1035         }
1036         lwkt_reltoken(&tp->t_token);
1037 }
1038
1039 static void
1040 sl_outfill(void *chan)
1041 {
1042         struct sl_softc *sc = chan;
1043         struct tty *tp = sc->sc_ttyp;
1044
1045         lwkt_gettoken(&tp->t_token);
1046
1047         if (sc->sc_outfill && tp != NULL) {
1048                 if (sc->sc_flags & SC_OUTWAIT) {
1049                         IFNET_STAT_INC(&sc->sc_if, obytes, 1);
1050                         clist_putc(FRAME_END, &tp->t_outq);
1051                         (*tp->t_oproc)(tp);
1052                 } else
1053                         sc->sc_flags |= SC_OUTWAIT;
1054                 callout_reset(&sc->sc_oftimeout, sc->sc_outfill,
1055                                 sl_outfill, sc);
1056         } else {
1057                 sc->sc_flags &= ~SC_OUTWAIT;
1058         }
1059         lwkt_reltoken(&tp->t_token);
1060 }
1061
1062 MODULE_VERSION(if_sl, 1);