Get rid of mb_map. Retool the mbuf and mbuf cluster allocator to use
[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 1.14 2004/07/31 07:52:54 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 "use_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 "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 (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 (struct sl_softc *);
184 static struct mbuf *sl_btom (struct sl_softc *, int);
185 static timeout_t sl_keepalive;
186 static timeout_t sl_outfill;
187 static int      slclose (struct tty *,int);
188 static int      slinput (int, struct tty *);
189 static int      slioctl (struct ifnet *, u_long, caddr_t, struct ucred *);
190 static int      sltioctl (struct tty *, u_long, caddr_t, int, struct thread *);
191 static int      slopen (dev_t, struct tty *);
192 static int      sloutput (struct ifnet *,
193             struct mbuf *, struct sockaddr *, struct rtentry *);
194 static int      slstart (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         struct sl_softc *sc;
210         int i = 0;
211
212         linesw[SLIPDISC] = slipdisc;
213
214         for (sc = sl_softc; i < NSL; sc++) {
215                 if_initname(&(sc->sc_if), "sl", i++);
216                 sc->sc_if.if_mtu = SLMTU;
217                 sc->sc_if.if_flags =
218 #ifdef SLIP_IFF_OPTS
219                     SLIP_IFF_OPTS;
220 #else
221                     IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
222 #endif
223                 sc->sc_if.if_type = IFT_SLIP;
224                 sc->sc_if.if_ioctl = slioctl;
225                 sc->sc_if.if_output = sloutput;
226                 sc->sc_if.if_snd.ifq_maxlen = 50;
227                 sc->sc_fastq.ifq_maxlen = 32;
228                 sc->sc_if.if_linkmib = sc;
229                 sc->sc_if.if_linkmiblen = sizeof *sc;
230                 if_attach(&sc->sc_if);
231                 bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
232         }
233 }
234
235 static int
236 slinit(sc)
237         struct sl_softc *sc;
238 {
239 #ifdef __i386__
240         int s;
241
242         s = splhigh();
243         tty_imask |= net_imask;
244         net_imask = tty_imask;
245         update_intr_masks();
246         splx(s);
247         if (bootverbose)
248                 printf("new imasks: bio %x, tty %x, net %x\n",
249                     bio_imask, tty_imask, net_imask);
250 #endif
251         if (sc->sc_ep == NULL)
252                 sc->sc_ep = malloc(SLBUFSIZE, M_DEVBUF, M_WAITOK);
253         sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX;
254         sc->sc_mp = sc->sc_buf;
255         sl_compress_init(&sc->sc_comp, -1);
256         return (1);
257 }
258
259 /*
260  * Line specific open routine.
261  * Attach the given tty to the first available sl unit.
262  */
263 /* ARGSUSED */
264 static int
265 slopen(dev_t dev, struct tty *tp)
266 {
267         struct sl_softc *sc;
268         int nsl;
269         int s, error;
270         struct thread *td = curthread;  /* XXX */
271
272         error = suser(td);
273         if (error)
274                 return (error);
275
276         if (tp->t_line == SLIPDISC)
277                 return (0);
278
279         for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++)
280                 if (sc->sc_ttyp == NULL && !(sc->sc_flags & SC_STATIC)) {
281                         if (slinit(sc) == 0)
282                                 return (ENOBUFS);
283                         tp->t_sc = (caddr_t)sc;
284                         sc->sc_ttyp = tp;
285                         sc->sc_if.if_baudrate = tp->t_ospeed;
286                         ttyflush(tp, FREAD | FWRITE);
287
288                         tp->t_line = SLIPDISC;
289                         /*
290                          * We don't use t_canq or t_rawq, so reduce their
291                          * cblock resources to 0.  Reserve enough cblocks
292                          * for t_outq to guarantee that we can fit a full
293                          * packet if the SLIP_HIWAT check allows slstart()
294                          * to loop.  Use the same value for the cblock
295                          * limit since the reserved blocks should always
296                          * be enough.  Reserving cblocks probably makes
297                          * the CLISTRESERVE check unnecessary and wasteful.
298                          */
299                         clist_alloc_cblocks(&tp->t_canq, 0, 0);
300                         clist_alloc_cblocks(&tp->t_outq,
301                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
302                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
303                         clist_alloc_cblocks(&tp->t_rawq, 0, 0);
304
305                         s = splnet();
306                         if_up(&sc->sc_if);
307                         splx(s);
308                         return (0);
309                 }
310         return (ENXIO);
311 }
312
313 /*
314  * Line specific close routine.
315  * Detach the tty from the sl unit.
316  */
317 static int
318 slclose(tp,flag)
319         struct tty *tp;
320         int flag;
321 {
322         struct sl_softc *sc;
323         int s;
324
325         ttyflush(tp, FREAD | FWRITE);
326         /*
327          * XXX the placement of the following spl is misleading.  tty
328          * interrupts must be blocked across line discipline switches
329          * and throughout closes to avoid races.
330          */
331         s = splimp();           /* actually, max(spltty, splnet) */
332         clist_free_cblocks(&tp->t_outq);
333         tp->t_line = 0;
334         sc = (struct sl_softc *)tp->t_sc;
335         if (sc != NULL) {
336                 if (sc->sc_outfill) {
337                         sc->sc_outfill = 0;
338                         untimeout(sl_outfill, sc, sc->sc_ofhandle);
339                 }
340                 if (sc->sc_keepalive) {
341                         sc->sc_keepalive = 0;
342                         untimeout(sl_keepalive, sc, sc->sc_kahandle);
343                 }
344                 if_down(&sc->sc_if);
345                 sc->sc_flags &= SC_STATIC;
346                 sc->sc_ttyp = NULL;
347                 tp->t_sc = NULL;
348                 if (sc->sc_ep) {
349                         free(sc->sc_ep, M_DEVBUF);
350                         sc->sc_ep = NULL;
351                 }
352                 sc->sc_mp = 0;
353                 sc->sc_buf = 0;
354         }
355         splx(s);
356         return 0;
357 }
358
359 /*
360  * Line specific (tty) ioctl routine.
361  * Provide a way to get the sl unit number.
362  */
363 /* ARGSUSED */
364 static int
365 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct thread *p)
366 {
367         struct sl_softc *sc = (struct sl_softc *)tp->t_sc, *nc, *tmpnc;
368         int s, nsl;
369
370         s = splimp();
371         switch (cmd) {
372         case SLIOCGUNIT:
373                 *(int *)data = sc->sc_if.if_dunit;
374                 break;
375
376         case SLIOCSUNIT:
377                 if (sc->sc_if.if_dunit != *(u_int *)data) {
378                         for (nsl = NSL, nc = sl_softc; --nsl >= 0; nc++) {
379                                 if (   nc->sc_if.if_dunit == *(u_int *)data
380                                     && nc->sc_ttyp == NULL
381                                    ) {
382                                         tmpnc = malloc(sizeof *tmpnc, M_TEMP,
383                                                        M_WAITOK);
384                                         *tmpnc = *nc;
385                                         *nc = *sc;
386                                         nc->sc_if = tmpnc->sc_if;
387                                         tmpnc->sc_if = sc->sc_if;
388                                         *sc = *tmpnc;
389                                         free(tmpnc, M_TEMP);
390                                         if (sc->sc_if.if_flags & IFF_UP) {
391                                                 if_down(&sc->sc_if);
392                                                 if (!(nc->sc_if.if_flags & IFF_UP))
393                                                         if_up(&nc->sc_if);
394                                         } else if (nc->sc_if.if_flags & IFF_UP)
395                                                 if_down(&nc->sc_if);
396                                         sc->sc_flags &= ~SC_STATIC;
397                                         sc->sc_flags |= (nc->sc_flags & SC_STATIC);
398                                         tp->t_sc = sc = nc;
399                                         clist_alloc_cblocks(&tp->t_outq,
400                                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1,
401                                             SLIP_HIWAT + 2 * sc->sc_if.if_mtu + 1);
402                                         sl_compress_init(&sc->sc_comp, -1);
403                                         goto slfound;
404                                 }
405                         }
406                         splx(s);
407                         return (ENXIO);
408                 }
409         slfound:
410                 sc->sc_flags |= SC_STATIC;
411                 break;
412
413         case SLIOCSKEEPAL:
414                 sc->sc_keepalive = *(u_int *)data * hz;
415                 if (sc->sc_keepalive) {
416                         sc->sc_flags |= SC_KEEPALIVE;
417                         sc->sc_kahandle = timeout(sl_keepalive, sc,
418                                                   sc->sc_keepalive);
419                 } else {
420                         if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
421                                 untimeout(sl_keepalive, sc, sc->sc_kahandle);
422                                 sc->sc_flags &= ~SC_KEEPALIVE;
423                         }
424                 }
425                 break;
426
427         case SLIOCGKEEPAL:
428                 *(int *)data = sc->sc_keepalive / hz;
429                 break;
430
431         case SLIOCSOUTFILL:
432                 sc->sc_outfill = *(u_int *)data * hz;
433                 if (sc->sc_outfill) {
434                         sc->sc_flags |= SC_OUTWAIT;
435                         sc->sc_ofhandle = timeout(sl_outfill, sc,
436                                                   sc->sc_outfill);
437                 } else {
438                         if ((sc->sc_flags & SC_OUTWAIT) != 0) {
439                                 untimeout(sl_outfill, sc, sc->sc_ofhandle);
440                                 sc->sc_flags &= ~SC_OUTWAIT;
441                         }
442                 }
443                 break;
444
445         case SLIOCGOUTFILL:
446                 *(int *)data = sc->sc_outfill / hz;
447                 break;
448
449         default:
450                 splx(s);
451                 return (ENOIOCTL);
452         }
453         splx(s);
454         return (0);
455 }
456
457 /*
458  * Queue a packet.  Start transmission if not active.
459  * Compression happens in slstart; if we do it here, IP TOS
460  * will cause us to not compress "background" packets, because
461  * ordering gets trashed.  It can be done for all packets in slstart.
462  */
463 static int
464 sloutput(ifp, m, dst, rtp)
465         struct ifnet *ifp;
466         struct mbuf *m;
467         struct sockaddr *dst;
468         struct rtentry *rtp;
469 {
470         struct sl_softc *sc = &sl_softc[ifp->if_dunit];
471         struct ip *ip;
472         struct ifqueue *ifq;
473         int s;
474
475         /*
476          * `Cannot happen' (see slioctl).  Someday we will extend
477          * the line protocol to support other address families.
478          */
479         if (dst->sa_family != AF_INET) {
480                 printf("%s: af%d not supported\n", sc->sc_if.if_xname,
481                         dst->sa_family);
482                 m_freem(m);
483                 sc->sc_if.if_noproto++;
484                 return (EAFNOSUPPORT);
485         }
486
487         if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
488                 m_freem(m);
489                 return (ENETDOWN);
490         }
491         if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
492                 m_freem(m);
493                 return (EHOSTUNREACH);
494         }
495         ifq = &sc->sc_if.if_snd;
496         ip = mtod(m, struct ip *);
497         if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
498                 m_freem(m);
499                 return (ENETRESET);             /* XXX ? */
500         }
501         if (ip->ip_tos & IPTOS_LOWDELAY)
502                 ifq = &sc->sc_fastq;
503         s = splimp();
504         if (IF_QFULL(ifq)) {
505                 IF_DROP(ifq);
506                 m_freem(m);
507                 splx(s);
508                 sc->sc_if.if_oerrors++;
509                 return (ENOBUFS);
510         }
511         IF_ENQUEUE(ifq, m);
512         if (sc->sc_ttyp->t_outq.c_cc == 0)
513                 slstart(sc->sc_ttyp);
514         splx(s);
515         return (0);
516 }
517
518 /*
519  * Start output on interface.  Get another datagram
520  * to send from the interface queue and map it to
521  * the interface before starting output.
522  */
523 static int
524 slstart(tp)
525         struct tty *tp;
526 {
527         struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
528         struct mbuf *m;
529         u_char *cp;
530         struct ip *ip;
531         int s;
532         u_char bpfbuf[SLTMAX + SLIP_HDRLEN];
533         int len = 0;
534
535         for (;;) {
536                 /*
537                  * Call output process whether or not there is more in the
538                  * output queue.  We are being called in lieu of ttstart
539                  * and must do what it would.
540                  */
541                 (*tp->t_oproc)(tp);
542
543                 if (tp->t_outq.c_cc != 0) {
544                         if (sc != NULL)
545                                 sc->sc_flags &= ~SC_OUTWAIT;
546                         if (tp->t_outq.c_cc > SLIP_HIWAT)
547                                 return 0;
548                 }
549
550                 /*
551                  * This happens briefly when the line shuts down.
552                  */
553                 if (sc == NULL)
554                         return 0;
555
556                 /*
557                  * Get a packet and send it to the interface.
558                  */
559                 s = splimp();
560                 IF_DEQUEUE(&sc->sc_fastq, m);
561                 if (m)
562                         sc->sc_if.if_omcasts++;         /* XXX */
563                 else
564                         IF_DEQUEUE(&sc->sc_if.if_snd, m);
565                 splx(s);
566                 if (m == NULL)
567                         return 0;
568
569                 /*
570                  * We do the header compression here rather than in sloutput
571                  * because the packets will be out of order if we are using TOS
572                  * queueing, and the connection id compression will get
573                  * munged when this happens.
574                  */
575                 if (sc->sc_if.if_bpf) {
576                         /*
577                          * We need to save the TCP/IP header before it's
578                          * compressed.  To avoid complicated code, we just
579                          * copy the entire packet into a stack buffer (since
580                          * this is a serial line, packets should be short
581                          * and/or the copy should be negligible cost compared
582                          * to the packet transmission time).
583                          */
584                         struct mbuf *m1 = m;
585                         u_char *cp = bpfbuf + SLIP_HDRLEN;
586
587                         len = 0;
588                         do {
589                                 int mlen = m1->m_len;
590
591                                 bcopy(mtod(m1, caddr_t), cp, mlen);
592                                 cp += mlen;
593                                 len += mlen;
594                         } while ((m1 = m1->m_next) != NULL);
595                 }
596                 ip = mtod(m, struct ip *);
597                 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
598                         if (sc->sc_if.if_flags & SC_COMPRESS)
599                                 *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
600                                     &sc->sc_comp, 1);
601                 }
602                 if (sc->sc_if.if_bpf) {
603                         /*
604                          * Put the SLIP pseudo-"link header" in place.  The
605                          * compressed header is now at the beginning of the
606                          * mbuf.
607                          */
608                         bpfbuf[SLX_DIR] = SLIPDIR_OUT;
609                         bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN);
610                         bpf_tap(&sc->sc_if, bpfbuf, len + SLIP_HDRLEN);
611                 }
612
613                 /*
614                  * If system is getting low on clists, just flush our
615                  * output queue (if the stuff was important, it'll get
616                  * retransmitted). Note that SLTMAX is used instead of
617                  * the current if_mtu setting because connections that
618                  * have already been established still use the original
619                  * (possibly larger) mss.
620                  */
621                 if (cfreecount < CLISTRESERVE + SLTMAX) {
622                         m_freem(m);
623                         sc->sc_if.if_collisions++;
624                         continue;
625                 }
626
627                 sc->sc_flags &= ~SC_OUTWAIT;
628                 /*
629                  * The extra FRAME_END will start up a new packet, and thus
630                  * will flush any accumulated garbage.  We do this whenever
631                  * the line may have been idle for some time.
632                  */
633                 if (tp->t_outq.c_cc == 0) {
634                         ++sc->sc_if.if_obytes;
635                         (void) putc(FRAME_END, &tp->t_outq);
636                 }
637
638                 while (m) {
639                         u_char *ep;
640
641                         cp = mtod(m, u_char *); ep = cp + m->m_len;
642                         while (cp < ep) {
643                                 /*
644                                  * Find out how many bytes in the string we can
645                                  * handle without doing something special.
646                                  */
647                                 u_char *bp = cp;
648
649                                 while (cp < ep) {
650                                         switch (*cp++) {
651                                         case FRAME_ESCAPE:
652                                         case FRAME_END:
653                                                 --cp;
654                                                 goto out;
655                                         }
656                                 }
657                                 out:
658                                 if (cp > bp) {
659                                         /*
660                                          * Put n characters at once
661                                          * into the tty output queue.
662                                          */
663                                         if (b_to_q((char *)bp, cp - bp,
664                                             &tp->t_outq))
665                                                 break;
666                                         sc->sc_if.if_obytes += cp - bp;
667                                 }
668                                 /*
669                                  * If there are characters left in the mbuf,
670                                  * the first one must be special..
671                                  * Put it out in a different form.
672                                  */
673                                 if (cp < ep) {
674                                         if (putc(FRAME_ESCAPE, &tp->t_outq))
675                                                 break;
676                                         if (putc(*cp++ == FRAME_ESCAPE ?
677                                            TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
678                                            &tp->t_outq)) {
679                                                 (void) unputc(&tp->t_outq);
680                                                 break;
681                                         }
682                                         sc->sc_if.if_obytes += 2;
683                                 }
684                         }
685                         m = m_free(m);
686                 }
687
688                 if (putc(FRAME_END, &tp->t_outq)) {
689                         /*
690                          * Not enough room.  Remove a char to make room
691                          * and end the packet normally.
692                          * If you get many collisions (more than one or two
693                          * a day) you probably do not have enough clists
694                          * and you should increase "nclist" in param.c.
695                          */
696                         (void) unputc(&tp->t_outq);
697                         (void) putc(FRAME_END, &tp->t_outq);
698                         sc->sc_if.if_collisions++;
699                 } else {
700                         ++sc->sc_if.if_obytes;
701                         sc->sc_if.if_opackets++;
702                 }
703         }
704         return 0;
705 }
706
707 /*
708  * Copy data buffer to mbuf chain; add ifnet pointer.
709  */
710 static struct mbuf *
711 sl_btom(sc, len)
712         struct sl_softc *sc;
713         int len;
714 {
715         struct mbuf *m;
716
717         if (len >= MCLBYTES)
718                 return (NULL);
719
720         MGETHDR(m, MB_DONTWAIT, MT_DATA);
721         if (m == NULL)
722                 return (NULL);
723
724         /*
725          * If we have more than MHLEN bytes, it's cheaper to
726          * queue the cluster we just filled & allocate a new one
727          * for the input buffer.  Otherwise, fill the mbuf we
728          * allocated above.  Note that code in the input routine
729          * guarantees that packet will fit in a cluster.
730          */
731         if (len >= MHLEN) {
732                 MCLGET(m, MB_DONTWAIT);
733                 if ((m->m_flags & M_EXT) == 0) {
734                         /*
735                          * we couldn't get a cluster - if memory's this
736                          * low, it's time to start dropping packets.
737                          */
738                         m_free(m);
739                         return (NULL);
740                 }
741         }
742         bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
743         m->m_len = len;
744         m->m_pkthdr.len = len;
745         m->m_pkthdr.rcvif = &sc->sc_if;
746         return (m);
747 }
748
749 /*
750  * tty interface receiver interrupt.
751  */
752 static int
753 slinput(c, tp)
754         int c;
755         struct tty *tp;
756 {
757         struct sl_softc *sc;
758         struct mbuf *m;
759         int len;
760         u_char chdr[CHDR_LEN];
761
762         tk_nin++;
763         sc = (struct sl_softc *)tp->t_sc;
764         if (sc == NULL)
765                 return 0;
766         if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
767                 sc->sc_flags |= SC_ERROR;
768                 return 0;
769         }
770         c &= TTY_CHARMASK;
771
772         ++sc->sc_if.if_ibytes;
773
774         if (sc->sc_if.if_flags & IFF_DEBUG) {
775                 if (c == ABT_ESC) {
776                         /*
777                          * If we have a previous abort, see whether
778                          * this one is within the time limit.
779                          */
780                         if (sc->sc_abortcount &&
781                             time_second >= sc->sc_starttime + ABT_WINDOW)
782                                 sc->sc_abortcount = 0;
783                         /*
784                          * If we see an abort after "idle" time, count it;
785                          * record when the first abort escape arrived.
786                          */
787                         if (time_second >= sc->sc_lasttime + ABT_IDLE) {
788                                 if (++sc->sc_abortcount == 1)
789                                         sc->sc_starttime = time_second;
790                                 if (sc->sc_abortcount >= ABT_COUNT) {
791                                         slclose(tp,0);
792                                         return 0;
793                                 }
794                         }
795                 } else
796                         sc->sc_abortcount = 0;
797                 sc->sc_lasttime = time_second;
798         }
799
800         switch (c) {
801
802         case TRANS_FRAME_ESCAPE:
803                 if (sc->sc_escape)
804                         c = FRAME_ESCAPE;
805                 break;
806
807         case TRANS_FRAME_END:
808                 if (sc->sc_escape)
809                         c = FRAME_END;
810                 break;
811
812         case FRAME_ESCAPE:
813                 sc->sc_escape = 1;
814                 return 0;
815
816         case FRAME_END:
817                 sc->sc_flags &= ~SC_KEEPALIVE;
818                 if(sc->sc_flags & SC_ERROR) {
819                         sc->sc_flags &= ~SC_ERROR;
820                         goto newpack;
821                 }
822                 len = sc->sc_mp - sc->sc_buf;
823                 if (len < 3)
824                         /* less than min length packet - ignore */
825                         goto newpack;
826
827                 if (sc->sc_if.if_bpf) {
828                         /*
829                          * Save the compressed header, so we
830                          * can tack it on later.  Note that we
831                          * will end up copying garbage in some
832                          * cases but this is okay.  We remember
833                          * where the buffer started so we can
834                          * compute the new header length.
835                          */
836                         bcopy(sc->sc_buf, chdr, CHDR_LEN);
837                 }
838
839                 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
840                         if (c & 0x80)
841                                 c = TYPE_COMPRESSED_TCP;
842                         else if (c == TYPE_UNCOMPRESSED_TCP)
843                                 *sc->sc_buf &= 0x4f; /* XXX */
844                         /*
845                          * We've got something that's not an IP packet.
846                          * If compression is enabled, try to decompress it.
847                          * Otherwise, if `auto-enable' compression is on and
848                          * it's a reasonable packet, decompress it and then
849                          * enable compression.  Otherwise, drop it.
850                          */
851                         if (sc->sc_if.if_flags & SC_COMPRESS) {
852                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
853                                                         (u_int)c, &sc->sc_comp);
854                                 if (len <= 0)
855                                         goto error;
856                         } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) &&
857                             c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
858                                 len = sl_uncompress_tcp(&sc->sc_buf, len,
859                                                         (u_int)c, &sc->sc_comp);
860                                 if (len <= 0)
861                                         goto error;
862                                 sc->sc_if.if_flags |= SC_COMPRESS;
863                         } else
864                                 goto error;
865                 }
866                 if (sc->sc_if.if_bpf) {
867                         /*
868                          * Put the SLIP pseudo-"link header" in place.
869                          * We couldn't do this any earlier since
870                          * decompression probably moved the buffer
871                          * pointer.  Then, invoke BPF.
872                          */
873                         u_char *hp = sc->sc_buf - SLIP_HDRLEN;
874
875                         hp[SLX_DIR] = SLIPDIR_IN;
876                         bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
877                         bpf_tap(&sc->sc_if, hp, len + SLIP_HDRLEN);
878                 }
879                 m = sl_btom(sc, len);
880                 if (m == NULL)
881                         goto error;
882
883                 sc->sc_if.if_ipackets++;
884
885                 if ((sc->sc_if.if_flags & IFF_UP) == 0) {
886                         m_freem(m);
887                         goto newpack;
888                 }
889
890                 if (netisr_queue(NETISR_IP, m)) {
891                         sc->sc_if.if_ierrors++;
892                         sc->sc_if.if_iqdrops++;
893                 }
894
895                 goto newpack;
896         }
897         if (sc->sc_mp < sc->sc_ep + SLBUFSIZE) {
898                 *sc->sc_mp++ = c;
899                 sc->sc_escape = 0;
900                 return 0;
901         }
902
903         /* can't put lower; would miss an extra frame */
904         sc->sc_flags |= SC_ERROR;
905
906 error:
907         sc->sc_if.if_ierrors++;
908 newpack:
909         sc->sc_mp = sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX;
910         sc->sc_escape = 0;
911         return 0;
912 }
913
914 /*
915  * Process an ioctl request.
916  */
917 static int
918 slioctl(ifp, cmd, data, cr)
919         struct ifnet *ifp;
920         u_long cmd;
921         caddr_t data;
922         struct ucred *cr;
923 {
924         struct ifaddr *ifa = (struct ifaddr *)data;
925         struct ifreq *ifr = (struct ifreq *)data;
926         int s, error = 0;
927
928         s = splimp();
929
930         switch (cmd) {
931
932         case SIOCSIFFLAGS:
933                 /*
934                  * if.c will set the interface up even if we
935                  * don't want it to.
936                  */
937                 if (sl_softc[ifp->if_dunit].sc_ttyp == NULL) {
938                         ifp->if_flags &= ~IFF_UP;
939                 }
940                 break;
941         case SIOCSIFADDR:
942                 /*
943                  * This is "historical" - set the interface up when
944                  * setting the address.
945                  */
946                 if (ifa->ifa_addr->sa_family == AF_INET) {
947                         if (sl_softc[ifp->if_dunit].sc_ttyp != NULL)
948                                 ifp->if_flags |= IFF_UP;
949                 } else {
950                         error = EAFNOSUPPORT;
951                 }
952                 break;
953
954         case SIOCSIFDSTADDR:
955                 if (ifa->ifa_addr->sa_family != AF_INET)
956                         error = EAFNOSUPPORT;
957                 break;
958
959         case SIOCADDMULTI:
960         case SIOCDELMULTI:
961                 break;
962
963         case SIOCSIFMTU:
964                 /*
965                  * Set the interface MTU.
966                  */
967                 if (ifr->ifr_mtu > SLTMAX)
968                         error = EINVAL;
969                 else {
970                         struct tty *tp;
971
972                         ifp->if_mtu = ifr->ifr_mtu;
973                         tp = sl_softc[ifp->if_dunit].sc_ttyp;
974                         if (tp != NULL)
975                                 clist_alloc_cblocks(&tp->t_outq,
976                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1,
977                                     SLIP_HIWAT + 2 * ifp->if_mtu + 1);
978                 }
979                 break;
980
981         default:
982                 error = EINVAL;
983         }
984         splx(s);
985         return (error);
986 }
987
988 static void
989 sl_keepalive(chan)
990         void *chan;
991 {
992         struct sl_softc *sc = chan;
993
994         if (sc->sc_keepalive) {
995                 if (sc->sc_flags & SC_KEEPALIVE)
996                         pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1);
997                 else
998                         sc->sc_flags |= SC_KEEPALIVE;
999                 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
1000         } else {
1001                 sc->sc_flags &= ~SC_KEEPALIVE;
1002         }
1003 }
1004
1005 static void
1006 sl_outfill(chan)
1007         void *chan;
1008 {
1009         struct sl_softc *sc = chan;
1010         struct tty *tp = sc->sc_ttyp;
1011         int s;
1012
1013         if (sc->sc_outfill && tp != NULL) {
1014                 if (sc->sc_flags & SC_OUTWAIT) {
1015                         s = splimp ();
1016                         ++sc->sc_if.if_obytes;
1017                         (void) putc(FRAME_END, &tp->t_outq);
1018                         (*tp->t_oproc)(tp);
1019                         splx (s);
1020                 } else
1021                         sc->sc_flags |= SC_OUTWAIT;
1022                 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
1023         } else {
1024                 sc->sc_flags &= ~SC_OUTWAIT;
1025         }
1026 }