(Logical change 1.3)

[mirror_iproute2.git] / tc / tc_red.c

diff --git a/tc/tc_red.c b/tc/tc_red.c
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..385e7af116b399980085cd20b1951b4374551ab2 100644 (file)
--- a/tc/tc_red.c
+++ b/tc/tc_red.c
@@ -0,0 +1,97 @@
+/*
+ * tc_red.c            RED maintanance routines.
+ *
+ *             This program is free software; you can redistribute it and/or
+ *             modify it under the terms of the GNU General Public License
+ *             as published by the Free Software Foundation; either version
+ *             2 of the License, or (at your option) any later version.
+ *
+ * Authors:    Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <math.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+#include "tc_core.h"
+#include "tc_red.h"
+
+/*
+   Plog = log(prob/(qmax - qmin))
+ */
+int tc_red_eval_P(unsigned qmin, unsigned qmax, double prob)
+{
+       int i = qmax - qmin;
+
+       if (i <= 0)
+               return -1;
+
+       prob /= i;
+
+       for (i=0; i<32; i++) {
+               if (prob > 1.0)
+                       break;
+               prob *= 2;
+       }
+       if (i>=32)
+               return -1;
+       return i;
+}
+
+/*
+   burst + 1 - qmin/avpkt < (1-(1-W)^burst)/W
+ */
+
+int tc_red_eval_ewma(unsigned qmin, unsigned burst, unsigned avpkt)
+{
+       int wlog = 1;
+       double W = 0.5;
+       double a = (double)burst + 1 - (double)qmin/avpkt;
+
+       if (a < 1.0)
+               return -1;
+       for (wlog=1; wlog<32; wlog++, W /= 2) {
+               if (a <= (1 - pow(1-W, burst))/W)
+                       return wlog;
+       }
+       return -1;
+}
+
+/*
+   Stab[t>>Scell_log] = -log(1-W) * t/xmit_time
+ */
+
+int tc_red_eval_idle_damping(int Wlog, unsigned avpkt, unsigned bps, __u8 *sbuf)
+{
+       double xmit_time = tc_core_usec2tick(1000000*(double)avpkt/bps);
+       double lW = -log(1.0 - 1.0/(1<<Wlog))/xmit_time;
+       double maxtime = 31/lW;
+       int clog;
+       int i;
+       double tmp;
+
+       tmp = maxtime;
+       for (clog=0; clog<32; clog++) {
+               if (maxtime/(1<<clog) < 512)
+                       break;
+       }
+       if (clog >= 32)
+               return -1;
+
+       sbuf[0] = 0;
+       for (i=1; i<255; i++) {
+               sbuf[i] = (i<<clog)*lW;
+               if (sbuf[i] > 31)
+                       sbuf[i] = 31;
+       }
+       sbuf[255] = 31;
+       return clog;
+}