/* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* LibMemcached
*
* Copyright (C) 2011 Data Differential, http://datadifferential.com/
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* * The names of its contributors may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <libmemcached/common.h>
/*
* The udp request id consists of two seperate sections
* 1) The thread id
* 2) The message number
* The thread id should only be set when the memcached_st struct is created
* and should not be changed.
*
* The message num is incremented for each new message we send, this function
* extracts the message number from message_id, increments it and then
* writes the new value back into the header
*/
void increment_udp_message_id(memcached_instance_st* ptr)
{
struct udp_datagram_header_st *header= (struct udp_datagram_header_st *)ptr->write_buffer;
uint16_t cur_req= get_udp_datagram_request_id(header);
int msg_num= get_msg_num_from_request_id(cur_req);
int thread_id= get_thread_id_from_request_id(cur_req);
if (((++msg_num) & UDP_REQUEST_ID_THREAD_MASK) != 0)
msg_num= 0;
header->request_id= htons((uint16_t) (thread_id | msg_num));
}
bool memcached_io_init_udp_header(memcached_instance_st* ptr, const uint16_t thread_id)
{
if (thread_id > UDP_REQUEST_ID_MAX_THREAD_ID)
{
return MEMCACHED_FAILURE;
}
struct udp_datagram_header_st *header= (struct udp_datagram_header_st *)ptr->write_buffer;
header->request_id= htons(uint16_t((generate_udp_request_thread_id(thread_id))));
header->num_datagrams= htons(1);
header->sequence_number= htons(0);
return MEMCACHED_SUCCESS;
}