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 };
  65
  66 /**
  67  * struct genl_info - receiving information
  68  * @snd_seq: sending sequence number
  69  * @snd_portid: netlink portid of sender
  70  * @nlhdr: netlink message header
  71  * @genlhdr: generic netlink message header
  72  * @userhdr: user specific header
  73  * @attrs: netlink attributes
  74  * @_net: network namespace
  75  * @user_ptr: user pointers
  76  */
  77 struct genl_info {
  78         u32                     snd_seq;
  79         u32                     snd_portid;
  80         struct nlmsghdr *       nlhdr;
  81         struct genlmsghdr *     genlhdr;
  82         void *                  userhdr;
  83         struct nlattr **        attrs;
  84 #ifdef CONFIG_NET_NS
  85         struct net *            _net;
  86 #endif
  87         void *                  user_ptr[2];
  88 };
  89
  90 static inline struct net *genl_info_net(struct genl_info *info)
  91 {
  92         return read_pnet(&info->_net);
  93 }
  94
  95 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  96 {
  97         write_pnet(&info->_net, net);
  98 }
  99
 100 /**
 101  * struct genl_ops - generic netlink operations
 102  * @cmd: command identifier
 103  * @internal_flags: flags used by the family
 104  * @flags: flags
 105  * @policy: attribute validation policy
 106  * @doit: standard command callback
 107  * @dumpit: callback for dumpers
 108  * @done: completion callback for dumps
 109  * @ops_list: operations list
 110  */
 111 struct genl_ops {
 112         u8                      cmd;
 113         u8                      internal_flags;
 114         unsigned int            flags;
 115         const struct nla_policy *policy;
 116         int                    (*doit)(struct sk_buff *skb,
 117                                        struct genl_info *info);
 118         int                    (*dumpit)(struct sk_buff *skb,
 119                                          struct netlink_callback *cb);
 120         int                    (*done)(struct netlink_callback *cb);
 121         struct list_head        ops_list;
 122 };
 123
 124 extern int genl_register_family(struct genl_family *family);
 125 extern int genl_register_family_with_ops(struct genl_family *family,
 126         struct genl_ops *ops, size_t n_ops);
 127 extern int genl_unregister_family(struct genl_family *family);
 128 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
 129 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
 130 extern int genl_register_mc_group(struct genl_family *family,
 131                                   struct genl_multicast_group *grp);
 132 extern void genl_unregister_mc_group(struct genl_family *family,
 133                                      struct genl_multicast_group *grp);
 134 extern void genl_notify(struct sk_buff *skb, struct net *net, u32 portid,
 135                         u32 group, struct nlmsghdr *nlh, gfp_t flags);
 136
 137 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 138                                 struct genl_family *family, int flags, u8 cmd);
 139
 140 /**
 141  * genlmsg_nlhdr - Obtain netlink header from user specified header
 142  * @user_hdr: user header as returned from genlmsg_put()
 143  * @family: generic netlink family
 144  *
 145  * Returns pointer to netlink header.
 146  */
 147 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
 148                                              struct genl_family *family)
 149 {
 150         return (struct nlmsghdr *)((char *)user_hdr -
 151                                    family->hdrsize -
 152                                    GENL_HDRLEN -
 153                                    NLMSG_HDRLEN);
 154 }
 155
 156 /**
 157  * genl_dump_check_consistent - check if sequence is consistent and advertise if not
 158  * @cb: netlink callback structure that stores the sequence number
 159  * @user_hdr: user header as returned from genlmsg_put()
 160  * @family: generic netlink family
 161  *
 162  * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
 163  * simpler to use with generic netlink.
 164  */
 165 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
 166                                               void *user_hdr,
 167                                               struct genl_family *family)
 168 {
 169         nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
 170 }
 171
 172 /**
 173  * genlmsg_put_reply - Add generic netlink header to a reply message
 174  * @skb: socket buffer holding the message
 175  * @info: receiver info
 176  * @family: generic netlink family
 177  * @flags: netlink message flags
 178  * @cmd: generic netlink command
 179  *
 180  * Returns pointer to user specific header
 181  */
 182 static inline void *genlmsg_put_reply(struct sk_buff *skb,
 183                                       struct genl_info *info,
 184                                       struct genl_family *family,
 185                                       int flags, u8 cmd)
 186 {
 187         return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
 188                            flags, cmd);
 189 }
 190
 191 /**
 192  * genlmsg_end - Finalize a generic netlink message
 193  * @skb: socket buffer the message is stored in
 194  * @hdr: user specific header
 195  */
 196 static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
 197 {
 198         return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 199 }
 200
 201 /**
 202  * genlmsg_cancel - Cancel construction of a generic netlink message
 203  * @skb: socket buffer the message is stored in
 204  * @hdr: generic netlink message header
 205  */
 206 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 207 {
 208         if (hdr)
 209                 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 210 }
 211
 212 /**
 213  * genlmsg_multicast_netns - multicast a netlink message to a specific netns
 214  * @net: the net namespace
 215  * @skb: netlink message as socket buffer
 216  * @portid: own netlink portid to avoid sending to yourself
 217  * @group: multicast group id
 218  * @flags: allocation flags
 219  */
 220 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
 221                                           u32 portid, unsigned int group, gfp_t flags)
 222 {
 223         return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
 224 }
 225
 226 /**
 227  * genlmsg_multicast - multicast a netlink message to the default netns
 228  * @skb: netlink message as socket buffer
 229  * @portid: own netlink portid to avoid sending to yourself
 230  * @group: multicast group id
 231  * @flags: allocation flags
 232  */
 233 static inline int genlmsg_multicast(struct sk_buff *skb, u32 portid,
 234                                     unsigned int group, gfp_t flags)
 235 {
 236         return genlmsg_multicast_netns(&init_net, skb, portid, group, flags);
 237 }
 238
 239 /**
 240  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
 241  * @skb: netlink message as socket buffer
 242  * @portid: own netlink portid to avoid sending to yourself
 243  * @group: multicast group id
 244  * @flags: allocation flags
 245  *
 246  * This function must hold the RTNL or rcu_read_lock().
 247  */
 248 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid,
 249                             unsigned int group, gfp_t flags);
 250
 251 /**
 252  * genlmsg_unicast - unicast a netlink message
 253  * @skb: netlink message as socket buffer
 254  * @portid: netlink portid of the destination socket
 255  */
 256 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
 257 {
 258         return nlmsg_unicast(net->genl_sock, skb, portid);
 259 }
 260
 261 /**
 262  * genlmsg_reply - reply to a request
 263  * @skb: netlink message to be sent back
 264  * @info: receiver information
 265  */
 266 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
 267 {
 268         return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
 269 }
 270
 271 /**
 272  * gennlmsg_data - head of message payload
 273  * @gnlh: genetlink message header
 274  */
 275 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
 276 {
 277         return ((unsigned char *) gnlh + GENL_HDRLEN);
 278 }
 279
 280 /**
 281  * genlmsg_len - length of message payload
 282  * @gnlh: genetlink message header
 283  */
 284 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
 285 {
 286         struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
 287                                                         NLMSG_HDRLEN);
 288         return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
 289 }
 290
 291 /**
 292  * genlmsg_msg_size - length of genetlink message not including padding
 293  * @payload: length of message payload
 294  */
 295 static inline int genlmsg_msg_size(int payload)
 296 {
 297         return GENL_HDRLEN + payload;
 298 }
 299
 300 /**
 301  * genlmsg_total_size - length of genetlink message including padding
 302  * @payload: length of message payload
 303  */
 304 static inline int genlmsg_total_size(int payload)
 305 {
 306         return NLMSG_ALIGN(genlmsg_msg_size(payload));
 307 }
 308
 309 /**
 310  * genlmsg_new - Allocate a new generic netlink message
 311  * @payload: size of the message payload
 312  * @flags: the type of memory to allocate.
 313  */
 314 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
 315 {
 316         return nlmsg_new(genlmsg_total_size(payload), flags);
 317 }
 318
 319
 320 #endif  /* __NET_GENERIC_NETLINK_H */