[IPv6] route: Fix prohibit and blackhole routing decision

Lookups resolving to ip6_blk_hole_entry must result in silently
discarding the packets whereas an ip6_pkt_prohibit_entry is
supposed to cause an ICMPV6_ADM_PROHIBITED message to be sent.

Thanks to Kim Nordlund <kim.nordlund@nokia.com> for noticing
this bug.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 6 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index aa96be860e96..5c00ca4fa52c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -94,6 +94,9 @@ static int		 ip6_dst_gc(void);
 
 static int              ip6_pkt_discard(struct sk_buff *skb);
 static int              ip6_pkt_discard_out(struct sk_buff *skb);
+static int              ip6_pkt_prohibit(struct sk_buff *skb);
+static int              ip6_pkt_prohibit_out(struct sk_buff *skb);
+static int              ip6_pkt_blk_hole(struct sk_buff *skb);
 static void             ip6_link_failure(struct sk_buff *skb);
 static void             ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
 
@@ -150,8 +153,8 @@ struct rt6_info ip6_prohibit_entry = {
                         .obsolete       = -1,
                         .error          = -EACCES,
                         .metrics        = { [RTAX_HOPLIMIT - 1] = 255, },
-                        .input          = ip6_pkt_discard,
-                        .output         = ip6_pkt_discard_out,
+                        .input          = ip6_pkt_prohibit,
+                        .output         = ip6_pkt_prohibit_out,
                         .ops            = &ip6_dst_ops,
                         .path           = (struct dst_entry*)&ip6_prohibit_entry,
                 }
@@ -170,8 +173,8 @@ struct rt6_info ip6_blk_hole_entry = {
                         .obsolete       = -1,
                         .error          = -EINVAL,
                         .metrics        = { [RTAX_HOPLIMIT - 1] = 255, },
-                        .input          = ip6_pkt_discard,
-                        .output         = ip6_pkt_discard_out,
+                        .input          = ip6_pkt_blk_hole,
+                        .output         = ip6_pkt_blk_hole,
                         .ops            = &ip6_dst_ops,
                         .path           = (struct dst_entry*)&ip6_blk_hole_entry,
                 }
@@ -1742,24 +1745,46 @@ int ipv6_route_ioctl(unsigned int cmd, void __user *arg)
  *      Drop the packet on the floor
  */
 
-static int ip6_pkt_discard(struct sk_buff *skb)
+static inline int ip6_pkt_drop(struct sk_buff *skb, int code)
 {
         int type = ipv6_addr_type(&skb->nh.ipv6h->daddr);
         if (type == IPV6_ADDR_ANY || type == IPV6_ADDR_RESERVED)
                 IP6_INC_STATS(IPSTATS_MIB_INADDRERRORS);
 
         IP6_INC_STATS(IPSTATS_MIB_OUTNOROUTES);
-        icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_NOROUTE, 0, skb->dev);
+        icmpv6_send(skb, ICMPV6_DEST_UNREACH, code, 0, skb->dev);
         kfree_skb(skb);
         return 0;
 }
 
+static int ip6_pkt_discard(struct sk_buff *skb)
+{
+        return ip6_pkt_drop(skb, ICMPV6_NOROUTE);
+}
+
 static int ip6_pkt_discard_out(struct sk_buff *skb)
 {
         skb->dev = skb->dst->dev;
         return ip6_pkt_discard(skb);
 }
 
+static int ip6_pkt_prohibit(struct sk_buff *skb)
+{
+        return ip6_pkt_drop(skb, ICMPV6_ADM_PROHIBITED);
+}
+
+static int ip6_pkt_prohibit_out(struct sk_buff *skb)
+{
+        skb->dev = skb->dst->dev;
+        return ip6_pkt_prohibit(skb);
+}
+
+static int ip6_pkt_blk_hole(struct sk_buff *skb)
+{
+        kfree_skb(skb);
+        return 0;
+}
+
 /*
  *      Allocate a dst for local (unicast / anycast) address.
  */