ipv6: fix handling of blackhole and prohibit routes

When adding a blackhole or a prohibit route, they were handling like classic
routes. Moreover, it was only possible to add this kind of routes by specifying
an interface.

Bug already reported here:
  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=498498

Before the patch:
  $ ip route add blackhole 2001::1/128
  RTNETLINK answers: No such device
  $ ip route add blackhole 2001::1/128 dev eth0
  $ ip -6 route | grep 2001
  2001::1 dev eth0  metric 1024

After:
  $ ip route add blackhole 2001::1/128
  $ ip -6 route | grep 2001
  blackhole 2001::1 dev lo  metric 1024  error -22

v2: wrong patch
v3: add a field fc_type in struct fib6_config to store RTN_* type

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 4 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 0ddf2d132e7f..fa264447a751 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1463,8 +1463,18 @@ int ip6_route_add(struct fib6_config *cfg)
                 }
                 rt->dst.output = ip6_pkt_discard_out;
                 rt->dst.input = ip6_pkt_discard;
-                rt->dst.error = -ENETUNREACH;
                 rt->rt6i_flags = RTF_REJECT|RTF_NONEXTHOP;
+                switch (cfg->fc_type) {
+                case RTN_BLACKHOLE:
+                        rt->dst.error = -EINVAL;
+                        break;
+                case RTN_PROHIBIT:
+                        rt->dst.error = -EACCES;
+                        break;
+                default:
+                        rt->dst.error = -ENETUNREACH;
+                        break;
+                }
                 goto install_route;
         }
 
@@ -2261,8 +2271,11 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
         cfg->fc_src_len = rtm->rtm_src_len;
         cfg->fc_flags = RTF_UP;
         cfg->fc_protocol = rtm->rtm_protocol;
+        cfg->fc_type = rtm->rtm_type;
 
-        if (rtm->rtm_type == RTN_UNREACHABLE)
+        if (rtm->rtm_type == RTN_UNREACHABLE ||
+            rtm->rtm_type == RTN_BLACKHOLE ||
+            rtm->rtm_type == RTN_PROHIBIT)
                 cfg->fc_flags |= RTF_REJECT;
 
         if (rtm->rtm_type == RTN_LOCAL)
@@ -2391,8 +2404,19 @@ static int rt6_fill_node(struct net *net,
         rtm->rtm_table = table;
         if (nla_put_u32(skb, RTA_TABLE, table))
                 goto nla_put_failure;
-        if (rt->rt6i_flags & RTF_REJECT)
-                rtm->rtm_type = RTN_UNREACHABLE;
+        if (rt->rt6i_flags & RTF_REJECT) {
+                switch (rt->dst.error) {
+                case -EINVAL:
+                        rtm->rtm_type = RTN_BLACKHOLE;
+                        break;
+                case -EACCES:
+                        rtm->rtm_type = RTN_PROHIBIT;
+                        break;
+                default:
+                        rtm->rtm_type = RTN_UNREACHABLE;
+                        break;
+                }
+        }
         else if (rt->rt6i_flags & RTF_LOCAL)
                 rtm->rtm_type = RTN_LOCAL;
         else if (rt->dst.dev && (rt->dst.dev->flags & IFF_LOOPBACK))