Date:	Thu, 23 Apr 2009 07:59:41 -0700
From:	Jay Vosburgh <fubar@...ibm.com>
To:	Jiri Pirko <jpirko@...hat.com>
cc:	stefan novak <lms.brubaker@...il.com>,
	Eric Dumazet <dada1@...mosbay.com>,
	linux-kernel@...r.kernel.org,
	Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: bond interface arp, vlan and trunk / network question

Jiri Pirko <jpirko@...hat.com> wrote:

>Thu, Apr 23, 2009 at 03:12:29AM CEST, fubar@...ibm.com wrote:
>>stefan novak <lms.brubaker@...il.com> wrote:
>>
>>>so its a bug in kernel?
>>
>>	Yes.  I think the following patch should add support for
>>arp_validate over VLANs, could you test this?  This is still a work in
>>progress, so it's pretty rough around the edges, but the core
>>functionality should be there.
>>
>>	This works by moving the skb_bond_should_drop logic around, and
>>replaces the current inline code with a hook into bonding to do all of
>>that, plus additional logic.  The reason for a hook is to get the
>>skb_bond_should_drop callers from the VLAN input path before the input
>>device is assigned to the VLAN device.
>>
>>	-J
>>
>>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>>index 99610f3..cc367a3 100644
>>--- a/drivers/net/bonding/bond_main.c
>>+++ b/drivers/net/bonding/bond_main.c
>>@@ -1607,6 +1607,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>> 	read_lock(&bond->lock);
>> 
>> 	new_slave->last_arp_rx = jiffies;
>>+	bond_fix_slave_validate_flag(bond, new_slave);
>> 
>> 	if (bond->params.miimon && !bond->params.use_carrier) {
>> 		link_reporting = bond_check_dev_link(bond, slave_dev, 1);
>>@@ -2538,8 +2539,8 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_
>> {
>> 	struct sk_buff *skb;
>> 
>>-	pr_debug("arp %d on slave %s: dst %x src %x vid %d\n", arp_op,
>>-	       slave_dev->name, dest_ip, src_ip, vlan_id);
>>+	pr_debug("arp %d on slave %s: dst %x src %x vid %d j %lu\n", arp_op,
>>+		 slave_dev->name, dest_ip, src_ip, vlan_id, jiffies);
>> 	       
>> 	skb = arp_create(arp_op, ETH_P_ARP, dest_ip, slave_dev, src_ip,
>> 			 NULL, slave_dev->dev_addr, NULL);
>>@@ -2679,8 +2680,6 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
>> 
>> 	targets = bond->params.arp_targets;
>> 	for (i = 0; (i < BOND_MAX_ARP_TARGETS) && targets[i]; i++) {
>>-		pr_debug("bva: sip %pI4 tip %pI4 t[%d] %pI4 bhti(tip) %d\n",
>>-			&sip, &tip, i, &targets[i], bond_has_this_ip(bond, tip));
>> 		if (sip == targets[i]) {
>> 			if (bond_has_this_ip(bond, tip))
>> 				slave->last_arp_rx = jiffies;
>>@@ -2689,35 +2688,36 @@ 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 net_device *dev)
>> {
>> 	struct arphdr *arp;
>> 	struct slave *slave;
>>+	struct net_device *bond_dev = dev->master;
>> 	struct bonding *bond;
>> 	unsigned char *arp_ptr;
>> 	__be32 sip, tip;
>> 
>> 	if (dev_net(dev) != &init_net)
>>-		goto out;
>>+		return;
>> 
>>-	if (!(dev->priv_flags & IFF_BONDING) || !(dev->flags & IFF_MASTER))
>>-		goto out;
>>+	bond = netdev_priv(bond_dev);
>> 
>>-	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");
>>-
>>-	slave = bond_get_slave_by_dev(bond, orig_dev);
>>+	slave = bond_get_slave_by_dev(bond, dev);
>> 	if (!slave || !slave_do_arp_validate(bond, slave))
>> 		goto out_unlock;
>> 
>> 	if (!pskb_may_pull(skb, arp_hdr_len(dev)))
>> 		goto out_unlock;
>> 
>>-	arp = arp_hdr(skb);
>>+	/* Can't use arp_hdr; it's not initialized yet. */
>>+	arp = (struct arphdr *)skb->data;
>>+
>>+	pr_debug("arp: hln %d p_t %d hrd %x pro %x pln %d\n",
>>+	       arp->ar_hln, skb->pkt_type, ntohs(arp->ar_hrd),
>>+	       ntohs(arp->ar_pro), arp->ar_pln);
>>+
>> 	if (arp->ar_hln != dev->addr_len ||
>> 	    skb->pkt_type == PACKET_OTHERHOST ||
>> 	    skb->pkt_type == PACKET_LOOPBACK ||
>>@@ -2732,29 +2732,67 @@ static int bond_arp_rcv(struct sk_buff *skb, struct net_device *dev, struct pack
>> 	arp_ptr += 4 + dev->addr_len;
>> 	memcpy(&tip, arp_ptr, 4);
>> 
>>-	pr_debug("bond_arp_rcv: %s %s/%d av %d sv %d sip %pI4 tip %pI4\n",
>>-		bond->dev->name, slave->dev->name, slave->state,
>>-		bond->params.arp_validate, slave_do_arp_validate(bond, slave),
>>-		&sip, &tip);
>>-
>>-	/*
>>-	 * Backup slaves won't see the ARP reply, but do come through
>>-	 * here for each ARP probe (so we swap the sip/tip to validate
>>-	 * the probe).  In a "redundant switch, common router" type of
>>-	 * configuration, the ARP probe will (hopefully) travel from
>>-	 * the active, through one switch, the router, then the other
>>-	 * switch before reaching the backup.
>>-	 */
>>-	if (slave->state == BOND_STATE_ACTIVE)
>>+	switch (ntohs(arp->ar_op)) {
>>+	case ARPOP_REPLY:
>> 		bond_validate_arp(bond, slave, sip, tip);
>>-	else
>>+		break;
>>+	case ARPOP_REQUEST:
>> 		bond_validate_arp(bond, slave, tip, sip);
>>+		break;
>>+	}
>> 
>> out_unlock:
>> 	read_unlock(&bond->lock);
>>-out:
>>-	dev_kfree_skb(skb);
>>-	return NET_RX_SUCCESS;
>>+}
>>+
>>+/*
>>+ * Called by core packet processing in netif_receive_skb and in VLAN fast
>>+ * path to (a) determine if packet should be dropped, and (b) to perform
>>+ * ARP monitor processing (last_rx, validation).
>>+ *
>>+ * For the VLAN case, called before the skb->dev is reassigned to the
>>+ * VLAN.
>>+ *
>>+ * Returns 1 if frame should nominally be dropped; 0 if it should be kept.
>>+ *
>>+ * We want to keep:
>>+ * - all traffic on active slaves
>>+ * - some traffic on inactive slaves: non-broadcast and non-multicast in
>>+ * ALB/TLB mode and LACP frames in 802.3ad mode.
>>+ *
>>+ * ARP frames are handled as normal traffic; the ARP monitor handling
>>+ * takes place here, so they need not be kept on inactive slaves.
>>+ */
>>+static int bond_handle_frame(struct sk_buff *skb)
>>+{
>>+	struct net_device *dev;
>>+	struct net_device *master;
>>+
>>+	dev = skb->dev;
>>+	master = dev->master;
>>+	if (!master || !master->priv_flags & IFF_BONDING)
>>+		return 0;
>>+
>>+	if (master->priv_flags & IFF_MASTER_ARPMON) {
>>+		dev->last_rx = jiffies;
>>+		if ((dev->priv_flags & IFF_SLAVE_NEEDARP) &&
>>+		    skb->protocol == __constant_htons(ETH_P_ARP))
>>+			bond_handle_arp(skb, dev);
>>+	}
>>+
>>+	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)
>>+				return 0;
>>+		}
>>+		if (master->priv_flags & IFF_MASTER_8023AD &&
>>+		    skb->protocol == __constant_htons(ETH_P_SLOW))
>>+			return 0;
>>+
>>+		return 1;
>>+	}
>>+	return 0;
>> }
>> 
>> /*
>>@@ -3688,6 +3726,7 @@ static void bond_unregister_lacpdu(struct bonding *bond)
>> 
>> void bond_register_arp(struct bonding *bond)
>> {
>>+#if 0
>> 	struct packet_type *pt = &bond->arp_mon_pt;
>> 
>> 	if (pt->type)
>>@@ -3697,14 +3736,17 @@ void bond_register_arp(struct bonding *bond)
>> 	pt->dev = bond->dev;
>> 	pt->func = bond_arp_rcv;
>> 	dev_add_pack(pt);
>>+#endif
>> }
>> 
>> void bond_unregister_arp(struct bonding *bond)
>> {
>>+#if 0
>> 	struct packet_type *pt = &bond->arp_mon_pt;
>> 
>> 	dev_remove_pack(pt);
>> 	pt->type = 0;
>>+#endif
>> }
>> 
>> /*---------------------------- Hashing Policies -----------------------------*/
>>@@ -5188,6 +5230,8 @@ out_rtnl:
>> 	return res;
>> }
>> 
>>+extern int (*bond_handle_frame_hook)(struct sk_buff *skb);
>>+
>> static int __init bonding_init(void)
>> {
>> 	int i;
>>@@ -5221,6 +5265,8 @@ static int __init bonding_init(void)
>> 	register_inetaddr_notifier(&bond_inetaddr_notifier);
>> 	bond_register_ipv6_notifier();
>> 
>>+	bond_handle_frame_hook = bond_handle_frame;
>>+
>> 	goto out;
>> err:
>> 	list_for_each_entry(bond, &bond_dev_list, bond_list) {
>>@@ -5249,6 +5295,9 @@ static void __exit bonding_exit(void)
>> 	rtnl_lock();
>> 	bond_free_all();
>> 	rtnl_unlock();
>>+
>>+	bond_handle_frame_hook = NULL;
>>+
>> }
>> 
>> module_init(bonding_init);
>>diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
>>index 18cf478..0e9f0e9 100644
>>--- a/drivers/net/bonding/bond_sysfs.c
>>+++ b/drivers/net/bonding/bond_sysfs.c
>>@@ -484,8 +484,9 @@ static ssize_t bonding_store_arp_validate(struct device *d,
>> 					  struct device_attribute *attr,
>> 					  const char *buf, size_t count)
>> {
>>-	int new_value;
>>+	int new_value, i;
>> 	struct bonding *bond = to_bond(d);
>>+	struct slave *slave;
>> 
>> 	new_value = bond_parse_parm(buf, arp_validate_tbl);
>> 	if (new_value < 0) {
>>@@ -504,13 +505,12 @@ static ssize_t bonding_store_arp_validate(struct device *d,
>> 	       bond->dev->name, arp_validate_tbl[new_value].modename,
>> 	       new_value);
>> 
>>-	if (!bond->params.arp_validate && new_value) {
>>-		bond_register_arp(bond);
>>-	} else if (bond->params.arp_validate && !new_value) {
>>-		bond_unregister_arp(bond);
>>-	}
>>+	if (bond->params.arp_validate != new_value) {
>>+		bond->params.arp_validate = new_value;
>> 
>>-	bond->params.arp_validate = new_value;
>>+		bond_for_each_slave(bond, slave, i)
>>+			bond_fix_slave_validate_flag(bond, slave);
>>+	}
>> 
>> 	return count;
>> }
>>diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
>>index ca849d2..275f08d 100644
>>--- a/drivers/net/bonding/bonding.h
>>+++ b/drivers/net/bonding/bonding.h
>>@@ -283,6 +283,15 @@ static inline unsigned long slave_last_rx(struct bonding *bond,
>> 	return slave->dev->last_rx;
>> }
>> 
>>+static inline void bond_fix_slave_validate_flag(struct bonding *bond,
>>+					       struct slave *slave)
>>+{
>>+	if (slave_do_arp_validate(bond, slave))
>>+		slave->dev->priv_flags |= IFF_SLAVE_NEEDARP;
>>+	else
>>+		slave->dev->priv_flags &= ~IFF_SLAVE_NEEDARP;
>>+}
>>+
>> static inline void bond_set_slave_inactive_flags(struct slave *slave)
>> {
>> 	struct bonding *bond = netdev_priv(slave->dev->master);
>>@@ -290,14 +299,16 @@ static inline void bond_set_slave_inactive_flags(struct slave *slave)
>> 	    bond->params.mode != BOND_MODE_ALB)
>> 		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;
>>+	bond_fix_slave_validate_flag(bond, slave);
>> }
>> 
>> static inline void bond_set_slave_active_flags(struct slave *slave)
>> {
>>+	struct bonding *bond = netdev_priv(slave->dev->master);
>>+
>> 	slave->state = BOND_STATE_ACTIVE;
>>-	slave->dev->priv_flags &= ~(IFF_SLAVE_INACTIVE | IFF_SLAVE_NEEDARP);
>>+	slave->dev->priv_flags &= ~IFF_SLAVE_INACTIVE;
>>+	bond_fix_slave_validate_flag(bond, slave);
>> }
>> 
>> static inline void bond_set_master_3ad_flags(struct bonding *bond)
>>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>>index 2e7783f..3dafd8f 100644
>>--- a/include/linux/netdevice.h
>>+++ b/include/linux/netdevice.h
>>@@ -1874,6 +1874,7 @@ static inline void netif_set_gso_max_size(struct net_device *dev,
>> 	dev->gso_max_size = size;
>> }
>> 
>>+#if 0
>> /* 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.
>>@@ -1906,6 +1907,8 @@ static inline int skb_bond_should_drop(struct sk_buff *skb)
>> 	}
>> 	return 0;
>> }
>>+#endif
>>+extern int skb_bond_should_drop(struct sk_buff *skb);
>> 
>> extern struct pernet_operations __net_initdata loopback_net_ops;
>> #endif /* __KERNEL__ */
>>diff --git a/net/core/dev.c b/net/core/dev.c
>>index 91d792d..ac5a37e 100644
>>--- a/net/core/dev.c
>>+++ b/net/core/dev.c
>>@@ -2098,6 +2098,56 @@ static inline struct sk_buff *handle_macvlan(struct sk_buff *skb,
>> #define handle_macvlan(skb, pt_prev, ret, orig_dev)	(skb)
>> #endif
>> 
>>+#if defined(CONFIG_BONDING) || defined(CONFIG_BONDING_MODULE)
>>+int (*bond_handle_frame_hook)(struct sk_buff *skb);
>>+EXPORT_SYMBOL_GPL(bond_handle_frame_hook);
>>+
>>+/* 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.
>>+ */
>>+int skb_bond_should_drop(struct sk_buff *skb)
>>+{
>>+	struct net_device *dev = skb->dev;
>>+	struct net_device *master = dev->master;
>>+
>>+	if (master)
>>+		return bond_handle_frame_hook(skb);
>
>Maybe this hook can be called from netif_receive_skb() directly. You would safe
>at least 2 dereferences, 1 if check. You would also need to add
>"skb->dev->master &&" to if in __vlan_hwaccel_rx() and vlan_gro_common().

	This won't work, because the VLAN code reassigns skb->dev to the
VLAN device before calling netif_receive_skb.

	In the VLAN path, the second call to skb_bond_should_drop (the
first is within the VLAN code itself, __vlan_hwaccel_rx or
vlan_gro_common, the second is netif_receive_skb) won't call the hook,
because the VLAN device has no dev->master.

	This is the whole reason for the hook: to process the ARP before
VLAN reassigns skb->dev.  Once that happens, the actual device the ARP
arrived on is lost.

	-J


>>+
>>+	return 0;
>>+
>>+#if 0
>>+		if (master->priv_flags & IFF_MASTER_ARPMON)
>>+			dev->last_rx = jiffies;
>>+
>>+		if (dev->priv_flags & IFF_SLAVE_INACTIVE) {
>>+			if ((dev->priv_flags & IFF_SLAVE_NEEDARP) &&
>>+			    skb->protocol == __constant_htons(ETH_P_ARP))
>>+				return 0;
>>+
>>+			if (master->priv_flags & IFF_MASTER_ALB) {
>>+				if (skb->pkt_type != PACKET_BROADCAST &&
>>+				    skb->pkt_type != PACKET_MULTICAST)
>>+					return 0;
>>+			}
>>+			if (master->priv_flags & IFF_MASTER_8023AD &&
>>+			    skb->protocol == __constant_htons(ETH_P_SLOW))
>>+				return 0;
>>+
>>+			return 1;
>>+		}
>>+	}
>>+	return 0;
>>+#endif /* 0 */
>>+}
>>+#else
>>+int skb_bond_should_drop(struct sk_buff *skb)
>>+{
>>+	return 0;
>>+}
>>+#endif
>>+EXPORT_SYMBOL_GPL(skb_bond_should_drop);
>>+
>> #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
>>
>>
>>---
>>	-Jay Vosburgh, IBM Linux Technology Center, fubar@...ibm.com
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