include/openthread/srp_server.h

/*
 *  Copyright (c) 2020, The OpenThread Authors.
 *  All rights reserved.
 *
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 *  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
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/**
 * @file
 * @brief
 *  This file defines the API for server of the Service Registration Protocol (SRP).
 */

#ifndef OPENTHREAD_SRP_SERVER_H_
#define OPENTHREAD_SRP_SERVER_H_

#include <stdint.h>

#include <openthread/dns.h>
#include <openthread/instance.h>
#include <openthread/ip6.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @addtogroup api-srp
 *
 * @brief
 *  This module includes functions of the Service Registration Protocol.
 *
 * @{
 *
 */

/**
 * This opaque type represents a SRP service host.
 *
 */
typedef struct otSrpServerHost otSrpServerHost;

/**
 * This opaque type represents a SRP service.
 *
 */
typedef struct otSrpServerService otSrpServerService;

/**
 * The ID of a SRP service update transaction on the SRP Server.
 *
 */
typedef uint32_t otSrpServerServiceUpdateId;

/**
 * The service flag type to indicate which services to include or exclude when searching in (or iterating over) the
 * list of SRP services.
 *
 * This is a combination of bit-flags. The specific bit-flags are defined in the enumeration `OT_SRP_SERVER_FLAG_*`.
 *
 */
typedef uint8_t otSrpServerServiceFlags;

enum
{
    OT_SRP_SERVER_SERVICE_FLAG_BASE_TYPE = 1 << 0, ///< Include base services (not a sub-type).
    OT_SRP_SERVER_SERVICE_FLAG_SUB_TYPE  = 1 << 1, ///< Include sub-type services.
    OT_SRP_SERVER_SERVICE_FLAG_ACTIVE    = 1 << 2, ///< Include active (not deleted) services.
    OT_SRP_SERVER_SERVICE_FLAG_DELETED   = 1 << 3, ///< Include deleted services.
};

enum
{
    /**
     * This constant defines an `otSrpServerServiceFlags` combination accepting any service (base/sub-type,
     * active/deleted).
     *
     */
    OT_SRP_SERVER_FLAGS_ANY_SERVICE = (OT_SRP_SERVER_SERVICE_FLAG_BASE_TYPE | OT_SRP_SERVER_SERVICE_FLAG_SUB_TYPE |
                                       OT_SRP_SERVER_SERVICE_FLAG_ACTIVE | OT_SRP_SERVER_SERVICE_FLAG_DELETED),

    /**
     * This constant defines an `otSrpServerServiceFlags` combination accepting base service only.
     *
     */
    OT_SRP_SERVER_FLAGS_BASE_TYPE_SERVICE_ONLY =
        (OT_SRP_SERVER_SERVICE_FLAG_BASE_TYPE | OT_SRP_SERVER_SERVICE_FLAG_ACTIVE | OT_SRP_SERVER_SERVICE_FLAG_DELETED),

    /**
     * This constant defines an `otSrpServerServiceFlags` combination accepting sub-type service only.
     *
     */
    OT_SRP_SERVER_FLAGS_SUB_TYPE_SERVICE_ONLY =
        (OT_SRP_SERVER_SERVICE_FLAG_SUB_TYPE | OT_SRP_SERVER_SERVICE_FLAG_ACTIVE | OT_SRP_SERVER_SERVICE_FLAG_DELETED),

    /**
     * This constant defines an `otSrpServerServiceFlags` combination accepting any active service (not deleted).
     *
     */
    OT_SRP_SERVER_FLAGS_ANY_TYPE_ACTIVE_SERVICE =
        (OT_SRP_SERVER_SERVICE_FLAG_BASE_TYPE | OT_SRP_SERVER_SERVICE_FLAG_SUB_TYPE |
         OT_SRP_SERVER_SERVICE_FLAG_ACTIVE),

    /**
     * This constant defines an `otSrpServerServiceFlags` combination accepting any deleted service.
     *
     */
    OT_SRP_SERVER_FLAGS_ANY_TYPE_DELETED_SERVICE =
        (OT_SRP_SERVER_SERVICE_FLAG_BASE_TYPE | OT_SRP_SERVER_SERVICE_FLAG_SUB_TYPE |
         OT_SRP_SERVER_SERVICE_FLAG_ACTIVE),
};

/**
 * Represents the state of an SRP server
 *
 */
typedef enum
{
    OT_SRP_SERVER_STATE_DISABLED = 0, ///< The SRP server is disabled.
    OT_SRP_SERVER_STATE_RUNNING  = 1, ///< The SRP server is running.
    OT_SRP_SERVER_STATE_STOPPED  = 2, ///< The SRP server is stopped.
} otSrpServerState;

/**
 * This enumeration represents the address mode used by the SRP server.
 *
 * Address mode specifies how the address and port number are determined by the SRP server and how this info is
 * published in the Thread Network Data.
 *
 */
typedef enum otSrpServerAddressMode
{
    OT_SRP_SERVER_ADDRESS_MODE_UNICAST = 0, ///< Unicast address mode.
    OT_SRP_SERVER_ADDRESS_MODE_ANYCAST = 1, ///< Anycast address mode.
} otSrpServerAddressMode;

/**
 * This structure includes SRP server LEASE and KEY-LEASE configurations.
 *
 */
typedef struct otSrpServerLeaseConfig
{
    uint32_t mMinLease;    ///< The minimum LEASE interval in seconds.
    uint32_t mMaxLease;    ///< The maximum LEASE interval in seconds.
    uint32_t mMinKeyLease; ///< The minimum KEY-LEASE interval in seconds.
    uint32_t mMaxKeyLease; ///< The maximum KEY-LEASE interval in seconds.
} otSrpServerLeaseConfig;

/**
 * This function returns the domain authorized to the SRP server.
 *
 * If the domain if not set by SetDomain, "default.service.arpa." will be returned.
 * A trailing dot is always appended even if the domain is set without it.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 *
 * @returns A pointer to the dot-joined domain string.
 *
 */
const char *otSrpServerGetDomain(otInstance *aInstance);

/**
 * This function sets the domain on the SRP server.
 *
 * A trailing dot will be appended to @p aDomain if it is not already there.
 * This function should only be called before the SRP server is enabled.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 * @param[in]  aDomain    The domain to be set. MUST NOT be NULL.
 *
 * @retval  OT_ERROR_NONE           Successfully set the domain to @p aDomain.
 * @retval  OT_ERROR_INVALID_STATE  The SRP server is already enabled and the Domain cannot be changed.
 * @retval  OT_ERROR_INVALID_ARGS   The argument @p aDomain is not a valid DNS domain name.
 * @retval  OT_ERROR_NO_BUFS        There is no memory to store content of @p aDomain.
 *
 */
otError otSrpServerSetDomain(otInstance *aInstance, const char *aDomain);

/**
 * This function returns the state of the SRP server.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 *
 * @returns The current state of the SRP server.
 *
 */
otSrpServerState otSrpServerGetState(otInstance *aInstance);

/**
 * This function returns the address mode being used by the SRP server.
 *
 * @param[in] aInstance  A pointer to an OpenThread instance.
 *
 * @returns The SRP server's address mode.
 *
 */
otSrpServerAddressMode otSrpServerGetAddressMode(otInstance *aInstance);

/**
 * This function sets the address mode to be used by the SRP server.
 *
 * @param[in] aInstance  A pointer to an OpenThread instance.
 * @param[in] aMode      The address mode to use.
 *
 * @retval OT_ERROR_NONE           Successfully set the address mode.
 * @retval OT_ERROR_INVALID_STATE  The SRP server is enabled and the address mode cannot be changed.
 *
 */
otError otSrpServerSetAddressMode(otInstance *aInstance, otSrpServerAddressMode aMode);

/**
 * This function returns the sequence number used with anycast address mode.
 *
 * The sequence number is included in "DNS/SRP Service Anycast Address" entry published in the Network Data.
 *
 * @param[in] aInstance  A pointer to an OpenThread instance.
 *
 * @returns The anycast sequence number.
 *
 */
uint8_t otSrpServerGetAnycastModeSequenceNumber(otInstance *aInstance);

/**
 * This function sets the sequence number used with anycast address mode.
 *
 * @param[in] aInstance        A pointer to an OpenThread instance.
 * @param[in] aSequenceNumber  The sequence number to use.
 *
 * @retval OT_ERROR_NONE            Successfully set the address mode.
 * @retval OT_ERROR_INVALID_STATE   The SRP server is enabled and the sequence number cannot be changed.
 *
 */
otError otSrpServerSetAnycastModeSequenceNumber(otInstance *aInstance, uint8_t aSequenceNumber);

/**
 * This function enables/disables the SRP server.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 * @param[in]  aEnabled   A boolean to enable/disable the SRP server.
 *
 */
void otSrpServerSetEnabled(otInstance *aInstance, bool aEnabled);

/**
 * This function returns SRP server LEASE and KEY-LEASE configurations.
 *
 * @param[in]   aInstance     A pointer to an OpenThread instance.
 * @param[out]  aLeaseConfig  A pointer to an `otSrpServerLeaseConfig` instance.
 *
 */
void otSrpServerGetLeaseConfig(otInstance *aInstance, otSrpServerLeaseConfig *aLeaseConfig);

/**
 * This function sets SRP server LEASE and KEY-LEASE configurations.
 *
 * When a non-zero LEASE time is requested from a client, the granted value will be
 * limited in range [aMinLease, aMaxLease]; and a non-zero KEY-LEASE will be granted
 * in range [aMinKeyLease, aMaxKeyLease]. For zero LEASE or KEY-LEASE time, zero will
 * be granted.
 *
 * @param[in]  aInstance     A pointer to an OpenThread instance.
 * @param[in]  aLeaseConfig  A pointer to an `otSrpServerLeaseConfig` instance.
 *
 * @retval  OT_ERROR_NONE          Successfully set the LEASE and KEY-LEASE ranges.
 * @retval  OT_ERROR_INVALID_ARGS  The LEASE or KEY-LEASE range is not valid.
 *
 */
otError otSrpServerSetLeaseConfig(otInstance *aInstance, const otSrpServerLeaseConfig *aLeaseConfig);

/**
 * This function handles SRP service updates.
 *
 * This function is called by the SRP server to notify that a SRP host and possibly SRP services
 * are being updated. It is important that the SRP updates are not committed until the handler
 * returns the result by calling otSrpServerHandleServiceUpdateResult or times out after @p aTimeout.
 *
 * A SRP service observer should always call otSrpServerHandleServiceUpdateResult with error code
 * OT_ERROR_NONE immediately after receiving the update events.
 *
 * A more generic handler may perform validations on the SRP host/services and rejects the SRP updates
 * if any validation fails. For example, an Advertising Proxy should advertise (or remove) the host and
 * services on a multicast-capable link and returns specific error code if any failure occurs.
 *
 * @param[in]  aId       The service update transaction ID. This ID must be passed back with
 *                       `otSrpServerHandleServiceUpdateResult`.
 * @param[in]  aHost     A pointer to the otSrpServerHost object which contains the SRP updates. The
 *                       handler should publish/un-publish the host and each service points to this
 *                       host with below rules:
 *                         1. If the host is not deleted (indicated by `otSrpServerHostIsDeleted`),
 *                            then it should be published or updated with mDNS. Otherwise, the host
 *                            should be un-published (remove AAAA RRs).
 *                         2. For each service points to this host, it must be un-published if the host
 *                            is to be un-published. Otherwise, the handler should publish or update the
 *                            service when it is not deleted (indicated by `otSrpServerServiceIsDeleted`)
 *                            and un-publish it when deleted.
 * @param[in]  aTimeout  The maximum time in milliseconds for the handler to process the service event.
 * @param[in]  aContext  A pointer to application-specific context.
 *
 * @sa otSrpServerSetServiceUpdateHandler
 * @sa otSrpServerHandleServiceUpdateResult
 *
 */
typedef void (*otSrpServerServiceUpdateHandler)(otSrpServerServiceUpdateId aId,
                                                const otSrpServerHost *    aHost,
                                                uint32_t                   aTimeout,
                                                void *                     aContext);

/**
 * This function sets the SRP service updates handler on SRP server.
 *
 * @param[in]  aInstance        A pointer to an OpenThread instance.
 * @param[in]  aServiceHandler  A pointer to a service handler. Use NULL to remove the handler.
 * @param[in]  aContext         A pointer to arbitrary context information.
 *                              May be NULL if not used.
 *
 */
void otSrpServerSetServiceUpdateHandler(otInstance *                    aInstance,
                                        otSrpServerServiceUpdateHandler aServiceHandler,
                                        void *                          aContext);

/**
 * This function reports the result of processing a SRP update to the SRP server.
 *
 * The Service Update Handler should call this function to return the result of its
 * processing of a SRP update.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 * @param[in]  aId        The service update transaction ID. This should be the same ID
 *                        provided via `otSrpServerServiceUpdateHandler`.
 * @param[in]  aError     An error to be returned to the SRP server. Use OT_ERROR_DUPLICATED
 *                        to represent DNS name conflicts.
 *
 */
void otSrpServerHandleServiceUpdateResult(otInstance *aInstance, otSrpServerServiceUpdateId aId, otError aError);

/**
 * This function returns the next registered host on the SRP server.
 *
 * @param[in]  aInstance  A pointer to an OpenThread instance.
 * @param[in]  aHost      A pointer to current host; use NULL to get the first host.
 *
 * @returns  A pointer to the registered host. NULL, if no more hosts can be found.
 *
 */
const otSrpServerHost *otSrpServerGetNextHost(otInstance *aInstance, const otSrpServerHost *aHost);

/**
 * This function tells if the SRP service host has been deleted.
 *
 * A SRP service host can be deleted but retains its name for future uses.
 * In this case, the host instance is not removed from the SRP server/registry.
 *
 * @param[in]  aHost  A pointer to the SRP service host.
 *
 * @returns  TRUE if the host has been deleted, FALSE if not.
 *
 */
bool otSrpServerHostIsDeleted(const otSrpServerHost *aHost);

/**
 * This function returns the full name of the host.
 *
 * @param[in]  aHost  A pointer to the SRP service host.
 *
 * @returns  A pointer to the null-terminated host name string.
 *
 */
const char *otSrpServerHostGetFullName(const otSrpServerHost *aHost);

/**
 * This function returns the addresses of given host.
 *
 * @param[in]   aHost          A pointer to the SRP service host.
 * @param[out]  aAddressesNum  A pointer to where we should output the number of the addresses to.
 *
 * @returns  A pointer to the array of IPv6 Address.
 *
 */
const otIp6Address *otSrpServerHostGetAddresses(const otSrpServerHost *aHost, uint8_t *aAddressesNum);

/**
 * This function returns the next service (excluding any sub-type services) of given host.
 *
 * @note This function is being deprecated and will be removed. `otSrpServerHostFindNextService()` can be used
 *       instead.
 *
 * @param[in]  aHost     A pointer to the SRP service host.
 * @param[in]  aService  A pointer to current SRP service instance; use NULL to get the first service.
 *
 * @returns  A pointer to the next service or NULL if there is no more services.
 *
 */
const otSrpServerService *otSrpServerHostGetNextService(const otSrpServerHost *   aHost,
                                                        const otSrpServerService *aService);

/**
 * This function finds the next matching service on the host.
 *
 * The combination of flags and service and instance names enables iterating over the full list of services and/or a
 * subset of them matching certain conditions, or finding a specific service.
 *
 * To iterate over all services of a host:
 *   service = otSrpServerHostFindNextService(host, service, OT_SRP_SERVER_FLAGS_ANY_SERVICE, NULL, NULL);
 *
 * To iterate over base services only (exclude sub-types):
 *   service = otSrpServerHostFindNextService(host, service, OT_SRP_SERVER_FLAGS_BASE_TYPE_SERVICE_ONLY, NULL, NULL);
 *
 * To iterate over sub-types of a specific instance name `instanceName`:
 *   service = otSrpServerHostFindNextService(host, service, OT_SRP_SERVER_FLAGS_SUB_TYPE_SERVICE_ONLY, NULL,
 *                                            instanceName);
 *
 * To find a specific service with service name `serviceName` and service instance name `instanceName`:
 *   service = otSrpServerHostFindNextService(host, NULL, OT_SRP_SERVER_FLAGS_ANY_SERVICE, serviceName, instanceName);
 *
 * To find the base type service with a given service instance name `instanceName`:
 *   service = otSrpServerHostFindNextService(host, NULL, OT_SRP_SERVER_FLAGS_BASE_TYPE_SERVICE_ONLY, NULL,
 *                                            instanceName);
 *
 * @param[in] aHost          A pointer to the SRP service host (MUST NOT be NULL).
 * @param[in] aPrevService   A pointer to the previous service or NULL to start from the beginning of the list.
 * @param[in] aFlags         Flags indicating which services to include (base/sub-type, active/deleted).
 * @param[in] aServiceName   The service name to match. Set to NULL to accept any name.
 * @param[in] aInstanceName  The service instance name to match. Set to NULL to accept any name.
 *
 * @returns  A pointer to the next matching service or NULL if no matching service could be found.
 *
 */
const otSrpServerService *otSrpServerHostFindNextService(const otSrpServerHost *   aHost,
                                                         const otSrpServerService *aPrevService,
                                                         otSrpServerServiceFlags   aFlags,
                                                         const char *              aServiceName,
                                                         const char *              aInstanceName);

/**
 * This function indicates whether or not the SRP service has been deleted.
 *
 * A SRP service can be deleted but retains its name for future uses.
 * In this case, the service instance is not removed from the SRP server/registry.
 * It is guaranteed that all services are deleted if the host is deleted.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  TRUE if the service has been deleted, FALSE if not.
 *
 */
bool otSrpServerServiceIsDeleted(const otSrpServerService *aService);

/**
 * This function indicates whether or not the SRP service is sub-type.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  TRUE if the service is a sub-type, FALSE if not.
 *
 */
bool otSrpServerServiceIsSubType(const otSrpServerService *aService);

/**
 * This function returns the full service instance name of the service.
 *
 * @note This function is being deprecated and will be removed. `otSrpServerServiceGetInstanceName()` can be used
 *       instead.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  A pointer to the null-terminated service instance name string.
 *
 */
const char *otSrpServerServiceGetFullName(const otSrpServerService *aService);

/**
 * This function returns the full service instance name of the service.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  A pointer to the null-terminated service instance name string.
 *
 */
const char *otSrpServerServiceGetInstanceName(const otSrpServerService *aService);

/**
 * This function returns the full service name of the service.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  A pointer to the null-terminated service name string.
 *
 */
const char *otSrpServerServiceGetServiceName(const otSrpServerService *aService);

/**
 * This function gets the sub-type label from service name.
 *
 * This function is intended to be used when the @p aService is a sub-type, i.e., `otSrpServerServiceIsSubType()` for
 * the service returns TRUE. If it is not a sub-type this function returns `OT_ERROR_INVALID_ARGS`.
 *
 * The full service name for a sub-type service follows "<sub-label>._sub.<service-labels>.<domain>.". This function
 * copies the `<sub-label>` into the @p aLabel buffer.
 *
 * The @p aLabel is ensured to always be null-terminated after returning even in case of failure.
 *
 * @param[in]  aService           A pointer to the SRP service.
 * @param[out] aLabel             A pointer to a buffer to copy the sub-type label name into.
 * @param[in]  aMaxSize           Maximum size of @p aLabel buffer.
 *
 * @retval OT_ERROR_NONE          @p aLabel was updated successfully.
 * @retval OT_ERROR_NO_BUFS       The sub-type label could not fit in @p aLabel buffer (number of chars from label
 *                                that could fit are copied in @p aLabel ensuring it is null-terminated).
 * @retval OT_ERROR_INVALID_ARGS  SRP service is not a sub-type.
 *
 */
otError otSrpServerServiceGetServiceSubTypeLabel(const otSrpServerService *aService, char *aLabel, uint8_t aMaxSize);

/**
 * This function returns the port of the service instance.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  The port of the service.
 *
 */
uint16_t otSrpServerServiceGetPort(const otSrpServerService *aService);

/**
 * This function returns the weight of the service instance.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  The weight of the service.
 *
 */
uint16_t otSrpServerServiceGetWeight(const otSrpServerService *aService);

/**
 * This function returns the priority of the service instance.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  The priority of the service.
 *
 */
uint16_t otSrpServerServiceGetPriority(const otSrpServerService *aService);

/**
 * This function returns the TXT record data of the service instance.
 *
 * @param[in]  aService        A pointer to the SRP service.
 * @param[out] aDataLength     A pointer to return the TXT record data length. MUST NOT be NULL.
 *
 * @returns A pointer to the buffer containing the TXT record data (the TXT data length is returned in @p aDataLength).
 *
 */
const uint8_t *otSrpServerServiceGetTxtData(const otSrpServerService *aService, uint16_t *aDataLength);

/**
 * This function returns the host which the service instance reside on.
 *
 * @param[in]  aService  A pointer to the SRP service.
 *
 * @returns  A pointer to the host instance.
 *
 */
const otSrpServerHost *otSrpServerServiceGetHost(const otSrpServerService *aService);

/**
 * @}
 *
 */

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

#endif // OPENTHREAD_SRP_SERVER_H_