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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 <getopt.h>
#include <stdbool.h>
#include <signal.h>
#include <err.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(bool error)
{
fprintf(error ? stderr : stdout,
"Usage:\n"
"\tlatency <latency> <rate> [--client <ip>] [OPTION]...\n"
"or\n"
"\tlatency --server [OPTION]...\n"
"\n"
"Options:\n"
" -h, --help Show this help\n"
" --port <PORT> Specify port to use (default 61234)\n"
" --cap-file <FN> Specify a capture file\n"
" --framing-bytes <BYTES> Specify physical framing bytes\n"
);
exit(error ? EXIT_FAILURE : EXIT_SUCCESS);
}
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 },
{ "g", 1000000000 },
{ "G", 1024 * 1024 * 1024 },
{ "kbit", 1000. / 8. },
{ "Kbit", 1024. / 8. },
{ "mbit", 1000000. / 8. },
{ "Mbit", 1024. * 1024. / 8. },
{ "gbit", 1000000000. / 8. },
{ "Gbit", 1024. * 1024. * 1024./ 8. },
{ "", 1 },
{ NULL, 0 }
};
static const unit no_units[] = {
{ "", 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);
if (setuid(0))
err(EXIT_FAILURE, "setuid");
}
enum { MODE_local, MODE_server, MODE_client } mode = MODE_local;
enum { ARG_port = 256, ARG_client, ARG_server, ARG_capfile,
ARG_framingbytes };
static struct option long_options[] = {
{"client", required_argument, 0, ARG_client },
{"server", no_argument, 0, ARG_server },
{"port", required_argument, 0, ARG_port },
{"cap-file",required_argument, 0, ARG_capfile },
{"framing-bytes",required_argument, 0, ARG_framingbytes },
{"help", no_argument, 0, 'h' },
{0, 0, 0, 0 }
};
const char *str_port = "61234";
const char *client_dest = NULL;
int ch;
while ((ch = getopt_long(argc, argv, "h", long_options, NULL)) != -1) {
switch (ch) {
case 'h':
usage(false);
case ARG_client:
if (mode == MODE_server)
usage(true);
mode = MODE_client;
client_dest = optarg;
break;
case ARG_server:
if (mode == MODE_client)
usage(true);
mode = MODE_server;
break;
case ARG_port:
str_port = optarg;
break;
case ARG_capfile:
tun_log_filename = optarg;
break;
case ARG_framingbytes:
framing_bytes = parse_value(optarg, 0, 1000, no_units);
break;
default:
usage(true);
}
}
tun_setup(mode == MODE_local);
if (ruid != euid) {
if (setuid(ruid))
err(EXIT_FAILURE, "setuid");
}
int port = parse_value(str_port, 1, 65535, no_units);
if (mode != MODE_server) {
if (optind + 2 > argc)
usage(true);
latency_us = parse_value(argv[optind], 0, 10000000, latency_units);
rate_bytes = parse_value(argv[optind+1], 1, INT_MAX, rate_units);
if (mode == MODE_client)
tun_set_client(client_dest, port);
} else {
latency_us = 0;
rate_bytes = 100000000;
tun_set_server(port);
}
setup_signals();
handle_tun();
return EXIT_SUCCESS;
}
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