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Message-ID: <20121218230407.GB1135@redhat.com>
Date: Wed, 19 Dec 2012 01:04:07 +0200
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Vlad Yasevich <vyasevic@...hat.com>
Cc: netdev@...r.kernel.org, shemminger@...tta.com, davem@...emloft.net,
or.gerlitz@...il.com, jhs@...atatu.com
Subject: Re: [PATCH V2 09/12] bridge: Add the ability to configure untagged
vlans
On Tue, Dec 18, 2012 at 02:01:00PM -0500, Vlad Yasevich wrote:
> A user may designate a certain vlan as untagged. This means that
> any ingress frame is assigned to this vlan and any forwarding decisions
> are made with this vlan in mind. On egress, any frames tagged/labeled
> with untagged vlan have the vlan tag removed and are send as regular
> ethernet frames.
>
> Signed-off-by: Vlad Yasevich <vyasevic@...hat.com>
> ---
> include/uapi/linux/if_bridge.h | 3 +
> net/bridge/br_if.c | 146 +++++++++++++++++++++++++++++++++++++---
> net/bridge/br_netlink.c | 6 +-
> net/bridge/br_private.h | 2 +
> 4 files changed, 144 insertions(+), 13 deletions(-)
>
> diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
> index d0b4f5c..988d858 100644
> --- a/include/uapi/linux/if_bridge.h
> +++ b/include/uapi/linux/if_bridge.h
> @@ -127,6 +127,9 @@ enum {
> BR_VLAN_DEL,
> };
>
> +#define BRIDGE_VLAN_INFO_MASTER 1
> +#define BRIDGE_VLAN_INFO_UNTAGGED 2
> +
> struct bridge_vlan_info {
> u16 op_code;
> u16 flags;
> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
> index 57bbb35..14563fb 100644
> --- a/net/bridge/br_if.c
> +++ b/net/bridge/br_if.c
> @@ -108,6 +108,34 @@ static void br_vlan_put(struct net_bridge_vlan *vlan)
> br_vlan_destroy(vlan);
> }
>
> +/* Must be protected by RTNL */
> +static void br_vlan_add_untagged(struct net_bridge *br,
> + struct net_bridge_vlan *vlan)
> +{
> + ASSERT_RTNL();
> + if (br->untagged == vlan)
> + return;
> + else if (br->untagged) {
> + /* Untagged vlan is already set on the master,
> + * so drop the ref since we'll be replacing it.
> + */
> + br_vlan_put(br->untagged);
> + }
> + br_vlan_hold(vlan);
> + rcu_assign_pointer(br->untagged, vlan);
> +}
> +
> +/* Must be protected by RTNL */
> +static void br_vlan_del_untagged(struct net_bridge *br,
> + struct net_bridge_vlan *vlan)
> +{
> + ASSERT_RTNL();
> + if (br->untagged == vlan) {
> + br_vlan_put(vlan);
> + rcu_assign_pointer(br->untagged, NULL);
> + }
> +}
> +
> struct net_bridge_vlan *br_vlan_find(struct net_bridge *br, u16 vid)
> {
> struct net_bridge_vlan *vlan;
> @@ -132,7 +160,7 @@ struct net_bridge_vlan *br_vlan_add(struct net_bridge *br, u16 vid,
>
> vlan = br_vlan_find(br, vid);
> if (vlan)
> - return vlan;
> + goto untagged;
>
> vlan = kzalloc(sizeof(struct net_bridge_vlan), GFP_KERNEL);
> if (!vlan)
> @@ -141,7 +169,7 @@ struct net_bridge_vlan *br_vlan_add(struct net_bridge *br, u16 vid,
> vlan->vid = vid;
> atomic_set(&vlan->refcnt, 1);
>
> - if (flags & BRIDGE_FLAGS_SELF) {
> + if (flags & BRIDGE_VLAN_INFO_MASTER) {
> /* Set bit 0 that is associated with the bridge master
> * device. Port numbers start with 1.
> */
> @@ -149,15 +177,24 @@ struct net_bridge_vlan *br_vlan_add(struct net_bridge *br, u16 vid,
> }
>
> hlist_add_head_rcu(&vlan->hlist, &br->vlan_hlist[br_vlan_hash(vid)]);
> +
> +untagged:
> + if (flags & BRIDGE_VLAN_INFO_UNTAGGED)
> + br_vlan_add_untagged(br, vlan);
> +
> return vlan;
> }
>
> /* Must be protected by RTNL */
> -static void br_vlan_del(struct net_bridge_vlan *vlan, u16 flags)
> +static void br_vlan_del(struct net_bridge *br, struct net_bridge_vlan *vlan,
> + u16 flags)
> {
> ASSERT_RTNL();
>
> - if (flags & BRIDGE_FLAGS_SELF) {
> + if (flags & BRIDGE_VLAN_INFO_UNTAGGED)
> + br_vlan_del_untagged(br, vlan);
> +
> + if (flags & BRIDGE_VLAN_INFO_MASTER) {
> /* Clear bit 0 that is associated with the bridge master
> * device.
> */
> @@ -172,6 +209,14 @@ static void br_vlan_del(struct net_bridge_vlan *vlan, u16 flags)
>
> vlan->vid = BR_INVALID_VID;
>
> + /* If, for whatever reason, bridge still has a ref on this vlan
> + * through the @untagged pointer, drop that ref and clear untagged.
> + */
> + if (br->untagged == vlan) {
> + br_vlan_put(vlan);
> + rcu_assign_pointer(br->untagged, NULL);
Is something doing an rcu sync after this point?
If yes maybe add a comment saying where it is, if not - some rcu read
side could still be using it through this pointer.
> + }
> +
> /* Drop the self-ref to trigger descrution. */
> br_vlan_put(vlan);
> }
> @@ -187,7 +232,7 @@ int br_vlan_delete(struct net_bridge *br, u16 vid, u16 flags)
> if (!vlan)
> return -ENOENT;
>
> - br_vlan_del(vlan, flags);
> + br_vlan_del(br, vlan, flags);
> return 0;
> }
>
> @@ -204,7 +249,9 @@ static void br_vlan_flush(struct net_bridge *br)
> for (i = 0; i < BR_VID_HASH_SIZE; i++) {
> hlist_for_each_entry_safe(vlan, node, tmp,
> &br->vlan_hlist[i], hlist) {
> - br_vlan_del(vlan, BRIDGE_FLAGS_SELF);
> + br_vlan_del(br, vlan,
> + (BRIDGE_VLAN_INFO_MASTER |
> + BRIDGE_VLAN_INFO_UNTAGGED));
> }
> }
> }
> @@ -224,10 +271,70 @@ struct net_port_vlan *nbp_vlan_find(const struct net_bridge_port *p, u16 vid)
> return NULL;
> }
>
> +static int nbp_vlan_add_untagged(struct net_bridge_port *p,
> + struct net_bridge_vlan *vlan,
> + u16 flags)
> +{
> + struct net_device *dev = p->dev;
> +
> + if (p->untagged) {
> + /* Port already has untagged vlan set. Drop the ref
> + * to the old one since we'll be replace it.
> + */
> + br_vlan_put(p->untagged);
> + } else {
> + int err;
> +
> + /* Add vid 0 to filter if filter is available. */
> + if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
> + dev->netdev_ops->ndo_vlan_rx_add_vid &&
> + dev->netdev_ops->ndo_vlan_rx_kill_vid) {
> + err = dev->netdev_ops->ndo_vlan_rx_add_vid(dev, 0);
> + if (err)
> + return err;
> + }
> + }
> +
> + /* This VLAN is handled as untagged/native. Save an
> + * additional ref.
> + */
> + br_vlan_hold(vlan);
> + rcu_assign_pointer(p->untagged, vlan);
> +
> + return 0;
> +}
> +
> +static void nbp_vlan_delete_untagged(struct net_bridge_port *p,
> + struct net_bridge_vlan *vlan)
> +{
> + if (p->untagged != vlan)
> + return;
> +
> + /* Remove VLAN from the device filter if it is supported. */
> + if ((p->dev->features & NETIF_F_HW_VLAN_FILTER) &&
> + p->dev->netdev_ops->ndo_vlan_rx_kill_vid) {
> + int err;
> +
> + err = p->dev->netdev_ops->ndo_vlan_rx_kill_vid(p->dev, 0);
> + if (err) {
> + pr_warn("failed to kill vid %d for device %s\n",
> + vlan->vid, p->dev->name);
> + }
> + }
> +
> + /* If this VLAN is currently functioning as untagged, clear it.
> + * It's safe to drop the refcount, since the vlan is still held
> + * by the port.
> + */
> + br_vlan_put(vlan);
> + rcu_assign_pointer(p->untagged, NULL);
> +
> +}
> +
> /* Must be protected by RTNL */
> int nbp_vlan_add(struct net_bridge_port *p, u16 vid, u16 flags)
> {
> - struct net_port_vlan *pve;
> + struct net_port_vlan *pve = NULL;
> struct net_bridge_vlan *vlan;
> struct net_device *dev = p->dev;
> int err;
> @@ -275,11 +382,21 @@ int nbp_vlan_add(struct net_bridge_port *p, u16 vid, u16 flags)
> set_bit(p->port_no, vlan->port_bitmap);
>
> list_add_tail_rcu(&pve->list, &p->vlan_list);
> +
> + if (flags & BRIDGE_VLAN_INFO_UNTAGGED) {
> + err = nbp_vlan_add_untagged(p, vlan, flags);
> + if (err)
> + goto del_vlan;
> + }
> +
> return 0;
>
> clean_up:
> kfree(pve);
> - br_vlan_del(vlan, flags);
> + br_vlan_del(p->br, vlan, flags);
> + return err;
> +del_vlan:
> + nbp_vlan_delete(p, vid, flags);
> return err;
> }
>
> @@ -296,6 +413,9 @@ int nbp_vlan_delete(struct net_bridge_port *p, u16 vid, u16 flags)
> if (!pve)
> return -ENOENT;
>
> + if (flags & BRIDGE_VLAN_INFO_UNTAGGED)
> + nbp_vlan_delete_untagged(p, pve->vlan);
> +
> /* Remove VLAN from the device filter if it is supported. */
> if ((dev->features & NETIF_F_HW_VLAN_FILTER) &&
> dev->netdev_ops->ndo_vlan_rx_kill_vid) {
> @@ -306,6 +426,7 @@ int nbp_vlan_delete(struct net_bridge_port *p, u16 vid, u16 flags)
> pr_warn("failed to kill vid %d for device %s\n",
> vid, dev->name);
> }
> +
> pve->vid = BR_INVALID_VID;
>
> vlan = pve->vlan;
> @@ -316,7 +437,7 @@ int nbp_vlan_delete(struct net_bridge_port *p, u16 vid, u16 flags)
> list_del_rcu(&pve->list);
> kfree_rcu(pve, rcu);
>
> - br_vlan_del(vlan, flags);
> + br_vlan_del(p->br, vlan, flags);
>
> return 0;
> }
> @@ -328,8 +449,11 @@ static void nbp_vlan_flush(struct net_bridge_port *p)
>
> ASSERT_RTNL();
>
> - list_for_each_entry_safe(pve, tmp, &p->vlan_list, list)
> - nbp_vlan_delete(p, pve->vid, BRIDGE_FLAGS_SELF);
> + list_for_each_entry_safe(pve, tmp, &p->vlan_list, list) {
> + nbp_vlan_delete(p, pve->vid,
> + (BRIDGE_VLAN_INFO_MASTER |
> + BRIDGE_VLAN_INFO_UNTAGGED));
> + }
> }
>
> static void release_nbp(struct kobject *kobj)
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 9cf2879..1b302ce 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -199,7 +199,8 @@ static int br_afspec(struct net_bridge *br, struct net_bridge_port *p,
> if (p)
> err = nbp_vlan_add(p, vinfo->vid, vinfo->flags);
> else {
> - u16 flags = vinfo->flags | BRIDGE_FLAGS_SELF;
> + u16 flags = vinfo->flags |
> + BRIDGE_VLAN_INFO_MASTER;
> if (!br_vlan_add(br, vinfo->vid, flags))
> err = -ENOMEM;
> }
> @@ -210,7 +211,8 @@ static int br_afspec(struct net_bridge *br, struct net_bridge_port *p,
> err = nbp_vlan_delete(p, vinfo->vid,
> vinfo->flags);
> else {
> - u16 flags = vinfo->flags | BRIDGE_FLAGS_SELF;
> + u16 flags = vinfo->flags |
> + BRIDGE_VLAN_INFO_MASTER;
> err = br_vlan_delete(br, vinfo->vid, flags);
> }
> break;
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index cc75212..9328463 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -179,6 +179,7 @@ struct net_bridge_port
> struct netpoll *np;
> #endif
> struct list_head vlan_list;
> + struct net_bridge_vlan __rcu *untagged;
> };
>
> #define br_port_exists(dev) (dev->priv_flags & IFF_BRIDGE_PORT)
> @@ -298,6 +299,7 @@ struct net_bridge
> struct timer_list gc_timer;
> struct kobject *ifobj;
> struct hlist_head vlan_hlist[BR_VID_HASH_SIZE];
> + struct net_bridge_vlan __rcu *untagged;
> };
>
> struct br_input_skb_cb {
> --
> 1.7.7.6
--
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