97 lines
2.0 KiB
Go
97 lines
2.0 KiB
Go
package relaysvc
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import (
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"context"
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"sync"
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"github.com/libp2p/go-libp2p/core/event"
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"github.com/libp2p/go-libp2p/core/host"
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"github.com/libp2p/go-libp2p/core/network"
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"github.com/libp2p/go-libp2p/p2p/host/eventbus"
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relayv2 "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/relay"
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)
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type RelayManager struct {
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host host.Host
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mutex sync.Mutex
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relay *relayv2.Relay
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opts []relayv2.Option
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refCount sync.WaitGroup
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ctxCancel context.CancelFunc
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}
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func NewRelayManager(host host.Host, opts ...relayv2.Option) *RelayManager {
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ctx, cancel := context.WithCancel(context.Background())
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m := &RelayManager{
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host: host,
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opts: opts,
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ctxCancel: cancel,
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}
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m.refCount.Add(1)
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go m.background(ctx)
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return m
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}
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func (m *RelayManager) background(ctx context.Context) {
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defer m.refCount.Done()
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defer func() {
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m.mutex.Lock()
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if m.relay != nil {
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m.relay.Close()
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}
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m.mutex.Unlock()
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}()
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subReachability, _ := m.host.EventBus().Subscribe(new(event.EvtLocalReachabilityChanged), eventbus.Name("relaysvc"))
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defer subReachability.Close()
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for {
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select {
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case <-ctx.Done():
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return
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case ev, ok := <-subReachability.Out():
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if !ok {
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return
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}
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if err := m.reachabilityChanged(ev.(event.EvtLocalReachabilityChanged).Reachability); err != nil {
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return
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}
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}
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}
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}
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func (m *RelayManager) reachabilityChanged(r network.Reachability) error {
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switch r {
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case network.ReachabilityPublic:
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m.mutex.Lock()
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defer m.mutex.Unlock()
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// This could happen if two consecutive EvtLocalReachabilityChanged report the same reachability.
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// This shouldn't happen, but it's safer to double-check.
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if m.relay != nil {
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return nil
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}
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relay, err := relayv2.New(m.host, m.opts...)
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if err != nil {
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return err
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}
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m.relay = relay
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default:
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m.mutex.Lock()
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defer m.mutex.Unlock()
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if m.relay != nil {
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err := m.relay.Close()
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m.relay = nil
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return err
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}
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}
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return nil
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}
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func (m *RelayManager) Close() error {
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m.ctxCancel()
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m.refCount.Wait()
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return nil
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}
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