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