Python实现Contiki自组网核心功能

在Python中实现Contiki自组网的功能通常涉及模拟无线传感器网络（WSN）的协议栈、路由机制和节点通信。以下是关键函数和测试用例的详细实现：

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网络节点初始化

class Node:
    def __init__(self, node_id, neighbors=None):
        self.node_id = node_id
        self.neighbors = neighbors if neighbors else []
        self.routing_table = {}  # 格式: {destination: next_hop}

    def add_neighbor(self, neighbor_id):
        if neighbor_id not in self.neighbors:
            self.neighbors.append(neighbor_id)

    def update_routing_table(self, destination, next_hop):
        self.routing_table[destination] = next_hop

测试用例：

def test_node_initialization():
    node = Node(1)
    assert node.node_id == 1
    assert node.neighbors == []
    node.add_neighbor(2)
    assert node.neighbors == [2]
    node.update_routing_table(3, 2)
    assert node.routing_table == {3: 2}

---

路由协议实现（基于RPL）

def build_rpl_dodag(nodes, root_id):
    # 构建RPL的DODAG（面向目的地的有向无环图）
    for node in nodes.values():
        if node.node_id != root_id:
            best_parent = min(node.neighbors, key=lambda x: len(nodes[x].routing_table))
            node.update_routing_table(root_id, best_parent)

测试用例：

def test_rpl_dodag():
    nodes = {
        1: Node(1, [2]),
        2: Node(2, [1, 3]),
        3: Node(3, [2])
    }
    build_rpl_dodag(nodes, root_id=1)
    assert nodes[3].routing_table[1] == 2
    assert nodes[2].routing_table[1] == 1

---

数据包转发

def forward_packet(nodes, source, destination, data):
    current = source
    path = [current]
    while current != destination:
        if destination not in nodes[current].routing_table:
            return None  # 路由失败
        current = nodes[current].routing_table[destination]
        path.append(current)
    return path

测试用例：

def test_forward_packet():
    nodes = {
        1: Node(1, [2]),
        2: Node(2, [1, 3]),
        3: Node(3, [2])
    }
    build_rpl_dodag(nodes, 1)
    path = forward_packet(nodes, 3, 1, "test_data")
    assert path == [3, 2, 1]

---

能量消耗模型

def calculate_energy(nodes, tx_energy=0.1, rx_energy=0.05):
    for node in nodes.values():
        total_energy = len(node.routing_table) * tx_energy + len(node.neighbors) * rx_energy
        node.energy = total_energy

测试用例：

def test_energy_calculation():
    nodes = {1: Node(1, [2]), 2: Node(2, [1])}
    build_rpl_dodag(nodes, 1)
    calculate_energy(nodes)
    assert abs(nodes[1].energy - 0.15) < 1e-6  # 1发送 + 1接收

---

自组网完整测试

def test_network_simulation():
    # 构建4节点网络
    nodes = {i: Node(i) for i in range(1, 5)}
    nodes[1].neighbors = [2]
    nodes[2].neighbors = [1, 3]
    nodes[3].neighbors = [2, 4]
    nodes[4].neighbors = [3]

    # 初始化路由
    build_rpl_dodag(nodes, root_id=1)

    # 验证路由路径
    assert forward_packet(nodes, 4, 1, "data") == [4, 3, 2, 1]

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关键点说明

• RPL协议简化：实际Contiki中RPL包含ETX、OF等复杂计算，此处仅模拟最短路径。
• 能量模型：实际需结合硬件参数（如CC2530的功耗曲线）。
• 扩展性：可集成CoAP、6LoWPAN等协议栈模块。

完整实现需结合Python网络库（如socket或模拟工具pymote），上述代码为核心逻辑的抽象演示。