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>

Documentation/networking/team.txt

@@ -0,0 +1,2 @@
+Team devices are driven from userspace via libteam library which is here:
+	https://github.com/jpirko/libteam

MAINTAINERS

@@ -6484,6 +6484,13 @@ W:	http://tcp-lp-mod.sourceforge.net/
 S:	Maintained
 F:	net/ipv4/tcp_lp.c
 
+TEAM DRIVER
+M:	Jiri Pirko <jpirko@redhat.com>
+L:	netdev@vger.kernel.org
+S:	Supported
+F:	drivers/net/team/
+F:	include/linux/if_team.h
+
 TEGRA SUPPORT
 M:	Colin Cross <ccross@android.com>
 M:	Olof Johansson <olof@lixom.net>

drivers/net/Kconfig

@@ -125,6 +125,8 @@ config IFB
 	  'ifb1' etc.
 	  Look at the iproute2 documentation directory for usage etc
 
+source "drivers/net/team/Kconfig"
+
 config MACVLAN
 	tristate "MAC-VLAN support (EXPERIMENTAL)"
 	depends on EXPERIMENTAL

drivers/net/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_NET) += Space.o loopback.o
 obj-$(CONFIG_NETCONSOLE) += netconsole.o
 obj-$(CONFIG_PHYLIB) += phy/
 obj-$(CONFIG_RIONET) += rionet.o
+obj-$(CONFIG_NET_TEAM) += team/
 obj-$(CONFIG_TUN) += tun.o
 obj-$(CONFIG_VETH) += veth.o
 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o

drivers/net/team/Kconfig

@@ -0,0 +1,43 @@
+menuconfig NET_TEAM
+	tristate "Ethernet team driver support (EXPERIMENTAL)"
+	depends on EXPERIMENTAL
+	---help---
+	  This allows one to create virtual interfaces that teams together
+	  multiple ethernet devices.
+
+	  Team devices can be added using the "ip" command from the
+	  iproute2 package:
+
+	  "ip link add link [ address MAC ] [ NAME ] type team"
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called team.
+
+if NET_TEAM
+
+config NET_TEAM_MODE_ROUNDROBIN
+	tristate "Round-robin mode support"
+	depends on NET_TEAM
+	---help---
+	  Basic mode where port used for transmitting packets is selected in
+	  round-robin fashion using packet counter.
+
+	  All added ports are setup to have bond's mac address.
+
+	  To compile this team mode as a module, choose M here: the module
+	  will be called team_mode_roundrobin.
+
+config NET_TEAM_MODE_ACTIVEBACKUP
+	tristate "Active-backup mode support"
+	depends on NET_TEAM
+	---help---
+	  Only one port is active at a time and the rest of ports are used
+	  for backup.
+
+	  Mac addresses of ports are not modified. Userspace is responsible
+	  to do so.
+
+	  To compile this team mode as a module, choose M here: the module
+	  will be called team_mode_activebackup.
+
+endif # NET_TEAM

drivers/net/team/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the network team driver
+#
+
+obj-$(CONFIG_NET_TEAM) += team.o
+obj-$(CONFIG_NET_TEAM_MODE_ROUNDROBIN) += team_mode_roundrobin.o
+obj-$(CONFIG_NET_TEAM_MODE_ACTIVEBACKUP) += team_mode_activebackup.o