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

New to PHP and just trying to understand a little code.
I hope I'm not annoying anyone or breaking the rules but I was wondering about this bit of code righ

weeks in a year
hi,

i found this snippet on php.net
QuoteFor the week number for weeks starting on Sunday:

get multiple rows
Hi I want to get multiple rows from a db

I am using this for the db query
Code: public

Deleting a record php
Attempting to setup delete a record page. The below code I put together doesn't seem to work.

Displaying Multidimensional Arrays...about to put my head in a vice, PLEASE HELP
I am fairly new to PHP and MySQL and I have a problem which I have been trying to resolve for days.

Upload, SSL and more php help
I recently just installed a ssl cert and do i use https for the whole site or just for the checkout.

using file_get_contents??
okay how would i create a script using file_get_contents() in php have it grab search pages 1-20 and

Odd or Even
Inside of a while loop I need to echo several rows of info...easy enough.

In the loop (for th

mysql query with single quotes in a variable
$sitedetails = "INSERT INTO vars (address, sitename, description, ownername, theme) VALUES ('$u

Question about ShowWindow()
Hello....

I'm struggling with sumpin, and I hope y'all can help.

I've got a CFormView