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 <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/malloc.h> 34 #include <sys/mbuf.h> 35 #include <sys/module.h> 36 #include <machine/bus.h> 37 #include <sys/rman.h> 38 #include <sys/socket.h> 39 #include <sys/sockio.h> 40 #include <sys/sysctl.h> 41 42 #include <net/if.h> 43 #include <net/if_clone.h> 44 #include <net/if_types.h> 45 #include <net/pfil.h> 46 #include <net/route.h> 47 #include <net/netisr.h> 48 #include <net/bpf.h> 49 #include <net/vnet.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_systm.h> 53 #include <netinet/ip.h> 54 #include <netinet/ip_var.h> 55 #include <netinet/in_var.h> 56 #include "opt_inet6.h" 57 58 #ifdef INET6 59 #include <netinet/ip6.h> 60 #include <netinet6/ip6_var.h> 61 #endif 62 63 #include "opt_enc.h" 64 #include <netipsec/ipsec.h> 65 #include <netipsec/xform.h> 66 67 #define ENCMTU (1024+512) 68 69 /* XXX this define must have the same value as in OpenBSD */ 70 #define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */ 71 #define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */ 72 #define M_AUTH_AH 0x2000 /* header was authenticated (AH) */ 73 74 struct enchdr { 75 u_int32_t af; 76 u_int32_t spi; 77 u_int32_t flags; 78 }; 79 80 struct ifnet *encif; 81 static struct mtx enc_mtx; 82 83 struct enc_softc { 84 struct ifnet *sc_ifp; 85 }; 86 87 static int enc_ioctl(struct ifnet *, u_long, caddr_t); 88 static int enc_output(struct ifnet *ifp, struct mbuf *m, 89 struct sockaddr *dst, struct route *ro); 90 static int enc_clone_create(struct if_clone *, int, caddr_t); 91 static void enc_clone_destroy(struct ifnet *); 92 93 IFC_SIMPLE_DECLARE(enc, 1); 94 95 /* 96 * Sysctls. 97 */ 98 99 /* 100 * Before and after are relative to when we are stripping the 101 * outer IP header. 102 */ 103 SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl"); 104 105 SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl"); 106 static int ipsec_filter_mask_in = ENC_BEFORE; 107 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW, 108 &ipsec_filter_mask_in, 0, "IPsec input firewall filter mask"); 109 static int ipsec_bpf_mask_in = ENC_BEFORE; 110 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW, 111 &ipsec_bpf_mask_in, 0, "IPsec input bpf mask"); 112 113 SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl"); 114 static int ipsec_filter_mask_out = ENC_BEFORE; 115 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW, 116 &ipsec_filter_mask_out, 0, "IPsec output firewall filter mask"); 117 static int ipsec_bpf_mask_out = ENC_BEFORE|ENC_AFTER; 118 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW, 119 &ipsec_bpf_mask_out, 0, "IPsec output bpf mask"); 120 121 static void 122 enc_clone_destroy(struct ifnet *ifp) 123 { 124 KASSERT(ifp != encif, ("%s: destroying encif", __func__)); 125 126 bpfdetach(ifp); 127 if_detach(ifp); 128 if_free(ifp); 129 } 130 131 static int 132 enc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 133 { 134 struct ifnet *ifp; 135 struct enc_softc *sc; 136 137 sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO); 138 ifp = sc->sc_ifp = if_alloc(IFT_ENC); 139 if (ifp == NULL) { 140 free(sc, M_DEVBUF); 141 return (ENOSPC); 142 } 143 144 if_initname(ifp, ifc->ifc_name, unit); 145 ifp->if_mtu = ENCMTU; 146 ifp->if_ioctl = enc_ioctl; 147 ifp->if_output = enc_output; 148 ifp->if_snd.ifq_maxlen = ifqmaxlen; 149 ifp->if_softc = sc; 150 if_attach(ifp); 151 bpfattach(ifp, DLT_ENC, sizeof(struct enchdr)); 152 153 mtx_lock(&enc_mtx); 154 /* grab a pointer to enc0, ignore the rest */ 155 if (encif == NULL) 156 encif = ifp; 157 mtx_unlock(&enc_mtx); 158 159 return (0); 160 } 161 162 static int 163 enc_modevent(module_t mod, int type, void *data) 164 { 165 switch (type) { 166 case MOD_LOAD: 167 mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF); 168 if_clone_attach(&enc_cloner); 169 break; 170 case MOD_UNLOAD: 171 printf("enc module unload - not possible for this module\n"); 172 return (EINVAL); 173 default: 174 return (EOPNOTSUPP); 175 } 176 return (0); 177 } 178 179 static moduledata_t enc_mod = { 180 "enc", 181 enc_modevent, 182 0 183 }; 184 185 DECLARE_MODULE(enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY); 186 187 static int 188 enc_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 189 struct route *ro) 190 { 191 m_freem(m); 192 return (0); 193 } 194 195 /* 196 * Process an ioctl request. 197 */ 198 /* ARGSUSED */ 199 static int 200 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 201 { 202 int error = 0; 203 204 mtx_lock(&enc_mtx); 205 206 switch (cmd) { 207 208 case SIOCSIFFLAGS: 209 if (ifp->if_flags & IFF_UP) 210 ifp->if_drv_flags |= IFF_DRV_RUNNING; 211 else 212 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 213 214 break; 215 216 default: 217 error = EINVAL; 218 } 219 220 mtx_unlock(&enc_mtx); 221 return (error); 222 } 223 224 int 225 ipsec_filter(struct mbuf **mp, int dir, int flags) 226 { 227 int error, i; 228 struct ip *ip; 229 230 KASSERT(encif != NULL, ("%s: encif is null", __func__)); 231 KASSERT(flags & (ENC_IN|ENC_OUT), 232 ("%s: invalid flags: %04x", __func__, flags)); 233 234 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0) 235 return (0); 236 237 if (flags & ENC_IN) { 238 if ((flags & ipsec_filter_mask_in) == 0) 239 return (0); 240 } else { 241 if ((flags & ipsec_filter_mask_out) == 0) 242 return (0); 243 } 244 245 /* Skip pfil(9) if no filters are loaded */ 246 if (!(PFIL_HOOKED(&V_inet_pfil_hook) 247 #ifdef INET6 248 || PFIL_HOOKED(&V_inet6_pfil_hook) 249 #endif 250 )) { 251 return (0); 252 } 253 254 i = min((*mp)->m_pkthdr.len, max_protohdr); 255 if ((*mp)->m_len < i) { 256 *mp = m_pullup(*mp, i); 257 if (*mp == NULL) { 258 printf("%s: m_pullup failed\n", __func__); 259 return (-1); 260 } 261 } 262 263 error = 0; 264 ip = mtod(*mp, struct ip *); 265 switch (ip->ip_v) { 266 case 4: 267 /* 268 * before calling the firewall, swap fields the same as 269 * IP does. here we assume the header is contiguous 270 */ 271 ip->ip_len = ntohs(ip->ip_len); 272 ip->ip_off = ntohs(ip->ip_off); 273 274 error = pfil_run_hooks(&V_inet_pfil_hook, mp, 275 encif, dir, NULL); 276 277 if (*mp == NULL || error != 0) 278 break; 279 280 /* restore byte ordering */ 281 ip = mtod(*mp, struct ip *); 282 ip->ip_len = htons(ip->ip_len); 283 ip->ip_off = htons(ip->ip_off); 284 break; 285 286 #ifdef INET6 287 case 6: 288 error = pfil_run_hooks(&V_inet6_pfil_hook, mp, 289 encif, dir, NULL); 290 break; 291 #endif 292 default: 293 printf("%s: unknown IP version\n", __func__); 294 } 295 296 /* 297 * If the mbuf was consumed by the filter for requeueing (dummynet, etc) 298 * then error will be zero but we still want to return an error to our 299 * caller so the null mbuf isn't forwarded further. 300 */ 301 if (*mp == NULL && error == 0) 302 return (-1); /* Consumed by the filter */ 303 if (*mp == NULL) 304 return (error); 305 if (error != 0) 306 goto bad; 307 308 return (error); 309 310 bad: 311 m_freem(*mp); 312 *mp = NULL; 313 return (error); 314 } 315 316 void 317 ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af, int flags) 318 { 319 int mflags; 320 struct enchdr hdr; 321 322 KASSERT(encif != NULL, ("%s: encif is null", __func__)); 323 KASSERT(flags & (ENC_IN|ENC_OUT), 324 ("%s: invalid flags: %04x", __func__, flags)); 325 326 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0) 327 return; 328 329 if (flags & ENC_IN) { 330 if ((flags & ipsec_bpf_mask_in) == 0) 331 return; 332 } else { 333 if ((flags & ipsec_bpf_mask_out) == 0) 334 return; 335 } 336 337 if (bpf_peers_present(encif->if_bpf)) { 338 mflags = 0; 339 hdr.spi = 0; 340 if (!sav) { 341 struct m_tag *mtag; 342 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 343 if (mtag != NULL) { 344 struct tdb_ident *tdbi; 345 tdbi = (struct tdb_ident *) (mtag + 1); 346 if (tdbi->alg_enc != SADB_EALG_NONE) 347 mflags |= M_CONF; 348 if (tdbi->alg_auth != SADB_AALG_NONE) 349 mflags |= M_AUTH; 350 hdr.spi = tdbi->spi; 351 } 352 } else { 353 if (sav->alg_enc != SADB_EALG_NONE) 354 mflags |= M_CONF; 355 if (sav->alg_auth != SADB_AALG_NONE) 356 mflags |= M_AUTH; 357 hdr.spi = sav->spi; 358 } 359 360 /* 361 * We need to prepend the address family as a four byte 362 * field. Cons up a dummy header to pacify bpf. This 363 * is safe because bpf will only read from the mbuf 364 * (i.e., it won't try to free it or keep a pointer a 365 * to it). 366 */ 367 hdr.af = af; 368 /* hdr.spi already set above */ 369 hdr.flags = mflags; 370 371 bpf_mtap2(encif->if_bpf, &hdr, sizeof(hdr), m); 372 } 373 } 374