linux/include/net/rtnetlink.h
Thomas Graf cf7afbfeb8 rtnl: make link af-specific updates atomic
As David pointed out correctly, updates to af-specific attributes
are currently not atomic. If multiple changes are requested and
one of them fails, previous updates may have been applied already
leaving the link behind in a undefined state.

This patch splits the function parse_link_af() into two functions
validate_link_af() and set_link_at(). validate_link_af() is placed
to validate_linkmsg() check for errors as early as possible before
any changes to the link have been made. set_link_af() is called to
commit the changes later.

This method is not fail proof, while it is currently sufficient
to make set_link_af() inerrable and thus 100% atomic, the
validation function method will not be able to detect all error
scenarios in the future, there will likely always be errors
depending on states which are f.e. not protected by rtnl_mutex
and thus may change between validation and setting.

Also, instead of silently ignoring unknown address families and
config blocks for address families which did not register a set
function the errors EAFNOSUPPORT respectively EOPNOSUPPORT are
returned to avoid comitting 4 out of 5 update requests without
notifying the user.

Signed-off-by: Thomas Graf <tgraf@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-27 22:56:08 -08:00

131 lines
4.5 KiB
C

#ifndef __NET_RTNETLINK_H
#define __NET_RTNETLINK_H
#include <linux/rtnetlink.h>
#include <net/netlink.h>
typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *, void *);
typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *);
extern int __rtnl_register(int protocol, int msgtype,
rtnl_doit_func, rtnl_dumpit_func);
extern void rtnl_register(int protocol, int msgtype,
rtnl_doit_func, rtnl_dumpit_func);
extern int rtnl_unregister(int protocol, int msgtype);
extern void rtnl_unregister_all(int protocol);
static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
{
if (nlmsg_len(nlh) >= sizeof(struct rtgenmsg))
return ((struct rtgenmsg *) nlmsg_data(nlh))->rtgen_family;
else
return AF_UNSPEC;
}
/**
* struct rtnl_link_ops - rtnetlink link operations
*
* @list: Used internally
* @kind: Identifier
* @maxtype: Highest device specific netlink attribute number
* @policy: Netlink policy for device specific attribute validation
* @validate: Optional validation function for netlink/changelink parameters
* @priv_size: sizeof net_device private space
* @setup: net_device setup function
* @newlink: Function for configuring and registering a new device
* @changelink: Function for changing parameters of an existing device
* @dellink: Function to remove a device
* @get_size: Function to calculate required room for dumping device
* specific netlink attributes
* @fill_info: Function to dump device specific netlink attributes
* @get_xstats_size: Function to calculate required room for dumping devic
* specific statistics
* @fill_xstats: Function to dump device specific statistics
*/
struct rtnl_link_ops {
struct list_head list;
const char *kind;
size_t priv_size;
void (*setup)(struct net_device *dev);
int maxtype;
const struct nla_policy *policy;
int (*validate)(struct nlattr *tb[],
struct nlattr *data[]);
int (*newlink)(struct net *src_net,
struct net_device *dev,
struct nlattr *tb[],
struct nlattr *data[]);
int (*changelink)(struct net_device *dev,
struct nlattr *tb[],
struct nlattr *data[]);
void (*dellink)(struct net_device *dev,
struct list_head *head);
size_t (*get_size)(const struct net_device *dev);
int (*fill_info)(struct sk_buff *skb,
const struct net_device *dev);
size_t (*get_xstats_size)(const struct net_device *dev);
int (*fill_xstats)(struct sk_buff *skb,
const struct net_device *dev);
int (*get_tx_queues)(struct net *net, struct nlattr *tb[],
unsigned int *tx_queues,
unsigned int *real_tx_queues);
};
extern int __rtnl_link_register(struct rtnl_link_ops *ops);
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.
* @validate_link_af: Validate a IFLA_AF_SPEC attribute, must check attr
* for invalid configuration settings.
* @set_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 (*validate_link_af)(const struct net_device *dev,
const struct nlattr *attr);
int (*set_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[]);
extern int rtnl_configure_link(struct net_device *dev,
const struct ifinfomsg *ifm);
extern const struct nla_policy ifla_policy[IFLA_MAX+1];
#define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind)
#endif