--- /dev/null
+/*
+ * $Id$
+ */
+
+/*
+ * 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)
+
+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;
+ char txcmd, rxcmd;
+ char txbuf[SLC_MTU];
+ char rxbuf[SLC_MTU];
+ int txp, rxp;
+ struct can_frame txf, rxf;
+ 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;
+
+ if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+ perror("bind");
+ return 1;
+ }
+
+ 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;
+ }
+
+ /* convert to struct can_frame rxf */
+ rxcmd = rxbuf[0];
+
+ if ((rxcmd != 't') && (rxcmd != 'T') &&
+ (rxcmd != 'r') && (rxcmd != 'R'))
+ continue;
+
+ 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')))
+ continue;
+
+ rxf.can_dlc = rxbuf[rxp] & 0x0F; /* get can_dlc */
+
+ if (rxf.can_dlc > 8)
+ continue;
+
+ 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)
+ continue;
+ rxf.data[i] = (tmp << 4);
+ tmp = asc2nibble(rxbuf[rxp++]);
+ if (tmp > 0x0F)
+ continue;
+ rxf.data[i] |= tmp;
+ }
+
+ nbytes = write(s, &rxf, sizeof(rxf));
+ if (nbytes != sizeof(rxf)) {
+ perror("write socket");
+ return 1;
+ }
+ }
+
+ 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]);
+
+ 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;
+}