Systemd/src/network/tc/tc-util.c
2019-12-10 01:28:38 +09:00

95 lines
2.3 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+
* Copyright © 2019 VMware, Inc. */
#include "alloc-util.h"
#include "fileio.h"
#include "parse-util.h"
#include "tc-util.h"
#include "time-util.h"
static int tc_init(double *ticks_in_usec) {
uint32_t clock_resolution, ticks_to_usec, usec_to_ticks;
_cleanup_free_ char *line = NULL;
double clock_factor;
int r;
r = read_one_line_file("/proc/net/psched", &line);
if (r < 0)
return r;
r = sscanf(line, "%08x%08x%08x", &ticks_to_usec, &usec_to_ticks, &clock_resolution);
if (r < 3)
return -EIO;
clock_factor = (double) clock_resolution / USEC_PER_SEC;
*ticks_in_usec = (double) ticks_to_usec / usec_to_ticks * clock_factor;
return 0;
}
int tc_time_to_tick(usec_t t, uint32_t *ret) {
static double ticks_in_usec = -1;
usec_t a;
int r;
assert(ret);
if (ticks_in_usec < 0) {
r = tc_init(&ticks_in_usec);
if (r < 0)
return r;
}
a = t * ticks_in_usec;
if (a > UINT32_MAX)
return -ERANGE;
*ret = a;
return 0;
}
int parse_tc_percent(const char *s, uint32_t *percent) {
int r;
assert(s);
assert(percent);
r = parse_permille(s);
if (r < 0)
return r;
*percent = (double) r / 1000 * UINT32_MAX;
return 0;
}
int tc_transmit_time(uint64_t rate, uint32_t size, uint32_t *ret) {
return tc_time_to_tick(USEC_PER_SEC * ((double)size / (double)rate), ret);
}
int tc_fill_ratespec_and_table(struct tc_ratespec *rate, uint32_t *rtab, uint32_t mtu) {
uint32_t cell_log = 0;
int r;
if (mtu == 0)
mtu = 2047;
while ((mtu >> cell_log) > 255)
cell_log++;
for (size_t i = 0; i < 256; i++) {
uint32_t sz;
sz = (i + 1) << cell_log;
if (sz < rate->mpu)
sz = rate->mpu;
r = tc_transmit_time(rate->rate, sz, &rtab[i]);
if (r < 0)
return r;
}
rate->cell_align = -1;
rate->cell_log = cell_log;
rate->linklayer = TC_LINKLAYER_ETHERNET;
return 0;
}