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

Pro-rata Billing in Periodic Billing for Rental
Hi guys,

We have a situation, where a rental contract starts at the mid of the month say

CE 7.1 and External GIS integration
Hi All,

We want to develop an application on CE 7.1 which uses GIS features from an exter

Help? Need help on project with templates involving mysql and php.
I'm having a hard time explaining what I want but basically here is what I have in place:

-Da

Best PHP Documentation generator
Hello guys!

I would like to hear from you what is the best PHP documentation generator. Perso

Changing files over
Just thought I'd start with the new forums looking really nice .

Ok basically I've made this

IF STATEMENT HELP
Hi
i have created a calendar from a table:

Code: Calendar: October 2009
<table w

ALV List Display to point to another report on Double Click
Hi,

I want my ALV List Display to point to another report on Double Click on its line ite

Text Not Displaying Correctly With PHP:GD
I recently moved servers and since then I have noticed that one line of text is showing weirdly.

Please help with SMTP Authenticated PHP Email Form
Hello, I'm creating a PHP email form, and for this particular server, I have to use SMTP Authenticat

Problems with strings containing
Hey all,

I have encountered something strange in a script. I am trying to write an XML heade