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>
This commit is contained in:
Fischer, Anna 2009-08-13 06:55:16 +00:00 committed by David S. Miller
parent 8dd07086a1
commit 3982d3d28b
4 changed files with 23 additions and 1 deletions

View File

@ -22,7 +22,8 @@
static inline int should_deliver(const struct net_bridge_port *p,
const struct sk_buff *skb)
{
return (skb->dev != p->dev && p->state == BR_STATE_FORWARDING);
return (((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
p->state == BR_STATE_FORWARDING);
}
static inline unsigned packet_length(const struct sk_buff *skb)

View File

@ -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);

View File

@ -81,6 +81,9 @@ struct net_bridge_port
struct timer_list message_age_timer;
struct kobject kobj;
struct rcu_head rcu;
unsigned long flags;
#define BR_HAIRPIN_MODE 0x00000001
};
struct net_bridge

View File

@ -143,6 +143,22 @@ static ssize_t store_flush(struct net_bridge_port *p, unsigned long v)
}
static BRPORT_ATTR(flush, S_IWUSR, NULL, store_flush);
static ssize_t show_hairpin_mode(struct net_bridge_port *p, char *buf)
{
int hairpin_mode = (p->flags & BR_HAIRPIN_MODE) ? 1 : 0;
return sprintf(buf, "%d\n", hairpin_mode);
}
static ssize_t store_hairpin_mode(struct net_bridge_port *p, unsigned long v)
{
if (v)
p->flags |= BR_HAIRPIN_MODE;
else
p->flags &= ~BR_HAIRPIN_MODE;
return 0;
}
static BRPORT_ATTR(hairpin_mode, S_IRUGO | S_IWUSR,
show_hairpin_mode, store_hairpin_mode);
static struct brport_attribute *brport_attrs[] = {
&brport_attr_path_cost,
&brport_attr_priority,
@ -159,6 +175,7 @@ static struct brport_attribute *brport_attrs[] = {
&brport_attr_forward_delay_timer,
&brport_attr_hold_timer,
&brport_attr_flush,
&brport_attr_hairpin_mode,
NULL
};