1/*	$NetBSD: in6_gif.c,v 1.96 2022/12/07 08:30:15 knakahara Exp $	*/
2/*	$KAME: in6_gif.c,v 1.62 2001/07/29 04:27:25 itojun Exp $	*/
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__KERNEL_RCSID(0, "$NetBSD: in6_gif.c,v 1.96 2022/12/07 08:30:15 knakahara Exp $");
35
36#ifdef _KERNEL_OPT
37#include "opt_inet.h"
38#endif
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/socket.h>
43#include <sys/sockio.h>
44#include <sys/mbuf.h>
45#include <sys/errno.h>
46#include <sys/ioctl.h>
47#include <sys/queue.h>
48#include <sys/syslog.h>
49#include <sys/kernel.h>
50
51#include <net/if.h>
52#include <net/route.h>
53
54#include <netinet/in.h>
55#include <netinet/in_systm.h>
56#ifdef INET
57#include <netinet/ip.h>
58#endif
59#include <netinet/ip_encap.h>
60#ifdef INET6
61#include <netinet/ip6.h>
62#include <netinet6/ip6_var.h>
63#include <netinet6/ip6_private.h>
64#include <netinet6/in6_gif.h>
65#include <netinet6/in6_var.h>
66#endif
67#include <netinet6/ip6protosw.h> /* for struct ip6ctlparam */
68#include <netinet/ip_ecn.h>
69
70#include <net/if_gif.h>
71
72static int gif_validate6(const struct ip6_hdr *, struct gif_variant *,
73	struct ifnet *);
74
75int	ip6_gif_hlim = GIF_HLIM;
76int	ip6_gif_pmtu = 0;
77
78static const struct encapsw in6_gif_encapsw;
79
80/*
81 * family - family of the packet to be encapsulate.
82 */
83
84static int
85in6_gif_output(struct gif_variant *var, int family, struct mbuf *m)
86{
87	struct rtentry *rt;
88	struct gif_softc *sc;
89	struct sockaddr_in6 *sin6_src;
90	struct sockaddr_in6 *sin6_dst;
91	struct ifnet *ifp;
92	struct ip6_hdr *ip6;
93	struct route *ro_pc;
94	kmutex_t *lock_pc;
95	int proto, error;
96	u_int8_t itos, otos;
97
98	KASSERT(gif_heldref_variant(var));
99
100	sin6_src = satosin6(var->gv_psrc);
101	sin6_dst = satosin6(var->gv_pdst);
102	ifp = &var->gv_softc->gif_if;
103
104	if (sin6_src == NULL || sin6_dst == NULL ||
105	    sin6_src->sin6_family != AF_INET6 ||
106	    sin6_dst->sin6_family != AF_INET6) {
107		m_freem(m);
108		return EAFNOSUPPORT;
109	}
110
111	switch (family) {
112#ifdef INET
113	case AF_INET:
114	    {
115		struct ip *ip;
116
117		proto = IPPROTO_IPV4;
118		if (m->m_len < sizeof(*ip)) {
119			m = m_pullup(m, sizeof(*ip));
120			if (!m)
121				return ENOBUFS;
122		}
123		ip = mtod(m, struct ip *);
124		itos = ip->ip_tos;
125		break;
126	    }
127#endif
128#ifdef INET6
129	case AF_INET6:
130	    {
131		proto = IPPROTO_IPV6;
132		if (m->m_len < sizeof(*ip6)) {
133			m = m_pullup(m, sizeof(*ip6));
134			if (!m)
135				return ENOBUFS;
136		}
137		ip6 = mtod(m, struct ip6_hdr *);
138		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139		break;
140	    }
141#endif
142	default:
143#ifdef DEBUG
144		printf("in6_gif_output: warning: unknown family %d passed\n",
145			family);
146#endif
147		m_freem(m);
148		return EAFNOSUPPORT;
149	}
150
151	/* prepend new IP header */
152	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
153	if (m && m->m_len < sizeof(struct ip6_hdr))
154		m = m_pullup(m, sizeof(struct ip6_hdr));
155	if (m == NULL)
156		return ENOBUFS;
157
158	ip6 = mtod(m, struct ip6_hdr *);
159	ip6->ip6_flow	= 0;
160	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
161	ip6->ip6_vfc	|= IPV6_VERSION;
162#if 0	/* ip6->ip6_plen will be filled by ip6_output */
163	ip6->ip6_plen	= htons((u_int16_t)m->m_pkthdr.len);
164#endif
165	ip6->ip6_nxt	= proto;
166	ip6->ip6_hlim	= ip6_gif_hlim;
167	ip6->ip6_src	= sin6_src->sin6_addr;
168	/* bidirectional configured tunnel mode */
169	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
170		ip6->ip6_dst = sin6_dst->sin6_addr;
171	else  {
172		m_freem(m);
173		return ENETUNREACH;
174	}
175	if (ifp->if_flags & IFF_LINK1)
176		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
177	else
178		ip_ecn_ingress(ECN_NOCARE, &otos, &itos);
179	ip6->ip6_flow &= ~ntohl(0xff00000);
180	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
181
182	sc = ifp->if_softc;
183	if_tunnel_get_ro(sc->gif_ro_percpu, &ro_pc, &lock_pc);
184	rt = rtcache_lookup(ro_pc, var->gv_pdst);
185	if (rt == NULL) {
186		if_tunnel_put_ro(sc->gif_ro_percpu, lock_pc);
187		m_freem(m);
188		return ENETUNREACH;
189	}
190
191	/* If the route constitutes infinite encapsulation, punt. */
192	if (rt->rt_ifp == ifp) {
193		rtcache_unref(rt, ro_pc);
194		rtcache_free(ro_pc);
195		if_tunnel_put_ro(sc->gif_ro_percpu, lock_pc);
196		m_freem(m);
197		return ENETUNREACH;	/* XXX */
198	}
199	rtcache_unref(rt, ro_pc);
200
201#ifdef IPV6_MINMTU
202	int flags;
203
204	/*
205	 * - GIF_PMTU_MINMTU
206	 *   Force fragmentation to minimum MTU to avoid path MTU discovery
207	 * - GIF_PMTU_OUTERMTU
208	 *   Trust outer MTU is large enough to send all packets
209	 *
210	 * It is too painful to ask for resend of inner packet, to achieve
211	 * path MTU discovery for encapsulated packets.
212	 *
213	 * See RFC4459.
214	 */
215	if (sc->gif_pmtu == GIF_PMTU_SYSDEFAULT) {
216		switch (ip6_gif_pmtu) {
217		case GIF_PMTU_MINMTU:
218			flags = IPV6_MINMTU;
219			break;
220		case GIF_PMTU_OUTERMTU:
221			flags = 0;
222			break;
223		default:
224#ifdef DEBUG
225			log(LOG_DEBUG, "%s: ignore unexpected ip6_gif_pmtu %d\n",
226			    __func__, ip6_gif_pmtu);
227#endif
228			flags = IPV6_MINMTU;
229			break;
230		}
231	} else {
232		switch (sc->gif_pmtu) {
233		case GIF_PMTU_MINMTU:
234			flags = IPV6_MINMTU;
235			break;
236		case GIF_PMTU_OUTERMTU:
237			flags = 0;
238			break;
239		default:
240#ifdef DEBUG
241			log(LOG_DEBUG, "%s: ignore unexpected gif_pmtu of %s %d\n",
242			    __func__, ifp->if_xname, sc->gif_pmtu);
243#endif
244			flags = IPV6_MINMTU;
245			break;
246		}
247	}
248
249	error = ip6_output(m, 0, ro_pc, flags, NULL, NULL, NULL);
250#else
251	error = ip6_output(m, 0, ro_pc, 0, NULL, NULL, NULL);
252#endif
253	if_tunnel_put_ro(sc->gif_ro_percpu, lock_pc);
254	return (error);
255}
256
257int
258in6_gif_input(struct mbuf **mp, int *offp, int proto, void *eparg)
259{
260	struct mbuf *m = *mp;
261	struct gif_softc *sc = eparg;
262	struct ifnet *gifp;
263	struct ip6_hdr *ip6;
264	int af = 0;
265	u_int32_t otos;
266
267	KASSERT(sc != NULL);
268
269	ip6 = mtod(m, struct ip6_hdr *);
270
271	gifp = &sc->gif_if;
272	if ((gifp->if_flags & IFF_UP) == 0) {
273		m_freem(m);
274		IP6_STATINC(IP6_STAT_NOGIF);
275		return IPPROTO_DONE;
276	}
277#ifndef GIF_ENCAPCHECK
278	struct psref psref_var;
279	struct gif_variant *var = gif_getref_variant(sc, &psref_var);
280	/* other CPU do delete_tunnel */
281	if (var->gv_psrc == NULL || var->gv_pdst == NULL) {
282		gif_putref_variant(var, &psref_var);
283		m_freem(m);
284		IP6_STATINC(IP6_STAT_NOGIF);
285		return IPPROTO_DONE;
286	}
287
288	struct psref psref;
289	struct ifnet *rcvif = m_get_rcvif_psref(m, &psref);
290	if (rcvif == NULL || !gif_validate6(ip6, var, rcvif)) {
291		m_put_rcvif_psref(rcvif, &psref);
292		gif_putref_variant(var, &psref_var);
293		m_freem(m);
294		IP6_STATINC(IP6_STAT_NOGIF);
295		return IPPROTO_DONE;
296	}
297	m_put_rcvif_psref(rcvif, &psref);
298	gif_putref_variant(var, &psref_var);
299#endif
300
301	otos = ip6->ip6_flow;
302	m_adj(m, *offp);
303
304	switch (proto) {
305#ifdef INET
306	case IPPROTO_IPV4:
307	    {
308		struct ip *ip;
309		u_int8_t otos8;
310		af = AF_INET;
311		otos8 = (ntohl(otos) >> 20) & 0xff;
312		if (m->m_len < sizeof(*ip)) {
313			m = m_pullup(m, sizeof(*ip));
314			if (!m)
315				return IPPROTO_DONE;
316		}
317		ip = mtod(m, struct ip *);
318		if (gifp->if_flags & IFF_LINK1)
319			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
320		else
321			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
322		break;
323	    }
324#endif /* INET */
325#ifdef INET6
326	case IPPROTO_IPV6:
327	    {
328		struct ip6_hdr *ip6x;
329		af = AF_INET6;
330		if (m->m_len < sizeof(*ip6x)) {
331			m = m_pullup(m, sizeof(*ip6x));
332			if (!m)
333				return IPPROTO_DONE;
334		}
335		ip6x = mtod(m, struct ip6_hdr *);
336		if (gifp->if_flags & IFF_LINK1)
337			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6x->ip6_flow);
338		else
339			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6x->ip6_flow);
340		break;
341	    }
342#endif
343	default:
344		IP6_STATINC(IP6_STAT_NOGIF);
345		m_freem(m);
346		return IPPROTO_DONE;
347	}
348
349	gif_input(m, af, gifp);
350	return IPPROTO_DONE;
351}
352
353/*
354 * validate outer address.
355 */
356static int
357gif_validate6(const struct ip6_hdr *ip6, struct gif_variant *var,
358	struct ifnet *ifp)
359{
360	const struct sockaddr_in6 *src, *dst;
361	int ret;
362
363	src = satosin6(var->gv_psrc);
364	dst = satosin6(var->gv_pdst);
365
366	ret = in6_tunnel_validate(ip6, &src->sin6_addr, &dst->sin6_addr);
367	if (ret == 0)
368		return 0;
369
370	/* ingress filters on outer source */
371	if ((var->gv_softc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
372		union {
373			struct sockaddr sa;
374			struct sockaddr_in6 sin6;
375		} u;
376		struct rtentry *rt;
377
378		/* XXX scopeid */
379		sockaddr_in6_init(&u.sin6, &ip6->ip6_src, 0, 0, 0);
380		rt = rtalloc1(&u.sa, 0);
381		if (rt == NULL || rt->rt_ifp != ifp) {
382#if 0
383			char ip6buf[INET6_ADDRSTRLEN];
384			log(LOG_WARNING, "%s: packet from %s dropped "
385			    "due to ingress filter\n",
386			    if_name(&var->gv_softc->gif_if),
387			    IN6_PRINT(ip6buf, &u.sin6.sin6_addr));
388#endif
389			if (rt != NULL)
390				rt_unref(rt);
391			return 0;
392		}
393		rt_unref(rt);
394	}
395
396	return ret;
397}
398
399#ifdef GIF_ENCAPCHECK
400/*
401 * we know that we are in IFF_UP, outer address available, and outer family
402 * matched the physical addr family.  see gif_encapcheck().
403 */
404int
405gif_encapcheck6(struct mbuf *m, int off, int proto, struct gif_variant *var)
406{
407	struct ip6_hdr ip6;
408	struct ifnet *ifp = NULL;
409	int r;
410	struct psref psref;
411
412	m_copydata(m, 0, sizeof(ip6), (void *)&ip6);
413	if ((m->m_flags & M_PKTHDR) != 0)
414		ifp = m_get_rcvif_psref(m, &psref);
415
416	r = gif_validate6(&ip6, var, ifp);
417
418	m_put_rcvif_psref(ifp, &psref);
419	return r;
420}
421#endif
422
423int
424in6_gif_attach(struct gif_variant *var)
425{
426#ifndef GIF_ENCAPCHECK
427	struct sockaddr_in6 mask6;
428
429	memset(&mask6, 0, sizeof(mask6));
430	mask6.sin6_len = sizeof(struct sockaddr_in6);
431	mask6.sin6_addr.s6_addr32[0] = mask6.sin6_addr.s6_addr32[1] =
432	    mask6.sin6_addr.s6_addr32[2] = mask6.sin6_addr.s6_addr32[3] = ~0;
433
434	if (!var->gv_psrc || !var->gv_pdst)
435		return EINVAL;
436
437	var->gv_encap_cookie6 = encap_attach_addr(AF_INET6, -1, var->gv_psrc,
438	    var->gv_pdst, NULL, &in6_gif_encapsw, var->gv_softc);
439#else
440	var->gv_encap_cookie6 = encap_attach_addr(AF_INET6, -1, var->gv_psrc,
441	    var->gv_pdst, gif_encapcheck, &in6_gif_encapsw, var->gv_softc);
442#endif
443	if (var->gv_encap_cookie6 == NULL)
444		return EEXIST;
445
446	var->gv_output = in6_gif_output;
447	return 0;
448}
449
450int
451in6_gif_detach(struct gif_variant *var)
452{
453	int error;
454	struct gif_softc *sc = var->gv_softc;
455
456	error = encap_detach(var->gv_encap_cookie6);
457	if (error == 0)
458		var->gv_encap_cookie6 = NULL;
459
460	if_tunnel_ro_percpu_rtcache_free(sc->gif_ro_percpu);
461
462	return error;
463}
464
465void *
466in6_gif_ctlinput(int cmd, const struct sockaddr *sa, void *d, void *eparg)
467{
468	struct gif_softc *sc = eparg;
469	struct gif_variant *var;
470	struct ip6ctlparam *ip6cp = NULL;
471	struct ip6_hdr *ip6;
472	const struct sockaddr_in6 *dst6;
473	struct route *ro_pc;
474	kmutex_t *lock_pc;
475	struct psref psref;
476
477	if (sa->sa_family != AF_INET6 ||
478	    sa->sa_len != sizeof(struct sockaddr_in6))
479		return NULL;
480
481	if ((unsigned)cmd >= PRC_NCMDS)
482		return NULL;
483	if (cmd == PRC_HOSTDEAD)
484		d = NULL;
485	else if (inet6ctlerrmap[cmd] == 0)
486		return NULL;
487
488	/* if the parameter is from icmp6, decode it. */
489	if (d != NULL) {
490		ip6cp = (struct ip6ctlparam *)d;
491		ip6 = ip6cp->ip6c_ip6;
492	} else {
493		ip6 = NULL;
494	}
495
496	if (!ip6)
497		return NULL;
498
499	var = gif_getref_variant(sc, &psref);
500	if (var->gv_psrc == NULL || var->gv_pdst == NULL) {
501		gif_putref_variant(var, &psref);
502		return NULL;
503	}
504	if (var->gv_psrc->sa_family != AF_INET6) {
505		gif_putref_variant(var, &psref);
506		return NULL;
507	}
508	gif_putref_variant(var, &psref);
509
510	if_tunnel_get_ro(sc->gif_ro_percpu, &ro_pc, &lock_pc);
511	dst6 = satocsin6(rtcache_getdst(ro_pc));
512	/* XXX scope */
513	if (dst6 == NULL)
514		;
515	else if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst6->sin6_addr))
516		rtcache_free(ro_pc);
517
518	if_tunnel_put_ro(sc->gif_ro_percpu, lock_pc);
519	return NULL;
520}
521
522ENCAP_PR_WRAP_CTLINPUT(in6_gif_ctlinput)
523#define	in6_gif_ctlinput	in6_gif_ctlinput_wrapper
524
525static const struct encapsw in6_gif_encapsw = {
526	.encapsw6 = {
527		.pr_input	= in6_gif_input,
528		.pr_ctlinput	= in6_gif_ctlinput,
529	}
530};
531