IPsec policies can be looked up based on an IP packet

src/libipsec/ipsec_policy.c

@@ -101,6 +101,18 @@ METHOD(ipsec_policy_t, match, bool,
 			this->dst_ts->equals(this->dst_ts, dst_ts));
 }
 
+METHOD(ipsec_policy_t, match_packet, bool,
+	private_ipsec_policy_t *this, ip_packet_t *packet)
+{
+	u_int8_t proto = packet->get_next_header(packet);
+	host_t *src = packet->get_source(packet),
+		   *dst = packet->get_destination(packet);
+
+	return (!this->protocol || this->protocol == proto) &&
+		   this->src_ts->includes(this->src_ts, src) &&
+		   this->dst_ts->includes(this->dst_ts, dst);
+}
+
 METHOD(ipsec_policy_t, get_source_ts, traffic_selector_t*,
 	private_ipsec_policy_t *this)
 {
@@ -172,6 +184,7 @@ ipsec_policy_t *ipsec_policy_create(host_t *src, host_t *dst,
 	INIT(this,
 		.public = {
 			.match = _match,
+			.match_packet = _match_packet,
 			.get_source_ts = _get_source_ts,
 			.get_destination_ts = _get_destination_ts,
 			.get_direction = _get_direction,

src/libipsec/ipsec_policy.h

@@ -23,6 +23,8 @@
 #ifndef IPSEC_POLICY_H
 #define IPSEC_POLICY_H
 
+#include "ip_packet.h"
+
 #include <library.h>
 #include <utils/host.h>
 #include <ipsec/ipsec_types.h>
@@ -99,6 +101,14 @@ struct ipsec_policy_t {
 				  traffic_selector_t *dst_ts, policy_dir_t direction,
 				  u_int32_t reqid, mark_t mark, policy_priority_t priority);
 
+	/**
+	 * Check if this policy matches the given IP packet
+	 *
+	 * @param packet		IP packet
+	 * @return				TRUE if policy matches the packet
+	 */
+	bool (*match_packet)(ipsec_policy_t *this, ip_packet_t *packet);
+
 	/**
 	 * Destroy an ipsec_policy_t
 	 */

src/libipsec/ipsec_policy_mgr.c

@@ -16,7 +16,6 @@
  */
 
 #include "ipsec_policy_mgr.h"
-#include "ipsec_policy.h"
 
 #include <debug.h>
 #include <threading/rwlock.h>
@@ -230,6 +229,31 @@ METHOD(ipsec_policy_mgr_t, flush_policies, status_t,
 	return SUCCESS;
 }
 
+METHOD(ipsec_policy_mgr_t, find_by_packet, ipsec_policy_t*,
+	private_ipsec_policy_mgr_t *this, ip_packet_t *packet, bool inbound)
+{
+	enumerator_t *enumerator;
+	ipsec_policy_entry_t *current;
+	ipsec_policy_t *found = NULL;
+
+	this->lock->read_lock(this->lock);
+	enumerator = this->policies->create_enumerator(this->policies);
+	while (enumerator->enumerate(enumerator, (void**)&current))
+	{
+		ipsec_policy_t *policy = current->policy;
+
+		if ((inbound == (policy->get_direction(policy) == POLICY_IN)) &&
+			 policy->match_packet(policy, packet))
+		{
+			found = policy->get_ref(policy);
+			break;
+		}
+	}
+	enumerator->destroy(enumerator);
+	this->lock->unlock(this->lock);
+	return found;
+}
+
 METHOD(ipsec_policy_mgr_t, destroy, void,
 	private_ipsec_policy_mgr_t *this)
 {
@@ -251,6 +275,7 @@ ipsec_policy_mgr_t *ipsec_policy_mgr_create()
 			.add_policy = _add_policy,
 			.del_policy = _del_policy,
 			.flush_policies = _flush_policies,
+			.find_by_packet = _find_by_packet,
 			.destroy = _destroy,
 		},
 		.policies = linked_list_create(),

src/libipsec/ipsec_policy_mgr.h

@@ -23,6 +23,9 @@
 #ifndef IPSEC_POLICY_MGR_H_
 #define IPSEC_POLICY_MGR_H_
 
+#include "ipsec_policy.h"
+#include "ip_packet.h"
+
 #include <library.h>
 #include <utils/host.h>
 #include <utils/linked_list.h>
@@ -89,6 +92,16 @@ struct ipsec_policy_mgr_t {
 	 */
 	status_t (*flush_policies)(ipsec_policy_mgr_t *this);
 
+	/**
+	 * Find the policy that matches the given IP packet best
+	 *
+	 * @param packet		IP packet to match
+	 * @param inbound		TRUE for an inbound packet
+	 * @return				reference to the policy, or NULL if none found
+	 */
+	ipsec_policy_t *(*find_by_packet)(ipsec_policy_mgr_t *this,
+									  ip_packet_t *packet, bool inbound);
+
 	/**
 	 * Destroy an ipsec_policy_mgr_t
 	 */