bsd/netinet/in_gif.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*      $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ */
  23
  24 /*
  25  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  26  * All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. Neither the name of the project nor the names of its contributors
  37  *    may be used to endorse or promote products derived from this software
  38  *    without specific prior written permission.
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  */
  52
  53
  54 #include <sys/param.h>
  55 #include <sys/systm.h>
  56 #include <sys/socket.h>
  57 #include <sys/sockio.h>
  58 #include <sys/mbuf.h>
  59 #include <sys/errno.h>
  60 #include <sys/kernel.h>
  61 #include <sys/sysctl.h>
  62
  63 #include <sys/malloc.h>
  64
  65 #include <net/if.h>
  66 #include <net/route.h>
  67
  68 #include <netinet/in.h>
  69 #include <netinet/in_systm.h>
  70 #include <netinet/ip.h>
  71 #include <netinet/ip_var.h>
  72 #include <netinet/in_gif.h>
  73 #include <netinet/in_var.h>
  74 #include <netinet/ip_encap.h>
  75 #include <netinet/ip_ecn.h>
  76
  77 #if INET6
  78 #include <netinet/ip6.h>
  79 #endif
  80
  81 #if MROUTING
  82 #include <netinet/ip_mroute.h>
  83 #endif /* MROUTING */
  84
  85 #include <net/if_gif.h>
  86
  87 #include <net/net_osdep.h>
  88
  89 int ip_gif_ttl = GIF_TTL;
  90 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
  91         &ip_gif_ttl,    0, "");
  92
  93 int
  94 in_gif_output(
  95         struct ifnet    *ifp,
  96         int             family,
  97         struct mbuf     *m,
  98         struct rtentry *rt)
  99 {
 100         struct gif_softc *sc = (struct gif_softc*)ifp;
 101         struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
 102         struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
 103         struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
 104         struct ip iphdr;        /* capsule IP header, host byte ordered */
 105         int proto, error;
 106         u_int8_t tos;
 107
 108         if (sin_src == NULL || sin_dst == NULL ||
 109             sin_src->sin_family != AF_INET ||
 110             sin_dst->sin_family != AF_INET) {
 111                 m_freem(m);
 112                 return EAFNOSUPPORT;
 113         }
 114
 115         switch (family) {
 116 #if INET
 117         case AF_INET:
 118             {
 119                 struct ip *ip;
 120
 121                 proto = IPPROTO_IPV4;
 122                 if (m->m_len < sizeof(*ip)) {
 123                         m = m_pullup(m, sizeof(*ip));
 124                         if (!m)
 125                                 return ENOBUFS;
 126                 }
 127                 ip = mtod(m, struct ip *);
 128                 tos = ip->ip_tos;
 129                 break;
 130             }
 131 #endif /*INET*/
 132 #if INET6
 133         case AF_INET6:
 134             {
 135                 struct ip6_hdr *ip6;
 136                 proto = IPPROTO_IPV6;
 137                 if (m->m_len < sizeof(*ip6)) {
 138                         m = m_pullup(m, sizeof(*ip6));
 139                         if (!m)
 140                                 return ENOBUFS;
 141                 }
 142                 ip6 = mtod(m, struct ip6_hdr *);
 143                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 144                 break;
 145             }
 146 #endif /*INET6*/
 147         default:
 148 #if DEBUG
 149                 printf("in_gif_output: warning: unknown family %d passed\n",
 150                         family);
 151 #endif
 152                 m_freem(m);
 153                 return EAFNOSUPPORT;
 154         }
 155
 156         bzero(&iphdr, sizeof(iphdr));
 157         iphdr.ip_src = sin_src->sin_addr;
 158         /* bidirectional configured tunnel mode */
 159         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 160                 iphdr.ip_dst = sin_dst->sin_addr;
 161         else {
 162                 m_freem(m);
 163                 return ENETUNREACH;
 164         }
 165         iphdr.ip_p = proto;
 166         /* version will be set in ip_output() */
 167         iphdr.ip_ttl = ip_gif_ttl;
 168         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 169         if (ifp->if_flags & IFF_LINK1)
 170                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
 171         else
 172                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 173
 174         /* prepend new IP header */
 175         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 176         if (m && m->m_len < sizeof(struct ip))
 177                 m = m_pullup(m, sizeof(struct ip));
 178         if (m == NULL) {
 179                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 180                 return ENOBUFS;
 181         }
 182         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 183
 184         if (dst->sin_family != sin_dst->sin_family ||
 185             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
 186                 /* cache route doesn't match */
 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 #if 0
 195                 sc->gif_if.if_mtu = GIF_MTU;
 196 #endif
 197         }
 198
 199         if (sc->gif_ro.ro_rt == NULL) {
 200                 rtalloc(&sc->gif_ro);
 201                 if (sc->gif_ro.ro_rt == NULL) {
 202                         m_freem(m);
 203                         return ENETUNREACH;
 204                 }
 205
 206                 /* if it constitutes infinite encapsulation, punt. */
 207                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 208                         m_freem(m);
 209                         return ENETUNREACH;     /*XXX*/
 210                 }
 211 #if 0
 212                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 213                         - sizeof(struct ip);
 214 #endif
 215         }
 216
 217         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL);
 218         return(error);
 219 }
 220
 221 void
 222 in_gif_input(m, off)
 223         struct mbuf *m;
 224         int off;
 225 {
 226         struct ifnet *gifp = NULL;
 227         struct ip *ip;
 228         int i, af, proto;
 229         u_int8_t otos;
 230
 231         ip = mtod(m, struct ip *);
 232         proto = ip->ip_p;
 233
 234
 235         gifp = (struct ifnet *)encap_getarg(m);
 236
 237         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 238                 m_freem(m);
 239                 ipstat.ips_nogif++;
 240                 return;
 241         }
 242
 243         otos = ip->ip_tos;
 244         m_adj(m, off);
 245
 246         switch (proto) {
 247 #if INET
 248         case IPPROTO_IPV4:
 249             {
 250                 struct ip *ip;
 251                 af = AF_INET;
 252                 if (m->m_len < sizeof(*ip)) {
 253                         m = m_pullup(m, sizeof(*ip));
 254                         if (!m)
 255                                 return;
 256                 }
 257                 ip = mtod(m, struct ip *);
 258                 if (gifp->if_flags & IFF_LINK1)
 259                         ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
 260                 else
 261                         ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 262                 break;
 263             }
 264 #endif
 265 #if INET6
 266         case IPPROTO_IPV6:
 267             {
 268                 struct ip6_hdr *ip6;
 269                 u_int8_t itos;
 270                 af = AF_INET6;
 271                 if (m->m_len < sizeof(*ip6)) {
 272                         m = m_pullup(m, sizeof(*ip6));
 273                         if (!m)
 274                                 return;
 275                 }
 276                 ip6 = mtod(m, struct ip6_hdr *);
 277                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 278                 if (gifp->if_flags & IFF_LINK1)
 279                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 280                 else
 281                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 282                 ip6->ip6_flow &= ~htonl(0xff << 20);
 283                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 284                 break;
 285             }
 286 #endif /* INET6 */
 287         default:
 288                 ipstat.ips_nogif++;
 289                 m_freem(m);
 290                 return;
 291         }
 292 #ifdef __APPLE__
 293         /* Should we free m if dlil_input returns an error? */
 294         if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for dlil to route it correctly */
 295                 m->m_pkthdr.rcvif = gifp;
 296         dlil_input_packet(gifp, m, NULL);
 297 #else
 298         gif_input(m, af, gifp);
 299 #endif
 300         return;
 301 }
 302
 303 /*
 304  * we know that we are in IFF_UP, outer address available, and outer family
 305  * matched the physical addr family.  see gif_encapcheck().
 306  */
 307 int
 308 gif_encapcheck4(m, off, proto, arg)
 309         const struct mbuf *m;
 310         int off;
 311         int proto;
 312         void *arg;
 313 {
 314         struct ip ip;
 315         struct gif_softc *sc;
 316         struct sockaddr_in *src, *dst;
 317         int addrmatch;
 318         struct in_ifaddr *ia4;
 319
 320         /* sanity check done in caller */
 321         sc = (struct gif_softc *)arg;
 322         src = (struct sockaddr_in *)sc->gif_psrc;
 323         dst = (struct sockaddr_in *)sc->gif_pdst;
 324
 325         /* LINTED const cast */
 326         m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
 327
 328         /* check for address match */
 329         addrmatch = 0;
 330         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 331                 addrmatch |= 1;
 332         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 333                 addrmatch |= 2;
 334         if (addrmatch != 3)
 335                 return 0;
 336
 337         /* martian filters on outer source - NOT done in ip_input! */
 338         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 339                 return 0;
 340         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 341         case 0: case 127: case 255:
 342                 return 0;
 343         }
 344         /* reject packets with broadcast on source */
 345         lck_mtx_lock(rt_mtx);
 346         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 347              ia4 = TAILQ_NEXT(ia4, ia_link))
 348         {
 349                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
 350                         continue;
 351                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 352                         lck_mtx_unlock(rt_mtx);
 353                         return 0;
 354                 }
 355         }
 356         lck_mtx_unlock(rt_mtx);
 357
 358         /* ingress filters on outer source */
 359         if ((sc->gif_if.if_flags & IFF_LINK2) == 0 &&
 360             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 361                 struct sockaddr_in sin;
 362                 struct rtentry *rt;
 363
 364                 bzero(&sin, sizeof(sin));
 365                 sin.sin_family = AF_INET;
 366                 sin.sin_len = sizeof(struct sockaddr_in);
 367                 sin.sin_addr = ip.ip_src;
 368                 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
 369                 if (!rt || rt->rt_ifp != m->m_pkthdr.rcvif) {
 370 #if 0
 371                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 372                             "due to ingress filter\n", if_name(&sc->gif_if),
 373                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
 374 #endif
 375                         if (rt)
 376                                 rtfree(rt);
 377                         return 0;
 378                 }
 379                 rtfree(rt);
 380         }
 381
 382         return 32 * 2;
 383 }