netdev - question on ipv6 support for duplicate nexthops

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <53AB41B3.1020201@cumulusnetworks.com>
Date:	Wed, 25 Jun 2014 14:40:03 -0700
From:	Roopa Prabhu <roopa@...ulusnetworks.com>
To:	netdev <netdev@...r.kernel.org>
CC:	Daniel Walton <dwalton@...ulusnetworks.com>
Subject: question on ipv6 support for duplicate nexthops

ipv4 allows duplicate nexthops. Multiple instances of same
  nexthops maybe used to give higher weights to some nexthops
(though the "weight" attribute can be used for the same purpose).

ipv6 does not seem to support duplicate nexthops.

Example: The below ipv6 route is rejected by the kernel
#ip -6 route add 2001:10:1:3::/64 nexthop via 2001:10:1:2::99 nexthop 
via 2001:10:1:2::99

The below patch points to the code that is preventing the addition of 
duplicate nexthops.

I am not sure yet if there are other side effects to the patch below.
If there is interest in making ipv6 consistent with ipv4 for duplicate 
nexthop handling, i can submit a patch.


diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index cb4459b..afecc87 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -698,20 +698,6 @@ static int fib6_add_rt2node(struct fib6_node *fn, 
struct rt6_info *rt,
                                 break;
                         }

-                       if (iter->dst.dev == rt->dst.dev &&
-                           iter->rt6i_idev == rt->rt6i_idev &&
- ipv6_addr_equal(&iter->rt6i_gateway,
- &rt->rt6i_gateway)) {
-                               if (rt->rt6i_nsiblings)
-                                       rt->rt6i_nsiblings = 0;
-                               if (!(iter->rt6i_flags & RTF_EXPIRES))
-                                       return -EEXIST;
-                               if (!(rt->rt6i_flags & RTF_EXPIRES))
-                                       rt6_clean_expires(iter);
-                               else
-                                       rt6_set_expires(iter, 
rt->dst.expires);
-                               return -EEXIST;
-                       }
                         /* If we have the same destination and the same 
metric,
                          * but not the same gateway, then the route we 
try to
                          * add is sibling to this route, increment our 
counter

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html