genetlink.h 9.7 KB

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