proc->thread stage 4: rework the VFS and DEVICE subsystems to take thread
[dragonfly.git] / sys / net / sl / if_sl.c
1 /*
2  * Copyright (c) 1987, 1989, 1992, 1993
3  *      The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *      This product includes software developed by the University of
16  *      California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *      @(#)if_sl.c     8.6 (Berkeley) 2/1/94
34  * $FreeBSD: src/sys/net/if_sl.c,v 1.84.2.2 2002/02/13 00:43:10 dillon Exp $
35  * $DragonFly: src/sys/net/sl/if_sl.c,v 1.4 2003/06/25 03:56:02 dillon Exp $
36  */
37
38 /*
39  * Serial Line interface
40  *
41  * Rick Adams
42  * Center for Seismic Studies
43  * 1300 N 17th Street, Suite 1450
44  * Arlington, Virginia 22209
45  * (703)276-7900
46  * rick@seismo.ARPA
47  * seismo!rick
48  *
49  * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris).
50  * N.B.: this belongs in netinet, not net, the way it stands now.
51  * Should have a link-layer type designation, but wouldn't be
52  * backwards-compatible.
53  *
54  * Converted to 4.3BSD Beta by Chris Torek.
55  * Other changes made at Berkeley, based in part on code by Kirk Smith.
56  * W. Jolitz added slip abort.
57  *
58  * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov).
59  * Added priority queuing for "interactive" traffic; hooks for TCP
60  * header compression; ICMP filtering (at 2400 baud, some cretin
61  * pinging you can use up all your bandwidth).  Made low clist behavior
62  * more robust and slightly less likely to hang serial line.
63  * Sped up a bunch of things.
64  *
65  * Note that splimp() is used throughout to block both (tty) input
66  * interrupts and network activity; thus, splimp must be >= spltty.
67  */
68
69 #include "sl.h"
70
71 #include "opt_inet.h"
72 #if !defined(KLD_MODULE)
73 #include "opt_slip.h"
74 #endif
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/proc.h>
78 #include <sys/malloc.h>
79 #include <sys/mbuf.h>
80 #include <sys/dkstat.h>
81 #include <sys/socket.h>
82 #include <sys/sockio.h>
83 #include <sys/fcntl.h>
84 #include <sys/signalvar.h>
85 #include <sys/tty.h>
86 #include <sys/clist.h>
87 #include <sys/kernel.h>
88 #include <sys/conf.h>
89
90 #include <net/if.h>
91 #include <net/if_types.h>
92 #include <net/netisr.h>
93
94 #if INET
95 #include <netinet/in.h>
96 #include <netinet/in_systm.h>
97 #include <netinet/in_var.h>
98 #include <netinet/ip.h>
99 #else
100 #error "Huh? Slip without inet?"
101 #endif
102
103 #include <net/slcompress.h>
104 #include <net/if_slvar.h>
105 #include <net/slip.h>
106
107 #include <net/bpf.h>
108
109 #ifdef __i386__
110 #include <i386/isa/intr_machdep.h>
111 #endif
112
113 static void slattach __P((void *));
114 PSEUDO_SET(slattach, if_sl);
115
116 /*
117  * SLRMAX is a hard limit on input packet size.  To simplify the code
118  * and improve performance, we require that packets fit in an mbuf
119  * cluster, and if we get a compressed packet, there's enough extra
120  * room to expand the header into a max length tcp/ip header (128
121  * bytes).  So, SLRMAX can be at most
122  *      MCLBYTES - 128
123  *
124  * SLMTU is the default transmit MTU. The transmit MTU should be kept
125  * small enough so that interactive use doesn't suffer, but large
126  * enough to provide good performance. 552 is a good choice for SLMTU
127  * because it is high enough to not fragment TCP packets being routed
128  * through this host. Packet fragmentation is bad with SLIP because
129  * fragment headers aren't compressed. The previous assumptions about
130  * the best MTU value don't really hold when using modern modems with
131  * BTLZ data compression because the modem buffers play a much larger
132  * role in interactive performance than the MTU. The MTU can be changed
133  * at any time to suit the specific environment with ifconfig(8), and
134  * its maximum value is defined as SLTMAX. SLTMAX must not be so large
135  * that it would overflow the stack if BPF is configured (XXX; if_ppp.c
136  * handles this better).
137  *
138  * SLIP_HIWAT is the amount of data that will be queued 'downstream'
139  * of us (i.e., in clists waiting to be picked up by the tty output
140  * interrupt).  If we queue a lot of data downstream, it's immune to
141  * our t.o.s. queuing.
142  * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
143  * telnet/ftp will see a 1 sec wait, independent of the mtu (the
144  * wait is dependent on the ftp window size but that's typically
145  * 1k - 4k).  So, we want SLIP_HIWAT just big enough to amortize
146  * the cost (in idle time on the wire) of the tty driver running
147  * off the end of its clists & having to call back slstart for a
148  * new packet.  For a tty interface with any buffering at all, this
149  * cost will be zero.  Even with a totally brain dead interface (like
150  * the one on a typical workstation), the cost will be <= 1 character
151  * time.  So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
152  * at most 1% while maintaining good interactive response.
153  */
154 #define BUFOFFSET       (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
155 #define SLRMAX          (MCLBYTES - BUFOFFSET)
156 #define SLBUFSIZE       (SLRMAX + BUFOFFSET)
157 #ifndef SLMTU
158 #define SLMTU           552             /* default MTU */
159 #endif
160 #define SLTMAX          1500            /* maximum MTU */
161 #define SLIP_HIWAT      roundup(50,CBSIZE)
162 #define CLISTRESERVE    1024            /* Can't let clists get too low */
163
164 /*
165  * SLIP ABORT ESCAPE MECHANISM:
166  *      (inspired by HAYES modem escape arrangement)
167  *      1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
168  *      within window time signals a "soft" exit from slip mode by remote end
169  *      if the IFF_DEBUG flag is on.
170  */
171 #define ABT_ESC         '\033'  /* can't be t_intr - distant host must know it*/
172 #define ABT_IDLE        1       /* in seconds - idle before an escape */
173 #define ABT_COUNT       3       /* count of escapes for abort */
174 #define ABT_WINDOW      (ABT_COUNT*2+2) /* in seconds - time to count */
175
176 static struct sl_softc sl_softc[NSL];
177
178 #define FRAME_END               0xc0            /* Frame End */
179 #define FRAME_ESCAPE            0xdb            /* Frame Esc */
180 #define TRANS_FRAME_END         0xdc            /* transposed frame end */
181 #define TRANS_FRAME_ESCAPE      0xdd            /* transposed frame esc */
182
183 static int slinit __P((struct sl_softc *));
184 static struct mbuf *sl_btom __P((struct sl_softc *, int));
185 static timeout_t sl_keepalive;
186 static timeout_t sl_outfill;
187 static int      slclose __P((struct tty *,int));
188 static int      slinput __P((int, struct tty *));
189 static int      slioctl __P((struct ifnet *, u_long, caddr_t));
190 static int      sltioctl __P((struct tty *, u_long, caddr_t, int, struct thread *));
191 static int      slopen __P((dev_t, struct tty *));
192 static int      sloutput __P((struct ifnet *,
193             struct mbuf *, struct sockaddr *, struct rtentry *));
194 static int      slstart __P((struct tty *));
195
196 static struct linesw slipdisc = {
197         slopen,         slclose,        l_noread,       l_nowrite,
198         sltioctl,       slinput,        slstart,        ttymodem,
199         FRAME_END
200 };
201
202 /*
203  * Called from boot code to establish sl interfaces.
204  */
205 static void
206 slattach(dummy)
207         void *dummy;
208 {
209         register struct sl_softc *sc;
210         register int i = 0;
211
212         linesw[SLIPDISC] = slipdisc;
213
214         for (sc = sl_softc; i < NSL; sc++) {
215                 sc->sc_if.if_name = "sl";
216                 sc->sc_if.if_unit = i++;
217                 sc->sc_if.if_mtu = SLMTU;
218                 sc->sc_if.if_flags =
219 #ifdef SLIP_IFF_OPTS
220                     SLIP_IFF_OPTS;
221 #else
222                     IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
223 #endif
224                 sc->sc_if.if_type = IFT_SLIP;
225                 sc->sc_if.if_ioctl = slioctl;
226                 sc->sc_if.if_output = sloutput;
227                 sc->sc_if.if_snd.ifq_maxlen = 50;
228                 sc->sc_fastq.ifq_maxlen = 32;
229                 sc->sc_if.if_linkmib = sc;
230                 sc->sc_if.if_linkmiblen = sizeof *sc;
231                 if_attach(&sc->sc_if);
232                 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
233         }
234 }
235
236 static int
237 slinit(sc)
238         register struct sl_softc *sc;
239 {
240         register caddr_t p;
241
242 #ifdef __i386__
243         int s;
244
245         s = splhigh();
246         tty_imask |= net_imask;
247         net_imask = tty_imask;
248         update_intr_masks();
249         splx(s);
250         if (bootverbose)
251                 printf("new imasks: bio %x, tty %x, net %x\n",
252                     bio_imask, tty_imask, net_imask);
253 #endif
254         if (sc->sc_ep == (u_char *) 0) {
255                 MCLALLOC(p, M_WAIT);
256                 if (p)
257                         sc->sc_ep = (u_char *)p + SLBUFSIZE;
258                 else {
259                         printf("sl%ld: can't allocate buffer\n",
260                             (long)(sc - sl_softc));
261                         return (0);
262                 }
263         }
264         sc->sc_buf = sc->sc_ep - SLRMAX;
265         sc->sc_mp = sc->sc_buf;
266         sl_compress_init(&sc->sc_comp, -1);
267         return (1);
268 }
269
270 /*
271  * Line specific open routine.
272  * Attach the given tty to the first available sl unit.
273  */
274 /* ARGSUSED */
275 static int
276 slopen(dev_t dev, struct tty *tp)
277 {
278         struct sl_softc *sc;
279         int nsl;
280         int s, error;
281         struct thread *td = curthread;  /* XXX */
282
283         error = suser(td);
284         if (error)
285                 return (error);
286
287         if (tp->t_line == SLIPDISC)
288                 return (0);
289
290         for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++)
291                 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) {
292                         if (slinit(sc) == 0)
293                                 return (ENOBUFS);
294                         tp->t_sc = (caddr_t)sc;
295                         sc->sc_ttyp = tp;
296                         sc->sc_if.if_baudrate = tp->t_ospeed;
297                         ttyflush(tp, FREAD | FWRITE);
298
299                         tp->t_line = SLIPDISC;
300                         /*
301                          * We don't use t_canq or t_rawq, so reduce their
302                          * cblock resources to 0.  Reserve enough cblocks
303                          * for t_outq to guarantee that we can fit a full
304                          * packet if the SLIP_HIWAT check allows slstart()
305                          * to loop.  Use the same value for the cblock
306                          * limit since the reserved blocks should always
307                          * be enough.  Reserving cblocks probably makes
308                          * the CLISTRESERVE check unnecessary and wasteful.
309                          */
310                         clist_alloc_cblocks(&tp->t_canq, 0, 0);
311                         clist_alloc_cblocks(&tp->t_outq,
312                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
313                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
314                         clist_alloc_cblocks(&tp->t_rawq, 0, 0);
315
316                         s = splnet();
317                         if_up(&sc->sc_if);
318                         splx(s);
319                         return (0);
320                 }
321         return (ENXIO);
322 }
323
324 /*
325  * Line specific close routine.
326  * Detach the tty from the sl unit.
327  */
328 static int
329 slclose(tp,flag)
330         struct tty *tp;
331         int flag;
332 {
333         register struct sl_softc *sc;
334         int s;
335
336         ttyflush(tp, FREAD | FWRITE);
337         /*
338          * XXX the placement of the following spl is misleading.  tty
339          * interrupts must be blocked across line discipline switches
340          * and throughout closes to avoid races.
341          */
342         s = splimp();           /* actually, max(spltty, splnet) */
343         clist_free_cblocks(&tp->t_outq);
344         tp->t_line = 0;
345         sc = (struct sl_softc *)tp->t_sc;
346         if (sc != NULL) {
347                 if (sc->sc_outfill) {
348                         sc->sc_outfill = 0;
349                         untimeout(sl_outfill, sc, sc->sc_ofhandle);
350                 }
351                 if (sc->sc_keepalive) {
352                         sc->sc_keepalive = 0;
353                         untimeout(sl_keepalive, sc, sc->sc_kahandle);
354                 }
355                 if_down(&sc->sc_if);
356                 sc->sc_flags &= SC_STATIC;
357                 sc->sc_ttyp = NULL;
358                 tp->t_sc = NULL;
359                 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE));
360                 sc->sc_ep = 0;
361                 sc->sc_mp = 0;
362                 sc->sc_buf = 0;
363         }
364         splx(s);
365         return 0;
366 }
367
368 /*
369  * Line specific (tty) ioctl routine.
370  * Provide a way to get the sl unit number.
371  */
372 /* ARGSUSED */
373 static int
374 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct thread *p)
375 {
376         struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc;
377         int s, nsl;
378
379         s = splimp();
380         switch (cmd) {
381         case SLIOCGUNIT:
382                 *(int *)data = sc->sc_if.if_unit;
383                 break;
384
385         case SLIOCSUNIT:
386                 if (sc->sc_if.if_unit != *(u_int *)data) {
387                         for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) {
388                                 if (   nc->sc_if.if_unit == *(u_int *)data
389                                     && nc->sc_ttyp == NULL
390                                    ) {
391                                         tmpnc = malloc(sizeof *tmpnc, M_TEMP,
392                                                        M_NOWAIT);
393                                         if (tmpnc == NULL) {
394                                                 splx(s);
395                                                 return (ENOMEM);
396                                         }
397                                         *tmpnc = *nc;
398                                         *nc = *sc;
399                                         nc->sc_if = tmpnc->sc_if;
400                                         tmpnc->sc_if = sc->sc_if;
401                                         *sc = *tmpnc;
402                                         free(tmpnc, M_TEMP);
403                                         if (sc->sc_if.if_flags & IFF_UP) {
404                                                 if_down(&sc->sc_if);
405                                                 if (!(nc->sc_if.if_flags & IFF_UP))
406                                                         if_up(&nc->sc_if);
407                                         } else if (nc->sc_if.if_flags & IFF_UP)
408                                                 if_down(&nc->sc_if);
409                                         sc->sc_flags &= ~SC_STATIC;
410                                         sc->sc_flags |= (nc->sc_flags & SC_STATIC);
411                                         tp->t_sc = sc = nc;
412                                         clist_alloc_cblocks(&tp->t_outq,
413                                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
414                                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
415                                         sl_compress_init(&sc->sc_comp, -1);
416                                         goto slfound;
417                                 }
418                         }
419                         splx(s);
420                         return (ENXIO);
421                 }
422         slfound:
423                 sc->sc_flags |= SC_STATIC;
424                 break;
425
426         case SLIOCSKEEPAL:
427                 sc->sc_keepalive = *(u_int *)data * hz;
428                 if (sc->sc_keepalive) {
429                         sc->sc_flags |= SC_KEEPALIVE;
430                         sc->sc_kahandle = timeout(sl_keepalive, sc,
431                                                   sc->sc_keepalive);
432                 } else {
433                         if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
434                                 untimeout(sl_keepalive, sc, sc->sc_kahandle);
435                                 sc->sc_flags &= ~SC_KEEPALIVE;
436                         }
437                 }
438                 break;
439
440         case SLIOCGKEEPAL:
441                 *(int *)data = sc->sc_keepalive / hz;
442                 break;
443
444         case SLIOCSOUTFILL:
445                 sc->sc_outfill = *(u_int *)data * hz;
446                 if (sc->sc_outfill) {
447                         sc->sc_flags |= SC_OUTWAIT;
448                         sc->sc_ofhandle = timeout(sl_outfill, sc,
449                                                   sc->sc_outfill);
450                 } else {
451                         if ((sc->sc_flags & SC_OUTWAIT) != 0) {
452                                 untimeout(sl_outfill, sc, sc->sc_ofhandle);
453                                 sc->sc_flags &= ~SC_OUTWAIT;
454                         }
455                 }
456                 break;
457
458         case SLIOCGOUTFILL:
459                 *(int *)data = sc->sc_outfill / hz;
460                 break;
461
462         default:
463                 splx(s);
464                 return (ENOIOCTL);
465         }
466         splx(s);
467         return (0);
468 }
469
470 /*
471  * Queue a packet.  Start transmission if not active.
472  * Compression happens in slstart; if we do it here, IP TOS
473  * will cause us to not compress "background" packets, because
474  * ordering gets trashed.  It can be done for all packets in slstart.
475  */
476 static int
477 sloutput(ifp, m, dst, rtp)
478         struct ifnet *ifp;
479         register struct mbuf *m;
480         struct sockaddr *dst;
481         struct rtentry *rtp;
482 {
483         register struct sl_softc *sc = &sl_softc[ifp->if_unit];
484         register struct ip *ip;
485         register struct ifqueue *ifq;
486         int s;
487
488         /*
489          * `Cannot happen' (see slioctl).  Someday we will extend
490          * the line protocol to support other address families.
491          */
492         if (dst->sa_family != AF_INET) {
493                 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit,
494                         dst->sa_family);
495                 m_freem(m);
496                 sc->sc_if.if_noproto++;
497                 return (EAFNOSUPPORT);
498         }
499
500         if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
501                 m_freem(m);
502                 return (ENETDOWN);
503         }
504         if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
505                 m_freem(m);
506                 return (EHOSTUNREACH);
507         }
508         ifq = &sc->sc_if.if_snd;
509         ip = mtod(m, struct ip *);
510         if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
511                 m_freem(m);
512                 return (ENETRESET);             /* XXX ? */
513         }
514         if (ip->ip_tos & IPTOS_LOWDELAY)
515                 ifq = &sc->sc_fastq;
516         s = splimp();
517         if (IF_QFULL(ifq)) {
518                 IF_DROP(ifq);
519                 m_freem(m);
520                 splx(s);
521                 sc->sc_if.if_oerrors++;
522                 return (ENOBUFS);
523         }
524         IF_ENQUEUE(ifq, m);
525         if (sc->sc_ttyp->t_outq.c_cc == 0)
526                 slstart(sc->sc_ttyp);
527         splx(s);
528         return (0);
529 }
530
531 /*
532  * Start output on interface.  Get another datagram
533  * to send from the interface queue and map it to
534  * the interface before starting output.
535  */
536 static int
537 slstart(tp)
538         register struct tty *tp;
539 {
540         register struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
541         register struct mbuf *m;
542         register u_char *cp;
543         register struct ip *ip;
544         int s;
545         u_char bpfbuf[SLTMAX + SLIP_HDRLEN];
546         register int len = 0;
547
548         for (;;) {
549                 /*
550                  * Call output process whether or not there is more in the
551                  * output queue.  We are being called in lieu of ttstart
552                  * and must do what it would.
553                  */
554                 (*tp->t_oproc)(tp);
555
556                 if (tp->t_outq.c_cc != 0) {
557                         if (sc != NULL)
558                                 sc->sc_flags &= ~SC_OUTWAIT;
559                         if (tp->t_outq.c_cc > SLIP_HIWAT)
560                                 return 0;
561                 }
562
563                 /*
564                  * This happens briefly when the line shuts down.
565                  */
566                 if (sc == NULL)
567                         return 0;
568
569                 /*
570                  * Get a packet and send it to the interface.
571                  */
572                 s = splimp();
573                 IF_DEQUEUE(&sc->sc_fastq, m);
574                 if (m)
575                         sc->sc_if.if_omcasts++;         /* XXX */
576                 else
577                         IF_DEQUEUE(&sc->sc_if.if_snd, m);
578                 splx(s);
579                 if (m == NULL)
580                         return 0;
581
582                 /*
583                  * We do the header compression here rather than in sloutput
584                  * because the packets will be out of order if we are using TOS
585                  * queueing, and the connection id compression will get
586                  * munged when this happens.
587                  */
588                 if (sc->sc_if.if_bpf) {
589                         /*
590                          * We need to save the TCP/IP header before it's
591                          * compressed.  To avoid complicated code, we just
592                          * copy the entire packet into a stack buffer (since
593                          * this is a serial line, packets should be short
594                          * and/or the copy should be negligible cost compared
595                          * to the packet transmission time).
596                          */
597                         register struct mbuf *m1 = m;
598                         register u_char *cp = bpfbuf + SLIP_HDRLEN;
599
600                         len = 0;
601                         do {
602                                 register int mlen = m1->m_len;
603
604                                 bcopy(mtod(m1, caddr_t), cp, mlen);
605                                 cp += mlen;
606                                 len += mlen;
607                         } while ((m1 = m1->m_next) != NULL);
608                 }
609                 ip = mtod(m, struct ip *);
610                 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
611                         if (sc->sc_if.if_flags & SC_COMPRESS)
612                                 *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
613                                     &sc->sc_comp, 1);
614                 }
615                 if (sc->sc_if.if_bpf) {
616                         /*
617                          * Put the SLIP pseudo-"link header" in place.  The
618                          * compressed header is now at the beginning of the
619                          * mbuf.
620                          */
621                         bpfbuf[SLX_DIR] = SLIPDIR_OUT;
622                         bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN);
623                         bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN);
624                 }
625
626                 /*
627                  * If system is getting low on clists, just flush our
628                  * output queue (if the stuff was important, it'll get
629                  * retransmitted). Note that SLTMAX is used instead of
630                  * the current if_mtu setting because connections that
631                  * have already been established still use the original
632                  * (possibly larger) mss.
633                  */
634                 if (cfreecount < CLISTRESERVE + SLTMAX) {
635                         m_freem(m);
636                         sc->sc_if.if_collisions++;
637                         continue;
638                 }
639
640                 sc->sc_flags &= ~SC_OUTWAIT;
641                 /*
642                  * The extra FRAME_END will start up a new packet, and thus
643                  * will flush any accumulated garbage.  We do this whenever
644                  * the line may have been idle for some time.
645                  */
646                 if (tp->t_outq.c_cc == 0) {
647                         ++sc->sc_if.if_obytes;
648                         (void) putc(FRAME_END, &tp->t_outq);
649                 }
650
651                 while (m) {
652                         register u_char *ep;
653
654                         cp = mtod(m, u_char *); ep = cp + m->m_len;
655                         while (cp < ep) {
656                                 /*
657                                  * Find out how many bytes in the string we can
658                                  * handle without doing something special.
659                                  */
660                                 register u_char *bp = cp;
661
662                                 while (cp < ep) {
663                                         switch (*cp++) {
664                                         case FRAME_ESCAPE:
665                                         case FRAME_END:
666                                                 --cp;
667                                                 goto out;
668                                         }
669                                 }
670                                 out:
671                                 if (cp > bp) {
672                                         /*
673                                          * Put n characters at once
674                                          * into the tty output queue.
675                                          */
676                                         if (b_to_q((char *)bp, cp - bp,
677                                             &tp->t_outq))
678                                                 break;
679                                         sc->sc_if.if_obytes += cp - bp;
680                                 }
681                                 /*
682                                  * If there are characters left in the mbuf,
683                                  * the first one must be special..
684                                  * Put it out in a different form.
685                                  */
686                                 if (cp < ep) {
687                                         if (putc(FRAME_ESCAPE, &tp->t_outq))
688                                                 break;
689                                         if (putc(*cp++ == FRAME_ESCAPE ?
690                                            TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
691                                            &tp->t_outq)) {
692                                                 (void) unputc(&tp->t_outq);
693                                                 break;
694                                         }
695                                         sc->sc_if.if_obytes += 2;
696                                 }
697                         }
698                         m = m_free(m);
699                 }
700
701                 if (putc(FRAME_END, &tp->t_outq)) {
702                         /*
703                          * Not enough room.  Remove a char to make room
704                          * and end the packet normally.
705                          * If you get many collisions (more than one or two
706                          * a day) you probably do not have enough clists
707                          * and you should increase "nclist" in param.c.
708                          */
709                         (void) unputc(&tp->t_outq);
710                         (void) putc(FRAME_END, &tp->t_outq);
711                         sc->sc_if.if_collisions++;
712                 } else {
713                         ++sc->sc_if.if_obytes;
714                         sc->sc_if.if_opackets++;
715                 }
716         }
717         return 0;
718 }
719
720 /*
721  * Copy data buffer to mbuf chain; add ifnet pointer.
722  */
723 static struct mbuf *
724 sl_btom(sc, len)
725         register struct sl_softc *sc;
726         register int len;
727 {
728         register struct mbuf *m;
729
730         MGETHDR(m, M_DONTWAIT, MT_DATA);
731         if (m == NULL)
732                 return (NULL);
733
734         /*
735          * If we have more than MHLEN bytes, it's cheaper to
736          * queue the cluster we just filled & allocate a new one
737          * for the input buffer.  Otherwise, fill the mbuf we
738          * allocated above.  Note that code in the input routine
739          * guarantees that packet will fit in a cluster.
740          */
741         if (len >= MHLEN) {
742                 MCLGET(m, M_DONTWAIT);
743                 if ((m->m_flags & M_EXT) == 0) {
744                         /*
745                          * we couldn't get a cluster - if memory's this
746                          * low, it's time to start dropping packets.
747                          */
748                         (void) m_free(m);
749                         return (NULL);
750                 }
751                 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
752                 m->m_data = (caddr_t)sc->sc_buf;
753                 m->m_ext.ext_buf = (caddr_t)((intptr_t)sc->sc_buf &~ MCLOFSET);
754         } else
755                 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
756
757         m->m_len = len;
758         m->m_pkthdr.len = len;
759         m->m_pkthdr.rcvif = &sc->sc_if;
760         return (m);
761 }
762
763 /*
764  * tty interface receiver interrupt.
765  */
766 static int
767 slinput(c, tp)
768         register int c;
769         register struct tty *tp;
770 {
771         register struct sl_softc *sc;
772         register struct mbuf *m;
773         register int len;
774         int s;
775         u_char chdr[CHDR_LEN];
776
777         tk_nin++;
778         sc = (struct sl_softc *)tp->t_sc;
779         if (sc == NULL)
780                 return 0;
781         if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
782                 sc->sc_flags |= SC_ERROR;
783                 return 0;
784         }
785         c &= TTY_CHARMASK;
786
787         ++sc->sc_if.if_ibytes;
788
789         if (sc->sc_if.if_flags & IFF_DEBUG) {
790                 if (c == ABT_ESC) {
791                         /*
792                          * If we have a previous abort, see whether
793                          * this one is within the time limit.
794                          */
795                         if (sc->sc_abortcount &&
796                             time_second >= sc->sc_starttime + ABT_WINDOW)
797                                 sc->sc_abortcount = 0;
798                         /*
799                          * If we see an abort after "idle" time, count it;
800                          * record when the first abort escape arrived.
801                          */
802                         if (time_second >= sc->sc_lasttime + ABT_IDLE) {
803                                 if (++sc->sc_abortcount == 1)
804                                         sc->sc_starttime = time_second;
805                                 if (sc->sc_abortcount >= ABT_COUNT) {
806                                         slclose(tp,0);
807                                         return 0;
808                                 }
809                         }
810                 } else
811                         sc->sc_abortcount = 0;
812                 sc->sc_lasttime = time_second;
813         }
814
815         switch (c) {
816
817         case TRANS_FRAME_ESCAPE:
818                 if (sc->sc_escape)
819                         c = FRAME_ESCAPE;
820                 break;
821
822         case TRANS_FRAME_END:
823                 if (sc->sc_escape)
824                         c = FRAME_END;
825                 break;
826
827         case FRAME_ESCAPE:
828                 sc->sc_escape = 1;
829                 return 0;
830
831         case FRAME_END:
832                 sc->sc_flags &= ~SC_KEEPALIVE;
833                 if(sc->sc_flags & SC_ERROR) {
834                         sc->sc_flags &= ~SC_ERROR;
835                         goto newpack;
836                 }
837                 len = sc->sc_mp - sc->sc_buf;
838                 if (len < 3)
839                         /* less than min length packet - ignore */
840                         goto newpack;
841
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
854                 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
855                         if (c & 0x80)
856                                 c = TYPE_COMPRESSED_TCP;
857                         else if (c == TYPE_UNCOMPRESSED_TCP)
858                                 *sc->sc_buf &= 0x4f; /* XXX */
859                         /*
860                          * We've got something that's not an IP packet.
861                          * If compression is enabled, try to decompress it.
862                          * Otherwise, if `auto-enable' compression is on and
863                          * it's a reasonable packet, decompress it and then
864                          * enable compression.  Otherwise, drop it.
865                          */
866                         if (sc->sc_if.if_flags & SC_COMPRESS) {
867                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
868                                                         (u_int)c, &sc->sc_comp);
869                                 if (len <= 0)
870                                         goto error;
871                         } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) &&
872                             c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
873                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
874                                                         (u_int)c, &sc->sc_comp);
875                                 if (len <= 0)
876                                         goto error;
877                                 sc->sc_if.if_flags |= SC_COMPRESS;
878                         } else
879                                 goto error;
880                 }
881                 if (sc->sc_if.if_bpf) {
882                         /*
883                          * Put the SLIP pseudo-"link header" in place.
884                          * We couldn't do this any earlier since
885                          * decompression probably moved the buffer
886                          * pointer.  Then, invoke BPF.
887                          */
888                         register u_char *hp = sc->sc_buf - SLIP_HDRLEN;
889
890                         hp[SLX_DIR] = SLIPDIR_IN;
891                         bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
892                         bpf_tap(&sc->sc_if, hp, len + SLIP_HDRLEN);
893                 }
894                 m = sl_btom(sc, len);
895                 if (m == NULL)
896                         goto error;
897
898                 sc->sc_if.if_ipackets++;
899
900                 if ((sc->sc_if.if_flags & IFF_UP) == 0) {
901                         m_freem(m);
902                         goto newpack;
903                 }
904
905                 s = splimp();
906                 if (IF_QFULL(&ipintrq)) {
907                         IF_DROP(&ipintrq);
908                         sc->sc_if.if_ierrors++;
909                         sc->sc_if.if_iqdrops++;
910                         m_freem(m);
911                 } else {
912                         IF_ENQUEUE(&ipintrq, m);
913                         schednetisr(NETISR_IP);
914                 }
915                 splx(s);
916                 goto newpack;
917         }
918         if (sc->sc_mp < sc->sc_ep) {
919                 *sc->sc_mp++ = c;
920                 sc->sc_escape = 0;
921                 return 0;
922         }
923
924         /* can't put lower; would miss an extra frame */
925         sc->sc_flags |= SC_ERROR;
926
927 error:
928         sc->sc_if.if_ierrors++;
929 newpack:
930         sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX;
931         sc->sc_escape = 0;
932         return 0;
933 }
934
935 /*
936  * Process an ioctl request.
937  */
938 static int
939 slioctl(ifp, cmd, data)
940         register struct ifnet *ifp;
941         u_long cmd;
942         caddr_t data;
943 {
944         register struct ifaddr *ifa = (struct ifaddr *)data;
945         register struct ifreq *ifr = (struct ifreq *)data;
946         register int s, error = 0;
947
948         s = splimp();
949
950         switch (cmd) {
951
952         case SIOCSIFFLAGS:
953                 /*
954                  * if.c will set the interface up even if we
955                  * don't want it to.
956                  */
957                 if (sl_softc[ifp->if_unit].sc_ttyp == NULL) {
958                         ifp->if_flags &= ~IFF_UP;
959                 }
960                 break;
961         case SIOCSIFADDR:
962                 /*
963                  * This is "historical" - set the interface up when
964                  * setting the address.
965                  */
966                 if (ifa->ifa_addr->sa_family == AF_INET) {
967                         if (sl_softc[ifp->if_unit].sc_ttyp != NULL)
968                                 ifp->if_flags |= IFF_UP;
969                 } else {
970                         error = EAFNOSUPPORT;
971                 }
972                 break;
973
974         case SIOCSIFDSTADDR:
975                 if (ifa->ifa_addr->sa_family != AF_INET)
976                         error = EAFNOSUPPORT;
977                 break;
978
979         case SIOCADDMULTI:
980         case SIOCDELMULTI:
981                 break;
982
983         case SIOCSIFMTU:
984                 /*
985                  * Set the interface MTU.
986                  */
987                 if (ifr->ifr_mtu > SLTMAX)
988                         error = EINVAL;
989                 else {
990                         struct tty *tp;
991
992                         ifp->if_mtu = ifr->ifr_mtu;
993                         tp = sl_softc[ifp->if_unit].sc_ttyp;
994                         if (tp != NULL)
995                                 clist_alloc_cblocks(&tp->t_outq,
996                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1,
997                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1);
998                 }
999                 break;
1000
1001         default:
1002                 error = EINVAL;
1003         }
1004         splx(s);
1005         return (error);
1006 }
1007
1008 static void
1009 sl_keepalive(chan)
1010         void *chan;
1011 {
1012         struct sl_softc *sc = chan;
1013
1014         if (sc->sc_keepalive) {
1015                 if (sc->sc_flags & SC_KEEPALIVE)
1016                         pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1);
1017                 else
1018                         sc->sc_flags |= SC_KEEPALIVE;
1019                 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
1020         } else {
1021                 sc->sc_flags &= ~SC_KEEPALIVE;
1022         }
1023 }
1024
1025 static void
1026 sl_outfill(chan)
1027         void *chan;
1028 {
1029         struct sl_softc *sc = chan;
1030         register struct tty *tp = sc->sc_ttyp;
1031         int s;
1032
1033         if (sc->sc_outfill && tp != NULL) {
1034                 if (sc->sc_flags & SC_OUTWAIT) {
1035                         s = splimp ();
1036                         ++sc->sc_if.if_obytes;
1037                         (void) putc(FRAME_END, &tp->t_outq);
1038                         (*tp->t_oproc)(tp);
1039                         splx (s);
1040                 } else
1041                         sc->sc_flags |= SC_OUTWAIT;
1042                 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
1043         } else {
1044                 sc->sc_flags &= ~SC_OUTWAIT;
1045         }
1046 }