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 extern void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, 132 u32 group, struct nlmsghdr *nlh, gfp_t flags); 133 134 /** 135 * genlmsg_put - Add generic netlink header to netlink message 136 * @skb: socket buffer holding the message 137 * @pid: netlink pid the message is addressed to 138 * @seq: sequence number (usually the one of the sender) 139 * @family: generic netlink family 140 * @flags netlink message flags 141 * @cmd: generic netlink command 142 * 143 * Returns pointer to user specific header 144 */ 145 static inline void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, 146 struct genl_family *family, int flags, u8 cmd) 147 { 148 struct nlmsghdr *nlh; 149 struct genlmsghdr *hdr; 150 151 nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN + 152 family->hdrsize, flags); 153 if (nlh == NULL) 154 return NULL; 155 156 hdr = nlmsg_data(nlh); 157 hdr->cmd = cmd; 158 hdr->version = family->version; 159 hdr->reserved = 0; 160 161 return (char *) hdr + GENL_HDRLEN; 162 } 163 164 /** 165 * genlmsg_nlhdr - Obtain netlink header from user specified header 166 * @user_hdr: user header as returned from genlmsg_put() 167 * @family: generic netlink family 168 * 169 * Returns pointer to netlink header. 170 */ 171 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr, 172 struct genl_family *family) 173 { 174 return (struct nlmsghdr *)((char *)user_hdr - 175 family->hdrsize - 176 GENL_HDRLEN - 177 NLMSG_HDRLEN); 178 } 179 180 /** 181 * genl_dump_check_consistent - check if sequence is consistent and advertise if not 182 * @cb: netlink callback structure that stores the sequence number 183 * @user_hdr: user header as returned from genlmsg_put() 184 * @family: generic netlink family 185 * 186 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it 187 * simpler to use with generic netlink. 188 */ 189 static inline void genl_dump_check_consistent(struct netlink_callback *cb, 190 void *user_hdr, 191 struct genl_family *family) 192 { 193 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family)); 194 } 195 196 /** 197 * genlmsg_put_reply - Add generic netlink header to a reply message 198 * @skb: socket buffer holding the message 199 * @info: receiver info 200 * @family: generic netlink family 201 * @flags: netlink message flags 202 * @cmd: generic netlink command 203 * 204 * Returns pointer to user specific header 205 */ 206 static inline void *genlmsg_put_reply(struct sk_buff *skb, 207 struct genl_info *info, 208 struct genl_family *family, 209 int flags, u8 cmd) 210 { 211 return genlmsg_put(skb, info->snd_pid, info->snd_seq, family, 212 flags, cmd); 213 } 214 215 /** 216 * genlmsg_end - Finalize a generic netlink message 217 * @skb: socket buffer the message is stored in 218 * @hdr: user specific header 219 */ 220 static inline int genlmsg_end(struct sk_buff *skb, void *hdr) 221 { 222 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 223 } 224 225 /** 226 * genlmsg_cancel - Cancel construction of a generic netlink message 227 * @skb: socket buffer the message is stored in 228 * @hdr: generic netlink message header 229 */ 230 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 231 { 232 if (hdr) 233 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); 234 } 235 236 /** 237 * genlmsg_multicast_netns - multicast a netlink message to a specific netns 238 * @net: the net namespace 239 * @skb: netlink message as socket buffer 240 * @pid: own netlink pid to avoid sending to yourself 241 * @group: multicast group id 242 * @flags: allocation flags 243 */ 244 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb, 245 u32 pid, unsigned int group, gfp_t flags) 246 { 247 return nlmsg_multicast(net->genl_sock, skb, pid, group, flags); 248 } 249 250 /** 251 * genlmsg_multicast - multicast a netlink message to the default netns 252 * @skb: netlink message as socket buffer 253 * @pid: own netlink pid to avoid sending to yourself 254 * @group: multicast group id 255 * @flags: allocation flags 256 */ 257 static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid, 258 unsigned int group, gfp_t flags) 259 { 260 return genlmsg_multicast_netns(&init_net, skb, pid, group, flags); 261 } 262 263 /** 264 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces 265 * @skb: netlink message as socket buffer 266 * @pid: own netlink pid to avoid sending to yourself 267 * @group: multicast group id 268 * @flags: allocation flags 269 * 270 * This function must hold the RTNL or rcu_read_lock(). 271 */ 272 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, 273 unsigned int group, gfp_t flags); 274 275 /** 276 * genlmsg_unicast - unicast a netlink message 277 * @skb: netlink message as socket buffer 278 * @pid: netlink pid of the destination socket 279 */ 280 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid) 281 { 282 return nlmsg_unicast(net->genl_sock, skb, pid); 283 } 284 285 /** 286 * genlmsg_reply - reply to a request 287 * @skb: netlink message to be sent back 288 * @info: receiver information 289 */ 290 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) 291 { 292 return genlmsg_unicast(genl_info_net(info), skb, info->snd_pid); 293 } 294 295 /** 296 * gennlmsg_data - head of message payload 297 * @gnlh: genetlink message header 298 */ 299 static inline void *genlmsg_data(const struct genlmsghdr *gnlh) 300 { 301 return ((unsigned char *) gnlh + GENL_HDRLEN); 302 } 303 304 /** 305 * genlmsg_len - length of message payload 306 * @gnlh: genetlink message header 307 */ 308 static inline int genlmsg_len(const struct genlmsghdr *gnlh) 309 { 310 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - 311 NLMSG_HDRLEN); 312 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); 313 } 314 315 /** 316 * genlmsg_msg_size - length of genetlink message not including padding 317 * @payload: length of message payload 318 */ 319 static inline int genlmsg_msg_size(int payload) 320 { 321 return GENL_HDRLEN + payload; 322 } 323 324 /** 325 * genlmsg_total_size - length of genetlink message including padding 326 * @payload: length of message payload 327 */ 328 static inline int genlmsg_total_size(int payload) 329 { 330 return NLMSG_ALIGN(genlmsg_msg_size(payload)); 331 } 332 333 /** 334 * genlmsg_new - Allocate a new generic netlink message 335 * @payload: size of the message payload 336 * @flags: the type of memory to allocate. 337 */ 338 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 339 { 340 return nlmsg_new(genlmsg_total_size(payload), flags); 341 } 342 343 344 #endif /* __NET_GENERIC_NETLINK_H */ 345