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macvlan: Introduce 'passthru' mode to takeover the underlying device

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With the current default 'vepa' mode, a KVM guest using virtio with
macvtap backend has the following limitations.
- cannot change/add a mac address on the guest virtio-net
- cannot create a vlan device on the guest virtio-net
- cannot enable promiscuous mode on guest virtio-net

To address these limitations, this patch introduces a new mode called
'passthru' when creating a macvlan device which allows takeover of the
underlying device and passing it to a guest using virtio with macvtap
backend.

Only one macvlan device is allowed in passthru mode and it inherits
the mac address from the underlying device and sets it in promiscuous
mode to receive and forward all the packets.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>

-------------------------------------------------------------------------
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sridhar Samudrala 2010-10-28 13:10:50 +00:00 committed by David S. Miller
parent e5700c740d
commit eb06acdc85
2 changed files with 33 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/net/macvlan.c
View File

@ -38,6 +38,7 @@ struct macvlan_port {
struct hlist_head vlan_hash[MACVLAN_HASH_SIZE];
struct list_head vlans;
struct rcu_head rcu;
bool passthru;
};
#define macvlan_port_get_rcu(dev) \
@ -169,6 +170,7 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
macvlan_broadcast(skb, port, NULL,
MACVLAN_MODE_PRIVATE |
MACVLAN_MODE_VEPA |
MACVLAN_MODE_PASSTHRU|
MACVLAN_MODE_BRIDGE);
else if (src->mode == MACVLAN_MODE_VEPA)
/* flood to everyone except source */
@ -185,7 +187,10 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
return skb;
}
vlan = macvlan_hash_lookup(port, eth->h_dest);
if (port->passthru)
vlan = list_first_entry(&port->vlans, struct macvlan_dev, list);
else
vlan = macvlan_hash_lookup(port, eth->h_dest);
if (vlan == NULL)
return skb;
@ -288,6 +293,11 @@ static int macvlan_open(struct net_device *dev)
struct net_device *lowerdev = vlan->lowerdev;
int err;
if (vlan->port->passthru) {
dev_set_promiscuity(lowerdev, 1);
goto hash_add;
}
err = -EBUSY;
if (macvlan_addr_busy(vlan->port, dev->dev_addr))
goto out;
@ -300,6 +310,8 @@ static int macvlan_open(struct net_device *dev)
if (err < 0)
goto del_unicast;
}
hash_add:
macvlan_hash_add(vlan);
return 0;
@ -314,12 +326,18 @@ static int macvlan_stop(struct net_device *dev)
struct macvlan_dev *vlan = netdev_priv(dev);
struct net_device *lowerdev = vlan->lowerdev;
if (vlan->port->passthru) {
dev_set_promiscuity(lowerdev, -1);
goto hash_del;
}
dev_mc_unsync(lowerdev, dev);
if (dev->flags & IFF_ALLMULTI)
dev_set_allmulti(lowerdev, -1);
dev_uc_del(lowerdev, dev->dev_addr);
hash_del:
macvlan_hash_del(vlan);
return 0;
}
@ -559,6 +577,7 @@ static int macvlan_port_create(struct net_device *dev)
if (port == NULL)
return -ENOMEM;
port->passthru = false;
port->dev = dev;
INIT_LIST_HEAD(&port->vlans);
for (i = 0; i < MACVLAN_HASH_SIZE; i++)
@ -603,6 +622,7 @@ static int macvlan_validate(struct nlattr *tb[], struct nlattr *data[])
case MACVLAN_MODE_PRIVATE:
case MACVLAN_MODE_VEPA:
case MACVLAN_MODE_BRIDGE:
case MACVLAN_MODE_PASSTHRU:
break;
default:
return -EINVAL;
@ -652,6 +672,10 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
}
port = macvlan_port_get(lowerdev);
/* Only 1 macvlan device can be created in passthru mode */
if (port->passthru)
return -EINVAL;
vlan->lowerdev = lowerdev;
vlan->dev = dev;
vlan->port = port;
@ -662,6 +686,13 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
if (data && data[IFLA_MACVLAN_MODE])
vlan->mode = nla_get_u32(data[IFLA_MACVLAN_MODE]);
if (vlan->mode == MACVLAN_MODE_PASSTHRU) {
if (!list_empty(&port->vlans))
return -EINVAL;
port->passthru = true;
memcpy(dev->dev_addr, lowerdev->dev_addr, ETH_ALEN);
}
err = register_netdevice(dev);
if (err < 0)
goto destroy_port;

1
include/linux/if_link.h
View File

@ -259,6 +259,7 @@ enum macvlan_mode {
MACVLAN_MODE_PRIVATE = 1, /* don't talk to other macvlans */
MACVLAN_MODE_VEPA = 2, /* talk to other ports through ext bridge */
MACVLAN_MODE_BRIDGE = 4, /* talk to bridge ports directly */
MACVLAN_MODE_PASSTHRU = 8,/* take over the underlying device */
};
/* SR-IOV virtual function management section */