1/*-
2 * Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@FreeBSD.org>
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 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/param.h>
28#include <sys/systm.h>
29#include <sys/jail.h>
30#include <sys/kernel.h>
31#include <sys/lock.h>
32#include <sys/malloc.h>
33#include <sys/module.h>
34#include <sys/mbuf.h>
35#include <sys/priv.h>
36#include <sys/proc.h>
37#include <sys/socket.h>
38#include <sys/sockio.h>
39#include <sys/sx.h>
40#include <sys/sysctl.h>
41#include <sys/syslog.h>
42
43#include <net/bpf.h>
44#include <net/ethernet.h>
45#include <net/if.h>
46#include <net/if_var.h>
47#include <net/if_private.h>
48#include <net/if_clone.h>
49#include <net/if_types.h>
50#include <net/netisr.h>
51#include <net/vnet.h>
52#include <net/route.h>
53
54#include <netinet/in.h>
55#include <netinet/in_systm.h>
56#include <netinet/in_var.h>
57#include <netinet/ip.h>
58#include <netinet/ip_var.h>
59#include <netinet/ip_encap.h>
60
61#include <machine/in_cksum.h>
62#include <security/mac/mac_framework.h>
63
64#define	MEMTU			(1500 - sizeof(struct mobhdr))
65static const char mename[] = "me";
66static MALLOC_DEFINE(M_IFME, mename, "Minimal Encapsulation for IP");
67/* Minimal forwarding header RFC 2004 */
68struct mobhdr {
69	uint8_t		mob_proto;	/* protocol */
70	uint8_t		mob_flags;	/* flags */
71#define	MOB_FLAGS_SP	0x80		/* source present */
72	uint16_t	mob_csum;	/* header checksum */
73	struct in_addr	mob_dst;	/* original destination address */
74	struct in_addr	mob_src;	/* original source addr (optional) */
75} __packed;
76
77struct me_softc {
78	struct ifnet		*me_ifp;
79	u_int			me_fibnum;
80	struct in_addr		me_src;
81	struct in_addr		me_dst;
82
83	CK_LIST_ENTRY(me_softc) chain;
84	CK_LIST_ENTRY(me_softc) srchash;
85};
86CK_LIST_HEAD(me_list, me_softc);
87#define	ME2IFP(sc)		((sc)->me_ifp)
88#define	ME_READY(sc)		((sc)->me_src.s_addr != 0)
89#define	ME_RLOCK_TRACKER	struct epoch_tracker me_et
90#define	ME_RLOCK()		epoch_enter_preempt(net_epoch_preempt, &me_et)
91#define	ME_RUNLOCK()		epoch_exit_preempt(net_epoch_preempt, &me_et)
92#define	ME_WAIT()		epoch_wait_preempt(net_epoch_preempt)
93
94#ifndef ME_HASH_SIZE
95#define	ME_HASH_SIZE	(1 << 4)
96#endif
97VNET_DEFINE_STATIC(struct me_list *, me_hashtbl) = NULL;
98VNET_DEFINE_STATIC(struct me_list *, me_srchashtbl) = NULL;
99#define	V_me_hashtbl		VNET(me_hashtbl)
100#define	V_me_srchashtbl		VNET(me_srchashtbl)
101#define	ME_HASH(src, dst)	(V_me_hashtbl[\
102    me_hashval((src), (dst)) & (ME_HASH_SIZE - 1)])
103#define	ME_SRCHASH(src)		(V_me_srchashtbl[\
104    fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (ME_HASH_SIZE - 1)])
105
106static struct sx me_ioctl_sx;
107SX_SYSINIT(me_ioctl_sx, &me_ioctl_sx, "me_ioctl");
108
109static int	me_clone_create(struct if_clone *, int, caddr_t);
110static void	me_clone_destroy(struct ifnet *);
111VNET_DEFINE_STATIC(struct if_clone *, me_cloner);
112#define	V_me_cloner	VNET(me_cloner)
113
114#ifdef VIMAGE
115static void	me_reassign(struct ifnet *, struct vnet *, char *);
116#endif
117static void	me_qflush(struct ifnet *);
118static int	me_transmit(struct ifnet *, struct mbuf *);
119static int	me_ioctl(struct ifnet *, u_long, caddr_t);
120static int	me_output(struct ifnet *, struct mbuf *,
121		    const struct sockaddr *, struct route *);
122static int	me_input(struct mbuf *, int, int, void *);
123
124static int	me_set_tunnel(struct me_softc *, in_addr_t, in_addr_t);
125static void	me_delete_tunnel(struct me_softc *);
126
127SYSCTL_DECL(_net_link);
128static SYSCTL_NODE(_net_link, IFT_TUNNEL, me, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
129    "Minimal Encapsulation for IP (RFC 2004)");
130#ifndef MAX_ME_NEST
131#define MAX_ME_NEST 1
132#endif
133
134VNET_DEFINE_STATIC(int, max_me_nesting) = MAX_ME_NEST;
135#define	V_max_me_nesting	VNET(max_me_nesting)
136SYSCTL_INT(_net_link_me, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
137    &VNET_NAME(max_me_nesting), 0, "Max nested tunnels");
138
139static uint32_t
140me_hashval(in_addr_t src, in_addr_t dst)
141{
142	uint32_t ret;
143
144	ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
145	return (fnv_32_buf(&dst, sizeof(dst), ret));
146}
147
148static struct me_list *
149me_hashinit(void)
150{
151	struct me_list *hash;
152	int i;
153
154	hash = malloc(sizeof(struct me_list) * ME_HASH_SIZE,
155	    M_IFME, M_WAITOK);
156	for (i = 0; i < ME_HASH_SIZE; i++)
157		CK_LIST_INIT(&hash[i]);
158
159	return (hash);
160}
161
162static void
163vnet_me_init(const void *unused __unused)
164{
165
166	V_me_cloner = if_clone_simple(mename, me_clone_create,
167	    me_clone_destroy, 0);
168}
169VNET_SYSINIT(vnet_me_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
170    vnet_me_init, NULL);
171
172static void
173vnet_me_uninit(const void *unused __unused)
174{
175
176	if (V_me_hashtbl != NULL) {
177		free(V_me_hashtbl, M_IFME);
178		V_me_hashtbl = NULL;
179		ME_WAIT();
180		free(V_me_srchashtbl, M_IFME);
181	}
182	if_clone_detach(V_me_cloner);
183}
184VNET_SYSUNINIT(vnet_me_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
185    vnet_me_uninit, NULL);
186
187static int
188me_clone_create(struct if_clone *ifc, int unit, caddr_t params)
189{
190	struct me_softc *sc;
191
192	sc = malloc(sizeof(struct me_softc), M_IFME, M_WAITOK | M_ZERO);
193	sc->me_fibnum = curthread->td_proc->p_fibnum;
194	ME2IFP(sc) = if_alloc(IFT_TUNNEL);
195	ME2IFP(sc)->if_softc = sc;
196	if_initname(ME2IFP(sc), mename, unit);
197
198	ME2IFP(sc)->if_mtu = MEMTU;
199	ME2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
200	ME2IFP(sc)->if_output = me_output;
201	ME2IFP(sc)->if_ioctl = me_ioctl;
202	ME2IFP(sc)->if_transmit = me_transmit;
203	ME2IFP(sc)->if_qflush = me_qflush;
204#ifdef VIMAGE
205	ME2IFP(sc)->if_reassign = me_reassign;
206#endif
207	ME2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
208	ME2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
209	if_attach(ME2IFP(sc));
210	bpfattach(ME2IFP(sc), DLT_NULL, sizeof(u_int32_t));
211	return (0);
212}
213
214#ifdef VIMAGE
215static void
216me_reassign(struct ifnet *ifp, struct vnet *new_vnet __unused,
217    char *unused __unused)
218{
219	struct me_softc *sc;
220
221	sx_xlock(&me_ioctl_sx);
222	sc = ifp->if_softc;
223	if (sc != NULL)
224		me_delete_tunnel(sc);
225	sx_xunlock(&me_ioctl_sx);
226}
227#endif /* VIMAGE */
228
229static void
230me_clone_destroy(struct ifnet *ifp)
231{
232	struct me_softc *sc;
233
234	sx_xlock(&me_ioctl_sx);
235	sc = ifp->if_softc;
236	me_delete_tunnel(sc);
237	bpfdetach(ifp);
238	if_detach(ifp);
239	ifp->if_softc = NULL;
240	sx_xunlock(&me_ioctl_sx);
241
242	ME_WAIT();
243	if_free(ifp);
244	free(sc, M_IFME);
245}
246
247static int
248me_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
249{
250	struct ifreq *ifr = (struct ifreq *)data;
251	struct sockaddr_in *src, *dst;
252	struct me_softc *sc;
253	int error;
254
255	switch (cmd) {
256	case SIOCSIFMTU:
257		if (ifr->ifr_mtu < 576)
258			return (EINVAL);
259		ifp->if_mtu = ifr->ifr_mtu;
260		return (0);
261	case SIOCSIFADDR:
262		ifp->if_flags |= IFF_UP;
263	case SIOCSIFFLAGS:
264	case SIOCADDMULTI:
265	case SIOCDELMULTI:
266		return (0);
267	}
268	sx_xlock(&me_ioctl_sx);
269	sc = ifp->if_softc;
270	if (sc == NULL) {
271		error = ENXIO;
272		goto end;
273	}
274	error = 0;
275	switch (cmd) {
276	case SIOCSIFPHYADDR:
277		src = &((struct in_aliasreq *)data)->ifra_addr;
278		dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
279		if (src->sin_family != dst->sin_family ||
280		    src->sin_family != AF_INET ||
281		    src->sin_len != dst->sin_len ||
282		    src->sin_len != sizeof(struct sockaddr_in)) {
283			error = EINVAL;
284			break;
285		}
286		if (src->sin_addr.s_addr == INADDR_ANY ||
287		    dst->sin_addr.s_addr == INADDR_ANY) {
288			error = EADDRNOTAVAIL;
289			break;
290		}
291		error = me_set_tunnel(sc, src->sin_addr.s_addr,
292		    dst->sin_addr.s_addr);
293		break;
294	case SIOCDIFPHYADDR:
295		me_delete_tunnel(sc);
296		break;
297	case SIOCGIFPSRCADDR:
298	case SIOCGIFPDSTADDR:
299		if (!ME_READY(sc)) {
300			error = EADDRNOTAVAIL;
301			break;
302		}
303		src = (struct sockaddr_in *)&ifr->ifr_addr;
304		memset(src, 0, sizeof(*src));
305		src->sin_family = AF_INET;
306		src->sin_len = sizeof(*src);
307		switch (cmd) {
308		case SIOCGIFPSRCADDR:
309			src->sin_addr = sc->me_src;
310			break;
311		case SIOCGIFPDSTADDR:
312			src->sin_addr = sc->me_dst;
313			break;
314		}
315		error = prison_if(curthread->td_ucred, sintosa(src));
316		if (error != 0)
317			memset(src, 0, sizeof(*src));
318		break;
319	case SIOCGTUNFIB:
320		ifr->ifr_fib = sc->me_fibnum;
321		break;
322	case SIOCSTUNFIB:
323		if ((error = priv_check(curthread, PRIV_NET_ME)) != 0)
324			break;
325		if (ifr->ifr_fib >= rt_numfibs)
326			error = EINVAL;
327		else
328			sc->me_fibnum = ifr->ifr_fib;
329		break;
330	default:
331		error = EINVAL;
332		break;
333	}
334end:
335	sx_xunlock(&me_ioctl_sx);
336	return (error);
337}
338
339static int
340me_lookup(const struct mbuf *m, int off, int proto, void **arg)
341{
342	const struct ip *ip;
343	struct me_softc *sc;
344
345	if (V_me_hashtbl == NULL)
346		return (0);
347
348	NET_EPOCH_ASSERT();
349	ip = mtod(m, const struct ip *);
350	CK_LIST_FOREACH(sc, &ME_HASH(ip->ip_dst.s_addr,
351	    ip->ip_src.s_addr), chain) {
352		if (sc->me_src.s_addr == ip->ip_dst.s_addr &&
353		    sc->me_dst.s_addr == ip->ip_src.s_addr) {
354			if ((ME2IFP(sc)->if_flags & IFF_UP) == 0)
355				return (0);
356			*arg = sc;
357			return (ENCAP_DRV_LOOKUP);
358		}
359	}
360	return (0);
361}
362
363/*
364 * Check that ingress address belongs to local host.
365 */
366static void
367me_set_running(struct me_softc *sc)
368{
369
370	if (in_localip(sc->me_src))
371		ME2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
372	else
373		ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
374}
375
376/*
377 * ifaddr_event handler.
378 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
379 * source address spoofing.
380 */
381static void
382me_srcaddr(void *arg __unused, const struct sockaddr *sa,
383    int event __unused)
384{
385	const struct sockaddr_in *sin;
386	struct me_softc *sc;
387
388	/* Check that VNET is ready */
389	if (V_me_hashtbl == NULL)
390		return;
391
392	NET_EPOCH_ASSERT();
393	sin = (const struct sockaddr_in *)sa;
394	CK_LIST_FOREACH(sc, &ME_SRCHASH(sin->sin_addr.s_addr), srchash) {
395		if (sc->me_src.s_addr != sin->sin_addr.s_addr)
396			continue;
397		me_set_running(sc);
398	}
399}
400
401static int
402me_set_tunnel(struct me_softc *sc, in_addr_t src, in_addr_t dst)
403{
404	struct epoch_tracker et;
405	struct me_softc *tmp;
406
407	sx_assert(&me_ioctl_sx, SA_XLOCKED);
408
409	if (V_me_hashtbl == NULL) {
410		V_me_hashtbl = me_hashinit();
411		V_me_srchashtbl = me_hashinit();
412	}
413
414	if (sc->me_src.s_addr == src && sc->me_dst.s_addr == dst)
415		return (0);
416
417	CK_LIST_FOREACH(tmp, &ME_HASH(src, dst), chain) {
418		if (tmp == sc)
419			continue;
420		if (tmp->me_src.s_addr == src &&
421		    tmp->me_dst.s_addr == dst)
422			return (EADDRNOTAVAIL);
423	}
424
425	me_delete_tunnel(sc);
426	sc->me_dst.s_addr = dst;
427	sc->me_src.s_addr = src;
428	CK_LIST_INSERT_HEAD(&ME_HASH(src, dst), sc, chain);
429	CK_LIST_INSERT_HEAD(&ME_SRCHASH(src), sc, srchash);
430
431	NET_EPOCH_ENTER(et);
432	me_set_running(sc);
433	NET_EPOCH_EXIT(et);
434	if_link_state_change(ME2IFP(sc), LINK_STATE_UP);
435	return (0);
436}
437
438static void
439me_delete_tunnel(struct me_softc *sc)
440{
441
442	sx_assert(&me_ioctl_sx, SA_XLOCKED);
443	if (ME_READY(sc)) {
444		CK_LIST_REMOVE(sc, chain);
445		CK_LIST_REMOVE(sc, srchash);
446		ME_WAIT();
447
448		sc->me_src.s_addr = 0;
449		sc->me_dst.s_addr = 0;
450		ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
451		if_link_state_change(ME2IFP(sc), LINK_STATE_DOWN);
452	}
453}
454
455static uint16_t
456me_in_cksum(uint16_t *p, int nwords)
457{
458	uint32_t sum = 0;
459
460	while (nwords-- > 0)
461		sum += *p++;
462	sum = (sum >> 16) + (sum & 0xffff);
463	sum += (sum >> 16);
464	return (~sum);
465}
466
467static int
468me_input(struct mbuf *m, int off, int proto, void *arg)
469{
470	struct me_softc *sc = arg;
471	struct mobhdr *mh;
472	struct ifnet *ifp;
473	struct ip *ip;
474	int hlen;
475
476	NET_EPOCH_ASSERT();
477
478	ifp = ME2IFP(sc);
479	/* checks for short packets */
480	hlen = sizeof(struct mobhdr);
481	if (m->m_pkthdr.len < sizeof(struct ip) + hlen)
482		hlen -= sizeof(struct in_addr);
483	if (m->m_len < sizeof(struct ip) + hlen)
484		m = m_pullup(m, sizeof(struct ip) + hlen);
485	if (m == NULL)
486		goto drop;
487	mh = (struct mobhdr *)mtodo(m, sizeof(struct ip));
488	/* check for wrong flags */
489	if (mh->mob_flags & (~MOB_FLAGS_SP)) {
490		m_freem(m);
491		goto drop;
492	}
493	if (mh->mob_flags) {
494	       if (hlen != sizeof(struct mobhdr)) {
495			m_freem(m);
496			goto drop;
497	       }
498	} else
499		hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
500	/* check mobile header checksum */
501	if (me_in_cksum((uint16_t *)mh, hlen / sizeof(uint16_t)) != 0) {
502		m_freem(m);
503		goto drop;
504	}
505#ifdef MAC
506	mac_ifnet_create_mbuf(ifp, m);
507#endif
508	ip = mtod(m, struct ip *);
509	ip->ip_dst = mh->mob_dst;
510	ip->ip_p = mh->mob_proto;
511	ip->ip_sum = 0;
512	ip->ip_len = htons(m->m_pkthdr.len - hlen);
513	if (mh->mob_flags)
514		ip->ip_src = mh->mob_src;
515	memmove(mtodo(m, hlen), ip, sizeof(struct ip));
516	m_adj(m, hlen);
517	m_clrprotoflags(m);
518	m->m_pkthdr.rcvif = ifp;
519	m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
520	M_SETFIB(m, ifp->if_fib);
521	hlen = AF_INET;
522	BPF_MTAP2(ifp, &hlen, sizeof(hlen), m);
523	if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
524	if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
525	if ((ifp->if_flags & IFF_MONITOR) != 0)
526		m_freem(m);
527	else
528		netisr_dispatch(NETISR_IP, m);
529	return (IPPROTO_DONE);
530drop:
531	if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
532	return (IPPROTO_DONE);
533}
534
535static int
536me_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
537   struct route *ro)
538{
539	uint32_t af;
540
541	/* BPF writes need to be handled specially. */
542	if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
543		bcopy(dst->sa_data, &af, sizeof(af));
544	else
545		af = RO_GET_FAMILY(ro, dst);
546	m->m_pkthdr.csum_data = af;
547	return (ifp->if_transmit(ifp, m));
548}
549
550#define	MTAG_ME	1414491977
551static int
552me_transmit(struct ifnet *ifp, struct mbuf *m)
553{
554	ME_RLOCK_TRACKER;
555	struct mobhdr mh;
556	struct me_softc *sc;
557	struct ip *ip;
558	uint32_t af;
559	int error, hlen, plen;
560
561	ME_RLOCK();
562#ifdef MAC
563	error = mac_ifnet_check_transmit(ifp, m);
564	if (error != 0)
565		goto drop;
566#endif
567	error = ENETDOWN;
568	sc = ifp->if_softc;
569	if (sc == NULL || !ME_READY(sc) ||
570	    (ifp->if_flags & IFF_MONITOR) != 0 ||
571	    (ifp->if_flags & IFF_UP) == 0 ||
572	    (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
573	    (error = if_tunnel_check_nesting(ifp, m, MTAG_ME,
574		V_max_me_nesting)) != 0) {
575		m_freem(m);
576		goto drop;
577	}
578	af = m->m_pkthdr.csum_data;
579	if (af != AF_INET) {
580		error = EAFNOSUPPORT;
581		m_freem(m);
582		goto drop;
583	}
584	if (m->m_len < sizeof(struct ip))
585		m = m_pullup(m, sizeof(struct ip));
586	if (m == NULL) {
587		error = ENOBUFS;
588		goto drop;
589	}
590	ip = mtod(m, struct ip *);
591	/* Fragmented datagramms shouldn't be encapsulated */
592	if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
593		error = EINVAL;
594		m_freem(m);
595		goto drop;
596	}
597	mh.mob_proto = ip->ip_p;
598	mh.mob_src = ip->ip_src;
599	mh.mob_dst = ip->ip_dst;
600	if (in_hosteq(sc->me_src, ip->ip_src)) {
601		hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
602		mh.mob_flags = 0;
603	} else {
604		hlen = sizeof(struct mobhdr);
605		mh.mob_flags = MOB_FLAGS_SP;
606	}
607	BPF_MTAP2(ifp, &af, sizeof(af), m);
608	plen = m->m_pkthdr.len;
609	ip->ip_src = sc->me_src;
610	ip->ip_dst = sc->me_dst;
611	m->m_flags &= ~(M_BCAST|M_MCAST);
612	M_SETFIB(m, sc->me_fibnum);
613	M_PREPEND(m, hlen, M_NOWAIT);
614	if (m == NULL) {
615		error = ENOBUFS;
616		goto drop;
617	}
618	if (m->m_len < sizeof(struct ip) + hlen)
619		m = m_pullup(m, sizeof(struct ip) + hlen);
620	if (m == NULL) {
621		error = ENOBUFS;
622		goto drop;
623	}
624	memmove(mtod(m, void *), mtodo(m, hlen), sizeof(struct ip));
625	ip = mtod(m, struct ip *);
626	ip->ip_len = htons(m->m_pkthdr.len);
627	ip->ip_p = IPPROTO_MOBILE;
628	ip->ip_sum = 0;
629	mh.mob_csum = 0;
630	mh.mob_csum = me_in_cksum((uint16_t *)&mh, hlen / sizeof(uint16_t));
631	bcopy(&mh, mtodo(m, sizeof(struct ip)), hlen);
632	error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
633drop:
634	if (error)
635		if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
636	else {
637		if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
638		if_inc_counter(ifp, IFCOUNTER_OBYTES, plen);
639	}
640	ME_RUNLOCK();
641	return (error);
642}
643
644static void
645me_qflush(struct ifnet *ifp __unused)
646{
647
648}
649
650static const struct srcaddrtab *me_srcaddrtab = NULL;
651static const struct encaptab *ecookie = NULL;
652static const struct encap_config me_encap_cfg = {
653	.proto = IPPROTO_MOBILE,
654	.min_length = sizeof(struct ip) + sizeof(struct mobhdr) -
655	    sizeof(in_addr_t),
656	.exact_match = ENCAP_DRV_LOOKUP,
657	.lookup = me_lookup,
658	.input = me_input
659};
660
661static int
662memodevent(module_t mod, int type, void *data)
663{
664
665	switch (type) {
666	case MOD_LOAD:
667		me_srcaddrtab = ip_encap_register_srcaddr(me_srcaddr,
668		    NULL, M_WAITOK);
669		ecookie = ip_encap_attach(&me_encap_cfg, NULL, M_WAITOK);
670		break;
671	case MOD_UNLOAD:
672		ip_encap_detach(ecookie);
673		ip_encap_unregister_srcaddr(me_srcaddrtab);
674		break;
675	default:
676		return (EOPNOTSUPP);
677	}
678	return (0);
679}
680
681static moduledata_t me_mod = {
682	"if_me",
683	memodevent,
684	0
685};
686
687DECLARE_MODULE(if_me, me_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
688MODULE_VERSION(if_me, 1);
689