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