New frame types PING (0x0B) and PONG (0x0C), each carrying an 8-byte
nonce. Server echoes PING nonce verbatim in PONG. Client sends pings
at random 10-100ms intervals, correlates nonces to measure RTT.
Stats shown live: sent/recv counts, loss %, average latency, jitter
(mean absolute delta of consecutive RTTs). Test button toggles on/off.
Updated both Rust server (echo in main.rs) and C# client (PingTest.cs,
SessionManager routing, MainForm Test button + stats label).
Server reads its hostname via gethostname(2) and includes it as a
length-prefixed UTF-8 string at the start of the MANIFEST payload.
Client displays 'Server: <hostname> — <MAC>' in a label above the
upstream list. Both sides updated for the new MANIFEST format:
[hostname_len:1][hostname:N][entries...]
Protocol version unchanged (still 1); MANIFEST payload layout change
is backward-incompatible but both sides ship together.
Ethernet pads frames to 60 bytes minimum; without an explicit length
field the receiver cannot distinguish real payload from zero padding
(e.g. a 6-byte DISCOVER becomes 46 bytes after padding, failing the
'payload must be empty' check).
Header is now 8 bytes: [ver:1][type:1][session_id:4][payload_len:2]
(both multi-byte fields big-endian). The receiver slices exactly
payload_len bytes and ignores trailing padding.
Updated PROTOCOL.md, Rust frame.rs, and C# Frame.cs.