sys/net/if_enc.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause
   3  *
   4  * Copyright (c) 2006 The FreeBSD Project.
   5  * Copyright (c) 2015 Andrey V. Elsukov <ae@FreeBSD.org>
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include "opt_inet.h"
  32 #include "opt_inet6.h"
  33 #include "opt_ipsec.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/hhook.h>
  38 #include <sys/kernel.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mbuf.h>
  41 #include <sys/module.h>
  42 #include <machine/bus.h>
  43 #include <sys/rman.h>
  44 #include <sys/socket.h>
  45 #include <sys/sockio.h>
  46 #include <sys/sysctl.h>
  47
  48 #include <net/if.h>
  49 #include <net/if_enc.h>
  50 #include <net/if_var.h>
  51 #include <net/if_private.h>
  52 #include <net/if_clone.h>
  53 #include <net/if_types.h>
  54 #include <net/pfil.h>
  55 #include <net/route.h>
  56 #include <net/netisr.h>
  57 #include <net/bpf.h>
  58 #include <net/vnet.h>
  59
  60 #include <netinet/in.h>
  61 #include <netinet/in_systm.h>
  62 #include <netinet/ip.h>
  63 #include <netinet/ip_var.h>
  64 #include <netinet/in_var.h>
  65
  66 #ifdef INET6
  67 #include <netinet/ip6.h>
  68 #include <netinet6/ip6_var.h>
  69 #endif
  70
  71 #include <netipsec/ipsec.h>
  72 #include <netipsec/xform.h>
  73
  74 #define ENCMTU          (1024+512)
  75
  76 /* XXX this define must have the same value as in OpenBSD */
  77 #define M_CONF          0x0400  /* payload was encrypted (ESP-transport) */
  78 #define M_AUTH          0x0800  /* payload was authenticated (AH or ESP auth) */
  79 #define M_AUTH_AH       0x2000  /* header was authenticated (AH) */
  80
  81 struct enchdr {
  82         u_int32_t af;
  83         u_int32_t spi;
  84         u_int32_t flags;
  85 };
  86 struct enc_softc {
  87         struct  ifnet *sc_ifp;
  88 };
  89 VNET_DEFINE_STATIC(struct enc_softc *, enc_sc);
  90 #define V_enc_sc        VNET(enc_sc)
  91 VNET_DEFINE_STATIC(struct if_clone *, enc_cloner);
  92 #define V_enc_cloner    VNET(enc_cloner)
  93
  94 static int      enc_ioctl(struct ifnet *, u_long, caddr_t);
  95 static int      enc_output(struct ifnet *, struct mbuf *,
  96     const struct sockaddr *, struct route *);
  97 static int      enc_clone_create(struct if_clone *, char *, size_t,
  98     struct ifc_data *, struct ifnet **);
  99 static int      enc_clone_destroy(struct if_clone *, struct ifnet *, uint32_t);
 100 static void     enc_add_hhooks(struct enc_softc *);
 101 static void     enc_remove_hhooks(struct enc_softc *);
 102
 103 static const char encname[] = "enc";
 104
 105 #define IPSEC_ENC_AFTER_PFIL    0x04
 106 /*
 107  * Before and after are relative to when we are stripping the
 108  * outer IP header.
 109  *
 110  * AFTER_PFIL flag used only for bpf_mask_*. It enables BPF capturing
 111  * after PFIL hook execution. It might be useful when PFIL hook does
 112  * some changes to the packet, e.g. address translation. If PFIL hook
 113  * consumes mbuf, nothing will be captured.
 114  */
 115 VNET_DEFINE_STATIC(int, filter_mask_in) = IPSEC_ENC_BEFORE;
 116 VNET_DEFINE_STATIC(int, bpf_mask_in) = IPSEC_ENC_BEFORE;
 117 VNET_DEFINE_STATIC(int, filter_mask_out) = IPSEC_ENC_BEFORE;
 118 VNET_DEFINE_STATIC(int, bpf_mask_out) = IPSEC_ENC_BEFORE | IPSEC_ENC_AFTER;
 119 #define V_filter_mask_in        VNET(filter_mask_in)
 120 #define V_bpf_mask_in           VNET(bpf_mask_in)
 121 #define V_filter_mask_out       VNET(filter_mask_out)
 122 #define V_bpf_mask_out          VNET(bpf_mask_out)
 123
 124 static SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 125     "enc sysctl");
 126 static SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 127     "enc input sysctl");
 128 static SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 129     "enc output sysctl");
 130 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask,
 131     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_in), 0,
 132     "IPsec input firewall filter mask");
 133 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask,
 134     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_in), 0,
 135     "IPsec input bpf mask");
 136 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask,
 137     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_out), 0,
 138     "IPsec output firewall filter mask");
 139 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask,
 140     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_out), 0,
 141     "IPsec output bpf mask");
 142
 143 static int
 144 enc_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
 145 {
 146         struct enc_softc *sc;
 147
 148         if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
 149                 return (EINVAL);
 150
 151         sc = ifp->if_softc;
 152         KASSERT(sc == V_enc_sc, ("sc != ifp->if_softc"));
 153
 154         bpfdetach(ifp);
 155         if_detach(ifp);
 156         if_free(ifp);
 157         free(sc, M_DEVBUF);
 158         return (0);
 159 }
 160
 161 static int
 162 enc_clone_create(struct if_clone *ifc, char *name, size_t len,
 163     struct ifc_data *ifd, struct ifnet **ifpp)
 164 {
 165         struct ifnet *ifp;
 166         struct enc_softc *sc;
 167
 168         sc = malloc(sizeof(struct enc_softc), M_DEVBUF, M_WAITOK | M_ZERO);
 169         ifp = sc->sc_ifp = if_alloc(IFT_ENC);
 170         if_initname(ifp, encname, ifd->unit);
 171         ifp->if_mtu = ENCMTU;
 172         ifp->if_ioctl = enc_ioctl;
 173         ifp->if_output = enc_output;
 174         ifp->if_softc = sc;
 175         if_attach(ifp);
 176         bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
 177         *ifpp = ifp;
 178         return (0);
 179 }
 180
 181 static int
 182 enc_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 183     struct route *ro)
 184 {
 185
 186         m_freem(m);
 187         return (0);
 188 }
 189
 190 static int
 191 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 192 {
 193
 194         if (cmd != SIOCSIFFLAGS)
 195                 return (EINVAL);
 196         if (ifp->if_flags & IFF_UP)
 197                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
 198         else
 199                 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
 200         return (0);
 201 }
 202
 203 static void
 204 enc_bpftap(struct ifnet *ifp, struct mbuf *m, const struct secasvar *sav,
 205     int32_t hhook_type, uint8_t enc, uint8_t af)
 206 {
 207         struct enchdr hdr;
 208
 209         if (hhook_type == HHOOK_TYPE_IPSEC_IN &&
 210             (enc & V_bpf_mask_in) == 0)
 211                 return;
 212         else if (hhook_type == HHOOK_TYPE_IPSEC_OUT &&
 213             (enc & V_bpf_mask_out) == 0)
 214                 return;
 215         if (!bpf_peers_present(ifp->if_bpf))
 216                 return;
 217         hdr.af = af;
 218         hdr.spi = sav->spi;
 219         hdr.flags = 0;
 220         if (sav->alg_enc != SADB_EALG_NONE)
 221                 hdr.flags |= M_CONF;
 222         if (sav->alg_auth != SADB_AALG_NONE)
 223                 hdr.flags |= M_AUTH;
 224         bpf_mtap2(ifp->if_bpf, &hdr, sizeof(hdr), m);
 225 }
 226
 227 /*
 228  * One helper hook function is used by any hook points.
 229  * + from hhook_type we can determine the packet direction:
 230  *   HHOOK_TYPE_IPSEC_IN or HHOOK_TYPE_IPSEC_OUT;
 231  * + from hhook_id we can determine address family: AF_INET or AF_INET6;
 232  * + udata contains pointer to enc_softc;
 233  * + ctx_data contains pointer to struct ipsec_ctx_data.
 234  */
 235 static int
 236 enc_hhook(int32_t hhook_type, int32_t hhook_id, void *udata, void *ctx_data,
 237     void *hdata, struct osd *hosd)
 238 {
 239         struct ipsec_ctx_data *ctx;
 240         struct enc_softc *sc;
 241         struct ifnet *ifp, *rcvif;
 242         struct pfil_head *ph;
 243         int pdir, ret;
 244
 245         sc = (struct enc_softc *)udata;
 246         ifp = sc->sc_ifp;
 247         if ((ifp->if_flags & IFF_UP) == 0)
 248                 return (0);
 249
 250         ctx = (struct ipsec_ctx_data *)ctx_data;
 251         /* XXX: wrong hook point was used by caller? */
 252         if (ctx->af != hhook_id)
 253                 return (EPFNOSUPPORT);
 254
 255         enc_bpftap(ifp, *ctx->mp, ctx->sav, hhook_type, ctx->enc, ctx->af);
 256         switch (hhook_type) {
 257         case HHOOK_TYPE_IPSEC_IN:
 258                 if (ctx->enc == IPSEC_ENC_BEFORE) {
 259                         /* Do accounting only once */
 260                         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
 261                         if_inc_counter(ifp, IFCOUNTER_IBYTES,
 262                             (*ctx->mp)->m_pkthdr.len);
 263                 }
 264                 if ((ctx->enc & V_filter_mask_in) == 0)
 265                         return (0); /* skip pfil processing */
 266                 pdir = PFIL_IN;
 267                 break;
 268         case HHOOK_TYPE_IPSEC_OUT:
 269                 if (ctx->enc == IPSEC_ENC_BEFORE) {
 270                         /* Do accounting only once */
 271                         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
 272                         if_inc_counter(ifp, IFCOUNTER_OBYTES,
 273                             (*ctx->mp)->m_pkthdr.len);
 274                 }
 275                 if ((ctx->enc & V_filter_mask_out) == 0)
 276                         return (0); /* skip pfil processing */
 277                 pdir = PFIL_OUT;
 278                 break;
 279         default:
 280                 return (EINVAL);
 281         }
 282
 283         switch (hhook_id) {
 284 #ifdef INET
 285         case AF_INET:
 286                 ph = V_inet_pfil_head;
 287                 break;
 288 #endif
 289 #ifdef INET6
 290         case AF_INET6:
 291                 ph = V_inet6_pfil_head;
 292                 break;
 293 #endif
 294         default:
 295                 ph = NULL;
 296         }
 297         if (ph == NULL || (pdir == PFIL_OUT && !PFIL_HOOKED_OUT(ph)) ||
 298             (pdir == PFIL_IN && !PFIL_HOOKED_IN(ph)))
 299                 return (0);
 300         /* Make a packet looks like it was received on enc(4) */
 301         rcvif = (*ctx->mp)->m_pkthdr.rcvif;
 302         (*ctx->mp)->m_pkthdr.rcvif = ifp;
 303         if (pdir == PFIL_IN)
 304                 ret = pfil_mbuf_in(ph, ctx->mp, ifp, ctx->inp);
 305         else
 306                 ret = pfil_mbuf_out(ph, ctx->mp, ifp, ctx->inp);
 307         if (ret != PFIL_PASS) {
 308                 *ctx->mp = NULL; /* consumed by filter */
 309                 return (EACCES);
 310         }
 311         (*ctx->mp)->m_pkthdr.rcvif = rcvif;
 312         enc_bpftap(ifp, *ctx->mp, ctx->sav, hhook_type,
 313             IPSEC_ENC_AFTER_PFIL, ctx->af);
 314         return (0);
 315 }
 316
 317 static void
 318 enc_add_hhooks(struct enc_softc *sc)
 319 {
 320         struct hookinfo hki;
 321         int error __diagused;
 322
 323         hki.hook_func = enc_hhook;
 324         hki.hook_helper = NULL;
 325         hki.hook_udata = sc;
 326 #ifdef INET
 327         hki.hook_id = AF_INET;
 328         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 329         error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET],
 330             &hki, HHOOK_WAITOK);
 331         MPASS(error == 0);
 332         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 333         error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET],
 334             &hki, HHOOK_WAITOK);
 335         MPASS(error == 0);
 336 #endif
 337 #ifdef INET6
 338         hki.hook_id = AF_INET6;
 339         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 340         error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6],
 341             &hki, HHOOK_WAITOK);
 342         MPASS(error == 0);
 343         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 344         error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6],
 345             &hki, HHOOK_WAITOK);
 346         MPASS(error == 0);
 347 #endif
 348 }
 349
 350 static void
 351 enc_remove_hhooks(struct enc_softc *sc)
 352 {
 353         struct hookinfo hki;
 354
 355         hki.hook_func = enc_hhook;
 356         hki.hook_helper = NULL;
 357         hki.hook_udata = sc;
 358 #ifdef INET
 359         hki.hook_id = AF_INET;
 360         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 361         hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET], &hki);
 362         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 363         hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET], &hki);
 364 #endif
 365 #ifdef INET6
 366         hki.hook_id = AF_INET6;
 367         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 368         hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6], &hki);
 369         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 370         hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6], &hki);
 371 #endif
 372 }
 373
 374 static void
 375 vnet_enc_init(const void *unused __unused)
 376 {
 377         struct ifnet *ifp;
 378
 379         struct if_clone_addreq req = {
 380                 .create_f = enc_clone_create,
 381                 .destroy_f = enc_clone_destroy,
 382                 .flags = IFC_F_AUTOUNIT | IFC_F_LIMITUNIT,
 383                 .maxunit = 0,
 384         };
 385         V_enc_cloner = ifc_attach_cloner(encname, &req);
 386         struct ifc_data ifd = { .unit = 0 };
 387         ifc_create_ifp(encname, &ifd, &ifp);
 388         V_enc_sc = ifp->if_softc;
 389 }
 390 VNET_SYSINIT(vnet_enc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
 391     vnet_enc_init, NULL);
 392
 393 static void
 394 vnet_enc_init_proto(void *unused __unused)
 395 {
 396         KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
 397
 398         enc_add_hhooks(V_enc_sc);
 399 }
 400 VNET_SYSINIT(vnet_enc_init_proto, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
 401     vnet_enc_init_proto, NULL);
 402
 403 static void
 404 vnet_enc_uninit(const void *unused __unused)
 405 {
 406         KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
 407
 408         ifc_detach_cloner(V_enc_cloner);
 409         V_enc_sc = NULL;
 410 }
 411 VNET_SYSUNINIT(vnet_enc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
 412     vnet_enc_uninit, NULL);
 413
 414 /*
 415  * The hhook consumer needs to go before ip[6]_destroy are called on
 416  * SI_ORDER_THIRD.
 417  */
 418 static void
 419 vnet_enc_uninit_hhook(const void *unused __unused)
 420 {
 421         KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
 422
 423         enc_remove_hhooks(V_enc_sc);
 424 }
 425 VNET_SYSUNINIT(vnet_enc_uninit_hhook, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
 426     vnet_enc_uninit_hhook, NULL);
 427
 428 static int
 429 enc_modevent(module_t mod, int type, void *data)
 430 {
 431
 432         switch (type) {
 433         case MOD_LOAD:
 434         case MOD_UNLOAD:
 435                 break;
 436         default:
 437                 return (EOPNOTSUPP);
 438         }
 439         return (0);
 440 }
 441
 442 static moduledata_t enc_mod = {
 443         "if_enc",
 444         enc_modevent,
 445         0
 446 };
 447
 448 DECLARE_MODULE(if_enc, enc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
 449 MODULE_VERSION(if_enc, 1);