sys/netinet6/ip6_etherip.c

   1 /*      $NetBSD: ip6_etherip.c,v 1.10 2008/10/16 18:56:56 hans Exp $        */
   2
   3 /*
   4  *  Copyright (c) 2006, Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
   5  *  All rights reserved.
   6  *
   7  *  Redistribution and use in source and binary forms, with or without
   8  *  modification, are permitted provided that the following conditions
   9  *  are met:
  10  *  1. Redistributions of source code must retain the above copyright
  11  *     notice, this list of conditions and the following disclaimer.
  12  *  2. Redistributions in binary form must reproduce the above copyright
  13  *     notice, this list of conditions and the following disclaimer in the
  14  *     documentation and/or other materials provided with the distribution.
  15  *  3. Neither the name of Hans Rosenfeld nor the names of his
  16  *     contributors may be used to endorse or promote products derived
  17  *     from this software without specific prior written permission.
  18  *
  19  *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  *  SUCH DAMAGE.
  30  *
  31  *
  32  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  33  * All rights reserved.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. Neither the name of the project nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  */
  59
  60 #include <sys/cdefs.h>
  61 __KERNEL_RCSID(0, "$NetBSD: ip6_etherip.c,v 1.10 2008/10/16 18:56:56 hans Exp $");
  62
  63 #include "opt_inet.h"
  64 #include "bpfilter.h"
  65
  66 #include <sys/param.h>
  67 #include <sys/systm.h>
  68 #include <sys/socket.h>
  69 #include <sys/sockio.h>
  70 #include <sys/mbuf.h>
  71 #include <sys/device.h>
  72 #include <sys/errno.h>
  73 #include <sys/ioctl.h>
  74 #include <sys/syslog.h>
  75 #include <sys/protosw.h>
  76 #include <sys/kernel.h>
  77
  78 #include <net/if.h>
  79 #include <net/route.h>
  80
  81 #include <netinet/in.h>
  82 #include <netinet/in_systm.h>
  83 #ifdef INET
  84 #include <netinet/ip.h>
  85 #endif
  86 #ifdef INET6
  87 #include <netinet/ip6.h>
  88 #include <netinet6/ip6_var.h>
  89 #include <netinet6/ip6_private.h>
  90 #include <netinet6/in6_var.h>
  91 #include <netinet6/ip6_etherip.h>
  92 #endif
  93
  94 #include <net/if_ether.h>
  95 #include <net/if_media.h>
  96 #include <net/if_etherip.h>
  97 #if NBPFILTER > 0
  98 #include <net/bpf.h>
  99 #endif
 100
 101 #include <machine/stdarg.h>
 102
 103 int
 104 ip6_etherip_output(struct ifnet *ifp, struct mbuf *m)
 105 {
 106         struct rtentry *rt;
 107         struct etherip_softc *sc = (struct etherip_softc *)ifp->if_softc;
 108         struct sockaddr_in6 *sin6_src, *sin6_dst;
 109         struct ip6_hdr *ip6;    /* capsule IP header, host byte ordered */
 110         struct etherip_header eiphdr;
 111         int proto, error;
 112         union {
 113                 struct sockaddr         dst;
 114                 struct sockaddr_in6     dst6;
 115         } u;
 116
 117         sin6_src = (struct sockaddr_in6 *)sc->sc_src;
 118         sin6_dst = (struct sockaddr_in6 *)sc->sc_dst;
 119
 120         if (sin6_src == NULL ||
 121             sin6_dst == NULL ||
 122             sin6_src->sin6_family != AF_INET6 ||
 123             sin6_dst->sin6_family != AF_INET6) {
 124                 m_freem(m);
 125                 return EAFNOSUPPORT;
 126         }
 127
 128         /* reset broadcast/multicast flags */
 129         m->m_flags &= ~(M_BCAST|M_MCAST);
 130
 131         m->m_flags |= M_PKTHDR;
 132         proto = IPPROTO_ETHERIP;
 133
 134         /* fill and prepend Ethernet-in-IP header */
 135         eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
 136         eiphdr.eip_pad = 0;
 137         M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
 138         if (m == NULL)
 139                 return ENOBUFS;
 140         if (M_UNWRITABLE(m, sizeof(struct etherip_header))) {
 141                 m = m_pullup(m, sizeof(struct etherip_header));
 142                 if (m == NULL)
 143                         return ENOBUFS;
 144         }
 145         memcpy(mtod(m, struct etherip_header *), &eiphdr,
 146                sizeof(struct etherip_header));
 147
 148         /* prepend new IP header */
 149         M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
 150         if (m && m->m_len < sizeof(struct ip6_hdr))
 151                 m = m_pullup(m, sizeof(struct ip6_hdr));
 152         if (m == NULL)
 153                 return ENOBUFS;
 154
 155         ip6 = mtod(m, struct ip6_hdr *);
 156         ip6->ip6_flow = 0;
 157         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
 158         ip6->ip6_vfc |= IPV6_VERSION;
 159         ip6->ip6_nxt  = proto;
 160         ip6->ip6_hlim = ETHERIP_TTL;
 161         ip6->ip6_src  = sin6_src->sin6_addr;
 162
 163         /* bidirectional configured tunnel mode */
 164         if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
 165                 ip6->ip6_dst = sin6_dst->sin6_addr;
 166         else  {
 167                 m_freem(m);
 168                 return ENETUNREACH;
 169         }
 170
 171         sockaddr_in6_init(&u.dst6, &sin6_dst->sin6_addr, 0, 0, 0);
 172         if ((rt = rtcache_lookup(&sc->sc_ro, &u.dst)) == NULL) {
 173                 m_freem(m);
 174                 return ENETUNREACH;
 175         }
 176         /* if it constitutes infinite encapsulation, punt. */
 177         if (rt->rt_ifp == ifp) {
 178                 rtcache_free(&sc->sc_ro);
 179                 m_freem(m);
 180                 return ENETUNREACH;     /* XXX */
 181         }
 182
 183         /*
 184          * force fragmentation to minimum MTU, to avoid path MTU discovery.
 185          * it is too painful to ask for resend of inner packet, to achieve
 186          * path MTU discovery for encapsulated packets.
 187          */
 188         error = ip6_output(m, 0, &sc->sc_ro, IPV6_MINMTU, NULL, NULL, NULL);
 189
 190         return error;
 191 }
 192
 193 int
 194 ip6_etherip_input(struct mbuf *m, ...)
 195 {
 196         struct etherip_softc *sc;
 197         const struct ip6_hdr *ip6;
 198         struct sockaddr_in6 *src6, *dst6;
 199         struct ifnet *ifp = NULL;
 200         int off, proto, s;
 201         va_list ap;
 202
 203         va_start(ap, m);
 204         off = va_arg(ap, int);
 205         proto = va_arg(ap, int);
 206         va_end(ap);
 207
 208         if (proto != IPPROTO_ETHERIP) {
 209                 m_freem(m);
 210                 IP6_STATINC(IP6_STAT_NOGIF);
 211                 return IPPROTO_DONE;
 212         }
 213
 214         ip6 = mtod(m, const struct ip6_hdr *);
 215
 216         /* find device configured for this packets src and dst */
 217         LIST_FOREACH(sc, &etherip_softc_list, etherip_list) {
 218                 if( !sc->sc_src || !sc->sc_dst)
 219                         continue;
 220                 if (sc->sc_src->sa_family != AF_INET6 ||
 221                     sc->sc_dst->sa_family != AF_INET6)
 222                         continue;
 223
 224                 src6 = (struct sockaddr_in6 *)sc->sc_src;
 225                 dst6 = (struct sockaddr_in6 *)sc->sc_dst;
 226
 227                 if (!IN6_ARE_ADDR_EQUAL(&src6->sin6_addr, &ip6->ip6_dst) ||
 228                     !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_src))
 229                         continue;
 230
 231                 ifp = &sc->sc_ec.ec_if;
 232                 break;
 233         }
 234
 235         /* no matching device found */
 236         if (!ifp) {
 237                 m_freem(m);
 238                 IP6_STATINC(IP6_STAT_ODROPPED);
 239                 return IPPROTO_DONE;
 240         }
 241
 242         m_adj(m, off);
 243
 244         /*
 245          * Section 4 of RFC 3378 requires that the EtherIP header of incoming
 246          * packets is verified to contain the correct values in the version and
 247          * reserved fields, and packets with wrong values be dropped.
 248          *
 249          * There is some discussion about what exactly the header should look
 250          * like, the RFC is not very clear there. To be compatible with broken
 251          * implementations, we don't check the header on incoming packets,
 252          * relying on the ethernet code to filter out garbage.
 253          *
 254          * The header we use for sending is compatible with the original
 255          * implementation in OpenBSD, which was used in former NetBSD versions
 256          * and is used in FreeBSD. One Linux implementation is known to use the
 257          * same value.
 258          */
 259         m_adj(m, sizeof(struct etherip_header));
 260         m = m_pullup(m, sizeof(struct ether_header));
 261         if (m == NULL) {
 262                 ifp->if_ierrors++;
 263                 return IPPROTO_DONE;
 264         }
 265
 266         m->m_pkthdr.rcvif = ifp;
 267         m->m_flags &= ~(M_BCAST|M_MCAST);
 268
 269 #if NBPFILTER > 0
 270         if (ifp->if_bpf)
 271                 bpf_mtap(ifp->if_bpf, m);
 272 #endif
 273
 274         ifp->if_ipackets++;
 275
 276         s = splnet();
 277         (ifp->if_input)(ifp, m);
 278         splx(s);
 279
 280         return IPPROTO_DONE;
 281 }