- 根目录:
- include
- net
- genetlink.h
#ifndef __NET_GENERIC_NETLINK_H
#define __NET_GENERIC_NETLINK_H
#include <linux/genetlink.h>
#include <net/netlink.h>
#include <net/net_namespace.h>
#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
/**
* struct genl_multicast_group - generic netlink multicast group
* @name: name of the multicast group, names are per-family
*/
struct genl_multicast_group {
char name[GENL_NAMSIZ];
};
struct genl_ops;
struct genl_info;
/**
* struct genl_family - generic netlink family
* @id: protocol family idenfitier
* @hdrsize: length of user specific header in bytes
* @name: name of family
* @version: protocol version
* @maxattr: maximum number of attributes supported
* @netnsok: set to true if the family can handle network
* namespaces and should be presented in all of them
* @parallel_ops: operations can be called in parallel and aren't
* synchronized by the core genetlink code
* @pre_doit: called before an operation's doit callback, it may
* do additional, common, filtering and return an error
* @post_doit: called after an operation's doit callback, it may
* undo operations done by pre_doit, for example release locks
* @mcast_bind: a socket bound to the given multicast group (which
* is given as the offset into the groups array)
* @mcast_unbind: a socket was unbound from the given multicast group.
* Note that unbind() will not be called symmetrically if the
* generic netlink family is removed while there are still open
* sockets.
* @attrbuf: buffer to store parsed attributes
* @family_list: family list
* @mcgrps: multicast groups used by this family (private)
* @n_mcgrps: number of multicast groups (private)
* @mcgrp_offset: starting number of multicast group IDs in this family
* @ops: the operations supported by this family (private)
* @n_ops: number of operations supported by this family (private)
*/
struct genl_family {
unsigned int id;
unsigned int hdrsize;
char name[GENL_NAMSIZ];
unsigned int version;
unsigned int maxattr;
bool netnsok;
bool parallel_ops;
int (*pre_doit)(const struct genl_ops *ops,
struct sk_buff *skb,
struct genl_info *info);
void (*post_doit)(const struct genl_ops *ops,
struct sk_buff *skb,
struct genl_info *info);
int (*mcast_bind)(struct net *net, int group);
void (*mcast_unbind)(struct net *net, int group);
struct nlattr ** attrbuf; /* private */
const struct genl_ops * ops; /* private */
const struct genl_multicast_group *mcgrps; /* private */
unsigned int n_ops; /* private */
unsigned int n_mcgrps; /* private */
unsigned int mcgrp_offset; /* private */
struct list_head family_list; /* private */
struct module *module;
};
/**
* struct genl_info - receiving information
* @snd_seq: sending sequence number
* @snd_portid: netlink portid of sender
* @nlhdr: netlink message header
* @genlhdr: generic netlink message header
* @userhdr: user specific header
* @attrs: netlink attributes
* @_net: network namespace
* @user_ptr: user pointers
* @dst_sk: destination socket
*/
struct genl_info {
u32 snd_seq;
u32 snd_portid;
struct nlmsghdr * nlhdr;
struct genlmsghdr * genlhdr;
void * userhdr;
struct nlattr ** attrs;
possible_net_t _net;
void * user_ptr[2];
struct sock * dst_sk;
};
static inline struct net *genl_info_net(struct genl_info *info)
{
return read_pnet(&info->_net);
}
static inline void genl_info_net_set(struct genl_info *info, struct net *net)
{
write_pnet(&info->_net, net);
}
/**
* struct genl_ops - generic netlink operations
* @cmd: command identifier
* @internal_flags: flags used by the family
* @flags: flags
* @policy: attribute validation policy
* @doit: standard command callback
* @dumpit: callback for dumpers
* @done: completion callback for dumps
* @ops_list: operations list
*/
struct genl_ops {
const struct nla_policy *policy;
int (*doit)(struct sk_buff *skb,
struct genl_info *info);
int (*dumpit)(struct sk_buff *skb,
struct netlink_callback *cb);
int (*done)(struct netlink_callback *cb);
u8 cmd;
u8 internal_flags;
u8 flags;
};
int __genl_register_family(struct genl_family *family);
static inline int genl_register_family(struct genl_family *family)
{
family->module = THIS_MODULE;
return __genl_register_family(family);
}
/**
* genl_register_family_with_ops - register a generic netlink family with ops
* @family: generic netlink family
* @ops: operations to be registered
* @n_ops: number of elements to register
*
* Registers the specified family and operations from the specified table.
* Only one family may be registered with the same family name or identifier.
*
* The family id may equal GENL_ID_GENERATE causing an unique id to
* be automatically generated and assigned.
*
* Either a doit or dumpit callback must be specified for every registered
* operation or the function will fail. Only one operation structure per
* command identifier may be registered.
*
* See include/net/genetlink.h for more documenation on the operations
* structure.
*
* Return 0 on success or a negative error code.
*/
static inline int
_genl_register_family_with_ops_grps(struct genl_family *family,
const struct genl_ops *ops, size_t n_ops,
const struct genl_multicast_group *mcgrps,
size_t n_mcgrps)
{
family->module = THIS_MODULE;
family->ops = ops;
family->n_ops = n_ops;
family->mcgrps = mcgrps;
family->n_mcgrps = n_mcgrps;
return __genl_register_family(family);
}
#define genl_register_family_with_ops(family, ops) \
_genl_register_family_with_ops_grps((family), \
(ops), ARRAY_SIZE(ops), \
NULL, 0)
#define genl_register_family_with_ops_groups(family, ops, grps) \
_genl_register_family_with_ops_grps((family), \
(ops), ARRAY_SIZE(ops), \
(grps), ARRAY_SIZE(grps))
int genl_unregister_family(struct genl_family *family);
void genl_notify(struct genl_family *family, struct sk_buff *skb,
struct genl_info *info, u32 group, gfp_t flags);
struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
gfp_t flags);
void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
struct genl_family *family, int flags, u8 cmd);
/**
* genlmsg_nlhdr - Obtain netlink header from user specified header
* @user_hdr: user header as returned from genlmsg_put()
* @family: generic netlink family
*
* Returns pointer to netlink header.
*/
static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
struct genl_family *family)
{
return (struct nlmsghdr *)((char *)user_hdr -
family->hdrsize -
GENL_HDRLEN -
NLMSG_HDRLEN);
}
/**
* genlmsg_parse - parse attributes of a genetlink message
* @nlh: netlink message header
* @family: genetlink message family
* @tb: destination array with maxtype+1 elements
* @maxtype: maximum attribute type to be expected
* @policy: validation policy
* */
static inline int genlmsg_parse(const struct nlmsghdr *nlh,
const struct genl_family *family,
struct nlattr *tb[], int maxtype,
const struct nla_policy *policy)
{
return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
policy);
}
/**
* genl_dump_check_consistent - check if sequence is consistent and advertise if not
* @cb: netlink callback structure that stores the sequence number
* @user_hdr: user header as returned from genlmsg_put()
* @family: generic netlink family
*
* Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
* simpler to use with generic netlink.
*/
static inline void genl_dump_check_consistent(struct netlink_callback *cb,
void *user_hdr,
struct genl_family *family)
{
nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
}
/**
* genlmsg_put_reply - Add generic netlink header to a reply message
* @skb: socket buffer holding the message
* @info: receiver info
* @family: generic netlink family
* @flags: netlink message flags
* @cmd: generic netlink command
*
* Returns pointer to user specific header
*/
static inline void *genlmsg_put_reply(struct sk_buff *skb,
struct genl_info *info,
struct genl_family *family,
int flags, u8 cmd)
{
return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
flags, cmd);
}
/**
* genlmsg_end - Finalize a generic netlink message
* @skb: socket buffer the message is stored in
* @hdr: user specific header
*/
static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
{
nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
}
/**
* genlmsg_cancel - Cancel construction of a generic netlink message
* @skb: socket buffer the message is stored in
* @hdr: generic netlink message header
*/
static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
{
if (hdr)
nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
}
/**
* genlmsg_multicast_netns - multicast a netlink message to a specific netns
* @family: the generic netlink family
* @net: the net namespace
* @skb: netlink message as socket buffer
* @portid: own netlink portid to avoid sending to yourself
* @group: offset of multicast group in groups array
* @flags: allocation flags
*/
static inline int genlmsg_multicast_netns(struct genl_family *family,
struct net *net, struct sk_buff *skb,
u32 portid, unsigned int group, gfp_t flags)
{
if (WARN_ON_ONCE(group >= family->n_mcgrps))
return -EINVAL;
group = family->mcgrp_offset + group;
return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
}
/**
* genlmsg_multicast - multicast a netlink message to the default netns
* @family: the generic netlink family
* @skb: netlink message as socket buffer
* @portid: own netlink portid to avoid sending to yourself
* @group: offset of multicast group in groups array
* @flags: allocation flags
*/
static inline int genlmsg_multicast(struct genl_family *family,
struct sk_buff *skb, u32 portid,
unsigned int group, gfp_t flags)
{
return genlmsg_multicast_netns(family, &init_net, skb,
portid, group, flags);
}
/**
* genlmsg_multicast_allns - multicast a netlink message to all net namespaces
* @family: the generic netlink family
* @skb: netlink message as socket buffer
* @portid: own netlink portid to avoid sending to yourself
* @group: offset of multicast group in groups array
* @flags: allocation flags
*
* This function must hold the RTNL or rcu_read_lock().
*/
int genlmsg_multicast_allns(struct genl_family *family,
struct sk_buff *skb, u32 portid,
unsigned int group, gfp_t flags);
/**
* genlmsg_unicast - unicast a netlink message
* @skb: netlink message as socket buffer
* @portid: netlink portid of the destination socket
*/
static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
{
return nlmsg_unicast(net->genl_sock, skb, portid);
}
/**
* genlmsg_reply - reply to a request
* @skb: netlink message to be sent back
* @info: receiver information
*/
static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
{
return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
}
/**
* gennlmsg_data - head of message payload
* @gnlh: genetlink message header
*/
static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
{
return ((unsigned char *) gnlh + GENL_HDRLEN);
}
/**
* genlmsg_len - length of message payload
* @gnlh: genetlink message header
*/
static inline int genlmsg_len(const struct genlmsghdr *gnlh)
{
struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
NLMSG_HDRLEN);
return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
}
/**
* genlmsg_msg_size - length of genetlink message not including padding
* @payload: length of message payload
*/
static inline int genlmsg_msg_size(int payload)
{
return GENL_HDRLEN + payload;
}
/**
* genlmsg_total_size - length of genetlink message including padding
* @payload: length of message payload
*/
static inline int genlmsg_total_size(int payload)
{
return NLMSG_ALIGN(genlmsg_msg_size(payload));
}
/**
* genlmsg_new - Allocate a new generic netlink message
* @payload: size of the message payload
* @flags: the type of memory to allocate.
*/
static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
{
return nlmsg_new(genlmsg_total_size(payload), flags);
}
/**
* genl_set_err - report error to genetlink broadcast listeners
* @family: the generic netlink family
* @net: the network namespace to report the error to
* @portid: the PORTID of a process that we want to skip (if any)
* @group: the broadcast group that will notice the error
* (this is the offset of the multicast group in the groups array)
* @code: error code, must be negative (as usual in kernelspace)
*
* This function returns the number of broadcast listeners that have set the
* NETLINK_RECV_NO_ENOBUFS socket option.
*/
static inline int genl_set_err(struct genl_family *family, struct net *net,
u32 portid, u32 group, int code)
{
if (WARN_ON_ONCE(group >= family->n_mcgrps))
return -EINVAL;
group = family->mcgrp_offset + group;
return netlink_set_err(net->genl_sock, portid, group, code);
}
static inline int genl_has_listeners(struct genl_family *family,
struct net *net, unsigned int group)
{
if (WARN_ON_ONCE(group >= family->n_mcgrps))
return -EINVAL;
group = family->mcgrp_offset + group;
return netlink_has_listeners(net->genl_sock, group);
}
#endif /* __NET_GENERIC_NETLINK_H */