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 * @pre_doit: called before an operation's doit callback, it may 31 * do additional, common, filtering and return an error 32 * @post_doit: called after an operation's doit callback, it may 33 * undo operations done by pre_doit, for example release locks 34 * @mcast_bind: a socket bound to the given multicast group (which 35 * is given as the offset into the groups array) 36 * @mcast_unbind: a socket was unbound from the given multicast group 37 * @attrbuf: buffer to store parsed attributes 38 * @family_list: family list 39 * @mcgrps: multicast groups used by this family (private) 40 * @n_mcgrps: number of multicast groups (private) 41 * @mcgrp_offset: starting number of multicast group IDs in this family 42 * @ops: the operations supported by this family (private) 43 * @n_ops: number of operations supported by this family (private) 44 */ 45 struct genl_family { 46 unsigned int id; 47 unsigned int hdrsize; 48 char name[GENL_NAMSIZ]; 49 unsigned int version; 50 unsigned int maxattr; 51 bool netnsok; 52 bool parallel_ops; 53 int (*pre_doit)(const struct genl_ops *ops, 54 struct sk_buff *skb, 55 struct genl_info *info); 56 void (*post_doit)(const struct genl_ops *ops, 57 struct sk_buff *skb, 58 struct genl_info *info); 59 int (*mcast_bind)(struct net *net, int group); 60 void (*mcast_unbind)(struct net *net, int group); 61 struct nlattr ** attrbuf; /* private */ 62 const struct genl_ops * ops; /* private */ 63 const struct genl_multicast_group *mcgrps; /* private */ 64 unsigned int n_ops; /* private */ 65 unsigned int n_mcgrps; /* private */ 66 unsigned int mcgrp_offset; /* private */ 67 struct list_head family_list; /* private */ 68 struct module *module; 69 }; 70 71 /** 72 * struct genl_info - receiving information 73 * @snd_seq: sending sequence number 74 * @snd_portid: netlink portid of sender 75 * @nlhdr: netlink message header 76 * @genlhdr: generic netlink message header 77 * @userhdr: user specific header 78 * @attrs: netlink attributes 79 * @_net: network namespace 80 * @user_ptr: user pointers 81 * @dst_sk: destination socket 82 */ 83 struct genl_info { 84 u32 snd_seq; 85 u32 snd_portid; 86 struct nlmsghdr * nlhdr; 87 struct genlmsghdr * genlhdr; 88 void * userhdr; 89 struct nlattr ** attrs; 90 #ifdef CONFIG_NET_NS 91 struct net * _net; 92 #endif 93 void * user_ptr[2]; 94 struct sock * dst_sk; 95 }; 96 97 static inline struct net *genl_info_net(struct genl_info *info) 98 { 99 return read_pnet(&info->_net); 100 } 101 102 static inline void genl_info_net_set(struct genl_info *info, struct net *net) 103 { 104 write_pnet(&info->_net, net); 105 } 106 107 /** 108 * struct genl_ops - generic netlink operations 109 * @cmd: command identifier 110 * @internal_flags: flags used by the family 111 * @flags: flags 112 * @policy: attribute validation policy 113 * @doit: standard command callback 114 * @dumpit: callback for dumpers 115 * @done: completion callback for dumps 116 * @ops_list: operations list 117 */ 118 struct genl_ops { 119 const struct nla_policy *policy; 120 int (*doit)(struct sk_buff *skb, 121 struct genl_info *info); 122 int (*dumpit)(struct sk_buff *skb, 123 struct netlink_callback *cb); 124 int (*done)(struct netlink_callback *cb); 125 u8 cmd; 126 u8 internal_flags; 127 u8 flags; 128 }; 129 130 int __genl_register_family(struct genl_family *family); 131 132 static inline int genl_register_family(struct genl_family *family) 133 { 134 family->module = THIS_MODULE; 135 return __genl_register_family(family); 136 } 137 138 /** 139 * genl_register_family_with_ops - register a generic netlink family with ops 140 * @family: generic netlink family 141 * @ops: operations to be registered 142 * @n_ops: number of elements to register 143 * 144 * Registers the specified family and operations from the specified table. 145 * Only one family may be registered with the same family name or identifier. 146 * 147 * The family id may equal GENL_ID_GENERATE causing an unique id to 148 * be automatically generated and assigned. 149 * 150 * Either a doit or dumpit callback must be specified for every registered 151 * operation or the function will fail. Only one operation structure per 152 * command identifier may be registered. 153 * 154 * See include/net/genetlink.h for more documenation on the operations 155 * structure. 156 * 157 * Return 0 on success or a negative error code. 158 */ 159 static inline int 160 _genl_register_family_with_ops_grps(struct genl_family *family, 161 const struct genl_ops *ops, size_t n_ops, 162 const struct genl_multicast_group *mcgrps, 163 size_t n_mcgrps) 164 { 165 family->module = THIS_MODULE; 166 family->ops = ops; 167 family->n_ops = n_ops; 168 family->mcgrps = mcgrps; 169 family->n_mcgrps = n_mcgrps; 170 return __genl_register_family(family); 171 } 172 173 #define genl_register_family_with_ops(family, ops) \ 174 _genl_register_family_with_ops_grps((family), \ 175 (ops), ARRAY_SIZE(ops), \ 176 NULL, 0) 177 #define genl_register_family_with_ops_groups(family, ops, grps) \ 178 _genl_register_family_with_ops_grps((family), \ 179 (ops), ARRAY_SIZE(ops), \ 180 (grps), ARRAY_SIZE(grps)) 181 182 int genl_unregister_family(struct genl_family *family); 183 void genl_notify(struct genl_family *family, 184 struct sk_buff *skb, struct net *net, u32 portid, 185 u32 group, struct nlmsghdr *nlh, gfp_t flags); 186 187 struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, 188 gfp_t flags); 189 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 190 struct genl_family *family, int flags, u8 cmd); 191 192 /** 193 * genlmsg_nlhdr - Obtain netlink header from user specified header 194 * @user_hdr: user header as returned from genlmsg_put() 195 * @family: generic netlink family 196 * 197 * Returns pointer to netlink header. 198 */ 199 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr, 200 struct genl_family *family) 201 { 202 return (struct nlmsghdr *)((char *)user_hdr - 203 family->hdrsize - 204 GENL_HDRLEN - 205 NLMSG_HDRLEN); 206 } 207 208 /** 209 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 210 * @cb: netlink callback structure that stores the sequence number 211 * @user_hdr: user header as returned from genlmsg_put() 212 * @family: generic netlink family 213 * 214 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 215 * simpler to use with generic netlink. 216 */ 217 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 218 void *user_hdr, 219 struct genl_family *family) 220 { 221 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family)); 222 } 223 224 /** 225 * genlmsg_put_reply - Add generic netlink header to a reply message 226 * @skb: socket buffer holding the message 227 * @info: receiver info 228 * @family: generic netlink family 229 * @flags: netlink message flags 230 * @cmd: generic netlink command 231 * 232 * Returns pointer to user specific header 233 */ 234 static inline void *genlmsg_put_reply(struct sk_buff *skb, 235 struct genl_info *info, 236 struct genl_family *family, 237 int flags, u8 cmd) 238 { 239 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family, 240 flags, cmd); 241 } 242 243 /** 244 * genlmsg_end - Finalize a generic netlink message 245 * @skb: socket buffer the message is stored in 246 * @hdr: user specific header 247 */ 248 static inline int genlmsg_end(struct sk_buff *skb, void *hdr) 249 { 250 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 251 } 252 253 /** 254 * genlmsg_cancel - Cancel construction of a generic netlink message 255 * @skb: socket buffer the message is stored in 256 * @hdr: generic netlink message header 257 */ 258 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 259 { 260 if (hdr) 261 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 262 } 263 264 /** 265 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 266 * @family: the generic netlink family 267 * @net: the net namespace 268 * @skb: netlink message as socket buffer 269 * @portid: own netlink portid to avoid sending to yourself 270 * @group: offset of multicast group in groups array 271 * @flags: allocation flags 272 */ 273 static inline int genlmsg_multicast_netns(struct genl_family *family, 274 struct net *net, struct sk_buff *skb, 275 u32 portid, unsigned int group, gfp_t flags) 276 { 277 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 278 return -EINVAL; 279 group = family->mcgrp_offset + group; 280 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags); 281 } 282 283 /** 284 * genlmsg_multicast - multicast a netlink message to the default netns 285 * @family: the generic netlink family 286 * @skb: netlink message as socket buffer 287 * @portid: own netlink portid to avoid sending to yourself 288 * @group: offset of multicast group in groups array 289 * @flags: allocation flags 290 */ 291 static inline int genlmsg_multicast(struct genl_family *family, 292 struct sk_buff *skb, u32 portid, 293 unsigned int group, gfp_t flags) 294 { 295 return genlmsg_multicast_netns(family, &init_net, skb, 296 portid, group, flags); 297 } 298 299 /** 300 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 301 * @family: the generic netlink family 302 * @skb: netlink message as socket buffer 303 * @portid: own netlink portid to avoid sending to yourself 304 * @group: offset of multicast group in groups array 305 * @flags: allocation flags 306 * 307 * This function must hold the RTNL or rcu_read_lock(). 308 */ 309 int genlmsg_multicast_allns(struct genl_family *family, 310 struct sk_buff *skb, u32 portid, 311 unsigned int group, gfp_t flags); 312 313 /** 314 * genlmsg_unicast - unicast a netlink message 315 * @skb: netlink message as socket buffer 316 * @portid: netlink portid of the destination socket 317 */ 318 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid) 319 { 320 return nlmsg_unicast(net->genl_sock, skb, portid); 321 } 322 323 /** 324 * genlmsg_reply - reply to a request 325 * @skb: netlink message to be sent back 326 * @info: receiver information 327 */ 328 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 329 { 330 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid); 331 } 332 333 /** 334 * gennlmsg_data - head of message payload 335 * @gnlh: genetlink message header 336 */ 337 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 338 { 339 return ((unsigned char *) gnlh + GENL_HDRLEN); 340 } 341 342 /** 343 * genlmsg_len - length of message payload 344 * @gnlh: genetlink message header 345 */ 346 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 347 { 348 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 349 NLMSG_HDRLEN); 350 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 351 } 352 353 /** 354 * genlmsg_msg_size - length of genetlink message not including padding 355 * @payload: length of message payload 356 */ 357 static inline int genlmsg_msg_size(int payload) 358 { 359 return GENL_HDRLEN + payload; 360 } 361 362 /** 363 * genlmsg_total_size - length of genetlink message including padding 364 * @payload: length of message payload 365 */ 366 static inline int genlmsg_total_size(int payload) 367 { 368 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 369 } 370 371 /** 372 * genlmsg_new - Allocate a new generic netlink message 373 * @payload: size of the message payload 374 * @flags: the type of memory to allocate. 375 */ 376 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 377 { 378 return nlmsg_new(genlmsg_total_size(payload), flags); 379 } 380 381 /** 382 * genl_set_err - report error to genetlink broadcast listeners 383 * @family: the generic netlink family 384 * @net: the network namespace to report the error to 385 * @portid: the PORTID of a process that we want to skip (if any) 386 * @group: the broadcast group that will notice the error 387 * (this is the offset of the multicast group in the groups array) 388 * @code: error code, must be negative (as usual in kernelspace) 389 * 390 * This function returns the number of broadcast listeners that have set the 391 * NETLINK_RECV_NO_ENOBUFS socket option. 392 */ 393 static inline int genl_set_err(struct genl_family *family, struct net *net, 394 u32 portid, u32 group, int code) 395 { 396 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 397 return -EINVAL; 398 group = family->mcgrp_offset + group; 399 return netlink_set_err(net->genl_sock, portid, group, code); 400 } 401 402 static inline int genl_has_listeners(struct genl_family *family, 403 struct net *net, unsigned int group) 404 { 405 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 406 return -EINVAL; 407 group = family->mcgrp_offset + group; 408 return netlink_has_listeners(net->genl_sock, group); 409 } 410 #endif /* __NET_GENERIC_NETLINK_H */ 411