WIP

peer/on_hub.go

@@ -0,0 +1,115 @@
+package peer
+
+import (
+	"log"
+	"net/netip"
+
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+
+	"vppn/peer/control"
+)
+
+func (a *App) onAddPeer(p HubPeer) {
+	if _, exists := a.peersByKey[p.PubKey]; exists {
+		a.onRemovePeer(p.PubKey)
+	}
+
+	peer := &Peer{
+		PubKey:    p.PubKey,
+		VPNIP:     p.VPNIP,
+		IsRelay:   p.IsRelay,
+		IsPublic:  p.IsPublic,
+		Endpoint4: p.EndpointV4,
+		Endpoint6: p.EndpointV6,
+		Role:      roleFor(a.isPublic, a.vpnIP, p),
+		State:     StateRelayed,
+	}
+
+	endpoint := peer.PreferredEndpoint()
+	if peer.IsPublic && !endpoint.IsValid() {
+		// The peer is misconfigured.
+		// TODO: Log here.
+		return
+	}
+
+	a.peersByKey[p.PubKey] = peer
+	a.peersByIP[peer.VPNIP] = peer
+
+	if !peer.IsPublic {
+		return
+	}
+
+	peer.WGEndpoint = endpoint
+	peer.State = StateDirect
+	a.devAddDirect(peer, endpoint)
+}
+
+func (a *App) onRemovePeer(key wgtypes.Key) {
+	peer, exists := a.peersByKey[key]
+	if !exists {
+		return
+	}
+	a.devRemove(peer)
+	delete(a.peersByKey, key)
+	delete(a.peersByIP, peer.VPNIP)
+
+	if peer == a.relay {
+		a.relay = nil
+		a.switchActiveRelay()
+	}
+}
+
+// switchActiveRelay promotes the lowest-latency relay peer to active.
+func (a *App) switchActiveRelay() {
+	if a.relay != nil {
+		a.devAddDirect(a.relay, a.relay.WGEndpoint)
+		a.relay = nil
+	}
+
+	var best *Peer
+	for _, p := range a.peersByKey {
+		if !p.CanRelay() {
+			continue
+		}
+
+		if best == nil || betterRelay(p, best) {
+			best = p
+		}
+	}
+	if best == nil {
+		log.Printf("no relay available")
+		return
+	}
+
+	a.devSetRelay(best, best.WGEndpoint)
+	a.relay = best
+}
+
+// betterRelay reports whether a is a better relay candidate than b.
+// Prefers lower RTT; treats zero RTT (no measurement yet) as worst case.
+func betterRelay(a, b *Peer) bool {
+	if a.RTT == 0 {
+		return false
+	}
+	if b.RTT == 0 {
+		return true
+	}
+	return a.RTT < b.RTT
+}
+
+func preferredEndpoint(v4, v6 netip.AddrPort) netip.AddrPort {
+	if v4.IsValid() {
+		return v4
+	}
+	return v6
+}
+
+func roleFor(selfIsPublic bool, selfIP netip.Addr, p HubPeer) control.Role {
+	if !selfIsPublic && p.IsPublic {
+		return control.Client
+	}
+	if selfIsPublic && !p.IsPublic {
+		return control.Server
+	}
+	return control.RoleFor(selfIP, p.VPNIP)
+}