From: roopa <roopa@cumulusnetworks•com>
To: "Eric W. Biederman" <ebiederm@xmission•com>
Cc: David Miller <davem@davemloft•net>,
netdev@vger•kernel.org,
Stephen Hemminger <stephen@networkplumber•org>,
santiago@crfreenet•org,
Vivek Venkatraman <vivek@cumulusnetworks•com>
Subject: Re: [PATCH net-next 7/8] mpls: Multicast route table change notifications
Date: Thu, 26 Feb 2015 07:12:34 -0800 [thread overview]
Message-ID: <54EF37E2.1040506@cumulusnetworks.com> (raw)
In-Reply-To: <87oaogn51k.fsf@x220.int.ebiederm.org>
On 2/26/15, 6:03 AM, Eric W. Biederman wrote:
> roopa <roopa@cumulusnetworks•com> writes:
>
>> On 2/25/15, 9:19 AM, Eric W. Biederman wrote:
>>> Unlike IPv4 this code notifies on all cases where mpls routes
>>> are added or removed as that was the simplest to implement.
>>>
>>> In particular routes being removed because a network interface
>>> goes down or is removed are notified about. Are there technical
>>> arguments for handling this differently ? Userspace developers
>>> don't particularly like the way IPv4 handles route removal
>>> on ifdown.
>> that is true. However, from previous emails on this topic on netdev,
>> there is no reason to notify these deletes to userspace thereby creating a
>> notification storm
>> when userspace can figure this out. Which seems like a valid reason.
>> (Your approach resembles IPv6 which does generate these notifications and
>> userspace is usually happy with this).
> Grr. There is an even better way to do this.
>
> The semantically best way to handle this is to simply not use routes for
> forwarding where the network inteface is down, the carrier is down, or
> the network device has gone away for forwarding.
agreed, And we have an internal patch that does this for regular routing
on carrier down (which we will upstream soon).
>
> Apparently there are some multi-path scenearios that already do this
> legitimately, and routes going away auto-matically can cause userspace
> other kinds of problems.
>
> In MPLS I especially don't want to free the routing table slot until I
> know that the change has propagated in the network and I can be
> reasonably confident that no-one will send me traffic on that label.
> Otherwise there is a chance the label will be reused too soon.
ack
>
> Grumble. That is a code change I need to make. Grumble.
>
> I also need to look and see if those multi-path scenarios report a next
> hop as dead or just rely on the network interface state (which I think
> it is) to be sufficient information relayed to userspace
>
they are marked DEAD on ifdown today (AFAIR they dont generate a
notification in IPv4) and are skipped during route lookup.
Only when all the nexthops in a multi-path route are dead, is the route
multipath route declared dead
and is deleted today (with no notification to userspace in the IPv4 case).
Thanks,
Roopa
next prev parent reply other threads:[~2015-02-26 15:12 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-25 17:09 [PATCH net-next 0/8] Basic MPLS support Eric W. Biederman
2015-02-25 17:13 ` [PATCH net-next 1/8] mpls: Refactor how the mpls module is built Eric W. Biederman
2015-02-26 2:05 ` Simon Horman
2015-02-26 2:15 ` Eric W. Biederman
2015-02-26 2:28 ` Simon Horman
2015-02-25 17:14 ` [PATCH net-next 2/8] mpls: Basic routing support Eric W. Biederman
2015-02-25 17:15 ` [PATCH net-next 3/8] mpls: Add a sysctl to control the size of the mpls label table Eric W. Biederman
2015-02-25 17:16 ` [PATCH net-next 4/8] mpls: Basic support for adding and removing routes Eric W. Biederman
2015-02-25 17:16 ` [PATCH net-next 5/8] mpls: Functions for reading and wrinting mpls labels over netlink Eric W. Biederman
2015-02-25 17:17 ` [PATCH net-next 6/8] mpls: Netlink commands to add, remove, and dump routes Eric W. Biederman
2015-02-25 17:18 ` [PATCH net-next 8/8] ipmpls: Basic device for injecting packets into an mpls tunnel Eric W. Biederman
2015-03-05 9:17 ` Vivek Venkatraman
2015-03-05 14:00 ` Eric W. Biederman
2015-03-05 16:25 ` Vivek Venkatraman
2015-03-05 19:52 ` Eric W. Biederman
2015-03-06 6:05 ` Vivek Venkatraman
2015-03-07 10:36 ` Robert Shearman
2015-03-07 21:12 ` Eric W. Biederman
2015-02-25 17:19 ` [PATCH net-next 7/8] mpls: Multicast route table change notifications Eric W. Biederman
2015-02-26 7:21 ` roopa
2015-02-26 14:03 ` Eric W. Biederman
2015-02-26 15:12 ` roopa [this message]
2015-03-05 1:56 ` Andy Gospodarek
2015-02-25 17:37 ` [PATCH iproute2] mpls: Add basic mpls support to iproute Eric W. Biederman
2015-02-26 6:58 ` [PATCH net-next 0/8] Basic MPLS support roopa
2015-02-27 21:21 ` David Miller
2015-02-28 0:58 ` Eric W. Biederman
2015-03-02 0:05 ` Shrijeet Mukherjee
2015-03-02 4:03 ` David Miller
2015-03-02 5:10 ` Eric W. Biederman
2015-03-02 5:53 ` David Miller
2015-03-02 5:59 ` [PATCH net-next 0/15] Neighbour table and ax25 cleanups Eric W. Biederman
2015-03-02 5:59 ` [PATCH net-next 01/15] ax25: In ax25_rebuild_header add missing kfree_skb Eric W. Biederman
2015-03-02 6:01 ` [PATCH net-next 02/15] rose: Set the destination address in rose_header Eric W. Biederman
2015-03-02 6:02 ` [PATCH net-next 03/15] rose: Transmit packets in rose_xmit not rose_rebuild_header Eric W. Biederman
2015-03-02 6:03 ` [PATCH net-next 04/15] ax25/kiss: Replace ax_header_ops with ax25_header_ops Eric W. Biederman
2015-03-02 6:03 ` [PATCH net-next 05/15] ax25/6pack: Replace sp_header_ops " Eric W. Biederman
2015-03-02 6:04 ` [PATCH net-next 06/15] ax25: Make ax25_header and ax25_rebuild_header static Eric W. Biederman
2015-03-02 6:05 ` [PATCH net-next 07/15] ax25: Refactor to use private neighbour operations Eric W. Biederman
2015-03-02 6:06 ` [PATCH net-next 08/15] arp: Remove special case to give AX25 it's open arp operations Eric W. Biederman
2015-03-02 6:07 ` [PATCH net-next 09/15] neigh: Move neigh_compat_output into ax25_ip.c Eric W. Biederman
2015-03-02 6:08 ` [PATCH net-next 10/15] ax25: Stop calling/abusing dev_rebuild_header Eric W. Biederman
2015-03-02 6:09 ` [PATCH net-next 11/15] ax25: Stop depending on arp_find Eric W. Biederman
2015-03-02 6:11 ` [PATCH net-next 12/15] net: Kill dev_rebuild_header Eric W. Biederman
2015-03-02 6:12 ` [PATCH net-next 13/15] arp: Kill arp_find Eric W. Biederman
2015-03-02 6:13 ` [PATCH net-next 14/15] neigh: Don't require dst in neigh_hh_init Eric W. Biederman
2015-03-02 6:14 ` [PATCH net-next 15/15] neigh: Don't require a dst in neigh_resolve_output Eric W. Biederman
2015-03-02 21:44 ` [PATCH net-next 0/15] Neighbour table and ax25 cleanups David Miller
2015-03-03 15:41 ` [PATCH net-next] ax25: Stop using magic neighbour cache operations Eric W. Biederman
2015-03-03 19:45 ` David Miller
2015-03-03 20:22 ` Eric W. Biederman
2015-03-03 20:33 ` David Miller
2015-03-03 23:09 ` [PATCH net-next 0/2] Neighbour table prep for MPLS Eric W. Biederman
2015-03-03 23:10 ` [PATCH net-next 1/2] neigh: Factor out ___neigh_lookup_noref Eric W. Biederman
2015-03-04 14:53 ` Andy Gospodarek
2015-03-04 15:58 ` Eric W. Biederman
2015-03-04 16:30 ` Andy Gospodarek
2015-03-03 23:11 ` [PATCH net-next 2/2] neigh: Add helper function neigh_xmit Eric W. Biederman
2015-03-04 1:06 ` [PATCH net-next 0/7] Basic MPLS support take 2 Eric W. Biederman
2015-03-04 1:10 ` [PATCH net-next 1/7] mpls: Refactor how the mpls module is built Eric W. Biederman
2015-03-04 1:10 ` [PATCH net-next 2/7] mpls: Basic routing support Eric W. Biederman
2015-03-05 16:36 ` Vivek Venkatraman
2015-03-05 18:42 ` Eric W. Biederman
2015-03-04 1:11 ` [PATCH net-next 3/7] mpls: Add a sysctl to control the size of the mpls label table Eric W. Biederman
2015-03-05 9:45 ` Vivek Venkatraman
2015-03-05 13:22 ` Eric W. Biederman
2015-03-05 14:38 ` Eric W. Biederman
2015-03-05 16:49 ` Vivek Venkatraman
2015-03-04 1:12 ` [PATCH net-next 4/7] mpls: Basic support for adding and removing routes Eric W. Biederman
2015-03-04 8:13 ` roopa
2015-03-04 20:36 ` Eric W. Biederman
2015-03-05 0:30 ` roopa
2015-03-05 2:50 ` Bill Fink
2015-03-05 11:54 ` Eric W. Biederman
2015-03-05 19:10 ` Bill Fink
2015-03-04 1:13 ` [PATCH net-next 5/7] mpls: Functions for reading and wrinting mpls labels over netlink Eric W. Biederman
2015-03-04 1:13 ` [PATCH net-next 6/7] mpls: Netlink commands to add, remove, and dump routes Eric W. Biederman
2015-03-04 1:14 ` [PATCH net-next 7/7] mpls: Multicast route table change notifications Eric W. Biederman
2015-03-04 5:27 ` [PATCH net-next 0/7] Basic MPLS support take 2 David Miller
2015-03-04 6:13 ` Eric W. Biederman
2015-03-04 5:25 ` [PATCH net-next 0/2] Neighbour table prep for MPLS David Miller
2015-03-04 5:53 ` Eric W. Biederman
2015-03-04 14:56 ` Andy Gospodarek
2015-03-04 21:04 ` David Miller
2015-03-05 12:35 ` Eric W. Biederman
2015-03-05 10:14 ` [PATCH net-next] ax25: Stop using magic neighbour cache operations Steven Whitehouse
2015-03-06 20:44 ` Eric W. Biederman
2015-03-14 0:33 ` Steven Whitehouse
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