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| author | Christoph Paasch <cpaasch@apple.com> | 2020-05-14 08:53:03 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-05-16 13:51:10 -0700 |
| commit | a0c1d0eafd1ef1ada3b588ea205e5bc37ae0d8d9 (patch) | |
| tree | 9e6c4e1406a00559b1dd4ef04cf502d65e5cb3e7 /include | |
| parent | 9efd6a3cecdde984d67e63d17fe6af53c7c50968 (diff) | |
| download | linux-a0c1d0eafd1ef1ada3b588ea205e5bc37ae0d8d9.tar.bz2 | |
mptcp: Use 32-bit DATA_ACK when possible
RFC8684 allows to send 32-bit DATA_ACKs as long as the peer is not
sending 64-bit data-sequence numbers. The 64-bit DSN is only there for
extreme scenarios when a very high throughput subflow is combined with a
long-RTT subflow such that the high-throughput subflow wraps around the
32-bit sequence number space within an RTT of the high-RTT subflow.
It is thus a rare scenario and we should try to use the 32-bit DATA_ACK
instead as long as possible. It allows to reduce the TCP-option overhead
by 4 bytes, thus makes space for an additional SACK-block. It also makes
tcpdumps much easier to read when the DSN and DATA_ACK are both either
32 or 64-bit.
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/mptcp.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/net/mptcp.h b/include/net/mptcp.h index c4a6ef4ba35b..46d0487d2b22 100644 --- a/include/net/mptcp.h +++ b/include/net/mptcp.h @@ -16,7 +16,10 @@ struct seq_file; /* MPTCP sk_buff extension data */ struct mptcp_ext { - u64 data_ack; + union { + u64 data_ack; + u32 data_ack32; + }; u64 data_seq; u32 subflow_seq; u16 data_len; |