Commit 28690e53 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

rtnetlink: Add peer_type in struct rtnl_link_ops. 



In ops->newlink(), veth, vxcan, and netkit call rtnl_link_get_net() with
a net pointer, which is the first argument of ->newlink().

rtnl_link_get_net() could return another netns based on IFLA_NET_NS_PID
and IFLA_NET_NS_FD in the peer device's attributes.

We want to get it and fill rtnl_nets->nets[] in advance in rtnl_newlink()
for per-netns RTNL.

All of the three get the peer netns in the same way:

  1. Call rtnl_nla_parse_ifinfomsg()
  2. Call ops->validate() (vxcan doesn't have)
  3. Call rtnl_link_get_net_tb()

Let's add a new field peer_type to struct rtnl_link_ops and prefetch
netns in the peer ifla to add it to rtnl_nets in rtnl_newlink().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-6-kuniyu@amazon.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent cbaaa632

include/net/rtnetlink.h

+2 −0
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh) 
 *	@srcu: Used internally

 *	@kind: Identifier

 *	@netns_refund: Physical device, move to init_net on netns exit

 *	@peer_type: Peer device specific netlink attribute number (e.g. VETH_INFO_PEER)

 *	@maxtype: Highest device specific netlink attribute number

 *	@policy: Netlink policy for device specific attribute validation

 *	@validate: Optional validation function for netlink/changelink parameters
@@ -116,6 +117,7 @@ struct rtnl_link_ops { 
	void			(*setup)(struct net_device *dev);



	bool			netns_refund;

	const u16		peer_type;

	unsigned int		maxtype;

	const struct nla_policy	*policy;

	int			(*validate)(struct nlattr *tb[],

net/core/rtnetlink.c

+51 −4
Original line number Diff line number Diff line
@@ -2492,9 +2492,10 @@ int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer, 
}

EXPORT_SYMBOL(rtnl_nla_parse_ifinfomsg);



struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[])

static struct net *rtnl_link_get_net_ifla(struct nlattr *tb[])

{

	struct net *net;

	struct net *net = NULL;



	/* Examine the link attributes and figure out which

	 * network namespace we are talking about.

	 */
@@ -2502,8 +2503,17 @@ struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]) 
		net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID]));

	else if (tb[IFLA_NET_NS_FD])

		net = get_net_ns_by_fd(nla_get_u32(tb[IFLA_NET_NS_FD]));

	else



	return net;

}



struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[])

{

	struct net *net = rtnl_link_get_net_ifla(tb);



	if (!net)

		net = get_net(src_net);



	return net;

}

EXPORT_SYMBOL(rtnl_link_get_net);
@@ -3765,6 +3775,37 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm, 
	goto out;

}



static int rtnl_add_peer_net(struct rtnl_nets *rtnl_nets,

			     const struct rtnl_link_ops *ops,

			     struct nlattr *data[],

			     struct netlink_ext_ack *extack)

{

	struct nlattr *tb[IFLA_MAX + 1];

	struct net *net;

	int err;



	if (!data || !data[ops->peer_type])

		return 0;



	err = rtnl_nla_parse_ifinfomsg(tb, data[ops->peer_type], extack);

	if (err < 0)

		return err;



	if (ops->validate) {

		err = ops->validate(tb, NULL, extack);

		if (err < 0)

			return err;

	}



	net = rtnl_link_get_net_ifla(tb);

	if (IS_ERR(net))

		return PTR_ERR(net);

	if (net)

		rtnl_nets_add(rtnl_nets, net);



	return 0;

}



static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			  const struct rtnl_link_ops *ops,

			  struct net *tgt_net, struct net *link_net,
@@ -3893,12 +3934,18 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
			if (ret < 0)

				goto put_ops;

		}



		if (ops->peer_type) {

			ret = rtnl_add_peer_net(&rtnl_nets, ops, data, extack);

			if (ret < 0)

				goto put_ops;

		}

	}



	tgt_net = rtnl_link_get_net_capable(skb, sock_net(skb->sk), tb, CAP_NET_ADMIN);

	if (IS_ERR(tgt_net)) {

		ret = PTR_ERR(tgt_net);

		goto put_ops;

		goto put_net;

	}



	rtnl_nets_add(&rtnl_nets, tgt_net);