1 /*
2 * Copyright (c) 1987, 1989 Regents of the University of California.
3 * 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 * $Id: $
34 */
35
36 /*
37 * Serial Line interface
38 *
39 * Rick Adams
40 * Center for Seismic Studies
41 * 1300 N 17th Street, Suite 1450
42 * Arlington, Virginia 22209
43 * (703)276-7900
44 * rick@seismo.ARPA
45 * seismo!rick
46 *
47 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris).
48 * N.B.: this belongs in netinet, not net, the way it stands now.
49 * Should have a link-layer type designation, but wouldn't be
50 * backwards-compatible.
51 *
52 * Converted to 4.3BSD Beta by Chris Torek.
53 * Other changes made at Berkeley, based in part on code by Kirk Smith.
54 * W. Jolitz added slip abort.
55 *
56 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov).
57 * Added priority queuing for "interactive" traffic; hooks for TCP
58 * header compression; ICMP filtering (at 2400 baud, some cretin
59 * pinging you can use up all your bandwidth). Made low clist behavior
60 * more robust and slightly less likely to hang serial line.
61 * Sped up a bunch of things.
62 *
63 * Note that splimp() is used throughout to block both (tty) input
64 * interrupts and network activity; thus, splimp must be >= spltty.
65 */
66
67 static char *sl_config =
68 "slip 4. # serial line IP (sl0)";
69
70 #include "sys/param.h"
71 /*#include "sys/ucred.h"*/
72 #include "sys/socket.h"
73 #include "sys/file.h"
74 #include "sys/ioctl.h"
75 #include "privilege.h"
76 #include "sys/errno.h"
77 #include "proc.h"
78 #include "mbuf.h"
79 #include "dkstat.h"
80 #include "tty.h"
81 #include "kernel.h"
82 #include "modconfig.h"
83
84 #include "machine/cpu.h"
85
86 #include "if.h"
87 #include "if_types.h"
88 #include "netisr.h"
89 #include "route.h"
90 #if INET
91 #include "in.h"
92 #include "in_systm.h"
93 #include "in_var.h"
94 #include "ip.h"
95 #else
96 Huh? Slip without inet?
97 #endif
98
99 #include "slcompress.h"
100 #include "if_slvar.h"
101
102 #include "prototypes.h"
103
104 /*
105 * SLMAX is a hard limit on input packet size. To simplify the code
106 * and improve performance, we require that packets fit in an mbuf
107 * cluster, and if we get a compressed packet, there's enough extra
108 * room to expand the header into a max length tcp/ip header (128
109 * bytes). So, SLMAX can be at most
110 * MCLBYTES - 128
111 *
112 * SLMTU is a hard limit on output packet size. To insure good
113 * interactive response, SLMTU wants to be the smallest size that
114 * amortizes the header cost. (Remember that even with
115 * type-of-service queuing, we have to wait for any in-progress
116 * packet to finish. I.e., we wait, on the average, 1/2 * mtu /
117 * cps, where cps is the line speed in characters per second.
118 * E.g., 533ms wait for a 1024 byte MTU on a 9600 baud line. The
119 * average compressed header size is 6-8 bytes so any MTU > 90
120 * bytes will give us 90% of the line bandwidth. A 100ms wait is
121 * tolerable (500ms is not), so want an MTU around 296. (Since TCP
122 * will send 256 byte segments (to allow for 40 byte headers), the
123 * typical packet size on the wire will be around 260 bytes). In
124 * 4.3tahoe+ systems, we can set an MTU in a route so we do that &
125 * leave the interface MTU relatively high (so we don't IP fragment
126 * when acting as a gateway to someone using a stupid MTU).
127 *
128 * Similar considerations apply to SLIP_HIWAT: It's the amount of
129 * data that will be queued 'downstream' of us (i.e., in clists
130 * waiting to be picked up by the tty output interrupt). If we
131 * queue a lot of data downstream, it's immune to our t.o.s. queuing.
132 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
133 * telnet/ftp will see a 1 sec wait, independent of the mtu (the
134 * wait is dependent on the ftp window size but that's typically
135 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize
136 * the cost (in idle time on the wire) of the tty driver running
137 * off the end of its clists & having to call back slstart for a
138 * new packet. For a tty interface with any buffering at all, this
139 * cost will be zero. Even with a totally brain dead interface (like
140 * the one on a typical workstation), the cost will be <= 1 character
141 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
142 * at most 1% while maintaining good interactive response.
143 */
144 #define BUFOFFSET 128
145 #define SLMAX (MCLBYTES - BUFOFFSET)
146 #define SLBUFSIZE (SLMAX + BUFOFFSET)
147 #define SLMTU 296
148 #define SLIP_HIWAT roundup(50, 1 /*CBSIZ*/)
149 #define CLISTRESERVE 1024 /* Can't let clists get too low */
150
151 /*
152 * SLIP ABORT ESCAPE MECHANISM:
153 * (inspired by HAYES modem escape arrangement)
154 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
155 * signals a "soft" exit from slip mode by usermode process
156 */
157
158 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/
159 #define ABT_WAIT 1 /* in seconds - idle before an escape & after */
160 #define ABT_RECYCLE (5*2+2) /* in seconds - time window processing abort */
161
162 #define ABT_SOFT 3 /* count of escapes */
163
164
165 /*
166 * The following disgusting hack gets around the problem that IP TOS
167 * can't be set yet. We want to put "interactive" traffic on a high
168 * priority queue. To decide if traffic is interactive, we check that
169 * a) it is TCP and b) one of its ports is telnet, rlogin or ftp control.
170 */
171 static u_short interactive_ports[8] = {
172 0, 513, 0, 0,
173 0, 21, 0, 23,
174 };
175 #define INTERACTIVE(p) (interactive_ports[(p) & 7] == (p))
176
177 static int nsl;
178 static struct sl_softc *sl_softc;
179
180 #define FRAME_END 0xc0 /* Frame End */
181 #define FRAME_ESCAPE 0xdb /* Frame Esc */
182 #define TRANS_FRAME_END 0xdc /* transposed frame end */
183 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */
184
185 #define t_sc T_LINEP
186
187 static int sloutput() , slioctl();
188 static void slstart(struct tty *tp);
189 static slattach();
190 extern struct timeval time;
191
192 /* execute on load/bootstrap to configure in */
SLIP_MODCONFIG()193 SLIP_MODCONFIG() {
194 slattach();
195 }
196
197 /*
198 * Called from boot code to establish sl interfaces.
199 */
200 static
slattach()201 slattach()
202 {
203 struct sl_softc *sc;
204 int i = 0;
205
206 for (sc = sl_softc; i < nsl; sc++) {
207 sc->sc_if.if_name = "sl";
208 sc->sc_if.if_unit = i++;
209 sc->sc_if.if_mtu = SLMTU;
210 sc->sc_if.if_flags = IFF_POINTOPOINT;
211 sc->sc_if.if_type = IFT_SLIP;
212 sc->sc_if.if_ioctl = slioctl;
213 sc->sc_if.if_output = sloutput;
214 sc->sc_if.if_snd.ifq_maxlen = 50;
215 sc->sc_fastq.ifq_maxlen = 32;
216 if_attach(&sc->sc_if);
217 }
218 }
219
220 static int
slinit(sc)221 slinit(sc)
222 struct sl_softc *sc;
223 {
224 caddr_t p;
225
226 if (sc->sc_ep == (u_char *) 0) {
227 MCLALLOC(p, M_WAIT);
228 if (p)
229 sc->sc_ep = (u_char *)p + SLBUFSIZE;
230 else {
231 printf("sl%d: can't allocate buffer\n", sc - sl_softc);
232 sc->sc_if.if_flags &= ~IFF_UP;
233 return (0);
234 }
235 }
236 sc->sc_buf = sc->sc_ep - SLMAX;
237 sc->sc_mp = sc->sc_buf;
238 sl_compress_init(&sc->sc_comp);
239 return (1);
240 }
241
242 /*
243 * Line specific open routine.
244 * Attach the given tty to the first available sl unit.
245 */
246 /* ARGSUSED */
247 static int
slopen(dev_t dev,struct tty * tp,int flag)248 slopen(dev_t dev, struct tty *tp, int flag)
249 {
250 struct proc *p = curproc; /* XXX */
251 register struct sl_softc *sc;
252 register int ns;
253 int error;
254
255 if (error = use_priv(p->p_ucred, PRV_SLIP_OPEN, p))
256 return (error);
257
258 if (tp->t_line == SLIPDISC)
259 return (0);
260
261 for (ns = nsl, sc = sl_softc; --ns >= 0; sc++)
262 if (sc->sc_ttyp == NULL) {
263 if (slinit(sc) == 0)
264 return (ENOBUFS);
265 tp->t_sc = (caddr_t)sc;
266 sc->sc_ttyp = tp;
267 sc->sc_if.if_baudrate = tp->t_ospeed;
268 ttyflush(tp, FREAD | FWRITE);
269 return (0);
270 }
271 return (ENXIO);
272 }
273
274 /*
275 * Line specific close routine.
276 * Detach the tty from the sl unit.
277 * Mimics part of ttyclose().
278 */
279 static void
slclose(struct tty * tp,int flag)280 slclose(struct tty *tp, int flag)
281 {
282 register struct sl_softc *sc;
283 int s;
284
285 ttywflush(tp);
286 s = splimp(); /* actually, max(spltty, splnet) */
287 tp->t_line = 0;
288 sc = (struct sl_softc *)tp->t_sc;
289 if (sc != NULL) {
290 if_down(&sc->sc_if);
291 sc->sc_ttyp = NULL;
292 tp->t_sc = NULL;
293 MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE));
294 sc->sc_ep = 0;
295 sc->sc_mp = 0;
296 sc->sc_buf = 0;
297 }
298 splx(s);
299 }
300
301 /*
302 * Line specific (tty) ioctl routine.
303 * Provide a way to get the sl unit number.
304 */
305 /* ARGSUSED */
306 static int
sltioctl(struct tty * tp,int cmd,caddr_t data,int flag,struct proc * p)307 sltioctl(struct tty *tp, int cmd, caddr_t data, int flag, struct proc *p)
308 {
309 struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
310 int s;
311
312 switch (cmd) {
313 case SLIOCGUNIT:
314 *(int *)data = sc->sc_if.if_unit;
315 break;
316
317 case SLIOCGFLAGS:
318 *(int *)data = sc->sc_flags;
319 break;
320
321 case SLIOCSFLAGS:
322 #define SC_MASK 0xffff
323 s = splimp();
324 sc->sc_flags =
325 (sc->sc_flags &~ SC_MASK) | ((*(int *)data) & SC_MASK);
326 splx(s);
327 break;
328
329 default:
330 return (-1);
331 }
332 return (0);
333 }
334
335 /*
336 * Queue a packet. Start transmission if not active.
337 */
338 static
339 sloutput(ifp, m, dst)
340 struct ifnet *ifp;
341 register struct mbuf *m;
342 struct sockaddr *dst;
343 {
344 register struct sl_softc *sc = &sl_softc[ifp->if_unit];
345 register struct ip *ip;
346 register struct ifqueue *ifq;
347 int s;
348
349 /*
350 * `Cannot happen' (see slioctl). Someday we will extend
351 * the line protocol to support other address families.
352 */
353 if (dst->sa_family != AF_INET) {
354 printf("sl%d: af%d not supported\n", sc->sc_if.if_unit,
355 dst->sa_family);
356 m_freem(m);
357 return (EAFNOSUPPORT);
358 }
359
360 if (sc->sc_ttyp == NULL) {
361 m_freem(m);
362 return (ENETDOWN); /* sort of */
363 }
364 if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0) {
365 m_freem(m);
366 return (EHOSTUNREACH);
367 }
368 ifq = &sc->sc_if.if_snd;
369 if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) {
370 register int p = ((int *)ip)[ip->ip_hl];
371
372 if (INTERACTIVE(p & 0xffff) || INTERACTIVE(p >> 16)) {
373 ifq = &sc->sc_fastq;
374 p = 1;
375 } else
376 p = 0;
377
378 if (sc->sc_flags & SC_COMPRESS) {
379 /*
380 * The last parameter turns off connection id
381 * compression for background traffic: Since
382 * fastq traffic can jump ahead of the background
383 * traffic, we don't know what order packets will
384 * go on the line.
385 */
386 p = sl_compress_tcp(m, ip, &sc->sc_comp, p);
387 *mtod(m, u_char *) |= p;
388 }
389 } else if (sc->sc_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
390 m_freem(m);
391 return (0);
392 }
393 s = splimp();
394 if (IF_QFULL(ifq)) {
395 IF_DROP(ifq);
396 m_freem(m);
397 splx(s);
398 sc->sc_if.if_oerrors++;
399 return (ENOBUFS);
400 }
401 IF_ENQUEUE(ifq, m);
402 sc->sc_if.if_lastchange = time;
403 if (RB_LEN(&sc->sc_ttyp->t_out) == 0)
404 slstart(sc->sc_ttyp);
405 splx(s);
406 return (0);
407 }
408
409 /*
410 * Start output on interface. Get another datagram
411 * to send from the interface queue and map it to
412 * the interface before starting output.
413 */
414 static void
slstart(struct tty * tp)415 slstart(struct tty *tp)
416 {
417 register struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
418 register struct mbuf *m;
419 register u_char *cp;
420 int s;
421 struct mbuf *m2;
422
423 for (;;) {
424 /*
425 * If there is more in the output queue, just send it now.
426 * We are being called in lieu of ttstart and must do what
427 * it would.
428 */
429 if (RB_LEN(&tp->t_out) != 0) {
430 (*tp->t_oproc)(tp);
431 if (RB_LEN(&tp->t_out) > SLIP_HIWAT)
432 return;
433 }
434 /*
435 * This happens briefly when the line shuts down.
436 */
437 if (sc == NULL)
438 return;
439
440 /*
441 * Get a packet and send it to the interface.
442 */
443 s = splimp();
444 IF_DEQUEUE(&sc->sc_fastq, m);
445 if (m == NULL)
446 IF_DEQUEUE(&sc->sc_if.if_snd, m);
447 splx(s);
448 if (m == NULL)
449 return;
450 sc->sc_if.if_lastchange = time;
451 /*
452 * If system is getting low on clists, just flush our
453 * output queue (if the stuff was important, it'll get
454 * retransmitted).
455 */
456 if (RBSZ - RB_LEN(&tp->t_out) < SLMTU) {
457 m_freem(m);
458 sc->sc_if.if_collisions++;
459 continue;
460 }
461
462 /*
463 * The extra FRAME_END will start up a new packet, and thus
464 * will flush any accumulated garbage. We do this whenever
465 * the line may have been idle for some time.
466 */
467 if (RB_LEN(&tp->t_out) == 0) {
468 ++sc->sc_bytessent;
469 (void) putc(FRAME_END, &tp->t_out);
470 }
471
472 while (m) {
473 register u_char *ep;
474
475 cp = mtod(m, u_char *); ep = cp + m->m_len;
476 while (cp < ep) {
477 /*
478 * Find out how many bytes in the string we can
479 * handle without doing something special.
480 */
481 register u_char *bp = cp;
482
483 while (cp < ep) {
484 switch (*cp++) {
485 case FRAME_ESCAPE:
486 case FRAME_END:
487 --cp;
488 goto out;
489 }
490 }
491 out:
492 if (cp > bp) {
493 int cc;
494 /*
495 * Put n characters at once
496 * into the tty output queue.
497 */
498 #ifdef was
499 if (b_to_q((char *)bp, cp - bp, &tp->t_outq))
500 break;
501 sc->sc_bytessent += cp - bp;
502 #else
503 #ifdef works
504 if (cc = RB_CONTIGPUT(&tp->t_out)) {
505 cc = min (cc, cp - bp);
506 memcpy(tp->t_out.rb_tl,
507 (char *)bp, cc);
508 tp->t_out.rb_tl =
509 RB_ROLLOVER(&tp->t_out, tp->t_out.rb_tl + cc);
510 sc->sc_bytessent += cc;
511 bp += cc;
512 } else
513 break;
514 if (cp > bp && cc = RB_CONTIGPUT(&tp->t_out)) {
515 cc = min (cc, cp - bp);
516 memcpy(tp->t_out.rb_tl,
517 (char *)bp, cc);
518 tp->t_out.rb_tl =
519 RB_ROLLOVER(&tp->t_out, tp->t_out.rb_tl + cc);
520 sc->sc_bytessent += cc;
521 bp += cc;
522 } else
523 break;
524 #else
525 while (cp > bp && (cc = RB_CONTIGPUT(&tp->t_out))) {
526 cc = min (cc, cp - bp);
527 memcpy(tp->t_out.rb_tl,
528 (char *)bp, cc);
529 tp->t_out.rb_tl =
530 RB_ROLLOVER(&tp->t_out, tp->t_out.rb_tl + cc);
531 sc->sc_bytessent += cc;
532 bp += cc;
533 }
534 #endif
535 #endif
536 }
537 /*
538 * If there are characters left in the mbuf,
539 * the first one must be special..
540 * Put it out in a different form.
541 */
542 if (cp < ep) {
543 if (putc(FRAME_ESCAPE, &tp->t_out))
544 break;
545 if (putc(*cp++ == FRAME_ESCAPE ?
546 TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
547 &tp->t_out)) {
548 (void) unputc(&tp->t_out);
549 break;
550 }
551 sc->sc_bytessent += 2;
552 }
553 }
554 MFREE(m, m2);
555 m = m2;
556 }
557
558 if (putc(FRAME_END, &tp->t_out)) {
559 /*
560 * Not enough room. Remove a char to make room
561 * and end the packet normally.
562 * If you get many collisions (more than one or two
563 * a day) you probably do not have enough clists
564 * and you should increase "nclist" in param.c.
565 */
566 (void) unputc(&tp->t_out);
567 (void) putc(FRAME_END, &tp->t_out);
568 sc->sc_if.if_collisions++;
569 } else {
570 ++sc->sc_bytessent;
571 sc->sc_if.if_opackets++;
572 }
573 sc->sc_if.if_obytes = sc->sc_bytessent;
574 }
575 }
576
577 /*
578 * Copy data buffer to mbuf chain; add ifnet pointer.
579 */
580 static struct mbuf *
sl_btom(sc,len)581 sl_btom(sc, len)
582 register struct sl_softc *sc;
583 register int len;
584 {
585 register struct mbuf *m;
586
587 MGETHDR(m, M_DONTWAIT, MT_DATA);
588 if (m == NULL)
589 return (NULL);
590
591 /*
592 * If we have more than MHLEN bytes, it's cheaper to
593 * queue the cluster we just filled & allocate a new one
594 * for the input buffer. Otherwise, fill the mbuf we
595 * allocated above. Note that code in the input routine
596 * guarantees that packet will fit in a cluster.
597 */
598 if (len >= MHLEN) {
599 MCLGET(m, M_DONTWAIT);
600 if ((m->m_flags & M_EXT) == 0) {
601 /*
602 * we couldn't get a cluster - if memory's this
603 * low, it's time to start dropping packets.
604 */
605 (void) m_free(m);
606 return (NULL);
607 }
608 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
609 m->m_data = (caddr_t)sc->sc_buf;
610 m->m_ext.ext_buf = (caddr_t)((int)sc->sc_buf &~ MCLOFSET);
611 } else
612 memcpy(mtod(m, caddr_t), (caddr_t)sc->sc_buf, len);
613
614 m->m_len = len;
615 m->m_pkthdr.len = len;
616 m->m_pkthdr.rcvif = &sc->sc_if;
617 return (m);
618 }
619
620 /*
621 * tty interface receiver interrupt.
622 */
623 static void
slinput(unsigned c,struct tty * tp)624 slinput(unsigned c, struct tty *tp)
625 {
626 register struct sl_softc *sc;
627 register struct mbuf *m;
628 register int len;
629 int s;
630
631 tk_nin++;
632 sc = (struct sl_softc *)tp->t_sc;
633 if (sc == NULL)
634 return;
635 if (!(tp->t_state&TS_CARR_ON)) /* XXX */
636 return;
637
638 ++sc->sc_bytesrcvd;
639 ++sc->sc_if.if_ibytes;
640 c &= 0xff; /* XXX */
641
642 #ifdef ABT_ESC
643 if (sc->sc_flags & SC_ABORT) {
644 /* if we see an abort after "idle" time, count it */
645 if (c == ABT_ESC && time.tv_sec >= sc->sc_lasttime + ABT_WAIT) {
646 sc->sc_abortcount++;
647 /* record when the first abort escape arrived */
648 if (sc->sc_abortcount == 1)
649 sc->sc_starttime = time.tv_sec;
650 }
651 /*
652 * if we have an abort, see that we have not run out of time,
653 * or that we have an "idle" time after the complete escape
654 * sequence
655 */
656 if (sc->sc_abortcount) {
657 if (time.tv_sec >= sc->sc_starttime + ABT_RECYCLE)
658 sc->sc_abortcount = 0;
659 if (sc->sc_abortcount >= ABT_SOFT &&
660 time.tv_sec >= sc->sc_lasttime + ABT_WAIT) {
661 slclose(tp, 0);
662 return;
663 }
664 }
665 sc->sc_lasttime = time.tv_sec;
666 }
667 #endif
668
669 switch (c) {
670
671 case TRANS_FRAME_ESCAPE:
672 if (sc->sc_escape)
673 c = FRAME_ESCAPE;
674 break;
675
676 case TRANS_FRAME_END:
677 if (sc->sc_escape)
678 c = FRAME_END;
679 break;
680
681 case FRAME_ESCAPE:
682 sc->sc_escape = 1;
683 return;
684
685 case FRAME_END:
686 len = sc->sc_mp - sc->sc_buf;
687 if (len < 3)
688 /* less than min length packet - ignore */
689 goto newpack;
690
691 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
692 if (c & 0x80)
693 c = TYPE_COMPRESSED_TCP;
694 else if (c == TYPE_UNCOMPRESSED_TCP)
695 *sc->sc_buf &= 0x4f; /* XXX */
696 /*
697 * We've got something that's not an IP packet.
698 * If compression is enabled, try to decompress it.
699 * Otherwise, if `auto-enable' compression is on and
700 * it's a reasonable packet, decompress it and then
701 * enable compression. Otherwise, drop it.
702 */
703 if (sc->sc_flags & SC_COMPRESS) {
704 len = sl_uncompress_tcp(&sc->sc_buf, len, len,
705 (u_int)c, &sc->sc_comp);
706 if (len <= 0)
707 goto error;
708 } else if ((sc->sc_flags & SC_AUTOCOMP) &&
709 c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
710 len = sl_uncompress_tcp(&sc->sc_buf, len, len,
711 (u_int)c, &sc->sc_comp);
712 if (len <= 0)
713 goto error;
714 sc->sc_flags |= SC_COMPRESS;
715 } else
716 goto error;
717 }
718 m = sl_btom(sc, len);
719 if (m == NULL)
720 goto error;
721
722 sc->sc_if.if_ipackets++;
723 sc->sc_if.if_lastchange = time;
724 s = splimp();
725 if (IF_QFULL(&ipintrq)) {
726 IF_DROP(&ipintrq);
727 sc->sc_if.if_ierrors++;
728 sc->sc_if.if_iqdrops++;
729 m_freem(m);
730 } else {
731 IF_ENQUEUE(&ipintrq, m);
732 schednetisr(NETISR_IP);
733 }
734 splx(s);
735 goto newpack;
736 }
737 if (sc->sc_mp < sc->sc_ep) {
738 *sc->sc_mp++ = c;
739 sc->sc_escape = 0;
740 return;
741 }
742 error:
743 sc->sc_if.if_ierrors++;
744 newpack:
745 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLMAX;
746 sc->sc_escape = 0;
747 }
748
749 /*
750 * Process an ioctl request.
751 */
752 static
slioctl(ifp,cmd,data)753 slioctl(ifp, cmd, data)
754 register struct ifnet *ifp;
755 int cmd;
756 caddr_t data;
757 {
758 register struct ifaddr *ifa = (struct ifaddr *)data;
759 int s = splimp(), error = 0;
760
761 switch (cmd) {
762
763 case SIOCSIFADDR:
764 if (ifa->ifa_addr->sa_family == AF_INET)
765 ifp->if_flags |= IFF_UP;
766 else
767 error = EAFNOSUPPORT;
768 break;
769
770 case SIOCSIFDSTADDR:
771 if (ifa->ifa_addr->sa_family != AF_INET)
772 error = EAFNOSUPPORT;
773 break;
774
775 default:
776 error = EINVAL;
777 }
778 splx(s);
779 return (error);
780 }
781
782 int ldiscif_config(char **cfg, struct ldiscif *lif);
783 static struct ldiscif sl_ldiscif =
784 {
785 {0}, -1, 0, 0, 0,
786 slopen, slclose, 0, 0, sltioctl, slinput, 0, slstart, nullmodem,
787 };
788
LDISC_MODCONFIG()789 LDISC_MODCONFIG() {
790 char *cfg_string = sl_config;
791
792 if (ldiscif_config(&cfg_string, &sl_ldiscif) == 0)
793 return;
794
795 /* allocate number of slip interfaces */
796 nsl = 1;
797 (void)cfg_number(&cfg_string, &nsl);
798
799 sl_softc = (struct sl_softc *)
800 malloc(sizeof(struct sl_softc) * nsl, M_TEMP, M_NOWAIT);
801 (void)memset((void *)sl_softc, 0, sizeof (struct sl_softc) * nsl);
802 }
803