Initial commit
Change-Id: I6a4444e3c193dae437cd7929f4c39aba7b749efa
diff --git a/extensions/rt_load_balance/rt_load_balance.c b/extensions/rt_load_balance/rt_load_balance.c
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+/*********************************************************************************************************
+* Software License Agreement (BSD License) *
+* Author: Thomas Klausner <tk@giga.or.at> *
+* *
+* Copyright (c) 2013, 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. Send request to least-loaded node.
+ */
+
+/* The callback for load balancing the requests across the peers */
+static int rt_load_balancing(void * cbdata, struct msg ** pmsg, struct fd_list * candidates)
+{
+ struct fd_list *lic;
+ struct msg * msg = *pmsg;
+
+ 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;
+
+ /* load balancing */
+ for (lic = candidates->next; lic != candidates; lic = lic->next) {
+ struct rtd_candidate * cand = (struct rtd_candidate *) lic;
+ struct peer_hdr *peer;
+ long to_receive, to_send, load;
+ int score;
+ CHECK_FCT(fd_peer_getbyid(cand->diamid, cand->diamidlen, 0, &peer));
+ CHECK_FCT(fd_peer_get_load_pending(peer, &to_receive, &to_send));
+ load = to_receive + to_send;
+ /* other routing mechanisms need to add to the
+ * appropriate entries so their base value is high
+ * enough that they are considered */
+
+ /* logarithmic scaling */
+ int load_log = 0;
+ while (load > 0) {
+ load_log++;
+ load /= 2;
+ }
+ score = cand->score;
+ cand->score -= load_log;
+ TRACE_DEBUG(FULL, "evaluated peer `%.*s', score was %d, now %d", (int)cand->diamidlen, cand->diamid, score, cand->score);
+ }
+
+ return 0;
+}
+
+/* handler */
+static struct fd_rt_out_hdl * rt_load_balancing_hdl = NULL;
+
+/* entry point */
+static int rt_load_balance_entry(char * conffile)
+{
+ /* Register the callback */
+ CHECK_FCT(fd_rt_out_register(rt_load_balancing, NULL, 10, &rt_load_balancing_hdl));
+
+ TRACE_DEBUG(INFO, "Extension 'Load Balancing' initialized");
+ return 0;
+}
+
+/* Unload */
+void fd_ext_fini(void)
+{
+ /* Unregister the callbacks */
+ CHECK_FCT_DO(fd_rt_out_unregister(rt_load_balancing_hdl, NULL), /* continue */);
+ return ;
+}
+
+EXTENSION_ENTRY("rt_load_balance", rt_load_balance_entry);