sys/netinet/ip_etherip.c

   1 /*      $NetBSD: ip_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: ip_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 #include <netinet/ip.h>
  84 #include <netinet/ip_var.h>
  85 #include <netinet/in_var.h>
  86 #include <netinet/ip_etherip.h>
  87
  88 #include <net/if_ether.h>
  89 #include <net/if_media.h>
  90 #include <net/if_etherip.h>
  91 #if NBPFILTER > 0
  92 #include <net/bpf.h>
  93 #endif
  94
  95 #include <machine/stdarg.h>
  96
  97 int
  98 ip_etherip_output(struct ifnet *ifp, struct mbuf *m)
  99 {
 100         struct rtentry *rt;
 101         struct etherip_softc *sc = (struct etherip_softc*)ifp->if_softc;
 102         struct sockaddr_in *sin_src, *sin_dst;
 103         struct ip iphdr;        /* capsule IP header, host byte ordered */
 104         struct etherip_header eiphdr;
 105         int proto, error;
 106         union {
 107                 struct sockaddr         dst;
 108                 struct sockaddr_in      dst4;
 109         } u;
 110
 111         sin_src = (struct sockaddr_in *)sc->sc_src;
 112         sin_dst = (struct sockaddr_in *)sc->sc_dst;
 113
 114         if (sin_src == NULL ||
 115             sin_dst == NULL ||
 116             sin_src->sin_family != AF_INET ||
 117             sin_dst->sin_family != AF_INET) {
 118                 m_freem(m);
 119                 return EAFNOSUPPORT;
 120         }
 121
 122         /* reset broadcast/multicast flags */
 123         m->m_flags &= ~(M_BCAST|M_MCAST);
 124
 125         m->m_flags |= M_PKTHDR;
 126         proto = IPPROTO_ETHERIP;
 127
 128         /* fill and prepend Ethernet-in-IP header */
 129         eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
 130         eiphdr.eip_pad = 0;
 131         M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
 132         if (m == NULL)
 133                 return ENOBUFS;
 134         if (M_UNWRITABLE(m, sizeof(struct etherip_header))) {
 135                 m = m_pullup(m, sizeof(struct etherip_header));
 136                 if (m == NULL)
 137                         return ENOBUFS;
 138         }
 139         memcpy(mtod(m, struct etherip_header *), &eiphdr,
 140                sizeof(struct etherip_header));
 141
 142         /* fill new IP header */
 143         memset(&iphdr, 0, sizeof(struct ip));
 144         iphdr.ip_src = sin_src->sin_addr;
 145         /* bidirectional configured tunnel mode */
 146         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 147                 iphdr.ip_dst = sin_dst->sin_addr;
 148         else {
 149                 m_freem(m);
 150                 return ENETUNREACH;
 151         }
 152         iphdr.ip_p = proto;
 153         /* version will be set in ip_output() */
 154         iphdr.ip_ttl = ETHERIP_TTL;
 155         iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
 156
 157         /* prepend new IP header */
 158         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 159         if (m == NULL)
 160                 return ENOBUFS;
 161         if (M_UNWRITABLE(m, sizeof(struct ip)))
 162                 m = m_pullup(m, sizeof(struct ip));
 163         memcpy(mtod(m, struct ip *), &iphdr, sizeof(struct ip));
 164
 165         sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0);
 166         if ((rt = rtcache_lookup(&sc->sc_ro, &u.dst)) == NULL) {
 167                 m_freem(m);
 168                 return ENETUNREACH;
 169         }
 170
 171         /* if it constitutes infinite encapsulation, punt. */
 172         if (rt->rt_ifp == ifp) {
 173                 rtcache_free(&sc->sc_ro);
 174                 m_freem(m);
 175                 return ENETUNREACH;     /*XXX*/
 176         }
 177
 178         error = ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL);
 179
 180         return error;
 181 }
 182
 183 void
 184 ip_etherip_input(struct mbuf *m, ...)
 185 {
 186         struct etherip_softc *sc;
 187         const struct ip *ip;
 188         struct sockaddr_in *src, *dst;
 189         struct ifnet *ifp = NULL;
 190         int off, proto, s;
 191         va_list ap;
 192
 193         va_start(ap, m);
 194         off = va_arg(ap, int);
 195         proto = va_arg(ap, int);
 196         va_end(ap);
 197
 198         if (proto != IPPROTO_ETHERIP) {
 199                 m_freem(m);
 200                 ip_statinc(IP_STAT_NOPROTO);
 201                 return;
 202         }
 203
 204         ip = mtod(m, const struct ip *);
 205
 206         /* find device configured for this packets src and dst */
 207         LIST_FOREACH(sc, &etherip_softc_list, etherip_list) {
 208                 if (!sc->sc_src || !sc->sc_dst)
 209                         continue;
 210
 211                 if (sc->sc_src->sa_family != AF_INET ||
 212                     sc->sc_dst->sa_family != AF_INET)
 213                         continue;
 214
 215                 src = (struct sockaddr_in *)sc->sc_src;
 216                 dst = (struct sockaddr_in *)sc->sc_dst;
 217
 218                 if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
 219                     dst->sin_addr.s_addr != ip->ip_src.s_addr)
 220                         continue;
 221
 222                 ifp = &sc->sc_ec.ec_if;
 223                 break;
 224         }
 225
 226         /* no matching device found */
 227         if (!ifp) {
 228                 m_freem(m);
 229                 ip_statinc(IP_STAT_ODROPPED);
 230                 return;
 231         }
 232
 233         m_adj(m, off);
 234
 235         /*
 236          * Section 4 of RFC 3378 requires that the EtherIP header of incoming
 237          * packets is verified to contain the correct values in the version and
 238          * reserved fields, and packets with wrong values be dropped.
 239          *
 240          * There is some discussion about what exactly the header should look
 241          * like, the RFC is not very clear there. To be compatible with broken
 242          * implementations, we don't check the header on incoming packets,
 243          * relying on the ethernet code to filter out garbage.
 244          *
 245          * The header we use for sending is compatible with the original
 246          * implementation in OpenBSD, which was used in former NetBSD versions
 247          * and is used in FreeBSD. One Linux implementation is known to use the
 248          * same value.
 249          */
 250         m_adj(m, sizeof(struct etherip_header));
 251         m = m_pullup(m, sizeof(struct ether_header));
 252         if (m == NULL) {
 253                 ifp->if_ierrors++;
 254                 return;
 255         }
 256
 257         m->m_pkthdr.rcvif = ifp;
 258         m->m_flags &= ~(M_BCAST|M_MCAST);
 259
 260 #if NBPFILTER > 0
 261         if (ifp->if_bpf)
 262                 bpf_mtap(ifp->if_bpf, m);
 263 #endif
 264
 265         ifp->if_ipackets++;
 266
 267         s = splnet();
 268         (ifp->if_input)(ifp, m);
 269         splx(s);
 270
 271         return;
 272 }
 273