Transport Layer - ISO 15765 (CAN) & DoIP

#!/usr/bin/env python3
# DoIP routing activation: required before sending UDS over Ethernet
import socket, struct

DOIP_PROTO_VER   = 0xFF
DOIP_INVERT_VER  = 0xFE
DOIP_ROUTING_ACT_REQ  = 0x0005
DOIP_ROUTING_ACT_RESP = 0x0006
DOIP_UDS_REQ     = 0x8001
DOIP_UDS_RESP    = 0x8001

def doip_header(payload_type: int, payload: bytes) -> bytes:
    return struct.pack(">BBHI", DOIP_PROTO_VER, DOIP_INVERT_VER,
                       payload_type, len(payload)) + payload

def routing_activate(sock, source_addr=0xE00):
    payload = struct.pack(">HBxxxxxx", source_addr, 0x00)  # activation type 0x00 = default
    sock.send(doip_header(DOIP_ROUTING_ACT_REQ, payload))
    resp = sock.recv(256)
    # Parse response: payload type 0x0006
    ptype = struct.unpack(">H", resp[2:4])[0]
    if ptype == DOIP_ROUTING_ACT_RESP:
        rcode = resp[12]  # routing activation response code
        if rcode == 0x10:
            print("Routing activation: SUCCESS (0x10)")
            return True
        else:
            print(f"Routing activation FAILED: code=0x{rcode:02X}")
    return False

def send_uds(sock, target_addr: int, uds_payload: bytes) -> bytes:
    payload = struct.pack(">HH", 0xE000, target_addr) + uds_payload
    sock.send(doip_header(DOIP_UDS_REQ, payload))
    resp = sock.recv(4096)
    return resp[12:]  # skip 8-byte DoIP header + 4-byte source/target

sock = socket.create_connection(("192.168.1.100", 13400), timeout=5)
if routing_activate(sock):
    response = send_uds(sock, 0x0726, bytes([0x22, 0xF1, 0x90]))
    print(f"VIN response: {response.hex()}")