Wireshark · Ethereal-dev: Re: [Ethereal-dev] FT_IPv4 and little_endian = 1 (Bug report for proto_tree_add_item)

[Peter Johansson <Peter.xc.Johansson@xxxxxxxxxxxx>]

How about this one (FT_IPv4 ignoring little_endian = 1)?
Does anyone want to take a stand?
If no arguments shoots a hole in this, how do I add the suggested change 
in proto.c to CVS (who approves that)?

/ Peter

Peter Johansson wrote:

> The protocol I am writing a dissector for sends (among other things) 
> the IP address that the data connection should be made on (similar to 
> FTP).
> The problem I have is that the IP v4 address is in little endian 
> format in the protocol data. Hence I tried:
>
> proto_tree_add_item(dsd_tree,
>                    hf_dsd_ip_address_1,
>                    tvb,
>                    OCP_HEADER_SIZE + DSD_HEADER_SIZE + 6,
>                    4,
>                    TRUE); /* DATA IS LITTLE ENDIAN */
>
>
> hf_dsd_ip_address_1 is defined as:
> &hf_dsd_ip_address_1,
> {
>   "IP address 1", "ocp.dsd.addr_1",
>   FT_IPv4, BASE_NONE, NULL, 0x0,
>   ""
> }
>
> The problem is that the address that should be shown as i.e. 
> 192.168.1.2 is shown as 2.1.168.192 since proto_tree_add_item in 
> proto.c ignores the little_endian flag  for the type FT_IPv4.
> Is this by design or is it a misfeature (bug)?
>
> I suggest a change in proto.c from:
> proto_tree_set_ipv4(new_fi, value);
>
> to:
> proto_tree_set_ipv4(new_fi, little_endian ? GUINT32_TO_BE(value) : 
> value);
> Since proto_tree_set_ipv4 expects big endian data, the value must be 
> converted to BE if LE.
>
> diff -u information follows:
>
> --- proto.c     Fri Aug 13 00:41:54 2004
> +++ modified_proto.c    Thu Sep 02 12:06:25 2004
> @@ -722,7 +722,7 @@
>                case FT_IPv4:
>                        g_assert(length == 4);
>                        tvb_memcpy(tvb, (guint8 *)&value, start, 4);
> -                       proto_tree_set_ipv4(new_fi, value);
> +                       proto_tree_set_ipv4(new_fi, little_endian ? 
> GUINT32_TO_BE(value) : value);
>                        break;
>
>                case FT_IPXNET:
>
> / Regards, Peter
>
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