git.m6w6.name Git - awesomized/libmemcached/blob - src/libmemcached/udp.cc

   1 /*
   2     +--------------------------------------------------------------------+
   3     | libmemcached - C/C++ Client Library for memcached                  |
   4     +--------------------------------------------------------------------+
   5     | Redistribution and use in source and binary forms, with or without |
   6     | modification, are permitted under the terms of the BSD license.    |
   7     | You should have received a copy of the license in a bundled file   |
   8     | named LICENSE; in case you did not receive a copy you can review   |
   9     | the terms online at: https://opensource.org/licenses/BSD-3-Clause  |
  10     +--------------------------------------------------------------------+
  11     | Copyright (c) 2006-2014 Brian Aker   https://datadifferential.com/ |
  12     | Copyright (c) 2020 Michael Wallner   <mike@php.net>                |
  13     +--------------------------------------------------------------------+
  14 */
  15
  16 #include "libmemcached/common.h"
  17
  18 /*
  19  * The udp request id consists of two seperate sections
  20  *   1) The thread id
  21  *   2) The message number
  22  * The thread id should only be set when the memcached_st struct is created
  23  * and should not be changed.
  24  *
  25  * The message num is incremented for each new message we send, this function
  26  * extracts the message number from message_id, increments it and then
  27  * writes the new value back into the header
  28  */
  29 void increment_udp_message_id(memcached_instance_st *ptr) {
  30   struct udp_datagram_header_st *header = (struct udp_datagram_header_st *) ptr->write_buffer;
  31   uint16_t cur_req = get_udp_datagram_request_id(header);
  32   int msg_num = get_msg_num_from_request_id(cur_req);
  33   int thread_id = get_thread_id_from_request_id(cur_req);
  34
  35   if (((++msg_num) & UDP_REQUEST_ID_THREAD_MASK))
  36     msg_num = 0;
  37
  38   header->request_id = htons((uint16_t)(thread_id | msg_num));
  39 }
  40
  41 bool memcached_io_init_udp_header(memcached_instance_st *ptr, const uint16_t thread_id) {
  42   if (thread_id > UDP_REQUEST_ID_MAX_THREAD_ID) {
  43     return MEMCACHED_FAILURE;
  44   }
  45
  46   struct udp_datagram_header_st *header = (struct udp_datagram_header_st *) ptr->write_buffer;
  47   header->request_id = htons(uint16_t((generate_udp_request_thread_id(thread_id))));
  48   header->num_datagrams = htons(1);
  49   header->sequence_number = htons(0);
  50
  51   return MEMCACHED_SUCCESS;
  52 }