计网课设-发送TCP数据包

一、效果展示

二、代码实现

import nmap
import socket
import tkinter as tk
from tkinter import messagebox,Listbox
from threading import Thread

#获取自身IP，从而确定当前局域网范围
def get_ip_address():
    #创建了一个socket对象，socket.AF_INET表示使用IPv4地址族，socket.SOCK_DGRAM表示使用UDP
    #使用UDP是因为不需要真正发送数据，通过连接一个地址来促使系统分配一个端口
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    try:
        # 不需要真正发送数据，所以使用一个不存在的地址
        #这段代码目的让操作系统分配一个本地端口，并返回当前机器IP
        s.connect(('255.255.255.255', 1))
        ip = s.getsockname()[0]
        print(s.getsockname())
        #print(type(s.getsockname()))
    except Exception as e:
        print(e)
    finally:
        s.close()
        # 找到第三个'.'的位置
        dot_index = ip.rfind('.')
        # print(dot_index)
        # 替换第三个'.'及其后的内容
        new_ip = ip[:dot_index] + '.0/24'
    return new_ip

def scan_local_network(listbox):
    nm = nmap.PortScanner()
    try:
        # 执行主机发现扫描
        network = get_ip_address()
        nm.scan(hosts=network, arguments='-sn')

        #清空列表框
        listbox.delete(0,tk.END)

        # 打印扫描结果
        for host in nm.all_hosts():
            status = nm[host].state()
            if status == 'up':
                listbox.insert(tk.END,host)
    except nmap.PortScannerError as e:
        messagebox.showerror("扫描失败",f"An error occurred:{e}")


# 发送TCP消息的函数
def send_message():
    ip = ip_entry.get()
    port = int(port_entry.get())
    message = message_entry.get()
    try:
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
            sock.connect((ip, port))
            sock.sendall(message.encode())
            messagebox.showinfo("发送成功", "消息已发送到" + ip)
    except Exception as e:
        messagebox.showerror("发送失败", str(e))

# 更新IP输入框的函数
def update_ip(ip):
    ip_entry.delete(0, tk.END)
    ip_entry.insert(0, ip)


# 定义启动TCP服务器的函数
def start_server(port):
    global server_socket
    try:
        server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        server_socket.bind(('0.0.0.0', port))  # 监听所有接口上的端口
        server_socket.listen(1)
        messagebox.showinfo("服务器启动", f"服务器正在监听端口 {port}")
        while True:
            client_socket, addr = server_socket.accept()
            with client_socket:
                while True:
                    data = client_socket.recv(1024)
                    if not data:
                        break
                    message_text.insert(tk.END, f"从{addr}接收到消息: {data.decode()}\n")
                client_socket.close()
    except Exception as e:
        messagebox.showerror("接收消息失败", str(e))
    finally:
        if 'server_socket' in globals() and server_socket:
            server_socket.close()

# 在GUI中启动服务器的按钮
def start_server_button_clicked():
    port = int(port_entry.get())  # 获取用户输入的端口
    server_thread = Thread(target=start_server, args=(port,))
    server_thread.start()  # 启动线程


# 初始化GUI界面
root = tk.Tk()
root.title("TCP消息发送器")

# 使用grid布局管理器
root.columnconfigure(0, weight=1)
root.columnconfigure(1, weight=2)

# IP输入框
ip_label = tk.Label(root, text="IP:")
ip_label.grid(row=0, column=0, padx=10, pady=5, sticky='e')
ip_entry = tk.Entry(root, width=20)
ip_entry.grid(row=0, column=1, padx=10, pady=5)

# 端口输入框
port_label = tk.Label(root, text="PORT:")
port_label.grid(row=1, column=0, padx=10, pady=5, sticky='e')
port_entry = tk.Entry(root, width=20)
port_entry.grid(row=1, column=1, padx=10, pady=5)

# 消息输入框
message_label = tk.Label(root, text="Message:")
message_label.grid(row=2, column=0, padx=10, pady=5, sticky='e')
message_entry = tk.Entry(root, width=50)
message_entry.grid(row=2, column=1, padx=10, pady=5)

# 扫描按钮
scan_button = tk.Button(root, text="扫描局域网", command=lambda: scan_local_network(results_listbox))
scan_button.grid(row=3, column=0, padx=10, pady=5, sticky='w')

# 发送按钮
send_button = tk.Button(root, text="发送", command=send_message)
send_button.grid(row=3, column=1, padx=10, pady=5, sticky='w')

# 启动服务器按钮
start_server_button = tk.Button(root, text="启动服务器", command=start_server_button_clicked)
start_server_button.grid(row=4, column=1, padx=10, pady=5, sticky='w')

# 显示扫描结果的列表框
results_listbox = tk.Listbox(root, width=35, height=10)
results_listbox.grid(row=5, column=0, columnspan=2, padx=10, pady=5, sticky='nsew')

# 消息显示区域
message_text = tk.Text(root, width=50, height=10, wrap='word')
message_text.grid(row=6, column=0, columnspan=2, padx=10, pady=5, sticky='nsew')

# 监听端口标签和输入框（放置在Frame中以避免布局冲突）
frame = tk.Frame(root)
frame.grid(row=7, column=0, columnspan=2, padx=10, pady=5, sticky='ew')

listen_port_label = tk.Label(frame, text="Listening Port:")
listen_port_label.pack(side=tk.LEFT, padx=10, pady=5)
listen_port_entry = tk.Entry(frame, width=20)
listen_port_entry.pack(side=tk.LEFT, padx=10, pady=5)

# 为扫描结果列表框添加选择事件
#event参数是tkinter事件对象，包含了事件相关信息
def on_select(event):
    #通过事件对象的widget属性获取触发事件的组件，即被点击的列表框
    w = event.widget
    #调用列表框w的curselection()方法，获取当前被选中的项目索引列表，如果没有项目被选中，则返回空列表
    selection = w.curselection()
    if selection:
        #事实上curselection返回的只有一个值
        index = selection[0]
        #获取IP
        ip = w.get(index)
        #更新IP
        update_ip(ip)

#将on_select函数绑定到results_listbox列表框的<<ListboxSelect>>事件上，意味着每当列表框中的项目被选中时，
#就会触发on_select函数
results_listbox.bind('<<ListboxSelect>>', on_select)

# 启动GUI主循环
root.mainloop()