FreeBSD-5.3/sys/netipsec/xform_ipip.c
/* $FreeBSD: src/sys/netipsec/xform_ipip.c,v 1.9.2.1 2004/09/15 15:14:19 andre Exp $ */
/* $OpenBSD: ip_ipip.c,v 1.25 2002/06/10 18:04:55 itojun Exp $ */
/*
* The authors of this code are John Ioannidis (ji@tla.org),
* Angelos D. Keromytis (kermit@csd.uch.gr) and
* Niels Provos (provos@physnet.uni-hamburg.de).
*
* The original version of this code was written by John Ioannidis
* for BSD/OS in Athens, Greece, in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis.
*
* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
* and Niels Provos.
*
* Additional features in 1999 by Angelos D. Keromytis.
*
* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
* Copyright (c) 2001, Angelos D. Keromytis.
*
* Permission to use, copy, and modify this software with or without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
* You may use this code under the GNU public license if you so wish. Please
* contribute changes back to the authors under this freer than GPL license
* so that we may further the use of strong encryption without limitations to
* all.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
/*
* IP-inside-IP processing
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#include <netinet/ipprotosw.h>
#include <netipsec/ipsec.h>
#include <netipsec/xform.h>
#include <netipsec/ipip_var.h>
#ifdef MROUTING
#include <netinet/ip_mroute.h>
#endif
#ifdef INET6
#include <netinet/ip6.h>
#include <netipsec/ipsec6.h>
#include <netinet6/ip6_ecn.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6protosw.h>
#endif
#include <netipsec/key.h>
#include <netipsec/key_debug.h>
#include <machine/stdarg.h>
/*
* We can control the acceptance of IP4 packets by altering the sysctl
* net.inet.ipip.allow value. Zero means drop them, all else is acceptance.
*/
int ipip_allow = 0;
struct ipipstat ipipstat;
SYSCTL_DECL(_net_inet_ipip);
SYSCTL_INT(_net_inet_ipip, OID_AUTO,
ipip_allow, CTLFLAG_RW, &ipip_allow, 0, "");
SYSCTL_STRUCT(_net_inet_ipip, IPSECCTL_STATS,
stats, CTLFLAG_RD, &ipipstat, ipipstat, "");
/* XXX IPCOMP */
#define M_IPSEC (M_AUTHIPHDR|M_AUTHIPDGM|M_DECRYPTED)
static void _ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp);
#ifdef INET6
/*
* Really only a wrapper for ipip_input(), for use with IPv6.
*/
int
ip4_input6(struct mbuf **m, int *offp, int proto)
{
#if 0
/* If we do not accept IP-in-IP explicitly, drop. */
if (!ipip_allow && ((*m)->m_flags & M_IPSEC) == 0) {
DPRINTF(("%s: dropped due to policy\n", __func__));
ipipstat.ipips_pdrops++;
m_freem(*m);
return IPPROTO_DONE;
}
#endif
_ipip_input(*m, *offp, NULL);
return IPPROTO_DONE;
}
#endif /* INET6 */
#ifdef INET
/*
* Really only a wrapper for ipip_input(), for use with IPv4.
*/
void
ip4_input(struct mbuf *m, ...)
{
va_list ap;
int iphlen;
#if 0
/* If we do not accept IP-in-IP explicitly, drop. */
if (!ipip_allow && (m->m_flags & M_IPSEC) == 0) {
DPRINTF(("%s: dropped due to policy\n", __func__));
ipipstat.ipips_pdrops++;
m_freem(m);
return;
}
#endif
va_start(ap, m);
iphlen = va_arg(ap, int);
va_end(ap);
_ipip_input(m, iphlen, NULL);
}
#endif /* INET */
/*
* ipip_input gets called when we receive an IP{46} encapsulated packet,
* either because we got it at a real interface, or because AH or ESP
* were being used in tunnel mode (in which case the rcvif element will
* contain the address of the encX interface associated with the tunnel.
*/
static void
_ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp)
{
register struct sockaddr_in *sin;
register struct ifnet *ifp;
register struct ifaddr *ifa;
struct ip *ipo;
#ifdef INET6
register struct sockaddr_in6 *sin6;
struct ip6_hdr *ip6 = NULL;
u_int8_t itos;
#endif
u_int8_t nxt;
int isr;
u_int8_t otos;
u_int8_t v;
int hlen;
ipipstat.ipips_ipackets++;
m_copydata(m, 0, 1, &v);
switch (v >> 4) {
#ifdef INET
case 4:
hlen = sizeof(struct ip);
break;
#endif /* INET */
#ifdef INET6
case 6:
hlen = sizeof(struct ip6_hdr);
break;
#endif
default:
ipipstat.ipips_family++;
m_freem(m);
return /* EAFNOSUPPORT */;
}
/* Bring the IP header in the first mbuf, if not there already */
if (m->m_len < hlen) {
if ((m = m_pullup(m, hlen)) == NULL) {
DPRINTF(("%s: m_pullup (1) failed\n", __func__));
ipipstat.ipips_hdrops++;
return;
}
}
ipo = mtod(m, struct ip *);
#ifdef MROUTING
if (ipo->ip_v == IPVERSION && ipo->ip_p == IPPROTO_IPV4) {
if (IN_MULTICAST(((struct ip *)((char *) ipo + iphlen))->ip_dst.s_addr)) {
ipip_mroute_input (m, iphlen);
return;
}
}
#endif /* MROUTING */
/* Keep outer ecn field. */
switch (v >> 4) {
#ifdef INET
case 4:
otos = ipo->ip_tos;
break;
#endif /* INET */
#ifdef INET6
case 6:
otos = (ntohl(mtod(m, struct ip6_hdr *)->ip6_flow) >> 20) & 0xff;
break;
#endif
default:
panic("ipip_input: unknown ip version %u (outer)", v>>4);
}
/* Remove outer IP header */
m_adj(m, iphlen);
/* Sanity check */
if (m->m_pkthdr.len < sizeof(struct ip)) {
ipipstat.ipips_hdrops++;
m_freem(m);
return;
}
m_copydata(m, 0, 1, &v);
switch (v >> 4) {
#ifdef INET
case 4:
hlen = sizeof(struct ip);
break;
#endif /* INET */
#ifdef INET6
case 6:
hlen = sizeof(struct ip6_hdr);
break;
#endif
default:
ipipstat.ipips_family++;
m_freem(m);
return; /* EAFNOSUPPORT */
}
/*
* Bring the inner IP header in the first mbuf, if not there already.
*/
if (m->m_len < hlen) {
if ((m = m_pullup(m, hlen)) == NULL) {
DPRINTF(("%s: m_pullup (2) failed\n", __func__));
ipipstat.ipips_hdrops++;
return;
}
}
/*
* RFC 1853 specifies that the inner TTL should not be touched on
* decapsulation. There's no reason this comment should be here, but
* this is as good as any a position.
*/
/* Some sanity checks in the inner IP header */
switch (v >> 4) {
#ifdef INET
case 4:
ipo = mtod(m, struct ip *);
nxt = ipo->ip_p;
ip_ecn_egress(ip4_ipsec_ecn, &otos, &ipo->ip_tos);
break;
#endif /* INET */
#ifdef INET6
case 6:
ip6 = (struct ip6_hdr *) ipo;
nxt = ip6->ip6_nxt;
itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
ip_ecn_egress(ip6_ipsec_ecn, &otos, &itos);
ip6->ip6_flow &= ~htonl(0xff << 20);
ip6->ip6_flow |= htonl((u_int32_t) itos << 20);
break;
#endif
default:
panic("ipip_input: unknown ip version %u (inner)", v>>4);
}
/* Check for local address spoofing. */
if ((m->m_pkthdr.rcvif == NULL ||
!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) &&
ipip_allow != 2) {
IFNET_RLOCK();
TAILQ_FOREACH(ifp, &ifnet, if_link) {
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
#ifdef INET
if (ipo) {
if (ifa->ifa_addr->sa_family !=
AF_INET)
continue;
sin = (struct sockaddr_in *) ifa->ifa_addr;
if (sin->sin_addr.s_addr ==
ipo->ip_src.s_addr) {
ipipstat.ipips_spoof++;
m_freem(m);
IFNET_RUNLOCK();
return;
}
}
#endif /* INET */
#ifdef INET6
if (ip6) {
if (ifa->ifa_addr->sa_family !=
AF_INET6)
continue;
sin6 = (struct sockaddr_in6 *) ifa->ifa_addr;
if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip6->ip6_src)) {
ipipstat.ipips_spoof++;
m_freem(m);
IFNET_RUNLOCK();
return;
}
}
#endif /* INET6 */
}
}
IFNET_RUNLOCK();
}
/* Statistics */
ipipstat.ipips_ibytes += m->m_pkthdr.len - iphlen;
/*
* Interface pointer stays the same; if no IPsec processing has
* been done (or will be done), this will point to a normal
* interface. Otherwise, it'll point to an enc interface, which
* will allow a packet filter to distinguish between secure and
* untrusted packets.
*/
switch (v >> 4) {
#ifdef INET
case 4:
isr = NETISR_IP;
break;
#endif
#ifdef INET6
case 6:
isr = NETISR_IPV6;
break;
#endif
default:
panic("%s: bogus ip version %u", __func__, v>>4);
}
if (netisr_queue(isr, m)) { /* (0) on success. */
ipipstat.ipips_qfull++;
DPRINTF(("%s: packet dropped because of full queue\n",
__func__));
}
}
int
ipip_output(
struct mbuf *m,
struct ipsecrequest *isr,
struct mbuf **mp,
int skip,
int protoff
)
{
struct secasvar *sav;
u_int8_t tp, otos;
struct secasindex *saidx;
int error;
#ifdef INET
u_int8_t itos;
struct ip *ipo;
#endif /* INET */
#ifdef INET6
struct ip6_hdr *ip6, *ip6o;
#endif /* INET6 */
IPSEC_SPLASSERT_SOFTNET(__func__);
sav = isr->sav;
IPSEC_ASSERT(sav != NULL, ("null SA"));
IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
/* XXX Deal with empty TDB source/destination addresses. */
m_copydata(m, 0, 1, &tp);
tp = (tp >> 4) & 0xff; /* Get the IP version number. */
saidx = &sav->sah->saidx;
switch (saidx->dst.sa.sa_family) {
#ifdef INET
case AF_INET:
if (saidx->src.sa.sa_family != AF_INET ||
saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) {
DPRINTF(("%s: unspecified tunnel endpoint "
"address in SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst),
(u_long) ntohl(sav->spi)));
ipipstat.ipips_unspec++;
error = EINVAL;
goto bad;
}
M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
if (m == 0) {
DPRINTF(("%s: M_PREPEND failed\n", __func__));
ipipstat.ipips_hdrops++;
error = ENOBUFS;
goto bad;
}
ipo = mtod(m, struct ip *);
ipo->ip_v = IPVERSION;
ipo->ip_hl = 5;
ipo->ip_len = htons(m->m_pkthdr.len);
ipo->ip_ttl = ip_defttl;
ipo->ip_sum = 0;
ipo->ip_src = saidx->src.sin.sin_addr;
ipo->ip_dst = saidx->dst.sin.sin_addr;
ipo->ip_id = ip_newid();
/* If the inner protocol is IP... */
if (tp == IPVERSION) {
/* Save ECN notification */
m_copydata(m, sizeof(struct ip) +
offsetof(struct ip, ip_tos),
sizeof(u_int8_t), (caddr_t) &itos);
ipo->ip_p = IPPROTO_IPIP;
/*
* We should be keeping tunnel soft-state and
* send back ICMPs if needed.
*/
m_copydata(m, sizeof(struct ip) +
offsetof(struct ip, ip_off),
sizeof(u_int16_t), (caddr_t) &ipo->ip_off);
ipo->ip_off = ntohs(ipo->ip_off);
ipo->ip_off &= ~(IP_DF | IP_MF | IP_OFFMASK);
ipo->ip_off = htons(ipo->ip_off);
}
#ifdef INET6
else if (tp == (IPV6_VERSION >> 4)) {
u_int32_t itos32;
/* Save ECN notification. */
m_copydata(m, sizeof(struct ip) +
offsetof(struct ip6_hdr, ip6_flow),
sizeof(u_int32_t), (caddr_t) &itos32);
itos = ntohl(itos32) >> 20;
ipo->ip_p = IPPROTO_IPV6;
ipo->ip_off = 0;
}
#endif /* INET6 */
else {
goto nofamily;
}
otos = 0;
ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
ipo->ip_tos = otos;
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
if (IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr) ||
saidx->src.sa.sa_family != AF_INET6 ||
IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr)) {
DPRINTF(("%s: unspecified tunnel endpoint "
"address in SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst),
(u_long) ntohl(sav->spi)));
ipipstat.ipips_unspec++;
error = ENOBUFS;
goto bad;
}
/* scoped address handling */
ip6 = mtod(m, struct ip6_hdr *);
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
ip6->ip6_src.s6_addr16[1] = 0;
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
ip6->ip6_dst.s6_addr16[1] = 0;
M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
if (m == 0) {
DPRINTF(("%s: M_PREPEND failed\n", __func__));
ipipstat.ipips_hdrops++;
error = ENOBUFS;
goto bad;
}
/* Initialize IPv6 header */
ip6o = mtod(m, struct ip6_hdr *);
ip6o->ip6_flow = 0;
ip6o->ip6_vfc &= ~IPV6_VERSION_MASK;
ip6o->ip6_vfc |= IPV6_VERSION;
ip6o->ip6_plen = htons(m->m_pkthdr.len);
ip6o->ip6_hlim = ip_defttl;
ip6o->ip6_dst = saidx->dst.sin6.sin6_addr;
ip6o->ip6_src = saidx->src.sin6.sin6_addr;
#ifdef INET
if (tp == IPVERSION) {
/* Save ECN notification */
m_copydata(m, sizeof(struct ip6_hdr) +
offsetof(struct ip, ip_tos), sizeof(u_int8_t),
(caddr_t) &itos);
/* This is really IPVERSION. */
ip6o->ip6_nxt = IPPROTO_IPIP;
} else
#endif /* INET */
if (tp == (IPV6_VERSION >> 4)) {
u_int32_t itos32;
/* Save ECN notification. */
m_copydata(m, sizeof(struct ip6_hdr) +
offsetof(struct ip6_hdr, ip6_flow),
sizeof(u_int32_t), (caddr_t) &itos32);
itos = ntohl(itos32) >> 20;
ip6o->ip6_nxt = IPPROTO_IPV6;
} else {
goto nofamily;
}
otos = 0;
ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
ip6o->ip6_flow |= htonl((u_int32_t) otos << 20);
break;
#endif /* INET6 */
default:
nofamily:
DPRINTF(("%s: unsupported protocol family %u\n", __func__,
saidx->dst.sa.sa_family));
ipipstat.ipips_family++;
error = EAFNOSUPPORT; /* XXX diffs from openbsd */
goto bad;
}
ipipstat.ipips_opackets++;
*mp = m;
#ifdef INET
if (saidx->dst.sa.sa_family == AF_INET) {
#if 0
if (sav->tdb_xform->xf_type == XF_IP4)
tdb->tdb_cur_bytes +=
m->m_pkthdr.len - sizeof(struct ip);
#endif
ipipstat.ipips_obytes += m->m_pkthdr.len - sizeof(struct ip);
}
#endif /* INET */
#ifdef INET6
if (saidx->dst.sa.sa_family == AF_INET6) {
#if 0
if (sav->tdb_xform->xf_type == XF_IP4)
tdb->tdb_cur_bytes +=
m->m_pkthdr.len - sizeof(struct ip6_hdr);
#endif
ipipstat.ipips_obytes +=
m->m_pkthdr.len - sizeof(struct ip6_hdr);
}
#endif /* INET6 */
return 0;
bad:
if (m)
m_freem(m);
*mp = NULL;
return (error);
}
#ifdef FAST_IPSEC
static int
ipe4_init(struct secasvar *sav, struct xformsw *xsp)
{
sav->tdb_xform = xsp;
return 0;
}
static int
ipe4_zeroize(struct secasvar *sav)
{
sav->tdb_xform = NULL;
return 0;
}
static int
ipe4_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
/* This is a rather serious mistake, so no conditional printing. */
printf("%s: should never be called\n", __func__);
if (m)
m_freem(m);
return EOPNOTSUPP;
}
static struct xformsw ipe4_xformsw = {
XF_IP4, 0, "IPv4 Simple Encapsulation",
ipe4_init, ipe4_zeroize, ipe4_input, ipip_output,
};
extern struct domain inetdomain;
static struct ipprotosw ipe4_protosw[] = {
{ SOCK_RAW, &inetdomain, IPPROTO_IPV4, PR_ATOMIC|PR_ADDR|PR_LASTHDR,
(pr_in_input_t*) ip4_input,
0, 0, rip_ctloutput,
0,
0, 0, 0, 0,
&rip_usrreqs
},
#ifdef INET6
{ SOCK_RAW, &inetdomain, IPPROTO_IPV6, PR_ATOMIC|PR_ADDR|PR_LASTHDR,
(pr_in_input_t*) ip4_input,
0, 0, rip_ctloutput,
0,
0, 0, 0, 0,
&rip_usrreqs
}
#endif
};
/*
* Check the encapsulated packet to see if we want it
*/
static int
ipe4_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
{
/*
* Only take packets coming from IPSEC tunnels; the rest
* must be handled by the gif tunnel code. Note that we
* also return a minimum priority when we want the packet
* so any explicit gif tunnels take precedence.
*/
return ((m->m_flags & M_IPSEC) != 0 ? 1 : 0);
}
static void
ipe4_attach(void)
{
xform_register(&ipe4_xformsw);
/* attach to encapsulation framework */
/* XXX save return cookie for detach on module remove */
(void) encap_attach_func(AF_INET, -1,
ipe4_encapcheck, (struct protosw*) &ipe4_protosw[0], NULL);
#ifdef INET6
(void) encap_attach_func(AF_INET6, -1,
ipe4_encapcheck, (struct protosw*) &ipe4_protosw[1], NULL);
#endif
}
SYSINIT(ipe4_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ipe4_attach, NULL);
#endif /* FAST_IPSEC */