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linux/include/net/rtnetlink.h
Greg Rose 115c9b8192 rtnetlink: Fix problem with buffer allocation 
Implement a new netlink attribute type IFLA_EXT_MASK.  The mask
is a 32 bit value that can be used to indicate to the kernel that
certain extended ifinfo values are requested by the user application.
At this time the only mask value defined is RTEXT_FILTER_VF to
indicate that the user wants the ifinfo dump to send information
about the VFs belonging to the interface.

This patch fixes a bug in which certain applications do not have
large enough buffers to accommodate the extra information returned
by the kernel with large numbers of SR-IOV virtual functions.
Those applications will not send the new netlink attribute with
the interface info dump request netlink messages so they will
not get unexpectedly large request buffers returned by the kernel.

Modifies the rtnl_calcit function to traverse the list of net
devices and compute the minimum buffer size that can hold the
info dumps of all matching devices based upon the filter passed
in via the new netlink attribute filter mask.  If no filter
mask is sent then the buffer allocation defaults to NLMSG_GOODSIZE.

With this change it is possible to add yet to be defined netlink
attributes to the dump request which should make it fairly extensible
in the future.

Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-02-21 16:56:45 -05:00

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#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 *);
typedef u16 (*rtnl_calcit_func)(struct sk_buff *, struct nlmsghdr *);
extern int __rtnl_register(int protocol, int msgtype,
rtnl_doit_func, rtnl_dumpit_func,
rtnl_calcit_func);
extern void rtnl_register(int protocol, int msgtype,
rtnl_doit_func, rtnl_dumpit_func,
rtnl_calcit_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
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