Patchwork [RFC] ipv6: don't add link local route when there is no link local address

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Submitter Nicolas Dichtel
Date Sept. 26, 2012, 1:09 p.m.
Message ID <1348664962-4018-1-git-send-email-nicolas.dichtel@6wind.com>
Download mbox | patch
Permalink /patch/187078/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Nicolas Dichtel - Sept. 26, 2012, 1:09 p.m.
When an address is added on loopback (ip -6 a a 2002::1/128 dev lo), a route
to fe80::/64 is added in the main table:
  unreachable fe80::/64 dev lo  proto kernel  metric 256  error -101

This route does not match any prefix (no fe80:: address on lo). In fact,
addrconf_dev_config() will not add link local address because this function
filters interfaces by type. If the link local address is added manually, the
route to the link local prefix will be automatically added by
addrconf_add_linklocal().
Note also, that this route is not deleted when the address is removed.

After looking at the code, it seems that addrconf_add_lroute() is redundant with
addrconf_add_linklocal(), because this function will add the link local route
when the link local address is configured.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---
 net/ipv6/addrconf.c | 11 -----------
 1 file changed, 11 deletions(-)
David Miller - Oct. 1, 2012, 8:55 p.m.
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Wed, 26 Sep 2012 15:09:22 +0200

> When an address is added on loopback (ip -6 a a 2002::1/128 dev lo), a route
> to fe80::/64 is added in the main table:
>   unreachable fe80::/64 dev lo  proto kernel  metric 256  error -101
> 
> This route does not match any prefix (no fe80:: address on lo). In fact,
> addrconf_dev_config() will not add link local address because this function
> filters interfaces by type. If the link local address is added manually, the
> route to the link local prefix will be automatically added by
> addrconf_add_linklocal().
> Note also, that this route is not deleted when the address is removed.
> 
> After looking at the code, it seems that addrconf_add_lroute() is redundant with
> addrconf_add_linklocal(), because this function will add the link local route
> when the link local address is configured.
> 
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>

This change looks correct, however:

> @@ -2489,7 +2479,6 @@ static void addrconf_sit_config(struct net_device *dev)
>  
>  	if (dev->flags&IFF_POINTOPOINT) {
>  		addrconf_add_mroute(dev);
> -		addrconf_add_lroute(dev);
>  	} else
>  		sit_route_add(dev);

now that the if() branch is a single statement, please remove the
curly braces.

Thanks.
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Patch

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index ea3e9af..041664b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1782,14 +1782,6 @@  static void sit_route_add(struct net_device *dev)
 }
 #endif
 
-static void addrconf_add_lroute(struct net_device *dev)
-{
-	struct in6_addr addr;
-
-	ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
-	addrconf_prefix_route(&addr, 64, dev, 0, 0);
-}
-
 static struct inet6_dev *addrconf_add_dev(struct net_device *dev)
 {
 	struct inet6_dev *idev;
@@ -1807,8 +1799,6 @@  static struct inet6_dev *addrconf_add_dev(struct net_device *dev)
 	if (!(dev->flags & IFF_LOOPBACK))
 		addrconf_add_mroute(dev);
 
-	/* Add link local route */
-	addrconf_add_lroute(dev);
 	return idev;
 }
 
@@ -2489,7 +2479,6 @@  static void addrconf_sit_config(struct net_device *dev)
 
 	if (dev->flags&IFF_POINTOPOINT) {
 		addrconf_add_mroute(dev);
-		addrconf_add_lroute(dev);
 	} else
 		sit_route_add(dev);
 }