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/*
* Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
*
* This file is subject to the terms and conditions of the GNU General Public
* License v2. See the file LICENSE for more details.
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <sys/select.h>
#include <sys/time.h>
#include <stdlib.h>
#include <netdb.h>
#include <termios.h>
#define MTU 9000
#define TRACE(x)
#define TTY_TIMEOUT_MS (500)
#define case_baudrate(val) \
case val: \
*baudrate = B ## val; \
break
#define BAUDRATE_DEFAULT B115200
#define TCP_DEV "tcp:"
#define IOTLAB_TCP_PORT "20000"
static void usage(void)
{
fprintf(stderr, "Usage: ethos <tap> <serial> [baudrate]\n");
fprintf(stderr, " ethos <tap> tcp:<host> [port]\n");
}
static void checked_write(int handle, void *buffer, int nbyte)
{
if (write(handle, buffer, nbyte) != nbyte) {
fprintf(stderr, "write to fd %i failed: %s\n", handle, strerror(errno));
}
}
int set_serial_attribs (int fd, int speed, int parity)
{
struct termios tty;
memset (&tty, 0, sizeof tty);
if (tcgetattr (fd, &tty) != 0)
{
perror ("error in tcgetattr");
return -1;
}
cfsetospeed (&tty, speed);
cfsetispeed (&tty, speed);
tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; /* 8-bit chars*/
/* disable IGNBRK for mismatched speed
* tests; otherwise receive break*/
/* as \000 chars*/
tty.c_iflag &= ~IGNBRK; /* disable break processing*/
tty.c_lflag = 0; /* no signaling chars, no echo,*/
/* no canonical processing*/
tty.c_oflag = 0; /* no remapping, no delays*/
tty.c_cc[VMIN] = 0; /* read doesn't block*/
tty.c_cc[VTIME] = TTY_TIMEOUT_MS / 100; /* 0.5 seconds read timeout*/
/* in tenths of a second*/
tty.c_iflag &= ~(IXON | IXOFF | IXANY); /* shut off xon/xoff ctrl*/
tty.c_cflag |= (CLOCAL | CREAD); /* ignore modem controls,*/
/* enable reading*/
tty.c_cflag &= ~(PARENB | PARODD); /* shut off parity*/
tty.c_cflag |= parity;
tty.c_cflag &= ~CSTOPB;
tty.c_cflag &= ~CRTSCTS;
cfmakeraw(&tty);
if (tcsetattr (fd, TCSANOW, &tty) != 0)
{
perror("error from tcsetattr");
return -1;
}
return 0;
}
void set_blocking (int fd, int should_block)
{
struct termios tty;
memset (&tty, 0, sizeof tty);
if (tcgetattr (fd, &tty) != 0)
{
perror("error from tggetattr");
return;
}
tty.c_cc[VMIN] = should_block ? 1 : 0;
tty.c_cc[VTIME] = TTY_TIMEOUT_MS / 100; /* 0.5 seconds read timeout*/
/* in tenths of a second*/
if (tcsetattr (fd, TCSANOW, &tty) != 0)
perror("error setting term attributes");
}
/**
* @brief Escape char definitions
* @{
*/
#define LINE_FRAME_DELIMITER (0x7E)
#define LINE_ESC_CHAR (0x7D)
#define LINE_FRAME_TYPE_DATA (0x00)
#define LINE_FRAME_TYPE_TEXT (0x01)
#define LINE_FRAME_TYPE_HELLO (0x02)
#define LINE_FRAME_TYPE_HELLO_REPLY (0x03)
/** @} */
typedef enum {
WAIT_FRAMESTART,
IN_FRAME,
IN_ESCAPE
} line_state_t;
typedef struct {
line_state_t state;
int frametype;
size_t framebytes;
char frame[MTU];
char local_l2_addr[6];
char remote_l2_addr[6];
} serial_t;
/**************************************************************************
* tun_alloc: allocates or reconnects to a tun/tap device. The caller *
* needs to reserve enough space in *dev. *
**************************************************************************/
int tun_alloc(char *dev, int flags) {
struct ifreq ifr;
int fd, err;
if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
perror("Opening /dev/net/tun");
return fd;
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = flags;
if (*dev) {
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
}
if( (err = ioctl(fd, TUNSETIFF, (void *)&ifr)) < 0 ) {
perror("ioctl(TUNSETIFF)");
close(fd);
return err;
}
strcpy(dev, ifr.ifr_name);
return fd;
}
static void _handle_char(serial_t *serial, char c)
{
serial->frame[serial->framebytes] = c;
serial->framebytes++;
}
static int _serial_handle_byte(serial_t *serial, char c)
{
switch (serial->state) {
case WAIT_FRAMESTART:
if (c == LINE_FRAME_DELIMITER) {
TRACE("frame start");
serial->state = IN_FRAME;
serial->frametype = 0;
serial->framebytes = 0;
}
break;
case IN_FRAME:
if (c == LINE_ESC_CHAR) {
TRACE("i esc");
serial->state = IN_ESCAPE;
}
else if (c == LINE_FRAME_DELIMITER) {
if (!serial->framebytes) {
TRACE("i del unexp");
} else {
TRACE("i del");
serial->state = WAIT_FRAMESTART;
return serial->framebytes;
}
}
else {
_handle_char(serial, c);
}
break;
case IN_ESCAPE:
if (c == (LINE_FRAME_DELIMITER ^ 0x20)) {
_handle_char(serial, LINE_FRAME_DELIMITER);
}
else if (c == (LINE_ESC_CHAR ^ 0x20)) {
_handle_char(serial, LINE_ESC_CHAR);
}
else if (c == (LINE_FRAME_TYPE_TEXT ^ 0x20)) {
TRACE("esc txt");
serial->frametype = LINE_FRAME_TYPE_TEXT;
}
else if (c == (LINE_FRAME_TYPE_HELLO ^ 0x20)) {
TRACE("esc hello");
serial->frametype = LINE_FRAME_TYPE_HELLO;
}
else if (c == (LINE_FRAME_TYPE_HELLO_REPLY ^ 0x20)) {
TRACE("esc hello_reply");
serial->frametype = LINE_FRAME_TYPE_HELLO_REPLY;
}
else if (c == LINE_FRAME_DELIMITER) {
TRACE("esc -del");
}
serial->state = IN_FRAME;
break;
}
return 0;
}
static void _write_escaped(int fd, char* buf, ssize_t n)
{
uint8_t out[2];
size_t escaped = 0;
while(n--) {
char c = *buf++;
switch(c) {
case LINE_FRAME_DELIMITER:
out[0] = LINE_ESC_CHAR;
out[1] = (LINE_FRAME_DELIMITER ^ 0x20);
checked_write(fd, out, 2);
escaped++;
break;
case LINE_ESC_CHAR:
out[0] = LINE_ESC_CHAR;
out[1] = (LINE_ESC_CHAR ^ 0x20);
checked_write(fd, out, 2);
escaped++;
break;
default:
checked_write(fd, &c, 1);
}
}
}
static void _send_hello(int serial_fd, serial_t *serial, unsigned type)
{
char delim = LINE_FRAME_DELIMITER;
char head[] = { LINE_FRAME_DELIMITER, LINE_ESC_CHAR, (type ^ 0x20) };
checked_write(serial_fd, head, sizeof(head));
checked_write(serial_fd, serial->local_l2_addr, 6);
checked_write(serial_fd, &delim, 1);
}
static void _clear_neighbor_cache(const char *ifname)
{
char tmp[20 + IFNAMSIZ];
snprintf(tmp, sizeof(tmp), "ip neigh flush dev %s", ifname);
if (system(tmp) < 0) {
fprintf(stderr, "error while flushing device neighbor cache\n");
}
}
static int _parse_baudrate(const char *arg, unsigned *baudrate)
{
if (arg == NULL) {
*baudrate = BAUDRATE_DEFAULT;
return 0;
}
switch(strtol(arg, (char**)NULL, 10)) {
case 9600:
*baudrate = B9600;
break;
case 19200:
*baudrate = B19200;
break;
case 38400:
*baudrate = B38400;
break;
case 57600:
*baudrate = B57600;
break;
case 115200:
*baudrate = B115200;
break;
/* the following baudrates might not be available on all platforms */
#ifdef B234000
case_baudrate(230400);
#endif
#ifdef B460800
case_baudrate(460800);
#endif
#ifdef B500000
case_baudrate(500000);
#endif
#ifdef B576000
case_baudrate(576000);
#endif
#ifdef B921600
case_baudrate(921600);
#endif
#ifdef B1000000
case_baudrate(1000000);
#endif
#ifdef B1152000
case_baudrate(1152000);
#endif
#ifdef B1500000
case_baudrate(1500000);
#endif
#ifdef B2000000
case_baudrate(2000000);
#endif
#ifdef B2500000
case_baudrate(2500000);
#endif
#ifdef B3000000
case_baudrate(3000000);
#endif
#ifdef B3500000
case_baudrate(3500000);
#endif
#ifdef B4000000
case_baudrate(4000000);
#endif
default:
return -1;
}
return 0;
}
int _parse_tcp_arg(char *name, char *port_arg, char **host, char **port)
{
/* Remove 'tcp:' */
name = &name[sizeof(TCP_DEV) - 1];
/* Set default if NULL */
if (!port_arg) {
port_arg = IOTLAB_TCP_PORT;
}
*host = name;
*port = port_arg;
return 0;
}
/* Adapted from 'getaddrinfo' manpage example */
int _tcp_connect(char *host, char *port)
{
int sfd = -1;
struct addrinfo hints, *result, *rp;
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
int s = getaddrinfo(host, port, &hints, &result);
if (s) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
return -1;
}
/* getaddrinfo() returns a list of address structures.
Try each address until we successfully connect(2).
If socket(2) (or connect(2)) fails, we (close the socket
and) try the next address. */
for (rp = result; rp != NULL; rp = rp->ai_next) {
sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sfd == -1)
continue;
if (connect(sfd, rp->ai_addr, rp->ai_addrlen) != -1)
break;
close(sfd);
}
freeaddrinfo(result);
if (rp == NULL) {
fprintf(stderr, "Could not connect to '%s:%s'\n", host, port);
return -1;
}
return sfd;
}
int _set_socket_timeout(int sfd)
{
struct timeval timeout = {
.tv_sec = 0,
.tv_usec = TTY_TIMEOUT_MS * 1000,
};
if (setsockopt(sfd, SOL_SOCKET, SO_RCVTIMEO,
(char *)&timeout, sizeof(timeout)) == -1) {
perror("setsockopt failed\n");
return 1;
}
if (setsockopt(sfd, SOL_SOCKET, SO_SNDTIMEO,
(char *)&timeout, sizeof(timeout)) == -1) {
perror("setsockopt failed\n");
return 1;
}
return 0;
}
int _open_tcp_connection(char *name, char *port_arg)
{
char *host;
char *port;
int ret = _parse_tcp_arg(name, port_arg, &host, &port);
if (ret) {
fprintf(stderr, "Error while parsing tcp arguments\n");
return -1;
}
int sfd = _tcp_connect(host, port);
if (_set_socket_timeout(sfd)) {
fprintf(stderr, "Error while setting socket options\n");
return -1;
}
return sfd;
}
int _open_serial_connection(char *name, char *baudrate_arg)
{
unsigned baudrate = 0;
if (_parse_baudrate(baudrate_arg, &baudrate) == -1) {
fprintf(stderr, "Invalid baudrate specified: %s\n", baudrate_arg);
return 1;
}
int serial_fd = open(name, O_RDWR | O_NOCTTY | O_SYNC);
if (serial_fd < 0) {
fprintf(stderr, "Error opening serial device %s\n", name);
return -1;
}
set_serial_attribs(serial_fd, baudrate, 0);
set_blocking(serial_fd, 1);
return serial_fd;
}
int _open_connection(char *name, char* option)
{
if (strncmp(name, TCP_DEV, strlen(TCP_DEV)) == 0) {
return _open_tcp_connection(name, option);
} else {
return _open_serial_connection(name, option);
}
}
int main(int argc, char *argv[])
{
char inbuf[MTU];
char *serial_option = NULL;
serial_t serial = {0};
if (argc < 3) {
usage();
return 1;
}
if (argc >= 4) {
serial_option = argv[3];
}
char ifname[IFNAMSIZ];
strncpy(ifname, argv[1], IFNAMSIZ);
int tap_fd = tun_alloc(ifname, IFF_TAP | IFF_NO_PI);
if (tap_fd < 0) {
return 1;
}
int serial_fd = _open_connection(argv[2], serial_option);
if (serial_fd < 0) {
fprintf(stderr, "Error opening serial device %s\n", argv[2]);
return 1;
}
fd_set readfds;
int max_fd = (serial_fd > tap_fd) ? serial_fd : tap_fd;
fprintf(stderr, "----> ethos: sending hello.\n");
_send_hello(serial_fd, &serial, LINE_FRAME_TYPE_HELLO);
fprintf(stderr, "----> ethos: activating serial pass through.\n");
_send_hello(serial_fd, &serial, LINE_FRAME_TYPE_HELLO);
while(1) {
int activity;
FD_ZERO(&readfds);
FD_SET(STDIN_FILENO, &readfds);
FD_SET(tap_fd, &readfds);
FD_SET(serial_fd, &readfds);
activity = select( max_fd + 1 , &readfds , NULL , NULL , NULL);
if ((activity < 0) && (errno != EINTR))
{
perror("select error");
}
if (FD_ISSET(serial_fd, &readfds)) {
ssize_t n = read(serial_fd, inbuf, sizeof(inbuf));
if (n > 0) {
char *ptr = inbuf;
while (n--) {
size_t res = _serial_handle_byte(&serial, *ptr++);
if (res) {
switch (serial.frametype) {
case LINE_FRAME_TYPE_DATA:
checked_write(tap_fd, serial.frame, serial.framebytes);
break;
case LINE_FRAME_TYPE_TEXT:
checked_write(STDOUT_FILENO, serial.frame, serial.framebytes);
break;
case LINE_FRAME_TYPE_HELLO:
case LINE_FRAME_TYPE_HELLO_REPLY:
if (serial.framebytes == 6) {
memcpy(serial.remote_l2_addr, serial.frame, 6);
if (serial.frametype == LINE_FRAME_TYPE_HELLO) {
fprintf(stderr, "----> ethos: hello received\n");
_send_hello(serial_fd, &serial, LINE_FRAME_TYPE_HELLO_REPLY);
} else {
fprintf(stderr, "----> ethos: hello reply received\n");
}
_clear_neighbor_cache(ifname);
}
break;
}
memset(&serial, '\0', sizeof(serial));
}
}
}
else {
fprintf(stderr, "lost serial connection.\n");
exit(1);
}
}
if (FD_ISSET(tap_fd, &readfds)) {
ssize_t res = read(tap_fd, inbuf, sizeof(inbuf));
if (res <= 0) {
fprintf(stderr, "error reading from tap device. res=%zi\n", res);
continue;
}
char delim = LINE_FRAME_DELIMITER;
checked_write(serial_fd, &delim, 1);
_write_escaped(serial_fd, inbuf, res);
checked_write(serial_fd, &delim, 1);
}
if (FD_ISSET(STDIN_FILENO, &readfds)) {
ssize_t res = read(STDIN_FILENO, inbuf, sizeof(inbuf));
if (res <= 0) {
fprintf(stderr, "error reading from stdio. res=%zi\n", res);
continue;
}
if (res) {
char delim = LINE_FRAME_DELIMITER;
char head[] = { LINE_FRAME_DELIMITER, LINE_ESC_CHAR, (LINE_FRAME_TYPE_TEXT ^ 0x20) };
checked_write(serial_fd, head, sizeof(head));
_write_escaped(serial_fd, inbuf, res);
checked_write(serial_fd, &delim, 1);
}
}
}
return 0;
}