Date:	Wed, 28 Apr 2010 14:59:40 +0200
From:	Jiri Bohac <jbohac@...e.cz>
To:	Jay Vosburgh <fubar@...ibm.com>
Cc:	bonding-devel@...ts.sourceforge.net, netdev@...r.kernel.org
Subject: [PATCH] bonding: fix arp_validate on bonds inside a bridge

Hi,

bonding with arp_validate does not currently work when the
bonding master is part of a bridge. This is because
bond_arp_rcv() is registered as a packet type handler for ARP,
but before netif_receive_skb() processes the ptype_base hash
table, handle_bridge() is called and changes the skb->dev to
point to the bridge device.

This patch makes bonding_should_drop() call the bonding ARP
handler directly if a IFF_MASTER_NEEDARP flag is set on the
bonding master.  bond_register_arp() now only needs to set the
IFF_MASTER_NEEDARP flag.

We ne longer need special ARP handling for inactive slaves, hence
IFF_SLAVE_NEEDARP is not needed.

skb_reset_network_header() and skb_reset_transport_header() need
to be called before the call to bonding_should_drop() because
bond_handle_arp() needs the offsets initialized.

P.S.: bonding_should_drop() should probably be renamed to
handle_bonding() -- we already have handle_bridge() and
handle_macvlan(), and bonding_should_drop() has long been doing
other stuff than deciding which packets to drop...



Signed-off-by: Jiri Bohac <jbohac@...e.cz>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 0075514..cafd404 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1940,8 +1940,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 	}
 
 	slave_dev->priv_flags &= ~(IFF_MASTER_8023AD | IFF_MASTER_ALB |
-				   IFF_SLAVE_INACTIVE | IFF_BONDING |
-				   IFF_SLAVE_NEEDARP);
+				   IFF_SLAVE_INACTIVE | IFF_BONDING);
 
 	kfree(slave);
 
@@ -2612,11 +2611,12 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
 	}
 }
 
-static int bond_arp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
+static void bond_handle_arp(struct sk_buff *skb)
 {
 	struct arphdr *arp;
 	struct slave *slave;
 	struct bonding *bond;
+	struct net_device *dev = skb->dev->master, *orig_dev = skb->dev;
 	unsigned char *arp_ptr;
 	__be32 sip, tip;
 
@@ -2637,9 +2637,8 @@ static int bond_arp_rcv(struct sk_buff *skb, struct net_device *dev, struct pack
 	bond = netdev_priv(dev);
 	read_lock(&bond->lock);
 
-	pr_debug("bond_arp_rcv: bond %s skb->dev %s orig_dev %s\n",
-		 bond->dev->name, skb->dev ? skb->dev->name : "NULL",
-		 orig_dev ? orig_dev->name : "NULL");
+	pr_debug("bond_handle_arp: bond: %s, master: %s, slave: %s\n",
+		bond->dev->name, dev->name, orig_dev->name);
 
 	slave = bond_get_slave_by_dev(bond, orig_dev);
 	if (!slave || !slave_do_arp_validate(bond, slave))
@@ -2684,8 +2683,7 @@ static int bond_arp_rcv(struct sk_buff *skb, struct net_device *dev, struct pack
 out_unlock:
 	read_unlock(&bond->lock);
 out:
-	dev_kfree_skb(skb);
-	return NET_RX_SUCCESS;
+	return;
 }
 
 /*
@@ -3567,23 +3565,12 @@ static void bond_unregister_lacpdu(struct bonding *bond)
 
 void bond_register_arp(struct bonding *bond)
 {
-	struct packet_type *pt = &bond->arp_mon_pt;
-
-	if (pt->type)
-		return;
-
-	pt->type = htons(ETH_P_ARP);
-	pt->dev = bond->dev;
-	pt->func = bond_arp_rcv;
-	dev_add_pack(pt);
+	bond->dev->priv_flags |= IFF_MASTER_NEEDARP;
 }
 
 void bond_unregister_arp(struct bonding *bond)
 {
-	struct packet_type *pt = &bond->arp_mon_pt;
-
-	dev_remove_pack(pt);
-	pt->type = 0;
+	bond->dev->priv_flags &= ~IFF_MASTER_NEEDARP;
 }
 
 /*---------------------------- Hashing Policies -----------------------------*/
@@ -5041,6 +5028,7 @@ static int __init bonding_init(void)
 	register_netdevice_notifier(&bond_netdev_notifier);
 	register_inetaddr_notifier(&bond_inetaddr_notifier);
 	bond_register_ipv6_notifier();
+	bond_handle_arp_hook = bond_handle_arp;
 out:
 	return res;
 err:
@@ -5061,6 +5049,7 @@ static void __exit bonding_exit(void)
 
 	rtnl_link_unregister(&bond_link_ops);
 	unregister_pernet_subsys(&bond_net_ops);
+	bond_handle_arp_hook = NULL;
 }
 
 module_init(bonding_init);
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 257a7a4..57adfe5 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -212,7 +212,6 @@ struct bonding {
 	struct   bond_params params;
 	struct   list_head vlan_list;
 	struct   vlan_group *vlgrp;
-	struct   packet_type arp_mon_pt;
 	struct   workqueue_struct *wq;
 	struct   delayed_work mii_work;
 	struct   delayed_work arp_work;
@@ -292,14 +291,12 @@ static inline void bond_set_slave_inactive_flags(struct slave *slave)
 	if (!bond_is_lb(bond))
 		slave->state = BOND_STATE_BACKUP;
 	slave->dev->priv_flags |= IFF_SLAVE_INACTIVE;
-	if (slave_do_arp_validate(bond, slave))
-		slave->dev->priv_flags |= IFF_SLAVE_NEEDARP;
 }
 
 static inline void bond_set_slave_active_flags(struct slave *slave)
 {
 	slave->state = BOND_STATE_ACTIVE;
-	slave->dev->priv_flags &= ~(IFF_SLAVE_INACTIVE | IFF_SLAVE_NEEDARP);
+	slave->dev->priv_flags &= ~IFF_SLAVE_INACTIVE;
 }
 
 static inline void bond_set_master_3ad_flags(struct bonding *bond)
diff --git a/include/linux/if.h b/include/linux/if.h
index 3a9f410..84ab2c8 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -63,7 +63,7 @@
 #define IFF_MASTER_8023AD	0x8	/* bonding master, 802.3ad. 	*/
 #define IFF_MASTER_ALB	0x10		/* bonding master, balance-alb.	*/
 #define IFF_BONDING	0x20		/* bonding master or slave	*/
-#define IFF_SLAVE_NEEDARP 0x40		/* need ARPs for validation	*/
+#define IFF_MASTER_NEEDARP 0x40		/* need ARPs for validation	*/
 #define IFF_ISATAP	0x80		/* ISATAP interface (RFC4214)	*/
 #define IFF_MASTER_ARPMON 0x100		/* bonding master, ARP mon in use */
 #define IFF_WAN_HDLC	0x200		/* WAN HDLC device		*/
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index fa8b476..9f82fc6 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2055,6 +2055,8 @@ static inline void skb_bond_set_mac_by_master(struct sk_buff *skb,
 	}
 }
 
+extern void (*bond_handle_arp_hook)(struct sk_buff *skb);
+
 /* On bonding slaves other than the currently active slave, suppress
  * duplicates except for 802.3ad ETH_P_SLOW, alb non-mcast/bcast, and
  * ARP on active-backup slaves with arp_validate enabled.
@@ -2076,11 +2078,13 @@ static inline int skb_bond_should_drop(struct sk_buff *skb,
 			skb_bond_set_mac_by_master(skb, master);
 		}
 
-		if (dev->priv_flags & IFF_SLAVE_INACTIVE) {
-			if ((dev->priv_flags & IFF_SLAVE_NEEDARP) &&
-			    skb->protocol == __cpu_to_be16(ETH_P_ARP))
-				return 0;
+		/* pass ARP frames directly to bonding
+		   before bridging or other hooks change them */
+		if ((master->priv_flags & IFF_MASTER_NEEDARP) &&
+		    skb->protocol == __cpu_to_be16(ETH_P_ARP))
+			bond_handle_arp_hook(skb);
 
+		if (dev->priv_flags & IFF_SLAVE_INACTIVE) {
 			if (master->priv_flags & IFF_MASTER_ALB) {
 				if (skb->pkt_type != PACKET_BROADCAST &&
 				    skb->pkt_type != PACKET_MULTICAST)
diff --git a/net/core/dev.c b/net/core/dev.c
index f769098..98d85a8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2314,6 +2314,9 @@ static inline int deliver_skb(struct sk_buff *skb,
 	return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
 }
 
+void (*bond_handle_arp_hook)(struct sk_buff *skb);
+EXPORT_SYMBOL_GPL(bond_handle_arp_hook);
+
 #if defined(CONFIG_BRIDGE) || defined (CONFIG_BRIDGE_MODULE)
 
 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
@@ -2507,6 +2510,10 @@ int netif_receive_skb(struct sk_buff *skb)
 	if (!skb->skb_iif)
 		skb->skb_iif = skb->dev->ifindex;
 
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+	skb->mac_len = skb->network_header - skb->mac_header;
+
 	null_or_orig = NULL;
 	orig_dev = skb->dev;
 	master = ACCESS_ONCE(orig_dev->master);
@@ -2519,10 +2526,6 @@ int netif_receive_skb(struct sk_buff *skb)
 
 	__get_cpu_var(netdev_rx_stat).total++;
 
-	skb_reset_network_header(skb);
-	skb_reset_transport_header(skb);
-	skb->mac_len = skb->network_header - skb->mac_header;
-
 	pt_prev = NULL;
 
 	rcu_read_lock();


-- 
Jiri Bohac <jbohac@...e.cz>
SUSE Labs, SUSE CZ

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