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