543 lines
12 KiB
C
543 lines
12 KiB
C
#include "common.h"
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#include "buffer.h"
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#include "db.h"
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#include "ip.h"
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#include "option.h"
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#include "state.h"
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#include "str.h"
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#include "tun.h"
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#include <fcntl.h>
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#include <inttypes.h>
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#include <limits.h>
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#include <poll.h>
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#include <signal.h>
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#include <stdio.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include "mud.h"
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#ifndef O_CLOEXEC
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#define O_CLOEXEC 0
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#endif
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static struct {
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volatile sig_atomic_t quit;
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volatile sig_atomic_t info;
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int timeout;
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int state_fd;
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} gt;
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static void
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fd_set_nonblock(int fd)
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{
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int ret;
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do {
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ret = fcntl(fd, F_GETFL, 0);
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} while (ret == -1 && errno == EINTR);
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int flags = (ret == -1) ? 0 : ret;
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do {
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ret = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
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} while (ret == -1 && errno == EINTR);
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if (ret == -1)
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perror("fcntl O_NONBLOCK");
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}
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static void
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gt_sa_handler(int sig)
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{
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switch (sig) {
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case SIGINT:
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case SIGQUIT:
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case SIGTERM:
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gt.quit = 1;
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break;
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case SIGUSR1:
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gt.info = 1;
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break;
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}
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}
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static void
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gt_set_signal(void)
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{
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struct sigaction sa = {
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.sa_flags = 0,
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};
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sigemptyset(&sa.sa_mask);
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sa.sa_handler = gt_sa_handler;
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sigaction(SIGINT, &sa, NULL);
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sigaction(SIGQUIT, &sa, NULL);
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sigaction(SIGTERM, &sa, NULL);
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sigaction(SIGUSR1, &sa, NULL);
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sa.sa_handler = SIG_IGN;
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sigaction(SIGHUP, &sa, NULL);
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sigaction(SIGPIPE, &sa, NULL);
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}
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static ssize_t
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fd_read(int fd, void *data, size_t size)
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{
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if ((fd == -1) || !size)
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return -1;
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ssize_t ret = read(fd, data, size);
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if (ret == -1) {
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if (errno == EAGAIN || errno == EINTR)
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return -1;
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if (errno)
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perror("read");
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return 0;
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}
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return ret;
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}
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static ssize_t
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fd_write(int fd, const void *data, size_t size)
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{
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if ((fd == -1) || !size)
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return -1;
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ssize_t ret = write(fd, data, size);
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if (ret == -1) {
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if (errno == EAGAIN || errno == EINTR)
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return -1;
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if (errno == EPIPE || errno == ECONNRESET)
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return 0;
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if (errno)
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perror("write");
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return 0;
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}
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return ret;
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}
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static size_t
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fd_read_all(int fd, void *data, size_t size)
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{
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size_t done = 0;
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while (done < size) {
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ssize_t ret = fd_read(fd, (uint8_t *)data + done, size - done);
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if (!ret)
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break;
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if (ret < 0) {
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struct pollfd pollfd = {
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.fd = fd,
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.events = POLLIN,
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};
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if (!poll(&pollfd, 1, gt.timeout))
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break;
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continue;
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}
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done += ret;
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}
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return done;
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}
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static size_t
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fd_write_all(int fd, const void *data, size_t size)
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{
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size_t done = 0;
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while (done < size) {
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ssize_t ret = fd_write(fd, (const uint8_t *)data + done, size - done);
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if (!ret)
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break;
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if (ret < 0) {
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struct pollfd pollfd = {
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.fd = fd,
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.events = POLLOUT,
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};
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if (!poll(&pollfd, 1, gt.timeout))
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break;
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continue;
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}
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done += ret;
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}
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return done;
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}
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static int
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gt_setup_secretkey(struct mud *mud, char *keyfile)
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{
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unsigned char key[32];
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if (str_empty(keyfile)) {
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char buf[2 * sizeof(key) + 1];
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size_t size = sizeof(key);
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if (mud_get_key(mud, key, &size))
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return -1;
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gt_tohex(buf, sizeof(buf), key, size);
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state_send(gt.state_fd, "SECRETKEY", buf);
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return 0;
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}
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int fd;
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do {
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fd = open(keyfile, O_RDONLY | O_CLOEXEC);
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} while (fd == -1 && errno == EINTR);
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if (fd == -1) {
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perror("open keyfile");
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return -1;
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}
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char buf[2 * sizeof(key)];
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size_t r = fd_read_all(fd, buf, sizeof(buf));
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close(fd);
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if (r != sizeof(buf)) {
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gt_log("unable to read secret key\n");
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return -1;
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}
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if (gt_fromhex(key, sizeof(key), buf, sizeof(buf))) {
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gt_log("secret key is not valid\n");
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return -1;
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}
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mud_set_key(mud, key, sizeof(key));
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return 0;
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}
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int
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main(int argc, char **argv)
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{
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gt_set_signal();
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char *host = NULL;
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long port = 5000;
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char *bind_list = NULL;
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char *bind_backup = NULL;
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long bind_port = 5000;
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char *dev = NULL;
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char *keyfile = NULL;
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char *statefile = NULL;
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long mtu = 1450;
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gt.timeout = 5000;
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long time_tolerance = 0;
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int v4 = 1;
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int v6 = 0;
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#ifdef __linux__
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v6 = 1;
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#endif
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struct option opts[] = {
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// clang-format off
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{ "host", &host, option_str },
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{ "port", &port, option_long },
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{ "bind", &bind_list, option_str },
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{ "bind-backup", &bind_backup, option_str },
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{ "bind-port", &bind_port, option_long },
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{ "dev", &dev, option_str },
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{ "mtu", &mtu, option_long },
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{ "keyfile", &keyfile, option_str },
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{ "statefile", &statefile, option_str },
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{ "timeout", >.timeout, option_long },
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{ "time-tolerance", &time_tolerance, option_long },
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{ "v4only", NULL, option_option },
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{ "v6only", NULL, option_option },
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{ "chacha20", NULL, option_option },
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{ "version", NULL, option_option },
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{ NULL },
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// clang-format on
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};
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if (option(opts, argc, argv))
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return 1;
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if (option_is_set(opts, "version")) {
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gt_print(PACKAGE_STRING "\n");
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return 0;
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}
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if (option_is_set(opts, "v4only")) {
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v4 = 1;
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v6 = 0;
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}
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if (option_is_set(opts, "v6only")) {
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v4 = 0;
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v6 = 1;
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}
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if (option_is_set(opts, "v4only") &&
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option_is_set(opts, "v6only")) {
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gt_log("v4only and v6only are both set\n");
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return 1;
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}
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if (host && !option_is_set(opts, "keyfile")) {
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gt_log("keyfile option must be set\n");
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return 1;
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}
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if (gt.timeout <= 0 || gt.timeout > INT_MAX) {
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gt_log("bad timeout\n");
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return 1;
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}
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int icmp_fd = -1;
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if (v4) {
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icmp_fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
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if (icmp_fd == -1)
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gt_log("couldn't create ICMP socket\n");
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}
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gt.state_fd = state_create(statefile);
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if (statefile && gt.state_fd == -1)
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return 1;
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char *tun_name = NULL;
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int tun_fd = tun_create(dev, &tun_name);
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if (tun_fd == -1) {
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gt_log("couldn't create tun device\n");
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return 1;
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}
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if (tun_set_mtu(tun_name, mtu) == -1) {
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perror("tun_set_mtu");
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return 1;
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}
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fd_set_nonblock(tun_fd);
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int chacha = option_is_set(opts, "chacha20");
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struct mud *mud = mud_create(bind_port, v4, v6, !chacha, mtu);
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if (!mud) {
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gt_log("couldn't create mud\n");
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return 1;
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}
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if (gt_setup_secretkey(mud, keyfile))
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return 1;
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mud_set_send_timeout_msec(mud, gt.timeout);
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if (time_tolerance > 0)
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mud_set_time_tolerance_sec(mud, time_tolerance);
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if (host && port) {
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if (bind_backup) {
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if (mud_peer(mud, bind_backup, host, port, 1)) {
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perror("mud_peer (backup)");
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return 1;
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}
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}
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if (bind_list) {
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char tmp[1024];
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char *name = &tmp[0];
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str_cpy(tmp, bind_list, sizeof(tmp) - 1);
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while (*name) {
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char *p = name;
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while (*p && *p != ',')
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p++;
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if (*p)
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*p++ = 0;
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if (mud_peer(mud, name, host, port, 0)) {
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perror("mud_peer");
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return 1;
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}
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name = p;
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}
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}
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}
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int mud_fd = mud_get_fd(mud);
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fd_set_nonblock(mud_fd);
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state_send(gt.state_fd, "INITIALIZED", tun_name);
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fd_set rfds;
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FD_ZERO(&rfds);
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unsigned char buf[8 * 1024];
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while (!gt.quit) {
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FD_SET(tun_fd, &rfds);
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FD_SET(mud_fd, &rfds);
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if (icmp_fd != -1)
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FD_SET(icmp_fd, &rfds);
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if (select(mud_fd + 1, &rfds, NULL, NULL, NULL) == -1) {
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if (errno == EINTR)
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continue;
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perror("select");
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return 1;
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}
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if (icmp_fd != -1 && FD_ISSET(icmp_fd, &rfds)) {
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struct sockaddr_storage ss;
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socklen_t sl = sizeof(ss);
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ssize_t r = recvfrom(icmp_fd, buf, sizeof(buf), 0,
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(struct sockaddr *)&ss, &sl);
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if (r >= 8) {
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struct ip_common ic;
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if (!ip_get_common(&ic, buf, r) && ic.proto == 1) {
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unsigned char *data = &buf[ic.hdr_size];
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if (data[0] == 3) {
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int new_mtu = (data[6] << 8) | data[7];
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if (new_mtu) {
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gt_log("received MTU from ICMP: %i\n", new_mtu);
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mud_set_mtu(mud, new_mtu - 50); // XXX
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}
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}
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}
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}
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}
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if (FD_ISSET(tun_fd, &rfds)) {
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size_t size = 0;
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while (sizeof(buf) - size > mtu) {
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const ssize_t r = tun_read(tun_fd, &buf[size],
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sizeof(buf) - size);
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if (r <= 0)
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break;
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struct ip_common ic;
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if (ip_get_common(&ic, &buf[size], r) || ic.size != r)
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break;
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size += r;
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}
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int p = 0;
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while (p < size) {
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int tc = 0;
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int q = p;
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while (q < size) {
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struct ip_common ic;
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if ((ip_get_common(&ic, &buf[q], size - q)) ||
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(ic.size > size - q)) {
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size = q;
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break;
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}
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if (q + ic.size > p + mtu)
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break;
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q += ic.size;
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if (tc < (ic.tc & 0xFC))
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tc = ic.tc & 0xFC;
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}
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int r = mud_send(mud, &buf[p], q - p, tc);
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if (r == -1 && errno == EMSGSIZE) {
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int new_mtu = mud_get_mtu(mud);
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if (new_mtu != mtu) {
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mtu = new_mtu;
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gt_log("MTU changed: %li\n", mtu);
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if (tun_set_mtu(tun_name, mtu) == -1)
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perror("tun_set_mtu");
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}
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} else {
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if (r == -1 && errno != EAGAIN)
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perror("mud_send");
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p = q;
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}
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}
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}
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if (FD_ISSET(mud_fd, &rfds)) {
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while (1) {
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const int size = mud_recv(mud, buf, sizeof(buf));
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if (size <= 0) {
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if (size == -1 && errno != EAGAIN)
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perror("mud_recv");
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break;
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}
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int p = 0;
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while (p < size) {
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struct ip_common ic;
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if ((ip_get_common(&ic, &buf[p], size - p)) ||
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(ic.size > size - p))
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break;
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tun_write(tun_fd, &buf[p], ic.size);
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p += ic.size;
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}
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}
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}
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}
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return 0;
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}
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