+#ifndef LIBMEMCACHED_MEMCACHED_IO_H
+#define LIBMEMCACHED_MEMCACHED_IO_H
+
+#if defined(BUILDING_LIBMEMCACHED)
+
+#include "libmemcached/memcached.h"
+
+#define MAX_UDP_DATAGRAM_LENGTH 1400
+#define UDP_DATAGRAM_HEADER_LENGTH 8
+#define UDP_REQUEST_ID_MSG_SIG_DIGITS 10
+#define UDP_REQUEST_ID_THREAD_MASK 0xFFFF << UDP_REQUEST_ID_MSG_SIG_DIGITS
+#define get_udp_datagram_request_id(A) ntohs((A)->request_id)
+#define get_udp_datagram_seq_num(A) ntohs((A)->sequence_number)
+#define get_udp_datagram_num_datagrams(A) ntohs((A)->num_datagrams)
+#define get_msg_num_from_request_id(A) ( (A) & (~(UDP_REQUEST_ID_THREAD_MASK)) )
+#define get_thread_id_from_request_id(A) ( (A) & (UDP_REQUEST_ID_THREAD_MASK) ) >> UDP_REQUEST_ID_MSG_SIG_DIGITS
+#define generate_udp_request_thread_id(A) (A) << UDP_REQUEST_ID_MSG_SIG_DIGITS
+#define UDP_REQUEST_ID_MAX_THREAD_ID get_thread_id_from_request_id(0xFFFF)
+
+struct udp_datagram_header_st {
+ uint16_t request_id;
+ uint16_t sequence_number;
+ uint16_t num_datagrams;
+ uint16_t reserved;
+};