BUG/MINOR: quic: Do not resend already acked frames

Some frames are marked as already acknowledged from duplicated packets
whose the original packet has been acknowledged. There is no need
to resend such packets or frames.

Implement qc_pkt_with_only_acked_frms() to detect packet with only
already acknowledged frames inside and use it from qc_prep_fast_retrans()
which selects the packet to be retransmitted.

Must be backported to 2.6 and 2.7.
1 file changed