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 identifier (private) 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 (private) 43 * @mcgrps: multicast groups used by this family 44 * @n_mcgrps: number of multicast groups 45 * @mcgrp_offset: starting number of multicast group IDs in this family 46 * (private) 47 * @ops: the operations supported by this family 48 * @n_ops: number of operations supported by this family 49 */ 50 struct genl_family { 51 int id; /* private */ 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; 68 const struct genl_multicast_group *mcgrps; 69 unsigned int n_ops; 70 unsigned int n_mcgrps; 71 unsigned int mcgrp_offset; /* private */ 72 struct module *module; 73 }; 74 75 struct nlattr **genl_family_attrbuf(const struct genl_family *family); 76 77 /** 78 * struct genl_info - receiving information 79 * @snd_seq: sending sequence number 80 * @snd_portid: netlink portid of sender 81 * @nlhdr: netlink message header 82 * @genlhdr: generic netlink message header 83 * @userhdr: user specific header 84 * @attrs: netlink attributes 85 * @_net: network namespace 86 * @user_ptr: user pointers 87 */ 88 struct 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 }; 98 99 static inline struct net *genl_info_net(struct genl_info *info) 100 { 101 return read_pnet(&info->_net); 102 } 103 104 static inline void genl_info_net_set(struct genl_info *info, struct net *net) 105 { 106 write_pnet(&info->_net, net); 107 } 108 109 /** 110 * struct genl_ops - generic netlink operations 111 * @cmd: command identifier 112 * @internal_flags: flags used by the family 113 * @flags: flags 114 * @policy: attribute validation policy 115 * @doit: standard command callback 116 * @start: start callback for dumps 117 * @dumpit: callback for dumpers 118 * @done: completion callback for dumps 119 * @ops_list: operations list 120 */ 121 struct genl_ops { 122 const struct nla_policy *policy; 123 int (*doit)(struct sk_buff *skb, 124 struct genl_info *info); 125 int (*start)(struct netlink_callback *cb); 126 int (*dumpit)(struct sk_buff *skb, 127 struct netlink_callback *cb); 128 int (*done)(struct netlink_callback *cb); 129 u8 cmd; 130 u8 internal_flags; 131 u8 flags; 132 }; 133 134 int genl_register_family(struct genl_family *family); 135 int genl_unregister_family(const struct genl_family *family); 136 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 137 struct genl_info *info, u32 group, gfp_t flags); 138 139 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 140 const struct genl_family *family, int flags, u8 cmd); 141 142 /** 143 * genlmsg_nlhdr - Obtain netlink header from user specified header 144 * @user_hdr: user header as returned from genlmsg_put() 145 * @family: generic netlink family 146 * 147 * Returns pointer to netlink header. 148 */ 149 static inline struct nlmsghdr * 150 genlmsg_nlhdr(void *user_hdr, const struct genl_family *family) 151 { 152 return (struct nlmsghdr *)((char *)user_hdr - 153 family->hdrsize - 154 GENL_HDRLEN - 155 NLMSG_HDRLEN); 156 } 157 158 /** 159 * genlmsg_parse - parse attributes of a genetlink message 160 * @nlh: netlink message header 161 * @family: genetlink message family 162 * @tb: destination array with maxtype+1 elements 163 * @maxtype: maximum attribute type to be expected 164 * @policy: validation policy 165 * */ 166 static inline int genlmsg_parse(const struct nlmsghdr *nlh, 167 const struct genl_family *family, 168 struct nlattr *tb[], int maxtype, 169 const struct nla_policy *policy) 170 { 171 return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, 172 policy); 173 } 174 175 /** 176 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 177 * @cb: netlink callback structure that stores the sequence number 178 * @user_hdr: user header as returned from genlmsg_put() 179 * @family: generic netlink family 180 * 181 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 182 * simpler to use with generic netlink. 183 */ 184 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 185 void *user_hdr, 186 const struct genl_family *family) 187 { 188 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family)); 189 } 190 191 /** 192 * genlmsg_put_reply - Add generic netlink header to a reply message 193 * @skb: socket buffer holding the message 194 * @info: receiver info 195 * @family: generic netlink family 196 * @flags: netlink message flags 197 * @cmd: generic netlink command 198 * 199 * Returns pointer to user specific header 200 */ 201 static inline void *genlmsg_put_reply(struct sk_buff *skb, 202 struct genl_info *info, 203 const struct genl_family *family, 204 int flags, u8 cmd) 205 { 206 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family, 207 flags, cmd); 208 } 209 210 /** 211 * genlmsg_end - Finalize a generic netlink message 212 * @skb: socket buffer the message is stored in 213 * @hdr: user specific header 214 */ 215 static inline void genlmsg_end(struct sk_buff *skb, void *hdr) 216 { 217 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 218 } 219 220 /** 221 * genlmsg_cancel - Cancel construction of a generic netlink message 222 * @skb: socket buffer the message is stored in 223 * @hdr: generic netlink message header 224 */ 225 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 226 { 227 if (hdr) 228 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 229 } 230 231 /** 232 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 233 * @family: the generic netlink family 234 * @net: the net namespace 235 * @skb: netlink message as socket buffer 236 * @portid: own netlink portid to avoid sending to yourself 237 * @group: offset of multicast group in groups array 238 * @flags: allocation flags 239 */ 240 static inline int genlmsg_multicast_netns(const struct genl_family *family, 241 struct net *net, struct sk_buff *skb, 242 u32 portid, unsigned int group, gfp_t flags) 243 { 244 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 245 return -EINVAL; 246 group = family->mcgrp_offset + group; 247 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags); 248 } 249 250 /** 251 * genlmsg_multicast - multicast a netlink message to the default netns 252 * @family: the generic netlink family 253 * @skb: netlink message as socket buffer 254 * @portid: own netlink portid to avoid sending to yourself 255 * @group: offset of multicast group in groups array 256 * @flags: allocation flags 257 */ 258 static inline int genlmsg_multicast(const struct genl_family *family, 259 struct sk_buff *skb, u32 portid, 260 unsigned int group, gfp_t flags) 261 { 262 return genlmsg_multicast_netns(family, &init_net, skb, 263 portid, group, flags); 264 } 265 266 /** 267 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 268 * @family: the generic netlink family 269 * @skb: netlink message as socket buffer 270 * @portid: own netlink portid to avoid sending to yourself 271 * @group: offset of multicast group in groups array 272 * @flags: allocation flags 273 * 274 * This function must hold the RTNL or rcu_read_lock(). 275 */ 276 int genlmsg_multicast_allns(const struct genl_family *family, 277 struct sk_buff *skb, u32 portid, 278 unsigned int group, gfp_t flags); 279 280 /** 281 * genlmsg_unicast - unicast a netlink message 282 * @skb: netlink message as socket buffer 283 * @portid: netlink portid of the destination socket 284 */ 285 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid) 286 { 287 return nlmsg_unicast(net->genl_sock, skb, portid); 288 } 289 290 /** 291 * genlmsg_reply - reply to a request 292 * @skb: netlink message to be sent back 293 * @info: receiver information 294 */ 295 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 296 { 297 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid); 298 } 299 300 /** 301 * gennlmsg_data - head of message payload 302 * @gnlh: genetlink message header 303 */ 304 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 305 { 306 return ((unsigned char *) gnlh + GENL_HDRLEN); 307 } 308 309 /** 310 * genlmsg_len - length of message payload 311 * @gnlh: genetlink message header 312 */ 313 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 314 { 315 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 316 NLMSG_HDRLEN); 317 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 318 } 319 320 /** 321 * genlmsg_msg_size - length of genetlink message not including padding 322 * @payload: length of message payload 323 */ 324 static inline int genlmsg_msg_size(int payload) 325 { 326 return GENL_HDRLEN + payload; 327 } 328 329 /** 330 * genlmsg_total_size - length of genetlink message including padding 331 * @payload: length of message payload 332 */ 333 static inline int genlmsg_total_size(int payload) 334 { 335 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 336 } 337 338 /** 339 * genlmsg_new - Allocate a new generic netlink message 340 * @payload: size of the message payload 341 * @flags: the type of memory to allocate. 342 */ 343 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 344 { 345 return nlmsg_new(genlmsg_total_size(payload), flags); 346 } 347 348 /** 349 * genl_set_err - report error to genetlink broadcast listeners 350 * @family: the generic netlink family 351 * @net: the network namespace to report the error to 352 * @portid: the PORTID of a process that we want to skip (if any) 353 * @group: the broadcast group that will notice the error 354 * (this is the offset of the multicast group in the groups array) 355 * @code: error code, must be negative (as usual in kernelspace) 356 * 357 * This function returns the number of broadcast listeners that have set the 358 * NETLINK_RECV_NO_ENOBUFS socket option. 359 */ 360 static inline int genl_set_err(const struct genl_family *family, 361 struct net *net, u32 portid, 362 u32 group, int code) 363 { 364 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 365 return -EINVAL; 366 group = family->mcgrp_offset + group; 367 return netlink_set_err(net->genl_sock, portid, group, code); 368 } 369 370 static inline int genl_has_listeners(const struct genl_family *family, 371 struct net *net, unsigned int group) 372 { 373 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 374 return -EINVAL; 375 group = family->mcgrp_offset + group; 376 return netlink_has_listeners(net->genl_sock, group); 377 } 378 #endif /* __NET_GENERIC_NETLINK_H */ 379