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_put_reply - Add generic netlink header to a reply message
 164  * @skb: socket buffer holding the message
 165  * @info: receiver info
 166  * @family: generic netlink family
 167  * @flags: netlink message flags
 168  * @cmd: generic netlink command
 169  *
 170  * Returns pointer to user specific header
 171  */
 172 static inline void *genlmsg_put_reply(struct sk_buff *skb,
 173                                       struct genl_info *info,
 174                                       struct genl_family *family,
 175                                       int flags, u8 cmd)
 176 {
 177         return genlmsg_put(skb, info->snd_pid, info->snd_seq, family,
 178                            flags, cmd);
 179 }
 180
 181 /**
 182  * genlmsg_end - Finalize a generic netlink message
 183  * @skb: socket buffer the message is stored in
 184  * @hdr: user specific header
 185  */
 186 static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
 187 {
 188         return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 189 }
 190
 191 /**
 192  * genlmsg_cancel - Cancel construction of a generic netlink message
 193  * @skb: socket buffer the message is stored in
 194  * @hdr: generic netlink message header
 195  */
 196 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 197 {
 198         if (hdr)
 199                 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 200 }
 201
 202 /**
 203  * genlmsg_multicast_netns - multicast a netlink message to a specific netns
 204  * @net: the net namespace
 205  * @skb: netlink message as socket buffer
 206  * @pid: own netlink pid to avoid sending to yourself
 207  * @group: multicast group id
 208  * @flags: allocation flags
 209  */
 210 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
 211                                           u32 pid, unsigned int group, gfp_t flags)
 212 {
 213         return nlmsg_multicast(net->genl_sock, skb, pid, group, flags);
 214 }
 215
 216 /**
 217  * genlmsg_multicast - multicast a netlink message to the default netns
 218  * @skb: netlink message as socket buffer
 219  * @pid: own netlink pid to avoid sending to yourself
 220  * @group: multicast group id
 221  * @flags: allocation flags
 222  */
 223 static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid,
 224                                     unsigned int group, gfp_t flags)
 225 {
 226         return genlmsg_multicast_netns(&init_net, skb, pid, group, flags);
 227 }
 228
 229 /**
 230  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
 231  * @skb: netlink message as socket buffer
 232  * @pid: own netlink pid to avoid sending to yourself
 233  * @group: multicast group id
 234  * @flags: allocation flags
 235  *
 236  * This function must hold the RTNL or rcu_read_lock().
 237  */
 238 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid,
 239                             unsigned int group, gfp_t flags);
 240
 241 /**
 242  * genlmsg_unicast - unicast a netlink message
 243  * @skb: netlink message as socket buffer
 244  * @pid: netlink pid of the destination socket
 245  */
 246 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid)
 247 {
 248         return nlmsg_unicast(net->genl_sock, skb, pid);
 249 }
 250
 251 /**
 252  * genlmsg_reply - reply to a request
 253  * @skb: netlink message to be sent back
 254  * @info: receiver information
 255  */
 256 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
 257 {
 258         return genlmsg_unicast(genl_info_net(info), skb, info->snd_pid);
 259 }
 260
 261 /**
 262  * gennlmsg_data - head of message payload
 263  * @gnlh: genetlink messsage header
 264  */
 265 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
 266 {
 267         return ((unsigned char *) gnlh + GENL_HDRLEN);
 268 }
 269
 270 /**
 271  * genlmsg_len - length of message payload
 272  * @gnlh: genetlink message header
 273  */
 274 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
 275 {
 276         struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
 277                                                         NLMSG_HDRLEN);
 278         return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
 279 }
 280
 281 /**
 282  * genlmsg_msg_size - length of genetlink message not including padding
 283  * @payload: length of message payload
 284  */
 285 static inline int genlmsg_msg_size(int payload)
 286 {
 287         return GENL_HDRLEN + payload;
 288 }
 289
 290 /**
 291  * genlmsg_total_size - length of genetlink message including padding
 292  * @payload: length of message payload
 293  */
 294 static inline int genlmsg_total_size(int payload)
 295 {
 296         return NLMSG_ALIGN(genlmsg_msg_size(payload));
 297 }
 298
 299 /**
 300  * genlmsg_new - Allocate a new generic netlink message
 301  * @payload: size of the message payload
 302  * @flags: the type of memory to allocate.
 303  */
 304 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
 305 {
 306         return nlmsg_new(genlmsg_total_size(payload), flags);
 307 }
 308
 309
 310 #endif  /* __NET_GENERIC_NETLINK_H */