Files
netbird/client/iface/wgproxy/proxy.go
Zoltan Papp e8d301fdc9 [client] Fix/pkg loss (#3338)
The Relayed connection setup is optimistic. It does not have any confirmation of an established end-to-end connection. Peers start sending WireGuard handshake packets immediately after the successful offer-answer handshake.
Meanwhile, for successful P2P connection negotiation, we change the WireGuard endpoint address, but this change does not trigger new handshake initiation. Because the peer switched from Relayed connection to P2P, the packets from the Relay server are dropped and must wait for the next WireGuard handshake via P2P.

To avoid this scenario, the relayed WireGuard proxy no longer drops the packets. Instead, it rewrites the source address to the new P2P endpoint and continues forwarding the packets.

We still have one corner case: if the Relayed server negotiation chooses a server that has not been used before. In this case, one side of the peer connection will be slower to reach the Relay server, and the Relay server will drop the handshake packet.

If everything goes well we should see exactly 5 seconds improvements between the WireGuard configuration time and the handshake time.
2025-09-30 15:31:18 +02:00

22 lines
862 B
Go

package wgproxy
import (
"context"
"net"
)
// Proxy is a transfer layer between the relayed connection and the WireGuard
type Proxy interface {
AddTurnConn(ctx context.Context, endpoint *net.UDPAddr, remoteConn net.Conn) error
EndpointAddr() *net.UDPAddr // EndpointAddr returns the address of the WireGuard peer endpoint
Work() // Work start or resume the proxy
Pause() // Pause to forward the packages from remote connection to WireGuard. The opposite way still works.
//RedirectAs resume the forwarding the packages from relayed connection to WireGuard interface if it was paused
//and rewrite the src address to the endpoint address.
//With this logic can avoid the package loss from relayed connections.
RedirectAs(endpoint *net.UDPAddr)
CloseConn() error
SetDisconnectListener(disconnected func())
}