On 9/16/16 2:33 PM, Vincent Bernat wrote:
> Commit 8c14586fc320 ("net: ipv6: Use passed in table for nexthop
> lookups") introduced a regression: insertion of an IPv6 route in a table
> not containing the appropriate connected route for the gateway but which
> contained a non-connected route (like a default gateway) fails while it
> was previously working:
>
> $ ip link add eth0 type dummy
> $ ip link set up dev eth0
> $ ip addr add 2001:db8::1/64 dev eth0
> $ ip route add ::/0 via 2001:db8::5 dev eth0 table 20
> $ ip route add 2001:db8:cafe::1/128 via 2001:db8::6 dev eth0 table 20
> RTNETLINK answers: No route to host
> $ ip -6 route show table 20
> default via 2001:db8::5 dev eth0 metric 1024 pref medium
>
> After this patch, we get:
>
> $ ip route add 2001:db8:cafe::1/128 via 2001:db8::6 dev eth0 table 20
> $ ip -6 route show table 20
> 2001:db8:cafe::1 via 2001:db8::6 dev eth0 metric 1024 pref medium
> default via 2001:db8::5 dev eth0 metric 1024 pref medium
>
need an explicit Fixes tag here:
Fixes: 8c14586fc320 ("net: ipv6: Use passed in table for nexthop lookups")
> Signed-off-by: Vincent Bernat <vinc...@bernat.im>
> ---
> net/ipv6/route.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index ad4a7ff301fc..2c6c7257ff75 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -1994,6 +1994,14 @@ static struct rt6_info *ip6_route_info_create(struct
> fib6_config *cfg)
> if (cfg->fc_table)
> grt = ip6_nh_lookup_table(net, cfg, gw_addr);
>
> + if (grt) {
> + if (grt->rt6i_flags & RTF_GATEWAY ||
> + (dev && dev != grt->dst.dev)) {
> + ip6_rt_put(grt);
> + grt = NULL;
> + }
> + }
> +
The if grt check needs to be under the 'if (cfg->fc_table)'
> if (!grt)
> grt = rt6_lookup(net, gw_addr, NULL,
> cfg->fc_ifindex, 1);
>
