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1#ifndef __NET_GENERIC_NETLINK_H
2#define __NET_GENERIC_NETLINK_H
3
4#include <linux/genetlink.h>
5#include <net/netlink.h>
6#include <net/net_namespace.h>
7
8#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
9
10/**
11 * struct genl_multicast_group - generic netlink multicast group
12 * @name: name of the multicast group, names are per-family
13 * @id: multicast group ID, assigned by the core, to use with
14 * genlmsg_multicast().
15 * @list: list entry for linking
16 * @family: pointer to family, need not be set before registering
17 */
18struct genl_multicast_group {
19 struct genl_family *family; /* private */
20 struct list_head list; /* private */
21 char name[GENL_NAMSIZ];
22 u32 id;
23};
24
25struct genl_ops;
26struct genl_info;
27
28/**
29 * struct genl_family - generic netlink family
30 * @id: protocol family idenfitier
31 * @hdrsize: length of user specific header in bytes
32 * @name: name of family
33 * @version: protocol version
34 * @maxattr: maximum number of attributes supported
35 * @netnsok: set to true if the family can handle network
36 * namespaces and should be presented in all of them
37 * @pre_doit: called before an operation's doit callback, it may
38 * do additional, common, filtering and return an error
39 * @post_doit: called after an operation's doit callback, it may
40 * undo operations done by pre_doit, for example release locks
41 * @attrbuf: buffer to store parsed attributes
42 * @ops_list: list of all assigned operations
43 * @family_list: family list
44 * @mcast_groups: multicast groups list
45 */
46struct genl_family {
47 unsigned int id;
48 unsigned int hdrsize;
49 char name[GENL_NAMSIZ];
50 unsigned int version;
51 unsigned int maxattr;
52 bool netnsok;
53 int (*pre_doit)(struct genl_ops *ops,
54 struct sk_buff *skb,
55 struct genl_info *info);
56 void (*post_doit)(struct genl_ops *ops,
57 struct sk_buff *skb,
58 struct genl_info *info);
59 struct nlattr ** attrbuf; /* private */
60 struct list_head ops_list; /* private */
61 struct list_head family_list; /* private */
62 struct list_head mcast_groups; /* private */
63};
64
65/**
66 * struct genl_info - receiving information
67 * @snd_seq: sending sequence number
68 * @snd_portid: netlink portid of sender
69 * @nlhdr: netlink message header
70 * @genlhdr: generic netlink message header
71 * @userhdr: user specific header
72 * @attrs: netlink attributes
73 * @_net: network namespace
74 * @user_ptr: user pointers
75 */
76struct genl_info {
77 u32 snd_seq;
78 u32 snd_portid;
79 struct nlmsghdr * nlhdr;
80 struct genlmsghdr * genlhdr;
81 void * userhdr;
82 struct nlattr ** attrs;
83#ifdef CONFIG_NET_NS
84 struct net * _net;
85#endif
86 void * user_ptr[2];
87};
88
89static inline struct net *genl_info_net(struct genl_info *info)
90{
91 return read_pnet(&info->_net);
92}
93
94static inline void genl_info_net_set(struct genl_info *info, struct net *net)
95{
96 write_pnet(&info->_net, net);
97}
98
99/**
100 * struct genl_ops - generic netlink operations
101 * @cmd: command identifier
102 * @internal_flags: flags used by the family
103 * @flags: flags
104 * @policy: attribute validation policy
105 * @doit: standard command callback
106 * @dumpit: callback for dumpers
107 * @done: completion callback for dumps
108 * @ops_list: operations list
109 */
110struct genl_ops {
111 u8 cmd;
112 u8 internal_flags;
113 unsigned int flags;
114 const struct nla_policy *policy;
115 int (*doit)(struct sk_buff *skb,
116 struct genl_info *info);
117 int (*dumpit)(struct sk_buff *skb,
118 struct netlink_callback *cb);
119 int (*done)(struct netlink_callback *cb);
120 struct list_head ops_list;
121};
122
123extern int genl_register_family(struct genl_family *family);
124extern int genl_register_family_with_ops(struct genl_family *family,
125 struct genl_ops *ops, size_t n_ops);
126extern int genl_unregister_family(struct genl_family *family);
127extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
128extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
129extern int genl_register_mc_group(struct genl_family *family,
130 struct genl_multicast_group *grp);
131extern void genl_unregister_mc_group(struct genl_family *family,
132 struct genl_multicast_group *grp);
133extern void genl_notify(struct sk_buff *skb, struct net *net, u32 portid,
134 u32 group, struct nlmsghdr *nlh, gfp_t flags);
135
136void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
137 struct genl_family *family, int flags, u8 cmd);
138
139/**
140 * genlmsg_nlhdr - Obtain netlink header from user specified header
141 * @user_hdr: user header as returned from genlmsg_put()
142 * @family: generic netlink family
143 *
144 * Returns pointer to netlink header.
145 */
146static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
147 struct genl_family *family)
148{
149 return (struct nlmsghdr *)((char *)user_hdr -
150 family->hdrsize -
151 GENL_HDRLEN -
152 NLMSG_HDRLEN);
153}
154
155/**
156 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
157 * @cb: netlink callback structure that stores the sequence number
158 * @user_hdr: user header as returned from genlmsg_put()
159 * @family: generic netlink family
160 *
161 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
162 * simpler to use with generic netlink.
163 */
164static inline void genl_dump_check_consistent(struct netlink_callback *cb,
165 void *user_hdr,
166 struct genl_family *family)
167{
168 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
169}
170
171/**
172 * genlmsg_put_reply - Add generic netlink header to a reply message
173 * @skb: socket buffer holding the message
174 * @info: receiver info
175 * @family: generic netlink family
176 * @flags: netlink message flags
177 * @cmd: generic netlink command
178 *
179 * Returns pointer to user specific header
180 */
181static inline void *genlmsg_put_reply(struct sk_buff *skb,
182 struct genl_info *info,
183 struct genl_family *family,
184 int flags, u8 cmd)
185{
186 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
187 flags, cmd);
188}
189
190/**
191 * genlmsg_end - Finalize a generic netlink message
192 * @skb: socket buffer the message is stored in
193 * @hdr: user specific header
194 */
195static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
196{
197 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
198}
199
200/**
201 * genlmsg_cancel - Cancel construction of a generic netlink message
202 * @skb: socket buffer the message is stored in
203 * @hdr: generic netlink message header
204 */
205static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
206{
207 if (hdr)
208 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
209}
210
211/**
212 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
213 * @net: the net namespace
214 * @skb: netlink message as socket buffer
215 * @portid: own netlink portid to avoid sending to yourself
216 * @group: multicast group id
217 * @flags: allocation flags
218 */
219static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
220 u32 portid, unsigned int group, gfp_t flags)
221{
222 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
223}
224
225/**
226 * genlmsg_multicast - multicast a netlink message to the default netns
227 * @skb: netlink message as socket buffer
228 * @portid: own netlink portid to avoid sending to yourself
229 * @group: multicast group id
230 * @flags: allocation flags
231 */
232static inline int genlmsg_multicast(struct sk_buff *skb, u32 portid,
233 unsigned int group, gfp_t flags)
234{
235 return genlmsg_multicast_netns(&init_net, skb, portid, group, flags);
236}
237
238/**
239 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
240 * @skb: netlink message as socket buffer
241 * @portid: own netlink portid to avoid sending to yourself
242 * @group: multicast group id
243 * @flags: allocation flags
244 *
245 * This function must hold the RTNL or rcu_read_lock().
246 */
247int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid,
248 unsigned int group, gfp_t flags);
249
250/**
251 * genlmsg_unicast - unicast a netlink message
252 * @skb: netlink message as socket buffer
253 * @portid: netlink portid of the destination socket
254 */
255static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
256{
257 return nlmsg_unicast(net->genl_sock, skb, portid);
258}
259
260/**
261 * genlmsg_reply - reply to a request
262 * @skb: netlink message to be sent back
263 * @info: receiver information
264 */
265static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
266{
267 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
268}
269
270/**
271 * gennlmsg_data - head of message payload
272 * @gnlh: genetlink message header
273 */
274static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
275{
276 return ((unsigned char *) gnlh + GENL_HDRLEN);
277}
278
279/**
280 * genlmsg_len - length of message payload
281 * @gnlh: genetlink message header
282 */
283static inline int genlmsg_len(const struct genlmsghdr *gnlh)
284{
285 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
286 NLMSG_HDRLEN);
287 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
288}
289
290/**
291 * genlmsg_msg_size - length of genetlink message not including padding
292 * @payload: length of message payload
293 */
294static inline int genlmsg_msg_size(int payload)
295{
296 return GENL_HDRLEN + payload;
297}
298
299/**
300 * genlmsg_total_size - length of genetlink message including padding
301 * @payload: length of message payload
302 */
303static inline int genlmsg_total_size(int payload)
304{
305 return NLMSG_ALIGN(genlmsg_msg_size(payload));
306}
307
308/**
309 * genlmsg_new - Allocate a new generic netlink message
310 * @payload: size of the message payload
311 * @flags: the type of memory to allocate.
312 */
313static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
314{
315 return nlmsg_new(genlmsg_total_size(payload), flags);
316}
317
318
319#endif /* __NET_GENERIC_NETLINK_H */