DNS - Platform

This module includes the platform abstraction for sending recursive DNS query to upstream DNS servers.

Summary

Typedefs
`otPlatDnsUpstreamQuery`	typedef `struct otPlatDnsUpstreamQuery` This opaque type represents an upstream DNS query transaction.

Functions
`otPlatDnsCancelUpstreamQuery(otInstance aInstance, otPlatDnsUpstreamQuery aTxn)`	`void` Cancels a transaction of upstream query.
`otPlatDnsStartUpstreamQuery(otInstance aInstance, otPlatDnsUpstreamQuery aTxn, const otMessage *aQuery)`	`void` Starts an upstream query transaction.
`otPlatDnsUpstreamQueryDone(otInstance aInstance, otPlatDnsUpstreamQuery aTxn, otMessage *aResponse)`	`void` The platform calls this function to finish DNS query.

Typedefs

otPlatDnsUpstreamQuery

struct otPlatDnsUpstreamQuery otPlatDnsUpstreamQuery

This opaque type represents an upstream DNS query transaction.

Functions

otPlatDnsCancelUpstreamQuery

void otPlatDnsCancelUpstreamQuery(
  otInstance *aInstance,
  otPlatDnsUpstreamQuery *aTxn
)

Cancels a transaction of upstream query.

The platform must call otPlatDnsUpstreamQueryDone to release the resources.

Details

Parameters

`[in] aInstance`	The OpenThread instance structure.
`[in] aTxn`	A pointer to the opaque DNS query transaction object.

otPlatDnsStartUpstreamQuery

void otPlatDnsStartUpstreamQuery(
  otInstance *aInstance,
  otPlatDnsUpstreamQuery *aTxn,
  const otMessage *aQuery
)

Starts an upstream query transaction.

In success case (and errors represented by DNS protocol messages), the platform is expected to call otPlatDnsUpstreamQueryDone.
The OpenThread core may cancel a (possibly timeout) query transaction by calling otPlatDnsCancelUpstreamQuery, the platform must not call otPlatDnsUpstreamQueryDone on a cancelled transaction.

Details

Parameters

`[in] aInstance`	The OpenThread instance structure.
`[in] aTxn`	A pointer to the opaque DNS query transaction object.
`[in] aQuery`	A message buffer of the DNS payload that should be sent to upstream DNS server.

otPlatDnsUpstreamQueryDone

void otPlatDnsUpstreamQueryDone(
  otInstance *aInstance,
  otPlatDnsUpstreamQuery *aTxn,
  otMessage *aResponse
)

The platform calls this function to finish DNS query.

The transaction will be released, so the platform must not call on the same transaction twice. This function passes the ownership of aResponse to OpenThread stack.

Platform can pass a nullptr to close a transaction without a response.

Details

Parameters

`[in] aInstance`	The OpenThread instance structure.
`[in] aTxn`	A pointer to the opaque DNS query transaction object.
`[in] aResponse`	A message buffer of the DNS response payload or `nullptr` to close a transaction without a response.

Resources

OpenThread API Reference topics originate from the source code, available on GitHub. For more information, or to contribute to our documentation, refer to Resources.