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/*
* Copyright 2015 Max Staudt
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as published
* by the Free Software Foundation.
*/
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/can.h>
#include <linux/can/raw.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <endian.h>
static int base_id = 0x420;
static int my_id = 0x1a;
static int next_id = 0x19; //myid
static int ignore_counter = 10;
static void on_nm_frame(int socket)
{
struct can_frame frame;
struct sockaddr_can addr;
int ret;
socklen_t len;
ret = recvfrom(socket, &frame, sizeof(struct can_frame), 0,
(struct sockaddr *)&addr, &len);
if (ret < 0) {
perror("recvfrom");
exit(1);
}
if (frame.can_id >> 5 == 0x420 >> 5) {
printf("Received NM frame from %03x\n", frame.can_id);
}
if (frame.can_id == base_id + my_id) {
printf("Skipping my own NM frame.\n");
return;
}
switch (frame.data[1]) {
case 01:
if (frame.data[0] == my_id) {
struct can_frame txframe = {.can_id = base_id + next_id,
.can_dlc = 8,
.data = {next_id, 01, 00, 00, 00, 00, 00, 00},
};
ssize_t tmp = write(socket, &txframe, sizeof(txframe));
if (tmp != sizeof(txframe)) {
perror("write socket");
//return 1;
}
}
break;
case 02:
if (ignore_counter > 0) {
ignore_counter--;
break;
}
if (next_id <= my_id
? frame.can_id - base_id < next_id
: next_id == my_id || frame.can_id - base_id < next_id) {
next_id = frame.can_id - base_id;
struct can_frame txframe = {.can_id = base_id + my_id,
.can_dlc = 8,
.data = {my_id, 02, 01, 04, 00, 04, 00, 00},
};
ssize_t tmp = write(socket, &txframe, sizeof(txframe));
if (tmp != sizeof(txframe)) {
perror("write socket");
//return 1;
}
}
break;
}
}
static int net_init(char *ifname)
{
int s;
int recv_own_msgs;
struct sockaddr_can addr;
struct ifreq ifr;
s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
if (s < 0) {
perror("socket");
exit(1);
}
memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name));
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
perror("SIOCGIFINDEX");
exit(1);
}
memset(&addr, 0, sizeof(addr));
addr.can_family = AF_CAN;
addr.can_ifindex = ifr.ifr_ifindex;
if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("bind");
return 0;
}
recv_own_msgs = 0; /* 0 = disabled (default), 1 = enabled */
setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS,
&recv_own_msgs, sizeof(recv_own_msgs));
return s;
}
int main(int argc, char **argv)
{
fd_set rdfs;
int s;
if (argc != 2) {
printf("syntax: %s IFNAME\n", argv[0]);
exit(1);
}
s = net_init(argv[1]);
while (1) {
FD_ZERO(&rdfs);
FD_SET(s, &rdfs);
if (select(s+1, &rdfs, NULL, NULL, NULL) < 0) {
perror("select");
return 1;
}
if (FD_ISSET(s, &rdfs)) {
on_nm_frame(s);
continue;
}
}
return 0;
}
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