Hi, Klement.
Thank you for your response. We will check the patch carefully. But I
still have question about why IP reassemble is not there or be treated with
lower priority. I think IP reassemble is mandatory feature as tunnel
endpoint.... Please share with me about your thought. Thank you.
BR/Lollita Liu
-----Original Message-----
From: Klement Sekera -X (ksekera - PANTHEON TECHNOLOGIES at Cisco)
[mailto:[email protected]]
Sent: Friday, January 19, 2018 8:26 PM
To: Lollita Liu <[email protected]>; [email protected]
Cc: Kingwel Xie <[email protected]>; Terry Zhang Z
<[email protected]>; Jordy You <[email protected]>
Subject: RE: Why is IP reassemble not supported in VPP?
Hi Lollita Liu,
There is a pending patch in gerrit, which adds the support. So far, it wasn't
reviewed nor merged. I don't have an ETA on that...
https://gerrit.fd.io/r/#/c/9532/
Thanks,
Klement
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> On Behalf Of Lollita Liu
> Sent: Friday, January 19, 2018 5:07 AM
> To: [email protected]
> Cc: Kingwel Xie <[email protected]>; Terry Zhang Z
> <[email protected]>; Jordy You <[email protected]>
> Subject: [vpp-dev] Why is IP reassemble not supported in VPP?
>
> Hi,
>
> We are do investigation in the VPP source code now.
> After checking the source code and doing testing, looks VPP is not able
> handle IP fragment.
>
>
>
> In source code, in function ip4_local_inline, looks
> fragment will be treat as error packet finally because of
> IP4_ERROR_UNKNOWN_PROTOCOL.
>
> /* Treat IP frag packets as "experimental" protocol
> for now
>
> until support of IP frag reassembly is
> implemented */
>
> proto0 = ip4_is_fragment (ip0) ? 0xfe :
> ip0->protocol;
>
> proto1 = ip4_is_fragment (ip1) ? 0xfe :
> ip1->protocol;
>
> ...
>
> next0 = lm->local_next_by_ip_protocol[proto0];
>
> next1 = lm->local_next_by_ip_protocol[proto1];
>
> ...
>
> next0 =
>
> error0 != IP4_ERROR_UNKNOWN_PROTOCOL ?
> IP_LOCAL_NEXT_DROP : next0;
>
> next1 =
>
> error1 != IP4_ERROR_UNKNOWN_PROTOCOL ?
> IP_LOCAL_NEXT_DROP : next1;
>
>
>
> The version is:
>
> DBGvpp# show version
>
> vpp v18.04-rc0~46-gc5239ad built by root on k8s1-node1 at Mon Jan 15
> 06:05:03 UTC 2018
>
>
>
> My question is why IP reassemble is not supported in VPP? It is
> understandable that IP reassemble is not required for pure packet forwarding.
> But as a router platform, there are also plenty of control plane
> packets should be handled, for example BGP packet, IKE packet, that's
> the reason why there is local IP stack on VPP, and IP reassemble is a
> basic requirement of local IP stack. How to handle the case if the BGP
> peer send BGP message in several IP fragment to VPP? One BGP message
> could be quite large depending on route number, and even BGP message
> fragment can be avoid by MSS since it is based on TCP. How about the
> case of IKE peer sending IKE message as IP fragments? The IKE message also
> could be quite large with certificate.......
>
>
>
> BR/Lollita Liu
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