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in_gif.c revision 1.35 
      1 /*	$NetBSD: in_gif.c,v 1.35 2004/04/22 01:01:41 matt 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 1.35 2004/04/22 01:01:41 matt Exp $");
     35 
     36 #include "opt_inet.h"
     37 #include "opt_iso.h"
     38 
     39 #include <sys/param.h>
     40 #include <sys/systm.h>
     41 #include <sys/socket.h>
     42 #include <sys/sockio.h>
     43 #include <sys/mbuf.h>
     44 #include <sys/errno.h>
     45 #include <sys/ioctl.h>
     46 #include <sys/syslog.h>
     47 #include <sys/protosw.h>
     48 
     49 #include <net/if.h>
     50 #include <net/route.h>
     51 
     52 #include <netinet/in.h>
     53 #include <netinet/in_systm.h>
     54 #include <netinet/ip.h>
     55 #include <netinet/ip_var.h>
     56 #include <netinet/in_gif.h>
     57 #include <netinet/in_var.h>
     58 #include <netinet/ip_encap.h>
     59 #include <netinet/ip_ecn.h>
     60 
     61 #ifdef INET6
     62 #include <netinet/ip6.h>
     63 #endif
     64 
     65 #include <net/if_gif.h>
     66 
     67 #include "gif.h"
     68 
     69 #include <machine/stdarg.h>
     70 
     71 #include <net/net_osdep.h>
     72 
     73 static int gif_validate4 __P((const struct ip *, struct gif_softc *,
     74 	struct ifnet *));
     75 
     76 #if NGIF > 0
     77 int ip_gif_ttl = GIF_TTL;
     78 #else
     79 int ip_gif_ttl = 0;
     80 #endif
     81 
     82 const struct protosw in_gif_protosw =
     83 { SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
     84   in_gif_input, rip_output,	0,		rip_ctloutput,
     85   rip_usrreq,
     86   0,            0,              0,              0,
     87 };
     88 
     89 int
     90 in_gif_output(ifp, family, m)
     91 	struct ifnet	*ifp;
     92 	int		family;
     93 	struct mbuf	*m;
     94 {
     95 	struct gif_softc *sc = (struct gif_softc*)ifp;
     96 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
     97 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
     98 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
     99 	struct ip iphdr;	/* capsule IP header, host byte ordered */
    100 	int proto, error;
    101 	u_int8_t tos;
    102 
    103 	if (sin_src == NULL || sin_dst == NULL ||
    104 	    sin_src->sin_family != AF_INET ||
    105 	    sin_dst->sin_family != AF_INET) {
    106 		m_freem(m);
    107 		return EAFNOSUPPORT;
    108 	}
    109 
    110 	switch (family) {
    111 #ifdef INET
    112 	case AF_INET:
    113 	    {
    114 		struct ip *ip;
    115 
    116 		proto = IPPROTO_IPV4;
    117 		if (m->m_len < sizeof(*ip)) {
    118 			m = m_pullup(m, sizeof(*ip));
    119 			if (!m)
    120 				return ENOBUFS;
    121 		}
    122 		ip = mtod(m, struct ip *);
    123 		tos = ip->ip_tos;
    124 		break;
    125 	    }
    126 #endif /* INET */
    127 #ifdef INET6
    128 	case AF_INET6:
    129 	    {
    130 		struct ip6_hdr *ip6;
    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 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
    139 		break;
    140 	    }
    141 #endif /* INET6 */
    142 #ifdef ISO
    143 	case AF_ISO:
    144 		proto = IPPROTO_EON;
    145 		tos = 0;
    146 		break;
    147 #endif
    148 	default:
    149 #ifdef DEBUG
    150 		printf("in_gif_output: warning: unknown family %d passed\n",
    151 			family);
    152 #endif
    153 		m_freem(m);
    154 		return EAFNOSUPPORT;
    155 	}
    156 
    157 	bzero(&iphdr, sizeof(iphdr));
    158 	iphdr.ip_src = sin_src->sin_addr;
    159 	/* bidirectional configured tunnel mode */
    160 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
    161 		iphdr.ip_dst = sin_dst->sin_addr;
    162 	else {
    163 		m_freem(m);
    164 		return ENETUNREACH;
    165 	}
    166 	iphdr.ip_p = proto;
    167 	/* version will be set in ip_output() */
    168 	iphdr.ip_ttl = ip_gif_ttl;
    169 	iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
    170 	if (ifp->if_flags & IFF_LINK1)
    171 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
    172 	else
    173 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
    174 
    175 	/* prepend new IP header */
    176 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
    177 	if (m && m->m_len < sizeof(struct ip))
    178 		m = m_pullup(m, sizeof(struct ip));
    179 	if (m == NULL)
    180 		return ENOBUFS;
    181 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
    182 
    183 	if (dst->sin_family != sin_dst->sin_family ||
    184 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
    185 		/* cache route doesn't match */
    186 		bzero(dst, sizeof(*dst));
    187 		dst->sin_family = sin_dst->sin_family;
    188 		dst->sin_len = sizeof(struct sockaddr_in);
    189 		dst->sin_addr = sin_dst->sin_addr;
    190 		if (sc->gif_ro.ro_rt) {
    191 			RTFREE(sc->gif_ro.ro_rt);
    192 			sc->gif_ro.ro_rt = NULL;
    193 		}
    194 	}
    195 
    196 	if (sc->gif_ro.ro_rt == NULL) {
    197 		rtalloc(&sc->gif_ro);
    198 		if (sc->gif_ro.ro_rt == NULL) {
    199 			m_freem(m);
    200 			return ENETUNREACH;
    201 		}
    202 
    203 		/* if it constitutes infinite encapsulation, punt. */
    204 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
    205 			m_freem(m);
    206 			return ENETUNREACH;	/*XXX*/
    207 		}
    208 	}
    209 
    210 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
    211 	return (error);
    212 }
    213 
    214 void
    215 #if __STDC__
    216 in_gif_input(struct mbuf *m, ...)
    217 #else
    218 in_gif_input(m, va_alist)
    219 	struct mbuf *m;
    220 	va_dcl
    221 #endif
    222 {
    223 	int off, proto;
    224 	struct ifnet *gifp = NULL;
    225 	struct ip *ip;
    226 	va_list ap;
    227 	int af;
    228 	u_int8_t otos;
    229 
    230 	va_start(ap, m);
    231 	off = va_arg(ap, int);
    232 	proto = va_arg(ap, int);
    233 	va_end(ap);
    234 
    235 	ip = mtod(m, struct ip *);
    236 
    237 	gifp = (struct ifnet *)encap_getarg(m);
    238 
    239 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
    240 		m_freem(m);
    241 		ipstat.ips_nogif++;
    242 		return;
    243 	}
    244 #ifndef GIF_ENCAPCHECK
    245 	if (!gif_validate4(ip, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
    246 		m_freem(m);
    247 		ipstat.ips_nogif++;
    248 		return;
    249 	}
    250 #endif
    251 
    252 	otos = ip->ip_tos;
    253 	m_adj(m, off);
    254 
    255 	switch (proto) {
    256 #ifdef INET
    257 	case IPPROTO_IPV4:
    258 	    {
    259 		struct ip *ip;
    260 		af = AF_INET;
    261 		if (m->m_len < sizeof(*ip)) {
    262 			m = m_pullup(m, sizeof(*ip));
    263 			if (!m)
    264 				return;
    265 		}
    266 		ip = mtod(m, struct ip *);
    267 		if (gifp->if_flags & IFF_LINK1)
    268 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
    269 		else
    270 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
    271 		break;
    272 	    }
    273 #endif
    274 #ifdef INET6
    275 	case IPPROTO_IPV6:
    276 	    {
    277 		struct ip6_hdr *ip6;
    278 		u_int8_t itos;
    279 		af = AF_INET6;
    280 		if (m->m_len < sizeof(*ip6)) {
    281 			m = m_pullup(m, sizeof(*ip6));
    282 			if (!m)
    283 				return;
    284 		}
    285 		ip6 = mtod(m, struct ip6_hdr *);
    286 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
    287 		if (gifp->if_flags & IFF_LINK1)
    288 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
    289 		else
    290 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
    291 		ip6->ip6_flow &= ~htonl(0xff << 20);
    292 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
    293 		break;
    294 	    }
    295 #endif /* INET6 */
    296 #ifdef ISO
    297 	case IPPROTO_EON:
    298 		af = AF_ISO;
    299 		break;
    300 #endif
    301 	default:
    302 		ipstat.ips_nogif++;
    303 		m_freem(m);
    304 		return;
    305 	}
    306 	gif_input(m, af, gifp);
    307 	return;
    308 }
    309 
    310 /*
    311  * validate outer address.
    312  */
    313 static int
    314 gif_validate4(ip, sc, ifp)
    315 	const struct ip *ip;
    316 	struct gif_softc *sc;
    317 	struct ifnet *ifp;
    318 {
    319 	struct sockaddr_in *src, *dst;
    320 	struct in_ifaddr *ia4;
    321 
    322 	src = (struct sockaddr_in *)sc->gif_psrc;
    323 	dst = (struct sockaddr_in *)sc->gif_pdst;
    324 
    325 	/* check for address match */
    326 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
    327 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
    328 		return 0;
    329 
    330 	/* martian filters on outer source - NOT done in ip_input! */
    331 	if (IN_MULTICAST(ip->ip_src.s_addr))
    332 		return 0;
    333 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
    334 	case 0: case 127: case 255:
    335 		return 0;
    336 	}
    337 	/* reject packets with broadcast on source */
    338 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
    339 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
    340 			continue;
    341 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
    342 			return 0;
    343 	}
    344 
    345 	/* ingress filters on outer source */
    346 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
    347 		struct sockaddr_in sin;
    348 		struct rtentry *rt;
    349 
    350 		bzero(&sin, sizeof(sin));
    351 		sin.sin_family = AF_INET;
    352 		sin.sin_len = sizeof(struct sockaddr_in);
    353 		sin.sin_addr = ip->ip_src;
    354 		rt = rtalloc1((struct sockaddr *)&sin, 0);
    355 		if (!rt || rt->rt_ifp != ifp) {
    356 #if 0
    357 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
    358 			    "due to ingress filter\n", if_name(&sc->gif_if),
    359 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
    360 #endif
    361 			if (rt)
    362 				rtfree(rt);
    363 			return 0;
    364 		}
    365 		rtfree(rt);
    366 	}
    367 
    368 	return 32 * 2;
    369 }
    370 
    371 #ifdef GIF_ENCAPCHECK
    372 /*
    373  * we know that we are in IFF_UP, outer address available, and outer family
    374  * matched the physical addr family.  see gif_encapcheck().
    375  */
    376 int
    377 gif_encapcheck4(m, off, proto, arg)
    378 	const struct mbuf *m;
    379 	int off;
    380 	int proto;
    381 	void *arg;
    382 {
    383 	struct ip ip;
    384 	struct gif_softc *sc;
    385 	struct ifnet *ifp;
    386 
    387 	/* sanity check done in caller */
    388 	sc = (struct gif_softc *)arg;
    389 
    390 	/* LINTED const cast */
    391 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
    392 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
    393 
    394 	return gif_validate4(&ip, sc, ifp);
    395 }
    396 #endif
    397 
    398 int
    399 in_gif_attach(sc)
    400 	struct gif_softc *sc;
    401 {
    402 #ifndef GIF_ENCAPCHECK
    403 	struct sockaddr_in mask4;
    404 
    405 	bzero(&mask4, sizeof(mask4));
    406 	mask4.sin_len = sizeof(struct sockaddr_in);
    407 	mask4.sin_addr.s_addr = ~0;
    408 
    409 	if (!sc->gif_psrc || !sc->gif_pdst)
    410 		return EINVAL;
    411 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
    412 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
    413 	    (struct protosw *)&in_gif_protosw, sc);
    414 #else
    415 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
    416 	    &in_gif_protosw, sc);
    417 #endif
    418 	if (sc->encap_cookie4 == NULL)
    419 		return EEXIST;
    420 	return 0;
    421 }
    422 
    423 int
    424 in_gif_detach(sc)
    425 	struct gif_softc *sc;
    426 {
    427 	int error;
    428 
    429 	error = encap_detach(sc->encap_cookie4);
    430 	if (error == 0)
    431 		sc->encap_cookie4 = NULL;
    432 	return error;
    433 }
    434