86 lines
1.5 KiB
Go
86 lines
1.5 KiB
Go
package utils
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import (
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"fmt"
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"net"
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"github.com/vmihailenco/msgpack/v5"
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)
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type UDPPayload struct {
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MagicNumber int `msgpack:"magicNumber"`
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Data string `msgpack:"data"`
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}
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const (
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BUFFER_SIZE int = 1024
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MAGIC_NUMBER int = 114514
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)
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func ListenUDP(
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port string,
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doneCh chan struct{},
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) (string, error) {
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addr, err := net.ResolveUDPAddr("udp", ":"+port)
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if err != nil {
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return "", fmt.Errorf("failed to resolve address, %w", err)
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}
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conn, err := net.ListenUDP("udp", addr)
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if err != nil {
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return "", fmt.Errorf("failed to listen on addr '%v', %w", addr, err)
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}
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defer conn.Close()
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dataCh := make(chan string)
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go func() {
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for {
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buffer := make([]byte, BUFFER_SIZE)
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n, _, err := conn.ReadFromUDP(buffer)
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if err != nil {
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continue
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}
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var payload UDPPayload
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err = msgpack.Unmarshal(buffer[:n], &payload)
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if err == nil && payload.MagicNumber == MAGIC_NUMBER {
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dataCh <- payload.Data
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return
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}
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}
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}()
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select {
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case <-doneCh:
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return "", nil
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case data := <-dataCh:
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return data, nil
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}
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return "", fmt.Errorf("failed to receive data")
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}
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func SendPayload(endpoint, data string) error {
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conn, err := net.Dial("udp", endpoint)
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if err != nil {
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return fmt.Errorf("failed to dial endpoint, %w", err)
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}
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defer conn.Close()
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b, err := msgpack.Marshal(UDPPayload{
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MagicNumber: MAGIC_NUMBER,
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Data: data,
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})
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if err != nil {
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return fmt.Errorf("failed to marshal payload, %w", err)
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}
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_, err = conn.Write(b)
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if err != nil {
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return fmt.Errorf("failed to send payload, %w", err)
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}
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return nil
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}
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