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

Is STL important?
I'm just starting programming and I've made it until the Standart Template Library. But the chapter

Cannot Connect to Database
I am writing an application to do annual reviews. I cannot get my script to work. Whenever it runs I

Escape Latin Characters
I need to escape latin characters in an xml doc. Example: "é" is escaped to "é". I thoug

Map.php
I am a complete beginner to PHP and am looking for some help with a program I am messing around with

parse error
Parse error: syntax error, unexpected '[', expecting ')' in /Users/admin/Sites/phptest/array.php on

login to other site by sending post variables
hey,

here is my problem: my school gave me a mail account for school-stuff use. they mail us

News script
Hi ...

I am not sure if this is the rite place to post this but if its not sorry

i am

Access website from only 1 computer...?
One of my customers wants his website to only be accessed by people in which they bought the website

need help with mail()
hi i want to send an email with attaching pdf file using php. i have the following script but the pr

Edit MySQL Row Using PHP and HTML Form
Hello,

Here's what I'm trying to do. Build a page where a user enters a MySQL row number in.