Linux ioctl的简单应用

1.检测接口的 inet_addr,netmask,broad_addr

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <net/if.h>



int main(int argc, char **argv)
{
    struct sockaddr_in *addr;
    struct ifreq ifr;
    char *name, *address;
    int sockfd = -1;

    if (argc != 2) {
        printf("usage : %s interface \n", argv[0]);
        exit(-1);
    } else
        name = argv[1];

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    strncpy(ifr.ifr_name, name, IFNAMSIZ - 1);
    if (ioctl(sockfd, SIOCGIFADDR, &ifr) == -1) {
        perror("ioctl error\n");
        exit(1);
    }

    addr = (struct sockaddr_in *)&(ifr.ifr_addr);
    address = inet_ntoa(addr->sin_addr);
    printf("inet addr: %s\n", address);
    if (ioctl(sockfd, SIOCGIFBRDADDR, &ifr) == -1) {
        perror("ioctl error\n");
        exit(1);
    }

    addr = (struct sockaddr_in *)&ifr.ifr_broadaddr;
    address = inet_ntoa(addr->sin_addr);
    printf("broad addr: %s\n", address);
    if (ioctl(sockfd, SIOCGIFNETMASK, &ifr) == -1) {
        perror("ioctl error\n");
        exit(1);
    }

    addr = (struct sockaddr_in *)&ifr.ifr_addr;
    address = inet_ntoa(addr->sin_addr);
    printf("inet mask: %s\n", address);

    close(sockfd);

    exit(0);
}

2.检查接口的物理连接是否正常

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>



typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned char u8;


int detect_mii(int skfd, char *ifname)
{
    struct ifreq ifr;
    u16 *data, mii_val;
    unsigned phy_id;

    /* Get the vitals from the interface. */
    strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
    if (ioctl(skfd, SIOCGMIIPHY, &ifr) < 0) {
        fprintf(stderr, "SIOCGMIIPHY on %s failed: %s\n", ifname,
                strerror(errno));
        close(skfd);

        return 2;
    }

    data = (u16 *) (&ifr.ifr_data);
    phy_id = data[0];
    data[1] = 1;
    if (ioctl(skfd, SIOCGMIIREG, &ifr) < 0) {
        fprintf(stderr, "SIOCGMIIREG on %s failed: %s\n", ifr.ifr_name,
                strerror(errno));
        close(skfd);

        return 2;
    }
    mii_val = data[3];

    return (((mii_val & 0x0016) == 0x0004) ? 0 : 1);
}

int detect_ethtool(int skfd, char *ifname)
{
    struct ifreq ifr;
    struct ethtool_value edata;

    memset(&ifr, 0, sizeof(ifr));
    edata.cmd = ETHTOOL_GLINK;
    strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
    ifr.ifr_data = (char *)&edata;
    if (ioctl(skfd, SIOCETHTOOL, &ifr) == -1) {
        printf("ETHTOOL_GLINK failed: %s\n", strerror(errno));
        return 2;
    }

    return (edata.data ? 0 : 1);
}

int main(int argc, char **argv)
{
    int skfd = -1;
    char *ifname;
    int retval;

    if (argv[1])
        ifname = argv[1];
    else
        ifname = "eth0";

    /* Open a socket. */
    if ((skfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        printf("socket error\n");
        exit(-1);
    }
    retval = detect_ethtool(skfd, ifname);
    if (retval == 2)
        retval = detect_mii(skfd, ifname);
    close(skfd);

    if (retval == 2)
        printf("Could not determine status\n");
    else if (retval == 1)
        printf("Link down\n");
    else if (retval == 0)
        printf("Link up\n");

    return 0;
}

3.检测接口物理链接版本二

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <net/if.h>
#include <linux/sockios.h>
#include <sys/ioctl.h>

#define LINKTEST_GLINK 0x0000000a

struct linktest_value {
    unsigned int cmd;
    unsigned int data;
};

static void usage(const char *pname)
{
    fprintf(stderr, "usage: %s \n", pname);
    fprintf(stderr, "returns: \n");
    fprintf(stderr, "\t 0: link detected\n");
    fprintf(stderr, "\t%d: %s\n", ENODEV, strerror(ENODEV));
    fprintf(stderr, "\t%d: %s\n", ENONET, strerror(ENONET));
    fprintf(stderr, "\t%d: %s\n", EOPNOTSUPP, strerror(EOPNOTSUPP));

    exit(EXIT_FAILURE);
}

static int linktest(const char *devname)
{
    struct ifreq ifr;
    struct linktest_value edata;
    int fd;

    /* setup our control structures. */
    memset(&ifr, 0, sizeof(ifr));
    strcpy(ifr.ifr_name, devname);
    /* open control socket. */
    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (fd < 0) {
        return -ECOMM;
    }
    errno = 0;
    edata.cmd = LINKTEST_GLINK;
    ifr.ifr_data = (caddr_t) & edata;
    if (!ioctl(fd, SIOCETHTOOL, &ifr)) {
        if (edata.data) {
            fprintf(stdout, "link detected on %s\n", devname);
            return 0;
        } else {
            errno = ENONET;
        }
    }
    perror("linktest");

    return errno;
}

int main(int argc, char *argv[])
{
    if (argc != 2) {
        usage(argv[0]);
    }

    return linktest(argv[1]);
}

4.调节音量

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>
#include <stdio.h>
#include <unistd.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>

#define  BASE_VALUE 257

int main(int argc, char *argv[])
{
    int mixer_fd = 0;
    char *names[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_LABELS;
    int value, i;

    if (argc < 3) {
        printf("\nusage:%s dev_no.[0..24] value[0..100]\n\n", argv[0]);
        printf("eg. %s 0 100\n", argv[0]);
        printf("    will change the volume to MAX volume.\n\n");
        printf("The dev_no. are as below:\n");
        for (i = 0; i < SOUND_MIXER_NRDEVICES; i++) {
            if (i % 3 == 0)
                printf("\n");
            printf("%s:%d\t\t", names[i], i);
        }
        printf("\n\n");

        exit(1);
    }

    if ((mixer_fd = open("/dev/mixer", O_RDWR))) {
        printf("Mixer opened successfully,working...\n");
        value = BASE_VALUE * atoi(argv[2]);
        if (ioctl(mixer_fd, MIXER_WRITE(atoi(argv[1])), &value) == 0)
            printf("successfully.....");
        else
            printf("unsuccessfully.....");
        printf("done.\n");
    } else
        printf("can't open /dev/mixer error....\n");

    exit(0);
}