kernel-interface: Remove reqid parameter from get_spi/get_cpi() methods

The reqid is not strictly required, as we set the reqid with the update
call when installing the negotiated SA.

If we don't need a reqid at this stage, we can later allocate the reqid in
the kernel backend once the SA parameters have been fully negotaited. This
allows us to assign the same reqid for the same selectors to avoid conflicts
on backends this is necessary.

src/libhydra/kernel/kernel_ipsec.h

@@ -58,24 +58,22 @@ struct kernel_ipsec_t {
 	 * @param src		source address of SA
 	 * @param dst		destination address of SA
 	 * @param protocol	protocol for SA (ESP/AH)
-	 * @param reqid		unique ID for this SA
 	 * @param spi		allocated spi
-	 * @return				SUCCESS if operation completed
+	 * @return			SUCCESS if operation completed
 	 */
 	status_t (*get_spi)(kernel_ipsec_t *this, host_t *src, host_t *dst,
-						u_int8_t protocol, u_int32_t reqid, u_int32_t *spi);
+						u_int8_t protocol, u_int32_t *spi);
 
 	/**
 	 * Get a Compression Parameter Index (CPI) from the kernel.
 	 *
 	 * @param src		source address of SA
 	 * @param dst		destination address of SA
-	 * @param reqid		unique ID for the corresponding SA
 	 * @param cpi		allocated cpi
-	 * @return				SUCCESS if operation completed
+	 * @return			SUCCESS if operation completed
 	 */
 	status_t (*get_cpi)(kernel_ipsec_t *this, host_t *src, host_t *dst,
-						u_int32_t reqid, u_int16_t *cpi);
+						u_int16_t *cpi);
 
 	/**
 	 * Add an SA to the SAD.