net: bridge: remove _deliver functions and consolidate forward code

Before this patch we had two flavors of most forwarding functions -
_forward and _deliver, the difference being that the latter are used
when the packets are locally originated. Instead of all this function
pointer passing and code duplication, we can just pass a boolean noting
that the packet was locally originated and use that to perform the
necessary checks in __br_forward. This gives a minor performance
improvement but more importantly consolidates the forwarding paths.
Also add a kernel doc comment to explain the exported br_forward()'s
arguments.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 65 insertions, 119 deletions

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 204f99304a8a..63a83d8d7da3 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -21,11 +21,6 @@
 #include <linux/netfilter_bridge.h>
 #include "br_private.h"
 
-static int deliver_clone(const struct net_bridge_port *prev,
-			 struct sk_buff *skb,
-			 void (*__packet_hook)(const struct net_bridge_port *p,
-					       struct sk_buff *skb));
-
 /* Don't forward packets to originating port or forwarding disabled */
 static inline int should_deliver(const struct net_bridge_port *p,
 				 const struct sk_buff *skb)
@@ -75,106 +70,92 @@ int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(br_forward_finish);
 
-static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
+static void __br_forward(const struct net_bridge_port *to,
+			 struct sk_buff *skb, bool local_orig)
 {
 	struct net_bridge_vlan_group *vg;
+	struct net_device *indev;
+	struct net *net;
+	int br_hook;
 
 	vg = nbp_vlan_group_rcu(to);
 	skb = br_handle_vlan(to->br, vg, skb);
 	if (!skb)
 		return;
 
+	indev = skb->dev;
 	skb->dev = to->dev;
-
-	if (unlikely(netpoll_tx_running(to->br->dev))) {
-		if (!is_skb_forwardable(skb->dev, skb))
+	if (!local_orig) {
+		if (skb_warn_if_lro(skb)) {
 			kfree_skb(skb);
-		else {
-			skb_push(skb, ETH_HLEN);
-			br_netpoll_send_skb(to, skb);
+			return;
 		}
-		return;
+		br_hook = NF_BR_FORWARD;
+		skb_forward_csum(skb);
+		net = dev_net(indev);
+	} else {
+		if (unlikely(netpoll_tx_running(to->br->dev))) {
+			if (!is_skb_forwardable(skb->dev, skb)) {
+				kfree_skb(skb);
+			} else {
+				skb_push(skb, ETH_HLEN);
+				br_netpoll_send_skb(to, skb);
+			}
+			return;
+		}
+		br_hook = NF_BR_LOCAL_OUT;
+		net = dev_net(skb->dev);
+		indev = NULL;
 	}
 
-	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
-		dev_net(skb->dev), NULL, skb,NULL, skb->dev,
+	NF_HOOK(NFPROTO_BRIDGE, br_hook,
+		net, NULL, skb, indev, skb->dev,
 		br_forward_finish);
 }
 
-static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
+static int deliver_clone(const struct net_bridge_port *prev,
+			 struct sk_buff *skb, bool local_orig)
 {
-	struct net_bridge_vlan_group *vg;
-	struct net_device *indev;
-
-	if (skb_warn_if_lro(skb)) {
-		kfree_skb(skb);
-		return;
-	}
-
-	vg = nbp_vlan_group_rcu(to);
-	skb = br_handle_vlan(to->br, vg, skb);
-	if (!skb)
-		return;
-
-	indev = skb->dev;
-	skb->dev = to->dev;
-	skb_forward_csum(skb);
-
-	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
-		dev_net(indev), NULL, skb, indev, skb->dev,
-		br_forward_finish);
-}
+	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
 
-/* called with rcu_read_lock */
-void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
-{
-	if (to && should_deliver(to, skb)) {
-		__br_deliver(to, skb);
-		return;
+	skb = skb_clone(skb, GFP_ATOMIC);
+	if (!skb) {
+		dev->stats.tx_dropped++;
+		return -ENOMEM;
 	}
 
-	kfree_skb(skb);
+	__br_forward(prev, skb, local_orig);
+	return 0;
 }
-EXPORT_SYMBOL_GPL(br_deliver);
 
-/* called with rcu_read_lock */
-void br_forward(const struct net_bridge_port *to, struct sk_buff *skb,
-		bool local_rcv)
+/**
+ * br_forward - forward a packet to a specific port
+ * @to: destination port
+ * @skb: packet being forwarded
+ * @local_rcv: packet will be received locally after forwarding
+ * @local_orig: packet is locally originated
+ *
+ * Should be called with rcu_read_lock.
+ */
+void br_forward(const struct net_bridge_port *to,
+		struct sk_buff *skb, bool local_rcv, bool local_orig)
 {
 	if (to && should_deliver(to, skb)) {
 		if (local_rcv)
-			deliver_clone(to, skb, __br_forward);
+			deliver_clone(to, skb, local_orig);
 		else
-			__br_forward(to, skb);
+			__br_forward(to, skb, local_orig);
 		return;
 	}
 
 	if (!local_rcv)
 		kfree_skb(skb);
 }
-
-static int deliver_clone(const struct net_bridge_port *prev,
-			 struct sk_buff *skb,
-			 void (*__packet_hook)(const struct net_bridge_port *p,
-					       struct sk_buff *skb))
-{
-	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
-
-	skb = skb_clone(skb, GFP_ATOMIC);
-	if (!skb) {
-		dev->stats.tx_dropped++;
-		return -ENOMEM;
-	}
-
-	__packet_hook(prev, skb);
-	return 0;
-}
+EXPORT_SYMBOL_GPL(br_forward);
 
 static struct net_bridge_port *maybe_deliver(
 	struct net_bridge_port *prev, struct net_bridge_port *p,
-	struct sk_buff *skb,
-	void (*__packet_hook)(const struct net_bridge_port *p,
-			      struct sk_buff *skb))
+	struct sk_buff *skb, bool local_orig)
 {
 	int err;
 
@@ -184,7 +165,7 @@ static struct net_bridge_port *maybe_deliver(
 	if (!prev)
 		goto out;
 
-	err = deliver_clone(prev, skb, __packet_hook);
+	err = deliver_clone(prev, skb, local_orig);
 	if (err)
 		return ERR_PTR(err);
 
@@ -192,18 +173,14 @@ out:
 	return p;
 }
 
-/* called under bridge lock */
-static void br_flood(struct net_bridge *br, struct sk_buff *skb,
-		     void (*__packet_hook)(const struct net_bridge_port *p,
-					   struct sk_buff *skb),
-		     bool local_rcv, bool unicast)
+/* called under rcu_read_lock */
+void br_flood(struct net_bridge *br, struct sk_buff *skb,
+	      bool unicast, bool local_rcv, bool local_orig)
 {
 	u8 igmp_type = br_multicast_igmp_type(skb);
-	struct net_bridge_port *prev;
+	struct net_bridge_port *prev = NULL;
 	struct net_bridge_port *p;
 
-	prev = NULL;
-
 	list_for_each_entry_rcu(p, &br->port_list, list) {
 		/* Do not flood unicast traffic to ports that turn it off */
 		if (unicast && !(p->flags & BR_FLOOD))
@@ -216,7 +193,7 @@ static void br_flood(struct net_bridge *br, struct sk_buff *skb,
 		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
 			continue;
 
-		prev = maybe_deliver(prev, p, skb, __packet_hook);
+		prev = maybe_deliver(prev, p, skb, local_orig);
 		if (IS_ERR(prev))
 			goto out;
 		if (prev == p)
@@ -228,9 +205,9 @@ static void br_flood(struct net_bridge *br, struct sk_buff *skb,
 		goto out;
 
 	if (local_rcv)
-		deliver_clone(prev, skb, __packet_hook);
+		deliver_clone(prev, skb, local_orig);
 	else
-		__packet_hook(prev, skb);
+		__br_forward(prev, skb, local_orig);
 	return;
 
 out:
@@ -238,28 +215,11 @@ out:
 		kfree_skb(skb);
 }
 
-
-/* called with rcu_read_lock */
-void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
-{
-	br_flood(br, skb, __br_deliver, false, unicast);
-}
-
-/* called under bridge lock */
-void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
-		      bool local_rcv, bool unicast)
-{
-	br_flood(br, skb, __br_forward, local_rcv, unicast);
-}
-
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 /* called with rcu_read_lock */
-static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
-			       struct sk_buff *skb,
-			       void (*__packet_hook)(
-					const struct net_bridge_port *p,
-					struct sk_buff *skb),
-			       bool local_rcv)
+void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
+			struct sk_buff *skb,
+			bool local_rcv, bool local_orig)
 {
 	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
 	u8 igmp_type = br_multicast_igmp_type(skb);
@@ -280,7 +240,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 		port = (unsigned long)lport > (unsigned long)rport ?
 		       lport : rport;
 
-		prev = maybe_deliver(prev, port, skb, __packet_hook);
+		prev = maybe_deliver(prev, port, skb, local_orig);
 		if (IS_ERR(prev))
 			goto out;
 		if (prev == port)
@@ -297,27 +257,13 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 		goto out;
 
 	if (local_rcv)
-		deliver_clone(prev, skb, __packet_hook);
+		deliver_clone(prev, skb, local_orig);
 	else
-		__packet_hook(prev, skb);
+		__br_forward(prev, skb, local_orig);
 	return;
 
 out:
 	if (!local_rcv)
 		kfree_skb(skb);
 }
-
-/* called with rcu_read_lock */
-void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
-			  struct sk_buff *skb)
-{
-	br_multicast_flood(mdst, skb, __br_deliver, false);
-}
-
-/* called with rcu_read_lock */
-void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
-			  struct sk_buff *skb, bool local_rcv)
-{
-	br_multicast_flood(mdst, skb, __br_forward, local_rcv);
-}
 #endif