[LARTC] RTNETLINK answers: File exists

[LARTC] RTNETLINK answers: File exists

[Whit Blauvelt]

Can someone tell me what concept I'm missing here. The setup is simple. I
have two default routes after ifup operations. I use "ip route del" to
remove one, but then decide to add it back. The attempt is refused. Why?

# ip route ls
66.95.83.208/28 dev eth1  proto kernel  scope link  src 66.95.83.210 
65.84.205.96/27 dev eth2  proto kernel  scope link  src 65.84.205.104 
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.245 
66.0.0.0/8 dev eth1  proto kernel  scope link  src 66.95.83.210 
default via 65.84.205.97 dev eth2 
default via 66.95.83.209 dev eth1 

# ip route del default via 65.84.205.97 dev eth2

# ip route ls
66.95.83.208/28 dev eth1  proto kernel  scope link  src 66.95.83.210 
65.84.205.96/27 dev eth2  proto kernel  scope link  src 65.84.205.104 
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.245 
66.0.0.0/8 dev eth1  proto kernel  scope link  src 66.95.83.210 
default via 66.95.83.209 dev eth1 

# ip route add default via 65.84.205.97 dev eth2
RTNETLINK answers: File exists

Thanks,
Whit

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Re: [LARTC] RTNETLINK answers: File exists

[Julian Anastasov]

	Hello,

On Mon, 26 Nov 2001, Whit Blauvelt wrote:

> default via 66.95.83.209 dev eth1
>
> # ip route add default via 65.84.205.97 dev eth2
> RTNETLINK answers: File exists

	It seems you are trying to use alternative routes. Use
"ip route append" instead. You can also look at the following
URL where the alt routes are extended:

http://www.linuxvirtualserver.org/~julian/
look for "Static, Alternative Routes, Dead Gateway Detection, NAT"

and also in dgd-usage.txt

> Thanks,
> Whit

Regards

--
Julian Anastasov <ja@ssi.bg>


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RE: [LARTC] RTNETLINK answers: File exists

[Greg Scott]

Maybe this also applies to the problem I have been fighting for the last
several weeks.  I have a VPN situation that requires a Linux router/firewall
to route packets back out the same interface on which they came in.  

Julian, I saw this quote in the website you mentioned:

By default, the Linux kernels drop packets with local source address from
the forward path as "source martians". This is not controlled from the
rp_filter flags. The following patches try to relax this rule and to allow
the LVS director to be used as (default) gateway from real servers that send
packets with VIP source, i.e. when the same IP is configured on the LVS
director. 


What does this mean?  Is this quote telling me that Linux kernels drop
packets when their routes to the next hop go out the same interface on which
they came in?

thanks

- Greg Scott




-----Original Message-----
From: Julian Anastasov [mailto:ja@ssi.bg]
Sent: Monday, November 26, 2001 12:51 PM
To: Whit Blauvelt
Cc: LARTC@mailman.ds9a.nl
Subject: Re: [LARTC] RTNETLINK answers: File exists



	Hello,

On Mon, 26 Nov 2001, Whit Blauvelt wrote:

> default via 66.95.83.209 dev eth1
>
> # ip route add default via 65.84.205.97 dev eth2
> RTNETLINK answers: File exists

	It seems you are trying to use alternative routes. Use
"ip route append" instead. You can also look at the following
URL where the alt routes are extended:

http://www.linuxvirtualserver.org/~julian/
look for "Static, Alternative Routes, Dead Gateway Detection, NAT"

and also in dgd-usage.txt

> Thanks,
> Whit

Regards

--
Julian Anastasov <ja@ssi.bg>


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RE: [LARTC] RTNETLINK answers: File exists

[Julian Anastasov]

	Hello,

On Mon, 26 Nov 2001, Greg Scott wrote:

> Maybe this also applies to the problem I have been fighting for the last
> several weeks.  I have a VPN situation that requires a Linux router/firewall
> to route packets back out the same interface on which they came in.

	You need symmetric routes and rp_filter is one of the
solutions. If the problem involves tunnels then rp_filter can cause
problems in some situations.

> Julian, I saw this quote in the website you mentioned:
>
> By default, the Linux kernels drop packets with local source address from
> the forward path as "source martians". This is not controlled from the
> rp_filter flags. The following patches try to relax this rule and to allow
> the LVS director to be used as (default) gateway from real servers that send
> packets with VIP source, i.e. when the same IP is configured on the LVS
> director.
>
>
> What does this mean?  Is this quote telling me that Linux kernels drop
> packets when their routes to the next hop go out the same interface on which
> they came in?

	No, this is situation where the clusters have hosts that have
same (shared) IP configured. The internal hosts have IP that is also
configured on their gateway. The patch(es) you mention try to relax the
strict rule in the kernel not to allow packet with saddr=local_ip to be
considered at all (forwarded or delivered locally). We still drop packets
that are locally destined and contain local IP in saddr but we allow
such evil packets to be forwarded (forward_shared flag). In short,
this is a setup where the LVS director is a gateway for Direct-Route
method (you have to read our docs), something similar to NAT topology
but without NAT processing, possible only for specific kind of packets,
i.e. when the port allocation is not a problem (virtual servers).

	But you have to explain your problem with more details or
may be to show me some URLs if it is explained somewhere.

> thanks
>
> - Greg Scott

Regards

--
Julian Anastasov <ja@ssi.bg>


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Re: [LARTC] RTNETLINK answers: File exists

[Whit Blauvelt]

Thanks Julian,

Does anyone know why the heck "ip route" has been programmed so that it
allows something to be deleted that by the same syntax can't be added? This
seems to me to be very, very wrong. Anything that "ip route" shows should be
valid syntax, both for deletion and adding. If the utility is more fussy
about what can be added than what can be deleted, this is very bad
programming. Why has such bad programming been allowed in code that
interacts with the Linux kernel?

Thanks,
Whit

On Mon, Nov 26, 2001 at 08:50:33PM +0200, Julian Anastasov wrote:
> 
> 	Hello,
> 
> On Mon, 26 Nov 2001, Whit Blauvelt wrote:
> 
> > default via 66.95.83.209 dev eth1
> >
> > # ip route add default via 65.84.205.97 dev eth2
> > RTNETLINK answers: File exists
> 
> 	It seems you are trying to use alternative routes. Use
> "ip route append" instead. You can also look at the following
> URL where the alt routes are extended:
> 
> http://www.linuxvirtualserver.org/~julian/
> look for "Static, Alternative Routes, Dead Gateway Detection, NAT"
> 
> and also in dgd-usage.txt
> 
> > Thanks,
> > Whit
> 
> Regards
> 
> --
> Julian Anastasov <ja@ssi.bg>

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Re: [LARTC] RTNETLINK answers: File exists

[Whit Blauvelt]

There is no rule that says there cannot be more than one default - as is
clear because it was possible to set up more than one default route to
begine with! And the error message, "File exists," does not seem to be true
at all, or pertinent. I was not asking to create a file, but a route. 

So I take it that the "ip" utility doesn't follow standard procedures and
practices regarding syntax and error messages? Why has this been allowed in
code that is integrated with the Linux kernel? Was Linus sleeping? 

Whit

On Mon, Nov 26, 2001 at 07:49:50PM +0100, Wojtek Sobola wrote:
> simple... default gateway can be only one :>
> as the name says ;>
> 
> ----- Original Message -----
> From: "Whit Blauvelt" <whit@transpect.com>
> To: <LARTC@mailman.ds9a.nl>
> Sent: Monday, November 26, 2001 7:22 PM
> Subject: [LARTC] RTNETLINK answers: File exists
> 
> 
> > Can someone tell me what concept I'm missing here. The setup is simple. I
> > have two default routes after ifup operations. I use "ip route del" to
> > remove one, but then decide to add it back. The attempt is refused. Why?
> >
> > # ip route ls
> > 66.95.83.208/28 dev eth1  proto kernel  scope link  src 66.95.83.210
> > 65.84.205.96/27 dev eth2  proto kernel  scope link  src 65.84.205.104
> > 192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.245
> > 66.0.0.0/8 dev eth1  proto kernel  scope link  src 66.95.83.210
> > default via 65.84.205.97 dev eth2
> > default via 66.95.83.209 dev eth1
> >
> > # ip route del default via 65.84.205.97 dev eth2
> >
> > # ip route ls
> > 66.95.83.208/28 dev eth1  proto kernel  scope link  src 66.95.83.210
> > 65.84.205.96/27 dev eth2  proto kernel  scope link  src 65.84.205.104
> > 192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.245
> > 66.0.0.0/8 dev eth1  proto kernel  scope link  src 66.95.83.210
> > default via 66.95.83.209 dev eth1
> >
> > # ip route add default via 65.84.205.97 dev eth2
> > RTNETLINK answers: File exists
> >
> > Thanks,
> > Whit
> >
> > _______________________________________________
> > LARTC mailing list / LARTC@mailman.ds9a.nl
> > http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO:
> http://ds9a.nl/2.4Routing/
> >

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Re: [LARTC] RTNETLINK answers: File exists

[Whit Blauvelt]

On Mon, Nov 26, 2001 at 01:22:08PM -0500, Whit Blauvelt wrote:

> # ip route del default via 65.84.205.97 dev eth2

....

> # ip route add default via 65.84.205.97 dev eth2
> RTNETLINK answers: File exists

Let me be clear about this: anything that can be deleted, should be able to
be added. The "File exists" message is quite wrong, since no file creation
has been requested - this is about a route. The error message is worthless,
stupid, and just plain wrong.

Has Linus really allowed such nonsense to be integrated with the kernel?
It's a totally cool idea, being able to do Cisco-type stuff with Linux. But
if the implementation is this lame, it shouldn't have been integrated at
all.

Sorry for being pissed off, but please don't contribute anything to Linux
that isn't done consistently and right!

Whit

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Re: [LARTC] RTNETLINK answers: File exists

[Julian Anastasov]

	Hello,

On Mon, 26 Nov 2001, Whit Blauvelt wrote:

> > # ip route add default via 65.84.205.97 dev eth2
> > RTNETLINK answers: File exists
>
> Let me be clear about this: anything that can be deleted, should be able to
> be added. The "File exists" message is quite wrong, since no file creation
> has been requested - this is about a route. The error message is worthless,
> stupid, and just plain wrong.
>
> Has Linus really allowed such nonsense to be integrated with the kernel?
> It's a totally cool idea, being able to do Cisco-type stuff with Linux. But
> if the implementation is this lame, it shouldn't have been integrated at
> all.

	It seems there are not so much people that use the alternative
routes. You try to use them without understanding them.

> Sorry for being pissed off, but please don't contribute anything to Linux
> that isn't done consistently and right!

	Use the time you spend to write emails to read some docs. You can
read the ip-cref, you can also read my docs. There are many commands:
prepend, append, add. Check where is the difference. "File Exist"
is a result of matching some set of keys. append and add have different
set of keys that are matched. I agree that add and append are similar
but once you understand where is the difference I expect from you to
propose another name for these commands. They work for different
routes. See in my docs what means "alternative routes", how are they
grouped. In short, the alternative routes have equal values for the
keys but differ in other values which are not part from the matching
set and are something as result values, for example, output device,
gateway, etc. As result, the lookup for route is happy when selecting
any of the alternative routes in one group but you agree they should
be different somehow. These additional values don't lead to File Exist
for append and alternative routes because there must be a reason they
to exist at all.

> Whit

Regards

--
Julian Anastasov <ja@ssi.bg>


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[LARTC] RTNETLINK answers: File exists

[Dariusz Dwornikowski]

how can i get rid of that ??
i do del roots before scripting.

-- 
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Re: [LARTC] RTNETLINK answers: File exists

[gypsy]

Dariusz Dwornikowski wrote:
> 
> how can i get rid of that ??
> i do del roots before scripting.

del ingress?
--
gypsy
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Re: [LARTC] RTNETLINK answers: File exists

[Dariusz Dwornikowski]

On Fri, 10 Jun 2005 19:37:55 -0700
gypsy <gypsy@iswest.com> wrote:

> Dariusz Dwornikowski wrote:
> > 
> > how can i get rid of that ??
> > i do del roots before scripting.
> 
> del ingress?
> --
> gypsy
i do nto have ingress, 
but i fixed it : 

my script is generated by python program which creates classes like that :

{
... classid 10%d , i 
i++
}
when classids reach 10100, RTNETLINK occurs. 



-- 
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Re: [LARTC] RTNETLINK answers: File exists

[Thomas Graf]

* Dariusz Dwornikowski <20050611114134.7f453bc6@tdi.pozman.pl> 2005-06-11 11:41
> my script is generated by python program which creates classes like that :
> 
> {
> ... classid 10%d , i 
> i++
> }
> when classids reach 10100, RTNETLINK occurs. 

You're running into the 16bits limit of the major id.
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