sys/netinet/in_gif.c

   1 /*      $NetBSD: in_gif.c,v 1.59 2008/04/12 05:58:22 thorpej 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 1.59 2008/04/12 05:58:22 thorpej 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 rtentry *rt;
  94         struct gif_softc *sc = ifp->if_softc;
  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         union {
 101                 struct sockaddr         dst;
 102                 struct sockaddr_in      dst4;
 103         } u;
 104
 105         if (sin_src == NULL || sin_dst == NULL ||
 106             sin_src->sin_family != AF_INET ||
 107             sin_dst->sin_family != AF_INET) {
 108                 m_freem(m);
 109                 return EAFNOSUPPORT;
 110         }
 111
 112         switch (family) {
 113 #ifdef INET
 114         case AF_INET:
 115             {
 116                 const struct ip *ip;
 117
 118                 proto = IPPROTO_IPV4;
 119                 if (m->m_len < sizeof(*ip)) {
 120                         m = m_pullup(m, sizeof(*ip));
 121                         if (m == NULL)
 122                                 return ENOBUFS;
 123                 }
 124                 ip = mtod(m, const struct ip *);
 125                 tos = ip->ip_tos;
 126                 break;
 127             }
 128 #endif /* INET */
 129 #ifdef INET6
 130         case AF_INET6:
 131             {
 132                 const struct ip6_hdr *ip6;
 133                 proto = IPPROTO_IPV6;
 134                 if (m->m_len < sizeof(*ip6)) {
 135                         m = m_pullup(m, sizeof(*ip6));
 136                         if (!m)
 137                                 return ENOBUFS;
 138                 }
 139                 ip6 = mtod(m, const struct ip6_hdr *);
 140                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 141                 break;
 142             }
 143 #endif /* INET6 */
 144 #ifdef ISO
 145         case AF_ISO:
 146                 proto = IPPROTO_EON;
 147                 tos = 0;
 148                 break;
 149 #endif
 150         default:
 151 #ifdef DEBUG
 152                 printf("in_gif_output: warning: unknown family %d passed\n",
 153                         family);
 154 #endif
 155                 m_freem(m);
 156                 return EAFNOSUPPORT;
 157         }
 158
 159         memset(&iphdr, 0, sizeof(iphdr));
 160         iphdr.ip_src = sin_src->sin_addr;
 161         /* bidirectional configured tunnel mode */
 162         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 163                 iphdr.ip_dst = sin_dst->sin_addr;
 164         else {
 165                 m_freem(m);
 166                 return ENETUNREACH;
 167         }
 168         iphdr.ip_p = proto;
 169         /* version will be set in ip_output() */
 170         iphdr.ip_ttl = ip_gif_ttl;
 171         iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
 172         if (ifp->if_flags & IFF_LINK1)
 173                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
 174         else
 175                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 176
 177         /* prepend new IP header */
 178         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 179         /* XXX Is m_pullup really necessary after M_PREPEND? */
 180         if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip)))
 181                 m = m_pullup(m, sizeof(struct ip));
 182         if (m == NULL)
 183                 return ENOBUFS;
 184         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 185
 186         sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0);
 187         if ((rt = rtcache_lookup(&sc->gif_ro, &u.dst)) == NULL) {
 188                 m_freem(m);
 189                 return ENETUNREACH;
 190         }
 191
 192         /* If the route constitutes infinite encapsulation, punt. */
 193         if (rt->rt_ifp == ifp) {
 194                 rtcache_free(&sc->gif_ro);
 195                 m_freem(m);
 196                 return ENETUNREACH;     /*XXX*/
 197         }
 198
 199         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
 200         return (error);
 201 }
 202
 203 void
 204 in_gif_input(struct mbuf *m, ...)
 205 {
 206         int off, proto;
 207         struct ifnet *gifp = NULL;
 208         const struct ip *ip;
 209         va_list ap;
 210         int af;
 211         u_int8_t otos;
 212
 213         va_start(ap, m);
 214         off = va_arg(ap, int);
 215         proto = va_arg(ap, int);
 216         va_end(ap);
 217
 218         ip = mtod(m, const struct ip *);
 219
 220         gifp = (struct ifnet *)encap_getarg(m);
 221
 222         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 223                 m_freem(m);
 224                 ip_statinc(IP_STAT_NOGIF);
 225                 return;
 226         }
 227 #ifndef GIF_ENCAPCHECK
 228         if (!gif_validate4(ip, gifp->if_softc, m->m_pkthdr.rcvif)) {
 229                 m_freem(m);
 230                 ip_statinc(IP_STAT_NOGIF);
 231                 return;
 232         }
 233 #endif
 234
 235         otos = ip->ip_tos;
 236         m_adj(m, off);
 237
 238         switch (proto) {
 239 #ifdef INET
 240         case IPPROTO_IPV4:
 241             {
 242                 struct ip *xip;
 243                 af = AF_INET;
 244                 if (M_UNWRITABLE(m, sizeof(*xip))) {
 245                         if ((m = m_pullup(m, sizeof(*xip))) == NULL)
 246                                 return;
 247                 }
 248                 xip = mtod(m, struct ip *);
 249                 if (gifp->if_flags & IFF_LINK1)
 250                         ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos);
 251                 else
 252                         ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos);
 253                 break;
 254             }
 255 #endif
 256 #ifdef INET6
 257         case IPPROTO_IPV6:
 258             {
 259                 struct ip6_hdr *ip6;
 260                 u_int8_t itos;
 261                 af = AF_INET6;
 262                 if (M_UNWRITABLE(m, sizeof(*ip6))) {
 263                         if ((m = m_pullup(m, sizeof(*ip6))) == NULL)
 264                                 return;
 265                 }
 266                 ip6 = mtod(m, struct ip6_hdr *);
 267                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 268                 if (gifp->if_flags & IFF_LINK1)
 269                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 270                 else
 271                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 272                 ip6->ip6_flow &= ~htonl(0xff << 20);
 273                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 274                 break;
 275             }
 276 #endif /* INET6 */
 277 #ifdef ISO
 278         case IPPROTO_EON:
 279                 af = AF_ISO;
 280                 break;
 281 #endif
 282         default:
 283                 ip_statinc(IP_STAT_NOGIF);
 284                 m_freem(m);
 285                 return;
 286         }
 287         gif_input(m, af, gifp);
 288         return;
 289 }
 290
 291 /*
 292  * validate outer address.
 293  */
 294 static int
 295 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
 296 {
 297         struct sockaddr_in *src, *dst;
 298         struct in_ifaddr *ia4;
 299
 300         src = (struct sockaddr_in *)sc->gif_psrc;
 301         dst = (struct sockaddr_in *)sc->gif_pdst;
 302
 303         /* check for address match */
 304         if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
 305             dst->sin_addr.s_addr != ip->ip_src.s_addr)
 306                 return 0;
 307
 308         /* martian filters on outer source - NOT done in ip_input! */
 309         if (IN_MULTICAST(ip->ip_src.s_addr))
 310                 return 0;
 311         switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
 312         case 0: case 127: case 255:
 313                 return 0;
 314         }
 315         /* reject packets with broadcast on source */
 316         TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
 317                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
 318                         continue;
 319                 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
 320                         return 0;
 321         }
 322
 323         /* ingress filters on outer source */
 324         if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
 325                 union {
 326                         struct sockaddr sa;
 327                         struct sockaddr_in sin;
 328                 } u;
 329                 struct rtentry *rt;
 330
 331                 sockaddr_in_init(&u.sin, &ip->ip_src, 0);
 332                 rt = rtalloc1(&u.sa, 0);
 333                 if (rt == NULL || rt->rt_ifp != ifp) {
 334 #if 0
 335                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 336                             "due to ingress filter\n", if_name(&sc->gif_if),
 337                             (u_int32_t)ntohl(u.sin.sin_addr.s_addr));
 338 #endif
 339                         if (rt != NULL)
 340                                 rtfree(rt);
 341                         return 0;
 342                 }
 343                 rtfree(rt);
 344         }
 345
 346         return 32 * 2;
 347 }
 348
 349 #ifdef GIF_ENCAPCHECK
 350 /*
 351  * we know that we are in IFF_UP, outer address available, and outer family
 352  * matched the physical addr family.  see gif_encapcheck().
 353  */
 354 int
 355 gif_encapcheck4(struct mbuf *m, int off, int proto, void *arg)
 356 {
 357         struct ip ip;
 358         struct gif_softc *sc;
 359         struct ifnet *ifp;
 360
 361         /* sanity check done in caller */
 362         sc = arg;
 363
 364         m_copydata(m, 0, sizeof(ip), &ip);
 365         ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
 366
 367         return gif_validate4(&ip, sc, ifp);
 368 }
 369 #endif
 370
 371 int
 372 in_gif_attach(struct gif_softc *sc)
 373 {
 374 #ifndef GIF_ENCAPCHECK
 375         struct sockaddr_in mask4;
 376
 377         memset(&mask4, 0, sizeof(mask4));
 378         mask4.sin_len = sizeof(struct sockaddr_in);
 379         mask4.sin_addr.s_addr = ~0;
 380
 381         if (!sc->gif_psrc || !sc->gif_pdst)
 382                 return EINVAL;
 383         sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
 384             (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
 385             (const struct protosw *)&in_gif_protosw, sc);
 386 #else
 387         sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
 388             &in_gif_protosw, sc);
 389 #endif
 390         if (sc->encap_cookie4 == NULL)
 391                 return EEXIST;
 392         return 0;
 393 }
 394
 395 int
 396 in_gif_detach(struct gif_softc *sc)
 397 {
 398         int error;
 399
 400         error = encap_detach(sc->encap_cookie4);
 401         if (error == 0)
 402                 sc->encap_cookie4 = NULL;
 403
 404         rtcache_free(&sc->gif_ro);
 405
 406         return error;
 407 }