Allow RETIRE_CONNECTION_ID to be sent in 0-RTT packets

[t-minzheng]

Description
RFC 9000 12.5. Frames and Number Spaces forbids RETIRE_CONNECTION_ID in 0-RTT packets:

"Note that it is not possible to send the following frames in 0-RTT packets for various reasons: HANDSHAKE_DONE, .. RETIRE_CONNECTION_ID."

The QuicSendWriteFrames function correctly excludes HANDSHAKE_DONE from 0-RTT packets:

msquic/src/core/send.c

Lines 648 to 649 in 31d2b73

	if (Builder->Metadata->Flags.KeyType == QUIC_PACKET_KEY_1_RTT &&
	Send->SendFlags & QUIC_CONN_SEND_FLAG_HANDSHAKE_DONE) {

However, it does not perform a similar check for RETIRE_CONNECTION_ID:

msquic/src/core/send.c

Lines 859 to 895 in 31d2b73

	if ((Send->SendFlags & QUIC_CONN_SEND_FLAG_RETIRE_CONNECTION_ID)) {
	BOOLEAN HasMoreCidsToSend = FALSE;
	BOOLEAN MaxFrameLimitHit = FALSE;
	for (CXPLAT_LIST_ENTRY* Entry = Connection->DestCids.Flink;
	Entry != &Connection->DestCids;
	Entry = Entry->Flink) {
	QUIC_CID_LIST_ENTRY* DestCid =
	CXPLAT_CONTAINING_RECORD(
	Entry,
	QUIC_CID_LIST_ENTRY,
	Link);
	if (!DestCid->CID.NeedsToSend) {
	continue;
	}
	CXPLAT_DBG_ASSERT(DestCid->CID.Retired);
	if (MaxFrameLimitHit) {
	HasMoreCidsToSend = TRUE;
	break;
	}
	QUIC_RETIRE_CONNECTION_ID_EX Frame = {
	DestCid->CID.SequenceNumber
	};
	if (QuicRetireConnectionIDFrameEncode(
	&Frame,
	&Builder->DatagramLength,
	AvailableBufferLength,
	Builder->Datagram->Buffer)) {
	DestCid->CID.NeedsToSend = FALSE;
	Builder->Metadata->Frames[
	Builder->Metadata->FrameCount].RETIRE_CONNECTION_ID.Sequence =
	DestCid->CID.SequenceNumber;
	MaxFrameLimitHit =
	QuicPacketBuilderAddFrame(
	Builder, QUIC_FRAME_RETIRE_CONNECTION_ID, TRUE);

As a result, RETIRE_CONNECTION_ID frames may be incorrectly included in 0-RTT packets, violating the QUIC transport specification.

Suggested Fix

Insert a conditional check in line 859 to restrict the emission of RETIRE_CONNECTION_ID frames to 1-RTT packets only: if (Builder->Metadata->Flags.KeyType == QUIC_PACKET_KEY_1_RTT &&.

[nibanks]

Personality, I'd just add an assert, if anything. As the spec says, it's impossible to send it. The logic for queuing up such a frame doesn't run until you receive a packet, which is after the 0-RTT phase.