sys/netinet/in_gif.c

   1 /*
   2  * $FreeBSD: src/sys/netinet/in_gif.c,v 1.5.2.11 2003/01/23 21:06:45 sam Exp $
   3  * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $
   4  */
   5 /*
   6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the project nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "opt_inet.h"
  35 #include "opt_inet6.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/socket.h>
  40 #include <sys/sockio.h>
  41 #include <sys/mbuf.h>
  42 #include <sys/errno.h>
  43 #include <sys/kernel.h>
  44 #include <sys/sysctl.h>
  45 #include <sys/protosw.h>
  46
  47 #include <sys/malloc.h>
  48
  49 #include <machine/stdarg.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 #include <net/gif/if_gif.h>
  68 #include <net/net_osdep.h>
  69
  70 #ifdef INET
  71 static int gif_validate4 (const struct ip *, struct gif_softc *,
  72                           struct ifnet *);
  73
  74 extern  struct domain inetdomain;
  75 const struct protosw in_gif_protosw =
  76     {
  77         .pr_type = SOCK_RAW,
  78         .pr_domain = &inetdomain,
  79         .pr_protocol = 0 /*IPPROTO_IPV[46]*/,
  80         .pr_flags = PR_ATOMIC|PR_ADDR,
  81
  82         .pr_input = in_gif_input,
  83         .pr_output = rip_output,
  84         .pr_ctlinput = NULL,
  85         .pr_ctloutput = rip_ctloutput,
  86
  87         .pr_ctlport = NULL,
  88         .pr_usrreqs = &rip_usrreqs
  89     };
  90
  91 int ip_gif_ttl = GIF_TTL;
  92 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
  93         &ip_gif_ttl, 0, "TTL of GIF packet");
  94
  95 int
  96 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
  97 {
  98         struct gif_softc *sc = (struct gif_softc*)ifp;
  99         struct route *ro = &sc->gif_ro[mycpu->gd_cpuid];
 100         struct sockaddr_in *dst = (struct sockaddr_in *)&ro->ro_dst;
 101         struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
 102         struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
 103         struct ip iphdr;        /* capsule IP header, host byte ordered */
 104         int proto, error;
 105         u_int8_t tos;
 106
 107         if (sin_src == NULL || sin_dst == NULL ||
 108             sin_src->sin_family != AF_INET ||
 109             sin_dst->sin_family != AF_INET) {
 110                 m_freem(m);
 111                 return EAFNOSUPPORT;
 112         }
 113
 114         switch (family) {
 115 #ifdef INET
 116         case AF_INET:
 117             {
 118                 struct ip *ip;
 119
 120                 proto = IPPROTO_IPV4;
 121                 if (m->m_len < sizeof *ip) {
 122                         m = m_pullup(m, sizeof *ip);
 123                         if (!m)
 124                                 return ENOBUFS;
 125                 }
 126                 ip = mtod(m, struct ip *);
 127                 tos = ip->ip_tos;
 128                 break;
 129             }
 130 #endif
 131 #ifdef INET6
 132         case AF_INET6:
 133             {
 134                 struct ip6_hdr *ip6;
 135                 proto = IPPROTO_IPV6;
 136                 if (m->m_len < sizeof *ip6) {
 137                         m = m_pullup(m, sizeof *ip6);
 138                         if (!m)
 139                                 return ENOBUFS;
 140                 }
 141                 ip6 = mtod(m, struct ip6_hdr *);
 142                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 143                 break;
 144             }
 145 #endif
 146         default:
 147 #ifdef DEBUG
 148                 kprintf("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_NOWAIT);
 175         if (m && m->m_len < sizeof(struct ip))
 176                 m = m_pullup(m, sizeof(struct ip));
 177         if (m == NULL) {
 178                 kprintf("ENOBUFS in in_gif_output %d\n", __LINE__);
 179                 return ENOBUFS;
 180         }
 181         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 182
 183         if (dst->sin_family != sin_dst->sin_family ||
 184             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
 185                 /* cache route doesn't match */
 186                 dst->sin_family = sin_dst->sin_family;
 187                 dst->sin_len = sizeof(struct sockaddr_in);
 188                 dst->sin_addr = sin_dst->sin_addr;
 189                 if (ro->ro_rt != NULL) {
 190                         RTFREE(ro->ro_rt);
 191                         ro->ro_rt = NULL;
 192                 }
 193 #if 0
 194                 sc->gif_if.if_mtu = GIF_MTU;
 195 #endif
 196         }
 197
 198         if (ro->ro_rt == NULL) {
 199                 rtalloc(ro);
 200                 if (ro->ro_rt == NULL) {
 201                         m_freem(m);
 202                         return ENETUNREACH;
 203                 }
 204
 205                 /* if it constitutes infinite encapsulation, punt. */
 206                 if (ro->ro_rt->rt_ifp == ifp) {
 207                         m_freem(m);
 208                         return ENETUNREACH;     /* XXX */
 209                 }
 210 #if 0
 211                 ifp->if_mtu = ro->ro_rt->rt_ifp->if_mtu - sizeof(struct ip);
 212 #endif
 213         }
 214
 215         error = ip_output(m, NULL, ro, 0, NULL, NULL);
 216         return(error);
 217 }
 218
 219 int
 220 in_gif_input(struct mbuf **mp, int *offp, int proto)
 221 {
 222         struct mbuf *m = *mp;
 223         struct ifnet *gifp = NULL;
 224         struct ip *ip;
 225         int af;
 226         u_int8_t otos;
 227         int off;
 228
 229         off = *offp;
 230         *mp = NULL;
 231
 232         ip = mtod(m, struct ip *);
 233
 234         gifp = (struct ifnet *)encap_getarg(m);
 235
 236         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 237                 m_freem(m);
 238                 ipstat.ips_nogif++;
 239                 return(IPPROTO_DONE);
 240         }
 241
 242         otos = ip->ip_tos;
 243         m_adj(m, off);
 244
 245         switch (proto) {
 246 #ifdef INET
 247         case IPPROTO_IPV4:
 248             {
 249                 struct ip *ip;
 250                 af = AF_INET;
 251                 if (m->m_len < sizeof *ip) {
 252                         m = m_pullup(m, sizeof *ip);
 253                         if (!m)
 254                                 return(IPPROTO_DONE);
 255                 }
 256                 ip = mtod(m, struct ip *);
 257                 if (gifp->if_flags & IFF_LINK1)
 258                         ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
 259                 else
 260                         ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 261                 break;
 262             }
 263 #endif
 264 #ifdef INET6
 265         case IPPROTO_IPV6:
 266             {
 267                 struct ip6_hdr *ip6;
 268                 u_int8_t itos;
 269                 af = AF_INET6;
 270                 if (m->m_len < sizeof *ip6) {
 271                         m = m_pullup(m, sizeof *ip6);
 272                         if (!m)
 273                                 return(IPPROTO_DONE);
 274                 }
 275                 ip6 = mtod(m, struct ip6_hdr *);
 276                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 277                 if (gifp->if_flags & IFF_LINK1)
 278                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 279                 else
 280                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 281                 ip6->ip6_flow &= ~htonl(0xff << 20);
 282                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 283                 break;
 284             }
 285 #endif /* INET6 */
 286         default:
 287                 ipstat.ips_nogif++;
 288                 m_freem(m);
 289                 return(IPPROTO_DONE);
 290         }
 291         gif_input(m, af, gifp);
 292         return(IPPROTO_DONE);
 293 }
 294
 295 /*
 296  * validate outer address.
 297  */
 298 static int
 299 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
 300 {
 301         struct sockaddr_in *src, *dst;
 302         struct in_ifaddr_container *iac;
 303
 304         src = (struct sockaddr_in *)sc->gif_psrc;
 305         dst = (struct sockaddr_in *)sc->gif_pdst;
 306
 307         /* check for address match */
 308         if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
 309             dst->sin_addr.s_addr != ip->ip_src.s_addr)
 310                 return 0;
 311
 312         /* martian filters on outer source - NOT done in ip_input! */
 313         if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
 314                 return 0;
 315         switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
 316         case 0: case 127: case 255:
 317                 return 0;
 318         }
 319         /* reject packets with broadcast on source */
 320         TAILQ_FOREACH(iac, &in_ifaddrheads[mycpuid], ia_link) {
 321                 struct in_ifaddr *ia4 = iac->ia;
 322
 323                 if (!(ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST))
 324                         continue;
 325                 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
 326                         return 0;
 327         }
 328
 329         /* ingress filters on outer source */
 330         if (!(sc->gif_if.if_flags & IFF_LINK2) && ifp != NULL) {
 331                 struct sockaddr_in sin;
 332                 struct rtentry *rt;
 333
 334                 bzero(&sin, sizeof sin);
 335                 sin.sin_family = AF_INET;
 336                 sin.sin_len = sizeof(struct sockaddr_in);
 337                 sin.sin_addr = ip->ip_src;
 338                 rt = rtpurelookup((struct sockaddr *)&sin);
 339                 if (rt != NULL)
 340                         --rt->rt_refcnt;
 341                 if (rt == NULL || rt->rt_ifp != ifp) {
 342 #if 0
 343                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 344                             "due to ingress filter\n", if_name(&sc->gif_if),
 345                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
 346 #endif
 347                         return 0;
 348                 }
 349         }
 350
 351         return 32 * 2;
 352 }
 353
 354 /*
 355  * we know that we are in IFF_UP, outer address available, and outer family
 356  * matched the physical addr family.  see gif_encapcheck().
 357  */
 358 int
 359 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
 360 {
 361         struct ip ip;
 362         struct gif_softc *sc;
 363         struct ifnet *ifp;
 364
 365         /* sanity check done in caller */
 366         sc = (struct gif_softc *)arg;
 367
 368         /* LINTED const cast */
 369         m_copydata(__DECONST(struct mbuf *, m), 0, sizeof ip, &ip);
 370         ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
 371
 372         return gif_validate4(&ip, sc, ifp);
 373 }
 374
 375 int
 376 in_gif_attach(struct gif_softc *sc)
 377 {
 378         sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
 379             &in_gif_protosw, sc);
 380         if (sc->encap_cookie4 == NULL)
 381                 return EEXIST;
 382         return 0;
 383 }
 384
 385 int
 386 in_gif_detach(struct gif_softc *sc)
 387 {
 388         int error;
 389
 390         error = encap_detach(sc->encap_cookie4);
 391         if (error == 0)
 392                 sc->encap_cookie4 = NULL;
 393         return error;
 394 }
 395
 396 #endif /* INET */