On 20.05.2015 02:59, Mahesh Bandewar wrote:
On Thu, May 14, 2015 at 6:56 AM, Konstantin Khlebnikov
<khlebni...@yandex-team.ru> wrote:
All ipvlan ports use one MAC address, this way ipv6 RA tries to assign
one ipv6 address to all of them. This patch assigns unique dev_id to each
ipvlan port. This field is used instead of common FF-FE in Modified EUI-64.
Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
---
Documentation/networking/ipvlan.txt | 12 +++++++++++-
drivers/net/ipvlan/ipvlan.h | 1 +
drivers/net/ipvlan/ipvlan_main.c | 20 ++++++++++++++++++++
3 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/ipvlan.txt
b/Documentation/networking/ipvlan.txt
index cf996394e466..cb0b777bce58 100644
--- a/Documentation/networking/ipvlan.txt
+++ b/Documentation/networking/ipvlan.txt
@@ -24,7 +24,7 @@ using IProute2/ip utility.
ip link add link <master-dev> <slave-dev> type ipvlan mode { l2 | L3 }
- e.g. ip link add link ipvl0 eth0 type ipvlan mode l2
+ e.g. ip link add link eth0 ipvl0 type ipvlan mode l2
4. Operating modes:
@@ -41,6 +41,15 @@ slave device and packets are switched and queued to the
master device to send
out. In this mode the slaves will RX/TX multicast and broadcast (if
applicable)
as well.
+ In L2 mode slave devices receive Router Advertisements from the network
+and perform autoconfiguration as well as master device. Each port has unique
+16-bit device id which is used for filling octets 4-5 of Modified EUI-64.
+That gives 65533 addresses (FF-FE used by master, FF-FF/00-00 reserved/not
used).
+
This is nice, thanks for fixing this! However how is "unique" id
guaranteed? Especially when multiple virtual drivers are stacked? Not
necessarily all of them may use the dev_id, but to avoid any possible
collision, shouldn't the device hierarchy (especially lower_dev) be
traversed before settling on the initial value?
Well, uniqueness isn't guaranteed but that should work in most cases.
ipv6 anyway checks for duplicate addresses after configuration.
As I see creation of ipvlan on ipvlan just creates slave at original
master device, so this will work as expected. And ipvlan cannot share
physical device with bonding/bridge/macvlan, so I don't see how to
stack more than one layer of ipvlans accidentally.
+ Also lower half of IPv6 address could be set as interface token:
+
+ ip token set ::aaaa:bbbb:cccc:dddd dev ipvl0
+
4.2 L3 mode:
In this mode TX processing upto L3 happens on the stack instance
attached
to the slave device and packets are switched to the stack instance of the
@@ -105,3 +114,4 @@ namespace where L2 on the slave could be changed / misused.
(4) ip -4 addr add 127.0.0.1 dev lo
(5) ip -4 addr add $IPADDR dev ipvl1
(6) ip -4 route add default via $ROUTER dev ipvl1
+
diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h
index 54549a6223dd..1ebab84e7a0e 100644
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h
@@ -95,6 +95,7 @@ struct ipvl_port {
struct rcu_head rcu;
int count;
u16 mode;
+ struct ida ida;
};
static inline struct ipvl_port *ipvlan_port_get_rcu(const struct net_device
*d)
diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 0cafd3e6f02d..dee0e8441150 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -53,6 +53,7 @@ static int ipvlan_port_create(struct net_device *dev)
INIT_LIST_HEAD(&port->ipvlans);
for (idx = 0; idx < IPVLAN_HASH_SIZE; idx++)
INIT_HLIST_HEAD(&port->hlhead[idx]);
+ ida_init(&port->ida);
err = netdev_rx_handler_register(dev, ipvlan_handle_frame, port);
if (err)
@@ -72,6 +73,7 @@ static void ipvlan_port_destroy(struct net_device *dev)
dev->priv_flags &= ~IFF_IPVLAN_MASTER;
netdev_rx_handler_unregister(dev);
+ ida_destroy(&port->ida);
kfree_rcu(port, rcu);
}
@@ -484,6 +486,18 @@ static int ipvlan_link_new(struct net *src_net, struct
net_device *dev,
*/
memcpy(dev->dev_addr, phy_dev->dev_addr, ETH_ALEN);
+ if (port->mode == IPVLAN_MODE_L2) {
+ /*
+ * IPv6 addrconf uses it to produce unique addresses,
+ * see function addrconf_ifid_eui48.
+ */
+ err = ida_simple_get(&port->ida, 1, 0xFFFE, GFP_KERNEL);
+ if (err > 0)
+ dev->dev_id = err;
+ else if (err != -ENOSPC)
+ goto ipvlan_destroy_port;
+ }
+
dev->priv_flags |= IFF_IPVLAN_SLAVE;
port->count += 1;
@@ -518,6 +532,12 @@ static void ipvlan_link_delete(struct net_device *dev,
struct list_head *head)
list_del(&addr->anode);
}
}
+
+ if (dev->dev_id) {
+ ida_simple_remove(&ipvlan->port->ida, dev->dev_id);
+ dev->dev_id = 0;
+ }
+
list_del_rcu(&ipvlan->pnode);
unregister_netdevice_queue(dev, head);
netdev_upper_dev_unlink(ipvlan->phy_dev, dev);
--
Konstantin
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