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

Comment Mod System Effects all rows...
Sorry if its confusing but here is whats going on: I have a table in a database called comments and

Unable to display contents in Second Drop Down Box
Hi All,

What I am trying to do is 2 dependent drop down boxes and when user selects su

Help pulling in 'id' with "read more" link
I'm trying to create snippets of my articles in the cms I'm creating, and then have them redirect to

Rand() help needed
Hi all,

Can someone explain and give me a quick example of how I would go about this?

Confusing Functions
So, I've been reading up on Functions and I like them! However, I need some help using variables in

DB2 for z/OS, LUW, iSeries
Hello, In this forum a lot of threads related to other members of the DB2 family than DB2 for z/OS

Need help: how to catch acess of undefined class properties
Hello. I am learning OO with PHP and have hit a problem.
Some code runs as perfectly valid code,

timezone change with date()
so i put all my times for posts in my made from scratch forum(not phpbb3 or sm)
in my mysql db u

Changing color in GD via variable?
Hey guys, I'm new here. x)

I'm very much a noob when it comes to PHP, but I'm trying to learn

How to add functionality to a simple php calender?
Hello everyone,

I have just finished creating a simple php calander. Can someone point