Wireshark-dev: Re: [Wireshark-dev] Byte Ordering in Dissector
From: Guy Harris <[email protected]>
Date: Wed, 30 Apr 2008 10:40:38 -0700
Barry Constantine wrote:

I am running into a problem because the uint32 of my protocol is not in network byte order, but is in reverse byte order.
How can I override the default assumption of network byte order when I 
insert the uint32 into the dissector tree?
You can't...

...because there isn't any default assumption to override!

If you're using proto_tree_add_item(), ptvcursor_add(), or ptvcursor_add_no_advance(), just specify TRUE rather than FALSE as the last argument, to indicate that the value is little-endian rather than big-endian.
If you're using the ptvcursor routines, specify TRUE rather than FALSE 
as the "little_endian" argument.
If you're fetching the value yourself, and the uint32 is *NOT* an IPv4 
addressuse tvb_get_letohl() rather than tvb_get_ntohl() to convert it to 
host byte order.
If you're fetching the value yourself, and the uint32 *IS* an IPv4 
address (i.e., an IPv4 address stored, for some mysterious reason, in 
little-endian byte order rather than big-endian network byte order), use 
tvb_get_ipv4() and then byte-swap the value with GUINT32_SWAP_LE_BE().