From 85bfc370e0beb04825866deb7435724339a602bc Mon Sep 17 00:00:00 2001
From: Jeremy Norris <jeremy.norris@localbackhaul.com>
Date: Fri, 2 Sep 2022 14:07:42 -0500
Subject: [PATCH] #201 add missing JumpHosts.java, pulled from
 http://www.jcraft.com/jsch/examples/JumpHosts.java.

---
 examples/JumpHosts.java | 168 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 examples/JumpHosts.java

diff --git a/examples/JumpHosts.java b/examples/JumpHosts.java
new file mode 100644
index 00000000..ad7b0b62
--- /dev/null
+++ b/examples/JumpHosts.java
@@ -0,0 +1,168 @@
+/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
+/**
+ * This program will demonstrate SSH through jump hosts.
+ * Suppose that you don't have direct accesses to host2 and host3.
+ *   $ CLASSPATH=.:../build javac JumpHosts.java
+ *   $ CLASSPATH=.:../build java JumpHosts usr1@host1 usr2@host2 usr3@host3
+ * You will be asked passwords for those destinations,
+ * and if everything works fine, you will get file lists of your home-directory
+ * at host3.
+ *
+ */
+import com.jcraft.jsch.*;
+import java.awt.*;
+import javax.swing.*;
+
+public class JumpHosts {
+  public static void main(String[] arg){
+
+    try{
+      JSch jsch = new JSch();
+
+      if(arg.length <= 1){
+        System.out.println("This program expects more arguments.");
+        System.exit(-1);
+      }
+
+      Session session = null;
+      Session[] sessions = new Session[arg.length];
+
+      String host = arg[0];
+      String user = host.substring(0, host.indexOf('@'));
+      host = host.substring(host.indexOf('@')+1);
+
+      sessions[0] = session = jsch.getSession(user, host, 22);
+      session.setUserInfo(new MyUserInfo());
+      session.connect();
+      System.out.println("The session has been established to "+user+"@"+host);
+
+      for(int i = 1; i < arg.length; i++){
+        host = arg[i];
+        user = host.substring(0, host.indexOf('@'));
+        host = host.substring(host.indexOf('@')+1);
+
+        int assinged_port = session.setPortForwardingL(0, host, 22);
+        System.out.println("portforwarding: "+
+                           "localhost:"+assinged_port+" -> "+host+":"+22);
+        sessions[i] = session =
+          jsch.getSession(user, "127.0.0.1", assinged_port);
+
+        session.setUserInfo(new MyUserInfo());
+        session.setHostKeyAlias(host);
+        session.connect();
+        System.out.println("The session has been established to "+
+                           user+"@"+host);
+      }
+
+      ChannelSftp sftp = (ChannelSftp)session.openChannel("sftp");
+
+      sftp.connect();
+      sftp.ls(".",
+              new ChannelSftp.LsEntrySelector() {
+                public int select(ChannelSftp.LsEntry le) {
+                  System.out.println(le);
+                  return ChannelSftp.LsEntrySelector.CONTINUE;
+                }
+              });
+      sftp.disconnect();
+
+      for(int i = sessions.length-1; i >= 0; i--){
+        sessions[i].disconnect();
+      }
+    }
+    catch(Exception e){
+      System.out.println(e);
+    }
+  }
+
+  public static class MyUserInfo implements UserInfo, UIKeyboardInteractive{
+    public String getPassword(){ return passwd; }
+    public boolean promptYesNo(String str){
+      Object[] options={ "yes", "no" };
+      int foo=JOptionPane.showOptionDialog(null, 
+             str,
+             "Warning", 
+             JOptionPane.DEFAULT_OPTION, 
+             JOptionPane.WARNING_MESSAGE,
+             null, options, options[0]);
+       return foo==0;
+    }
+  
+    String passwd;
+    JTextField passwordField=(JTextField)new JPasswordField(20);
+
+    public String getPassphrase(){ return null; }
+    public boolean promptPassphrase(String message){ return true; }
+    public boolean promptPassword(String message){
+      Object[] ob={passwordField}; 
+      int result=
+	  JOptionPane.showConfirmDialog(null, ob, message,
+					JOptionPane.OK_CANCEL_OPTION);
+      if(result==JOptionPane.OK_OPTION){
+	passwd=passwordField.getText();
+	return true;
+      }
+      else{ return false; }
+    }
+    public void showMessage(String message){
+      JOptionPane.showMessageDialog(null, message);
+    }
+    final GridBagConstraints gbc = 
+      new GridBagConstraints(0,0,1,1,1,1,
+                             GridBagConstraints.NORTHWEST,
+                             GridBagConstraints.NONE,
+                             new Insets(0,0,0,0),0,0);
+    private Container panel;
+    public String[] promptKeyboardInteractive(String destination,
+                                              String name,
+                                              String instruction,
+                                              String[] prompt,
+                                              boolean[] echo){
+      panel = new JPanel();
+      panel.setLayout(new GridBagLayout());
+
+      gbc.weightx = 1.0;
+      gbc.gridwidth = GridBagConstraints.REMAINDER;
+      gbc.gridx = 0;
+      panel.add(new JLabel(instruction), gbc);
+      gbc.gridy++;
+
+      gbc.gridwidth = GridBagConstraints.RELATIVE;
+
+      JTextField[] texts=new JTextField[prompt.length];
+      for(int i=0; i<prompt.length; i++){
+        gbc.fill = GridBagConstraints.NONE;
+        gbc.gridx = 0;
+        gbc.weightx = 1;
+        panel.add(new JLabel(prompt[i]),gbc);
+
+        gbc.gridx = 1;
+        gbc.fill = GridBagConstraints.HORIZONTAL;
+        gbc.weighty = 1;
+        if(echo[i]){
+          texts[i]=new JTextField(20);
+        }
+        else{
+          texts[i]=new JPasswordField(20);
+        }
+        panel.add(texts[i], gbc);
+        gbc.gridy++;
+      }
+
+      if(JOptionPane.showConfirmDialog(null, panel, 
+                                       destination+": "+name,
+                                       JOptionPane.OK_CANCEL_OPTION,
+                                       JOptionPane.QUESTION_MESSAGE)
+         ==JOptionPane.OK_OPTION){
+        String[] response=new String[prompt.length];
+        for(int i=0; i<prompt.length; i++){
+          response[i]=texts[i].getText();
+        }
+	return response;
+      }
+      else{
+        return null;  // cancel
+      }
+    }
+  }
+}