ip_gre.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-NetBSD
    3  *
    4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
    5  * Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@FreeBSD.org>
    6  * All rights reserved.
    7  *
    8  * This code is derived from software contributed to The NetBSD Foundation
    9  * by Heiko W.Rupp <hwr@pilhuhn.de>
   10  *
   11  * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   24  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   25  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   26  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   32  * POSSIBILITY OF SUCH DAMAGE.
   33  *
   34  * $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/12.0/sys/netinet/ip_gre.c 336676 2018-07-24 16:35:52Z andrew $");
   39 
   40 #include "opt_inet.h"
   41 #include "opt_inet6.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/jail.h>
   45 #include <sys/systm.h>
   46 #include <sys/socket.h>
   47 #include <sys/sockio.h>
   48 #include <sys/mbuf.h>
   49 #include <sys/errno.h>
   50 #include <sys/kernel.h>
   51 #include <sys/sysctl.h>
   52 #include <sys/malloc.h>
   53 #include <sys/proc.h>
   54 
   55 #include <net/if.h>
   56 #include <net/if_var.h>
   57 #include <net/vnet.h>
   58 
   59 #include <netinet/in.h>
   60 #include <netinet/in_var.h>
   61 #include <netinet/ip.h>
   62 #include <netinet/ip_encap.h>
   63 #include <netinet/ip_var.h>
   64 
   65 #ifdef INET6
   66 #include <netinet/ip6.h>
   67 #endif
   68 
   69 #include <net/if_gre.h>
   70 
   71 #define GRE_TTL                 30
   72 VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL;
   73 #define V_ip_gre_ttl            VNET(ip_gre_ttl)
   74 SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW,
   75     &VNET_NAME(ip_gre_ttl), 0, "Default TTL value for encapsulated packets");
   76 
   77 VNET_DEFINE_STATIC(struct gre_list *, ipv4_hashtbl) = NULL;
   78 #define V_ipv4_hashtbl          VNET(ipv4_hashtbl)
   79 #define GRE_HASH(src, dst)      (V_ipv4_hashtbl[\
   80     in_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)])
   81 #define GRE_HASH_SC(sc)         GRE_HASH((sc)->gre_oip.ip_src.s_addr,\
   82     (sc)->gre_oip.ip_dst.s_addr)
   83 
   84 static uint32_t
   85 in_gre_hashval(in_addr_t src, in_addr_t dst)
   86 {
   87         uint32_t ret;
   88 
   89         ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
   90         return (fnv_32_buf(&dst, sizeof(dst), ret));
   91 }
   92 
   93 static int
   94 in_gre_checkdup(const struct gre_softc *sc, in_addr_t src, in_addr_t dst)
   95 {
   96         struct gre_softc *tmp;
   97 
   98         if (sc->gre_family == AF_INET &&
   99             sc->gre_oip.ip_src.s_addr == src &&
  100             sc->gre_oip.ip_dst.s_addr == dst)
  101                 return (EEXIST);
  102 
  103         CK_LIST_FOREACH(tmp, &GRE_HASH(src, dst), chain) {
  104                 if (tmp == sc)
  105                         continue;
  106                 if (tmp->gre_oip.ip_src.s_addr == src &&
  107                     tmp->gre_oip.ip_dst.s_addr == dst)
  108                         return (EADDRNOTAVAIL);
  109         }
  110         return (0);
  111 }
  112 
  113 static int
  114 in_gre_lookup(const struct mbuf *m, int off, int proto, void **arg)
  115 {
  116         const struct ip *ip;
  117         struct gre_softc *sc;
  118 
  119         if (V_ipv4_hashtbl == NULL)
  120                 return (0);
  121 
  122         MPASS(in_epoch(net_epoch_preempt));
  123         ip = mtod(m, const struct ip *);
  124         CK_LIST_FOREACH(sc, &GRE_HASH(ip->ip_dst.s_addr,
  125             ip->ip_src.s_addr), chain) {
  126                 /*
  127                  * This is an inbound packet, its ip_dst is source address
  128                  * in softc.
  129                  */
  130                 if (sc->gre_oip.ip_src.s_addr == ip->ip_dst.s_addr &&
  131                     sc->gre_oip.ip_dst.s_addr == ip->ip_src.s_addr) {
  132                         if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0)
  133                                 return (0);
  134                         *arg = sc;
  135                         return (ENCAP_DRV_LOOKUP);
  136                 }
  137         }
  138         return (0);
  139 }
  140 
  141 static void
  142 in_gre_attach(struct gre_softc *sc)
  143 {
  144 
  145         sc->gre_hlen = sizeof(struct greip);
  146         sc->gre_oip.ip_v = IPVERSION;
  147         sc->gre_oip.ip_hl = sizeof(struct ip) >> 2;
  148         sc->gre_oip.ip_p = IPPROTO_GRE;
  149         gre_updatehdr(sc, &sc->gre_gihdr->gi_gre);
  150         CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain);
  151 }
  152 
  153 void
  154 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value)
  155 {
  156 
  157         MPASS(cmd == GRESKEY || cmd == GRESOPTS);
  158 
  159         /* NOTE: we are protected with gre_ioctl_sx lock */
  160         MPASS(sc->gre_family == AF_INET);
  161         CK_LIST_REMOVE(sc, chain);
  162         GRE_WAIT();
  163         if (cmd == GRESKEY)
  164                 sc->gre_key = value;
  165         else
  166                 sc->gre_options = value;
  167         in_gre_attach(sc);
  168 }
  169 
  170 int
  171 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data)
  172 {
  173         struct ifreq *ifr = (struct ifreq *)data;
  174         struct sockaddr_in *dst, *src;
  175         struct ip *ip;
  176         int error;
  177 
  178         /* NOTE: we are protected with gre_ioctl_sx lock */
  179         error = EINVAL;
  180         switch (cmd) {
  181         case SIOCSIFPHYADDR:
  182                 src = &((struct in_aliasreq *)data)->ifra_addr;
  183                 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
  184 
  185                 /* sanity checks */
  186                 if (src->sin_family != dst->sin_family ||
  187                     src->sin_family != AF_INET ||
  188                     src->sin_len != dst->sin_len ||
  189                     src->sin_len != sizeof(*src))
  190                         break;
  191                 if (src->sin_addr.s_addr == INADDR_ANY ||
  192                     dst->sin_addr.s_addr == INADDR_ANY) {
  193                         error = EADDRNOTAVAIL;
  194                         break;
  195                 }
  196                 if (V_ipv4_hashtbl == NULL)
  197                         V_ipv4_hashtbl = gre_hashinit();
  198                 error = in_gre_checkdup(sc, src->sin_addr.s_addr,
  199                     dst->sin_addr.s_addr);
  200                 if (error == EADDRNOTAVAIL)
  201                         break;
  202                 if (error == EEXIST) {
  203                         /* Addresses are the same. Just return. */
  204                         error = 0;
  205                         break;
  206                 }
  207                 ip = malloc(sizeof(struct greip) + 3 * sizeof(uint32_t),
  208                     M_GRE, M_WAITOK | M_ZERO);
  209                 ip->ip_src.s_addr = src->sin_addr.s_addr;
  210                 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
  211                 if (sc->gre_family != 0) {
  212                         /* Detach existing tunnel first */
  213                         CK_LIST_REMOVE(sc, chain);
  214                         GRE_WAIT();
  215                         free(sc->gre_hdr, M_GRE);
  216                         /* XXX: should we notify about link state change? */
  217                 }
  218                 sc->gre_family = AF_INET;
  219                 sc->gre_hdr = ip;
  220                 sc->gre_oseq = 0;
  221                 sc->gre_iseq = UINT32_MAX;
  222                 in_gre_attach(sc);
  223                 break;
  224         case SIOCGIFPSRCADDR:
  225         case SIOCGIFPDSTADDR:
  226                 if (sc->gre_family != AF_INET) {
  227                         error = EADDRNOTAVAIL;
  228                         break;
  229                 }
  230                 src = (struct sockaddr_in *)&ifr->ifr_addr;
  231                 memset(src, 0, sizeof(*src));
  232                 src->sin_family = AF_INET;
  233                 src->sin_len = sizeof(*src);
  234                 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
  235                     sc->gre_oip.ip_src: sc->gre_oip.ip_dst;
  236                 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
  237                 if (error != 0)
  238                         memset(src, 0, sizeof(*src));
  239                 break;
  240         }
  241         return (error);
  242 }
  243 
  244 int
  245 in_gre_output(struct mbuf *m, int af, int hlen)
  246 {
  247         struct greip *gi;
  248 
  249         gi = mtod(m, struct greip *);
  250         switch (af) {
  251         case AF_INET:
  252                 /*
  253                  * gre_transmit() has used M_PREPEND() that doesn't guarantee
  254                  * m_data is contiguous more than hlen bytes. Use m_copydata()
  255                  * here to avoid m_pullup().
  256                  */
  257                 m_copydata(m, hlen + offsetof(struct ip, ip_tos),
  258                     sizeof(u_char), &gi->gi_ip.ip_tos);
  259                 m_copydata(m, hlen + offsetof(struct ip, ip_id),
  260                     sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id);
  261                 break;
  262 #ifdef INET6
  263         case AF_INET6:
  264                 gi->gi_ip.ip_tos = 0; /* XXX */
  265                 ip_fillid(&gi->gi_ip);
  266                 break;
  267 #endif
  268         }
  269         gi->gi_ip.ip_ttl = V_ip_gre_ttl;
  270         gi->gi_ip.ip_len = htons(m->m_pkthdr.len);
  271         return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL));
  272 }
  273 
  274 static const struct encaptab *ecookie = NULL;
  275 static const struct encap_config ipv4_encap_cfg = {
  276         .proto = IPPROTO_GRE,
  277         .min_length = sizeof(struct greip) + sizeof(struct ip),
  278         .exact_match = ENCAP_DRV_LOOKUP,
  279         .lookup = in_gre_lookup,
  280         .input = gre_input
  281 };
  282 
  283 void
  284 in_gre_init(void)
  285 {
  286 
  287         if (!IS_DEFAULT_VNET(curvnet))
  288                 return;
  289         ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
  290 }
  291 
  292 void
  293 in_gre_uninit(void)
  294 {
  295 
  296         if (IS_DEFAULT_VNET(curvnet))
  297                 ip_encap_detach(ecookie);
  298         if (V_ipv4_hashtbl != NULL)
  299                 gre_hashdestroy(V_ipv4_hashtbl);
  300 }
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FreeBSD/Linux Kernel Cross Reference sys/netinet/ip_gre.c

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