388 lines
12 KiB
C
388 lines
12 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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 identifier (private)
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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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* @parallel_ops: operations can be called in parallel and aren't
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* synchronized by the core genetlink code
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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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* Note that unbind() will not be called symmetrically if the
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* generic netlink family is removed while there are still open
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* sockets.
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* @attrbuf: buffer to store parsed attributes (private)
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* @mcgrps: multicast groups used by this family
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* @n_mcgrps: number of multicast groups
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* @mcgrp_offset: starting number of multicast group IDs in this family
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* (private)
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* @ops: the operations supported by this family
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* @n_ops: number of operations supported by this family
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*/
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struct genl_family {
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int id; /* private */
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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;
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const struct genl_multicast_group *mcgrps;
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unsigned int n_ops;
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unsigned int n_mcgrps;
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unsigned int mcgrp_offset; /* private */
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struct module *module;
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};
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struct nlattr **genl_family_attrbuf(const struct genl_family *family);
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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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* @extack: extended ACK report struct
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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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possible_net_t _net;
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void * user_ptr[2];
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struct netlink_ext_ack *extack;
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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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#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
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static inline int genl_err_attr(struct genl_info *info, int err,
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struct nlattr *attr)
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{
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info->extack->bad_attr = attr;
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return err;
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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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* @start: start callback for dumps
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* @dumpit: callback for dumpers
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* @done: completion callback for dumps
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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 (*start)(struct netlink_callback *cb);
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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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int genl_unregister_family(const struct genl_family *family);
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void genl_notify(const struct genl_family *family, struct sk_buff *skb,
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struct genl_info *info, u32 group, gfp_t flags);
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void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
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const 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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*
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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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{
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return (struct nlmsghdr *)((char *)user_hdr -
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GENL_HDRLEN -
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NLMSG_HDRLEN);
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}
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/**
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* genlmsg_parse - parse attributes of a genetlink message
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* @nlh: netlink message header
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* @family: genetlink message family
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* @tb: destination array with maxtype+1 elements
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* @maxtype: maximum attribute type to be expected
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* @policy: validation policy
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* @extack: extended ACK report struct
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*/
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static inline int genlmsg_parse(const struct nlmsghdr *nlh,
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const struct genl_family *family,
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struct nlattr *tb[], int maxtype,
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const struct nla_policy *policy,
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struct netlink_ext_ack *extack)
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{
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return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
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policy, extack);
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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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*
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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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{
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nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
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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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const 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 void genlmsg_end(struct sk_buff *skb, void *hdr)
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{
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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(const 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(const 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(const 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(const struct genl_family *family,
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struct net *net, u32 portid,
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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(const 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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