js/core/net/udp.js
function receive(intf, srcIP, destIP, u8, headerOffset) {
  const srcPort = udpHeader.getSrcPort(u8, headerOffset);
  const destPort = udpHeader.getDestPort(u8, headerOffset);
  const dataLength = udpHeader.getDataLength(u8, headerOffset) - udpHeader.headerLength;
  const dataOffset = headerOffset + udpHeader.headerLength;
  debug('recv UDP over IP4', srcPort, destPort, dataLength);

  const socket = UDPSocket.lookupReceive(destPort);
  if (!socket) {
    return;
  }

  const u8data = u8.subarray(dataOffset);
  if (socket.onmessage) setImmediate(() => socket.onmessage(srcIP, srcPort, u8data));
}
function receive(intf, srcIP, destIP, u8, headerOffset) {
  const srcPort = udpHeader.getSrcPort(u8, headerOffset);
  const destPort = udpHeader.getDestPort(u8, headerOffset);
  const dataLength = udpHeader.getDataLength(u8, headerOffset) - udpHeader.headerLength;
  const dataOffset = headerOffset + udpHeader.headerLength;
  debug('recv UDP over IP4', srcPort, destPort, dataLength);

  const socket = UDPSocket.lookupReceive(destPort);
  if (!socket) {
    return;
  }

  const u8data = u8.subarray(dataOffset);
  if (socket.onmessage) setImmediate(() => socket.onmessage(srcIP, srcPort, u8data));
}
const portUtils = require('./port-utils'); const IP4Address = require('./ip4-address'); const interfaces = require('./interfaces'); const netError = require('./net-error');