otPlatDnssdKey struct

Registers or updates a key record on mDNS module. The fields in @p aKey follow these rules: - If the key is associated with a host entry, the `mName` field specifies the host name and the `mServiceType` MUST be NULL. - If the key is associated with a service entry, the `mName` filed specifies the service instance label (always treated as a single label) and the `mServiceType` filed specifies the service type (e.g., "_tst._udp"). In this case the DNS name for key record is `.`. - The `mKeyData` field contains the key record's data with `mKeyDataLength` as its length in byes. - The `mTtl` specifies the TTL if non-zero. If zero, the mDNS module will use the default TTL of 120 seconds. - Other fields in @p aKey structure are ignored in an `otMdnsRegisterKey()` call. This function can be called again for the same name to updated a previously registered key entry, for example, to change the key data or TTL. Regarding the invocation of the @p aCallback, this function behaves in the same way as described in `otMdnsRegisterHost()`.

Unregisters a key record on mDNS. The fields in @p aKey follow these rules: - If the key is associated with a host entry, the `mName` field specifies the host name and the `mServiceType` MUST be NULL. - If the key is associated with a service entry, the `mName` filed specifies the service instance label (always treated as a single label) and the `mServiceType` filed specifies the service type (e.g., "_tst._udp"). In this case the DNS name for key record is `.`. - Other fields in @p aKey structure are ignored in an `otMdnsUnregisterKey()` call. If there is no previously registered key with the same name, no action is performed. If there is a previously registered key with the same name, the mDNS module will send "goodbye" announcements for the key record.

Registers or updates a key record on the infrastructure network's DNS-SD module. The @p aKey and all its contained information (strings and arrays) are only valid during this call. The platform MUST save a copy of the information if it wants to retain the information after returning from this function. The fields in @p aKey follow these rules: - If the key is associated with a host, `mName` field specifies the host name and `mServiceType` will be NULL. - If the key is associated with a service, `mName` field specifies the service instance label and `mServiceType` field specifies the service type. In this case the DNS name for key record is `{mName}.{mServiceTye}`. - The `mKeyData` field contains the key record's data with `mKeyDataLength` as its length in byes. It is never NULL. - The `mClass` fields specifies the resource record class to use when registering key record. - The `mTtl` field specifies the TTL if non-zero. If zero, the platform can choose the TTL to use. - The `mInfraIfIndex` field, if non-zero, specifies the infrastructure network interface index to use for this request. If zero, the platform implementation can decided the interface. Regarding the invocation of the @p aCallback and the reuse of the @p aRequestId, this function follows the same rules as described in `otPlatDnssdRegisterService()`. The OpenThread stack will not register the same key (with no changes) that was registered successfully earlier. Therefore, the platform implementation does not need to check for duplicate/same name and can assume that calls to this function are either registering a new key or changing the key data in a previously registered one. As a result, these changes always need to be synced on the infrastructure DNS-SD module.

Unregisters a key record on the infrastructure network's DNS-SD module. The @p aKey and all its contained information (strings and arrays) are only valid during this call. The platform MUST save a copy of the information if it wants to retain the information after returning from this function. The fields in @p aKey follow these rules: - If the key is associated with a host, `mName` field specifies the host name and `mServiceType` will be NULL. - If the key is associated with a service, `mName` field specifies the service instance label and `mServiceType` field specifies the service type. In this case the DNS name for key record is `{mName}.{mServiceTye}`. - The `mInfraIfIndex` field, if non-zero, specifies the infrastructure network interface index to use for this request. If zero, the platform implementation can decided the interface. - The rest of the fields in @p aKey structure MUST be ignored in `otPlatDnssdUnregisterKey()` call and may be set to zero by the OpenThread stack. Regarding the invocation of the @p aCallback and the reuse of the @p aRequestId, this function follows the same rules as described in `otPlatDnssdRegisterService()`. The OpenThread stack may request the unregistration of a key that was not previously registered, and the platform implementation MUST handle this case. In such a case, the platform can use either `OT_ERROR_NOT_FOUND` to indicate that there was no such registration, or `OT_ERROR_NONE` when invoking the @p aCallback function. the OpenThread stack will handle either case correctly.

Iterates over registered key entries. Requires `OPENTHREAD_CONFIG_MULTICAST_DNS_ENTRY_ITERATION_API_ENABLE`. On success, @p aKey is populated with information about the next key. Pointers within the `otMdnsKey` structure (like `mName`) remain valid until the next call to any OpenThread stack's public or platform API/callback.