netdev - Re: [PATCH v3 0/6] ipv6: Do route updating for redirect in ndisc layer

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Message-ID: <5236F808.9050605@redhat.com>
Date:	Mon, 16 Sep 2013 14:22:32 +0200
From:	Daniel Borkmann <dborkman@...hat.com>
To:	Duan Jiong <duanj.fnst@...fujitsu.com>
CC:	davem@...emloft.net, netdev@...r.kernel.org,
	hannes@...essinduktion.org,
	"linux-sctp@...r.kernel.org" <linux-sctp@...r.kernel.org>
Subject: Re: [PATCH  v3 0/6] ipv6: Do route updating for redirect in ndisc
 layer

On 09/16/2013 01:47 PM, Duan Jiong wrote:
> From: Duan Jiong <duanj.fnst@...fujitsu.com>
> 
> the ip6_redirect() could be replaced with
> ip6_redirect_no_header(), we could always use ip6_redirect()
> for route updating in ndisc layer and use the data of the
> redirected header option just for finding the socket to be
> notified and then notify user in protocols' err_handler.

If I get this right, it seems to me that this patchset actually consists of two
different kind of changes:

1) Not notifying user space on ICMP redirects (net material)
2) Simplify code for updating route in ndisc layer instead of error handlers (net-next)

Also, you do the *actual* change in the very last patch, which means that from
patch 1 to 5 we're in an inconsistent and buggy state unless we also apply patch
number 6. It should actually be the other way around, that you first do the actual
change and then migrate users (also commit messages are quite terse).

Moreover, just looking at the SCTP part (sctp_err_lookup() function) ...

/* RFC 4960, Appendix C. ICMP Handling
 *
 * ICMP6) An implementation MUST validate that the Verification Tag
 * contained in the ICMP message matches the Verification Tag of
 * the peer.  If the Verification Tag is not 0 and does NOT
 * match, discard the ICMP message.  If it is 0 and the ICMP
 * message contains enough bytes to verify that the chunk type is
 * an INIT chunk and that the Initiate Tag matches the tag of the
 * peer, continue with ICMP7.  If the ICMP message is too short
 * or the chunk type or the Initiate Tag does not match, silently
 * discard the packet.
 */

... it seems to me that we would simply ignore such RFC requirements with
your patch for the sctp_v6_err() part.

Care to elaborate? ;-)

> ---
>   Changes for v3:
>   1.del the ICMP6_INC_STATS_BH  error count, these are in fact
>     no errors.
> 
>   Changes for v2:
>   1.handle the update of the NDISC_REDIRECT error code directly in
>     icmpv6_err_convert.
>   2.squash some patchs into one patch.
>   3.modify the subject of those patchs.
> 
> Duan Jiong (6):
>    ipv6: del the statements for updating route in (dccp|tcp|sctp)_v6_err
>    ipv6: just match on ICMPV6_PKT_TOOBIG in those err_handle
>    ipv6: del statements for dealing with NDISC_REDIRECT
>    ip6tnl: move route updating for redirect to ndisc layer
>    ipv6: modify the err to 0 when dealing with NDISC_REDIRECT
>    ipv6: Do route updating for redirect in ndisc layer
> 
>   include/net/ip6_route.h |  3 ---
>   net/dccp/ipv6.c         | 13 +------------
>   net/ipv6/ah6.c          |  9 ++-------
>   net/ipv6/esp6.c         |  9 ++-------
>   net/ipv6/icmp.c         |  5 +++--
>   net/ipv6/ip6_tunnel.c   |  5 -----
>   net/ipv6/ipcomp6.c      |  9 ++-------
>   net/ipv6/ndisc.c        |  6 ++----
>   net/ipv6/raw.c          |  3 +--
>   net/ipv6/route.c        | 29 ++---------------------------
>   net/ipv6/tcp_ipv6.c     | 12 ++++--------
>   net/ipv6/udp.c          |  2 --
>   net/sctp/input.c        | 12 ------------
>   net/sctp/ipv6.c         |  6 +++---
>   14 files changed, 22 insertions(+), 101 deletions(-)
> 
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