if_tun.c revision 46112 
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 its 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/poll mode of
14 * operation though.
15 */
16
17#include "tun.h"
18#if NTUN > 0
19
20#include "opt_devfs.h"
21#include "opt_inet.h"
22
23#include <sys/param.h>
24#include <sys/proc.h>
25#include <sys/systm.h>
26#include <sys/mbuf.h>
27#include <sys/socket.h>
28#include <sys/filio.h>
29#include <sys/sockio.h>
30#include <sys/ttycom.h>
31#include <sys/poll.h>
32#include <sys/signalvar.h>
33#include <sys/filedesc.h>
34#include <sys/kernel.h>
35#include <sys/sysctl.h>
36#ifdef DEVFS
37#include <sys/devfsext.h>
38#endif /*DEVFS*/
39#include <sys/conf.h>
40#include <sys/uio.h>
41#include <sys/vnode.h>
42
43#include <net/if.h>
44#include <net/netisr.h>
45#include <net/route.h>
46
47#ifdef INET
48#include <netinet/in.h>
49#include <netinet/in_var.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 <net/bpf.h>
60#endif
61
62#include <net/if_tunvar.h>
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 *, u_long, 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_poll_t	tunpoll;
85
86#define CDEV_MAJOR 52
87static struct cdevsw tun_cdevsw = {
88	tunopen,	tunclose,	tunread,	tunwrite,
89	tunioctl,	nullstop,	noreset,	nodevtotty,
90	tunpoll,	nommap,		nostrategy,	"tun",	NULL,	-1
91};
92
93
94static	int	tun_devsw_installed;
95#ifdef	DEVFS
96static	void	*tun_devfs_token[NTUN];
97#endif
98
99#define minor_val(n) ((((n) & ~0xff) << 8) | ((n) & 0xff))
100#define dev_val(n) (((n) >> 8) | ((n) & 0xff))
101
102static void
103tunattach(dummy)
104	void *dummy;
105{
106	register int i;
107	struct ifnet *ifp;
108	dev_t dev;
109
110	if ( tun_devsw_installed )
111		return;
112	dev = makedev(CDEV_MAJOR, 0);
113	cdevsw_add(&dev, &tun_cdevsw, NULL);
114	tun_devsw_installed = 1;
115	for ( i = 0; i < NTUN; i++ ) {
116#ifdef DEVFS
117		tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, minor_val(i),
118						      DV_CHR, UID_UUCP,
119						      GID_DIALER, 0600,
120						      "tun%d", i);
121#endif
122		tunctl[i].tun_flags = TUN_INITED;
123
124		ifp = &tunctl[i].tun_if;
125		ifp->if_unit = i;
126		ifp->if_name = "tun";
127		ifp->if_mtu = TUNMTU;
128		ifp->if_ioctl = tunifioctl;
129		ifp->if_output = tunoutput;
130		ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
131		ifp->if_snd.ifq_maxlen = ifqmaxlen;
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);
154	if (error)
155		return (error);
156
157	if ((unit = dev_val(minor(dev))) >= NTUN)
158		return (ENXIO);
159	tp = &tunctl[unit];
160	if (tp->tun_flags & TUN_OPEN)
161		return EBUSY;
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, foo, bar, p)
174	dev_t dev;
175	int foo;
176	int bar;
177	struct proc *p;
178{
179	register int	unit = dev_val(minor(dev)), s;
180	struct tun_softc *tp = &tunctl[unit];
181	struct ifnet	*ifp = &tp->tun_if;
182	struct mbuf	*m;
183
184	tp->tun_flags &= ~TUN_OPEN;
185
186	/*
187	 * junk all pending output
188	 */
189	do {
190		s = splimp();
191		IF_DEQUEUE(&ifp->if_snd, m);
192		splx(s);
193		if (m)
194			m_freem(m);
195	} while (m);
196
197	if (ifp->if_flags & IFF_UP) {
198		s = splimp();
199		if_down(ifp);
200		if (ifp->if_flags & IFF_RUNNING) {
201		    /* find internet addresses and delete routes */
202		    register struct ifaddr *ifa;
203		    for (ifa = ifp->if_addrhead.tqh_first; ifa;
204			 ifa = ifa->ifa_link.tqe_next) {
205			if (ifa->ifa_addr->sa_family == AF_INET) {
206			    rtinit(ifa, (int)RTM_DELETE,
207				   tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
208			}
209		    }
210		}
211		splx(s);
212	}
213	funsetown(tp->tun_sigio);
214	selwakeup(&tp->tun_rsel);
215
216	TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit);
217	return (0);
218}
219
220static int
221tuninit(unit)
222	int	unit;
223{
224	struct tun_softc *tp = &tunctl[unit];
225	struct ifnet	*ifp = &tp->tun_if;
226	register struct ifaddr *ifa;
227
228	TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit);
229
230	ifp->if_flags |= IFF_UP | IFF_RUNNING;
231	getmicrotime(&ifp->if_lastchange);
232
233	for (ifa = ifp->if_addrhead.tqh_first; ifa;
234	     ifa = ifa->ifa_link.tqe_next) {
235#ifdef INET
236		if (ifa->ifa_addr->sa_family == AF_INET) {
237		    struct sockaddr_in *si;
238
239		    si = (struct sockaddr_in *)ifa->ifa_addr;
240		    if (si && si->sin_addr.s_addr)
241			    tp->tun_flags |= TUN_IASET;
242
243		    si = (struct sockaddr_in *)ifa->ifa_dstaddr;
244		    if (si && si->sin_addr.s_addr)
245			    tp->tun_flags |= TUN_DSTADDR;
246		}
247#endif
248	}
249	return 0;
250}
251
252/*
253 * Process an ioctl request.
254 */
255int
256tunifioctl(ifp, cmd, data)
257	struct ifnet *ifp;
258	u_long	cmd;
259	caddr_t	data;
260{
261	register struct ifreq *ifr = (struct ifreq *)data;
262	int		error = 0, s;
263
264	s = splimp();
265	switch(cmd) {
266	case SIOCSIFADDR:
267		tuninit(ifp->if_unit);
268		TUNDEBUG("%s%d: address set\n",
269			 ifp->if_name, ifp->if_unit);
270		break;
271	case SIOCSIFDSTADDR:
272		tuninit(ifp->if_unit);
273		TUNDEBUG("%s%d: destination address set\n",
274			 ifp->if_name, ifp->if_unit);
275		break;
276	case SIOCSIFMTU:
277		ifp->if_mtu = ifr->ifr_mtu;
278		TUNDEBUG("%s%d: mtu set\n",
279			 ifp->if_name, ifp->if_unit);
280		break;
281	case SIOCADDMULTI:
282	case SIOCDELMULTI:
283		break;
284
285
286	default:
287		error = EINVAL;
288	}
289	splx(s);
290	return (error);
291}
292
293/*
294 * tunoutput - queue packets from higher level ready to put out.
295 */
296int
297tunoutput(ifp, m0, dst, rt)
298	struct ifnet   *ifp;
299	struct mbuf    *m0;
300	struct sockaddr *dst;
301	struct rtentry *rt;
302{
303	struct tun_softc *tp = &tunctl[ifp->if_unit];
304	int		s;
305
306	TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit);
307
308	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
309		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
310			  ifp->if_unit, tp->tun_flags);
311		m_freem (m0);
312		return EHOSTDOWN;
313	}
314
315#if NBPFILTER > 0
316	/* BPF write needs to be handled specially */
317	if (dst->sa_family == AF_UNSPEC) {
318		dst->sa_family = *(mtod(m0, int *));
319		m0->m_len -= sizeof(int);
320		m0->m_pkthdr.len -= sizeof(int);
321		m0->m_data += sizeof(int);
322	}
323
324	if (ifp->if_bpf) {
325		/*
326		 * We need to prepend the address family as
327		 * a four byte field.  Cons up a dummy header
328		 * to pacify bpf.  This is safe because bpf
329		 * will only read from the mbuf (i.e., it won't
330		 * try to free it or keep a pointer to it).
331		 */
332		struct mbuf m;
333		u_int af = dst->sa_family;
334
335		m.m_next = m0;
336		m.m_len = 4;
337		m.m_data = (char *)&af;
338
339		bpf_mtap(ifp, &m);
340	}
341#endif /* NBPFILTER > 0 */
342
343	/* prepend sockaddr? this may abort if the mbuf allocation fails */
344	if (tp->tun_flags & TUN_LMODE) {
345		/* allocate space for sockaddr */
346		M_PREPEND(m0, dst->sa_len, M_DONTWAIT);
347
348		/* if allocation failed drop packet */
349		if (m0 == NULL){
350			s = splimp();	/* spl on queue manipulation */
351			IF_DROP(&ifp->if_snd);
352			splx(s);
353			ifp->if_oerrors++;
354			return (ENOBUFS);
355		} else {
356			bcopy(dst, m0->m_data, dst->sa_len);
357		}
358	}
359
360	switch(dst->sa_family) {
361#ifdef INET
362	case AF_INET:
363		s = splimp();
364		if (IF_QFULL(&ifp->if_snd)) {
365			IF_DROP(&ifp->if_snd);
366			m_freem(m0);
367			splx(s);
368			ifp->if_collisions++;
369			return (ENOBUFS);
370		}
371		ifp->if_obytes += m0->m_pkthdr.len;
372		IF_ENQUEUE(&ifp->if_snd, m0);
373		splx(s);
374		ifp->if_opackets++;
375		break;
376#endif
377	default:
378		m_freem(m0);
379		return EAFNOSUPPORT;
380	}
381
382	if (tp->tun_flags & TUN_RWAIT) {
383		tp->tun_flags &= ~TUN_RWAIT;
384		wakeup((caddr_t)tp);
385	}
386	if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
387		pgsigio(tp->tun_sigio, SIGIO, 0);
388	selwakeup(&tp->tun_rsel);
389	return 0;
390}
391
392/*
393 * the cdevsw interface is now pretty minimal.
394 */
395static	int
396tunioctl(dev, cmd, data, flag, p)
397	dev_t		dev;
398	u_long		cmd;
399	caddr_t		data;
400	int		flag;
401	struct proc	*p;
402{
403	int		unit = dev_val(minor(dev)), s;
404	struct tun_softc *tp = &tunctl[unit];
405 	struct tuninfo *tunp;
406
407	switch (cmd) {
408 	case TUNSIFINFO:
409 	        tunp = (struct tuninfo *)data;
410 		tp->tun_if.if_mtu = tunp->mtu;
411 		tp->tun_if.if_type = tunp->type;
412 		tp->tun_if.if_baudrate = tunp->baudrate;
413 		break;
414 	case TUNGIFINFO:
415 		tunp = (struct tuninfo *)data;
416 		tunp->mtu = tp->tun_if.if_mtu;
417 		tunp->type = tp->tun_if.if_type;
418 		tunp->baudrate = tp->tun_if.if_baudrate;
419 		break;
420	case TUNSDEBUG:
421		tundebug = *(int *)data;
422		break;
423	case TUNGDEBUG:
424		*(int *)data = tundebug;
425		break;
426	case TUNSLMODE:
427		if (*(int *)data)
428			tp->tun_flags |= TUN_LMODE;
429		else
430			tp->tun_flags &= ~TUN_LMODE;
431		break;
432	case TUNSIFMODE:
433		/* deny this if UP */
434		if (tp->tun_if.if_flags & IFF_UP)
435			return(EBUSY);
436
437		switch (*(int *)data) {
438		case IFF_POINTOPOINT:
439			tp->tun_if.if_flags |= IFF_POINTOPOINT;
440			tp->tun_if.if_flags &= ~IFF_BROADCAST;
441			break;
442		case IFF_BROADCAST:
443			tp->tun_if.if_flags &= ~IFF_POINTOPOINT;
444			tp->tun_if.if_flags |= IFF_BROADCAST;
445			break;
446		default:
447			return(EINVAL);
448		}
449		break;
450	case FIONBIO:
451		break;
452	case FIOASYNC:
453		if (*(int *)data)
454			tp->tun_flags |= TUN_ASYNC;
455		else
456			tp->tun_flags &= ~TUN_ASYNC;
457		break;
458	case FIONREAD:
459		s = splimp();
460		if (tp->tun_if.if_snd.ifq_head) {
461			struct mbuf *mb = tp->tun_if.if_snd.ifq_head;
462			for( *(int *)data = 0; mb != 0; mb = mb->m_next)
463				*(int *)data += mb->m_len;
464		} else
465			*(int *)data = 0;
466		splx(s);
467		break;
468	case FIOSETOWN:
469		return (fsetown(*(int *)data, &tp->tun_sigio));
470
471	case FIOGETOWN:
472		*(int *)data = fgetown(tp->tun_sigio);
473		return (0);
474
475	/* This is deprecated, FIOSETOWN should be used instead. */
476	case TIOCSPGRP:
477		return (fsetown(-(*(int *)data), &tp->tun_sigio));
478
479	/* This is deprecated, FIOGETOWN should be used instead. */
480	case TIOCGPGRP:
481		*(int *)data = -fgetown(tp->tun_sigio);
482		return (0);
483
484	default:
485		return (ENOTTY);
486	}
487	return (0);
488}
489
490/*
491 * The cdevsw read interface - reads a packet at a time, or at
492 * least as much of a packet as can be read.
493 */
494static	int
495tunread(dev, uio, flag)
496	dev_t dev;
497	struct uio *uio;
498	int flag;
499{
500	int		unit = dev_val(minor(dev));
501	struct tun_softc *tp = &tunctl[unit];
502	struct ifnet	*ifp = &tp->tun_if;
503	struct mbuf	*m, *m0;
504	int		error=0, len, s;
505
506	TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit);
507	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
508		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
509			  ifp->if_unit, tp->tun_flags);
510		return EHOSTDOWN;
511	}
512
513	tp->tun_flags &= ~TUN_RWAIT;
514
515	s = splimp();
516	do {
517		IF_DEQUEUE(&ifp->if_snd, m0);
518		if (m0 == 0) {
519			if (flag & IO_NDELAY) {
520				splx(s);
521				return EWOULDBLOCK;
522			}
523			tp->tun_flags |= TUN_RWAIT;
524			if((error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1),
525					"tunread", 0)) != 0) {
526				splx(s);
527				return error;
528			}
529		}
530	} while (m0 == 0);
531	splx(s);
532
533	while (m0 && uio->uio_resid > 0 && error == 0) {
534		len = min(uio->uio_resid, m0->m_len);
535		if (len == 0)
536			break;
537		error = uiomove(mtod(m0, caddr_t), len, uio);
538		MFREE(m0, m);
539		m0 = m;
540	}
541
542	if (m0) {
543		TUNDEBUG("Dropping mbuf\n");
544		m_freem(m0);
545	}
546	return error;
547}
548
549/*
550 * the cdevsw write interface - an atomic write is a packet - or else!
551 */
552static	int
553tunwrite(dev, uio, flag)
554	dev_t dev;
555	struct uio *uio;
556	int flag;
557{
558	int		unit = dev_val(minor(dev));
559	struct ifnet	*ifp = &tunctl[unit].tun_if;
560	struct mbuf	*top, **mp, *m;
561	int		error=0, s, tlen, mlen;
562
563	TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
564
565	if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) {
566		TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit,
567		    uio->uio_resid);
568		return EIO;
569	}
570	tlen = uio->uio_resid;
571
572	/* get a header mbuf */
573	MGETHDR(m, M_DONTWAIT, MT_DATA);
574	if (m == NULL)
575		return ENOBUFS;
576	mlen = MHLEN;
577
578	top = 0;
579	mp = &top;
580	while (error == 0 && uio->uio_resid > 0) {
581		m->m_len = min(mlen, uio->uio_resid);
582		error = uiomove(mtod (m, caddr_t), m->m_len, uio);
583		*mp = m;
584		mp = &m->m_next;
585		if (uio->uio_resid > 0) {
586			MGET (m, M_DONTWAIT, MT_DATA);
587			if (m == 0) {
588				error = ENOBUFS;
589				break;
590			}
591			mlen = MLEN;
592		}
593	}
594	if (error) {
595		if (top)
596			m_freem (top);
597		return error;
598	}
599
600	top->m_pkthdr.len = tlen;
601	top->m_pkthdr.rcvif = ifp;
602
603#if NBPFILTER > 0
604	if (ifp->if_bpf) {
605		/*
606		 * We need to prepend the address family as
607		 * a four byte field.  Cons up a dummy header
608		 * to pacify bpf.  This is safe because bpf
609		 * will only read from the mbuf (i.e., it won't
610		 * try to free it or keep a pointer to it).
611		 */
612		struct mbuf m;
613		u_int af = AF_INET;
614
615		m.m_next = top;
616		m.m_len = 4;
617		m.m_data = (char *)&af;
618
619		bpf_mtap(ifp, &m);
620	}
621#endif
622
623#ifdef INET
624	s = splimp();
625	if (IF_QFULL (&ipintrq)) {
626		IF_DROP(&ipintrq);
627		splx(s);
628		ifp->if_collisions++;
629		m_freem(top);
630		return ENOBUFS;
631	}
632	IF_ENQUEUE(&ipintrq, top);
633	splx(s);
634	ifp->if_ibytes += tlen;
635	ifp->if_ipackets++;
636	schednetisr(NETISR_IP);
637#endif
638	return error;
639}
640
641/*
642 * tunpoll - the poll interface, this is only useful on reads
643 * really. The write detect always returns true, write never blocks
644 * anyway, it either accepts the packet or drops it.
645 */
646static	int
647tunpoll(dev, events, p)
648	dev_t dev;
649	int events;
650	struct proc *p;
651{
652	int		unit = dev_val(minor(dev)), s;
653	struct tun_softc *tp = &tunctl[unit];
654	struct ifnet	*ifp = &tp->tun_if;
655	int		revents = 0;
656
657	s = splimp();
658	TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit);
659
660	if (events & (POLLIN | POLLRDNORM))
661		if (ifp->if_snd.ifq_len > 0) {
662			TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name,
663			    ifp->if_unit, ifp->if_snd.ifq_len);
664			revents |= events & (POLLIN | POLLRDNORM);
665		} else {
666			TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name,
667			    ifp->if_unit);
668			selrecord(p, &tp->tun_rsel);
669		}
670
671	if (events & (POLLOUT | POLLWRNORM))
672		revents |= events & (POLLOUT | POLLWRNORM);
673
674	splx(s);
675	return (revents);
676}
677
678
679#endif  /* NTUN */
680