CAN总线源代码

#include "lib.h" //*------------------------------------------------------------------------------------------------ //* 函数名称: InitCanDevice //* 功能描述: 初始化can接口打开设备描述符 //* 入口参数: //* -- CanId: - CAN口设备号 //* -- Rate : -CAN口的速率 //* //* 返回值 : 返回一个int型的can描述符 //* 备注 : 无 //*------------------------------------------------------------------------------------------------ int InitCanDevice(unsigned int CanId,unsigned int Rate) { char Command[100]; int sdcan=0;//套接字描述符 char ptr[20];//存放设备名字 char dev[20]; struct sockaddr_can addr; int nbytes; struct ifreq ifr; sprintf(Command,"ifconfig can%d down",CanId); if(system(Command)>=0) { printf("shut down the can%d is sucessful\n",CanId); }else { printf("shut down the can%d is failed\n",CanId); exit(1); } sprintf(Command,"ip link set can%d type can bitrate %d",CanId,Rate); if(system(Command)>=0) { printf("set the can%d bitrate %d is sucessful\n",CanId,Rate); }else { printf("set the can%d bitrate %d is failed\n",CanId,Rate); exit(1); } sprintf(Command,"ifconfig can%d up",CanId); if(system(Command)>=0) { printf("start the can%d is sucessful\n",CanId); }else { printf("start the can%d is failed\n",CanId); exit(1); } sprintf(dev,"can%d",CanId); strcpy(ptr,dev); sdcan = socket(PF_CAN, SOCK_RAW, CAN_RAW);// 创建套接字描述符 if (sdcan < 0) { perror("socket"); exit (1); } nbytes = strlen(ptr);//判断设备名长度 if (nbytes >= IFNAMSIZ) //如果设备名过长，则提示 { fprintf(stderr, "name of CAN device '%s' is too long!\n", ptr); exit (1); } addr.can_family = AF_CAN;//协议族 memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name)); strncpy(ifr.ifr_name, ptr, nbytes);//拷贝设备名 printf("using interface name '%s'.\n", ifr.ifr_name); if (ioctl(sdcan, SIOCGIFINDEX, &ifr) < 0) //把 接口 的 索引 存入 ifr_ifindex { perror("SIOCGIFINDEX"); exit(1); } addr.can_ifindex = ifr.ifr_ifindex; if (bind(sdcan, (struct sockaddr *)&addr, sizeof(addr)) < 0)//绑定 { perror("bind"); exit (1); } return sdcan; } //*------------------------------------------------------------------------------------------------ //* 函数名称: ReadCanData //* 功能描述: 读取打开的CAN口缓冲区里的数 //* 入口参数: //* -- sdcan: - CAN口设备描述符 //* -- frame: -CAN帧结构体 //* //* 返回值 : 返回一个int型数读成功返回1，失败返回0 //* 备注 : 无 //*------------------------------------------------------------------------------------------------ int ReadCanData(int sdcan,struct can_frame *frame) { char *frame_type=NULL; int nbytes; int dlc; struct iovec iov; struct msghdr msg; iov.iov_base = &frame; msg.msg_iov = &iov; // 指向结构体struct iovec指针，记录数据内容 //接受数据帧 nbytes = read(sdcan, frame, sizeof(struct can_frame)); //读取数据失败原因判断 if (nbytes < 0) { perror("read"); return 0; } if (nbytes < sizeof(struct can_frame)) //如果读取到的数据帧小于can帧的结构，为不完整的数据帧 { fprintf(stderr, "read: incomplete CAN frame\n"); return 0; } dlc = (frame->can_dlc > 8)? 8 :frame->can_dlc;//判断帧的数据长度，最大值为8 //判断帧类型 if (frame->can_id & CAN_ERR_FLAG) //错误帧 { frame->can_id &= (CAN_ERR_MASK|CAN_ERR_FLAG); frame_type="ERR"; } else if (frame->can_id & CAN_EFF_FLAG) //扩展帧 { frame->can_id &= CAN_EFF_MASK;//标准帧 frame_type="EFF"; } else { frame->can_id &= CAN_SFF_MASK;//标准帧 frame_type="SFF"; } return 1; } //*------------------------------------------------------------------------------------------------ //* 函数名称: WriteCanData //* 功能描述: 写入数据到CAN设备 //* 入口参数: //* -- sdcan: - CAN口设备描述符 //* -- frame: -CAN帧结构体 //* //* 返回值 : 返回一个int型数读成功返回1，失败返回0 //* 备注 : 无 //*------------------------------------------------------------------------------------------------ int WriteCanData(int sdcan,struct can_frame frame) { int nbytes=0; printf("write the %.8x %.2x %.2x %.2x %.2x %.2x %.2x %.2x %.2x %.2x \n",frame.can_id,frame.can_dlc,frame.data[0],frame.data[1],frame.data[2],frame.data[3],frame.data[4],frame.data[5],frame.data[6],frame.data[7]); nbytes = write(sdcan, &frame, sizeof(struct can_frame)); //发送数据 //数据发送错误原因判断 if (nbytes < 0) { if (errno != ENOBUFS) { perror("write"); return 0; } }else if (nbytes < sizeof(struct can_frame)) { fprintf(stderr, "write: incomplete CAN frame\n"); return 0; } return 1; } //*------------------------------------------------------------------------------------------------ //* 函数名称: CloseSd //* 功能描述:关闭CAN设备 //* 入口参数: //* -- sdcan: - CAN口设备描述符 //* 返回值 : 无 //* 备注 : 无 //*------------------------------------------------------------------------------------------------ void CloseSd(int sdcan) { close(sdcan); }