用winpcap是否捕获不到PAP、LCP协议包?

用winpcap是否捕获不到PAP、LCP协议包(pppoe)。我的代码如下:
typedef struct pppoe
{
unsigned char vertype;
unsigned char code;
unsigned short session_id;
unsigned short len;
unsigned short pap;
}PPPOE,*PPPPOE;

typedef struct ethdr
{

    unsigned char   eh_dst[6];
    unsigned char   eh_src[6];
    unsigned short  eh_type;
}ETHDR,*PETHDR;

if(eth->eh_type==htons(0x8864)){
if(pppoe->pap==htons(0xC023)){
PrintPackets(pPacket);
}
if(pppoe->pap==htons(0xC025)){
PrintPackets(pPacket);
}
if(pppoe->pap==htons(0xC223)){
PrintPackets(pPacket);
}
if(pppoe->pap==htons(0xC021)){
PrintPackets(pPacket);
}
if(pppoe->pap==htons(0x8021)){
PrintPackets(pPacket);
}

}
可是在在用adsl拨号直到登录成功，没有任何显示

没有人知道吗

up