+/* 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_server_write_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_server_write_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;
+}