ThreadError Client::SendMessage(Message &aMessage, const Ip6::MessageInfo &aMessageInfo,
otCoapResponseHandler aHandler, void *aContext)
{
ThreadError error;
Header header;
RequestMetadata requestMetadata;
Message *storedCopy = NULL;
uint16_t copyLength = 0;
SuccessOrExit(error = header.FromMessage(aMessage));
// Set Message Id if it was not already set.
if (header.GetMessageId() == 0)
{
header.SetMessageId(mMessageId++);
aMessage.Write(0, Header::kMinHeaderLength, header.GetBytes());
}
if (header.IsConfirmable())
{
// Create a copy of entire message and enqueue it.
copyLength = aMessage.GetLength();
}
else if (header.IsNonConfirmable() && header.IsRequest() && (aHandler != NULL))
{
// As we do not retransmit non confirmable messages, create a copy of header only, for token information.
copyLength = header.GetLength();
}
if (copyLength > 0)
{
requestMetadata = RequestMetadata(header.IsConfirmable(), aMessageInfo, aHandler, aContext);
VerifyOrExit((storedCopy = CopyAndEnqueueMessage(aMessage, copyLength, requestMetadata)) != NULL,
error = kThreadError_NoBufs);
}
SuccessOrExit(error = mSocket.SendTo(aMessage, aMessageInfo));
exit:
if (error != kThreadError_None && storedCopy != NULL)
{
DequeueMessage(*storedCopy);
}
return error;
}
void Header::SetDefaultResponseHeader(const Header &aRequestHeader)
{
Init(OT_COAP_TYPE_ACKNOWLEDGMENT, OT_COAP_CODE_CHANGED);
SetMessageId(aRequestHeader.GetMessageId());
SetToken(aRequestHeader.GetToken(), aRequestHeader.GetTokenLength());
}
void Client::HandleUdpReceive(Message &aMessage, const Ip6::MessageInfo &aMessageInfo)
{
Header responseHeader;
Header requestHeader;
RequestMetadata requestMetadata;
Message *message = NULL;
ThreadError error;
SuccessOrExit(error = responseHeader.FromMessage(aMessage));
aMessage.MoveOffset(responseHeader.GetLength());
message = FindRelatedRequest(responseHeader, aMessageInfo, requestHeader, requestMetadata);
if (message == NULL)
{
ExitNow();
}
switch (responseHeader.GetType())
{
case kCoapTypeReset:
if (responseHeader.IsEmpty())
{
FinalizeCoapTransaction(*message, requestMetadata, NULL, NULL, kThreadError_Abort);
}
// Silently ignore non-empty reset messages (RFC 7252, p. 4.2).
break;
case kCoapTypeAcknowledgment:
if (responseHeader.IsEmpty())
{
// Empty acknowledgment.
if (requestMetadata.mConfirmable)
{
requestMetadata.mAcknowledged = true;
requestMetadata.UpdateIn(*message);
}
// Remove the message if response is not expected, otherwise await response.
if (requestMetadata.mResponseHandler == NULL)
{
DequeueMessage(*message);
}
}
else if (responseHeader.IsResponse() && responseHeader.IsTokenEqual(requestHeader))
{
// Piggybacked response.
FinalizeCoapTransaction(*message, requestMetadata, &responseHeader, &aMessage, kThreadError_None);
}
// Silently ignore acknowledgments carrying requests (RFC 7252, p. 4.2)
// or with no token match (RFC 7252, p. 5.3.2)
break;
case kCoapTypeConfirmable:
case kCoapTypeNonConfirmable:
if (responseHeader.IsConfirmable())
{
// Send empty ACK if it is a CON message.
SendEmptyAck(aMessageInfo.GetPeerAddr(), aMessageInfo.mPeerPort, responseHeader.GetMessageId());
}
FinalizeCoapTransaction(*message, requestMetadata, &responseHeader, &aMessage, kThreadError_None);
break;
}
exit:
if (error == kThreadError_None && message == NULL)
{
if (responseHeader.IsConfirmable() || responseHeader.IsNonConfirmable())
{
// Successfully parsed a header but no matching request was found - reject the message by sending reset.
SendReset(aMessageInfo.GetPeerAddr(), aMessageInfo.mPeerPort, responseHeader.GetMessageId());
}
}
}