c#中socket截取的http包里怎样可以取到url地址呢

socket.BeginReceive(buf, 0, len_receive_buf, SocketFlags.None, new AsyncCallback(CallReceive), this)；

/// <summary>

		/// 根据数据包内容设置各字段

		/// </summary>

		/// <param name="buf"></param>

		public void SetArgs(byte[] buf)

		{

			if( buf == null )

			{

				return;

			}



			string tempReceiveString = BitConverter.ToString( buf );



			m_PackageLength = Convert.ToInt32( tempReceiveString.Substring(6, 2), 16 ) * 16 * 16

				+ Convert.ToInt32( tempReceiveString.Substring(9, 2), 16 );

			string receiveString = tempReceiveString.Substring(0, m_PackageLength * 3 - 1);





			m_IPHeaderLength = Convert.ToInt32( receiveString.Substring(1, 1), 16 ) * 4;

			m_IPHeaderContent = receiveString.Substring( 0, m_IPHeaderLength * 3 - 1 );



			m_IPVersion = m_IPHeaderContent.Substring( 0, 1 );



			

			string protocol = m_IPHeaderContent.Substring(27, 2);

			switch(protocol)

			{

				case "01": 

					m_Protocol = "ICMP"; 

					break;

				case "02": 

					m_Protocol = "IGMP"; 

					break;

				case "06": 

					m_Protocol = "TCP"; 

					break;

				case "11": 

					m_Protocol = "UDP"; 

					break;

				default: 

					m_Protocol = "OTHER"; 

					break;

			}



			string originationIPAddress = m_IPHeaderContent.Substring( 36, 11 );

			m_OriginationIPAddress = getIPAddress( originationIPAddress );



			string destinationIPAddress = m_IPHeaderContent.Substring( 48, 11 );

			m_DestinationIPAddress = getIPAddress( destinationIPAddress );



			m_MessageLength = m_PackageLength - m_IPHeaderLength;

			m_MessageContent = receiveString.Substring( m_IPHeaderLength * 3 );

			

			try		// 这两个字段没用到，但读出来的TCPHeaderLength有可能为空，之后读内容就会因为长度为-1而报错。具体原因待查

			{

				m_TCPHeaderLength = Convert.ToInt32( m_MessageContent.Substring(36, 1), 16 ) * 4;

				m_TCPHeaderContent = m_MessageContent.Substring( 0, m_TCPHeaderLength * 3 - 1 );

			}

			catch

			{

			}



			m_OriginationPort = ( Convert.ToUInt32( m_MessageContent.Substring(0, 2), 16 ) * 16 * 16

				+ Convert.ToUInt32( m_MessageContent.Substring(3, 2), 16 ) ).ToString();

			m_DestinationPort = ( Convert.ToUInt32( m_MessageContent.Substring(6, 2), 16 ) * 16 * 16

				+ Convert.ToUInt32( m_MessageContent.Substring(9, 2), 16 ) ).ToString();

		}