netdev - [PATCH v2 5/5] ipvlan: set dev_id for l2 ports to generate unique IPv6 addresses

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 03 Jul 2015 15:58:41 +0300
From:	Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:	netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>
Cc:	Mahesh Bandewar <maheshb@...gle.com>, Jiri Benc <jbenc@...hat.com>
Subject: [PATCH v2 5/5] ipvlan: set dev_id for l2 ports to generate unique
 IPv6 addresses

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 <khlebnikov@...dex-team.ru>
---
 Documentation/networking/ipvlan.txt |   11 ++++++++++-
 drivers/net/ipvlan/ipvlan.h         |    1 +
 drivers/net/ipvlan/ipvlan_main.c    |   19 +++++++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/ipvlan.txt b/Documentation/networking/ipvlan.txt
index cf996394e466..d1123de81469 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).
+
+	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
diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h
index a23069aec4d9..0d1f5e8ed75f 100644
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h
@@ -98,6 +98,7 @@ struct ipvl_port {
 	int			count;
 	u16			mode;
 	spinlock_t		addr_lock;
+	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 83a936f76248..d465b2c287cb 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);
 
 	skb_queue_head_init(&port->backlog);
 	INIT_WORK(&port->wq, ipvlan_process_multicast);
@@ -78,6 +79,7 @@ static void ipvlan_port_destroy(struct net_device *dev)
 	netdev_rx_handler_unregister(dev);
 	cancel_work_sync(&port->wq);
 	__skb_queue_purge(&port->backlog);
+	ida_destroy(&port->ida);
 	kfree_rcu(port, rcu);
 }
 
@@ -481,6 +483,18 @@ 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;
@@ -517,6 +531,11 @@ static void ipvlan_link_delete(struct net_device *dev, struct list_head *head)
 	}
 	ipvlan_addr_unlock_bh(ipvlan);
 
+	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);

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html