Linux之CAN小结

Linux Shell操作

查询CAN信息

• ip -details link show can0
  查询CAN的详细信息，包括波特率、标志设置等信息
• ip -details -statistics link show can0
  查询CAN的工作状态
• ifconfig -a
  查询CAN的收发数据包情况，以及中断号
• dmesg | grep “can”
  查询CAN的详细物理信息,包括电压、寄存器、中断等

开启/关闭CAN

• ifconfig can0 down
  关闭CAN
• ifconfig can0 up
  打开CAN
• ip link set can0 up type can
  打开CAN网络
• ip link set can0 down
  关闭CAN 网络

发送/接收CAN数据

• cansend can0 0x11 0x22 0x33 0x44 0x55 0x66 0x77 0x88
  发送默认ID为0x1的can标准帧，数据为0x11 22 33 44 55 66 77 88每次最大8个byte
• cansend can0 -i 0x800 0x11 0x22 0x33 0x44 0x55 0x66 0x77 0x88 -e
  -e 表示扩展帧，CAN_ID最大29bit，标准帧CAN_ID最大11bit -i表示CAN_ID
• cansend can0 -i 0x02 0x11 0x12 --loop=20
  –loop 表示发送20个包
• candump can0
  接收数据
• cansend can0 123#1122334455667788

设置CAN参数

• ip link set can0 type can --help
  can参数设置详解
• ip link set can0 up type can bitrate 800000
  设置can0的波特率为800kbps,CAN网络波特率最大值为1Mbps
• ip link set can0 up type can bitrate 800000 loopback on
  设置回环模式，自发自收，用于测试是硬件是否正常,loopback不一定支持
• List item

虚拟VCAN

• sudo modprobe vcan
  加载虚拟can模块
• sudo ip link add dev vcan0 type vcan
  添加vcan0网卡

Linux CAN编程

主要头文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

CAN重要数据结构

struct ifreq irq;//网络协议结构体
struct sockaddr_can canAddr;//CAN地址
struct can_filter canFilter;//CAN数据过滤
struct can_frame canFrame;//收发数据结构体

struct ifreq

//if.h
struct sockaddr {
	sa_family_t	sa_family;	/* address family, AF_xxx，typedef unsigned short*/
	char		sa_data[14];	/* 14 bytes of protocol address	*/
};

struct if_settings {
	unsigned int type;	/* Type of physical device or protocol */
	unsigned int size;	/* Size of the data allocated by the caller */
	union {
		/* {atm/eth/dsl}_settings anyone ? */
		raw_hdlc_proto		__user *raw_hdlc;
		cisco_proto		__user *cisco;
		fr_proto		__user *fr;
		fr_proto_pvc		__user *fr_pvc;
		fr_proto_pvc_info	__user *fr_pvc_info;

		/* interface settings */
		sync_serial_settings	__user *sync;
		te1_settings		__user *te1;
	} ifs_ifsu;
};

struct ifreq {
#define IFHWADDRLEN	6
	union
	{
		char	ifrn_name[IFNAMSIZ];		/* if name, e.g. "en0" */
	} ifr_ifrn;
	union {
		struct	sockaddr ifru_addr;
		struct	sockaddr ifru_dstaddr;
		struct	sockaddr ifru_broadaddr;
		struct	sockaddr ifru_netmask;
		struct  sockaddr ifru_hwaddr;
		short	ifru_flags;
		int	ifru_ivalue;
		int	ifru_mtu;
		struct  ifmap ifru_map;
		char	ifru_slave[IFNAMSIZ];	/* Just fits the size */
		char	ifru_newname[IFNAMSIZ];
		void __user *	ifru_data;
		struct	if_settings ifru_settings;
	} ifr_ifru;
};

struct sockaddr_can

//can.h
/**
 * struct sockaddr_can - the sockaddr structure for CAN sockets
 * @can_family:  address family number AF_CAN.
 * @can_ifindex: CAN network interface index.
 * @can_addr:    protocol specific address information
 */
struct sockaddr_can {
	__kernel_sa_family_t can_family;/*address family, AF_xxx,typedef unsigned short*/
	int         can_ifindex;
	union {
		/* transport protocol class address information (e.g. ISOTP) */
		struct { canid_t rx_id, tx_id; } tp;

		/* reserved for future CAN protocols address information */
	} can_addr;
};

struct can_filter

//can.h
/**
 * struct can_filter - CAN ID based filter in can_register().
 * @can_id:   relevant bits of CAN ID which are not masked out.
 * @can_mask: CAN mask (see description)
 * Description:
 * A filter matches, when
 *           & mask == can_id & mask
 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
 * filter for error message frames (CAN_ERR_FLAG bit set in mask).
 */
struct can_filter {
	canid_t can_id;
	canid_t can_mask;
};

struct can_frame

//can.h
/**
 * struct can_frame - basic CAN frame structure
 * @can_id:  CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
 * @can_dlc: frame payload length in byte (0 .. 8) aka data length code
 *           N.B. the DLC field from ISO 11898-1 Chapter 8.4.2.3 has a 1:1
 *           mapping of the 'data length code' to the real payload length
 * @__pad:   padding
 * @__res0:  reserved / padding
 * @__res1:  reserved / padding
 * @data:    CAN frame payload (up to 8 byte)
 */
struct can_frame {
	canid_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
	__u8    can_dlc; /* frame payload length in byte (0 .. CAN_MAX_DLEN) */
	__u8    data[CAN_MAX_DLEN] __attribute__((aligned(8)));
};
/*
can_id 为帧的标识符
如果发出的是标准帧， 就使用 can_id 的低 11 位
如果为扩展帧， 就使用 0～ 28 位

can_id 的第 29、 30、 31 位是帧的标志位:
#define CAN_EFF_FLAG 0x80000000U //扩展帧的标识
#define CAN_RTR_FLAG 0x40000000U //远程帧的标识
#define CAN_ERR_FLAG 0x20000000U //错误帧的标识，用于错误检查

*/

CAN的协议域

//can.h
#ifndef AF_CAN
/** CAN address family */
#define AF_CAN	29
/** CAN protocol family */
#define PF_CAN	AF_CAN
#endif
/* particular protocols of the protocol family PF_CAN */
#define CAN_RAW		1 /* RAW sockets */
#define CAN_BCM		2 /* Broadcast Manager */
#define CAN_TP16	3 /* VAG Transport Protocol v1.6 */
#define CAN_TP20	4 /* VAG Transport Protocol v2.0 */
#define CAN_MCNET	5 /* Bosch MCNet */
#define CAN_ISOTP	6 /* ISO 15765-2 Transport Protocol */
#define CAN_NPROTO	7

socket()函数对应的参数

Socket的协议域

//socket.h
/* Supported address families. */
#define AF_UNSPEC	0
#define AF_UNIX		1	/* Unix domain sockets 		*/
#define AF_LOCAL	1	/* POSIX name for AF_UNIX	*/
#define AF_INET		2	/* Internet IP Protocol 	*/
#define AF_AX25		3	/* Amateur Radio AX.25 		*/
#define AF_IPX		4	/* Novell IPX 			*/
#define AF_APPLETALK	5	/* AppleTalk DDP 		*/
#define AF_NETROM	6	/* Amateur Radio NET/ROM 	*/
#define AF_BRIDGE	7	/* Multiprotocol bridge 	*/
#define AF_ATMPVC	8	/* ATM PVCs			*/
#define AF_X25		9	/* Reserved for X.25 project 	*/
#define AF_INET6	10	/* IP version 6			*/
#define AF_ROSE		11	/* Amateur Radio X.25 PLP	*/
#define AF_DECnet	12	/* Reserved for DECnet project	*/
#define AF_NETBEUI	13	/* Reserved for 802.2LLC project*/
#define AF_SECURITY	14	/* Security callback pseudo AF */
#define AF_KEY		15      /* PF_KEY key management API */
#define AF_NETLINK	16
#define AF_ROUTE	AF_NETLINK /* Alias to emulate 4.4BSD */
#define AF_PACKET	17	/* Packet family		*/
#define AF_ASH		18	/* Ash				*/
#define AF_ECONET	19	/* Acorn Econet			*/
#define AF_ATMSVC	20	/* ATM SVCs			*/
#define AF_RDS		21	/* RDS sockets 			*/
#define AF_SNA		22	/* Linux SNA Project (nutters!) */
#define AF_IRDA		23	/* IRDA sockets			*/
#define AF_PPPOX	24	/* PPPoX sockets		*/
#define AF_WANPIPE	25	/* Wanpipe API Sockets */
#define AF_LLC		26	/* Linux LLC			*/
#define AF_IB		27	/* Native InfiniBand address	*/
#define AF_MPLS		28	/* MPLS */
#define AF_CAN		29	/* Controller Area Network      */
#define AF_TIPC		30	/* TIPC sockets			*/
#define AF_BLUETOOTH	31	/* Bluetooth sockets 		*/
#define AF_IUCV		32	/* IUCV sockets			*/
#define AF_RXRPC	33	/* RxRPC sockets 		*/
#define AF_ISDN		34	/* mISDN sockets 		*/
#define AF_PHONET	35	/* Phonet sockets		*/
#define AF_IEEE802154	36	/* IEEE802154 sockets		*/
#define AF_CAIF		37	/* CAIF sockets			*/
#define AF_ALG		38	/* Algorithm sockets		*/
#define AF_NFC		39	/* NFC sockets			*/
#define AF_VSOCK	40	/* vSockets			*/
#define AF_KCM		41	/* Kernel Connection Multiplexor*/
#define AF_QIPCRTR	42	/* Qualcomm IPC Router          */
#define AF_SMC		43	/* smc sockets: reserve number for
				 * PF_SMC protocol family that
				 * reuses AF_INET address family
				 */
#define AF_XDP		44	/* XDP sockets			*/

#define AF_MAX		45	/* For now.. */

/* Protocol families, same as address families. */
#define PF_UNSPEC	AF_UNSPEC
#define PF_UNIX		AF_UNIX
#define PF_LOCAL	AF_LOCAL
#define PF_INET		AF_INET
#define PF_AX25		AF_AX25
#define PF_IPX		AF_IPX
#define PF_APPLETALK	AF_APPLETALK
#define	PF_NETROM	AF_NETROM
#define PF_BRIDGE	AF_BRIDGE
#define PF_ATMPVC	AF_ATMPVC
#define PF_X25		AF_X25
#define PF_INET6	AF_INET6
#define PF_ROSE		AF_ROSE
#define PF_DECnet	AF_DECnet
#define PF_NETBEUI	AF_NETBEUI
#define PF_SECURITY	AF_SECURITY
#define PF_KEY		AF_KEY
#define PF_NETLINK	AF_NETLINK
#define PF_ROUTE	AF_ROUTE
#define PF_PACKET	AF_PACKET
#define PF_ASH		AF_ASH
#define PF_ECONET	AF_ECONET
#define PF_ATMSVC	AF_ATMSVC
#define PF_RDS		AF_RDS
#define PF_SNA		AF_SNA
#define PF_IRDA		AF_IRDA
#define PF_PPPOX	AF_PPPOX
#define PF_WANPIPE	AF_WANPIPE
#define PF_LLC		AF_LLC
#define PF_IB		AF_IB
#define PF_MPLS		AF_MPLS
#define PF_CAN		AF_CAN
#define PF_TIPC		AF_TIPC
#define PF_BLUETOOTH	AF_BLUETOOTH
#define PF_IUCV		AF_IUCV
#define PF_RXRPC	AF_RXRPC
#define PF_ISDN		AF_ISDN
#define PF_PHONET	AF_PHONET
#define PF_IEEE802154	AF_IEEE802154
#define PF_CAIF		AF_CAIF
#define PF_ALG		AF_ALG
#define PF_NFC		AF_NFC
#define PF_VSOCK	AF_VSOCK
#define PF_KCM		AF_KCM
#define PF_QIPCRTR	AF_QIPCRTR
#define PF_SMC		AF_SMC
#define PF_XDP		AF_XDP
#define PF_MAX		AF_MAX

Socket的网络类型

//net.h
/**
 * enum sock_type - Socket types
 * @SOCK_STREAM: stream (connection) socket
 * @SOCK_DGRAM: datagram (conn.less) socket
 * @SOCK_RAW: raw socket
 * @SOCK_RDM: reliably-delivered message
 * @SOCK_SEQPACKET: sequential packet socket
 * @SOCK_DCCP: Datagram Congestion Control Protocol socket
 * @SOCK_PACKET: linux specific way of getting packets at the dev level.
 *		  For writing rarp and other similar things on the user level.
 * When adding some new socket type please
 * grep ARCH_HAS_SOCKET_TYPE include/asm-* /socket.h, at least MIPS
 * overrides this enum for binary compat reasons.
 */
enum sock_type {
	SOCK_STREAM	= 1,
	SOCK_DGRAM = 2,
	SOCK_RAW	= 3,
	SOCK_RDM	= 4,
	SOCK_SEQPACKET	= 5,
	SOCK_DCCP	= 6,
	SOCK_PACKET	= 10,
};在这里插入代码片

Socket协议

//in.h
enum {
  IPPROTO_IP = 0,		/* Dummy protocol for TCP		*/
#define IPPROTO_IP		IPPROTO_IP
  IPPROTO_ICMP = 1,		/* Internet Control Message Protocol	*/
#define IPPROTO_ICMP		IPPROTO_ICMP
  IPPROTO_IGMP = 2,		/* Internet Group Management Protocol	*/
#define IPPROTO_IGMP		IPPROTO_IGMP
  IPPROTO_IPIP = 4,		/* IPIP tunnels (older KA9Q tunnels use 94) */
#define IPPROTO_IPIP		IPPROTO_IPIP
  IPPROTO_TCP = 6,		/* Transmission Control Protocol	*/
#define IPPROTO_TCP		IPPROTO_TCP
  IPPROTO_EGP = 8,		/* Exterior Gateway Protocol		*/
#define IPPROTO_EGP		IPPROTO_EGP
  IPPROTO_PUP = 12,		/* PUP protocol				*/
#define IPPROTO_PUP		IPPROTO_PUP
  IPPROTO_UDP = 17,		/* User Datagram Protocol		*/
#define IPPROTO_UDP		IPPROTO_UDP
  IPPROTO_IDP = 22,		/* XNS IDP protocol			*/
#define IPPROTO_IDP		IPPROTO_IDP
  IPPROTO_TP = 29,		/* SO Transport Protocol Class 4	*/
#define IPPROTO_TP		IPPROTO_TP
  IPPROTO_DCCP = 33,		/* Datagram Congestion Control Protocol */
#define IPPROTO_DCCP		IPPROTO_DCCP
  IPPROTO_IPV6 = 41,		/* IPv6-in-IPv4 tunnelling		*/
#define IPPROTO_IPV6		IPPROTO_IPV6
  IPPROTO_RSVP = 46,		/* RSVP Protocol			*/
#define IPPROTO_RSVP		IPPROTO_RSVP
  IPPROTO_GRE = 47,		/* Cisco GRE tunnels (rfc 1701,1702)	*/
#define IPPROTO_GRE		IPPROTO_GRE
  IPPROTO_ESP = 50,		/* Encapsulation Security Payload protocol */
#define IPPROTO_ESP		IPPROTO_ESP
  IPPROTO_AH = 51,		/* Authentication Header protocol	*/
#define IPPROTO_AH		IPPROTO_AH
  IPPROTO_MTP = 92,		/* Multicast Transport Protocol		*/
#define IPPROTO_MTP		IPPROTO_MTP
  IPPROTO_BEETPH = 94,		/* IP option pseudo header for BEET	*/
#define IPPROTO_BEETPH		IPPROTO_BEETPH
  IPPROTO_ENCAP = 98,		/* Encapsulation Header			*/
#define IPPROTO_ENCAP		IPPROTO_ENCAP
  IPPROTO_PIM = 103,		/* Protocol Independent Multicast	*/
#define IPPROTO_PIM		IPPROTO_PIM
  IPPROTO_COMP = 108,		/* Compression Header Protocol		*/
#define IPPROTO_COMP		IPPROTO_COMP
  IPPROTO_SCTP = 132,		/* Stream Control Transport Protocol	*/
#define IPPROTO_SCTP		IPPROTO_SCTP
  IPPROTO_UDPLITE = 136,	/* UDP-Lite (RFC 3828)			*/
#define IPPROTO_UDPLITE		IPPROTO_UDPLITE
  IPPROTO_MPLS = 137,		/* MPLS in IP (RFC 4023)		*/
#define IPPROTO_MPLS		IPPROTO_MPLS
  IPPROTO_RAW = 255,		/* Raw IP packets			*/
#define IPPROTO_RAW		IPPROTO_RAW
  IPPROTO_MAX
};

Socket的IOCTL

//sockios.h
/* Linux-specific socket ioctls */
#define SIOCINQ		FIONREAD
#define SIOCOUTQ	TIOCOUTQ        /* output queue size (not sent + not acked) */

#define SOCK_IOC_TYPE	0x89

/* Routing table calls. */
#define SIOCADDRT	0x890B		/* add routing table entry	*/
#define SIOCDELRT	0x890C		/* delete routing table entry	*/
#define SIOCRTMSG	0x890D		/* unused			*/

/* Socket configuration controls. */
#define SIOCGIFNAME	0x8910		/* get iface name		*/
#define SIOCSIFLINK	0x8911		/* set iface channel		*/
#define SIOCGIFCONF	0x8912		/* get iface list		*/
#define SIOCGIFFLAGS	0x8913		/* get flags			*/
#define SIOCSIFFLAGS	0x8914		/* set flags			*/
#define SIOCGIFADDR	0x8915		/* get PA address		*/
#define SIOCSIFADDR	0x8916		/* set PA address		*/
#define SIOCGIFDSTADDR	0x8917		/* get remote PA address	*/
#define SIOCSIFDSTADDR	0x8918		/* set remote PA address	*/
#define SIOCGIFBRDADDR	0x8919		/* get broadcast PA address	*/
#define SIOCSIFBRDADDR	0x891a		/* set broadcast PA address	*/
#define SIOCGIFNETMASK	0x891b		/* get network PA mask		*/
#define SIOCSIFNETMASK	0x891c		/* set network PA mask		*/
#define SIOCGIFMETRIC	0x891d		/* get metric			*/
#define SIOCSIFMETRIC	0x891e		/* set metric			*/
#define SIOCGIFMEM	0x891f		/* get memory address (BSD)	*/
#define SIOCSIFMEM	0x8920		/* set memory address (BSD)	*/
#define SIOCGIFMTU	0x8921		/* get MTU size			*/
#define SIOCSIFMTU	0x8922		/* set MTU size			*/
#define SIOCSIFNAME	0x8923		/* set interface name */
#define	SIOCSIFHWADDR	0x8924		/* set hardware address 	*/
#define SIOCGIFENCAP	0x8925		/* get/set encapsulations       */
#define SIOCSIFENCAP	0x8926		
#define SIOCGIFHWADDR	0x8927		/* Get hardware address		*/
#define SIOCGIFSLAVE	0x8929		/* Driver slaving support	*/
#define SIOCSIFSLAVE	0x8930
#define SIOCADDMULTI	0x8931		/* Multicast address lists	*/
#define SIOCDELMULTI	0x8932
#define SIOCGIFINDEX	0x8933		/* name -> if_index mapping	*/
#define SIOGIFINDEX	SIOCGIFINDEX	/* misprint compatibility :-)	*/
#define SIOCSIFPFLAGS	0x8934		/* set/get extended flags set	*/
#define SIOCGIFPFLAGS	0x8935
#define SIOCDIFADDR	0x8936		/* delete PA address		*/
#define	SIOCSIFHWBROADCAST	0x8937	/* set hardware broadcast addr	*/
#define SIOCGIFCOUNT	0x8938		/* get number of devices */

#define SIOCGIFBR	0x8940		/* Bridging support		*/
#define SIOCSIFBR	0x8941		/* Set bridging options 	*/

#define SIOCGIFTXQLEN	0x8942		/* Get the tx queue length	*/
#define SIOCSIFTXQLEN	0x8943		/* Set the tx queue length 	*/

/* SIOCGIFDIVERT was:	0x8944		Frame diversion support */
/* SIOCSIFDIVERT was:	0x8945		Set frame diversion options */

#define SIOCETHTOOL	0x8946		/* Ethtool interface		*/

#define SIOCGMIIPHY	0x8947		/* Get address of MII PHY in use. */
#define SIOCGMIIREG	0x8948		/* Read MII PHY register.	*/
#define SIOCSMIIREG	0x8949		/* Write MII PHY register.	*/

#define SIOCWANDEV	0x894A		/* get/set netdev parameters	*/

#define SIOCOUTQNSD	0x894B		/* output queue size (not sent only) */
#define SIOCGSKNS	0x894C		/* get socket network namespace */

/* ARP cache control calls. */
		    /*  0x8950 - 0x8952  * obsolete calls, don't re-use */
#define SIOCDARP	0x8953		/* delete ARP table entry	*/
#define SIOCGARP	0x8954		/* get ARP table entry		*/
#define SIOCSARP	0x8955		/* set ARP table entry		*/

/* RARP cache control calls. */
#define SIOCDRARP	0x8960		/* delete RARP table entry	*/
#define SIOCGRARP	0x8961		/* get RARP table entry		*/
#define SIOCSRARP	0x8962		/* set RARP table entry		*/

/* Driver configuration calls */

#define SIOCGIFMAP	0x8970		/* Get device parameters	*/
#define SIOCSIFMAP	0x8971		/* Set device parameters	*/

/* DLCI configuration calls */

#define SIOCADDDLCI	0x8980		/* Create new DLCI device	*/
#define SIOCDELDLCI	0x8981		/* Delete DLCI device		*/

#define SIOCGIFVLAN	0x8982		/* 802.1Q VLAN support		*/
#define SIOCSIFVLAN	0x8983		/* Set 802.1Q VLAN options 	*/

/* bonding calls */

#define SIOCBONDENSLAVE	0x8990		/* enslave a device to the bond */
#define SIOCBONDRELEASE 0x8991		/* release a slave from the bond*/
#define SIOCBONDSETHWADDR      0x8992	/* set the hw addr of the bond  */
#define SIOCBONDSLAVEINFOQUERY 0x8993   /* rtn info about slave state   */
#define SIOCBONDINFOQUERY      0x8994	/* rtn info about bond state    */
#define SIOCBONDCHANGEACTIVE   0x8995   /* update to a new active slave */
			
/* bridge calls */
#define SIOCBRADDBR     0x89a0		/* create new bridge device     */
#define SIOCBRDELBR     0x89a1		/* remove bridge device         */
#define SIOCBRADDIF	0x89a2		/* add interface to bridge      */
#define SIOCBRDELIF	0x89a3		/* remove interface from bridge */

/* hardware time stamping: parameters in linux/net_tstamp.h */
#define SIOCSHWTSTAMP	0x89b0		/* set and get config		*/
#define SIOCGHWTSTAMP	0x89b1		/* get config			*/

/* Device private ioctl calls */

/*
 *	These 16 ioctls are available to devices via the do_ioctl() device
 *	vector. Each device should include this file and redefine these names
 *	as their own. Because these are device dependent it is a good idea
 *	_NOT_ to issue them to random objects and hope.
 *
 *	THESE IOCTLS ARE _DEPRECATED_ AND WILL DISAPPEAR IN 2.5.X -DaveM
 */
 
#define SIOCDEVPRIVATE	0x89F0	/* to 89FF */

/*
 *	These 16 ioctl calls are protocol private
 */
 
#define SIOCPROTOPRIVATE 0x89E0 /* to 89EF */

CAN编码流程

示例代码

int canSocket;
bool can_init()
{
    int nRet;
    int nFlags;
    struct ifreq ifr;
    struct sockaddr_can canAddr;
    struct can_filter canFilter;
    /* 创建socket */
    canSocket = socket(PF_CAN, SOCK_RAW, CAN_RAW);
    if (canSocket  < 0) {
        perror("create can socket failed");
        return false;
    }

    /* 设置为非阻塞 */
    nFlags = fcntl(canSocket, F_GETFL, 0);
    fcntl(canSocket, F_SETFL, nFlags | O_NONBLOCK);
    /* 获取can口属性 */
    strcpy(ifr.ifr_name, (const char *)"can0");
    nRet = ioctl(canSocket, SIOCGIFINDEX, &ifr);
    if (nRet < 0) {
        perror("ioctl can failed");
        close(tcanSocket);
        canSocket = 0;
        return false;
    }

    /* 绑定can口 */
    canAddr.can_family = AF_CAN;
    canAddr.can_ifindex = ifr.ifr_ifindex;
    nRet = bind(canSocket, (struct sockaddr *)&canAddr, sizeof(canAddr));
    if (nRet < 0) {
        perror("bind can socket failed");
        close(canSocket);
        this->u8Socket = 0;
        return false;
    }

    /* 设置过滤 */
    canFilter.can_id = filterID;
    canFilter.can_mask = CAN_SFF_MASK;
    //int getsockopt(int sock, int level, int optname, void *optval, socklen_t *optlen)
    nRet = setsockopt(canSocket, SOL_CAN_RAW, CAN_RAW_FILTER, &canFilter, sizeof(struct can_filter));
    if (nRet < 0) {
        perror("setsockopt failed");
        return false;
    }
    
    return true;
}

ssize_t can_send(int ID, char *pData, char len)
{
    ssize_t nBytes;
    struct can_frame canSendFrame = {0};

    if (u8Len > CAN_MAX_DLEN){
        return -1;
    }
    canSendFrame.can_id = ID;
    canSendFrame.can_dlc = 8;
    memcpy(canSendFrame.data, pData, len);
    nBytes = write(canSocket, &canSendFrame, sizeof(canSendFrame));
    if (nBytes <= (sizeof(can_frame) - CAN_MAX_DLEN)) {
        perror("can socket write failed");
        return -1;
    }

    return (nBytes - (sizeof(can_frame) - CAN_MAX_DLEN));
}

ssize_t can_recv(char *pData)
{
    ssize_t nBytes;
    struct can_frame canRecvFrame = {0};
    if (NULL == pData){
        return -1;
    }

    nBytes = read(canSocket, &canRecvFrame, sizeof(can_frame));
    if (nBytes < (sizeof(can_frame) - CAN_MAX_DLEN)) {
        perror("can socket read failed");
        return -1;
    }
    memcpy(pData, canRecvFrame.data, (nBytes - (sizeof(can_frame) - CAN_MAX_DLEN)));

    return (nBytes - (sizeof(can_frame) - CAN_MAX_DLEN));
}

void can_exit()
{
	close(canSocket);
}