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