Re: How to extract a string

[Guy Harris <guy () alum mit edu>]

On Dec 3, 2009, at 7:57 PM, Rach, Darshan wrote:

> I tried doing the following. But I am still not able to find it.
>
> guint16 loc_name_length =0;
>
> /*Location Name Length*/
> proto_tree_add_item(oqtp_tree, hf_loc_name_length, tvb,  
> packet_field_offset, 1, FALSE);
> loc_name_length = tvb_get_ntohs(tvb, packet_field_offset);

As noted, that's not the length - the two octets before the string are  
0x06 and 0x05, neither of which are the length of an 8-ASCII-character/ 
9-octet (including the terminating '\0') string.

Also, if the name length is 1 octet, you don't fetch it with  
tvb_get_ntohs(), as that fetches *two* octets; you fetch it with  
tvb_get_guint8().  If it's 2 octets, the length in the  
proto_tree_add_item) call should be 2, and you should do

        packet_field_offset += 2;

after fetching the name length.  And the two octets before the string  
aren't the length, in any case - 0x0605 is a lot more than 8 or 9.

Do you have a spec for this protocol?  If so, check it to see what it  
says about the location name.
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