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[lwip-devel] [bug #37150] snmp_expand_tree mishandles emtpy branches
From: |
Andrew Lynn |
Subject: |
[lwip-devel] [bug #37150] snmp_expand_tree mishandles emtpy branches |
Date: |
Mon, 20 Aug 2012 11:34:26 +0000 |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20100101 Firefox/14.0.1 |
URL:
<http://savannah.nongnu.org/bugs/?37150>
Summary: snmp_expand_tree mishandles emtpy branches
Project: lwIP - A Lightweight TCP/IP stack
Submitted by: alynn
Submitted on: Mon 20 Aug 2012 12:34:25 BST
Category: UDP
Severity: 3 - Normal
Item Group: Faulty Behaviour
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Planned Release:
lwIP version: 1.4.0
_______________________________________________________
Details:
1. Some empty branches can cause the returned object id to lose sync with the
node stack. Descending into a branch after the initial target has been found
does not push onto the stack. If the branch is found to be empty the pop makes
a single decrement of the oidret len rather than adjusting for the number of
levels jumped back up.
2. An empty branch more than a single level deep will cause sibling branches
to its right to be ignored.
1
|
+--+--+
| | |
1 2 3
| | |
0 | 0
|
+-+--+
| |
1 2
| |
+++ +++
Where 1.2.1 and 1.2.2 are both empty.
Searching for the next item from 1.1.0 should return 1.3.0. Unfortunately the
empty_table() function does not detect that 1.2 is empty, since it contains 2
children, even though both children are empty. 1.2 is therefore added to the
stack, being the first 'not empty' node to the right of 1.1, and 1.3 is
ignored.
I have attached a patch to correctly tranverse the tree and fix both of these
issues.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Mon 20 Aug 2012 12:34:25 BST Name: patch_lwip_snmp_tree_walk_fix Size:
19kB By: alynn
<http://savannah.nongnu.org/bugs/download.php?file_id=26401>
_______________________________________________________
Reply to this item at:
<http://savannah.nongnu.org/bugs/?37150>
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- [lwip-devel] [bug #37150] snmp_expand_tree mishandles emtpy branches,
Andrew Lynn <=