《计算机网络简易速速上手小册》第1章：计算机网络技术基础（2024 最新版）

from http.server import HTTPServer, BaseHTTPRequestHandler
class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200)
        self.send_header('Content-type', 'text/html')
        self.end_headers()
        self.wfile.write(b'Hello, World! This is a simple HTTP server.')
httpd = HTTPServer(('localhost', 8000), SimpleHTTPRequestHandler)
print("Serving HTTP on localhost port 8000...")
httpd.serve_forever()

from scapy.all import sniff
def packet_callback(packet):
    if packet.haslayer(IP):
        ip_src = packet[IP].src
        ip_dst = packet[IP].dst
        print(f"Packet: {ip_src} -> {ip_dst}")
print("Sniffing packets...")
sniff(prn=packet_callback, count=10)

import socket
def create_tcp_connection():
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind(('localhost', 9999))
    s.listen(1)
    print("Waiting for a connection on localhost port 9999...")
    
    conn, addr = s.accept()
    print(f"Connected by {addr}")
    while True:
        data = conn.recv(1024)
        if not data:
            break
        conn.sendall(data)
    conn.close()
create_tcp_connection()

import socket
def tcp_server():
    host = 'localhost'
    port = 12345
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((host, port))
        s.listen()
        print(f"TCP Server listening on {host}:{port}")
        conn, addr = s.accept()
        with conn:
            print(f"Connected by {addr}")
            while True:
                data = conn.recv(1024)
                if not data:
                    break
                conn.sendall(data)
tcp_server()

import socket
def tcp_client():
    host = 'localhost'
    port = 12345
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((host, port))
        s.sendall(b'Hello, TCP Server')
        data = s.recv(1024)
        print(f"Received {data.decode()} from server")
tcp_client()

import socket
def file_transfer_server():
    host = 'localhost'
    port = 12346
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((host, port))
        s.listen()
        print(f"File Transfer Server listening on {host}:{port}")
        conn, addr = s.accept()
        with conn:
            print(f"Connected by {addr}")
            with open('received_file.txt', 'wb') as f:
                while True:
                    data = conn.recv(1024)
                    if not data:
                        break
                    f.write(data)
            print("File has been received.")
file_transfer_server()

import socket
def file_transfer_client():
    host = 'localhost'
    port = 12346
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((host, port))
        with open('send_file.txt', 'rb') as f:
            s.sendfile(f)
        print("File has been sent.")
file_transfer_client()

import requests
def simple_web_crawler(url):
    response = requests.get(url)
    if response.status_code == 200:
        with open("page.html",
 "w", encoding='utf-8') as f:
            f.write(response.text)
        print(f"Web page saved successfully.")
    else:
        print("Failed to retrieve the web page.")
simple_web_crawler('http://example.com')

import socket
import threading
def client_thread(conn, addr):
    print(f"Connected with {addr}")
    while True:
        try:
            message = conn.recv(1024).decode('utf-8')
            print(f"Received message from {addr}: {message}")
            for client in clients:
                if client != conn:
                    client.send(f"Message from {addr}: {message}".encode('utf-8'))
        except:
            conn.close()
            break
def chat_server():
    host = 'localhost'
    port = 12345
    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.bind((host, port))
    server_socket.listen()
    print(f"Chat Server started on {host}:{port}")
    while True:
        conn, addr = server_socket.accept()
        clients.append(conn)
        threading.Thread(target=client_thread, args=(conn, addr)).start()
clients = []
chat_server()

import socket
def chat_client():
    host = 'localhost'
    port = 12345
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((host, port))
        while True:
            message = input("Enter message: ")
            s.send(message.encode('utf-8'))
chat_client()

import socket
import threading
def client_handler(connection, address):
    try:
        while True:
            message = connection.recv(1024)
            if not message:
                break
            print(f"Message from {address}: {message.decode()}")
            connection.sendall(b"Message received")
    finally:
        connection.close()
def star_topology_server():
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.bind(('localhost', 10000))
    server.listen(5)
    print("Server listening on port 10000...")
    
    try:
        while True:
            conn, addr = server.accept()
            threading.Thread(target=client_handler, args=(conn, addr)).start()
    finally:
        server.close()
star_topology_server()

from scapy.all import IP, ICMP, send
def simulate_traffic(dst):
    packet = IP(dst=dst)/ICMP()
    send(packet)
simulate_traffic("www.example.com")