[PKT_SCHED]: Update for netem scheduler.

This is a third revision of the netem extensions which provides
	* packet duplication
	* correlated random number
	* loading distribution table

The API is backwards compatible and now uses nested elements to allow
for easier future changes.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/pkt_sched.h

@@ -402,6 +402,16 @@ enum {
 #define TCA_ATM_MAX	TCA_ATM_STATE
 
 /* Network emulator */
+
+enum
+{
+	TCA_NETEM_UNSPEC,
+	TCA_NETEM_CORR,
+	TCA_NETEM_DELAY_DIST,
+};
+
+#define TCA_NETEM_MAX	TCA_NETEM_DELAY_DIST
+
 struct tc_netem_qopt
 {
 	__u32	latency;	/* added delay (us) */
@@ -411,4 +421,19 @@ struct tc_netem_qopt
 	__u32   duplicate;	/* random packet dup  (0=none ~0=100%) */
 	__u32	jitter;		/* random jitter in latency (us) */
 };
+
+struct tc_netem_corr
+{
+	__u32	delay_corr;	/* delay correlation */
+	__u32	loss_corr;	/* packet loss correlation */
+	__u32	dup_corr;	/* duplicate correlation  */
+};
+
+struct tc_netem_dist
+{
+	__u32	size;		/* table size */
+	__u32	factor;		/* table scaling factor */
+	__s16	data[0];	/* distribution table values */
+};
+
 #endif

net/sched/sch_netem.c

@@ -6,6 +6,9 @@
  * 		as published by the Free Software Foundation; either version
  * 		2 of the License, or (at your option) any later version.
  *
+ *  		Many of the algorithms and ideas for this came from
+ *		NIST Net which is not copyrighted. 
+ *
  * Authors:	Stephen Hemminger <shemminger@osdl.org>
  *		Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
  */
@@ -22,11 +25,31 @@
 
 #include <net/pkt_sched.h>
 
-/*	Network emulator
- *
- *	This scheduler can alters spacing and order
- *	Similar to NISTnet and BSD Dummynet.
- */
+/*	Network Emulation Queuing algorithm.
+	====================================
+
+	Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
+		 Network Emulation Tool
+		 [2] Luigi Rizzo, DummyNet for FreeBSD
+
+	 ----------------------------------------------------------------
+
+	 This started out as a simple way to delay outgoing packets to
+	 test TCP but has grown to include most of the functionality
+	 of a full blown network emulator like NISTnet. It can delay
+	 packets and add random jitter (and correlation). The random
+	 distribution can be loaded from a table as well to provide
+	 normal, Pareto, or experimental curves. Packet loss,
+	 duplication, and reordering can also be emulated.
+
+	 This qdisc does not do classification that can be handled in
+	 layering other disciplines.  It does not need to do bandwidth
+	 control either since that can be handled by using token
+	 bucket or other rate control.
+
+	 The simulator is limited by the Linux timer resolution
+	 and will create packet bursts on the HZ boundary (1ms).
+*/
 
 struct netem_sched_data {
 	struct Qdisc	*qdisc;
@@ -39,6 +62,18 @@ struct netem_sched_data {
 	u32 counter;
 	u32 gap;
 	u32 jitter;
+	u32 duplicate;
+
+	struct crndstate {
+		unsigned long last;
+		unsigned long rho;
+	} delay_cor, loss_cor, dup_cor;
+
+	struct disttable {
+		u32  size;
+		u32  factor;
+		s16 table[0];
+	} *delay_dist;
 };
 
 /* Time stamp put into socket buffer control block */
@@ -46,576 +81,113 @@ struct netem_skb_cb {
 	psched_time_t	time_to_send;
 };
 
-/* This is the distribution table for the normal distribution produced
- * with NISTnet tools.
- * The entries represent a scaled inverse of the cumulative distribution
- * function.
+/* init_crandom - initialize correlated random number generator
+ * Use entropy source for initial seed.
  */
-#define TABLESIZE	2048
-#define TABLEFACTOR	8192
-
-static const short disttable[TABLESIZE] = {
-	-31473,		-26739,		-25226,		-24269,
-	-23560,		-22993,		-22518,		-22109,
-	-21749,		-21426,		-21133,		-20865,
-	-20618,		-20389,		-20174,		-19972,
-	-19782,		-19601,		-19430,		-19267,
-	-19112,		-18962,		-18819,		-18681,
-	-18549,		-18421,		-18298,		-18178,
-	-18062,		-17950,		-17841,		-17735,
-	-17632,		-17532,		-17434,		-17339,
-	-17245,		-17155,		-17066,		-16979,
-	-16894,		-16811,		-16729,		-16649,
-	-16571,		-16494,		-16419,		-16345,
-	-16272,		-16201,		-16130,		-16061,
-	-15993,		-15926,		-15861,		-15796,
-	-15732,		-15669,		-15607,		-15546,
-	-15486,		-15426,		-15368,		-15310,
-	-15253,		-15196,		-15140,		-15086,
-	-15031,		-14977,		-14925,		-14872,
-	-14821,		-14769,		-14719,		-14669,
-	-14619,		-14570,		-14522,		-14473,
-	-14426,		-14379,		-14332,		-14286,
-	-14241,		-14196,		-14150,		-14106,
-	-14062,		-14019,		-13976,		-13933,
-	-13890,		-13848,		-13807,		-13765,
-	-13724,		-13684,		-13643,		-13604,
-	-13564,		-13525,		-13486,		-13447,
-	-13408,		-13370,		-13332,		-13295,
-	-13258,		-13221,		-13184,		-13147,
-	-13111,		-13075,		-13040,		-13004,
-	-12969,		-12934,		-12899,		-12865,
-	-12830,		-12796,		-12762,		-12729,
-	-12695,		-12662,		-12629,		-12596,
-	-12564,		-12531,		-12499,		-12467,
-	-12435,		-12404,		-12372,		-12341,
-	-12310,		-12279,		-12248,		-12218,
-	-12187,		-12157,		-12127,		-12097,
-	-12067,		-12038,		-12008,		-11979,
-	-11950,		-11921,		-11892,		-11863,
-	-11835,		-11806,		-11778,		-11750,
-	-11722,		-11694,		-11666,		-11639,
-	-11611,		-11584,		-11557,		-11530,
-	-11503,		-11476,		-11450,		-11423,
-	-11396,		-11370,		-11344,		-11318,
-	-11292,		-11266,		-11240,		-11214,
-	-11189,		-11164,		-11138,		-11113,
-	-11088,		-11063,		-11038,		-11013,
-	-10988,		-10964,		-10939,		-10915,
-	-10891,		-10866,		-10843,		-10818,
-	-10794,		-10770,		-10747,		-10723,
-	-10700,		-10676,		-10652,		-10630,
-	-10606,		-10583,		-10560,		-10537,
-	-10514,		-10491,		-10469,		-10446,
-	-10424,		-10401,		-10378,		-10356,
-	-10334,		-10312,		-10290,		-10267,
-	-10246,		-10224,		-10202,		-10180,
-	-10158,		-10137,		-10115,		-10094,
-	-10072,		-10051,		-10030,		-10009,
-	-9988,		-9967,		-9945,		-9925,
-	-9904,		-9883,		-9862,		-9842,
-	-9821,		-9800,		-9780,		-9760,
-	-9739,		-9719,		-9699,		-9678,
-	-9658,		-9638,		-9618,		-9599,
-	-9578,		-9559,		-9539,		-9519,
-	-9499,		-9480,		-9461,		-9441,
-	-9422,		-9402,		-9383,		-9363,
-	-9344,		-9325,		-9306,		-9287,
-	-9268,		-9249,		-9230,		-9211,
-	-9192,		-9173,		-9155,		-9136,
-	-9117,		-9098,		-9080,		-9062,
-	-9043,		-9025,		-9006,		-8988,
-	-8970,		-8951,		-8933,		-8915,
-	-8897,		-8879,		-8861,		-8843,
-	-8825,		-8807,		-8789,		-8772,
-	-8754,		-8736,		-8718,		-8701,
-	-8683,		-8665,		-8648,		-8630,
-	-8613,		-8595,		-8578,		-8561,
-	-8543,		-8526,		-8509,		-8492,
-	-8475,		-8458,		-8441,		-8423,
-	-8407,		-8390,		-8373,		-8356,
-	-8339,		-8322,		-8305,		-8289,
-	-8272,		-8255,		-8239,		-8222,
-	-8206,		-8189,		-8172,		-8156,
-	-8140,		-8123,		-8107,		-8090,
-	-8074,		-8058,		-8042,		-8025,
-	-8009,		-7993,		-7977,		-7961,
-	-7945,		-7929,		-7913,		-7897,
-	-7881,		-7865,		-7849,		-7833,
-	-7817,		-7802,		-7786,		-7770,
-	-7754,		-7739,		-7723,		-7707,
-	-7692,		-7676,		-7661,		-7645,
-	-7630,		-7614,		-7599,		-7583,
-	-7568,		-7553,		-7537,		-7522,
-	-7507,		-7492,		-7476,		-7461,
-	-7446,		-7431,		-7416,		-7401,
-	-7385,		-7370,		-7356,		-7340,
-	-7325,		-7311,		-7296,		-7281,
-	-7266,		-7251,		-7236,		-7221,
-	-7207,		-7192,		-7177,		-7162,
-	-7148,		-7133,		-7118,		-7104,
-	-7089,		-7075,		-7060,		-7046,
-	-7031,		-7016,		-7002,		-6988,
-	-6973,		-6959,		-6944,		-6930,
-	-6916,		-6901,		-6887,		-6873,
-	-6859,		-6844,		-6830,		-6816,
-	-6802,		-6788,		-6774,		-6760,
-	-6746,		-6731,		-6717,		-6704,
-	-6690,		-6675,		-6661,		-6647,
-	-6633,		-6620,		-6606,		-6592,
-	-6578,		-6564,		-6550,		-6537,
-	-6523,		-6509,		-6495,		-6482,
-	-6468,		-6454,		-6441,		-6427,
-	-6413,		-6400,		-6386,		-6373,
-	-6359,		-6346,		-6332,		-6318,
-	-6305,		-6291,		-6278,		-6264,
-	-6251,		-6238,		-6224,		-6211,
-	-6198,		-6184,		-6171,		-6158,
-	-6144,		-6131,		-6118,		-6105,
-	-6091,		-6078,		-6065,		-6052,
-	-6039,		-6025,		-6012,		-5999,
-	-5986,		-5973,		-5960,		-5947,
-	-5934,		-5921,		-5908,		-5895,
-	-5882,		-5869,		-5856,		-5843,
-	-5830,		-5817,		-5804,		-5791,
-	-5779,		-5766,		-5753,		-5740,
-	-5727,		-5714,		-5702,		-5689,
-	-5676,		-5663,		-5650,		-5638,
-	-5625,		-5612,		-5600,		-5587,
-	-5575,		-5562,		-5549,		-5537,
-	-5524,		-5512,		-5499,		-5486,
-	-5474,		-5461,		-5449,		-5436,
-	-5424,		-5411,		-5399,		-5386,
-	-5374,		-5362,		-5349,		-5337,
-	-5324,		-5312,		-5299,		-5287,
-	-5275,		-5263,		-5250,		-5238,
-	-5226,		-5213,		-5201,		-5189,
-	-5177,		-5164,		-5152,		-5140,
-	-5128,		-5115,		-5103,		-5091,
-	-5079,		-5067,		-5055,		-5043,
-	-5030,		-5018,		-5006,		-4994,
-	-4982,		-4970,		-4958,		-4946,
-	-4934,		-4922,		-4910,		-4898,
-	-4886,		-4874,		-4862,		-4850,
-	-4838,		-4826,		-4814,		-4803,
-	-4791,		-4778,		-4767,		-4755,
-	-4743,		-4731,		-4719,		-4708,
-	-4696,		-4684,		-4672,		-4660,
-	-4649,		-4637,		-4625,		-4613,
-	-4601,		-4590,		-4578,		-4566,
-	-4554,		-4543,		-4531,		-4520,
-	-4508,		-4496,		-4484,		-4473,
-	-4461,		-4449,		-4438,		-4427,
-	-4415,		-4403,		-4392,		-4380,
-	-4368,		-4357,		-4345,		-4334,
-	-4322,		-4311,		-4299,		-4288,
-	-4276,		-4265,		-4253,		-4242,
-	-4230,		-4219,		-4207,		-4196,
-	-4184,		-4173,		-4162,		-4150,
-	-4139,		-4128,		-4116,		-4105,
-	-4094,		-4082,		-4071,		-4060,
-	-4048,		-4037,		-4026,		-4014,
-	-4003,		-3992,		-3980,		-3969,
-	-3958,		-3946,		-3935,		-3924,
-	-3913,		-3901,		-3890,		-3879,
-	-3868,		-3857,		-3845,		-3834,
-	-3823,		-3812,		-3801,		-3790,
-	-3779,		-3767,		-3756,		-3745,
-	-3734,		-3723,		-3712,		-3700,
-	-3689,		-3678,		-3667,		-3656,
-	-3645,		-3634,		-3623,		-3612,
-	-3601,		-3590,		-3579,		-3568,
-	-3557,		-3545,		-3535,		-3524,
-	-3513,		-3502,		-3491,		-3480,
-	-3469,		-3458,		-3447,		-3436,
-	-3425,		-3414,		-3403,		-3392,
-	-3381,		-3370,		-3360,		-3348,
-	-3337,		-3327,		-3316,		-3305,
-	-3294,		-3283,		-3272,		-3262,
-	-3251,		-3240,		-3229,		-3218,
-	-3207,		-3197,		-3185,		-3175,
-	-3164,		-3153,		-3142,		-3132,
-	-3121,		-3110,		-3099,		-3088,
-	-3078,		-3067,		-3056,		-3045,
-	-3035,		-3024,		-3013,		-3003,
-	-2992,		-2981,		-2970,		-2960,
-	-2949,		-2938,		-2928,		-2917,
-	-2906,		-2895,		-2885,		-2874,
-	-2864,		-2853,		-2842,		-2832,
-	-2821,		-2810,		-2800,		-2789,
-	-2778,		-2768,		-2757,		-2747,
-	-2736,		-2725,		-2715,		-2704,
-	-2694,		-2683,		-2673,		-2662,
-	-2651,		-2641,		-2630,		-2620,
-	-2609,		-2599,		-2588,		-2578,
-	-2567,		-2556,		-2546,		-2535,
-	-2525,		-2515,		-2504,		-2493,
-	-2483,		-2472,		-2462,		-2451,
-	-2441,		-2431,		-2420,		-2410,
-	-2399,		-2389,		-2378,		-2367,
-	-2357,		-2347,		-2336,		-2326,
-	-2315,		-2305,		-2295,		-2284,
-	-2274,		-2263,		-2253,		-2243,
-	-2232,		-2222,		-2211,		-2201,
-	-2191,		-2180,		-2170,		-2159,
-	-2149,		-2139,		-2128,		-2118,
-	-2107,		-2097,		-2087,		-2076,
-	-2066,		-2056,		-2046,		-2035,
-	-2025,		-2014,		-2004,		-1994,
-	-1983,		-1973,		-1963,		-1953,
-	-1942,		-1932,		-1921,		-1911,
-	-1901,		-1891,		-1880,		-1870,
-	-1860,		-1849,		-1839,		-1829,
-	-1819,		-1808,		-1798,		-1788,
-	-1778,		-1767,		-1757,		-1747,
-	-1736,		-1726,		-1716,		-1706,
-	-1695,		-1685,		-1675,		-1665,
-	-1654,		-1644,		-1634,		-1624,
-	-1613,		-1603,		-1593,		-1583,
-	-1573,		-1563,		-1552,		-1542,
-	-1532,		-1522,		-1511,		-1501,
-	-1491,		-1481,		-1471,		-1461,
-	-1450,		-1440,		-1430,		-1420,
-	-1409,		-1400,		-1389,		-1379,
-	-1369,		-1359,		-1348,		-1339,
-	-1328,		-1318,		-1308,		-1298,
-	-1288,		-1278,		-1267,		-1257,
-	-1247,		-1237,		-1227,		-1217,
-	-1207,		-1196,		-1186,		-1176,
-	-1166,		-1156,		-1146,		-1135,
-	-1126,		-1115,		-1105,		-1095,
-	-1085,		-1075,		-1065,		-1055,
-	-1044,		-1034,		-1024,		-1014,
-	-1004,		-994,		-984,		-974,
-	-964,		-954,		-944,		-933,
-	-923,		-913,		-903,		-893,
-	-883,		-873,		-863,		-853,
-	-843,		-833,		-822,		-812,
-	-802,		-792,		-782,		-772,
-	-762,		-752,		-742,		-732,
-	-722,		-712,		-702,		-691,
-	-682,		-671,		-662,		-651,
-	-641,		-631,		-621,		-611,
-	-601,		-591,		-581,		-571,
-	-561,		-551,		-541,		-531,
-	-521,		-511,		-501,		-491,
-	-480,		-471,		-460,		-451,
-	-440,		-430,		-420,		-410,
-	-400,		-390,		-380,		-370,
-	-360,		-350,		-340,		-330,
-	-320,		-310,		-300,		-290,
-	-280,		-270,		-260,		-250,
-	-240,		-230,		-220,		-210,
-	-199,		-190,		-179,		-170,
-	-159,		-150,		-139,		-129,
-	-119,		-109,		-99,		-89,
-	-79,		-69,		-59,		-49,
-	-39,		-29,		-19,		-9,
-	1,		11,		21,		31,
-	41,		51,		61,		71,
-	81,		91,		101,		111,
-	121,		131,		141,		152,
-	161,		172,		181,		192,
-	202,		212,		222,		232,
-	242,		252,		262,		272,
-	282,		292,		302,		312,
-	322,		332,		342,		352,
-	362,		372,		382,		392,
-	402,		412,		422,		433,
-	442,		453,		462,		473,
-	483,		493,		503,		513,
-	523,		533,		543,		553,
-	563,		573,		583,		593,
-	603,		613,		623,		633,
-	643,		653,		664,		673,
-	684,		694,		704,		714,
-	724,		734,		744,		754,
-	764,		774,		784,		794,
-	804,		815,		825,		835,
-	845,		855,		865,		875,
-	885,		895,		905,		915,
-	925,		936,		946,		956,
-	966,		976,		986,		996,
-	1006,		1016,		1026,		1037,
-	1047,		1057,		1067,		1077,
-	1087,		1097,		1107,		1117,
-	1128,		1138,		1148,		1158,
-	1168,		1178,		1188,		1198,
-	1209,		1219,		1229,		1239,
-	1249,		1259,		1269,		1280,
-	1290,		1300,		1310,		1320,
-	1330,		1341,		1351,		1361,
-	1371,		1381,		1391,		1402,
-	1412,		1422,		1432,		1442,
-	1452,		1463,		1473,		1483,
-	1493,		1503,		1513,		1524,
-	1534,		1544,		1554,		1565,
-	1575,		1585,		1595,		1606,
-	1616,		1626,		1636,		1647,
-	1656,		1667,		1677,		1687,
-	1697,		1708,		1718,		1729,
-	1739,		1749,		1759,		1769,
-	1780,		1790,		1800,		1810,
-	1821,		1831,		1841,		1851,
-	1862,		1872,		1883,		1893,
-	1903,		1913,		1923,		1934,
-	1944,		1955,		1965,		1975,
-	1985,		1996,		2006,		2016,
-	2027,		2037,		2048,		2058,
-	2068,		2079,		2089,		2099,
-	2110,		2120,		2130,		2141,
-	2151,		2161,		2172,		2182,
-	2193,		2203,		2213,		2224,
-	2234,		2245,		2255,		2265,
-	2276,		2286,		2297,		2307,
-	2318,		2328,		2338,		2349,
-	2359,		2370,		2380,		2391,
-	2401,		2412,		2422,		2433,
-	2443,		2454,		2464,		2475,
-	2485,		2496,		2506,		2517,
-	2527,		2537,		2548,		2559,
-	2569,		2580,		2590,		2601,
-	2612,		2622,		2632,		2643,
-	2654,		2664,		2675,		2685,
-	2696,		2707,		2717,		2728,
-	2738,		2749,		2759,		2770,
-	2781,		2791,		2802,		2813,
-	2823,		2834,		2845,		2855,
-	2866,		2877,		2887,		2898,
-	2909,		2919,		2930,		2941,
-	2951,		2962,		2973,		2984,
-	2994,		3005,		3015,		3027,
-	3037,		3048,		3058,		3069,
-	3080,		3091,		3101,		3113,
-	3123,		3134,		3145,		3156,
-	3166,		3177,		3188,		3199,
-	3210,		3220,		3231,		3242,
-	3253,		3264,		3275,		3285,
-	3296,		3307,		3318,		3329,
-	3340,		3351,		3362,		3373,
-	3384,		3394,		3405,		3416,
-	3427,		3438,		3449,		3460,
-	3471,		3482,		3493,		3504,
-	3515,		3526,		3537,		3548,
-	3559,		3570,		3581,		3592,
-	3603,		3614,		3625,		3636,
-	3647,		3659,		3670,		3681,
-	3692,		3703,		3714,		3725,
-	3736,		3747,		3758,		3770,
-	3781,		3792,		3803,		3814,
-	3825,		3837,		3848,		3859,
-	3870,		3881,		3893,		3904,
-	3915,		3926,		3937,		3949,
-	3960,		3971,		3983,		3994,
-	4005,		4017,		4028,		4039,
-	4051,		4062,		4073,		4085,
-	4096,		4107,		4119,		4130,
-	4141,		4153,		4164,		4175,
-	4187,		4198,		4210,		4221,
-	4233,		4244,		4256,		4267,
-	4279,		4290,		4302,		4313,
-	4325,		4336,		4348,		4359,
-	4371,		4382,		4394,		4406,
-	4417,		4429,		4440,		4452,
-	4464,		4475,		4487,		4499,
-	4510,		4522,		4533,		4545,
-	4557,		4569,		4581,		4592,
-	4604,		4616,		4627,		4639,
-	4651,		4663,		4674,		4686,
-	4698,		4710,		4722,		4734,
-	4746,		4758,		4769,		4781,
-	4793,		4805,		4817,		4829,
-	4841,		4853,		4865,		4877,
-	4889,		4900,		4913,		4925,
-	4936,		4949,		4961,		4973,
-	4985,		4997,		5009,		5021,
-	5033,		5045,		5057,		5070,
-	5081,		5094,		5106,		5118,
-	5130,		5143,		5155,		5167,
-	5179,		5191,		5204,		5216,
-	5228,		5240,		5253,		5265,
-	5278,		5290,		5302,		5315,
-	5327,		5340,		5352,		5364,
-	5377,		5389,		5401,		5414,
-	5426,		5439,		5451,		5464,
-	5476,		5489,		5502,		5514,
-	5527,		5539,		5552,		5564,
-	5577,		5590,		5603,		5615,
-	5628,		5641,		5653,		5666,
-	5679,		5691,		5704,		5717,
-	5730,		5743,		5756,		5768,
-	5781,		5794,		5807,		5820,
-	5833,		5846,		5859,		5872,
-	5885,		5897,		5911,		5924,
-	5937,		5950,		5963,		5976,
-	5989,		6002,		6015,		6028,
-	6042,		6055,		6068,		6081,
-	6094,		6108,		6121,		6134,
-	6147,		6160,		6174,		6187,
-	6201,		6214,		6227,		6241,
-	6254,		6267,		6281,		6294,
-	6308,		6321,		6335,		6348,
-	6362,		6375,		6389,		6403,
-	6416,		6430,		6443,		6457,
-	6471,		6485,		6498,		6512,
-	6526,		6540,		6554,		6567,
-	6581,		6595,		6609,		6623,
-	6637,		6651,		6665,		6679,
-	6692,		6706,		6721,		6735,
-	6749,		6763,		6777,		6791,
-	6805,		6819,		6833,		6848,
-	6862,		6876,		6890,		6905,
-	6919,		6933,		6948,		6962,
-	6976,		6991,		7005,		7020,
-	7034,		7049,		7064,		7078,
-	7093,		7107,		7122,		7136,
-	7151,		7166,		7180,		7195,
-	7210,		7225,		7240,		7254,
-	7269,		7284,		7299,		7314,
-	7329,		7344,		7359,		7374,
-	7389,		7404,		7419,		7434,
-	7449,		7465,		7480,		7495,
-	7510,		7526,		7541,		7556,
-	7571,		7587,		7602,		7618,
-	7633,		7648,		7664,		7680,
-	7695,		7711,		7726,		7742,
-	7758,		7773,		7789,		7805,
-	7821,		7836,		7852,		7868,
-	7884,		7900,		7916,		7932,
-	7948,		7964,		7981,		7997,
-	8013,		8029,		8045,		8061,
-	8078,		8094,		8110,		8127,
-	8143,		8160,		8176,		8193,
-	8209,		8226,		8242,		8259,
-	8276,		8292,		8309,		8326,
-	8343,		8360,		8377,		8394,
-	8410,		8428,		8444,		8462,
-	8479,		8496,		8513,		8530,
-	8548,		8565,		8582,		8600,
-	8617,		8634,		8652,		8670,
-	8687,		8704,		8722,		8740,
-	8758,		8775,		8793,		8811,
-	8829,		8847,		8865,		8883,
-	8901,		8919,		8937,		8955,
-	8974,		8992,		9010,		9029,
-	9047,		9066,		9084,		9103,
-	9121,		9140,		9159,		9177,
-	9196,		9215,		9234,		9253,
-	9272,		9291,		9310,		9329,
-	9349,		9368,		9387,		9406,
-	9426,		9445,		9465,		9484,
-	9504,		9524,		9544,		9563,
-	9583,		9603,		9623,		9643,
-	9663,		9683,		9703,		9723,
-	9744,		9764,		9785,		9805,
-	9826,		9846,		9867,		9888,
-	9909,		9930,		9950,		9971,
-	9993,		10013,		10035,		10056,
-	10077,		10099,		10120,		10142,
-	10163,		10185,		10207,		10229,
-	10251,		10273,		10294,		10317,
-	10339,		10361,		10384,		10406,
-	10428,		10451,		10474,		10496,
-	10519,		10542,		10565,		10588,
-	10612,		10635,		10658,		10682,
-	10705,		10729,		10752,		10776,
-	10800,		10824,		10848,		10872,
-	10896,		10921,		10945,		10969,
-	10994,		11019,		11044,		11069,
-	11094,		11119,		11144,		11169,
-	11195,		11221,		11246,		11272,
-	11298,		11324,		11350,		11376,
-	11402,		11429,		11456,		11482,
-	11509,		11536,		11563,		11590,
-	11618,		11645,		11673,		11701,
-	11728,		11756,		11785,		11813,
-	11842,		11870,		11899,		11928,
-	11957,		11986,		12015,		12045,
-	12074,		12104,		12134,		12164,
-	12194,		12225,		12255,		12286,
-	12317,		12348,		12380,		12411,
-	12443,		12475,		12507,		12539,
-	12571,		12604,		12637,		12670,
-	12703,		12737,		12771,		12804,
-	12839,		12873,		12907,		12942,
-	12977,		13013,		13048,		13084,
-	13120,		13156,		13192,		13229,
-	13267,		13304,		13341,		13379,
-	13418,		13456,		13495,		13534,
-	13573,		13613,		13653,		13693,
-	13734,		13775,		13817,		13858,
-	13901,		13943,		13986,		14029,
-	14073,		14117,		14162,		14206,
-	14252,		14297,		14343,		14390,
-	14437,		14485,		14533,		14582,
-	14631,		14680,		14731,		14782,
-	14833,		14885,		14937,		14991,
-	15044,		15099,		15154,		15210,
-	15266,		15324,		15382,		15441,
-	15500,		15561,		15622,		15684,
-	15747,		15811,		15877,		15943,
-	16010,		16078,		16148,		16218,
-	16290,		16363,		16437,		16513,
-	16590,		16669,		16749,		16831,
-	16915,		17000,		17088,		17177,
-	17268,		17362,		17458,		17556,
-	17657,		17761,		17868,		17977,
-	18090,		18207,		18328,		18452,
-	18581,		18715,		18854,		18998,
-	19149,		19307,		19472,		19645,
-	19828,		20021,		20226,		20444,
-	20678,		20930,		21204,		21503,
-	21835,		22206,		22630,		23124,
-	23721,		24478,		25529,		27316,
-};
+static void init_crandom(struct crndstate *state, unsigned long rho)
+{
+	state->rho = rho;
+	state->last = net_random();
+}
+
+/* get_crandom - correlated random number generator
+ * Next number depends on last value.
+ * rho is scaled to avoid floating point.
+ */
+static unsigned long get_crandom(struct crndstate *state)
+{
+	u64 value, rho;
+	unsigned long answer;
+
+	if (state->rho == 0)	/* no correllation */
+		return net_random();
+
+	value = net_random();
+	rho = (u64)state->rho + 1;
+	answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
+	state->last = answer;
+	return answer;
+}
 
 /* tabledist - return a pseudo-randomly distributed value with mean mu and
  * std deviation sigma.  Uses table lookup to approximate the desired
  * distribution, and a uniformly-distributed pseudo-random source.
  */
-static inline int tabledist(int mu, int sigma)
+static unsigned long tabledist(int mu, int sigma, 
+			       struct crndstate *state,
+			       const struct disttable *dist)
 {
-	int x;
-	int index;
-	int sigmamod, sigmadiv;
+	int t, x, factor;
+	unsigned long rnd;
 
 	if (sigma == 0)
 		return mu;
 
-	index = (net_random() & (TABLESIZE-1));
-	sigmamod = sigma%TABLEFACTOR;
-	sigmadiv = sigma/TABLEFACTOR;
-	x = sigmamod*disttable[index];
+	rnd = get_crandom(state);
+
+	/* default uniform distribution */
+	if (dist == NULL) 
+		return (rnd % (2*sigma)) - sigma + mu;
 
+	factor = dist->factor;
+	t = dist->table[rnd % dist->size];
+
+	x = (sigma % factor) * t;
 	if (x >= 0)
-		x += TABLEFACTOR/2;
+		x += factor/2;
 	else
-		x -= TABLEFACTOR/2;
+		x -= factor/2;
 
-	x /= TABLEFACTOR;
-	x += sigmadiv*disttable[index];
-	x += mu;
-	return x;
+	return (x + (sigma / factor) * t) / factor + mu;
 }
 
-/* Enqueue packets with underlying discipline (fifo)
- * but mark them with current time first.
- */
-static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+/* Put skb in the private delayed queue. */
+static int delay_skb(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
 	struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
 	psched_time_t now;
-	long delay;
+	
+	PSCHED_GET_TIME(now);
+	PSCHED_TADD2(now, tabledist(q->latency, q->jitter, 
+				    &q->delay_cor, q->delay_dist),
+		     cb->time_to_send);
+	
+	/* Always queue at tail to keep packets in order */
+	if (likely(q->delayed.qlen < q->limit)) {
+		__skb_queue_tail(&q->delayed, skb);
+		sch->q.qlen++;
+		sch->stats.bytes += skb->len;
+		sch->stats.packets++;
+		return NET_XMIT_SUCCESS;
+	}
+
+	sch->stats.drops++;
+	kfree_skb(skb);
+	return NET_XMIT_DROP;
+}
+
+static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
 
 	pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
 
 	/* Random packet drop 0 => none, ~0 => all */
-	if (q->loss && q->loss >= net_random()) {
+	if (q->loss && q->loss >= get_crandom(&q->loss_cor)) {
+		pr_debug("netem_enqueue: random loss\n");
 		sch->stats.drops++;
 		return 0;	/* lie about loss so TCP doesn't know */
 	}
 
+	/* Random duplication */
+	if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) {
+		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
+		pr_debug("netem_enqueue: dup %p\n", skb2);
+		if (skb2)
+			delay_skb(sch, skb2);
+	}
 
 	/* If doing simple delay then gap == 0 so all packets
 	 * go into the delayed holding queue
@@ -634,26 +206,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 	
 	q->counter = 0;
 
-	PSCHED_GET_TIME(now);
-	if (q->jitter) 
-		delay = tabledist(q->latency, q->jitter);
-	else
-		delay = q->latency;
-
-	PSCHED_TADD2(now, delay, cb->time_to_send);
-	
-	/* Always queue at tail to keep packets in order */
-	if (likely(q->delayed.qlen < q->limit)) {
-		__skb_queue_tail(&q->delayed, skb);
-		sch->q.qlen++;
-		sch->stats.bytes += skb->len;
-		sch->stats.packets++;
-		return 0;
-	}
-
-	sch->stats.drops++;
-	kfree_skb(skb);
-	return NET_XMIT_DROP;
+	return delay_skb(sch, skb);
 }
 
 /* Requeue packets but don't change time stamp */
@@ -752,39 +305,94 @@ static int set_fifo_limit(struct Qdisc *q, int limit)
 	return ret;
 }
 
-static int netem_change(struct Qdisc *sch, struct rtattr *opt)
+static int get_dist_table(struct Qdisc *sch, const struct rtattr *attr)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
-	struct tc_netem_qopt *qopt = RTA_DATA(opt);
-	struct Qdisc *child;
-	int ret;
+	const struct tc_netem_dist *dist = RTA_DATA(attr);
+	struct disttable *d;
+	int i;
+
+	if (RTA_PAYLOAD(attr) < sizeof(*dist) ||
+	    dist->factor < 2 || dist->factor > 1<<16 || dist->size > 65536)
+		return -EINVAL;
+
+	d = kmalloc(sizeof(*d) + dist->size*sizeof(d->table[0]), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+
+	d->size = dist->size;
+	d->factor = dist->factor;
+	for (i = 0; i < dist->size; i++)
+		d->table[i] = dist->data[i];
+	
+	spin_lock_bh(&sch->dev->queue_lock);
+	d = xchg(&q->delay_dist, d);
+	spin_unlock_bh(&sch->dev->queue_lock);
+
+	kfree(d);
+	return 0;
+}
 
-	if (opt->rta_len < RTA_LENGTH(sizeof(*qopt)))
+static int get_correlation(struct Qdisc *sch, const struct rtattr *attr)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	const struct tc_netem_corr *c = RTA_DATA(attr);
+
+	if (RTA_PAYLOAD(attr) != sizeof(*c))
 		return -EINVAL;
 
-	child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops);
-	if (!child)
+	init_crandom(&q->delay_cor, c->delay_corr);
+	init_crandom(&q->loss_cor, c->loss_corr);
+	init_crandom(&q->dup_cor, c->dup_corr);
+	return 0;
+}
+
+static int netem_change(struct Qdisc *sch, struct rtattr *opt)
+{
+	struct netem_sched_data *q = qdisc_priv(sch);
+	struct tc_netem_qopt *qopt;
+	int ret;
+	
+	if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(*qopt))
 		return -EINVAL;
 
-	ret = set_fifo_limit(child, qopt->limit);
+	qopt = RTA_DATA(opt);
+	ret = set_fifo_limit(q->qdisc, qopt->limit);
 	if (ret) {
-		qdisc_destroy(child);
+		pr_debug("netem: can't set fifo limit\n");
 		return ret;
 	}
 	
-	sch_tree_lock(sch);
-	if (child) {
-		child = xchg(&q->qdisc, child);
-		if (child != &noop_qdisc)
-			qdisc_destroy(child);
-	
 	q->latency = qopt->latency;
 	q->jitter = qopt->jitter;
 	q->limit = qopt->limit;
 	q->gap = qopt->gap;
 	q->loss = qopt->loss;
+	q->duplicate = qopt->duplicate;
+
+	/* Handle nested options after initial queue options.
+	 * Should have put all options in nested format but too late now.
+	 */ 
+	if (RTA_PAYLOAD(opt) > sizeof(*qopt)) {
+		struct rtattr *tb[TCA_NETEM_MAX];
+		if (rtattr_parse(tb, TCA_NETEM_MAX, 
+				 RTA_DATA(opt) + sizeof(*qopt),
+				 RTA_PAYLOAD(opt) - sizeof(*qopt)))
+			return -EINVAL;
+
+		if (tb[TCA_NETEM_CORR-1]) {
+			ret = get_correlation(sch, tb[TCA_NETEM_CORR-1]);
+			if (ret)
+				return ret;
 		}
-	sch_tree_unlock(sch);
+
+		if (tb[TCA_NETEM_DELAY_DIST-1]) {
+			ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST-1]);
+			if (ret)
+				return ret;
+		}
+	}
+
 
 	return 0;
 }
@@ -792,19 +400,29 @@ static int netem_change(struct Qdisc *sch, struct rtattr *opt)
 static int netem_init(struct Qdisc *sch, struct rtattr *opt)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
+	int ret;
 
 	if (!opt)
 		return -EINVAL;
 
 	skb_queue_head_init(&q->delayed);
-	q->qdisc = &noop_qdisc;
-
 	init_timer(&q->timer);
 	q->timer.function = netem_watchdog;
 	q->timer.data = (unsigned long) sch;
 	q->counter = 0;
 
-	return netem_change(sch, opt);
+	q->qdisc = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops);
+	if (!q->qdisc) {
+		pr_debug("netem: qdisc create failed\n");
+		return -ENOMEM;
+	}
+
+	ret = netem_change(sch, opt);
+	if (ret) {
+		pr_debug("netem: change failed\n");
+		qdisc_destroy(q->qdisc);
+	}
+	return ret;
 }
 
 static void netem_destroy(struct Qdisc *sch)
@@ -817,18 +435,26 @@ static void netem_destroy(struct Qdisc *sch)
 
 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
-	struct netem_sched_data *q = qdisc_priv(sch);
+	const struct netem_sched_data *q = qdisc_priv(sch);
 	unsigned char	 *b = skb->tail;
+	struct rtattr *rta = (struct rtattr *) b;
 	struct tc_netem_qopt qopt;
+	struct tc_netem_corr cor;
 
 	qopt.latency = q->latency;
 	qopt.jitter = q->jitter;
 	qopt.limit = q->limit;
 	qopt.loss = q->loss;
 	qopt.gap = q->gap;
-
+	qopt.duplicate = q->duplicate;
 	RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
 
+	cor.delay_corr = q->delay_cor.rho;
+	cor.loss_corr = q->loss_cor.rho;
+	cor.dup_corr = q->dup_cor.rho;
+	RTA_PUT(skb, TCA_NETEM_CORR, sizeof(cor), &cor);
+	rta->rta_len = skb->tail - b;
+
 	return skb->len;
 
 rtattr_failure: