Linux CAN通信(一)
CANBUS
Linux CAN通信
本文旨在利用虚拟can接口实现简单的通信，为后续canbus通信学习打下基础。
- 创建虚拟CAN接口
加载vcan内核模块: sudo modprobe vcan
创建虚拟CAN接口: sudo ip link add dev vcan0 type vcan
将虚拟CAN接口处于在线状态: sudo ip link set up vcan0
通过命令ip addr | grep "can" 来验证是否可用并处于在线状态
- 使用 can-utils 测试CAN通信 基于虚拟CAN接口，测试一下CAN通信情况
sudo apt install can-utils - 打开两个终端接口（一个用来查看、一个用来发送）
#查看
candump -tz vcan0
#发送
cansend vcan0 123#00FFAA5501020304
CAN通信参考代码
CAN数据读取
#include
#include
#include
#include
#include
#include
#include
#include
#include
int main(void)
{
struct ifreq ifr = {0};
struct sockaddr_can can_addr = {0};
struct can_frame frame = {0};
int sockfd = -1;
int i;
int ret;
/* 打开套接字 */
sockfd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
if(0 > sockfd) {
perror("socket error");
exit(EXIT_FAILURE);
}
/* 指定can0设备 */
strcpy(ifr.ifr_name, "vcan0");
ioctl(sockfd, SIOCGIFINDEX, &ifr);
can_addr.can_family = AF_CAN;
can_addr.can_ifindex = ifr.ifr_ifindex;
/* 将can0与套接字进行绑定 */
ret = bind(sockfd, (struct sockaddr *)&can_addr, sizeof(can_addr));
if (0 > ret) {
perror("bind error");
close(sockfd);
exit(EXIT_FAILURE);
}
/* 设置过滤规则 */
//setsockopt(sockfd, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0);
/* 接收数据 */
for ( ; ; ) {
if (0 > read(sockfd, &frame, sizeof(struct can_frame))) {
perror("read error");
break;
}
/* 校验是否接收到错误帧 */
if (frame.can_id & CAN_ERR_FLAG) {
printf("Error frame!\n");
break;
}
/* 校验帧格式 */
if (frame.can_id & CAN_EFF_FLAG) //扩展帧
printf("扩展帧 <0x%08x> ", frame.can_id & CAN_EFF_MASK);
else //标准帧
printf("标准帧 <0x%03x> ", frame.can_id & CAN_SFF_MASK);
/* 校验帧类型：数据帧还是远程帧 */
if (frame.can_id & CAN_RTR_FLAG) {
printf("remote request\n");
continue;
}
/* 打印数据长度 */
printf("[%d] ", frame.can_dlc);
/* 打印数据 */
for (i = 0; i < frame.can_dlc; i++)
printf("%02x ", frame.data[i]);
printf("\n");
}
/* 关闭套接字 */
close(sockfd);
exit(EXIT_SUCCESS);
}
CAN数据发送
#include
#include
#include
#include
#include
#include
#include
#include
#include
int main(void)
{
struct ifreq ifr = {0};
struct sockaddr_can can_addr = {0};
struct can_frame frame = {0};
int sockfd = -1;
int ret;
/* 打开套接字 */
sockfd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
if(0 > sockfd) {
perror("socket error");
exit(EXIT_FAILURE);
}
/* 指定can0设备 */
strcpy(ifr.ifr_name, "vcan0");
ioctl(sockfd, SIOCGIFINDEX, &ifr);
can_addr.can_family = AF_CAN;
can_addr.can_ifindex = ifr.ifr_ifindex;
/* 将can0与套接字进行绑定 */
ret = bind(sockfd, (struct sockaddr *)&can_addr, sizeof(can_addr));
if (0 > ret) {
perror("bind error");
close(sockfd);
exit(EXIT_FAILURE);
}
/* 设置过滤规则：不接受任何报文、仅发送数据 */
setsockopt(sockfd, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0);
/* 发送数据 */
frame.data[0] = 0xA0;
frame.data[1] = 0xB0;
frame.data[2] = 0xC0;
frame.data[3] = 0xD0;
frame.data[4] = 0xE0;
frame.data[5] = 0xF0;
frame.can_dlc = 6; //一次发送6个字节数据
frame.can_id = 0x123;//帧ID为0x123,标准帧
for ( ; ; ) {
ret = write(sockfd, &frame, sizeof(frame)); //发送数据
if(sizeof(frame) != ret) { //如果ret不等于帧长度，就说明发送失败
perror("write error");
goto out;
}
sleep(1); //一秒钟发送一次
}
out:
/* 关闭套接字 */
close(sockfd);
exit(EXIT_SUCCESS);
}