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

need help to creat database
Hello Team, please guys i am stuck from three days with paypal issue for IPN but no luck yet now i w

EU VAT Package 2010
Does any one know whether SAP will be developing new reporting functionality due the new VAT rules t

News script
Hi ...

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

i am

Specific name typed, specific image shown on html page
Hello,

Fairly new to PHP and was curious if someone might know how to solve a fairly simple r

Pagination
Hi All,

I think I'm finally getting somewhere with pagination!

I can now submit a quer

Procedural to OOP
ohn Kleijn said that to avoid writing "crappy code", we should learn OOP and common OO pri

Simple Question
I know this is a simple question, that if I knew what it was technically called i could probably loo

IIS7 and getimagesize() problem
I have just discovered after hrs of trying to fix a problem where it's coming from. It's to do with

Page doesn't expand for content
Hi. I've been testing a query I made. It's here http://lapr1.6te.net/inquerito.php
The page doesn

SQl num_rows problem
when i try to count rows from an SQL select i get an warning

Code: [Select]$countviews = mysq