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-rw-r--r--net/dccp/ccids/ccid3.c624
-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
4 files changed, 672 insertions, 620 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 12548fbde86..a215c46d6f1 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -39,6 +39,7 @@
#include "../dccp.h"
#include "lib/packet_history.h"
#include "lib/loss_interval.h"
+#include "lib/tfrc.h"
#include "ccid3.h"
/*
@@ -112,595 +113,6 @@ static inline void ccid3_hc_tx_set_state(struct sock *sk,
hctx->ccid3hctx_state = state;
}
-#define CALCX_ARRSIZE 500
-
-#define CALCX_SPLIT 50000
-/* equivalent to 0.05 */
-
-static const u32 calcx_lookup[CALCX_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 },
- { 1127867 , 77183 },
- { 1154739 , 77741 },
- { 1182172 , 78298 },
- { 1210173 , 78852 },
- { 1238753 , 79405 },
- { 1267922 , 79955 },
- { 1297689 , 80503 },
- { 1328066 , 81049 },
- { 1359060 , 81593 },
- { 1390684 , 82135 },
- { 1422947 , 82675 },
- { 1455859 , 83213 },
- { 1489430 , 83750 },
- { 1523671 , 84284 },
- { 1558593 , 84817 },
- { 1594205 , 85348 },
- { 1630518 , 85878 },
- { 1667543 , 86406 },
- { 1705290 , 86932 },
- { 1743770 , 87457 },
- { 1782994 , 87980 },
- { 1822973 , 88501 },
- { 1863717 , 89021 },
- { 1905237 , 89540 },
- { 1947545 , 90057 },
- { 1990650 , 90573 },
- { 2034566 , 91087 },
- { 2079301 , 91600 },
- { 2124869 , 92111 },
- { 2171279 , 92622 },
- { 2218543 , 93131 },
- { 2266673 , 93639 },
- { 2315680 , 94145 },
- { 2365575 , 94650 },
- { 2416371 , 95154 },
- { 2468077 , 95657 },
- { 2520707 , 96159 },
- { 2574271 , 96660 },
- { 2628782 , 97159 },
- { 2684250 , 97658 },
- { 2740689 , 98155 },
- { 2798110 , 98651 },
- { 2856524 , 99147 },
- { 2915944 , 99641 },
- { 2976382 , 100134 },
- { 3037850 , 100626 },
- { 3100360 , 101117 },
- { 3163924 , 101608 },
- { 3228554 , 102097 },
- { 3294263 , 102586 },
- { 3361063 , 103073 },
- { 3428966 , 103560 },
- { 3497984 , 104045 },
- { 3568131 , 104530 },
- { 3639419 , 105014 },
- { 3711860 , 105498 },
- { 3785467 , 105980 },
- { 3860253 , 106462 },
- { 3936229 , 106942 },
- { 4013410 , 107422 },
- { 4091808 , 107902 },
- { 4171435 , 108380 },
- { 4252306 , 108858 },
- { 4334431 , 109335 },
- { 4417825 , 109811 },
- { 4502501 , 110287 },
- { 4588472 , 110762 },
- { 4675750 , 111236 },
- { 4764349 , 111709 },
- { 4854283 , 112182 },
- { 4945564 , 112654 },
- { 5038206 , 113126 },
- { 5132223 , 113597 },
- { 5227627 , 114067 },
- { 5324432 , 114537 },
- { 5422652 , 115006 },
- { 5522299 , 115474 },
- { 5623389 , 115942 },
- { 5725934 , 116409 },
- { 5829948 , 116876 },
- { 5935446 , 117342 },
- { 6042439 , 117808 },
- { 6150943 , 118273 },
- { 6260972 , 118738 },
- { 6372538 , 119202 },
- { 6485657 , 119665 },
- { 6600342 , 120128 },
- { 6716607 , 120591 },
- { 6834467 , 121053 },
- { 6953935 , 121514 },
- { 7075025 , 121976 },
- { 7197752 , 122436 },
- { 7322131 , 122896 },
- { 7448175 , 123356 },
- { 7575898 , 123815 },
- { 7705316 , 124274 },
- { 7836442 , 124733 },
- { 7969291 , 125191 },
- { 8103877 , 125648 },
- { 8240216 , 126105 },
- { 8378321 , 126562 },
- { 8518208 , 127018 },
- { 8659890 , 127474 },
- { 8803384 , 127930 },
- { 8948702 , 128385 },
- { 9095861 , 128840 },
- { 9244875 , 129294 },
- { 9395760 , 129748 },
- { 9548529 , 130202 },
- { 9703198 , 130655 },
- { 9859782 , 131108 },
- { 10018296 , 131561 },
- { 10178755 , 132014 },
- { 10341174 , 132466 },
- { 10505569 , 132917 },
- { 10671954 , 133369 },
- { 10840345 , 133820 },
- { 11010757 , 134271 },
- { 11183206 , 134721 },
- { 11357706 , 135171 },
- { 11534274 , 135621 },
- { 11712924 , 136071 },
- { 11893673 , 136520 },
- { 12076536 , 136969 },
- { 12261527 , 137418 },
- { 12448664 , 137867 },
- { 12637961 , 138315 },
- { 12829435 , 138763 },
- { 13023101 , 139211 },
- { 13218974 , 139658 },
- { 13417071 , 140106 },
- { 13617407 , 140553 },
- { 13819999 , 140999 },
- { 14024862 , 141446 },
- { 14232012 , 141892 },
- { 14441465 , 142339 },
- { 14653238 , 142785 },
- { 14867346 , 143230 },
- { 15083805 , 143676 },
- { 15302632 , 144121 },
- { 15523842 , 144566 },
- { 15747453 , 145011 },
- { 15973479 , 145456 },
- { 16201939 , 145900 },
- { 16432847 , 146345 },
- { 16666221 , 146789 },
- { 16902076 , 147233 },
- { 17140429 , 147677 },
- { 17381297 , 148121 },
- { 17624696 , 148564 },
- { 17870643 , 149007 },
- { 18119154 , 149451 },
- { 18370247 , 149894 },
- { 18623936 , 150336 },
- { 18880241 , 150779 },
- { 19139176 , 151222 },
- { 19400759 , 151664 },
- { 19665007 , 152107 },
- { 19931936 , 152549 },
- { 20201564 , 152991 },
- { 20473907 , 153433 },
- { 20748982 , 153875 },
- { 21026807 , 154316 },
- { 21307399 , 154758 },
- { 21590773 , 155199 },
- { 21876949 , 155641 },
- { 22165941 , 156082 },
- { 22457769 , 156523 },
- { 22752449 , 156964 },
- { 23049999 , 157405 },
- { 23350435 , 157846 },
- { 23653774 , 158287 },
- { 23960036 , 158727 },
- { 24269236 , 159168 },
- { 24581392 , 159608 },
- { 24896521 , 160049 },
- { 25214642 , 160489 },
- { 25535772 , 160929 },
- { 25859927 , 161370 },
- { 26187127 , 161810 },
- { 26517388 , 162250 },
- { 26850728 , 162690 },
- { 27187165 , 163130 },
- { 27526716 , 163569 },
- { 27869400 , 164009 },
- { 28215234 , 164449 },
- { 28564236 , 164889 },
- { 28916423 , 165328 },
- { 29271815 , 165768 },
- { 29630428 , 166208 },
- { 29992281 , 166647 },
- { 30357392 , 167087 },
- { 30725779 , 167526 },
- { 31097459 , 167965 },
- { 31472452 , 168405 },
- { 31850774 , 168844 },
- { 32232445 , 169283 },
- { 32617482 , 169723 },
- { 33005904 , 170162 },
- { 33397730 , 170601 },
- { 33792976 , 171041 },
- { 34191663 , 171480 },
- { 34593807 , 171919 },
- { 34999428 , 172358 },
- { 35408544 , 172797 },
- { 35821174 , 173237 },
- { 36237335 , 173676 },
- { 36657047 , 174115 },
- { 37080329 , 174554 },
- { 37507197 , 174993 },
- { 37937673 , 175433 },
- { 38371773 , 175872 },
- { 38809517 , 176311 },
- { 39250924 , 176750 },
- { 39696012 , 177190 },
- { 40144800 , 177629 },
- { 40597308 , 178068 },
- { 41053553 , 178507 },
- { 41513554 , 178947 },
- { 41977332 , 179386 },
- { 42444904 , 179825 },
- { 42916290 , 180265 },
- { 43391509 , 180704 },
- { 43870579 , 181144 },
- { 44353520 , 181583 },
- { 44840352 , 182023 },
- { 45331092 , 182462 },
- { 45825761 , 182902 },
- { 46324378 , 183342 },
- { 46826961 , 183781 },
- { 47333531 , 184221 },
- { 47844106 , 184661 },
- { 48358706 , 185101 },
- { 48877350 , 185541 },
- { 49400058 , 185981 },
- { 49926849 , 186421 },
- { 50457743 , 186861 },
- { 50992759 , 187301 },
- { 51531916 , 187741 },
- { 52075235 , 188181 },
- { 52622735 , 188622 },
- { 53174435 , 189062 },
- { 53730355 , 189502 },
- { 54290515 , 189943 },
- { 54854935 , 190383 },
- { 55423634 , 190824 },
- { 55996633 , 191265 },
- { 56573950 , 191706 },
- { 57155606 , 192146 },
- { 57741621 , 192587 },
- { 58332014 , 193028 },
- { 58926806 , 193470 },
- { 59526017 , 193911 },
- { 60129666 , 194352 },
- { 60737774 , 194793 },
- { 61350361 , 195235 },
- { 61967446 , 195677 },
- { 62589050 , 196118 },
- { 63215194 , 196560 },
- { 63845897 , 197002 },
- { 64481179 , 197444 },
- { 65121061 , 197886 },
- { 65765563 , 198328 },
- { 66414705 , 198770 },
- { 67068508 , 199213 },
- { 67726992 , 199655 },
- { 68390177 , 200098 },
- { 69058085 , 200540 },
- { 69730735 , 200983 },
- { 70408147 , 201426 },
- { 71090343 , 201869 },
- { 71777343 , 202312 },
- { 72469168 , 202755 },
- { 73165837 , 203199 },
- { 73867373 , 203642 },
- { 74573795 , 204086 },
- { 75285124 , 204529 },
- { 76001380 , 204973 },
- { 76722586 , 205417 },
- { 77448761 , 205861 },
- { 78179926 , 206306 },
- { 78916102 , 206750 },
- { 79657310 , 207194 },
- { 80403571 , 207639 },
- { 81154906 , 208084 },
- { 81911335 , 208529 },
- { 82672880 , 208974 },
- { 83439562 , 209419 },
- { 84211402 , 209864 },
- { 84988421 , 210309 },
- { 85770640 , 210755 },
- { 86558080 , 211201 },
- { 87350762 , 211647 },
- { 88148708 , 212093 },
- { 88951938 , 212539 },
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- { 90574339 , 213432 },
- { 91393551 , 213878 },
- { 92218133 , 214325 },
- { 93048107 , 214772 },
- { 93883493 , 215219 },
- { 94724314 , 215666 },
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- { 98142366 , 217457 },
- { 99010679 , 217905 },
- { 99884556 , 218353 },
- { 100764018 , 218801 },
- { 101649086 , 219250 },
- { 102539782 , 219698 },
- { 103436128 , 220147 },
- { 104338146 , 220596 },
- { 105245857 , 221046 },
- { 106159284 , 221495 },
- { 107078448 , 221945 },
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- { 109870580 , 223294 },
- { 110812910 , 223745 },
- { 111761087 , 224195 },
- { 112715133 , 224646 },
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- { 115612702 , 225999 },
- { 116590442 , 226450 },
- { 117574162 , 226902 },
- { 118563882 , 227353 },
- { 119559626 , 227805 },
- { 120561415 , 228258 },
- { 121569272 , 228710 },
- { 122583219 , 229162 },
- { 123603278 , 229615 },
- { 124629471 , 230068 },
- { 125661822 , 230521 },
- { 126700352 , 230974 },
- { 127745083 , 231428 },
- { 128796039 , 231882 },
- { 129853241 , 232336 },
- { 130916713 , 232790 },
- { 131986475 , 233244 },
- { 133062553 , 233699 },
- { 134144966 , 234153 },
- { 135233739 , 234608 },
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- { 137430453 , 235519 },
- { 138538440 , 235975 },
- { 139652876 , 236430 },
- { 140773786 , 236886 },
- { 141901190 , 237343 },
- { 143035113 , 237799 },
- { 144175576 , 238256 },
- { 145322604 , 238713 },
- { 146476218 , 239170 },
- { 147636442 , 239627 },
- { 148803298 , 240085 },
- { 149976809 , 240542 },
- { 151156999 , 241000 },
- { 152343890 , 241459 },
- { 153537506 , 241917 },
- { 154737869 , 242376 },
- { 155945002 , 242835 },
- { 157158929 , 243294 },
- { 158379673 , 243753 },
- { 159607257 , 244213 },
- { 160841704 , 244673 },
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- { 163331279 , 245593 },
- { 164586455 , 246054 },
- { 165848586 , 246514 },
- { 167117696 , 246975 },
- { 168393810 , 247437 },
- { 169676949 , 247898 },
- { 170967138 , 248360 },
- { 172264399 , 248822 },
- { 173568757 , 249284 },
- { 174880235 , 249747 },
- { 176198856 , 250209 },
- { 177524643 , 250672 },
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- { 180197813 , 251599 },
- { 181545242 , 252063 },
- { 182899933 , 252527 },
- { 184261908 , 252991 },
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- { 187007807 , 253920 },
- { 188391778 , 254385 },
- { 189783129 , 254851 },
- { 191181884 , 255316 },
- { 192588065 , 255782 },
- { 194001698 , 256248 },
- { 195422805 , 256714 },
- { 196851411 , 257181 },
- { 198287540 , 257648 },
- { 199731215 , 258115 },
- { 201182461 , 258582 },
- { 202641302 , 259050 },
- { 204107760 , 259518 },
- { 205581862 , 259986 },
- { 207063630 , 260454 },
- { 208553088 , 260923 },
- { 210050262 , 261392 },
- { 211555174 , 261861 },
- { 213067849 , 262331 },
- { 214588312 , 262800 },
- { 216116586 , 263270 },
- { 217652696 , 263741 },
- { 219196666 , 264211 },
- { 220748520 , 264682 },
- { 222308282 , 265153 },
- { 223875978 , 265625 },
- { 225451630 , 266097 },
- { 227035265 , 266569 },
- { 228626905 , 267041 },
- { 230226576 , 267514 },
- { 231834302 , 267986 },
- { 233450107 , 268460 },
- { 235074016 , 268933 },
- { 236706054 , 269407 },
- { 238346244 , 269881 },
- { 239994613 , 270355 },
- { 241651183 , 270830 },
- { 243315981 , 271305 }
-};
-
-/* 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.
-
-*/
-static u32 ccid3_calc_x(u16 s, u32 R, u32 p)
-{
- int index;
- u32 f;
- u64 tmp1, tmp2;
-
- if (p < CALCX_SPLIT)
- index = (p / (CALCX_SPLIT / CALCX_ARRSIZE)) - 1;
- else
- index = (p / (1000000 / CALCX_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 >= CALCX_ARRSIZE);
-
- if (p >= CALCX_SPLIT)
- f = calcx_lookup[index][0];
- else
- f = calcx_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;
-}
-
/* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
{
@@ -737,9 +149,9 @@ static void ccid3_hc_tx_update_x(struct sock *sk)
/* To avoid large error in calcX */
if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
- hctx->ccid3hctx_x_calc = ccid3_calc_x(hctx->ccid3hctx_s,
- hctx->ccid3hctx_rtt,
- hctx->ccid3hctx_p);
+ hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
+ hctx->ccid3hctx_rtt,
+ hctx->ccid3hctx_p);
hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
2 * hctx->ccid3hctx_x_recv),
(hctx->ccid3hctx_s /
@@ -1533,32 +945,6 @@ static void ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
&x_recv, sizeof(x_recv));
}
-/*
- * 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
- */
-static u32 calcx_reverse_lookup(u32 fvalue) {
- int ctr = 0;
- int small;
-
- if (fvalue < calcx_lookup[0][1])
- return 0;
- if (fvalue <= calcx_lookup[CALCX_ARRSIZE-1][1])
- small = 1;
- else if (fvalue > calcx_lookup[CALCX_ARRSIZE-1][0])
- return 1000000;
- else
- small = 0;
- while (fvalue > calcx_lookup[ctr][small])
- ctr++;
- if (small)
- return (CALCX_SPLIT * ctr / CALCX_ARRSIZE);
- else
- return (1000000 * ctr / CALCX_ARRSIZE) ;
-}
-
/* calculate first loss interval
*
* returns estimated loss interval in usecs */
@@ -1627,7 +1013,7 @@ found:
tmp2 = (u32)tmp1;
fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
/* do not alter order above or you will get overflow on 32 bit */
- p = calcx_reverse_lookup(fval);
+ p = tfrc_calc_x_reverse_lookup(fval);
ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
"loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
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 },
+ { 1127867, 77183 },
+ { 1154739, 77741 },
+ { 1182172, 78298 },
+ { 1210173, 78852 },
+ { 1238753, 79405 },
+ { 1267922, 79955 },
+ { 1297689, 80503 },
+ { 1328066, 81049 },
+ { 1359060, 81593 },
+ { 1390684, 82135 },
+ { 1422947, 82675 },
+ { 1455859, 83213 },
+ { 1489430, 83750 },
+ { 1523671, 84284 },
+ { 1558593, 84817 },
+ { 1594205, 85348 },
+ { 1630518, 85878 },
+ { 1667543, 86406 },
+ { 1705290, 86932 },
+ { 1743770, 87457 },
+ { 1782994, 87980 },
+ { 1822973, 88501 },
+ { 1863717, 89021 },
+ { 1905237, 89540 },
+ { 1947545, 90057 },
+ { 1990650, 90573 },
+ { 2034566, 91087 },
+ { 2079301, 91600 },
+ { 2124869, 92111 },
+ { 2171279, 92622 },
+ { 2218543, 93131 },
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+ { 2315680, 94145 },
+ { 2365575, 94650 },
+ { 2416371, 95154 },
+ { 2468077, 95657 },
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+ { 2684250, 97658 },
+ { 2740689, 98155 },
+ { 2798110, 98651 },
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+ { 3037850, 100626 },
+ { 3100360, 101117 },
+ { 3163924, 101608 },
+ { 3228554, 102097 },
+ { 3294263, 102586 },
+ { 3361063, 103073 },
+ { 3428966, 103560 },
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+ { 3568131, 104530 },
+ { 3639419, 105014 },
+ { 3711860, 105498 },
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+ { 4334431, 109335 },
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+ { 4675750, 111236 },
+ { 4764349, 111709 },
+ { 4854283, 112182 },
+ { 4945564, 112654 },
+ { 5038206, 113126 },
+ { 5132223, 113597 },
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+ { 5422652, 115006 },
+ { 5522299, 115474 },
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+ { 6150943, 118273 },
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+ { 7075025, 121976 },
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+ { 24896521, 160049 },
+ { 25214642, 160489 },
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+ { 26517388, 162250 },
+ { 26850728, 162690 },
+ { 27187165, 163130 },
+ { 27526716, 163569 },
+ { 27869400, 164009 },
+ { 28215234, 164449 },
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+ { 28916423, 165328 },
+ { 29271815, 165768 },
+ { 29630428, 166208 },
+ { 29992281, 166647 },
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+ { 243315981, 271305 }
+};
+
+/* 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);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-27 22:28:05 +0000