Server closes connection before replying - c

Question

I'm following the MSDN lessons about TCP/IP client; my issue is that the server isn't replying and the connection closes after I send the Headers.
const char *USR_PORT = "80";
#define BUFF_LEN 512
char recv_buf[BUFF_LEN];
const char HEADER_TO_SEND[] = "HEAD / HTTP/1.1\r\nHost: www.microsoft.com\r\nUser-Agent: RequestHeaderC\r\n\r\n";
{...}
do {
iRes = recv(ConnSocket, recv_buf, BUFF_LEN, 0);
if (iRes > 0)
{
printf("Bytes received: %d\n", iRes);
for (i = 0; (i < iRes) && recv_buf[i] != '\0'; i++)
printf("%c", recv_buf[i]);
}
else if (iRes == 0)
printf("Connection closed by the server.\n");
else printf("Error: %d\n", WSAGetLastError());
} while (iRes > 0);
I'm almost sure the connection was fine as I sent with success the bytes.
I don't receive any byte at all.
The other codes are almost the same as the ones in the tutorial, that's why I haven't posted them. If needed, I will
The server doesn't close the connection immediately if I remove this line:
shutdown(ConnSocket, SD_SEND);
But then I don't get any answer anyways, even if I add
Connection: close\r\n
in the headers
Full code:
const char *USR_PORT = "80";
#define BUFF_LEN 512
char USR_ADDR[] = "www.microsoft.com";
const char HEADER_TO_SEND[] = "HEAD / HTTP/1.1\r\nHost: www.microsoft.com\r\nUser-Agent: RequestHeaderC\r\nConnection: close\r\n\r\n";
int main()
{
WSADATA wsaData;
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
{
printf("Error: Wsastartup\n");
exit(1);
}
int iRes;
addrinfo *result, *ptr, addr;
SecureZeroMemory(&addr, sizeof(addr));
addr.ai_family = AF_INET;
addr.ai_protocol = IPPROTO_TCP;
addr.ai_socktype = SOCK_STREAM;
iRes = getaddrinfo(USR_ADDR, USR_PORT, &addr, &result);
if ( iRes != 0 )
{
printf("Error: getaddrinfo");
WSACleanup();
exit(2);
}
SOCKET ConnSocket;
ptr = result;
ConnSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
if (ConnSocket == INVALID_SOCKET)
{
printf("Error: socket: %ld \n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
exit(3);
}
if (connect(ConnSocket, ptr->ai_addr, (int)ptr->ai_addrlen) )
{
closesocket(ConnSocket);
ConnSocket = INVALID_SOCKET;
}
if (ConnSocket == INVALID_SOCKET)
{
printf("Invalid Socket\n");
exit(4);
}
const char *send_buf = HEADER_TO_SEND;
char recv_buf[BUFF_LEN];
if ((iRes = send(ConnSocket, send_buf, strlen(send_buf) - 1, 0)) == SOCKET_ERROR)
{
printf("Error: send\n");
closesocket(ConnSocket);
WSACleanup();
exit(5);
}
int i;
for (i = 0; i < iRes; i++)
printf("%c", send_buf[i]);
printf("Bytes sent: %d\n", iRes);
//if (shutdown(ConnSocket, SD_SEND) == SOCKET_ERROR)
//{
// printf("Error: shutdown: %d\n", WSAGetLastError());
// closesocket(ConnSocket);
// WSACleanup();
// exit(6);
//}
//do {
iRes = recv(ConnSocket, recv_buf, sizeof(recv_buf)-1, 0);
if (iRes > 0)
{
printf("Bytes received: %d\n", iRes);
recv_buf[iRes] = '\0';
for (i = 0; i < iRes; i++)
printf("%c", recv_buf[i]);
}
else if (iRes == 0)
printf("Connection closed by the server.\n");
else printf("Error: %d\n", WSAGetLastError());
//} while (iRes > 0);
getchar();
getchar();
closesocket(ConnSocket);
WSACleanup();
return 0;
}