From 3982d3d28b02bed5312015762fe2112ccbaf9051 Mon Sep 17 00:00:00 2001 From: "Fischer, Anna" Date: Thu, 13 Aug 2009 06:55:16 +0000 Subject: [PATCH] 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 Signed-off-by: Anna Fischer Acked-by: Arnd Bergmann Signed-off-by: David S. Miller --- net/bridge/br_forward.c | 3 ++- net/bridge/br_if.c | 1 + net/bridge/br_private.h | 3 +++ net/bridge/br_sysfs_if.c | 17 +++++++++++++++++ 4 files changed, 23 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c index d2c27c808d3..bc1704ac6cd 100644 --- a/net/bridge/br_forward.c +++ b/net/bridge/br_forward.c @@ -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) diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index eb404dc3ed6..e486f1fc363 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); diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index d5b5537272b..8319247dad5 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -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 diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c index 4a3cdf8f381..820643a3ba9 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -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 };