netdev - Re: [PATCH net 2/2] sctp: not copying duplicate addrs to the assoc's bind address list

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Date:   Mon, 19 Dec 2016 07:35:02 -0500
From:   Neil Horman <nhorman@...driver.com>
To:     Xin Long <lucien.xin@...il.com>
Cc:     network dev <netdev@...r.kernel.org>, linux-sctp@...r.kernel.org,
        davem <davem@...emloft.net>,
        Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
        Vlad Yasevich <vyasevich@...il.com>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: Re: [PATCH net 2/2] sctp: not copying duplicate addrs to the assoc's
 bind address list

On Sat, Dec 17, 2016 at 05:56:51PM +0800, Xin Long wrote:
> On Wed, Aug 24, 2016 at 6:38 PM, Neil Horman <nhorman@...driver.com> wrote:
> > On Wed, Aug 24, 2016 at 01:14:27PM +0800, Xin Long wrote:
> >> >> > Ah, I see what you're doing.  Ok, this makes some sense, at least on the receive
> >> >> > side, when you get a cookie unpacked and modify the remote peers address list,
> >> >> > it makes sense to check for duplicates.  On the local side however, I would,
> >> >> > instead of checking it when the list gets copied, I'd check it when the master
> >> >> > list gets updated (in the NETDEV_UP event notifier for the local address list,
> >> >>
> >> >> I was thinking about to check it in the NETDEV_UP, yes it can make the
> >> >> master list has no duplicated addresses.  But what if two same addresses
> >> >> events come, and they come from different NICs (though I can't point  out
> >> >> the valid use case), then we filter there.
> >> >>
> >> > That I think would be a bug in the protocol code.  For the ipv4 case, all
> >> > addresses are owned by the system and the same addresses added to multiple
> >> > interfaces should not be allowed.  The same is true of ipv6 case.  The only
> >> > exception there is a link local address and that should still be unique within
> >> > the context of an address/dev tuple.
> >> >
> >> understand, just sounds a little harsh. :-)
> >>
> >> For now, does it make sense to you to just leave as the master list
> >> is, and check
> >> the duplicate address when sctp is really binding them ?
> >>
> > I would think so, yes.
> 
> Hi, Neil,
> 
> About this patch, I think we are on the page, right ?
> 
Yes, I think we are.
Neil

> If yes, I will repost v2, but other than improving some changelog,
> no other change compare to v1. Do you agree ?
>