netfilter: flowtable: fast NAT functions never fail

Simplify existing fast NAT routines by returning void. After the
skb_try_make_writable() call consolidation, these routines cannot ever
fail.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 16 insertions, 25 deletions

diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index 3bdbd962a08406..8ffd3f3c288c68 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -389,20 +389,17 @@ static void nf_flow_offload_work_gc(struct work_struct *work)
 	queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
 }
 
-
-static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
-				__be16 port, __be16 new_port)
+static void nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
+				 __be16 port, __be16 new_port)
 {
 	struct tcphdr *tcph;
 
 	tcph = (void *)(skb_network_header(skb) + thoff);
 	inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false);
-
-	return 0;
 }
 
-static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
-				__be16 port, __be16 new_port)
+static void nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
+				 __be16 port, __be16 new_port)
 {
 	struct udphdr *udph;
 
@@ -413,30 +410,24 @@ static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
 		if (!udph->check)
 			udph->check = CSUM_MANGLED_0;
 	}
-
-	return 0;
 }
 
-static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
-			    u8 protocol, __be16 port, __be16 new_port)
+static void nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
+			     u8 protocol, __be16 port, __be16 new_port)
 {
 	switch (protocol) {
 	case IPPROTO_TCP:
-		if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
-			return NF_DROP;
+		nf_flow_nat_port_tcp(skb, thoff, port, new_port);
 		break;
 	case IPPROTO_UDP:
-		if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
-			return NF_DROP;
+		nf_flow_nat_port_udp(skb, thoff, port, new_port);
 		break;
 	}
-
-	return 0;
 }
 
-int nf_flow_snat_port(const struct flow_offload *flow,
-		      struct sk_buff *skb, unsigned int thoff,
-		      u8 protocol, enum flow_offload_tuple_dir dir)
+void nf_flow_snat_port(const struct flow_offload *flow,
+		       struct sk_buff *skb, unsigned int thoff,
+		       u8 protocol, enum flow_offload_tuple_dir dir)
 {
 	struct flow_ports *hdr;
 	__be16 port, new_port;
@@ -456,13 +447,13 @@ int nf_flow_snat_port(const struct flow_offload *flow,
 		break;
 	}
 
-	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
+	nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 }
 EXPORT_SYMBOL_GPL(nf_flow_snat_port);
 
-int nf_flow_dnat_port(const struct flow_offload *flow,
-		      struct sk_buff *skb, unsigned int thoff,
-		      u8 protocol, enum flow_offload_tuple_dir dir)
+void nf_flow_dnat_port(const struct flow_offload *flow, struct sk_buff *skb,
+		       unsigned int thoff, u8 protocol,
+		       enum flow_offload_tuple_dir dir)
 {
 	struct flow_ports *hdr;
 	__be16 port, new_port;
@@ -482,7 +473,7 @@ int nf_flow_dnat_port(const struct flow_offload *flow,
 		break;
 	}
 
-	return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
+	nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 }
 EXPORT_SYMBOL_GPL(nf_flow_dnat_port);