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can-utils/slcanpty.c

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/*
* $Id$
*/
/*
* slcanpty.c - creates a pty for applications using the slcan ASCII protocol
* and converts the ASCII data to a CAN network interface (and vice versa)
*
* Copyright (c)2009 Oliver Hartkopp
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Send feedback to <socketcan-users@lists.berlios.de>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <linux/can.h>
#include <linux/can/raw.h>
/* maximum rx buffer len: extended CAN frame with timestamp */
#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
#define DEBUG
static int asc2nibble(char c)
{
if ((c >= '0') && (c <= '9'))
return c - '0';
if ((c >= 'A') && (c <= 'F'))
return c - 'A' + 10;
if ((c >= 'a') && (c <= 'f'))
return c - 'a' + 10;
return 16; /* error */
}
int main(int argc, char **argv)
{
fd_set rdfs;
int p; /* pty master file */
int s; /* can raw socket */
int nbytes;
struct sockaddr_can addr;
struct termios topts;
struct ifreq ifr;
int running = 1;
int tstamp = 0;
int is_open = 0;
char txcmd, rxcmd;
char txbuf[SLC_MTU];
char rxbuf[200];
char replybuf[SLC_MTU];
int txp, rxp;
struct can_frame txf, rxf;
struct can_filter fi;
int tmp, i;
/* check command line options */
if (argc != 3) {
fprintf(stderr, "\n");
fprintf(stderr, "%s creates a pty for applications using"
" the slcan ASCII protocol and\n", argv[0]);
fprintf(stderr, "converts the ASCII data to a CAN network"
" interface (and vice versa)\n\n");
fprintf(stderr, "Usage: %s <pty> <can interface>\n", argv[0]);
fprintf(stderr, "e.g. '%s /dev/ptyc0 can0' creates"
" /dev/ttyc0 for the slcan application\n", argv[0]);
fprintf(stderr, "\n");
return 1;
}
/* open pty */
p = open(argv[1], O_RDWR);
if (p < 0) {
perror("open pty");
return 1;
}
if (tcgetattr(p, &topts)) {
perror("tcgetattr");
return 1;
}
/* disable local echo which would cause double frames */
topts.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK |
ECHONL | ECHOPRT | ECHOKE | ICRNL);
tcsetattr(p, TCSANOW, &topts);
/* open socket */
s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
if (s < 0) {
perror("socket");
return 1;
}
addr.can_family = AF_CAN;
strcpy(ifr.ifr_name, argv[2]);
if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
addr.can_ifindex = ifr.ifr_ifindex;
/* disable reception of CAN frames until we are opened by 'O' */
setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0);
if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("bind");
return 1;
}
/* open filter by default */
fi.can_id = 0;
fi.can_mask = 0;
while (running) {
FD_ZERO(&rdfs);
FD_SET(0, &rdfs);
FD_SET(p, &rdfs);
FD_SET(s, &rdfs);
if (select(s+1, &rdfs, NULL, NULL, NULL) < 0) {
perror("select");
return 1;
}
if (FD_ISSET(0, &rdfs)) {
running = 0;
continue;
}
if (FD_ISSET(p, &rdfs)) {
/* read rxdata from pty */
nbytes = read(p, &rxbuf, sizeof(rxbuf)-1);
if (nbytes < 0) {
perror("read pty");
return 1;
}
rx_restart:
/* remove trailing '\r' characters */
while (rxbuf[0] == '\r' && nbytes > 0) {
for (tmp = 0; tmp < nbytes; tmp++)
rxbuf[tmp] = rxbuf[tmp+1];
nbytes--;
}
if (nbytes < 2)
continue;
rxcmd = rxbuf[0];
#ifdef DEBUG
for (tmp = 0; tmp < nbytes; tmp++)
if (rxbuf[tmp] == '\r')
putchar('@');
else
putchar(rxbuf[tmp]);
printf("\n");
#endif
/* check for filter configuration commands */
if (rxcmd == 'm' || rxcmd == 'M') {
rxbuf[9] = 0; /* terminate filter string */
rxp = 9;
#if 0
/* the filter is no SocketCAN filter :-( */
/* TODO: behave like a SJA1000 filter */
if (rxcmd == 'm') {
fi.can_id = strtoul(rxbuf+1,NULL,16);
fi.can_id &= CAN_EFF_MASK;
} else {
fi.can_mask = strtoul(rxbuf+1,NULL,16);
fi.can_mask &= CAN_EFF_MASK;
}
/* set only when both values are defined */
if (is_open)
setsockopt(s, SOL_CAN_RAW,
CAN_RAW_FILTER, &fi,
sizeof(struct can_filter));
#endif
goto rx_out_ack;
}
/* check for timestamp on/off command */
if (rxcmd == 'Z') {
tstamp = rxbuf[1] & 0x01;
rxp = 2;
goto rx_out_ack;
}
/* check for 'O'pen command */
if (rxcmd == 'O') {
setsockopt(s, SOL_CAN_RAW,
CAN_RAW_FILTER, &fi,
sizeof(struct can_filter));
rxp = 1;
is_open = 1;
goto rx_out_ack;
}
/* check for 'C'lose command */
if (rxcmd == 'C') {
setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER,
NULL, 0);
rxp = 1;
is_open = 0;
goto rx_out_ack;
}
/* check for 'V'ersion command */
if (rxcmd == 'V') {
sprintf(replybuf, "V1013\r");
tmp = strlen(replybuf);
rxp = 1;
goto rx_out;
}
/* check for serial 'N'umber command */
if (rxcmd == 'N') {
sprintf(replybuf, "N4242\r");
tmp = strlen(replybuf);
rxp = 1;
goto rx_out;
}
/* check for read status 'F'lags */
if (rxcmd == 'F') {
sprintf(replybuf, "F00\r");
tmp = strlen(replybuf);
rxp = 1;
goto rx_out;
}
/* correctly answer unsupported commands */
if (rxcmd == 'U') {
rxp = 2;
goto rx_out_ack;
}
if (rxcmd == 'S') {
rxp = 2;
goto rx_out_ack;
}
if (rxcmd == 's') {
rxp = 5;
goto rx_out_ack;
}
if (rxcmd == 'P' || rxcmd == 'A') {
rxp = 1;
goto rx_out_nack;
}
if (rxcmd == 'X') {
rxp = 2;
if (rxbuf[1] & 0x01)
goto rx_out_ack;
else
goto rx_out_nack;
}
/* catch unknown commands */
if ((rxcmd != 't') && (rxcmd != 'T') &&
(rxcmd != 'r') && (rxcmd != 'R')) {
rxp = nbytes-1;
goto rx_out_nack;
}
if (rxcmd & 0x20) /* tiny chars 'r' 't' => SFF */
rxp = 4; /* dlc position tiiid */
else
rxp = 9; /* dlc position Tiiiiiiiid */
if (!((rxbuf[rxp] >= '0') && (rxbuf[rxp] < '9')))
goto rx_out_nack;
rxf.can_dlc = rxbuf[rxp] & 0x0F; /* get can_dlc */
rxbuf[rxp] = 0; /* terminate can_id string */
rxf.can_id = strtoul(rxbuf+1, NULL, 16);
if (!(rxcmd & 0x20)) /* NO tiny chars => EFF */
rxf.can_id |= CAN_EFF_FLAG;
if ((rxcmd | 0x20) == 'r') /* RTR frame */
rxf.can_id |= CAN_RTR_FLAG;
*(unsigned long long *) (&rxf.data) = 0ULL; /* clear */
for (i = 0, rxp++; i < rxf.can_dlc; i++) {
tmp = asc2nibble(rxbuf[rxp++]);
if (tmp > 0x0F)
goto rx_out_nack;
rxf.data[i] = (tmp << 4);
tmp = asc2nibble(rxbuf[rxp++]);
if (tmp > 0x0F)
goto rx_out_nack;
rxf.data[i] |= tmp;
}
/* point to last real data */
if (rxf.can_dlc)
rxp--;
nbytes = write(s, &rxf, sizeof(rxf));
if (nbytes != sizeof(rxf)) {
perror("write socket");
return 1;
}
rx_out_ack:
replybuf[0] = '\r';
tmp = 1;
goto rx_out;
rx_out_nack:
replybuf[0] = '\a';
tmp = 1;
rx_out:
tmp = write(p, replybuf, tmp);
if (tmp < 0) {
perror("write pty replybuf");
return 1;
}
/* check if there is another command in this buffer */
if (nbytes > rxp+1) {
for (tmp = 0, rxp++; rxp+tmp < nbytes; tmp++)
rxbuf[tmp] = rxbuf[rxp+tmp];
nbytes = tmp;
goto rx_restart;
}
}
if (FD_ISSET(s, &rdfs)) {
/* read txframe from CAN interface */
nbytes = read(s, &txf, sizeof(txf));
if (nbytes != sizeof(txf)) {
perror("read socket");
return 1;
}
/* convert to slcan ASCII txf */
if (txf.can_id & CAN_RTR_FLAG)
txcmd = 'R'; /* becomes 'r' in SFF format */
else
txcmd = 'T'; /* becomes 't' in SFF format */
if (txf.can_id & CAN_EFF_FLAG)
sprintf(txbuf, "%c%08X%d", txcmd,
txf.can_id & CAN_EFF_MASK,
txf.can_dlc);
else
sprintf(txbuf, "%c%03X%d", txcmd | 0x20,
txf.can_id & CAN_SFF_MASK,
txf.can_dlc);
txp = strlen(txbuf);
for (i = 0; i < txf.can_dlc; i++)
sprintf(&txbuf[txp + 2*i], "%02X",
txf.data[i]);
if (tstamp) {
struct timeval tv;
if (ioctl(s, SIOCGSTAMP, &tv) < 0)
perror("SIOCGSTAMP");
sprintf(&txbuf[txp + 2*txf.can_dlc], "%04lX",
(tv.tv_sec%60)*1000 + tv.tv_usec/1000);
}
strcat(txbuf, "\r"); /* add terminating character */
nbytes = write(p, txbuf, strlen(txbuf));
if (nbytes < 0) {
perror("write pty");
return 1;
}
fflush(NULL);
}
}
close(p);
close(s);
return 0;
}
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