1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include "opt_inet.h" 38 #include "opt_inet6.h" 39 40 #include <sys/param.h> 41 #include <sys/lock.h> 42 #include <sys/rmlock.h> 43 #include <sys/systm.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/sysctl.h> 50 #include <sys/malloc.h> 51 52 #include <net/if.h> 53 #include <net/if_var.h> 54 #include <net/route.h> 55 #include <net/vnet.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_var.h> 61 #include <netinet/in_var.h> 62 #include <netinet/ip_encap.h> 63 #include <netinet/ip_ecn.h> 64 #include <netinet/in_fib.h> 65 66 #ifdef INET6 67 #include <netinet/ip6.h> 68 #endif 69 70 #include <net/if_gif.h> 71 72 #define GIF_TTL 30 73 static VNET_DEFINE(int, ip_gif_ttl) = GIF_TTL; 74 #define V_ip_gif_ttl VNET(ip_gif_ttl) 75 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW, 76 &VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets"); 77 78 int 79 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn) 80 { 81 GIF_RLOCK_TRACKER; 82 struct gif_softc *sc = ifp->if_softc; 83 struct ip *ip; 84 int len; 85 86 /* prepend new IP header */ 87 len = sizeof(struct ip); 88 #ifndef __NO_STRICT_ALIGNMENT 89 if (proto == IPPROTO_ETHERIP) 90 len += ETHERIP_ALIGN; 91 #endif 92 M_PREPEND(m, len, M_NOWAIT); 93 if (m == NULL) 94 return (ENOBUFS); 95 #ifndef __NO_STRICT_ALIGNMENT 96 if (proto == IPPROTO_ETHERIP) { 97 len = mtod(m, vm_offset_t) & 3; 98 KASSERT(len == 0 || len == ETHERIP_ALIGN, 99 ("in_gif_output: unexpected misalignment")); 100 m->m_data += len; 101 m->m_len -= ETHERIP_ALIGN; 102 } 103 #endif 104 ip = mtod(m, struct ip *); 105 GIF_RLOCK(sc); 106 if (sc->gif_family != AF_INET) { 107 m_freem(m); 108 GIF_RUNLOCK(sc); 109 return (ENETDOWN); 110 } 111 bcopy(sc->gif_iphdr, ip, sizeof(struct ip)); 112 GIF_RUNLOCK(sc); 113 114 ip->ip_p = proto; 115 /* version will be set in ip_output() */ 116 ip->ip_ttl = V_ip_gif_ttl; 117 ip->ip_len = htons(m->m_pkthdr.len); 118 ip->ip_tos = ecn; 119 120 return (ip_output(m, NULL, NULL, 0, NULL, NULL)); 121 } 122 123 static int 124 in_gif_input(struct mbuf *m, int off, int proto, void *arg) 125 { 126 struct gif_softc *sc = arg; 127 struct ifnet *gifp; 128 struct ip *ip; 129 uint8_t ecn; 130 131 if (sc == NULL) { 132 m_freem(m); 133 KMOD_IPSTAT_INC(ips_nogif); 134 return (IPPROTO_DONE); 135 } 136 gifp = GIF2IFP(sc); 137 if ((gifp->if_flags & IFF_UP) != 0) { 138 ip = mtod(m, struct ip *); 139 ecn = ip->ip_tos; 140 m_adj(m, off); 141 gif_input(m, gifp, proto, ecn); 142 } else { 143 m_freem(m); 144 KMOD_IPSTAT_INC(ips_nogif); 145 } 146 return (IPPROTO_DONE); 147 } 148 149 /* 150 * we know that we are in IFF_UP, outer address available, and outer family 151 * matched the physical addr family. see gif_encapcheck(). 152 */ 153 int 154 in_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg) 155 { 156 const struct ip *ip; 157 struct gif_softc *sc; 158 int ret; 159 160 /* sanity check done in caller */ 161 sc = (struct gif_softc *)arg; 162 GIF_RLOCK_ASSERT(sc); 163 164 /* check for address match */ 165 ip = mtod(m, const struct ip *); 166 if (sc->gif_iphdr->ip_src.s_addr != ip->ip_dst.s_addr) 167 return (0); 168 ret = 32 + 8; /* src + proto */ 169 if (sc->gif_iphdr->ip_dst.s_addr != ip->ip_src.s_addr) { 170 if ((sc->gif_options & GIF_IGNORE_SOURCE) == 0) 171 return (0); 172 } else 173 ret += 32; 174 175 /* ingress filters on outer source */ 176 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) { 177 struct nhop4_basic nh4; 178 struct in_addr dst; 179 180 dst = ip->ip_src; 181 182 if (fib4_lookup_nh_basic(sc->gif_fibnum, dst, 0, 0, &nh4) != 0) 183 return (0); 184 185 if (nh4.nh_ifp != m->m_pkthdr.rcvif) 186 return (0); 187 } 188 return (ret); 189 } 190 191 static const struct encap_config ipv4_encap_cfg = { 192 .proto = -1, 193 .min_length = sizeof(struct ip), 194 .exact_match = (sizeof(in_addr_t) << 4) + 8, 195 .check = gif_encapcheck, 196 .input = in_gif_input 197 }; 198 199 int 200 in_gif_attach(struct gif_softc *sc) 201 { 202 203 KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL")); 204 sc->gif_ecookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK); 205 return (0); 206 } 207