UDP source port

extend
#1

I need to specify the source port of a UDP message (this is not the same as destination port, but it is the port it a message is sent from). I need to communicate with some professional hardware, it will reply using whatever is the source port of a message.

I had previously worked around this with Poco:

I am wondering if there is another workaround as Poco is not longer part of OF.

As I read (http://serverfault.com/questions/341263/how-are-udp-source-ports-selected) there is difference in the way windows mac and linux will generate source ports for UDP messages). It would be great to rectify this across platforms, I am approaching this problem for something that needs to run on OSX and Windows.

Fred

#2

poco is still present as an addon so any old code relying on it will keep working just by including that addon in your project.

and yes i guess it should be relatively straightforward to add a method to get the source port to the ofxNetwork classes

#3

Cheers, I just found it, will give it a go with ofxPoco.

#4

hi @fresla,

I’ve been in the same situation as you in the past and have done this by binding the to port that I want to remote hardware to respond to, without ofxPoco.

Here I send to port 5555 of the device, the device will reply to my IP address on port 5556.

// send
std::string ip = "192.168.130.255";
m_udpSend.Create();
m_udpSend.Bind(5556);
m_udpSend.SetEnableBroadcast(true);
m_udpSend.Connect(ip.c_str(), 5555);

char buf[2];
buf[0] = 'P';
buf[1] = 'B';

if (m_udpSend.Send(buf, 2))
{
    printf("Sent %s to IP: %s\n", buf, ip.c_str());
}
#5

oh yeah i totally forgot about that, using Bind you can select which port you want the socket to listen at

#6

Ok, I’ll do some tests and see how I go. looks like a great and super easy solution.

Fred