First time here? Check out the FAQ!

Ask Your Question
0

WSGD Bitfields and byte order

asked Mar 22 '19

bilgehan gravatar image

updated Mar 22 '19

grahamb gravatar image

Hi,

I am trying to dissect a protocol with Wireshark Generic dissector. Byte order is big endian for the protocol but bit order is LSB. Relevant fields are below:

enum1 Truth
{
    FALSE 0
    TRUE 1
} 

struct Message
{

   .....

   .....

    Truth[8] fastEth;

    Truth[3] gigaEth;

   .....

   .....
}

When I receive a message in which fastEth[0]=TRUE and rest is FALSE. Dissector shows fastEth[7]=TRUE and rest as FALSE, values are shown as reversed.

  • WSGD has a keyword for byte order (byte_order=big_endian). How can I handle bit order in this situation?

  • Also can I only define bitfieldN when N is multiple of 8?

Thanks

Preview: (hide)

2 Answers

Sort by » oldest newest most voted
0

answered Jan 31 '0

wsgd gravatar image

wsgd does NOT manage bit order


On the displayed example

  • wsgd see 11 data (each of 1 bit)
  • wsgd do not see any group of data

Is the example supposed to show ? :

  • ... no bit order
  • 8 bits where a bit order should be applied
  • 3 bits where a bit order should be applied
  • ... no bit order
Preview: (hide)
link
0

answered Mar 22 '19

grahamb gravatar image

Does this page on bitfields in WSGD help?

Preview: (hide)
link

Comments

bitfieldN : N must be 8 16 24 or 32

wsgd gravatar imagewsgd ( Jan 31 '0 )

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

2 followers

Stats

Asked: Mar 22 '19

Seen: 576 times

Last updated: Jan 31 '20