This patch adds a new attribute (IFLA_LINK_NETNSID) which contains the 'link'
netns id when this netns is different from the netns where the interface
stands (for example for x-net interfaces like ip tunnels). When there is no id,
because user ns of link netns and interface netns is not the same, we put 0
into this attribute (id 0 is not valid) to indicate to userland that the link
netns is different from the interface netns. Hence, userland knows that some
information like IFLA_LINK are not interpretable.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
---
include/net/rtnetlink.h | 2 ++
include/uapi/linux/if_link.h | 1 +
net/core/rtnetlink.c | 22 ++++++++++++++++++++++
3 files changed, 25 insertions(+)
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index e21b9f9653c0..6c6d5393fc34 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -46,6 +46,7 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
* to create when creating a new device.
* @get_num_rx_queues: Function to determine number of receive queues
* to create when creating a new device.
+ * @get_link_net: Function to get the i/o netns of the device
*/
struct rtnl_link_ops {
struct list_head list;
@@ -93,6 +94,7 @@ struct rtnl_link_ops {
int (*fill_slave_info)(struct sk_buff *skb,
const struct net_device *dev,
const struct net_device *slave_dev);
+ struct net *(*get_link_net)(const struct net_device *dev);
};
int __rtnl_link_register(struct rtnl_link_ops *ops);
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index c80f95f6ee78..21dd2bcb295f 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -145,6 +145,7 @@ enum {
IFLA_CARRIER,
IFLA_PHYS_PORT_ID,
IFLA_CARRIER_CHANGES,
+ IFLA_LINK_NETNSID,
__IFLA_MAX
};
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a6882686ca3a..99ed83c62685 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -862,6 +862,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
+ nla_total_size(1) /* IFLA_OPERSTATE */
+ nla_total_size(1) /* IFLA_LINKMODE */
+ nla_total_size(4) /* IFLA_CARRIER_CHANGES */
+ + nla_total_size(4) /* IFLA_LINK_NETNSID */
+ nla_total_size(ext_filter_mask
& RTEXT_FILTER_VF ? 4 : 0) /* IFLA_NUM_VF */
+ rtnl_vfinfo_size(dev, ext_filter_mask) /* IFLA_VFINFO_LIST */
@@ -1134,6 +1135,27 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
goto nla_put_failure;
}
+ if (dev->rtnl_link_ops &&
+ dev->rtnl_link_ops->get_link_net) {
+ struct net *link_net = dev->rtnl_link_ops->get_link_net(dev);
+
+ if (!net_eq(dev_net(dev), link_net)) {
+ int id = peernet2id(dev_net(dev), link_net);
+
+ /* If the link netns is not in the same user ns, put id
+ * 0 in IFLA_LINK_NETNSID to indicate to userland that
+ * the link netns is not the current netns, but that it
+ * don't have access to it.
+ */
+ if (id == -EPERM)
+ id = 0;
+
+ if (id >= 0 &&
+ nla_put_u32(skb, IFLA_LINK_NETNSID, id))
+ goto nla_put_failure;
+ }
+ }
+
if (!(af_spec = nla_nest_start(skb, IFLA_AF_SPEC)))
goto nla_put_failure;
--
2.1.0
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