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

error checking breaking my code
Hi there, OK first of all, big apologies for what I assume is really fundamental errors in the struc

Switch letters in message (basic cryptology)...
I am trying to switch letters around in a message for an application on my site (see here). The prob

Remove values in array2 from array1
I have two arrays.

Array 1 is where the array key holds various different numbers. For exampl

How to create a static html menu from a database
Hi,

I have built a small cms which allows me to create simple html pages and then upload them

LSB (PHP 5.3) problem with static value!
hello,

i'm having a problem. static::$text variable gets lost at some point. can someone plea

Nested (echoed) php running wrong script
Got a problem with a php website I'm creating.

In a nutshell, the first page is entirely html

PHP & MS Access - Line Break
Hey Guys!

I'm pulling records from an MS Access database and listing them using PHP and I'm r

fopen() security
As i understood the usage of fopen() for it to function correctly the Dir you write to has to be rw

php calculate
this code echoes correctly the sum but the inserted result is 0??
Code: <?php
$TotalNum

problems with php variables in mysql query
i can't seem to get the following query to work.

select $q1c from $vote_rate where id = $re