ネットワーク上のデバイスへの接続に問題があります。getaddrinfo() を呼び出すたびに、11001 が返されます。IP_ADDRESS 文字列 (Global Var) 内の多数の異なる IP でこれを確認しました。nslookup ですべての非稼働番号を確認しましたが、ほとんどがそこに存在します。
getaddrinfo-returns-always-11001-host-not-found も同様の質問をしているようですが、そこには答えがありません。
現時点では、私のコードはリモート デバイスに接続しようとしてもおらず、IP を解決しようとしているだけです。それが機能したら、より大きくて厄介な問題に進むことができます。
実装：
int connectToDevice(char *sendbuf, char *recvbuf, SOCKET ConnectSocket)
{
WSADATA wsaData;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
struct timeval tval;
fd_set rset, wset;
int iResult;
u_long mode = -1;
//Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0)
{
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
//Resolve the server address and port
iResult = getaddrinfo(IP_ADDRESS, DEFAULT_PORT, &hints, &result);
if ( iResult != 0 )
{
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Attempt to connect to an address until one succeeds
for(ptr=result; ptr != NULL ;ptr=ptr->ai_next)
{
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET)
{
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
//set socket to non-blocking
iResult = ioctlsocket(ConnectSocket, FIONBIO, &mode); //if mode is set to non-zero, socket set to non-blocking.
if(iResult != NO_ERROR)
{
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
// Connect to server.
iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR ) //if an error and not WSAEWOULDBLOCK, then close socket and try next address
{
if(WSAEWOULDBLOCK != WSAGetLastError())
{
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue; //this returns control to the For loop. I.e. if a socket error, try next address
}
else //otherwise if the error was WSAEWOULDBLOCK, then use select to check for connections.
{
FD_ZERO(&rset); //initialise fd_sets for reading and writing; both the same.
FD_SET(ConnectSocket, &rset);
wset = rset;
//set tval to timeout value
tval.tv_sec = TIMEOUT;
tval.tv_usec= 0;
//select statement
//select ignores first parameter
//select takes 3xfd_sets, read set, write set, and exception set.
//select's last parameter is timeout in the form of a timeval struct
//if return == 0, timeout occured.
//if return == SOCKET_ERROR, error occured, use WSAGetLastError to check for details.
iResult = select(ConnectSocket, &rset, &wset, NULL, &tval);
if (iResult ==0)
{
closesocket(ConnectSocket);
printf("Timeout reached, closing socket");
WSACleanup();
return 1;
}
else if(iResult == SOCKET_ERROR)
{
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
}
}
break; //Breaks out of the for loop. Will only occur if continue not executed
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET)
{
printf("Unable to connect to server!\n");
WSACleanup();
return 1;
}
return 0;}
このコードのほとんどは、msdn の Web サイトからロックとストックを取得したものですが、すべて問題ないように見えます。