in_gif.c

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    1 /*      $NetBSD: in_gif.c,v 1.51 2006/11/23 04:07:07 rpaulo 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 1.51 2006/11/23 04:07:07 rpaulo 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 #include <sys/kernel.h>
   49 
   50 #include <net/if.h>
   51 #include <net/route.h>
   52 
   53 #include <netinet/in.h>
   54 #include <netinet/in_systm.h>
   55 #include <netinet/ip.h>
   56 #include <netinet/ip_var.h>
   57 #include <netinet/in_gif.h>
   58 #include <netinet/in_var.h>
   59 #include <netinet/ip_encap.h>
   60 #include <netinet/ip_ecn.h>
   61 
   62 #ifdef INET6
   63 #include <netinet/ip6.h>
   64 #endif
   65 
   66 #include <net/if_gif.h>
   67 
   68 #include "gif.h"
   69 
   70 #include <machine/stdarg.h>
   71 
   72 #include <net/net_osdep.h>
   73 
   74 static int gif_validate4(const struct ip *, struct gif_softc *,
   75         struct ifnet *);
   76 
   77 #if NGIF > 0
   78 int ip_gif_ttl = GIF_TTL;
   79 #else
   80 int ip_gif_ttl = 0;
   81 #endif
   82 
   83 const struct protosw in_gif_protosw =
   84 { SOCK_RAW,     &inetdomain,    0/* IPPROTO_IPV[46] */, PR_ATOMIC|PR_ADDR,
   85   in_gif_input, rip_output,     0,              rip_ctloutput,
   86   rip_usrreq,
   87   0,            0,              0,              0,
   88 };
   89 
   90 int
   91 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
   92 {
   93         struct gif_softc *sc = (struct gif_softc*)ifp;
   94         struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
   95         struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
   96         struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
   97         struct ip iphdr;        /* capsule IP header, host byte ordered */
   98         int proto, error;
   99         u_int8_t tos;
  100 
  101         if (sin_src == NULL || sin_dst == NULL ||
  102             sin_src->sin_family != AF_INET ||
  103             sin_dst->sin_family != AF_INET) {
  104                 m_freem(m);
  105                 return EAFNOSUPPORT;
  106         }
  107 
  108         switch (family) {
  109 #ifdef INET
  110         case AF_INET:
  111             {
  112                 const struct ip *ip;
  113 
  114                 proto = IPPROTO_IPV4;
  115                 if (m->m_len < sizeof(*ip)) {
  116                         m = m_pullup(m, sizeof(*ip));
  117                         if (m == NULL)
  118                                 return ENOBUFS;
  119                 }
  120                 ip = mtod(m, const struct ip *);
  121                 tos = ip->ip_tos;
  122                 break;
  123             }
  124 #endif /* INET */
  125 #ifdef INET6
  126         case AF_INET6:
  127             {
  128                 const struct ip6_hdr *ip6;
  129                 proto = IPPROTO_IPV6;
  130                 if (m->m_len < sizeof(*ip6)) {
  131                         m = m_pullup(m, sizeof(*ip6));
  132                         if (!m)
  133                                 return ENOBUFS;
  134                 }
  135                 ip6 = mtod(m, const struct ip6_hdr *);
  136                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  137                 break;
  138             }
  139 #endif /* INET6 */
  140 #ifdef ISO
  141         case AF_ISO:
  142                 proto = IPPROTO_EON;
  143                 tos = 0;
  144                 break;
  145 #endif
  146         default:
  147 #ifdef DEBUG
  148                 printf("in_gif_output: warning: unknown family %d passed\n",
  149                         family);
  150 #endif
  151                 m_freem(m);
  152                 return EAFNOSUPPORT;
  153         }
  154 
  155         bzero(&iphdr, sizeof(iphdr));
  156         iphdr.ip_src = sin_src->sin_addr;
  157         /* bidirectional configured tunnel mode */
  158         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
  159                 iphdr.ip_dst = sin_dst->sin_addr;
  160         else {
  161                 m_freem(m);
  162                 return ENETUNREACH;
  163         }
  164         iphdr.ip_p = proto;
  165         /* version will be set in ip_output() */
  166         iphdr.ip_ttl = ip_gif_ttl;
  167         iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
  168         if (ifp->if_flags & IFF_LINK1)
  169                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
  170         else
  171                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
  172 
  173         /* prepend new IP header */
  174         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
  175         /* XXX Is m_pullup really necessary after M_PREPEND? */
  176         if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip)))
  177                 m = m_pullup(m, sizeof(struct ip));
  178         if (m == NULL)
  179                 return ENOBUFS;
  180         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
  181 
  182         if (sc->gif_route_expire - time_second <= 0 ||
  183             dst->sin_family != sin_dst->sin_family ||
  184             !in_hosteq(dst->sin_addr, sin_dst->sin_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                 sc->gif_route_expire = time_second + GIF_ROUTE_TTL;
  210         }
  211 
  212         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
  213         return (error);
  214 }
  215 
  216 void
  217 in_gif_input(struct mbuf *m, ...)
  218 {
  219         int off, proto;
  220         struct ifnet *gifp = NULL;
  221         const struct ip *ip;
  222         va_list ap;
  223         int af;
  224         u_int8_t otos;
  225 
  226         va_start(ap, m);
  227         off = va_arg(ap, int);
  228         proto = va_arg(ap, int);
  229         va_end(ap);
  230 
  231         ip = mtod(m, const struct ip *);
  232 
  233         gifp = (struct ifnet *)encap_getarg(m);
  234 
  235         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
  236                 m_freem(m);
  237                 ipstat.ips_nogif++;
  238                 return;
  239         }
  240 #ifndef GIF_ENCAPCHECK
  241         if (!gif_validate4(ip, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
  242                 m_freem(m);
  243                 ipstat.ips_nogif++;
  244                 return;
  245         }
  246 #endif
  247 
  248         otos = ip->ip_tos;
  249         m_adj(m, off);
  250 
  251         switch (proto) {
  252 #ifdef INET
  253         case IPPROTO_IPV4:
  254             {
  255                 struct ip *xip;
  256                 af = AF_INET;
  257                 if (M_UNWRITABLE(m, sizeof(*xip))) {
  258                         if ((m = m_pullup(m, sizeof(*xip))) == NULL)
  259                                 return;
  260                 }
  261                 xip = mtod(m, struct ip *);
  262                 if (gifp->if_flags & IFF_LINK1)
  263                         ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos);
  264                 else
  265                         ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos);
  266                 break;
  267             }
  268 #endif
  269 #ifdef INET6
  270         case IPPROTO_IPV6:
  271             {
  272                 struct ip6_hdr *ip6;
  273                 u_int8_t itos;
  274                 af = AF_INET6;
  275                 if (M_UNWRITABLE(m, sizeof(*ip6))) {
  276                         if ((m = m_pullup(m, sizeof(*ip6))) == NULL)
  277                                 return;
  278                 }
  279                 ip6 = mtod(m, struct ip6_hdr *);
  280                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  281                 if (gifp->if_flags & IFF_LINK1)
  282                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
  283                 else
  284                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
  285                 ip6->ip6_flow &= ~htonl(0xff << 20);
  286                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
  287                 break;
  288             }
  289 #endif /* INET6 */
  290 #ifdef ISO
  291         case IPPROTO_EON:
  292                 af = AF_ISO;
  293                 break;
  294 #endif
  295         default:
  296                 ipstat.ips_nogif++;
  297                 m_freem(m);
  298                 return;
  299         }
  300         gif_input(m, af, gifp);
  301         return;
  302 }
  303 
  304 /*
  305  * validate outer address.
  306  */
  307 static int
  308 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
  309 {
  310         struct sockaddr_in *src, *dst;
  311         struct in_ifaddr *ia4;
  312 
  313         src = (struct sockaddr_in *)sc->gif_psrc;
  314         dst = (struct sockaddr_in *)sc->gif_pdst;
  315 
  316         /* check for address match */
  317         if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
  318             dst->sin_addr.s_addr != ip->ip_src.s_addr)
  319                 return 0;
  320 
  321         /* martian filters on outer source - NOT done in ip_input! */
  322         if (IN_MULTICAST(ip->ip_src.s_addr))
  323                 return 0;
  324         switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
  325         case 0: case 127: case 255:
  326                 return 0;
  327         }
  328         /* reject packets with broadcast on source */
  329         TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
  330                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
  331                         continue;
  332                 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
  333                         return 0;
  334         }
  335 
  336         /* ingress filters on outer source */
  337         if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
  338                 struct sockaddr_in sin;
  339                 struct rtentry *rt;
  340 
  341                 bzero(&sin, sizeof(sin));
  342                 sin.sin_family = AF_INET;
  343                 sin.sin_len = sizeof(struct sockaddr_in);
  344                 sin.sin_addr = ip->ip_src;
  345                 rt = rtalloc1((struct sockaddr *)&sin, 0);
  346                 if (!rt || rt->rt_ifp != ifp) {
  347 #if 0
  348                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
  349                             "due to ingress filter\n", if_name(&sc->gif_if),
  350                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
  351 #endif
  352                         if (rt)
  353                                 rtfree(rt);
  354                         return 0;
  355                 }
  356                 rtfree(rt);
  357         }
  358 
  359         return 32 * 2;
  360 }
  361 
  362 #ifdef GIF_ENCAPCHECK
  363 /*
  364  * we know that we are in IFF_UP, outer address available, and outer family
  365  * matched the physical addr family.  see gif_encapcheck().
  366  */
  367 int
  368 gif_encapcheck4(struct mbuf *m, int off, int proto, void *arg)
  369 {
  370         struct ip ip;
  371         struct gif_softc *sc;
  372         struct ifnet *ifp;
  373 
  374         /* sanity check done in caller */
  375         sc = (struct gif_softc *)arg;
  376 
  377         m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
  378         ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
  379 
  380         return gif_validate4(&ip, sc, ifp);
  381 }
  382 #endif
  383 
  384 int
  385 in_gif_attach(struct gif_softc *sc)
  386 {
  387 #ifndef GIF_ENCAPCHECK
  388         struct sockaddr_in mask4;
  389 
  390         bzero(&mask4, sizeof(mask4));
  391         mask4.sin_len = sizeof(struct sockaddr_in);
  392         mask4.sin_addr.s_addr = ~0;
  393 
  394         if (!sc->gif_psrc || !sc->gif_pdst)
  395                 return EINVAL;
  396         sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
  397             (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
  398             (const struct protosw *)&in_gif_protosw, sc);
  399 #else
  400         sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
  401             &in_gif_protosw, sc);
  402 #endif
  403         if (sc->encap_cookie4 == NULL)
  404                 return EEXIST;
  405         return 0;
  406 }
  407 
  408 int
  409 in_gif_detach(struct gif_softc *sc)
  410 {
  411         int error;
  412 
  413         error = encap_detach(sc->encap_cookie4);
  414         if (error == 0)
  415                 sc->encap_cookie4 = NULL;
  416 
  417         if (sc->gif_ro.ro_rt) {
  418                 RTFREE(sc->gif_ro.ro_rt);
  419                 sc->gif_ro.ro_rt = NULL;
  420         }
  421 
  422         return error;
  423 }
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FreeBSD/Linux Kernel Cross Reference sys/netinet/in_gif.c

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