Wireshark-dev: [Wireshark-dev] dissecting bits versus bytes

From: Brian Oleksa <oleksab@xxxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 06 May 2011 09:21:50 -0400

I am used to getting a spec sheet of a packet that needs to be dissected and most of the time each part of the packet is in bytes.

For example: The first byte in the packet is the version number. So this is what I would do.

proto_tree_add_item(myproto_sub_tree, hf_myproto_version, tvb, offset, 1, FALSE);
            offset += 1;

    { &hf_myproto_version,
            { "Version", "myproto.version", FT_UINT8, BASE_DEC, NULL, 0x0,
                NULL, HFILL}},

But now I was ordered to dissect a packet that the max size is in bits.

Since a byte is bigger than a bit.....how would you dissect this..??

version   (max field size = 4 bits)..??

Thanks,
Brian