/** Send a message to the address specified in dest */
void sendUdpMessage(Message msg) throws Exception {
IpAddress dest;
Message copy;
Event evt;
dest = (IpAddress) msg.getDest(); // guaranteed not to be null
setSourceAddress(msg);
if (Trace.debug) {
Trace.debug(
"UDP.sendUdpMessage()",
"sending message to "
+ msg.getDest()
+ " (src="
+ msg.getSrc()
+ "), headers are "
+ msg.getHeaders());
// Don't send if destination is local address. Instead, switch dst and src and put in
// up_queue.
// If multicast message, loopback a copy directly to us (but still multicast). Once we receive
// this,
// we will discard our own multicast message
}
if (loopback && (dest.equals(local_addr) || dest.isMulticastAddress())) {
copy = msg.copy();
copy.removeHeader(name);
copy.setSrc(local_addr);
copy.setDest(dest);
evt = new Event(Event.MSG, copy);
/* Because Protocol.up() is never called by this bottommost layer, we call up() directly in the observer.
This allows e.g. PerfObserver to get the time of reception of a message */
if (observer != null) {
observer.up(evt, up_queue.size());
}
if (Trace.debug) {
Trace.info("UDP.sendUdpMessage()", "looped back local message " + copy);
}
passUp(evt);
if (!dest.isMulticastAddress()) {
return;
}
}
if (use_outgoing_packet_handler) {
outgoing_queue.add(msg);
return;
}
send(msg);
}
/**
* If the sender is null, set our own address. We cannot just go ahead and set the address anyway,
* as we might be sending a message on behalf of someone else ! E.g. in case of retransmission,
* when the original sender has crashed, or in a FLUSH protocol when we have to return all
* unstable messages with the FLUSH_OK response.
*/
void setSourceAddress(Message msg) {
if (msg.getSrc() == null) {
msg.setSrc(local_addr);
}
}