187 lines
3.9 KiB
Go
187 lines
3.9 KiB
Go
package main
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import (
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"context"
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"encoding/binary"
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"encoding/json"
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"fmt"
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"html/template"
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"io"
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"log"
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"net"
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"net/http"
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"os"
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"time"
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"golang.org/x/net/websocket"
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)
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var (
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addressBind string
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addressConnect string
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)
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func clientToRelay(
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ctx context.Context, ws *websocket.Conn, conn net.Conn) bool {
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var j string
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if err := websocket.Message.Receive(ws, &j); err != nil {
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log.Println("Command receive failed: " + err.Error())
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return false
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}
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log.Printf("?> %s\n", j)
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var m RelayCommandMessage
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if err := json.Unmarshal([]byte(j), &m); err != nil {
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log.Println("Command unmarshalling failed: " + err.Error())
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return false
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}
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b, ok := m.AppendTo(make([]byte, 4))
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if !ok {
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log.Println("Command serialization failed")
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return false
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}
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binary.BigEndian.PutUint32(b[:4], uint32(len(b)-4))
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if _, err := conn.Write(b); err != nil {
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log.Println("Command send failed: " + err.Error())
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return false
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}
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log.Printf("-> %v\n", b)
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return true
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}
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func relayToClient(
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ctx context.Context, ws *websocket.Conn, conn net.Conn) bool {
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var length uint32
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if err := binary.Read(conn, binary.BigEndian, &length); err != nil {
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log.Println("Event receive failed: " + err.Error())
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return false
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}
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b := make([]byte, length)
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if _, err := io.ReadFull(conn, b); err != nil {
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log.Println("Event receive failed: " + err.Error())
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return false
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}
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log.Printf("<? %v\n", b)
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var m RelayEventMessage
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if after, ok := m.ConsumeFrom(b); !ok {
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log.Println("Event deserialization failed")
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return false
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} else if len(after) != 0 {
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log.Println("Event deserialization failed: trailing data")
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return false
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}
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j, err := json.Marshal(&m)
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if err != nil {
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log.Println("Event marshalling failed: " + err.Error())
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return false
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}
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if err := websocket.Message.Send(ws, string(j)); err != nil {
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log.Println("Event send failed: " + err.Error())
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return false
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}
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log.Printf("<- %s\n", j)
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return true
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}
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func errorToClient(ws *websocket.Conn, err error) bool {
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j, err := json.Marshal(&RelayEventMessage{
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EventSeq: 0,
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Data: RelayEventData{
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Interface: RelayEventDataError{
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Event: RelayEventError,
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CommandSeq: 0,
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Error: err.Error(),
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},
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},
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})
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if err != nil {
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log.Println("Event marshalling failed: " + err.Error())
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return false
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}
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if err := websocket.Message.Send(ws, string(j)); err != nil {
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log.Println("Event send failed: " + err.Error())
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return false
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}
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return true
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}
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func handleWebSocket(ws *websocket.Conn) {
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conn, err := net.Dial("tcp", addressConnect)
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if err != nil {
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errorToClient(ws, err)
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return
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}
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// We don't need to intervene, so it's just two separate pipes so far.
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ctx, cancel := context.WithCancel(ws.Request().Context())
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go func() {
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for clientToRelay(ctx, ws, conn) {
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}
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cancel()
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}()
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go func() {
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for relayToClient(ctx, ws, conn) {
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}
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cancel()
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}()
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<-ctx.Done()
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}
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var staticHandler = http.FileServer(http.Dir("."))
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var page = template.Must(template.New("/").Parse(`<!DOCTYPE html>
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<html>
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<head>
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<title>xP</title>
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<meta charset="utf-8" />
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<link rel="stylesheet" href="xP.css" />
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</head>
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<body>
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<script src="mithril.js">
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</script>
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<script>
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let proxy = '{{ . }}'
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</script>
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<script src="xP.js">
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</script>
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</body>
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</html>`))
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func handleDefault(w http.ResponseWriter, r *http.Request) {
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if r.URL.Path != "/" {
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staticHandler.ServeHTTP(w, r)
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return
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}
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wsURI := fmt.Sprintf("ws://%s/ws", r.Host)
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if err := page.Execute(w, wsURI); err != nil {
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log.Println("Template execution failed: " + err.Error())
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}
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}
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func main() {
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if len(os.Args) != 3 {
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log.Fatalf("usage: %s BIND CONNECT\n", os.Args[0])
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}
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addressBind, addressConnect = os.Args[1], os.Args[2]
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http.Handle("/ws", websocket.Handler(handleWebSocket))
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http.Handle("/", http.HandlerFunc(handleDefault))
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s := &http.Server{
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Addr: addressBind,
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ReadTimeout: 60 * time.Second,
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WriteTimeout: 60 * time.Second,
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MaxHeaderBytes: 32 << 10,
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}
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log.Fatal(s.ListenAndServe())
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}
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