in_gif.c

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    1 /*      $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ */
    2 
    3 /*-
    4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    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 the project nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD$");
   34 
   35 #include "opt_mrouting.h"
   36 #include "opt_inet.h"
   37 #include "opt_inet6.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/kernel.h>
   46 #include <sys/sysctl.h>
   47 #include <sys/protosw.h>
   48 
   49 #include <sys/malloc.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 #ifdef MROUTING
   68 #include <netinet/ip_mroute.h>
   69 #endif /* MROUTING */
   70 
   71 #include <net/if_gif.h> 
   72 
   73 static int gif_validate4(const struct ip *, struct gif_softc *,
   74         struct ifnet *);
   75 
   76 extern  struct domain inetdomain;
   77 struct protosw in_gif_protosw = {
   78         .pr_type =              SOCK_RAW,
   79         .pr_domain =            &inetdomain,
   80         .pr_protocol =          0/* IPPROTO_IPV[46] */,
   81         .pr_flags =             PR_ATOMIC|PR_ADDR,
   82         .pr_input =             in_gif_input,
   83         .pr_output =            (pr_output_t*)rip_output,
   84         .pr_ctloutput =         rip_ctloutput,
   85         .pr_usrreqs =           &rip_usrreqs
   86 };
   87 
   88 static int ip_gif_ttl = GIF_TTL;
   89 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
   90         &ip_gif_ttl,    0, "");
   91 
   92 int
   93 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
   94 {
   95         struct gif_softc *sc = ifp->if_softc;
   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         struct etherip_header eiphdr;
  101         int proto, error;
  102         u_int8_t tos;
  103 
  104         GIF_LOCK_ASSERT(sc);
  105 
  106         if (sin_src == NULL || sin_dst == NULL ||
  107             sin_src->sin_family != AF_INET ||
  108             sin_dst->sin_family != AF_INET) {
  109                 m_freem(m);
  110                 return EAFNOSUPPORT;
  111         }
  112 
  113         switch (family) {
  114 #ifdef INET
  115         case AF_INET:
  116             {
  117                 struct ip *ip;
  118 
  119                 proto = IPPROTO_IPV4;
  120                 if (m->m_len < sizeof(*ip)) {
  121                         m = m_pullup(m, sizeof(*ip));
  122                         if (!m)
  123                                 return ENOBUFS;
  124                 }
  125                 ip = mtod(m, struct ip *);
  126                 tos = ip->ip_tos;
  127                 break;
  128             }
  129 #endif /* INET */
  130 #ifdef INET6
  131         case AF_INET6:
  132             {
  133                 struct ip6_hdr *ip6;
  134                 proto = IPPROTO_IPV6;
  135                 if (m->m_len < sizeof(*ip6)) {
  136                         m = m_pullup(m, sizeof(*ip6));
  137                         if (!m)
  138                                 return ENOBUFS;
  139                 }
  140                 ip6 = mtod(m, struct ip6_hdr *);
  141                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  142                 break;
  143             }
  144 #endif /* INET6 */
  145         case AF_LINK:
  146                 proto = IPPROTO_ETHERIP;
  147                 eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
  148                 eiphdr.eip_pad = 0;
  149                 /* prepend Ethernet-in-IP header */
  150                 M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
  151                 if (m && m->m_len < sizeof(struct etherip_header))
  152                         m = m_pullup(m, sizeof(struct etherip_header));
  153                 if (m == NULL)
  154                         return ENOBUFS;
  155                 bcopy(&eiphdr, mtod(m, struct etherip_header *),
  156                     sizeof(struct etherip_header));
  157                 break;
  158 
  159         default:
  160 #ifdef DEBUG
  161                 printf("in_gif_output: warning: unknown family %d passed\n",
  162                         family);
  163 #endif
  164                 m_freem(m);
  165                 return EAFNOSUPPORT;
  166         }
  167 
  168         bzero(&iphdr, sizeof(iphdr));
  169         iphdr.ip_src = sin_src->sin_addr;
  170         /* bidirectional configured tunnel mode */
  171         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
  172                 iphdr.ip_dst = sin_dst->sin_addr;
  173         else {
  174                 m_freem(m);
  175                 return ENETUNREACH;
  176         }
  177         iphdr.ip_p = proto;
  178         /* version will be set in ip_output() */
  179         iphdr.ip_ttl = ip_gif_ttl;
  180         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
  181         ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
  182                        &iphdr.ip_tos, &tos);
  183 
  184         /* prepend new IP header */
  185         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
  186         if (m && m->m_len < sizeof(struct ip))
  187                 m = m_pullup(m, sizeof(struct ip));
  188         if (m == NULL) {
  189                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
  190                 return ENOBUFS;
  191         }
  192         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
  193 
  194         if (dst->sin_family != sin_dst->sin_family ||
  195             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
  196                 /* cache route doesn't match */
  197                 bzero(dst, sizeof(*dst));
  198                 dst->sin_family = sin_dst->sin_family;
  199                 dst->sin_len = sizeof(struct sockaddr_in);
  200                 dst->sin_addr = sin_dst->sin_addr;
  201                 if (sc->gif_ro.ro_rt) {
  202                         RTFREE(sc->gif_ro.ro_rt);
  203                         sc->gif_ro.ro_rt = NULL;
  204                 }
  205 #if 0
  206                 GIF2IFP(sc)->if_mtu = GIF_MTU;
  207 #endif
  208         }
  209 
  210         if (sc->gif_ro.ro_rt == NULL) {
  211                 rtalloc_ign(&sc->gif_ro, 0);
  212                 if (sc->gif_ro.ro_rt == NULL) {
  213                         m_freem(m);
  214                         return ENETUNREACH;
  215                 }
  216 
  217                 /* if it constitutes infinite encapsulation, punt. */
  218                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
  219                         m_freem(m);
  220                         return ENETUNREACH;     /* XXX */
  221                 }
  222 #if 0
  223                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
  224                         - sizeof(struct ip);
  225 #endif
  226         }
  227 
  228         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
  229 
  230         if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
  231             sc->gif_ro.ro_rt != NULL) {
  232                 RTFREE(sc->gif_ro.ro_rt);
  233                 sc->gif_ro.ro_rt = NULL;
  234         }
  235 
  236         return (error);
  237 }
  238 
  239 void
  240 in_gif_input(struct mbuf *m, int off)
  241 {
  242         struct ifnet *gifp = NULL;
  243         struct gif_softc *sc;
  244         struct ip *ip;
  245         int af;
  246         u_int8_t otos;
  247         int proto;
  248 
  249         ip = mtod(m, struct ip *);
  250         proto = ip->ip_p;
  251 
  252         sc = (struct gif_softc *)encap_getarg(m);
  253         if (sc == NULL) {
  254                 m_freem(m);
  255                 ipstat.ips_nogif++;
  256                 return;
  257         }
  258 
  259         gifp = GIF2IFP(sc);
  260         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
  261                 m_freem(m);
  262                 ipstat.ips_nogif++;
  263                 return;
  264         }
  265 
  266         otos = ip->ip_tos;
  267         m_adj(m, off);
  268 
  269         switch (proto) {
  270 #ifdef INET
  271         case IPPROTO_IPV4:
  272             {
  273                 struct ip *ip;
  274                 af = AF_INET;
  275                 if (m->m_len < sizeof(*ip)) {
  276                         m = m_pullup(m, sizeof(*ip));
  277                         if (!m)
  278                                 return;
  279                 }
  280                 ip = mtod(m, struct ip *);
  281                 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
  282                                   ECN_ALLOWED : ECN_NOCARE,
  283                                   &otos, &ip->ip_tos) == 0) {
  284                         m_freem(m);
  285                         return;
  286                 }
  287                 break;
  288             }
  289 #endif
  290 #ifdef INET6
  291         case IPPROTO_IPV6:
  292             {
  293                 struct ip6_hdr *ip6;
  294                 u_int8_t itos, oitos;
  295 
  296                 af = AF_INET6;
  297                 if (m->m_len < sizeof(*ip6)) {
  298                         m = m_pullup(m, sizeof(*ip6));
  299                         if (!m)
  300                                 return;
  301                 }
  302                 ip6 = mtod(m, struct ip6_hdr *);
  303                 itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  304                 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
  305                                   ECN_ALLOWED : ECN_NOCARE,
  306                                   &otos, &itos) == 0) {
  307                         m_freem(m);
  308                         return;
  309                 }
  310                 if (itos != oitos) {
  311                         ip6->ip6_flow &= ~htonl(0xff << 20);
  312                         ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
  313                 }
  314                 break;
  315             }
  316 #endif /* INET6 */
  317         case IPPROTO_ETHERIP:
  318                 af = AF_LINK;
  319                 break;  
  320 
  321         default:
  322                 ipstat.ips_nogif++;
  323                 m_freem(m);
  324                 return;
  325         }
  326         gif_input(m, af, gifp);
  327         return;
  328 }
  329 
  330 /*
  331  * validate outer address.
  332  */
  333 static int
  334 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
  335 {
  336         struct sockaddr_in *src, *dst;
  337         struct in_ifaddr *ia4;
  338 
  339         src = (struct sockaddr_in *)sc->gif_psrc;
  340         dst = (struct sockaddr_in *)sc->gif_pdst;
  341 
  342         /* check for address match */
  343         if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
  344             dst->sin_addr.s_addr != ip->ip_src.s_addr)
  345                 return 0;
  346 
  347         /* martian filters on outer source - NOT done in ip_input! */
  348         if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
  349                 return 0;
  350         switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
  351         case 0: case 127: case 255:
  352                 return 0;
  353         }
  354         /* reject packets with broadcast on source */
  355         TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
  356                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
  357                         continue;
  358                 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
  359                         return 0;
  360         }
  361 
  362         /* ingress filters on outer source */
  363         if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
  364                 struct sockaddr_in sin;
  365                 struct rtentry *rt;
  366 
  367                 bzero(&sin, sizeof(sin));
  368                 sin.sin_family = AF_INET;
  369                 sin.sin_len = sizeof(struct sockaddr_in);
  370                 sin.sin_addr = ip->ip_src;
  371                 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
  372                 if (!rt || rt->rt_ifp != ifp) {
  373 #if 0
  374                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
  375                             "due to ingress filter\n", if_name(GIF2IFP(sc)),
  376                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
  377 #endif
  378                         if (rt)
  379                                 RTFREE_LOCKED(rt);
  380                         return 0;
  381                 }
  382                 RTFREE_LOCKED(rt);
  383         }
  384 
  385         return 32 * 2;
  386 }
  387 
  388 /*
  389  * we know that we are in IFF_UP, outer address available, and outer family
  390  * matched the physical addr family.  see gif_encapcheck().
  391  */
  392 int
  393 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
  394 {
  395         struct ip ip;
  396         struct gif_softc *sc;
  397         struct ifnet *ifp;
  398 
  399         /* sanity check done in caller */
  400         sc = (struct gif_softc *)arg;
  401 
  402         /* LINTED const cast */
  403         m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
  404         ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
  405 
  406         return gif_validate4(&ip, sc, ifp);
  407 }
  408 
  409 int
  410 in_gif_attach(struct gif_softc *sc)
  411 {
  412         sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
  413             &in_gif_protosw, sc);
  414         if (sc->encap_cookie4 == NULL)
  415                 return EEXIST;
  416         return 0;
  417 }
  418 
  419 int
  420 in_gif_detach(struct gif_softc *sc)
  421 {
  422         int error;
  423 
  424         error = encap_detach(sc->encap_cookie4);
  425         if (error == 0)
  426                 sc->encap_cookie4 = NULL;
  427         return error;
  428 }
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FreeBSD/Linux Kernel Cross Reference sys/netinet/in_gif.c

FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_gif.c
