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