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

update sql when refresh - php
hi
I have made a table (attachement)

the users can update the sql database using + or x bu

user data not transferring to new page
I'm a PHP learner. After an index.php page, the user goes to a login.php page. Both pages seem to

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

Save username into DB
OkaY so I got my blog to actually save the posts and whatever, all I need now is for it to keep the

Using the $_GET variable to view certain records
Hello,

First let me explain my problem, I have 2 pages the first page pull a list of Guide ti

getting rid of quotes in strings
sick of trying to deal with them in multiple ways (entering in and taking from database, echoing, ec

Buggy registration system
Hey, I just started scripting in PHP, and I ran into a few problems.
Code: <?php
includ

How to store checkbox array in a session, and then be able to add to it?
I'm trying to store an array of checkbox values into a session array, sort of like a shopping cart,

This must be easy , pulling the last record of the day, every day, from a txt
I have a txt file logging weather data every minutes (so 1 record per minute). I want to extract the

images aren't rendering
I'm trying to call a JPG file from within PHP (in an effort to hide the actual JPG folder). The imag