Linux SocketCan client server demo hacking

Posted 2020-06-30 zengjf

/***********************************************************************
 *           Linux SocketCan client server demo hacking
 * 说明：
 *     本文主要是解读Linux上的SocketCan的基本使用方法，内容和Linux上的
 * 网络编程差不多。
 *  
 *                                    2016-3-28 深圳 南山平山村 曾剑锋
 **********************************************************************/

一、cat client.c
    #include <sys/ioctl.h>
    #include <net/if.h>
    #include <linux/can.h>
    
    #ifndef PF_CAN
    #define PF_CAN 29
    #endif
    
    #ifndef AF_CAN
    #define AF_CAN PF_CAN
    #endif
    
    int main()
    {
        int s;
        unsigned long nbytes;
        struct sockaddr_can addr;
        struct ifreq ifr;
        struct can_frame frame;
    
        // 创建一个SocketCan
        s = socket(PF_CAN,SOCK_RAW,CAN_RAW);
    
        // 设置一些参数，这个是使用的can网络的设备号
        strcpy((char *)(ifr.ifr_name),"can0");
        ioctl(s,SIOCGIFINDEX,&ifr);
        printf("can0 can_ifindex = %x\n",ifr.ifr_ifindex);
    
        // 设置使用CAN协议
        addr.can_family = AF_CAN;
        addr.can_ifindex = ifr.ifr_ifindex;
        bind(s,(struct sockaddr*)&addr,sizeof(addr));
    
        // 设置发送到的设备id
        frame.can_id = 0x123;
        strcpy((char *)frame.data,"hello");
        frame.can_dlc = strlen(frame.data);
    
        printf("Send a CAN frame from interface %s\n",ifr.ifr_name);
    
        // 发送数据
        nbytes = sendto(s,&frame,sizeof(struct can_frame),0,(struct sockaddr*)&addr,sizeof(addr));
        
        return 0;
    }

二、cat server.c
    #include <sys/ioctl.h>
    #include <net/if.h>
    #include <linux/can.h>
    
    #ifndef PF_CAN
    #define PF_CAN 29
    #endif
    
    #ifndef AF_CAN
    #define AF_CAN PF_CAN
    #endif
    
    int main()
    {
        int s;
        unsigned long nbytes,len;
        struct sockaddr_can addr;
        struct ifreq ifr;
        struct can_frame frame;
    
        // 创建一个SocketCan
        s = socket(PF_CAN,SOCK_RAW,CAN_RAW);
    
        // 指定使用的Can网络
        strcpy(ifr.ifr_name,"can0");
        ioctl(s,SIOCGIFINDEX,&ifr);
        printf("can0 can_ifindex = %x\n",ifr.ifr_ifindex);
    
        // 指定使用的协议，并绑定
        //bind to all enabled can interface
        addr.can_family = AF_CAN;
        addr.can_ifindex =0;
        bind(s,(struct sockaddr*)&addr,sizeof(addr));
    
        // 获取数据
        nbytes = recvfrom(s,&frame,sizeof(struct can_frame),0,(struct sockaddr *)&addr,&len);
        
        /*get interface name of the received CAN frame*/
        ifr.ifr_ifindex = addr.can_ifindex;
        ioctl(s,SIOCGIFNAME,&ifr);
        printf("Received a CAN frame from interface %s\n",ifr.ifr_name);
        printf("frame message\n"
            "--can_id = %x\n"
            "--can_dlc = %x\n"
            "--data = %s\n",frame.can_id,frame.can_dlc,frame.data);
    
        return 0;
    }