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 /** 9 * struct genl_multicast_group - generic netlink multicast group 10 * @name: name of the multicast group, names are per-family 11 * @id: multicast group ID, assigned by the core, to use with 12 * genlmsg_multicast(). 13 * @list: list entry for linking 14 * @family: pointer to family, need not be set before registering 15 */ 16 struct genl_multicast_group { 17 struct genl_family *family; /* private */ 18 struct list_head list; /* private */ 19 char name[GENL_NAMSIZ]; 20 u32 id; 21 }; 22 23 struct genl_ops; 24 struct genl_info; 25 26 /** 27 * struct genl_family - generic netlink family 28 * @id: protocol family idenfitier 29 * @hdrsize: length of user specific header in bytes 30 * @name: name of family 31 * @version: protocol version 32 * @maxattr: maximum number of attributes supported 33 * @netnsok: set to true if the family can handle network 34 * namespaces and should be presented in all of them 35 * @pre_doit: called before an operation's doit callback, it may 36 * do additional, common, filtering and return an error 37 * @post_doit: called after an operation's doit callback, it may 38 * undo operations done by pre_doit, for example release locks 39 * @attrbuf: buffer to store parsed attributes 40 * @ops_list: list of all assigned operations 41 * @family_list: family list 42 * @mcast_groups: multicast groups list 43 */ 44 struct genl_family { 45 unsigned int id; 46 unsigned int hdrsize; 47 char name[GENL_NAMSIZ]; 48 unsigned int version; 49 unsigned int maxattr; 50 bool netnsok; 51 int (*pre_doit)(struct genl_ops *ops, 52 struct sk_buff *skb, 53 struct genl_info *info); 54 void (*post_doit)(struct genl_ops *ops, 55 struct sk_buff *skb, 56 struct genl_info *info); 57 struct nlattr ** attrbuf; /* private */ 58 struct list_head ops_list; /* private */ 59 struct list_head family_list; /* private */ 60 struct list_head mcast_groups; /* private */ 61 }; 62 63 /** 64 * struct genl_info - receiving information 65 * @snd_seq: sending sequence number 66 * @snd_pid: netlink pid of sender 67 * @nlhdr: netlink message header 68 * @genlhdr: generic netlink message header 69 * @userhdr: user specific header 70 * @attrs: netlink attributes 71 * @_net: network namespace 72 * @user_ptr: user pointers 73 */ 74 struct genl_info { 75 u32 snd_seq; 76 u32 snd_pid; 77 struct nlmsghdr * nlhdr; 78 struct genlmsghdr * genlhdr; 79 void * userhdr; 80 struct nlattr ** attrs; 81 #ifdef CONFIG_NET_NS 82 struct net * _net; 83 #endif 84 void * user_ptr[2]; 85 }; 86 87 static inline struct net *genl_info_net(struct genl_info *info) 88 { 89 return read_pnet(&info->_net); 90 } 91 92 static inline void genl_info_net_set(struct genl_info *info, struct net *net) 93 { 94 write_pnet(&info->_net, net); 95 } 96 97 /** 98 * struct genl_ops - generic netlink operations 99 * @cmd: command identifier 100 * @internal_flags: flags used by the family 101 * @flags: flags 102 * @policy: attribute validation policy 103 * @doit: standard command callback 104 * @dumpit: callback for dumpers 105 * @done: completion callback for dumps 106 * @ops_list: operations list 107 */ 108 struct genl_ops { 109 u8 cmd; 110 u8 internal_flags; 111 unsigned int flags; 112 const struct nla_policy *policy; 113 int (*doit)(struct sk_buff *skb, 114 struct genl_info *info); 115 int (*dumpit)(struct sk_buff *skb, 116 struct netlink_callback *cb); 117 int (*done)(struct netlink_callback *cb); 118 struct list_head ops_list; 119 }; 120 121 extern int genl_register_family(struct genl_family *family); 122 extern int genl_register_family_with_ops(struct genl_family *family, 123 struct genl_ops *ops, size_t n_ops); 124 extern int genl_unregister_family(struct genl_family *family); 125 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops); 126 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops); 127 extern int genl_register_mc_group(struct genl_family *family, 128 struct genl_multicast_group *grp); 129 extern void genl_unregister_mc_group(struct genl_family *family, 130 struct genl_multicast_group *grp); 131 132 /** 133 * genlmsg_put - Add generic netlink header to netlink message 134 * @skb: socket buffer holding the message 135 * @pid: netlink pid the message is addressed to 136 * @seq: sequence number (usually the one of the sender) 137 * @family: generic netlink family 138 * @flags netlink message flags 139 * @cmd: generic netlink command 140 * 141 * Returns pointer to user specific header 142 */ 143 static inline void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, 144 struct genl_family *family, int flags, u8 cmd) 145 { 146 struct nlmsghdr *nlh; 147 struct genlmsghdr *hdr; 148 149 nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN + 150 family->hdrsize, flags); 151 if (nlh == NULL) 152 return NULL; 153 154 hdr = nlmsg_data(nlh); 155 hdr->cmd = cmd; 156 hdr->version = family->version; 157 hdr->reserved = 0; 158 159 return (char *) hdr + GENL_HDRLEN; 160 } 161 162 /** 163 * genlmsg_nlhdr - Obtain netlink header from user specified header 164 * @user_hdr: user header as returned from genlmsg_put() 165 * @family: generic netlink family 166 * 167 * Returns pointer to netlink header. 168 */ 169 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr, 170 struct genl_family *family) 171 { 172 return (struct nlmsghdr *)((char *)user_hdr - 173 family->hdrsize - 174 GENL_HDRLEN - 175 NLMSG_HDRLEN); 176 } 177 178 /** 179 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 180 * @cb: netlink callback structure that stores the sequence number 181 * @user_hdr: user header as returned from genlmsg_put() 182 * @family: generic netlink family 183 * 184 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 185 * simpler to use with generic netlink. 186 */ 187 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 188 void *user_hdr, 189 struct genl_family *family) 190 { 191 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family)); 192 } 193 194 /** 195 * genlmsg_put_reply - Add generic netlink header to a reply message 196 * @skb: socket buffer holding the message 197 * @info: receiver info 198 * @family: generic netlink family 199 * @flags: netlink message flags 200 * @cmd: generic netlink command 201 * 202 * Returns pointer to user specific header 203 */ 204 static inline void *genlmsg_put_reply(struct sk_buff *skb, 205 struct genl_info *info, 206 struct genl_family *family, 207 int flags, u8 cmd) 208 { 209 return genlmsg_put(skb, info->snd_pid, info->snd_seq, family, 210 flags, cmd); 211 } 212 213 /** 214 * genlmsg_end - Finalize a generic netlink message 215 * @skb: socket buffer the message is stored in 216 * @hdr: user specific header 217 */ 218 static inline int genlmsg_end(struct sk_buff *skb, void *hdr) 219 { 220 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 221 } 222 223 /** 224 * genlmsg_cancel - Cancel construction of a generic netlink message 225 * @skb: socket buffer the message is stored in 226 * @hdr: generic netlink message header 227 */ 228 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 229 { 230 if (hdr) 231 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 232 } 233 234 /** 235 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 236 * @net: the net namespace 237 * @skb: netlink message as socket buffer 238 * @pid: own netlink pid to avoid sending to yourself 239 * @group: multicast group id 240 * @flags: allocation flags 241 */ 242 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb, 243 u32 pid, unsigned int group, gfp_t flags) 244 { 245 return nlmsg_multicast(net->genl_sock, skb, pid, group, flags); 246 } 247 248 /** 249 * genlmsg_multicast - multicast a netlink message to the default netns 250 * @skb: netlink message as socket buffer 251 * @pid: own netlink pid to avoid sending to yourself 252 * @group: multicast group id 253 * @flags: allocation flags 254 */ 255 static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid, 256 unsigned int group, gfp_t flags) 257 { 258 return genlmsg_multicast_netns(&init_net, skb, pid, group, flags); 259 } 260 261 /** 262 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 263 * @skb: netlink message as socket buffer 264 * @pid: own netlink pid to avoid sending to yourself 265 * @group: multicast group id 266 * @flags: allocation flags 267 * 268 * This function must hold the RTNL or rcu_read_lock(). 269 */ 270 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, 271 unsigned int group, gfp_t flags); 272 273 /** 274 * genlmsg_unicast - unicast a netlink message 275 * @skb: netlink message as socket buffer 276 * @pid: netlink pid of the destination socket 277 */ 278 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid) 279 { 280 return nlmsg_unicast(net->genl_sock, skb, pid); 281 } 282 283 /** 284 * genlmsg_reply - reply to a request 285 * @skb: netlink message to be sent back 286 * @info: receiver information 287 */ 288 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 289 { 290 return genlmsg_unicast(genl_info_net(info), skb, info->snd_pid); 291 } 292 293 /** 294 * gennlmsg_data - head of message payload 295 * @gnlh: genetlink message header 296 */ 297 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 298 { 299 return ((unsigned char *) gnlh + GENL_HDRLEN); 300 } 301 302 /** 303 * genlmsg_len - length of message payload 304 * @gnlh: genetlink message header 305 */ 306 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 307 { 308 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 309 NLMSG_HDRLEN); 310 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 311 } 312 313 /** 314 * genlmsg_msg_size - length of genetlink message not including padding 315 * @payload: length of message payload 316 */ 317 static inline int genlmsg_msg_size(int payload) 318 { 319 return GENL_HDRLEN + payload; 320 } 321 322 /** 323 * genlmsg_total_size - length of genetlink message including padding 324 * @payload: length of message payload 325 */ 326 static inline int genlmsg_total_size(int payload) 327 { 328 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 329 } 330 331 /** 332 * genlmsg_new - Allocate a new generic netlink message 333 * @payload: size of the message payload 334 * @flags: the type of memory to allocate. 335 */ 336 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 337 { 338 return nlmsg_new(genlmsg_total_size(payload), flags); 339 } 340 341 342 #endif /* __NET_GENERIC_NETLINK_H */ 343