Struct TcpConnectionTracker 

pub struct TcpConnectionTracker { /* private fields */ }

Tracks TCP connections between guest and proxy tasks.

Each guest TCP connection maps to a smoltcp socket and a pair of channels connecting it to a tokio proxy task. The tracker handles:

• Socket creation — on SYN detection, before smoltcp processes the frame.
• Data relay — shuttles bytes between smoltcp sockets and channels.
• Lifecycle detection — identifies newly-established connections for proxy spawning.
• Cleanup — removes closed sockets from the socket set.

Implementations

impl TcpConnectionTracker

pub fn new(max_tcp_connections: Option<NonZeroUsize>) -> Self

Create a new tracker with the given connection limit.

pub fn has_socket_for(&self, src: &SocketAddr, dst: &SocketAddr) -> bool

Returns true if a tracked socket already exists for this exact connection (same source AND destination). O(1) via HashSet lookup.

pub fn create_tcp_socket( &mut self, src: SocketAddr, dst: SocketAddr, sockets: &mut SocketSet<'_>, ) -> bool

Create a smoltcp TCP socket for an incoming SYN and register it.

The socket is put into LISTEN state on the destination IP + port so smoltcp will complete the three-way handshake when it processes the SYN frame. Binding to the specific destination IP (not just port) prevents socket dispatch ambiguity when multiple connections target different IPs on the same port.

Returns false if at max_tcp_connections limit.

pub fn relay_data(&mut self, sockets: &mut SocketSet<'_>)

Relay data between smoltcp sockets and proxy task channels.

For each connection with a spawned proxy:

• Reads data from the smoltcp socket and sends it to the proxy channel.
• Receives data from the proxy channel and writes it to the smoltcp socket.

pub fn take_new_connections( &mut self, sockets: &mut SocketSet<'_>, ) -> Vec<NewConnection>

Collect newly-established connections that need proxy tasks.

Returns a list of NewConnection structs containing the channel ends for the proxy task. The poll loop is responsible for spawning the task.

pub fn trace_stats(&self, sockets: &SocketSet<'_>)

Record bounded-cardinality diagnostics once per maintenance interval.

pub fn cleanup_closed(&mut self, sockets: &mut SocketSet<'_>)

Remove closed connections and their sockets.

Idle listeners represent failed/reset SYNs: this tracker never owns persistent listening sockets. Closed sockets with a remote endpoint still owe the guest an RST and must survive until smoltcp emits it. TIME_WAIT remains intact to reject delayed duplicate segments.