计算机网络实验内部网关协议——RIPc++vs2022代码实现

很高兴能够回答你的问题。RIP（Routing Information Protocol）是一个内部网关协议，它用于在同一组织的网络中传递路由信息。RIP使用距离向量算法来确定最佳路径，并且具有自适应性，可以自动调整网络拓扑变化。

以下是RIP的C++代码实现：

#include <iostream>
#include <vector>
#include <string>
#include <limits.h>
#include <algorithm>
#include <unordered_map>

using namespace std;

// 定义路由表项
struct RoutingTableEntry {
    string destination;  // 目标网络IP地址
    int hopCount;        // 经过的跳数
    string nextHop;      // 下一跳路由器IP地址
};

// 实现路由器节点
class Router {
public:
    Router(string routerId) {
        id = routerId;
    }

    // 添加相邻路由器
    void addNeighbor(Router* neighbor, int cost) {
        neighbors[neighbor] = cost;
    }

    // 更新路由表
    void updateRoutingTable() {
        routingTable.clear();
        unordered_map<string, int> distanceVector;
        distanceVector[id] = 0;

        // 初始化距离向量
        for (auto& neighbor : neighbors) {
            distanceVector[neighbor.first->id] = neighbor.second;
        }

        // 迭代更新距离向量
        bool updated = true;
        while (updated) {
            updated = false;
            for (auto& neighbor : neighbors) {
                unordered_map<string, int> neighborVector = neighbor.first->getDistanceVector();
                for (auto& item : neighborVector) {
                    if (item.first == id) {
                        continue;
                    }

                    int distance = neighbor.second + item.second;
                    if (distance < distanceVector[item.first]) {
                        distanceVector[item.first] = distance;
                        updated = true;
                    }
                }
            }
        }

        // 生成路由表
        for (auto& item : distanceVector) {
            if (item.first == id) {
                continue;
            }

            int minCost = INT_MAX;
            Router* minNeighbor = nullptr;
            for (auto& neighbor : neighbors) {
                if (neighbor.first->id == item.first) {
                    minCost = neighbor.second;
                    minNeighbor = neighbor.first;
                    break;
                }

                unordered_map<string, int> neighborVector = neighbor.first->getDistanceVector();
                auto iter = neighborVector.find(item.first);
                if (iter != neighborVector.end() && neighbor.second + iter->second < minCost) {
                    minCost = neighbor.second + iter->second;
                    minNeighbor = neighbor.first;
                }
            }

            RoutingTableEntry entry;
            entry.destination = item.first;
            entry.hopCount = minCost;
            entry.nextHop = minNeighbor->id;
            routingTable.push_back(entry);
        }
    }

    // 获取距离向量
    unordered_map<string, int> getDistanceVector() {
        unordered_map<string, int> distanceVector;
        for (auto& neighbor : neighbors) {
            distanceVector[neighbor.first->id] = neighbor.second;
        }
        return distanceVector;
    }

    // 打印路由表
    void printRoutingTable() {
        cout << "Routing table of router " << id << ":" << endl;
        cout << "Destination\tHop count\tNext hop" << endl;
        for (auto& entry : routingTable) {
            cout << entry.destination << "\t\t" << entry.hopCount << "\t\t" << entry.nextHop << endl;
        }
        cout << endl;
    }

private:
    string id;  // 路由器ID
    unordered_map<Router*, int> neighbors;  // 相邻路由器和其距离
    vector<RoutingTableEntry> routingTable;  // 路由表
};

int main() {
    // 创建四个路由器节点
    Router* r1 = new Router("R1");
    Router* r2 = new Router("R2");
    Router* r3 = new Router("R3");
    Router* r4 = new Router("R4");

    // 添加相邻路由器和距离
    r1->addNeighbor(r2, 2);
    r1->addNeighbor(r3, 1);
    r2->addNeighbor(r1, 2);
    r2->addNeighbor(r3, 3);
    r2->addNeighbor(r4, 1);
    r3->addNeighbor(r1, 1);
    r3->addNeighbor(r2, 3);
    r3->addNeighbor(r4, 2);
    r4->addNeighbor(r2, 1);
    r4->addNeighbor(r3, 2);

    // 更新路由表
    r1->updateRoutingTable();
    r2->updateRoutingTable();
    r3->updateRoutingTable();
    r4->updateRoutingTable();

    // 打印路由表
    r1->printRoutingTable();
    r2->printRoutingTable();
    r3->printRoutingTable();
    r4->printRoutingTable();

    return 0;
}

上述代码实现了一个简单的RIP路由器，它可以自动计算最佳路径并生成路由表。需要注意的是，该实现并不完整，仅仅是提供了一个基本的框架，如果需要实际使用，还需要进行更多的改进和优化。