libpcap和无线信号捕获

我正在尝试编写一个c++应用程序（linux），它将捕获无线数据包以及相关的信号强度（以dBm为单位）。捕获部分很容易，但问题是我找不到任何关于如何获得每个数据包的信号强度的文档。

它是页眉的一部分吗？

到目前为止，我拥有的是：

printf("Device: %sn", dev);
printf("Number of packets: %dn", num_packets);
printf("Filter expression: %sn", filter_exp);
/* open capture device */
    pcap_t *handler = pcap_create("wlan0", errbuf);
    if (handler == NULL)
    {
        exit(-1);
    }
    if(pcap_set_rfmon(handler,1)==0 )
    {
        printf("monitor mode enabledn");
    }
    pcap_set_snaplen(handler, 2048);  // Set the snapshot length to 2048
    pcap_set_promisc(handler, 0); // Turn promiscuous mode off
    pcap_set_timeout(handler, 512); // Set the timeout to 512 milliseconds
    int status = pcap_activate(handler);

/* now we can set our callback function */
pcap_loop(handle, num_packets, got_packet, NULL);

这是got_packet代码：

/* define ethernet header */
ethernet = (struct sniff_ethernet*)(packet);
/* define/compute ip header offset */
ip = (struct sniff_ip*)(packet + SIZE_ETHERNET);
size_ip = IP_HL(ip)*4;
if (size_ip < 20) {
    printf("   * Invalid IP header length: %u bytesn", size_ip);
    return;
}
/* print source and destination IP addresses */
printf("       From: %sn", inet_ntoa(ip->ip_src));
printf("         To: %sn", inet_ntoa(ip->ip_dst));
/* determine protocol */    
switch(ip->ip_p) {
    case IPPROTO_TCP:
        printf("   Protocol: TCPn");
        break;
    case IPPROTO_UDP:
        printf("   Protocol: UDPn");
        return;
    case IPPROTO_ICMP:
        printf("   Protocol: ICMPn");
        return;
    case IPPROTO_IP:
        printf("   Protocol: IPn");
        return;
    default:
        printf("   Protocol: unknownn");
        return;
}
/* define/compute tcp header offset */
tcp = (struct sniff_tcp*)(packet + SIZE_ETHERNET + size_ip);
size_tcp = TH_OFF(tcp)*4;
if (size_tcp < 20) {
    printf("   * Invalid TCP header length: %u bytesn", size_tcp);
    return;
}
printf("   Src port: %dn", ntohs(tcp->th_sport));
printf("   Dst port: %dn", ntohs(tcp->th_dport));
/* define/compute tcp payload (segment) offset */
payload = (char *)(packet + SIZE_ETHERNET + size_ip + size_tcp);
/* compute tcp payload (segment) size */
size_payload = ntohs(ip->ip_len) - (size_ip + size_tcp);
/*
 * Print payload data; it might be binary, so don't just
 * treat it as a string.
 */
if (size_payload > 0) {
    printf("   Payload (%d bytes):n", size_payload);
    //print_payload(payload, size_payload);
}

任何帮助都将不胜感激。

更新：/***************/以下是最新消息：因此，根据我的研究，正如盖伊·斯科特所提到的，我在寻找错误的信息。我需要查看无线数据包，而不是加载以太网数据包。这是更新后的代码：

 pcap_set_snaplen(handle, 2048);  // Set the snapshot length to 2048
    pcap_set_promisc(handle, 1);     // Turn promiscuous mode off
    pcap_set_timeout(handle, 512);   // Set the timeout to 512 milliseconds
    int status = pcap_activate(handle);
    if(pcap_set_datalink(handle, DLT_IEEE802_11_RADIO) == -1) {
        printf("Couldn't set datalink type %s: %sn", device, pcap_geterr(handle));
    }

所以现在的问题是解析数据包，这似乎是一个相当困难的问题。我对源地址、目的地地址和相关信号等感兴趣。我不知道如何匹配和加载数据包中的数据，并将其匹配到无线映射结构。

struct ieee80211_radiotap_header {
u_int8_t    it_version; /* set to 0 */
u_int8_t    it_pad;
u_int16_t   it_len; /* entire length */
u_int32_t   it_present; /* fields present */
} __attribute__((__packed__));
/* Presence bits */
#define RADIOTAP_TSFT   0
#define RADIOTAP_FLAGS  1
#define RADIOTAP_RATE   2
#define RADIOTAP_CHANNEL    3
#define RADIOTAP_FHSS   4
#define RADIOTAP_ANTENNA_SIGNAL 5
#define RADIOTAP_ANTENNA_NOISE  6
#define RADIOTAP_LOCK_QUALITY   7
#define RADIOTAP_TX_ATTENUATION 8
#define RADIOTAP_DB_TX_ATTENUATION  9
#define RADIOTAP_DBM_TX_POWER   10
#define RADIOTAP_ANTENNA    11
#define RADIOTAP_DB_ANTENNA_SIGNAL  12
void process_packet (u_char * args, const struct pcap_pkthdr *header, const u_char * packet)
{
    struct ieee80211_radiotap_header *packet_header = (struct ieee80211_radiotap_header *) header;
    // This is where I am stuck

有人能告诉我，一旦我捕获了数据包，我如何从中提取上述值吗？

感谢