From 00e77ed8e64d5f271c1f015c7153545980d48a76 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Sat, 12 Jun 2021 10:20:55 +0200 Subject: [PATCH] rtnetlink: add IFLA_PARENT_[DEV|DEV_BUS]_NAME 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: 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 Signed-off-by: Sergey Ryazanov Co-developed-by: Loic Poulain Signed-off-by: Loic Poulain Suggested-by: Sergey Ryazanov Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- include/uapi/linux/if_link.h | 7 +++++++ net/core/rtnetlink.c | 10 ++++++++++ 2 files changed, 17 insertions(+) diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index a5a7f0e..4882e81 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -341,6 +341,13 @@ enum { IFLA_ALT_IFNAME, /* Alternative ifname */ IFLA_PERM_ADDRESS, 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 }; diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 92c3e43..170e97f 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1821,6 +1821,16 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, if (rtnl_fill_prop_list(skb, dev)) 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); return 0; -- 2.7.4