backoff_algorithm.c File Reference

Implementation of the backoff algorithm API for a "Full Jitter" exponential backoff with jitter strategy. More...

#include <assert.h>
#include <stddef.h>
#include "backoff_algorithm.h"

Functions
BackoffAlgorithmStatus_t	BackoffAlgorithm_GetNextBackoff (BackoffAlgorithmContext_t *pRetryContext, uint32_t randomValue, uint16_t *pNextBackOff)
	Simple exponential backoff and jitter function that provides the delay value for the next retry attempt. After a failure of an operation that needs to be retried, the application should use this function to obtain the backoff delay value for the next retry, and then wait for the backoff time period before retrying the operation.
void	BackoffAlgorithm_InitializeParams (BackoffAlgorithmContext_t *pContext, uint16_t backOffBase, uint16_t maxBackOff, uint32_t maxAttempts)
	Initializes the context for using backoff algorithm. The parameters are required for calculating the next retry backoff delay. This function must be called by the application before the first new retry attempt.

Detailed Description

Implementation of the backoff algorithm API for a "Full Jitter" exponential backoff with jitter strategy.

Function Documentation

BackoffAlgorithm_GetNextBackoff()

BackoffAlgorithmStatus_t BackoffAlgorithm_GetNextBackoff	(	BackoffAlgorithmContext_t *	pRetryContext,
		uint32_t	randomValue,
		uint16_t *	pNextBackOff
	)

Simple exponential backoff and jitter function that provides the delay value for the next retry attempt. After a failure of an operation that needs to be retried, the application should use this function to obtain the backoff delay value for the next retry, and then wait for the backoff time period before retrying the operation.

Parameters

[in,out]	pRetryContext	Structure containing parameters for the next backoff value calculation.
[in]	randomValue	The random value to use for calculation of the backoff period. The random value should be in the range of [0, UINT32_MAX].
[out]	pNextBackOff	This will be populated with the backoff value (in milliseconds) for the next retry attempt. The value does not exceed the maximum backoff delay configured in the context.

Note

For generating a random number, it is recommended to use a Random Number Generator that is seeded with a device-specific entropy source so that possibility of collisions between multiple devices retrying the network operations can be mitigated.

Returns

BackoffAlgorithmSuccess after a successful sleep; BackoffAlgorithmRetriesExhausted when all attempts are exhausted.

BackoffAlgorithm_InitializeParams()

void BackoffAlgorithm_InitializeParams	(	BackoffAlgorithmContext_t *	pContext,
		uint16_t	backOffBase,
		uint16_t	maxBackOff,
		uint32_t	maxAttempts
	)

Initializes the context for using backoff algorithm. The parameters are required for calculating the next retry backoff delay. This function must be called by the application before the first new retry attempt.

Parameters

[out]	pContext	The context to initialize with parameters required for the next backoff delay calculation function.
[in]	maxBackOff	The maximum backoff delay (in milliseconds) between consecutive retry attempts.
[in]	backOffBase	The base value (in milliseconds) of backoff delay to use in the exponential backoff and jitter model.
[in]	maxAttempts	The maximum number of retry attempts. Set the value to BACKOFF_ALGORITHM_RETRY_FOREVER to retry for ever.