net: Consolidate common blackhole dst ops

[ Upstream commit c4c877b2732466b4c63217baad05c96f775912c7 ]

Move generic blackhole dst ops to the core and use them from both
ipv4_dst_blackhole_ops and ip6_dst_blackhole_ops where possible. No
functional change otherwise. We need these also in other locations
and having to define them over and over again is not great.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

3 files changed, 55 insertions, 64 deletions

diff --git a/net/core/dst.c b/net/core/dst.c
index 0c01bd8d9d81..5f6315601776 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -237,6 +237,44 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
 }
 EXPORT_SYMBOL(__dst_destroy_metrics_generic);
 
+struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie)
+{
+	return NULL;
+}
+
+u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old)
+{
+	return NULL;
+}
+
+struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
+					     struct sk_buff *skb,
+					     const void *daddr)
+{
+	return NULL;
+}
+
+void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
+			       struct sk_buff *skb, u32 mtu,
+			       bool confirm_neigh)
+{
+}
+EXPORT_SYMBOL_GPL(dst_blackhole_update_pmtu);
+
+void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
+			    struct sk_buff *skb)
+{
+}
+EXPORT_SYMBOL_GPL(dst_blackhole_redirect);
+
+unsigned int dst_blackhole_mtu(const struct dst_entry *dst)
+{
+	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
+
+	return mtu ? : dst->dev->mtu;
+}
+EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
+
 static struct dst_ops md_dst_ops = {
 	.family =		AF_UNSPEC,
 };
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9f43abeac3a8..50a6d935376f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2682,44 +2682,15 @@ out:
 	return rth;
 }
 
-static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
-{
-	return NULL;
-}
-
-static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
-{
-	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
-
-	return mtu ? : dst->dev->mtu;
-}
-
-static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
-					  struct sk_buff *skb, u32 mtu,
-					  bool confirm_neigh)
-{
-}
-
-static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
-				       struct sk_buff *skb)
-{
-}
-
-static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
-					  unsigned long old)
-{
-	return NULL;
-}
-
 static struct dst_ops ipv4_dst_blackhole_ops = {
-	.family			=	AF_INET,
-	.check			=	ipv4_blackhole_dst_check,
-	.mtu			=	ipv4_blackhole_mtu,
-	.default_advmss		=	ipv4_default_advmss,
-	.update_pmtu		=	ipv4_rt_blackhole_update_pmtu,
-	.redirect		=	ipv4_rt_blackhole_redirect,
-	.cow_metrics		=	ipv4_rt_blackhole_cow_metrics,
-	.neigh_lookup		=	ipv4_neigh_lookup,
+	.family			= AF_INET,
+	.default_advmss		= ipv4_default_advmss,
+	.neigh_lookup		= ipv4_neigh_lookup,
+	.check			= dst_blackhole_check,
+	.cow_metrics		= dst_blackhole_cow_metrics,
+	.update_pmtu		= dst_blackhole_update_pmtu,
+	.redirect		= dst_blackhole_redirect,
+	.mtu			= dst_blackhole_mtu,
 };
 
 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 7e0ce7af8234..fa276448d5a2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -258,34 +258,16 @@ static struct dst_ops ip6_dst_ops_template = {
 	.confirm_neigh		=	ip6_confirm_neigh,
 };
 
-static unsigned int ip6_blackhole_mtu(const struct dst_entry *dst)
-{
-	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
-
-	return mtu ? : dst->dev->mtu;
-}
-
-static void ip6_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
-					 struct sk_buff *skb, u32 mtu,
-					 bool confirm_neigh)
-{
-}
-
-static void ip6_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
-				      struct sk_buff *skb)
-{
-}
-
 static struct dst_ops ip6_dst_blackhole_ops = {
-	.family			=	AF_INET6,
-	.destroy		=	ip6_dst_destroy,
-	.check			=	ip6_dst_check,
-	.mtu			=	ip6_blackhole_mtu,
-	.default_advmss		=	ip6_default_advmss,
-	.update_pmtu		=	ip6_rt_blackhole_update_pmtu,
-	.redirect		=	ip6_rt_blackhole_redirect,
-	.cow_metrics		=	dst_cow_metrics_generic,
-	.neigh_lookup		=	ip6_dst_neigh_lookup,
+	.family			= AF_INET6,
+	.default_advmss		= ip6_default_advmss,
+	.neigh_lookup		= ip6_dst_neigh_lookup,
+	.check			= ip6_dst_check,
+	.destroy		= ip6_dst_destroy,
+	.cow_metrics		= dst_cow_metrics_generic,
+	.update_pmtu		= dst_blackhole_update_pmtu,
+	.redirect		= dst_blackhole_redirect,
+	.mtu			= dst_blackhole_mtu,
 };
 
 static const u32 ip6_template_metrics[RTAX_MAX] = {