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