Hello,
im just writeing my first dissector and i have some problems with the
reassembling
My prtocoll contain some fields for Snode =ID ,Packetnumber and total
packets
i get them with
snode =tvb_get_guint8(tvb,offset);offset +=1;
pnum =tvb_get_guint8(tvb,offset);offset +=1;
totalp =tvb_get_guint8(tvb,offset);
Example for a packet split into 3 :
Snode=12
pnum=1
total=3
Sonde=12
pnum=2
total=3
Snode=12
pnum=3
total=3
the packet consists of an Trans Header, a App Header and Data.
IF its fragmented only the frist packet consists auf tran,app and
data
the other fragments consists only of trans and data.
For the reassembled tvb only the data are importent. the lengh of the
trans-header r given in a field loh.
I think my fragment_add_seq_check function doesnt work right cause
everytime i get a 0 returned
thx.
Code:
save_fragmented = pinfo->fragmented;
if (totalp > 1 && pnum<=totalp){ //check if it has to be
reassembled
if(pnum==1){
offset2=loh+20; // First packet, Packet
with Tran + App Header ,App Header =20 Byte
}
else{
offset2=loh; // Not First Packet only
trans header
}
if(totalp==pnum){ more_frag=FALSE;} //Total Packet ==
pnum =>Last Packet set more_frags =FALSE
else {more_frag=TRUE;} // Not Last Packet
=>set more_frags=TRUE
msg_seqid =snode;
msg_num = pnum-1;
pinfo->fragmented = TRUE;
frag_msg = fragment_add_seq_check(tvb, offset2, 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
tvb_length_remaining(tvb, offset2), //fragment length
- to the end
more_frag); // More Frag
printf("%d",(int)frag_msg);// PRINTF wieder raus
new_tvb = process_reassembled_data(tvb, offset2, pinfo,
"Reassembled Message", frag_msg, &msg_frag_items,
NULL,nos_tree);
if (frag_msg) { // Reassembled
col_append_str(pinfo->cinfo, COL_INFO,
" (Message Reassembled)");
} else { // Not last packet of reassembled Short Message
col_append_fstr(pinfo->cinfo, COL_INFO,
" (Message fragment %u)", msg_num);
col_append_fstr(pinfo->cinfo, COL_INFO,
" (Frag: %u)", pinfo->fragmented);
col_append_fstr(pinfo->cinfo, COL_INFO,
" (Visit: %u)", pinfo->fd->flags.visited);
col_append_fstr(pinfo->cinfo, COL_INFO,
" (Fragmsg: %d)", (int)frag_msg);
}
if (new_tvb) { // take it all
col_append_str(pinfo->cinfo, COL_INFO,
"(NEW TVB)");
//offset=0;
//proto_tree_add_item(nos_tree, hf_nos_data, new_tvb,
offset, -1, FALSE);
next_tvb = new_tvb;
} else { // make a new subset
next_tvb = tvb_new_subset(tvb, offset2, -1, -1);
}
}
else { // Not fragmented
next_tvb = tvb_new_subset(tvb, offset2, -1, -1);
}
pinfo->fragmented = save_fragmented;
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