Generic Hash

Data Structures
struct	lws_genhash_ctx
struct	lws_genhmac_ctx

Macros
#define	LWS_GENHASH_LARGEST   64

Enumerations
enum	lws_genhash_types {   LWS_GENHASH_TYPE_UNKNOWN , LWS_GENHASH_TYPE_MD5 , LWS_GENHASH_TYPE_SHA1 , LWS_GENHASH_TYPE_SHA256 ,   LWS_GENHASH_TYPE_SHA384 , LWS_GENHASH_TYPE_SHA512 }
enum	lws_genhmac_types { LWS_GENHMAC_TYPE_UNKNOWN , LWS_GENHMAC_TYPE_SHA256 , LWS_GENHMAC_TYPE_SHA384 , LWS_GENHMAC_TYPE_SHA512 }

Functions
LWS_VISIBLE LWS_EXTERN size_t LWS_WARN_UNUSED_RESULT	lws_genhash_size (enum lws_genhash_types type)
LWS_VISIBLE LWS_EXTERN size_t LWS_WARN_UNUSED_RESULT	lws_genhmac_size (enum lws_genhmac_types type)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_genhash_init (struct lws_genhash_ctx *ctx, enum lws_genhash_types type)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_genhash_update (struct lws_genhash_ctx *ctx, const void *in, size_t len)
LWS_VISIBLE LWS_EXTERN int	lws_genhash_destroy (struct lws_genhash_ctx *ctx, void *result)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_genhmac_init (struct lws_genhmac_ctx *ctx, enum lws_genhmac_types type, const uint8_t *key, size_t key_len)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_genhmac_update (struct lws_genhmac_ctx *ctx, const void *in, size_t len)
LWS_VISIBLE LWS_EXTERN int	lws_genhmac_destroy (struct lws_genhmac_ctx *ctx, void *result)

Detailed Description

Generic Hash related functions

Lws provides generic hash / digest accessors that abstract the ones provided by whatever tls library you are linking against.

It lets you use the same code if you build against mbedtls or OpenSSL for example.

Function Documentation

lws_genhash_destroy()

LWS_VISIBLE LWS_EXTERN int lws_genhash_destroy	(	struct lws_genhash_ctx *	ctx,
		void *	result
	)

#include <include/libwebsockets/lws-genhash.h>

lws_genhash_destroy() - copy out the result digest and destroy the ctx

Parameters

ctx	your struct lws_genhash_ctx
result	NULL, or where to copy the result hash

Finalizes the hash and copies out the digest. Destroys any allocations such that ctx can safely go out of scope after calling this.

NULL result is supported so that you can destroy the ctx cleanly on error conditions, where there is no valid result.

lws_genhash_init()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_genhash_init	(	struct lws_genhash_ctx *	ctx,
		enum lws_genhash_types	type
	)

#include <include/libwebsockets/lws-genhash.h>

lws_genhash_init() - prepare your struct lws_genhash_ctx for use

Parameters

ctx	your struct lws_genhash_ctx
type	one of LWS_GENHASH_TYPE_...

Initializes the hash context for the type you requested

lws_genhash_size()

LWS_VISIBLE LWS_EXTERN size_t LWS_WARN_UNUSED_RESULT lws_genhash_size

(

enum lws_genhash_types

type

)

#include <include/libwebsockets/lws-genhash.h>

lws_genhash_size() - get hash size in bytes

Parameters

type	one of LWS_GENHASH_TYPE_...

Returns number of bytes in this type of hash, if the hash type is unknown, it will return 0.

lws_genhash_update()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_genhash_update	(	struct lws_genhash_ctx *	ctx,
		const void *	in,
		size_t	len
	)

#include <include/libwebsockets/lws-genhash.h>

lws_genhash_update() - digest len bytes of the buffer starting at in

Parameters

ctx	your struct lws_genhash_ctx
in	start of the bytes to digest
len	count of bytes to digest

Updates the state of your hash context to reflect digesting len bytes from in

lws_genhmac_destroy()

LWS_VISIBLE LWS_EXTERN int lws_genhmac_destroy	(	struct lws_genhmac_ctx *	ctx,
		void *	result
	)

#include <include/libwebsockets/lws-genhash.h>

lws_genhmac_destroy() - copy out the result digest and destroy the ctx

Parameters

ctx	your struct lws_genhmac_ctx
result	NULL, or where to copy the result hash

Finalizes the hash and copies out the digest. Destroys any allocations such that ctx can safely go out of scope after calling this.

NULL result is supported so that you can destroy the ctx cleanly on error conditions, where there is no valid result.

lws_genhmac_init()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_genhmac_init	(	struct lws_genhmac_ctx *	ctx,
		enum lws_genhmac_types	type,
		const uint8_t *	key,
		size_t	key_len
	)

#include <include/libwebsockets/lws-genhash.h>

lws_genhmac_init() - prepare your struct lws_genhmac_ctx for use

Parameters

ctx	your struct lws_genhmac_ctx
type	one of LWS_GENHMAC_TYPE_...
key	pointer to the start of the HMAC key
key_len	length of the HMAC key

Initializes the hash context for the type you requested

If the return is nonzero, it failed and there is nothing needing to be destroyed.

lws_genhmac_size()

LWS_VISIBLE LWS_EXTERN size_t LWS_WARN_UNUSED_RESULT lws_genhmac_size

(

enum lws_genhmac_types

type

)

#include <include/libwebsockets/lws-genhash.h>

lws_genhmac_size() - get hash size in bytes

Parameters

type	one of LWS_GENHASH_TYPE_...

Returns number of bytes in this type of hmac, if the hmac type is unknown, it will return 0.

lws_genhmac_update()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_genhmac_update	(	struct lws_genhmac_ctx *	ctx,
		const void *	in,
		size_t	len
	)

#include <include/libwebsockets/lws-genhash.h>

lws_genhmac_update() - digest len bytes of the buffer starting at in

Parameters

ctx	your struct lws_genhmac_ctx
in	start of the bytes to digest
len	count of bytes to digest

Updates the state of your hash context to reflect digesting len bytes from in

If the return is nonzero, it failed and needs destroying.