diff mbox

[net-next-2.6] net: replace hooks in __netif_receive_skb V5

Message ID 20100602075207.GD2603@psychotron.redhat.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Jiri Pirko June 2, 2010, 7:52 a.m. UTC 
What this patch does is it removes two receive frame hooks (for bridge and for
macvlan) from __netif_receive_skb. These are replaced them with a single
hook for both. It only supports one hook per device because it makes no
sense to do bridging and macvlan on the same device.

Then a network driver (of virtual netdev like macvlan or bridge) can register
an rx_handler for needed net device.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
---
v4->v5
	- do rcu_assign_pointer even for assigning null for rcu-protected
	  pointers 
	- cosmetics (renames, comments and __netif_receive_skb if part)

 drivers/net/macvlan.c      |   19 +++++--
 include/linux/if_bridge.h  |    2 -
 include/linux/if_macvlan.h |    4 --
 include/linux/netdevice.h  |    7 +++
 net/bridge/br.c            |    2 -
 net/bridge/br_if.c         |    8 +++
 net/bridge/br_input.c      |   12 +++-
 net/bridge/br_private.h    |    3 +-
 net/core/dev.c             |  119 ++++++++++++++++++++-----------------------
 9 files changed, 93 insertions(+), 83 deletions(-)

Comments

David Miller June 2, 2010, 2:11 p.m. UTC | #1 
From: Jiri Pirko <jpirko@redhat.com>
Date: Wed, 2 Jun 2010 09:52:08 +0200

> What this patch does is it removes two receive frame hooks (for bridge and for
> macvlan) from __netif_receive_skb. These are replaced them with a single
> hook for both. It only supports one hook per device because it makes no
> sense to do bridging and macvlan on the same device.
> 
> Then a network driver (of virtual netdev like macvlan or bridge) can register
> an rx_handler for needed net device.
> 
> Signed-off-by: Jiri Pirko <jpirko@redhat.com>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

Ok, this looks good to me.  Applied, thanks everyone.
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stephen hemminger June 2, 2010, 3:07 p.m. UTC | #2 
On Wed, 2 Jun 2010 09:52:08 +0200
Jiri Pirko <jpirko@redhat.com> wrote:

> +
> +	err = netdev_rx_handler_register(dev, macvlan_handle_frame);
> +	if (err) {
> +		rcu_assign_pointer(dev->macvlan_port, NULL);
> +		kfree(port);
> +	}
> +
> +	return err;
>  }

Rcu assign is not necessary here for because the hook didn't
get registered so there is no way for other CPU to see it.
Eric Dumazet June 2, 2010, 3:15 p.m. UTC | #3 
Le mercredi 02 juin 2010 à 08:07 -0700, Stephen Hemminger a écrit :
> On Wed, 2 Jun 2010 09:52:08 +0200
> Jiri Pirko <jpirko@redhat.com> wrote:
> 
> > +
> > +	err = netdev_rx_handler_register(dev, macvlan_handle_frame);
> > +	if (err) {
> > +		rcu_assign_pointer(dev->macvlan_port, NULL);
> > +		kfree(port);
> > +	}
> > +
> > +	return err;
> >  }
> 
> Rcu assign is not necessary here for because the hook didn't
> get registered so there is no way for other CPU to see it.
> 

Thats a valid point, but we should use it, and not care of this litle
detail. Compiler generates same code anyway, since NULL value is tested
by rcu_assign_pointer().

If we dont use rcu_assign_pointer() ourself, Paul or Arnd will put it
one day or another :)

http://lkml.org/lkml/2010/6/1/290



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Fischer, Anna June 2, 2010, 4:20 p.m. UTC | #4 
> Subject: [PATCH net-next-2.6] net: replace hooks in __netif_receive_skb
> V5
> 
> What this patch does is it removes two receive frame hooks (for bridge
> and for
> macvlan) from __netif_receive_skb. These are replaced them with a single
> hook for both. It only supports one hook per device because it makes no
> sense to do bridging and macvlan on the same device.
> 
> Then a network driver (of virtual netdev like macvlan or bridge) can
> register
> an rx_handler for needed net device.
> 
> Signed-off-by: Jiri Pirko <jpirko@redhat.com>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

I would like to see this being accepted. As mentioned before I would love to be able to support multiple receive frame hooks per device, but I think this is a good start.

I think especially with virtualization coming into Linux and new network virtualization approaches being developed it would be nice to have a more generic function for packet receive handlers to hook into the network stack more cleanly. Current approaches rely on 'misusing' the bridging hook into the kernel, because the packet 'sniffing' hooks (via dev_pack_add()) do not give enough control over packet processing.

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Paul E. McKenney June 2, 2010, 8:43 p.m. UTC | #5 
On Wed, Jun 02, 2010 at 05:15:22PM +0200, Eric Dumazet wrote:
> Le mercredi 02 juin 2010 à 08:07 -0700, Stephen Hemminger a écrit :
> > On Wed, 2 Jun 2010 09:52:08 +0200
> > Jiri Pirko <jpirko@redhat.com> wrote:
> > 
> > > +
> > > +	err = netdev_rx_handler_register(dev, macvlan_handle_frame);
> > > +	if (err) {
> > > +		rcu_assign_pointer(dev->macvlan_port, NULL);
> > > +		kfree(port);
> > > +	}
> > > +
> > > +	return err;
> > >  }
> > 
> > Rcu assign is not necessary here for because the hook didn't
> > get registered so there is no way for other CPU to see it.
> > 
> 
> Thats a valid point, but we should use it, and not care of this litle
> detail. Compiler generates same code anyway, since NULL value is tested
> by rcu_assign_pointer().
> 
> If we dont use rcu_assign_pointer() ourself, Paul or Arnd will put it
> one day or another :)
> 
> http://lkml.org/lkml/2010/6/1/290

Some year soon, I hope.  ;-)

							Thanx, Paul
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diff mbox

Patch

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 87e8d4c..53422ce 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -145,15 +145,16 @@  static void macvlan_broadcast(struct sk_buff *skb,
 }
 
 /* called under rcu_read_lock() from netif_receive_skb */
-static struct sk_buff *macvlan_handle_frame(struct macvlan_port *port,
-					    struct sk_buff *skb)
+static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
 {
+	struct macvlan_port *port;
 	const struct ethhdr *eth = eth_hdr(skb);
 	const struct macvlan_dev *vlan;
 	const struct macvlan_dev *src;
 	struct net_device *dev;
 	unsigned int len;
 
+	port = rcu_dereference(skb->dev->macvlan_port);
 	if (is_multicast_ether_addr(eth->h_dest)) {
 		src = macvlan_hash_lookup(port, eth->h_source);
 		if (!src)
@@ -515,6 +516,7 @@  static int macvlan_port_create(struct net_device *dev)
 {
 	struct macvlan_port *port;
 	unsigned int i;
+	int err;
 
 	if (dev->type != ARPHRD_ETHER || dev->flags & IFF_LOOPBACK)
 		return -EINVAL;
@@ -528,13 +530,21 @@  static int macvlan_port_create(struct net_device *dev)
 	for (i = 0; i < MACVLAN_HASH_SIZE; i++)
 		INIT_HLIST_HEAD(&port->vlan_hash[i]);
 	rcu_assign_pointer(dev->macvlan_port, port);
-	return 0;
+
+	err = netdev_rx_handler_register(dev, macvlan_handle_frame);
+	if (err) {
+		rcu_assign_pointer(dev->macvlan_port, NULL);
+		kfree(port);
+	}
+
+	return err;
 }
 
 static void macvlan_port_destroy(struct net_device *dev)
 {
 	struct macvlan_port *port = dev->macvlan_port;
 
+	netdev_rx_handler_unregister(dev);
 	rcu_assign_pointer(dev->macvlan_port, NULL);
 	synchronize_rcu();
 	kfree(port);
@@ -767,14 +777,12 @@  static int __init macvlan_init_module(void)
 	int err;
 
 	register_netdevice_notifier(&macvlan_notifier_block);
-	macvlan_handle_frame_hook = macvlan_handle_frame;
 
 	err = macvlan_link_register(&macvlan_link_ops);
 	if (err < 0)
 		goto err1;
 	return 0;
 err1:
-	macvlan_handle_frame_hook = NULL;
 	unregister_netdevice_notifier(&macvlan_notifier_block);
 	return err;
 }
@@ -782,7 +790,6 @@  err1:
 static void __exit macvlan_cleanup_module(void)
 {
 	rtnl_link_unregister(&macvlan_link_ops);
-	macvlan_handle_frame_hook = NULL;
 	unregister_netdevice_notifier(&macvlan_notifier_block);
 }
 
diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 938b7e8..0d241a5 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -102,8 +102,6 @@  struct __fdb_entry {
 #include <linux/netdevice.h>
 
 extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));
-extern struct sk_buff *(*br_handle_frame_hook)(struct net_bridge_port *p,
-					       struct sk_buff *skb);
 extern int (*br_should_route_hook)(struct sk_buff *skb);
 
 #endif
diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
index 9ea047a..c26a0e4 100644
--- a/include/linux/if_macvlan.h
+++ b/include/linux/if_macvlan.h
@@ -84,8 +84,4 @@  extern int macvlan_link_register(struct rtnl_link_ops *ops);
 extern netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
 				      struct net_device *dev);
 
-
-extern struct sk_buff *(*macvlan_handle_frame_hook)(struct macvlan_port *,
-						    struct sk_buff *);
-
 #endif /* _LINUX_IF_MACVLAN_H */
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a249161..244494f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -381,6 +381,8 @@  enum gro_result {
 };
 typedef enum gro_result gro_result_t;
 
+typedef struct sk_buff *rx_handler_func_t(struct sk_buff *skb);
+
 extern void __napi_schedule(struct napi_struct *n);
 
 static inline int napi_disable_pending(struct napi_struct *n)
@@ -957,6 +959,7 @@  struct net_device {
 #endif
 
 	struct netdev_queue	rx_queue;
+	rx_handler_func_t	*rx_handler;
 
 	struct netdev_queue	*_tx ____cacheline_aligned_in_smp;
 
@@ -1693,6 +1696,10 @@  static inline void napi_free_frags(struct napi_struct *napi)
 	napi->skb = NULL;
 }
 
+extern int netdev_rx_handler_register(struct net_device *dev,
+				      rx_handler_func_t *rx_handler);
+extern void netdev_rx_handler_unregister(struct net_device *dev);
+
 extern void		netif_nit_deliver(struct sk_buff *skb);
 extern int		dev_valid_name(const char *name);
 extern int		dev_ioctl(struct net *net, unsigned int cmd, void __user *);
diff --git a/net/bridge/br.c b/net/bridge/br.c
index 76357b5..c8436fa 100644
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -63,7 +63,6 @@  static int __init br_init(void)
 		goto err_out4;
 
 	brioctl_set(br_ioctl_deviceless_stub);
-	br_handle_frame_hook = br_handle_frame;
 
 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
 	br_fdb_test_addr_hook = br_fdb_test_addr;
@@ -100,7 +99,6 @@  static void __exit br_deinit(void)
 	br_fdb_test_addr_hook = NULL;
 #endif
 
-	br_handle_frame_hook = NULL;
 	br_fdb_fini();
 }
 
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 18b245e..d924234 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -147,6 +147,7 @@  static void del_nbp(struct net_bridge_port *p)
 
 	list_del_rcu(&p->list);
 
+	netdev_rx_handler_unregister(dev);
 	rcu_assign_pointer(dev->br_port, NULL);
 
 	br_multicast_del_port(p);
@@ -429,6 +430,11 @@  int br_add_if(struct net_bridge *br, struct net_device *dev)
 		goto err2;
 
 	rcu_assign_pointer(dev->br_port, p);
+
+	err = netdev_rx_handler_register(dev, br_handle_frame);
+	if (err)
+		goto err3;
+
 	dev_disable_lro(dev);
 
 	list_add_rcu(&p->list, &br->port_list);
@@ -451,6 +457,8 @@  int br_add_if(struct net_bridge *br, struct net_device *dev)
 	br_netpoll_enable(br, dev);
 
 	return 0;
+err3:
+	rcu_assign_pointer(dev->br_port, NULL);
 err2:
 	br_fdb_delete_by_port(br, p, 1);
 err1:
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index d36e700..99647d8 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -131,15 +131,19 @@  static inline int is_link_local(const unsigned char *dest)
 }
 
 /*
- * Called via br_handle_frame_hook.
  * Return NULL if skb is handled
- * note: already called with rcu_read_lock (preempt_disabled)
+ * note: already called with rcu_read_lock (preempt_disabled) from
+ * netif_receive_skb
  */
-struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
+struct sk_buff *br_handle_frame(struct sk_buff *skb)
 {
+	struct net_bridge_port *p;
 	const unsigned char *dest = eth_hdr(skb)->h_dest;
 	int (*rhook)(struct sk_buff *skb);
 
+	if (skb->pkt_type == PACKET_LOOPBACK)
+		return skb;
+
 	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
 		goto drop;
 
@@ -147,6 +151,8 @@  struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
 	if (!skb)
 		return NULL;
 
+	p = rcu_dereference(skb->dev->br_port);
+
 	if (unlikely(is_link_local(dest))) {
 		/* Pause frames shouldn't be passed up by driver anyway */
 		if (skb->protocol == htons(ETH_P_PAUSE))
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 0f4a74b..c83519b 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -331,8 +331,7 @@  extern void br_features_recompute(struct net_bridge *br);
 
 /* br_input.c */
 extern int br_handle_frame_finish(struct sk_buff *skb);
-extern struct sk_buff *br_handle_frame(struct net_bridge_port *p,
-				       struct sk_buff *skb);
+extern struct sk_buff *br_handle_frame(struct sk_buff *skb);
 
 /* br_ioctl.c */
 extern int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
diff --git a/net/core/dev.c b/net/core/dev.c
index 983a3c1..4a02b58 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2583,70 +2583,14 @@  static inline int deliver_skb(struct sk_buff *skb,
 	return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
 }
 
-#if defined(CONFIG_BRIDGE) || defined (CONFIG_BRIDGE_MODULE)
-
-#if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
+#if (defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)) && \
+    (defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE))
 /* This hook is defined here for ATM LANE */
 int (*br_fdb_test_addr_hook)(struct net_device *dev,
 			     unsigned char *addr) __read_mostly;
 EXPORT_SYMBOL_GPL(br_fdb_test_addr_hook);
 #endif
 
-/*
- * If bridge module is loaded call bridging hook.
- *  returns NULL if packet was consumed.
- */
-struct sk_buff *(*br_handle_frame_hook)(struct net_bridge_port *p,
-					struct sk_buff *skb) __read_mostly;
-EXPORT_SYMBOL_GPL(br_handle_frame_hook);
-
-static inline struct sk_buff *handle_bridge(struct sk_buff *skb,
-					    struct packet_type **pt_prev, int *ret,
-					    struct net_device *orig_dev)
-{
-	struct net_bridge_port *port;
-
-	if (skb->pkt_type == PACKET_LOOPBACK ||
-	    (port = rcu_dereference(skb->dev->br_port)) == NULL)
-		return skb;
-
-	if (*pt_prev) {
-		*ret = deliver_skb(skb, *pt_prev, orig_dev);
-		*pt_prev = NULL;
-	}
-
-	return br_handle_frame_hook(port, skb);
-}
-#else
-#define handle_bridge(skb, pt_prev, ret, orig_dev)	(skb)
-#endif
-
-#if defined(CONFIG_MACVLAN) || defined(CONFIG_MACVLAN_MODULE)
-struct sk_buff *(*macvlan_handle_frame_hook)(struct macvlan_port *p,
-					     struct sk_buff *skb) __read_mostly;
-EXPORT_SYMBOL_GPL(macvlan_handle_frame_hook);
-
-static inline struct sk_buff *handle_macvlan(struct sk_buff *skb,
-					     struct packet_type **pt_prev,
-					     int *ret,
-					     struct net_device *orig_dev)
-{
-	struct macvlan_port *port;
-
-	port = rcu_dereference(skb->dev->macvlan_port);
-	if (!port)
-		return skb;
-
-	if (*pt_prev) {
-		*ret = deliver_skb(skb, *pt_prev, orig_dev);
-		*pt_prev = NULL;
-	}
-	return macvlan_handle_frame_hook(port, skb);
-}
-#else
-#define handle_macvlan(skb, pt_prev, ret, orig_dev)	(skb)
-#endif
-
 #ifdef CONFIG_NET_CLS_ACT
 /* TODO: Maybe we should just force sch_ingress to be compiled in
  * when CONFIG_NET_CLS_ACT is? otherwise some useless instructions
@@ -2742,6 +2686,47 @@  void netif_nit_deliver(struct sk_buff *skb)
 	rcu_read_unlock();
 }
 
+/**
+ *	netdev_rx_handler_register - register receive handler
+ *	@dev: device to register a handler for
+ *	@rx_handler: receive handler to register
+ *
+ *	Register a receive hander for a device. This handler will then be
+ *	called from __netif_receive_skb. A negative errno code is returned
+ *	on a failure.
+ *
+ *	The caller must hold the rtnl_mutex.
+ */
+int netdev_rx_handler_register(struct net_device *dev,
+			       rx_handler_func_t *rx_handler)
+{
+	ASSERT_RTNL();
+
+	if (dev->rx_handler)
+		return -EBUSY;
+
+	rcu_assign_pointer(dev->rx_handler, rx_handler);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(netdev_rx_handler_register);
+
+/**
+ *	netdev_rx_handler_unregister - unregister receive handler
+ *	@dev: device to unregister a handler from
+ *
+ *	Unregister a receive hander from a device.
+ *
+ *	The caller must hold the rtnl_mutex.
+ */
+void netdev_rx_handler_unregister(struct net_device *dev)
+{
+
+	ASSERT_RTNL();
+	rcu_assign_pointer(dev->rx_handler, NULL);
+}
+EXPORT_SYMBOL_GPL(netdev_rx_handler_unregister);
+
 static inline void skb_bond_set_mac_by_master(struct sk_buff *skb,
 					      struct net_device *master)
 {
@@ -2794,6 +2779,7 @@  EXPORT_SYMBOL(__skb_bond_should_drop);
 static int __netif_receive_skb(struct sk_buff *skb)
 {
 	struct packet_type *ptype, *pt_prev;
+	rx_handler_func_t *rx_handler;
 	struct net_device *orig_dev;
 	struct net_device *master;
 	struct net_device *null_or_orig;
@@ -2856,12 +2842,17 @@  static int __netif_receive_skb(struct sk_buff *skb)
 ncls:
 #endif
 
-	skb = handle_bridge(skb, &pt_prev, &ret, orig_dev);
-	if (!skb)
-		goto out;
-	skb = handle_macvlan(skb, &pt_prev, &ret, orig_dev);
-	if (!skb)
-		goto out;
+	/* Handle special case of bridge or macvlan */
+	rx_handler = rcu_dereference(skb->dev->rx_handler);
+	if (rx_handler) {
+		if (pt_prev) {
+			ret = deliver_skb(skb, pt_prev, orig_dev);
+			pt_prev = NULL;
+		}
+		skb = rx_handler(skb);
+		if (!skb)
+			goto out;
+	}
 
 	/*
 	 * Make sure frames received on VLAN interfaces stacked on