sys/net/if_enc.c

   1 /*-
   2  * Copyright (c) 2006 The FreeBSD Project.
   3  * Copyright (c) 2015 Andrey V. Elsukov <ae@FreeBSD.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD$
  29  */
  30
  31 #include "opt_inet.h"
  32 #include "opt_inet6.h"
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/hhook.h>
  37 #include <sys/kernel.h>
  38 #include <sys/malloc.h>
  39 #include <sys/mbuf.h>
  40 #include <sys/module.h>
  41 #include <machine/bus.h>
  42 #include <sys/rman.h>
  43 #include <sys/socket.h>
  44 #include <sys/sockio.h>
  45 #include <sys/sysctl.h>
  46
  47 #include <net/if.h>
  48 #include <net/if_enc.h>
  49 #include <net/if_var.h>
  50 #include <net/if_clone.h>
  51 #include <net/if_types.h>
  52 #include <net/pfil.h>
  53 #include <net/route.h>
  54 #include <net/netisr.h>
  55 #include <net/bpf.h>
  56 #include <net/vnet.h>
  57
  58 #include <netinet/in.h>
  59 #include <netinet/in_systm.h>
  60 #include <netinet/ip.h>
  61 #include <netinet/ip_var.h>
  62 #include <netinet/in_var.h>
  63
  64 #ifdef INET6
  65 #include <netinet/ip6.h>
  66 #include <netinet6/ip6_var.h>
  67 #endif
  68
  69 #include <netipsec/ipsec.h>
  70 #include <netipsec/xform.h>
  71
  72 #define ENCMTU          (1024+512)
  73
  74 /* XXX this define must have the same value as in OpenBSD */
  75 #define M_CONF          0x0400  /* payload was encrypted (ESP-transport) */
  76 #define M_AUTH          0x0800  /* payload was authenticated (AH or ESP auth) */
  77 #define M_AUTH_AH       0x2000  /* header was authenticated (AH) */
  78
  79 struct enchdr {
  80         u_int32_t af;
  81         u_int32_t spi;
  82         u_int32_t flags;
  83 };
  84 struct enc_softc {
  85         struct  ifnet *sc_ifp;
  86 };
  87 static VNET_DEFINE(struct enc_softc *, enc_sc);
  88 #define V_enc_sc        VNET(enc_sc)
  89 static VNET_DEFINE(struct if_clone *, enc_cloner);
  90 #define V_enc_cloner    VNET(enc_cloner)
  91
  92 static int      enc_ioctl(struct ifnet *, u_long, caddr_t);
  93 static int      enc_output(struct ifnet *, struct mbuf *,
  94     const struct sockaddr *, struct route *);
  95 static int      enc_clone_create(struct if_clone *, int, caddr_t);
  96 static void     enc_clone_destroy(struct ifnet *);
  97 static int      enc_add_hhooks(struct enc_softc *);
  98 static void     enc_remove_hhooks(struct enc_softc *);
  99
 100 static const char encname[] = "enc";
 101
 102 /*
 103  * Before and after are relative to when we are stripping the
 104  * outer IP header.
 105  */
 106 static VNET_DEFINE(int, filter_mask_in) = IPSEC_ENC_BEFORE;
 107 static VNET_DEFINE(int, bpf_mask_in) = IPSEC_ENC_BEFORE;
 108 static VNET_DEFINE(int, filter_mask_out) = IPSEC_ENC_BEFORE;
 109 static VNET_DEFINE(int, bpf_mask_out) = IPSEC_ENC_BEFORE | IPSEC_ENC_AFTER;
 110 #define V_filter_mask_in        VNET(filter_mask_in)
 111 #define V_bpf_mask_in           VNET(bpf_mask_in)
 112 #define V_filter_mask_out       VNET(filter_mask_out)
 113 #define V_bpf_mask_out          VNET(bpf_mask_out)
 114
 115 static SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl");
 116 static SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl");
 117 static SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl");
 118 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask,
 119     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_in), 0,
 120     "IPsec input firewall filter mask");
 121 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask,
 122     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_in), 0,
 123     "IPsec input bpf mask");
 124 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask,
 125     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_out), 0,
 126     "IPsec output firewall filter mask");
 127 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask,
 128     CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_out), 0,
 129     "IPsec output bpf mask");
 130
 131 static void
 132 enc_clone_destroy(struct ifnet *ifp)
 133 {
 134         struct enc_softc *sc;
 135
 136         sc = ifp->if_softc;
 137         KASSERT(sc == V_enc_sc, ("sc != ifp->if_softc"));
 138
 139         enc_remove_hhooks(sc);
 140         bpfdetach(ifp);
 141         if_detach(ifp);
 142         if_free(ifp);
 143         free(sc, M_DEVBUF);
 144         V_enc_sc = NULL;
 145 }
 146
 147 static int
 148 enc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
 149 {
 150         struct ifnet *ifp;
 151         struct enc_softc *sc;
 152
 153         sc = malloc(sizeof(struct enc_softc), M_DEVBUF,
 154             M_WAITOK | M_ZERO);
 155         ifp = sc->sc_ifp = if_alloc(IFT_ENC);
 156         if (ifp == NULL) {
 157                 free(sc, M_DEVBUF);
 158                 return (ENOSPC);
 159         }
 160         if (V_enc_sc != NULL) {
 161                 if_free(ifp);
 162                 free(sc, M_DEVBUF);
 163                 return (EEXIST);
 164         }
 165         V_enc_sc = sc;
 166         if_initname(ifp, encname, unit);
 167         ifp->if_mtu = ENCMTU;
 168         ifp->if_ioctl = enc_ioctl;
 169         ifp->if_output = enc_output;
 170         ifp->if_softc = sc;
 171         if_attach(ifp);
 172         bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
 173         if (enc_add_hhooks(sc) != 0) {
 174                 enc_clone_destroy(ifp);
 175                 return (ENXIO);
 176         }
 177         return (0);
 178 }
 179
 180 static int
 181 enc_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 182     struct route *ro)
 183 {
 184
 185         m_freem(m);
 186         return (0);
 187 }
 188
 189 static int
 190 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 191 {
 192
 193         if (cmd != SIOCSIFFLAGS)
 194                 return (EINVAL);
 195         if (ifp->if_flags & IFF_UP)
 196                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
 197         else
 198                 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
 199         return (0);
 200 }
 201
 202 /*
 203  * One helper hook function is used by any hook points.
 204  * + from hhook_type we can determine the packet direction:
 205  *   HHOOK_TYPE_IPSEC_IN or HHOOK_TYPE_IPSEC_OUT;
 206  * + from hhook_id we can determine address family: AF_INET or AF_INET6;
 207  * + udata contains pointer to enc_softc;
 208  * + ctx_data contains pointer to struct ipsec_ctx_data.
 209  */
 210 static int
 211 enc_hhook(int32_t hhook_type, int32_t hhook_id, void *udata, void *ctx_data,
 212     void *hdata, struct osd *hosd)
 213 {
 214         struct enchdr hdr;
 215         struct ipsec_ctx_data *ctx;
 216         struct enc_softc *sc;
 217         struct ifnet *ifp, *rcvif;
 218         struct pfil_head *ph;
 219         int pdir;
 220
 221         sc = (struct enc_softc *)udata;
 222         ifp = sc->sc_ifp;
 223         if ((ifp->if_flags & IFF_UP) == 0)
 224                 return (0);
 225
 226         ctx = (struct ipsec_ctx_data *)ctx_data;
 227         /* XXX: wrong hook point was used by caller? */
 228         if (ctx->af != hhook_id)
 229                 return (EPFNOSUPPORT);
 230
 231         if (((hhook_type == HHOOK_TYPE_IPSEC_IN &&
 232             (ctx->enc & V_bpf_mask_in) != 0) ||
 233             (hhook_type == HHOOK_TYPE_IPSEC_OUT &&
 234             (ctx->enc & V_bpf_mask_out) != 0)) &&
 235             bpf_peers_present(ifp->if_bpf) != 0) {
 236                 hdr.af = ctx->af;
 237                 hdr.spi = ctx->sav->spi;
 238                 hdr.flags = 0;
 239                 if (ctx->sav->alg_enc != SADB_EALG_NONE)
 240                         hdr.flags |= M_CONF;
 241                 if (ctx->sav->alg_auth != SADB_AALG_NONE)
 242                         hdr.flags |= M_AUTH;
 243                 bpf_mtap2(ifp->if_bpf, &hdr, sizeof(hdr), *ctx->mp);
 244         }
 245
 246         switch (hhook_type) {
 247         case HHOOK_TYPE_IPSEC_IN:
 248                 if (ctx->enc == IPSEC_ENC_BEFORE) {
 249                         /* Do accounting only once */
 250                         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
 251                         if_inc_counter(ifp, IFCOUNTER_IBYTES,
 252                             (*ctx->mp)->m_pkthdr.len);
 253                 }
 254                 if ((ctx->enc & V_filter_mask_in) == 0)
 255                         return (0); /* skip pfil processing */
 256                 pdir = PFIL_IN;
 257                 break;
 258         case HHOOK_TYPE_IPSEC_OUT:
 259                 if (ctx->enc == IPSEC_ENC_BEFORE) {
 260                         /* Do accounting only once */
 261                         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
 262                         if_inc_counter(ifp, IFCOUNTER_OBYTES,
 263                             (*ctx->mp)->m_pkthdr.len);
 264                 }
 265                 if ((ctx->enc & V_filter_mask_out) == 0)
 266                         return (0); /* skip pfil processing */
 267                 pdir = PFIL_OUT;
 268                 break;
 269         default:
 270                 return (EINVAL);
 271         }
 272
 273         switch (hhook_id) {
 274 #ifdef INET
 275         case AF_INET:
 276                 ph = &V_inet_pfil_hook;
 277                 break;
 278 #endif
 279 #ifdef INET6
 280         case AF_INET6:
 281                 ph = &V_inet6_pfil_hook;
 282                 break;
 283 #endif
 284         default:
 285                 ph = NULL;
 286         }
 287         if (ph == NULL || !PFIL_HOOKED(ph))
 288                 return (0);
 289         /* Make a packet looks like it was received on enc(4) */
 290         rcvif = (*ctx->mp)->m_pkthdr.rcvif;
 291         (*ctx->mp)->m_pkthdr.rcvif = ifp;
 292         if (pfil_run_hooks(ph, ctx->mp, ifp, pdir, NULL) != 0 ||
 293             *ctx->mp == NULL) {
 294                 *ctx->mp = NULL; /* consumed by filter */
 295                 return (EACCES);
 296         }
 297         (*ctx->mp)->m_pkthdr.rcvif = rcvif;
 298         return (0);
 299 }
 300
 301 static int
 302 enc_add_hhooks(struct enc_softc *sc)
 303 {
 304         struct hookinfo hki;
 305         int error;
 306
 307         error = EPFNOSUPPORT;
 308         hki.hook_func = enc_hhook;
 309         hki.hook_helper = NULL;
 310         hki.hook_udata = sc;
 311 #ifdef INET
 312         hki.hook_id = AF_INET;
 313         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 314         error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET],
 315             &hki, HHOOK_WAITOK);
 316         if (error != 0)
 317                 return (error);
 318         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 319         error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET],
 320             &hki, HHOOK_WAITOK);
 321         if (error != 0)
 322                 return (error);
 323 #endif
 324 #ifdef INET6
 325         hki.hook_id = AF_INET6;
 326         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 327         error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6],
 328             &hki, HHOOK_WAITOK);
 329         if (error != 0)
 330                 return (error);
 331         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 332         error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6],
 333             &hki, HHOOK_WAITOK);
 334         if (error != 0)
 335                 return (error);
 336 #endif
 337         return (error);
 338 }
 339
 340 static void
 341 enc_remove_hhooks(struct enc_softc *sc)
 342 {
 343         struct hookinfo hki;
 344
 345         hki.hook_func = enc_hhook;
 346         hki.hook_helper = NULL;
 347         hki.hook_udata = sc;
 348 #ifdef INET
 349         hki.hook_id = AF_INET;
 350         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 351         hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET], &hki);
 352         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 353         hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET], &hki);
 354 #endif
 355 #ifdef INET6
 356         hki.hook_id = AF_INET6;
 357         hki.hook_type = HHOOK_TYPE_IPSEC_IN;
 358         hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6], &hki);
 359         hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
 360         hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6], &hki);
 361 #endif
 362 }
 363
 364 static void
 365 vnet_enc_init(const void *unused __unused)
 366 {
 367
 368         V_enc_sc = NULL;
 369         V_enc_cloner = if_clone_simple(encname, enc_clone_create,
 370             enc_clone_destroy, 1);
 371 }
 372 VNET_SYSINIT(vnet_enc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
 373     vnet_enc_init, NULL);
 374
 375 static void
 376 vnet_enc_uninit(const void *unused __unused)
 377 {
 378
 379         if_clone_detach(V_enc_cloner);
 380 }
 381 VNET_SYSUNINIT(vnet_enc_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
 382     vnet_enc_uninit, NULL);
 383
 384 static int
 385 enc_modevent(module_t mod, int type, void *data)
 386 {
 387
 388         switch (type) {
 389         case MOD_LOAD:
 390         case MOD_UNLOAD:
 391                 break;
 392         default:
 393                 return (EOPNOTSUPP);
 394         }
 395         return (0);
 396 }
 397
 398 static moduledata_t enc_mod = {
 399         "if_enc",
 400         enc_modevent,
 401         0
 402 };
 403
 404 DECLARE_MODULE(if_enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);