[MPTCP] question on MP_CAPABLE v1 handshake

[MPTCP] question on MP_CAPABLE v1 handshake

[Paolo Abeni]

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hi,

while testing the v1 MP_CAPABLE handshake, I stumbled upon the
following scenario:

syn + MP_CAPABLE ->

	<- syn + ack + MP_CAPABLE(sndr key)

ack + MP_CAPABLE(sndr key, rcvr key)

	<- ack + DSS(map,data_ack)

At this point, is the client still supposed to send MP_CAPABLE(sndr
key, rcvr key, data_len)? or should it send a plain DSS? Since it
received a DSS from the peer, the client knows that the MP_CAPABLE
options has been successfully received, but reading 

https://datatracker.ietf.org/doc/draft-ietf-mptcp-rfc6824bis/?include_text=1

from section 3.1.:

"""
   If A does not
   immediately have data to send, it MUST include the MP_CAPABLE on the
   third ACK, but without the additional data parameters.  When A does
   have data to send, it must repeat the sending of the MP_CAPABLE
   option from the third ACK, with additional data parameters.
"""

it looks like the client should always use MP_CAPABLE+data for the
first data packet, is that right?

Thanks,

Paolo