我正在编写一个Socket库,我遇到了绑定到特定地址和端口的客户端套接字的问题。我正在测试我的winsock TCP库,虽然我确定我没有理由在* nix上遇到同样的问题。到目前为止一切正常(如果我connect()
没有先致电bind()
我可以send()
和recv()
)。
我有一台服务器正在侦听192.168.1.99:XXXX(我机器的地址)。
然后我得到一个套接字并绑定到192.168.1.99:0。我尝试连接时收到套接字错误10049(WSAEADDRNOTAVAIL
)。如果我尝试绑定到0.0.0.0:0,就会发生同样的事情。
如果我尝试绑定到127.0.0.1:0或localhost或将主机名保留为NULL(如果这是可能的话,我应该使用AI_PASSIVE标志吗?)然后连接我得到10061(WSACONNREFUSED
)。
有人知道这样做的正确方法吗?
EDIT3:结果问题是我在调用bind之前调用socket,然后在调用connect之前再次调用它。我在调用bind之前将它切换到只调用套接字。我不知道是否有其他人对这整个概念感到困惑,所以除非有人认为应该关闭,否则我会把它留在这里?
编辑2:我的插座是两次问题吗?
编辑:以下是一些功能
int main() {
WSADATA wsaData; // if this doesn't work
if(WSAStartup(MAKEWORD(2,0), &wsaData) != 0) {
cout << WSAStartup failed << endl;
return -1;
}
ClientSocket* cs = new ClientSocket("192.168.1.99", "XXXX");
cs->bind("", "0"); //error 10049 (WSAEADDRNOTAVAIL)
//cs->bind("", "60000"); //error 10049 (WSAEADDRNOTAVAIL)
//cs->bind("0.0.0.0", "0"); //error 10049 (WSAEADDRNOTAVAIL)
//cs->bind("0.0.0.0", "60000"); //error 10049 (WSAEADDRNOTAVAIL)
//cs->bind("192.168.1.99", "0"); //error 10061 (WSACONNREFUSED)
//cs->bind("192.168.1.99", "60000"); //error 10061 (WSACONNREFUSED)
//cs->bind("127.0.0.1", "0"); //error 10061 (WSACONNREFUSED)
//cs->bind("127.0.0.1", "60000"); //error 10061 (WSACONNREFUSED)
//cs->bind("localhost", "0"); //error 10061 (WSACONNREFUSED)
//cs->bind("localhost", "60000"); //error 10061 (WSACONNREFUSED)
cs->connect(); //connects to the info passed in ctor
Socket* s = cs->getSocket();
if(s == NULL) {
cs->close();
return -1;
}
.
.
.
.
}
//these are the methods exposed by my API
int ClientSocket::bind(std::string hostname, std::string port) {
if(bound) {
return -1;
}
if(connected) {
return -2;
}
//this defines what specialSockOp will do
ssop = &ClientSocket::BaseDef::bind;
info->hostname = hostname;
if(hostname.compare("") == 0) {
info->AI_FLAG_PASSIVE = true;
}
info->port = port;
//calls SpecialSocket::socket()
socket();
bound = true;
return 0;
}
int ClientSocket::connect() {
if(connected) {
return SOCKET_ERROR;
//throw exception
}
if(bound) {
ssop = &ClientSocket::BaseDef::connect;
}
socket();
return 0;
}
void SpecialSocket::WinImp::socket() {
struct addrinfo *results = NULL, *p = NULL, hints;
int rv;
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = (containerClass->info->ipType == IP_DUAL ? AF_UNSPEC :
containerClass->info->ipType == IPV6 ? AF_INET6 : AF_INET);
hints.ai_socktype = (containerClass->info->protocol == TCP ? SOCK_STREAM :
SOCK_DGRAM);
hints.ai_protocol = 0;
if(containerClass->info->AI_FLAG_PASSIVE) {
hints.ai_flags |= AI_PASSIVE;
}
if(containerClass->info->AI_FLAG_CANONNAME) {
hints.ai_flags |= AI_CANONNAME;
}
//cStringHostname returns NULL if an empty string has been passed in
if((rv = getaddrinfo(containerClass->info->cStringHostname(),
containerClass->info->cStringPort(), &hints, &results)) != 0) {
//throw exception
}
for(p = results; p != NULL; p = p->ai_next) {
if((containerClass->info->sock_fd = ::socket(p->ai_family,
p->ai_socktype, p->ai_protocol)) == INVALID_SOCKET) {
closesocket(containerClass->info->sock_fd);
continue;
}
//for a ClientSocket specialSockOp will call either bind or connect
//corresponding to the function called by ClientSocket
if(containerClass->specialSockOp(p->ai_addr) == SOCKET_ERROR) {
closesocket(containerClass->info->sock_fd);
continue;
}
break; //successfully connected
}
if(p == NULL) {
//none of the connections in results were good
//throw exception - could not connect
}
freeaddrinfo(results);
}
int SpecialSocket::WinImp::bind(const void* addr) {
struct sockaddr* ai_addr = (struct sockaddr*)addr;
return ::bind(containerClass->getSockFd(), ai_addr, sizeof(*ai_addr));
}
int ClientSocket::WinImp::connect(const void* addr) {
struct sockaddr* ai_addr = (struct sockaddr*)addr;
int result = ::connect(containerClass->getSockFd(), ai_addr, sizeof(*ai_addr));
if(result == SOCKET_ERROR) {
//these are where my errors are showing up
cout << "error after connect() is - " << WSAGetLastError() << endl;
return SOCKET_ERROR;
}
containerClass->servInfo->sock_fd = containerClass->getSockFd();
//I separated the functionality here - Socket can only send/recv
containerClass->s = new Socket();
//I use getpeername here to get information about the remote socket
//Long story but basically sets up the Socket
containerClass->initRWSocket(containerClass->s, containerClass->servInfo);
return result;
}
然后,用户可以致电ClientSocket.getSocket()
,然后返回Socket
,然后他们才能send/recv
开启。在我的情况下,这是返回NULL
,因为Socket
从未实例化,因为SpecialSocket::connect
在它执行之前返回。
答案 0 :(得分:3)
您必须绑定到能够连接到connect的目标地址的有效本地地址,即具有到它的路由。显然在这种情况下:
这是绑定活动套接字是个坏主意的几个原因之一:在多宿主主机中,您必须迭代本地地址以选择合适的主机,即复制TCP将自动为您执行的路由。你根本没有做bind()。
编辑中给出的解释与您得到的错误不一致。