[PATCH] Add support for HW accel. slaves

Now that David Miller accepted the first half of this set into 2.6,
I'm resending the last half to you for inclusion in netdev-2.6.

Tested against latest netdev-2.6. Summary:

Change the bond interface to publish full VLAN hardware acceleration
offloading capabilities, and add capability in all xmit functions to
take special care for VLAN HW accel. tagged skb's that are going out
through a slave that is not offloading capable.

Add a mechanism to collect and save the VLAN Id's that have been
added on top of a bond interface, and propagate the register/add/kill
operations to the slaves.

Add blocking mechanism to prevent adding VLAN interfaces on top of a
bond that contains VLAN challenged slaves and to prevent adding VLAN
challenged slaves to a bond that already has VLAN interfaces on top
of it.

Add a section about VLAN to Documentation/networking/bonding.txt and
also correct some minor spelling/grammer errors.

Documentation/networking/bonding.txt

@@ -31,6 +31,7 @@ Verifying Bond Configuration
 Frequently Asked Questions
 High Availability
 Promiscuous Sniffing notes
+8021q VLAN support
 Limitations
 Resources and Links
 
@@ -140,10 +141,6 @@ probeall bond0 eth0 eth1 bonding
 Be careful not to reference bond0 itself at the end of the line, or modprobe
 will die in an endless recursive loop.
 
-To have device characteristics (such as MTU size) propagate to slave devices,
-set the bond characteristics before enslaving the device.  The characteristics
-are propagated during the enslave process.
-
 If running SNMP agents, the bonding driver should be loaded before any network
 drivers participating in a bond. This requirement is due to the the interface
 index (ipAdEntIfIndex) being associated to the first interface found with a
@@ -601,7 +598,7 @@ Frequently Asked Questions
 	For ethernet cards not supporting MII status, the arp_interval and
         arp_ip_target parameters must be specified for bonding to work
         correctly. If packets have not been sent or received during the
-        specified arp_interval durration, an ARP request is sent to the
+        specified arp_interval duration, an ARP request is sent to the
         targets to generate send and receive traffic. If after this
         interval, either the successful send and/or receive count has not
         incremented, the next slave in the sequence will become the active
@@ -669,16 +666,8 @@ Frequently Asked Questions
 	that will be added.
 
 	To restore your slaves' MAC addresses, you need to detach them
-	from the bond (`ifenslave -d bond0 eth0'), set them down
-	(`ifconfig eth0 down'), unload the drivers (`rmmod 3c59x', for
-	example) and reload them to get the MAC addresses from their
-	eeproms. If the driver is shared by several devices, you need
-	to turn them all down. Another solution is to look for the MAC
-	address at boot time (dmesg or tail /var/log/messages) and to
-	reset it by hand with ifconfig :
-
-	  # ifconfig eth0 down
-	  # ifconfig eth0 hw ether 00:20:40:60:80:A0
+	from the bond (`ifenslave -d bond0 eth0'). The bonding driver will then
+	restore the MAC addresses that the slaves had before they were enslaved.
 
 9.  Which transmit polices can be used?
 
@@ -843,7 +832,7 @@ point of failure" solution.
 
 In this configuration, there is an ISL - Inter Switch Link (could be a trunk),
 several servers (host1, host2 ...) attached to both switches each, and one or
-more ports to the outside world (port3...). One an only one slave on each host
+more ports to the outside world (port3...). One and only one slave on each host
 is active at a time, while all links are still monitored (the system can
 detect a failure of active and backup links).
 
@@ -933,6 +922,41 @@ capacity aggregating; but it works fine for unnumbered interfaces;
 just ignore all the warnings it emits.
 
 
+8021q VLAN support
+==================
+
+It is possible to configure VLAN devices over a bond interface using the 8021q
+driver. However, only packets coming from the 8021q driver and passing through
+bonding will be tagged by default. Self generated packets, like bonding's
+learning packets or ARP packets generated by either ALB mode or the ARP
+monitor mechanism, are tagged internally by bonding itself. As a result,
+bonding has to "learn" what VLAN IDs are configured on top of it, and it uses
+those IDs to tag self generated packets.
+
+For simplicity reasons, and to support the use of adapters that can do VLAN
+hardware acceleration offloding, the bonding interface declares itself as
+fully hardware offloaing capable, it gets the add_vid/kill_vid notifications
+to gather the necessary information, and it propagates those actions to the
+slaves.
+In case of mixed adapter types, hardware accelerated tagged packets that should
+go through an adapter that is not offloading capable are "un-accelerated" by the
+bonding driver so the VLAN tag sits in the regular location.
+
+VLAN interfaces *must* be added on top of a bonding interface only after
+enslaving at least one slave. This is because until the first slave is added the
+bonding interface has a HW address of 00:00:00:00:00:00, which will be copied by
+the VLAN interface when it is created.
+
+Notice that a problem would occur if all slaves are released from a bond that
+still has VLAN interfaces on top of it. When later coming to add new slaves, the
+bonding interface would get a HW address from the first slave, which might not
+match that of the VLAN interfaces. It is recommended that either all VLANs are
+removed and then re-added, or to manually set the bonding interface's HW
+address so it matches the VLAN's. (Note: changing a VLAN interface's HW address
+would set the underlying device -- i.e. the bonding interface -- to promiscouos
+mode, which might not be what you want).
+
+
 Limitations
 ===========
 The main limitations are :

drivers/net/bonding/bond_3ad.c

@@ -2362,6 +2362,7 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 	int agg_id;
 	int i;
 	struct ad_info ad_info;
+	int res = 1;
 
 	/* make sure that the slaves list will
 	 * not change during tx
@@ -2369,12 +2370,12 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 	read_lock(&bond->lock);
 
 	if (!BOND_IS_OK(bond)) {
-		goto free_out;
+		goto out;
 	}
 
 	if (bond_3ad_get_active_agg_info(bond, &ad_info)) {
 		printk(KERN_DEBUG "ERROR: bond_3ad_get_active_agg_info failed\n");
-		goto free_out;
+		goto out;
 	}
 
 	slaves_in_agg = ad_info.ports;
@@ -2383,7 +2384,7 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 	if (slaves_in_agg == 0) {
 		/*the aggregator is empty*/
 		printk(KERN_DEBUG "ERROR: active aggregator is empty\n");
-		goto free_out;
+		goto out;
 	}
 
 	slave_agg_no = (data->h_dest[5]^bond->dev->dev_addr[5]) % slaves_in_agg;
@@ -2401,7 +2402,7 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 
 	if (slave_agg_no >= 0) {
 		printk(KERN_ERR DRV_NAME ": Error: Couldn't find a slave to tx on for aggregator ID %d\n", agg_id);
-		goto free_out;
+		goto out;
 	}
 
 	start_at = slave;
@@ -2414,24 +2415,19 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 			slave_agg_id = agg->aggregator_identifier;
 		}
 
-		if (SLAVE_IS_OK(slave) && 
-		    agg && (slave_agg_id == agg_id)) {
-			skb->dev = slave->dev;			
-			skb->priority = 1;
-			dev_queue_xmit(skb);
-
-			goto out;
+		if (SLAVE_IS_OK(slave) && agg && (slave_agg_id == agg_id)) {
+			res = bond_dev_queue_xmit(bond, skb, slave->dev);
+			break;
 		}
 	}
 
 out:
+	if (res) {
+		/* no suitable interface, frame not sent */
+		dev_kfree_skb(skb);
+	}
 	read_unlock(&bond->lock);
 	return 0;
-
-free_out:
-	/* no suitable interface, frame not sent */
-	dev_kfree_skb(skb);
-	goto out;
 }
 
 int bond_3ad_lacpdu_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type* ptype)

drivers/net/bonding/bond_alb.c

@@ -1193,6 +1193,7 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 	int do_tx_balance = 1;
 	u32 hash_index = 0;
 	u8 *hash_start = NULL;
+	int res = 1;
 
 	/* make sure that the curr_active_slave and the slaves list do
 	 * not change during tx
@@ -1201,7 +1202,7 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 	read_lock(&bond->curr_slave_lock);
 
 	if (!BOND_IS_OK(bond)) {
-		goto free_out;
+		goto out;
 	}
 
 	switch (ntohs(skb->protocol)) {
@@ -1266,29 +1267,27 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 	}
 
 	if (tx_slave && SLAVE_IS_OK(tx_slave)) {
-		skb->dev = tx_slave->dev;
 		if (tx_slave != bond->curr_active_slave) {
 			memcpy(eth_data->h_source,
 			       tx_slave->dev->dev_addr,
 			       ETH_ALEN);
 		}
-		dev_queue_xmit(skb);
+
+		res = bond_dev_queue_xmit(bond, skb, tx_slave->dev);
 	} else {
-		/* no suitable interface, frame not sent */
 		if (tx_slave) {
 			tlb_clear_slave(bond, tx_slave, 0);
 		}
-		goto free_out;
 	}
 
 out:
+	if (res) {
+		/* no suitable interface, frame not sent */
+		dev_kfree_skb(skb);
+	}
 	read_unlock(&bond->curr_slave_lock);
 	read_unlock(&bond->lock);
 	return 0;
-
-free_out:
-	dev_kfree_skb(skb);
-	goto out;
 }
 
 void bond_alb_monitor(struct bonding *bond)

drivers/net/bonding/bonding.h

@@ -147,6 +147,11 @@ struct bond_params {
 	u32 arp_targets[BOND_MAX_ARP_TARGETS];
 };
 
+struct vlan_entry {
+	struct list_head vlan_list;
+	unsigned short vlan_id;
+};
+
 struct slave {
 	struct net_device *dev; /* first - usefull for panic debug */
 	struct slave *next;
@@ -196,6 +201,8 @@ struct bonding {
 	struct   ad_bond_info ad_info;
 	struct   alb_bond_info alb_info;
 	struct   bond_params params;
+	struct   list_head vlan_list;
+	struct   vlan_group *vlgrp;
 };
 
 /**
@@ -238,5 +245,7 @@ extern inline void bond_set_slave_active_flags(struct slave *slave)
 	slave->dev->flags &= ~IFF_NOARP;
 }
 
+int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev);
+
 #endif /* _LINUX_BONDING_H */