1 /* 2 * tc_core.c TC core library. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet (at) ms2.inr.ac.ru> 10 * 11 */ 12 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <unistd.h> 16 #include <syslog.h> 17 #include <fcntl.h> 18 #include <math.h> 19 #include <sys/socket.h> 20 #include <netinet/in.h> 21 #include <arpa/inet.h> 22 #include <string.h> 23 24 #include "tc_core.h" 25 #include <linux/atm.h> 26 27 static double tick_in_usec = 1; 28 static double clock_factor = 1; 29 30 int tc_core_time2big(unsigned time) 31 { 32 __u64 t = time; 33 34 t *= tick_in_usec; 35 return (t >> 32) != 0; 36 } 37 38 39 unsigned tc_core_time2tick(unsigned time) 40 { 41 return time*tick_in_usec; 42 } 43 44 unsigned tc_core_tick2time(unsigned tick) 45 { 46 return tick/tick_in_usec; 47 } 48 49 unsigned tc_core_time2ktime(unsigned time) 50 { 51 return time * clock_factor; 52 } 53 54 unsigned tc_core_ktime2time(unsigned ktime) 55 { 56 return ktime / clock_factor; 57 } 58 59 unsigned tc_calc_xmittime(unsigned rate, unsigned size) 60 { 61 return tc_core_time2tick(TIME_UNITS_PER_SEC*((double)size/rate)); 62 } 63 64 unsigned tc_calc_xmitsize(unsigned rate, unsigned ticks) 65 { 66 return ((double)rate*tc_core_tick2time(ticks))/TIME_UNITS_PER_SEC; 67 } 68 69 /* 70 * The align to ATM cells is used for determining the (ATM) SAR 71 * alignment overhead at the ATM layer. (SAR = Segmentation And 72 * Reassembly). This is for example needed when scheduling packet on 73 * an ADSL connection. Note that the extra ATM-AAL overhead is _not_ 74 * included in this calculation. This overhead is added in the kernel 75 * before doing the rate table lookup, as this gives better precision 76 * (as the table will always be aligned for 48 bytes). 77 * --Hawk, d.7/11-2004. <hawk (at) diku.dk> 78 */ 79 unsigned tc_align_to_atm(unsigned size) 80 { 81 int linksize, cells; 82 cells = size / ATM_CELL_PAYLOAD; 83 if ((size % ATM_CELL_PAYLOAD) > 0) 84 cells++; 85 86 linksize = cells * ATM_CELL_SIZE; /* Use full cell size to add ATM tax */ 87 return linksize; 88 } 89 90 unsigned tc_adjust_size(unsigned sz, unsigned mpu, enum link_layer linklayer) 91 { 92 if (sz < mpu) 93 sz = mpu; 94 95 switch (linklayer) { 96 case LINKLAYER_ATM: 97 return tc_align_to_atm(sz); 98 case LINKLAYER_ETHERNET: 99 default: 100 // No size adjustments on Ethernet 101 return sz; 102 } 103 } 104 105 /* 106 rtab[pkt_len>>cell_log] = pkt_xmit_time 107 */ 108 109 int tc_calc_rtable(struct tc_ratespec *r, __u32 *rtab, 110 int cell_log, unsigned mtu, 111 enum link_layer linklayer) 112 { 113 int i; 114 unsigned sz; 115 unsigned bps = r->rate; 116 unsigned mpu = r->mpu; 117 118 if (mtu == 0) 119 mtu = 2047; 120 121 if (cell_log < 0) { 122 cell_log = 0; 123 while ((mtu >> cell_log) > 255) 124 cell_log++; 125 } 126 127 for (i=0; i<256; i++) { 128 sz = tc_adjust_size((i + 1) << cell_log, mpu, linklayer); 129 rtab[i] = tc_calc_xmittime(bps, sz); 130 } 131 132 r->cell_align=-1; // Due to the sz calc 133 r->cell_log=cell_log; 134 return cell_log; 135 } 136 137 /* 138 stab[pkt_len>>cell_log] = pkt_xmit_size>>size_log 139 */ 140 141 int tc_calc_size_table(struct tc_sizespec *s, __u16 **stab) 142 { 143 int i; 144 enum link_layer linklayer = s->linklayer; 145 unsigned int sz; 146 147 if (linklayer <= LINKLAYER_ETHERNET && s->mpu == 0) { 148 /* don't need data table in this case (only overhead set) */ 149 s->mtu = 0; 150 s->tsize = 0; 151 s->cell_log = 0; 152 s->cell_align = 0; 153 *stab = NULL; 154 return 0; 155 } 156 157 if (s->mtu == 0) 158 s->mtu = 2047; 159 if (s->tsize == 0) 160 s->tsize = 512; 161 162 s->cell_log = 0; 163 while ((s->mtu >> s->cell_log) > s->tsize - 1) 164 s->cell_log++; 165 166 *stab = malloc(s->tsize * sizeof(__u16)); 167 if (!*stab) 168 return -1; 169 170 again: 171 for (i = s->tsize - 1; i >= 0; i--) { 172 sz = tc_adjust_size((i + 1) << s->cell_log, s->mpu, linklayer); 173 if ((sz >> s->size_log) > UINT16_MAX) { 174 s->size_log++; 175 goto again; 176 } 177 (*stab)[i] = sz >> s->size_log; 178 } 179 180 s->cell_align = -1; // Due to the sz calc 181 return 0; 182 } 183 184 int tc_core_init() 185 { 186 FILE *fp; 187 __u32 clock_res; 188 __u32 t2us; 189 __u32 us2t; 190 191 fp = fopen("/proc/net/psched", "r"); 192 if (fp == NULL) 193 return -1; 194 195 if (fscanf(fp, "%08x%08x%08x", &t2us, &us2t, &clock_res) != 3) { 196 fclose(fp); 197 return -1; 198 } 199 fclose(fp); 200 201 /* compatibility hack: for old iproute binaries (ignoring 202 * the kernel clock resolution) the kernel advertises a 203 * tick multiplier of 1000 in case of nano-second resolution, 204 * which really is 1. */ 205 if (clock_res == 1000000000) 206 t2us = us2t; 207 208 clock_factor = (double)clock_res / TIME_UNITS_PER_SEC; 209 tick_in_usec = (double)t2us / us2t * clock_factor; 210 return 0; 211 } 212
