text: /*
   *  $Id$
   */
  
  /*
   * isotpserver.c
   *
   * Implements a socket server which understands ASCII HEX
   * messages for simple TCP/IP <-> ISO 15765-2 bridging.
   *
   * General message format: <[data]+>
   *
   * e.g. for an eight bytes PDU
   *
   * <1122334455667788>
   *
   * Valid ISO 15625-2 PDUs have a length from 1-4095 bytes.
   *
   * Authors:
   * Andre Naujoks (the socket server stuff)
   * Oliver Hartkopp (the rest)
   *
   * Copyright (c) 2002-2010 Volkswagen Group Electronic Research
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of Volkswagen nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * Alternatively, provided that this notice is retained in full, this
   * software may be distributed under the terms of the GNU General
   * Public License ("GPL") version 2, in which case the provisions of the
   * GPL apply INSTEAD OF those given above.
   *
   * The provided data structures and external interfaces from this code
   * are not restricted to be used by modules with a GPL compatible license.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   * Send feedback to <linux-can@vger.kernel.org>
   *
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <libgen.h>
  #include <unistd.h>
  #include <string.h>
  #include <signal.h>
  #include <errno.h>
  
  #include <sys/types.h>
  #include <sys/wait.h>
  #include <sys/socket.h>
  #include <sys/ioctl.h>
  #include <sys/uio.h>
  #include <net/if.h>
  #include <netinet/in.h>
  
  #include <linux/can.h>
  #include <linux/can/isotp.h>
  
  #define NO_CAN_ID 0xFFFFFFFFU
  
  int b64hex(char *asc, unsigned char *bin, int len)
  {
  	int i;
  
  	for (i = 0; i < len; i++) {
  		if (!sscanf(asc+(i*2), "%2hhx", bin+i))
  			return 1;	
  	}
  	return 0;
  }
  
  void childdied(int i)
  {
  	wait(NULL);
  }
  
  void print_usage(char *prg)
  {
  	fprintf(stderr, "\nUsage: %s -l <port> -s <can_id> -d <can_id> [options] <CAN interface>\n", prg);
  	fprintf(stderr, "Options: (* = mandatory)\n");
  	fprintf(stderr, "\n");
  	fprintf(stderr, "ip adressing:\n");
  	fprintf(stderr, " *       -l <port>    (local port for the server)\n");
  	fprintf(stderr, "\n");
  	fprintf(stderr, "isotp adressing:\n");
  	fprintf(stderr, " *       -s <can_id>  (source can_id. Use 8 digits for extended IDs)\n");
  	fprintf(stderr, " *       -d <can_id>  (destination can_id. Use 8 digits for extended IDs)\n");
  	fprintf(stderr, "         -x <addr>    (extended addressing mode)\n");
  	fprintf(stderr, "\n");
  	fprintf(stderr, "padding:\n");
  	fprintf(stderr, "         -p <byte>    (set and enable tx padding byte)\n");
  	fprintf(stderr, "         -r <byte>    (set and enable rx padding byte)\n");
  	fprintf(stderr, "         -P <mode>    (check padding in SF/CF. (l)ength (c)ontent (a)ll)\n");
  	fprintf(stderr, "\n");
  	fprintf(stderr, "rx path: (config, which is sent to the sender / data source)\n");
  	fprintf(stderr, "         -b <bs>      (blocksize. 0 = off)\n");
  	fprintf(stderr, "         -m <val>     (STmin in ms/ns. See spec.)\n");
  	fprintf(stderr, "         -w <num>     (max. wait frame transmissions)\n");
  	fprintf(stderr, "\n");
  	fprintf(stderr, "tx path: (config, which changes local tx settings)\n");
  	fprintf(stderr, "         -t <time ns> (transmit time in nanosecs)\n");
  	fprintf(stderr, "\n");
  	fprintf(stderr, "All values except for '-l' and '-t' are expected in hexadecimal values.\n");
  	fprintf(stderr, "\n");
  }
  
  int main(int argc, char **argv)
  {
  	extern int optind, opterr, optopt;
  	int opt;
  
  	int sl, sa, sc; /* (L)isten, (A)ccept, (C)AN sockets */ 
  	struct sockaddr_in  saddr, clientaddr;
  	struct sockaddr_can caddr;
  	static struct can_isotp_options opts;
  	static struct can_isotp_fc_options fcopts;
  	struct ifreq ifr;
  	socklen_t sin_size = sizeof(clientaddr);
  	socklen_t caddrlen = sizeof(caddr);
  
  	struct sigaction signalaction;
  	sigset_t sigset;
  
  	fd_set readfds;
  
  	int i, ret;
  	int nbytes;
  
  	int local_port = 0;
  	int verbose = 0;
  
  	int idx = 0; /* index in txmsg[] */
  
  	unsigned char msg[4096];   /* isotp socket message buffer (4095 + test_for_too_long_byte)*/
  	char rxmsg[8194]; /* isotp->tcp ASCII message buffer (4095*2 + < > \n null) */
  	char txmsg[8193]; /* tcp->isotp ASCII message buffer (4095*2 + < > null) */
  
  	/* mark missing mandatory commandline options as missing */
  	caddr.can_addr.tp.tx_id = caddr.can_addr.tp.rx_id = NO_CAN_ID;
  
  	while ((opt = getopt(argc, argv, "l:s:d:x:p:r:P:b:m:w:t:v?")) != -1) {
  		switch (opt) {
  		case 'l':
  			local_port = strtoul(optarg, (char **)NULL, 10);
  			break;
  
  		case 's':
  			caddr.can_addr.tp.tx_id = strtoul(optarg, (char **)NULL, 16);
  			if (strlen(optarg) > 7)
  				caddr.can_addr.tp.tx_id |= CAN_EFF_FLAG;
  			break;
  
  		case 'd':
  			caddr.can_addr.tp.rx_id = strtoul(optarg, (char **)NULL, 16);
  			if (strlen(optarg) > 7)
  				caddr.can_addr.tp.rx_id |= CAN_EFF_FLAG;
  			break;
  
  		case 'x':
  			opts.flags |= CAN_ISOTP_EXTEND_ADDR;
  			opts.ext_address = strtoul(optarg, (char **)NULL, 16) & 0xFF;
  			break;
  
  		case 'p':
  			opts.flags |= CAN_ISOTP_TX_PADDING;
  			opts.txpad_content = strtoul(optarg, (char **)NULL, 16) & 0xFF;
  			break;
  
  		case 'r':
  			opts.flags |= CAN_ISOTP_RX_PADDING;
  			opts.rxpad_content = strtoul(optarg, (char **)NULL, 16) & 0xFF;
  			break;
  
  		case 'P':
  			if (optarg[0] == 'l')
  				opts.flags |= CAN_ISOTP_CHK_PAD_LEN;
  			else if (optarg[0] == 'c')
  				opts.flags |= CAN_ISOTP_CHK_PAD_DATA;
  			else if (optarg[0] == 'a')
  				opts.flags |= (CAN_ISOTP_CHK_PAD_DATA | CAN_ISOTP_CHK_PAD_DATA);
  			else {
  				printf("unknown padding check option '%c'.\n", optarg[0]);
  				print_usage(basename(argv[0]));
  				exit(0);
  			}
  			break;
  
  		case 'b':
  			fcopts.bs = strtoul(optarg, (char **)NULL, 16) & 0xFF;
  			break;
  
  		case 'm':
  			fcopts.stmin = strtoul(optarg, (char **)NULL, 16) & 0xFF;
  			break;
  
  		case 'w':
  			fcopts.wftmax = strtoul(optarg, (char **)NULL, 16) & 0xFF;
  			break;
  
  		case 't':
  			opts.frame_txtime = strtoul(optarg, (char **)NULL, 10);
  			break;
  
  		case 'v':
  			verbose = 1;
  			break;
  
  		case '?':
  			print_usage(basename(argv[0]));
  			exit(0);
  			break;
  
  		default:
  			fprintf(stderr, "Unknown option %c\n", opt);
  			print_usage(basename(argv[0]));
  			exit(1);
  			break;
  		}
  	}
  
  	if ((argc - optind != 1) || (local_port == 0) ||
  	    (caddr.can_addr.tp.tx_id == NO_CAN_ID) ||
  	    (caddr.can_addr.tp.rx_id == NO_CAN_ID)) {
  		print_usage(basename(argv[0]));
  		exit(1);
  	}
    
  	sigemptyset(&sigset);
  	signalaction.sa_handler = &childdied;
  	signalaction.sa_mask = sigset;
  	signalaction.sa_flags = 0;
  	sigaction(SIGCHLD, &signalaction, NULL);  /* signal for dying child */
  
  	if((sl = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
  		perror("inetsocket");
  		exit(1);
  	}
  
  	saddr.sin_family = AF_INET;
  	saddr.sin_addr.s_addr = htonl(INADDR_ANY);
  	saddr.sin_port = htons(local_port);
  
  	while(bind(sl,(struct sockaddr*)&saddr, sizeof(saddr)) < 0) {
  		printf(".");
  		fflush(NULL);
  		usleep(100000);
  	}
  
  	if (listen(sl, 3) != 0) {
  		perror("listen");
  		exit(1);
  	}
  
  	while (1) { 
  		sa = accept(sl,(struct sockaddr *)&clientaddr, &sin_size);
  		if (sa > 0 ){
  
  			if (fork())
  				close(sa);
  			else
  				break;
  		}
  		else {
  			if (errno != EINTR) {
  				/*
  				 * If the cause for the error was NOT the
  				 * signal from a dying child => give an error
  				 */
  				perror("accept");
  				exit(1);
  			}
  		}
  	}
  
  	if ((sc = socket(PF_CAN, SOCK_DGRAM, CAN_ISOTP)) < 0) {
  		perror("socket");
  		exit(1);
  	}
  
  	setsockopt(sc, SOL_CAN_ISOTP, CAN_ISOTP_OPTS, &opts, sizeof(opts));
  	setsockopt(sc, SOL_CAN_ISOTP, CAN_ISOTP_RECV_FC, &fcopts, sizeof(fcopts));
  
  	caddr.can_family = AF_CAN;
  	strcpy(ifr.ifr_name, argv[optind]);
  	if (ioctl(sc, SIOCGIFINDEX, &ifr) < 0) {
  		perror("SIOCGIFINDEX");
  		exit(1);
  	}
  	caddr.can_ifindex = ifr.ifr_ifindex;
  
  	if (bind(sc, (struct sockaddr *)&caddr, caddrlen) < 0) {
  		perror("bind");
  		exit(1);
  	}
  
  	while (1) {
  
  		FD_ZERO(&readfds);
  		FD_SET(sc, &readfds);
  		FD_SET(sa, &readfds);
  
  		ret = select((sc > sa)?sc+1:sa+1, &readfds, NULL, NULL, NULL);
  
  		if (FD_ISSET(sc, &readfds)) {
  
  
  			nbytes = read(sc, &msg, 4096);
  
  			if (nbytes < 1 || nbytes > 4095) {
  				perror("read from isotp socket");
  				exit(1);
  			}
  
  			rxmsg[0] = '<';
  
  			for ( i = 0; i < nbytes; i++)
  				sprintf(rxmsg + 1 + 2*i, "%02X", msg[i]);
  
  			/* finalize string for sending */
  			strcat(rxmsg, ">\n");
  
  			if (verbose)
  				printf("CAN>TCP %s", rxmsg);
  
  			send(sa, rxmsg, strlen(rxmsg), 0);
  		}
  
  
  		if (FD_ISSET(sa, &readfds)) {
  
  			if (read(sa, txmsg+idx, 1) < 1) {
  				perror("read from tcp/ip socket");
  				exit(1);
  			}
  
  			if (!idx) {
  				if (txmsg[0] == '<')
  					idx = 1;
  
  				continue;
  			}
  
  			/* max len is 4095*2 + '<' + '>' = 8192. The buffer index starts with 0 */
  			if (idx > 8191) {
  				idx = 0;
  				continue;
  			}
  
  			if (txmsg[idx] != '>') {
  				idx++;
  				continue;
  			}
  
  			txmsg[idx+1] = 0;
  			idx = 0;
  
  			/* must be an even number of bytes and at least one data byte <XX> */
  			if (strlen(txmsg) < 4 || strlen(txmsg) % 2)
  				continue;
  
  			if (verbose)
  				printf("TCP>CAN %s\n", txmsg);
  
  			nbytes = (strlen(txmsg)-2)/2;
  			if (b64hex(txmsg+1, msg, nbytes) == 0)
  				send(sc, msg, nbytes, 0);
  		}
  	}
  
  	close(sc);
  	close(sa);
  
  	return 0;
  }
  