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/*
* tc_core.c TC core library.
*
* 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: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <fcntl.h>
#include <math.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include "tc_core.h"
#include <linux/atm.h>
static double tick_in_usec = 1;
static double clock_factor = 1;
int tc_core_time2big(unsigned time)
{
__u64 t = time;
t *= tick_in_usec;
return (t >> 32) != 0;
}
unsigned tc_core_time2tick(unsigned time)
{
return time*tick_in_usec;
}
unsigned tc_core_tick2time(unsigned tick)
{
return tick/tick_in_usec;
}
unsigned tc_core_time2ktime(unsigned time)
{
return time * clock_factor;
}
unsigned tc_core_ktime2time(unsigned ktime)
{
return ktime / clock_factor;
}
unsigned tc_calc_xmittime(unsigned rate, unsigned size)
{
return tc_core_time2tick(TIME_UNITS_PER_SEC*((double)size/rate));
}
unsigned tc_calc_xmitsize(unsigned rate, unsigned ticks)
{
return ((double)rate*tc_core_tick2time(ticks))/TIME_UNITS_PER_SEC;
}
/*
* The align to ATM cells is used for determining the (ATM) SAR
* alignment overhead at the ATM layer. (SAR = Segmentation And
* Reassembly). This is for example needed when scheduling packet on
* an ADSL connection. Note that the extra ATM-AAL overhead is _not_
* included in this calculation. This overhead is added in the kernel
* before doing the rate table lookup, as this gives better precision
* (as the table will always be aligned for 48 bytes).
* --Hawk, d.7/11-2004. <hawk@diku.dk>
*/
unsigned tc_align_to_atm(unsigned size)
{
int linksize, cells;
cells = size / ATM_CELL_PAYLOAD;
if ((size % ATM_CELL_PAYLOAD) > 0)
cells++;
linksize = cells * ATM_CELL_SIZE; /* Use full cell size to add ATM tax */
return linksize;
}
unsigned tc_adjust_size(unsigned sz, unsigned mpu, enum link_layer linklayer)
{
if (sz < mpu)
sz = mpu;
switch (linklayer) {
case LINKLAYER_ATM:
return tc_align_to_atm(sz);
case LINKLAYER_ETHERNET:
default:
// No size adjustments on Ethernet
return sz;
}
}
/*
rtab[pkt_len>>cell_log] = pkt_xmit_time
*/
int tc_calc_rtable(struct tc_ratespec *r, __u32 *rtab,
int cell_log, unsigned mtu,
enum link_layer linklayer)
{
int i;
unsigned sz;
unsigned bps = r->rate;
unsigned mpu = r->mpu;
if (mtu == 0)
mtu = 2047;
if (cell_log < 0) {
cell_log = 0;
while ((mtu >> cell_log) > 255)
cell_log++;
}
for (i=0; i<256; i++) {
sz = tc_adjust_size((i + 1) << cell_log, mpu, linklayer);
rtab[i] = tc_calc_xmittime(bps, sz);
}
r->cell_align=-1; // Due to the sz calc
r->cell_log=cell_log;
return cell_log;
}
/*
stab[pkt_len>>cell_log] = pkt_xmit_size>>size_log
*/
int tc_calc_size_table(struct tc_sizespec *s, __u16 **stab)
{
int i;
enum link_layer linklayer = s->linklayer;
unsigned int sz;
if (linklayer <= LINKLAYER_ETHERNET && s->mpu == 0) {
/* don't need data table in this case (only overhead set) */
s->mtu = 0;
s->tsize = 0;
s->cell_log = 0;
s->cell_align = 0;
*stab = NULL;
return 0;
}
if (s->mtu == 0)
s->mtu = 2047;
if (s->tsize == 0)
s->tsize = 512;
s->cell_log = 0;
while ((s->mtu >> s->cell_log) > s->tsize - 1)
s->cell_log++;
*stab = malloc(s->tsize * sizeof(__u16));
if (!*stab)
return -1;
again:
for (i = s->tsize - 1; i >= 0; i--) {
sz = tc_adjust_size((i + 1) << s->cell_log, s->mpu, linklayer);
if ((sz >> s->size_log) > UINT16_MAX) {
s->size_log++;
goto again;
}
(*stab)[i] = sz >> s->size_log;
}
s->cell_align = -1; // Due to the sz calc
return 0;
}
int tc_core_init()
{
FILE *fp;
__u32 clock_res;
__u32 t2us;
__u32 us2t;
fp = fopen("/proc/net/psched", "r");
if (fp == NULL)
return -1;
if (fscanf(fp, "%08x%08x%08x", &t2us, &us2t, &clock_res) != 3) {
fclose(fp);
return -1;
}
fclose(fp);
/* compatibility hack: for old iproute binaries (ignoring
* the kernel clock resolution) the kernel advertises a
* tick multiplier of 1000 in case of nano-second resolution,
* which really is 1. */
if (clock_res == 1000000000)
t2us = us2t;
clock_factor = (double)clock_res / TIME_UNITS_PER_SEC;
tick_in_usec = (double)t2us / us2t * clock_factor;
return 0;
}
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