ipfilter数据包不全的问题

我做了一个Ipfilter的驱动程序，我想拦截受邮件时收到的所有数据包，并把他显示出来。但是，我发现不能拦所有的数据包，下面是我拦截的代码：
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if( iph->ipProtocol == 6 )
{
tcph=(TCPHeader *)Packet;
port = ntohs( tcph->sourcePort );
cbSize = PacketLength - sizeof(TCPHeader);
if( port == 110 )
{
dprintf("recv [[*%d*]] bytes pop3 data  from IP:[[*%x*]]<-->Port:[[*%d*]]", cbSize, iph->ipSource, port);
pBuffer = (PCHAR)ExAllocatePool( NonPagedPool, cbSize + 1 );
RtlCopyMemory( pBuffer, Packet + sizeof(TCPHeader), cbSize);

pBuffer[ cbSize ] = '\0';
dprintf( "%s", pBuffer );
ExFreePool( pBuffer );

}
}
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拦截时的情景：
我在cmd下的操作如下：

+OK POP3 ready
+OK
+OK authorization succeeded (eyou mta)
+OK
1 500
2 500
.
-ERR unimplemented (eyou mta)
+OK
Received: (eyou send program); Wed, 03 Mar 2004 21:37:09 +0800
Message-ID: <278321029.56488@mail.sdu.edu.cn>
Received: from 211.87.213.78 by mail.sdu.edu.cn with HTTP; Wed, 03 Mar 2004 21:3
7:09 +0800
X-WebMAIL-MUA: [211.87.213.78]
From: "相建亭" <x_j_ting@mail.sdu.edu.cn>
To: x_j_ting@mail.sdu.edu.cn
Date: Wed, 03 Mar 2004 21:37:09 +0800
Return-Path: "相建亭" <x_j_ting@mail.sdu.edu.cn>
Reply-To: "相建亭" <x_j_ting@mail.sdu.edu.cn>
Subject: AAAAAAAAAAAA
Content-Type: text/plain

BBBBBBBBBBBBBB


.

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在dbgview下的输出如下：

00000000 0.00000000 recv [[*4*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000001 0.00001620 ]
00000002 0.00174994 recv [[*16*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000003 0.00176950 +OK POP3 ready
00000004 10.12698709 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000005 10.31700118 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000006 10.42714395 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000007 10.52707593 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000008 10.71719227 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000009 11.07712656 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000010 11.29699305 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000011 11.47729502 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000012 11.58708383 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000013 11.86754406 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000014 11.96717264 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000015 12.06726833 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000016 12.19428615 recv [[*6*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000017 12.19430263 +OK  
00000018 13.45732852 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000019 13.58725676 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000020 13.80725288 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000021 13.94760926 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000022 14.12736842 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000023 14.44750073 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000024 14.54718575 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000025 14.64715767 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000026 14.74747712 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000027 14.84726299 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000028 14.85236504 recv [[*40*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000029 14.85237565 +OK authorization succeeded (eyou mta)
00000030 16.15737643 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000031 16.36716398 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000032 16.46742030 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000033 16.57728426 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000034 16.63061814 recv [[*6*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000035 16.63063546 +OK  
00000036 16.82950012 recv [[*17*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000037 16.82951716 1 500
00000038 16.82952275 2 500
00000039 16.82952833 .
00000040 18.31722328 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000041 18.47759226 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000042 18.58724335 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000043 18.93734623 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000044 19.53748060 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000045 20.53744373 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000046 20.88742200 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000047 21.04736803 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000048 21.18696706 recv [[*18*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000049 21.18698494 -ERR unimplemented
00000050 21.34351042 recv [[*13*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000051 21.34352690 (eyou mta)
00000052 22.60859523 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000053 22.75765216 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000054 22.89756463 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000055 23.70776705 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000056 24.01739914 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000057 24.28756392 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000058 24.56396888 recv [[*6*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000059 24.56398593 +OK  
00000060 24.75474760 recv [[*88*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000061 24.75476604 Received: (eyou send program); Wed, 03 Mar 2004 21:37:09 +0800
00000062 24.75477191 Message-ID: <278321029.5
00000063 144.57162544 recv [[*25*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000064 144.57164332 -ERR timeout (eyou mta)
00000065 144.57170478 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
00000066 144.57307060 recv [[*0*]] bytes pop3 data  from IP:[[*80fc2ca*]]<-->Port:[[*110*]]
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请大家为我分析一下怎么回事啊？谢谢了。