WIP

peer/on_ping.go

@@ -0,0 +1,66 @@
+package peer
+
+import (
+	"net/netip"
+	"time"
+
+	"vppn/peer/control"
+)
+
+func (a *App) onPing(e PingEvent) {
+	peer, ok := a.peersByIP[e.srcVPNIP]
+	if !ok {
+		// TODO: Log here.
+		return
+	}
+
+	now := time.Now()
+	peer.LastPing = now
+	peer.Up = true
+
+	// If we're the server, respond.
+	if peer.Role == control.Server {
+		a.sendPing(peer, e.ping.ID, e.ping.PingTS)
+	}
+
+	// Compute RTT from server echo.
+	if peer.Role == control.Client {
+		peer.RTT = now.Sub(time.Unix(0, e.ping.PingTS))
+	}
+
+	// If we're public, nothing more to do.
+	if a.isPublic {
+		return
+	}
+
+	// We can only learn our own endpoint from directly-connected peers — Dst
+	// is the sender's observation of our WG handshake source.
+	if peer.State == StateDirect {
+		if dst := e.ping.Dst; dst.IsValid() {
+			if dst.Addr().Is4() {
+				a.selfV4 = dst
+			} else {
+				a.selfV6 = dst
+			}
+		}
+		return
+	}
+
+	a.addProbe(peer, e.ping.SrcV4, e.ping.SrcV6)
+}
+
+func (a *App) addProbe(peer *Peer, v4, v6 netip.AddrPort) {
+	endpoint := preferredEndpoint(v4, v6)
+	if !endpoint.IsValid() || endpoint == peer.WGEndpoint {
+		return
+	}
+
+	peer.Endpoint4 = v4
+	peer.Endpoint6 = v6
+	peer.WGEndpoint = endpoint
+
+	if peer.State == StateRelayed {
+		peer.State = StateProbing
+	}
+	a.devAddProbe(peer, endpoint)
+}