50 lines
1.3 KiB
Go
50 lines
1.3 KiB
Go
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package main
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import (
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"errors"
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"net"
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"time"
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"github.com/jedisct1/dlog"
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)
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func NetProbe(address string, timeout int) error {
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if len(address) <= 0 || timeout <= 0 {
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return nil
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}
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remoteUDPAddr, err := net.ResolveUDPAddr("udp", address)
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if err != nil {
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return err
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}
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retried := false
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if timeout < 0 {
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timeout = MaxTimeout
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} else {
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timeout = Max(MaxTimeout, timeout)
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}
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for tries := timeout; tries > 0; tries-- {
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pc, err := net.DialUDP("udp", nil, remoteUDPAddr)
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if err == nil {
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// Write at least 1 byte. This ensures that sockets are ready to use for writing.
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// Windows specific: during the system startup, sockets can be created but the underlying buffers may not be setup yet. If this is the case
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// Write fails with WSAENOBUFS: "An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full"
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_, err = pc.Write([]byte{0})
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}
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if err != nil {
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if !retried {
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retried = true
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dlog.Notice("Network not available yet -- waiting...")
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}
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dlog.Debug(err)
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time.Sleep(1 * time.Second)
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continue
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}
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pc.Close()
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dlog.Notice("Network connectivity detected")
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return nil
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}
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es := "Timeout while waiting for network connectivity"
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dlog.Error(es)
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return errors.New(es)
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}
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