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/*
*
* Copyright (c) 2020-2021 Project CHIP Authors
* Copyright (c) 2017 Nest Labs, Inc.
* All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* This file defines the configuration parameters that are required
* for the CHIP Reliable Messaging Protocol.
*
*/
#pragma once
#include <lib/core/CHIPConfig.h>
#include <lib/core/Optional.h>
#include <system/SystemClock.h>
#include <system/SystemConfig.h>
namespace chip {
/**
* @def CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL
*
* @brief Base retry interval of the present node when it is in the active state.
*
* Base interval that a peer node should use to calculate the retransmission
* timeout when it sends a message to the present node and the present node is
* perceived by the peer as active.
*
* This value is announced to the peer using SAI (Session Active Interval) key
* in the advertised DNS Service Discovery TXT records. Additionally, it is
* exchanged in the initial phase of the PASE/CASE session establishment.
*
* In the case of a Thread device, the default value is increased to limit the
* possibility of spurious retransmissions. The assumption is that the average
* round-trip time of a big request-response pair is substantially longer in
* a Thread network that potentially constists of multiple intermediate hops.
*/
#ifndef CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL
#if CHIP_ENABLE_OPENTHREAD && !CHIP_DEVICE_LAYER_TARGET_LINUX
#define CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL (2000_ms32)
#else
#define CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL (300_ms32)
#endif
#endif // CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL && !CHIP_DEVICE_LAYER_TARGET_LINUX
/**
* @def CHIP_CONFIG_MRP_LOCAL_IDLE_RETRY_INTERVAL
*
* @brief Base retry interval of the present node when it is in the idle state.
*
* Base interval that a peer node should use to calculate the retransmission
* timeout when it sends a message to the present node and the present node is
* perceived by the peer as idle.
*
* This value is announced to the peer using SII (Session Idle Interval) key
* in the advertised DNS Service Discovery TXT records. Additionally, it is
* exchanged in the initial phase of the PASE/CASE session establishment.
*
* In the case of a Thread device, the default value is increased to limit the
* possibility of spurious retransmissions. The assumption is that the average
* round-trip time of a big request-response pair is substantially longer in
* a Thread network that potentially constists of multiple intermediate hops.
*/
#ifndef CHIP_CONFIG_MRP_LOCAL_IDLE_RETRY_INTERVAL
#if CHIP_ENABLE_OPENTHREAD && !CHIP_DEVICE_LAYER_TARGET_LINUX
#define CHIP_CONFIG_MRP_LOCAL_IDLE_RETRY_INTERVAL (2000_ms32)
#else
#define CHIP_CONFIG_MRP_LOCAL_IDLE_RETRY_INTERVAL (500_ms32)
#endif
#endif // CHIP_CONFIG_MRP_LOCAL_IDLE_RETRY_INTERVAL && !CHIP_DEVICE_LAYER_TARGET_LINUX
/**
* @def CHIP_CONFIG_RMP_DEFAULT_ACK_TIMEOUT
*
* @brief
* The default acknowledgment timeout in milliseconds.
*
*/
#ifndef CHIP_CONFIG_RMP_DEFAULT_ACK_TIMEOUT
#define CHIP_CONFIG_RMP_DEFAULT_ACK_TIMEOUT (200_ms32)
#endif // CHIP_CONFIG_RMP_DEFAULT_ACK_TIMEOUT
/**
* @def CHIP_CONFIG_RESOLVE_PEER_ON_FIRST_TRANSMIT_FAILURE
*
* @brief
* Should an address lookup of the peer happen on every first message that fails
* to send on the link.
*
* The default value to not perform lookup was selected because most implementations
* of address lookup are not cache the and a request is sent on the link. Failing
* to deliver the first message is far more likely to happen due to lossy link
* than an actual address change where the peer did not reset. In the lossy link
* situation, doing further DNS resolutions on a degraded link can exacerbate that
* problem greatly. Additionally, every message that arrives from a peer updates the
* address. If the peer has fallen off the link due to any other reason, a re-resolve
* may not achieve an address that is reachable, even if a resolve response occurs.
*/
#ifndef CHIP_CONFIG_RESOLVE_PEER_ON_FIRST_TRANSMIT_FAILURE
#define CHIP_CONFIG_RESOLVE_PEER_ON_FIRST_TRANSMIT_FAILURE 0
#endif // CHIP_CONFIG_RESOLVE_PEER_ON_FIRST_TRANSMIT_FAILURE
/**
* @def CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE
*
* @brief
* The default size of the ReliableMessageProtocol retransmission table.
*
*/
#ifndef CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE
#if CHIP_SYSTEM_CONFIG_USE_LWIP
#if !CHIP_SYSTEM_CONFIG_LWIP_PBUF_FROM_CUSTOM_POOL && PBUF_POOL_SIZE != 0
// Configure the table size to be less than the number of packet buffers to make sure
// that not all buffers are held by the retransmission entries, in which case the device
// is unable to receive an ACK and hence becomes unavailable until a message times out.
#define CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE std::min(PBUF_POOL_SIZE - 1, CHIP_CONFIG_MAX_EXCHANGE_CONTEXTS)
#else
#define CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE CHIP_CONFIG_MAX_EXCHANGE_CONTEXTS
#endif // !CHIP_SYSTEM_CONFIG_LWIP_PBUF_FROM_CUSTOM_POOL && PBUF_POOL_SIZE != 0
#else // CHIP_SYSTEM_CONFIG_USE_LWIP
#if CHIP_SYSTEM_CONFIG_PACKETBUFFER_POOL_SIZE != 0
// Configure the table size to be less than the number of packet buffers to make sure
// that not all buffers are held by the retransmission entries, in which case the device
// is unable to receive an ACK and hence becomes unavailable until a message times out.
#define CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE \
std::min(CHIP_SYSTEM_CONFIG_PACKETBUFFER_POOL_SIZE - 1, CHIP_CONFIG_MAX_EXCHANGE_CONTEXTS)
#else
#define CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE CHIP_CONFIG_MAX_EXCHANGE_CONTEXTS
#endif // CHIP_SYSTEM_CONFIG_PACKETBUFFER_POOL_SIZE != 0
#endif // CHIP_SYSTEM_CONFIG_USE_LWIP
#endif // CHIP_CONFIG_RMP_RETRANS_TABLE_SIZE
/**
* @def CHIP_CONFIG_RMP_DEFAULT_MAX_RETRANS
*
* @brief
* The maximum number of retransmissions before giving up.
*
*/
#ifndef CHIP_CONFIG_RMP_DEFAULT_MAX_RETRANS
#define CHIP_CONFIG_RMP_DEFAULT_MAX_RETRANS (4)
#endif // CHIP_CONFIG_RMP_DEFAULT_MAX_RETRANS
/**
* @def CHIP_CONFIG_MRP_RETRY_INTERVAL_SENDER_BOOST
*
* @brief
* A constant value that should be added to the calculated retransmission
* timeout when the present node transmits a message.
*
* The purpose for this constant is to limit the possibility of spurious
* retransmissions in the scenario in which a sender that operates in a high-
* latency network (such as Thread) sends a message to a receiver that operates
* in a low-latency network (such as Wi-Fi). In this scenario, the SAI and SII
* parameters advertised by the receiver are low although the average round-
* trip time of a big request-response pair is long due to the nature of the
* sender.
*/
#ifndef CHIP_CONFIG_MRP_RETRY_INTERVAL_SENDER_BOOST
#if CHIP_ENABLE_OPENTHREAD && !CHIP_DEVICE_LAYER_TARGET_LINUX
#define CHIP_CONFIG_MRP_RETRY_INTERVAL_SENDER_BOOST (1500_ms)
#else
#define CHIP_CONFIG_MRP_RETRY_INTERVAL_SENDER_BOOST (0_ms)
#endif
#endif // CHIP_CONFIG_MRP_RETRY_INTERVAL_SENDER_BOOST
inline constexpr System::Clock::Milliseconds32 kDefaultActiveTime = System::Clock::Milliseconds16(4000);
/**
* @brief
* The ReliableMessageProtocol configuration.
*/
struct ReliableMessageProtocolConfig
{
ReliableMessageProtocolConfig(System::Clock::Milliseconds32 idleInterval, System::Clock::Milliseconds32 activeInterval,
System::Clock::Milliseconds16 activeThreshold = kDefaultActiveTime) :
mIdleRetransTimeout(idleInterval),
mActiveRetransTimeout(activeInterval), mActiveThresholdTime(activeThreshold)
{}
// Configurable timeout in msec for retransmission of the first sent message.
System::Clock::Milliseconds32 mIdleRetransTimeout;
// Configurable timeout in msec for retransmission of all subsequent messages.
System::Clock::Milliseconds32 mActiveRetransTimeout;
// Configurable amount of time the node SHOULD stay active after network activity.
System::Clock::Milliseconds16 mActiveThresholdTime;
bool operator==(const ReliableMessageProtocolConfig & that) const
{
return mIdleRetransTimeout == that.mIdleRetransTimeout && mActiveRetransTimeout == that.mActiveRetransTimeout &&
mActiveThresholdTime == that.mActiveThresholdTime;
}
#if CHIP_DEVICE_CONFIG_ENABLE_DYNAMIC_MRP_CONFIG
/**
* Set the local MRP configuration for the node.
*
* Passing a "no value" optional resets to the compiled-in settings
* (CHIP_CONFIG_MRP_LOCAL_IDLE_RETRY_INTERVAL and
* CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL).
*
* Otherwise the value set via this function is used instead of the
* compiled-in settings, but can still be overridden by ICD configuration
* and other things that would override the compiled-in settings.
*
* Changing the value via this function does not affect any existing
* sessions or exchanges, but does affect the values we communicate to our
* peer during future session establishments.
*
* @return whether the local MRP configuration actually changed as a result
* of this call. If it did, callers may need to reset DNS-SD
* advertising to advertise the updated values.
*/
static bool SetLocalMRPConfig(const Optional<ReliableMessageProtocolConfig> & localMRPConfig);
#endif // CHIP_DEVICE_CONFIG_ENABLE_DYNAMIC_MRP_CONFIG
};
/// @brief The default MRP config. The value is defined by spec, and shall be same for all implementations,
ReliableMessageProtocolConfig GetDefaultMRPConfig();
/**
* @brief The custom value of MRP config for the platform.
* @return Missing If the value is same as default value defined by spec
* Value The custom value for the platform
*
* @note This value is not used by our MRP manager. The value is advertised via mDNS or during PASE/CASE paring, and our peers
* use it when communicating with us.
*/
Optional<ReliableMessageProtocolConfig> GetLocalMRPConfig();
/**
* @brief
* Returns the maximum transmission time depending on the last activity time.
*
* @param[in] activeInterval The active interval to use for the backoff calculation.
* @param[in] idleInterval The idle interval to use for the backoff calculation.
* @param[in] lastActivityTime The last time some activity has been recorded.
* @param[in] activityThreshold The activity threshold for a node to be considered active.
*
* @return The maximum transmission time
*/
System::Clock::Timeout GetRetransmissionTimeout(System::Clock::Timeout activeInterval, System::Clock::Timeout idleInterval,
System::Clock::Timeout lastActivityTime, System::Clock::Timeout activityThreshold);
#if CONFIG_BUILD_FOR_HOST_UNIT_TEST
/**
* @brief
*
* Overrides the local idle and active retransmission timeout parameters (which are usually set through compile
* time defines). This is reserved for tests that need the ability to set these at runtime to make certain test scenarios possible.
*
*/
void OverrideLocalMRPConfig(System::Clock::Timeout idleRetransTimeout, System::Clock::Timeout activeRetransTimeout,
System::Clock::Timeout activeThresholdTime = kDefaultActiveTime);
/**
* @brief
*
* Disables the overrides set previously in OverrideLocalMRPConfig().
*
*/
void ClearLocalMRPConfigOverride();
#endif
} // namespace chip