Commit IPv6 support for FAST_IPSEC to the tree.

This commit includes only the kernel files, the rest of the files
will follow in a second commit.

Reviewed by:    bz
Approved by:    re
Supported by:   Secure Computing

1 files changed, 369 insertions, 0 deletions

diff --git a/sys/netinet6/ip6_ipsec.c b/sys/netinet6/ip6_ipsec.c
new file mode 100644
index 0000000..f1c529f
--- /dev/null
+++ b/sys/netinet6/ip6_ipsec.c
@@ -0,0 +1,369 @@
+/*-
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *      The Regents of the University of California.  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.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 "opt_ipsec.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/mac.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/sysctl.h>
+
+#include <net/if.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#include <netinet/in_pcb.h>
+#include <netinet/ip_var.h>
+#include <netinet/ip_options.h>
+
+#include <machine/in_cksum.h>
+
+#ifdef FAST_IPSEC
+#include <netipsec/ipsec.h>
+#include <netipsec/ipsec6.h>
+#include <netipsec/xform.h>
+#include <netipsec/key.h>
+#ifdef IPSEC_DEBUG
+#include <netipsec/key_debug.h>
+#else
+#define	KEYDEBUG(lev,arg)
+#endif
+#endif /*FAST_IPSEC*/
+
+#include <netinet6/ip6_ipsec.h>
+
+extern	struct protosw inet6sw[];
+
+/*
+ * Check if we have to jump over firewall processing for this packet.
+ * Called from ip_input().
+ * 1 = jump over firewall, 0 = packet goes through firewall.
+ */
+int
+ip6_ipsec_filtergif(struct mbuf *m)
+{
+#if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF)
+	/*
+	 * Bypass packet filtering for packets from a tunnel (gif).
+	 */
+	if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
+		return 1;
+#endif
+	return 0;
+}
+
+/*
+ * Check if this packet has an active SA and needs to be dropped instead
+ * of forwarded.
+ * Called from ip_input().
+ * 1 = drop packet, 0 = forward packet.
+ */
+int
+ip6_ipsec_fwd(struct mbuf *m)
+{
+#ifdef FAST_IPSEC
+	struct m_tag *mtag;
+	struct tdb_ident *tdbi;
+	struct secpolicy *sp;
+	int s, error;
+	mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
+	s = splnet();
+	if (mtag != NULL) {
+		tdbi = (struct tdb_ident *)(mtag + 1);
+		sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
+	} else {
+		sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
+					   IP_FORWARDING, &error);   
+	}
+	if (sp == NULL) {	/* NB: can happen if error */
+		splx(s);
+		/*XXX error stat???*/
+		DPRINTF(("ip_input: no SP for forwarding\n"));	/*XXX*/
+		return 1;
+	}
+
+	/*
+	 * Check security policy against packet attributes.
+	 */
+	error = ipsec_in_reject(sp, m);
+	KEY_FREESP(&sp);
+	splx(s);
+	if (error) {
+		ipstat.ips_cantforward++;
+		return 1;
+	}
+#endif /* FAST_IPSEC */
+	return 0;
+}
+
+/*
+ * Check if protocol type doesn't have a further header and do IPSEC
+ * decryption or reject right now.  Protocols with further headers get
+ * their IPSEC treatment within the protocol specific processing.
+ * Called from ip_input().
+ * 1 = drop packet, 0 = continue processing packet.
+ */
+int
+ip6_ipsec_input(struct mbuf *m, int nxt)
+
+{
+#ifdef FAST_IPSEC
+	struct m_tag *mtag;
+	struct tdb_ident *tdbi;
+	struct secpolicy *sp;
+	int s, error;
+	/*
+	 * enforce IPsec policy checking if we are seeing last header.
+	 * note that we do not visit this with protocols with pcb layer
+	 * code - like udp/tcp/raw ip.
+	 */
+	if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
+	    ipsec6_in_reject(m, NULL)) {
+
+		/*
+		 * Check if the packet has already had IPsec processing
+		 * done.  If so, then just pass it along.  This tag gets
+		 * set during AH, ESP, etc. input handling, before the
+		 * packet is returned to the ip input queue for delivery.
+		 */ 
+		mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
+		s = splnet();
+		if (mtag != NULL) {
+			tdbi = (struct tdb_ident *)(mtag + 1);
+			sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
+		} else {
+			sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
+						   IP_FORWARDING, &error);   
+		}
+		if (sp != NULL) {
+			/*
+			 * Check security policy against packet attributes.
+			 */
+			error = ipsec_in_reject(sp, m);
+			KEY_FREESP(&sp);
+		} else {
+			/* XXX error stat??? */
+			error = EINVAL;
+			DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
+			return 1;
+		}
+		splx(s);
+		if (error)
+			return 1;
+	}
+#endif /* FAST_IPSEC */
+	return 0;
+}
+
+/*
+ * Called from ip6_output().
+ * 1 = drop packet, 0 = continue processing packet,
+ * -1 = packet was reinjected and stop processing packet (FAST_IPSEC only)
+ */ 
+
+int
+ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
+		 struct ifnet **ifp, struct secpolicy **sp)
+{
+#ifdef FAST_IPSEC
+	struct tdb_ident *tdbi;
+	struct m_tag *mtag;
+	int s;
+	if (sp == NULL)
+		return 1;
+	mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
+	if (mtag != NULL) {
+		tdbi = (struct tdb_ident *)(mtag + 1);
+		*sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
+		if (*sp == NULL)
+			*error = -EINVAL;	/* force silent drop */
+		m_tag_delete(*m, mtag);
+	} else {
+		*sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
+					error, inp);
+	}
+
+	/*
+	 * There are four return cases:
+	 *    sp != NULL	 	    apply IPsec policy
+	 *    sp == NULL, error == 0	    no IPsec handling needed
+	 *    sp == NULL, error == -EINVAL  discard packet w/o error
+	 *    sp == NULL, error != 0	    discard packet, report error
+	 */
+	if (*sp != NULL) {
+		/* Loop detection, check if ipsec processing already done */
+		KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request"));
+		for (mtag = m_tag_first(*m); mtag != NULL;
+		     mtag = m_tag_next(*m, mtag)) {
+			if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
+				continue;
+			if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
+			    mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
+				continue;
+			/*
+			 * Check if policy has an SA associated with it.
+			 * This can happen when an SP has yet to acquire
+			 * an SA; e.g. on first reference.  If it occurs,
+			 * then we let ipsec4_process_packet do its thing.
+			 */
+			if ((*sp)->req->sav == NULL)
+				break;
+			tdbi = (struct tdb_ident *)(mtag + 1);
+			if (tdbi->spi == (*sp)->req->sav->spi &&
+			    tdbi->proto == (*sp)->req->sav->sah->saidx.proto &&
+			    bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst,
+				 sizeof (union sockaddr_union)) == 0) {
+				/*
+				 * No IPsec processing is needed, free
+				 * reference to SP.
+				 *
+				 * NB: null pointer to avoid free at
+				 *     done: below.
+				 */
+				KEY_FREESP(sp), sp = NULL;
+				splx(s);
+				goto done;
+			}
+		}
+
+		/*
+		 * Do delayed checksums now because we send before
+		 * this is done in the normal processing path.
+		 */
+		if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
+			in_delayed_cksum(*m);
+			(*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
+		}
+
+		/*
+		 * Preserve KAME behaviour: ENOENT can be returned
+		 * when an SA acquire is in progress.  Don't propagate
+		 * this to user-level; it confuses applications.
+		 *
+		 * XXX this will go away when the SADB is redone.
+		 */
+		if (*error == ENOENT)
+			*error = 0;
+		goto do_ipsec;
+	} else {	/* sp == NULL */
+		if (*error != 0) {
+			/*
+			 * Hack: -EINVAL is used to signal that a packet
+			 * should be silently discarded.  This is typically
+			 * because we asked key management for an SA and
+			 * it was delayed (e.g. kicked up to IKE).
+			 */
+			if (*error == -EINVAL)
+				*error = 0;
+			goto bad;
+		} else {
+			/* No IPsec processing for this packet. */
+		}
+	}
+done:
+	if (sp != NULL)
+		if (*sp != NULL)
+			KEY_FREESP(sp);
+	return 0;
+do_ipsec:
+	return -1;
+bad:
+	if (sp != NULL)
+		if (*sp != NULL)
+			KEY_FREESP(sp);
+	return 1;
+#endif /* FAST_IPSEC */
+	return 0;
+}
+
+/*
+ * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
+ * Called from ip_forward().
+ * Returns MTU suggestion for ICMP needfrag reply.
+ */
+int
+ip6_ipsec_mtu(struct mbuf *m)
+{
+	int mtu = 0;
+	/*
+	 * If the packet is routed over IPsec tunnel, tell the
+	 * originator the tunnel MTU.
+	 *	tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
+	 * XXX quickhack!!!
+	 */
+	struct secpolicy *sp = NULL;
+	int ipsecerror;
+	int ipsechdr;
+	struct route *ro;
+#ifdef FAST_IPSEC
+	sp = ipsec_getpolicybyaddr(m,
+				   IPSEC_DIR_OUTBOUND,
+				   IP_FORWARDING,
+				   &ipsecerror);
+#endif /* FAST_IPSEC */
+	if (sp != NULL) {
+		/* count IPsec header size */
+		ipsechdr = ipsec4_hdrsiz(m,
+					 IPSEC_DIR_OUTBOUND,
+					 NULL);
+
+		/*
+		 * find the correct route for outer IPv4
+		 * header, compute tunnel MTU.
+		 */
+		if (sp->req != NULL &&
+		    sp->req->sav != NULL &&
+		    sp->req->sav->sah != NULL) {
+			ro = &sp->req->sav->sah->sa_route;
+			if (ro->ro_rt && ro->ro_rt->rt_ifp) {
+				mtu =
+				    ro->ro_rt->rt_rmx.rmx_mtu ?
+				    ro->ro_rt->rt_rmx.rmx_mtu :
+				    ro->ro_rt->rt_ifp->if_mtu;
+				mtu -= ipsechdr;
+			}
+		}
+#ifdef FAST_IPSEC
+		KEY_FREESP(&sp);
+#endif /* FAST_IPSEC */
+	}
+	return mtu;
+}
+