net/bridge: Add 'hairpin' port forwarding mode

This patch adds a 'hairpin' (also called 'reflective relay') mode
port configuration to the Linux Ethernet bridge kernel module.
A bridge supporting hairpin forwarding mode can send frames back
out through the port the frame was received on.

Hairpin mode is required to support basic VEPA (Virtual
Ethernet Port Aggregator) capabilities.

You can find additional information on VEPA here:
http://tech.groups.yahoo.com/group/evb/
http://www.ieee802.org/1/files/public/docs2009/new-hudson-vepa_seminar-20090514d.pdf
http://www.internet2.edu/presentations/jt2009jul/20090719-congdon.pdf

An additional patch 'bridge-utils: Add 'hairpin' port forwarding mode'
is provided to allow configuring hairpin mode from userspace tools.

Signed-off-by: Paul Congdon <paul.congdon@hp.com>
Signed-off-by: Anna Fischer <anna.fischer@hp.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index eb404dc3ed6e..e486f1fc3632 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -256,6 +256,7 @@ static struct net_bridge_port *new_nbp(struct net_bridge *br,
         p->path_cost = port_cost(dev);
         p->priority = 0x8000 >> BR_PORT_BITS;
         p->port_no = index;
+        p->flags = 0;
         br_init_port(p);
         p->state = BR_STATE_DISABLED;
         br_stp_port_timer_init(p);