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in_gif.c revision 1.25 
      1 /*	$NetBSD: in_gif.c,v 1.25 2001/11/13 00:32:36 lukem Exp $	*/
      2 /*	$KAME: in_gif.c,v 1.66 2001/07/29 04:46:09 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: in_gif.c,v 1.25 2001/11/13 00:32:36 lukem Exp $");
     35 
     36 #include "opt_inet.h"
     37 #include "opt_iso.h"
     38 
     39 /* define it if you want to use encap_attach_func (it helps *BSD merge) */
     40 #define USE_ENCAPCHECK
     41 
     42 #include <sys/param.h>
     43 #include <sys/systm.h>
     44 #include <sys/socket.h>
     45 #include <sys/sockio.h>
     46 #include <sys/mbuf.h>
     47 #include <sys/errno.h>
     48 #include <sys/ioctl.h>
     49 #include <sys/syslog.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 #include <netinet/ip.h>
     57 #include <netinet/ip_var.h>
     58 #include <netinet/in_gif.h>
     59 #include <netinet/in_var.h>
     60 #include <netinet/ip_encap.h>
     61 #include <netinet/ip_ecn.h>
     62 
     63 #ifdef INET6
     64 #include <netinet/ip6.h>
     65 #endif
     66 
     67 #include <net/if_gif.h>
     68 
     69 #include "gif.h"
     70 
     71 #include <machine/stdarg.h>
     72 
     73 #include <net/net_osdep.h>
     74 
     75 static int gif_validate4 __P((const struct ip *, struct gif_softc *,
     76 	struct ifnet *));
     77 
     78 #if NGIF > 0
     79 int ip_gif_ttl = GIF_TTL;
     80 #else
     81 int ip_gif_ttl = 0;
     82 #endif
     83 
     84 extern struct protosw in_gif_protosw;
     85 
     86 int
     87 in_gif_output(ifp, family, m)
     88 	struct ifnet	*ifp;
     89 	int		family;
     90 	struct mbuf	*m;
     91 {
     92 	struct gif_softc *sc = (struct gif_softc*)ifp;
     93 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
     94 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
     95 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
     96 	struct ip iphdr;	/* capsule IP header, host byte ordered */
     97 	int proto, error;
     98 	u_int8_t tos;
     99 
    100 	if (sin_src == NULL || sin_dst == NULL ||
    101 	    sin_src->sin_family != AF_INET ||
    102 	    sin_dst->sin_family != AF_INET) {
    103 		m_freem(m);
    104 		return EAFNOSUPPORT;
    105 	}
    106 
    107 	switch (family) {
    108 #ifdef INET
    109 	case AF_INET:
    110 	    {
    111 		struct ip *ip;
    112 
    113 		proto = IPPROTO_IPV4;
    114 		if (m->m_len < sizeof(*ip)) {
    115 			m = m_pullup(m, sizeof(*ip));
    116 			if (!m)
    117 				return ENOBUFS;
    118 		}
    119 		ip = mtod(m, struct ip *);
    120 		tos = ip->ip_tos;
    121 		break;
    122 	    }
    123 #endif /*INET*/
    124 #ifdef INET6
    125 	case AF_INET6:
    126 	    {
    127 		struct ip6_hdr *ip6;
    128 		proto = IPPROTO_IPV6;
    129 		if (m->m_len < sizeof(*ip6)) {
    130 			m = m_pullup(m, sizeof(*ip6));
    131 			if (!m)
    132 				return ENOBUFS;
    133 		}
    134 		ip6 = mtod(m, struct ip6_hdr *);
    135 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
    136 		break;
    137 	    }
    138 #endif /*INET6*/
    139 #ifdef ISO
    140 	case AF_ISO:
    141 		proto = IPPROTO_EON;
    142 		tos = 0;
    143 		break;
    144 #endif
    145 	default:
    146 #ifdef DEBUG
    147 		printf("in_gif_output: warning: unknown family %d passed\n",
    148 			family);
    149 #endif
    150 		m_freem(m);
    151 		return EAFNOSUPPORT;
    152 	}
    153 
    154 	bzero(&iphdr, sizeof(iphdr));
    155 	iphdr.ip_src = sin_src->sin_addr;
    156 	/* bidirectional configured tunnel mode */
    157 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
    158 		iphdr.ip_dst = sin_dst->sin_addr;
    159 	else {
    160 		m_freem(m);
    161 		return ENETUNREACH;
    162 	}
    163 	iphdr.ip_p = proto;
    164 	/* version will be set in ip_output() */
    165 	iphdr.ip_ttl = ip_gif_ttl;
    166 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
    167 	if (ifp->if_flags & IFF_LINK1)
    168 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
    169 	else
    170 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
    171 
    172 	/* prepend new IP header */
    173 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
    174 	if (m && m->m_len < sizeof(struct ip))
    175 		m = m_pullup(m, sizeof(struct ip));
    176 	if (m == NULL)
    177 		return ENOBUFS;
    178 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
    179 
    180 	if (dst->sin_family != sin_dst->sin_family ||
    181 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
    182 		/* cache route doesn't match */
    183 		dst->sin_family = sin_dst->sin_family;
    184 		dst->sin_len = sizeof(struct sockaddr_in);
    185 		dst->sin_addr = sin_dst->sin_addr;
    186 		if (sc->gif_ro.ro_rt) {
    187 			RTFREE(sc->gif_ro.ro_rt);
    188 			sc->gif_ro.ro_rt = NULL;
    189 		}
    190 	}
    191 
    192 	if (sc->gif_ro.ro_rt == NULL) {
    193 		rtalloc(&sc->gif_ro);
    194 		if (sc->gif_ro.ro_rt == NULL) {
    195 			m_freem(m);
    196 			return ENETUNREACH;
    197 		}
    198 
    199 		/* if it constitutes infinite encapsulation, punt. */
    200 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
    201 			m_freem(m);
    202 			return ENETUNREACH;	/*XXX*/
    203 		}
    204 	}
    205 
    206 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL);
    207 	return(error);
    208 }
    209 
    210 void
    211 #if __STDC__
    212 in_gif_input(struct mbuf *m, ...)
    213 #else
    214 in_gif_input(m, va_alist)
    215 	struct mbuf *m;
    216 	va_dcl
    217 #endif
    218 {
    219 	int off, proto;
    220 	struct ifnet *gifp = NULL;
    221 	struct ip *ip;
    222 	va_list ap;
    223 	int af;
    224 	u_int8_t otos;
    225 
    226 	va_start(ap, m);
    227 	off = va_arg(ap, int);
    228 	proto = va_arg(ap, int);
    229 	va_end(ap);
    230 
    231 	ip = mtod(m, struct ip *);
    232 
    233 	gifp = (struct ifnet *)encap_getarg(m);
    234 
    235 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
    236 		m_freem(m);
    237 		ipstat.ips_nogif++;
    238 		return;
    239 	}
    240 #ifndef USE_ENCAPCHECK
    241 	if (!gif_validate4(ip, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
    242 		m_freem(m);
    243 		ipstat.ips_nogif++;
    244 		return;
    245 	}
    246 #endif
    247 
    248 	otos = ip->ip_tos;
    249 	m_adj(m, off);
    250 
    251 	switch (proto) {
    252 #ifdef INET
    253 	case IPPROTO_IPV4:
    254 	    {
    255 		struct ip *ip;
    256 		af = AF_INET;
    257 		if (m->m_len < sizeof(*ip)) {
    258 			m = m_pullup(m, sizeof(*ip));
    259 			if (!m)
    260 				return;
    261 		}
    262 		ip = mtod(m, struct ip *);
    263 		if (gifp->if_flags & IFF_LINK1)
    264 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
    265 		else
    266 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
    267 		break;
    268 	    }
    269 #endif
    270 #ifdef INET6
    271 	case IPPROTO_IPV6:
    272 	    {
    273 		struct ip6_hdr *ip6;
    274 		u_int8_t itos;
    275 		af = AF_INET6;
    276 		if (m->m_len < sizeof(*ip6)) {
    277 			m = m_pullup(m, sizeof(*ip6));
    278 			if (!m)
    279 				return;
    280 		}
    281 		ip6 = mtod(m, struct ip6_hdr *);
    282 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
    283 		if (gifp->if_flags & IFF_LINK1)
    284 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
    285 		else
    286 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
    287 		ip6->ip6_flow &= ~htonl(0xff << 20);
    288 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
    289 		break;
    290 	    }
    291 #endif /* INET6 */
    292 #ifdef ISO
    293 	case IPPROTO_EON:
    294 		af = AF_ISO;
    295 		break;
    296 #endif
    297 	default:
    298 		ipstat.ips_nogif++;
    299 		m_freem(m);
    300 		return;
    301 	}
    302 	gif_input(m, af, gifp);
    303 	return;
    304 }
    305 
    306 /*
    307  * validate outer address.
    308  */
    309 static int
    310 gif_validate4(ip, sc, ifp)
    311 	const struct ip *ip;
    312 	struct gif_softc *sc;
    313 	struct ifnet *ifp;
    314 {
    315 	struct sockaddr_in *src, *dst;
    316 	struct in_ifaddr *ia4;
    317 
    318 	src = (struct sockaddr_in *)sc->gif_psrc;
    319 	dst = (struct sockaddr_in *)sc->gif_pdst;
    320 
    321 	/* check for address match */
    322 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
    323 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
    324 		return 0;
    325 
    326 	/* martian filters on outer source - NOT done in ip_input! */
    327 	if (IN_MULTICAST(ip->ip_src.s_addr))
    328 		return 0;
    329 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
    330 	case 0: case 127: case 255:
    331 		return 0;
    332 	}
    333 	/* reject packets with broadcast on source */
    334 	TAILQ_FOREACH(ia4, &in_ifaddr, ia_list) {
    335 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
    336 			continue;
    337 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
    338 			return 0;
    339 	}
    340 
    341 	/* ingress filters on outer source */
    342 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
    343 		struct sockaddr_in sin;
    344 		struct rtentry *rt;
    345 
    346 		bzero(&sin, sizeof(sin));
    347 		sin.sin_family = AF_INET;
    348 		sin.sin_len = sizeof(struct sockaddr_in);
    349 		sin.sin_addr = ip->ip_src;
    350 		rt = rtalloc1((struct sockaddr *)&sin, 0);
    351 		if (!rt || rt->rt_ifp != ifp) {
    352 #if 0
    353 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
    354 			    "due to ingress filter\n", if_name(&sc->gif_if),
    355 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
    356 #endif
    357 			if (rt)
    358 				rtfree(rt);
    359 			return 0;
    360 		}
    361 		rtfree(rt);
    362 	}
    363 
    364 	return 32 * 2;
    365 }
    366 
    367 /*
    368  * we know that we are in IFF_UP, outer address available, and outer family
    369  * matched the physical addr family.  see gif_encapcheck().
    370  */
    371 int
    372 gif_encapcheck4(m, off, proto, arg)
    373 	const struct mbuf *m;
    374 	int off;
    375 	int proto;
    376 	void *arg;
    377 {
    378 	struct ip ip;
    379 	struct gif_softc *sc;
    380 	struct ifnet *ifp;
    381 
    382 	/* sanity check done in caller */
    383 	sc = (struct gif_softc *)arg;
    384 
    385 	/* LINTED const cast */
    386 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
    387 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
    388 
    389 	return gif_validate4(&ip, sc, ifp);
    390 }
    391 
    392 int
    393 in_gif_attach(sc)
    394 	struct gif_softc *sc;
    395 {
    396 #ifndef USE_ENCAPCHECK
    397 	struct sockaddr_in mask4;
    398 
    399 	bzero(&mask4, sizeof(mask4));
    400 	mask4.sin_len = sizeof(struct sockaddr_in);
    401 	mask4.sin_addr.s_addr = ~0;
    402 
    403 	if (!sc->gif_psrc || !sc->gif_pdst)
    404 		return EINVAL;
    405 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
    406 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
    407 	    (struct protosw *)&in_gif_protosw, sc);
    408 #else
    409 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
    410 	    &in_gif_protosw, sc);
    411 #endif
    412 	if (sc->encap_cookie4 == NULL)
    413 		return EEXIST;
    414 	return 0;
    415 }
    416 
    417 int
    418 in_gif_detach(sc)
    419 	struct gif_softc *sc;
    420 {
    421 	int error;
    422 
    423 	error = encap_detach(sc->encap_cookie4);
    424 	if (error == 0)
    425 		sc->encap_cookie4 = NULL;
    426 	return error;
    427 }
    428