小编ben*_*iga的帖子

#include <stdio.h>
#include <stdlib.h>
#include <pcap.h>

#define BUFFER_SIZE 65535

char errbuf[PCAP_ERRBUF_SIZE];

int main(int argc, char **argv)
{
    int d;
    pcap_if_t *alldevsp;
    pcap_t *pkt_handle;

    if((pcap_findalldevs(&alldevsp,errbuf))==-1)
    {
        printf("findalldevices: %s\n",errbuf);
        exit(1);
    }
    printf("Availabel network devices are\n");
    pcap_if_t *temp = alldevsp;
    while((temp)!=NULL)
    {
        printf("%s: %s\n",(temp)->name,(temp)->description);
        (temp)=(temp)->next;
    }
    pcap_freealldevs(alldevsp);

    pkt_handle = pcap_create("wlan1",errbuf);
    if(pkt_handle==NULL)
    {
        printf("create: %s\n",errbuf);
        exit(1);
    }


    if((pcap_set_rfmon(pkt_handle, 1))!=0)
    {
        printf("Monitor mode could not be set\n");
        exit(1);
    }

    if((pcap_set_buffer_size(pkt_handle, BUFFER_SIZE))!=0)
        {
        printf("ERROR\n");
        exit(1);
    }

    if((d=(pcap_activate(pkt_handle)))!=0)
    {
        if(d==PCAP_ERROR_RFMON_NOTSUP)
            printf("%d : PCAP_ERROR_RFMON_NOTSUP\n",d);
        if(d==PCAP_WARNING)
            printf("%d : PCAP_WARNING\n",d); …

以下代码是否正确计算无线802.11帧的FCS值？
因为以下代码生成的值与wireshark显示的值不匹配.

const uint32_t crctable[] = {
   0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
   0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L,
   0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L,
   0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L,
   0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
   0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
   0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL,
   0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL,
   0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L,
   0x7807c9a2L, …

以下是QoS数据的FC字段的位格式:

00|01|0001  01000010

前2位表示版本,下2位表示类型,下4位子类型,ToDS = 0,FromDS = 1,保护位= 1.

那么,上面的数据以什么顺序通过界面发送？(即从左到右或从右到左)

我看到wireshark将数据捕获为" 8842 "(在显示原始数据包数据的最后一段).

但是,如果我编写以下代码来打印FC字段数据:

struct mgmt_header_t {
    u_int16_t    fc;          /* 2 bytes */
    u_int16_t    duration;    /* 2 bytes */
    u_int8_t     addr1[6];    /* 6 bytes */  
    u_int8_t     addr2[6];    /* 6 bytes */  
    u_int8_t     addr3[6];    /* 6 bytes */  
    u_int16_t    seq_ctrl;    /* 2 bytes */
};
void my_callback(u_char *args, const struct pcap_pkthdr *header, const u_char *packet)
{
    int radiotapheader_length = (unsigned short int)(*(packet+2));
    struct mgmt_header_t *mac_header = (struct mgmt_header_t *)  (packet+radiotapheader_length);
    printf("FC …