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 {
  18         struct genl_family      *family;        /* private */
  19         struct list_head        list;           /* private */
  20         char                    name[GENL_NAMSIZ];
  21         u32                     id;
  22 };
  23
  24 /**
  25  * struct genl_family - generic netlink family
  26  * @id: protocol family idenfitier
  27  * @hdrsize: length of user specific header in bytes
  28  * @name: name of family
  29  * @version: protocol version
  30  * @maxattr: maximum number of attributes supported
  31  * @netnsok: set to true if the family can handle network
  32  *      namespaces and should be presented in all of them
  33  * @attrbuf: buffer to store parsed attributes
  34  * @ops_list: list of all assigned operations
  35  * @family_list: family list
  36  * @mcast_groups: multicast groups list
  37  */
  38 struct genl_family
  39 {
  40         unsigned int            id;
  41         unsigned int            hdrsize;
  42         char                    name[GENL_NAMSIZ];
  43         unsigned int            version;
  44         unsigned int            maxattr;
  45         bool                    netnsok;
  46         struct nlattr **        attrbuf;        /* private */
  47         struct list_head        ops_list;       /* private */
  48         struct list_head        family_list;    /* private */
  49         struct list_head        mcast_groups;   /* private */
  50 };
  51
  52 /**
  53  * struct genl_info - receiving information
  54  * @snd_seq: sending sequence number
  55  * @snd_pid: netlink pid of sender
  56  * @nlhdr: netlink message header
  57  * @genlhdr: generic netlink message header
  58  * @userhdr: user specific header
  59  * @attrs: netlink attributes
  60  */
  61 struct genl_info
  62 {
  63         u32                     snd_seq;
  64         u32                     snd_pid;
  65         struct nlmsghdr *       nlhdr;
  66         struct genlmsghdr *     genlhdr;
  67         void *                  userhdr;
  68         struct nlattr **        attrs;
  69 #ifdef CONFIG_NET_NS
  70         struct net *            _net;
  71 #endif
  72 };
  73
  74 #ifdef CONFIG_NET_NS
  75 static inline struct net *genl_info_net(struct genl_info *info)
  76 {
  77         return info->_net;
  78 }
  79
  80 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  81 {
  82         info->_net = net;
  83 }
  84 #else
  85 static inline struct net *genl_info_net(struct genl_info *info)
  86 {
  87         return &init_net;
  88 }
  89
  90 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  91 {
  92 }
  93 #endif
  94
  95 /**
  96  * struct genl_ops - generic netlink operations
  97  * @cmd: command identifier
  98  * @flags: flags
  99  * @policy: attribute validation policy
 100  * @doit: standard command callback
 101  * @dumpit: callback for dumpers
 102  * @done: completion callback for dumps
 103  * @ops_list: operations list
 104  */
 105 struct genl_ops
 106 {
 107         u8                      cmd;
 108         unsigned int            flags;
 109         const struct nla_policy *policy;
 110         int                    (*doit)(struct sk_buff *skb,
 111                                        struct genl_info *info);
 112         int                    (*dumpit)(struct sk_buff *skb,
 113                                          struct netlink_callback *cb);
 114         int                    (*done)(struct netlink_callback *cb);
 115         struct list_head        ops_list;
 116 };
 117
 118 extern int genl_register_family(struct genl_family *family);
 119 extern int genl_register_family_with_ops(struct genl_family *family,
 120         struct genl_ops *ops, size_t n_ops);
 121 extern int genl_unregister_family(struct genl_family *family);
 122 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
 123 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
 124 extern int genl_register_mc_group(struct genl_family *family,
 125                                   struct genl_multicast_group *grp);
 126 extern void genl_unregister_mc_group(struct genl_family *family,
 127                                      struct genl_multicast_group *grp);
 128
 129 /**
 130  * genlmsg_put - Add generic netlink header to netlink message
 131  * @skb: socket buffer holding the message
 132  * @pid: netlink pid the message is addressed to
 133  * @seq: sequence number (usually the one of the sender)
 134  * @family: generic netlink family
 135  * @flags netlink message flags
 136  * @cmd: generic netlink command
 137  *
 138  * Returns pointer to user specific header
 139  */
 140 static inline void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 141                                 struct genl_family *family, int flags, u8 cmd)
 142 {
 143         struct nlmsghdr *nlh;
 144         struct genlmsghdr *hdr;
 145
 146         nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
 147                         family->hdrsize, flags);
 148         if (nlh == NULL)
 149                 return NULL;
 150
 151         hdr = nlmsg_data(nlh);
 152         hdr->cmd = cmd;
 153         hdr->version = family->version;
 154         hdr->reserved = 0;
 155
 156         return (char *) hdr + GENL_HDRLEN;
 157 }
 158
 159 /**
 160  * genlmsg_put_reply - Add generic netlink header to a reply message
 161  * @skb: socket buffer holding the message
 162  * @info: receiver info
 163  * @family: generic netlink family
 164  * @flags: netlink message flags
 165  * @cmd: generic netlink command
 166  *
 167  * Returns pointer to user specific header
 168  */
 169 static inline void *genlmsg_put_reply(struct sk_buff *skb,
 170                                       struct genl_info *info,
 171                                       struct genl_family *family,
 172                                       int flags, u8 cmd)
 173 {
 174         return genlmsg_put(skb, info->snd_pid, info->snd_seq, family,
 175                            flags, cmd);
 176 }
 177
 178 /**
 179  * genlmsg_end - Finalize a generic netlink message
 180  * @skb: socket buffer the message is stored in
 181  * @hdr: user specific header
 182  */
 183 static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
 184 {
 185         return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 186 }
 187
 188 /**
 189  * genlmsg_cancel - Cancel construction of a generic netlink message
 190  * @skb: socket buffer the message is stored in
 191  * @hdr: generic netlink message header
 192  */
 193 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 194 {
 195         nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 196 }
 197
 198 /**
 199  * genlmsg_multicast_netns - multicast a netlink message to a specific netns
 200  * @net: the net namespace
 201  * @skb: netlink message as socket buffer
 202  * @pid: own netlink pid to avoid sending to yourself
 203  * @group: multicast group id
 204  * @flags: allocation flags
 205  */
 206 static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
 207                                           u32 pid, unsigned int group, gfp_t flags)
 208 {
 209         return nlmsg_multicast(net->genl_sock, skb, pid, group, flags);
 210 }
 211
 212 /**
 213  * genlmsg_multicast - multicast a netlink message to the default netns
 214  * @skb: netlink message as socket buffer
 215  * @pid: own netlink pid to avoid sending to yourself
 216  * @group: multicast group id
 217  * @flags: allocation flags
 218  */
 219 static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid,
 220                                     unsigned int group, gfp_t flags)
 221 {
 222         return genlmsg_multicast_netns(&init_net, skb, pid, group, flags);
 223 }
 224
 225 /**
 226  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
 227  * @skb: netlink message as socket buffer
 228  * @pid: own netlink pid to avoid sending to yourself
 229  * @group: multicast group id
 230  * @flags: allocation flags
 231  *
 232  * This function must hold the RTNL or rcu_read_lock().
 233  */
 234 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid,
 235                             unsigned int group, gfp_t flags);
 236
 237 /**
 238  * genlmsg_unicast - unicast a netlink message
 239  * @skb: netlink message as socket buffer
 240  * @pid: netlink pid of the destination socket
 241  */
 242 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid)
 243 {
 244         return nlmsg_unicast(net->genl_sock, skb, pid);
 245 }
 246
 247 /**
 248  * genlmsg_reply - reply to a request
 249  * @skb: netlink message to be sent back
 250  * @info: receiver information
 251  */
 252 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
 253 {
 254         return genlmsg_unicast(genl_info_net(info), skb, info->snd_pid);
 255 }
 256
 257 /**
 258  * gennlmsg_data - head of message payload
 259  * @gnlh: genetlink messsage header
 260  */
 261 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
 262 {
 263         return ((unsigned char *) gnlh + GENL_HDRLEN);
 264 }
 265
 266 /**
 267  * genlmsg_len - length of message payload
 268  * @gnlh: genetlink message header
 269  */
 270 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
 271 {
 272         struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
 273                                                         NLMSG_HDRLEN);
 274         return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
 275 }
 276
 277 /**
 278  * genlmsg_msg_size - length of genetlink message not including padding
 279  * @payload: length of message payload
 280  */
 281 static inline int genlmsg_msg_size(int payload)
 282 {
 283         return GENL_HDRLEN + payload;
 284 }
 285
 286 /**
 287  * genlmsg_total_size - length of genetlink message including padding
 288  * @payload: length of message payload
 289  */
 290 static inline int genlmsg_total_size(int payload)
 291 {
 292         return NLMSG_ALIGN(genlmsg_msg_size(payload));
 293 }
 294
 295 /**
 296  * genlmsg_new - Allocate a new generic netlink message
 297  * @payload: size of the message payload
 298  * @flags: the type of memory to allocate.
 299  */
 300 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
 301 {
 302         return nlmsg_new(genlmsg_total_size(payload), flags);
 303 }
 304
 305
 306 #endif  /* __NET_GENERIC_NETLINK_H */