chat.py

# File: chat.py
# Function: Cross-domain chat tool GUI based on L2-VPN
# Author: Cyans from Chang'an University


import tkinter as tk
from tkinter import scrolledtext, messagebox, font
import socket
import threading
import os
import sys
import subprocess
import time
import datetime

# ==================== User Configuration ====================
ROLE = 'A'  # 'A' or 'B'

SERVER_IP = "" # <--- Please fill in your Server IP here
SERVER_PORT = "9999"
INTERFACE_NAME = "qwq"
CHAT_PORT = 12345

if ROLE == 'A':
    MY_NAME = "Alice"
    MY_VIRTUAL_IP = "10.0.0.1"
    TARGET_IP = "10.0.0.2"
else:
    MY_NAME = "Bob"
    MY_VIRTUAL_IP = "10.0.0.2"
    TARGET_IP = "10.0.0.1"
# ============================================================

class QwQChatApp:
    def __init__(self, root):
        self.root = root
        self.root.title(f"QwQ L2-Link - {MY_NAME}")
        self.root.geometry("700x550")

        if os.geteuid() == 0:
            messagebox.showwarning("Launch Error", "Do NOT run with sudo!\nRun directly: python3 chat.py\n(We will ask for sudo password later)")
            sys.exit(1)

        self.bg_color = "#F5F5F5"
        self.chat_bg_color = "#EBEDF0"
        self.my_msg_color = "#0099FF"
        self.peer_msg_color = "#333333"
        self.root.configure(bg=self.bg_color)

        if not self.pre_auth_sudo():
            sys.exit(1)

        self.vpn_process = None
        self.init_system()

        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        try:
            self.sock.bind((MY_VIRTUAL_IP, CHAT_PORT))
        except Exception as e:
            messagebox.showerror("Error", f"Port bind failed: {e}")
            self.cleanup()
            sys.exit(1)

        self.setup_ui()

        self.stop_event = threading.Event()
        self.recv_thread = threading.Thread(target=self.receive_loop, daemon=True)
        self.recv_thread.start()

        self.root.protocol("WM_DELETE_WINDOW", self.on_closing)

    def pre_auth_sudo(self):
        print("\n" + "="*50)
        print("[Sudo Request] Please enter sudo password to start VPN core:")
        print("Note: Password will not be visible. Press Enter after typing.")
        print("="*50 + "\n")
        ret = os.system("sudo -v")
        if ret != 0:
            print("\n[X] Password incorrect or cancelled. Exiting.")
            return False
        print("\n[V] Authorization successful! Starting GUI...")
        return True

    def run_sudo(self, cmd):
        return os.system(f"sudo {cmd}")

    def init_system(self):
        self.run_sudo("killall -9 client 2>/dev/null")
        self.run_sudo(f"ip link delete {INTERFACE_NAME} 2>/dev/null")
        time.sleep(0.5)

        if not os.path.exists("./client"):
            print("[*] Compiling C client...")
            ret = os.system("gcc client.c tap.c -o client -lpthread")
            if ret != 0:
                messagebox.showerror("Error", "Compilation failed")
                sys.exit(1)

        print(f"[*] Starting background VPN connection to {SERVER_IP}...")
        self.vpn_process = subprocess.Popen(
            ["sudo", "./client", SERVER_IP, SERVER_PORT],
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL
        )
        
        time.sleep(1)
        if self.vpn_process.poll() is not None:
            messagebox.showerror("Connection Failed", "VPN Core failed to start!\nPlease check Server IP.")
            sys.exit(1)
            
        self.run_sudo(f"ip addr add {MY_VIRTUAL_IP}/24 dev {INTERFACE_NAME}")
        self.run_sudo(f"ip link set {INTERFACE_NAME} up")
        print(f"[*] Network Ready! Local IP: {MY_VIRTUAL_IP}")

    def setup_ui(self):
        try:
            self.custom_font = font.Font(family="Microsoft YaHei", size=11)
        except:
            self.custom_font = font.Font(family="Arial", size=11)
        
        top_frame = tk.Frame(self.root, bg=self.my_msg_color, height=40)
        top_frame.pack(fill=tk.X, side=tk.TOP)
        tk.Label(top_frame, text=f"Encrypted Chat with {TARGET_IP}", bg=self.my_msg_color, fg="white", font=("Arial", 10, "bold")).pack(pady=8)

        bottom_frame = tk.Frame(self.root, bg="white", height=50)
        bottom_frame.pack(fill=tk.X, side=tk.BOTTOM)

        self.msg_entry = tk.Entry(bottom_frame, font=("Arial", 12), bd=0, bg="#F0F0F0", relief=tk.FLAT)
        self.msg_entry.pack(side=tk.LEFT, fill=tk.BOTH, expand=True, padx=15, pady=15)
        self.msg_entry.bind("<Return>", lambda event: self.send_msg())
        self.msg_entry.focus_set()

        send_btn = tk.Button(bottom_frame, text="Send", command=self.send_msg, bg=self.my_msg_color, fg="white", font=("Arial", 10, "bold"), relief=tk.FLAT, padx=20)
        send_btn.pack(side=tk.RIGHT, padx=10, pady=10)

        self.chat_display = scrolledtext.ScrolledText(
            self.root, state='disabled', font=self.custom_font, bg=self.chat_bg_color, bd=0, padx=10, pady=10
        )
        self.chat_display.pack(padx=0, pady=0, fill=tk.BOTH, expand=True)
        
        self.chat_display.tag_config('me', foreground=self.my_msg_color, justify='right', rmargin=10)
        self.chat_display.tag_config('peer', foreground=self.peer_msg_color, justify='left', lmargin1=10, lmargin2=10)
        self.chat_display.tag_config('system', foreground='#999999', justify='center', font=("Arial", 9))

 

    def append_msg(self, name, msg, tag):
        self.chat_display.config(state='normal')
        now = datetime.datetime.now().strftime("%H:%M")
        
        if tag == 'me':
            self.chat_display.insert(tk.END, f"{now} {name}\n", tag)
            self.chat_display.insert(tk.END, f"{msg}\n\n", tag)
        else:
            self.chat_display.insert(tk.END, f"{name} {now}\n", tag)
            self.chat_display.insert(tk.END, f"{msg}\n\n", tag)
            
        self.chat_display.see(tk.END)
        self.chat_display.config(state='disabled')

    def append_system_msg(self, msg):
        self.chat_display.config(state='normal')
        self.chat_display.insert(tk.END, f"\n=== {msg} ===\n\n", 'system')
        self.chat_display.config(state='disabled')

    def send_msg(self):
        msg = self.msg_entry.get().strip()
        if not msg:
            return
        try:
            self.sock.sendto(msg.encode('utf-8'), (TARGET_IP, CHAT_PORT))
            self.append_msg("Me", msg, 'me')
            self.msg_entry.delete(0, tk.END)
        except Exception as e:
            self.append_system_msg(f"Send Failed: {e}")

    def receive_loop(self):
        while not self.stop_event.is_set():
            try:
                self.sock.settimeout(1.0)
                try:
                    data, addr = self.sock.recvfrom(4096)
                    msg_text = data.decode('utf-8')
                    self.chat_display.after(0, self.append_msg, "Peer", msg_text, 'peer')
                except socket.timeout:
                    continue
                except UnicodeDecodeError:
                    self.chat_display.after(0, self.append_msg, "Peer", "[Non-text data]", 'peer')
            except Exception as e:
                print(f"Receive error: {e}")
                break
    
    def cleanup(self):
        if self.vpn_process:
            self.run_sudo("kill -TERM " + str(self.vpn_process.pid))
        self.run_sudo("killall -9 client 2>/dev/null")
        self.run_sudo(f"ip link delete {INTERFACE_NAME} 2>/dev/null")

    def on_closing(self):
        self.stop_event.set()
        self.cleanup()
        self.root.destroy()
        sys.exit(0)

if __name__ == "__main__":
    root = tk.Tk()
    app = QwQChatApp(root)
    root.mainloop()