diff options
author | thompsa <thompsa@FreeBSD.org> | 2006-06-26 22:30:08 +0000 |
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committer | thompsa <thompsa@FreeBSD.org> | 2006-06-26 22:30:08 +0000 |
commit | 320c8e5164d793a94bf5d538add0abe0d4f665ca (patch) | |
tree | ad08e122ba3a5390ec867d258e80d618c4727731 /sys/net/if_enc.c | |
parent | f0555f2de979cc15b2f5899edf00461f6d7ead98 (diff) | |
download | FreeBSD-src-320c8e5164d793a94bf5d538add0abe0d4f665ca.zip FreeBSD-src-320c8e5164d793a94bf5d538add0abe0d4f665ca.tar.gz |
Add a pseudo interface for packet filtering IPSec connections before or after
encryption. There are two functions, a bpf tap which has a basic header with
the SPI number which our current tcpdump knows how to display, and handoff to
pfil(9) for packet filtering.
Obtained from: OpenBSD
Based on: kern/94829
No objections: arch, net
MFC after: 1 month
Diffstat (limited to 'sys/net/if_enc.c')
-rw-r--r-- | sys/net/if_enc.c | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/sys/net/if_enc.c b/sys/net/if_enc.c new file mode 100644 index 0000000..0aaf4aa --- /dev/null +++ b/sys/net/if_enc.c @@ -0,0 +1,323 @@ +/*- + * Copyright (c) 2006 The FreeBSD Project. + * 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. + * + * $FreeBSD$ + */ + +#include <sys/param.h> +#include <sys/systm.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_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/bpfdesc.h> + +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/ip.h> +#include <netinet/ip_var.h> +#include <netinet/in_var.h> +#include "opt_inet6.h" + +#ifdef INET6 +#include <netinet/ip6.h> +#include <netinet6/ip6_var.h> +#endif + +#include <netipsec/ipsec.h> + +#define ENCMTU (1024+512) +#define ENC_HDRLEN 12 + +/* 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; +}; + +static struct ifnet *encif; +static struct mtx enc_mtx; + +struct enc_softc { + struct ifnet *sc_ifp; +}; + +static int enc_ioctl(struct ifnet *, u_long, caddr_t); +static int enc_output(struct ifnet *ifp, struct mbuf *m, + struct sockaddr *dst, struct rtentry *rt); +static int enc_clone_create(struct if_clone *, int); +static void enc_clone_destroy(struct ifnet *); + +IFC_SIMPLE_DECLARE(enc, 1); + +static void +enc_clone_destroy(struct ifnet *ifp) +{ + + KASSERT(encif == ifp, ("%s: unknown ifnet", __func__)); + + mtx_lock(&enc_mtx); + encif = NULL; + mtx_unlock(&enc_mtx); + + bpfdetach(ifp); + if_detach(ifp); + if_free(ifp); + +} + +static int +enc_clone_create(struct if_clone *ifc, int unit) +{ + struct ifnet *ifp; + struct enc_softc *sc; + + mtx_lock(&enc_mtx); + if (encif != NULL) + return (EBUSY); + mtx_unlock(&enc_mtx); + + sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO); + ifp = sc->sc_ifp = if_alloc(IFT_ENC); + if (ifp == NULL) { + free(sc, M_DEVBUF); + return (ENOSPC); + } + + if_initname(ifp, ifc->ifc_name, unit); + ifp->if_mtu = ENCMTU; + ifp->if_ioctl = enc_ioctl; + ifp->if_output = enc_output; + ifp->if_snd.ifq_maxlen = ifqmaxlen; + ifp->if_softc = sc; + if_attach(ifp); + bpfattach(ifp, DLT_ENC, ENC_HDRLEN); + + mtx_lock(&enc_mtx); + encif = ifp; + mtx_unlock(&enc_mtx); + + return (0); +} + +static int +enc_modevent(module_t mod, int type, void *data) +{ + switch (type) { + case MOD_LOAD: + mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF); + if_clone_attach(&enc_cloner); + break; + case MOD_UNLOAD: + printf("enc module unload - not possible for this module\n"); + return (EINVAL); + default: + return (EOPNOTSUPP); + } + return (0); +} + +static moduledata_t enc_mod = { + "enc", + enc_modevent, + 0 +}; + +DECLARE_MODULE(enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY); + +static int +enc_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, + struct rtentry *rt) +{ + m_freem(m); + return (0); +} + +/* + * Process an ioctl request. + */ +/* ARGSUSED */ +static int +enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) +{ + int error = 0; + + switch (cmd) { + + case SIOCSIFFLAGS: + if (ifp->if_flags & IFF_UP) + ifp->if_drv_flags |= IFF_DRV_RUNNING; + else + ifp->if_drv_flags &= ~IFF_DRV_RUNNING; + + break; + + default: + error = EINVAL; + } + return (error); +} + +int +ipsec_filter(struct mbuf **mp, int dir) +{ + int error, i; + struct ip *ip; + + mtx_lock(&enc_mtx); + if (encif == NULL || (encif->if_drv_flags & IFF_DRV_RUNNING) == 0) { + mtx_unlock(&enc_mtx); + return (0); + } + + /* Skip pfil(9) if no filters are loaded */ + if (!(PFIL_HOOKED(&inet_pfil_hook) +#ifdef INET6 + || PFIL_HOOKED(&inet6_pfil_hook) +#endif + )) { + mtx_unlock(&enc_mtx); + return (0); + } + + i = min((*mp)->m_pkthdr.len, max_protohdr); + if ((*mp)->m_len < i) { + *mp = m_pullup(*mp, i); + if (*mp == NULL) { + printf("%s: m_pullup failed\n", __func__); + mtx_unlock(&enc_mtx); + return (-1); + } + } + + error = 0; + ip = mtod(*mp, struct ip *); + switch (ip->ip_v) { + case 4: + /* + * before calling the firewall, swap fields the same as + * IP does. here we assume the header is contiguous + */ + ip->ip_len = ntohs(ip->ip_len); + ip->ip_off = ntohs(ip->ip_off); + + error = pfil_run_hooks(&inet_pfil_hook, mp, + encif, dir, NULL); + + if (*mp == NULL || error != 0) + break; + + /* restore byte ordering */ + ip = mtod(*mp, struct ip *); + ip->ip_len = htons(ip->ip_len); + ip->ip_off = htons(ip->ip_off); + break; + +#ifdef INET6 + case 6: + error = pfil_run_hooks(&inet6_pfil_hook, mp, + encif, dir, NULL); + break; +#endif + default: + printf("%s: unknown IP version\n", __func__); + } + + mtx_unlock(&enc_mtx); + if (*mp == NULL) + return (error); + if (error != 0) + goto bad; + + return (error); + +bad: + mtx_unlock(&enc_mtx); + m_freem(*mp); + *mp = NULL; + return (error); +} + +void +ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af) +{ + int flags; + struct enchdr hdr; + struct mbuf m1; + + KASSERT(sav != NULL, ("%s: sav is null", __func__)); + + mtx_lock(&enc_mtx); + if (encif == NULL || (encif->if_drv_flags & IFF_DRV_RUNNING) == 0) { + mtx_unlock(&enc_mtx); + return; + } + + if (encif->if_bpf) { + flags = 0; + if (sav->alg_enc != SADB_EALG_NONE) + flags |= M_CONF; + if (sav->alg_auth != SADB_AALG_NONE) + flags |= M_AUTH; + + /* + * We need to prepend the address family as a four byte + * field. Cons up a dummy header to pacify bpf. This + * is safe because bpf will only read from the mbuf + * (i.e., it won't try to free it or keep a pointer a + * to it). + */ + hdr.af = af; + hdr.spi = sav->spi; + hdr.flags = flags; + + m1.m_flags = 0; + m1.m_next = m; + m1.m_len = ENC_HDRLEN; + m1.m_data = (char *) &hdr; + + bpf_mtap(encif->if_bpf, &m1); + } + mtx_unlock(&enc_mtx); +} |