if_sl.c revision 1.75 
1/*	$NetBSD: if_sl.c,v 1.75 2001/05/30 16:42:02 itojun Exp $	*/
2
3/*
4 * Copyright (c) 1987, 1989, 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 *	@(#)if_sl.c	8.9 (Berkeley) 1/9/95
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
66#include "sl.h"
67#if NSL > 0
68
69#include "opt_inet.h"
70#include "bpfilter.h"
71
72#include <sys/param.h>
73#include <sys/proc.h>
74#include <sys/malloc.h>
75#include <sys/mbuf.h>
76#include <sys/buf.h>
77#include <sys/dkstat.h>
78#include <sys/socket.h>
79#include <sys/ioctl.h>
80#include <sys/file.h>
81#include <sys/conf.h>
82#include <sys/tty.h>
83#include <sys/kernel.h>
84#if __NetBSD__
85#include <sys/systm.h>
86#endif
87
88#include <machine/cpu.h>
89#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
90#include <machine/intr.h>
91#endif
92
93#include <net/if.h>
94#include <net/if_types.h>
95#include <net/netisr.h>
96#include <net/route.h>
97
98#ifdef INET
99#include <netinet/in.h>
100#include <netinet/in_systm.h>
101#include <netinet/in_var.h>
102#include <netinet/ip.h>
103#else
104#error Slip without inet?
105#endif
106
107#include <net/slcompress.h>
108#include <net/if_slvar.h>
109#include <net/slip.h>
110
111#if NBPFILTER > 0
112#include <sys/time.h>
113#include <net/bpf.h>
114#endif
115
116/*
117 * SLMAX 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, SLMAX can be at most
122 *	MCLBYTES - 128
123 *
124 * SLMTU is a hard limit on output packet size.  To insure good
125 * interactive response, SLMTU wants to be the smallest size that
126 * amortizes the header cost.  (Remember that even with
127 * type-of-service queuing, we have to wait for any in-progress
128 * packet to finish.  I.e., we wait, on the average, 1/2 * mtu /
129 * cps, where cps is the line speed in characters per second.
130 * E.g., 533ms wait for a 1024 byte MTU on a 9600 baud line.  The
131 * average compressed header size is 6-8 bytes so any MTU > 90
132 * bytes will give us 90% of the line bandwidth.  A 100ms wait is
133 * tolerable (500ms is not), so want an MTU around 296.  (Since TCP
134 * will send 256 byte segments (to allow for 40 byte headers), the
135 * typical packet size on the wire will be around 260 bytes).  In
136 * 4.3tahoe+ systems, we can set an MTU in a route so we do that &
137 * leave the interface MTU relatively high (so we don't IP fragment
138 * when acting as a gateway to someone using a stupid MTU).
139 *
140 * Similar considerations apply to SLIP_HIWAT:  It's the amount of
141 * data that will be queued 'downstream' of us (i.e., in clists
142 * waiting to be picked up by the tty output interrupt).  If we
143 * queue a lot of data downstream, it's immune to our t.o.s. queuing.
144 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
145 * telnet/ftp will see a 1 sec wait, independent of the mtu (the
146 * wait is dependent on the ftp window size but that's typically
147 * 1k - 4k).  So, we want SLIP_HIWAT just big enough to amortize
148 * the cost (in idle time on the wire) of the tty driver running
149 * off the end of its clists & having to call back slstart for a
150 * new packet.  For a tty interface with any buffering at all, this
151 * cost will be zero.  Even with a totally brain dead interface (like
152 * the one on a typical workstation), the cost will be <= 1 character
153 * time.  So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
154 * at most 1% while maintaining good interactive response.
155 */
156#define	BUFOFFSET	(128+sizeof(struct ifnet **)+SLIP_HDRLEN)
157#define	SLMAX		(MCLBYTES - BUFOFFSET)
158#define	SLBUFSIZE	(SLMAX + BUFOFFSET)
159#ifndef SLMTU
160#define	SLMTU		296
161#endif
162#if (SLMTU < 3)
163#error SLMTU way too small.
164#endif
165#define	SLIP_HIWAT	roundup(50,CBSIZE)
166#ifndef __NetBSD__					/* XXX - cgd */
167#define	CLISTRESERVE	1024	/* Can't let clists get too low */
168#endif	/* !__NetBSD__ */
169
170/*
171 * SLIP ABORT ESCAPE MECHANISM:
172 *	(inspired by HAYES modem escape arrangement)
173 *	1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
174 *	within window time signals a "soft" exit from slip mode by remote end
175 *	if the IFF_DEBUG flag is on.
176 */
177#define	ABT_ESC		'\033'	/* can't be t_intr - distant host must know it*/
178#define	ABT_IDLE	1	/* in seconds - idle before an escape */
179#define	ABT_COUNT	3	/* count of escapes for abort */
180#define	ABT_WINDOW	(ABT_COUNT*2+2)	/* in seconds - time to count */
181
182struct sl_softc sl_softc[NSL];
183
184#define FRAME_END	 	0xc0		/* Frame End */
185#define FRAME_ESCAPE		0xdb		/* Frame Esc */
186#define TRANS_FRAME_END	 	0xdc		/* transposed frame end */
187#define TRANS_FRAME_ESCAPE 	0xdd		/* transposed frame esc */
188
189#ifndef __HAVE_GENERIC_SOFT_INTERRUPTS
190void	slnetisr(void);
191#endif
192void	slintr(void *);
193
194static int slinit __P((struct sl_softc *));
195static struct mbuf *sl_btom __P((struct sl_softc *, int));
196
197/*
198 * Called from boot code to establish sl interfaces.
199 */
200void
201slattach()
202{
203	struct sl_softc *sc;
204	int i = 0;
205
206	for (sc = sl_softc; i < NSL; sc++) {
207		sc->sc_unit = i;		/* XXX */
208		sprintf(sc->sc_if.if_xname, "sl%d", i++);
209		sc->sc_if.if_softc = sc;
210		sc->sc_if.if_mtu = SLMTU;
211		sc->sc_if.if_flags =
212		    IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
213		sc->sc_if.if_type = IFT_SLIP;
214		sc->sc_if.if_ioctl = slioctl;
215		sc->sc_if.if_output = sloutput;
216		sc->sc_if.if_dlt = DLT_SLIP;
217		sc->sc_fastq.ifq_maxlen = 32;
218		IFQ_SET_READY(&sc->sc_if.if_snd);
219		if_attach(&sc->sc_if);
220		if_alloc_sadl(&sc->sc_if);
221#if NBPFILTER > 0
222		bpfattach(&sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
223#endif
224	}
225}
226
227static int
228slinit(sc)
229	struct sl_softc *sc;
230{
231
232	if (sc->sc_mbuf == NULL) {
233		MGETHDR(sc->sc_mbuf, M_WAIT, MT_DATA);
234		MCLGET(sc->sc_mbuf, M_WAIT);
235	}
236	sc->sc_ep = (u_char *) sc->sc_mbuf->m_ext.ext_buf +
237	    sc->sc_mbuf->m_ext.ext_size;
238	sc->sc_mp = sc->sc_pktstart = (u_char *) sc->sc_mbuf->m_ext.ext_buf +
239	    BUFOFFSET;
240
241	sl_compress_init(&sc->sc_comp);
242
243	return (1);
244}
245
246/*
247 * Line specific open routine.
248 * Attach the given tty to the first available sl unit.
249 */
250/* ARGSUSED */
251int
252slopen(dev, tp)
253	dev_t dev;
254	struct tty *tp;
255{
256	struct proc *p = curproc;		/* XXX */
257	struct sl_softc *sc;
258	int nsl;
259	int error;
260	int s;
261
262	if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
263		return (error);
264
265	if (tp->t_linesw->l_no == SLIPDISC)
266		return (0);
267
268	for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++)
269		if (sc->sc_ttyp == NULL) {
270#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
271			sc->sc_si = softintr_establish(IPL_SOFTNET,
272			    slintr, sc);
273			if (sc->sc_si == NULL)
274				return (ENOMEM);
275#endif
276			if (slinit(sc) == 0) {
277#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
278				softintr_disestablish(sc->sc_si);
279#endif
280				return (ENOBUFS);
281			}
282			tp->t_sc = (caddr_t)sc;
283			sc->sc_ttyp = tp;
284			sc->sc_if.if_baudrate = tp->t_ospeed;
285			s = spltty();
286			tp->t_state |= TS_ISOPEN | TS_XCLUDE;
287			splx(s);
288			ttyflush(tp, FREAD | FWRITE);
289#ifdef __NetBSD__
290			/*
291			 * make sure tty output queue is large enough
292			 * to hold a full-sized packet (including frame
293			 * end, and a possible extra frame end).  full-sized
294			 * packet occupies a max of 2*SLMAX bytes (because
295			 * of possible escapes), and add two on for frame
296			 * ends.
297			 */
298			s = spltty();
299			if (tp->t_outq.c_cn < 2*SLMAX+2) {
300				sc->sc_oldbufsize = tp->t_outq.c_cn;
301				sc->sc_oldbufquot = tp->t_outq.c_cq != 0;
302
303				clfree(&tp->t_outq);
304				error = clalloc(&tp->t_outq, 2*SLMAX+2, 0);
305				if (error) {
306					splx(s);
307#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
308					softintr_disestablish(sc->sc_si);
309#endif
310					return(error);
311				}
312			} else
313				sc->sc_oldbufsize = sc->sc_oldbufquot = 0;
314			splx(s);
315#endif /* __NetBSD__ */
316			return (0);
317		}
318	return (ENXIO);
319}
320
321/*
322 * Line specific close routine.
323 * Detach the tty from the sl unit.
324 */
325void
326slclose(tp)
327	struct tty *tp;
328{
329	struct sl_softc *sc;
330	int s;
331
332	ttywflush(tp);
333	sc = tp->t_sc;
334
335	if (sc != NULL) {
336#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
337		softintr_disestablish(sc->sc_si);
338#endif
339		s = splnet();
340		if_down(&sc->sc_if);
341		IF_PURGE(&sc->sc_fastq);
342		splx(s);
343
344		s = spltty();
345		tp->t_linesw = linesw[0];	/* default line disc. */
346		tp->t_state = 0;
347
348		sc->sc_ttyp = NULL;
349		tp->t_sc = NULL;
350
351		m_freem(sc->sc_mbuf);
352		sc->sc_mbuf = NULL;
353		sc->sc_ep = sc->sc_mp = sc->sc_pktstart = NULL;
354		IF_PURGE(&sc->sc_inq);
355
356		/*
357		 * If necessary, install a new outq buffer of the
358		 * appropriate size.
359		 */
360		if (sc->sc_oldbufsize != 0) {
361			clfree(&tp->t_outq);
362			clalloc(&tp->t_outq, sc->sc_oldbufsize,
363			    sc->sc_oldbufquot);
364		}
365		splx(s);
366	}
367}
368
369/*
370 * Line specific (tty) ioctl routine.
371 * Provide a way to get the sl unit number.
372 */
373/* ARGSUSED */
374int
375sltioctl(tp, cmd, data, flag)
376	struct tty *tp;
377	u_long cmd;
378	caddr_t data;
379	int flag;
380{
381	struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
382
383	switch (cmd) {
384	case SLIOCGUNIT:
385		*(int *)data = sc->sc_unit;	/* XXX */
386		break;
387
388	default:
389		return (-1);
390	}
391	return (0);
392}
393
394/*
395 * Queue a packet.  Start transmission if not active.
396 * Compression happens in slintr(); if we do it here, IP TOS
397 * will cause us to not compress "background" packets, because
398 * ordering gets trashed.  It can be done for all packets in slintr().
399 */
400int
401sloutput(ifp, m, dst, rtp)
402	struct ifnet *ifp;
403	struct mbuf *m;
404	struct sockaddr *dst;
405	struct rtentry *rtp;
406{
407	struct sl_softc *sc = ifp->if_softc;
408	struct ip *ip;
409	int s, error;
410	ALTQ_DECL(struct altq_pktattr pktattr;)
411
412	IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family, &pktattr);
413
414	/*
415	 * `Cannot happen' (see slioctl).  Someday we will extend
416	 * the line protocol to support other address families.
417	 */
418	if (dst->sa_family != AF_INET) {
419		printf("%s: af%d not supported\n", sc->sc_if.if_xname,
420		    dst->sa_family);
421		m_freem(m);
422		sc->sc_if.if_noproto++;
423		return (EAFNOSUPPORT);
424	}
425
426	if (sc->sc_ttyp == NULL) {
427		m_freem(m);
428		return (ENETDOWN);	/* sort of */
429	}
430	if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0 &&
431	    (sc->sc_ttyp->t_cflag & CLOCAL) == 0) {
432		m_freem(m);
433		printf("%s: no carrier and not local\n", sc->sc_if.if_xname);
434		return (EHOSTUNREACH);
435	}
436	ip = mtod(m, struct ip *);
437	if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
438		m_freem(m);
439		return (ENETRESET);		/* XXX ? */
440	}
441
442	s = spltty();
443	if (sc->sc_oqlen && sc->sc_ttyp->t_outq.c_cc == sc->sc_oqlen) {
444		struct timeval tv;
445
446		/* if output's been stalled for too long, and restart */
447		timersub(&time, &sc->sc_if.if_lastchange, &tv);
448		if (tv.tv_sec > 0) {
449			sc->sc_otimeout++;
450			slstart(sc->sc_ttyp);
451		}
452	}
453	splx(s);
454
455	s = splnet();
456	if ((ip->ip_tos & IPTOS_LOWDELAY) != 0
457#ifdef ALTQ
458	    && ALTQ_IS_ENABLED(&ifp->if_snd) == 0
459#endif
460	    ) {
461		if (IF_QFULL(&sc->sc_fastq)) {
462			IF_DROP(&sc->sc_fastq);
463			m_freem(m);
464			error = ENOBUFS;
465		} else {
466			IF_ENQUEUE(&sc->sc_fastq, m);
467			error = 0;
468		}
469	} else
470		IFQ_ENQUEUE(&ifp->if_snd, m, &pktattr, error);
471	if (error) {
472		splx(s);
473		ifp->if_oerrors++;
474		return (error);
475	}
476	sc->sc_if.if_lastchange = time;
477	splx(s);
478
479	s = spltty();
480	if ((sc->sc_oqlen = sc->sc_ttyp->t_outq.c_cc) == 0)
481		slstart(sc->sc_ttyp);
482	splx(s);
483
484	return (0);
485}
486
487/*
488 * Start output on interface.  Get another datagram
489 * to send from the interface queue and map it to
490 * the interface before starting output.
491 */
492void
493slstart(tp)
494	struct tty *tp;
495{
496	struct sl_softc *sc = tp->t_sc;
497
498	/*
499	 * If there is more in the output queue, just send it now.
500	 * We are being called in lieu of ttstart and must do what
501	 * it would.
502	 */
503	if (tp->t_outq.c_cc != 0) {
504		(*tp->t_oproc)(tp);
505		if (tp->t_outq.c_cc > SLIP_HIWAT)
506			return;
507	}
508
509	/*
510	 * This happens briefly when the line shuts down.
511	 */
512	if (sc == NULL)
513		return;
514#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
515	softintr_schedule(sc->sc_si);
516#else
517    {
518	int s = splhigh();
519	schednetisr(NETISR_SLIP);
520	splx(s);
521    }
522#endif
523}
524
525/*
526 * Copy data buffer to mbuf chain; add ifnet pointer.
527 */
528static struct mbuf *
529sl_btom(sc, len)
530	struct sl_softc *sc;
531	int len;
532{
533	struct mbuf *m;
534
535	/*
536	 * Allocate a new input buffer and swap.
537	 */
538	m = sc->sc_mbuf;
539	MGETHDR(sc->sc_mbuf, M_DONTWAIT, MT_DATA);
540	if (sc->sc_mbuf == NULL) {
541		sc->sc_mbuf = m;
542		return (NULL);
543	}
544	MCLGET(sc->sc_mbuf, M_DONTWAIT);
545	if ((sc->sc_mbuf->m_flags & M_EXT) == 0) {
546		m_freem(sc->sc_mbuf);
547		sc->sc_mbuf = m;
548		return (NULL);
549	}
550	sc->sc_ep = (u_char *) sc->sc_mbuf->m_ext.ext_buf +
551	    sc->sc_mbuf->m_ext.ext_size;
552
553	m->m_data = sc->sc_pktstart;
554
555	m->m_pkthdr.len = m->m_len = len;
556	m->m_pkthdr.rcvif = &sc->sc_if;
557	return (m);
558}
559
560/*
561 * tty interface receiver interrupt.
562 */
563void
564slinput(c, tp)
565	int c;
566	struct tty *tp;
567{
568	struct sl_softc *sc;
569	struct mbuf *m;
570	int len;
571
572	tk_nin++;
573	sc = (struct sl_softc *)tp->t_sc;
574	if (sc == NULL)
575		return;
576	if ((c & TTY_ERRORMASK) || ((tp->t_state & TS_CARR_ON) == 0 &&
577	    (tp->t_cflag & CLOCAL) == 0)) {
578		sc->sc_flags |= SC_ERROR;
579		return;
580	}
581	c &= TTY_CHARMASK;
582
583	++sc->sc_if.if_ibytes;
584
585	if (sc->sc_if.if_flags & IFF_DEBUG) {
586		if (c == ABT_ESC) {
587			/*
588			 * If we have a previous abort, see whether
589			 * this one is within the time limit.
590			 */
591			if (sc->sc_abortcount &&
592			    time.tv_sec >= sc->sc_starttime + ABT_WINDOW)
593				sc->sc_abortcount = 0;
594			/*
595			 * If we see an abort after "idle" time, count it;
596			 * record when the first abort escape arrived.
597			 */
598			if (time.tv_sec >= sc->sc_lasttime + ABT_IDLE) {
599				if (++sc->sc_abortcount == 1)
600					sc->sc_starttime = time.tv_sec;
601				if (sc->sc_abortcount >= ABT_COUNT) {
602					slclose(tp);
603					return;
604				}
605			}
606		} else
607			sc->sc_abortcount = 0;
608		sc->sc_lasttime = time.tv_sec;
609	}
610
611	switch (c) {
612
613	case TRANS_FRAME_ESCAPE:
614		if (sc->sc_escape)
615			c = FRAME_ESCAPE;
616		break;
617
618	case TRANS_FRAME_END:
619		if (sc->sc_escape)
620			c = FRAME_END;
621		break;
622
623	case FRAME_ESCAPE:
624		sc->sc_escape = 1;
625		return;
626
627	case FRAME_END:
628		if(sc->sc_flags & SC_ERROR) {
629			sc->sc_flags &= ~SC_ERROR;
630			goto newpack;
631		}
632		len = sc->sc_mp - sc->sc_pktstart;
633		if (len < 3)
634			/* less than min length packet - ignore */
635			goto newpack;
636
637		m = sl_btom(sc, len);
638		if (m == NULL)
639			goto error;
640
641		IF_ENQUEUE(&sc->sc_inq, m);
642#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
643		softintr_schedule(sc->sc_si);
644#else
645	    {
646		int s = splhigh();
647		schednetisr(NETISR_SLIP);
648		splx(s);
649	    }
650#endif
651		goto newpack;
652	}
653	if (sc->sc_mp < sc->sc_ep) {
654		*sc->sc_mp++ = c;
655		sc->sc_escape = 0;
656		return;
657	}
658
659	/* can't put lower; would miss an extra frame */
660	sc->sc_flags |= SC_ERROR;
661
662error:
663	sc->sc_if.if_ierrors++;
664newpack:
665	sc->sc_mp = sc->sc_pktstart = (u_char *) sc->sc_mbuf->m_ext.ext_buf +
666	    BUFOFFSET;
667	sc->sc_escape = 0;
668}
669
670#ifndef __HAVE_GENERIC_SOFT_INTERRUPTS
671void
672slnetisr(void)
673{
674	struct sl_softc *sc;
675	int i;
676
677	for (i = 0; i < NSL; i++) {
678		sc = &sl_softc[i];
679		if (sc->sc_ttyp == NULL)
680			continue;
681		slintr(sc);
682	}
683}
684#endif
685
686void
687slintr(void *arg)
688{
689	struct sl_softc *sc = arg;
690	struct tty *tp = sc->sc_ttyp;
691	struct mbuf *m;
692	int s, len;
693	u_char *pktstart, c;
694#if NBPFILTER > 0
695	u_char chdr[CHDR_LEN];
696#endif
697
698	KASSERT(tp != NULL);
699
700	/*
701	 * Output processing loop.
702	 */
703	for (;;) {
704		struct ip *ip;
705		struct mbuf *m2;
706#if NBPFILTER > 0
707		struct mbuf *bpf_m;
708#endif
709
710		/*
711		 * Do not remove the packet from the queue if it
712		 * doesn't look like it will fit into the current
713		 * serial output queue.  With a packet full of
714		 * escapes, this could be as bad as MTU*2+2.
715		 */
716		s = spltty();
717		if (tp->t_outq.c_cn - tp->t_outq.c_cc <
718		    2*sc->sc_if.if_mtu+2) {
719			splx(s);
720			break;
721		}
722		splx(s);
723
724		/*
725		 * Get a packet and send it to the interface.
726		 */
727		s = splnet();
728		IF_DEQUEUE(&sc->sc_fastq, m);
729		if (m)
730			sc->sc_if.if_omcasts++;	/* XXX */
731		else
732			IFQ_DEQUEUE(&sc->sc_if.if_snd, m);
733		splx(s);
734
735		if (m == NULL)
736			break;
737
738		/*
739		 * We do the header compression here rather than in
740		 * sloutput() because the packets will be out of order
741		 * if we are using TOS queueing, and the connection
742		 * ID compression will get munged when this happens.
743		 */
744#if NBPFILTER > 0
745		if (sc->sc_if.if_bpf) {
746			/*
747			 * We need to save the TCP/IP header before
748			 * it's compressed.  To avoid complicated
749			 * code, we just make a deep copy of the
750			 * entire packet (since this is a serial
751			 * line, packets should be short and/or the
752			 * copy should be negligible cost compared
753			 * to the packet transmission time).
754			 */
755			bpf_m = m_dup(m, 0, M_COPYALL, M_DONTWAIT);
756		} else
757			bpf_m = NULL;
758#endif
759		if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) {
760			if (sc->sc_if.if_flags & SC_COMPRESS)
761				*mtod(m, u_char *) |=
762				    sl_compress_tcp(m, ip,
763				    &sc->sc_comp, 1);
764		}
765#if NBPFILTER > 0
766		if (sc->sc_if.if_bpf && bpf_m != NULL) {
767			/*
768			 * Put the SLIP pseudo-"link header" in
769			 * place.  The compressed header is now
770			 * at the beginning of the mbuf.
771			 */
772			struct mbuf n;
773			u_char *hp;
774
775			n.m_next = bpf_m;
776			n.m_data = n.m_dat;
777			n.m_len = SLIP_HDRLEN;
778
779			hp = mtod(&n, u_char *);
780
781			hp[SLX_DIR] = SLIPDIR_OUT;
782			memcpy(&hp[SLX_CHDR], mtod(m, caddr_t),
783			    CHDR_LEN);
784
785			s = splnet();
786			bpf_mtap(sc->sc_if.if_bpf, &n);
787			splx(s);
788			m_freem(bpf_m);
789		}
790#endif
791		sc->sc_if.if_lastchange = time;
792
793		s = spltty();
794
795		/*
796		 * The extra FRAME_END will start up a new packet,
797		 * and thus will flush any accumulated garbage.  We
798		 * do this whenever the line may have been idle for
799		 * some time.
800		 */
801		if (tp->t_outq.c_cc == 0) {
802			sc->sc_if.if_obytes++;
803			(void) putc(FRAME_END, &tp->t_outq);
804		}
805
806		while (m) {
807			u_char *bp, *cp, *ep;
808
809			bp = cp = mtod(m, u_char *);
810			ep = cp + m->m_len;
811			while (cp < ep) {
812				/*
813				 * Find out how many bytes in the
814				 * string we can handle without
815				 * doing something special.
816				 */
817				while (cp < ep) {
818					switch (*cp++) {
819					case FRAME_ESCAPE:
820					case FRAME_END:
821						cp--;
822						goto out;
823					}
824				}
825				out:
826				if (cp > bp) {
827					/*
828					 * Put N characters at once
829					 * into the tty output queue.
830					 */
831					if (b_to_q(bp, cp - bp,
832					    &tp->t_outq))
833						break;
834					sc->sc_if.if_obytes += cp - bp;
835				}
836				/*
837				 * If there are characters left in
838				 * the mbuf, the first one must be
839				 * special..  Put it out in a different
840				 * form.
841				 */
842				if (cp < ep) {
843					if (putc(FRAME_ESCAPE,
844					    &tp->t_outq))
845						break;
846					if (putc(*cp++ == FRAME_ESCAPE ?
847					    TRANS_FRAME_ESCAPE :
848					    TRANS_FRAME_END,
849					    &tp->t_outq)) {
850						(void)
851						   unputc(&tp->t_outq);
852						break;
853					}
854					sc->sc_if.if_obytes += 2;
855				}
856			}
857			MFREE(m, m2);
858			m = m2;
859		}
860
861		if (putc(FRAME_END, &tp->t_outq)) {
862			/*
863			 * Not enough room.  Remove a char to make
864			 * room and end the packet normally.  If
865			 * you get many collisions (more than one
866			 * or two a day), you probably do not have
867			 * enough clists and you should increase
868			 * "nclist" in param.c
869			 */
870			(void) unputc(&tp->t_outq);
871			(void) putc(FRAME_END, &tp->t_outq);
872			sc->sc_if.if_collisions++;
873		} else {
874			sc->sc_if.if_obytes++;
875			sc->sc_if.if_opackets++;
876		}
877
878		/*
879		 * We now have characters in the output queue,
880		 * kick the serial port.
881		 */
882		(*tp->t_oproc)(tp);
883		splx(s);
884	}
885
886	/*
887	 * Input processing loop.
888	 */
889	for (;;) {
890		s = spltty();
891		IF_DEQUEUE(&sc->sc_inq, m);
892		splx(s);
893		if (m == NULL)
894			break;
895		pktstart = mtod(m, u_char *);
896		len = m->m_pkthdr.len;
897#if NBPFILTER > 0
898		if (sc->sc_if.if_bpf) {
899			/*
900			 * Save the compressed header, so we
901			 * can tack it on later.  Note that we
902			 * will end up copying garbage in some
903			 * cases but this is okay.  We remember
904			 * where the buffer started so we can
905			 * compute the new header length.
906			 */
907			memcpy(chdr, pktstart, CHDR_LEN);
908		}
909#endif /* NBPFILTER > 0 */
910		if ((c = (*pktstart & 0xf0)) != (IPVERSION << 4)) {
911			if (c & 0x80)
912				c = TYPE_COMPRESSED_TCP;
913			else if (c == TYPE_UNCOMPRESSED_TCP)
914				*pktstart &= 0x4f; /* XXX */
915			/*
916			 * We've got something that's not an IP
917			 * packet.  If compression is enabled,
918			 * try to decompress it.  Otherwise, if
919			 * `auto-enable' compression is on and
920			 * it's a reasonable packet, decompress
921			 * it and then enable compression.
922			 * Otherwise, drop it.
923			 */
924			if (sc->sc_if.if_flags & SC_COMPRESS) {
925				len = sl_uncompress_tcp(&pktstart, len,
926				    (u_int)c, &sc->sc_comp);
927				if (len <= 0) {
928					m_freem(m);
929					continue;
930				}
931			} else if ((sc->sc_if.if_flags & SC_AUTOCOMP) &&
932			    c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
933				len = sl_uncompress_tcp(&pktstart, len,
934				    (u_int)c, &sc->sc_comp);
935				if (len <= 0) {
936					m_freem(m);
937					continue;
938				}
939				sc->sc_if.if_flags |= SC_COMPRESS;
940			} else {
941				m_freem(m);
942				continue;
943			}
944		}
945		m->m_data = (caddr_t) pktstart;
946		m->m_pkthdr.len = m->m_len = len;
947#if NBPFILTER > 0
948		if (sc->sc_if.if_bpf) {
949			/*
950			 * Put the SLIP pseudo-"link header" in place.
951			 * Note this M_PREPEND() should bever fail,
952			 * since we know we always have enough space
953			 * in the input buffer.
954			 */
955			u_char *hp;
956
957			M_PREPEND(m, SLIP_HDRLEN, M_DONTWAIT);
958			if (m == NULL)
959				continue;
960
961			hp = mtod(m, u_char *);
962			hp[SLX_DIR] = SLIPDIR_IN;
963			memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
964
965			s = splnet();
966			bpf_mtap(sc->sc_if.if_bpf, m);
967			splx(s);
968
969			m_adj(m, SLIP_HDRLEN);
970		}
971#endif /* NBPFILTER > 0 */
972		/*
973		 * If the packet will fit into a single
974		 * header mbuf, copy it into one, to save
975		 * memory.
976		 */
977		if (m->m_pkthdr.len < MHLEN) {
978			struct mbuf *n;
979
980			MGETHDR(n, M_DONTWAIT, MT_DATA);
981			M_COPY_PKTHDR(n, m);
982			memcpy(mtod(n, caddr_t), mtod(m, caddr_t),
983			    m->m_pkthdr.len);
984			n->m_len = m->m_len;
985			m_freem(m);
986			m = n;
987		}
988
989		sc->sc_if.if_ipackets++;
990		sc->sc_if.if_lastchange = time;
991
992		s = splnet();
993		if (IF_QFULL(&ipintrq)) {
994			IF_DROP(&ipintrq);
995			sc->sc_if.if_ierrors++;
996			sc->sc_if.if_iqdrops++;
997			m_freem(m);
998		} else {
999			IF_ENQUEUE(&ipintrq, m);
1000			schednetisr(NETISR_IP);
1001		}
1002		splx(s);
1003	}
1004}
1005
1006/*
1007 * Process an ioctl request.
1008 */
1009int
1010slioctl(ifp, cmd, data)
1011	struct ifnet *ifp;
1012	u_long cmd;
1013	caddr_t data;
1014{
1015	struct ifaddr *ifa = (struct ifaddr *)data;
1016	struct ifreq *ifr = (struct ifreq *)data;
1017	int s = splnet(), error = 0;
1018	struct sl_softc *sc = ifp->if_softc;
1019
1020	switch (cmd) {
1021
1022	case SIOCSIFADDR:
1023		if (ifa->ifa_addr->sa_family == AF_INET)
1024			ifp->if_flags |= IFF_UP;
1025		else
1026			error = EAFNOSUPPORT;
1027		break;
1028
1029	case SIOCSIFDSTADDR:
1030		if (ifa->ifa_addr->sa_family != AF_INET)
1031			error = EAFNOSUPPORT;
1032		break;
1033
1034	case SIOCSIFMTU:
1035		if ((ifr->ifr_mtu < 3) || (ifr->ifr_mtu > SLMAX)) {
1036		    error = EINVAL;
1037		    break;
1038		}
1039		sc->sc_if.if_mtu = ifr->ifr_mtu;
1040		break;
1041
1042	case SIOCGIFMTU:
1043		ifr->ifr_mtu = sc->sc_if.if_mtu;
1044		break;
1045
1046	case SIOCADDMULTI:
1047	case SIOCDELMULTI:
1048		if (ifr == 0) {
1049			error = EAFNOSUPPORT;		/* XXX */
1050			break;
1051		}
1052		switch (ifr->ifr_addr.sa_family) {
1053
1054#ifdef INET
1055		case AF_INET:
1056			break;
1057#endif
1058
1059		default:
1060			error = EAFNOSUPPORT;
1061			break;
1062		}
1063		break;
1064
1065	default:
1066		error = EINVAL;
1067	}
1068	splx(s);
1069	return (error);
1070}
1071#endif
1072