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Message-ID: <20140430101842.GA22962@redhat.com>
Date: Wed, 30 Apr 2014 13:18:42 +0300
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Vlad Yasevich <vyasevic@...hat.com>
Cc: netdev@...r.kernel.org, bridge@...ts.linux-foundation.org,
shemminger@...tta.com, jhs@...atatu.com, john.r.fastabend@...el.com
Subject: Re: [RFC PATCH v2 net-next 2/7] bridge: Keep track of ports capable
of automatic discovery.
On Tue, Apr 29, 2014 at 05:20:23PM -0400, Vlad Yasevich wrote:
> By default, ports on the bridge are capable of automatic
> discovery of nodes located behind the port. This is accomplished
> via flooding of unknown traffic (BR_FLOOD) and learning the
> mac addresses from these packets (BR_LEARNING).
> If the above functionality is diabled by turning off these
> flags, the port requires static configuration in the form
> of static FDB entries to function properly.
>
> This patch adds functionality to keep track of all ports
> capable of automatic discovery. This will later be used
> to control promiscuity settings.
>
> Signed-off-by: Vlad Yasevich <vyasevic@...hat.com>
> ---
> net/bridge/br_if.c | 27 +++++++++++++++++++++++++++
> net/bridge/br_netlink.c | 3 +++
> net/bridge/br_private.h | 6 ++++++
> net/bridge/br_sysfs_if.c | 6 +++++-
> 4 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
> index 5262b86..7e60c4c 100644
> --- a/net/bridge/br_if.c
> +++ b/net/bridge/br_if.c
> @@ -85,6 +85,18 @@ void br_port_carrier_check(struct net_bridge_port *p)
> spin_unlock_bh(&br->lock);
> }
>
> +static void nbp_update_port_count(struct net_bridge *br)
> +{
> + struct net_bridge_port *p;
> + u32 cnt = 0;
> +
> + list_for_each_entry(p, &br->port_list, list) {
> + if (br_is_auto_port(p))
> + cnt++;
> + }
> + br->auto_cnt = cnt;
> +}
> +
> static void release_nbp(struct kobject *kobj)
> {
> struct net_bridge_port *p
> @@ -146,6 +158,8 @@ static void del_nbp(struct net_bridge_port *p)
>
> list_del_rcu(&p->list);
>
> + nbp_update_port_count(br);
> +
> dev->priv_flags &= ~IFF_BRIDGE_PORT;
>
> netdev_rx_handler_unregister(dev);
> @@ -384,6 +398,8 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
>
> list_add_rcu(&p->list, &br->port_list);
>
> + nbp_update_port_count(br);
> +
> netdev_update_features(br->dev);
>
> if (br->dev->needed_headroom < dev->needed_headroom)
> @@ -455,3 +471,14 @@ int br_del_if(struct net_bridge *br, struct net_device *dev)
>
> return 0;
> }
> +
> +void br_port_flags_change(struct net_bridge_port *p, unsigned long old_flags)
> +{
> + struct net_bridge *br = p->br;
> + unsigned long mask = old_flags ^ p->flags;
> +
> + if (!(mask & BR_AUTO_MASK))
> + return;
> +
> + nbp_update_port_count(br);
> +}
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index e74b6d53..01382b9 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -328,6 +328,7 @@ static void br_set_port_flag(struct net_bridge_port *p, struct nlattr *tb[],
> static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
> {
> int err;
> + unsigned long old_flags = p->flags;
>
> br_set_port_flag(p, tb, IFLA_BRPORT_MODE, BR_HAIRPIN_MODE);
> br_set_port_flag(p, tb, IFLA_BRPORT_GUARD, BR_BPDU_GUARD);
> @@ -353,6 +354,8 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
> if (err)
> return err;
> }
> +
> + br_port_flags_change(p, old_flags ^ p->flags);
> return 0;
> }
>
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 06811d7..db714a1 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -174,6 +174,7 @@ struct net_bridge_port
> #define BR_ADMIN_COST 0x00000010
> #define BR_LEARNING 0x00000020
> #define BR_FLOOD 0x00000040
> +#define BR_AUTO_MASK (BR_FLOOD | BR_LEARNING)
>
> #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
> struct bridge_mcast_query ip4_query;
> @@ -198,6 +199,8 @@ struct net_bridge_port
> #endif
> };
>
> +#define br_is_auto_port(p) (((p)->flags & BR_AUTO_MASK) == BR_AUTO_MASK)
> +
I think you
really want ((p)->flags & BR_AUTO_MASK) instead without
== BR_AUTO_MASK.
For example if learning is off but flood is on, things work
(slowly) automatically without configuring static entries.
OTOH if flood is off but learning is on, a bunch of packets
might get dropped but eventually you might learn the
mac and then networking will start working.
> #define br_port_exists(dev) (dev->priv_flags & IFF_BRIDGE_PORT)
>
> static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *dev)
> @@ -290,6 +293,7 @@ struct net_bridge
> struct timer_list topology_change_timer;
> struct timer_list gc_timer;
> struct kobject *ifobj;
> + u32 auto_cnt;
> #ifdef CONFIG_BRIDGE_VLAN_FILTERING
> u8 vlan_enabled;
> struct net_port_vlans __rcu *vlan_info;
> @@ -415,6 +419,8 @@ int br_del_if(struct net_bridge *br, struct net_device *dev);
> int br_min_mtu(const struct net_bridge *br);
> netdev_features_t br_features_recompute(struct net_bridge *br,
> netdev_features_t features);
> +void br_port_flags_change(struct net_bridge_port *port,
> + unsigned long old_flags);
>
> /* br_input.c */
> int br_handle_frame_finish(struct sk_buff *skb);
> diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
> index 112a25e..58c26e3 100644
> --- a/net/bridge/br_sysfs_if.c
> +++ b/net/bridge/br_sysfs_if.c
> @@ -49,7 +49,10 @@ static BRPORT_ATTR(_name, S_IRUGO | S_IWUSR, \
> static int store_flag(struct net_bridge_port *p, unsigned long v,
> unsigned long mask)
> {
> - unsigned long flags = p->flags;
> + unsigned long flags;
> + unsigned long old_flags;
> +
> + old_flags = flags = p->flags;
>
> if (v)
> flags |= mask;
> @@ -58,6 +61,7 @@ static int store_flag(struct net_bridge_port *p, unsigned long v,
>
> if (flags != p->flags) {
> p->flags = flags;
> + br_port_flags_change(p, old_flags ^ flags);
> br_ifinfo_notify(RTM_NEWLINK, p);
> }
> return 0;
> --
> 1.9.0
--
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