1 files changed, 148 insertions, 0 deletions
diff --git a/src/libipsec/esp_packet.h b/src/libipsec/esp_packet.h
new file mode 100644
index 000000000..473eeb4e5
--- /dev/null
+++ b/src/libipsec/esp_packet.h
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Copyright (C) 2012 Giuliano Grassi
+ * Copyright (C) 2012 Ralf Sager
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup esp_packet esp_packet
+ * @{ @ingroup libipsec
+ */
+
+#ifndef ESP_PACKET_H_
+#define ESP_PACKET_H_
+
+#include "esp_context.h"
+
+#include <library.h>
+#include <utils/host.h>
+
+typedef struct esp_packet_t esp_packet_t;
+
+/**
+ *  ESP packet
+ */
+struct esp_packet_t {
+
+	/**
+	 * Get the source address of this packet
+	 *
+	 * @return				source host
+	 */
+	host_t *(*get_source)(esp_packet_t *this);
+
+	/**
+	 * Get the destination address of this packet
+	 *
+	 * @return				destination host
+	 */
+	host_t *(*get_destination)(esp_packet_t *this);
+
+	/**
+	 * Parse the packet header before decryption. Tries to read the SPI
+	 * from the packet to find a corresponding SA.
+	 *
+	 * @param spi			parsed SPI, in network byte order
+	 * @return				TRUE when successful, FALSE otherwise (e.g. when the
+	 *						length of the packet is invalid)
+	 */
+	bool (*parse_header)(esp_packet_t *this, u_int32_t *spi);
+
+	/**
+	 * Authenticate and decrypt the packet. Also verifies the sequence number
+	 * using the supplied ESP context and updates the anti-replay window.
+	 *
+	 * @param esp_context		ESP context of corresponding inbound IPsec SA
+	 * @return					- SUCCESS if successfully authenticated,
+	 *							  decrypted and parsed
+	 *							- PARSE_ERROR if the length of the packet or the
+	 *							  padding is invalid
+	 *							- VERIFY_ERROR if the sequence number
+	 *							  verification failed
+	 *							- FAILED if the ICV (MAC) check or the actual
+	 *							  decryption failed
+	 */
+	status_t (*decrypt)(esp_packet_t *this, esp_context_t *esp_context);
+
+	/**
+	 * Encapsulate and encrypt the packet. The sequence number will be generated
+	 * using the supplied ESP context.
+	 *
+	 * @param esp_context		ESP context of corresponding outbound IPsec SA
+	 * @param spi				SPI value to use, in network byte order
+	 * @return					- SUCCESS if encrypted
+	 *							- FAILED if sequence number cycled or any of the
+	 *							  cryptographic functions failed
+	 *							- NOT_FOUND if no suitable RNG could be found
+	 */
+	status_t (*encrypt)(esp_packet_t *this, esp_context_t *esp_context,
+						u_int32_t spi);
+
+	/**
+	 * Get the next header field of a packet.
+	 *
+	 * @note Packet has to be in the decrypted state.
+	 *
+	 * @return					next header field
+	 */
+	u_int8_t (*get_next_header)(esp_packet_t *this);
+
+	/**
+	 * Get the plaintext payload of this packet (e.g. inner IP packet).
+	 *
+	 * @return					plaintext payload (internal data),
+	 * 							chunk_empty if not decrypted
+	 */
+	chunk_t (*get_payload)(esp_packet_t *this);
+
+	/**
+	 * Get the packet data to send / as received on the wire.
+	 *
+	 * @return					encrypted packet data (internal data),
+	 * 							chunk_empty if not encrypted
+	 */
+	chunk_t (*get_packet_data)(esp_packet_t *this);
+
+	/**
+	 * Destroy an esp_packet_t
+	 */
+	void (*destroy)(esp_packet_t *this);
+
+};
+
+/**
+ * Create an ESP packet out of data from the wire.
+ *
+ * @param src			source address from which the packet was sent, owned
+ * @param dst			destination address to which the packet was sent, owned
+ * @param data			the packet data as received, gets owned
+ * @return				esp_packet_t instance
+ */
+esp_packet_t *esp_packet_create_from_packet(host_t *src, host_t *dst,
+											chunk_t data);
+
+/**
+ * Create an ESP packet from a plaintext payload (e.g. inner IP packet)
+ *
+ * @param src			source address
+ * @param dst			destination address
+ * @param payload		plaintext payload (e.g. inner IP packet), gets owned
+ * @param next_header	next header type of the payload (e.g IPPROTO_IPIP)
+ * @return				esp_packet_t instance
+ */
+esp_packet_t *esp_packet_create_from_payload(host_t *src, host_t *dst,
+										chunk_t payload, u_int8_t next_header);
+
+#endif /** ESP_PACKET_H_ @}*/
+