1 /* $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $ */ 2 3 /*- 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Heiko W.Rupp <hwr@pilhuhn.de> 9 * 10 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * deencapsulate tunneled packets and send them on 36 * output half is in net/if_gre.[ch] 37 * This currently handles IPPROTO_GRE, IPPROTO_MOBILE 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "opt_inet.h" 44 #include "opt_atalk.h" 45 #include "opt_inet6.h" 46 47 #include <sys/param.h> 48 #include <sys/systm.h> 49 #include <sys/mbuf.h> 50 #include <sys/socket.h> 51 #include <sys/socketvar.h> 52 #include <sys/protosw.h> 53 #include <sys/errno.h> 54 #include <sys/time.h> 55 #include <sys/kernel.h> 56 #include <sys/syslog.h> 57 #include <net/bpf.h> 58 #include <net/ethernet.h> 59 #include <net/if.h> 60 #include <net/if_var.h> 61 #include <net/netisr.h> 62 #include <net/route.h> 63 #include <net/raw_cb.h> 64 65 #ifdef INET 66 #include <netinet/in.h> 67 #include <netinet/in_var.h> 68 #include <netinet/in_systm.h> 69 #include <netinet/ip.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/ip_gre.h> 72 #include <machine/in_cksum.h> 73 #else 74 #error "ip_gre requires INET" 75 #endif 76 77 #ifdef NETATALK 78 #include <netatalk/at.h> 79 #include <netatalk/at_var.h> 80 #include <netatalk/at_extern.h> 81 #endif 82 83 /* Needs IP headers. */ 84 #include <net/if_gre.h> 85 86 #include <machine/stdarg.h> 87 88 #if 1 89 void gre_inet_ntoa(struct in_addr in); /* XXX */ 90 #endif 91 92 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t); 93 94 static struct mbuf *gre_input2(struct mbuf *, int, u_char); 95 96 /* 97 * De-encapsulate a packet and feed it back through ip input (this 98 * routine is called whenever IP gets a packet with proto type 99 * IPPROTO_GRE and a local destination address). 100 * This really is simple 101 */ 102 void 103 gre_input(struct mbuf *m, int off) 104 { 105 int proto; 106 107 proto = (mtod(m, struct ip *))->ip_p; 108 109 m = gre_input2(m, off, proto); 110 111 /* 112 * If no matching tunnel that is up is found. We inject 113 * the mbuf to raw ip socket to see if anyone picks it up. 114 */ 115 if (m != NULL) 116 rip_input(m, off); 117 } 118 119 /* 120 * Decapsulate. Does the real work and is called from gre_input() 121 * (above). Returns an mbuf back if packet is not yet processed, 122 * and NULL if it needs no further processing. proto is the protocol 123 * number of the "calling" foo_input() routine. 124 */ 125 static struct mbuf * 126 gre_input2(struct mbuf *m ,int hlen, u_char proto) 127 { 128 struct greip *gip; 129 int isr; 130 struct gre_softc *sc; 131 u_int16_t flags; 132 u_int32_t af; 133 134 if ((sc = gre_lookup(m, proto)) == NULL) { 135 /* No matching tunnel or tunnel is down. */ 136 return (m); 137 } 138 139 if (m->m_len < sizeof(*gip)) { 140 m = m_pullup(m, sizeof(*gip)); 141 if (m == NULL) 142 return (NULL); 143 } 144 gip = mtod(m, struct greip *); 145 146 GRE2IFP(sc)->if_ipackets++; 147 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 148 149 switch (proto) { 150 case IPPROTO_GRE: 151 hlen += sizeof(struct gre_h); 152 153 /* process GRE flags as packet can be of variable len */ 154 flags = ntohs(gip->gi_flags); 155 156 /* Checksum & Offset are present */ 157 if ((flags & GRE_CP) | (flags & GRE_RP)) 158 hlen += 4; 159 /* We don't support routing fields (variable length) */ 160 if (flags & GRE_RP) 161 return (m); 162 if (flags & GRE_KP) 163 hlen += 4; 164 if (flags & GRE_SP) 165 hlen += 4; 166 167 switch (ntohs(gip->gi_ptype)) { /* ethertypes */ 168 case WCCP_PROTOCOL_TYPE: 169 if (sc->wccp_ver == WCCP_V2) 170 hlen += 4; 171 /* FALLTHROUGH */ 172 case ETHERTYPE_IP: /* shouldn't need a schednetisr(), */ 173 isr = NETISR_IP;/* as we are in ip_input */ 174 af = AF_INET; 175 break; 176 #ifdef INET6 177 case ETHERTYPE_IPV6: 178 isr = NETISR_IPV6; 179 af = AF_INET6; 180 break; 181 #endif 182 #ifdef NETATALK 183 case ETHERTYPE_ATALK: 184 isr = NETISR_ATALK1; 185 af = AF_APPLETALK; 186 break; 187 #endif 188 default: 189 /* Others not yet supported. */ 190 return (m); 191 } 192 break; 193 default: 194 /* Others not yet supported. */ 195 return (m); 196 } 197 198 if (hlen > m->m_pkthdr.len) { 199 m_freem(m); 200 return (NULL); 201 } 202 /* Unlike NetBSD, in FreeBSD m_adj() adjusts m->m_pkthdr.len as well */ 203 m_adj(m, hlen); 204 205 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) { 206 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 207 } 208 209 if ((GRE2IFP(sc)->if_flags & IFF_MONITOR) != 0) { 210 m_freem(m); 211 return(NULL); 212 } 213 214 m->m_pkthdr.rcvif = GRE2IFP(sc); 215 216 netisr_queue(isr, m); 217 218 /* Packet is done, no further processing needed. */ 219 return (NULL); 220 } 221 222 /* 223 * input routine for IPPRPOTO_MOBILE 224 * This is a little bit diffrent from the other modes, as the 225 * encapsulating header was not prepended, but instead inserted 226 * between IP header and payload 227 */ 228 229 void 230 gre_mobile_input(struct mbuf *m, int hlen) 231 { 232 struct ip *ip; 233 struct mobip_h *mip; 234 struct gre_softc *sc; 235 int msiz; 236 237 if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) { 238 /* No matching tunnel or tunnel is down. */ 239 m_freem(m); 240 return; 241 } 242 243 if (m->m_len < sizeof(*mip)) { 244 m = m_pullup(m, sizeof(*mip)); 245 if (m == NULL) 246 return; 247 } 248 ip = mtod(m, struct ip *); 249 mip = mtod(m, struct mobip_h *); 250 251 GRE2IFP(sc)->if_ipackets++; 252 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 253 254 if (ntohs(mip->mh.proto) & MOB_H_SBIT) { 255 msiz = MOB_H_SIZ_L; 256 mip->mi.ip_src.s_addr = mip->mh.osrc; 257 } else 258 msiz = MOB_H_SIZ_S; 259 260 if (m->m_len < (ip->ip_hl << 2) + msiz) { 261 m = m_pullup(m, (ip->ip_hl << 2) + msiz); 262 if (m == NULL) 263 return; 264 ip = mtod(m, struct ip *); 265 mip = mtod(m, struct mobip_h *); 266 } 267 268 mip->mi.ip_dst.s_addr = mip->mh.odst; 269 mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8); 270 271 if (gre_in_cksum((u_int16_t *)&mip->mh, msiz) != 0) { 272 m_freem(m); 273 return; 274 } 275 276 bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) + 277 (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2)); 278 m->m_len -= msiz; 279 m->m_pkthdr.len -= msiz; 280 281 /* 282 * On FreeBSD, rip_input() supplies us with ip->ip_len 283 * decreased by the lengh of IP header, however, ip_input() 284 * expects it to be full size of IP packet, so adjust accordingly. 285 */ 286 ip->ip_len = htons(ntohs(ip->ip_len) + sizeof(struct ip) - msiz); 287 288 ip->ip_sum = 0; 289 ip->ip_sum = in_cksum(m, (ip->ip_hl << 2)); 290 291 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) { 292 u_int32_t af = AF_INET; 293 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 294 } 295 296 if ((GRE2IFP(sc)->if_flags & IFF_MONITOR) != 0) { 297 m_freem(m); 298 return; 299 } 300 301 m->m_pkthdr.rcvif = GRE2IFP(sc); 302 303 netisr_queue(NETISR_IP, m); 304 } 305 306 /* 307 * Find the gre interface associated with our src/dst/proto set. 308 * 309 * XXXRW: Need some sort of drain/refcount mechanism so that the softc 310 * reference remains valid after it's returned from gre_lookup(). Right 311 * now, I'm thinking it should be reference-counted with a gre_dropref() 312 * when the caller is done with the softc. This is complicated by how 313 * to handle destroying the gre softc; probably using a gre_drain() in 314 * in_gre.c during destroy. 315 */ 316 static struct gre_softc * 317 gre_lookup(struct mbuf *m, u_int8_t proto) 318 { 319 struct ip *ip = mtod(m, struct ip *); 320 struct gre_softc *sc; 321 322 mtx_lock(&gre_mtx); 323 for (sc = LIST_FIRST(&gre_softc_list); sc != NULL; 324 sc = LIST_NEXT(sc, sc_list)) { 325 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) && 326 (sc->g_src.s_addr == ip->ip_dst.s_addr) && 327 (sc->g_proto == proto) && 328 ((GRE2IFP(sc)->if_flags & IFF_UP) != 0)) { 329 mtx_unlock(&gre_mtx); 330 return (sc); 331 } 332 } 333 mtx_unlock(&gre_mtx); 334 335 return (NULL); 336 } 337