Patchwork [net,v2] ipv6: only static routes qualify for equal cost multipathing

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Submitter Hannes Frederic Sowa
Date July 12, 2013, 2:37 a.m.
Message ID <20130712023731.GE12611@order.stressinduktion.org>
Download mbox | patch
Permalink /patch/258682/
State Superseded
Delegated to: David Miller
Headers show

Comments

Hannes Frederic Sowa - July 12, 2013, 2:37 a.m.
Static routes in this case are non-expiring routes which did not get
configured by autoconf or by icmpv6 redirects.

To make sure we actually get an ecmp route while searching for the first
one in this fib6_node's leafs, also make sure it matches the ecmp route
assumptions.

v2:
a) Removed RTF_EXPIRE check in dst.from chain. The check of RTF_ADDRCONF
   already ensures that this route, even if added manually again without
   RTF_EXPIRES (or RA switches to infinite timeout), does not cause the
   rt6i_nsiblings logic to go wrong if a later RA updates the expiration
   time later.

Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
 net/ipv6/ip6_fib.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
Hannes Frederic Sowa - July 12, 2013, 4:56 p.m.
On Fri, Jul 12, 2013 at 04:37:31AM +0200, Hannes Frederic Sowa wrote:
> Static routes in this case are non-expiring routes which did not get
> configured by autoconf or by icmpv6 redirects.
> 
> To make sure we actually get an ecmp route while searching for the first
> one in this fib6_node's leafs, also make sure it matches the ecmp route
> assumptions.
> 
> v2:
> a) Removed RTF_EXPIRE check in dst.from chain. The check of RTF_ADDRCONF
>    already ensures that this route, even if added manually again without
>    RTF_EXPIRES (or RA switches to infinite timeout), does not cause the
>    rt6i_nsiblings logic to go wrong if a later RA updates the expiration
>    time later.
> 
> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> ---
>  net/ipv6/ip6_fib.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
> index 192dd1a..662b90c 100644
> --- a/net/ipv6/ip6_fib.c
> +++ b/net/ipv6/ip6_fib.c
> @@ -632,6 +632,13 @@ insert_above:
>  	return ln;
>  }
>  
> +static inline bool rt6_qualify_for_ecmp(struct rt6_info *rt)
> +{
> +	return (rt->rt6i_flags &
> +		(RTF_EXPIRES|RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
> +	       RTF_GATEWAY;
> +}

I am in progress to revisit this patch if RTF_EXPIRES is necessary. Please
defer this patch until then.

Thanks,

  Hannes

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Patch

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 192dd1a..662b90c 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -632,6 +632,13 @@  insert_above:
 	return ln;
 }
 
+static inline bool rt6_qualify_for_ecmp(struct rt6_info *rt)
+{
+	return (rt->rt6i_flags &
+		(RTF_EXPIRES|RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
+	       RTF_GATEWAY;
+}
+
 /*
  *	Insert routing information in a node.
  */
@@ -646,6 +653,7 @@  static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 	int add = (!info->nlh ||
 		   (info->nlh->nlmsg_flags & NLM_F_CREATE));
 	int found = 0;
+	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 
 	ins = &fn->leaf;
 
@@ -691,9 +699,8 @@  static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 			 * To avoid long list, we only had siblings if the
 			 * route have a gateway.
 			 */
-			if (rt->rt6i_flags & RTF_GATEWAY &&
-			    !(rt->rt6i_flags & RTF_EXPIRES) &&
-			    !(iter->rt6i_flags & RTF_EXPIRES))
+			if (rt_can_ecmp &&
+			    rt6_qualify_for_ecmp(iter))
 				rt->rt6i_nsiblings++;
 		}
 
@@ -715,7 +722,8 @@  static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 		/* Find the first route that have the same metric */
 		sibling = fn->leaf;
 		while (sibling) {
-			if (sibling->rt6i_metric == rt->rt6i_metric) {
+			if (sibling->rt6i_metric == rt->rt6i_metric &&
+			    rt6_qualify_for_ecmp(sibling)) {
 				list_add_tail(&rt->rt6i_siblings,
 					      &sibling->rt6i_siblings);
 				break;