--- /dev/null
+/*
+ * net/sched/sch_netem.c Network emulator
+ *
+ * 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: Stephen Hemminger <shemminger@osdl.org>
+ * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <asm/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+
+#include <net/pkt_sched.h>
+
+/* Network emulator
+ *
+ * This scheduler can alters spacing and order
+ * Similar to NISTnet and BSD Dummynet.
+ */
+
+struct netem_sched_data {
+ struct Qdisc *qdisc;
+ struct sk_buff_head delayed;
+ struct timer_list timer;
+
+ u32 latency;
+ u32 loss;
+ u32 limit;
+ u32 counter;
+ u32 gap;
+ u32 jitter;
+};
+
+/* Time stamp put into socket buffer control block */
+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.
+ */
+#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,
+};
+
+/* 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)
+{
+ int x;
+ int index;
+ int sigmamod, sigmadiv;
+
+ if (sigma == 0)
+ return mu;
+
+ index = (net_random() & (TABLESIZE-1));
+ sigmamod = sigma%TABLEFACTOR;
+ sigmadiv = sigma/TABLEFACTOR;
+ x = sigmamod*disttable[index];
+
+ if (x >= 0)
+ x += TABLEFACTOR/2;
+ else
+ x -= TABLEFACTOR/2;
+
+ x /= TABLEFACTOR;
+ x += sigmadiv*disttable[index];
+ x += mu;
+ return x;
+}
+
+/* Enqueue packets with underlying discipline (fifo)
+ * but mark them with current time first.
+ */
+static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb;
+ psched_time_t now;
+ long delay;
+
+ pr_debug("netem_enqueue skb=%p @%lu\n", skb, jiffies);
+
+ /* Random packet drop 0 => none, ~0 => all */
+ if (q->loss && q->loss >= net_random()) {
+ sch->stats.drops++;
+ return 0; /* lie about loss so TCP doesn't know */
+ }
+
+
+ /* If doing simple delay then gap == 0 so all packets
+ * go into the delayed holding queue
+ * otherwise if doing out of order only "1 out of gap"
+ * packets will be delayed.
+ */
+ if (q->counter < q->gap) {
+ int ret;
+
+ ++q->counter;
+ ret = q->qdisc->enqueue(skb, q->qdisc);
+ if (ret)
+ sch->stats.drops++;
+ return ret;
+ }
+
+ 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 */
+ __skb_queue_tail(&q->delayed, skb);
+ sch->q.qlen++;
+ sch->stats.bytes += skb->len;
+ sch->stats.packets++;
+ return 0;
+}
+
+/* Requeue packets but don't change time stamp */
+static int netem_requeue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ int ret;
+
+ if ((ret = q->qdisc->ops->requeue(skb, q->qdisc)) == 0)
+ sch->q.qlen++;
+
+ return ret;
+}
+
+static unsigned int netem_drop(struct Qdisc* sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ unsigned int len;
+
+ if ((len = q->qdisc->ops->drop(q->qdisc)) != 0) {
+ sch->q.qlen--;
+ sch->stats.drops++;
+ }
+ return len;
+}
+
+/* Dequeue packet.
+ * Move all packets that are ready to send from the delay holding
+ * list to the underlying qdisc, then just call dequeue
+ */
+static struct sk_buff *netem_dequeue(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ struct sk_buff *skb;
+ psched_time_t now;
+
+ PSCHED_GET_TIME(now);
+ while ((skb = skb_peek(&q->delayed)) != NULL) {
+ const struct netem_skb_cb *cb
+ = (const struct netem_skb_cb *)skb->cb;
+ long delay
+ = PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now));
+ pr_debug("netem_dequeue: delay queue %p@%lu %ld\n",
+ skb, jiffies, delay);
+
+ /* if more time remaining? */
+ if (delay > 0) {
+ mod_timer(&q->timer, jiffies + delay);
+ break;
+ }
+ __skb_unlink(skb, &q->delayed);
+
+ if (q->qdisc->enqueue(skb, q->qdisc))
+ sch->stats.drops++;
+ }
+
+ skb = q->qdisc->dequeue(q->qdisc);
+ if (skb)
+ sch->q.qlen--;
+ return skb;
+}
+
+static void netem_watchdog(unsigned long arg)
+{
+ struct Qdisc *sch = (struct Qdisc *)arg;
+
+ pr_debug("netem_watchdog: fired @%lu\n", jiffies);
+ netif_schedule(sch->dev);
+}
+
+static void netem_reset(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ qdisc_reset(q->qdisc);
+ skb_queue_purge(&q->delayed);
+
+ sch->q.qlen = 0;
+ del_timer_sync(&q->timer);
+}
+
+static int set_fifo_limit(struct Qdisc *q, int limit)
+{
+ struct rtattr *rta;
+ int ret = -ENOMEM;
+
+ rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
+ if (rta) {
+ rta->rta_type = RTM_NEWQDISC;
+ rta->rta_len = RTA_LENGTH(sizeof(struct tc_fifo_qopt));
+ ((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit;
+
+ ret = q->ops->change(q, rta);
+ kfree(rta);
+ }
+ return ret;
+}
+
+static int netem_change(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ struct tc_netem_qopt *qopt = RTA_DATA(opt);
+ struct Qdisc *child;
+ int ret;
+
+ if (opt->rta_len < RTA_LENGTH(sizeof(*qopt)))
+ return -EINVAL;
+
+ child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops);
+ if (!child)
+ return -EINVAL;
+
+ ret = set_fifo_limit(child, qopt->limit);
+ if (ret) {
+ qdisc_destroy(child);
+ 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;
+ }
+ sch_tree_unlock(sch);
+
+ return 0;
+}
+
+static int netem_init(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ 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);
+}
+
+static void netem_destroy(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+
+ del_timer_sync(&q->timer);
+}
+
+static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct netem_sched_data *q = (struct netem_sched_data *)sch->data;
+ unsigned char *b = skb->tail;
+ struct tc_netem_qopt qopt;
+
+ qopt.latency = q->latency;
+ qopt.jitter = q->jitter;
+ qopt.limit = sch->dev->tx_queue_len;
+ qopt.loss = q->loss;
+ qopt.gap = q->gap;
+
+ RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
+
+ return skb->len;
+
+rtattr_failure:
+ skb_trim(skb, b - skb->data);
+ return -1;
+}
+
+static struct Qdisc_ops netem_qdisc_ops = {
+ .id = "netem",
+ .priv_size = sizeof(struct netem_sched_data),
+ .enqueue = netem_enqueue,
+ .dequeue = netem_dequeue,
+ .requeue = netem_requeue,
+ .drop = netem_drop,
+ .init = netem_init,
+ .reset = netem_reset,
+ .destroy = netem_destroy,
+ .change = netem_change,
+ .dump = netem_dump,
+ .owner = THIS_MODULE,
+};
+
+
+static int __init netem_module_init(void)
+{
+ return register_qdisc(&netem_qdisc_ops);
+}
+static void __exit netem_module_exit(void)
+{
+ unregister_qdisc(&netem_qdisc_ops);
+}
+module_init(netem_module_init)
+module_exit(netem_module_exit)
+MODULE_LICENSE("GPL");
git://git.onelab.eu / linux-2.6.git / blobdiff