IPv6客户端无法连接到IPv6服务器

Question

我的程序是客户端服务器IPv6。客户端无法建立与服务器的连接？客户端和服务器必须使用回送地址此代码中的问题，它无法连接到服务器

   SOCKET sock = socket(AF_INET6, SOCK_STREAM, 0);
 if (sock == INVALID_SOCKET)
  {
    cerr << "Can't create socket, Err #" << WSAGetLastError() << endl;
    WSACleanup();
    return;
 }

   sockaddr_in6 hint;
hint.sin6_family = AF_INET6;
hint.sin6_port = htons(port);
hint.sin6_addr = in6addr_any;
// Connect to server
int connResult = connect(sock, (sockaddr*)&hint, sizeof(hint));
if (connResult == SOCKET_ERROR)
{
    cerr << "Can't connect to server, Err #" << WSAGetLastError() 
   << endl;
    closesocket(sock);
    WSACleanup();
    return;
}

Answer 1

客户端TCP套接字不能connect()至in6addr_any。 TCP服务器可以从bind()到in6addr_any，因此可以通过单个listen()在所有可用的本地IPv6网络接口上进行SOCKET。但是客户端必须connect()到服务器实际监听的真实IPv6地址（例如，如果客户端与服务器在同一台计算机上运行，​​则为in6addr_loopback。服务器可以使用GetAdaptersInfo()或GetAdaptersAddresses()发现对客户端connect()而言有效的本地IP地址实际是什么。

此外，您需要将sockaddr_in6结构完全归零。 sockaddr_in6具有未填充的sin6_flowinfo和sin6_scope_id字段，因此它们将具有来自堆栈的随机值。 sin6_scope_id特别会影响connect()使用正确的网络接口连接到服务器的能力。

SOCKET sock = socket(AF_INET6, SOCK_STREAM, 0);
if (sock == INVALID_SOCKET)
{
    cerr << "Can't create socket, Err #" << WSAGetLastError() << endl;
    WSACleanup();
    return;
}

sockaddr_in6 hint = {};
hint.sin6_family = AF_INET6;
hint.sin6_port = htons(port);
inet_pton(AF_INET6, "server IPv6 address here", &(hint.sin6_addr));

// Connect to server
int connResult = connect(sock, (sockaddr*)&hint, sizeof(hint));
...

考虑改为使用getaddrinfo()。让操作系统为您分配一个适当填充的sockaddr_in6，然后您可以按原样将其传递给connect()（类似于我在previous question中为bind()向您解释的方式）。

addrinfo hint = {};
hint.ai_family = AF_INET6;
hint.ai.socktype = SOCK_STREAM;
hint.ai_protocol = IPPROTO_TCP;

addrinfo *res;

err = getaddrinfo("server hostname or IPv6 address here", "server port here", &hint, &res);
if (err != 0)
{
    cerr << "Can't get address to connect, Err #" << WSAGetLastError() << endl;
    WSACleanup();
    return;
}

SOCKET sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sock == INVALID_SOCKET)
{
    cerr << "Can't create socket, Err #" << WSAGetLastError() << endl;
    freeaddrinfo(res);
    WSACleanup();
    return;
}

// Connect to server
int connResult = connect(sock, res->ai_addr, res->ai_addrlen);
if (connResult == SOCKET_ERROR)
{
    cerr << "Can't connect to server, Err #" << WSAGetLastError() << endl;
    closesocket(sock);
    freeaddrinfo(res);
    WSACleanup();
    return;
}

freeaddrinfo(res);
...