Overall tcp tx buffer size on eth0.
An acquisition device configured as a TCP/IP server on eth0 transfers continuously data through a socket to the receive client.
Before TCP/IP transmission, all sampled data are buffered in a circular queue on the server, so that should the eth0 link be abruply removed, any pending sampled data can be transmitted to the client when the eth0 link is restored.
I need to asses - with a C method -how many bytes surely were not received by the client, when the eth0 disconnection occurs.
I believe the pending bytes number depends on the actual TCP/IP socket buffer size, plus any byte pending on the eth0 adapter driver/hw.
A lightly excess estimate can be acceptable, but not too much...
Thank you for your attention.