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 */ 14 struct genl_multicast_group { 15 char name[GENL_NAMSIZ]; 16 }; 17 18 struct genl_ops; 19 struct genl_info; 20 21 /** 22 * struct genl_family - generic netlink family 23 * @id: protocol family idenfitier 24 * @hdrsize: length of user specific header in bytes 25 * @name: name of family 26 * @version: protocol version 27 * @maxattr: maximum number of attributes supported 28 * @netnsok: set to true if the family can handle network 29 * namespaces and should be presented in all of them 30 * @parallel_ops: operations can be called in parallel and aren't 31 * synchronized by the core genetlink code 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 * @mcast_bind: a socket bound to the given multicast group (which 37 * is given as the offset into the groups array) 38 * @mcast_unbind: a socket was unbound from the given multicast group. 39 * Note that unbind() will not be called symmetrically if the 40 * generic netlink family is removed while there are still open 41 * sockets. 42 * @attrbuf: buffer to store parsed attributes 43 * @family_list: family list 44 * @mcgrps: multicast groups used by this family (private) 45 * @n_mcgrps: number of multicast groups (private) 46 * @mcgrp_offset: starting number of multicast group IDs in this family 47 * @ops: the operations supported by this family (private) 48 * @n_ops: number of operations supported by this family (private) 49 */ 50 struct genl_family { 51 unsigned int id; 52 unsigned int hdrsize; 53 char name[GENL_NAMSIZ]; 54 unsigned int version; 55 unsigned int maxattr; 56 bool netnsok; 57 bool parallel_ops; 58 int (*pre_doit)(const struct genl_ops *ops, 59 struct sk_buff *skb, 60 struct genl_info *info); 61 void (*post_doit)(const struct genl_ops *ops, 62 struct sk_buff *skb, 63 struct genl_info *info); 64 int (*mcast_bind)(struct net *net, int group); 65 void (*mcast_unbind)(struct net *net, int group); 66 struct nlattr ** attrbuf; /* private */ 67 const struct genl_ops * ops; /* private */ 68 const struct genl_multicast_group *mcgrps; /* private */ 69 unsigned int n_ops; /* private */ 70 unsigned int n_mcgrps; /* private */ 71 unsigned int mcgrp_offset; /* private */ 72 struct list_head family_list; /* private */ 73 struct module *module; 74 }; 75 76 /** 77 * struct genl_info - receiving information 78 * @snd_seq: sending sequence number 79 * @snd_portid: netlink portid of sender 80 * @nlhdr: netlink message header 81 * @genlhdr: generic netlink message header 82 * @userhdr: user specific header 83 * @attrs: netlink attributes 84 * @_net: network namespace 85 * @user_ptr: user pointers 86 * @dst_sk: destination socket 87 */ 88 struct genl_info { 89 u32 snd_seq; 90 u32 snd_portid; 91 struct nlmsghdr * nlhdr; 92 struct genlmsghdr * genlhdr; 93 void * userhdr; 94 struct nlattr ** attrs; 95 #ifdef CONFIG_NET_NS 96 struct net * _net; 97 #endif 98 void * user_ptr[2]; 99 struct sock * dst_sk; 100 }; 101 102 static inline struct net *genl_info_net(struct genl_info *info) 103 { 104 return read_pnet(&info->_net); 105 } 106 107 static inline void genl_info_net_set(struct genl_info *info, struct net *net) 108 { 109 write_pnet(&info->_net, net); 110 } 111 112 /** 113 * struct genl_ops - generic netlink operations 114 * @cmd: command identifier 115 * @internal_flags: flags used by the family 116 * @flags: flags 117 * @policy: attribute validation policy 118 * @doit: standard command callback 119 * @dumpit: callback for dumpers 120 * @done: completion callback for dumps 121 * @ops_list: operations list 122 */ 123 struct genl_ops { 124 const struct nla_policy *policy; 125 int (*doit)(struct sk_buff *skb, 126 struct genl_info *info); 127 int (*dumpit)(struct sk_buff *skb, 128 struct netlink_callback *cb); 129 int (*done)(struct netlink_callback *cb); 130 u8 cmd; 131 u8 internal_flags; 132 u8 flags; 133 }; 134 135 int __genl_register_family(struct genl_family *family); 136 137 static inline int genl_register_family(struct genl_family *family) 138 { 139 family->module = THIS_MODULE; 140 return __genl_register_family(family); 141 } 142 143 /** 144 * genl_register_family_with_ops - register a generic netlink family with ops 145 * @family: generic netlink family 146 * @ops: operations to be registered 147 * @n_ops: number of elements to register 148 * 149 * Registers the specified family and operations from the specified table. 150 * Only one family may be registered with the same family name or identifier. 151 * 152 * The family id may equal GENL_ID_GENERATE causing an unique id to 153 * be automatically generated and assigned. 154 * 155 * Either a doit or dumpit callback must be specified for every registered 156 * operation or the function will fail. Only one operation structure per 157 * command identifier may be registered. 158 * 159 * See include/net/genetlink.h for more documenation on the operations 160 * structure. 161 * 162 * Return 0 on success or a negative error code. 163 */ 164 static inline int 165 _genl_register_family_with_ops_grps(struct genl_family *family, 166 const struct genl_ops *ops, size_t n_ops, 167 const struct genl_multicast_group *mcgrps, 168 size_t n_mcgrps) 169 { 170 family->module = THIS_MODULE; 171 family->ops = ops; 172 family->n_ops = n_ops; 173 family->mcgrps = mcgrps; 174 family->n_mcgrps = n_mcgrps; 175 return __genl_register_family(family); 176 } 177 178 #define genl_register_family_with_ops(family, ops) \ 179 _genl_register_family_with_ops_grps((family), \ 180 (ops), ARRAY_SIZE(ops), \ 181 NULL, 0) 182 #define genl_register_family_with_ops_groups(family, ops, grps) \ 183 _genl_register_family_with_ops_grps((family), \ 184 (ops), ARRAY_SIZE(ops), \ 185 (grps), ARRAY_SIZE(grps)) 186 187 int genl_unregister_family(struct genl_family *family); 188 void genl_notify(struct genl_family *family, 189 struct sk_buff *skb, struct net *net, u32 portid, 190 u32 group, struct nlmsghdr *nlh, gfp_t flags); 191 192 struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, 193 gfp_t flags); 194 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 195 struct genl_family *family, int flags, u8 cmd); 196 197 /** 198 * genlmsg_nlhdr - Obtain netlink header from user specified header 199 * @user_hdr: user header as returned from genlmsg_put() 200 * @family: generic netlink family 201 * 202 * Returns pointer to netlink header. 203 */ 204 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr, 205 struct genl_family *family) 206 { 207 return (struct nlmsghdr *)((char *)user_hdr - 208 family->hdrsize - 209 GENL_HDRLEN - 210 NLMSG_HDRLEN); 211 } 212 213 /** 214 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 215 * @cb: netlink callback structure that stores the sequence number 216 * @user_hdr: user header as returned from genlmsg_put() 217 * @family: generic netlink family 218 * 219 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 220 * simpler to use with generic netlink. 221 */ 222 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 223 void *user_hdr, 224 struct genl_family *family) 225 { 226 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family)); 227 } 228 229 /** 230 * genlmsg_put_reply - Add generic netlink header to a reply message 231 * @skb: socket buffer holding the message 232 * @info: receiver info 233 * @family: generic netlink family 234 * @flags: netlink message flags 235 * @cmd: generic netlink command 236 * 237 * Returns pointer to user specific header 238 */ 239 static inline void *genlmsg_put_reply(struct sk_buff *skb, 240 struct genl_info *info, 241 struct genl_family *family, 242 int flags, u8 cmd) 243 { 244 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family, 245 flags, cmd); 246 } 247 248 /** 249 * genlmsg_end - Finalize a generic netlink message 250 * @skb: socket buffer the message is stored in 251 * @hdr: user specific header 252 */ 253 static inline int genlmsg_end(struct sk_buff *skb, void *hdr) 254 { 255 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 256 } 257 258 /** 259 * genlmsg_cancel - Cancel construction of a generic netlink message 260 * @skb: socket buffer the message is stored in 261 * @hdr: generic netlink message header 262 */ 263 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 264 { 265 if (hdr) 266 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 267 } 268 269 /** 270 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 271 * @family: the generic netlink family 272 * @net: the net namespace 273 * @skb: netlink message as socket buffer 274 * @portid: own netlink portid to avoid sending to yourself 275 * @group: offset of multicast group in groups array 276 * @flags: allocation flags 277 */ 278 static inline int genlmsg_multicast_netns(struct genl_family *family, 279 struct net *net, struct sk_buff *skb, 280 u32 portid, unsigned int group, gfp_t flags) 281 { 282 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 283 return -EINVAL; 284 group = family->mcgrp_offset + group; 285 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags); 286 } 287 288 /** 289 * genlmsg_multicast - multicast a netlink message to the default netns 290 * @family: the generic netlink family 291 * @skb: netlink message as socket buffer 292 * @portid: own netlink portid to avoid sending to yourself 293 * @group: offset of multicast group in groups array 294 * @flags: allocation flags 295 */ 296 static inline int genlmsg_multicast(struct genl_family *family, 297 struct sk_buff *skb, u32 portid, 298 unsigned int group, gfp_t flags) 299 { 300 return genlmsg_multicast_netns(family, &init_net, skb, 301 portid, group, flags); 302 } 303 304 /** 305 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 306 * @family: the generic netlink family 307 * @skb: netlink message as socket buffer 308 * @portid: own netlink portid to avoid sending to yourself 309 * @group: offset of multicast group in groups array 310 * @flags: allocation flags 311 * 312 * This function must hold the RTNL or rcu_read_lock(). 313 */ 314 int genlmsg_multicast_allns(struct genl_family *family, 315 struct sk_buff *skb, u32 portid, 316 unsigned int group, gfp_t flags); 317 318 /** 319 * genlmsg_unicast - unicast a netlink message 320 * @skb: netlink message as socket buffer 321 * @portid: netlink portid of the destination socket 322 */ 323 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid) 324 { 325 return nlmsg_unicast(net->genl_sock, skb, portid); 326 } 327 328 /** 329 * genlmsg_reply - reply to a request 330 * @skb: netlink message to be sent back 331 * @info: receiver information 332 */ 333 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 334 { 335 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid); 336 } 337 338 /** 339 * gennlmsg_data - head of message payload 340 * @gnlh: genetlink message header 341 */ 342 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 343 { 344 return ((unsigned char *) gnlh + GENL_HDRLEN); 345 } 346 347 /** 348 * genlmsg_len - length of message payload 349 * @gnlh: genetlink message header 350 */ 351 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 352 { 353 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 354 NLMSG_HDRLEN); 355 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 356 } 357 358 /** 359 * genlmsg_msg_size - length of genetlink message not including padding 360 * @payload: length of message payload 361 */ 362 static inline int genlmsg_msg_size(int payload) 363 { 364 return GENL_HDRLEN + payload; 365 } 366 367 /** 368 * genlmsg_total_size - length of genetlink message including padding 369 * @payload: length of message payload 370 */ 371 static inline int genlmsg_total_size(int payload) 372 { 373 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 374 } 375 376 /** 377 * genlmsg_new - Allocate a new generic netlink message 378 * @payload: size of the message payload 379 * @flags: the type of memory to allocate. 380 */ 381 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 382 { 383 return nlmsg_new(genlmsg_total_size(payload), flags); 384 } 385 386 /** 387 * genl_set_err - report error to genetlink broadcast listeners 388 * @family: the generic netlink family 389 * @net: the network namespace to report the error to 390 * @portid: the PORTID of a process that we want to skip (if any) 391 * @group: the broadcast group that will notice the error 392 * (this is the offset of the multicast group in the groups array) 393 * @code: error code, must be negative (as usual in kernelspace) 394 * 395 * This function returns the number of broadcast listeners that have set the 396 * NETLINK_RECV_NO_ENOBUFS socket option. 397 */ 398 static inline int genl_set_err(struct genl_family *family, struct net *net, 399 u32 portid, u32 group, int code) 400 { 401 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 402 return -EINVAL; 403 group = family->mcgrp_offset + group; 404 return netlink_set_err(net->genl_sock, portid, group, code); 405 } 406 407 static inline int genl_has_listeners(struct genl_family *family, 408 struct net *net, unsigned int group) 409 { 410 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 411 return -EINVAL; 412 group = family->mcgrp_offset + group; 413 return netlink_has_listeners(net->genl_sock, group); 414 } 415 #endif /* __NET_GENERIC_NETLINK_H */ 416