Hi all,
Recently I have had a problem with Linux proxy arp feature (using with shaper
interface): when I machine starts up it was receiving a "IP conflits".
The problem is that Linux proxy_arp routine doesn't make difference between
real interface (i.e. eth0) and shaper interface (i.e. shaper0 which has been
attached to eth0).
I attach a first beta solution to the problem, which could be far from
optimal! (I use a "strncmp", cause I didn't found another method to know if
the device is a "shaper" device).
--- arp.c.orig Wed May 16 19:21:45 2001
+++ arp.c Sun Jul 22 19:31:20 2001
@@ -111,7 +111,7 @@
#include <asm/system.h>
#include <asm/uaccess.h>
-
+#include <linux/if_shaper.h>
/*
@@ -767,10 +767,17 @@
}
goto out;
} else if (IN_DEV_FORWARD(in_dev)) {
+ char shflag=0;
+ if ( (rt->u.dst.dev) &&
+ (rt->u.dst.dev->priv) &&
+ (((struct shaper *) rt->u.dst.dev->priv)->dev) &&
+ (strncmp(rt->u.dst.dev->name,"shaper",6)==0) )
+ shflag=1;
if ((rt->rt_flags&RTCF_DNAT) ||
- (addr_type == RTN_UNICAST && rt->u.dst.dev !=
dev &&
+ (addr_type == RTN_UNICAST &&
+ ( ((shflag) && ( ((struct shaper *)
rt->u.dst.dev->priv)->dev != dev)) || ((!shflag) && (rt->u.dst.dev != dev)) )
&&
(IN_DEV_PROXY_ARP(in_dev) ||
pneigh_lookup(&arp_tbl, &tip, dev, 0)))) {
- n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
+ n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
if (n)
The patch declare a variable (flag to know if the interface is shaper-like),
investigate on private data of shaper device (where we can know what is the
attached interface) and set the flag. After we consider the "attached"
interface if flag is set.
I tested it under 2.4.6 on RedHat 7.1 with success (there is no more IP
conflit).
Hope it'll useful.
Best Regards
Roberto Arcomano
Il 22:31, domenica 22 luglio 2001, Roberto Arcomano ha scritto:
> Hi all,
> Recently I have had a problem with Linux proxy arp feature (using with
> shaper interface): when I machine starts up it was receiving a "IP
> conflits". The problem is that Linux proxy_arp routine doesn't make
> difference between real interface (i.e. eth0) and shaper interface (i.e.
> shaper0 which has been attached to eth0).
> I attach a first beta solution to the problem, which could be far from
> optimal! (I use a "strncmp", cause I didn't found another method to know if
> the device is a "shaper" device).
>
>
> --- arp.c.orig Wed May 16 19:21:45 2001
> +++ arp.c Sun Jul 22 19:31:20 2001
> @@ -111,7 +111,7 @@
>
> #include <asm/system.h>
> #include <asm/uaccess.h>
> -
> +#include <linux/if_shaper.h>
>
>
> /*
> @@ -767,10 +767,17 @@
> }
> goto out;
> } else if (IN_DEV_FORWARD(in_dev)) {
> + char shflag=0;
> + if ( (rt->u.dst.dev) &&
> + (rt->u.dst.dev->priv) &&
> + (((struct shaper *) rt->u.dst.dev->priv)->dev)
> && +
> (strncmp(rt->u.dst.dev->name,"shaper",6)==0) ) +
> shflag=1;
> if ((rt->rt_flags&RTCF_DNAT) ||
> - (addr_type == RTN_UNICAST && rt->u.dst.dev !=
> dev &&
> + (addr_type == RTN_UNICAST &&
> + ( ((shflag) && ( ((struct shaper *)
> rt->u.dst.dev->priv)->dev != dev)) || ((!shflag) && (rt->u.dst.dev != dev))
> ) &&
> (IN_DEV_PROXY_ARP(in_dev) ||
> pneigh_lookup(&arp_tbl, &tip, dev, 0)))) {
> - n = neigh_event_ns(&arp_tbl, sha, &sip,
> dev); + n = neigh_event_ns(&arp_tbl, sha,
> &sip, dev); if (n)
>
>
> The patch declare a variable (flag to know if the interface is
> shaper-like), investigate on private data of shaper device (where we can
> know what is the attached interface) and set the flag. After we consider
> the "attached" interface if flag is set.
>
> I tested it under 2.4.6 on RedHat 7.1 with success (there is no more IP
> conflit).
> Hope it'll useful.
>
> Best Regards
> Roberto Arcomano
Please someone takes a look at it! This is a bug of proxy arp feature (when
talking with shaper interface) could be correct (for example using my patch).
Thank you for your help
Best Regards
Roberto Arcomano
Hello!
> Recently I have had a problem with Linux proxy arp feature (using with shaper
You must not enable proxy arp, when routing is asymmetric or configure
it manually. Shaper device is one of cases, when proxy arp cannot work
correctly.
Alexey
Il 00:31, mercoled? 25 luglio 2001, Alexey Kuznetsov ha scritto:
> Hello!
>
> > Recently I have had a problem with Linux proxy arp feature (using with
> > shaper
>
> You must not enable proxy arp, when routing is asymmetric or configure
> it manually. Shaper device is one of cases, when proxy arp cannot work
> correctly.
>
> Alexey
> -
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Hello,
First thank you for your answer. I must enable proxy arp cause I need it with
shaper interface. During configuration in user mode I noticed that kernel
sees shaper device instead of using its device attached (in fact I received
from a lan machine a "IP conflit"): I think that it is more correct to use
the device attached to shaper, for 2 reasons:
1-) shaper is not a "real" interface (I mean directly connected to a wire or
wireless physical interface), while proxy arp sends "ARP REPLY" using
physical devices only.
2-) Proxy arp would become more flexible, also using proxy arp interface:
proxy arp is a great thing, particulary with complex wireless networks. Like
all good thinks I think that we have to keep it under kernel to keep simplify
sysadmin life!
Anyway, there are some applications that need shaper and proxy arp (for
example using a traffic manager behind a firewall).
As I said in my first message, I tested it with 2.4.6 and it "appears" (I
tested it in a very little net) to work well (but I think performance aren't
so well...).
Thank you for your help.
Best regards
Roberto Arcomano
Hello!
> As I said in my first message, I tested it with 2.4.6 and it "appears" (I
> tested it in a very little net) to work well
The patch works right, I think. But it is so utterly ugly and its scope
is so narrow, that I do think this is acceptable.
Actually, you may use CBQ instead it does not create problems of this
kind. Seems, scripts to setup it can be found in LRP. I can send it,
but I am not sure that my copy is the newest.
Alexey
Il 20:54, mercoled? 25 luglio 2001, hai scritto:
> Hello!
>
> > As I said in my first message, I tested it with 2.4.6 and it "appears" (I
> > tested it in a very little net) to work well
>
> The patch works right, I think. But it is so utterly ugly and its scope
> is so narrow, that I do think this is acceptable.
>
> Actually, you may use CBQ instead it does not create problems of this
> kind. Seems, scripts to setup it can be found in LRP. I can send it,
> but I am not sure that my copy is the newest.
>
> Alexey
Please send me script you was talking about.
I know that CBQ is a more recent (and I guess better) method to limit
bandwidth, but I think also there are still many users of "shaper" device who
would want to avoid proxy arp problems.
Thank you for all
Best Regards
Roberto Arcomano