FreeBSD/Linux Kernel Cross Reference
sys/net/if_enc.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2006 The FreeBSD Project.
      * Copyright (c) 2015 Andrey V. Elsukov <ae@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     *
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD: releng/12.0/sys/net/if_enc.c 336676 2018-07-24 16:35:52Z andrew $
     */
    
    #include "opt_inet.h"
    #include "opt_inet6.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/hhook.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/module.h>
    #include <machine/bus.h>
    #include <sys/rman.h>
    #include <sys/socket.h>
    #include <sys/sockio.h>
    #include <sys/sysctl.h>
    
    #include <net/if.h>
    #include <net/if_enc.h>
    #include <net/if_var.h>
    #include <net/if_clone.h>
    #include <net/if_types.h>
    #include <net/pfil.h>
    #include <net/route.h>
    #include <net/netisr.h>
    #include <net/bpf.h>
    #include <net/vnet.h>
    
    #include <netinet/in.h>
    #include <netinet/in_systm.h>
    #include <netinet/ip.h>
    #include <netinet/ip_var.h>
    #include <netinet/in_var.h>
    
    #ifdef INET6
    #include <netinet/ip6.h>
    #include <netinet6/ip6_var.h>
    #endif
    
    #include <netipsec/ipsec.h>
    #include <netipsec/xform.h>
    
    #define ENCMTU          (1024+512)
    
    /* XXX this define must have the same value as in OpenBSD */
    #define M_CONF          0x0400  /* payload was encrypted (ESP-transport) */
    #define M_AUTH          0x0800  /* payload was authenticated (AH or ESP auth) */
    #define M_AUTH_AH       0x2000  /* header was authenticated (AH) */
    
    struct enchdr {
            u_int32_t af;
            u_int32_t spi;
            u_int32_t flags;
    };
    struct enc_softc {
            struct  ifnet *sc_ifp;
    };
    VNET_DEFINE_STATIC(struct enc_softc *, enc_sc);
    #define V_enc_sc        VNET(enc_sc)
    VNET_DEFINE_STATIC(struct if_clone *, enc_cloner);
    #define V_enc_cloner    VNET(enc_cloner)
    
    static int      enc_ioctl(struct ifnet *, u_long, caddr_t);
    static int      enc_output(struct ifnet *, struct mbuf *,
        const struct sockaddr *, struct route *);
    static int      enc_clone_create(struct if_clone *, int, caddr_t);
    static void     enc_clone_destroy(struct ifnet *);
    static int      enc_add_hhooks(struct enc_softc *);
   static void     enc_remove_hhooks(struct enc_softc *);
   
   static const char encname[] = "enc";
   
   #define IPSEC_ENC_AFTER_PFIL    0x04
   /*
    * Before and after are relative to when we are stripping the
    * outer IP header.
    *
    * AFTER_PFIL flag used only for bpf_mask_*. It enables BPF capturing
    * after PFIL hook execution. It might be useful when PFIL hook does
    * some changes to the packet, e.g. address translation. If PFIL hook
    * consumes mbuf, nothing will be captured.
    */
   VNET_DEFINE_STATIC(int, filter_mask_in) = IPSEC_ENC_BEFORE;
   VNET_DEFINE_STATIC(int, bpf_mask_in) = IPSEC_ENC_BEFORE;
   VNET_DEFINE_STATIC(int, filter_mask_out) = IPSEC_ENC_BEFORE;
   VNET_DEFINE_STATIC(int, bpf_mask_out) = IPSEC_ENC_BEFORE | IPSEC_ENC_AFTER;
   #define V_filter_mask_in        VNET(filter_mask_in)
   #define V_bpf_mask_in           VNET(bpf_mask_in)
   #define V_filter_mask_out       VNET(filter_mask_out)
   #define V_bpf_mask_out          VNET(bpf_mask_out)
   
   static SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl");
   static SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl");
   static SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl");
   SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask,
       CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_in), 0,
       "IPsec input firewall filter mask");
   SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask,
       CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_in), 0,
       "IPsec input bpf mask");
   SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask,
       CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(filter_mask_out), 0,
       "IPsec output firewall filter mask");
   SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask,
       CTLFLAG_RW | CTLFLAG_VNET, &VNET_NAME(bpf_mask_out), 0,
       "IPsec output bpf mask");
   
   static void
   enc_clone_destroy(struct ifnet *ifp)
   {
           struct enc_softc *sc;
   
           sc = ifp->if_softc;
           KASSERT(sc == V_enc_sc, ("sc != ifp->if_softc"));
   
           bpfdetach(ifp);
           if_detach(ifp);
           if_free(ifp);
           free(sc, M_DEVBUF);
           V_enc_sc = NULL;
   }
   
   static int
   enc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
   {
           struct ifnet *ifp;
           struct enc_softc *sc;
   
           sc = malloc(sizeof(struct enc_softc), M_DEVBUF,
               M_WAITOK | M_ZERO);
           ifp = sc->sc_ifp = if_alloc(IFT_ENC);
           if (ifp == NULL) {
                   free(sc, M_DEVBUF);
                   return (ENOSPC);
           }
           if (V_enc_sc != NULL) {
                   if_free(ifp);
                   free(sc, M_DEVBUF);
                   return (EEXIST);
           }
           V_enc_sc = sc;
           if_initname(ifp, encname, unit);
           ifp->if_mtu = ENCMTU;
           ifp->if_ioctl = enc_ioctl;
           ifp->if_output = enc_output;
           ifp->if_softc = sc;
           if_attach(ifp);
           bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
           return (0);
   }
   
   static int
   enc_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
       struct route *ro)
   {
   
           m_freem(m);
           return (0);
   }
   
   static int
   enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
   {
   
           if (cmd != SIOCSIFFLAGS)
                   return (EINVAL);
           if (ifp->if_flags & IFF_UP)
                   ifp->if_drv_flags |= IFF_DRV_RUNNING;
           else
                   ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
           return (0);
   }
   
   static void
   enc_bpftap(struct ifnet *ifp, struct mbuf *m, const struct secasvar *sav,
       int32_t hhook_type, uint8_t enc, uint8_t af)
   {
           struct enchdr hdr;
   
           if (hhook_type == HHOOK_TYPE_IPSEC_IN &&
               (enc & V_bpf_mask_in) == 0)
                   return;
           else if (hhook_type == HHOOK_TYPE_IPSEC_OUT &&
               (enc & V_bpf_mask_out) == 0)
                   return;
           if (bpf_peers_present(ifp->if_bpf) == 0)
                   return;
           hdr.af = af;
           hdr.spi = sav->spi;
           hdr.flags = 0;
           if (sav->alg_enc != SADB_EALG_NONE)
                   hdr.flags |= M_CONF;
           if (sav->alg_auth != SADB_AALG_NONE)
                   hdr.flags |= M_AUTH;
           bpf_mtap2(ifp->if_bpf, &hdr, sizeof(hdr), m);
   }
   
   /*
    * One helper hook function is used by any hook points.
    * + from hhook_type we can determine the packet direction:
    *   HHOOK_TYPE_IPSEC_IN or HHOOK_TYPE_IPSEC_OUT;
    * + from hhook_id we can determine address family: AF_INET or AF_INET6;
    * + udata contains pointer to enc_softc;
    * + ctx_data contains pointer to struct ipsec_ctx_data.
    */
   static int
   enc_hhook(int32_t hhook_type, int32_t hhook_id, void *udata, void *ctx_data,
       void *hdata, struct osd *hosd)
   {
           struct ipsec_ctx_data *ctx;
           struct enc_softc *sc;
           struct ifnet *ifp, *rcvif;
           struct pfil_head *ph;
           int pdir;
   
           sc = (struct enc_softc *)udata;
           ifp = sc->sc_ifp;
           if ((ifp->if_flags & IFF_UP) == 0)
                   return (0);
   
           ctx = (struct ipsec_ctx_data *)ctx_data;
           /* XXX: wrong hook point was used by caller? */
           if (ctx->af != hhook_id)
                   return (EPFNOSUPPORT);
   
           enc_bpftap(ifp, *ctx->mp, ctx->sav, hhook_type, ctx->enc, ctx->af);
           switch (hhook_type) {
           case HHOOK_TYPE_IPSEC_IN:
                   if (ctx->enc == IPSEC_ENC_BEFORE) {
                           /* Do accounting only once */
                           if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
                           if_inc_counter(ifp, IFCOUNTER_IBYTES,
                               (*ctx->mp)->m_pkthdr.len);
                   }
                   if ((ctx->enc & V_filter_mask_in) == 0)
                           return (0); /* skip pfil processing */
                   pdir = PFIL_IN;
                   break;
           case HHOOK_TYPE_IPSEC_OUT:
                   if (ctx->enc == IPSEC_ENC_BEFORE) {
                           /* Do accounting only once */
                           if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
                           if_inc_counter(ifp, IFCOUNTER_OBYTES,
                               (*ctx->mp)->m_pkthdr.len);
                   }
                   if ((ctx->enc & V_filter_mask_out) == 0)
                           return (0); /* skip pfil processing */
                   pdir = PFIL_OUT;
                   break;
           default:
                   return (EINVAL);
           }
   
           switch (hhook_id) {
   #ifdef INET
           case AF_INET:
                   ph = &V_inet_pfil_hook;
                   break;
   #endif
   #ifdef INET6
           case AF_INET6:
                   ph = &V_inet6_pfil_hook;
                   break;
   #endif
           default:
                   ph = NULL;
           }
           if (ph == NULL || !PFIL_HOOKED(ph))
                   return (0);
           /* Make a packet looks like it was received on enc(4) */
           rcvif = (*ctx->mp)->m_pkthdr.rcvif;
           (*ctx->mp)->m_pkthdr.rcvif = ifp;
           if (pfil_run_hooks(ph, ctx->mp, ifp, pdir, 0, ctx->inp) != 0 ||
               *ctx->mp == NULL) {
                   *ctx->mp = NULL; /* consumed by filter */
                   return (EACCES);
           }
           (*ctx->mp)->m_pkthdr.rcvif = rcvif;
           enc_bpftap(ifp, *ctx->mp, ctx->sav, hhook_type,
               IPSEC_ENC_AFTER_PFIL, ctx->af);
           return (0);
   }
   
   static int
   enc_add_hhooks(struct enc_softc *sc)
   {
           struct hookinfo hki;
           int error;
   
           error = EPFNOSUPPORT;
           hki.hook_func = enc_hhook;
           hki.hook_helper = NULL;
           hki.hook_udata = sc;
   #ifdef INET
           hki.hook_id = AF_INET;
           hki.hook_type = HHOOK_TYPE_IPSEC_IN;
           error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET],
               &hki, HHOOK_WAITOK);
           if (error != 0)
                   return (error);
           hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
           error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET],
               &hki, HHOOK_WAITOK);
           if (error != 0)
                   return (error);
   #endif
   #ifdef INET6
           hki.hook_id = AF_INET6;
           hki.hook_type = HHOOK_TYPE_IPSEC_IN;
           error = hhook_add_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6],
               &hki, HHOOK_WAITOK);
           if (error != 0)
                   return (error);
           hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
           error = hhook_add_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6],
               &hki, HHOOK_WAITOK);
           if (error != 0)
                   return (error);
   #endif
           return (error);
   }
   
   static void
   enc_remove_hhooks(struct enc_softc *sc)
   {
           struct hookinfo hki;
   
           hki.hook_func = enc_hhook;
           hki.hook_helper = NULL;
           hki.hook_udata = sc;
   #ifdef INET
           hki.hook_id = AF_INET;
           hki.hook_type = HHOOK_TYPE_IPSEC_IN;
           hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET], &hki);
           hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
           hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET], &hki);
   #endif
   #ifdef INET6
           hki.hook_id = AF_INET6;
           hki.hook_type = HHOOK_TYPE_IPSEC_IN;
           hhook_remove_hook(V_ipsec_hhh_in[HHOOK_IPSEC_INET6], &hki);
           hki.hook_type = HHOOK_TYPE_IPSEC_OUT;
           hhook_remove_hook(V_ipsec_hhh_out[HHOOK_IPSEC_INET6], &hki);
   #endif
   }
   
   static void
   vnet_enc_init(const void *unused __unused)
   {
   
           V_enc_sc = NULL;
           V_enc_cloner = if_clone_simple(encname, enc_clone_create,
               enc_clone_destroy, 1);
   }
   VNET_SYSINIT(vnet_enc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
       vnet_enc_init, NULL);
   
   static void
   vnet_enc_init_proto(void *unused __unused)
   {
           KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
   
           if (enc_add_hhooks(V_enc_sc) != 0)
                   enc_clone_destroy(V_enc_sc->sc_ifp);
   }
   VNET_SYSINIT(vnet_enc_init_proto, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
       vnet_enc_init_proto, NULL);
   
   static void
   vnet_enc_uninit(const void *unused __unused)
   {
           KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
   
           if_clone_detach(V_enc_cloner);
   }
   VNET_SYSUNINIT(vnet_enc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
       vnet_enc_uninit, NULL);
   
   /*
    * The hhook consumer needs to go before ip[6]_destroy are called on
    * SI_ORDER_THIRD.
    */
   static void
   vnet_enc_uninit_hhook(const void *unused __unused)
   {
           KASSERT(V_enc_sc != NULL, ("%s: V_enc_sc is %p\n", __func__, V_enc_sc));
   
           enc_remove_hhooks(V_enc_sc);
   }
   VNET_SYSUNINIT(vnet_enc_uninit_hhook, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
       vnet_enc_uninit_hhook, NULL);
   
   static int
   enc_modevent(module_t mod, int type, void *data)
   {
   
           switch (type) {
           case MOD_LOAD:
           case MOD_UNLOAD:
                   break;
           default:
                   return (EOPNOTSUPP);
           }
           return (0);
   }
   
   static moduledata_t enc_mod = {
           "if_enc",
           enc_modevent,
           0
   };
   
   DECLARE_MODULE(if_enc, enc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
   MODULE_VERSION(if_enc, 1);

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