e361d7d421
(dummynet), ipsec_filter() would return the empty error code and the ipsec code would continue to forward/deference the null mbuf. Found by: m0n0wall Reviewed by: bz MFC after: 3 days
374 lines
8.9 KiB
C
374 lines
8.9 KiB
C
/*-
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* Copyright (c) 2006 The FreeBSD Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/module.h>
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#include <machine/bus.h>
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#include <sys/rman.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_clone.h>
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#include <net/if_types.h>
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#include <net/pfil.h>
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#include <net/route.h>
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#include <net/netisr.h>
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#include <net/bpf.h>
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#include <net/bpfdesc.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/in_var.h>
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#include "opt_inet6.h"
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#ifdef INET6
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#include <netinet/ip6.h>
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#include <netinet6/ip6_var.h>
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#endif
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#include "opt_enc.h"
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#include <netipsec/ipsec.h>
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#include <netipsec/xform.h>
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#define ENCMTU (1024+512)
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/* XXX this define must have the same value as in OpenBSD */
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#define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */
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#define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */
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#define M_AUTH_AH 0x2000 /* header was authenticated (AH) */
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struct enchdr {
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u_int32_t af;
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u_int32_t spi;
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u_int32_t flags;
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};
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static struct ifnet *encif;
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static struct mtx enc_mtx;
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struct enc_softc {
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struct ifnet *sc_ifp;
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};
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static int enc_ioctl(struct ifnet *, u_long, caddr_t);
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static int enc_output(struct ifnet *ifp, struct mbuf *m,
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struct sockaddr *dst, struct rtentry *rt);
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static int enc_clone_create(struct if_clone *, int, caddr_t);
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static void enc_clone_destroy(struct ifnet *);
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IFC_SIMPLE_DECLARE(enc, 1);
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/*
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* Sysctls.
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*/
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/*
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* Before and after are relative to when we are stripping the
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* outer IP header.
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*/
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SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl");
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SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl");
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static int ipsec_filter_mask_in = ENC_BEFORE;
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SYSCTL_XINT(_net_enc_in, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW,
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&ipsec_filter_mask_in, 0, "IPsec input firewall filter mask");
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static int ipsec_bpf_mask_in = ENC_BEFORE;
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SYSCTL_XINT(_net_enc_in, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW,
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&ipsec_bpf_mask_in, 0, "IPsec input bpf mask");
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SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl");
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static int ipsec_filter_mask_out = ENC_BEFORE;
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SYSCTL_XINT(_net_enc_out, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW,
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&ipsec_filter_mask_out, 0, "IPsec output firewall filter mask");
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static int ipsec_bpf_mask_out = ENC_BEFORE|ENC_AFTER;
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SYSCTL_XINT(_net_enc_out, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW,
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&ipsec_bpf_mask_out, 0, "IPsec output bpf mask");
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static void
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enc_clone_destroy(struct ifnet *ifp)
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{
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KASSERT(ifp != encif, ("%s: destroying encif", __func__));
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bpfdetach(ifp);
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if_detach(ifp);
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if_free(ifp);
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}
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static int
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enc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
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{
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struct ifnet *ifp;
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struct enc_softc *sc;
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sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
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ifp = sc->sc_ifp = if_alloc(IFT_ENC);
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if (ifp == NULL) {
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free(sc, M_DEVBUF);
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return (ENOSPC);
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}
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if_initname(ifp, ifc->ifc_name, unit);
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ifp->if_mtu = ENCMTU;
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ifp->if_ioctl = enc_ioctl;
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ifp->if_output = enc_output;
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ifp->if_snd.ifq_maxlen = ifqmaxlen;
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ifp->if_softc = sc;
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if_attach(ifp);
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bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
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mtx_lock(&enc_mtx);
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/* grab a pointer to enc0, ignore the rest */
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if (encif == NULL)
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encif = ifp;
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mtx_unlock(&enc_mtx);
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return (0);
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}
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static int
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enc_modevent(module_t mod, int type, void *data)
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{
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switch (type) {
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case MOD_LOAD:
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mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF);
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if_clone_attach(&enc_cloner);
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break;
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case MOD_UNLOAD:
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printf("enc module unload - not possible for this module\n");
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return (EINVAL);
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default:
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return (EOPNOTSUPP);
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}
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return (0);
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}
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static moduledata_t enc_mod = {
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"enc",
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enc_modevent,
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0
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};
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DECLARE_MODULE(enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
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static int
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enc_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
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struct rtentry *rt)
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{
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m_freem(m);
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return (0);
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}
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/*
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* Process an ioctl request.
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*/
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/* ARGSUSED */
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static int
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enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
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{
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int error = 0;
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mtx_lock(&enc_mtx);
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switch (cmd) {
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case SIOCSIFFLAGS:
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if (ifp->if_flags & IFF_UP)
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ifp->if_drv_flags |= IFF_DRV_RUNNING;
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else
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ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
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break;
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default:
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error = EINVAL;
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}
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mtx_unlock(&enc_mtx);
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return (error);
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}
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int
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ipsec_filter(struct mbuf **mp, int dir, int flags)
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{
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int error, i;
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struct ip *ip;
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KASSERT(encif != NULL, ("%s: encif is null", __func__));
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KASSERT(flags & (ENC_IN|ENC_OUT),
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("%s: invalid flags: %04x", __func__, flags));
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if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0)
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return (0);
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if (flags & ENC_IN) {
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if ((flags & ipsec_filter_mask_in) == 0)
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return (0);
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} else {
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if ((flags & ipsec_filter_mask_out) == 0)
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return (0);
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}
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/* Skip pfil(9) if no filters are loaded */
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if (!(PFIL_HOOKED(&inet_pfil_hook)
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#ifdef INET6
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|| PFIL_HOOKED(&inet6_pfil_hook)
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#endif
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)) {
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return (0);
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}
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i = min((*mp)->m_pkthdr.len, max_protohdr);
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if ((*mp)->m_len < i) {
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*mp = m_pullup(*mp, i);
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if (*mp == NULL) {
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printf("%s: m_pullup failed\n", __func__);
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return (-1);
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}
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}
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error = 0;
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ip = mtod(*mp, struct ip *);
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switch (ip->ip_v) {
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case 4:
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/*
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* before calling the firewall, swap fields the same as
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* IP does. here we assume the header is contiguous
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*/
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ip->ip_len = ntohs(ip->ip_len);
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ip->ip_off = ntohs(ip->ip_off);
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error = pfil_run_hooks(&inet_pfil_hook, mp,
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encif, dir, NULL);
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if (*mp == NULL || error != 0)
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break;
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/* restore byte ordering */
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ip = mtod(*mp, struct ip *);
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ip->ip_len = htons(ip->ip_len);
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ip->ip_off = htons(ip->ip_off);
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break;
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#ifdef INET6
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case 6:
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error = pfil_run_hooks(&inet6_pfil_hook, mp,
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encif, dir, NULL);
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break;
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#endif
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default:
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printf("%s: unknown IP version\n", __func__);
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}
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/*
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* If the mbuf was consumed by the filter for requeueing (dummynet, etc)
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* then error will be zero but we still want to return an error to our
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* caller so the null mbuf isn't forwarded further.
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*/
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if (*mp == NULL && error == 0)
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return (-1); /* Consumed by the filter */
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if (*mp == NULL)
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return (error);
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if (error != 0)
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goto bad;
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return (error);
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bad:
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m_freem(*mp);
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*mp = NULL;
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return (error);
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}
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void
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ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af, int flags)
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{
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int mflags;
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struct enchdr hdr;
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KASSERT(encif != NULL, ("%s: encif is null", __func__));
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KASSERT(flags & (ENC_IN|ENC_OUT),
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("%s: invalid flags: %04x", __func__, flags));
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if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0)
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return;
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if (flags & ENC_IN) {
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if ((flags & ipsec_bpf_mask_in) == 0)
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return;
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} else {
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if ((flags & ipsec_bpf_mask_out) == 0)
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return;
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}
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if (bpf_peers_present(encif->if_bpf)) {
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mflags = 0;
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hdr.spi = 0;
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if (!sav) {
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struct m_tag *mtag;
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mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
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if (mtag != NULL) {
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struct tdb_ident *tdbi;
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tdbi = (struct tdb_ident *) (mtag + 1);
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if (tdbi->alg_enc != SADB_EALG_NONE)
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mflags |= M_CONF;
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if (tdbi->alg_auth != SADB_AALG_NONE)
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mflags |= M_AUTH;
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hdr.spi = tdbi->spi;
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}
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} else {
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if (sav->alg_enc != SADB_EALG_NONE)
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mflags |= M_CONF;
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if (sav->alg_auth != SADB_AALG_NONE)
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mflags |= M_AUTH;
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hdr.spi = sav->spi;
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}
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/*
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* We need to prepend the address family as a four byte
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* field. Cons up a dummy header to pacify bpf. This
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* is safe because bpf will only read from the mbuf
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* (i.e., it won't try to free it or keep a pointer a
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* to it).
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*/
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hdr.af = af;
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/* hdr.spi already set above */
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hdr.flags = mflags;
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bpf_mtap2(encif->if_bpf, &hdr, sizeof(hdr), m);
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}
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}
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