This is a demo of receiving udp packets with an avr-netio board, Arduino and avr-netino.

avrnetio_udpreceive.ino

// 
// Environment: 
//   * Pollin AVR NETIO board, 
//   * Arduino 1.0.3, 
//   * avr-netino (https://code.google.com/p/avr-netino/)
//
// This is a demo of receiving udp packets
// 
// 2012-12-22 <Thomas.Mohaupt@gmail.com> http://creativecommons.org/licenses/by-sa/3.0/
// Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
// 
// Example to send udp packets to board: https://gist.github.com/4359006
// 
// Note: you need to specify the gateway
 
#include <EtherCard.h>
 
static unsigned int NETIO_CSPIN_ENC28J60 = 28;
 
byte macMy[]         = {0x00, 0x22, 0xF9, 0x01, 0x30, 0xDA };
byte ipMy[]          = {10, 0, 0, 52};
byte ipGateway[]     = {10, 0, 0, 254};
word portMy          = 7777;
 
byte Ethernet::buffer[220];
 
void setup() {
  ether.begin(sizeof Ethernet::buffer, macMy, NETIO_CSPIN_ENC28J60);
  ether.hisport = portMy;  
  ether.staticSetup(ipMy, ipGateway);
 
  while (ether.clientWaitingGw())
    ether.packetLoop(ether.packetReceive());
    
  Serial.begin(9600);
  Serial.println("finish setup");  
}
 
void loop() {
  word len = ether.packetReceive();
  word pos = ether.packetLoop(len);
  if (pos) {
    Serial.println((const char *) &ether.buffer[pos]);
  }
}