1 /* $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $ */ 2 /* $FreeBSD$ */ 3 4 /*- 5 * Copyright (c) 1998 The NetBSD Foundation, Inc. 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 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the NetBSD 24 * Foundation, Inc. and its contributors. 25 * 4. Neither the name of The NetBSD Foundation nor the names of its 26 * contributors may be used to endorse or promote products derived 27 * from this software without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 39 * POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 /* 43 * deencapsulate tunneled packets and send them on 44 * output half is in net/if_gre.[ch] 45 * This currently handles IPPROTO_GRE, IPPROTO_MOBILE 46 */ 47 48 #include "opt_inet.h" 49 #include "opt_atalk.h" 50 #include "opt_inet6.h" 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/mbuf.h> 55 #include <sys/socket.h> 56 #include <sys/socketvar.h> 57 #include <sys/protosw.h> 58 #include <sys/errno.h> 59 #include <sys/time.h> 60 #include <sys/kernel.h> 61 #include <sys/syslog.h> 62 #include <net/bpf.h> 63 #include <net/ethernet.h> 64 #include <net/if.h> 65 #include <net/netisr.h> 66 #include <net/route.h> 67 #include <net/raw_cb.h> 68 69 #ifdef INET 70 #include <netinet/in.h> 71 #include <netinet/in_var.h> 72 #include <netinet/in_systm.h> 73 #include <netinet/ip.h> 74 #include <netinet/ip_var.h> 75 #include <netinet/ip_gre.h> 76 #include <machine/in_cksum.h> 77 #else 78 #error ip_gre input without IP? 79 #endif 80 81 #ifdef NETATALK 82 #include <netatalk/at.h> 83 #include <netatalk/at_var.h> 84 #include <netatalk/at_extern.h> 85 #endif 86 87 /* Needs IP headers. */ 88 #include <net/if_gre.h> 89 90 #include <machine/stdarg.h> 91 92 #if 1 93 void gre_inet_ntoa(struct in_addr in); /* XXX */ 94 #endif 95 96 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t); 97 98 static struct mbuf *gre_input2(struct mbuf *, int, u_char); 99 100 /* 101 * De-encapsulate a packet and feed it back through ip input (this 102 * routine is called whenever IP gets a packet with proto type 103 * IPPROTO_GRE and a local destination address). 104 * This really is simple 105 */ 106 void 107 gre_input(struct mbuf *m, int off) 108 { 109 int proto; 110 111 proto = (mtod(m, struct ip *))->ip_p; 112 113 m = gre_input2(m, off, proto); 114 115 /* 116 * If no matching tunnel that is up is found. We inject 117 * the mbuf to raw ip socket to see if anyone picks it up. 118 */ 119 if (m != NULL) 120 rip_input(m, off); 121 } 122 123 /* 124 * Decapsulate. Does the real work and is called from gre_input() 125 * (above). Returns an mbuf back if packet is not yet processed, 126 * and NULL if it needs no further processing. proto is the protocol 127 * number of the "calling" foo_input() routine. 128 */ 129 static struct mbuf * 130 gre_input2(struct mbuf *m ,int hlen, u_char proto) 131 { 132 struct greip *gip; 133 int isr; 134 struct gre_softc *sc; 135 u_int16_t flags; 136 u_int32_t af; 137 138 if ((sc = gre_lookup(m, proto)) == NULL) { 139 /* No matching tunnel or tunnel is down. */ 140 return (m); 141 } 142 143 if (m->m_len < sizeof(*gip)) { 144 m = m_pullup(m, sizeof(*gip)); 145 if (m == NULL) 146 return (NULL); 147 } 148 gip = mtod(m, struct greip *); 149 150 GRE2IFP(sc)->if_ipackets++; 151 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 152 153 switch (proto) { 154 case IPPROTO_GRE: 155 hlen += sizeof(struct gre_h); 156 157 /* process GRE flags as packet can be of variable len */ 158 flags = ntohs(gip->gi_flags); 159 160 /* Checksum & Offset are present */ 161 if ((flags & GRE_CP) | (flags & GRE_RP)) 162 hlen += 4; 163 /* We don't support routing fields (variable length) */ 164 if (flags & GRE_RP) 165 return (m); 166 if (flags & GRE_KP) 167 hlen += 4; 168 if (flags & GRE_SP) 169 hlen += 4; 170 171 switch (ntohs(gip->gi_ptype)) { /* ethertypes */ 172 case WCCP_PROTOCOL_TYPE: 173 if (sc->wccp_ver == WCCP_V2) 174 hlen += 4; 175 /* FALLTHROUGH */ 176 case ETHERTYPE_IP: /* shouldn't need a schednetisr(), */ 177 isr = NETISR_IP;/* as we are in ip_input */ 178 af = AF_INET; 179 break; 180 #ifdef INET6 181 case ETHERTYPE_IPV6: 182 isr = NETISR_IPV6; 183 af = AF_INET6; 184 break; 185 #endif 186 #ifdef NETATALK 187 case ETHERTYPE_ATALK: 188 isr = NETISR_ATALK1; 189 af = AF_APPLETALK; 190 break; 191 #endif 192 default: 193 /* Others not yet supported. */ 194 return (m); 195 } 196 break; 197 default: 198 /* Others not yet supported. */ 199 return (m); 200 } 201 202 if (hlen > m->m_pkthdr.len) { 203 m_freem(m); 204 return (NULL); 205 } 206 /* Unlike NetBSD, in FreeBSD m_adj() adjusts m->m_pkthdr.len as well */ 207 m_adj(m, hlen); 208 209 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) { 210 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 211 } 212 213 m->m_pkthdr.rcvif = GRE2IFP(sc); 214 215 netisr_dispatch(isr, m); 216 217 /* Packet is done, no further processing needed. */ 218 return (NULL); 219 } 220 221 /* 222 * input routine for IPPRPOTO_MOBILE 223 * This is a little bit diffrent from the other modes, as the 224 * encapsulating header was not prepended, but instead inserted 225 * between IP header and payload 226 */ 227 228 void 229 gre_mobile_input(struct mbuf *m, int hlen) 230 { 231 struct ip *ip; 232 struct mobip_h *mip; 233 struct gre_softc *sc; 234 int msiz; 235 236 if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) { 237 /* No matching tunnel or tunnel is down. */ 238 m_freem(m); 239 return; 240 } 241 242 if (m->m_len < sizeof(*mip)) { 243 m = m_pullup(m, sizeof(*mip)); 244 if (m == NULL) 245 return; 246 } 247 ip = mtod(m, struct ip *); 248 mip = mtod(m, struct mobip_h *); 249 250 GRE2IFP(sc)->if_ipackets++; 251 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 252 253 if (ntohs(mip->mh.proto) & MOB_H_SBIT) { 254 msiz = MOB_H_SIZ_L; 255 mip->mi.ip_src.s_addr = mip->mh.osrc; 256 } else 257 msiz = MOB_H_SIZ_S; 258 259 if (m->m_len < (ip->ip_hl << 2) + msiz) { 260 m = m_pullup(m, (ip->ip_hl << 2) + msiz); 261 if (m == NULL) 262 return; 263 ip = mtod(m, struct ip *); 264 mip = mtod(m, struct mobip_h *); 265 } 266 267 mip->mi.ip_dst.s_addr = mip->mh.odst; 268 mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8); 269 270 if (gre_in_cksum((u_int16_t *)&mip->mh, msiz) != 0) { 271 m_freem(m); 272 return; 273 } 274 275 bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) + 276 (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2)); 277 m->m_len -= msiz; 278 m->m_pkthdr.len -= msiz; 279 280 /* 281 * On FreeBSD, rip_input() supplies us with ip->ip_len 282 * already converted into host byteorder and also decreases 283 * it by the lengh of IP header, however, ip_input() expects 284 * that this field is in the original format (network byteorder 285 * and full size of IP packet), so that adjust accordingly. 286 */ 287 ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz); 288 289 ip->ip_sum = 0; 290 ip->ip_sum = in_cksum(m, (ip->ip_hl << 2)); 291 292 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) { 293 u_int32_t af = AF_INET; 294 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 295 } 296 297 m->m_pkthdr.rcvif = GRE2IFP(sc); 298 299 netisr_dispatch(NETISR_IP, m); 300 } 301 302 /* 303 * Find the gre interface associated with our src/dst/proto set. 304 * 305 * XXXRW: Need some sort of drain/refcount mechanism so that the softc 306 * reference remains valid after it's returned from gre_lookup(). Right 307 * now, I'm thinking it should be reference-counted with a gre_dropref() 308 * when the caller is done with the softc. This is complicated by how 309 * to handle destroying the gre softc; probably using a gre_drain() in 310 * in_gre.c during destroy. 311 */ 312 static struct gre_softc * 313 gre_lookup(struct mbuf *m, u_int8_t proto) 314 { 315 struct ip *ip = mtod(m, struct ip *); 316 struct gre_softc *sc; 317 318 mtx_lock(&gre_mtx); 319 for (sc = LIST_FIRST(&gre_softc_list); sc != NULL; 320 sc = LIST_NEXT(sc, sc_list)) { 321 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) && 322 (sc->g_src.s_addr == ip->ip_dst.s_addr) && 323 (sc->g_proto == proto) && 324 ((GRE2IFP(sc)->if_flags & IFF_UP) != 0)) { 325 mtx_unlock(&gre_mtx); 326 return (sc); 327 } 328 } 329 mtx_unlock(&gre_mtx); 330 331 return (NULL); 332 } 333