buglwIP - A Lightweight TCP/IP stack - Bugs: bug #49307, IPv6: improper neighbor cache...


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bug #49307: IPv6: improper neighbor cache cleanup

Submitted by:  Dirk Ziegelmeier <dziegel>
Submitted on:  Tue 11 Oct 2016 10:23:44 AM UTC  
Category: IPv6Severity: 3 - Normal
Item Group: NoneStatus: In Progress
Privacy: PublicAssigned to: Simon Goldschmidt <goldsimon>
Open/Closed: OpenPlanned Release: None
lwIP version: git head

Wed 14 Dec 2016 12:18:50 PM UTC, comment #1:

Fixed using NA without lladdr_opt for DAD.

The rest requires more attention as I think there might be some more state changes missing.

Simon Goldschmidt <goldsimon>
Project AdministratorIn charge of this item.
Tue 11 Oct 2016 10:23:44 AM UTC, original submission:

From lwIP mailing list, Arpit Agarwal

Hi Ivan,

I am testing Core Protocols Only.

For e.g. Core Protocols Section 1: (spec.p2) : In my test many of the test cases are failing due to improper neighbor cache cleanup. If I am not wrong, the reason might be non-handling of one of the transition of nd6 state machine (refer link: https://njetwork.files.wordpress.com/2014/01/msi_ipv6-nd-state-machine1.png). I am unable to find the State change from Reachable to Stale on receiving NA with LLADDR change anywhere in the nd6 code.

Similary as per RFC 4861 , DAD-NA might not contain lladdr_opt, but the stack in lwip seems to drop NA if there is not lladdr_opt.

Refer Below code from nd6.c:

/* Unsolicited NA?*/
if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
/* This is an unsolicited NA.
* link-layer changed?
* part of DAD mechanism? */

/* Check that link-layer address option also fits in packet. */
if (p->len < (sizeof(struct na_header) + 2)) {
/* @todo debug message */

lladdr_opt = (struct lladdr_option )((u8_t)p->payload + sizeof(struct na_header));

if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) {
/* @todo debug message */

Dirk Ziegelmeier <dziegel>
Project Administrator


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  • -unavailable- added by goldsimon (Posted a comment)
  • -unavailable- added by dziegel (Submitted the item)

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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Wed 14 Dec 2016 12:18:50 PM UTCgoldsimonStatusNone=>In Progress
      Assigned toNone=>goldsimon

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