Initial commit

server/ssh/handle.go

@@ -0,0 +1,79 @@
+package ssh
+
+import (
+	"docker4ssh/docker"
+	"fmt"
+	"go.uber.org/zap"
+	"golang.org/x/crypto/ssh"
+)
+
+type RequestType string
+
+const (
+	RequestPtyReq       RequestType = "pty-req"
+	RequestWindowChange RequestType = "window-change"
+)
+
+type PtyReqPayload struct {
+	Term string
+
+	Width, Height           uint32
+	PixelWidth, PixelHeight uint32
+
+	Modes []byte
+}
+
+func handleChannels(chans <-chan ssh.NewChannel, client *docker.Client, user *User) {
+	for channel := range chans {
+		go handleChannel(channel, client, user)
+	}
+}
+
+func handleChannel(channel ssh.NewChannel, client *docker.Client, user *User) {
+	if t := channel.ChannelType(); t != "session" {
+		channel.Reject(ssh.UnknownChannelType, fmt.Sprintf("unknown channel type: %s", t))
+		return
+	}
+
+	conn, requests, err := channel.Accept()
+	if err != nil {
+		zap.S().Warnf("Failed to accept channel for user %s", user.ID)
+		return
+	}
+	defer conn.Close()
+	user.Terminal.ReadWriter = conn
+
+	// handle all other request besides the normal user input.
+	// currently, only 'pty-req' is implemented which determines a terminal size change
+	go handleRequest(requests, user)
+
+	// this handles the actual user terminal connection.
+	// blocks until the session has finished
+	connection(client, user)
+
+	zap.S().Debugf("Session for user %s ended", user.ID)
+}
+
+func handleRequest(requests <-chan *ssh.Request, user *User) {
+	for request := range requests {
+		switch RequestType(request.Type) {
+		case RequestPtyReq:
+			// this could spam the logs when the user resizes his window constantly
+			// log()
+
+			var ptyReq PtyReqPayload
+			ssh.Unmarshal(request.Payload, &ptyReq)
+
+			user.Terminal.Width = ptyReq.Width
+			user.Terminal.Height = ptyReq.Height
+		case RequestWindowChange:
+			// prevent from logging
+		default:
+			zap.S().Debugf("New request from user %s - Type: %s, Want Reply: %t, Payload: '%s'", user.ID, request.Type, request.WantReply, request.Payload)
+		}
+
+		if request.WantReply {
+			request.Reply(true, nil)
+		}
+	}
+}