socketcan 广播通信代码

以下是一个使用BCM模块进行CAN总线广播通信的简单示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/can.h>
#include <linux/can/bcm.h>

#define CAN_INTERFACE "can0"   // CAN总线接口名称
#define CAN_ID 0x123           // 广播消息ID
#define CAN_DLC 8              // 广播消息数据长度
#define CAN_PERIOD 100000      // 广播周期，单位为微秒

int main(void)
{
    int sock = socket(PF_CAN, SOCK_DGRAM, CAN_BCM);
    if (sock < 0) {
        perror("socket");
        exit(1);
    }

    struct ifreq ifr;
    strcpy(ifr.ifr_name, CAN_INTERFACE);
    ioctl(sock, SIOCGIFINDEX, &ifr);

    struct sockaddr_can addr;
    memset(&addr, 0, sizeof(addr));
    addr.can_family = AF_CAN;
    addr.can_ifindex = ifr.ifr_ifindex;

    if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        perror("bind");
        exit(1);
    }

    struct bcm_msg_head msg_head;
    memset(&msg_head, 0, sizeof(msg_head));
    msg_head.opcode = RX_SETUP;
    msg_head.can_id = CAN_ID;
    msg_head.nframes = 1;
    msg_head.ival1.tv_usec = CAN_PERIOD;
    msg_head.count = 0;
    msg_head.flags |= SETTIMER | STARTTIMER;

    struct iovec iov[1];
    struct can_frame frame;
    memset(&frame, 0, sizeof(frame));
    frame.can_id = CAN_ID;
    frame.can_dlc = CAN_DLC;
    iov[0].iov_base = &frame;
    iov[0].iov_len = sizeof(frame);

    struct bcm_msg bcm_msg;
    memset(&bcm_msg, 0, sizeof(bcm_msg));
    bcm_msg.msg_head = msg_head;
    bcm_msg.msg_iov = iov;
    bcm_msg.msg_iovlen = 1;

    if (ioctl(sock, BCM_SETTIMER, &bcm_msg) < 0) {
        perror("ioctl");
        exit(1);
    }

    while (1) {
        struct can_frame recv_frame;
        ssize_t nbytes = recv(sock, &recv_frame, sizeof(recv_frame), 0);
        if (nbytes < 0) {
            perror("recv");
            exit(1);
        }

        if (recv_frame.can_id == CAN_ID) {
            // 处理接收到的广播消息
            printf("Received broadcast message: %s\n", recv_frame.data);
        }
    }

    return 0;
}

该程序使用BCM模块向CAN总线发送一个周期为100ms的广播消息，消息ID为0x123，数据长度为8字节。在接收端，程序通过普通的SocketCAN接收函数recv来接收广播消息，并根据消息ID进行过滤。