xref: /freebsd/sys/net/if_gif.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: if_gif.c,v 1.87 2001/10/19 08:50:27 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/jail.h>
41 #include <sys/kernel.h>
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/mbuf.h>
45 #include <sys/module.h>
46 #include <sys/rmlock.h>
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
49 #include <sys/sx.h>
50 #include <sys/errno.h>
51 #include <sys/time.h>
52 #include <sys/sysctl.h>
53 #include <sys/syslog.h>
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/protosw.h>
57 #include <sys/conf.h>
58 #include <machine/cpu.h>
59 
60 #include <net/if.h>
61 #include <net/if_var.h>
62 #include <net/if_clone.h>
63 #include <net/if_types.h>
64 #include <net/netisr.h>
65 #include <net/route.h>
66 #include <net/bpf.h>
67 #include <net/vnet.h>
68 
69 #include <netinet/in.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/ip.h>
72 #include <netinet/ip_ecn.h>
73 #ifdef	INET
74 #include <netinet/in_var.h>
75 #include <netinet/ip_var.h>
76 #endif	/* INET */
77 
78 #ifdef INET6
79 #ifndef INET
80 #include <netinet/in.h>
81 #endif
82 #include <netinet6/in6_var.h>
83 #include <netinet/ip6.h>
84 #include <netinet6/ip6_ecn.h>
85 #include <netinet6/ip6_var.h>
86 #include <netinet6/scope6_var.h>
87 #include <netinet6/ip6protosw.h>
88 #endif /* INET6 */
89 
90 #include <netinet/ip_encap.h>
91 #include <net/ethernet.h>
92 #include <net/if_bridgevar.h>
93 #include <net/if_gif.h>
94 
95 #include <security/mac/mac_framework.h>
96 
97 static const char gifname[] = "gif";
98 
99 /*
100  * gif_mtx protects a per-vnet gif_softc_list.
101  */
102 static VNET_DEFINE(struct mtx, gif_mtx);
103 #define	V_gif_mtx		VNET(gif_mtx)
104 static MALLOC_DEFINE(M_GIF, "gif", "Generic Tunnel Interface");
105 static VNET_DEFINE(LIST_HEAD(, gif_softc), gif_softc_list);
106 #define	V_gif_softc_list	VNET(gif_softc_list)
107 static struct sx gif_ioctl_sx;
108 SX_SYSINIT(gif_ioctl_sx, &gif_ioctl_sx, "gif_ioctl");
109 
110 #define	GIF_LIST_LOCK_INIT(x)		mtx_init(&V_gif_mtx, "gif_mtx", \
111 					    NULL, MTX_DEF)
112 #define	GIF_LIST_LOCK_DESTROY(x)	mtx_destroy(&V_gif_mtx)
113 #define	GIF_LIST_LOCK(x)		mtx_lock(&V_gif_mtx)
114 #define	GIF_LIST_UNLOCK(x)		mtx_unlock(&V_gif_mtx)
115 
116 void	(*ng_gif_input_p)(struct ifnet *ifp, struct mbuf **mp, int af);
117 void	(*ng_gif_input_orphan_p)(struct ifnet *ifp, struct mbuf *m, int af);
118 void	(*ng_gif_attach_p)(struct ifnet *ifp);
119 void	(*ng_gif_detach_p)(struct ifnet *ifp);
120 
121 static int	gif_check_nesting(struct ifnet *, struct mbuf *);
122 static int	gif_set_tunnel(struct ifnet *, struct sockaddr *,
123     struct sockaddr *);
124 static void	gif_delete_tunnel(struct ifnet *);
125 static int	gif_ioctl(struct ifnet *, u_long, caddr_t);
126 static int	gif_transmit(struct ifnet *, struct mbuf *);
127 static void	gif_qflush(struct ifnet *);
128 static int	gif_clone_create(struct if_clone *, int, caddr_t);
129 static void	gif_clone_destroy(struct ifnet *);
130 static VNET_DEFINE(struct if_clone *, gif_cloner);
131 #define	V_gif_cloner	VNET(gif_cloner)
132 
133 static int gifmodevent(module_t, int, void *);
134 
135 SYSCTL_DECL(_net_link);
136 static SYSCTL_NODE(_net_link, IFT_GIF, gif, CTLFLAG_RW, 0,
137     "Generic Tunnel Interface");
138 #ifndef MAX_GIF_NEST
139 /*
140  * This macro controls the default upper limitation on nesting of gif tunnels.
141  * Since, setting a large value to this macro with a careless configuration
142  * may introduce system crash, we don't allow any nestings by default.
143  * If you need to configure nested gif tunnels, you can define this macro
144  * in your kernel configuration file.  However, if you do so, please be
145  * careful to configure the tunnels so that it won't make a loop.
146  */
147 #define MAX_GIF_NEST 1
148 #endif
149 static VNET_DEFINE(int, max_gif_nesting) = MAX_GIF_NEST;
150 #define	V_max_gif_nesting	VNET(max_gif_nesting)
151 SYSCTL_INT(_net_link_gif, OID_AUTO, max_nesting, CTLFLAG_VNET | CTLFLAG_RW,
152     &VNET_NAME(max_gif_nesting), 0, "Max nested tunnels");
153 
154 /*
155  * By default, we disallow creation of multiple tunnels between the same
156  * pair of addresses.  Some applications require this functionality so
157  * we allow control over this check here.
158  */
159 #ifdef XBONEHACK
160 static VNET_DEFINE(int, parallel_tunnels) = 1;
161 #else
162 static VNET_DEFINE(int, parallel_tunnels) = 0;
163 #endif
164 #define	V_parallel_tunnels	VNET(parallel_tunnels)
165 SYSCTL_INT(_net_link_gif, OID_AUTO, parallel_tunnels,
166     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(parallel_tunnels), 0,
167     "Allow parallel tunnels?");
168 
169 /* copy from src/sys/net/if_ethersubr.c */
170 static const u_char etherbroadcastaddr[ETHER_ADDR_LEN] =
171 			{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
172 #ifndef ETHER_IS_BROADCAST
173 #define ETHER_IS_BROADCAST(addr) \
174 	(bcmp(etherbroadcastaddr, (addr), ETHER_ADDR_LEN) == 0)
175 #endif
176 
177 static int
178 gif_clone_create(struct if_clone *ifc, int unit, caddr_t params)
179 {
180 	struct gif_softc *sc;
181 
182 	sc = malloc(sizeof(struct gif_softc), M_GIF, M_WAITOK | M_ZERO);
183 	sc->gif_fibnum = curthread->td_proc->p_fibnum;
184 	GIF2IFP(sc) = if_alloc(IFT_GIF);
185 	GIF_LOCK_INIT(sc);
186 	GIF2IFP(sc)->if_softc = sc;
187 	if_initname(GIF2IFP(sc), gifname, unit);
188 
189 	GIF2IFP(sc)->if_addrlen = 0;
190 	GIF2IFP(sc)->if_mtu    = GIF_MTU;
191 	GIF2IFP(sc)->if_flags  = IFF_POINTOPOINT | IFF_MULTICAST;
192 #if 0
193 	/* turn off ingress filter */
194 	GIF2IFP(sc)->if_flags  |= IFF_LINK2;
195 #endif
196 	GIF2IFP(sc)->if_ioctl  = gif_ioctl;
197 	GIF2IFP(sc)->if_transmit  = gif_transmit;
198 	GIF2IFP(sc)->if_qflush  = gif_qflush;
199 	GIF2IFP(sc)->if_output = gif_output;
200 	GIF2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
201 	GIF2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
202 	if_attach(GIF2IFP(sc));
203 	bpfattach(GIF2IFP(sc), DLT_NULL, sizeof(u_int32_t));
204 	if (ng_gif_attach_p != NULL)
205 		(*ng_gif_attach_p)(GIF2IFP(sc));
206 
207 	GIF_LIST_LOCK();
208 	LIST_INSERT_HEAD(&V_gif_softc_list, sc, gif_list);
209 	GIF_LIST_UNLOCK();
210 	return (0);
211 }
212 
213 static void
214 gif_clone_destroy(struct ifnet *ifp)
215 {
216 	struct gif_softc *sc;
217 
218 	sx_xlock(&gif_ioctl_sx);
219 	sc = ifp->if_softc;
220 	gif_delete_tunnel(ifp);
221 	GIF_LIST_LOCK();
222 	LIST_REMOVE(sc, gif_list);
223 	GIF_LIST_UNLOCK();
224 	if (ng_gif_detach_p != NULL)
225 		(*ng_gif_detach_p)(ifp);
226 	bpfdetach(ifp);
227 	if_detach(ifp);
228 	ifp->if_softc = NULL;
229 	sx_xunlock(&gif_ioctl_sx);
230 
231 	if_free(ifp);
232 	GIF_LOCK_DESTROY(sc);
233 	free(sc, M_GIF);
234 }
235 
236 static void
237 vnet_gif_init(const void *unused __unused)
238 {
239 
240 	LIST_INIT(&V_gif_softc_list);
241 	GIF_LIST_LOCK_INIT();
242 	V_gif_cloner = if_clone_simple(gifname, gif_clone_create,
243 	    gif_clone_destroy, 0);
244 }
245 VNET_SYSINIT(vnet_gif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
246     vnet_gif_init, NULL);
247 
248 static void
249 vnet_gif_uninit(const void *unused __unused)
250 {
251 
252 	if_clone_detach(V_gif_cloner);
253 	GIF_LIST_LOCK_DESTROY();
254 }
255 VNET_SYSUNINIT(vnet_gif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
256     vnet_gif_uninit, NULL);
257 
258 static int
259 gifmodevent(module_t mod, int type, void *data)
260 {
261 
262 	switch (type) {
263 	case MOD_LOAD:
264 	case MOD_UNLOAD:
265 		break;
266 	default:
267 		return (EOPNOTSUPP);
268 	}
269 	return (0);
270 }
271 
272 static moduledata_t gif_mod = {
273 	"if_gif",
274 	gifmodevent,
275 	0
276 };
277 
278 DECLARE_MODULE(if_gif, gif_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
279 MODULE_VERSION(if_gif, 1);
280 
281 int
282 gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
283 {
284 	GIF_RLOCK_TRACKER;
285 	const struct ip *ip;
286 	struct gif_softc *sc;
287 	int ret;
288 
289 	sc = (struct gif_softc *)arg;
290 	if (sc == NULL || (GIF2IFP(sc)->if_flags & IFF_UP) == 0)
291 		return (0);
292 
293 	ret = 0;
294 	GIF_RLOCK(sc);
295 
296 	/* no physical address */
297 	if (sc->gif_family == 0)
298 		goto done;
299 
300 	switch (proto) {
301 #ifdef INET
302 	case IPPROTO_IPV4:
303 #endif
304 #ifdef INET6
305 	case IPPROTO_IPV6:
306 #endif
307 	case IPPROTO_ETHERIP:
308 		break;
309 	default:
310 		goto done;
311 	}
312 
313 	/* Bail on short packets */
314 	M_ASSERTPKTHDR(m);
315 	if (m->m_pkthdr.len < sizeof(struct ip))
316 		goto done;
317 
318 	ip = mtod(m, const struct ip *);
319 	switch (ip->ip_v) {
320 #ifdef INET
321 	case 4:
322 		if (sc->gif_family != AF_INET)
323 			goto done;
324 		ret = in_gif_encapcheck(m, off, proto, arg);
325 		break;
326 #endif
327 #ifdef INET6
328 	case 6:
329 		if (m->m_pkthdr.len < sizeof(struct ip6_hdr))
330 			goto done;
331 		if (sc->gif_family != AF_INET6)
332 			goto done;
333 		ret = in6_gif_encapcheck(m, off, proto, arg);
334 		break;
335 #endif
336 	}
337 done:
338 	GIF_RUNLOCK(sc);
339 	return (ret);
340 }
341 
342 static int
343 gif_transmit(struct ifnet *ifp, struct mbuf *m)
344 {
345 	struct gif_softc *sc;
346 	struct etherip_header *eth;
347 #ifdef INET
348 	struct ip *ip;
349 #endif
350 #ifdef INET6
351 	struct ip6_hdr *ip6;
352 	uint32_t t;
353 #endif
354 	uint32_t af;
355 	uint8_t proto, ecn;
356 	int error;
357 
358 #ifdef MAC
359 	error = mac_ifnet_check_transmit(ifp, m);
360 	if (error) {
361 		m_freem(m);
362 		goto err;
363 	}
364 #endif
365 	error = ENETDOWN;
366 	sc = ifp->if_softc;
367 	if ((ifp->if_flags & IFF_MONITOR) != 0 ||
368 	    (ifp->if_flags & IFF_UP) == 0 ||
369 	    sc->gif_family == 0 ||
370 	    (error = gif_check_nesting(ifp, m)) != 0) {
371 		m_freem(m);
372 		goto err;
373 	}
374 	/* Now pull back the af that we stashed in the csum_data. */
375 	if (ifp->if_bridge)
376 		af = AF_LINK;
377 	else
378 		af = m->m_pkthdr.csum_data;
379 	m->m_flags &= ~(M_BCAST|M_MCAST);
380 	M_SETFIB(m, sc->gif_fibnum);
381 	BPF_MTAP2(ifp, &af, sizeof(af), m);
382 	if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
383 	if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
384 	/* inner AF-specific encapsulation */
385 	ecn = 0;
386 	switch (af) {
387 #ifdef INET
388 	case AF_INET:
389 		proto = IPPROTO_IPV4;
390 		if (m->m_len < sizeof(struct ip))
391 			m = m_pullup(m, sizeof(struct ip));
392 		if (m == NULL) {
393 			error = ENOBUFS;
394 			goto err;
395 		}
396 		ip = mtod(m, struct ip *);
397 		ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED:
398 		    ECN_NOCARE, &ecn, &ip->ip_tos);
399 		break;
400 #endif
401 #ifdef INET6
402 	case AF_INET6:
403 		proto = IPPROTO_IPV6;
404 		if (m->m_len < sizeof(struct ip6_hdr))
405 			m = m_pullup(m, sizeof(struct ip6_hdr));
406 		if (m == NULL) {
407 			error = ENOBUFS;
408 			goto err;
409 		}
410 		t = 0;
411 		ip6 = mtod(m, struct ip6_hdr *);
412 		ip6_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED:
413 		    ECN_NOCARE, &t, &ip6->ip6_flow);
414 		ecn = (ntohl(t) >> 20) & 0xff;
415 		break;
416 #endif
417 	case AF_LINK:
418 		proto = IPPROTO_ETHERIP;
419 		M_PREPEND(m, sizeof(struct etherip_header), M_NOWAIT);
420 		if (m == NULL) {
421 			error = ENOBUFS;
422 			goto err;
423 		}
424 		eth = mtod(m, struct etherip_header *);
425 		eth->eip_resvh = 0;
426 		eth->eip_ver = ETHERIP_VERSION;
427 		eth->eip_resvl = 0;
428 		break;
429 	default:
430 		error = EAFNOSUPPORT;
431 		m_freem(m);
432 		goto err;
433 	}
434 	/* XXX should we check if our outer source is legal? */
435 	/* dispatch to output logic based on outer AF */
436 	switch (sc->gif_family) {
437 #ifdef INET
438 	case AF_INET:
439 		error = in_gif_output(ifp, m, proto, ecn);
440 		break;
441 #endif
442 #ifdef INET6
443 	case AF_INET6:
444 		error = in6_gif_output(ifp, m, proto, ecn);
445 		break;
446 #endif
447 	default:
448 		m_freem(m);
449 	}
450 err:
451 	if (error)
452 		if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
453 	return (error);
454 }
455 
456 static void
457 gif_qflush(struct ifnet *ifp __unused)
458 {
459 
460 }
461 
462 #define	MTAG_GIF	1080679712
463 static int
464 gif_check_nesting(struct ifnet *ifp, struct mbuf *m)
465 {
466 	struct m_tag *mtag;
467 	int count;
468 
469 	/*
470 	 * gif may cause infinite recursion calls when misconfigured.
471 	 * We'll prevent this by detecting loops.
472 	 *
473 	 * High nesting level may cause stack exhaustion.
474 	 * We'll prevent this by introducing upper limit.
475 	 */
476 	count = 1;
477 	mtag = NULL;
478 	while ((mtag = m_tag_locate(m, MTAG_GIF, 0, mtag)) != NULL) {
479 		if (*(struct ifnet **)(mtag + 1) == ifp) {
480 			log(LOG_NOTICE, "%s: loop detected\n", if_name(ifp));
481 			return (EIO);
482 		}
483 		count++;
484 	}
485 	if (count > V_max_gif_nesting) {
486 		log(LOG_NOTICE,
487 		    "%s: if_output recursively called too many times(%d)\n",
488 		    if_name(ifp), count);
489 		return (EIO);
490 	}
491 	mtag = m_tag_alloc(MTAG_GIF, 0, sizeof(struct ifnet *), M_NOWAIT);
492 	if (mtag == NULL)
493 		return (ENOMEM);
494 	*(struct ifnet **)(mtag + 1) = ifp;
495 	m_tag_prepend(m, mtag);
496 	return (0);
497 }
498 
499 int
500 gif_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
501 	struct route *ro)
502 {
503 	uint32_t af;
504 
505 	if (dst->sa_family == AF_UNSPEC)
506 		bcopy(dst->sa_data, &af, sizeof(af));
507 	else
508 		af = dst->sa_family;
509 	/*
510 	 * Now save the af in the inbound pkt csum data, this is a cheat since
511 	 * we are using the inbound csum_data field to carry the af over to
512 	 * the gif_transmit() routine, avoiding using yet another mtag.
513 	 */
514 	m->m_pkthdr.csum_data = af;
515 	return (ifp->if_transmit(ifp, m));
516 }
517 
518 void
519 gif_input(struct mbuf *m, struct ifnet *ifp, int proto, uint8_t ecn)
520 {
521 	struct etherip_header *eip;
522 #ifdef INET
523 	struct ip *ip;
524 #endif
525 #ifdef INET6
526 	struct ip6_hdr *ip6;
527 	uint32_t t;
528 #endif
529 	struct gif_softc *sc;
530 	struct ether_header *eh;
531 	struct ifnet *oldifp;
532 	int isr, n, af;
533 
534 	if (ifp == NULL) {
535 		/* just in case */
536 		m_freem(m);
537 		return;
538 	}
539 	sc = ifp->if_softc;
540 	m->m_pkthdr.rcvif = ifp;
541 	m_clrprotoflags(m);
542 	switch (proto) {
543 #ifdef INET
544 	case IPPROTO_IPV4:
545 		af = AF_INET;
546 		if (m->m_len < sizeof(struct ip))
547 			m = m_pullup(m, sizeof(struct ip));
548 		if (m == NULL)
549 			goto drop;
550 		ip = mtod(m, struct ip *);
551 		if (ip_ecn_egress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED:
552 		    ECN_NOCARE, &ecn, &ip->ip_tos) == 0) {
553 			m_freem(m);
554 			goto drop;
555 		}
556 		break;
557 #endif
558 #ifdef INET6
559 	case IPPROTO_IPV6:
560 		af = AF_INET6;
561 		if (m->m_len < sizeof(struct ip6_hdr))
562 			m = m_pullup(m, sizeof(struct ip6_hdr));
563 		if (m == NULL)
564 			goto drop;
565 		t = htonl((uint32_t)ecn << 20);
566 		ip6 = mtod(m, struct ip6_hdr *);
567 		if (ip6_ecn_egress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED:
568 		    ECN_NOCARE, &t, &ip6->ip6_flow) == 0) {
569 			m_freem(m);
570 			goto drop;
571 		}
572 		break;
573 #endif
574 	case IPPROTO_ETHERIP:
575 		af = AF_LINK;
576 		break;
577 	default:
578 		m_freem(m);
579 		goto drop;
580 	}
581 
582 #ifdef MAC
583 	mac_ifnet_create_mbuf(ifp, m);
584 #endif
585 
586 	if (bpf_peers_present(ifp->if_bpf)) {
587 		uint32_t af1 = af;
588 		bpf_mtap2(ifp->if_bpf, &af1, sizeof(af1), m);
589 	}
590 
591 	if ((ifp->if_flags & IFF_MONITOR) != 0) {
592 		if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
593 		if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
594 		m_freem(m);
595 		return;
596 	}
597 
598 	if (ng_gif_input_p != NULL) {
599 		(*ng_gif_input_p)(ifp, &m, af);
600 		if (m == NULL)
601 			goto drop;
602 	}
603 
604 	/*
605 	 * Put the packet to the network layer input queue according to the
606 	 * specified address family.
607 	 * Note: older versions of gif_input directly called network layer
608 	 * input functions, e.g. ip6_input, here.  We changed the policy to
609 	 * prevent too many recursive calls of such input functions, which
610 	 * might cause kernel panic.  But the change may introduce another
611 	 * problem; if the input queue is full, packets are discarded.
612 	 * The kernel stack overflow really happened, and we believed
613 	 * queue-full rarely occurs, so we changed the policy.
614 	 */
615 	switch (af) {
616 #ifdef INET
617 	case AF_INET:
618 		isr = NETISR_IP;
619 		break;
620 #endif
621 #ifdef INET6
622 	case AF_INET6:
623 		isr = NETISR_IPV6;
624 		break;
625 #endif
626 	case AF_LINK:
627 		n = sizeof(struct etherip_header) + sizeof(struct ether_header);
628 		if (n > m->m_len)
629 			m = m_pullup(m, n);
630 		if (m == NULL)
631 			goto drop;
632 		eip = mtod(m, struct etherip_header *);
633 		if (eip->eip_ver != ETHERIP_VERSION) {
634 			/* discard unknown versions */
635 			m_freem(m);
636 			goto drop;
637 		}
638 		m_adj(m, sizeof(struct etherip_header));
639 
640 		m->m_flags &= ~(M_BCAST|M_MCAST);
641 		m->m_pkthdr.rcvif = ifp;
642 
643 		if (ifp->if_bridge) {
644 			oldifp = ifp;
645 			eh = mtod(m, struct ether_header *);
646 			if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
647 				if (ETHER_IS_BROADCAST(eh->ether_dhost))
648 					m->m_flags |= M_BCAST;
649 				else
650 					m->m_flags |= M_MCAST;
651 				if_inc_counter(ifp, IFCOUNTER_IMCASTS, 1);
652 			}
653 			BRIDGE_INPUT(ifp, m);
654 
655 			if (m != NULL && ifp != oldifp) {
656 				/*
657 				 * The bridge gave us back itself or one of the
658 				 * members for which the frame is addressed.
659 				 */
660 				ether_demux(ifp, m);
661 				return;
662 			}
663 		}
664 		if (m != NULL)
665 			m_freem(m);
666 		return;
667 
668 	default:
669 		if (ng_gif_input_orphan_p != NULL)
670 			(*ng_gif_input_orphan_p)(ifp, m, af);
671 		else
672 			m_freem(m);
673 		return;
674 	}
675 
676 	if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
677 	if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
678 	M_SETFIB(m, ifp->if_fib);
679 	netisr_dispatch(isr, m);
680 	return;
681 drop:
682 	if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
683 }
684 
685 /* XXX how should we handle IPv6 scope on SIOC[GS]IFPHYADDR? */
686 int
687 gif_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
688 {
689 	GIF_RLOCK_TRACKER;
690 	struct ifreq *ifr = (struct ifreq*)data;
691 	struct sockaddr *dst, *src;
692 	struct gif_softc *sc;
693 #ifdef INET
694 	struct sockaddr_in *sin = NULL;
695 #endif
696 #ifdef INET6
697 	struct sockaddr_in6 *sin6 = NULL;
698 #endif
699 	u_int options;
700 	int error;
701 
702 	switch (cmd) {
703 	case SIOCSIFADDR:
704 		ifp->if_flags |= IFF_UP;
705 	case SIOCADDMULTI:
706 	case SIOCDELMULTI:
707 	case SIOCGIFMTU:
708 	case SIOCSIFFLAGS:
709 		return (0);
710 	case SIOCSIFMTU:
711 		if (ifr->ifr_mtu < GIF_MTU_MIN ||
712 		    ifr->ifr_mtu > GIF_MTU_MAX)
713 			return (EINVAL);
714 		else
715 			ifp->if_mtu = ifr->ifr_mtu;
716 		return (0);
717 	}
718 	sx_xlock(&gif_ioctl_sx);
719 	sc = ifp->if_softc;
720 	if (sc == NULL) {
721 		error = ENXIO;
722 		goto bad;
723 	}
724 	error = 0;
725 	switch (cmd) {
726 	case SIOCSIFPHYADDR:
727 #ifdef INET6
728 	case SIOCSIFPHYADDR_IN6:
729 #endif
730 		error = EINVAL;
731 		switch (cmd) {
732 #ifdef INET
733 		case SIOCSIFPHYADDR:
734 			src = (struct sockaddr *)
735 				&(((struct in_aliasreq *)data)->ifra_addr);
736 			dst = (struct sockaddr *)
737 				&(((struct in_aliasreq *)data)->ifra_dstaddr);
738 			break;
739 #endif
740 #ifdef INET6
741 		case SIOCSIFPHYADDR_IN6:
742 			src = (struct sockaddr *)
743 				&(((struct in6_aliasreq *)data)->ifra_addr);
744 			dst = (struct sockaddr *)
745 				&(((struct in6_aliasreq *)data)->ifra_dstaddr);
746 			break;
747 #endif
748 		default:
749 			goto bad;
750 		}
751 		/* sa_family must be equal */
752 		if (src->sa_family != dst->sa_family ||
753 		    src->sa_len != dst->sa_len)
754 			goto bad;
755 
756 		/* validate sa_len */
757 		/* check sa_family looks sane for the cmd */
758 		switch (src->sa_family) {
759 #ifdef INET
760 		case AF_INET:
761 			if (src->sa_len != sizeof(struct sockaddr_in))
762 				goto bad;
763 			if (cmd != SIOCSIFPHYADDR) {
764 				error = EAFNOSUPPORT;
765 				goto bad;
766 			}
767 			if (satosin(src)->sin_addr.s_addr == INADDR_ANY ||
768 			    satosin(dst)->sin_addr.s_addr == INADDR_ANY) {
769 				error = EADDRNOTAVAIL;
770 				goto bad;
771 			}
772 			break;
773 #endif
774 #ifdef INET6
775 		case AF_INET6:
776 			if (src->sa_len != sizeof(struct sockaddr_in6))
777 				goto bad;
778 			if (cmd != SIOCSIFPHYADDR_IN6) {
779 				error = EAFNOSUPPORT;
780 				goto bad;
781 			}
782 			error = EADDRNOTAVAIL;
783 			if (IN6_IS_ADDR_UNSPECIFIED(&satosin6(src)->sin6_addr)
784 			    ||
785 			    IN6_IS_ADDR_UNSPECIFIED(&satosin6(dst)->sin6_addr))
786 				goto bad;
787 			/*
788 			 * Check validity of the scope zone ID of the
789 			 * addresses, and convert it into the kernel
790 			 * internal form if necessary.
791 			 */
792 			error = sa6_embedscope(satosin6(src), 0);
793 			if (error != 0)
794 				goto bad;
795 			error = sa6_embedscope(satosin6(dst), 0);
796 			if (error != 0)
797 				goto bad;
798 			break;
799 #endif
800 		default:
801 			error = EAFNOSUPPORT;
802 			goto bad;
803 		}
804 		error = gif_set_tunnel(ifp, src, dst);
805 		break;
806 	case SIOCDIFPHYADDR:
807 		gif_delete_tunnel(ifp);
808 		break;
809 	case SIOCGIFPSRCADDR:
810 	case SIOCGIFPDSTADDR:
811 #ifdef INET6
812 	case SIOCGIFPSRCADDR_IN6:
813 	case SIOCGIFPDSTADDR_IN6:
814 #endif
815 		if (sc->gif_family == 0) {
816 			error = EADDRNOTAVAIL;
817 			break;
818 		}
819 		GIF_RLOCK(sc);
820 		switch (cmd) {
821 #ifdef INET
822 		case SIOCGIFPSRCADDR:
823 		case SIOCGIFPDSTADDR:
824 			if (sc->gif_family != AF_INET) {
825 				error = EADDRNOTAVAIL;
826 				break;
827 			}
828 			sin = (struct sockaddr_in *)&ifr->ifr_addr;
829 			memset(sin, 0, sizeof(*sin));
830 			sin->sin_family = AF_INET;
831 			sin->sin_len = sizeof(*sin);
832 			break;
833 #endif
834 #ifdef INET6
835 		case SIOCGIFPSRCADDR_IN6:
836 		case SIOCGIFPDSTADDR_IN6:
837 			if (sc->gif_family != AF_INET6) {
838 				error = EADDRNOTAVAIL;
839 				break;
840 			}
841 			sin6 = (struct sockaddr_in6 *)
842 				&(((struct in6_ifreq *)data)->ifr_addr);
843 			memset(sin6, 0, sizeof(*sin6));
844 			sin6->sin6_family = AF_INET6;
845 			sin6->sin6_len = sizeof(*sin6);
846 			break;
847 #endif
848 		default:
849 			error = EAFNOSUPPORT;
850 		}
851 		if (error == 0) {
852 			switch (cmd) {
853 #ifdef INET
854 			case SIOCGIFPSRCADDR:
855 				sin->sin_addr = sc->gif_iphdr->ip_src;
856 				break;
857 			case SIOCGIFPDSTADDR:
858 				sin->sin_addr = sc->gif_iphdr->ip_dst;
859 				break;
860 #endif
861 #ifdef INET6
862 			case SIOCGIFPSRCADDR_IN6:
863 				sin6->sin6_addr = sc->gif_ip6hdr->ip6_src;
864 				break;
865 			case SIOCGIFPDSTADDR_IN6:
866 				sin6->sin6_addr = sc->gif_ip6hdr->ip6_dst;
867 				break;
868 #endif
869 			}
870 		}
871 		GIF_RUNLOCK(sc);
872 		if (error != 0)
873 			break;
874 		switch (cmd) {
875 #ifdef INET
876 		case SIOCGIFPSRCADDR:
877 		case SIOCGIFPDSTADDR:
878 			error = prison_if(curthread->td_ucred,
879 			    (struct sockaddr *)sin);
880 			if (error != 0)
881 				memset(sin, 0, sizeof(*sin));
882 			break;
883 #endif
884 #ifdef INET6
885 		case SIOCGIFPSRCADDR_IN6:
886 		case SIOCGIFPDSTADDR_IN6:
887 			error = prison_if(curthread->td_ucred,
888 			    (struct sockaddr *)sin6);
889 			if (error == 0)
890 				error = sa6_recoverscope(sin6);
891 			if (error != 0)
892 				memset(sin6, 0, sizeof(*sin6));
893 #endif
894 		}
895 		break;
896 	case SIOCGTUNFIB:
897 		ifr->ifr_fib = sc->gif_fibnum;
898 		break;
899 	case SIOCSTUNFIB:
900 		if ((error = priv_check(curthread, PRIV_NET_GIF)) != 0)
901 			break;
902 		if (ifr->ifr_fib >= rt_numfibs)
903 			error = EINVAL;
904 		else
905 			sc->gif_fibnum = ifr->ifr_fib;
906 		break;
907 	case GIFGOPTS:
908 		options = sc->gif_options;
909 		error = copyout(&options, ifr->ifr_data, sizeof(options));
910 		break;
911 	case GIFSOPTS:
912 		if ((error = priv_check(curthread, PRIV_NET_GIF)) != 0)
913 			break;
914 		error = copyin(ifr->ifr_data, &options, sizeof(options));
915 		if (error)
916 			break;
917 		if (options & ~GIF_OPTMASK)
918 			error = EINVAL;
919 		else
920 			sc->gif_options = options;
921 		break;
922 	default:
923 		error = EINVAL;
924 		break;
925 	}
926 bad:
927 	sx_xunlock(&gif_ioctl_sx);
928 	return (error);
929 }
930 
931 static void
932 gif_detach(struct gif_softc *sc)
933 {
934 
935 	sx_assert(&gif_ioctl_sx, SA_XLOCKED);
936 	if (sc->gif_ecookie != NULL)
937 		encap_detach(sc->gif_ecookie);
938 	sc->gif_ecookie = NULL;
939 }
940 
941 static int
942 gif_attach(struct gif_softc *sc, int af)
943 {
944 
945 	sx_assert(&gif_ioctl_sx, SA_XLOCKED);
946 	switch (af) {
947 #ifdef INET
948 	case AF_INET:
949 		return (in_gif_attach(sc));
950 #endif
951 #ifdef INET6
952 	case AF_INET6:
953 		return (in6_gif_attach(sc));
954 #endif
955 	}
956 	return (EAFNOSUPPORT);
957 }
958 
959 static int
960 gif_set_tunnel(struct ifnet *ifp, struct sockaddr *src, struct sockaddr *dst)
961 {
962 	struct gif_softc *sc = ifp->if_softc;
963 	struct gif_softc *tsc;
964 #ifdef INET
965 	struct ip *ip;
966 #endif
967 #ifdef INET6
968 	struct ip6_hdr *ip6;
969 #endif
970 	void *hdr;
971 	int error = 0;
972 
973 	if (sc == NULL)
974 		return (ENXIO);
975 	/* Disallow parallel tunnels unless instructed otherwise. */
976 	if (V_parallel_tunnels == 0) {
977 		GIF_LIST_LOCK();
978 		LIST_FOREACH(tsc, &V_gif_softc_list, gif_list) {
979 			if (tsc == sc || tsc->gif_family != src->sa_family)
980 				continue;
981 #ifdef INET
982 			if (tsc->gif_family == AF_INET &&
983 			    tsc->gif_iphdr->ip_src.s_addr ==
984 			    satosin(src)->sin_addr.s_addr &&
985 			    tsc->gif_iphdr->ip_dst.s_addr ==
986 			    satosin(dst)->sin_addr.s_addr) {
987 				error = EADDRNOTAVAIL;
988 				GIF_LIST_UNLOCK();
989 				goto bad;
990 			}
991 #endif
992 #ifdef INET6
993 			if (tsc->gif_family == AF_INET6 &&
994 			    IN6_ARE_ADDR_EQUAL(&tsc->gif_ip6hdr->ip6_src,
995 			    &satosin6(src)->sin6_addr) &&
996 			    IN6_ARE_ADDR_EQUAL(&tsc->gif_ip6hdr->ip6_dst,
997 			    &satosin6(dst)->sin6_addr)) {
998 				error = EADDRNOTAVAIL;
999 				GIF_LIST_UNLOCK();
1000 				goto bad;
1001 			}
1002 #endif
1003 		}
1004 		GIF_LIST_UNLOCK();
1005 	}
1006 	switch (src->sa_family) {
1007 #ifdef INET
1008 	case AF_INET:
1009 		hdr = ip = malloc(sizeof(struct ip), M_GIF,
1010 		    M_WAITOK | M_ZERO);
1011 		ip->ip_src.s_addr = satosin(src)->sin_addr.s_addr;
1012 		ip->ip_dst.s_addr = satosin(dst)->sin_addr.s_addr;
1013 		break;
1014 #endif
1015 #ifdef INET6
1016 	case AF_INET6:
1017 		hdr = ip6 = malloc(sizeof(struct ip6_hdr), M_GIF,
1018 		    M_WAITOK | M_ZERO);
1019 		ip6->ip6_src = satosin6(src)->sin6_addr;
1020 		ip6->ip6_dst = satosin6(dst)->sin6_addr;
1021 		ip6->ip6_vfc = IPV6_VERSION;
1022 		break;
1023 #endif
1024 	default:
1025 		return (EAFNOSUPPORT);
1026 	};
1027 
1028 	if (sc->gif_family != src->sa_family)
1029 		gif_detach(sc);
1030 	if (sc->gif_family == 0 ||
1031 	    sc->gif_family != src->sa_family)
1032 		error = gif_attach(sc, src->sa_family);
1033 
1034 	GIF_WLOCK(sc);
1035 	if (sc->gif_family != 0)
1036 		free(sc->gif_hdr, M_GIF);
1037 	sc->gif_family = src->sa_family;
1038 	sc->gif_hdr = hdr;
1039 	GIF_WUNLOCK(sc);
1040 #if defined(INET) || defined(INET6)
1041 bad:
1042 #endif
1043 	if (error == 0 && sc->gif_family != 0) {
1044 		ifp->if_drv_flags |= IFF_DRV_RUNNING;
1045 		if_link_state_change(ifp, LINK_STATE_UP);
1046 	} else {
1047 		ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
1048 		if_link_state_change(ifp, LINK_STATE_DOWN);
1049 	}
1050 	return (error);
1051 }
1052 
1053 static void
1054 gif_delete_tunnel(struct ifnet *ifp)
1055 {
1056 	struct gif_softc *sc = ifp->if_softc;
1057 	int family;
1058 
1059 	if (sc == NULL)
1060 		return;
1061 
1062 	GIF_WLOCK(sc);
1063 	family = sc->gif_family;
1064 	sc->gif_family = 0;
1065 	GIF_WUNLOCK(sc);
1066 	if (family != 0) {
1067 		gif_detach(sc);
1068 		free(sc->gif_hdr, M_GIF);
1069 	}
1070 	ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
1071 	if_link_state_change(ifp, LINK_STATE_DOWN);
1072 }
1073