/*
 *  Copyright (c) 2016, The OpenThread Authors.
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @file
 * @brief
 *  This file defines the OpenThread IPv6 API.
 */

#ifndef OPENTHREAD_IP6_H_
#define OPENTHREAD_IP6_H_

#include <openthread/message.h>
#include <openthread/platform/radio.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @addtogroup api-ip6
 *
 * @brief
 *   This module includes functions that control IPv6 communication.
 *
 * @{
 *
 */

#define OT_IP6_PREFIX_SIZE 8                           ///< Size of an IPv6 prefix (bytes)
#define OT_IP6_PREFIX_BITSIZE (OT_IP6_PREFIX_SIZE * 8) ///< Size of an IPv6 prefix (bits)
#define OT_IP6_IID_SIZE 8                              ///< Size of an IPv6 Interface Identifier (bytes)
#define OT_IP6_ADDRESS_SIZE 16                         ///< Size of an IPv6 address (bytes)

/**
 * @struct otIp6InterfaceIdentifier
 *
 * This structure represents the Interface Identifier of an IPv6 address.
 *
 */
OT_TOOL_PACKED_BEGIN
struct otIp6InterfaceIdentifier
{
    union OT_TOOL_PACKED_FIELD
    {
        uint8_t  m8[OT_IP6_IID_SIZE];                     ///< 8-bit fields
        uint16_t m16[OT_IP6_IID_SIZE / sizeof(uint16_t)]; ///< 16-bit fields
        uint32_t m32[OT_IP6_IID_SIZE / sizeof(uint32_t)]; ///< 32-bit fields
    } mFields;                                            ///< The Interface Identifier accessor fields
} OT_TOOL_PACKED_END;

/**
 * This structure represents the Interface Identifier of an IPv6 address.
 *
 */
typedef struct otIp6InterfaceIdentifier otIp6InterfaceIdentifier;

/**
 * @struct otIp6NetworkPrefix
 *
 * This structure represents the Network Prefix of an IPv6 address (most significant 64 bits of the address).
 *
 */
OT_TOOL_PACKED_BEGIN
struct otIp6NetworkPrefix
{
    uint8_t m8[OT_IP6_PREFIX_SIZE]; ///< The Network Prefix.
} OT_TOOL_PACKED_END;

/**
 * This structure represents the Network Prefix of an IPv6 address (most significant 64 bits of the address).
 *
 */
typedef struct otIp6NetworkPrefix otIp6NetworkPrefix;

/**
 * @struct otIp6AddressComponents
 *
 * This structure represents the components of an IPv6 address.
 *
 */
OT_TOOL_PACKED_BEGIN
struct otIp6AddressComponents
{
    otIp6NetworkPrefix       mNetworkPrefix; ///< The Network Prefix (most significant 64 bits of the address)
    otIp6InterfaceIdentifier mIid;           ///< The Interface Identifier (least significant 64 bits of the address)
} OT_TOOL_PACKED_END;

/**
 * This structure represents the components of an IPv6 address.
 *
 */
typedef struct otIp6AddressComponents otIp6AddressComponents;

/**
 * @struct otIp6Address
 *
 * This structure represents an IPv6 address.
 *
 */
OT_TOOL_PACKED_BEGIN
struct otIp6Address
{
    union OT_TOOL_PACKED_FIELD
    {
        uint8_t                m8[OT_IP6_ADDRESS_SIZE];                     ///< 8-bit fields
        uint16_t               m16[OT_IP6_ADDRESS_SIZE / sizeof(uint16_t)]; ///< 16-bit fields
        uint32_t               m32[OT_IP6_ADDRESS_SIZE / sizeof(uint32_t)]; ///< 32-bit fields
        otIp6AddressComponents mComponents;                                 ///< IPv6 address components
    } mFields;                                                              ///< IPv6 accessor fields
} OT_TOOL_PACKED_END;

/**
 * This structure represents an IPv6 address.
 *
 */
typedef struct otIp6Address otIp6Address;

/**
 * This structure represents an IPv6 prefix.
 *
 */
OT_TOOL_PACKED_BEGIN
struct otIp6Prefix
{
    otIp6Address mPrefix; ///< The IPv6 prefix.
    uint8_t      mLength; ///< The IPv6 prefix length (in bits).
} OT_TOOL_PACKED_END;

/**
 * This structure represents an IPv6 prefix.
 *
 */
typedef struct otIp6Prefix otIp6Prefix;

/**
 * IPv6 Address origins
 *
 */
enum
{
    OT_ADDRESS_ORIGIN_THREAD = 0, ///< Thread assigned address (ALOC, RLOC, MLEID, etc)
    OT_ADDRESS_ORIGIN_SLAAC  = 1, ///< SLAAC assigned address
    OT_ADDRESS_ORIGIN_DHCPV6 = 2, ///< DHCPv6 assigned address
    OT_ADDRESS_ORIGIN_MANUAL = 3, ///< Manually assigned address
};

/**
 * This structure represents an IPv6 network interface unicast address.
 *
 */
typedef struct otNetifAddress
{
    otIp6Address           mAddress;                ///< The IPv6 unicast address.
    uint8_t                mPrefixLength;           ///< The Prefix length (in bits).
    uint8_t                mAddressOrigin;          ///< The IPv6 address origin.
    bool                   mPreferred : 1;          ///< TRUE if the address is preferred, FALSE otherwise.
    bool                   mValid : 1;              ///< TRUE if the address is valid, FALSE otherwise.
    bool                   mScopeOverrideValid : 1; ///< TRUE if the mScopeOverride value is valid, FALSE otherwise.
    unsigned int           mScopeOverride : 4;      ///< The IPv6 scope of this address.
    bool                   mRloc : 1;               ///< TRUE if the address is an RLOC, FALSE otherwise.
    struct otNetifAddress *mNext;                   ///< A pointer to the next network interface address.
} otNetifAddress;

/**
 * This structure represents an IPv6 network interface multicast address.
 *
 */
typedef struct otNetifMulticastAddress
{
    otIp6Address                          mAddress; ///< The IPv6 multicast address.
    const struct otNetifMulticastAddress *mNext;    ///< A pointer to the next network interface multicast address.
} otNetifMulticastAddress;

/**
 * This structure represents an IPv6 socket address.
 *
 */
typedef struct otSockAddr
{
    otIp6Address mAddress; ///< An IPv6 address.
    uint16_t     mPort;    ///< A transport-layer port.
    int8_t       mScopeId; ///< An IPv6 scope identifier.
} otSockAddr;

/**
 * This structure represents the local and peer IPv6 socket addresses.
 *
 */
typedef struct otMessageInfo
{
    otIp6Address mSockAddr;      ///< The local IPv6 address.
    otIp6Address mPeerAddr;      ///< The peer IPv6 address.
    uint16_t     mSockPort;      ///< The local transport-layer port.
    uint16_t     mPeerPort;      ///< The peer transport-layer port.
    const void * mLinkInfo;      ///< A pointer to link-specific information.
    uint8_t      mHopLimit;      ///< The IPv6 Hop Limit value. Only applies if `mAllowZeroHopLimit` is FALSE.
                                 ///< If `0`, IPv6 Hop Limit is default value `OPENTHREAD_CONFIG_IP6_HOP_LIMIT_DEFAULT`.
                                 ///< Otherwise, specifies the IPv6 Hop Limit.
    bool mIsHostInterface : 1;   ///< TRUE if packets sent/received via host interface, FALSE otherwise.
    bool mAllowZeroHopLimit : 1; ///< TRUE to allow IPv6 Hop Limit 0 in `mHopLimit`, FALSE otherwise.
} otMessageInfo;

/**
 * This function brings up/down the IPv6 interface.
 *
 * Call this function to enable/disable IPv6 communication.
 *
 * @param[in] aInstance A pointer to an OpenThread instance.
 * @param[in] aEnabled  TRUE to enable IPv6, FALSE otherwise.
 *
 * @retval OT_ERROR_NONE            Successfully brought the IPv6 interface up/down.
 * @retval OT_ERROR_INVALID_STATE   IPv6 interface is not available since device is operating in raw-link mode
 *                                  (applicable only when `OPENTHREAD_CONFIG_LINK_RAW_ENABLE` feature is enabled).
 *
 */
otError otIp6SetEnabled(otInstance *aInstance, bool aEnabled);

/**
 * This function indicates whether or not the IPv6 interface is up.
 *
 * @param[in] aInstance A pointer to an OpenThread instance.
 *
 * @retval TRUE   The IPv6 interface is enabled.
 * @retval FALSE  The IPv6 interface is disabled.
 *
 */
bool otIp6IsEnabled(otInstance *aInstance);

/**
 * Add a Network Interface Address to the Thread interface.
 *
 * The passed-in instance @p aAddress is copied by the Thread interface. The Thread interface only
 * supports a fixed number of externally added unicast addresses. See OPENTHREAD_CONFIG_IP6_MAX_EXT_UCAST_ADDRS.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aAddress  A pointer to a Network Interface Address.
 *
 * @retval OT_ERROR_NONE          Successfully added (or updated) the Network Interface Address.
 * @retval OT_ERROR_INVALID_ARGS  The IP Address indicated by @p aAddress is an internal address.
 * @retval OT_ERROR_NO_BUFS       The Network Interface is already storing the maximum allowed external addresses.
 */
otError otIp6AddUnicastAddress(otInstance *aInstance, const otNetifAddress *aAddress);

/**
 * Remove a Network Interface Address from the Thread interface.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aAddress  A pointer to an IP Address.
 *
 * @retval OT_ERROR_NONE          Successfully removed the Network Interface Address.
 * @retval OT_ERROR_INVALID_ARGS  The IP Address indicated by @p aAddress is an internal address.
 * @retval OT_ERROR_NOT_FOUND     The IP Address indicated by @p aAddress was not found.
 */
otError otIp6RemoveUnicastAddress(otInstance *aInstance, const otIp6Address *aAddress);

/**
 * Get the list of IPv6 addresses assigned to the Thread interface.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 *
 * @returns A pointer to the first Network Interface Address.
 */
const otNetifAddress *otIp6GetUnicastAddresses(otInstance *aInstance);

/**
 * Subscribe the Thread interface to a Network Interface Multicast Address.
 *
 * The passed in instance @p aAddress will be copied by the Thread interface. The Thread interface only
 * supports a fixed number of externally added multicast addresses. See OPENTHREAD_CONFIG_IP6_MAX_EXT_MCAST_ADDRS.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aAddress  A pointer to an IP Address.
 *
 * @retval OT_ERROR_NONE           Successfully subscribed to the Network Interface Multicast Address.
 * @retval OT_ERROR_ALREADY        The multicast address is already subscribed.
 * @retval OT_ERROR_INVALID_ARGS   The IP Address indicated by @p aAddress is invalid address.
 * @retval OT_ERROR_INVALID_STATE  The Network Interface is not up.
 * @retval OT_ERROR_NO_BUFS        The Network Interface is already storing the maximum allowed external multicast
 *                                 addresses.
 *
 */
otError otIp6SubscribeMulticastAddress(otInstance *aInstance, const otIp6Address *aAddress);

/**
 * Unsubscribe the Thread interface to a Network Interface Multicast Address.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aAddress  A pointer to an IP Address.
 *
 * @retval OT_ERROR_NONE          Successfully unsubscribed to the Network Interface Multicast Address.
 * @retval OT_ERROR_INVALID_ARGS  The IP Address indicated by @p aAddress is an internal address.
 * @retval OT_ERROR_NOT_FOUND     The IP Address indicated by @p aAddress was not found.
 */
otError otIp6UnsubscribeMulticastAddress(otInstance *aInstance, const otIp6Address *aAddress);

/**
 * Get the list of IPv6 multicast addresses subscribed to the Thread interface.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 *
 * @returns A pointer to the first Network Interface Multicast Address.
 *
 */
const otNetifMulticastAddress *otIp6GetMulticastAddresses(otInstance *aInstance);

/**
 * Check if multicast promiscuous mode is enabled on the Thread interface.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 *
 * @sa otIp6SetMulticastPromiscuousEnabled
 *
 */
bool otIp6IsMulticastPromiscuousEnabled(otInstance *aInstance);

/**
 * Enable multicast promiscuous mode on the Thread interface.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 * @param[in]  aEnabled   TRUE to enable Multicast Promiscuous mode, FALSE otherwise.
 *
 * @sa otIp6IsMulticastPromiscuousEnabled
 *
 */
void otIp6SetMulticastPromiscuousEnabled(otInstance *aInstance, bool aEnabled);

/**
 * Allocate a new message buffer for sending an IPv6 message.
 *
 * @note If @p aSettings is 'NULL', the link layer security is enabled and the message priority is set to
 * OT_MESSAGE_PRIORITY_NORMAL by default.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 * @param[in]  aSettings  A pointer to the message settings or NULL to set default settings.
 *
 * @returns A pointer to the message buffer or NULL if no message buffers are available or parameters are invalid.
 *
 * @sa otMessageFree
 *
 */
otMessage *otIp6NewMessage(otInstance *aInstance, const otMessageSettings *aSettings);

/**
 * Allocate a new message buffer and write the IPv6 datagram to the message buffer for sending an IPv6 message.
 *
 * @note If @p aSettings is NULL, the link layer security is enabled and the message priority is obtained from IPv6
 *       message itself.
 *       If @p aSettings is not NULL, the @p aSetting->mPriority is ignored and obtained from IPv6 message itself.
 *
 * @param[in]  aInstance    A pointer to an OpenThread instance.
 * @param[in]  aData        A pointer to the IPv6 datagram buffer.
 * @param[in]  aDataLength  The size of the IPv6 datagram buffer pointed by @p aData.
 * @param[in]  aSettings    A pointer to the message settings or NULL to set default settings.
 *
 * @returns A pointer to the message or NULL if malformed IPv6 header or insufficient message buffers are available.
 *
 * @sa otMessageFree
 *
 */
otMessage *otIp6NewMessageFromBuffer(otInstance *             aInstance,
                                     const uint8_t *          aData,
                                     uint16_t                 aDataLength,
                                     const otMessageSettings *aSettings);

/**
 * This function pointer is called when an IPv6 datagram is received.
 *
 * @param[in]  aMessage  A pointer to the message buffer containing the received IPv6 datagram. This function transfers
 *                       the ownership of the @p aMessage to the receiver of the callback. The message should be
 *                       freed by the receiver of the callback after it is processed (see otMessageFree()).
 * @param[in]  aContext  A pointer to application-specific context.
 *
 */
typedef void (*otIp6ReceiveCallback)(otMessage *aMessage, void *aContext);

/**
 * This function registers a callback to provide received IPv6 datagrams.
 *
 * By default, this callback does not pass Thread control traffic.  See otIp6SetReceiveFilterEnabled() to
 * change the Thread control traffic filter setting.
 *
 * @param[in]  aInstance         A pointer to an OpenThread instance.
 * @param[in]  aCallback         A pointer to a function that is called when an IPv6 datagram is received or
 *                               NULL to disable the callback.
 * @param[in]  aCallbackContext  A pointer to application-specific context.
 *
 * @sa otIp6IsReceiveFilterEnabled
 * @sa otIp6SetReceiveFilterEnabled
 *
 */
void otIp6SetReceiveCallback(otInstance *aInstance, otIp6ReceiveCallback aCallback, void *aCallbackContext);

/**
 * This function pointer is called when an internal IPv6 address is added or removed.
 *
 * @param[in]   aAddress            A pointer to the IPv6 address.
 * @param[in]   aPrefixLength       The prefix length if @p aAddress is unicast address, and 128 for multicast address.
 * @param[in]   aIsAdded            TRUE if the @p aAddress was added, FALSE if @p aAddress was removed.
 * @param[in]   aContext            A pointer to application-specific context.
 *
 */
typedef void (*otIp6AddressCallback)(const otIp6Address *aAddress,
                                     uint8_t             aPrefixLength,
                                     bool                aIsAdded,
                                     void *              aContext);

/**
 * This function registers a callback to notify internal IPv6 address changes.
 *
 * @param[in]   aInstance           A pointer to an OpenThread instance.
 * @param[in]   aCallback           A pointer to a function that is called when an internal IPv6 address is added or
 *                                  removed. NULL to disable the callback.
 * @param[in]   aCallbackContext    A pointer to application-specific context.
 *
 */
void otIp6SetAddressCallback(otInstance *aInstance, otIp6AddressCallback aCallback, void *aCallbackContext);

/**
 * This function indicates whether or not Thread control traffic is filtered out when delivering IPv6 datagrams
 * via the callback specified in otIp6SetReceiveCallback().
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 *
 * @returns  TRUE if Thread control traffic is filtered out, FALSE otherwise.
 *
 * @sa otIp6SetReceiveCallback
 * @sa otIp6SetReceiveFilterEnabled
 *
 */
bool otIp6IsReceiveFilterEnabled(otInstance *aInstance);

/**
 * This function sets whether or not Thread control traffic is filtered out when delivering IPv6 datagrams
 * via the callback specified in otIp6SetReceiveCallback().
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aEnabled  TRUE if Thread control traffic is filtered out, FALSE otherwise.
 *
 * @sa otIp6SetReceiveCallback
 * @sa otIsReceiveIp6FilterEnabled
 *
 */
void otIp6SetReceiveFilterEnabled(otInstance *aInstance, bool aEnabled);

/**
 * This function sends an IPv6 datagram via the Thread interface.
 *
 * The caller transfers ownership of @p aMessage when making this call. OpenThread will free @p aMessage when
 * processing is complete, including when a value other than `OT_ERROR_NONE` is returned.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aMessage  A pointer to the message buffer containing the IPv6 datagram.
 *
 * @retval OT_ERROR_NONE      Successfully processed the message.
 * @retval OT_ERROR_DROP      Message was well-formed but not fully processed due to packet processing rules.
 * @retval OT_ERROR_NO_BUFS   Could not allocate necessary message buffers when processing the datagram.
 * @retval OT_ERROR_NO_ROUTE  No route to host.
 * @retval OT_ERROR_PARSE     Encountered a malformed header when processing the message.
 *
 */
otError otIp6Send(otInstance *aInstance, otMessage *aMessage);

/**
 * This function adds a port to the allowed unsecured port list.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aPort     The port value.
 *
 * @retval OT_ERROR_NONE         The port was successfully added to the allowed unsecure port list.
 * @retval OT_ERROR_INVALID_ARGS The port is invalid (value 0 is reserved for internal use).
 * @retval OT_ERROR_NO_BUFS      The unsecure port list is full.
 *
 */
otError otIp6AddUnsecurePort(otInstance *aInstance, uint16_t aPort);

/**
 * This function removes a port from the allowed unsecure port list.
 *
 * @note This function removes @p aPort by overwriting @p aPort with the element after @p aPort in the internal port
 *       list. Be careful when calling otIp6GetUnsecurePorts() followed by otIp6RemoveUnsecurePort() to remove unsecure
 *       ports.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 * @param[in]  aPort     The port value.
 *
 * @retval OT_ERROR_NONE         The port was successfully removed from the allowed unsecure port list.
 * @retval OT_ERROR_INVALID_ARGS The port is invalid (value 0 is reserved for internal use).
 * @retval OT_ERROR_NOT_FOUND    The port was not found in the unsecure port list.
 *
 */
otError otIp6RemoveUnsecurePort(otInstance *aInstance, uint16_t aPort);

/**
 * This function removes all ports from the allowed unsecure port list.
 *
 * @param[in]  aInstance A pointer to an OpenThread instance.
 *
 */
void otIp6RemoveAllUnsecurePorts(otInstance *aInstance);

/**
 * This function returns a pointer to the unsecure port list.
 *
 * @note Port value 0 is used to indicate an invalid entry.
 *
 * @param[in]   aInstance    A pointer to an OpenThread instance.
 * @param[out]  aNumEntries  The number of entries in the list.
 *
 * @returns A pointer to the unsecure port list.
 *
 */
const uint16_t *otIp6GetUnsecurePorts(otInstance *aInstance, uint8_t *aNumEntries);

/**
 * Test if two IPv6 addresses are the same.
 *
 * @param[in]  aFirst   A pointer to the first IPv6 address to compare.
 * @param[in]  aSecond  A pointer to the second IPv6 address to compare.
 *
 * @retval TRUE   The two IPv6 addresses are the same.
 * @retval FALSE  The two IPv6 addresses are not the same.
 *
 */
bool otIp6IsAddressEqual(const otIp6Address *aFirst, const otIp6Address *aSecond);

/**
 * Convert a human-readable IPv6 address string into a binary representation.
 *
 * @param[in]   aString   A pointer to a NULL-terminated string.
 * @param[out]  aAddress  A pointer to an IPv6 address.
 *
 * @retval OT_ERROR_NONE          Successfully parsed the string.
 * @retval OT_ERROR_INVALID_ARGS  Failed to parse the string.
 *
 */
otError otIp6AddressFromString(const char *aString, otIp6Address *aAddress);

/**
 * This function returns the prefix match length (bits) for two IPv6 addresses.
 *
 * @param[in]  aFirst   A pointer to the first IPv6 address.
 * @param[in]  aSecond  A pointer to the second IPv6 address.
 *
 * @returns  The prefix match length in bits.
 *
 */
uint8_t otIp6PrefixMatch(const otIp6Address *aFirst, const otIp6Address *aSecond);

/**
 * This function indicates whether or not a given IPv6 address is the Unspecified Address.
 *
 * @param[in]  aAddress   A pointer to an IPv6 address.
 *
 * @retval TRUE   If the IPv6 address is the Unspecified Address.
 * @retval FALSE  If the IPv6 address is not the Unspecified Address.
 *
 */
bool otIp6IsAddressUnspecified(const otIp6Address *aAddress);

/**
 * This function perform OpenThread source address selection.
 *
 * @param[in]     aInstance     A pointer to an OpenThread instance.
 * @param[inout]  aMessageInfo  A pointer to the message information.
 *
 * @retval  OT_ERROR_NONE       Found a source address and is filled into mSockAddr of @p aMessageInfo.
 * @retval  OT_ERROR_NOT_FOUND  No source address was found and @p aMessageInfo is unchanged.
 *
 */
otError otIp6SelectSourceAddress(otInstance *aInstance, otMessageInfo *aMessageInfo);

/**
 * This function indicates whether the SLAAC module is enabled or not.
 *
 * This function requires the build-time feature `OPENTHREAD_CONFIG_IP6_SLAAC_ENABLE` to be enabled.
 *
 * @retval TRUE    SLAAC module is enabled.
 * @retval FALSE   SLAAC module is disabled.
 *
 */
bool otIp6IsSlaacEnabled(otInstance *aInstance);

/**
 * This function enables/disables the SLAAC module.
 *
 * This function requires the build-time feature `OPENTHREAD_CONFIG_IP6_SLAAC_ENABLE` to be enabled.
 *
 * When SLAAC module is enabled, SLAAC addresses (based on on-mesh prefixes in Network Data) are added to the interface.
 * When SLAAC module is disabled any previously added SLAAC address is removed.
 *
 * @param[in] aInstance A pointer to an OpenThread instance.
 * @param[in] aEnabled  TRUE to enable, FALSE to disable.
 *
 */
void otIp6SetSlaacEnabled(otInstance *aInstance, bool aEnabled);

/**
 * This function pointer allows user to filter prefixes and not allow an SLAAC address based on a prefix to be added.
 *
 * `otIp6SetSlaacPrefixFilter()` can be used to set the filter handler. The filter handler is invoked by SLAAC module
 * when it is about to add a SLAAC address based on a prefix. Its boolean return value determines whether the address
 * is filtered (not added) or not.
 *
 * @param[in] aInstacne   A pointer to an OpenThread instance.
 * @param[in] aPrefix     A pointer to prefix for which SLAAC address is about to be added.
 *
 * @retval TRUE    Indicates that the SLAAC address based on the prefix should be filtered and NOT added.
 * @retval FALSE   Indicates that the SLAAC address based on the prefix should be added.
 *
 */
typedef bool (*otIp6SlaacPrefixFilter)(otInstance *aInstance, const otIp6Prefix *aPrefix);

/**
 * This function sets the SLAAC module filter handler.
 *
 * This function requires the build-time feature `OPENTHREAD_CONFIG_IP6_SLAAC_ENABLE` to be enabled.
 *
 * The filter handler is called by SLAAC module when it is about to add a SLAAC address based on a prefix to decide
 * whether the address should be added or not.
 *
 * A NULL filter handler disables filtering and allows all SLAAC addresses to be added.
 *
 * If this function is not called, the default filter used by SLAAC module will be NULL (filtering is disabled).
 *
 * @param[in] aInstance    A pointer to an OpenThread instance.
 * @param[in] aFilter      A pointer to SLAAC prefix filter handler, or NULL to disable filtering.
 *
 */
void otIp6SetSlaacPrefixFilter(otInstance *aInstance, otIp6SlaacPrefixFilter aFilter);

/**
 * @}
 *
 */

#ifdef __cplusplus
} // extern "C"
#endif

#endif // OPENTHREAD_IP6_H_