Added Static Buffer Allocation API

Author: jackctj117

doc/dox_comments/header_files/memory.h

@@ -217,3 +217,195 @@ int wolfSSL_StaticBufferSz(byte* buffer, word32 sz, int flag);
     \sa wolfSSL_Free
 */
 int wolfSSL_MemoryPaddingSz(void);
+
+/*!
+    \ingroup Memory
+
+    \brief This function is used to set aside static memory for a CTX.
+    Memory set aside is then used for the CTX’s lifetime and for any SSL objects created
+    from the CTX. By passing in a NULL ctx pointer and a wolfSSL_method_func function the creation
+    of the CTX itself will also use static memory. wolfSSL_method_func has the function signature
+    of WOLFSSL_METHOD* (*wolfSSL_method_func)(void* heap);.
+    Passing in 0 for max makes it behave as if not set and no max concurrent use restrictions
+    is in place.
+    The flag value passed in determines how the memory is used and behavior while operating.
+    Available flags are the following.
+
+    0 - default general memory
+
+    WOLFMEM_IO_POOL - used for input/output buffer when sending receiving messages.
+    Overrides general memory, so all memory in buffer passed in is used for IO.
+    WOLFMEM_IO_FIXED - same as WOLFMEM_IO_POOL but each SSL now keeps two
+    buffers to themselves for their lifetime.
+    WOLFMEM_TRACK_STATS - each SSL keeps track of memory stats while running.
+
+    \return If successful, SSL_SUCCESS will be returned.
+    \return All unsuccessful return values will be less than 0 or equal to SSL_FAILURE.
+
+    \param ctx address of pointer to a WOLFSSL_CTX structure.
+    \param method function to create protocol. (should be NULL if ctx is not also NULL)
+    \param buf memory to use for all operations.
+    \param sz size of memory buffer being passed in.
+    \param flag type of memory.
+    \param max max concurrent operations.
+
+    _Example_
+    \code
+    WOLFSSL_CTX* ctx;
+    WOLFSSL* ssl;
+    int ret;
+    unsigned char memory[MAX];
+    int memorySz = MAX;
+    unsigned char IO[MAX];
+    int IOSz = MAX;
+    int flag = WOLFMEM_IO_FIXED | WOLFMEM_TRACK_STATS;
+    ...
+    // create ctx also using static memory, start with general memory to use
+    ctx = NULL:
+    ret = wolfSSL_CTX_load_static_memory(&ctx, wolfSSLv23_server_method_ex, memory, memorySz, 0,
+    MAX_CONCURRENT_HANDSHAKES);
+    if (ret != SSL_SUCCESS) {
+    // handle error case
+    }
+    // load in memory for use with IO
+    ret = wolfSSL_CTX_load_static_memory(&ctx, NULL, IO, IOSz, flag, MAX_CONCURRENT_IO);
+    if (ret != SSL_SUCCESS) {
+    // handle error case
+    }
+    ...
+    \endcode
+
+    \sa wolfSSL_CTX_new
+    \sa wolfSSL_CTX_is_static_memory
+    \sa wolfSSL_is_static_memory
+*/
+int wolfSSL_CTX_load_static_memory(WOLFSSL_CTX** ctx, wolfSSL_method_func method,
+        unsigned char* buf, unsigned int sz, int flag, int max);
+
+/*!
+    \ingroup Memory
+
+    \brief This function does not change any of the connections behavior and is used only for
+    gathering information about the static memory usage.
+
+    \return A value of 1 is returned if using static memory for the CTX is true.
+    \return 0 is returned if not using static memory.
+
+    \param ctx a pointer to a WOLFSSL_CTX structure, created using wolfSSL_CTX_new().
+    \param mem_stats structure to hold information about staic memory usage.
+
+    _Example_
+    \code
+    WOLFSSL_CTX* ctx;
+    int ret;
+    WOLFSSL_MEM_STATS mem_stats;
+    ...
+    //get information about static memory with CTX
+
+    ret = wolfSSL_CTX_is_static_memory(ctx, &mem_stats);
+
+    if (ret == 1) {
+        // handle case of is using static memory
+        // print out or inspect elements of mem_stats
+    }
+
+    if (ret == 0) {
+        //handle case of ctx not using static memory
+    }
+    ...
+    \endcode
+
+    \sa wolfSSL_CTX_new
+    \sa wolfSSL_CTX_load_static_memory
+    \sa wolfSSL_is_static_memory
+*/
+int wolfSSL_CTX_is_static_memory(WOLFSSL_CTX* ctx, WOLFSSL_MEM_STATS* mem_stats);
+
+/*!
+    \ingroup Memory
+
+    \brief wolfSSL_is_static_memory is used to gather information about a SSL’s static
+    memory usage. The return value indicates if static memory is being used and
+    WOLFSSL_MEM_CONN_STATS will be filled out if and only if the flag WOLFMEM_TRACK_STATS was
+    passed to the parent CTX when loading in static memory.
+
+    \return A value of 1 is returned if using static memory for the CTX is true.
+    \return 0 is returned if not using static memory.
+
+    \param ssl a pointer to a WOLFSSL structure, created using wolfSSL_new().
+    \param mem_stats structure to contain static memory usage
+
+    _Example_
+    \code
+    WOLFSSL* ssl;
+    int ret;
+    WOLFSSL_MEM_CONN_STATS mem_stats;
+
+    ...
+
+    ret = wolfSSL_is_static_memory(ssl, mem_stats);
+
+    if (ret == 1) {
+        // handle case when is static memory
+        // investigate elements in mem_stats if WOLFMEM_TRACK_STATS flag
+    }
+    ...
+    \endcode
+
+    \sa wolfSSL_new
+    \sa wolfSSL_CTX_is_static_memory
+*/
+int wolfSSL_is_static_memory(WOLFSSL* ssl, WOLFSSL_MEM_CONN_STATS* mem_stats);
+
+/*!
+    \ingroup Memory
+
+    \brief This function is used to set aside static memory for wolfCrypt use. Memory can be
+    used by passing the created heap hint into functions. An example of this is when calling
+    wc_InitRng_ex. The flag value passed in determines how the memory is used and behavior
+    while operating, in general wolfCrypt operations will use memory from a WOLFMEM_GENERAL pool.
+    Available flags are the following.
+
+    WOLFMEM_GENERAL - default general memory
+
+    WOLFMEM_IO_POOL - used for input/output buffer when sending receiving messages.
+        Overrides general memory, so all memory in buffer passed in is used for IO.
+    WOLFMEM_IO_FIXED - same as WOLFMEM_IO_POOL but each SSL now keeps two
+        buffers to themselves for their lifetime.
+    WOLFMEM_TRACK_STATS - each SSL keeps track of memory stats while running
+
+    \return If successful, 0 will be returned.
+    \return All unsuccessful return values will be less than 0.
+
+    \param hint WOLFSSL_HEAP_HINT structure to use
+    \param buf memory to use for all operations.
+    \param sz size of memory buffer being passed in.
+    \param flag type of memory.
+    \param max max concurrent operations (handshakes, IO).
+
+    _Example_
+    \code
+    WOLFSSL_HEAP_HINT hint;
+    int ret;
+    unsigned char memory[MAX];
+    int memorySz = MAX;
+    int flag = WOLFMEM_GENERAL | WOLFMEM_TRACK_STATS;
+    ...
+
+    // load in memory for use
+
+    ret = wc_LoadStaticMemory(&hint, memory, memorySz, flag, 0);
+    if (ret != SSL_SUCCESS) {
+        // handle error case
+    }
+    ...
+
+    ret = wc_InitRng_ex(&rng, hint, 0);
+
+    // check ret value
+    \endcode
+
+    \sa none
+*/
+int wc_LoadStaticMemory(WOLFSSL_HEAP_HINT* hint, unsigned char* buf, unsigned int sz,
+                int flag, int max);