Added an option to specify the type of a policy to kernel_ipsec.add_policy.

This will later allow us to support pluto's passthrough and drop
policies in charon.

src/libhydra/kernel/kernel_interface.h

@@ -183,6 +183,7 @@ struct kernel_interface_t {
 	 * @param src_ts		traffic selector to match traffic source
 	 * @param dst_ts		traffic selector to match traffic dest
 	 * @param direction		direction of traffic, POLICY_(IN|OUT|FWD)
+	 * @param type			type of policy, POLICY_(IPSEC|PASS|DROP)
 	 * @param spi			SPI of optional ESP SA
 	 * @param ah_spi		SPI of optional AH SA
 	 * @param reqid			unique ID of an SA to use to enforce policy
@@ -197,8 +198,8 @@ struct kernel_interface_t {
 							host_t *src, host_t *dst,
 							traffic_selector_t *src_ts,
 							traffic_selector_t *dst_ts,
-							policy_dir_t direction, u_int32_t spi,
-							u_int32_t ah_spi, u_int32_t reqid,
+							policy_dir_t direction, policy_type_t type,
+							u_int32_t spi, u_int32_t ah_spi, u_int32_t reqid,
 							mark_t mark, ipsec_mode_t mode, u_int16_t ipcomp,
 							u_int16_t cpi, bool routed);