Re: Patch suggestion for proxy arp on shaper interface

[Roberto Arcomano <berto@fatamorgana.com>]

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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




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--- 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)
 					neigh_release(n);