/* * Copyright (c) 2017-2021, 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 top-level DNS functions for the OpenThread library. */ #ifndef OPENTHREAD_DNS_CLIENT_H_ #define OPENTHREAD_DNS_CLIENT_H_ #include #include #include #ifdef __cplusplus extern "C" { #endif /** * @addtogroup api-dns * * @brief * This module includes functions that control DNS communication. * * The functions in this module are available only if feature `OPENTHREAD_CONFIG_DNS_CLIENT_ENABLE` is enabled. * * @{ * */ /** * Type represents the "Recursion Desired" (RD) flag in an `otDnsQueryConfig`. * */ typedef enum { OT_DNS_FLAG_UNSPECIFIED = 0, ///< Indicates the flag is not specified. OT_DNS_FLAG_RECURSION_DESIRED = 1, ///< Indicates DNS name server can resolve the query recursively. OT_DNS_FLAG_NO_RECURSION = 2, ///< Indicates DNS name server can not resolve the query recursively. } otDnsRecursionFlag; /** * Type represents the NAT64 mode in an `otDnsQueryConfig`. * * The NAT64 mode indicates whether to allow or disallow NAT64 address translation during DNS client address resolution. * This mode is only used when `OPENTHREAD_CONFIG_DNS_CLIENT_NAT64_ENABLE` is enabled. * */ typedef enum { OT_DNS_NAT64_UNSPECIFIED = 0, ///< NAT64 mode is not specified. Use default NAT64 mode. OT_DNS_NAT64_ALLOW = 1, ///< Allow NAT64 address translation during DNS client address resolution. OT_DNS_NAT64_DISALLOW = 2, ///< Do not allow NAT64 address translation during DNS client address resolution. } otDnsNat64Mode; /** * Type represents the service resolution mode in an `otDnsQueryConfig`. * * This is only used during DNS client service resolution `otDnsClientResolveService()`. It determines which * record types to query. * */ typedef enum { OT_DNS_SERVICE_MODE_UNSPECIFIED = 0, ///< Mode is not specified. Use default service mode. OT_DNS_SERVICE_MODE_SRV = 1, ///< Query for SRV record only. OT_DNS_SERVICE_MODE_TXT = 2, ///< Query for TXT record only. OT_DNS_SERVICE_MODE_SRV_TXT = 3, ///< Query for both SRV and TXT records in same message. OT_DNS_SERVICE_MODE_SRV_TXT_SEPARATE = 4, ///< Query in parallel for SRV and TXT using separate messages. OT_DNS_SERVICE_MODE_SRV_TXT_OPTIMIZE = 5, ///< Query for TXT/SRV together first, if fails then query separately. } otDnsServiceMode; /** * Type represents the DNS transport protocol in an `otDnsQueryConfig`. * * This `OT_DNS_TRANSPORT_TCP` is only supported when `OPENTHREAD_CONFIG_DNS_CLIENT_OVER_TCP_ENABLE` is enabled. * */ typedef enum { OT_DNS_TRANSPORT_UNSPECIFIED = 0, /// DNS transport is unspecified. OT_DNS_TRANSPORT_UDP = 1, /// DNS query should be sent via UDP. OT_DNS_TRANSPORT_TCP = 2, /// DNS query should be sent via TCP. } otDnsTransportProto; /** * Represents a DNS query configuration. * * Any of the fields in this structure can be set to zero to indicate that it is not specified. How the unspecified * fields are treated is determined by the function which uses the instance of `otDnsQueryConfig`. * */ typedef struct otDnsQueryConfig { otSockAddr mServerSockAddr; ///< Server address (IPv6 addr/port). All zero or zero port for unspecified. uint32_t mResponseTimeout; ///< Wait time (in msec) to rx response. Zero indicates unspecified value. uint8_t mMaxTxAttempts; ///< Maximum tx attempts before reporting failure. Zero for unspecified value. otDnsRecursionFlag mRecursionFlag; ///< Indicates whether the server can resolve the query recursively or not. otDnsNat64Mode mNat64Mode; ///< Allow/Disallow NAT64 address translation during address resolution. otDnsServiceMode mServiceMode; ///< Determines which records to query during service resolution. otDnsTransportProto mTransportProto; ///< Select default transport protocol. } otDnsQueryConfig; /** * Gets the current default query config used by DNS client. * * When OpenThread stack starts, the default DNS query config is determined from a set of OT config options such as * `OPENTHREAD_CONFIG_DNS_CLIENT_DEFAULT_SERVER_IP6_ADDRESS`, `_DEFAULT_SERVER_PORT`, `_DEFAULT_RESPONSE_TIMEOUT`, etc. * (see `config/dns_client.h` for all related config options). * * @param[in] aInstance A pointer to an OpenThread instance. * * @returns A pointer to the current default config being used by DNS client. * */ const otDnsQueryConfig *otDnsClientGetDefaultConfig(otInstance *aInstance); /** * Sets the default query config on DNS client. * * @note Any ongoing query will continue to use the config from when it was started. The new default config will be * used for any future DNS queries. * * The @p aConfig can be NULL. In this case the default config will be set to the defaults from OT config options * `OPENTHREAD_CONFIG_DNS_CLIENT_DEFAULT_{}`. This resets the default query config back to to the config when the * OpenThread stack starts. * * In a non-NULL @p aConfig, caller can choose to leave some of the fields in `otDnsQueryConfig` instance unspecified * (value zero). The unspecified fields are replaced by the corresponding OT config option definitions * `OPENTHREAD_CONFIG_DNS_CLIENT_DEFAULT_{}` to form the default query config. * * When `OPENTHREAD_CONFIG_DNS_CLIENT_DEFAULT_SERVER_ADDRESS_AUTO_SET_ENABLE` is enabled, the server's IPv6 address in * the default config is automatically set and updated by DNS client. This is done only when user does not explicitly * set or specify it. This behavior requires SRP client and its auto-start feature to be enabled. SRP client will then * monitor the Thread Network Data for DNS/SRP Service entries to select an SRP server. The selected SRP server address * is also set as the DNS server address in the default config. * * @param[in] aInstance A pointer to an OpenThread instance. * @param[in] aConfig A pointer to the new query config to use as default. * */ void otDnsClientSetDefaultConfig(otInstance *aInstance, const otDnsQueryConfig *aConfig); /** * An opaque representation of a response to an address resolution DNS query. * * Pointers to instance of this type are provided from callback `otDnsAddressCallback`. * */ typedef struct otDnsAddressResponse otDnsAddressResponse; /** * Pointer is called when a DNS response is received for an address resolution query. * * Within this callback the user can use `otDnsAddressResponseGet{Item}()` functions along with the @p aResponse * pointer to get more info about the response. * * The @p aResponse pointer can only be used within this callback and after returning from this function it will not * stay valid, so the user MUST NOT retain the @p aResponse pointer for later use. * * @param[in] aError The result of the DNS transaction. * @param[in] aResponse A pointer to the response (it is always non-NULL). * @param[in] aContext A pointer to application-specific context. * * The @p aError can have the following: * * - OT_ERROR_NONE A response was received successfully. * - OT_ERROR_ABORT A DNS transaction was aborted by stack. * - OT_ERROR_RESPONSE_TIMEOUT No DNS response has been received within timeout. * * If the server rejects the address resolution request the error code from server is mapped as follow: * * - (0) NOERROR Success (no error condition) -> OT_ERROR_NONE * - (1) FORMERR Server unable to interpret due to format error -> OT_ERROR_PARSE * - (2) SERVFAIL Server encountered an internal failure -> OT_ERROR_FAILED * - (3) NXDOMAIN Name that ought to exist, does not exist -> OT_ERROR_NOT_FOUND * - (4) NOTIMP Server does not support the query type (OpCode) -> OT_ERROR_NOT_IMPLEMENTED * - (5) REFUSED Server refused for policy/security reasons -> OT_ERROR_SECURITY * - (6) YXDOMAIN Some name that ought not to exist, does exist -> OT_ERROR_DUPLICATED * - (7) YXRRSET Some RRset that ought not to exist, does exist -> OT_ERROR_DUPLICATED * - (8) NXRRSET Some RRset that ought to exist, does not exist -> OT_ERROR_NOT_FOUND * - (9) NOTAUTH Service is not authoritative for zone -> OT_ERROR_SECURITY * - (10) NOTZONE A name is not in the zone -> OT_ERROR_PARSE * - (20) BADNAME Bad name -> OT_ERROR_PARSE * - (21) BADALG Bad algorithm -> OT_ERROR_SECURITY * - (22) BADTRUN Bad truncation -> OT_ERROR_PARSE * - Other response codes -> OT_ERROR_FAILED * */ typedef void (*otDnsAddressCallback)(otError aError, const otDnsAddressResponse *aResponse, void *aContext); /** * Sends an address resolution DNS query for AAAA (IPv6) record(s) for a given host name. * * The @p aConfig can be NULL. In this case the default config (from `otDnsClientGetDefaultConfig()`) will be used as * the config for this query. In a non-NULL @p aConfig, some of the fields can be left unspecified (value zero). The * unspecified fields are then replaced by the values from the default config. * * @param[in] aInstance A pointer to an OpenThread instance. * @param[in] aHostName The host name for which to query the address (MUST NOT be NULL). * @param[in] aCallback A function pointer that shall be called on response reception or time-out. * @param[in] aContext A pointer to arbitrary context information. * @param[in] aConfig A pointer to the config to use for this query. * * @retval OT_ERROR_NONE Query sent successfully. @p aCallback will be invoked to report the status. * @retval OT_ERROR_NO_BUFS Insufficient buffer to prepare and send query. * @retval OT_ERROR_INVALID_ARGS The host name is not valid format. * @retval OT_ERROR_INVALID_STATE Cannot send query since Thread interface is not up. * */ otError otDnsClientResolveAddress(otInstance *aInstance, const char *aHostName, otDnsAddressCallback aCallback, void *aContext, const otDnsQueryConfig *aConfig); /** * Sends an address resolution DNS query for A (IPv4) record(s) for a given host name. * * Requires and is available when `OPENTHREAD_CONFIG_DNS_CLIENT_NAT64_ENABLE` is enabled. * * When a successful response is received, the addresses are returned from @p aCallback as NAT64 IPv6 translated * versions of the IPv4 addresses from the query response. * * The @p aConfig can be NULL. In this case the default config (from `otDnsClientGetDefaultConfig()`) will be used as * the config for this query. In a non-NULL @p aConfig, some of the fields can be left unspecified (value zero). The * unspecified fields are then replaced by the values from the default config. * * @param[in] aInstance A pointer to an OpenThread instance. * @param[in] aHostName The host name for which to query the address (MUST NOT be NULL). * @param[in] aCallback A function pointer that shall be called on response reception or time-out. * @param[in] aContext A pointer to arbitrary context information. * @param[in] aConfig A pointer to the config to use for this query. * * @retval OT_ERROR_NONE Query sent successfully. @p aCallback will be invoked to report the status. * @retval OT_ERROR_NO_BUFS Insufficient buffer to prepare and send query. * @retval OT_ERROR_INVALID_ARGS The host name is not valid format or NAT64 is not enabled in config. * @retval OT_ERROR_INVALID_STATE Cannot send query since Thread interface is not up. * */ otError otDnsClientResolveIp4Address(otInstance *aInstance, const char *aHostName, otDnsAddressCallback aCallback, void *aContext, const otDnsQueryConfig *aConfig); /** * Gets the full host name associated with an address resolution DNS response. * * MUST only be used from `otDnsAddressCallback`. * * @param[in] aResponse A pointer to the response. * @param[out] aNameBuffer A buffer to char array to output the full host name (MUST NOT be NULL). * @param[in] aNameBufferSize The size of @p aNameBuffer. * * @retval OT_ERROR_NONE The full host name was read successfully. * @retval OT_ERROR_NO_BUFS The name does not fit in @p aNameBuffer. * */ otError otDnsAddressResponseGetHostName(const otDnsAddressResponse *aResponse, char *aNameBuffer, uint16_t aNameBufferSize); /** * Gets an IPv6 address associated with an address resolution DNS response. * * MUST only be used from `otDnsAddressCallback`. * * The response may include multiple IPv6 address records. @p aIndex can be used to iterate through the list of * addresses. Index zero gets the first address and so on. When we reach end of the list, `OT_ERROR_NOT_FOUND` is * returned. * * @param[in] aResponse A pointer to the response. * @param[in] aIndex The address record index to retrieve. * @param[out] aAddress A pointer to a IPv6 address to output the address (MUST NOT be NULL). * @param[out] aTtl A pointer to an `uint32_t` to output TTL for the address. It can be NULL if caller does not * want to get the TTL. * * @retval OT_ERROR_NONE The address was read successfully. * @retval OT_ERROR_NOT_FOUND No address record in @p aResponse at @p aIndex. * @retval OT_ERROR_PARSE Could not parse the records in the @p aResponse. * @retval OT_ERROR_INVALID_STATE No NAT64 prefix (applicable only when NAT64 is allowed). * */ otError otDnsAddressResponseGetAddress(const otDnsAddressResponse *aResponse, uint16_t aIndex, otIp6Address *aAddress, uint32_t *aTtl); /** * An opaque representation of a response to a browse (service instance enumeration) DNS query. * * Pointers to instance of this type are provided from callback `otDnsBrowseCallback`. * */ typedef struct otDnsBrowseResponse otDnsBrowseResponse; /** * Pointer is called when a DNS response is received for a browse (service instance enumeration) query. * * Within this callback the user can use `otDnsBrowseResponseGet{Item}()` functions along with the @p aResponse * pointer to get more info about the response. * * The @p aResponse pointer can only be used within this callback and after returning from this function it will not * stay valid, so the user MUST NOT retain the @p aResponse pointer for later use. * * @param[in] aError The result of the DNS transaction. * @param[in] aResponse A pointer to the response (it is always non-NULL). * @param[in] aContext A pointer to application-specific context. * * For the full list of possible values for @p aError, please see `otDnsAddressCallback()`. * */ typedef void (*otDnsBrowseCallback)(otError aError, const otDnsBrowseResponse *aResponse, void *aContext); /** * Provides info for a DNS service instance. * */ typedef struct otDnsServiceInfo { uint32_t mTtl; ///< Service record TTL (in seconds). uint16_t mPort; ///< Service port number. uint16_t mPriority; ///< Service priority. uint16_t mWeight; ///< Service weight. char *mHostNameBuffer; ///< Buffer to output the service host name (can be NULL if not needed). uint16_t mHostNameBufferSize; ///< Size of `mHostNameBuffer`. otIp6Address mHostAddress; ///< The host IPv6 address. Set to all zero if not available. uint32_t mHostAddressTtl; ///< The host address TTL. uint8_t *mTxtData; ///< Buffer to output TXT data (can be NULL if not needed). uint16_t mTxtDataSize; ///< On input, size of `mTxtData` buffer. On output number bytes written. bool mTxtDataTruncated; ///< Indicates if TXT data could not fit in `mTxtDataSize` and was truncated. uint32_t mTxtDataTtl; ///< The TXT data TTL. } otDnsServiceInfo; /** * Sends a DNS browse (service instance enumeration) query for a given service name. * * Is available when `OPENTHREAD_CONFIG_DNS_CLIENT_SERVICE_DISCOVERY_ENABLE` is enabled. * * The @p aConfig can be NULL. In this case the default config (from `otDnsClientGetDefaultConfig()`) will be used as * the config for this query. In a non-NULL @p aConfig, some of the fields can be left unspecified (value zero). The * unspecified fields are then replaced by the values from the default config. * * @param[in] aInstance A pointer to an OpenThread instance. * @param[in] aServiceName The service name to query for (MUST NOT be NULL). * @param[in] aCallback A function pointer that shall be called on response reception or time-out. * @param[in] aContext A pointer to arbitrary context information. * @param[in] aConfig A pointer to the config to use for this query. * * @retval OT_ERROR_NONE Query sent successfully. @p aCallback will be invoked to report the status. * @retval OT_ERROR_NO_BUFS Insufficient buffer to prepare and send query. * */ otError otDnsClientBrowse(otInstance *aInstance, const char *aServiceName, otDnsBrowseCallback aCallback, void *aContext, const otDnsQueryConfig *aConfig); /** * Gets the service name associated with a DNS browse (service instance enumeration) response. * * MUST only be used from `otDnsBrowseCallback`. * * @param[in] aResponse A pointer to the response. * @param[out] aNameBuffer A buffer to char array to output the service name (MUST NOT be NULL). * @param[in] aNameBufferSize The size of @p aNameBuffer. * * @retval OT_ERROR_NONE The service name was read successfully. * @retval OT_ERROR_NO_BUFS The name does not fit in @p aNameBuffer. * */ otError otDnsBrowseResponseGetServiceName(const otDnsBrowseResponse *aResponse, char *aNameBuffer, uint16_t aNameBufferSize); /** * Gets a service instance associated with a DNS browse (service instance enumeration) response. * * MUST only be used from `otDnsBrowseCallback`. * * The response may include multiple service instance records. @p aIndex can be used to iterate through the list. Index * zero gives the first record. When we reach end of the list, `OT_ERROR_NOT_FOUND` is returned. * * Note that this function gets the service instance label and not the full service instance name which is of the form * `..`. * * @param[in] aResponse A pointer to the response. * @param[in] aIndex The service instance record index to retrieve. * @param[out] aLabelBuffer A buffer to char array to output the service instance label (MUST NOT be NULL). * @param[in] aLabelBufferSize The size of @p aLabelBuffer. * * @retval OT_ERROR_NONE The service instance was read successfully. * @retval OT_ERROR_NO_BUFS The name does not fit in @p aNameBuffer. * @retval OT_ERROR_NOT_FOUND No service instance record in @p aResponse at @p aIndex. * @retval OT_ERROR_PARSE Could not parse the records in the @p aResponse. * */ otError otDnsBrowseResponseGetServiceInstance(const otDnsBrowseResponse *aResponse, uint16_t aIndex, char *aLabelBuffer, uint8_t aLabelBufferSize); /** * Gets info for a service instance from a DNS browse (service instance enumeration) response. * * MUST only be used from `otDnsBrowseCallback`. * * A browse DNS response can include SRV, TXT, and AAAA records for the service instances that are enumerated. This is * a SHOULD and not a MUST requirement, and servers/resolvers are not required to provide this. This function attempts * to retrieve this info for a given service instance when available. * * - If no matching SRV record is found in @p aResponse, `OT_ERROR_NOT_FOUND` is returned. In this case, no additional * records (no TXT and/or AAAA) are read. * - If a matching SRV record is found in @p aResponse, @p aServiceInfo is updated and `OT_ERROR_NONE` is returned. * - If no matching TXT record is found in @p aResponse, `mTxtDataSize` in @p aServiceInfo is set to zero. * - If TXT data length is greater than `mTxtDataSize`, it is read partially and `mTxtDataTruncated` is set to true. * - If no matching AAAA record is found in @p aResponse, `mHostAddress is set to all zero or unspecified address. * - If there are multiple AAAA records for the host name in @p aResponse, `mHostAddress` is set to the first one. The * other addresses can be retrieved using `otDnsBrowseResponseGetHostAddress()`. * * @param[in] aResponse A pointer to the response. * @param[in] aInstanceLabel The service instance label (MUST NOT be NULL). * @param[out] aServiceInfo A `ServiceInfo` to output the service instance information (MUST NOT be NULL). * * @retval OT_ERROR_NONE The service instance info was read. @p aServiceInfo is updated. * @retval OT_ERROR_NOT_FOUND Could not find a matching SRV record for @p aInstanceLabel. * @retval OT_ERROR_NO_BUFS The host name and/or TXT data could not fit in the given buffers. * @retval OT_ERROR_PARSE Could not parse the records in the @p aResponse. * */ otError otDnsBrowseResponseGetServiceInfo(const otDnsBrowseResponse *aResponse, const char *aInstanceLabel, otDnsServiceInfo *aServiceInfo); /** * Gets the host IPv6 address from a DNS browse (service instance enumeration) response. * * MUST only be used from `otDnsBrowseCallback`. * * The response can include zero or more IPv6 address records. @p aIndex can be used to iterate through the list of * addresses. Index zero gets the first address and so on. When we reach end of the list, `OT_ERROR_NOT_FOUND` is * returned. * * @param[in] aResponse A pointer to the response. * @param[in] aHostName The host name to get the address (MUST NOT be NULL). * @param[in] aIndex The address record index to retrieve. * @param[out] aAddress A pointer to a IPv6 address to output the address (MUST NOT be NULL). * @param[out] aTtl A pointer to an `uint32_t` to output TTL for the address. It can be NULL if caller does * not want to get the TTL. * * @retval OT_ERROR_NONE The address was read successfully. * @retval OT_ERROR_NOT_FOUND No address record for @p aHostname in @p aResponse at @p aIndex. * @retval OT_ERROR_PARSE Could not parse the records in the @p aResponse. * */ otError otDnsBrowseResponseGetHostAddress(const otDnsBrowseResponse *aResponse, const char *aHostName, uint16_t aIndex, otIp6Address *aAddress, uint32_t *aTtl); /** * An opaque representation of a response to a service instance resolution DNS query. * * Pointers to instance of this type are provided from callback `otDnsAddressCallback`. * */ typedef struct otDnsServiceResponse otDnsServiceResponse; /** * Pointer is called when a DNS response is received for a service instance resolution query. * * Within this callback the user can use `otDnsServiceResponseGet{Item}()` functions along with the @p aResponse * pointer to get more info about the response. * * The @p aResponse pointer can only be used within this callback and after returning from this function it will not * stay valid, so the user MUST NOT retain the @p aResponse pointer for later use. * * @param[in] aError The result of the DNS transaction. * @param[in] aResponse A pointer to the response (it is always non-NULL). * @param[in] aContext A pointer to application-specific context. * * For the full list of possible values for @p aError, please see `otDnsAddressCallback()`. * */ typedef void (*otDnsServiceCallback)(otError aError, const otDnsServiceResponse *aResponse, void *aContext); /** * Starts a DNS service instance resolution for a given service instance. * * Is available when `OPENTHREAD_CONFIG_DNS_CLIENT_SERVICE_DISCOVERY_ENABLE` is enabled. * * The @p aConfig can be NULL. In this case the default config (from `otDnsClientGetDefaultConfig()`) will be used as * the config for this query. In a non-NULL @p aConfig, some of the fields can be left unspecified (value zero). The * unspecified fields are then replaced by the values from the default config. * * The function sends queries for SRV and/or TXT records for the given service instance. The `mServiceMode` field in * `otDnsQueryConfig` determines which records to query (SRV only, TXT only, or both SRV and TXT) and how to perform * the query (together in the same message, separately in parallel, or in optimized mode where client will try in the * same message first and then separately if it fails to get a response). * * The SRV record provides information about service port, priority, and weight along with the host name associated * with the service instance. This function DOES NOT perform address resolution for the host name discovered from SRV * record. The server/resolver may provide AAAA/A record(s) for the host name in the Additional Data section of the * response to SRV/TXT query and this information can be retrieved using `otDnsServiceResponseGetServiceInfo()` in * `otDnsServiceCallback`. Users of this API MUST NOT assume that host address will always be available from * `otDnsServiceResponseGetServiceInfo()`. * * @param[in] aInstance A pointer to an OpenThread instance. * @param[in] aInstanceLabel The service instance label. * @param[in] aServiceName The service name (together with @p aInstanceLabel form full instance name). * @param[in] aCallback A function pointer that shall be called on response reception or time-out. * @param[in] aContext A pointer to arbitrary context information. * @param[in] aConfig A pointer to the config to use for this query. * * @retval OT_ERROR_NONE Query sent successfully. @p aCallback will be invoked to report the status. * @retval OT_ERROR_NO_BUFS Insufficient buffer to prepare and send query. * @retval OT_ERROR_INVALID_ARGS @p aInstanceLabel is NULL. * */ otError otDnsClientResolveService(otInstance *aInstance, const char *aInstanceLabel, const char *aServiceName, otDnsServiceCallback aCallback, void *aContext, const otDnsQueryConfig *aConfig); /** * Starts a DNS service instance resolution for a given service instance, with a potential follow-up * address resolution for the host name discovered for the service instance. * * Is available when `OPENTHREAD_CONFIG_DNS_CLIENT_SERVICE_DISCOVERY_ENABLE` is enabled. * * The @p aConfig can be NULL. In this case the default config (from `otDnsClientGetDefaultConfig()`) will be used as * the config for this query. In a non-NULL @p aConfig, some of the fields can be left unspecified (value zero). The * unspecified fields are then replaced by the values from the default config. This function cannot be used with * `mServiceMode` in DNS config set to `OT_DNS_SERVICE_MODE_TXT` (i.e., querying for TXT record only) and will return * `OT_ERROR_INVALID_ARGS`. * * Behaves similarly to `otDnsClientResolveService()` sending queries for SRV and TXT records. However, * if the server/resolver does not provide AAAA/A records for the host name in the response to SRV query (in the * Additional Data section), it will perform host name resolution (sending an AAAA query) for the discovered host name * from the SRV record. The callback @p aCallback is invoked when responses for all queries are received (i.e., both * service and host address resolutions are finished). * * @param[in] aInstance A pointer to an OpenThread instance. * @param[in] aInstanceLabel The service instance label. * @param[in] aServiceName The service name (together with @p aInstanceLabel form full instance name). * @param[in] aCallback A function pointer that shall be called on response reception or time-out. * @param[in] aContext A pointer to arbitrary context information. * @param[in] aConfig A pointer to the config to use for this query. * * @retval OT_ERROR_NONE Query sent successfully. @p aCallback will be invoked to report the status. * @retval OT_ERROR_NO_BUFS Insufficient buffer to prepare and send query. * @retval OT_ERROR_INVALID_ARGS @p aInstanceLabel is NULL, or @p aConfig is invalid. * */ otError otDnsClientResolveServiceAndHostAddress(otInstance *aInstance, const char *aInstanceLabel, const char *aServiceName, otDnsServiceCallback aCallback, void *aContext, const otDnsQueryConfig *aConfig); /** * Gets the service instance name associated with a DNS service instance resolution response. * * MUST only be used from `otDnsServiceCallback`. * * @param[in] aResponse A pointer to the response. * @param[out] aLabelBuffer A buffer to char array to output the service instance label (MUST NOT be NULL). * @param[in] aLabelBufferSize The size of @p aLabelBuffer. * @param[out] aNameBuffer A buffer to char array to output the rest of service name (can be NULL if user is * not interested in getting the name. * @param[in] aNameBufferSize The size of @p aNameBuffer. * * @retval OT_ERROR_NONE The service name was read successfully. * @retval OT_ERROR_NO_BUFS Either the label or name does not fit in the given buffers. * */ otError otDnsServiceResponseGetServiceName(const otDnsServiceResponse *aResponse, char *aLabelBuffer, uint8_t aLabelBufferSize, char *aNameBuffer, uint16_t aNameBufferSize); /** * Gets info for a service instance from a DNS service instance resolution response. * * MUST only be used from a `otDnsServiceCallback` triggered from `otDnsClientResolveService()` or * `otDnsClientResolveServiceAndHostAddress()`. * * When this is is used from a `otDnsClientResolveService()` callback, the DNS response from server/resolver may * include AAAA records in its Additional Data section for the host name associated with the service instance that is * resolved. This is a SHOULD and not a MUST requirement so servers/resolvers are not required to provide this. This * function attempts to parse AAAA record(s) if included in the response. If it is not included `mHostAddress` is set * to all zeros (unspecified address). To also resolve the host address, user can use the DNS client API function * `otDnsClientResolveServiceAndHostAddress()` which will perform service resolution followed up by a host name * address resolution query (when AAAA records are not provided by server/resolver in the SRV query response). * * - If a matching SRV record is found in @p aResponse, @p aServiceInfo is updated. * - If no matching SRV record is found, `OT_ERROR_NOT_FOUND` is returned unless the query config for this query * used `OT_DNS_SERVICE_MODE_TXT` for `mServiceMode` (meaning the request was only for TXT record). In this case, we * still try to parse the SRV record from Additional Data Section of response (in case server provided the info). * - If no matching TXT record is found in @p aResponse, `mTxtDataSize` in @p aServiceInfo is set to zero. * - If TXT data length is greater than `mTxtDataSize`, it is read partially and `mTxtDataTruncated` is set to true. * - If no matching AAAA record is found in @p aResponse, `mHostAddress is set to all zero or unspecified address. * - If there are multiple AAAA records for the host name in @p aResponse, `mHostAddress` is set to the first one. The * other addresses can be retrieved using `otDnsServiceResponseGetHostAddress()`. * * @param[in] aResponse A pointer to the response. * @param[out] aServiceInfo A `ServiceInfo` to output the service instance information (MUST NOT be NULL). * * @retval OT_ERROR_NONE The service instance info was read. @p aServiceInfo is updated. * @retval OT_ERROR_NOT_FOUND Could not find a required record in @p aResponse. * @retval OT_ERROR_NO_BUFS The host name and/or TXT data could not fit in the given buffers. * @retval OT_ERROR_PARSE Could not parse the records in the @p aResponse. * */ otError otDnsServiceResponseGetServiceInfo(const otDnsServiceResponse *aResponse, otDnsServiceInfo *aServiceInfo); /** * Gets the host IPv6 address from a DNS service instance resolution response. * * MUST only be used from `otDnsServiceCallback`. * * The response can include zero or more IPv6 address records. @p aIndex can be used to iterate through the list of * addresses. Index zero gets the first address and so on. When we reach end of the list, `OT_ERROR_NOT_FOUND` is * returned. * * @param[in] aResponse A pointer to the response. * @param[in] aHostName The host name to get the address (MUST NOT be NULL). * @param[in] aIndex The address record index to retrieve. * @param[out] aAddress A pointer to a IPv6 address to output the address (MUST NOT be NULL). * @param[out] aTtl A pointer to an `uint32_t` to output TTL for the address. It can be NULL if caller does * not want to get the TTL. * * @retval OT_ERROR_NONE The address was read successfully. * @retval OT_ERROR_NOT_FOUND No address record for @p aHostname in @p aResponse at @p aIndex. * @retval OT_ERROR_PARSE Could not parse the records in the @p aResponse. * */ otError otDnsServiceResponseGetHostAddress(const otDnsServiceResponse *aResponse, const char *aHostName, uint16_t aIndex, otIp6Address *aAddress, uint32_t *aTtl); /** * @} * */ #ifdef __cplusplus } // extern "C" #endif #endif // OPENTHREAD_DNS_CLIENT_H_