SetSocketSize seems to be circumvented

[clevertoys]

Code such as this silently fails to change the recv buf size, and incoming packets never arrive

// start UDP
Ethernet.setSocketSize(1620 * 3);
Udp.begin(T_PORT);

I looked at the code and found this:

void EthernetClass::setSocketSize(size_t _socket_size)
{
if(socket_size != 0) return;
socket_size = _socket_size;
}

This effectively disallows setting of the size unless the size is zero. No idea who sets the initial value, but it isn't zero when I call setSocketSize, and so my call has no effect. I doubt that is what was intended, but please let me know if I am missing something here. I changed the code to this:

void EthernetClass::setSocketSize(size_t _socket_size)
{
//if(socket_size != 0) return;
socket_size = _socket_size;
}

And now all is working fine for me. I think what you want here is something like (NOTE: I do not know where the actual max packet size is to be found. I just used a made up symbol MAX_MTU here...)

void EthernetClass::setSocketSize(size_t _socket_size)
{
if(_socket_size > MAX_MTU) _socket_size = MAX_MTU;
socket_size = _socket_size;
}

I found this:

#define UDP_TX_PACKET_MAX_SIZE 2048

but it is never used. In any case, I think programs should be allowed to set the recv buf size up to the actual limit of the physical transport, whatever that might be...