Hello list,
Working with the reassembly functionality Ethereal provides I've found
some additional changes had to be made to the EDG 8.4.1:
- a typo (made by myself)
- fragment_add_seq_check() doesn't take -1 as length remaining
- process_reassembled_data() can be called with or without tree, and
is required in both dissection runs
- some whitespace stuff
That's it.
Jaap
Index: EDG_chapter_dissection.xml
===================================================================
--- EDG_chapter_dissection.xml (revision 16218)
+++ EDG_chapter_dissection.xml (working copy)
@@ -763,7 +763,7 @@
.....
}
msg_id INTEGER(0..65535),
- frag_id INTEGER(0..65565),
+ frag_id INTEGER(0..65535),
.....
}
]]>
@@ -782,12 +782,12 @@
guint16 msg_num = tvb_get_ntohs(tvb, offset); offset += 2;
pinfo->fragmented = TRUE;
- frag_msg = fragment_add_seq_check (tvb, offset, pinfo,
+ frag_msg = fragment_add_seq_check(tvb, offset, pinfo,
msg_seqid, /* ID for fragments belonging together */
msg_fragment_table, /* list of message fragments */
msg_reassembled_table, /* list of reassembled messages */
msg_num, /* fragment sequence number */
- -1, /* fragment length - to the end */
+ tvb_length_remaining(tvb, offset), /* fragment length - to the end */
flags & FL_FRAG_LAST); /* More fragments? */
]]>
</programlisting></example>
@@ -821,7 +821,7 @@
msg_num is the packet number within the sequence.
</para></listitem>
<listitem><para>
- The length here is specified as -1, as we want the rest of the packet data.
+ The length here is specified as the rest of the tvb as we want the rest of the packet data.
</para></listitem>
<listitem><para>
Finally a parameter that signals if this is the last fragment or not.
@@ -832,19 +832,17 @@
<example><title>Reassembling fragments part 2</title>
<programlisting>
<![CDATA[
- if (msg_tree)
- new_tvb = process_reassembled_data(tvb, offset, pinfo,
+ new_tvb = process_reassembled_data(tvb, offset, pinfo,
"Reassembled Message", frag_msg, &msg_frag_items,
NULL, msg_tree);
if (frag_msg) { /* Reassembled */
- if (check_col (pinfo->cinfo, COL_INFO))
- col_append_str (pinfo->cinfo, COL_INFO,
+ if (check_col(pinfo->cinfo, COL_INFO))
+ col_append_str(pinfo->cinfo, COL_INFO,
" (Message Reassembled)");
- } else {
- /* Not last packet of reassembled Short Message */
- if (check_col (pinfo->cinfo, COL_INFO))
- col_append_fstr (pinfo->cinfo, COL_INFO,
+ } else { /* Not last packet of reassembled Short Message */
+ if (check_col(pinfo->cinfo, COL_INFO))
+ col_append_fstr(pinfo->cinfo, COL_INFO,
" (Message fragment %u)", msg_num);
}
@@ -858,16 +856,14 @@
next_tvb = tvb_new_subset(tvb, offset, -1, -1);
}
-offset = 0;
+.....
pinfo->fragmented = save_fragmented;
]]>
</programlisting></example>
<para>
Having passed the fragment data to the reassembly handler, we can
- now check if we have the whole message. We can only do this if were
- in the display mode, as we need to pass the display tree parameter into this
- routine. If there is enough information, this routine will return the
- newly reassembled data buffer.
+ now check if we have the whole message. If there is enough information,
+ this routine will return the newly reassembled data buffer.
</para>
<para>
After that, we add a couple of informative messages to the display
