广东金融学院锐捷客户端学习笔记

这几天与高中同学换宿舍住，来到广东金融学院学习，沮丧的是刚来到的时候我的电脑都没办法上网，原因在于学校的认证会绑定IP和mac地址，而网卡mac地址似乎是无法修改的，只能改系统储存的mac地址，然而这里的客户端会比较这俩地址，如果不一样就gg。

接下来就开始研究这里的锐捷认证客户端了，本来我以为这里的认证是这样的：先通过DHCP获取IP地址，然后认证服务器是某个IP标定的机器，然后通过tcp或者udp收发一些认证包，然而通过wireshark抓包，我发现并不是这样，是通过eap认证的 ：https://en.wikipedia.org/wiki/Extensible_Authentication_Protocol，这是数据链路层的协议，在这里就是用收发以太网帧的形式实现的，由于无聊，我决定尝试写一个程序模仿客户端认证，原本以为可以通过raw socket，然而看了一下msnd：https://msdn.microsoft.com/zh-cn/library/windows/desktop/ms740506(v=vs.85).aspx，并没有发现收发以太网帧的接口，于是改用winpcap，这个还有例程，期间遇到了一系列的问题，就不一一讲述了，感谢知乎上朋友的帮助：https://www.zhihu.com/question/51197299，然而最终并没能成功认证，虽然可以把帐号密码发过去，但是返回“请使用管理员指定客户端”，考虑到这种吃力不讨好的活，果断选择放弃。

下面是写的代码，其中md5部分代码来自网络，自己只是作了部分修改

头文件：

#ifndef MD5_H  
#define MD5_H  
   
typedef struct  
{  
    unsigned int count[2];  
    unsigned int state[4];  
    unsigned char buffer[64];     
}MD5_CTX;  
   
                           
#define F(x,y,z) ((x & y) | (~x & z))  
#define G(x,y,z) ((x & z) | (y & ~z))  
#define H(x,y,z) (x^y^z)  
#define I(x,y,z) (y ^ (x | ~z))  
#define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))  
#define FF(a,b,c,d,x,s,ac)           {           a += F(b,c,d) + x + ac;            a = ROTATE_LEFT(a,s);           a += b;             }  
#define GG(a,b,c,d,x,s,ac)             {             a += G(b,c,d) + x + ac;             a = ROTATE_LEFT(a,s);             a += b;             }  
#define HH(a,b,c,d,x,s,ac)            {             a += H(b,c,d) + x + ac;             a = ROTATE_LEFT(a,s);             a += b;             }  
#define II(a,b,c,d,x,s,ac)             {             a += I(b,c,d) + x + ac;             a = ROTATE_LEFT(a,s);             a += b;             }                                              
void MD5Init(MD5_CTX *context);  
void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);  
void MD5Final(MD5_CTX *context,unsigned char digest[16]);  
void MD5Transform(unsigned int state[4],unsigned char block[64]);  
void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);  
void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);  
   
#endif  

接收以太网帧的rvc.cpp，其中包含主函数：

#define HAVE_REMOTE
#include
#include "pcap.h"
#pragma comment(lib,"wpcap.lib")
#define MSGNUM 3
#define DB


#ifdef DB
#define dbg(...) printf(__VA_ARGS__)
#else 
#define dbg(...)
#endif
//此函数用于测试
int test();
//此函数用于把challenge值与密码进行md5运算后把结果嵌入in所指向的字符串
int makeMd5(char *in,char *challenge);
//此函数向fp指向的网卡发以太网帧，str_t为要发的字节所对应的十六进制字符串，比如"a16b"
void sendMsg(pcap_t *fp,char *str_t);
//此函数把字符串的值转化为unsigned char类型字节流，以便发送
int make_buf(u_char *buf,char *str_tran);
//此函数与make_buf作用相反，因为字节流没有结束符，所以标定长度
int unmake_buf(char*out,const u_char *in,int len){
for(int i = 0;iif((in[i]>>4)>=0&&(in[i]>>4)<10){
out[i*2] = (in[i]>>4)+'0';
}
else{
out[i*2] = (in[i]>>4)-10+'a';
}


if((in[i]%16)>=0&&(in[i]%16)<10){
out[i*2+1] = (in[i]%16)+'0';
}
else{
out[i*2+1] = (in[i]%16)-10+'a';
}
}
return 0;
}
//此函数从抓到的以太网帧中提取出challenge值
int getChallenge(char *challenge,const u_char *in){
int len = 16;
unmake_buf(challenge,in+24,len);
return 0;
}
//此函数从抓到的以太网帧中比较发送的目的地
int compareDst(const u_char *in,char *s){
u_char p[6];
int len = make_buf(p,s);
if(len != 6){
printf("error in compareDst\n");
return -1;
}
for(int j=0;j<6;j++){
if(in[j]!=p[j]){
dbg("compareDst:different in %d\n",j+1);
return 1;
}
}
return 0;
}
//此函数从抓到的以太网帧中比较发送的源地址
int compareSrc(const u_char *in,char *s){
u_char p[6];
int len = make_buf(p,s);
if(len != 6){
printf("error in compareSrc\n");
return -1;
}
for(int j=0;j<6;j++){
if(in[j+6]!=p[j]){
dbg("compareSrc:different in %d\n",j+1);
return 1;
}
}
return 0;
}


int main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
int inum;
int i=0;
pcap_t *adhandle;
int res;
char errbuf[PCAP_ERRBUF_SIZE];
struct tm ltime;
char timestr[16];
struct pcap_pkthdr *header;
const u_char *pkt_data;
u_char *pkt_data1;
time_t local_tv_sec;
FILE *store_msg_fp;
char *store_msg[MSGNUM];
test();
// makeMd5(store_msg[2],"c53e3c36da2084728897332fb2a4161a");
if(!(store_msg_fp = fopen("save.txt","r+"))){
printf("failed to open the file\n");
exit(-1);
}
for(int j=0;jdbg("before malloc in for\n");
store_msg[j] = (char *)malloc(2000*sizeof(char));
fscanf(store_msg_fp,"%s",store_msg[j]);
dbg("%d scanf file\n",j);
}
dbg("before fclose\n");
fclose(store_msg_fp);
    dbg("before pkt malloc\n");
pkt_data = (u_char *)malloc(10000*sizeof(u_char));
    /* Retrieve the device list on the local machine */
    if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
    {
        fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
        exit(1);
    }
    
    /* Print the list */
    for(d=alldevs; d; d=d->next)
    {
        printf("%d. %s", ++i, d->name);
        if (d->description)
            printf(" (%s)\n", d->description);
        else
            printf(" (No description available)\n");
    }
    
    if(i==0)
    {
        printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
        return -1;
    }
    
    printf("Enter the interface number (1-%d):",i);
    scanf_s("%d", &inum);
    
    if(inum < 1 || inum > i)
    {
        printf("\nInterface number out of range.\n");
        /* Free the device list */
        pcap_freealldevs(alldevs);
        return -1;
    }
    
    /* Jump to the selected adapter */
    for(d=alldevs, i=0; i< inum-1 ;d=d->next, i++);
    
    /* Open the device */
    if ( (adhandle= pcap_open(d->name,          // name of the device
                              65536,            // portion of the packet to capture. 
                                                // 65536 guarantees that the whole packet will be captured on all the link layers
                              PCAP_OPENFLAG_PROMISCUOUS,    // promiscuous mode
                              1000,             // read timeout
                              NULL,             // authentication on the remote machine
                              errbuf            // error buffer
                              ) ) == NULL)
    {
        fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n", d->name);
        /* Free the device list */
        pcap_freealldevs(alldevs);
        return -1;
    }
    
    printf("\nlistening on %s...\n", d->description);
    
    /* At this point, we don't need any more the device list. Free it */
    pcap_freealldevs(alldevs);
sendMsg(adhandle,store_msg[0]);
    /* Retrieve the packets */
    while((res = pcap_next_ex( adhandle, &header, &pkt_data)) >= 0){
        
        if(res == 0)
            /* Timeout elapsed */
            continue;
        
        /* convert the timestamp to readable format */
        local_tv_sec = header->ts.tv_sec;
        localtime_s(<ime, &local_tv_sec);
        strftime( timestr, sizeof timestr, "%H:%M:%S", <ime);
        
        printf("%s,%.6d len:%d:\n", timestr, header->ts.tv_usec, header->len);
int len = header->len;


dbg("before compare\n");
if((!compareDst(pkt_data,"f8a9630569d8"))&&(!compareSrc(pkt_data,"001aa978e4fe"))){
for(int j = 0;jprintf("%2x  ",pkt_data[j]);
}
printf("\n");
if(len>18){
if(pkt_data[18]==1){
printf("now recieve the request packet!\n");
if(pkt_data[19]==1){
printf("request identity!\n");
sendMsg(adhandle,store_msg[1]);
printf("identity send!\n");
}
else if(pkt_data[19]==2){
printf("request MD5-Challenge!\n");
char challenge[33]={0};
dbg("before getChallenge\n");
getChallenge(challenge,pkt_data);
dbg("challenge is :%s\n",challenge);
dbg("before makeMd5\n");
makeMd5(store_msg[2],challenge);
dbg("before sendMsg\n");
sendMsg(adhandle,store_msg[2]);
printf("MD5-Challenge send!\n");
}
}
else if(pkt_data[18]==3){
printf("now log success!\n");
}
else if(pkt_data[18]==4){
printf("now log failed! I am crying!!! My heart is HURT!!!\n");
scanf("%d",res);
}
}
}
printf("\n");
    }
    
    if(res == -1){
        printf("Error reading the packets: %s\n", pcap_geterr(adhandle));
        return -1;
    }
    return 0;
}

md5.cpp：

#include  
#include "md5.h"  
   
unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  
                         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  
                         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  
                         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};  
                           
void MD5Init(MD5_CTX *context)  
{  
     context->count[0] = 0;  
     context->count[1] = 0;  
     context->state[0] = 0x67452301;  
     context->state[1] = 0xEFCDAB89;  
     context->state[2] = 0x98BADCFE;  
     context->state[3] = 0x10325476;  
}  
void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen)  
{  
    unsigned int i = 0,index = 0,partlen = 0;  
    index = (context->count[0] >> 3) & 0x3F;  
    partlen = 64 - index;  
    context->count[0] += inputlen << 3;  
    if(context->count[0] < (inputlen << 3))  
       context->count[1]++;  
    context->count[1] += inputlen >> 29;  
      
    if(inputlen >= partlen)  
    {  
       memcpy(&context->buffer[index],input,partlen);  
       MD5Transform(context->state,context->buffer);  
       for(i = partlen;i+64 <= inputlen;i+=64)  
           MD5Transform(context->state,&input[i]);  
       index = 0;          
    }    
    else  
    {  
        i = 0;  
    }  
    memcpy(&context->buffer[index],&input[i],inputlen-i);  
}  
void MD5Final(MD5_CTX *context,unsigned char digest[16])  
{  
    unsigned int index = 0,padlen = 0;  
    unsigned char bits[8];  
    index = (context->count[0] >> 3) & 0x3F;  
    padlen = (index < 56)?(56-index):(120-index);  
    MD5Encode(bits,context->count,8);  
    MD5Update(context,PADDING,padlen);  
    MD5Update(context,bits,8);  
    MD5Encode(digest,context->state,16);  
}  
void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len)  
{  
    unsigned int i = 0,j = 0;  
    while(j < len)  
    {  
         output[j] = input[i] & 0xFF;    
         output[j+1] = (input[i] >> 8) & 0xFF;  
         output[j+2] = (input[i] >> 16) & 0xFF;  
         output[j+3] = (input[i] >> 24) & 0xFF;  
         i++;  
         j+=4;  
    }  
}  
void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len)  
{  
     unsigned int i = 0,j = 0;  
     while(j < len)  
     {  
           output[i] = (input[j]) |  
                       (input[j+1] << 8) |  
                       (input[j+2] << 16) |  
                       (input[j+3] << 24);  
           i++;  
           j+=4;   
     }  
}  
void MD5Transform(unsigned int state[4],unsigned char block[64])  
{  
     unsigned int a = state[0];  
     unsigned int b = state[1];  
     unsigned int c = state[2];  
     unsigned int d = state[3];  
     unsigned int x[64];  
     MD5Decode(x,block,64);  
     FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */  
 FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */  
 FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */  
 FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */  
 FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */  
 FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */  
 FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */  
 FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */  
 FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */  
 FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */  
 FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */  
 FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */  
 FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */  
 FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */  
 FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */  
 FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */  
   
 /* Round 2 */  
 GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */  
 GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */  
 GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */  
 GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */  
 GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */  
 GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */  
 GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */  
 GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */  
 GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */  
 GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */  
 GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */  
 GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */  
 GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */  
 GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */  
 GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */  
 GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */  
   
 /* Round 3 */  
 HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */  
 HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */  
 HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */  
 HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */  
 HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */  
 HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */  
 HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */  
 HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */  
 HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */  
 HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */  
 HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */  
 HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */  
 HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */  
 HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */  
 HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */  
 HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */  
   
 /* Round 4 */  
 II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */  
 II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */  
 II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */  
 II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */  
 II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */  
 II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */  
 II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */  
 II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */  
 II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */  
 II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */  
 II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */  
 II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */  
 II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */  
 II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */  
 II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */  
 II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */  
     state[0] += a;  
     state[1] += b;  
     state[2] += c;  
     state[3] += d;  
}  

caculate_md5.cpp:

#include  
#include
#include


#include "md5.h" 
#define DB
#ifdef DB
#define dbg(...) printf(__VA_ARGS__)
#else 
#define dbg(...)
#endif


#define PASSSTR "02383838383838"
 
  
static int make_buf(unsigned char *buf,char *str_tran){
int i;
dbg("enter make_buf...\n");
for(i=0;str_tran[i]!=0;i+=2){
if(str_tran[i]>='0'&&str_tran[i]<='9'){
buf[i/2] = (str_tran[i] - '0')<<4;
}
else{
buf[i/2] = (str_tran[i] - 'a'+10)<<4;
}
if(str_tran[i+1]>='0'&&str_tran[i+1]<='9'){
buf[i/2] += str_tran[i+1] - '0';
}
else{
buf[i/2] += str_tran[i+1] - 'a'+10;
}
}
dbg("leave make_buf...\n");
return i/2;
}




int caculate_md5(char *wait_make)  
{  
    int i;  
int len;
unsigned char decrypt[16];
unsigned char encrypt[25]={0};//21232f297a57a5a743894a0e4a801fc3  
len = make_buf(encrypt,wait_make);
    MD5_CTX md5;  
    MD5Init(&md5);                
    MD5Update(&md5,encrypt,len);  
    MD5Final(&md5,decrypt);     
    printf("加密前:\n",encrypt);  
for(int j=0;jprintf("%2x",encrypt[j]);
}
FILE *p;
p = fopen("tmp_store_md5.txt","w+");
    for(i=0;i<16;i++)  
    {  
        fprintf(p,"%02x",decrypt[i]);  
    }  
printf("\n");
    fclose(p);
      
    return 0;  
}  


int makeMd5(char *in,char *challenge){
char *wait_make;
dbg("before open malloc in makeMd5\n");
wait_make = (char*)malloc(2000*sizeof(char));
memset(wait_make,0,2000*sizeof(char));
strcpy(wait_make,PASSSTR);
dbg("before strcat in makeMd5\n");
dbg("wait_make is :%s\n",wait_make);
dbg("challenge is :%s\n",challenge);
// int len_wa = strlen(wait_make);
// int len_ch = strlen(challenge);
//for(int j = len_wa;j<(len_ch+len_wa);j++){
// wait_make[j] = challenge[j-len_wa];
//}
strcat(wait_make,challenge);
dbg("wait_make after for is :%s\n",wait_make);
dbg("after strcat in makeMd5\n");
if(strlen(wait_make)!=46){
printf("bug:error in makeMd5:%d  !",strlen(wait_make));
scanf("%s",challenge);
exit(-1);
}
//wait_make = "02383838383838c53e3c36da2084728897332fb2a4161a";
dbg("before caculate_md5:wait_make:%s\n",wait_make);
caculate_md5(wait_make);

dbg("before open tmp_store_md5\n");
FILE *store;
if(!(store = fopen("tmp_store_md5.txt","r+"))){
printf("bug:error in makeMd5 open file !");
scanf("%s",challenge);
exit(-1);
}
dbg("before scanf in makeMd5\n");
fscanf(store,"%s",wait_make);
dbg("wait_make after fscan is :%s\n",wait_make);
memcpy(in+48,wait_make,32);
/*if(make_buf(in+48,wait_make)!=16){
printf("bug:error in makeMd5 make_buf !");
scanf("%s",challenge);
exit(-1);
}*/
free(wait_make);
return 0;
}
int test(){
int i;
char wait_make[100];
caculate_md5("023838383838384ab6f237a0d63916b5487da507f0c172");
FILE *store;
if(!(store = fopen("tmp_store_md5.txt","r+"))){
printf("bug:error in makeMd5 open file !");
scanf("%d",i);
exit(-1);
}
dbg("before scanf in makeMd5\n");
fscanf(store,"%s",wait_make);
dbg("wait_make after fscan is :%s\n",wait_make);
return 0;
}

发送以太网帧send.cpp:

#define HAVE_REMOTE
#include "pcap.h"
#include


#include
#include
#pragma comment(lib,"wpcap.lib")


#define DB


#ifdef DB
#define dbg(...) printf(__VA_ARGS__)
#else 
#define dbg(...)
#endif


int make_buf(u_char *buf,char *str_tran){
int i;
dbg("enter make_buf...\n");
for(i=0;str_tran[i]!=0;i+=2){
if(str_tran[i]>='0'&&str_tran[i]<='9'){
buf[i/2] = (str_tran[i] - '0')<<4;
}
else{
buf[i/2] = (str_tran[i] - 'a'+10)<<4;
}
if(str_tran[i+1]>='0'&&str_tran[i+1]<='9'){
buf[i/2] += str_tran[i+1] - '0';
}
else{
buf[i/2] += str_tran[i+1] - 'a'+10;
}
}
dbg("leave make_buf...\n");
return i/2;
}


void sendMsg(pcap_t *fp,char *str_t)
{


//FILE *p=NULL;
char errbuf[PCAP_ERRBUF_SIZE];
u_char packet[1000] = {0};
int len = 0;
// char str_t[2000] = {0};
// string str_t;
//int i;
//if((p=fopen("save.txt","r"))==NULL){
 //       dbg("failed to open file\n");
// exit(1);
//}
    /* Check the validity of the command line */
    
    /* Open the output device */
    //if ( (fp= pcap_open(st,            // name of the device
    //                    100,                // portion of the packet to capture (only the first 100 bytes)
    //                    PCAP_OPENFLAG_PROMISCUOUS,  // promiscuous mode
    //                    1000,               // read timeout
    //                    NULL,               // authentication on the remote machine
    //                    errbuf              // error buffer
    //                    ) ) == NULL)
    //{
    //    fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n",st);
    //    return;
    //}

    /* Supposing to be on ethernet, set mac destination to 1:1:1:1:1:1 */
//for(int j=0;j<3;j++){
//fscanf(p,"%s",str_t);
len = make_buf(packet,str_t);
dbg("the len of buf is %d\n",len);
if (pcap_sendpacket(fp, packet, len /* size */) != 0){
  fprintf(stderr,"\nError sending the packet in make_buf: %s\n", pcap_geterr(fp));
       return;
    }
//}
printf("send successfully!\n");
//fclose(p);
    return;
}




void test()
{
    pcap_if_t *alldevs;
    /*struct pcap_if_t{
    pcap_if_t *next;
    char *name;
    char *description;
    pcap_addr *addresses;
    U_int falgs;
    }
    */
    pcap_if_t *d;
    int i=0;
    char errbuf[2000];
    /* Retrieve the device list */
    if (pcap_findalldevs(&alldevs, errbuf) == -1)//返回网卡列表，alldevs指向表头
    {
        fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
        exit(1);
    }
    /* Print the list */
    for(d=alldevs;d;d=d->next)
    {
        printf("%d. %s", ++i, d->name);
        if (d->description){
printf(" (%s)\n", d->description);
if(i==3){
// sendMsg(d->name,"666");
}
}
        else printf(" (No description available)\n");


    }
    if(i==0)
    {


        printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
        return;
    }
    /* We don't need any more the device list. Free it */
    pcap_freealldevs(alldevs);
}