/
websocket.go
248 lines (210 loc) · 4.83 KB
/
websocket.go
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package server
import (
"fmt"
"io"
"net"
"net/http"
"strconv"
"strings"
"sync"
"github.com/gin-gonic/gin"
"github.com/gorilla/websocket"
"github.com/json-iterator/go"
log "github.com/lostsnow/cloudrain/logger"
"github.com/lostsnow/cloudrain/telnet"
"github.com/spf13/viper"
)
var json = jsoniter.ConfigCompatibleWithStandardLibrary
var (
lock sync.RWMutex
sessions = make(map[string]*telnet.Session)
)
type sessionTrace interface {
SessionCreated()
SessionClosed()
}
var trace sessionTrace
type wsWrapper struct {
*websocket.Conn
}
func (wsw *wsWrapper) Write(p []byte) (n int, err error) {
writer, err := wsw.Conn.NextWriter(websocket.TextMessage)
if err != nil {
return 0, err
}
return writer.Write(p)
}
func (wsw *wsWrapper) Read(p []byte) (n int, err error) {
for {
msgType, reader, err := wsw.Conn.NextReader()
if err != nil {
return 0, err
}
if msgType != websocket.TextMessage {
continue
}
return reader.Read(p)
}
}
func WebsocketHandler(c *gin.Context) {
if c.Request.URL.Path != "/"+viper.GetString("websocket.path") {
http.Error(c.Writer, "Not found", 404)
return
}
if c.Request.Method != "GET" {
http.Error(c.Writer, "Method not allowed", 405)
return
}
var sidCookie string
cookie, err := c.Request.Cookie("sessionid")
if err == nil {
sidCookie = cookie.Value
}
var tokenCookie string
cookie, err = c.Request.Cookie("token")
if err == nil {
tokenCookie = cookie.Value
}
var ip string
ip = c.Request.Header.Get("X-REAL-IP")
if ip == "" {
ip, _, err = net.SplitHostPort(c.Request.RemoteAddr)
if err != nil {
log.Error(err)
return
}
}
upgrader := websocket.Upgrader{
CheckOrigin: func(r *http.Request) bool { return true },
}
up, err := upgrader.Upgrade(c.Writer, c.Request, nil)
if err != nil {
http.Error(c.Writer, "Error creating websocket", 500)
log.Error("Error creating websocket: ", err)
return
}
log.Info("Opening a proxy for ", c.Request.RemoteAddr)
rw := io.ReadWriteCloser(&wsWrapper{up})
me := telnet.NewMultiWriterEntry(rw)
onClose := func(s *telnet.Session) {
lock.Lock()
defer lock.Unlock()
delete(sessions, s.Id())
log.Infof("session ended %s.", plural(len(sessions)))
if trace != nil {
trace.SessionClosed()
}
}
up.SetCloseHandler(func(code int, text string) error {
if err = up.Close(); err != nil {
log.Error(err)
}
return nil
})
var t telnet.Telnet
err = viper.UnmarshalKey("telnet", &t)
if err != nil {
log.Errorf("invalid telnet config: %v", t)
return
}
var sess *telnet.Session
var sid string
if t.MultiConnection {
sid = c.Request.URL.Query().Get("sid")
if sid == "" && sidCookie != "" {
sid = sidCookie
}
if sid != "" && tokenCookie != "" {
log.Infof("try to attach session %s, %s.", sid, plural(len(sessions)))
if attachToExistingSession(sid, tokenCookie, me) {
go handleCommand(up, sessions[sid])
return
} else {
sid = ""
}
}
}
sess, err = t.NewSession(sid, rw, onClose)
if err == nil {
sess.RemoteIp = ip
lock.Lock()
defer lock.Unlock()
sessions[sess.Id()] = sess
log.Infof("session started %s, %s.", sess.Id(), plural(len(sessions)))
if trace != nil {
trace.SessionCreated()
}
go handleCommand(up, sess)
} else {
log.Errorf("error on session start: %s", err.Error())
if err = up.Close(); err != nil {
log.Error(err)
}
}
}
func attachToExistingSession(sid, token string, me *telnet.MultiWriterEntry) bool {
lock.RLock()
defer lock.RUnlock()
sess, ok := sessions[sid]
if !ok {
return false
}
if sess.Token() != token {
log.Errorf("invalid session %s token %s", sid, token)
return false
}
err := sess.Attach(me)
if err == nil {
log.Infof("session attached %s, %s", sid, plural(len(sessions)))
} else {
log.Errorf("error on session attach %s: %s", sid, err.Error())
}
return true
}
func plural(value int) string {
if value == 0 {
return "(no active sessions)"
} else if value == 1 {
return "(1 active session)"
} else {
return "(" + strconv.Itoa(value) + " active sessions)"
}
}
type command struct {
Type string
Content string
}
// Send messages from the websocket to the telnet.
func handleCommand(ws *websocket.Conn, sess *telnet.Session) {
for {
_, bs, err := ws.ReadMessage()
if err != nil {
log.Errorf("Error reading from ws(%s): %v", ws.RemoteAddr(), err)
break
}
cmd := command{}
if err = json.Unmarshal(bs, &cmd); err != nil {
log.Error(err)
continue
}
t := cmd.Type
switch t {
case "cmd":
sess.SendCommand(cmd.Content + "\n")
case "naws":
var w, h int
_, err := fmt.Sscanf(cmd.Content, "%d,%d", &w, &h)
if err == nil {
sess.SendNaws(byte(w), byte(h))
}
case "atcp":
sess.SendAtcp(cmd.Content)
case "mxp":
sess.SendMxp(cmd.Content)
case "gmcp":
sess.SendGmcp(strings.TrimSpace(cmd.Content))
default:
log.Error(telnet.ErrInvalidCommand)
}
}
}