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