157 lines
5.1 KiB
Python
157 lines
5.1 KiB
Python
#!/usr/bin/env python3
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"""
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轻量 DHCP Server — 用于 CH395F Phase 6 测试
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用法：以管理员身份运行
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python dhcp_server.py --iface 192.168.1.2
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"""
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import socket
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import struct
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import argparse
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import time
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DHCP_SERVER_PORT = 67
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DHCP_CLIENT_PORT = 68
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# DHCP 消息类型
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DHCP_DISCOVER = 1
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DHCP_OFFER = 2
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DHCP_REQUEST = 3
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DHCP_ACK = 5
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# DHCP 选项
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OPT_MESSAGE_TYPE = 53
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OPT_SERVER_ID = 54
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OPT_REQUESTED_IP = 50
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OPT_SUBNET_MASK = 1
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OPT_ROUTER = 3
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OPT_DNS = 6
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OPT_LEASE_TIME = 51
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OPT_END = 255
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SERVER_IP = "192.168.1.2"
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OFFER_IP = "192.168.1.100"
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SUBNET_MASK = "255.255.255.0"
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ROUTER = "192.168.1.1"
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LEASE_TIME = 3600 # 1 小时
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def ip_to_bytes(ip):
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return bytes(map(int, ip.split('.')))
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def build_dhcp_offer(discover_pkt, server_ip, offer_ip):
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"""构建 DHCP OFFER 包"""
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transaction_id = discover_pkt[232:236] # Bootp header 前 4 字节
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client_mac = discover_pkt[28:34]
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# BOOTP 头
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op = b'\x02' # Boot reply
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htype = b'\x01' # Ethernet
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hlen = b'\x06' # MAC len
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hops = b'\x00'
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xid = transaction_id
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secs = b'\x00\x00'
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flags = b'\x00\x00'
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ciaddr = b'\x00\x00\x00\x00'
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yiaddr = ip_to_bytes(offer_ip) # Your IP
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siaddr = ip_to_bytes(server_ip) # Server IP
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giaddr = b'\x00\x00\x00\x00'
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chaddr = client_mac + b'\x00' * 10 # Client MAC (padded to 16)
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sname = b'\x00' * 64
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file = b'\x00' * 128
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magic = b'\x63\x82\x53\x63' # DHCP magic cookie
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# DHCP 选项
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options = b''
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options += struct.pack('BBB', OPT_MESSAGE_TYPE, 1, DHCP_OFFER)
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options += struct.pack('BB', OPT_SERVER_ID, 4) + ip_to_bytes(server_ip)
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options += struct.pack('BB', OPT_REQUESTED_IP, 4) + ip_to_bytes(offer_ip)
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options += struct.pack('BB', OPT_SUBNET_MASK, 4) + ip_to_bytes(SUBNET_MASK)
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options += struct.pack('BB', OPT_ROUTER, 4) + ip_to_bytes(ROUTER)
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options += struct.pack('BB', OPT_DNS, 4) + ip_to_bytes(ROUTER)
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options += bytes([OPT_LEASE_TIME, 4]) + struct.pack('!I', LEASE_TIME)
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options += bytes([OPT_END])
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pkt = op + htype + hlen + hops + xid + secs + flags + ciaddr + yiaddr + siaddr + giaddr + chaddr + sname + file + magic + options
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return pkt
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def build_dhcp_ack(request_pkt, server_ip, offer_ip):
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"""构建 DHCP ACK 包"""
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transaction_id = request_pkt[232:236]
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client_mac = request_pkt[28:34]
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op = b'\x02'
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htype = b'\x01'
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hlen = b'\x06'
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hops = b'\x00'
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xid = transaction_id
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secs = b'\x00\x00'
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flags = b'\x00\x00'
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ciaddr = b'\x00\x00\x00\x00'
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yiaddr = ip_to_bytes(offer_ip)
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siaddr = ip_to_bytes(server_ip)
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giaddr = b'\x00\x00\x00\x00'
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chaddr = client_mac + b'\x00' * 10
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sname = b'\x00' * 64
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file = b'\x00' * 128
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magic = b'\x63\x82\x53\x63'
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options = b''
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options += struct.pack('BBB', OPT_MESSAGE_TYPE, 1, DHCP_ACK)
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options += struct.pack('BB', OPT_SERVER_ID, 4) + ip_to_bytes(server_ip)
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options += struct.pack('BB', OPT_SUBNET_MASK, 4) + ip_to_bytes(SUBNET_MASK)
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options += struct.pack('BB', OPT_ROUTER, 4) + ip_to_bytes(ROUTER)
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options += struct.pack('BB', OPT_DNS, 4) + ip_to_bytes(ROUTER)
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options += bytes([OPT_LEASE_TIME, 4]) + struct.pack('!I', LEASE_TIME)
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options += bytes([OPT_END])
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return op + htype + hlen + hops + xid + secs + flags + ciaddr + yiaddr + siaddr + giaddr + chaddr + sname + file + magic + options
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def main():
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parser = argparse.ArgumentParser(description="轻量 DHCP Server for CH395F 测试")
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parser.add_argument("--iface", default=SERVER_IP, help="网卡 IP 地址")
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args = parser.parse_args()
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offer_ip = OFFER_IP
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server_ip = args.iface
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sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
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sock.bind(('0.0.0.0', DHCP_SERVER_PORT))
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sock.settimeout(60)
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print(f"DHCP Server 启动, 网卡 IP={server_ip}, 分配 IP={offer_ip}")
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print("等待 CH395F DHCP DISCOVER...")
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try:
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# 第一阶段：DISCOVER → OFFER
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data, addr = sock.recvfrom(4096)
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msg_type = data[232 + 4 + 1] if len(data) > 250 else 0
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client_mac = ':'.join(f'{b:02X}' for b in data[28:34])
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print(f"收到 DHCP DISCOVER from {client_mac}")
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offer = build_dhcp_offer(data, server_ip, offer_ip)
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sock.sendto(offer, ('255.255.255.255', DHCP_CLIENT_PORT))
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print("发送 DHCP OFFER")
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# 第二阶段：REQUEST → ACK
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sock.settimeout(10)
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try:
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data, addr = sock.recvfrom(4096)
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client_mac = ':'.join(f'{b:02X}' for b in data[28:34])
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print(f"收到 DHCP REQUEST from {client_mac}")
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ack = build_dhcp_ack(data, server_ip, offer_ip)
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sock.sendto(ack, ('255.255.255.255', DHCP_CLIENT_PORT))
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print(f"发送 DHCP ACK → {offer_ip}")
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print("DHCP 分配完成！")
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except socket.timeout:
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print("等待 DHCP REQUEST 超时")
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except socket.timeout:
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print("等待 DHCP DISCOVER 超时（60s）")
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finally:
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sock.close()
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if __name__ == '__main__':
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main()
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