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rtnetlink: add IFLA_PARENT_[DEV|DEV_BUS]_NAME

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In some cases, for example in the upcoming WWAN framework changes,
there's no natural "parent netdev", so sometimes dummy netdevs are
created or similar. IFLA_PARENT_DEV_NAME is a new attribute intended to
contain a device (sysfs, struct device) name that can be used instead
when creating a new netdev, if the rtnetlink family implements it.

As suggested by Parav Pandit, we also introduce IFLA_PARENT_DEV_BUS_NAME
attribute in order to uniquely identify a device on the system (with
bus/name pair).

ip-link(8) support for the generic parent device attributes will help
us avoid code duplication, so no other link type will require a custom
code to handle the parent name attribute. E.g. the WWAN interface
creation command will looks like this:

$ ip link add wwan0-1 parent-dev wwan0 type wwan channel-id 1

So, some future subsystem (or driver) FOO will have an interface
creation command that looks like this:

$ ip link add foo1-3 parent-dev foo1 type foo bar-id 3 baz-type Y

Below is an example of dumping link info of a random device with these
new attributes:

$ ip --details link show wlp0s20f3
  4: wlp0s20f3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
     state UP mode DORMANT group default qlen 1000
     ...
     parent_bus pci parent_dev 0000:00:14.3

Co-developed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Co-developed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Suggested-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Johannes Berg
2021-06-12 10:20:55 +02:00
committed by David S. Miller
parent 8c713dc93c
commit 00e77ed8e6
2 changed files with 17 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
include/uapi/linux/if_link.h
View File

@@ -341,6 +341,13 @@ enum {
IFLA_ALT_IFNAME, /* Alternative ifname */ IFLA_ALT_IFNAME, /* Alternative ifname */
IFLA_PERM_ADDRESS, IFLA_PERM_ADDRESS,
IFLA_PROTO_DOWN_REASON, IFLA_PROTO_DOWN_REASON,
/* device (sysfs) name as parent, used instead
* of IFLA_LINK where there's no parent netdev
*/
IFLA_PARENT_DEV_NAME,
IFLA_PARENT_DEV_BUS_NAME,
__IFLA_MAX __IFLA_MAX
}; };

10
net/core/rtnetlink.c
View File

@@ -1821,6 +1821,16 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
if (rtnl_fill_prop_list(skb, dev)) if (rtnl_fill_prop_list(skb, dev))
goto nla_put_failure; goto nla_put_failure;
if (dev->dev.parent &&
nla_put_string(skb, IFLA_PARENT_DEV_NAME,
dev_name(dev->dev.parent)))
goto nla_put_failure;
if (dev->dev.parent && dev->dev.parent->bus &&
nla_put_string(skb, IFLA_PARENT_DEV_BUS_NAME,
dev->dev.parent->bus->name))
goto nla_put_failure;
nlmsg_end(skb, nlh); nlmsg_end(skb, nlh);
return 0; return 0;