Windows Socket unable to bind on VPN IP address - c++

Question

I am trying to bind to particular IP which is over a VPN network and I am able to ping it, connect it and also able to telnet on particular port but my windows MFC program gives error code 10049 and I am not able to go further any help in debugging this problem will be appreciated, I am running this on Visual Studio 2012 Win 7 and remote client is running on Linux variant.
This is part of code where I am getting error basically IP address is configurable but I am hardcoding it to debug.
CStarDoc *p_doc = (CStarDoc*) lpparam;
BOOL fFlag = TRUE;
const int MAX_MSGLEN = max(sizeof(DISP_INFO_T ), sizeof(REASON_STRING_T ));
char buffer[MAX_MSGLEN];
DISP_INFO_T *p_disp_info_buffer = (DISP_INFO_T *) buffer;
DISP_INFO_T disp_info_combined; //receiving combined butter
DISP_INFO_T_1 *p_disp_info_buffer1; //receiving buffer pointer for DispInfo1
DISP_INFO_T_2 *p_disp_info_buffer2; //receiving buffer pointer for DispInfo2
int msgReceived = 0; // Initially, is 0.
// For the same msgNumber, when the program receives the first portion of buffer, set to 1,
// When the program receives both portions, set it to 0.
// When the program misses any portion for the same msgNumber, set to 0 also.
int currentMsgNum1 = 0;
int currentMsgNum2 = 0;
int err;
CString msg;
SOCKADDR_IN saUDPPortIn;
SOCKADDR_IN From;
struct addrinfo *result = NULL;
struct addrinfo *ptr = NULL;
struct addrinfo hints;
::memset( &hints,0, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
//hints.ai_socktype = SOCK_DGRAM;
//hints.ai_protocol = IPPROTO_UDP;
char asideip[] = "192.168.1.129";
BOOL OtherSideIsStandby = FALSE;
static BOOL DoFirstMsg = TRUE;
// p_disp_info_combined = & disp_info_combined;
p_doc->ThreadRunning = TRUE;
p_doc->udpsocket = socket(AF_INET, SOCK_DGRAM, 0);
if (INVALID_SOCKET == p_doc->udpsocket)
{
CString msg = "Invalid socket: "+ WSAGetLastError();
AfxMessageBox(msg);
return(-1);
}
long ip = 0;
int sockbufsize = 0;
int timeout = 2000;
// This is the IP that matches the IP of the QNX machines in all but the last octet.
// Note: it is in host byte format.
int errcode = getaddrinfo(asideip,NULL,&hints,&result);
for(ptr = result;ptr != NULL ;ptr=ptr->ai_next)
{
switch (ptr->ai_family)
{
default: break;
case AF_INET :
ip = p_doc->MyIP;
saUDPPortIn.sin_family = AF_INET;
saUDPPortIn.sin_addr.s_addr = (((SOCKADDR_IN*) ptr->ai_addr)->sin_addr).s_addr;
saUDPPortIn.sin_port = htons(p_doc->port_addr );
int length = sizeof(buffer) *2;
//err = setsockopt(p_doc->udpsocket,SOL_SOCKET, SO_REUSEADDR, (char *)&fFlag, sizeof(fFlag));
//err = setsockopt(p_doc->udpsocket,SOL_SOCKET, SO_BROADCAST, (char *)&fFlag, sizeof(fFlag));
err = setsockopt(p_doc->udpsocket, SOL_SOCKET, SO_RCVBUF, (char *)&length, sizeof(length));
// Keep from hanging forever.
err = setsockopt(p_doc->udpsocket, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
err = bind(p_doc->udpsocket, (SOCKADDR FAR *)&saUDPPortIn, sizeof(SOCKADDR_IN));
if (err == SOCKET_ERROR)
{
int errcode = WSAGetLastError();
closesocket(p_doc->udpsocket);
/* msg.Format("Network Connectivity failed, Please Check Network. ");
AfxMessageBox(msg);
closesocket(p_doc->udpsocket);
p_doc->udpsocket = -1; // task is trying to attach to the port.
return(1);*/
}
}
}
Thanks

Answer 1

You can not bind to remote address and as your error shows, it is such case. You use bind system call with local IP and Port.
Here is what MSDN says about your error:
WSAEADDRNOTAVAIL 10049
Cannot assign requested address. The requested address is not valid in
its context. This normally results from an attempt to bind to an
address that is not valid for the local computer. This can also result
from connect, sendto, WSAConnect, WSAJoinLeaf, or WSASendTo when the
remote address or port is not valid for a remote computer (for
example, address or port 0).