Diff: iothub_client_retry_control.c

Revision:

25:a35763780a87

Child:

36:3b9944257dd5

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/iothub_client_retry_control.c	Fri Jul 28 09:52:04 2017 -0700
@@ -0,0 +1,552 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+#include "iothub_client_retry_control.h"
+
+#include <math.h>
+
+#include "azure_c_shared_utility/gballoc.h"
+#include "azure_c_shared_utility/agenttime.h"
+#include "azure_c_shared_utility/optimize_size.h"
+#include "azure_c_shared_utility/xlogging.h"
+
+#define RESULT_OK           0
+#define INDEFINITE_TIME     ((time_t)-1)
+
+typedef struct RETRY_CONTROL_INSTANCE_TAG
+{
+	IOTHUB_CLIENT_RETRY_POLICY policy;
+	unsigned int max_retry_time_in_secs;
+
+	unsigned int initial_wait_time_in_secs;
+	unsigned int max_jitter_percent;
+
+	unsigned int retry_count;
+	time_t first_retry_time;
+	time_t last_retry_time;
+	unsigned int current_wait_time_in_secs;
+} RETRY_CONTROL_INSTANCE;
+
+typedef int (*RETRY_ACTION_EVALUATION_FUNCTION)(RETRY_CONTROL_INSTANCE* retry_state, RETRY_ACTION* retry_action);
+
+
+// ========== Helper Functions ========== //
+
+static int evaluate_retry_action_fixed_interval(RETRY_CONTROL_INSTANCE* retry_control, RETRY_ACTION* retry_action)
+{
+	int result;
+
+	time_t current_time;
+
+	if ((current_time = get_time(NULL)) == INDEFINITE_TIME)
+	{
+		LogError("Cannot evaluate if should retry (get_time failed)");
+		result = __FAILURE__;
+	}
+	else
+	{
+		if (retry_control->max_retry_time_in_secs > 0 &&
+			get_difftime(current_time, retry_control->last_retry_time) >= retry_control->max_retry_time_in_secs)
+		{
+			*retry_action = RETRY_ACTION_STOP_RETRYING;
+		}
+		else
+		{
+			if (get_difftime(current_time, retry_control->last_retry_time) >= retry_control->current_wait_time_in_secs)
+			{
+				*retry_action = RETRY_ACTION_RETRY_NOW;
+				retry_control->last_retry_time = current_time;
+			}
+			else
+			{
+				*retry_action = RETRY_ACTION_RETRY_LATER;
+			}
+		}
+
+		result = RESULT_OK;
+	}
+
+	return result;
+}
+
+
+// ---------- Set/Retrieve Options Helpers ----------//
+
+static void* retry_control_clone_option(const char* name, const void* value)
+{
+	void* result;
+
+	if ((name == NULL) || (value == NULL))
+	{
+		LogError("Failed to clone option (either name (%p) or value (%p) are NULL)", name, value);
+		result = NULL;
+	}
+	else if (strcmp(RETRY_CONTROL_OPTION_INITIAL_WAIT_TIME_IN_SECS, name) == 0 ||
+			strcmp(RETRY_CONTROL_OPTION_MAX_JITTER_PERCENT, name) == 0)
+	{
+		unsigned int* cloned_value;
+
+		if ((cloned_value = (unsigned int*)malloc(sizeof(unsigned int))) == NULL)
+		{
+			LogError("Failed to clone option '%p' (malloc failed)", name);
+			result = NULL;
+		}
+		else
+		{
+			*cloned_value = *(unsigned int*)value;
+
+			result = (void*)cloned_value;
+		}
+	}
+	else
+	{
+		LogError("Failed to clone option (option with name '%s' is not suppported)", name);
+		result = NULL;
+	}
+
+	return result;
+}
+
+static void retry_control_destroy_option(const char* name, const void* value)
+{
+	if ((name == NULL) || (value == NULL))
+	{
+		LogError("Failed to destroy option (either name (%p) or value (%p) are NULL)", name, value);
+	}
+	else if (strcmp(RETRY_CONTROL_OPTION_INITIAL_WAIT_TIME_IN_SECS, name) == 0 ||
+		strcmp(RETRY_CONTROL_OPTION_MAX_JITTER_PERCENT, name) == 0)
+	{
+		free((void*)value);
+	}
+	else
+	{
+		LogError("Failed to destroy option (option with name '%s' is not suppported)", name);
+	}
+}
+
+// ========== _should_retry() Auxiliary Functions ========== //
+
+static int evaluate_retry_action(RETRY_CONTROL_INSTANCE* retry_control, RETRY_ACTION* retry_action)
+{
+	int result;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_019: [If `retry_control->retry_count` is 0, `retry_action` shall be set to RETRY_ACTION_RETRY_NOW]
+	if (retry_control->retry_count == 0)
+	{
+		*retry_action = RETRY_ACTION_RETRY_NOW;
+		result = RESULT_OK;
+	}
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_020: [If `retry_control->last_retry_time` is INDEFINITE_TIME and policy is not IOTHUB_CLIENT_RETRY_IMMEDIATE, the evaluation function shall return non-zero]
+	else if (retry_control->last_retry_time == INDEFINITE_TIME &&
+		     retry_control->policy != IOTHUB_CLIENT_RETRY_IMMEDIATE)
+	{
+		LogError("Failed to evaluate retry action (last_retry_time is INDEFINITE_TIME)");
+		result = __FAILURE__;
+	}
+	else
+	{
+		time_t current_time;
+
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_021: [`current_time` shall be set using get_time()]
+		if ((current_time = get_time(NULL)) == INDEFINITE_TIME)
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_022: [If get_time() fails, the evaluation function shall return non-zero]
+			LogError("Failed to evaluate retry action (get_time() failed)");
+			result = __FAILURE__;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_023: [If `retry_control->max_retry_time_in_secs` is not 0 and (`current_time` - `retry_control->first_retry_time`) is greater than or equal to `retry_control->max_retry_time_in_secs`, `retry_action` shall be set to RETRY_ACTION_STOP_RETRYING]
+		else if (retry_control->max_retry_time_in_secs > 0 &&
+			get_difftime(current_time, retry_control->first_retry_time) >= retry_control->max_retry_time_in_secs)
+		{
+			*retry_action = RETRY_ACTION_STOP_RETRYING;
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_026: [If no errors occur, the evaluation function shall return 0]
+			result = RESULT_OK;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_028: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_IMMEDIATE, retry_action shall be set to RETRY_ACTION_RETRY_NOW]
+		else if (retry_control->policy == IOTHUB_CLIENT_RETRY_IMMEDIATE)
+		{
+			*retry_action = RETRY_ACTION_RETRY_NOW;
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_026: [If no errors occur, the evaluation function shall return 0]
+			result = RESULT_OK;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_024: [Otherwise, if (`current_time` - `retry_control->last_retry_time`) is less than `retry_control->current_wait_time_in_secs`, `retry_action` shall be set to RETRY_ACTION_RETRY_LATER]
+		else if (get_difftime(current_time, retry_control->last_retry_time) < retry_control->current_wait_time_in_secs)
+		{
+			*retry_action = RETRY_ACTION_RETRY_LATER;
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_026: [If no errors occur, the evaluation function shall return 0]
+			result = RESULT_OK;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_025: [Otherwise, if (`current_time` - `retry_control->last_retry_time`) is greater or equal to `retry_control->current_wait_time_in_secs`, `retry_action` shall be set to RETRY_ACTION_RETRY_NOW]
+		else
+		{
+			*retry_action = RETRY_ACTION_RETRY_NOW;
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_026: [If no errors occur, the evaluation function shall return 0]
+			result = RESULT_OK;
+		}
+	}
+
+	return result;
+}
+
+static unsigned int calculate_next_wait_time(RETRY_CONTROL_INSTANCE* retry_control)
+{
+	unsigned int result;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_029: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_INTERVAL, `calculate_next_wait_time` shall return `retry_control->initial_wait_time_in_secs`]
+	if (retry_control->policy == IOTHUB_CLIENT_RETRY_INTERVAL)
+	{
+		result = retry_control->initial_wait_time_in_secs;
+	}
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_030: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_LINEAR_BACKOFF, `calculate_next_wait_time` shall return (`retry_control->initial_wait_time_in_secs` * (`retry_control->retry_count`))]
+	else if (retry_control->policy == IOTHUB_CLIENT_RETRY_LINEAR_BACKOFF)
+	{
+		result = retry_control->initial_wait_time_in_secs * (retry_control->retry_count);
+	}
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_031: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF, `calculate_next_wait_time` shall return (pow(2, `retry_control->retry_count` - 1) * `retry_control->initial_wait_time_in_secs`)]
+	else if (retry_control->policy == IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF)
+	{
+		result = (unsigned int)(pow(2, retry_control->retry_count - 1) * retry_control->initial_wait_time_in_secs);
+	}
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_032: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF_WITH_JITTER, `calculate_next_wait_time` shall return ((pow(2, `retry_control->retry_count` - 1) * `retry_control->initial_wait_time_in_secs`) * (1 + (`retry_control->max_jitter_percent` / 100) * (rand() / RAND_MAX)))]
+	else if (retry_control->policy == IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF_WITH_JITTER)
+	{
+		double jitter_percent = (retry_control->max_jitter_percent / 100.0) * (rand() / ((double)RAND_MAX));
+
+		result = (unsigned int)(pow(2, retry_control->retry_count - 1) * retry_control->initial_wait_time_in_secs * (1 + jitter_percent));
+	}
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_033: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_RANDOM, `calculate_next_wait_time` shall return (`retry_control->initial_wait_time_in_secs` * (rand() / RAND_MAX))]
+	else if (retry_control->policy == IOTHUB_CLIENT_RETRY_RANDOM)
+	{
+		double random_percent = ((double)rand() / (double)RAND_MAX);
+		result = (unsigned int)(retry_control->initial_wait_time_in_secs * random_percent);
+	}
+	else
+	{
+		LogError("Failed to calculate the next wait time (policy %d is not expected)", retry_control->policy);
+
+		result = 0;
+	}
+
+	return result;
+}
+
+
+// ========== Public API ========== //
+
+int is_timeout_reached(time_t start_time, unsigned int timeout_in_secs, bool* is_timed_out)
+{
+	int result;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_057: [If `start_time` is INDEFINITE_TIME, `is_timeout_reached` shall fail and return non-zero]
+	if (start_time == INDEFINITE_TIME)
+	{
+		LogError("Failed to verify timeout (start_time is INDEFINITE)");
+		result = __FAILURE__;
+	}
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_058: [If `is_timed_out` is NULL, `is_timeout_reached` shall fail and return non-zero]
+	else if (is_timed_out == NULL)
+	{
+		LogError("Failed to verify timeout (is_timed_out is NULL)");
+		result = __FAILURE__;
+	}
+	else
+	{
+		time_t current_time;
+
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_059: [`is_timeout_reached` shall obtain the `current_time` using get_time()]
+		if ((current_time = get_time(NULL)) == INDEFINITE_TIME)
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_060: [If get_time() fails, `is_timeout_reached` shall fail and return non-zero]
+			LogError("Failed to verify timeout (get_time failed)");
+			result = __FAILURE__;
+		}
+		else
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_061: [If (`current_time` - `start_time`) is greater or equal to `timeout_in_secs`, `is_timed_out` shall be set to true]
+			if (get_difftime(current_time, start_time) >= timeout_in_secs)
+			{
+				*is_timed_out = true;
+			}
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_062: [If (`current_time` - `start_time`) is less than `timeout_in_secs`, `is_timed_out` shall be set to false]
+			else
+			{
+				*is_timed_out = false;
+			}
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_063: [If no errors occur, `is_timeout_reached` shall return 0]
+			result = RESULT_OK;
+		}
+	}
+
+	return result;
+}
+
+void retry_control_reset(RETRY_CONTROL_HANDLE retry_control_handle)
+{
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_034: [If `retry_control_handle` is NULL, `retry_control_reset` shall return]
+	if (retry_control_handle == NULL)
+	{
+		LogError("Failed to reset the retry control (retry_state_handle is NULL)");
+	}
+	else
+	{
+		RETRY_CONTROL_INSTANCE* retry_control = (RETRY_CONTROL_INSTANCE*)retry_control_handle;
+
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_035: [`retry_control` shall have fields `retry_count` and `current_wait_time_in_secs` set to 0 (zero), `first_retry_time` and `last_retry_time` set to INDEFINITE_TIME]
+		retry_control->retry_count = 0;
+		retry_control->current_wait_time_in_secs = 0;
+		retry_control->first_retry_time = INDEFINITE_TIME;
+		retry_control->last_retry_time = INDEFINITE_TIME;
+	}
+}
+
+RETRY_CONTROL_HANDLE retry_control_create(IOTHUB_CLIENT_RETRY_POLICY policy, unsigned int max_retry_time_in_secs)
+{
+	RETRY_CONTROL_INSTANCE* retry_control;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_002: [`retry_control_create` shall allocate memory for the retry control instance structure (a.k.a. `retry_control`)]
+	if ((retry_control = (RETRY_CONTROL_INSTANCE*)malloc(sizeof(RETRY_CONTROL_INSTANCE))) == NULL)
+	{
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_003: [If malloc fails, `retry_control_create` shall fail and return NULL]
+		LogError("Failed creating the retry control (malloc failed)");
+	}
+	else
+	{
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_004: [The parameters passed to `retry_control_create` shall be saved into `retry_control`]
+		memset(retry_control, 0, sizeof(RETRY_CONTROL_INSTANCE));
+		retry_control->policy = policy;
+		retry_control->max_retry_time_in_secs = max_retry_time_in_secs;
+
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_005: [If `policy` is IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF or IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF_WITH_JITTER, `retry_control->initial_wait_time_in_secs` shall be set to 1]
+		if (retry_control->policy == IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF ||
+			retry_control->policy == IOTHUB_CLIENT_RETRY_EXPONENTIAL_BACKOFF_WITH_JITTER)
+		{
+			retry_control->initial_wait_time_in_secs = 1;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_006: [Otherwise `retry_control->initial_wait_time_in_secs` shall be set to 5]
+		else
+		{
+			retry_control->initial_wait_time_in_secs = 5;
+		}
+
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_007: [`retry_control->max_jitter_percent` shall be set to 5]
+		retry_control->max_jitter_percent = 5;
+	
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_008: [The remaining fields in `retry_control` shall be initialized according to retry_control_reset()]
+		retry_control_reset(retry_control);
+	}
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_009: [If no errors occur, `retry_control_create` shall return a handle to `retry_control`]
+	return (RETRY_CONTROL_HANDLE)retry_control;
+}
+
+void retry_control_destroy(RETRY_CONTROL_HANDLE retry_control_handle)
+{
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_055: [If `retry_control_handle` is NULL, `retry_control_destroy` shall return]
+	if (retry_control_handle == NULL)
+	{
+		LogError("Failed to destroy the retry control (retry_control_handle is NULL)");
+	}
+	else
+	{
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_056: [`retry_control_destroy` shall destroy `retry_control_handle` using free()]
+		free(retry_control_handle);
+	}
+}
+
+int retry_control_should_retry(RETRY_CONTROL_HANDLE retry_control_handle, RETRY_ACTION* retry_action)
+{
+	int result;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_010: [If `retry_control_handle` or `retry_action` are NULL, `retry_control_should_retry` shall fail and return non-zero]
+	if ((retry_control_handle == NULL) || (retry_action == NULL))
+	{
+		LogError("Failed to evaluate if retry should be attempted (either retry_control_handle (%p) or retry_action (%p) are NULL)", retry_control_handle, retry_action);
+		result = __FAILURE__;
+	}
+	else
+	{
+		RETRY_CONTROL_INSTANCE* retry_control = (RETRY_CONTROL_INSTANCE*)retry_control_handle;
+
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_027: [If `retry_control->policy` is IOTHUB_CLIENT_RETRY_NONE, retry_action shall be set to RETRY_ACTION_STOP_RETRYING and return immediatelly with result 0]
+		if (retry_control->policy == IOTHUB_CLIENT_RETRY_NONE)
+		{
+			*retry_action = RETRY_ACTION_STOP_RETRYING;
+			result = RESULT_OK;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_011: [If `retry_control->first_retry_time` is INDEFINITE_TIME, it shall be set using get_time()]
+		else if (retry_control->first_retry_time == INDEFINITE_TIME && (retry_control->first_retry_time = get_time(NULL)) == INDEFINITE_TIME)
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_012: [If get_time() fails, `retry_control_should_retry` shall fail and return non-zero]
+			LogError("Failed to evaluate if retry should be attempted (get_time() failed)");
+			result = __FAILURE__;
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_013: [evaluate_retry_action() shall be invoked]
+		else if (evaluate_retry_action(retry_control, retry_action) != RESULT_OK)
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_014: [If evaluate_retry_action() fails, `retry_control_should_retry` shall fail and return non-zero]
+			LogError("Failed to evaluate if retry should be attempted (evaluate_retry_action() failed)");
+			result = __FAILURE__;
+		}
+		else
+		{
+			if (*retry_action == RETRY_ACTION_RETRY_NOW)
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_015: [If `retry_action` is set to RETRY_ACTION_RETRY_NOW, `retry_control->retry_count` shall be incremented by 1]
+				retry_control->retry_count++;
+
+				if (retry_control->policy != IOTHUB_CLIENT_RETRY_IMMEDIATE)
+				{
+					// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_016: [If `retry_action` is set to RETRY_ACTION_RETRY_NOW and policy is not IOTHUB_CLIENT_RETRY_IMMEDIATE, `retry_control->last_retry_time` shall be set using get_time()]
+					retry_control->last_retry_time = get_time(NULL);
+
+					// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_017: [If `retry_action` is set to RETRY_ACTION_RETRY_NOW and policy is not IOTHUB_CLIENT_RETRY_IMMEDIATE, `retry_control->current_wait_time_in_secs` shall be set using calculate_next_wait_time()]
+					retry_control->current_wait_time_in_secs = calculate_next_wait_time(retry_control);
+				}
+			}
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_018: [If no errors occur, `retry_control_should_retry` shall return 0]
+			result = RESULT_OK;
+		}
+	}
+
+	return result;
+}
+
+int retry_control_set_option(RETRY_CONTROL_HANDLE retry_control_handle, const char* name, const void* value)
+{
+	int result;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_036: [If `retry_control_handle`, `name` or `value` are NULL, `retry_control_set_option` shall fail and return non-zero]
+	if (retry_control_handle == NULL || name == NULL || value == NULL)
+	{
+		LogError("Failed to set option (either retry_state_handle (%p), name (%p) or value (%p) are NULL)", retry_control_handle, name, value);
+		result = __FAILURE__;
+	}
+	else
+	{
+		RETRY_CONTROL_INSTANCE* retry_control = (RETRY_CONTROL_INSTANCE*)retry_control_handle;
+
+		if (strcmp(RETRY_CONTROL_OPTION_INITIAL_WAIT_TIME_IN_SECS, name) == 0)
+		{
+			unsigned int cast_value = *((unsigned int*)value);
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_037: [If `name` is "initial_wait_time_in_secs" and `value` is less than 1, `retry_control_set_option` shall fail and return non-zero]
+			if (cast_value < 1)
+			{
+				LogError("Failed to set option '%s' (value must be equal or greater to 1)", name);
+				result = __FAILURE__;
+			}
+			else
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_038: [If `name` is "initial_wait_time_in_secs", `value` shall be saved on `retry_control->initial_wait_time_in_secs`]
+				retry_control->initial_wait_time_in_secs = cast_value;
+
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_044: [If no errors occur, retry_control_set_option shall return 0]
+				result = RESULT_OK;
+			}
+		}
+		else if (strcmp(RETRY_CONTROL_OPTION_MAX_JITTER_PERCENT, name) == 0)
+		{
+			unsigned int cast_value = *((unsigned int*)value);
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_039: [If `name` is "max_jitter_percent" and `value` is less than 0 or greater than 100, `retry_control_set_option` shall fail and return non-zero]
+			if (cast_value > 100) // it's unsigned int, it doesn't need to be checked for less than zero.
+			{
+				LogError("Failed to set option '%s' (value must be in the range 0 to 100)", name);
+				result = __FAILURE__;
+			}
+			else
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_040: [If `name` is "max_jitter_percent", value shall be saved on `retry_control->max_jitter_percent`]
+				retry_control->max_jitter_percent = cast_value;
+
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_044: [If no errors occur, retry_control_set_option shall return 0]
+				result = RESULT_OK;
+			}
+		}
+		else if (strcmp(RETRY_CONTROL_OPTION_SAVED_OPTIONS, name) == 0)
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_041: [If `name` is "retry_control_options", value shall be fed to `retry_control` using OptionHandler_FeedOptions]
+			if (OptionHandler_FeedOptions((OPTIONHANDLER_HANDLE)value, retry_control_handle) != OPTIONHANDLER_OK)
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_042: [If OptionHandler_FeedOptions fails, `retry_control_set_option` shall fail and return non-zero]
+				LogError("messenger_set_option failed (OptionHandler_FeedOptions failed)");
+				result = __FAILURE__;
+			}
+			else
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_044: [If no errors occur, `retry_control_set_option` shall return 0]
+				result = RESULT_OK;
+			}
+		}
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_043: [If `name` is not a supported option, `retry_control_set_option` shall fail and return non-zero]
+		else
+		{
+			LogError("messenger_set_option failed (option with name '%s' is not suppported)", name);
+			result = __FAILURE__;
+		}
+	}
+
+	return result;
+}
+
+OPTIONHANDLER_HANDLE retry_control_retrieve_options(RETRY_CONTROL_HANDLE retry_control_handle)
+{
+	OPTIONHANDLER_HANDLE result;
+
+	// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_045: [If `retry_control_handle`, `retry_control_retrieve_options` shall fail and return NULL]
+	if (retry_control_handle == NULL)
+	{
+		LogError("Failed to retrieve options (retry_state_handle is NULL)");
+		result = NULL;
+	}
+	else
+	{
+		// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_046: [An instance of OPTIONHANDLER_HANDLE (a.k.a. `options`) shall be created using OptionHandler_Create]
+		OPTIONHANDLER_HANDLE options = OptionHandler_Create(retry_control_clone_option, retry_control_destroy_option, (pfSetOption)retry_control_set_option);
+
+		if (options == NULL)
+		{
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_047: [If OptionHandler_Create fails, `retry_control_retrieve_options` shall fail and return NULL]
+			LogError("Failed to retrieve options (OptionHandler_Create failed)");
+			result = NULL;
+		}
+		else
+		{
+			RETRY_CONTROL_INSTANCE* retry_control = (RETRY_CONTROL_INSTANCE*)retry_control_handle;
+
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_050: [`retry_control->initial_wait_time_in_secs` shall be added to `options` using OptionHandler_Add]
+			if (OptionHandler_AddOption(options, RETRY_CONTROL_OPTION_INITIAL_WAIT_TIME_IN_SECS, (void*)&retry_control->initial_wait_time_in_secs) != OPTIONHANDLER_OK)
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_052: [If any call to OptionHandler_Add fails, `retry_control_retrieve_options` shall fail and return NULL]
+				LogError("Failed to retrieve options (OptionHandler_Create failed for option '%s')", RETRY_CONTROL_OPTION_INITIAL_WAIT_TIME_IN_SECS);
+				result = NULL;
+			}
+			// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_051: [`retry_control->max_jitter_percent` shall be added to `options` using OptionHandler_Add]
+			else if (OptionHandler_AddOption(options, RETRY_CONTROL_OPTION_MAX_JITTER_PERCENT, (void*)&retry_control->max_jitter_percent) != OPTIONHANDLER_OK)
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_052: [If any call to OptionHandler_Add fails, `retry_control_retrieve_options` shall fail and return NULL]
+				LogError("Failed to retrieve options (OptionHandler_Create failed for option '%s')", RETRY_CONTROL_OPTION_INITIAL_WAIT_TIME_IN_SECS);
+				result = NULL;
+			}
+			else
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_054: [If no errors occur, `retry_control_retrieve_options` shall return the OPTIONHANDLER_HANDLE instance]
+				result = options;
+			}
+
+			if (result == NULL)
+			{
+				// Codes_SRS_IOTHUB_CLIENT_RETRY_CONTROL_09_053: [If any failures occur, `retry_control_retrieve_options` shall release any memory it has allocated]
+				OptionHandler_Destroy(options);
+			}
+		}
+	}
+
+	return result;
+}
\ No newline at end of file