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/* Attempt to reduce bandwidth of a given connection
*
* args:
* - listening port;
* - connection port;
* - latency (ms);
* - bandwidth kbits (send/receive or receive);
* - bandwidth kbits (send).
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include "latency.h"
#include "tun.h"
#include "utils.h"
volatile int term = 0;
static void
sig_term(int sig)
{
term = 1;
}
static void
sig_chld(int sig)
{
int status;
while (waitpid(-1, &status, WNOHANG) > 0)
continue;
}
static void
setup_signals(void)
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = sig_term;
sigaction(SIGTERM, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
signal(SIGCHLD, sig_chld);
}
uint64_t latency_us;
unsigned rate_bytes;
static void
usage(void)
{
fprintf(stderr, "syntax: latency <latency> <rate>\n");
exit(EXIT_FAILURE);
}
static const unit latency_units[] = {
{ "ms", 1000 },
{ "s", 1000000 },
{ "", 1000 },
{ NULL, 0 }
};
static const unit rate_units[] = {
{ "k", 1000 },
{ "K", 1024 },
{ "m", 1000000 },
{ "M", 1024 * 1024 },
{ "kbit", 1000. / 8. },
{ "Kbit", 1024. / 8. },
{ "mbit", 1000000. / 8. },
{ "Mbit", 1024. * 1024. / 8. },
{ "", 1 },
{ NULL, 0 }
};
/**/
int
main(int argc, char **argv)
{
uid_t ruid = getuid(), euid = geteuid();
if (ruid != euid && euid == 0) {
clearenv();
setenv("HOME", "/root", 1);
setenv("PATH", "/sbin:/bin:/usr/sbin:/usr/bin", 1);
setenv("SHELL", "/bin/sh", 1);
setuid(0);
}
tun_setup();
if (ruid != euid)
setuid(ruid);
if (argc < 3)
usage();
latency_us = parse_value(argv[1], 0, 10000000, latency_units);
rate_bytes = parse_value(argv[2], 1, INT_MAX, rate_units);
setup_signals();
handle_tun();
return EXIT_SUCCESS;
}
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