1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __NET_GENERIC_NETLINK_H 3 #define __NET_GENERIC_NETLINK_H 4 5 #include <linux/genetlink.h> 6 #include <net/netlink.h> 7 #include <net/net_namespace.h> 8 9 #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN) 10 11 /** 12 * struct genl_multicast_group - generic netlink multicast group 13 * @name: name of the multicast group, names are per-family 14 */ 15 struct genl_multicast_group { 16 char name[GENL_NAMSIZ]; 17 }; 18 19 struct genl_ops; 20 struct genl_info; 21 22 /** 23 * struct genl_family - generic netlink family 24 * @id: protocol family identifier (private) 25 * @hdrsize: length of user specific header in bytes 26 * @name: name of family 27 * @version: protocol version 28 * @maxattr: maximum number of attributes supported 29 * @policy: netlink policy 30 * @netnsok: set to true if the family can handle network 31 * namespaces and should be presented in all of them 32 * @parallel_ops: operations can be called in parallel and aren't 33 * synchronized by the core genetlink code 34 * @pre_doit: called before an operation's doit callback, it may 35 * do additional, common, filtering and return an error 36 * @post_doit: called after an operation's doit callback, it may 37 * undo operations done by pre_doit, for example release locks 38 * @mcgrps: multicast groups used by this family 39 * @n_mcgrps: number of multicast groups 40 * @mcgrp_offset: starting number of multicast group IDs in this family 41 * (private) 42 * @ops: the operations supported by this family 43 * @n_ops: number of operations supported by this family 44 * @small_ops: the small-struct operations supported by this family 45 * @n_small_ops: number of small-struct operations supported by this family 46 */ 47 struct genl_family { 48 int id; /* private */ 49 unsigned int hdrsize; 50 char name[GENL_NAMSIZ]; 51 unsigned int version; 52 unsigned int maxattr; 53 unsigned int mcgrp_offset; /* private */ 54 u8 netnsok:1; 55 u8 parallel_ops:1; 56 u8 n_ops; 57 u8 n_small_ops; 58 u8 n_mcgrps; 59 const struct nla_policy *policy; 60 int (*pre_doit)(const struct genl_ops *ops, 61 struct sk_buff *skb, 62 struct genl_info *info); 63 void (*post_doit)(const struct genl_ops *ops, 64 struct sk_buff *skb, 65 struct genl_info *info); 66 const struct genl_ops * ops; 67 const struct genl_small_ops *small_ops; 68 const struct genl_multicast_group *mcgrps; 69 struct module *module; 70 }; 71 72 /** 73 * struct genl_info - receiving information 74 * @snd_seq: sending sequence number 75 * @snd_portid: netlink portid of sender 76 * @nlhdr: netlink message header 77 * @genlhdr: generic netlink message header 78 * @userhdr: user specific header 79 * @attrs: netlink attributes 80 * @_net: network namespace 81 * @user_ptr: user pointers 82 * @extack: extended ACK report struct 83 */ 84 struct genl_info { 85 u32 snd_seq; 86 u32 snd_portid; 87 struct nlmsghdr * nlhdr; 88 struct genlmsghdr * genlhdr; 89 void * userhdr; 90 struct nlattr ** attrs; 91 possible_net_t _net; 92 void * user_ptr[2]; 93 struct netlink_ext_ack *extack; 94 }; 95 96 static inline struct net *genl_info_net(struct genl_info *info) 97 { 98 return read_pnet(&info->_net); 99 } 100 101 static inline void genl_info_net_set(struct genl_info *info, struct net *net) 102 { 103 write_pnet(&info->_net, net); 104 } 105 106 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg) 107 108 enum genl_validate_flags { 109 GENL_DONT_VALIDATE_STRICT = BIT(0), 110 GENL_DONT_VALIDATE_DUMP = BIT(1), 111 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2), 112 }; 113 114 /** 115 * struct genl_small_ops - generic netlink operations (small version) 116 * @cmd: command identifier 117 * @internal_flags: flags used by the family 118 * @flags: flags 119 * @validate: validation flags from enum genl_validate_flags 120 * @doit: standard command callback 121 * @dumpit: callback for dumpers 122 * 123 * This is a cut-down version of struct genl_ops for users who don't need 124 * most of the ancillary infra and want to save space. 125 */ 126 struct genl_small_ops { 127 int (*doit)(struct sk_buff *skb, struct genl_info *info); 128 int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb); 129 u8 cmd; 130 u8 internal_flags; 131 u8 flags; 132 u8 validate; 133 }; 134 135 /** 136 * struct genl_ops - generic netlink operations 137 * @cmd: command identifier 138 * @internal_flags: flags used by the family 139 * @flags: flags 140 * @maxattr: maximum number of attributes supported 141 * @policy: netlink policy (takes precedence over family policy) 142 * @validate: validation flags from enum genl_validate_flags 143 * @doit: standard command callback 144 * @start: start callback for dumps 145 * @dumpit: callback for dumpers 146 * @done: completion callback for dumps 147 */ 148 struct genl_ops { 149 int (*doit)(struct sk_buff *skb, 150 struct genl_info *info); 151 int (*start)(struct netlink_callback *cb); 152 int (*dumpit)(struct sk_buff *skb, 153 struct netlink_callback *cb); 154 int (*done)(struct netlink_callback *cb); 155 const struct nla_policy *policy; 156 unsigned int maxattr; 157 u8 cmd; 158 u8 internal_flags; 159 u8 flags; 160 u8 validate; 161 }; 162 163 /** 164 * struct genl_info - info that is available during dumpit op call 165 * @family: generic netlink family - for internal genl code usage 166 * @ops: generic netlink ops - for internal genl code usage 167 * @attrs: netlink attributes 168 */ 169 struct genl_dumpit_info { 170 const struct genl_family *family; 171 struct genl_ops op; 172 struct nlattr **attrs; 173 }; 174 175 static inline const struct genl_dumpit_info * 176 genl_dumpit_info(struct netlink_callback *cb) 177 { 178 return cb->data; 179 } 180 181 int genl_register_family(struct genl_family *family); 182 int genl_unregister_family(const struct genl_family *family); 183 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 184 struct genl_info *info, u32 group, gfp_t flags); 185 186 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 187 const struct genl_family *family, int flags, u8 cmd); 188 189 /** 190 * genlmsg_nlhdr - Obtain netlink header from user specified header 191 * @user_hdr: user header as returned from genlmsg_put() 192 * 193 * Returns pointer to netlink header. 194 */ 195 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr) 196 { 197 return (struct nlmsghdr *)((char *)user_hdr - 198 GENL_HDRLEN - 199 NLMSG_HDRLEN); 200 } 201 202 /** 203 * genlmsg_parse_deprecated - parse attributes of a genetlink message 204 * @nlh: netlink message header 205 * @family: genetlink message family 206 * @tb: destination array with maxtype+1 elements 207 * @maxtype: maximum attribute type to be expected 208 * @policy: validation policy 209 * @extack: extended ACK report struct 210 */ 211 static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh, 212 const struct genl_family *family, 213 struct nlattr *tb[], int maxtype, 214 const struct nla_policy *policy, 215 struct netlink_ext_ack *extack) 216 { 217 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 218 policy, NL_VALIDATE_LIBERAL, extack); 219 } 220 221 /** 222 * genlmsg_parse - parse attributes of a genetlink message 223 * @nlh: netlink message header 224 * @family: genetlink message family 225 * @tb: destination array with maxtype+1 elements 226 * @maxtype: maximum attribute type to be expected 227 * @policy: validation policy 228 * @extack: extended ACK report struct 229 */ 230 static inline int genlmsg_parse(const struct nlmsghdr *nlh, 231 const struct genl_family *family, 232 struct nlattr *tb[], int maxtype, 233 const struct nla_policy *policy, 234 struct netlink_ext_ack *extack) 235 { 236 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 237 policy, NL_VALIDATE_STRICT, extack); 238 } 239 240 /** 241 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 242 * @cb: netlink callback structure that stores the sequence number 243 * @user_hdr: user header as returned from genlmsg_put() 244 * 245 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 246 * simpler to use with generic netlink. 247 */ 248 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 249 void *user_hdr) 250 { 251 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr)); 252 } 253 254 /** 255 * genlmsg_put_reply - Add generic netlink header to a reply message 256 * @skb: socket buffer holding the message 257 * @info: receiver info 258 * @family: generic netlink family 259 * @flags: netlink message flags 260 * @cmd: generic netlink command 261 * 262 * Returns pointer to user specific header 263 */ 264 static inline void *genlmsg_put_reply(struct sk_buff *skb, 265 struct genl_info *info, 266 const struct genl_family *family, 267 int flags, u8 cmd) 268 { 269 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family, 270 flags, cmd); 271 } 272 273 /** 274 * genlmsg_end - Finalize a generic netlink message 275 * @skb: socket buffer the message is stored in 276 * @hdr: user specific header 277 */ 278 static inline void genlmsg_end(struct sk_buff *skb, void *hdr) 279 { 280 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 281 } 282 283 /** 284 * genlmsg_cancel - Cancel construction of a generic netlink message 285 * @skb: socket buffer the message is stored in 286 * @hdr: generic netlink message header 287 */ 288 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 289 { 290 if (hdr) 291 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 292 } 293 294 /** 295 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 296 * @family: the generic netlink family 297 * @net: the net namespace 298 * @skb: netlink message as socket buffer 299 * @portid: own netlink portid to avoid sending to yourself 300 * @group: offset of multicast group in groups array 301 * @flags: allocation flags 302 */ 303 static inline int genlmsg_multicast_netns(const struct genl_family *family, 304 struct net *net, struct sk_buff *skb, 305 u32 portid, unsigned int group, gfp_t flags) 306 { 307 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 308 return -EINVAL; 309 group = family->mcgrp_offset + group; 310 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags); 311 } 312 313 /** 314 * genlmsg_multicast - multicast a netlink message to the default netns 315 * @family: the generic netlink family 316 * @skb: netlink message as socket buffer 317 * @portid: own netlink portid to avoid sending to yourself 318 * @group: offset of multicast group in groups array 319 * @flags: allocation flags 320 */ 321 static inline int genlmsg_multicast(const struct genl_family *family, 322 struct sk_buff *skb, u32 portid, 323 unsigned int group, gfp_t flags) 324 { 325 return genlmsg_multicast_netns(family, &init_net, skb, 326 portid, group, flags); 327 } 328 329 /** 330 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 331 * @family: the generic netlink family 332 * @skb: netlink message as socket buffer 333 * @portid: own netlink portid to avoid sending to yourself 334 * @group: offset of multicast group in groups array 335 * @flags: allocation flags 336 * 337 * This function must hold the RTNL or rcu_read_lock(). 338 */ 339 int genlmsg_multicast_allns(const struct genl_family *family, 340 struct sk_buff *skb, u32 portid, 341 unsigned int group, gfp_t flags); 342 343 /** 344 * genlmsg_unicast - unicast a netlink message 345 * @skb: netlink message as socket buffer 346 * @portid: netlink portid of the destination socket 347 */ 348 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid) 349 { 350 return nlmsg_unicast(net->genl_sock, skb, portid); 351 } 352 353 /** 354 * genlmsg_reply - reply to a request 355 * @skb: netlink message to be sent back 356 * @info: receiver information 357 */ 358 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 359 { 360 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid); 361 } 362 363 /** 364 * gennlmsg_data - head of message payload 365 * @gnlh: genetlink message header 366 */ 367 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 368 { 369 return ((unsigned char *) gnlh + GENL_HDRLEN); 370 } 371 372 /** 373 * genlmsg_len - length of message payload 374 * @gnlh: genetlink message header 375 */ 376 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 377 { 378 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 379 NLMSG_HDRLEN); 380 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 381 } 382 383 /** 384 * genlmsg_msg_size - length of genetlink message not including padding 385 * @payload: length of message payload 386 */ 387 static inline int genlmsg_msg_size(int payload) 388 { 389 return GENL_HDRLEN + payload; 390 } 391 392 /** 393 * genlmsg_total_size - length of genetlink message including padding 394 * @payload: length of message payload 395 */ 396 static inline int genlmsg_total_size(int payload) 397 { 398 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 399 } 400 401 /** 402 * genlmsg_new - Allocate a new generic netlink message 403 * @payload: size of the message payload 404 * @flags: the type of memory to allocate. 405 */ 406 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 407 { 408 return nlmsg_new(genlmsg_total_size(payload), flags); 409 } 410 411 /** 412 * genl_set_err - report error to genetlink broadcast listeners 413 * @family: the generic netlink family 414 * @net: the network namespace to report the error to 415 * @portid: the PORTID of a process that we want to skip (if any) 416 * @group: the broadcast group that will notice the error 417 * (this is the offset of the multicast group in the groups array) 418 * @code: error code, must be negative (as usual in kernelspace) 419 * 420 * This function returns the number of broadcast listeners that have set the 421 * NETLINK_RECV_NO_ENOBUFS socket option. 422 */ 423 static inline int genl_set_err(const struct genl_family *family, 424 struct net *net, u32 portid, 425 u32 group, int code) 426 { 427 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 428 return -EINVAL; 429 group = family->mcgrp_offset + group; 430 return netlink_set_err(net->genl_sock, portid, group, code); 431 } 432 433 static inline int genl_has_listeners(const struct genl_family *family, 434 struct net *net, unsigned int group) 435 { 436 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 437 return -EINVAL; 438 group = family->mcgrp_offset + group; 439 return netlink_has_listeners(net->genl_sock, group); 440 } 441 #endif /* __NET_GENERIC_NETLINK_H */ 442