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