94 lines
1.7 KiB
Go
94 lines
1.7 KiB
Go
package main
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import (
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"encoding/binary"
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"encoding/json"
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"fmt"
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"io"
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"log"
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"net"
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)
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type Message struct {
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Body string `json:"body"`
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}
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const MSG_SIZE_LIMIT = 1000 * 1000 // Unclear if 1MiB or 1MB, using lower bound
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const LISTEN_INTERFACE = ":30501"
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func main() {
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log.Println("Listening on", LISTEN_INTERFACE)
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l, err := net.Listen("tcp", LISTEN_INTERFACE)
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if err != nil {
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log.Fatal(err)
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}
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defer l.Close()
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msg_pipe := make(chan string)
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// Output routine
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go func() {
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for {
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msg, err := json.Marshal(Message{<-msg_pipe})
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if err != nil {
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log.Println("Error encoding message:", err)
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continue
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}
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msg_len := len(msg)
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if msg_len >= MSG_SIZE_LIMIT {
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log.Println("Message over webextension limit. Discarding")
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continue
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}
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len_buf := make([]byte, 4)
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binary.LittleEndian.PutUint32(len_buf, uint32(msg_len))
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log.Println(len_buf, string(msg))
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fmt.Print(string(len_buf))
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fmt.Print(string(msg))
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}
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}()
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// Accept connections
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for {
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conn, err := l.Accept()
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if err != nil {
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log.Println("Error accepting conn:", err)
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}
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go conn_hndlr(conn, msg_pipe)
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}
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}
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func conn_hndlr(c net.Conn, ch chan<- string) {
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defer c.Close()
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log.Println("Connection opened:", c)
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for {
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msg, err := read_msg(c)
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if err != nil {
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break
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}
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ch <- msg
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}
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log.Println("Closing connection:", c)
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}
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func read_msg(c net.Conn) (string, error) {
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len_buf := make([]byte, 4)
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if _, err := io.ReadFull(c, len_buf); err != nil {
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log.Println("Len read error:", err)
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return "", err
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}
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msg_len := binary.LittleEndian.Uint32(len_buf)
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msg_buf := make([]byte, msg_len)
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if _, err := io.ReadFull(c, msg_buf); err != nil {
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log.Println("Msg read error:", err)
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return "", err
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}
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return string(msg_buf), nil
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}
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