Enhance GCM throughput using larger precalculated tables. Also refactored the code for shorter tables and moved the check for available accelerators to the context initialization code.
Signed-off-by: Matthias Schulz <mschulz@hilscher.com>
diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 631b392..f475710 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -33,6 +33,11 @@
#define MBEDTLS_GCM_ENCRYPT 1
#define MBEDTLS_GCM_DECRYPT 0
+#define MBEDTLS_GCM_ACC_SMALLTABLE 0
+#define MBEDTLS_GCM_ACC_LARGETABLE 1
+#define MBEDTLS_GCM_ACC_AESNI 2
+#define MBEDTLS_GCM_ACC_AESCE 3
+
/** Authenticated decryption failed. */
#define MBEDTLS_ERR_GCM_AUTH_FAILED -0x0012
/** Bad input parameters to function. */
@@ -46,6 +51,12 @@
#if !defined(MBEDTLS_GCM_ALT)
+#if defined(MBEDTLS_GCM_LARGETABLE)
+#define MBEDTLS_GCM_HTABLE_SIZE 256
+#else
+#define MBEDTLS_GCM_HTABLE_SIZE 16
+#endif
+
/**
* \brief The GCM context structure.
*/
@@ -53,18 +64,22 @@
#if defined(MBEDTLS_BLOCK_CIPHER_C)
mbedtls_block_cipher_context_t MBEDTLS_PRIVATE(block_cipher_ctx); /*!< The cipher context used. */
#else
- mbedtls_cipher_context_t MBEDTLS_PRIVATE(cipher_ctx); /*!< The cipher context used. */
+ mbedtls_cipher_context_t MBEDTLS_PRIVATE(cipher_ctx); /*!< The cipher context used. */
#endif
- uint64_t MBEDTLS_PRIVATE(HL)[16]; /*!< Precalculated HTable low. */
- uint64_t MBEDTLS_PRIVATE(HH)[16]; /*!< Precalculated HTable high. */
- uint64_t MBEDTLS_PRIVATE(len); /*!< The total length of the encrypted data. */
- uint64_t MBEDTLS_PRIVATE(add_len); /*!< The total length of the additional data. */
- unsigned char MBEDTLS_PRIVATE(base_ectr)[16]; /*!< The first ECTR for tag. */
- unsigned char MBEDTLS_PRIVATE(y)[16]; /*!< The Y working value. */
- unsigned char MBEDTLS_PRIVATE(buf)[16]; /*!< The buf working value. */
- int MBEDTLS_PRIVATE(mode); /*!< The operation to perform:
- #MBEDTLS_GCM_ENCRYPT or
- #MBEDTLS_GCM_DECRYPT. */
+ uint64_t MBEDTLS_PRIVATE(H)[MBEDTLS_GCM_HTABLE_SIZE][2]; /*!< Precalculated HTable. */
+ uint64_t MBEDTLS_PRIVATE(len); /*!< The total length of the encrypted data. */
+ uint64_t MBEDTLS_PRIVATE(add_len); /*!< The total length of the additional data. */
+ unsigned char MBEDTLS_PRIVATE(base_ectr)[16]; /*!< The first ECTR for tag. */
+ unsigned char MBEDTLS_PRIVATE(y)[16]; /*!< The Y working value. */
+ unsigned char MBEDTLS_PRIVATE(buf)[16]; /*!< The buf working value. */
+ unsigned char MBEDTLS_PRIVATE(mode); /*!< The operation to perform:
+ #MBEDTLS_GCM_ENCRYPT or
+ #MBEDTLS_GCM_DECRYPT. */
+ unsigned char MBEDTLS_PRIVATE(acceleration); /*!< The acceleration to use:
+ #MBEDTLS_GCM_ACC_SMALLTABLE,
+ #MBEDTLS_GCM_ACC_LARGETABLE,
+ #MBEDTLS_GCM_ACC_AESNI,
+ #MBEDTLS_GCM_ACC_AESCE */
}
mbedtls_gcm_context;
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 6a5828c..f467737 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -2801,6 +2801,20 @@
#define MBEDTLS_GCM_C
/**
+ * \def MBEDTLS_GCM_LARGETABLE
+ *
+ * Enable large precomputer tables for Galois/Counter Mode (GCM).
+ * Can significantly increase throughput on systems without GCM hardware
+ * acceleration (e.g., AESNI, AESCE).
+ *
+ * Module: library/gcm.c
+ *
+ * Requires: MBEDTLS_GCM_C
+ *
+ */
+//#define MBEDTLS_GCM_LARGETABLE
+
+/**
* \def MBEDTLS_HKDF_C
*
* Enable the HKDF algorithm (RFC 5869).