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authorArnaldo Carvalho de Melo <acme@mandriva.com>2005-08-28 00:47:15 -0300
committerDavid S. Miller <davem@sunset.davemloft.net>2005-08-29 16:12:47 -0700
commit36729c1a73c354a155db18d64d9e79b86c446fcf (patch)
treefea16e7c173151a795d7c617478073e7c36eceb6 /net/dccp/ccids/lib
parent5cea0ddce56ff3406a81fbbab80ef45c65701673 (diff)
[DCCP]: Move the calc_X routines to dccp_tfrc_lib
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/ccids/lib')
-rw-r--r--net/dccp/ccids/lib/Makefile2
-rw-r--r--net/dccp/ccids/lib/tfrc.h22
-rw-r--r--net/dccp/ccids/lib/tfrc_equation.c644
3 files changed, 667 insertions, 1 deletions
diff --git a/net/dccp/ccids/lib/Makefile b/net/dccp/ccids/lib/Makefile
index e9a91e238c8..5f940a6cbac 100644
--- a/net/dccp/ccids/lib/Makefile
+++ b/net/dccp/ccids/lib/Makefile
@@ -1,3 +1,3 @@
obj-$(CONFIG_IP_DCCP_TFRC_LIB) += dccp_tfrc_lib.o
-dccp_tfrc_lib-y := loss_interval.o packet_history.o
+dccp_tfrc_lib-y := loss_interval.o packet_history.o tfrc_equation.o
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
new file mode 100644
index 00000000000..130c4c40cfe
--- /dev/null
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -0,0 +1,22 @@
+#ifndef _TFRC_H_
+#define _TFRC_H_
+/*
+ * net/dccp/ccids/lib/tfrc.h
+ *
+ * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ * Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
+ * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ * 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.
+ */
+
+#include <linux/types.h>
+
+extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
+extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
+
+#endif /* _TFRC_H_ */
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
new file mode 100644
index 00000000000..d2b5933b451
--- /dev/null
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -0,0 +1,644 @@
+/*
+ * net/dccp/ccids/lib/tfrc_equation.c
+ *
+ * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ * Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
+ * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ * 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.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+
+#include <asm/bug.h>
+#include <asm/div64.h>
+
+#include "tfrc.h"
+
+#define TFRC_CALC_X_ARRSIZE 500
+
+#define TFRC_CALC_X_SPLIT 50000
+/* equivalent to 0.05 */
+
+static const u32 tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE][2] = {
+ { 37172, 8172 },
+ { 53499, 11567 },
+ { 66664, 14180 },
+ { 78298, 16388 },
+ { 89021, 18339 },
+ { 99147, 20108 },
+ { 108858, 21738 },
+ { 118273, 23260 },
+ { 127474, 24693 },
+ { 136520, 26052 },
+ { 145456, 27348 },
+ { 154316, 28589 },
+ { 163130, 29783 },
+ { 171919, 30935 },
+ { 180704, 32049 },
+ { 189502, 33130 },
+ { 198328, 34180 },
+ { 207194, 35202 },
+ { 216114, 36198 },
+ { 225097, 37172 },
+ { 234153, 38123 },
+ { 243294, 39055 },
+ { 252527, 39968 },
+ { 261861, 40864 },
+ { 271305, 41743 },
+ { 280866, 42607 },
+ { 290553, 43457 },
+ { 300372, 44293 },
+ { 310333, 45117 },
+ { 320441, 45929 },
+ { 330705, 46729 },
+ { 341131, 47518 },
+ { 351728, 48297 },
+ { 362501, 49066 },
+ { 373460, 49826 },
+ { 384609, 50577 },
+ { 395958, 51320 },
+ { 407513, 52054 },
+ { 419281, 52780 },
+ { 431270, 53499 },
+ { 443487, 54211 },
+ { 455940, 54916 },
+ { 468635, 55614 },
+ { 481581, 56306 },
+ { 494785, 56991 },
+ { 508254, 57671 },
+ { 521996, 58345 },
+ { 536019, 59014 },
+ { 550331, 59677 },
+ { 564939, 60335 },
+ { 579851, 60988 },
+ { 595075, 61636 },
+ { 610619, 62279 },
+ { 626491, 62918 },
+ { 642700, 63553 },
+ { 659253, 64183 },
+ { 676158, 64809 },
+ { 693424, 65431 },
+ { 711060, 66050 },
+ { 729073, 66664 },
+ { 747472, 67275 },
+ { 766266, 67882 },
+ { 785464, 68486 },
+ { 805073, 69087 },
+ { 825103, 69684 },
+ { 845562, 70278 },
+ { 866460, 70868 },
+ { 887805, 71456 },
+ { 909606, 72041 },
+ { 931873, 72623 },
+ { 954614, 73202 },
+ { 977839, 73778 },
+ { 1001557, 74352 },
+ { 1025777, 74923 },
+ { 1050508, 75492 },
+ { 1075761, 76058 },
+ { 1101544, 76621 },
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+ { 1210173, 78852 },
+ { 1238753, 79405 },
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+};
+
+/* Calculate the send rate as per section 3.1 of RFC3448
+
+Returns send rate in bytes per second
+
+Integer maths and lookups are used as not allowed floating point in kernel
+
+The function for Xcalc as per section 3.1 of RFC3448 is:
+
+X = s
+ -------------------------------------------------------------
+ R*sqrt(2*b*p/3) + (t_RTO * (3*sqrt(3*b*p/8) * p * (1+32*p^2)))
+
+where
+X is the trasmit rate in bytes/second
+s is the packet size in bytes
+R is the round trip time in seconds
+p is the loss event rate, between 0 and 1.0, of the number of loss events
+ as a fraction of the number of packets transmitted
+t_RTO is the TCP retransmission timeout value in seconds
+b is the number of packets acknowledged by a single TCP acknowledgement
+
+we can assume that b = 1 and t_RTO is 4 * R. With this the equation becomes:
+
+X = s
+ -----------------------------------------------------------------------
+ R * sqrt(2 * p / 3) + (12 * R * (sqrt(3 * p / 8) * p * (1 + 32 * p^2)))
+
+
+which we can break down into:
+
+X = s
+ --------
+ R * f(p)
+
+where f(p) = sqrt(2 * p / 3) + (12 * sqrt(3 * p / 8) * p * (1 + 32 * p * p))
+
+Function parameters:
+s - bytes
+R - RTT in usecs
+p - loss rate (decimal fraction multiplied by 1,000,000)
+
+Returns Xcalc in bytes per second
+
+DON'T alter this code unless you run test cases against it as the code
+has been manipulated to stop underflow/overlow.
+
+*/
+u32 tfrc_calc_x(u16 s, u32 R, u32 p)
+{
+ int index;
+ u32 f;
+ u64 tmp1, tmp2;
+
+ if (p < TFRC_CALC_X_SPLIT)
+ index = (p / (TFRC_CALC_X_SPLIT / TFRC_CALC_X_ARRSIZE)) - 1;
+ else
+ index = (p / (1000000 / TFRC_CALC_X_ARRSIZE)) - 1;
+
+ if (index < 0)
+ /* p should be 0 unless there is a bug in my code */
+ index = 0;
+
+ if (R == 0)
+ R = 1; /* RTT can't be zero or else divide by zero */
+
+ BUG_ON(index >= TFRC_CALC_X_ARRSIZE);
+
+ if (p >= TFRC_CALC_X_SPLIT)
+ f = tfrc_calc_x_lookup[index][0];
+ else
+ f = tfrc_calc_x_lookup[index][1];
+
+ tmp1 = ((u64)s * 100000000);
+ tmp2 = ((u64)R * (u64)f);
+ do_div(tmp2, 10000);
+ do_div(tmp1, tmp2);
+ /* Don't alter above math unless you test due to overflow on 32 bit */
+
+ return (u32)tmp1;
+}
+
+EXPORT_SYMBOL_GPL(tfrc_calc_x);
+
+/*
+ * args: fvalue - function value to match
+ * returns: p closest to that value
+ *
+ * both fvalue and p are multiplied by 1,000,000 to use ints
+ */
+u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
+{
+ int ctr = 0;
+ int small;
+
+ if (fvalue < tfrc_calc_x_lookup[0][1])
+ return 0;
+
+ if (fvalue <= tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][1])
+ small = 1;
+ else if (fvalue > tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][0])
+ return 1000000;
+ else
+ small = 0;
+
+ while (fvalue > tfrc_calc_x_lookup[ctr][small])
+ ctr++;
+
+ if (small)
+ return TFRC_CALC_X_SPLIT * ctr / TFRC_CALC_X_ARRSIZE;
+ else
+ return 1000000 * ctr / TFRC_CALC_X_ARRSIZE;
+}
+
+EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup);