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 error, len, proto;
  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         len = sizeof(struct ip);
  186 #ifndef __NO_STRICT_ALIGNMENT
  187         if (family == AF_LINK)
  188                 len += ETHERIP_ALIGN;
  189 #endif
  190         M_PREPEND(m, len, M_DONTWAIT);
  191         if (m != NULL && m->m_len < len)
  192                 m = m_pullup(m, len);
  193         if (m == NULL) {
  194                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
  195                 return ENOBUFS;
  196         }
  197 #ifndef __NO_STRICT_ALIGNMENT
  198         if (family == AF_LINK) {
  199                 len = mtod(m, vm_offset_t) & 3;
  200                 KASSERT(len == 0 || len == ETHERIP_ALIGN,
  201                     ("in_gif_output: unexpected misalignment"));
  202                 m->m_data += len;
  203                 m->m_len -= ETHERIP_ALIGN;
  204         }
  205 #endif
  206         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
  207 
  208         M_SETFIB(m, sc->gif_fibnum);
  209 
  210         if (dst->sin_family != sin_dst->sin_family ||
  211             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
  212                 /* cache route doesn't match */
  213                 bzero(dst, sizeof(*dst));
  214                 dst->sin_family = sin_dst->sin_family;
  215                 dst->sin_len = sizeof(struct sockaddr_in);
  216                 dst->sin_addr = sin_dst->sin_addr;
  217                 if (sc->gif_ro.ro_rt) {
  218                         RTFREE(sc->gif_ro.ro_rt);
  219                         sc->gif_ro.ro_rt = NULL;
  220                 }
  221 #if 0
  222                 GIF2IFP(sc)->if_mtu = GIF_MTU;
  223 #endif
  224         }
  225 
  226         if (sc->gif_ro.ro_rt == NULL) {
  227                 in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
  228                 if (sc->gif_ro.ro_rt == NULL) {
  229                         m_freem(m);
  230                         return ENETUNREACH;
  231                 }
  232 
  233                 /* if it constitutes infinite encapsulation, punt. */
  234                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
  235                         m_freem(m);
  236                         return ENETUNREACH;     /* XXX */
  237                 }
  238 #if 0
  239                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
  240                         - sizeof(struct ip);
  241 #endif
  242         }
  243 
  244         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
  245 
  246         if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
  247             sc->gif_ro.ro_rt != NULL) {
  248                 RTFREE(sc->gif_ro.ro_rt);
  249                 sc->gif_ro.ro_rt = NULL;
  250         }
  251 
  252         return (error);
  253 }
  254 
  255 void
  256 in_gif_input(struct mbuf *m, int off)
  257 {
  258         struct ifnet *gifp = NULL;
  259         struct gif_softc *sc;
  260         struct ip *ip;
  261         int af;
  262         u_int8_t otos;
  263         int proto;
  264 
  265         ip = mtod(m, struct ip *);
  266         proto = ip->ip_p;
  267 
  268         sc = (struct gif_softc *)encap_getarg(m);
  269         if (sc == NULL) {
  270                 m_freem(m);
  271                 ipstat.ips_nogif++;
  272                 return;
  273         }
  274 
  275         gifp = GIF2IFP(sc);
  276         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
  277                 m_freem(m);
  278                 ipstat.ips_nogif++;
  279                 return;
  280         }
  281 
  282         otos = ip->ip_tos;
  283         m_adj(m, off);
  284 
  285         switch (proto) {
  286 #ifdef INET
  287         case IPPROTO_IPV4:
  288             {
  289                 struct ip *ip;
  290                 af = AF_INET;
  291                 if (m->m_len < sizeof(*ip)) {
  292                         m = m_pullup(m, sizeof(*ip));
  293                         if (!m)
  294                                 return;
  295                 }
  296                 ip = mtod(m, struct ip *);
  297                 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
  298                                   ECN_ALLOWED : ECN_NOCARE,
  299                                   &otos, &ip->ip_tos) == 0) {
  300                         m_freem(m);
  301                         return;
  302                 }
  303                 break;
  304             }
  305 #endif
  306 #ifdef INET6
  307         case IPPROTO_IPV6:
  308             {
  309                 struct ip6_hdr *ip6;
  310                 u_int8_t itos, oitos;
  311 
  312                 af = AF_INET6;
  313                 if (m->m_len < sizeof(*ip6)) {
  314                         m = m_pullup(m, sizeof(*ip6));
  315                         if (!m)
  316                                 return;
  317                 }
  318                 ip6 = mtod(m, struct ip6_hdr *);
  319                 itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  320                 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
  321                                   ECN_ALLOWED : ECN_NOCARE,
  322                                   &otos, &itos) == 0) {
  323                         m_freem(m);
  324                         return;
  325                 }
  326                 if (itos != oitos) {
  327                         ip6->ip6_flow &= ~htonl(0xff << 20);
  328                         ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
  329                 }
  330                 break;
  331             }
  332 #endif /* INET6 */
  333         case IPPROTO_ETHERIP:
  334                 af = AF_LINK;
  335                 break;  
  336 
  337         default:
  338                 ipstat.ips_nogif++;
  339                 m_freem(m);
  340                 return;
  341         }
  342         gif_input(m, af, gifp);
  343         return;
  344 }
  345 
  346 /*
  347  * validate outer address.
  348  */
  349 static int
  350 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
  351 {
  352         struct sockaddr_in *src, *dst;
  353         struct in_ifaddr *ia4;
  354 
  355         src = (struct sockaddr_in *)sc->gif_psrc;
  356         dst = (struct sockaddr_in *)sc->gif_pdst;
  357 
  358         /* check for address match */
  359         if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
  360             dst->sin_addr.s_addr != ip->ip_src.s_addr)
  361                 return 0;
  362 
  363         /* martian filters on outer source - NOT done in ip_input! */
  364         if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
  365                 return 0;
  366         switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
  367         case 0: case 127: case 255:
  368                 return 0;
  369         }
  370         /* reject packets with broadcast on source */
  371         TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
  372                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
  373                         continue;
  374                 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
  375                         return 0;
  376         }
  377 
  378         /* ingress filters on outer source */
  379         if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
  380                 struct sockaddr_in sin;
  381                 struct rtentry *rt;
  382 
  383                 bzero(&sin, sizeof(sin));
  384                 sin.sin_family = AF_INET;
  385                 sin.sin_len = sizeof(struct sockaddr_in);
  386                 sin.sin_addr = ip->ip_src;
  387                 /* XXX MRT  check for the interface we would use on output */
  388                 rt = in_rtalloc1((struct sockaddr *)&sin, 0,
  389                     0UL, sc->gif_fibnum);
  390                 if (!rt || rt->rt_ifp != ifp) {
  391 #if 0
  392                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
  393                             "due to ingress filter\n", if_name(GIF2IFP(sc)),
  394                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
  395 #endif
  396                         if (rt)
  397                                 RTFREE_LOCKED(rt);
  398                         return 0;
  399                 }
  400                 RTFREE_LOCKED(rt);
  401         }
  402 
  403         return 32 * 2;
  404 }
  405 
  406 /*
  407  * we know that we are in IFF_UP, outer address available, and outer family
  408  * matched the physical addr family.  see gif_encapcheck().
  409  */
  410 int
  411 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
  412 {
  413         struct ip ip;
  414         struct gif_softc *sc;
  415         struct ifnet *ifp;
  416 
  417         /* sanity check done in caller */
  418         sc = (struct gif_softc *)arg;
  419 
  420         /* LINTED const cast */
  421         m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
  422         ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
  423 
  424         return gif_validate4(&ip, sc, ifp);
  425 }
  426 
  427 int
  428 in_gif_attach(struct gif_softc *sc)
  429 {
  430         sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
  431             &in_gif_protosw, sc);
  432         if (sc->encap_cookie4 == NULL)
  433                 return EEXIST;
  434         return 0;
  435 }
  436 
  437 int
  438 in_gif_detach(struct gif_softc *sc)
  439 {
  440         int error;
  441 
  442         error = encap_detach(sc->encap_cookie4);
  443         if (error == 0)
  444                 sc->encap_cookie4 = NULL;
  445         return error;
  446 }
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FreeBSD/Linux Kernel Cross Reference sys/netinet/in_gif.c

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