if_tun.c revision 15117 
1/*	$NetBSD: if_tun.c,v 1.14 1994/06/29 06:36:25 cgd Exp $	*/
2
3/*
4 * Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk>
5 * Nottingham University 1987.
6 *
7 * This source may be freely distributed, however I would be interested
8 * in any changes that are made.
9 *
10 * This driver takes packets off the IP i/f and hands them up to a
11 * user process to have it's wicked way with. This driver has it's
12 * roots in a similar driver written by Phil Cockcroft (formerly) at
13 * UCL. This driver is based much more on read/write/select mode of
14 * operation though.
15 */
16
17#include "tun.h"
18#if NTUN > 0
19
20#include <sys/param.h>
21#include <sys/proc.h>
22#include <sys/systm.h>
23#include <sys/mbuf.h>
24#include <sys/buf.h>
25#include <sys/protosw.h>
26#include <sys/socket.h>
27#include <sys/ioctl.h>
28#include <sys/errno.h>
29#include <sys/syslog.h>
30#include <sys/select.h>
31#include <sys/file.h>
32#include <sys/signalvar.h>
33#include <sys/kernel.h>
34#include <sys/sysctl.h>
35#ifdef DEVFS
36#include <sys/devfsext.h>
37#endif /*DEVFS*/
38#include <sys/conf.h>
39
40#include <net/if.h>
41#include <net/netisr.h>
42#include <net/route.h>
43
44#ifdef INET
45#include <netinet/in.h>
46#include <netinet/in_systm.h>
47#include <netinet/in_var.h>
48#include <netinet/ip.h>
49#include <netinet/if_ether.h>
50#endif
51
52#ifdef NS
53#include <netns/ns.h>
54#include <netns/ns_if.h>
55#endif
56
57#include "bpfilter.h"
58#if NBPFILTER > 0
59#include <sys/time.h>
60#include <net/bpf.h>
61#endif
62
63#include <net/if_tun.h>
64
65static void tunattach __P((void *));
66PSEUDO_SET(tunattach, if_tun);
67
68#define TUNDEBUG	if (tundebug) printf
69static int tundebug = 0;
70SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, "");
71
72static struct tun_softc tunctl[NTUN];
73
74static int tunoutput __P((struct ifnet *, struct mbuf *, struct sockaddr *,
75	    struct rtentry *rt));
76static int tunifioctl __P((struct ifnet *, int, caddr_t));
77static int tuninit __P((int));
78
79static	d_open_t	tunopen;
80static	d_close_t	tunclose;
81static	d_read_t	tunread;
82static	d_write_t	tunwrite;
83static	d_ioctl_t	tunioctl;
84static	d_select_t	tunselect;
85
86#define CDEV_MAJOR 52
87static struct cdevsw tun_cdevsw = {
88	tunopen,	tunclose,	tunread,	tunwrite,
89	tunioctl,	nullstop,	noreset,	nodevtotty,
90	tunselect,	nommap,		nostrategy,	"tun",	NULL,	-1
91};
92
93
94static tun_devsw_installed = 0;
95#ifdef	DEVFS
96static	void	*tun_devfs_token[NTUN];
97#endif
98
99static void
100tunattach(dummy)
101	void *dummy;
102{
103	register int i;
104	struct ifnet *ifp;
105	dev_t dev;
106
107	if( tun_devsw_installed ) return;
108	dev = makedev(CDEV_MAJOR, 0);
109	cdevsw_add(&dev,&tun_cdevsw, NULL);
110	tun_devsw_installed = 1;
111	for ( i = 0; i < NTUN; i++ ) {
112#ifdef DEVFS
113		tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, i, DV_CHR,
114						      UID_UUCP, GID_DIALER,
115						      0600, "tun%d", i);
116#endif
117		tunctl[i].tun_flags = TUN_INITED;
118
119		ifp = &tunctl[i].tun_if;
120		ifp->if_unit = i;
121		ifp->if_name = "tun";
122		ifp->if_mtu = TUNMTU;
123		ifp->if_ioctl = tunifioctl;
124		ifp->if_output = tunoutput;
125		ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
126		ifp->if_snd.ifq_maxlen = ifqmaxlen;
127		ifp->if_collisions = 0;
128		ifp->if_ierrors = 0;
129		ifp->if_oerrors = 0;
130		ifp->if_ipackets = 0;
131		ifp->if_opackets = 0;
132		if_attach(ifp);
133#if NBPFILTER > 0
134		bpfattach(ifp, DLT_NULL, sizeof(u_int));
135#endif
136	}
137}
138
139/*
140 * tunnel open - must be superuser & the device must be
141 * configured in
142 */
143static	int
144tunopen(dev, flag, mode, p)
145	dev_t	dev;
146	int	flag, mode;
147	struct proc *p;
148{
149	struct ifnet	*ifp;
150	struct tun_softc *tp;
151	register int	unit, error;
152
153	error = suser(p->p_ucred, &p->p_acflag);
154	if (error)
155		return (error);
156
157	if ((unit = minor(dev)) >= NTUN)
158		return (ENXIO);
159	tp = &tunctl[unit];
160	if (tp->tun_flags & TUN_OPEN)
161		return ENXIO;
162	ifp = &tp->tun_if;
163	tp->tun_flags |= TUN_OPEN;
164	TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit);
165	return (0);
166}
167
168/*
169 * tunclose - close the device - mark i/f down & delete
170 * routing info
171 */
172static	int
173tunclose(dev_t dev, int foo, int bar, struct proc *p)
174{
175	register int	unit = minor(dev), s;
176	struct tun_softc *tp = &tunctl[unit];
177	struct ifnet	*ifp = &tp->tun_if;
178	struct mbuf	*m;
179
180	tp->tun_flags &= ~TUN_OPEN;
181
182	/*
183	 * junk all pending output
184	 */
185	do {
186		s = splimp();
187		IF_DEQUEUE(&ifp->if_snd, m);
188		splx(s);
189		if (m)
190			m_freem(m);
191	} while (m);
192
193	if (ifp->if_flags & IFF_UP) {
194		s = splimp();
195		if_down(ifp);
196		if (ifp->if_flags & IFF_RUNNING) {
197		    /* find internet addresses and delete routes */
198		    register struct ifaddr *ifa;
199		    for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
200			if (ifa->ifa_addr->sa_family == AF_INET) {
201			    rtinit(ifa, (int)RTM_DELETE,
202				   tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
203			}
204		    }
205		}
206		splx(s);
207	}
208	tp->tun_pgrp = 0;
209	selwakeup(&tp->tun_rsel);
210
211	TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit);
212	return (0);
213}
214
215static int
216tuninit(unit)
217	int	unit;
218{
219	struct tun_softc *tp = &tunctl[unit];
220	struct ifnet	*ifp = &tp->tun_if;
221	register struct ifaddr *ifa;
222
223	TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit);
224
225	ifp->if_flags |= IFF_UP | IFF_RUNNING;
226
227	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
228		if (ifa->ifa_addr->sa_family == AF_INET) {
229		    struct sockaddr_in *si;
230
231		    si = (struct sockaddr_in *)ifa->ifa_addr;
232		    if (si && si->sin_addr.s_addr)
233			    tp->tun_flags |= TUN_IASET;
234
235		    si = (struct sockaddr_in *)ifa->ifa_dstaddr;
236		    if (si && si->sin_addr.s_addr)
237			    tp->tun_flags |= TUN_DSTADDR;
238		}
239
240	return 0;
241}
242
243/*
244 * Process an ioctl request.
245 */
246int
247tunifioctl(ifp, cmd, data)
248	struct ifnet *ifp;
249	int	cmd;
250	caddr_t	data;
251{
252	register struct ifreq *ifr = (struct ifreq *)data;
253	int		error = 0, s;
254
255	s = splimp();
256	switch(cmd) {
257	case SIOCSIFADDR:
258		tuninit(ifp->if_unit);
259		TUNDEBUG("%s%d: address set\n",
260			 ifp->if_name, ifp->if_unit);
261		break;
262	case SIOCSIFDSTADDR:
263		tuninit(ifp->if_unit);
264		TUNDEBUG("%s%d: destination address set\n",
265			 ifp->if_name, ifp->if_unit);
266		break;
267	case SIOCADDMULTI:
268	case SIOCDELMULTI:
269		if (ifr == 0) {
270			error = EAFNOSUPPORT;		/* XXX */
271			break;
272		}
273		switch (ifr->ifr_addr.sa_family) {
274
275#ifdef INET
276		case AF_INET:
277			break;
278#endif
279
280		default:
281			error = EAFNOSUPPORT;
282			break;
283		}
284		break;
285
286
287	default:
288		error = EINVAL;
289	}
290	splx(s);
291	return (error);
292}
293
294/*
295 * tunoutput - queue packets from higher level ready to put out.
296 */
297int
298tunoutput(ifp, m0, dst, rt)
299	struct ifnet   *ifp;
300	struct mbuf    *m0;
301	struct sockaddr *dst;
302	struct rtentry *rt;
303{
304	struct tun_softc *tp = &tunctl[ifp->if_unit];
305	struct proc	*p;
306	int		s;
307
308	TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit);
309
310	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
311		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
312			  ifp->if_unit, tp->tun_flags);
313		m_freem (m0);
314		return EHOSTDOWN;
315	}
316
317#if NBPFILTER > 0
318	/* BPF write needs to be handled specially */
319	if (dst->sa_family == AF_UNSPEC) {
320		dst->sa_family = *(mtod(m0, int *));
321		m0->m_len -= sizeof(int);
322		m0->m_pkthdr.len -= sizeof(int);
323		m0->m_data += sizeof(int);
324	}
325
326	if (ifp->if_bpf) {
327		/*
328		 * We need to prepend the address family as
329		 * a four byte field.  Cons up a dummy header
330		 * to pacify bpf.  This is safe because bpf
331		 * will only read from the mbuf (i.e., it won't
332		 * try to free it or keep a pointer to it).
333		 */
334		struct mbuf m;
335		u_int af = dst->sa_family;
336
337		m.m_next = m0;
338		m.m_len = 4;
339		m.m_data = (char *)&af;
340
341		bpf_mtap(ifp, &m);
342	}
343#endif
344
345	switch(dst->sa_family) {
346#ifdef INET
347	case AF_INET:
348		s = splimp();
349		if (IF_QFULL(&ifp->if_snd)) {
350			IF_DROP(&ifp->if_snd);
351			m_freem(m0);
352			splx(s);
353			ifp->if_collisions++;
354			return (ENOBUFS);
355		}
356		IF_ENQUEUE(&ifp->if_snd, m0);
357		splx(s);
358		ifp->if_opackets++;
359		break;
360#endif
361	default:
362		m_freem(m0);
363		return EAFNOSUPPORT;
364	}
365
366	if (tp->tun_flags & TUN_RWAIT) {
367		tp->tun_flags &= ~TUN_RWAIT;
368		wakeup((caddr_t)tp);
369	}
370	if (tp->tun_flags & TUN_ASYNC && tp->tun_pgrp) {
371		if (tp->tun_pgrp > 0)
372			gsignal(tp->tun_pgrp, SIGIO);
373		else if ((p = pfind(-tp->tun_pgrp)) != 0)
374			psignal(p, SIGIO);
375	}
376	selwakeup(&tp->tun_rsel);
377	return 0;
378}
379
380/*
381 * the cdevsw interface is now pretty minimal.
382 */
383static	int
384tunioctl(dev, cmd, data, flag, p)
385	dev_t		dev;
386	int		cmd;
387	caddr_t		data;
388	int		flag;
389	struct proc	*p;
390{
391	int		unit = minor(dev), s;
392	struct tun_softc *tp = &tunctl[unit];
393 	struct tuninfo *tunp;
394
395	switch (cmd) {
396 	case TUNSIFINFO:
397 	        tunp = (struct tuninfo *)data;
398 		tp->tun_if.if_mtu = tunp->mtu;
399 		tp->tun_if.if_type = tunp->type;
400 		tp->tun_if.if_baudrate = tunp->baudrate;
401 		break;
402 	case TUNGIFINFO:
403 		tunp = (struct tuninfo *)data;
404 		tunp->mtu = tp->tun_if.if_mtu;
405 		tunp->type = tp->tun_if.if_type;
406 		tunp->baudrate = tp->tun_if.if_baudrate;
407 		break;
408	case TUNSDEBUG:
409		tundebug = *(int *)data;
410		break;
411	case TUNGDEBUG:
412		*(int *)data = tundebug;
413		break;
414	case FIONBIO:
415		if (*(int *)data)
416			tp->tun_flags |= TUN_NBIO;
417		else
418			tp->tun_flags &= ~TUN_NBIO;
419		break;
420	case FIOASYNC:
421		if (*(int *)data)
422			tp->tun_flags |= TUN_ASYNC;
423		else
424			tp->tun_flags &= ~TUN_ASYNC;
425		break;
426	case FIONREAD:
427		s = splimp();
428		if (tp->tun_if.if_snd.ifq_head) {
429			struct mbuf *mb = tp->tun_if.if_snd.ifq_head;
430			for( *(int *)data = 0; mb != 0; mb = mb->m_next)
431				*(int *)data += mb->m_len;
432		} else
433			*(int *)data = 0;
434		splx(s);
435		break;
436	case TIOCSPGRP:
437		tp->tun_pgrp = *(int *)data;
438		break;
439	case TIOCGPGRP:
440		*(int *)data = tp->tun_pgrp;
441		break;
442	default:
443		return (ENOTTY);
444	}
445	return (0);
446}
447
448/*
449 * The cdevsw read interface - reads a packet at a time, or at
450 * least as much of a packet as can be read.
451 */
452static	int
453tunread(dev_t dev, struct uio *uio, int flag)
454{
455	int		unit = minor(dev);
456	struct tun_softc *tp = &tunctl[unit];
457	struct ifnet	*ifp = &tp->tun_if;
458	struct mbuf	*m, *m0;
459	int		error=0, len, s;
460
461	TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit);
462	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
463		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
464			  ifp->if_unit, tp->tun_flags);
465		return EHOSTDOWN;
466	}
467
468	tp->tun_flags &= ~TUN_RWAIT;
469
470	s = splimp();
471	do {
472		IF_DEQUEUE(&ifp->if_snd, m0);
473		if (m0 == 0) {
474			if (tp->tun_flags & TUN_NBIO) {
475				splx(s);
476				return EWOULDBLOCK;
477			}
478			tp->tun_flags |= TUN_RWAIT;
479			tsleep((caddr_t)tp, PZERO + 1, "tunread", 0);
480		}
481	} while (m0 == 0);
482	splx(s);
483
484	while (m0 && uio->uio_resid > 0 && error == 0) {
485		len = min(uio->uio_resid, m0->m_len);
486		if (len == 0)
487			break;
488		error = uiomove(mtod(m0, caddr_t), len, uio);
489		MFREE(m0, m);
490		m0 = m;
491	}
492
493	if (m0) {
494		TUNDEBUG("Dropping mbuf\n");
495		m_freem(m0);
496	}
497	return error;
498}
499
500/*
501 * the cdevsw write interface - an atomic write is a packet - or else!
502 */
503static	int
504tunwrite(dev_t dev, struct uio *uio, int flag)
505{
506	int		unit = minor (dev);
507	struct ifnet	*ifp = &tunctl[unit].tun_if;
508	struct mbuf	*top, **mp, *m;
509	int		error=0, s, tlen, mlen;
510
511	TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
512
513	if (uio->uio_resid < 0 || uio->uio_resid > TUNMTU) {
514		TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit,
515		    uio->uio_resid);
516		return EIO;
517	}
518	tlen = uio->uio_resid;
519
520	/* get a header mbuf */
521	MGETHDR(m, M_DONTWAIT, MT_DATA);
522	if (m == NULL)
523		return ENOBUFS;
524	mlen = MHLEN;
525
526	top = 0;
527	mp = &top;
528	while (error == 0 && uio->uio_resid > 0) {
529		m->m_len = min(mlen, uio->uio_resid);
530		error = uiomove(mtod (m, caddr_t), m->m_len, uio);
531		*mp = m;
532		mp = &m->m_next;
533		if (uio->uio_resid > 0) {
534			MGET (m, M_DONTWAIT, MT_DATA);
535			if (m == 0) {
536				error = ENOBUFS;
537				break;
538			}
539			mlen = MLEN;
540		}
541	}
542	if (error) {
543		if (top)
544			m_freem (top);
545		return error;
546	}
547
548	top->m_pkthdr.len = tlen;
549	top->m_pkthdr.rcvif = ifp;
550
551#if NBPFILTER > 0
552	if (ifp->if_bpf) {
553		/*
554		 * We need to prepend the address family as
555		 * a four byte field.  Cons up a dummy header
556		 * to pacify bpf.  This is safe because bpf
557		 * will only read from the mbuf (i.e., it won't
558		 * try to free it or keep a pointer to it).
559		 */
560		struct mbuf m;
561		u_int af = AF_INET;
562
563		m.m_next = top;
564		m.m_len = 4;
565		m.m_data = (char *)&af;
566
567		bpf_mtap(ifp, &m);
568	}
569#endif
570
571	s = splimp();
572	if (IF_QFULL (&ipintrq)) {
573		IF_DROP(&ipintrq);
574		splx(s);
575		ifp->if_collisions++;
576		m_freem(top);
577		return ENOBUFS;
578	}
579	IF_ENQUEUE(&ipintrq, top);
580	splx(s);
581	ifp->if_ipackets++;
582	schednetisr(NETISR_IP);
583	return error;
584}
585
586/*
587 * tunselect - the select interface, this is only useful on reads
588 * really. The write detect always returns true, write never blocks
589 * anyway, it either accepts the packet or drops it.
590 */
591static	int
592tunselect(dev_t dev, int rw, struct proc *p)
593{
594	int		unit = minor(dev), s;
595	struct tun_softc *tp = &tunctl[unit];
596	struct ifnet	*ifp = &tp->tun_if;
597
598	s = splimp();
599	TUNDEBUG("%s%d: tunselect\n", ifp->if_name, ifp->if_unit);
600
601	switch (rw) {
602	case FREAD:
603		if (ifp->if_snd.ifq_len > 0) {
604			splx(s);
605			TUNDEBUG("%s%d: tunselect q=%d\n", ifp->if_name,
606			    ifp->if_unit, ifp->if_snd.ifq_len);
607			return 1;
608		}
609		selrecord(p, &tp->tun_rsel);
610		break;
611	case FWRITE:
612		splx(s);
613		return 1;
614	}
615	splx(s);
616	TUNDEBUG("%s%d: tunselect waiting\n", ifp->if_name, ifp->if_unit);
617	return 0;
618}
619
620
621#endif  /* NTUN */
622