1 /*- 2 * Copyright (c) 2006 The FreeBSD Project. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #include "opt_inet.h" 31 #include "opt_inet6.h" 32 #include "opt_enc.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/malloc.h> 38 #include <sys/mbuf.h> 39 #include <sys/module.h> 40 #include <machine/bus.h> 41 #include <sys/rman.h> 42 #include <sys/socket.h> 43 #include <sys/sockio.h> 44 #include <sys/sysctl.h> 45 46 #include <net/if.h> 47 #include <net/if_clone.h> 48 #include <net/if_types.h> 49 #include <net/pfil.h> 50 #include <net/route.h> 51 #include <net/netisr.h> 52 #include <net/bpf.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_var.h> 59 #include <netinet/in_var.h> 60 61 #ifdef INET6 62 #include <netinet/ip6.h> 63 #include <netinet6/ip6_var.h> 64 #endif 65 66 #include <netipsec/ipsec.h> 67 #include <netipsec/xform.h> 68 69 #define ENCMTU (1024+512) 70 71 /* XXX this define must have the same value as in OpenBSD */ 72 #define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */ 73 #define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */ 74 #define M_AUTH_AH 0x2000 /* header was authenticated (AH) */ 75 76 struct enchdr { 77 u_int32_t af; 78 u_int32_t spi; 79 u_int32_t flags; 80 }; 81 82 struct ifnet *encif; 83 static struct mtx enc_mtx; 84 85 struct enc_softc { 86 struct ifnet *sc_ifp; 87 }; 88 89 static int enc_ioctl(struct ifnet *, u_long, caddr_t); 90 static int enc_output(struct ifnet *ifp, struct mbuf *m, 91 struct sockaddr *dst, struct route *ro); 92 static int enc_clone_create(struct if_clone *, int, caddr_t); 93 static void enc_clone_destroy(struct ifnet *); 94 95 IFC_SIMPLE_DECLARE(enc, 1); 96 97 /* 98 * Sysctls. 99 */ 100 101 /* 102 * Before and after are relative to when we are stripping the 103 * outer IP header. 104 */ 105 static SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl"); 106 107 static SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl"); 108 static int ipsec_filter_mask_in = ENC_BEFORE; 109 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW, 110 &ipsec_filter_mask_in, 0, "IPsec input firewall filter mask"); 111 static int ipsec_bpf_mask_in = ENC_BEFORE; 112 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW, 113 &ipsec_bpf_mask_in, 0, "IPsec input bpf mask"); 114 115 static SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl"); 116 static int ipsec_filter_mask_out = ENC_BEFORE; 117 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW, 118 &ipsec_filter_mask_out, 0, "IPsec output firewall filter mask"); 119 static int ipsec_bpf_mask_out = ENC_BEFORE|ENC_AFTER; 120 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW, 121 &ipsec_bpf_mask_out, 0, "IPsec output bpf mask"); 122 123 static void 124 enc_clone_destroy(struct ifnet *ifp) 125 { 126 KASSERT(ifp != encif, ("%s: destroying encif", __func__)); 127 128 bpfdetach(ifp); 129 if_detach(ifp); 130 if_free(ifp); 131 } 132 133 static int 134 enc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 135 { 136 struct ifnet *ifp; 137 struct enc_softc *sc; 138 139 sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO); 140 ifp = sc->sc_ifp = if_alloc(IFT_ENC); 141 if (ifp == NULL) { 142 free(sc, M_DEVBUF); 143 return (ENOSPC); 144 } 145 146 if_initname(ifp, ifc->ifc_name, unit); 147 ifp->if_mtu = ENCMTU; 148 ifp->if_ioctl = enc_ioctl; 149 ifp->if_output = enc_output; 150 ifp->if_snd.ifq_maxlen = ifqmaxlen; 151 ifp->if_softc = sc; 152 if_attach(ifp); 153 bpfattach(ifp, DLT_ENC, sizeof(struct enchdr)); 154 155 mtx_lock(&enc_mtx); 156 /* grab a pointer to enc0, ignore the rest */ 157 if (encif == NULL) 158 encif = ifp; 159 mtx_unlock(&enc_mtx); 160 161 return (0); 162 } 163 164 static int 165 enc_modevent(module_t mod, int type, void *data) 166 { 167 switch (type) { 168 case MOD_LOAD: 169 mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF); 170 if_clone_attach(&enc_cloner); 171 break; 172 case MOD_UNLOAD: 173 printf("enc module unload - not possible for this module\n"); 174 return (EINVAL); 175 default: 176 return (EOPNOTSUPP); 177 } 178 return (0); 179 } 180 181 static moduledata_t enc_mod = { 182 "enc", 183 enc_modevent, 184 0 185 }; 186 187 DECLARE_MODULE(enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY); 188 189 static int 190 enc_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 191 struct route *ro) 192 { 193 m_freem(m); 194 return (0); 195 } 196 197 /* 198 * Process an ioctl request. 199 */ 200 /* ARGSUSED */ 201 static int 202 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 203 { 204 int error = 0; 205 206 mtx_lock(&enc_mtx); 207 208 switch (cmd) { 209 210 case SIOCSIFFLAGS: 211 if (ifp->if_flags & IFF_UP) 212 ifp->if_drv_flags |= IFF_DRV_RUNNING; 213 else 214 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 215 216 break; 217 218 default: 219 error = EINVAL; 220 } 221 222 mtx_unlock(&enc_mtx); 223 return (error); 224 } 225 226 int 227 ipsec_filter(struct mbuf **mp, int dir, int flags) 228 { 229 int error, i; 230 struct ip *ip; 231 232 KASSERT(encif != NULL, ("%s: encif is null", __func__)); 233 KASSERT(flags & (ENC_IN|ENC_OUT), 234 ("%s: invalid flags: %04x", __func__, flags)); 235 236 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0) 237 return (0); 238 239 if (flags & ENC_IN) { 240 if ((flags & ipsec_filter_mask_in) == 0) 241 return (0); 242 } else { 243 if ((flags & ipsec_filter_mask_out) == 0) 244 return (0); 245 } 246 247 /* Skip pfil(9) if no filters are loaded */ 248 if (1 249 #ifdef INET 250 && !PFIL_HOOKED(&V_inet_pfil_hook) 251 #endif 252 #ifdef INET6 253 && !PFIL_HOOKED(&V_inet6_pfil_hook) 254 #endif 255 ) { 256 return (0); 257 } 258 259 i = min((*mp)->m_pkthdr.len, max_protohdr); 260 if ((*mp)->m_len < i) { 261 *mp = m_pullup(*mp, i); 262 if (*mp == NULL) { 263 printf("%s: m_pullup failed\n", __func__); 264 return (-1); 265 } 266 } 267 268 error = 0; 269 ip = mtod(*mp, struct ip *); 270 switch (ip->ip_v) { 271 #ifdef INET 272 case 4: 273 /* 274 * before calling the firewall, swap fields the same as 275 * IP does. here we assume the header is contiguous 276 */ 277 ip->ip_len = ntohs(ip->ip_len); 278 ip->ip_off = ntohs(ip->ip_off); 279 280 error = pfil_run_hooks(&V_inet_pfil_hook, mp, 281 encif, dir, NULL); 282 283 if (*mp == NULL || error != 0) 284 break; 285 286 /* restore byte ordering */ 287 ip = mtod(*mp, struct ip *); 288 ip->ip_len = htons(ip->ip_len); 289 ip->ip_off = htons(ip->ip_off); 290 break; 291 #endif 292 #ifdef INET6 293 case 6: 294 error = pfil_run_hooks(&V_inet6_pfil_hook, mp, 295 encif, dir, NULL); 296 break; 297 #endif 298 default: 299 printf("%s: unknown IP version\n", __func__); 300 } 301 302 /* 303 * If the mbuf was consumed by the filter for requeueing (dummynet, etc) 304 * then error will be zero but we still want to return an error to our 305 * caller so the null mbuf isn't forwarded further. 306 */ 307 if (*mp == NULL && error == 0) 308 return (-1); /* Consumed by the filter */ 309 if (*mp == NULL) 310 return (error); 311 if (error != 0) 312 goto bad; 313 314 return (error); 315 316 bad: 317 m_freem(*mp); 318 *mp = NULL; 319 return (error); 320 } 321 322 void 323 ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af, int flags) 324 { 325 int mflags; 326 struct enchdr hdr; 327 328 KASSERT(encif != NULL, ("%s: encif is null", __func__)); 329 KASSERT(flags & (ENC_IN|ENC_OUT), 330 ("%s: invalid flags: %04x", __func__, flags)); 331 332 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0) 333 return; 334 335 if (flags & ENC_IN) { 336 if ((flags & ipsec_bpf_mask_in) == 0) 337 return; 338 } else { 339 if ((flags & ipsec_bpf_mask_out) == 0) 340 return; 341 } 342 343 if (bpf_peers_present(encif->if_bpf)) { 344 mflags = 0; 345 hdr.spi = 0; 346 if (!sav) { 347 struct m_tag *mtag; 348 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 349 if (mtag != NULL) { 350 struct tdb_ident *tdbi; 351 tdbi = (struct tdb_ident *) (mtag + 1); 352 if (tdbi->alg_enc != SADB_EALG_NONE) 353 mflags |= M_CONF; 354 if (tdbi->alg_auth != SADB_AALG_NONE) 355 mflags |= M_AUTH; 356 hdr.spi = tdbi->spi; 357 } 358 } else { 359 if (sav->alg_enc != SADB_EALG_NONE) 360 mflags |= M_CONF; 361 if (sav->alg_auth != SADB_AALG_NONE) 362 mflags |= M_AUTH; 363 hdr.spi = sav->spi; 364 } 365 366 /* 367 * We need to prepend the address family as a four byte 368 * field. Cons up a dummy header to pacify bpf. This 369 * is safe because bpf will only read from the mbuf 370 * (i.e., it won't try to free it or keep a pointer a 371 * to it). 372 */ 373 hdr.af = af; 374 /* hdr.spi already set above */ 375 hdr.flags = mflags; 376 377 bpf_mtap2(encif->if_bpf, &hdr, sizeof(hdr), m); 378 } 379 } 380