43 lines
766 B
Go
43 lines
766 B
Go
package discovery
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import (
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"context"
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"net"
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"strings"
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"time"
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)
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func Serve(ctx context.Context, port int, grpcAddr string) error {
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conn, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: port})
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if err != nil {
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return err
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}
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defer conn.Close()
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buf := make([]byte, 256)
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for {
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if err := conn.SetReadDeadline(time.Now().Add(time.Second)); err != nil {
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return err
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}
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n, remote, err := conn.ReadFromUDP(buf)
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if err != nil {
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if ne, ok := err.(net.Error); ok && ne.Timeout() {
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select {
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case <-ctx.Done():
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return nil
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default:
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continue
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}
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}
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return err
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}
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if strings.TrimSpace(string(buf[:n])) != requestMagic {
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continue
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}
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_, _ = conn.WriteToUDP([]byte(responsePrefix+grpcAddr), remote)
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}
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}
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