Unable to receive data from multiple UDP devices - c++

Question

I am using the EIPScanner library to talk to 2 TURCK I/O modules via EthernetIP. The library works fine with one module, but the moment I instantiate the driver for the second one, the first one times out.
I tried to modify the library by passing a port number to listen on, but it didn't seem to make a difference:
In ConnectionManager.cpp
IOConnection::WPtr
ConnectionManager::forwardOpen(const SessionInfoIf::SPtr& si, ConnectionParameters connectionParameters, int port, bool isLarge) {
....
....
....
if (o2tSockAddrInfo != additionalItems.end())
{
Buffer sockAddrBuffer(o2tSockAddrInfo->getData());
sockets::EndPoint endPoint("",0);
sockAddrBuffer >> endPoint;
endPoint.setPort(port)
if (endPoint.getHost() == "0.0.0.0") {
ioConnection->_socket = std::make_unique<UDPSocket>(
si->getRemoteEndPoint().getHost(), endPoint.getPort());
} else {
ioConnection->_socket = std::make_unique<UDPSocket>(endPoint);
}
}
I tried adding a timeout to the recvfrom() function, but that also didn't make a difference.
In UDPSocket.cpp
UDPSocket::UDPSocket(EndPoint endPoint)
: BaseSocket(EndPoint(std::move(endPoint))) {
_sockedFd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (_sockedFd < 0) {
throw std::system_error(BaseSocket::getLastError(), BaseSocket::getErrorCategory());
}
/*struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 1;
setsockopt(_sockedFd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));*/
Logger(LogLevel::DEBUG) << "Opened UDP socket fd=" << _sockedFd;
}
Output:
[DEBUG] Opened TCP socket fd=7
[DEBUG] Connecting to 192.168.1.130:44818
[INFO] Registered session 103
[DEBUG] Opened TCP socket fd=8
[DEBUG] Connecting to 192.168.1.131:44818
[INFO] Registered session 103
2021-06-18 13:03:02,996 Process-1
2021-06-18 13:03:02,997 Process-1 [INFO] Send request: service=0x54 epath=[classId=6 objectId=1]
[INFO] Open IO connection O2T_ID=1781321728 T2O_ID=915406849 SerialNumber 1
[DEBUG] Opened UDP socket fd=15
[INFO] Open UDP socket to send data to 192.168.1.130:2223
[DEBUG] Opened UDP socket fd=16
[INFO] Will look for id: 915406849 from endPoint: 192.168.1.130:2222
[DEBUG] Received data from connection T2O_ID=915406849(host: 192.168.1.130:2223)
[DEBUG] Received: seq=2 data=[0][0][0][0]
[DEBUG] Received data from connection T2O_ID=915406849(host: 192.168.1.130:2223)
[DEBUG] Received: seq=3 data=[0][0][0][0]
2021-06-18 13:03:03,112 Process-2
2021-06-18 13:03:03,113 Process-2
[INFO] Send request: service=0x54 epath=[classId=6 objectId=1]
[INFO] Open IO connection O2T_ID=1782571776 T2O_ID=1911881729 SerialNumber 1
[DEBUG] Received data from connection T2O_ID=1911881729(host: 192.168.1.130:2223)
[DEBUG] Received: seq=1 data=[0][0][4][0]
[DEBUG] Opened UDP socket fd=20
[INFO] Open UDP socket to send data to 192.168.1.131:2224
[DEBUG] Opened UDP socket fd=21
[INFO] Will look for id: 1911881729 from endPoint: 192.168.1.131:2222
[DEBUG] Received data from connection T2O_ID=915406849(host: 192.168.1.131:2224)
[DEBUG] Received: seq=4 data=[0][0][0][0]
[DEBUG] Received data from connection T2O_ID=1911881729(host: 192.168.1.131:2224)
[DEBUG] Received: seq=2 data=[0][0][4][0]
As you can see once the device on 192.168.1.131 starts streaming, the 1.130 device stops. And eventually it times out and shuts down.