if_tun.c revision 14852 
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 <machine/cpu.h>
41
42#include <net/if.h>
43#include <net/netisr.h>
44#include <net/route.h>
45
46#ifdef INET
47#include <netinet/in.h>
48#include <netinet/in_systm.h>
49#include <netinet/in_var.h>
50#include <netinet/ip.h>
51#include <netinet/if_ether.h>
52#endif
53
54#ifdef NS
55#include <netns/ns.h>
56#include <netns/ns_if.h>
57#endif
58
59#include "bpfilter.h"
60#if NBPFILTER > 0
61#include <sys/time.h>
62#include <net/bpf.h>
63#endif
64
65#include <net/if_tun.h>
66
67static void tunattach __P((void *));
68PSEUDO_SET(tunattach, if_tun);
69
70#define TUNDEBUG	if (tundebug) printf
71static int tundebug = 0;
72SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, "");
73
74static struct tun_softc tunctl[NTUN];
75
76static int tunoutput __P((struct ifnet *, struct mbuf *, struct sockaddr *,
77	    struct rtentry *rt));
78static int tunifioctl __P((struct ifnet *, int, caddr_t));
79static int tuninit __P((int));
80
81static	d_open_t	tunopen;
82static	d_close_t	tunclose;
83static	d_read_t	tunread;
84static	d_write_t	tunwrite;
85static	d_ioctl_t	tunioctl;
86static	d_select_t	tunselect;
87
88#define CDEV_MAJOR 52
89static struct cdevsw tun_cdevsw = {
90	tunopen,	tunclose,	tunread,	tunwrite,
91	tunioctl,	nullstop,	noreset,	nodevtotty,
92	tunselect,	nommap,		nostrategy,	"tun",	NULL,	-1
93};
94
95
96static tun_devsw_installed = 0;
97#ifdef	DEVFS
98static	void	*tun_devfs_token[NTUN];
99#endif
100
101static void
102tunattach(dummy)
103	void *dummy;
104{
105	register int i;
106	struct ifnet *ifp;
107	dev_t dev;
108
109	if( tun_devsw_installed ) return;
110	dev = makedev(CDEV_MAJOR, 0);
111	cdevsw_add(&dev,&tun_cdevsw, NULL);
112	tun_devsw_installed = 1;
113	for ( i = 0; i < NTUN; i++ ) {
114#ifdef DEVFS
115		tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, i, DV_CHR,
116						      UID_UUCP, GID_DIALER,
117						      0600, "tun%d", i);
118#endif
119		tunctl[i].tun_flags = TUN_INITED;
120
121		ifp = &tunctl[i].tun_if;
122		ifp->if_unit = i;
123		ifp->if_name = "tun";
124		ifp->if_mtu = TUNMTU;
125		ifp->if_ioctl = tunifioctl;
126		ifp->if_output = tunoutput;
127		ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
128		ifp->if_snd.ifq_maxlen = ifqmaxlen;
129		ifp->if_collisions = 0;
130		ifp->if_ierrors = 0;
131		ifp->if_oerrors = 0;
132		ifp->if_ipackets = 0;
133		ifp->if_opackets = 0;
134		if_attach(ifp);
135#if NBPFILTER > 0
136		bpfattach(ifp, DLT_NULL, sizeof(u_int));
137#endif
138	}
139}
140
141/*
142 * tunnel open - must be superuser & the device must be
143 * configured in
144 */
145static	int
146tunopen(dev, flag, mode, p)
147	dev_t	dev;
148	int	flag, mode;
149	struct proc *p;
150{
151	struct ifnet	*ifp;
152	struct tun_softc *tp;
153	register int	unit, error;
154
155	error = suser(p->p_ucred, &p->p_acflag);
156	if (error)
157		return (error);
158
159	if ((unit = minor(dev)) >= NTUN)
160		return (ENXIO);
161	tp = &tunctl[unit];
162	if (tp->tun_flags & TUN_OPEN)
163		return ENXIO;
164	ifp = &tp->tun_if;
165	tp->tun_flags |= TUN_OPEN;
166	TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit);
167	return (0);
168}
169
170/*
171 * tunclose - close the device - mark i/f down & delete
172 * routing info
173 */
174static	int
175tunclose(dev_t dev, int foo, int bar, struct proc *p)
176{
177	register int	unit = minor(dev), s;
178	struct tun_softc *tp = &tunctl[unit];
179	struct ifnet	*ifp = &tp->tun_if;
180	struct mbuf	*m;
181
182	tp->tun_flags &= ~TUN_OPEN;
183
184	/*
185	 * junk all pending output
186	 */
187	do {
188		s = splimp();
189		IF_DEQUEUE(&ifp->if_snd, m);
190		splx(s);
191		if (m)
192			m_freem(m);
193	} while (m);
194
195	if (ifp->if_flags & IFF_UP) {
196		s = splimp();
197		if_down(ifp);
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
229	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
230		if (ifa->ifa_addr->sa_family == AF_INET) {
231		    struct sockaddr_in *si;
232
233		    si = (struct sockaddr_in *)ifa->ifa_addr;
234		    if (si && si->sin_addr.s_addr)
235			    tp->tun_flags |= TUN_IASET;
236
237		    si = (struct sockaddr_in *)ifa->ifa_dstaddr;
238		    if (si && si->sin_addr.s_addr)
239			    tp->tun_flags |= TUN_DSTADDR;
240		}
241
242	return 0;
243}
244
245/*
246 * Process an ioctl request.
247 */
248int
249tunifioctl(ifp, cmd, data)
250	struct ifnet *ifp;
251	int	cmd;
252	caddr_t	data;
253{
254	register struct ifreq *ifr = (struct ifreq *)data;
255	int		error = 0, s;
256
257	s = splimp();
258	switch(cmd) {
259	case SIOCSIFADDR:
260		tuninit(ifp->if_unit);
261		TUNDEBUG("%s%d: address set\n",
262			 ifp->if_name, ifp->if_unit);
263		break;
264	case SIOCSIFDSTADDR:
265		tuninit(ifp->if_unit);
266		TUNDEBUG("%s%d: destination address set\n",
267			 ifp->if_name, ifp->if_unit);
268		break;
269	case SIOCADDMULTI:
270	case SIOCDELMULTI:
271		if (ifr == 0) {
272			error = EAFNOSUPPORT;		/* XXX */
273			break;
274		}
275		switch (ifr->ifr_addr.sa_family) {
276
277#ifdef INET
278		case AF_INET:
279			break;
280#endif
281
282		default:
283			error = EAFNOSUPPORT;
284			break;
285		}
286		break;
287
288
289	default:
290		error = EINVAL;
291	}
292	splx(s);
293	return (error);
294}
295
296/*
297 * tunoutput - queue packets from higher level ready to put out.
298 */
299int
300tunoutput(ifp, m0, dst, rt)
301	struct ifnet   *ifp;
302	struct mbuf    *m0;
303	struct sockaddr *dst;
304	struct rtentry *rt;
305{
306	struct tun_softc *tp = &tunctl[ifp->if_unit];
307	struct proc	*p;
308	int		s;
309
310	TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit);
311
312	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
313		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
314			  ifp->if_unit, tp->tun_flags);
315		m_freem (m0);
316		return EHOSTDOWN;
317	}
318
319#if NBPFILTER > 0
320	/* BPF write needs to be handled specially */
321	if (dst->sa_family == AF_UNSPEC) {
322		dst->sa_family = *(mtod(m0, int *));
323		m0->m_len -= sizeof(int);
324		m0->m_pkthdr.len -= sizeof(int);
325		m0->m_data += sizeof(int);
326	}
327
328	if (ifp->if_bpf) {
329		/*
330		 * We need to prepend the address family as
331		 * a four byte field.  Cons up a dummy header
332		 * to pacify bpf.  This is safe because bpf
333		 * will only read from the mbuf (i.e., it won't
334		 * try to free it or keep a pointer to it).
335		 */
336		struct mbuf m;
337		u_int af = dst->sa_family;
338
339		m.m_next = m0;
340		m.m_len = 4;
341		m.m_data = (char *)&af;
342
343		bpf_mtap(ifp, &m);
344	}
345#endif
346
347	switch(dst->sa_family) {
348#ifdef INET
349	case AF_INET:
350		s = splimp();
351		if (IF_QFULL(&ifp->if_snd)) {
352			IF_DROP(&ifp->if_snd);
353			m_freem(m0);
354			splx(s);
355			ifp->if_collisions++;
356			return (ENOBUFS);
357		}
358		IF_ENQUEUE(&ifp->if_snd, m0);
359		splx(s);
360		ifp->if_opackets++;
361		break;
362#endif
363	default:
364		m_freem(m0);
365		return EAFNOSUPPORT;
366	}
367
368	if (tp->tun_flags & TUN_RWAIT) {
369		tp->tun_flags &= ~TUN_RWAIT;
370		wakeup((caddr_t)tp);
371	}
372	if (tp->tun_flags & TUN_ASYNC && tp->tun_pgrp) {
373		if (tp->tun_pgrp > 0)
374			gsignal(tp->tun_pgrp, SIGIO);
375		else if ((p = pfind(-tp->tun_pgrp)) != 0)
376			psignal(p, SIGIO);
377	}
378	selwakeup(&tp->tun_rsel);
379	return 0;
380}
381
382/*
383 * the cdevsw interface is now pretty minimal.
384 */
385static	int
386tunioctl(dev, cmd, data, flag, p)
387	dev_t		dev;
388	int		cmd;
389	caddr_t		data;
390	int		flag;
391	struct proc	*p;
392{
393	int		unit = minor(dev), s;
394	struct tun_softc *tp = &tunctl[unit];
395 	struct tuninfo *tunp;
396
397	switch (cmd) {
398 	case TUNSIFINFO:
399 	        tunp = (struct tuninfo *)data;
400 		tp->tun_if.if_mtu = tunp->mtu;
401 		tp->tun_if.if_type = tunp->type;
402 		tp->tun_if.if_baudrate = tunp->baudrate;
403 		break;
404 	case TUNGIFINFO:
405 		tunp = (struct tuninfo *)data;
406 		tunp->mtu = tp->tun_if.if_mtu;
407 		tunp->type = tp->tun_if.if_type;
408 		tunp->baudrate = tp->tun_if.if_baudrate;
409 		break;
410	case TUNSDEBUG:
411		tundebug = *(int *)data;
412		break;
413	case TUNGDEBUG:
414		*(int *)data = tundebug;
415		break;
416	case FIONBIO:
417		if (*(int *)data)
418			tp->tun_flags |= TUN_NBIO;
419		else
420			tp->tun_flags &= ~TUN_NBIO;
421		break;
422	case FIOASYNC:
423		if (*(int *)data)
424			tp->tun_flags |= TUN_ASYNC;
425		else
426			tp->tun_flags &= ~TUN_ASYNC;
427		break;
428	case FIONREAD:
429		s = splimp();
430		if (tp->tun_if.if_snd.ifq_head) {
431			struct mbuf *mb = tp->tun_if.if_snd.ifq_head;
432			for( *(int *)data = 0; mb != 0; mb = mb->m_next)
433				*(int *)data += mb->m_len;
434		} else
435			*(int *)data = 0;
436		splx(s);
437		break;
438	case TIOCSPGRP:
439		tp->tun_pgrp = *(int *)data;
440		break;
441	case TIOCGPGRP:
442		*(int *)data = tp->tun_pgrp;
443		break;
444	default:
445		return (ENOTTY);
446	}
447	return (0);
448}
449
450/*
451 * The cdevsw read interface - reads a packet at a time, or at
452 * least as much of a packet as can be read.
453 */
454static	int
455tunread(dev_t dev, struct uio *uio, int flag)
456{
457	int		unit = minor(dev);
458	struct tun_softc *tp = &tunctl[unit];
459	struct ifnet	*ifp = &tp->tun_if;
460	struct mbuf	*m, *m0;
461	int		error=0, len, s;
462
463	TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit);
464	if ((tp->tun_flags & TUN_READY) != TUN_READY) {
465		TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
466			  ifp->if_unit, tp->tun_flags);
467		return EHOSTDOWN;
468	}
469
470	tp->tun_flags &= ~TUN_RWAIT;
471
472	s = splimp();
473	do {
474		IF_DEQUEUE(&ifp->if_snd, m0);
475		if (m0 == 0) {
476			if (tp->tun_flags & TUN_NBIO) {
477				splx(s);
478				return EWOULDBLOCK;
479			}
480			tp->tun_flags |= TUN_RWAIT;
481			tsleep((caddr_t)tp, PZERO + 1, "tunread", 0);
482		}
483	} while (m0 == 0);
484	splx(s);
485
486	while (m0 && uio->uio_resid > 0 && error == 0) {
487		len = min(uio->uio_resid, m0->m_len);
488		if (len == 0)
489			break;
490		error = uiomove(mtod(m0, caddr_t), len, uio);
491		MFREE(m0, m);
492		m0 = m;
493	}
494
495	if (m0) {
496		TUNDEBUG("Dropping mbuf\n");
497		m_freem(m0);
498	}
499	return error;
500}
501
502/*
503 * the cdevsw write interface - an atomic write is a packet - or else!
504 */
505static	int
506tunwrite(dev_t dev, struct uio *uio, int flag)
507{
508	int		unit = minor (dev);
509	struct ifnet	*ifp = &tunctl[unit].tun_if;
510	struct mbuf	*top, **mp, *m;
511	int		error=0, s, tlen, mlen;
512
513	TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
514
515	if (uio->uio_resid < 0 || uio->uio_resid > TUNMTU) {
516		TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit,
517		    uio->uio_resid);
518		return EIO;
519	}
520	tlen = uio->uio_resid;
521
522	/* get a header mbuf */
523	MGETHDR(m, M_DONTWAIT, MT_DATA);
524	if (m == NULL)
525		return ENOBUFS;
526	mlen = MHLEN;
527
528	top = 0;
529	mp = &top;
530	while (error == 0 && uio->uio_resid > 0) {
531		m->m_len = min(mlen, uio->uio_resid);
532		error = uiomove(mtod (m, caddr_t), m->m_len, uio);
533		*mp = m;
534		mp = &m->m_next;
535		if (uio->uio_resid > 0) {
536			MGET (m, M_DONTWAIT, MT_DATA);
537			if (m == 0) {
538				error = ENOBUFS;
539				break;
540			}
541			mlen = MLEN;
542		}
543	}
544	if (error) {
545		if (top)
546			m_freem (top);
547		return error;
548	}
549
550	top->m_pkthdr.len = tlen;
551	top->m_pkthdr.rcvif = ifp;
552
553#if NBPFILTER > 0
554	if (ifp->if_bpf) {
555		/*
556		 * We need to prepend the address family as
557		 * a four byte field.  Cons up a dummy header
558		 * to pacify bpf.  This is safe because bpf
559		 * will only read from the mbuf (i.e., it won't
560		 * try to free it or keep a pointer to it).
561		 */
562		struct mbuf m;
563		u_int af = AF_INET;
564
565		m.m_next = top;
566		m.m_len = 4;
567		m.m_data = (char *)&af;
568
569		bpf_mtap(ifp, &m);
570	}
571#endif
572
573	s = splimp();
574	if (IF_QFULL (&ipintrq)) {
575		IF_DROP(&ipintrq);
576		splx(s);
577		ifp->if_collisions++;
578		m_freem(top);
579		return ENOBUFS;
580	}
581	IF_ENQUEUE(&ipintrq, top);
582	splx(s);
583	ifp->if_ipackets++;
584	schednetisr(NETISR_IP);
585	return error;
586}
587
588/*
589 * tunselect - the select interface, this is only useful on reads
590 * really. The write detect always returns true, write never blocks
591 * anyway, it either accepts the packet or drops it.
592 */
593static	int
594tunselect(dev_t dev, int rw, struct proc *p)
595{
596	int		unit = minor(dev), s;
597	struct tun_softc *tp = &tunctl[unit];
598	struct ifnet	*ifp = &tp->tun_if;
599
600	s = splimp();
601	TUNDEBUG("%s%d: tunselect\n", ifp->if_name, ifp->if_unit);
602
603	switch (rw) {
604	case FREAD:
605		if (ifp->if_snd.ifq_len > 0) {
606			splx(s);
607			TUNDEBUG("%s%d: tunselect q=%d\n", ifp->if_name,
608			    ifp->if_unit, ifp->if_snd.ifq_len);
609			return 1;
610		}
611		selrecord(p, &tp->tun_rsel);
612		break;
613	case FWRITE:
614		splx(s);
615		return 1;
616	}
617	splx(s);
618	TUNDEBUG("%s%d: tunselect waiting\n", ifp->if_name, ifp->if_unit);
619	return 0;
620}
621
622
623#endif  /* NTUN */
624