target = "https://www.rfc-editor.org/rfc/rfc9000#section-7.2"

# 7.2.  Negotiating Connection IDs
#
# A connection ID is used to ensure consistent routing of packets, as
# described in Section 5.1.  The long header contains two connection
# IDs: the Destination Connection ID is chosen by the recipient of the
# packet and is used to provide consistent routing; the Source
# Connection ID is used to set the Destination Connection ID used by
# the peer.
# 
# During the handshake, packets with the long header (Section 17.2) are
# used to establish the connection IDs used by both endpoints.  Each
# endpoint uses the Source Connection ID field to specify the
# connection ID that is used in the Destination Connection ID field of
# packets being sent to them.  After processing the first Initial
# packet, each endpoint sets the Destination Connection ID field in
# subsequent packets it sends to the value of the Source Connection ID
# field that it received.
# 
# When an Initial packet is sent by a client that has not previously
# received an Initial or Retry packet from the server, the client
# populates the Destination Connection ID field with an unpredictable
# value.  This Destination Connection ID MUST be at least 8 bytes in
# length.  Until a packet is received from the server, the client MUST
# use the same Destination Connection ID value on all packets in this
# connection.
# 
# The Destination Connection ID field from the first Initial packet
# sent by a client is used to determine packet protection keys for
# Initial packets.  These keys change after receiving a Retry packet;
# see Section 5.2 of [QUIC-TLS].
# 
# The client populates the Source Connection ID field with a value of
# its choosing and sets the Source Connection ID Length field to
# indicate the length.
# 
# 0-RTT packets in the first flight use the same Destination Connection
# ID and Source Connection ID values as the client's first Initial
# packet.
# 
# Upon first receiving an Initial or Retry packet from the server, the
# client uses the Source Connection ID supplied by the server as the
# Destination Connection ID for subsequent packets, including any 0-RTT
# packets.  This means that a client might have to change the
# connection ID it sets in the Destination Connection ID field twice
# during connection establishment: once in response to a Retry packet
# and once in response to an Initial packet from the server.  Once a
# client has received a valid Initial packet from the server, it MUST
# discard any subsequent packet it receives on that connection with a
# different Source Connection ID.
# 
# A client MUST change the Destination Connection ID it uses for
# sending packets in response to only the first received Initial or
# Retry packet.  A server MUST set the Destination Connection ID it
# uses for sending packets based on the first received Initial packet.
# Any further changes to the Destination Connection ID are only
# permitted if the values are taken from NEW_CONNECTION_ID frames; if
# subsequent Initial packets include a different Source Connection ID,
# they MUST be discarded.  This avoids unpredictable outcomes that
# might otherwise result from stateless processing of multiple Initial
# packets with different Source Connection IDs.
# 
# The Destination Connection ID that an endpoint sends can change over
# the lifetime of a connection, especially in response to connection
# migration (Section 9); see Section 5.1.1 for details.

[[spec]]
level = "MUST"
quote = '''
This Destination Connection ID MUST be at least 8 bytes in
length.
'''

[[spec]]
level = "MUST"
quote = '''
Until a packet is received from the server, the client MUST
use the same Destination Connection ID value on all packets in this
connection.
'''

[[spec]]
level = "MUST"
quote = '''
Once a
client has received a valid Initial packet from the server, it MUST
discard any subsequent packet it receives on that connection with a
different Source Connection ID.
'''

[[spec]]
level = "MUST"
quote = '''
A client MUST change the Destination Connection ID it uses for
sending packets in response to only the first received Initial or
Retry packet.
'''

[[spec]]
level = "MUST"
quote = '''
A server MUST set the Destination Connection ID it
uses for sending packets based on the first received Initial packet.
'''

[[spec]]
level = "MUST"
quote = '''
Any further changes to the Destination Connection ID are only
permitted if the values are taken from NEW_CONNECTION_ID frames; if
subsequent Initial packets include a different Source Connection ID,
they MUST be discarded.
'''