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         int                     (*pre_doit)(struct genl_ops *ops,
  54                                             struct sk_buff *skb,
  55                                             struct genl_info *info);
  56         void                    (*post_doit)(struct genl_ops *ops,
  57                                              struct sk_buff *skb,
  58                                              struct genl_info *info);
  59         struct nlattr **        attrbuf;        /* private */
  60         struct list_head        ops_list;       /* private */
  61         struct list_head        family_list;    /* private */
  62         struct list_head        mcast_groups;   /* private */
  63 };
  64
  65 /**
  66  * struct genl_info - receiving information
  67  * @snd_seq: sending sequence number
  68  * @snd_portid: netlink portid of sender
  69  * @nlhdr: netlink message header
  70  * @genlhdr: generic netlink message header
  71  * @userhdr: user specific header
  72  * @attrs: netlink attributes
  73  * @_net: network namespace
  74  * @user_ptr: user pointers
  75  */
  76 struct genl_info {
  77         u32                     snd_seq;
  78         u32                     snd_portid;
  79         struct nlmsghdr *       nlhdr;
  80         struct genlmsghdr *     genlhdr;
  81         void *                  userhdr;
  82         struct nlattr **        attrs;
  83 #ifdef CONFIG_NET_NS
  84         struct net *            _net;
  85 #endif
  86         void *                  user_ptr[2];
  87 };
  88
  89 static inline struct net *genl_info_net(struct genl_info *info)
  90 {
  91         return read_pnet(&info->_net);
  92 }
  93
  94 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  95 {
  96         write_pnet(&info->_net, net);
  97 }
  98
  99 /**
 100  * struct genl_ops - generic netlink operations
 101  * @cmd: command identifier
 102  * @internal_flags: flags used by the family
 103  * @flags: flags
 104  * @policy: attribute validation policy
 105  * @doit: standard command callback
 106  * @dumpit: callback for dumpers
 107  * @done: completion callback for dumps
 108  * @ops_list: operations list
 109  */
 110 struct genl_ops {
 111         u8                      cmd;
 112         u8                      internal_flags;
 113         unsigned int            flags;
 114         const struct nla_policy *policy;
 115         int                    (*doit)(struct sk_buff *skb,
 116                                        struct genl_info *info);
 117         int                    (*dumpit)(struct sk_buff *skb,
 118                                          struct netlink_callback *cb);
 119         int                    (*done)(struct netlink_callback *cb);
 120         struct list_head        ops_list;
 121 };
 122
 123 extern int genl_register_family(struct genl_family *family);
 124 extern int genl_register_family_with_ops(struct genl_family *family,
 125         struct genl_ops *ops, size_t n_ops);
 126 extern int genl_unregister_family(struct genl_family *family);
 127 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
 128 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
 129 extern int genl_register_mc_group(struct genl_family *family,
 130                                   struct genl_multicast_group *grp);
 131 extern void genl_unregister_mc_group(struct genl_family *family,
 132                                      struct genl_multicast_group *grp);
 133 extern void genl_notify(struct sk_buff *skb, struct net *net, u32 portid,
 134                         u32 group, struct nlmsghdr *nlh, gfp_t flags);
 135
 136 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 137                                 struct genl_family *family, int flags, u8 cmd);
 138
 139 /**
 140  * genlmsg_nlhdr - Obtain netlink header from user specified header
 141  * @user_hdr: user header as returned from genlmsg_put()
 142  * @family: generic netlink family
 143  *
 144  * Returns pointer to netlink header.
 145  */
 146 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
 147                                              struct genl_family *family)
 148 {
 149         return (struct nlmsghdr *)((char *)user_hdr -
 150                                    family->hdrsize -
 151                                    GENL_HDRLEN -
 152                                    NLMSG_HDRLEN);
 153 }
 154
 155 /**
 156  * genl_dump_check_consistent - check if sequence is consistent and advertise if not
 157  * @cb: netlink callback structure that stores the sequence number
 158  * @user_hdr: user header as returned from genlmsg_put()
 159  * @family: generic netlink family
 160  *
 161  * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
 162  * simpler to use with generic netlink.
 163  */
 164 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
 165                                               void *user_hdr,
 166                                               struct genl_family *family)
 167 {
 168         nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
 169 }
 170
 171 /**
 172  * genlmsg_put_reply - Add generic netlink header to a reply message
 173  * @skb: socket buffer holding the message
 174  * @info: receiver info
 175  * @family: generic netlink family
 176  * @flags: netlink message flags
 177  * @cmd: generic netlink command
 178  *
 179  * Returns pointer to user specific header
 180  */
 181 static inline void *genlmsg_put_reply(struct sk_buff *skb,
 182                                       struct genl_info *info,
 183                                       struct genl_family *family,
 184                                       int flags, u8 cmd)
 185 {
 186         return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
 187                            flags, cmd);
 188 }
 189
 190 /**
 191  * genlmsg_end - Finalize a generic netlink message
 192  * @skb: socket buffer the message is stored in
 193  * @hdr: user specific header
 194  */
 195 static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
 196 {
 197         return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 198 }
 199
 200 /**
 201  * genlmsg_cancel - Cancel construction of a generic netlink message
 202  * @skb: socket buffer the message is stored in
 203  * @hdr: generic netlink message header
 204  */
 205 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 206 {
 207         if (hdr)
 208                 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 209 }
 210
 211 /**
 212  * genlmsg_multicast_netns - multicast a netlink message to a specific netns
 213  * @net: the net namespace
 214  * @skb: netlink message as socket buffer
 215  * @portid: own netlink portid to avoid sending to yourself
 216  * @group: multicast group id
 217  * @flags: allocation flags
 218  */
 219 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
 220                                           u32 portid, unsigned int group, gfp_t flags)
 221 {
 222         return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
 223 }
 224
 225 /**
 226  * genlmsg_multicast - multicast a netlink message to the default netns
 227  * @skb: netlink message as socket buffer
 228  * @portid: own netlink portid to avoid sending to yourself
 229  * @group: multicast group id
 230  * @flags: allocation flags
 231  */
 232 static inline int genlmsg_multicast(struct sk_buff *skb, u32 portid,
 233                                     unsigned int group, gfp_t flags)
 234 {
 235         return genlmsg_multicast_netns(&init_net, skb, portid, group, flags);
 236 }
 237
 238 /**
 239  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
 240  * @skb: netlink message as socket buffer
 241  * @portid: own netlink portid to avoid sending to yourself
 242  * @group: multicast group id
 243  * @flags: allocation flags
 244  *
 245  * This function must hold the RTNL or rcu_read_lock().
 246  */
 247 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid,
 248                             unsigned int group, gfp_t flags);
 249
 250 /**
 251  * genlmsg_unicast - unicast a netlink message
 252  * @skb: netlink message as socket buffer
 253  * @portid: netlink portid of the destination socket
 254  */
 255 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
 256 {
 257         return nlmsg_unicast(net->genl_sock, skb, portid);
 258 }
 259
 260 /**
 261  * genlmsg_reply - reply to a request
 262  * @skb: netlink message to be sent back
 263  * @info: receiver information
 264  */
 265 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
 266 {
 267         return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
 268 }
 269
 270 /**
 271  * gennlmsg_data - head of message payload
 272  * @gnlh: genetlink message header
 273  */
 274 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
 275 {
 276         return ((unsigned char *) gnlh + GENL_HDRLEN);
 277 }
 278
 279 /**
 280  * genlmsg_len - length of message payload
 281  * @gnlh: genetlink message header
 282  */
 283 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
 284 {
 285         struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
 286                                                         NLMSG_HDRLEN);
 287         return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
 288 }
 289
 290 /**
 291  * genlmsg_msg_size - length of genetlink message not including padding
 292  * @payload: length of message payload
 293  */
 294 static inline int genlmsg_msg_size(int payload)
 295 {
 296         return GENL_HDRLEN + payload;
 297 }
 298
 299 /**
 300  * genlmsg_total_size - length of genetlink message including padding
 301  * @payload: length of message payload
 302  */
 303 static inline int genlmsg_total_size(int payload)
 304 {
 305         return NLMSG_ALIGN(genlmsg_msg_size(payload));
 306 }
 307
 308 /**
 309  * genlmsg_new - Allocate a new generic netlink message
 310  * @payload: size of the message payload
 311  * @flags: the type of memory to allocate.
 312  */
 313 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
 314 {
 315         return nlmsg_new(genlmsg_total_size(payload), flags);
 316 }
 317
 318
 319 #endif  /* __NET_GENERIC_NETLINK_H */