CAN总线开发实例

下面通过实例来说明CAN总线接口的使用方法。在本例中，有两个进程，其中一个进程负责报文的发送(标识符为0x11和0x22)，另一个进程负责报文的接收和过滤(只接收标识符为0x11的报文)。
/* 1.报文发送程序 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/can.h>
#include <linux/can/raw.h>
int main()
{
 int s, nbytes;
struct sockaddr_can addr;
struct ifreq ifr;
struct can_frame frame[2] = {{0}};
s = socket(PF_CAN, SOCK_RAW, CAN_RAW);  //创建套接字
strcpy(ifr.ifr_name, "can0" );
ioctl(s, SIOCGIFINDEX, &ifr);     //指定can0设备
addr.can_family = AF_CAN;
addr.can_ifindex = ifr.ifr_ifindex;
bind(s, (struct sockaddr *)&addr, sizeof(addr));   //将套接字与can0绑定
//禁用过滤规则，本进程不接收报文，只负责发送
  setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0);
  //生成两个报文
frame[0].can_id = 0x11;
frame[0]. can_dlc = 1;
frame[0].data[0] = 'Y';
frame[0].can_id = 0x22;
frame[0]. can_dlc = 1;
frame[0].data[0] = 'N';
//循环发送两个报文
while(1) {
nbytes = write(s, &frame[0], sizeof(frame[0]));  //发送frame[0]
if (nbytes != sizeof(frame[0])) {
    printf("Send Error frame[0]\n!");
    break;        //发送错误，退出
}
 sleep(1);
nbytes = write(s, &frame[1], sizeof(frame[1]));  //发送frame[1]
if (nbytes != sizeof(frame[0])) {
    printf("Send Error frame[1]\n!");
    break;
}
 sleep(1);
}
close(s);
return 0;
}
/* 2. 报文过滤接收程序 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/can.h>
#include <linux/can/raw.h>
int main()
{
int s, nbytes;
struct sockaddr_can addr;
struct ifreq ifr;
struct can_frame frame;
struct can_filter rfilter[1];
s = socket(PF_CAN, SOCK_RAW, CAN_RAW);  //创建套接字
strcpy(ifr.ifr_name, "can0" );
ioctl(s, SIOCGIFINDEX, &ifr);     //指定can0设备
addr.can_family = AF_CAN;
addr.can_ifindex = ifr.ifr_ifindex;
bind(s, (struct sockaddr *)&addr, sizeof(addr));   //将套接字与can0绑定
  //定义接收规则，只接收表示符等于0x11的报文
rfilter[0].can_id   = 0x11;
rfilter[0].can_mask = CAN_SFF_MASK;
//设置过滤规则
setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter));
  while(1) {
   nbytes = read(s, &frame, sizeof(frame));   //接收报文
   //显示报文
if (nbytes > 0) {
printf(“ID=0x%X DLC=%d data[0]=0x%X\n”, frame.can_id,
frame.can_dlc, frame.data[0]);
}
}
close(s);
return 0;
}