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/netisr.h> 61 #include <net/route.h> 62 #include <net/raw_cb.h> 63 64 #ifdef INET 65 #include <netinet/in.h> 66 #include <netinet/in_var.h> 67 #include <netinet/in_systm.h> 68 #include <netinet/ip.h> 69 #include <netinet/ip_var.h> 70 #include <netinet/ip_gre.h> 71 #include <machine/in_cksum.h> 72 #else 73 #error "ip_gre requires INET" 74 #endif 75 76 #ifdef NETATALK 77 #include <netatalk/at.h> 78 #include <netatalk/at_var.h> 79 #include <netatalk/at_extern.h> 80 #endif 81 82 /* Needs IP headers. */ 83 #include <net/if_gre.h> 84 85 #include <machine/stdarg.h> 86 87 #if 1 88 void gre_inet_ntoa(struct in_addr in); /* XXX */ 89 #endif 90 91 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t); 92 93 static struct mbuf *gre_input2(struct mbuf *, int, u_char); 94 95 /* 96 * De-encapsulate a packet and feed it back through ip input (this 97 * routine is called whenever IP gets a packet with proto type 98 * IPPROTO_GRE and a local destination address). 99 * This really is simple 100 */ 101 void 102 gre_input(struct mbuf *m, int off) 103 { 104 int proto; 105 106 proto = (mtod(m, struct ip *))->ip_p; 107 108 m = gre_input2(m, off, proto); 109 110 /* 111 * If no matching tunnel that is up is found. We inject 112 * the mbuf to raw ip socket to see if anyone picks it up. 113 */ 114 if (m != NULL) 115 rip_input(m, off); 116 } 117 118 /* 119 * Decapsulate. Does the real work and is called from gre_input() 120 * (above). Returns an mbuf back if packet is not yet processed, 121 * and NULL if it needs no further processing. proto is the protocol 122 * number of the "calling" foo_input() routine. 123 */ 124 static struct mbuf * 125 gre_input2(struct mbuf *m ,int hlen, u_char proto) 126 { 127 struct greip *gip; 128 int isr; 129 struct gre_softc *sc; 130 u_int16_t flags; 131 u_int32_t af; 132 133 if ((sc = gre_lookup(m, proto)) == NULL) { 134 /* No matching tunnel or tunnel is down. */ 135 return (m); 136 } 137 138 if (m->m_len < sizeof(*gip)) { 139 m = m_pullup(m, sizeof(*gip)); 140 if (m == NULL) 141 return (NULL); 142 } 143 gip = mtod(m, struct greip *); 144 145 GRE2IFP(sc)->if_ipackets++; 146 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 147 148 switch (proto) { 149 case IPPROTO_GRE: 150 hlen += sizeof(struct gre_h); 151 152 /* process GRE flags as packet can be of variable len */ 153 flags = ntohs(gip->gi_flags); 154 155 /* Checksum & Offset are present */ 156 if ((flags & GRE_CP) | (flags & GRE_RP)) 157 hlen += 4; 158 /* We don't support routing fields (variable length) */ 159 if (flags & GRE_RP) 160 return (m); 161 if (flags & GRE_KP) 162 hlen += 4; 163 if (flags & GRE_SP) 164 hlen += 4; 165 166 switch (ntohs(gip->gi_ptype)) { /* ethertypes */ 167 case WCCP_PROTOCOL_TYPE: 168 if (sc->wccp_ver == WCCP_V2) 169 hlen += 4; 170 /* FALLTHROUGH */ 171 case ETHERTYPE_IP: /* shouldn't need a schednetisr(), */ 172 isr = NETISR_IP;/* as we are in ip_input */ 173 af = AF_INET; 174 break; 175 #ifdef INET6 176 case ETHERTYPE_IPV6: 177 isr = NETISR_IPV6; 178 af = AF_INET6; 179 break; 180 #endif 181 #ifdef NETATALK 182 case ETHERTYPE_ATALK: 183 isr = NETISR_ATALK1; 184 af = AF_APPLETALK; 185 break; 186 #endif 187 default: 188 /* Others not yet supported. */ 189 return (m); 190 } 191 break; 192 default: 193 /* Others not yet supported. */ 194 return (m); 195 } 196 197 if (hlen > m->m_pkthdr.len) { 198 m_freem(m); 199 return (NULL); 200 } 201 /* Unlike NetBSD, in FreeBSD m_adj() adjusts m->m_pkthdr.len as well */ 202 m_adj(m, hlen); 203 204 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) { 205 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 206 } 207 208 m->m_pkthdr.rcvif = GRE2IFP(sc); 209 210 netisr_queue(isr, m); 211 212 /* Packet is done, no further processing needed. */ 213 return (NULL); 214 } 215 216 /* 217 * input routine for IPPRPOTO_MOBILE 218 * This is a little bit diffrent from the other modes, as the 219 * encapsulating header was not prepended, but instead inserted 220 * between IP header and payload 221 */ 222 223 void 224 gre_mobile_input(struct mbuf *m, int hlen) 225 { 226 struct ip *ip; 227 struct mobip_h *mip; 228 struct gre_softc *sc; 229 int msiz; 230 231 if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) { 232 /* No matching tunnel or tunnel is down. */ 233 m_freem(m); 234 return; 235 } 236 237 if (m->m_len < sizeof(*mip)) { 238 m = m_pullup(m, sizeof(*mip)); 239 if (m == NULL) 240 return; 241 } 242 ip = mtod(m, struct ip *); 243 mip = mtod(m, struct mobip_h *); 244 245 GRE2IFP(sc)->if_ipackets++; 246 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 247 248 if (ntohs(mip->mh.proto) & MOB_H_SBIT) { 249 msiz = MOB_H_SIZ_L; 250 mip->mi.ip_src.s_addr = mip->mh.osrc; 251 } else 252 msiz = MOB_H_SIZ_S; 253 254 if (m->m_len < (ip->ip_hl << 2) + msiz) { 255 m = m_pullup(m, (ip->ip_hl << 2) + msiz); 256 if (m == NULL) 257 return; 258 ip = mtod(m, struct ip *); 259 mip = mtod(m, struct mobip_h *); 260 } 261 262 mip->mi.ip_dst.s_addr = mip->mh.odst; 263 mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8); 264 265 if (gre_in_cksum((u_int16_t *)&mip->mh, msiz) != 0) { 266 m_freem(m); 267 return; 268 } 269 270 bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) + 271 (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2)); 272 m->m_len -= msiz; 273 m->m_pkthdr.len -= msiz; 274 275 /* 276 * On FreeBSD, rip_input() supplies us with ip->ip_len 277 * decreased by the lengh of IP header, however, ip_input() 278 * expects it to be full size of IP packet, so adjust accordingly. 279 */ 280 ip->ip_len = htons(ntohs(ip->ip_len) + sizeof(struct ip) - msiz); 281 282 ip->ip_sum = 0; 283 ip->ip_sum = in_cksum(m, (ip->ip_hl << 2)); 284 285 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) { 286 u_int32_t af = AF_INET; 287 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 288 } 289 290 m->m_pkthdr.rcvif = GRE2IFP(sc); 291 292 netisr_queue(NETISR_IP, m); 293 } 294 295 /* 296 * Find the gre interface associated with our src/dst/proto set. 297 * 298 * XXXRW: Need some sort of drain/refcount mechanism so that the softc 299 * reference remains valid after it's returned from gre_lookup(). Right 300 * now, I'm thinking it should be reference-counted with a gre_dropref() 301 * when the caller is done with the softc. This is complicated by how 302 * to handle destroying the gre softc; probably using a gre_drain() in 303 * in_gre.c during destroy. 304 */ 305 static struct gre_softc * 306 gre_lookup(struct mbuf *m, u_int8_t proto) 307 { 308 struct ip *ip = mtod(m, struct ip *); 309 struct gre_softc *sc; 310 311 mtx_lock(&gre_mtx); 312 for (sc = LIST_FIRST(&gre_softc_list); sc != NULL; 313 sc = LIST_NEXT(sc, sc_list)) { 314 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) && 315 (sc->g_src.s_addr == ip->ip_dst.s_addr) && 316 (sc->g_proto == proto) && 317 ((GRE2IFP(sc)->if_flags & IFF_UP) != 0)) { 318 mtx_unlock(&gre_mtx); 319 return (sc); 320 } 321 } 322 mtx_unlock(&gre_mtx); 323 324 return (NULL); 325 } 326