Commit f8ff182c authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

rtnetlink: Link address family API 



Each net_device contains address family specific data such as
per device settings and statistics. We already expose this data
via procfs/sysfs and partially netlink.

The netlink method requires the requester to send one RTM_GETLINK
request for each address family it wishes to receive data of
and then merge this data itself.

This patch implements a new API which combines all address family
specific link data in a new netlink attribute IFLA_AF_SPEC.
IFLA_AF_SPEC contains a sequence of nested attributes, one for each
address family which in turn defines the structure of its own
attribute. Example:

   [IFLA_AF_SPEC] = {
       [AF_INET] = {
           [IFLA_INET_CONF] = ...,
       },
       [AF_INET6] = {
           [IFLA_INET6_FLAGS] = ...,
           [IFLA_INET6_CONF] = ...,
       }
   }

The API also allows for address families to implement a function
which parses the IFLA_AF_SPEC attribute sent by userspace to
implement address family specific link options.

Signed-off-by: default avatarThomas Graf <tgraf@infradead.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d67ef35f

include/linux/if_link.h

+19 −0
Original line number Diff line number Diff line
@@ -80,6 +80,24 @@ struct rtnl_link_ifmap { 
	__u8	port;

};



/*

 * IFLA_AF_SPEC

 *   Contains nested attributes for address family specific attributes.

 *   Each address family may create a attribute with the address family

 *   number as type and create its own attribute structure in it.

 *

 *   Example:

 *   [IFLA_AF_SPEC] = {

 *       [AF_INET] = {

 *           [IFLA_INET_CONF] = ...,

 *       },

 *       [AF_INET6] = {

 *           [IFLA_INET6_FLAGS] = ...,

 *           [IFLA_INET6_CONF] = ...,

 *       }

 *   }

 */



enum {

	IFLA_UNSPEC,

	IFLA_ADDRESS,
@@ -116,6 +134,7 @@ enum { 
	IFLA_STATS64,

	IFLA_VF_PORTS,

	IFLA_PORT_SELF,

	IFLA_AF_SPEC,

	__IFLA_MAX

};

include/net/rtnetlink.h

+31 −0
Original line number Diff line number Diff line
@@ -83,6 +83,37 @@ extern void __rtnl_link_unregister(struct rtnl_link_ops *ops); 
extern int	rtnl_link_register(struct rtnl_link_ops *ops);

extern void	rtnl_link_unregister(struct rtnl_link_ops *ops);



/**

 * 	struct rtnl_af_ops - rtnetlink address family operations

 *

 *	@list: Used internally

 * 	@family: Address family

 * 	@fill_link_af: Function to fill IFLA_AF_SPEC with address family

 * 		       specific netlink attributes.

 * 	@get_link_af_size: Function to calculate size of address family specific

 * 			   netlink attributes exlusive the container attribute.

 * 	@parse_link_af: Function to parse a IFLA_AF_SPEC attribute and modify

 *			net_device accordingly.

 */

struct rtnl_af_ops {

	struct list_head	list;

	int			family;



	int			(*fill_link_af)(struct sk_buff *skb,

						const struct net_device *dev);

	size_t			(*get_link_af_size)(const struct net_device *dev);



	int			(*parse_link_af)(struct net_device *dev,

						 const struct nlattr *attr);

};



extern int	__rtnl_af_register(struct rtnl_af_ops *ops);

extern void	__rtnl_af_unregister(struct rtnl_af_ops *ops);



extern int	rtnl_af_register(struct rtnl_af_ops *ops);

extern void	rtnl_af_unregister(struct rtnl_af_ops *ops);





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

extern struct net_device *rtnl_create_link(struct net *src_net, struct net *net,

	char *ifname, const struct rtnl_link_ops *ops, struct nlattr *tb[]);

net/core/rtnetlink.c

+145 −2
Original line number Diff line number Diff line
@@ -362,6 +362,95 @@ static size_t rtnl_link_get_size(const struct net_device *dev) 
	return size;

}



static LIST_HEAD(rtnl_af_ops);



static const struct rtnl_af_ops *rtnl_af_lookup(const int family)

{

	const struct rtnl_af_ops *ops;



	list_for_each_entry(ops, &rtnl_af_ops, list) {

		if (ops->family == family)

			return ops;

	}



	return NULL;

}



/**

 * __rtnl_af_register - Register rtnl_af_ops with rtnetlink.

 * @ops: struct rtnl_af_ops * to register

 *

 * The caller must hold the rtnl_mutex.

 *

 * Returns 0 on success or a negative error code.

 */

int __rtnl_af_register(struct rtnl_af_ops *ops)

{

	list_add_tail(&ops->list, &rtnl_af_ops);

	return 0;

}

EXPORT_SYMBOL_GPL(__rtnl_af_register);



/**

 * rtnl_af_register - Register rtnl_af_ops with rtnetlink.

 * @ops: struct rtnl_af_ops * to register

 *

 * Returns 0 on success or a negative error code.

 */

int rtnl_af_register(struct rtnl_af_ops *ops)

{

	int err;



	rtnl_lock();

	err = __rtnl_af_register(ops);

	rtnl_unlock();

	return err;

}

EXPORT_SYMBOL_GPL(rtnl_af_register);



/**

 * __rtnl_af_unregister - Unregister rtnl_af_ops from rtnetlink.

 * @ops: struct rtnl_af_ops * to unregister

 *

 * The caller must hold the rtnl_mutex.

 */

void __rtnl_af_unregister(struct rtnl_af_ops *ops)

{

	list_del(&ops->list);

}

EXPORT_SYMBOL_GPL(__rtnl_af_unregister);



/**

 * rtnl_af_unregister - Unregister rtnl_af_ops from rtnetlink.

 * @ops: struct rtnl_af_ops * to unregister

 */

void rtnl_af_unregister(struct rtnl_af_ops *ops)

{

	rtnl_lock();

	__rtnl_af_unregister(ops);

	rtnl_unlock();

}

EXPORT_SYMBOL_GPL(rtnl_af_unregister);



static size_t rtnl_link_get_af_size(const struct net_device *dev)

{

	struct rtnl_af_ops *af_ops;

	size_t size;



	/* IFLA_AF_SPEC */

	size = nla_total_size(sizeof(struct nlattr));



	list_for_each_entry(af_ops, &rtnl_af_ops, list) {

		if (af_ops->get_link_af_size) {

			/* AF_* + nested data */

			size += nla_total_size(sizeof(struct nlattr)) +

				af_ops->get_link_af_size(dev);

		}

	}



	return size;

}



static int rtnl_link_fill(struct sk_buff *skb, const struct net_device *dev)

{

	const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
@@ -671,7 +760,8 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev) 
	       + nla_total_size(4) /* IFLA_NUM_VF */

	       + rtnl_vfinfo_size(dev) /* IFLA_VFINFO_LIST */

	       + rtnl_port_size(dev) /* IFLA_VF_PORTS + IFLA_PORT_SELF */

	       + rtnl_link_get_size(dev); /* IFLA_LINKINFO */

	       + rtnl_link_get_size(dev) /* IFLA_LINKINFO */

	       + rtnl_link_get_af_size(dev); /* IFLA_AF_SPEC */

}



static int rtnl_vf_ports_fill(struct sk_buff *skb, struct net_device *dev)
@@ -757,7 +847,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 
	struct nlmsghdr *nlh;

	struct rtnl_link_stats64 temp;

	const struct rtnl_link_stats64 *stats;

	struct nlattr *attr;

	struct nlattr *attr, *af_spec;

	struct rtnl_af_ops *af_ops;



	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags);

	if (nlh == NULL)
@@ -866,6 +957,36 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 
			goto nla_put_failure;

	}



	if (!(af_spec = nla_nest_start(skb, IFLA_AF_SPEC)))

		goto nla_put_failure;



	list_for_each_entry(af_ops, &rtnl_af_ops, list) {

		if (af_ops->fill_link_af) {

			struct nlattr *af;

			int err;



			if (!(af = nla_nest_start(skb, af_ops->family)))

				goto nla_put_failure;



			err = af_ops->fill_link_af(skb, dev);



			/*

			 * Caller may return ENODATA to indicate that there

			 * was no data to be dumped. This is not an error, it

			 * means we should trim the attribute header and

			 * continue.

			 */

			if (err == -ENODATA)

				nla_nest_cancel(skb, af);

			else if (err < 0)

				goto nla_put_failure;



			nla_nest_end(skb, af);

		}

	}



	nla_nest_end(skb, af_spec);



	return nlmsg_end(skb, nlh);



nla_put_failure:
@@ -924,6 +1045,7 @@ const struct nla_policy ifla_policy[IFLA_MAX+1] = { 
	[IFLA_VFINFO_LIST]	= {. type = NLA_NESTED },

	[IFLA_VF_PORTS]		= { .type = NLA_NESTED },

	[IFLA_PORT_SELF]	= { .type = NLA_NESTED },

	[IFLA_AF_SPEC]		= { .type = NLA_NESTED },

};

EXPORT_SYMBOL(ifla_policy);
@@ -1225,6 +1347,27 @@ static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm, 
			goto errout;

		modified = 1;

	}



	if (tb[IFLA_AF_SPEC]) {

		struct nlattr *af;

		int rem;



		nla_for_each_nested(af, tb[IFLA_AF_SPEC], rem) {

			const struct rtnl_af_ops *af_ops;



			if (!(af_ops = rtnl_af_lookup(nla_type(af))))

				continue;



			if (!af_ops->parse_link_af)

				continue;



			err = af_ops->parse_link_af(dev, af);

			if (err < 0)

				goto errout;



			modified = 1;

		}

	}

	err = 0;



errout:

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