net: introduce ethernet teaming device

This patch introduces new network device called team. It supposes to be
very fast, simple, userspace-driven alternative to existing bonding
driver.

Userspace library called libteam with couple of demo apps is available
here:
https://github.com/jpirko/libteam
Note it's still in its dipers atm.

team<->libteam use generic netlink for communication. That and rtnl
suppose to be the only way to configure team device, no sysfs etc.

Python binding of libteam was recently introduced.
Daemon providing arpmon/miimon active-backup functionality will be
introduced shortly. All what's necessary is already implemented in
kernel team driver.

v7->v8:
	- check ndo_ndo_vlan_rx_[add/kill]_vid functions before calling
	  them.
	- use dev_kfree_skb_any() instead of dev_kfree_skb()

v6->v7:
	- transmit and receive functions are not checked in hot paths.
	  That also resolves memory leak on transmit when no port is
	  present

v5->v6:
	- changed couple of _rcu calls to non _rcu ones in non-readers

v4->v5:
	- team_change_mtu() uses team->lock while travesing though port
	  list
	- mac address changes are moved completely to jurisdiction of
	  userspace daemon. This way the daemon can do FOM1, FOM2 and
	  possibly other weird things with mac addresses.
	  Only round-robin mode sets up all ports to bond's address then
	  enslaved.
	- Extended Kconfig text

v3->v4:
	- remove redundant synchronize_rcu from __team_change_mode()
	- revert "set and clear of mode_ops happens per pointer, not per
	  byte"
	- extend comment of function __team_change_mode()

v2->v3:
	- team_change_mtu() uses rcu version of list traversal to unwind
	- set and clear of mode_ops happens per pointer, not per byte
	- port hashlist changed to be embedded into team structure
	- error branch in team_port_enter() does cleanup now
	- fixed rtln->rtnl

v1->v2:
	- modes are made as modules. Makes team more modular and
	  extendable.
	- several commenters' nitpicks found on v1 were fixed
	- several other bugs were fixed.
	- note I ignored Eric's comment about roundrobin port selector
	  as Eric's way may be easily implemented as another mode (mode
	  "random") in future.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 137 insertions, 0 deletions

diff --git a/drivers/net/team/team_mode_activebackup.c b/drivers/net/team/team_mode_activebackup.c
new file mode 100644
index 00000000000..6fe920c440b
--- /dev/null
+++ b/drivers/net/team/team_mode_activebackup.c
@@ -0,0 +1,137 @@
+/*
+ * net/drivers/team/team_mode_activebackup.c - Active-backup mode for team
+ * Copyright (c) 2011 Jiri Pirko <jpirko@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <net/rtnetlink.h>
+#include <linux/if_team.h>
+
+struct ab_priv {
+	struct team_port __rcu *active_port;
+};
+
+static struct ab_priv *ab_priv(struct team *team)
+{
+	return (struct ab_priv *) &team->mode_priv;
+}
+
+static rx_handler_result_t ab_receive(struct team *team, struct team_port *port,
+				      struct sk_buff *skb) {
+	struct team_port *active_port;
+
+	active_port = rcu_dereference(ab_priv(team)->active_port);
+	if (active_port != port)
+		return RX_HANDLER_EXACT;
+	return RX_HANDLER_ANOTHER;
+}
+
+static bool ab_transmit(struct team *team, struct sk_buff *skb)
+{
+	struct team_port *active_port;
+
+	active_port = rcu_dereference(ab_priv(team)->active_port);
+	if (unlikely(!active_port))
+		goto drop;
+	skb->dev = active_port->dev;
+	if (dev_queue_xmit(skb))
+		return false;
+	return true;
+
+drop:
+	dev_kfree_skb_any(skb);
+	return false;
+}
+
+static void ab_port_leave(struct team *team, struct team_port *port)
+{
+	if (ab_priv(team)->active_port == port)
+		rcu_assign_pointer(ab_priv(team)->active_port, NULL);
+}
+
+static int ab_active_port_get(struct team *team, void *arg)
+{
+	u32 *ifindex = arg;
+
+	*ifindex = 0;
+	if (ab_priv(team)->active_port)
+		*ifindex = ab_priv(team)->active_port->dev->ifindex;
+	return 0;
+}
+
+static int ab_active_port_set(struct team *team, void *arg)
+{
+	u32 *ifindex = arg;
+	struct team_port *port;
+
+	list_for_each_entry_rcu(port, &team->port_list, list) {
+		if (port->dev->ifindex == *ifindex) {
+			rcu_assign_pointer(ab_priv(team)->active_port, port);
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+static struct team_option ab_options[] = {
+	{
+		.name = "activeport",
+		.type = TEAM_OPTION_TYPE_U32,
+		.getter = ab_active_port_get,
+		.setter = ab_active_port_set,
+	},
+};
+
+int ab_init(struct team *team)
+{
+	team_options_register(team, ab_options, ARRAY_SIZE(ab_options));
+	return 0;
+}
+
+void ab_exit(struct team *team)
+{
+	team_options_unregister(team, ab_options, ARRAY_SIZE(ab_options));
+}
+
+static const struct team_mode_ops ab_mode_ops = {
+	.init			= ab_init,
+	.exit			= ab_exit,
+	.receive		= ab_receive,
+	.transmit		= ab_transmit,
+	.port_leave		= ab_port_leave,
+};
+
+static struct team_mode ab_mode = {
+	.kind		= "activebackup",
+	.owner		= THIS_MODULE,
+	.priv_size	= sizeof(struct ab_priv),
+	.ops		= &ab_mode_ops,
+};
+
+static int __init ab_init_module(void)
+{
+	return team_mode_register(&ab_mode);
+}
+
+static void __exit ab_cleanup_module(void)
+{
+	team_mode_unregister(&ab_mode);
+}
+
+module_init(ab_init_module);
+module_exit(ab_cleanup_module);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jiri Pirko <jpirko@redhat.com>");
+MODULE_DESCRIPTION("Active-backup mode for team");
+MODULE_ALIAS("team-mode-activebackup");