This module includes functions that control DNS communication.

Classes
struct	otDnsQuery
	This structure implements DNS Query parameters.

Macros
#define	OT_DNS_MAX_HOSTNAME_LENGTH 62
	Maximum allowed hostname length (maximum label size - 1 for compression).

#define	OT_DNS_DEFAULT_SERVER_IP "2001:4860:4860::8888"
	Defines default DNS Server address - Google DNS.

#define	OT_DNS_DEFAULT_SERVER_PORT 53
	Defines default DNS Server port.

Typedefs
typedef struct otDnsQuery	otDnsQuery
	This structure implements DNS Query parameters.

typedef void(*	otDnsResponseHandler) (void aContext, const char aHostname, const otIp6Address *aAddress, uint32_t aTtl, otError aResult)
	This function pointer is called when a DNS response is received.

Functions
otError	otDnsClientQuery (otInstance aInstance, const otDnsQuery aQuery, otDnsResponseHandler aHandler, void *aContext)
	This function sends a DNS query for AAAA (IPv6) record.

Detailed Description

This module includes functions that control DNS communication.

Typedef Documentation

typedef void(* otDnsResponseHandler) (void *aContext, const char *aHostname, const otIp6Address *aAddress, uint32_t aTtl, otError aResult)

This function pointer is called when a DNS response is received.

Parameters

[in]	`aContext`	A pointer to application-specific context.
[in]	`aHostname`	Identifies hostname related with DNS response.
[in]	`aAddress`	A pointer to the IPv6 address received in DNS response. May be null.
[in]	`aTtl`	Specifies the maximum time in seconds that the resource record may be cached.
[in]	`aResult`	A result of the DNS transaction.

Return values

`OT_ERROR_NONE`	A response was received successfully and IPv6 address is provided in `aAddress`.
`OT_ERROR_ABORT`	A DNS transaction was aborted by stack.
`OT_ERROR_RESPONSE_TIMEOUT`	No DNS response has been received within timeout.
`OT_ERROR_NOT_FOUND`	A response was received but no IPv6 address has been found.
`OT_ERROR_FAILED`	A response was received but status code is different than success.

This function sends a DNS query for AAAA (IPv6) record.

This function is available only if feature OPENTHREAD_CONFIG_DNS_CLIENT_ENABLE is enabled.

Parameters

[in]	`aInstance`	A pointer to an OpenThread instance.
[in]	`aQuery`	A pointer to specify DNS query parameters.
[in]	`aHandler`	A function pointer that shall be called on response reception or time-out.
[in]	`aContext`	A pointer to arbitrary context information.