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 /**
   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 */