if_tun.c revision 16332 
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 )
108		return;
109	dev = makedev(CDEV_MAJOR, 0);
110	cdevsw_add(&dev, &tun_cdevsw, NULL);
111	tun_devsw_installed = 1;
112	for ( i = 0; i < NTUN; i++ ) {
113#ifdef DEVFS
114		tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, i, DV_CHR,
115						      UID_UUCP, GID_DIALER,
116						      0600, "tun%d", i);
117#endif
118		tunctl[i].tun_flags = TUN_INITED;
119
120		ifp = &tunctl[i].tun_if;
121		ifp->if_unit = i;
122		ifp->if_name = "tun";
123		ifp->if_mtu = TUNMTU;
124		ifp->if_ioctl = tunifioctl;
125		ifp->if_output = tunoutput;
126		ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
127		ifp->if_snd.ifq_maxlen = ifqmaxlen;
128		ifp->if_collisions = 0;
129		ifp->if_ierrors = 0;
130		ifp->if_oerrors = 0;
131		ifp->if_ipackets = 0;
132		ifp->if_opackets = 0;
133		if_attach(ifp);
134#if NBPFILTER > 0
135		bpfattach(ifp, DLT_NULL, sizeof(u_int));
136#endif
137	}
138}
139
140/*
141 * tunnel open - must be superuser & the device must be
142 * configured in
143 */
144static	int
145tunopen(dev, flag, mode, p)
146	dev_t	dev;
147	int	flag, mode;
148	struct proc *p;
149{
150	struct ifnet	*ifp;
151	struct tun_softc *tp;
152	register int	unit, error;
153
154	error = suser(p->p_ucred, &p->p_acflag);
155	if (error)
156		return (error);
157
158	if ((unit = minor(dev)) >= NTUN)
159		return (ENXIO);
160	tp = &tunctl[unit];
161	if (tp->tun_flags & TUN_OPEN)
162		return EBUSY;
163	ifp = &tp->tun_if;
164	tp->tun_flags |= TUN_OPEN;
165	TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit);
166	return (0);
167}
168
169/*
170 * tunclose - close the device - mark i/f down & delete
171 * routing info
172 */
173static	int
174tunclose(dev_t dev, int foo, int bar, struct proc *p)
175{
176	register int	unit = minor(dev), s;
177	struct tun_softc *tp = &tunctl[unit];
178	struct ifnet	*ifp = &tp->tun_if;
179	struct mbuf	*m;
180
181	tp->tun_flags &= ~TUN_OPEN;
182
183	/*
184	 * junk all pending output
185	 */
186	do {
187		s = splimp();
188		IF_DEQUEUE(&ifp->if_snd, m);
189		splx(s);
190		if (m)
191			m_freem(m);
192	} while (m);
193
194	if (ifp->if_flags & IFF_UP) {
195		s = splimp();
196		if_down(ifp);
197		microtime(&ifp->if_lastchange);
198		if (ifp->if_flags & IFF_RUNNING) {
199		    /* find internet addresses and delete routes */
200		    register struct ifaddr *ifa;
201		    for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
202			if (ifa->ifa_addr->sa_family == AF_INET) {
203			    rtinit(ifa, (int)RTM_DELETE,
204				   tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
205			}
206		    }
207		}
208		splx(s);
209	}
210	tp->tun_pgrp = 0;
211	selwakeup(&tp->tun_rsel);
212
213	TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit);
214	return (0);
215}
216
217static int
218tuninit(unit)
219	int	unit;
220{
221	struct tun_softc *tp = &tunctl[unit];
222	struct ifnet	*ifp = &tp->tun_if;
223	register struct ifaddr *ifa;
224
225	TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit);
226
227	ifp->if_flags |= IFF_UP | IFF_RUNNING;
228	microtime(&ifp->if_lastchange);
229
230	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
231		if (ifa->ifa_addr->sa_family == AF_INET) {
232		    struct sockaddr_in *si;
233
234		    si = (struct sockaddr_in *)ifa->ifa_addr;
235		    if (si && si->sin_addr.s_addr)
236			    tp->tun_flags |= TUN_IASET;
237
238		    si = (struct sockaddr_in *)ifa->ifa_dstaddr;
239		    if (si && si->sin_addr.s_addr)
240			    tp->tun_flags |= TUN_DSTADDR;
241		}
242
243	return 0;
244}
245
246/*
247 * Process an ioctl request.
248 */
249int
250tunifioctl(ifp, cmd, data)
251	struct ifnet *ifp;
252	int	cmd;
253	caddr_t	data;
254{
255	register struct ifreq *ifr = (struct ifreq *)data;
256	int		error = 0, s;
257
258	s = splimp();
259	switch(cmd) {
260	case SIOCSIFADDR:
261		tuninit(ifp->if_unit);
262		TUNDEBUG("%s%d: address set\n",
263			 ifp->if_name, ifp->if_unit);
264		break;
265	case SIOCSIFDSTADDR:
266		tuninit(ifp->if_unit);
267		TUNDEBUG("%s%d: destination address set\n",
268			 ifp->if_name, ifp->if_unit);
269		break;
270	case SIOCADDMULTI:
271	case SIOCDELMULTI:
272		if (ifr == 0) {
273			error = EAFNOSUPPORT;		/* XXX */
274			break;
275		}
276		switch (ifr->ifr_addr.sa_family) {
277
278#ifdef INET
279		case AF_INET:
280			break;
281#endif
282
283		default:
284			error = EAFNOSUPPORT;
285			break;
286		}
287		break;
288
289
290	default:
291		error = EINVAL;
292	}
293	splx(s);
294	return (error);
295}
296
297/*
298 * tunoutput - queue packets from higher level ready to put out.
299 */
300int
301tunoutput(ifp, m0, dst, rt)
302	struct ifnet   *ifp;
303	struct mbuf    *m0;
304	struct sockaddr *dst;
305	struct rtentry *rt;
306{
307	struct tun_softc *tp = &tunctl[ifp->if_unit];
308	struct proc	*p;
309	int		s;
310
311	TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit);
312
313	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
314		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
315			  ifp->if_unit, tp->tun_flags);
316		m_freem (m0);
317		return EHOSTDOWN;
318	}
319
320#if NBPFILTER > 0
321	/* BPF write needs to be handled specially */
322	if (dst->sa_family == AF_UNSPEC) {
323		dst->sa_family = *(mtod(m0, int *));
324		m0->m_len -= sizeof(int);
325		m0->m_pkthdr.len -= sizeof(int);
326		m0->m_data += sizeof(int);
327	}
328
329	if (ifp->if_bpf) {
330		/*
331		 * We need to prepend the address family as
332		 * a four byte field.  Cons up a dummy header
333		 * to pacify bpf.  This is safe because bpf
334		 * will only read from the mbuf (i.e., it won't
335		 * try to free it or keep a pointer to it).
336		 */
337		struct mbuf m;
338		u_int af = dst->sa_family;
339
340		m.m_next = m0;
341		m.m_len = 4;
342		m.m_data = (char *)&af;
343
344		bpf_mtap(ifp, &m);
345	}
346#endif
347
348	switch(dst->sa_family) {
349#ifdef INET
350	case AF_INET:
351		s = splimp();
352		if (IF_QFULL(&ifp->if_snd)) {
353			IF_DROP(&ifp->if_snd);
354			m_freem(m0);
355			splx(s);
356			ifp->if_collisions++;
357			return (ENOBUFS);
358		}
359		ifp->if_obytes += m0->m_pkthdr.len;
360		IF_ENQUEUE(&ifp->if_snd, m0);
361		splx(s);
362		ifp->if_opackets++;
363		break;
364#endif
365	default:
366		m_freem(m0);
367		return EAFNOSUPPORT;
368	}
369
370	if (tp->tun_flags & TUN_RWAIT) {
371		tp->tun_flags &= ~TUN_RWAIT;
372		wakeup((caddr_t)tp);
373	}
374	if (tp->tun_flags & TUN_ASYNC && tp->tun_pgrp) {
375		if (tp->tun_pgrp > 0)
376			gsignal(tp->tun_pgrp, SIGIO);
377		else if ((p = pfind(-tp->tun_pgrp)) != 0)
378			psignal(p, SIGIO);
379	}
380	selwakeup(&tp->tun_rsel);
381	return 0;
382}
383
384/*
385 * the cdevsw interface is now pretty minimal.
386 */
387static	int
388tunioctl(dev, cmd, data, flag, p)
389	dev_t		dev;
390	int		cmd;
391	caddr_t		data;
392	int		flag;
393	struct proc	*p;
394{
395	int		unit = minor(dev), s;
396	struct tun_softc *tp = &tunctl[unit];
397 	struct tuninfo *tunp;
398
399	switch (cmd) {
400 	case TUNSIFINFO:
401 	        tunp = (struct tuninfo *)data;
402 		tp->tun_if.if_mtu = tunp->mtu;
403 		tp->tun_if.if_type = tunp->type;
404 		tp->tun_if.if_baudrate = tunp->baudrate;
405 		break;
406 	case TUNGIFINFO:
407 		tunp = (struct tuninfo *)data;
408 		tunp->mtu = tp->tun_if.if_mtu;
409 		tunp->type = tp->tun_if.if_type;
410 		tunp->baudrate = tp->tun_if.if_baudrate;
411 		break;
412	case TUNSDEBUG:
413		tundebug = *(int *)data;
414		break;
415	case TUNGDEBUG:
416		*(int *)data = tundebug;
417		break;
418	case FIONBIO:
419		if (*(int *)data)
420			tp->tun_flags |= TUN_NBIO;
421		else
422			tp->tun_flags &= ~TUN_NBIO;
423		break;
424	case FIOASYNC:
425		if (*(int *)data)
426			tp->tun_flags |= TUN_ASYNC;
427		else
428			tp->tun_flags &= ~TUN_ASYNC;
429		break;
430	case FIONREAD:
431		s = splimp();
432		if (tp->tun_if.if_snd.ifq_head) {
433			struct mbuf *mb = tp->tun_if.if_snd.ifq_head;
434			for( *(int *)data = 0; mb != 0; mb = mb->m_next)
435				*(int *)data += mb->m_len;
436		} else
437			*(int *)data = 0;
438		splx(s);
439		break;
440	case TIOCSPGRP:
441		tp->tun_pgrp = *(int *)data;
442		break;
443	case TIOCGPGRP:
444		*(int *)data = tp->tun_pgrp;
445		break;
446	default:
447		return (ENOTTY);
448	}
449	return (0);
450}
451
452/*
453 * The cdevsw read interface - reads a packet at a time, or at
454 * least as much of a packet as can be read.
455 */
456static	int
457tunread(dev_t dev, struct uio *uio, int flag)
458{
459	int		unit = minor(dev);
460	struct tun_softc *tp = &tunctl[unit];
461	struct ifnet	*ifp = &tp->tun_if;
462	struct mbuf	*m, *m0;
463	int		error=0, len, s;
464
465	TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit);
466	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
467		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
468			  ifp->if_unit, tp->tun_flags);
469		return EHOSTDOWN;
470	}
471
472	tp->tun_flags &= ~TUN_RWAIT;
473
474	s = splimp();
475	do {
476		IF_DEQUEUE(&ifp->if_snd, m0);
477		if (m0 == 0) {
478			if (tp->tun_flags & TUN_NBIO) {
479				splx(s);
480				return EWOULDBLOCK;
481			}
482			tp->tun_flags |= TUN_RWAIT;
483			tsleep((caddr_t)tp, PZERO + 1, "tunread", 0);
484		}
485	} while (m0 == 0);
486	splx(s);
487
488	while (m0 && uio->uio_resid > 0 && error == 0) {
489		len = min(uio->uio_resid, m0->m_len);
490		if (len == 0)
491			break;
492		error = uiomove(mtod(m0, caddr_t), len, uio);
493		MFREE(m0, m);
494		m0 = m;
495	}
496
497	if (m0) {
498		TUNDEBUG("Dropping mbuf\n");
499		m_freem(m0);
500	}
501	return error;
502}
503
504/*
505 * the cdevsw write interface - an atomic write is a packet - or else!
506 */
507static	int
508tunwrite(dev_t dev, struct uio *uio, int flag)
509{
510	int		unit = minor (dev);
511	struct ifnet	*ifp = &tunctl[unit].tun_if;
512	struct mbuf	*top, **mp, *m;
513	int		error=0, s, tlen, mlen;
514
515	TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
516
517	if (uio->uio_resid < 0 || uio->uio_resid > TUNMTU) {
518		TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit,
519		    uio->uio_resid);
520		return EIO;
521	}
522	tlen = uio->uio_resid;
523
524	/* get a header mbuf */
525	MGETHDR(m, M_DONTWAIT, MT_DATA);
526	if (m == NULL)
527		return ENOBUFS;
528	mlen = MHLEN;
529
530	top = 0;
531	mp = &top;
532	while (error == 0 && uio->uio_resid > 0) {
533		m->m_len = min(mlen, uio->uio_resid);
534		error = uiomove(mtod (m, caddr_t), m->m_len, uio);
535		*mp = m;
536		mp = &m->m_next;
537		if (uio->uio_resid > 0) {
538			MGET (m, M_DONTWAIT, MT_DATA);
539			if (m == 0) {
540				error = ENOBUFS;
541				break;
542			}
543			mlen = MLEN;
544		}
545	}
546	if (error) {
547		if (top)
548			m_freem (top);
549		return error;
550	}
551
552	top->m_pkthdr.len = tlen;
553	top->m_pkthdr.rcvif = ifp;
554
555#if NBPFILTER > 0
556	if (ifp->if_bpf) {
557		/*
558		 * We need to prepend the address family as
559		 * a four byte field.  Cons up a dummy header
560		 * to pacify bpf.  This is safe because bpf
561		 * will only read from the mbuf (i.e., it won't
562		 * try to free it or keep a pointer to it).
563		 */
564		struct mbuf m;
565		u_int af = AF_INET;
566
567		m.m_next = top;
568		m.m_len = 4;
569		m.m_data = (char *)&af;
570
571		bpf_mtap(ifp, &m);
572	}
573#endif
574
575	s = splimp();
576	if (IF_QFULL (&ipintrq)) {
577		IF_DROP(&ipintrq);
578		splx(s);
579		ifp->if_collisions++;
580		m_freem(top);
581		return ENOBUFS;
582	}
583	IF_ENQUEUE(&ipintrq, top);
584	splx(s);
585	ifp->if_ibytes += tlen;
586	ifp->if_ipackets++;
587	schednetisr(NETISR_IP);
588	return error;
589}
590
591/*
592 * tunselect - the select interface, this is only useful on reads
593 * really. The write detect always returns true, write never blocks
594 * anyway, it either accepts the packet or drops it.
595 */
596static	int
597tunselect(dev_t dev, int rw, struct proc *p)
598{
599	int		unit = minor(dev), s;
600	struct tun_softc *tp = &tunctl[unit];
601	struct ifnet	*ifp = &tp->tun_if;
602
603	s = splimp();
604	TUNDEBUG("%s%d: tunselect\n", ifp->if_name, ifp->if_unit);
605
606	switch (rw) {
607	case FREAD:
608		if (ifp->if_snd.ifq_len > 0) {
609			splx(s);
610			TUNDEBUG("%s%d: tunselect q=%d\n", ifp->if_name,
611			    ifp->if_unit, ifp->if_snd.ifq_len);
612			return 1;
613		}
614		selrecord(p, &tp->tun_rsel);
615		break;
616	case FWRITE:
617		splx(s);
618		return 1;
619	}
620	splx(s);
621	TUNDEBUG("%s%d: tunselect waiting\n", ifp->if_name, ifp->if_unit);
622	return 0;
623}
624
625
626#endif  /* NTUN */
627