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 50 #include <netinet/in.h> 51 #include <netinet/in_systm.h> 52 #include <netinet/ip.h> 53 #include <netinet/ip_var.h> 54 #include <netinet/in_var.h> 55 #include "opt_inet6.h" 56 57 #ifdef INET6 58 #include <netinet/ip6.h> 59 #include <netinet6/ip6_var.h> 60 #endif 61 62 #include "opt_enc.h" 63 #include <netipsec/ipsec.h> 64 #include <netipsec/xform.h> 65 66 #define ENCMTU (1024+512) 67 68 /* XXX this define must have the same value as in OpenBSD */ 69 #define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */ 70 #define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */ 71 #define M_AUTH_AH 0x2000 /* header was authenticated (AH) */ 72 73 struct enchdr { 74 u_int32_t af; 75 u_int32_t spi; 76 u_int32_t flags; 77 }; 78 79 static struct ifnet *encif; 80 static struct mtx enc_mtx; 81 82 struct enc_softc { 83 struct ifnet *sc_ifp; 84 }; 85 86 static int enc_ioctl(struct ifnet *, u_long, caddr_t); 87 static int enc_output(struct ifnet *ifp, struct mbuf *m, 88 struct sockaddr *dst, struct rtentry *rt); 89 static int enc_clone_create(struct if_clone *, int, caddr_t); 90 static void enc_clone_destroy(struct ifnet *); 91 92 IFC_SIMPLE_DECLARE(enc, 1); 93 94 /* 95 * Sysctls. 96 */ 97 98 /* 99 * Before and after are relative to when we are stripping the 100 * outer IP header. 101 */ 102 SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl"); 103 104 SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl"); 105 static int ipsec_filter_mask_in = ENC_BEFORE; 106 SYSCTL_XINT(_net_enc_in, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW, 107 &ipsec_filter_mask_in, 0, "IPsec input firewall filter mask"); 108 static int ipsec_bpf_mask_in = ENC_BEFORE; 109 SYSCTL_XINT(_net_enc_in, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW, 110 &ipsec_bpf_mask_in, 0, "IPsec input bpf mask"); 111 112 SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl"); 113 static int ipsec_filter_mask_out = ENC_BEFORE; 114 SYSCTL_XINT(_net_enc_out, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW, 115 &ipsec_filter_mask_out, 0, "IPsec output firewall filter mask"); 116 static int ipsec_bpf_mask_out = ENC_BEFORE|ENC_AFTER; 117 SYSCTL_XINT(_net_enc_out, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW, 118 &ipsec_bpf_mask_out, 0, "IPsec output bpf mask"); 119 120 static void 121 enc_clone_destroy(struct ifnet *ifp) 122 { 123 KASSERT(ifp != encif, ("%s: destroying encif", __func__)); 124 125 bpfdetach(ifp); 126 if_detach(ifp); 127 if_free(ifp); 128 } 129 130 static int 131 enc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 132 { 133 struct ifnet *ifp; 134 struct enc_softc *sc; 135 136 sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO); 137 ifp = sc->sc_ifp = if_alloc(IFT_ENC); 138 if (ifp == NULL) { 139 free(sc, M_DEVBUF); 140 return (ENOSPC); 141 } 142 143 if_initname(ifp, ifc->ifc_name, unit); 144 ifp->if_mtu = ENCMTU; 145 ifp->if_ioctl = enc_ioctl; 146 ifp->if_output = enc_output; 147 ifp->if_snd.ifq_maxlen = ifqmaxlen; 148 ifp->if_softc = sc; 149 if_attach(ifp); 150 bpfattach(ifp, DLT_ENC, sizeof(struct enchdr)); 151 152 mtx_lock(&enc_mtx); 153 /* grab a pointer to enc0, ignore the rest */ 154 if (encif == NULL) 155 encif = ifp; 156 mtx_unlock(&enc_mtx); 157 158 return (0); 159 } 160 161 static int 162 enc_modevent(module_t mod, int type, void *data) 163 { 164 switch (type) { 165 case MOD_LOAD: 166 mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF); 167 if_clone_attach(&enc_cloner); 168 break; 169 case MOD_UNLOAD: 170 printf("enc module unload - not possible for this module\n"); 171 return (EINVAL); 172 default: 173 return (EOPNOTSUPP); 174 } 175 return (0); 176 } 177 178 static moduledata_t enc_mod = { 179 "enc", 180 enc_modevent, 181 0 182 }; 183 184 DECLARE_MODULE(enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY); 185 186 static int 187 enc_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 188 struct rtentry *rt) 189 { 190 m_freem(m); 191 return (0); 192 } 193 194 /* 195 * Process an ioctl request. 196 */ 197 /* ARGSUSED */ 198 static int 199 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 200 { 201 int error = 0; 202 203 mtx_lock(&enc_mtx); 204 205 switch (cmd) { 206 207 case SIOCSIFFLAGS: 208 if (ifp->if_flags & IFF_UP) 209 ifp->if_drv_flags |= IFF_DRV_RUNNING; 210 else 211 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 212 213 break; 214 215 default: 216 error = EINVAL; 217 } 218 219 mtx_unlock(&enc_mtx); 220 return (error); 221 } 222 223 int 224 ipsec_filter(struct mbuf **mp, int dir, int flags) 225 { 226 int error, i; 227 struct ip *ip; 228 229 KASSERT(encif != NULL, ("%s: encif is null", __func__)); 230 KASSERT(flags & (ENC_IN|ENC_OUT), 231 ("%s: invalid flags: %04x", __func__, flags)); 232 233 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0) 234 return (0); 235 236 if (flags & ENC_IN) { 237 if ((flags & ipsec_filter_mask_in) == 0) 238 return (0); 239 } else { 240 if ((flags & ipsec_filter_mask_out) == 0) 241 return (0); 242 } 243 244 /* Skip pfil(9) if no filters are loaded */ 245 if (!(PFIL_HOOKED(&inet_pfil_hook) 246 #ifdef INET6 247 || PFIL_HOOKED(&inet6_pfil_hook) 248 #endif 249 )) { 250 return (0); 251 } 252 253 i = min((*mp)->m_pkthdr.len, max_protohdr); 254 if ((*mp)->m_len < i) { 255 *mp = m_pullup(*mp, i); 256 if (*mp == NULL) { 257 printf("%s: m_pullup failed\n", __func__); 258 return (-1); 259 } 260 } 261 262 error = 0; 263 ip = mtod(*mp, struct ip *); 264 switch (ip->ip_v) { 265 case 4: 266 /* 267 * before calling the firewall, swap fields the same as 268 * IP does. here we assume the header is contiguous 269 */ 270 ip->ip_len = ntohs(ip->ip_len); 271 ip->ip_off = ntohs(ip->ip_off); 272 273 error = pfil_run_hooks(&inet_pfil_hook, mp, 274 encif, dir, NULL); 275 276 if (*mp == NULL || error != 0) 277 break; 278 279 /* restore byte ordering */ 280 ip = mtod(*mp, struct ip *); 281 ip->ip_len = htons(ip->ip_len); 282 ip->ip_off = htons(ip->ip_off); 283 break; 284 285 #ifdef INET6 286 case 6: 287 error = pfil_run_hooks(&inet6_pfil_hook, mp, 288 encif, dir, NULL); 289 break; 290 #endif 291 default: 292 printf("%s: unknown IP version\n", __func__); 293 } 294 295 /* 296 * If the mbuf was consumed by the filter for requeueing (dummynet, etc) 297 * then error will be zero but we still want to return an error to our 298 * caller so the null mbuf isn't forwarded further. 299 */ 300 if (*mp == NULL && error == 0) 301 return (-1); /* Consumed by the filter */ 302 if (*mp == NULL) 303 return (error); 304 if (error != 0) 305 goto bad; 306 307 return (error); 308 309 bad: 310 m_freem(*mp); 311 *mp = NULL; 312 return (error); 313 } 314 315 void 316 ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af, int flags) 317 { 318 int mflags; 319 struct enchdr hdr; 320 321 KASSERT(encif != NULL, ("%s: encif is null", __func__)); 322 KASSERT(flags & (ENC_IN|ENC_OUT), 323 ("%s: invalid flags: %04x", __func__, flags)); 324 325 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0) 326 return; 327 328 if (flags & ENC_IN) { 329 if ((flags & ipsec_bpf_mask_in) == 0) 330 return; 331 } else { 332 if ((flags & ipsec_bpf_mask_out) == 0) 333 return; 334 } 335 336 if (bpf_peers_present(encif->if_bpf)) { 337 mflags = 0; 338 hdr.spi = 0; 339 if (!sav) { 340 struct m_tag *mtag; 341 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 342 if (mtag != NULL) { 343 struct tdb_ident *tdbi; 344 tdbi = (struct tdb_ident *) (mtag + 1); 345 if (tdbi->alg_enc != SADB_EALG_NONE) 346 mflags |= M_CONF; 347 if (tdbi->alg_auth != SADB_AALG_NONE) 348 mflags |= M_AUTH; 349 hdr.spi = tdbi->spi; 350 } 351 } else { 352 if (sav->alg_enc != SADB_EALG_NONE) 353 mflags |= M_CONF; 354 if (sav->alg_auth != SADB_AALG_NONE) 355 mflags |= M_AUTH; 356 hdr.spi = sav->spi; 357 } 358 359 /* 360 * We need to prepend the address family as a four byte 361 * field. Cons up a dummy header to pacify bpf. This 362 * is safe because bpf will only read from the mbuf 363 * (i.e., it won't try to free it or keep a pointer a 364 * to it). 365 */ 366 hdr.af = af; 367 /* hdr.spi already set above */ 368 hdr.flags = mflags; 369 370 bpf_mtap2(encif->if_bpf, &hdr, sizeof(hdr), m); 371 } 372 } 373