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 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) 15 */ 16 struct genl_multicast_group { 17 char name[GENL_NAMSIZ]; 18 u8 flags; 19 }; 20 21 struct genl_ops; 22 struct genl_info; 23 24 /** 25 * struct genl_family - generic netlink family 26 * @id: protocol family identifier (private) 27 * @hdrsize: length of user specific header in bytes 28 * @name: name of family 29 * @version: protocol version 30 * @maxattr: maximum number of attributes supported 31 * @policy: netlink policy 32 * @netnsok: set to true if the family can handle network 33 * namespaces and should be presented in all of them 34 * @parallel_ops: operations can be called in parallel and aren't 35 * synchronized by the core genetlink code 36 * @pre_doit: called before an operation's doit callback, it may 37 * do additional, common, filtering and return an error 38 * @post_doit: called after an operation's doit callback, it may 39 * undo operations done by pre_doit, for example release locks 40 * @mcgrps: multicast groups used by this family 41 * @n_mcgrps: number of multicast groups 42 * @mcgrp_offset: starting number of multicast group IDs in this family 43 * (private) 44 * @ops: the operations supported by this family 45 * @n_ops: number of operations supported by this family 46 * @small_ops: the small-struct operations supported by this family 47 * @n_small_ops: number of small-struct operations supported by this family 48 */ 49 struct genl_family { 50 int id; /* private */ 51 unsigned int hdrsize; 52 char name[GENL_NAMSIZ]; 53 unsigned int version; 54 unsigned int maxattr; 55 unsigned int mcgrp_offset; /* private */ 56 u8 netnsok:1; 57 u8 parallel_ops:1; 58 u8 n_ops; 59 u8 n_small_ops; 60 u8 n_mcgrps; 61 const struct nla_policy *policy; 62 int (*pre_doit)(const struct genl_ops *ops, 63 struct sk_buff *skb, 64 struct genl_info *info); 65 void (*post_doit)(const struct genl_ops *ops, 66 struct sk_buff *skb, 67 struct genl_info *info); 68 const struct genl_ops * ops; 69 const struct genl_small_ops *small_ops; 70 const struct genl_multicast_group *mcgrps; 71 struct module *module; 72 }; 73 74 /** 75 * struct genl_info - receiving information 76 * @snd_seq: sending sequence number 77 * @snd_portid: netlink portid of sender 78 * @nlhdr: netlink message header 79 * @genlhdr: generic netlink message header 80 * @userhdr: user specific header 81 * @attrs: netlink attributes 82 * @_net: network namespace 83 * @user_ptr: user pointers 84 * @extack: extended ACK report struct 85 */ 86 struct genl_info { 87 u32 snd_seq; 88 u32 snd_portid; 89 struct nlmsghdr * nlhdr; 90 struct genlmsghdr * genlhdr; 91 void * userhdr; 92 struct nlattr ** attrs; 93 possible_net_t _net; 94 void * user_ptr[2]; 95 struct netlink_ext_ack *extack; 96 }; 97 98 static inline struct net *genl_info_net(struct genl_info *info) 99 { 100 return read_pnet(&info->_net); 101 } 102 103 static inline void genl_info_net_set(struct genl_info *info, struct net *net) 104 { 105 write_pnet(&info->_net, net); 106 } 107 108 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg) 109 110 enum genl_validate_flags { 111 GENL_DONT_VALIDATE_STRICT = BIT(0), 112 GENL_DONT_VALIDATE_DUMP = BIT(1), 113 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2), 114 }; 115 116 /** 117 * struct genl_small_ops - generic netlink operations (small version) 118 * @cmd: command identifier 119 * @internal_flags: flags used by the family 120 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) 121 * @validate: validation flags from enum genl_validate_flags 122 * @doit: standard command callback 123 * @dumpit: callback for dumpers 124 * 125 * This is a cut-down version of struct genl_ops for users who don't need 126 * most of the ancillary infra and want to save space. 127 */ 128 struct genl_small_ops { 129 int (*doit)(struct sk_buff *skb, struct genl_info *info); 130 int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb); 131 u8 cmd; 132 u8 internal_flags; 133 u8 flags; 134 u8 validate; 135 }; 136 137 /** 138 * struct genl_ops - generic netlink operations 139 * @cmd: command identifier 140 * @internal_flags: flags used by the family 141 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) 142 * @maxattr: maximum number of attributes supported 143 * @policy: netlink policy (takes precedence over family policy) 144 * @validate: validation flags from enum genl_validate_flags 145 * @doit: standard command callback 146 * @start: start callback for dumps 147 * @dumpit: callback for dumpers 148 * @done: completion callback for dumps 149 */ 150 struct genl_ops { 151 int (*doit)(struct sk_buff *skb, 152 struct genl_info *info); 153 int (*start)(struct netlink_callback *cb); 154 int (*dumpit)(struct sk_buff *skb, 155 struct netlink_callback *cb); 156 int (*done)(struct netlink_callback *cb); 157 const struct nla_policy *policy; 158 unsigned int maxattr; 159 u8 cmd; 160 u8 internal_flags; 161 u8 flags; 162 u8 validate; 163 }; 164 165 /** 166 * struct genl_info - info that is available during dumpit op call 167 * @family: generic netlink family - for internal genl code usage 168 * @ops: generic netlink ops - for internal genl code usage 169 * @attrs: netlink attributes 170 */ 171 struct genl_dumpit_info { 172 const struct genl_family *family; 173 struct genl_ops op; 174 struct nlattr **attrs; 175 }; 176 177 static inline const struct genl_dumpit_info * 178 genl_dumpit_info(struct netlink_callback *cb) 179 { 180 return cb->data; 181 } 182 183 int genl_register_family(struct genl_family *family); 184 int genl_unregister_family(const struct genl_family *family); 185 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 186 struct genl_info *info, u32 group, gfp_t flags); 187 188 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 189 const struct genl_family *family, int flags, u8 cmd); 190 191 /** 192 * genlmsg_nlhdr - Obtain netlink header from user specified header 193 * @user_hdr: user header as returned from genlmsg_put() 194 * 195 * Returns pointer to netlink header. 196 */ 197 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr) 198 { 199 return (struct nlmsghdr *)((char *)user_hdr - 200 GENL_HDRLEN - 201 NLMSG_HDRLEN); 202 } 203 204 /** 205 * genlmsg_parse_deprecated - parse attributes of a genetlink message 206 * @nlh: netlink message header 207 * @family: genetlink message family 208 * @tb: destination array with maxtype+1 elements 209 * @maxtype: maximum attribute type to be expected 210 * @policy: validation policy 211 * @extack: extended ACK report struct 212 */ 213 static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh, 214 const struct genl_family *family, 215 struct nlattr *tb[], int maxtype, 216 const struct nla_policy *policy, 217 struct netlink_ext_ack *extack) 218 { 219 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 220 policy, NL_VALIDATE_LIBERAL, extack); 221 } 222 223 /** 224 * genlmsg_parse - parse attributes of a genetlink message 225 * @nlh: netlink message header 226 * @family: genetlink message family 227 * @tb: destination array with maxtype+1 elements 228 * @maxtype: maximum attribute type to be expected 229 * @policy: validation policy 230 * @extack: extended ACK report struct 231 */ 232 static inline int genlmsg_parse(const struct nlmsghdr *nlh, 233 const struct genl_family *family, 234 struct nlattr *tb[], int maxtype, 235 const struct nla_policy *policy, 236 struct netlink_ext_ack *extack) 237 { 238 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 239 policy, NL_VALIDATE_STRICT, extack); 240 } 241 242 /** 243 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 244 * @cb: netlink callback structure that stores the sequence number 245 * @user_hdr: user header as returned from genlmsg_put() 246 * 247 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 248 * simpler to use with generic netlink. 249 */ 250 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 251 void *user_hdr) 252 { 253 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr)); 254 } 255 256 /** 257 * genlmsg_put_reply - Add generic netlink header to a reply message 258 * @skb: socket buffer holding the message 259 * @info: receiver info 260 * @family: generic netlink family 261 * @flags: netlink message flags 262 * @cmd: generic netlink command 263 * 264 * Returns pointer to user specific header 265 */ 266 static inline void *genlmsg_put_reply(struct sk_buff *skb, 267 struct genl_info *info, 268 const struct genl_family *family, 269 int flags, u8 cmd) 270 { 271 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family, 272 flags, cmd); 273 } 274 275 /** 276 * genlmsg_end - Finalize a generic netlink message 277 * @skb: socket buffer the message is stored in 278 * @hdr: user specific header 279 */ 280 static inline void genlmsg_end(struct sk_buff *skb, void *hdr) 281 { 282 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 283 } 284 285 /** 286 * genlmsg_cancel - Cancel construction of a generic netlink message 287 * @skb: socket buffer the message is stored in 288 * @hdr: generic netlink message header 289 */ 290 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 291 { 292 if (hdr) 293 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 294 } 295 296 /** 297 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 298 * @family: the generic netlink family 299 * @net: the net namespace 300 * @skb: netlink message as socket buffer 301 * @portid: own netlink portid to avoid sending to yourself 302 * @group: offset of multicast group in groups array 303 * @flags: allocation flags 304 */ 305 static inline int genlmsg_multicast_netns(const struct genl_family *family, 306 struct net *net, struct sk_buff *skb, 307 u32 portid, unsigned int group, gfp_t flags) 308 { 309 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 310 return -EINVAL; 311 group = family->mcgrp_offset + group; 312 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags); 313 } 314 315 /** 316 * genlmsg_multicast - multicast a netlink message to the default netns 317 * @family: the generic netlink family 318 * @skb: netlink message as socket buffer 319 * @portid: own netlink portid to avoid sending to yourself 320 * @group: offset of multicast group in groups array 321 * @flags: allocation flags 322 */ 323 static inline int genlmsg_multicast(const struct genl_family *family, 324 struct sk_buff *skb, u32 portid, 325 unsigned int group, gfp_t flags) 326 { 327 return genlmsg_multicast_netns(family, &init_net, skb, 328 portid, group, flags); 329 } 330 331 /** 332 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 333 * @family: the generic netlink family 334 * @skb: netlink message as socket buffer 335 * @portid: own netlink portid to avoid sending to yourself 336 * @group: offset of multicast group in groups array 337 * @flags: allocation flags 338 * 339 * This function must hold the RTNL or rcu_read_lock(). 340 */ 341 int genlmsg_multicast_allns(const struct genl_family *family, 342 struct sk_buff *skb, u32 portid, 343 unsigned int group, gfp_t flags); 344 345 /** 346 * genlmsg_unicast - unicast a netlink message 347 * @skb: netlink message as socket buffer 348 * @portid: netlink portid of the destination socket 349 */ 350 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid) 351 { 352 return nlmsg_unicast(net->genl_sock, skb, portid); 353 } 354 355 /** 356 * genlmsg_reply - reply to a request 357 * @skb: netlink message to be sent back 358 * @info: receiver information 359 */ 360 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 361 { 362 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid); 363 } 364 365 /** 366 * gennlmsg_data - head of message payload 367 * @gnlh: genetlink message header 368 */ 369 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 370 { 371 return ((unsigned char *) gnlh + GENL_HDRLEN); 372 } 373 374 /** 375 * genlmsg_len - length of message payload 376 * @gnlh: genetlink message header 377 */ 378 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 379 { 380 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 381 NLMSG_HDRLEN); 382 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 383 } 384 385 /** 386 * genlmsg_msg_size - length of genetlink message not including padding 387 * @payload: length of message payload 388 */ 389 static inline int genlmsg_msg_size(int payload) 390 { 391 return GENL_HDRLEN + payload; 392 } 393 394 /** 395 * genlmsg_total_size - length of genetlink message including padding 396 * @payload: length of message payload 397 */ 398 static inline int genlmsg_total_size(int payload) 399 { 400 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 401 } 402 403 /** 404 * genlmsg_new - Allocate a new generic netlink message 405 * @payload: size of the message payload 406 * @flags: the type of memory to allocate. 407 */ 408 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 409 { 410 return nlmsg_new(genlmsg_total_size(payload), flags); 411 } 412 413 /** 414 * genl_set_err - report error to genetlink broadcast listeners 415 * @family: the generic netlink family 416 * @net: the network namespace to report the error to 417 * @portid: the PORTID of a process that we want to skip (if any) 418 * @group: the broadcast group that will notice the error 419 * (this is the offset of the multicast group in the groups array) 420 * @code: error code, must be negative (as usual in kernelspace) 421 * 422 * This function returns the number of broadcast listeners that have set the 423 * NETLINK_RECV_NO_ENOBUFS socket option. 424 */ 425 static inline int genl_set_err(const struct genl_family *family, 426 struct net *net, u32 portid, 427 u32 group, int code) 428 { 429 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 430 return -EINVAL; 431 group = family->mcgrp_offset + group; 432 return netlink_set_err(net->genl_sock, portid, group, code); 433 } 434 435 static inline int genl_has_listeners(const struct genl_family *family, 436 struct net *net, unsigned int group) 437 { 438 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 439 return -EINVAL; 440 group = family->mcgrp_offset + group; 441 return netlink_has_listeners(net->genl_sock, group); 442 } 443 #endif /* __NET_GENERIC_NETLINK_H */ 444