60 lines
1.4 KiB
Go
60 lines
1.4 KiB
Go
package udp
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import (
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"io"
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"net"
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"github.com/rs/zerolog/log"
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)
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// Proxy is a reverse-proxy implementation of the Handler interface.
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type Proxy struct {
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// TODO: maybe optimize by pre-resolving it at proxy creation time
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target string
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}
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// NewProxy creates a new Proxy.
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func NewProxy(address string) (*Proxy, error) {
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return &Proxy{target: address}, nil
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}
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// ServeUDP implements the Handler interface.
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func (p *Proxy) ServeUDP(conn *Conn) {
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log.Debug().Msgf("Handling connection from %s to %s", conn.rAddr, p.target)
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// needed because of e.g. server.trackedConnection
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defer conn.Close()
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connBackend, err := net.Dial("udp", p.target)
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if err != nil {
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log.Error().Err(err).Msg("Error while connecting to backend")
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return
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}
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// maybe not needed, but just in case
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defer connBackend.Close()
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errChan := make(chan error)
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go connCopy(conn, connBackend, errChan)
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go connCopy(connBackend, conn, errChan)
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err = <-errChan
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if err != nil {
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log.Error().Err(err).Msg("Error while serving UDP")
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}
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<-errChan
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}
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func connCopy(dst io.WriteCloser, src io.Reader, errCh chan error) {
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// The buffer is initialized to the maximum UDP datagram size,
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// to make sure that the whole UDP datagram is read or written atomically (no data is discarded).
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buffer := make([]byte, maxDatagramSize)
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_, err := io.CopyBuffer(dst, src, buffer)
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errCh <- err
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if err := dst.Close(); err != nil {
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log.Debug().Err(err).Msg("Error while terminating connection")
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}
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}
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