绑定服务器套接字时出现 WSA 错误 10048

Question

我从 msdn 网站上的简单服务器 tutorial 开始学习如何在客户端和服务器应用程序中使用套接字。

完成教程后，我开始将客户端和服务器代码调整为多线程程序，以制作 tchat 客户端和服务器。一切都很顺利，直到我运行进入 WSA 错误 10048。我尝试为每个套接字使用不同的端口，但它仍然没有解决错误。

这是我的服务器代码：

#undef UNICODE

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <thread>
#include <vector>

// Need to link with Ws2_32.lib
#pragma comment (lib, "Ws2_32.lib")
// #pragma comment (lib, "Mswsock.lib")

//Global values
//I put them as global values in order to get the server up and running.
//I will try to pass them as params later on
int iResult;
struct addrinfo *result = NULL;
struct addrinfo hints;
int numClients = 0;
SOCKET ClientSocket[5];
std::thread** sendReceiveThread = new std::thread*[5];

//Prototypes
int listen(SOCKET ListenSocket);
int accept(SOCKET ListenSocket);
int sendReceive();
int shutdownFunction(SOCKET ClientSocket);

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT1 "1016"
#define DEFAULT_PORT2 "1017"
#define DEFAULT_PORT3 "1018"
#define DEFAULT_PORT4 "1019"
#define DEFAULT_PORT5 "1020"

int main()
{
    std::cout << 1 << std::endl;
    WSADATA wsaData;

    SOCKET ListenSocket = INVALID_SOCKET;


    // Initialize Winsock
    std::cout << 2 << std::endl;
    iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0) {
        std::cout << 3 << std::endl;
        printf("WSAStartup failed with error: %d\n", iResult);
        return 1;
    }

    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = AI_PASSIVE;

    std::thread ListenThread{ [ListenSocket](){listen(ListenSocket); } };
    ListenThread.join();

    return 0;
}

int listen(SOCKET ListenSocket)
{
    int numPort = 1;
    std::vector<std::thread*> thread_vec;
    while (true)
    {
        if (numPort == 1)
        {
            // Resolve the server address and port
            std::cout << 4 << std::endl;
            iResult = getaddrinfo(NULL, DEFAULT_PORT1, &hints, &result);
            numPort++;
            if (iResult != 0) {
                std::cout << 5 << std::endl;
                printf("getaddrinfo failed with error: %d\n", iResult);
                WSACleanup();
                break;
            }
        }

        else if (numPort == 2)
        {
            // Resolve the server address and port
            std::cout << 4 << std::endl;
            iResult = getaddrinfo(NULL, DEFAULT_PORT2, &hints, &result);
            numPort++;
            if (iResult != 0) {
                std::cout << 5 << std::endl;
                printf("getaddrinfo failed with error: %d\n", iResult);
                WSACleanup();
                break;
            }
        }

        else if (numPort == 3)
        {
            // Resolve the server address and port
            std::cout << 4 << std::endl;
            iResult = getaddrinfo(NULL, DEFAULT_PORT3, &hints, &result);
            numPort++;
            if (iResult != 0) {
                std::cout << 5 << std::endl;
                printf("getaddrinfo failed with error: %d\n", iResult);
                WSACleanup();
                break;
            }
        }

        else if (numPort == 4)
        {
            // Resolve the server address and port
            std::cout << 4 << std::endl;
            iResult = getaddrinfo(NULL, DEFAULT_PORT4, &hints, &result);
            numPort++;
            if (iResult != 0) {
                std::cout << 5 << std::endl;
                printf("getaddrinfo failed with error: %d\n", iResult);
                WSACleanup();
                break;
            }
        }

        else if (numPort == 5)
        {
            // Resolve the server address and port
            std::cout << 4 << std::endl;
            iResult = getaddrinfo(NULL, DEFAULT_PORT5, &hints, &result);
            numPort++;
            if (iResult != 0) {
                std::cout << 5 << std::endl;
                printf("getaddrinfo failed with error: %d\n", iResult);
                WSACleanup();
                break;
            }
        }

        // Create a SOCKET for connecting to server
        std::cout << 6 << std::endl;
        ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
        if (ListenSocket == INVALID_SOCKET) {
            std::cout << 7 << std::endl;
            printf("socket failed with error: %ld\n", WSAGetLastError());
            freeaddrinfo(result);
            WSACleanup();
            break;
        }

        // Setup the TCP listening socket
        std::cout << 8 << std::endl;
        iResult = bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
        if (iResult == SOCKET_ERROR) {
            std::cout << 9 << std::endl;
            printf("bind failed with error: %d\n", WSAGetLastError());
            freeaddrinfo(result);
            closesocket(ListenSocket);
            WSACleanup();
            break;
        }

        freeaddrinfo(result);

        std::cout << 10 << std::endl;
        iResult = listen(ListenSocket, SOMAXCONN);
        if (iResult == SOCKET_ERROR) {
            std::cout << 11 << std::endl;
            printf("listen failed with error: %d\n", WSAGetLastError());
            closesocket(ListenSocket);
            WSACleanup();
            break;
        }


        static std::thread AcceptThread{ [ListenSocket](){accept(ListenSocket); } };
        thread_vec.push_back(&AcceptThread);
    }
    for (auto it : thread_vec) it->join();
    return 0;
}

int accept(SOCKET ListenSocket)
{
    numClients++;
    const int currentNumClients = numClients;
    for (int i = 0; i <= 5; i++)
    {
        ClientSocket[i] = INVALID_SOCKET;
    }

    // Accept a client socket
    std::cout << 12 << std::endl;

    std::cout << 13 << std::endl;

    ClientSocket[currentNumClients] = accept(ListenSocket, NULL, NULL);
    if (ClientSocket[currentNumClients] == INVALID_SOCKET)
    {
        printf("accept failed with error: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    sendReceiveThread[currentNumClients] = new std::thread([](){sendReceive(); });
    (*sendReceiveThread[currentNumClients]).join();
    delete sendReceiveThread[currentNumClients];

    return 0;
}

int sendReceive()
{
    int currentNumClients = numClients;
    int iSendResult;
    char recvbuf[DEFAULT_BUFLEN];
    int recvbuflen = DEFAULT_BUFLEN;

    // Receive until the peer shuts down the connection
    while(true)
    {
        std::cout << 14 << std::endl;
        iResult = recv(ClientSocket[currentNumClients], recvbuf, recvbuflen, 0);
        std::cout << iResult << std::endl;
        if (iResult > 0) {
            std::cout << 15 << std::endl;
            printf("Bytes received: %d\n", iResult);

            // Echo the buffer back to the clients
            std::cout << 16 << std::endl;
            for (int i = 1; i <= numClients; i++)
            {
                iSendResult = send(ClientSocket[currentNumClients], recvbuf, iResult, 0);
                if (iSendResult == SOCKET_ERROR) {
                    std::cout << 17 << std::endl;
                    printf("send failed with error: %d\n", WSAGetLastError());
                    closesocket(ClientSocket[currentNumClients]);
                    WSACleanup();
                    return 1;
                }
                printf("Bytes sent: %d\n", iSendResult);
            }
        }
        else if (iResult == 0) {
            std::cout << 18 << std::endl;
            printf("Connection closing...\n");
            break;
        }
        else {
            std::cout << 19 << std::endl;
            printf("recv failed with error: %d\n", WSAGetLastError());
            std::cout << "On client #" << currentNumClients << std::endl;
            break;
        }

    }

    iResult = shutdownFunction(ClientSocket[currentNumClients]);

    std::cout << 22 << std::endl;
    // cleanup
    closesocket(ClientSocket[currentNumClients]);
    WSACleanup();

    return 0;
}

int shutdownFunction(SOCKET ClientSocket)
{
    std::cout << 20 << std::endl;
    iResult = shutdown(ClientSocket, SD_SEND);
    if (iResult == SOCKET_ERROR) {
        std::cout << 21 << std::endl;
        printf("shutdown failed with error: %d\n", WSAGetLastError());
        closesocket(ClientSocket);
        WSACleanup();
        return 1;
    }

    return 0;
}

您可能会注意到不同的 cout，这些只是了解程序行为的 cout。

Answer 1

WSA 10048 是 'Address in use' 错误 (https://msdn.microsoft.com/en-us/library/windows/desktop/ms740668(v=vs.85).aspx)。

我没有 windows 所以我不能运行你的代码，但是这个错误通常发生在服务器将服务器端口保留几分钟之后才可以重复使用。

提供套接字选项以允许更快的重用，setsockopt (SO_REUSEADDR)。

在您的情况下，您将在创建并检查 ListenSocket 后立即添加以下行：

int optval = 1;
iResult = ::setsockopt(ListenSocket, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof optval);

if (iResult == SOCKET_ERROR) {
        std::cout << 9 << std::endl;
        printf("setsockopt failed with error: %d\n", WSAGetLastError());
}

TCP 堆栈有充分的理由不在旧端口号发布后立即重新发布它们，但对于服务器端口来说，这是不受欢迎的行为。只是，栈不知道服务器端口和非服务器端口的区别，所以我们必须使用setsockopt。

绑定服务器套接字时出现 WSA 错误 10048

WSA error 10048 when binding server sockets

c++

sockets

multithreading

winsock2

windows-socket-api