连接到IPv4地址时拒绝C++winsock连接

Question

我正在使用winsock2编程一个服务器/客户机系统，当我将客户机连接到服务器名称或服务器IPv6地址时，它工作得很好。但是，当我使用服务器IPv4地址时，我从客户端中的connect（）调用中得到错误“Connection referend”。

SOCKET sockfd = INVALID_SOCKET, in_socketID;
struct addrinfo hints;
struct addrinfo *servinfo = NULL;
struct addrinfo *p;
struct addrinfo *ip;
sockaddr_storage incoming_addr;
int addr_size;
int tmp_err;
const char *sPort = "20152";

memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // either IPv4 or IPv6
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;

tmp_err = getaddrinfo(NULL, sPort, &hints, &servinfo);
if (tmp_err != 0)
    throw exception("ERROR: getaddrinfo failed");

// loop through all the results and bind to the first we can
for(p = servinfo; p != NULL && sockfd == INVALID_SOCKET; p = p->ai_next)
{
    ip = p;
    sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
    if (sockfd == INVALID_SOCKET)
    {
        cerr << "ERROR on socket(): " << WSAGetLastError() << endl;
    } // end if
    else if (bind(sockfd, p->ai_addr, p->ai_addrlen) == SOCKET_ERROR)
    {
        cerr << "ERROR on bind(): " << WSAGetLastError() << endl;
        closesocket(sockfd);
        sockfd = INVALID_SOCKET;
    } // end if
} // end for

if (sockfd == INVALID_SOCKET)
{
    // looped off the end of the list with no successful bind
    throw exception("ERROR: Failed to bind socket");
}

// clean up
if (servinfo)
    freeaddrinfo(servinfo);

if (listen(sockfd, SOMAXCONN ) == SOCKET_ERROR)
    throw exception("Listen failed");

while (true)
{
    memset(&incoming_addr, 0, sizeof(incoming_addr));
    addr_size = sizeof(incoming_addr);
    in_socketID = accept(socketID, (sockaddr *)&incoming_addr, &addr_size);

    // do stuff with incoming connection
}

int sockfd = INVALID_SOCKET;
struct addrinfo hints;
struct addrinfo *servinfo = NULL;
struct addrinfo *p;
struct addrinfo *ip;
int tmp_err;
const char *sHost = "192.168.1.136";
const char *sPort = "20152";

memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // either IPv4 or IPv6
hints.ai_socktype = SOCK_STREAM; // use TCP

tmp_err = getaddrinfo(sHost,        // web address or ip to connect to
                      sPort,        // port or protocol
                      &hints,       // initialized hints structure
                      &servinfo);   // return structure
if (tmp_err != 0)
    throw exception("ERROR: getaddrinfo failed");

// loop through all the results and connect to the first we can
for(p = servinfo; p != NULL && sockfd == INVALID_SOCKET; p = p->ai_next)
{
    ip = p;
    sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
    if (sockfd == INVALID_SOCKET)
    {
        cerr << "ERROR on socket(): " << WSAGetLastError() << endl;
        //continue;
    } // end if
    else if (connect(sockfd, p->ai_addr, p->ai_addrlen) < 0)
    {
        cerr << "ERROR on connect(): " << WSAGetLastError() << endl;
        closesocket(sockfd);
        sockfd = INVALID_SOCKET;
        //continue;
    } // end if
} // end for

if (sockfd == INVALID_SOCKET)
    throw exception("ERROR: Failed to connect");


// clean up
if (servinfo)
    freeaddrinfo(servinfo);

// do stuff with new socket

我如何也连接到服务器IPv4地址？我需要帮助，拜托。

多谢了。

根据用户Sorayuki给出的一个建议，我做了一些修改，只是为了检验他的理论是否正确。

hints.ai_family = AF_UNSPEC;

hints.ai_family = AF_INET;

Answer 1

是因为您将服务器套接字绑定到IPv6地址吗？在“for”循环中，出现在IPv4地址之前的IPv6地址似乎会导致服务器的套接字监听IPv6地址。因此您的服务器没有侦听任何IPv4地址,导致所有到服务器IPv4地址的连接都被拒绝。

尝试使用工具或命令（如netstat）查看所有侦听端口在哪个IP地址上