[support] Destination unreachable from HA on BU???

[Arnaud Ebalard]

Hi,

Romain KUNTZ <kuntz at lsiit.u-strasbg.fr> writes:

> On 2009/03/25, at 11:34, Mattias Blomqvist wrote:
>> Tcpdump of a received BU:
>> HA:~# tcpdump -vvv -x -i eth0 -s 200 host xxxx:xxxx::1
>> tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture  
>> size 200 bytes
>> 12:16:42.450564 IP6 (hlim 63, next-header IPv6 (41)
>
> Next header should be destination option header (0x3c)

Yep, that's weird. The layout of the packet imported in Scapy is the
following (replaced xxxx xxxx and yyyy yyyy values by 2001:db8:: and
2001:db8::): 

###[ IPv6 ]###
  version= 6L
  tc= 0L
  fl= 0L
  plen= 72
  nh= IPv6
  hlim= 63
  src= 2001:db9::13
  dst= 2001:db8::1
###[ IPv6 ]###
     version= 6L
     tc= 0L
     fl= 0L
     plen= 32
     nh= Mobility Header
     hlim= 64
     src= 2001:db8:0:1300::1
     dst= 2001:db8::1
###[ IPv6 Mobility Header - Binding Update ]###
        nh= No Next Header
        len= 3
        mhtype= BU
        res= 0
        cksum= 0x20a
        seq= 0x48fd
        flags= HA
        reserved= 0x0L
        mhtime= 262140 sec
        autopad= On
        \options\
         |###[ PadN ]###
         |  otype= PadN [00: skip, 0: Don't change en-route]
         |  optlen= 0
         |  optdata= ''
         |###[ MIPv6 Option - Alternate Care-of Address ]###
         |  otype= Alternate Care-of Address
         |  olen= 16
         |  acoa= 2001:db9::13

Having  2001:db9::13 in the altcoa option and in the *external* IPv6
header is just weird. 2001:db8:0:1300::1 is not an autoconfigured
address, so Additional questions about your MN:

- how does it get that 2001:db8:0:1300::1 address?
- you are also running UMIP on the MN? can you send the config?
- On a recent kernel?
- Any exotic network config (i.e. not ethernet or wifi), like some
  tunneling mechanism ?

Cheers,

a+