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 enum genl_validate_flags { 105 GENL_DONT_VALIDATE_STRICT = BIT(0), 106 GENL_DONT_VALIDATE_DUMP = BIT(1), 107 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2), 108 }; 109 110 /** 111 * struct genl_info - info that is available during dumpit op call 112 * @family: generic netlink family - for internal genl code usage 113 * @ops: generic netlink ops - for internal genl code usage 114 * @attrs: netlink attributes 115 */ 116 struct genl_dumpit_info { 117 const struct genl_family *family; 118 const struct genl_ops *ops; 119 struct nlattr **attrs; 120 }; 121 122 static inline const struct genl_dumpit_info * 123 genl_dumpit_info(struct netlink_callback *cb) 124 { 125 return cb->data; 126 } 127 128 /** 129 * struct genl_ops - generic netlink operations 130 * @cmd: command identifier 131 * @internal_flags: flags used by the family 132 * @flags: flags 133 * @doit: standard command callback 134 * @start: start callback for dumps 135 * @dumpit: callback for dumpers 136 * @done: completion callback for dumps 137 */ 138 struct genl_ops { 139 int (*doit)(struct sk_buff *skb, 140 struct genl_info *info); 141 int (*start)(struct netlink_callback *cb); 142 int (*dumpit)(struct sk_buff *skb, 143 struct netlink_callback *cb); 144 int (*done)(struct netlink_callback *cb); 145 u8 cmd; 146 u8 internal_flags; 147 u8 flags; 148 u8 validate; 149 }; 150 151 int genl_register_family(struct genl_family *family); 152 int genl_unregister_family(const struct genl_family *family); 153 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 154 struct genl_info *info, u32 group, gfp_t flags); 155 156 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 157 const struct genl_family *family, int flags, u8 cmd); 158 159 /** 160 * genlmsg_nlhdr - Obtain netlink header from user specified header 161 * @user_hdr: user header as returned from genlmsg_put() 162 * 163 * Returns pointer to netlink header. 164 */ 165 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr) 166 { 167 return (struct nlmsghdr *)((char *)user_hdr - 168 GENL_HDRLEN - 169 NLMSG_HDRLEN); 170 } 171 172 /** 173 * genlmsg_parse_deprecated - parse attributes of a genetlink message 174 * @nlh: netlink message header 175 * @family: genetlink message family 176 * @tb: destination array with maxtype+1 elements 177 * @maxtype: maximum attribute type to be expected 178 * @policy: validation policy 179 * @extack: extended ACK report struct 180 */ 181 static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh, 182 const struct genl_family *family, 183 struct nlattr *tb[], int maxtype, 184 const struct nla_policy *policy, 185 struct netlink_ext_ack *extack) 186 { 187 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 188 policy, NL_VALIDATE_LIBERAL, extack); 189 } 190 191 /** 192 * genlmsg_parse - parse attributes of a genetlink message 193 * @nlh: netlink message header 194 * @family: genetlink message family 195 * @tb: destination array with maxtype+1 elements 196 * @maxtype: maximum attribute type to be expected 197 * @policy: validation policy 198 * @extack: extended ACK report struct 199 */ 200 static inline int genlmsg_parse(const struct nlmsghdr *nlh, 201 const struct genl_family *family, 202 struct nlattr *tb[], int maxtype, 203 const struct nla_policy *policy, 204 struct netlink_ext_ack *extack) 205 { 206 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 207 policy, NL_VALIDATE_STRICT, extack); 208 } 209 210 /** 211 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 212 * @cb: netlink callback structure that stores the sequence number 213 * @user_hdr: user header as returned from genlmsg_put() 214 * 215 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 216 * simpler to use with generic netlink. 217 */ 218 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 219 void *user_hdr) 220 { 221 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr)); 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 const 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 void genlmsg_end(struct sk_buff *skb, void *hdr) 249 { 250 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(const 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(const 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(const 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(const struct genl_family *family, 394 struct net *net, u32 portid, 395 u32 group, int code) 396 { 397 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 398 return -EINVAL; 399 group = family->mcgrp_offset + group; 400 return netlink_set_err(net->genl_sock, portid, group, code); 401 } 402 403 static inline int genl_has_listeners(const struct genl_family *family, 404 struct net *net, unsigned int group) 405 { 406 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 407 return -EINVAL; 408 group = family->mcgrp_offset + group; 409 return netlink_has_listeners(net->genl_sock, group); 410 } 411 #endif /* __NET_GENERIC_NETLINK_H */ 412