include/net/genetlink.h

   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  * @id: multicast group ID, assigned by the core, to use with
  14  *      genlmsg_multicast().
  15  * @list: list entry for linking
  16  */
  17 struct genl_multicast_group {
  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  * @family_list: family list
  41  * @mcast_groups: multicast groups list
  42  * @ops: the operations supported by this family (private)
  43  * @n_ops: number of operations supported by this family (private)
  44  */
  45 struct genl_family {
  46         unsigned int            id;
  47         unsigned int            hdrsize;
  48         char                    name[GENL_NAMSIZ];
  49         unsigned int            version;
  50         unsigned int            maxattr;
  51         bool                    netnsok;
  52         bool                    parallel_ops;
  53         int                     (*pre_doit)(const struct genl_ops *ops,
  54                                             struct sk_buff *skb,
  55                                             struct genl_info *info);
  56         void                    (*post_doit)(const struct genl_ops *ops,
  57                                              struct sk_buff *skb,
  58                                              struct genl_info *info);
  59         struct nlattr **        attrbuf;        /* private */
  60         const struct genl_ops * ops;            /* private */
  61         unsigned int            n_ops;          /* private */
  62         struct list_head        family_list;    /* private */
  63         struct list_head        mcast_groups;   /* private */
  64         struct module           *module;
  65 };
  66
  67 /**
  68  * struct genl_info - receiving information
  69  * @snd_seq: sending sequence number
  70  * @snd_portid: netlink portid of sender
  71  * @nlhdr: netlink message header
  72  * @genlhdr: generic netlink message header
  73  * @userhdr: user specific header
  74  * @attrs: netlink attributes
  75  * @_net: network namespace
  76  * @user_ptr: user pointers
  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 };
  90
  91 static inline struct net *genl_info_net(struct genl_info *info)
  92 {
  93         return read_pnet(&info->_net);
  94 }
  95
  96 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  97 {
  98         write_pnet(&info->_net, net);
  99 }
 100
 101 /**
 102  * struct genl_ops - generic netlink operations
 103  * @cmd: command identifier
 104  * @internal_flags: flags used by the family
 105  * @flags: flags
 106  * @policy: attribute validation policy
 107  * @doit: standard command callback
 108  * @dumpit: callback for dumpers
 109  * @done: completion callback for dumps
 110  * @ops_list: operations list
 111  */
 112 struct genl_ops {
 113         const struct nla_policy *policy;
 114         int                    (*doit)(struct sk_buff *skb,
 115                                        struct genl_info *info);
 116         int                    (*dumpit)(struct sk_buff *skb,
 117                                          struct netlink_callback *cb);
 118         int                    (*done)(struct netlink_callback *cb);
 119         u8                      cmd;
 120         u8                      internal_flags;
 121         u8                      flags;
 122 };
 123
 124 int __genl_register_family(struct genl_family *family);
 125
 126 static inline int genl_register_family(struct genl_family *family)
 127 {
 128         family->module = THIS_MODULE;
 129         return __genl_register_family(family);
 130 }
 131
 132 /**
 133  * genl_register_family_with_ops - register a generic netlink family with ops
 134  * @family: generic netlink family
 135  * @ops: operations to be registered
 136  * @n_ops: number of elements to register
 137  *
 138  * Registers the specified family and operations from the specified table.
 139  * Only one family may be registered with the same family name or identifier.
 140  *
 141  * The family id may equal GENL_ID_GENERATE causing an unique id to
 142  * be automatically generated and assigned.
 143  *
 144  * Either a doit or dumpit callback must be specified for every registered
 145  * operation or the function will fail. Only one operation structure per
 146  * command identifier may be registered.
 147  *
 148  * See include/net/genetlink.h for more documenation on the operations
 149  * structure.
 150  *
 151  * Return 0 on success or a negative error code.
 152  */
 153 static inline int _genl_register_family_with_ops(struct genl_family *family,
 154                                                  const struct genl_ops *ops,
 155                                                  size_t n_ops)
 156 {
 157         family->module = THIS_MODULE;
 158         family->ops = ops;
 159         family->n_ops = n_ops;
 160         return __genl_register_family(family);
 161 }
 162
 163 #define genl_register_family_with_ops(family, ops)      \
 164         _genl_register_family_with_ops((family), (ops), ARRAY_SIZE(ops))
 165
 166 int genl_unregister_family(struct genl_family *family);
 167 int genl_register_mc_group(struct genl_family *family,
 168                            struct genl_multicast_group *grp);
 169 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid,
 170                  u32 group, struct nlmsghdr *nlh, gfp_t flags);
 171
 172 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 173                   struct genl_family *family, int flags, u8 cmd);
 174
 175 /**
 176  * genlmsg_nlhdr - Obtain netlink header from user specified header
 177  * @user_hdr: user header as returned from genlmsg_put()
 178  * @family: generic netlink family
 179  *
 180  * Returns pointer to netlink header.
 181  */
 182 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
 183                                              struct genl_family *family)
 184 {
 185         return (struct nlmsghdr *)((char *)user_hdr -
 186                                    family->hdrsize -
 187                                    GENL_HDRLEN -
 188                                    NLMSG_HDRLEN);
 189 }
 190
 191 /**
 192  * genl_dump_check_consistent - check if sequence is consistent and advertise if not
 193  * @cb: netlink callback structure that stores the sequence number
 194  * @user_hdr: user header as returned from genlmsg_put()
 195  * @family: generic netlink family
 196  *
 197  * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
 198  * simpler to use with generic netlink.
 199  */
 200 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
 201                                               void *user_hdr,
 202                                               struct genl_family *family)
 203 {
 204         nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
 205 }
 206
 207 /**
 208  * genlmsg_put_reply - Add generic netlink header to a reply message
 209  * @skb: socket buffer holding the message
 210  * @info: receiver info
 211  * @family: generic netlink family
 212  * @flags: netlink message flags
 213  * @cmd: generic netlink command
 214  *
 215  * Returns pointer to user specific header
 216  */
 217 static inline void *genlmsg_put_reply(struct sk_buff *skb,
 218                                       struct genl_info *info,
 219                                       struct genl_family *family,
 220                                       int flags, u8 cmd)
 221 {
 222         return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
 223                            flags, cmd);
 224 }
 225
 226 /**
 227  * genlmsg_end - Finalize a generic netlink message
 228  * @skb: socket buffer the message is stored in
 229  * @hdr: user specific header
 230  */
 231 static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
 232 {
 233         return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 234 }
 235
 236 /**
 237  * genlmsg_cancel - Cancel construction of a generic netlink message
 238  * @skb: socket buffer the message is stored in
 239  * @hdr: generic netlink message header
 240  */
 241 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 242 {
 243         if (hdr)
 244                 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 245 }
 246
 247 /**
 248  * genlmsg_multicast_netns - multicast a netlink message to a specific netns
 249  * @net: the net namespace
 250  * @skb: netlink message as socket buffer
 251  * @portid: own netlink portid to avoid sending to yourself
 252  * @group: multicast group id
 253  * @flags: allocation flags
 254  */
 255 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
 256                                           u32 portid, unsigned int group, gfp_t flags)
 257 {
 258         return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
 259 }
 260
 261 /**
 262  * genlmsg_multicast - multicast a netlink message to the default netns
 263  * @skb: netlink message as socket buffer
 264  * @portid: own netlink portid to avoid sending to yourself
 265  * @group: multicast group id
 266  * @flags: allocation flags
 267  */
 268 static inline int genlmsg_multicast(struct sk_buff *skb, u32 portid,
 269                                     unsigned int group, gfp_t flags)
 270 {
 271         return genlmsg_multicast_netns(&init_net, skb, portid, group, flags);
 272 }
 273
 274 /**
 275  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
 276  * @skb: netlink message as socket buffer
 277  * @portid: own netlink portid to avoid sending to yourself
 278  * @group: multicast group id
 279  * @flags: allocation flags
 280  *
 281  * This function must hold the RTNL or rcu_read_lock().
 282  */
 283 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid,
 284                             unsigned int group, gfp_t flags);
 285
 286 /**
 287  * genlmsg_unicast - unicast a netlink message
 288  * @skb: netlink message as socket buffer
 289  * @portid: netlink portid of the destination socket
 290  */
 291 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
 292 {
 293         return nlmsg_unicast(net->genl_sock, skb, portid);
 294 }
 295
 296 /**
 297  * genlmsg_reply - reply to a request
 298  * @skb: netlink message to be sent back
 299  * @info: receiver information
 300  */
 301 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
 302 {
 303         return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
 304 }
 305
 306 /**
 307  * gennlmsg_data - head of message payload
 308  * @gnlh: genetlink message header
 309  */
 310 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
 311 {
 312         return ((unsigned char *) gnlh + GENL_HDRLEN);
 313 }
 314
 315 /**
 316  * genlmsg_len - length of message payload
 317  * @gnlh: genetlink message header
 318  */
 319 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
 320 {
 321         struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
 322                                                         NLMSG_HDRLEN);
 323         return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
 324 }
 325
 326 /**
 327  * genlmsg_msg_size - length of genetlink message not including padding
 328  * @payload: length of message payload
 329  */
 330 static inline int genlmsg_msg_size(int payload)
 331 {
 332         return GENL_HDRLEN + payload;
 333 }
 334
 335 /**
 336  * genlmsg_total_size - length of genetlink message including padding
 337  * @payload: length of message payload
 338  */
 339 static inline int genlmsg_total_size(int payload)
 340 {
 341         return NLMSG_ALIGN(genlmsg_msg_size(payload));
 342 }
 343
 344 /**
 345  * genlmsg_new - Allocate a new generic netlink message
 346  * @payload: size of the message payload
 347  * @flags: the type of memory to allocate.
 348  */
 349 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
 350 {
 351         return nlmsg_new(genlmsg_total_size(payload), flags);
 352 }
 353
 354
 355 #endif  /* __NET_GENERIC_NETLINK_H */