023e2cfa36
Netlink families can exist in multiple namespaces, and for the most part multicast subscriptions are per network namespace. Thus it only makes sense to have bind/unbind notifications per network namespace. To achieve this, pass the network namespace of a given client socket to the bind/unbind functions. Also do this in generic netlink, and there also make sure that any bind for multicast groups that only exist in init_net is rejected. This isn't really a problem if it is accepted since a client in a different namespace will never receive any notifications from such a group, but it can confuse the family if not rejected (it's also possible to silently (without telling the family) accept it, but it would also have to be ignored on unbind so families that take any kind of action on bind/unbind won't do unnecessary work for invalid clients like that. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
411 lines
12 KiB
C
411 lines
12 KiB
C
#ifndef __NET_GENERIC_NETLINK_H
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#define __NET_GENERIC_NETLINK_H
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#include <linux/genetlink.h>
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#include <net/netlink.h>
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#include <net/net_namespace.h>
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#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
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/**
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* struct genl_multicast_group - generic netlink multicast group
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* @name: name of the multicast group, names are per-family
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*/
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struct genl_multicast_group {
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char name[GENL_NAMSIZ];
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};
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struct genl_ops;
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struct genl_info;
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/**
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* struct genl_family - generic netlink family
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* @id: protocol family idenfitier
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* @hdrsize: length of user specific header in bytes
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* @name: name of family
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* @version: protocol version
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* @maxattr: maximum number of attributes supported
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* @netnsok: set to true if the family can handle network
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* namespaces and should be presented in all of them
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* @pre_doit: called before an operation's doit callback, it may
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* do additional, common, filtering and return an error
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* @post_doit: called after an operation's doit callback, it may
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* undo operations done by pre_doit, for example release locks
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* @mcast_bind: a socket bound to the given multicast group (which
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* is given as the offset into the groups array)
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* @mcast_unbind: a socket was unbound from the given multicast group
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* @attrbuf: buffer to store parsed attributes
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* @family_list: family list
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* @mcgrps: multicast groups used by this family (private)
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* @n_mcgrps: number of multicast groups (private)
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* @mcgrp_offset: starting number of multicast group IDs in this family
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* @ops: the operations supported by this family (private)
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* @n_ops: number of operations supported by this family (private)
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*/
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struct genl_family {
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unsigned int id;
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unsigned int hdrsize;
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char name[GENL_NAMSIZ];
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unsigned int version;
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unsigned int maxattr;
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bool netnsok;
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bool parallel_ops;
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int (*pre_doit)(const struct genl_ops *ops,
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struct sk_buff *skb,
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struct genl_info *info);
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void (*post_doit)(const struct genl_ops *ops,
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struct sk_buff *skb,
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struct genl_info *info);
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int (*mcast_bind)(struct net *net, int group);
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void (*mcast_unbind)(struct net *net, int group);
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struct nlattr ** attrbuf; /* private */
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const struct genl_ops * ops; /* private */
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const struct genl_multicast_group *mcgrps; /* private */
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unsigned int n_ops; /* private */
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unsigned int n_mcgrps; /* private */
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unsigned int mcgrp_offset; /* private */
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struct list_head family_list; /* private */
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struct module *module;
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};
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/**
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* struct genl_info - receiving information
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* @snd_seq: sending sequence number
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* @snd_portid: netlink portid of sender
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* @nlhdr: netlink message header
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* @genlhdr: generic netlink message header
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* @userhdr: user specific header
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* @attrs: netlink attributes
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* @_net: network namespace
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* @user_ptr: user pointers
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* @dst_sk: destination socket
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*/
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struct genl_info {
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u32 snd_seq;
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u32 snd_portid;
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struct nlmsghdr * nlhdr;
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struct genlmsghdr * genlhdr;
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void * userhdr;
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struct nlattr ** attrs;
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#ifdef CONFIG_NET_NS
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struct net * _net;
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#endif
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void * user_ptr[2];
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struct sock * dst_sk;
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};
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static inline struct net *genl_info_net(struct genl_info *info)
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{
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return read_pnet(&info->_net);
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}
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static inline void genl_info_net_set(struct genl_info *info, struct net *net)
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{
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write_pnet(&info->_net, net);
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}
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/**
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* struct genl_ops - generic netlink operations
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* @cmd: command identifier
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* @internal_flags: flags used by the family
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* @flags: flags
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* @policy: attribute validation policy
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* @doit: standard command callback
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* @dumpit: callback for dumpers
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* @done: completion callback for dumps
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* @ops_list: operations list
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*/
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struct genl_ops {
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const struct nla_policy *policy;
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int (*doit)(struct sk_buff *skb,
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struct genl_info *info);
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int (*dumpit)(struct sk_buff *skb,
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struct netlink_callback *cb);
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int (*done)(struct netlink_callback *cb);
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u8 cmd;
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u8 internal_flags;
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u8 flags;
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};
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int __genl_register_family(struct genl_family *family);
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static inline int genl_register_family(struct genl_family *family)
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{
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family->module = THIS_MODULE;
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return __genl_register_family(family);
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}
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/**
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* genl_register_family_with_ops - register a generic netlink family with ops
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* @family: generic netlink family
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* @ops: operations to be registered
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* @n_ops: number of elements to register
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*
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* Registers the specified family and operations from the specified table.
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* Only one family may be registered with the same family name or identifier.
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*
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* The family id may equal GENL_ID_GENERATE causing an unique id to
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* be automatically generated and assigned.
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*
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* Either a doit or dumpit callback must be specified for every registered
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* operation or the function will fail. Only one operation structure per
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* command identifier may be registered.
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*
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* See include/net/genetlink.h for more documenation on the operations
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* structure.
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*
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* Return 0 on success or a negative error code.
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*/
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static inline int
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_genl_register_family_with_ops_grps(struct genl_family *family,
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const struct genl_ops *ops, size_t n_ops,
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const struct genl_multicast_group *mcgrps,
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size_t n_mcgrps)
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{
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family->module = THIS_MODULE;
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family->ops = ops;
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family->n_ops = n_ops;
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family->mcgrps = mcgrps;
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family->n_mcgrps = n_mcgrps;
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return __genl_register_family(family);
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}
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#define genl_register_family_with_ops(family, ops) \
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_genl_register_family_with_ops_grps((family), \
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(ops), ARRAY_SIZE(ops), \
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NULL, 0)
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#define genl_register_family_with_ops_groups(family, ops, grps) \
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_genl_register_family_with_ops_grps((family), \
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(ops), ARRAY_SIZE(ops), \
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(grps), ARRAY_SIZE(grps))
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int genl_unregister_family(struct genl_family *family);
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void genl_notify(struct genl_family *family,
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struct sk_buff *skb, struct net *net, u32 portid,
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u32 group, struct nlmsghdr *nlh, gfp_t flags);
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struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
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gfp_t flags);
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void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
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struct genl_family *family, int flags, u8 cmd);
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/**
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* genlmsg_nlhdr - Obtain netlink header from user specified header
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* @user_hdr: user header as returned from genlmsg_put()
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* @family: generic netlink family
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*
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* Returns pointer to netlink header.
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*/
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static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
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struct genl_family *family)
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{
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return (struct nlmsghdr *)((char *)user_hdr -
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family->hdrsize -
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GENL_HDRLEN -
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NLMSG_HDRLEN);
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}
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/**
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* genl_dump_check_consistent - check if sequence is consistent and advertise if not
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* @cb: netlink callback structure that stores the sequence number
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* @user_hdr: user header as returned from genlmsg_put()
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* @family: generic netlink family
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*
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* Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
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* simpler to use with generic netlink.
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*/
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static inline void genl_dump_check_consistent(struct netlink_callback *cb,
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void *user_hdr,
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struct genl_family *family)
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{
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nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
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}
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/**
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* genlmsg_put_reply - Add generic netlink header to a reply message
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* @skb: socket buffer holding the message
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* @info: receiver info
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* @family: generic netlink family
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* @flags: netlink message flags
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* @cmd: generic netlink command
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*
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* Returns pointer to user specific header
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*/
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static inline void *genlmsg_put_reply(struct sk_buff *skb,
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struct genl_info *info,
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struct genl_family *family,
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int flags, u8 cmd)
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{
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return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
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flags, cmd);
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}
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/**
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* genlmsg_end - Finalize a generic netlink message
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* @skb: socket buffer the message is stored in
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* @hdr: user specific header
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*/
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static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
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{
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return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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}
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/**
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* genlmsg_cancel - Cancel construction of a generic netlink message
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* @skb: socket buffer the message is stored in
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* @hdr: generic netlink message header
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*/
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static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
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{
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if (hdr)
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nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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}
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/**
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* genlmsg_multicast_netns - multicast a netlink message to a specific netns
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* @family: the generic netlink family
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* @net: the net namespace
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* @skb: netlink message as socket buffer
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* @portid: own netlink portid to avoid sending to yourself
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* @group: offset of multicast group in groups array
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* @flags: allocation flags
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*/
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static inline int genlmsg_multicast_netns(struct genl_family *family,
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struct net *net, struct sk_buff *skb,
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u32 portid, unsigned int group, gfp_t flags)
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{
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if (WARN_ON_ONCE(group >= family->n_mcgrps))
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return -EINVAL;
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group = family->mcgrp_offset + group;
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return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
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}
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/**
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* genlmsg_multicast - multicast a netlink message to the default netns
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* @family: the generic netlink family
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* @skb: netlink message as socket buffer
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* @portid: own netlink portid to avoid sending to yourself
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* @group: offset of multicast group in groups array
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* @flags: allocation flags
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*/
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static inline int genlmsg_multicast(struct genl_family *family,
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struct sk_buff *skb, u32 portid,
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unsigned int group, gfp_t flags)
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{
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return genlmsg_multicast_netns(family, &init_net, skb,
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portid, group, flags);
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}
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/**
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* genlmsg_multicast_allns - multicast a netlink message to all net namespaces
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* @family: the generic netlink family
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* @skb: netlink message as socket buffer
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* @portid: own netlink portid to avoid sending to yourself
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* @group: offset of multicast group in groups array
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* @flags: allocation flags
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*
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* This function must hold the RTNL or rcu_read_lock().
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*/
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int genlmsg_multicast_allns(struct genl_family *family,
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struct sk_buff *skb, u32 portid,
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unsigned int group, gfp_t flags);
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/**
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* genlmsg_unicast - unicast a netlink message
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* @skb: netlink message as socket buffer
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* @portid: netlink portid of the destination socket
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*/
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static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
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{
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return nlmsg_unicast(net->genl_sock, skb, portid);
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}
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/**
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* genlmsg_reply - reply to a request
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* @skb: netlink message to be sent back
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* @info: receiver information
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*/
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static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
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{
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return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
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}
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/**
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* gennlmsg_data - head of message payload
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* @gnlh: genetlink message header
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*/
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static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
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{
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return ((unsigned char *) gnlh + GENL_HDRLEN);
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}
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/**
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* genlmsg_len - length of message payload
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* @gnlh: genetlink message header
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*/
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static inline int genlmsg_len(const struct genlmsghdr *gnlh)
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{
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struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
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NLMSG_HDRLEN);
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return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
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}
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/**
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* genlmsg_msg_size - length of genetlink message not including padding
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* @payload: length of message payload
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*/
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static inline int genlmsg_msg_size(int payload)
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{
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return GENL_HDRLEN + payload;
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}
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/**
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* genlmsg_total_size - length of genetlink message including padding
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* @payload: length of message payload
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*/
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static inline int genlmsg_total_size(int payload)
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{
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return NLMSG_ALIGN(genlmsg_msg_size(payload));
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}
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/**
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* genlmsg_new - Allocate a new generic netlink message
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* @payload: size of the message payload
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* @flags: the type of memory to allocate.
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*/
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static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
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{
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return nlmsg_new(genlmsg_total_size(payload), flags);
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}
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/**
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* genl_set_err - report error to genetlink broadcast listeners
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* @family: the generic netlink family
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* @net: the network namespace to report the error to
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* @portid: the PORTID of a process that we want to skip (if any)
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* @group: the broadcast group that will notice the error
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* (this is the offset of the multicast group in the groups array)
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* @code: error code, must be negative (as usual in kernelspace)
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*
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* This function returns the number of broadcast listeners that have set the
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* NETLINK_RECV_NO_ENOBUFS socket option.
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*/
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static inline int genl_set_err(struct genl_family *family, struct net *net,
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u32 portid, u32 group, int code)
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{
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if (WARN_ON_ONCE(group >= family->n_mcgrps))
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return -EINVAL;
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group = family->mcgrp_offset + group;
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return netlink_set_err(net->genl_sock, portid, group, code);
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}
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static inline int genl_has_listeners(struct genl_family *family,
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struct net *net, unsigned int group)
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{
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if (WARN_ON_ONCE(group >= family->n_mcgrps))
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return -EINVAL;
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group = family->mcgrp_offset + group;
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return netlink_has_listeners(net->genl_sock, group);
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}
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#endif /* __NET_GENERIC_NETLINK_H */
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