在做大学最后的毕业设计了,无线局域网络远程安全监控策略
那么抓包是这个系统设计的基础
以前一直都是知道用winpcap的,现在网上搜了一下,有用C#封装好了的,很好用
下面是其中的几个用法
这个类库作者的主页:http://www.tamirgal.com/home/default.aspx
PcapOpen()有下面几个方法
- PcapOpen()
- PcapOpen(bool promiscuous_mode)
- PcapOpen(bool promiscuous_mode, int read_timeout)
promiscuous_mode:在普通的抓取模式下,我们只抓取那些目的地为目标网络的包,而处于promiscuous_mode时,则抓取所有的包,包括转发的包.通常我们都是开启这种模式的
下面是示例:
//
Extract a device from the list
PcapDevice device
=
devices[i];

//
Register our handler function to the


//
'packet arrival' event
device.PcapOnPacketArrival
+=

new
SharpPcap.PacketArrivalEvent(device_PcapOnPacketArrival);

//
Open the device for capturing
//
true -- means promiscuous mode


//
1000 -- means a read wait of 1000ms
device.PcapOpen(
true
,
1000
);


Console.WriteLine(

"
-- Listenning on {0}, hit 'Enter' to stop...
"
,

device.PcapDescription);


//
Start the capturing process
device.PcapStartCapture();


//
Wait for 'Enter' from the user.

Console.ReadLine();


//
Stop the capturing process

device.PcapStopCapture();

//
Close the pcap device
device.PcapClose();

PcapStartCapture()
对应PcapStopCapture()
使用PcapCapture(
int packetCount)
时我们可以使用
SharpPcap.INFINITE,
来达到持续抓包的功能
Note:通常CRC的数据是不在数据包的中的,因为通常错误的CRC包会被自动丢弃.
上面的需要注册一个event handle,这在很多时候是不可行的,所以我们推荐使用下面这个方法PcapGetNextPacket()
//
Extract a device from the list
PcapDevice device
=
devices[i];

//
Open the device for capturing
//
true -- means promiscuous mode
//
1000 -- means a read wait of 1000ms
device.PcapOpen(
true
,
1000
);
Console.WriteLine();
Console.WriteLine(
"
-- Listenning on {0}...
"
,
device.PcapDescription);
Packet packet
=
null
;

//
Keep capture packets using PcapGetNextPacket()
while
( (packet
=
device.PcapGetNextPacket())
!=
null
)


{

// Prints the time and length of each received packet


DateTime time = packet.PcapHeader.Date;

int len = packet.PcapHeader.PacketLength;

Console.WriteLine("{0}:{1}:{2},{3} Len={4}",

time.Hour, time.Minute, time.Second,

time.Millisecond, len);

}

//
Close the pcap device

device.PcapClose();

Console.WriteLine(
"
-- Capture stopped, device closed.
"
);

PcapSetFilter()
设置过滤条件
string filter = "ip and tcp";
device.PcapSetFilter( filter );
下面这个例子通过抓取TCP包,输出他们的时间,长度,源IP,源端口,目的IP,目的端口
///

/// Prints the time, length, src ip,


/// src port, dst ip and dst port

/// for each TCP/IP packet received on the network


///

private
static
void
device_PcapOnPacketArrival(

object
sender, Packet packet)


{

if(packet is TCPPacket)


{

DateTime time = packet.Timeval.Date;

int len = packet.PcapHeader.len;


TCPPacket tcp = (TCPPacket)packet;

string srcIp = tcp.SourceAddress;

string dstIp = tcp.DestinationAddress;

int srcPort = tcp.SourcePort;

int dstPort = tcp.DestinationPort;


Console.WriteLine("{0}:{1}:{2},


{3} Len={4} {5}:{6} -> {7}:{8}",

time.Hour, time.Minute, time.Second,

time.Millisecond, len, srcIp, srcPort,

dstIp, dstPort);

}

}