[PATCH] net: ipv6: Do not consider link state for nexthop validation

[David Ahern]

Similar to IPv4, do not consider link state when validating next hops.

Currently, if the link is down default routes can fail to insert:
 $ ip -6 ro add vrf blue default via 2100:2::64 dev eth2
 RTNETLINK answers: No route to host

With this patch the command succeeds.

Fixes: 8c14586fc320 ("net: ipv6: Use passed in table for nexthop lookups")
Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
 include/net/ip6_route.h | 1 +
 net/ipv6/route.c        | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index e0cd318d5103..f83e78d071a3 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -32,6 +32,7 @@ struct route_info {
 #define RT6_LOOKUP_F_SRCPREF_TMP       0x00000008
 #define RT6_LOOKUP_F_SRCPREF_PUBLIC    0x00000010
 #define RT6_LOOKUP_F_SRCPREF_COA       0x00000020
+#define RT6_LOOKUP_F_IGNORE_LINKSTATE  0x00000040
 
 /* We do not (yet ?) support IPv6 jumbograms (RFC 2675)
  * Unlike IPv4, hdr->seg_len doesn't include the IPv6 header
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3ac19eb81a86..947ed1ded026 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -658,7 +658,8 @@ static struct rt6_info *find_match(struct rt6_info *rt, int 
oif, int strict,
        struct net_device *dev = rt->dst.dev;
 
        if (dev && !netif_carrier_ok(dev) &&
-           idev->cnf.ignore_routes_with_linkdown)
+           idev->cnf.ignore_routes_with_linkdown &&
+           !(strict & RT6_LOOKUP_F_IGNORE_LINKSTATE))
                goto out;
 
        if (rt6_check_expired(rt))
@@ -1052,6 +1053,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct 
fib6_table *table,
        int strict = 0;
 
        strict |= flags & RT6_LOOKUP_F_IFACE;
+       strict |= flags & RT6_LOOKUP_F_IGNORE_LINKSTATE;
        if (net->ipv6.devconf_all->forwarding == 0)
                strict |= RT6_LOOKUP_F_REACHABLE;
 
@@ -1791,7 +1793,7 @@ static struct rt6_info *ip6_nh_lookup_table(struct net 
*net,
        };
        struct fib6_table *table;
        struct rt6_info *rt;
-       int flags = RT6_LOOKUP_F_IFACE;
+       int flags = RT6_LOOKUP_F_IFACE | RT6_LOOKUP_F_IGNORE_LINKSTATE;
 
        table = fib6_get_table(net, cfg->fc_table);
        if (!table)
-- 
2.1.4