iwconfig wlan0 获取"AP address"源码

以下为自己实现：

源码的本质其实也就是调用了iw_get_ext()里的ioctl()

    int skfd1 = 0;

    skfd1 = iw_sockets_open();
    if(skfd1 < 0)
    {
        printf("%s:%d Open socket error!\n", __FILE__, __LINE__);
    iw_sockets_close(skfd1);
    exit(-1);
    }

   /*Get AP address*/
    int i;

    ioctl(fd,SIOCGIWAP,&wrq);
    printf("wrq.u.ap_addr:");
    unsigned char *APaddr = (unsigned char *)wrq.u.ap_addr.sa_data;
    for(i = 0;i < 6;i++)
    {
    printf("%02x",(int)APaddr[i]);
    if(i != 5)
     printf("%c",':');
    else
    printf("\n");
    }

/* Get ESSID */

   char buffer[32];
    memset(buffer,0,32);
    wreq->u.essid.pointer = buffer;
    wreq->u.essid.length = 32;
    ioctl(skfd1,SIOCGIWESSID,wreq);
    printf("ESSID:%s\n",(char *)wreq->u.essid.pointer);

    if(strcmp((char *)wrq.u.essid.pointer,"") == 0)
    {
    return -1;
    }

iwconfig 源码： (iwconfig wlan0)

typedef struct wireless_config
{
  char        name[IFNAMSIZ + 1];    /* Wireless/protocol name */
  int        has_nwid;
  iwparam    nwid;            /* Network ID */
  int        has_freq;
  double    freq;            /* Frequency/channel */
  int        freq_flags;
  int        has_key;
  unsigned char    key[IW_ENCODING_TOKEN_MAX];    /* Encoding key used */
  int        key_size;        /* Number of bytes */
  int        key_flags;        /* Various flags */
  int        has_essid;
  int        essid_on;
  char        essid[IW_ESSID_MAX_SIZE + 1];    /* ESSID (extended network) */
  int        has_mode;
  int        mode;            /* Operation mode */
} wireless_config;

typedef struct wireless_info
{
    struct wireless_config    b;    /* Basic information */

    int        has_sens;
    iwparam    sens;            /* sensitivity */
    int        has_nickname;
    char        nickname[IW_ESSID_MAX_SIZE + 1]; /* NickName */
    int        has_ap_addr;
    sockaddr    ap_addr;        /* Access point address */
    int        has_bitrate;
    iwparam    bitrate;        /* Bit rate in bps */
    int        has_rts;
    iwparam    rts;            /* RTS threshold in bytes */
    int        has_frag;
    iwparam    frag;            /* Fragmentation threshold in bytes */
    int        has_power;
    iwparam    power;            /* Power management parameters */
    int        has_txpower;
    iwparam    txpower;        /* Transmit Power in dBm */
    int        has_retry;
    iwparam    retry;            /* Retry limit or lifetime */

    /* Stats */
    iwstats    stats;
    int        has_stats;
    iwrange    range;
    int        has_range;

    /* Auth params for WPA/802.1x/802.11i */
    int        auth_key_mgmt;
    int        has_auth_key_mgmt;
    int        auth_cipher_pairwise;
    int        has_auth_cipher_pairwise;
    int        auth_cipher_group;
    int        has_auth_cipher_group;
} wireless_info;

struct sockaddr {
    sa_family_t    sa_family;    /* address family, AF_xxx    */
    char        sa_data[14];    /* 14 bytes of protocol address    */
};

union    iwreq_data
{
    /* Config - generic */
    char        name[IFNAMSIZ];
    /* Name : used to verify the presence of  wireless extensions.
     * Name of the protocol/provider... */

    struct iw_point    essid;        /* Extended network name */
    struct iw_param    nwid;        /* network id (or domain - the cell) */
    struct iw_freq    freq;        /* frequency or channel :
                     * 0-1000 = channel
                     * > 1000 = frequency in Hz */

    struct iw_param    sens;        /* signal level threshold */
    struct iw_param    bitrate;    /* default bit rate */
    struct iw_param    txpower;    /* default transmit power */
    struct iw_param    rts;        /* RTS threshold threshold */
    struct iw_param    frag;        /* Fragmentation threshold */
    __u32        mode;        /* Operation mode */
    struct iw_param    retry;        /* Retry limits & lifetime */

    struct iw_point    encoding;    /* Encoding stuff : tokens */
    struct iw_param    power;        /* PM duration/timeout */
    struct iw_quality qual;        /* Quality part of statistics */

    struct sockaddr    ap_addr;    /* Access point address */
    struct sockaddr    addr;        /* Destination address (hw/mac) */

    struct iw_param    param;        /* Other small parameters */
    struct iw_point    data;        /* Other large parameters */
};

struct    iwreq
{
    union
    {
        char    ifrn_name[IFNAMSIZ];    /* if name, e.g. "eth0" */
    } ifr_ifrn;

    /* Data part (defined just above) */
    union    iwreq_data    u;
};

/*
 * Display an Ethernet address in readable format.
 */
void iw_ether_ntop(const struct ether_addr *eth,char *buf)
{
    sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X",
            eth->ether_addr_octet[0], eth->ether_addr_octet[1],
            eth->ether_addr_octet[2], eth->ether_addr_octet[3],
            eth->ether_addr_octet[4], eth->ether_addr_octet[5]);
}

char *iw_sawap_ntop(const struct sockaddr *sap,char *buf)
{
    const struct ether_addr ether_zero = {{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }};
    const struct ether_addr ether_bcast = {{ 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }};
    const struct ether_addr ether_hack = {{ 0x44, 0x44, 0x44, 0x44, 0x44, 0x44 }};
    const struct ether_addr * ether_wap = (const struct ether_addr *) sap->sa_data;

    if(!iw_ether_cmp(ether_wap, &ether_zero))
        sprintf(buf, "Not-Associated");
    else
        //............
        iw_ether_ntop(ether_wap, buf);
    return(buf);
}

/*------------------------------------------------------------------*/
/*
 * Wrapper to extract some Wireless Parameter out of the driver
 */
static inline int iw_get_ext(int            skfd,        /* Socket to the kernel */
        const char *        ifname,        /* Device name */
        int            request,    /* WE ID */
        struct iwreq *    pwrq)        /* Fixed part of the request */
{
    /* Set device name */
    strncpy(pwrq->ifr_name, ifname, IFNAMSIZ);
    /* Do the request */
    return(ioctl(skfd, request, pwrq));
}

int iw_get_basic_config(int    skfd,const char *ifname,wireless_config *info)
{
    struct iwreq        wrq;

    memset((char *) info, 0, sizeof(struct wireless_config));
    if(iw_get_ext(skfd, ifname, SIOCGIWNAME, &wrq) < 0)
    {
    }
    /* Get wireless name */
    /* Get network ID */
    /* Get frequency / channel */
    /* Get encryption information */
    /* Get ESSID */
    //.............

}

/*
 * Print on the screen in a neat fashion all the info we have collected
 * on a device.
 */
static void display_info(struct wireless_info *info,char *    ifname)
{
    /* Display the address of the current Access Point */
    if(info->has_ap_addr)
    {
        /* A bit of clever formatting */
        if(tokens > 8)
        {
            printf("\n          ");
            tokens = 0;
        }
        tokens +=6;

        /* Oups ! No Access Point in Ad-Hoc mode */
        if((info->b.has_mode) && (info->b.mode == IW_MODE_ADHOC))
            printf("Cell:");
        else
            printf("Access Point:");
        printf(" %s   ", iw_sawap_ntop(&info->ap_addr, buffer));
    }
}

static int get_info(int    skfd,char *ifname,struct wireless_info *info)
{
    struct iwreq    wrq;

    memset((char *) info, 0, sizeof(struct wireless_info));

    /* Get basic information */
    if(iw_get_basic_config(skfd, ifname, &(info->b)) < 0)
    {
    }

     /* Get AP address */
    if(iw_get_ext(skfd, ifname, SIOCGIWAP, &wrq) >= 0)
    {
        info->has_ap_addr = 1;
        memcpy(&(info->ap_addr), &(wrq.u.ap_addr), sizeof (sockaddr));
    }


static int print_info(int    skfd,char *ifname,char *args[],int count)
{
    struct wireless_info    info;
    int    rc;

    /* Avoid "Unused parameter" warning */
    args = args; count = count;

    rc = get_info(skfd, ifname, &info);
    switch(rc)
    {
    case 0:    /* Success */
        /* Display it ! */
        display_info(&info, ifname);
        break;

        return(rc);
    }

// iwconfig waln0
int main(int argc,char **argv)
    {
        int skfd;        /* generic raw socket desc.    */

        /* Create a channel to the NET kernel. */
        if((skfd = iw_sockets_open()) < 0)
        {
            perror("socket");
            exit(-1);
        }
        /* The device name must be the first argument */
        if(argc == 2)
            print_info(skfd, argv[1], NULL, 0);

        /* Close the socket. */
        iw_sockets_close(skfd);
    }

/* -------------------------- IOCTL LIST -------------------------- */

#define SIOCGIWNAME    0x8B01        /* get name == wireless protocol */

#define SIOCSIWFREQ    0x8B04        /* set channel/frequency (Hz) */
#define SIOCGIWFREQ    0x8B05        /* get channel/frequency (Hz) */
#define SIOCSIWMODE    0x8B06        /* set operation mode */
#define SIOCGIWMODE    0x8B07        /* get operation mode */

#define SIOCSIWAP    0x8B14        /* set access point MAC addresses */
#define SIOCGIWAP    0x8B15        /* get access point MAC addresses */

#define SIOCSIWESSID    0x8B1A        /* set ESSID (network name) */
#define SIOCGIWESSID    0x8B1B        /* get ESSID */

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