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 int 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 #if __STDC__ 108 gre_input(struct mbuf *m, ...) 109 #else 110 gre_input(m, va_alist) 111 struct mbuf *m; 112 va_dcl 113 #endif 114 { 115 int off, ret, proto; 116 va_list ap; 117 118 va_start(ap, m); 119 off = va_arg(ap, int); 120 va_end(ap); 121 proto = (mtod(m, struct ip *))->ip_p; 122 123 ret = gre_input2(m, off, proto); 124 /* 125 * ret == 0 : packet not processed, meaning that 126 * no matching tunnel that is up is found. 127 * we inject it to raw ip socket to see if anyone picks it up. 128 */ 129 if (ret == 0) 130 rip_input(m, off); 131 } 132 133 /* 134 * decapsulate. 135 * Does the real work and is called from gre_input() (above) 136 * returns 0 if packet is not yet processed 137 * and 1 if it needs no further processing 138 * proto is the protocol number of the "calling" foo_input() 139 * routine. 140 */ 141 static int 142 gre_input2(struct mbuf *m ,int hlen, u_char proto) 143 { 144 struct greip *gip; 145 int isr; 146 struct gre_softc *sc; 147 u_int16_t flags; 148 u_int32_t af; 149 150 if ((sc = gre_lookup(m, proto)) == NULL) { 151 /* No matching tunnel or tunnel is down. */ 152 return (0); 153 } 154 155 if (m->m_len < sizeof(*gip)) { 156 m = m_pullup(m, sizeof(*gip)); 157 if (m == NULL) 158 return (ENOBUFS); 159 } 160 gip = mtod(m, struct greip *); 161 162 GRE2IFP(sc)->if_ipackets++; 163 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 164 165 switch (proto) { 166 case IPPROTO_GRE: 167 hlen += sizeof(struct gre_h); 168 169 /* process GRE flags as packet can be of variable len */ 170 flags = ntohs(gip->gi_flags); 171 172 /* Checksum & Offset are present */ 173 if ((flags & GRE_CP) | (flags & GRE_RP)) 174 hlen += 4; 175 /* We don't support routing fields (variable length) */ 176 if (flags & GRE_RP) 177 return (0); 178 if (flags & GRE_KP) 179 hlen += 4; 180 if (flags & GRE_SP) 181 hlen += 4; 182 183 switch (ntohs(gip->gi_ptype)) { /* ethertypes */ 184 case WCCP_PROTOCOL_TYPE: 185 if (sc->wccp_ver == WCCP_V2) 186 hlen += 4; 187 /* FALLTHROUGH */ 188 case ETHERTYPE_IP: /* shouldn't need a schednetisr(), */ 189 isr = NETISR_IP;/* as we are in ip_input */ 190 af = AF_INET; 191 break; 192 #ifdef INET6 193 case ETHERTYPE_IPV6: 194 isr = NETISR_IPV6; 195 af = AF_INET6; 196 break; 197 #endif 198 #ifdef NETATALK 199 case ETHERTYPE_ATALK: 200 isr = NETISR_ATALK1; 201 af = AF_APPLETALK; 202 break; 203 #endif 204 default: /* others not yet supported */ 205 return (0); 206 } 207 break; 208 default: 209 /* others not yet supported */ 210 return (0); 211 } 212 213 if (hlen > m->m_pkthdr.len) { 214 m_freem(m); 215 return (EINVAL); 216 } 217 /* Unlike NetBSD, in FreeBSD m_adj() adjusts m->m_pkthdr.len as well */ 218 m_adj(m, hlen); 219 220 if (GRE2IFP(sc)->if_bpf) { 221 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 222 } 223 224 m->m_pkthdr.rcvif = GRE2IFP(sc); 225 226 netisr_dispatch(isr, m); 227 228 return (1); /* packet is done, no further processing needed */ 229 } 230 231 /* 232 * input routine for IPPRPOTO_MOBILE 233 * This is a little bit diffrent from the other modes, as the 234 * encapsulating header was not prepended, but instead inserted 235 * between IP header and payload 236 */ 237 238 void 239 #if __STDC__ 240 gre_mobile_input(struct mbuf *m, ...) 241 #else 242 gre_mobile_input(m, va_alist) 243 struct mbuf *m; 244 va_dcl 245 #endif 246 { 247 struct ip *ip; 248 struct mobip_h *mip; 249 struct gre_softc *sc; 250 int hlen; 251 va_list ap; 252 int msiz; 253 254 va_start(ap, m); 255 hlen = va_arg(ap, int); 256 va_end(ap); 257 258 if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) { 259 /* No matching tunnel or tunnel is down. */ 260 m_freem(m); 261 return; 262 } 263 264 if (m->m_len < sizeof(*mip)) { 265 m = m_pullup(m, sizeof(*mip)); 266 if (m == NULL) 267 return; 268 } 269 ip = mtod(m, struct ip *); 270 mip = mtod(m, struct mobip_h *); 271 272 GRE2IFP(sc)->if_ipackets++; 273 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len; 274 275 if (ntohs(mip->mh.proto) & MOB_H_SBIT) { 276 msiz = MOB_H_SIZ_L; 277 mip->mi.ip_src.s_addr = mip->mh.osrc; 278 } else 279 msiz = MOB_H_SIZ_S; 280 281 if (m->m_len < (ip->ip_hl << 2) + msiz) { 282 m = m_pullup(m, (ip->ip_hl << 2) + msiz); 283 if (m == NULL) 284 return; 285 ip = mtod(m, struct ip *); 286 mip = mtod(m, struct mobip_h *); 287 } 288 289 mip->mi.ip_dst.s_addr = mip->mh.odst; 290 mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8); 291 292 if (gre_in_cksum((u_int16_t *)&mip->mh, msiz) != 0) { 293 m_freem(m); 294 return; 295 } 296 297 bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) + 298 (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2)); 299 m->m_len -= msiz; 300 m->m_pkthdr.len -= msiz; 301 302 /* 303 * On FreeBSD, rip_input() supplies us with ip->ip_len 304 * already converted into host byteorder and also decreases 305 * it by the lengh of IP header, however, ip_input() expects 306 * that this field is in the original format (network byteorder 307 * and full size of IP packet), so that adjust accordingly. 308 */ 309 ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz); 310 311 ip->ip_sum = 0; 312 ip->ip_sum = in_cksum(m, (ip->ip_hl << 2)); 313 314 if (GRE2IFP(sc)->if_bpf) { 315 u_int32_t af = AF_INET; 316 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m); 317 } 318 319 m->m_pkthdr.rcvif = GRE2IFP(sc); 320 321 netisr_dispatch(NETISR_IP, m); 322 } 323 324 /* 325 * Find the gre interface associated with our src/dst/proto set. 326 * 327 * XXXRW: Need some sort of drain/refcount mechanism so that the softc 328 * reference remains valid after it's returned from gre_lookup(). Right 329 * now, I'm thinking it should be reference-counted with a gre_dropref() 330 * when the caller is done with the softc. This is complicated by how 331 * to handle destroying the gre softc; probably using a gre_drain() in 332 * in_gre.c during destroy. 333 */ 334 static struct gre_softc * 335 gre_lookup(m, proto) 336 struct mbuf *m; 337 u_int8_t proto; 338 { 339 struct ip *ip = mtod(m, struct ip *); 340 struct gre_softc *sc; 341 342 mtx_lock(&gre_mtx); 343 for (sc = LIST_FIRST(&gre_softc_list); sc != NULL; 344 sc = LIST_NEXT(sc, sc_list)) { 345 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) && 346 (sc->g_src.s_addr == ip->ip_dst.s_addr) && 347 (sc->g_proto == proto) && 348 ((GRE2IFP(sc)->if_flags & IFF_UP) != 0)) { 349 mtx_unlock(&gre_mtx); 350 return (sc); 351 } 352 } 353 mtx_unlock(&gre_mtx); 354 355 return (NULL); 356 } 357