src/libipsec/esp_context.h

   1 /*
   2  * Copyright (C) 2012 Tobias Brunner
   3  * Copyright (C) 2012 Giuliano Grassi
   4  * Copyright (C) 2012 Ralf Sager
   5  * Hochschule fuer Technik Rapperswil
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2 of the License, or (at your
  10  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * for more details.
  16  */
  17
  18 /**
  19  * @defgroup esp_context esp_context
  20  * @{ @ingroup libipsec
  21  */
  22
  23 #ifndef ESP_CONTEXT_H_
  24 #define ESP_CONTEXT_H_
  25
  26 #include <library.h>
  27 #include <crypto/crypters/crypter.h>
  28 #include <crypto/signers/signer.h>
  29
  30 typedef struct esp_context_t esp_context_t;
  31
  32 /**
  33  *  ESP context, handles sequence numbers and maintains cryptographic primitives
  34  */
  35 struct esp_context_t {
  36
  37         /**
  38          * Get the crypter.
  39          *
  40          * @return                              crypter
  41          */
  42         crypter_t *(*get_crypter)(esp_context_t *this);
  43
  44         /**
  45          * Get the signer.
  46          *
  47          * @return                              signer
  48          */
  49         signer_t *(*get_signer)(esp_context_t *this);
  50
  51         /**
  52          * Get the current outbound ESP sequence number or the highest authenticated
  53          * inbound sequence number.
  54          *
  55          * @return                      current sequence number, in host byte order
  56          */
  57         u_int32_t (*get_seqno)(esp_context_t *this);
  58
  59         /**
  60          * Allocate the next outbound ESP sequence number.
  61          *
  62          * @param seqno         the sequence number, in host byte order
  63          * @return                      FALSE if the sequence number cycled or inbound context
  64          */
  65         bool (*next_seqno)(esp_context_t *this, u_int32_t *seqno);
  66
  67         /**
  68          * Verify an ESP sequence number.  Checks whether a packet with this
  69          * sequence number was already received, using the anti-replay window.
  70          * This operation does not modify the internal state.  After the sequence
  71          * number is successfully verified and the ESP packet is authenticated,
  72          * set_authenticated_seqno() should be called.
  73          *
  74          * @param seqno         the sequence number to verify, in host byte order
  75          * @return                      TRUE when sequence number is valid
  76          */
  77         bool (*verify_seqno)(esp_context_t *this, u_int32_t seqno);
  78
  79         /**
  80          * Adds a sequence number that was successfully verified and
  81          * authenticated.  A user MUST call verify_seqno() immediately before
  82          * calling this method.
  83          *
  84          * @param seqno         verified and authenticated seq number in host byte order
  85          */
  86         void (*set_authenticated_seqno)(esp_context_t *this,
  87                                                                         u_int32_t seqno);
  88
  89         /**
  90          * Destroy an esp_context_t
  91          */
  92         void (*destroy)(esp_context_t *this);
  93
  94 };
  95
  96 /**
  97  * Create an esp_context_t instance
  98  *
  99  * @param enc_alg               encryption algorithm
 100  * @param enc_key               encryption key
 101  * @param int_alg               integrity protection algorithm
 102  * @param int_key               integrity protection key
 103  * @param inbound               TRUE to create an inbound ESP context
 104  * @return                              ESP context instance, or NULL if creation fails
 105  */
 106 esp_context_t *esp_context_create(int enc_alg, chunk_t enc_key, int int_alg,
 107                                                                   chunk_t int_key, bool inbound);
 108
 109 #endif /** ESP_CONTEXT_H_ @}*/
 110