Question

尝试创建一个简单的WinSock服务器 - accept（）只是保持返回204.204.204.204的IP。我的在线搜索结果显示很多人因为没有给出sockaddr长度（第3次接受（）参数而得到此错误，但我已经是。

已经挣扎了很长时间;我毫不怀疑我犯了一个简单的错误，但我无法发现它！

PS。我知道我传递了一些未使用的变量和东西 - 正在进行中的工作：）

Network.h :::

#pragma once
#include <afxwin.h>
#include <string>
#include <Windows.h>
#include <functional>
#include <WinSock2.h>
#include <iostream>
#include "Connection.h"
using namespace std;

#define LISTEN_PORT 20248
#define MAX_CLIENTS 10

typedef struct NETWORK_T
{
    SOCKET c_socket;            // Client Socket
    sockaddr_in addr_in;        // Addr_in
    fd_set set;                 // Used to check if data in socket
    int i;                      // Additional info
} CLIENT, SERVER;

class Network
{
public:
    Network(void);
    ~Network(void);
    void StartListenServer(string port, function<void(Connection)> callback);
    void StopListenServer(void);
    void Connect(string ip, string port);

private:
    bool mServerRunning;
    WSADATA mData;
    SERVER* mServer;

    static UINT ServerThread(LPVOID pParam);

    bool Setup(SERVER* server, WSADATA& data);
    void ServerCloseSocket(NETWORK_T* socket);
    void ServerCloseSocket(SOCKET& socket);
};

Network.CPP :::

#include "Network.h"


Network::Network(void)
{
    mServerRunning = false;
}


Network::~Network(void)
{

}

void Network::StartListenServer(string port, function<void(Connection)> callback)
{
    if(mServerRunning)
        return;         // If server is running we dont want a second

    mServerRunning = true;
    AfxBeginThread(ServerThread, this);
}

void Network::StopListenServer(void)
{
    mServerRunning = false;
}

void Network::Connect(string ip, string port)
{

}

void Network::ServerCloseSocket(NETWORK_T* socket)
{
    shutdown(socket->c_socket, 2);
    closesocket(socket->c_socket);
}

void Network::ServerCloseSocket(SOCKET& socket)
{
    shutdown(socket, 2);
    closesocket(socket);
}

bool Network::Setup(SERVER* server, WSADATA& data)
{
    int res;

    server->addr_in.sin_family = AF_INET;
    server->addr_in.sin_port = htons(LISTEN_PORT);
    server->addr_in.sin_addr.s_addr = htonl(INADDR_ANY);
    res = WSAStartup(0x101, &data);
    if (res != 0)
    {
        cout << "WSAStartup failed.\r\n";
        return false;
    }
    else
    {
        cout << "WSAStartup Version: " << data.wVersion << "\nWSADescription: " << data.szDescription << "\nWSAStatus: " << data.szSystemStatus << "\r\n";
    }
    server->c_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (server->c_socket == INVALID_SOCKET)
    {
        cout << "Invalid socket.\r\n";
        return false;
    }
    else if (server->c_socket == SOCKET_ERROR)
    {
        cout << "Socket error.\r\n";
        return false;
    }
    else
        cout << "Server socket established.\r\n";
    res = 1;
    setsockopt(server->c_socket, SOL_SOCKET, SO_REUSEADDR, (char*)&res, sizeof(res));   // Allows the socket to be bound to an address that is already in use
    res = ::bind(server->c_socket, (struct sockaddr*)&server->addr_in, sizeof(struct sockaddr));
    if (res != 0)
    {
        cout << "Socket BIND failed.\r\n";
        return false;
    }
    else
        cout << "Socket bound to port " << LISTEN_PORT << "\r\n";
    res = listen(server->c_socket, MAX_CLIENTS);
    cout << "Server listen mode: " << res << "\nMax clients: " << MAX_CLIENTS << "\r\n";
    res = 1;
    ioctlsocket(server->c_socket, FIONBIO, (u_long*)&res);

    return true;
}

UINT Network::ServerThread(LPVOID pParam)
{
    Network* ntwkPtr = (Network*)pParam;

    ntwkPtr->mServer = new SERVER();

    ntwkPtr->Setup(ntwkPtr->mServer, ntwkPtr->mData);

    SOCKET client;
    SOCKADDR_IN from;
    int fromlen = sizeof(from);

    while(ntwkPtr->mServerRunning)
    {
        char temp[512];
        client = accept(ntwkPtr->mServer->c_socket, (struct sockaddr*)&from, &fromlen); 
        sprintf(temp,"Your IP is %s\r\n",inet_ntoa(from.sin_addr));
        send(client,temp,strlen(temp),0);
        cout << "Connection from " << inet_ntoa(from.sin_addr) <<"\r\n";
        //ntwkPtr->ServerCloseSocket(client);
    }

    ntwkPtr->ServerCloseSocket(ntwkPtr->mServer);
    WSACleanup();

    return 0;
}

Answer 1

同样见于this PCReview thread，这个问题是由于在长度字段中将不正确的值传递给accept而导致的。在线程的情况下，这是一个空值，在你的情况下，~~是一个内存地址（&fromlen）。~~

~~要修复此问题，请从fromlen删除“地址”操作符。~~

作为一个兴趣点，以及来自PCReview线程，其原因是：

204是0xCC，这是编译器使用的值调试版本中未初始化的堆栈变量有助于捕获错误访问。由于您传递了NULL，因此没有返回任何内容，还有sockAddrIn 没有初始化。

修改

正如您所提到的，它是一个指针参数。为了感兴趣，我会在这里留下其余的答案。

Answer 2

在评论中确认：accept失败，因此无法报告地址。

WinSock accept（）返回204.204.204.204

2 个答案:

修改