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Handle NBSS messages where the NBSS *header* is split across TCP segment 

boundaries.

svn path=/trunk/; revision=4831
This commit is contained in:
Guy Harris 2002-02-28 23:09:03 +00:00
parent d96747f550
commit 02a0666ce9
1 changed files with 50 additions and 16 deletions
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66
packet-nbns.c
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@ -3,7 +3,7 @@
* to when it had only NBNS)
* Guy Harris <guy@alum.mit.edu>
*
* $Id: packet-nbns.c,v 1.73 2002/02/18 23:51:55 guy Exp $
* $Id: packet-nbns.c,v 1.74 2002/02/28 23:09:03 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -1359,6 +1359,7 @@ dissect_nbss_packet(tvbuff_t *tvb, int offset, packet_info *pinfo,
guint8 msg_type;
guint8 flags;
volatile int length;
int length_remaining;
int len;
char name[(NETBIOS_NAME_LEN - 1)*4 + MAXDNAME];
int name_type;
@ -1366,8 +1367,28 @@ dissect_nbss_packet(tvbuff_t *tvb, int offset, packet_info *pinfo,
tvbuff_t *next_tvb;
const char *saved_proto;
msg_type = tvb_get_guint8(tvb, offset);
/* Desegmentation */
length_remaining = tvb_length_remaining(tvb, offset);
/*
* Can we do reassembly?
*/
if (nbss_desegment && pinfo->can_desegment) {
/*
* Yes - is the NBSS header split across segment boundaries?
*/
if (length_remaining < 4) {
/*
* Yes. Tell our caller how many more bytes
* we need.
*/
return -(4 - length_remaining);
}
}
/*
* Get the length of the NBSS message.
*/
if (is_cifs) {
flags = 0;
length = tvb_get_ntoh24(tvb, offset + 1);
@ -1378,25 +1399,24 @@ dissect_nbss_packet(tvbuff_t *tvb, int offset, packet_info *pinfo,
length += 65536;
}
/*Desegmentation */
if (nbss_desegment) {
if (pinfo->can_desegment
&& length > tvb_length_remaining(tvb, offset+4)) {
/*
* Can we do reassembly?
*/
if (nbss_desegment && pinfo->can_desegment) {
/*
* Yes - is the NBSS message split across segment boundaries?
*/
if (length_remaining < length + 4) {
/*
* This frame doesn't have all of the data for
* this message, but we can do reassembly on it.
*
* Tell the TCP dissector where the data for this
* message starts in the data it handed us, and
* how many more bytes we need, and return.
* Yes. Tell our caller how many more bytes
* we need.
*/
pinfo->desegment_offset = offset;
pinfo->desegment_len =
length - tvb_length_remaining(tvb, offset+4);
return max_data;
return -((length + 4) - length_remaining);
}
}
msg_type = tvb_get_guint8(tvb, offset);
if (tree) {
ti = proto_tree_add_item(tree, proto_nbss, tvb, offset, length + 4, FALSE);
nbss_tree = proto_item_add_subtree(ti, ett_nbss);
@ -1687,6 +1707,20 @@ dissect_nbss(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
while (max_data > 0) {
len = dissect_nbss_packet(tvb, offset, pinfo, tree, max_data,
is_cifs);
if (len < 0) {
/*
* We need more data to dissect this, and
* desegmentation is enabled. "-len" is the
* number of additional bytes of data we need.
*
* Tell the TCP dissector where the data for this
* message starts in the data it handed us, and
* how many more bytes we need, and return.
*/
pinfo->desegment_offset = offset;
pinfo->desegment_len = -len;
return;
}
offset += len;
max_data -= len;
}