doip的routing activation request如何封装发送，提供一段python代码

### 封装并发送DOIP路由激活请求 为了使用Python封装并发送DOIP的路由激活请求，可以创建一个专门处理此类操作的类或函数。下面是一个简单的例子来展示如何构建和发送这样的请求。 #### 构建Routing Activation Request 根据协议规定，在建立TCP连接之后，但在实际的数据交换之前，客户端应当向服务器发出路由激活请求以完成必要的初始化过程[^3]。此请求用于将源逻辑地址与特定套接字绑定在一起，从而允许后续的消息传递活动正常进行。 ```python import struct from socket import socket, AF_INET, SOCK_STREAM class DoIpClient: def __init__(self, server_ip, port): self.server_address = (server_ip, port) self.sock = None def connect(self): """Establish a TCP connection to the DOIP server.""" try: sock = socket(AF_INET, SOCK_STREAM) sock.connect(self.server_address) self.sock = sock except Exception as e: print(f"Failed to establish connection: {e}") @staticmethod def create_routing_activation_request(source_logical_addr): """ Create a RoutingActivationRequest message according to ISO 13400-2. :param source_logical_addr: Source logical address of ECU requesting activation. :return: bytes object containing formatted request payload. """ protocol_version = b'\x02' # Version number defined by standard inverse_protocol_version = b'\xFD' payload_type_id = b'\x00\x08' # Type ID for routing activation request reserved_field = b'\x00'*7 # Reserved fields set to zero per specification security_access_level = b'\x00' data_length_format_identifier = b'\xFF' # Indicates no additional data follows target_address_information = b'' # Empty since we're not specifying targets here return ( protocol_version + inverse_protocol_version + payload_type_id + struct.pack('!H', len(reserved_field)+len(security_access_level))+ reserved_field + security_access_level + data_length_format_identifier + target_address_information ) ``` 这段代码定义了一个`DoIpClient`类，其中包含了用来创建路由激活请求的方法。该方法接收源逻辑地址作为参数，并按照ISO标准格式化成相应的二进制数据流。 #### 发送Routing Activation Request 一旦建立了到目标设备的TCP连接并且准备好了要发送的内容，则可以通过调用如下所示的方法来进行消息传输： ```python def send_routing_activation_request(client_instance, src_logic_addr): req_msg = client_instance.create_routing_activation_request(src_logic_addr) if client_instance.sock is None or not isinstance(client_instance.sock, socket): raise ValueError("Socket has not been properly initialized.") sent_bytes = client_instance.sock.send(req_msg) if sent_bytes != len(req_msg): raise RuntimeError("Failed to fully transmit routing activation request.") # Example usage with hypothetical IP and port values along with an example source logic address if __name__ == "__main__": doip_client = DoIpClient(server_ip="192.168.1.10", port=13400) doip_client.connect() send_routing_activation_request(doip_client, "0xABCDEF") # Replace this string with actual hex value representing your source addr ``` 上述脚本展示了如何实例化`DoIpClient`对象并与远程主机建立联系；随后它会尝试发送由`create_routing_activation_request()`生成的消息体给对方节点。请注意替换示例中的IP地址、端口号以及源逻辑地址为适用于您环境的具体数值。