target = "https://www.rfc-editor.org/rfc/rfc9000#section-17.2.3"

# 17.2.3.  0-RTT
#
# A 0-RTT packet uses long headers with a type value of 0x01, followed
# by the Length and Packet Number fields; see Section 17.2.  The first
# byte contains the Reserved and Packet Number Length bits; see
# Section 17.2.  A 0-RTT packet is used to carry "early" data from the
# client to the server as part of the first flight, prior to handshake
# completion.  As part of the TLS handshake, the server can accept or
# reject this early data.
# 
# See Section 2.3 of [TLS13] for a discussion of 0-RTT data and its
# limitations.
# 
# 0-RTT Packet {
#   Header Form (1) = 1,
#   Fixed Bit (1) = 1,
#   Long Packet Type (2) = 1,
#   Reserved Bits (2),
#   Packet Number Length (2),
#   Version (32),
#   Destination Connection ID Length (8),
#   Destination Connection ID (0..160),
#   Source Connection ID Length (8),
#   Source Connection ID (0..160),
#   Length (i),
#   Packet Number (8..32),
#   Packet Payload (8..),
# }
# 
#                        Figure 16: 0-RTT Packet
# 
# Packet numbers for 0-RTT protected packets use the same space as
# 1-RTT protected packets.
# 
# After a client receives a Retry packet, 0-RTT packets are likely to
# have been lost or discarded by the server.  A client SHOULD attempt
# to resend data in 0-RTT packets after it sends a new Initial packet.
# New packet numbers MUST be used for any new packets that are sent; as
# described in Section 17.2.5.3, reusing packet numbers could
# compromise packet protection.
# 
# A client only receives acknowledgments for its 0-RTT packets once the
# handshake is complete, as defined in Section 4.1.1 of [QUIC-TLS].
# 
# A client MUST NOT send 0-RTT packets once it starts processing 1-RTT
# packets from the server.  This means that 0-RTT packets cannot
# contain any response to frames from 1-RTT packets.  For instance, a
# client cannot send an ACK frame in a 0-RTT packet, because that can
# only acknowledge a 1-RTT packet.  An acknowledgment for a 1-RTT
# packet MUST be carried in a 1-RTT packet.
# 
# A server SHOULD treat a violation of remembered limits
# (Section 7.4.1) as a connection error of an appropriate type (for
# instance, a FLOW_CONTROL_ERROR for exceeding stream data limits).

[[spec]]
level = "SHOULD"
quote = '''
A client SHOULD attempt
to resend data in 0-RTT packets after it sends a new Initial packet.
'''

[[spec]]
level = "MUST"
quote = '''
New packet numbers MUST be used for any new packets that are sent; as
described in Section 17.2.5.3, reusing packet numbers could
compromise packet protection.
'''

[[spec]]
level = "MUST"
quote = '''
A client MUST NOT send 0-RTT packets once it starts processing 1-RTT
packets from the server.
'''

[[spec]]
level = "MUST"
quote = '''
An acknowledgment for a 1-RTT
packet MUST be carried in a 1-RTT packet.
'''

[[spec]]
level = "SHOULD"
quote = '''
A server SHOULD treat a violation of remembered limits
(Section 7.4.1) as a connection error of an appropriate type (for
instance, a FLOW_CONTROL_ERROR for exceeding stream data limits).
'''