[ieee80211_hwmp][panic] hwmp_recv_prep(...)

[Monthadar Al Jaberi]

I think anytime the destination node sends a PREP to the originator
node that is not a peering node (not in direct contact with) we would
get this panic.

On Wed, Feb 16, 2011 at 8:52 PM, Adrian Chadd <adrian at freebsd.org> wrote:
> Besides being a potential DoS vector (and thus panicing on anything
> like that == bad idea), what legitimate-but-broken circumstances could
> cause a node to hear its own announcement?
>
>
>
> Adrian
>
>
> On 15 February 2011 07:00, Monthadar Al Jaberi <monthadar at gmail.com> wrote:
>> Hej,
>>
>> I found that a panic can be generated when having a couple of
>> ieee80211s nodes in a line topology with one of them being a ROOT
>> node. A ping from ROOT in a newly started nodes causes a panic:
>> panic: ieee80211_mesh_rt_add: adding self to the routing table
>> KDB: enter: panic
>> [ thread pid 0 tid 100030 ]
>> Stopped at      kdb_enter+0x50: lui     at,0x804e
>> db>
>>
>> This is because we receive a copy of our own generated
>> IEEE80211_ELEMID_MESHPREP packet from our neighbor node.
>> I added check code in the begining of hwmp_recv_prep(...) similar to
>> the check code found in hwmp_recv_preq(...). Here is a diff output:
>>
>> --- freebsd/head/sys/net80211/ieee80211_hwmp.c  2010-11-03
>> 09:29:25.023610380 +0000
>> +++ src/head-current/sys/net80211/ieee80211_hwmp.c      2011-02-15
>> 10:06:02.526163874 +0000
>> @@ -28,7 +28,7 @@
>>  */
>>  #include <sys/cdefs.h>
>>  #ifdef __FreeBSD__
>> -__FBSDID("$FreeBSD$");
>> +__FBSDID("$FreeBSD: src/sys/net80211/ieee80211_hwmp.c,v 1.4.2.7.2.1
>> 2010/12/21 17:09:25 kensmith Exp $");
>>  #endif
>>
>>  /*
>> @@ -951,6 +951,12 @@
>>        if (ni == vap->iv_bss ||
>>            ni->ni_mlstate != IEEE80211_NODE_MESH_ESTABLISHED)
>>                return;
>> +       /*
>> +        * Ignore PREPs from us. Could happen because someone forward it
>> +        * back to us.
>> +        */
>> +       if (IEEE80211_ADDR_EQ(vap->iv_myaddr, prep->prep_targetaddr))
>> +               return;
>>        if (!IEEE80211_ADDR_EQ(vap->iv_myaddr, prep->prep_origaddr) &&
>>            !(ms->ms_flags & IEEE80211_MESHFLAGS_FWD))
>>                return;
>>
>> --
>> //Monthadar Al Jaberi
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>



-- 
//Monthadar Al Jaberi