add srtp

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@1086 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/srtp/crypto/include/xfm.h

@@ -0,0 +1,139 @@
+/*
+ * xfm.h
+ *
+ * interface for abstract crypto transform
+ * 
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+#ifndef XFM_H
+#define XFM_H
+
+#include "crypto_kernel.h"
+#include "err.h"
+
+/**
+ * @defgroup Crypto Cryptography
+ *
+ * A simple interface to an abstract cryptographic transform that
+ * provides both confidentiality and message authentication.
+ *
+ * @{
+ */
+
+/**
+ * @brief applies a crypto transform
+ *
+ * The function pointer xfm_func_t points to a function that
+ * implements a crypto transform, and provides a uniform API for
+ * accessing crypto mechanisms.
+ * 
+ * @param key       location of secret key                  
+ *
+ * @param clear     data to be authenticated only           
+ *
+ * @param clear_len length of data to be authenticated only 
+ *
+ * @param iv        location to write the Initialization Vector (IV)
+ *
+ * @param protect   location of the data to be encrypted and
+ * authenticated (before the function call), and the ciphertext
+ * and authentication tag (after the call)
+ *
+ * @param protected_len location of the length of the data to be
+ * encrypted and authenticated (before the function call), and the
+ * length of the ciphertext (after the call)
+ *
+ * @param auth_tag   location to write auth tag              
+ */
+
+typedef err_status_t (*xfm_func_t) 
+     (void *key,            
+      void *clear,          
+      unsigned clear_len,   
+      void *iv,             
+      void *protect,         
+      unsigned *protected_len, 
+      void *auth_tag        
+      );
+
+typedef 
+err_status_t (*xfm_inv_t)
+     (void *key,            /* location of secret key                  */
+      void *clear,          /* data to be authenticated only           */
+      unsigned clear_len,   /* length of data to be authenticated only */
+      void *iv,             /* location of iv                          */
+      void *opaque,         /* data to be decrypted and authenticated  */
+      unsigned *opaque_len, /* location of the length of data to be
+			     * decrypted and authd (before and after) 
+			     */
+      void *auth_tag        /* location of auth tag                    */
+      );
+
+typedef struct xfm_ctx_t {
+  xfm_func_t func;
+  xfm_inv_t  inv;
+  unsigned key_len;
+  unsigned iv_len;
+  unsigned auth_tag_len;
+} xfm_ctx_t;
+
+typedef xfm_ctx_t *xfm_t;
+
+#define xfm_get_key_len(xfm) ((xfm)->key_len)
+
+#define xfm_get_iv_len(xfm) ((xfm)->iv_len)
+
+#define xfm_get_auth_tag_len(xfm) ((xfm)->auth_tag_len)
+
+
+/* cryptoalgo - 5/28 */
+  
+typedef err_status_t (*cryptoalg_func_t) 
+     (void *key,            
+      void *clear,          
+      unsigned clear_len,   
+      void *iv,             
+      void *opaque,         
+      unsigned *opaque_len
+      );
+
+typedef 
+err_status_t (*cryptoalg_inv_t)
+     (void *key,            /* location of secret key                  */
+      void *clear,          /* data to be authenticated only           */
+      unsigned clear_len,   /* length of data to be authenticated only */
+      void *iv,             /* location of iv                          */
+      void *opaque,         /* data to be decrypted and authenticated  */
+      unsigned *opaque_len  /* location of the length of data to be
+			     * decrypted and authd (before and after) 
+			     */
+      );
+
+typedef struct cryptoalg_ctx_t {
+  cryptoalg_func_t enc;
+  cryptoalg_inv_t  dec;
+  unsigned key_len;
+  unsigned iv_len;
+  unsigned auth_tag_len;
+  unsigned max_expansion; 
+} cryptoalg_ctx_t;
+
+typedef cryptoalg_ctx_t *cryptoalg_t;
+
+#define cryptoalg_get_key_len(cryptoalg) ((cryptoalg)->key_len)
+
+#define cryptoalg_get_iv_len(cryptoalg) ((cryptoalg)->iv_len)
+
+#define cryptoalg_get_auth_tag_len(cryptoalg) ((cryptoalg)->auth_tag_len)
+
+
+
+/**
+ * @}
+ */
+
+#endif /* XFM_H */
+
+