BOOTP实现 / BOOTP Implement
目录
Note: 理论部分请参考文末相关阅读链接
服务器建立步骤主要有:
（1） 设定服务器IP，传送ip(offer_ip)，服务端口68，客户端口67;
（2） 建立send_socket/UDP，广播模式允许复用，绑定到服务器ip，客户端端口;
（3） 建立主循环，建立recv_socket进行监听广播地址和客户端口;
（4） Recv_socket进行广播接收，筛选收到的广播报文，对有效报文进行解码;
（5） 解码报文获取相应信息，xid，mac_id等;
（6） 加码回传报文，填入收到的xid，mac_id，server ip，offer ip, 文件名等;
（7） 利用send_socket向68端口以广播形式回复报文;
（8） 判断待传文件是否还有未传送的，是则回到循环等待下一个有效广播请求
Note: BOOTP_CodeC 中的加码实现可参考 BOOTP 加码的 Python 实现部分内容
1 import socket 2 import struct 3 import os 4 from BOOTP_CodeC import ServerCodeC 5 SERVERNAME = ‘Bootpserver‘ 6 7 class BOOTPServer(): 8 def __init__(self): 9 self.server_ip = ‘127.0.0.1‘ 10 self.offer_ip = ‘127.0.0.8‘ 11 self.server_port = 68 # Respond client via this port 12 self.client_port = 67 # Receive client data via this port 13 self.send_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 14 self.send_sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, True) 15 self.send_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True) 16 #self.send_sock.bind((self.server_ip, self.client_port)) 17 self.file_bin = [‘secondboot.b3‘, ‘files4.rc‘] 18 19 def requestCheck(self, m): 20 if not ( 21 m[‘op‘] == b‘\x01‘ and # OP 22 m[‘htype‘] == b‘\x01‘ and # HTYPE 23 m[‘hlen‘] == b‘\x06‘ and # HLEN 24 m[‘hops‘] == b‘\x00‘ and # HOPS 25 m[‘secs‘] == [b‘\x00‘, b‘\x00‘] and # SECS 26 m[‘flags‘] == [b‘\x80‘, b‘\x00‘] and # FLAGS (broadcast) 27 m[‘ciaddr‘] == ‘0.0.0.0‘ and # Client IP Address 28 m[‘yiaddr‘] == ‘0.0.0.0‘ and # Your Client IP Address 29 m[‘siaddr‘] == ‘0.0.0.0‘ and # Server IP 30 m[‘giaddr‘] == ‘0.0.0.0‘ # Gateway IP 31 ): 32 return False 33 if not ( 34 m[‘sname‘] == SERVERNAME or 35 m[‘sname‘] == ‘‘): 36 return False 37 return True 38 39 def server_start(self): 40 file_index = 0 41 while True: 42 if file_index >= len(self.file_bin): 43 break 44 self.rec_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 45 self.rec_sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, True) 46 self.rec_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True) 47 self.rec_sock.bind((‘‘, self.client_port)) 48 print(‘=== Waiting for packet‘) 49 msg, addr = self.rec_sock.recvfrom(1024) 50 msgBody = ServerCodeC.collect(msg) 51 print(‘<<< RECV from %s, client ip is %s, xid: %s, mac id: %s‘ % 52 (addr, msgBody[‘ciaddr‘], msgBody[‘xid‘], msgBody[‘chaddr‘])) 53 if self.requestCheck(msgBody): 54 print(‘=== This is a valid message‘) 55 offer = ServerCodeC.offer(transaction_id=msgBody[‘xid‘], 56 client_ip_offer=self.offer_ip, 57 server_ip=self.server_ip, 58 client_mac_id=msgBody[‘chaddr‘], 59 file_path=self.file_bin[file_index]) 60 self.send_sock.sendto(offer, (‘<broadcast>‘, 68)) 61 print(‘>>> SEND ("<broadcast>", 68), offer ip "%s", file name is "%s"‘ % 62 (self.offer_ip, self.file_bin[file_index])) 63 file_index += 1 64 print(‘=== BOOTP server exit‘) 65 66 server = BOOTPServer() 67 server.server_start()
客户端建立步骤主要有:
（1） 客户端ip未知，服务端口68，客户端口67;
（2） 建立主循环，建立socket/UDP，广播模式允许复用，监听服务端端口;
（3） 广播模式朝客户端口67发送请求报文，请求报文中填入客户端信息，如xid，mac_id等，并等待接收回复报文;
（4） 进行接收等待，若未超时且受到有效报文，则对有效报文进行解码;
（5） 解码报文获取相应信息，确认xid，mac_id与发送时的是否匹配;
（6） 提取报文信息，为后续（TFTP下载启动文件）做准备;
1 import socket 2 import binascii 3 import struct 4 from BOOTP_CodeC import ClientCodeC 5 6 class BOOTPClient(): 7 def __init__(self): 8 self.client_ip = ‘0.0.0.0‘ 9 self.broadcast_ip = ‘255.255.255.255‘ # or ‘<broadcast>‘ 10 self.server_ip = ‘127.0.0.1‘ 11 self.target_port = 67 12 self.source_port = 68 13 ClientCodeC.get_xid_macid() 14 15 def recv_check(self, m): 16 if not ( 17 m[‘op‘] == b‘\x02‘ and # OP 18 m[‘htype‘] == b‘\x01‘ and # HTYPE 19 m[‘hlen‘] == b‘\x06‘ and # HLEN 20 m[‘hops‘] == b‘\x00‘ and # HOPS 21 m[‘secs‘] == [b‘\x00‘, b‘\x00‘] and # SECS 22 m[‘flags‘] == [b‘\x80‘, b‘\x00‘] and # FLAGS (broadcast) 23 m[‘xid‘] == ClientCodeC.transaction_id and 24 m[‘chaddr‘] == ClientCodeC.client_mac_id and 25 len(m[‘file‘]) 26 ): 27 return False 28 return True 29 30 def client_request(self): 31 32 while True: 33 self.client_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 34 self.client_sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, True) 35 self.client_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True) 36 self.client_sock.settimeout(5) 37 #self.client_sock.bind((self.server_ip, 68)) 38 self.client_sock.bind((‘‘, 68)) 39 40 self.client_sock.sendto(ClientCodeC.request(), (‘<broadcast>‘, self.target_port)) 41 print(‘>>> SEND ("<broadcast>", %d) request command‘ % self.target_port) 42 try: 43 data, addr = self.client_sock.recvfrom(1024) 44 except socket.timeout: 45 print(‘=== BOOTP client exit‘) 46 break 47 msgBody = ClientCodeC.collect(data) 48 print(‘<<< RECV‘, addr) 49 if self.recv_check(msgBody): 50 print(‘=== This is a valid message‘) 51 client_ip = msgBody[‘yiaddr‘] 52 server_name = msgBody[‘sname‘] 53 file_name = msgBody[‘file‘] 54 server_ip = msgBody[‘siaddr‘] 55 print(‘=== Server ip: %s, server name: %s, file name: %s, get ip address: %s‘ % 56 (server_name, server_ip, file_name, client_ip)) 57 client = BOOTPClient() 58 client.client_request()
相关阅读
1. BOOTP 基本理论
