Binding 2 UDP sockets on same port, connected to different destinations, 1 receives

Posted on 16th Feb 2014 07:03 pm by admin

Hello,
My application wants to send/recv data to 2 different UDP ports on a remote computer, using the same source port.
So I bind to the same local port which works, and connect to the remote IP : port which works as well, but then randomly only one of the two sockets will receive data from the stack, even though packets are arriving on the network for both.

In this code, the local UDP port is always 13398; the first time this code is called, the destination is 192.168.13.45:6970 and the second time it's 192.168.13.45:6972.
What would cause only one of the sockets to receive data afterwards? Also it's randomly the first or the second one that receive data, but once both sockets are binded and connected, only that random one will receive data.

Thanks!

SOCKET serverSock = ::socket(AF_INET, SOCK_DGRAM,IPPROTO_UDP);
int i=1;
if ( setsockopt(serverSock, SOL_SOCKET, SO_REUSEADDR, (char *)&i, sizeof(i)) != 0 ) {
logger.warn(_T("Could not set SO_REUSEADDR: %s"), GetWSATextError(WSAGetLastError()));
}

SOCKADDR_IN saServer, dest;
memset(&saServer,0,sizeof(saServer));
saServer.sin_family = AF_INET;
saServer.sin_addr.s_addr = INADDR_ANY; // Since this is a server, any address will do
saServer.sin_port = htons(m_manager->GetLocalUDPPort()); // Convert int to a value for the port field
int ret = bind(serverSock, (struct sockaddr *) &saServer, sizeof(saServer));
if (ret != 0) {
logger.warn(_T("Could not bind to udp port 1: %d, %s"), m_manager->GetLocalUDPPort(), GetWSATextError(WSAGetLastError()));
return false;
}

memset(&dest,0,sizeof(dest));
dest.sin_family=AF_INET;
dest.sin_addr.s_addr=m_deviceIP;
dest.sin_port = htons(m_devicePort1);
ret = connect(serverSock, (sockaddr *) &dest, sizeof(dest));
if (ret != 0) {
logger.warn(_T("Failed to connect to udp 1: %s:%d, %s"), inet_ntoa(dest.sin_addr), m_devicePort1, GetWSATextError(WSAGetLastError()));
return false;
}

Your Answer:

Login to answer

Other forums

isset undefined variable
Hi all,

Hope someone can point out the obvious. I've a log in script, if you dont enter a use

problem with script manager
Hi iam using Net.2005.I have created ajax enabledwebsite.i have master page in which i have script m

If a form submits back to same page do you need to use $get
IM trying to pass page number and year that was selected back to the same page.

i have this c

Socket Server Response Headers
Earlier I had a post about my Socket Server, I wasn't able to get it to connect, now I can

I

Displaying image from database
Hi,

I've got a site where that's got a database behind it. Currently it has loads of items in

Retrieving innerHTML with cURL?
Hey all (sorry I know I'm a leecher, but I soon won't be. This is my first PHP project, but not my l

tell csv import script to ignore blank rows?
Hi i have the below script but i get an error if a row is blank ie a return in the csv file at the e

Get keys and values from an array
Hellow,

I have an array $Data with keys and values. With a foreach I can display all the valu

Bit manipulation program with binary operations
My homework is to create a program to scan in and add binary numbers and print them like so

Greek characters in php
Hi,

I'm making a script and I m using for first time greek characters.
I started to write