Mercurial > hg > freeDiameter
view extensions/rt_randomize/rt_randomize.c @ 1278:2a7b32176d2e
Add extension to randomly choose one of the highest-scored hosts,
by increasing their score by one.
author | Thomas Klausner <tk@giga.or.at> |
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date | Wed, 06 Aug 2014 15:21:16 +0200 |
parents | |
children | 38e4a7c318ac |
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/********************************************************************************************************* * Software License Agreement (BSD License) * * Author: Thomas Klausner <tk@giga.or.at> * * * * Copyright (c) 2014 Thomas Klausner * * All rights reserved. * * * * Written under contract by nfotex IT GmbH, http://nfotex.com/ * * * * Redistribution and use of this software 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. * * * * 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 <freeDiameter/extension.h> /* * Load balancing extension. If there are multiple highest-rated hosts with the same score, * randomly increase the score of one of them. */ #include <stdlib.h> static int seed; static int rt_randomizing(void * cbdata, struct msg ** pmsg, struct fd_list * candidates) { struct fd_list *lic; struct msg * msg = *pmsg; int max_score = -1; int max_score_count = 0; TRACE_ENTRY("%p %p %p", cbdata, msg, candidates); CHECK_PARAMS(msg && candidates); /* Check if it is worth processing the message */ if (FD_IS_LIST_EMPTY(candidates)) return 0; /* find out maximal score and how many candidates have it */ for (lic = candidates->next; lic != candidates; lic = lic->next) { struct rtd_candidate * cand = (struct rtd_candidate *) lic; if (max_score < cand->score) { max_score = cand->score; max_score_count = 1; } else if (cand->score == max_score) { max_score_count++; } } /* if there is more than one with positive score, randomly increase one of their scores by one */ if (max_score >= 0 && max_score_count > 1) { int lucky_candidate = rand_r(&seed) % max_score_count; int i = 0; for (lic = candidates->next; lic != candidates; lic = lic->next) { struct rtd_candidate * cand = (struct rtd_candidate *) lic; if (cand->score == max_score) { if (i == lucky_candidate) { cand->score++; break; } i++; } } } return 0; } /* handler */ static struct fd_rt_out_hdl * rt_randomizing_hdl = NULL; /* entry point */ static int rt_randomize_entry(char * conffile) { /* Register the callback */ CHECK_FCT(fd_rt_out_register(rt_randomizing, NULL, 4, &rt_randomizing_hdl)); seed = (int)time(NULL); TRACE_DEBUG(INFO, "Extension 'Randomizing' initialized"); return 0; } /* Unload */ void fd_ext_fini(void) { /* Unregister the callbacks */ CHECK_FCT_DO(fd_rt_out_unregister(rt_randomizing_hdl, NULL), /* continue */); return ; } EXTENSION_ENTRY("rt_randomize", rt_randomize_entry);