in6_gif.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    5  * Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
    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  *      $KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: releng/12.0/sys/netinet6/in6_gif.c 337900 2018-08-16 09:19:06Z ae $");
   37 
   38 #include "opt_inet.h"
   39 #include "opt_inet6.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/jail.h>
   44 #include <sys/socket.h>
   45 #include <sys/sockio.h>
   46 #include <sys/mbuf.h>
   47 #include <sys/errno.h>
   48 #include <sys/kernel.h>
   49 #include <sys/syslog.h>
   50 #include <sys/sysctl.h>
   51 #include <sys/malloc.h>
   52 #include <sys/proc.h>
   53 
   54 #include <net/ethernet.h>
   55 #include <net/if.h>
   56 #include <net/if_var.h>
   57 #include <net/route.h>
   58 #include <net/vnet.h>
   59 
   60 #include <netinet/in.h>
   61 #include <netinet/in_systm.h>
   62 #ifdef INET
   63 #include <netinet/ip.h>
   64 #include <netinet/ip_ecn.h>
   65 #endif
   66 #include <netinet/ip_encap.h>
   67 #include <netinet/ip6.h>
   68 #include <netinet6/ip6_var.h>
   69 #include <netinet6/in6_var.h>
   70 #include <netinet6/scope6_var.h>
   71 #include <netinet6/ip6_ecn.h>
   72 #include <netinet6/in6_fib.h>
   73 
   74 #include <net/if_gif.h>
   75 
   76 #define GIF_HLIM        30
   77 VNET_DEFINE_STATIC(int, ip6_gif_hlim) = GIF_HLIM;
   78 #define V_ip6_gif_hlim                  VNET(ip6_gif_hlim)
   79 
   80 SYSCTL_DECL(_net_inet6_ip6);
   81 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim,
   82     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_gif_hlim), 0,
   83     "Default hop limit for encapsulated packets");
   84 
   85 /*
   86  * We keep interfaces in a hash table using src+dst as key.
   87  * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list.
   88  */
   89 VNET_DEFINE_STATIC(struct gif_list *, ipv6_hashtbl) = NULL;
   90 VNET_DEFINE_STATIC(struct gif_list, ipv6_list) = CK_LIST_HEAD_INITIALIZER();
   91 #define V_ipv6_hashtbl          VNET(ipv6_hashtbl)
   92 #define V_ipv6_list             VNET(ipv6_list)
   93 
   94 #define GIF_HASH(src, dst)      (V_ipv6_hashtbl[\
   95     in6_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
   96 #define GIF_HASH_SC(sc)         GIF_HASH(&(sc)->gif_ip6hdr->ip6_src,\
   97     &(sc)->gif_ip6hdr->ip6_dst)
   98 static uint32_t
   99 in6_gif_hashval(const struct in6_addr *src, const struct in6_addr *dst)
  100 {
  101         uint32_t ret;
  102 
  103         ret = fnv_32_buf(src, sizeof(*src), FNV1_32_INIT);
  104         return (fnv_32_buf(dst, sizeof(*dst), ret));
  105 }
  106 
  107 static int
  108 in6_gif_checkdup(const struct gif_softc *sc, const struct in6_addr *src,
  109     const struct in6_addr *dst)
  110 {
  111         struct gif_softc *tmp;
  112 
  113         if (sc->gif_family == AF_INET6 &&
  114             IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, src) &&
  115             IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, dst))
  116                 return (EEXIST);
  117 
  118         CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
  119                 if (tmp == sc)
  120                         continue;
  121                 if (IN6_ARE_ADDR_EQUAL(&tmp->gif_ip6hdr->ip6_src, src) &&
  122                     IN6_ARE_ADDR_EQUAL(&tmp->gif_ip6hdr->ip6_dst, dst))
  123                         return (EADDRNOTAVAIL);
  124         }
  125         return (0);
  126 }
  127 
  128 static void
  129 in6_gif_attach(struct gif_softc *sc)
  130 {
  131 
  132         if (sc->gif_options & GIF_IGNORE_SOURCE)
  133                 CK_LIST_INSERT_HEAD(&V_ipv6_list, sc, chain);
  134         else
  135                 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
  136 }
  137 
  138 int
  139 in6_gif_setopts(struct gif_softc *sc, u_int options)
  140 {
  141 
  142         /* NOTE: we are protected with gif_ioctl_sx lock */
  143         MPASS(sc->gif_family == AF_INET6);
  144         MPASS(sc->gif_options != options);
  145 
  146         if ((options & GIF_IGNORE_SOURCE) !=
  147             (sc->gif_options & GIF_IGNORE_SOURCE)) {
  148                 CK_LIST_REMOVE(sc, chain);
  149                 sc->gif_options = options;
  150                 in6_gif_attach(sc);
  151         }
  152         return (0);
  153 }
  154 
  155 int
  156 in6_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
  157 {
  158         struct in6_ifreq *ifr = (struct in6_ifreq *)data;
  159         struct sockaddr_in6 *dst, *src;
  160         struct ip6_hdr *ip6;
  161         int error;
  162 
  163         /* NOTE: we are protected with gif_ioctl_sx lock */
  164         error = EINVAL;
  165         switch (cmd) {
  166         case SIOCSIFPHYADDR_IN6:
  167                 src = &((struct in6_aliasreq *)data)->ifra_addr;
  168                 dst = &((struct in6_aliasreq *)data)->ifra_dstaddr;
  169 
  170                 /* sanity checks */
  171                 if (src->sin6_family != dst->sin6_family ||
  172                     src->sin6_family != AF_INET6 ||
  173                     src->sin6_len != dst->sin6_len ||
  174                     src->sin6_len != sizeof(*src))
  175                         break;
  176                 if (IN6_IS_ADDR_UNSPECIFIED(&src->sin6_addr) ||
  177                     IN6_IS_ADDR_UNSPECIFIED(&dst->sin6_addr)) {
  178                         error = EADDRNOTAVAIL;
  179                         break;
  180                 }
  181                 /*
  182                  * Check validity of the scope zone ID of the
  183                  * addresses, and convert it into the kernel
  184                  * internal form if necessary.
  185                  */
  186                 if ((error = sa6_embedscope(src, 0)) != 0 ||
  187                     (error = sa6_embedscope(dst, 0)) != 0)
  188                         break;
  189 
  190                 if (V_ipv6_hashtbl == NULL)
  191                         V_ipv6_hashtbl = gif_hashinit();
  192                 error = in6_gif_checkdup(sc, &src->sin6_addr,
  193                     &dst->sin6_addr);
  194                 if (error == EADDRNOTAVAIL)
  195                         break;
  196                 if (error == EEXIST) {
  197                         /* Addresses are the same. Just return. */
  198                         error = 0;
  199                         break;
  200                 }
  201                 ip6 = malloc(sizeof(*ip6), M_GIF, M_WAITOK | M_ZERO);
  202                 ip6->ip6_src = src->sin6_addr;
  203                 ip6->ip6_dst = dst->sin6_addr;
  204                 ip6->ip6_vfc = IPV6_VERSION;
  205                 if (sc->gif_family != 0) {
  206                         /* Detach existing tunnel first */
  207                         CK_LIST_REMOVE(sc, chain);
  208                         GIF_WAIT();
  209                         free(sc->gif_hdr, M_GIF);
  210                         /* XXX: should we notify about link state change? */
  211                 }
  212                 sc->gif_family = AF_INET6;
  213                 sc->gif_ip6hdr = ip6;
  214                 in6_gif_attach(sc);
  215                 break;
  216         case SIOCGIFPSRCADDR_IN6:
  217         case SIOCGIFPDSTADDR_IN6:
  218                 if (sc->gif_family != AF_INET6) {
  219                         error = EADDRNOTAVAIL;
  220                         break;
  221                 }
  222                 src = (struct sockaddr_in6 *)&ifr->ifr_addr;
  223                 memset(src, 0, sizeof(*src));
  224                 src->sin6_family = AF_INET6;
  225                 src->sin6_len = sizeof(*src);
  226                 src->sin6_addr = (cmd == SIOCGIFPSRCADDR_IN6) ?
  227                     sc->gif_ip6hdr->ip6_src: sc->gif_ip6hdr->ip6_dst;
  228                 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
  229                 if (error == 0)
  230                         error = sa6_recoverscope(src);
  231                 if (error != 0)
  232                         memset(src, 0, sizeof(*src));
  233                 break;
  234         }
  235         return (error);
  236 }
  237 
  238 int
  239 in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
  240 {
  241         struct gif_softc *sc = ifp->if_softc;
  242         struct ip6_hdr *ip6;
  243         int len;
  244 
  245         /* prepend new IP header */
  246         MPASS(in_epoch(net_epoch_preempt));
  247         len = sizeof(struct ip6_hdr);
  248 #ifndef __NO_STRICT_ALIGNMENT
  249         if (proto == IPPROTO_ETHERIP)
  250                 len += ETHERIP_ALIGN;
  251 #endif
  252         M_PREPEND(m, len, M_NOWAIT);
  253         if (m == NULL)
  254                 return (ENOBUFS);
  255 #ifndef __NO_STRICT_ALIGNMENT
  256         if (proto == IPPROTO_ETHERIP) {
  257                 len = mtod(m, vm_offset_t) & 3;
  258                 KASSERT(len == 0 || len == ETHERIP_ALIGN,
  259                     ("in6_gif_output: unexpected misalignment"));
  260                 m->m_data += len;
  261                 m->m_len -= ETHERIP_ALIGN;
  262         }
  263 #endif
  264 
  265         ip6 = mtod(m, struct ip6_hdr *);
  266         MPASS(sc->gif_family == AF_INET6);
  267         bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
  268 
  269         ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
  270         ip6->ip6_nxt    = proto;
  271         ip6->ip6_hlim   = V_ip6_gif_hlim;
  272         /*
  273          * force fragmentation to minimum MTU, to avoid path MTU discovery.
  274          * it is too painful to ask for resend of inner packet, to achieve
  275          * path MTU discovery for encapsulated packets.
  276          */
  277         return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
  278 }
  279 
  280 static int
  281 in6_gif_input(struct mbuf *m, int off, int proto, void *arg)
  282 {
  283         struct gif_softc *sc = arg;
  284         struct ifnet *gifp;
  285         struct ip6_hdr *ip6;
  286         uint8_t ecn;
  287 
  288         MPASS(in_epoch(net_epoch_preempt));
  289         if (sc == NULL) {
  290                 m_freem(m);
  291                 IP6STAT_INC(ip6s_nogif);
  292                 return (IPPROTO_DONE);
  293         }
  294         gifp = GIF2IFP(sc);
  295         if ((gifp->if_flags & IFF_UP) != 0) {
  296                 ip6 = mtod(m, struct ip6_hdr *);
  297                 ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  298                 m_adj(m, off);
  299                 gif_input(m, gifp, proto, ecn);
  300         } else {
  301                 m_freem(m);
  302                 IP6STAT_INC(ip6s_nogif);
  303         }
  304         return (IPPROTO_DONE);
  305 }
  306 
  307 static int
  308 in6_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
  309 {
  310         const struct ip6_hdr *ip6;
  311         struct gif_softc *sc;
  312         int ret;
  313 
  314         if (V_ipv6_hashtbl == NULL)
  315                 return (0);
  316 
  317         MPASS(in_epoch(net_epoch_preempt));
  318         /*
  319          * NOTE: it is safe to iterate without any locking here, because softc
  320          * can be reclaimed only when we are not within net_epoch_preempt
  321          * section, but ip_encap lookup+input are executed in epoch section.
  322          */
  323         ip6 = mtod(m, const struct ip6_hdr *);
  324         ret = 0;
  325         CK_LIST_FOREACH(sc, &GIF_HASH(&ip6->ip6_dst, &ip6->ip6_src), chain) {
  326                 /*
  327                  * This is an inbound packet, its ip6_dst is source address
  328                  * in softc.
  329                  */
  330                 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
  331                     &ip6->ip6_dst) &&
  332                     IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst,
  333                     &ip6->ip6_src)) {
  334                         ret = ENCAP_DRV_LOOKUP;
  335                         goto done;
  336                 }
  337         }
  338         /*
  339          * No exact match.
  340          * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
  341          */
  342         CK_LIST_FOREACH(sc, &V_ipv6_list, chain) {
  343                 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
  344                     &ip6->ip6_dst)) {
  345                         ret = 128 + 8; /* src + proto */
  346                         goto done;
  347                 }
  348         }
  349         return (0);
  350 done:
  351         if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
  352                 return (0);
  353         /* ingress filters on outer source */
  354         if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
  355                 struct nhop6_basic nh6;
  356 
  357                 if (fib6_lookup_nh_basic(sc->gif_fibnum, &ip6->ip6_src,
  358                     ntohs(in6_getscope(&ip6->ip6_src)), 0, 0, &nh6) != 0)
  359                         return (0);
  360 
  361                 if (nh6.nh_ifp != m->m_pkthdr.rcvif)
  362                         return (0);
  363         }
  364         *arg = sc;
  365         return (ret);
  366 }
  367 
  368 static struct {
  369         const struct encap_config encap;
  370         const struct encaptab *cookie;
  371 } ipv6_encap_cfg[] = {
  372 #ifdef INET
  373         {
  374                 .encap = {
  375                         .proto = IPPROTO_IPV4,
  376                         .min_length = sizeof(struct ip6_hdr) +
  377                             sizeof(struct ip),
  378                         .exact_match = ENCAP_DRV_LOOKUP,
  379                         .lookup = in6_gif_lookup,
  380                         .input = in6_gif_input
  381                 },
  382         },
  383 #endif
  384         {
  385                 .encap = {
  386                         .proto = IPPROTO_IPV6,
  387                         .min_length = 2 * sizeof(struct ip6_hdr),
  388                         .exact_match = ENCAP_DRV_LOOKUP,
  389                         .lookup = in6_gif_lookup,
  390                         .input = in6_gif_input
  391                 },
  392         },
  393         {
  394                 .encap = {
  395                         .proto = IPPROTO_ETHERIP,
  396                         .min_length = sizeof(struct ip6_hdr) +
  397                             sizeof(struct etherip_header) +
  398                             sizeof(struct ether_header),
  399                         .exact_match = ENCAP_DRV_LOOKUP,
  400                         .lookup = in6_gif_lookup,
  401                         .input = in6_gif_input
  402                 },
  403         }
  404 };
  405 
  406 void
  407 in6_gif_init(void)
  408 {
  409         int i;
  410 
  411         if (!IS_DEFAULT_VNET(curvnet))
  412                 return;
  413         for (i = 0; i < nitems(ipv6_encap_cfg); i++)
  414                 ipv6_encap_cfg[i].cookie = ip6_encap_attach(
  415                     &ipv6_encap_cfg[i].encap, NULL, M_WAITOK);
  416 }
  417 
  418 void
  419 in6_gif_uninit(void)
  420 {
  421         int i;
  422 
  423         if (IS_DEFAULT_VNET(curvnet)) {
  424                 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
  425                         ip6_encap_detach(ipv6_encap_cfg[i].cookie);
  426         }
  427         if (V_ipv6_hashtbl != NULL)
  428                 gif_hashdestroy(V_ipv6_hashtbl);
  429 }
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FreeBSD/Linux Kernel Cross Reference sys/netinet6/in6_gif.c

FreeBSD/Linux Kernel Cross Reference
sys/netinet6/in6_gif.c
