tc/tc_core.c

   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@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
  26 static __u32 t2us=1;
  27 static __u32 us2t=1;
  28 static double tick_in_usec = 1;
  29
  30 long tc_core_usec2tick(long usec)
  31 {
  32         return usec*tick_in_usec;
  33 }
  34
  35 long tc_core_tick2usec(long tick)
  36 {
  37         return tick/tick_in_usec;
  38 }
  39
  40 unsigned tc_calc_xmittime(unsigned rate, unsigned size)
  41 {
  42         return tc_core_usec2tick(1000000*((double)size/rate));
  43 }
  44
  45 /*
  46    rtab[pkt_len>>cell_log] = pkt_xmit_time
  47  */
  48
  49 int tc_calc_rtable(unsigned bps, __u32 *rtab, int cell_log, unsigned mtu,
  50                    unsigned mpu)
  51 {
  52         int i;
  53
  54         if (mtu == 0)
  55                 mtu = 2047;
  56
  57         if (cell_log < 0) {
  58                 cell_log = 0;
  59                 while ((mtu>>cell_log) > 255)
  60                         cell_log++;
  61         }
  62         for (i=0; i<256; i++) {
  63                 unsigned sz = (i<<cell_log);
  64                 if (sz < mpu)
  65                         sz = mpu;
  66                 rtab[i] = tc_core_usec2tick(1000000*((double)sz/bps));
  67         }
  68         return cell_log;
  69 }
  70
  71 int tc_core_init()
  72 {
  73         FILE *fp = fopen("/proc/net/psched", "r");
  74
  75         if (fp == NULL)
  76                 return -1;
  77
  78         if (fscanf(fp, "%08x%08x", &t2us, &us2t) != 2) {
  79                 fclose(fp);
  80                 return -1;
  81         }
  82         fclose(fp);
  83         tick_in_usec = (double)t2us/us2t;
  84         return 0;
  85 }