Wireshark-dev: [Wireshark-dev] Question for how to show the value of Length right in wireshark
From: "li yang" <[email protected]>
Date: Thu, 26 Apr 2007 20:02:13 -0700
Hi,All
   I just start how to write a plugin for own protocal in wireshark
and meet a problem
   Our protocal is based on ethernet and looks like this
   | Length |  Data |  CRC   |

   The length field hold 2 bytes and stands for the length of the data,
   eg, if value is 0x B6 01 , should means the value is 0x 01B6 (438
in decimal)

   I code like followed
	{ &hf_foo_length,
	{ "foo Length",           "foo.length",
	FT_UINT16, BASE_DEC_HEX, NULL, 0x0,
	"", HFILL }
	},

	{ &hf_foo_data,
	{ "foo Data",	"foo.data",	
	FT_UINT16, BASE_HEX,	NULL, 0x0,
	"", HFILL }},

	{ &hf_rdc_crc,
	{ "foo CRC",           "foo.crc",
	FT_UINT32, BASE_DEC, NULL, 0x0,
	"", HFILL }
	}

 I can get the right value in dissect_foo( ) via the followed code.
   data_length = tvb_get_letohs(tvb, offset);

But in the tree view,
1> It always should the Length value is 0xB601 (46593 in decimal)
2> can not show the data field rightly.

So,
1> How could I slove this problem?
2> How could I declare the data in the hf_register_info structure if
the data's length is changeable.

Thanks!!!