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authorThomas Graf <tgraf@suug.ch>2005-11-09 20:25:56 -0500
committerThomas Graf <tgr@axs.localdomain>2005-11-09 20:26:41 -0500
commit482a8524f85a7d8c40c6fb5d072e85bc2fef327f (patch)
treecbd4225da63a687dd70441d41aad35ff5c171f48 /include
parent9ac4a16983ea4edf719c390a1a234d956947688d (diff)
[NETLINK]: Generic netlink family
The generic netlink family builds on top of netlink and provides simplifies access for the less demanding netlink users. It solves the problem of protocol numbers running out by introducing a so called controller taking care of id management and name resolving. Generic netlink modules register themself after filling out their id card (struct genl_family), after successful registration the modules are able to register callbacks to command numbers by filling out a struct genl_ops and calling genl_register_op(). The registered callbacks are invoked with attributes parsed making life of simple modules a lot easier. Although generic netlink modules can request static identifiers, it is recommended to use GENL_ID_GENERATE and to let the controller assign a unique identifier to the module. Userspace applications will then ask the controller and lookup the idenfier by the module name. Due to the current multicast implementation of netlink, the number of generic netlink modules is restricted to 1024 to avoid wasting memory for the per socket multiacst subscription bitmask. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/genetlink.h51
-rw-r--r--include/net/genetlink.h154
2 files changed, 205 insertions, 0 deletions
diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
new file mode 100644
index 000000000000..84f12a41dc01
--- /dev/null
+++ b/include/linux/genetlink.h
@@ -0,0 +1,51 @@
1#ifndef __LINUX_GENERIC_NETLINK_H
2#define __LINUX_GENERIC_NETLINK_H
3
4#include <linux/netlink.h>
5
6#define GENL_NAMSIZ 16 /* length of family name */
7
8#define GENL_MIN_ID NLMSG_MIN_TYPE
9#define GENL_MAX_ID 1023
10
11struct genlmsghdr {
12 __u8 cmd;
13 __u8 version;
14 __u16 reserved;
15};
16
17#define GENL_HDRLEN NLMSG_ALIGN(sizeof(struct genlmsghdr))
18
19/*
20 * List of reserved static generic netlink identifiers:
21 */
22#define GENL_ID_GENERATE 0
23#define GENL_ID_CTRL NLMSG_MIN_TYPE
24
25/**************************************************************************
26 * Controller
27 **************************************************************************/
28
29enum {
30 CTRL_CMD_UNSPEC,
31 CTRL_CMD_NEWFAMILY,
32 CTRL_CMD_DELFAMILY,
33 CTRL_CMD_GETFAMILY,
34 CTRL_CMD_NEWOPS,
35 CTRL_CMD_DELOPS,
36 CTRL_CMD_GETOPS,
37 __CTRL_CMD_MAX,
38};
39
40#define CTRL_CMD_MAX (__CTRL_CMD_MAX - 1)
41
42enum {
43 CTRL_ATTR_UNSPEC,
44 CTRL_ATTR_FAMILY_ID,
45 CTRL_ATTR_FAMILY_NAME,
46 __CTRL_ATTR_MAX,
47};
48
49#define CTRL_ATTR_MAX (__CTRL_ATTR_MAX - 1)
50
51#endif /* __LINUX_GENERIC_NETLINK_H */
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
new file mode 100644
index 000000000000..52d8b1a73d52
--- /dev/null
+++ b/include/net/genetlink.h
@@ -0,0 +1,154 @@
1#ifndef __NET_GENERIC_NETLINK_H
2#define __NET_GENERIC_NETLINK_H
3
4#include <linux/genetlink.h>
5#include <net/netlink.h>
6
7/**
8 * struct genl_family - generic netlink family
9 * @id: protocol family idenfitier
10 * @hdrsize: length of user specific header in bytes
11 * @name: name of family
12 * @version: protocol version
13 * @maxattr: maximum number of attributes supported
14 * @attrbuf: buffer to store parsed attributes
15 * @ops_list: list of all assigned operations
16 * @family_list: family list
17 */
18struct genl_family
19{
20 unsigned int id;
21 unsigned int hdrsize;
22 char name[GENL_NAMSIZ];
23 unsigned int version;
24 unsigned int maxattr;
25 struct module * owner;
26 struct nlattr ** attrbuf; /* private */
27 struct list_head ops_list; /* private */
28 struct list_head family_list; /* private */
29};
30
31#define GENL_ADMIN_PERM 0x01
32
33/**
34 * struct genl_info - receiving information
35 * @snd_seq: sending sequence number
36 * @snd_pid: netlink pid of sender
37 * @nlhdr: netlink message header
38 * @genlhdr: generic netlink message header
39 * @userhdr: user specific header
40 * @attrs: netlink attributes
41 */
42struct genl_info
43{
44 u32 snd_seq;
45 u32 snd_pid;
46 struct nlmsghdr * nlhdr;
47 struct genlmsghdr * genlhdr;
48 void * userhdr;
49 struct nlattr ** attrs;
50};
51
52/**
53 * struct genl_ops - generic netlink operations
54 * @cmd: command identifier
55 * @flags: flags
56 * @policy: attribute validation policy
57 * @doit: standard command callback
58 * @dumpit: callback for dumpers
59 * @ops_list: operations list
60 */
61struct genl_ops
62{
63 unsigned int cmd;
64 unsigned int flags;
65 struct nla_policy *policy;
66 int (*doit)(struct sk_buff *skb,
67 struct genl_info *info);
68 int (*dumpit)(struct sk_buff *skb,
69 struct netlink_callback *cb);
70 struct list_head ops_list;
71};
72
73extern int genl_register_family(struct genl_family *family);
74extern int genl_unregister_family(struct genl_family *family);
75extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
76extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
77
78extern struct sock *genl_sock;
79
80/**
81 * genlmsg_put - Add generic netlink header to netlink message
82 * @skb: socket buffer holding the message
83 * @pid: netlink pid the message is addressed to
84 * @seq: sequence number (usually the one of the sender)
85 * @type: netlink message type
86 * @hdrlen: length of the user specific header
87 * @flags netlink message flags
88 * @cmd: generic netlink command
89 * @version: version
90 *
91 * Returns pointer to user specific header
92 */
93static inline void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
94 int type, int hdrlen, int flags,
95 u8 cmd, u8 version)
96{
97 struct nlmsghdr *nlh;
98 struct genlmsghdr *hdr;
99
100 nlh = nlmsg_put(skb, pid, seq, type, GENL_HDRLEN + hdrlen, flags);
101 if (nlh == NULL)
102 return NULL;
103
104 hdr = nlmsg_data(nlh);
105 hdr->cmd = cmd;
106 hdr->version = version;
107 hdr->reserved = 0;
108
109 return (char *) hdr + GENL_HDRLEN;
110}
111
112/**
113 * genlmsg_end - Finalize a generic netlink message
114 * @skb: socket buffer the message is stored in
115 * @hdr: user specific header
116 */
117static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
118{
119 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
120}
121
122/**
123 * genlmsg_cancel - Cancel construction of a generic netlink message
124 * @skb: socket buffer the message is stored in
125 * @hdr: generic netlink message header
126 */
127static inline int genlmsg_cancel(struct sk_buff *skb, void *hdr)
128{
129 return nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
130}
131
132/**
133 * genlmsg_multicast - multicast a netlink message
134 * @skb: netlink message as socket buffer
135 * @pid: own netlink pid to avoid sending to yourself
136 * @group: multicast group id
137 */
138static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid,
139 unsigned int group)
140{
141 return nlmsg_multicast(genl_sock, skb, pid, group);
142}
143
144/**
145 * genlmsg_unicast - unicast a netlink message
146 * @skb: netlink message as socket buffer
147 * @pid: netlink pid of the destination socket
148 */
149static inline int genlmsg_unicast(struct sk_buff *skb, u32 pid)
150{
151 return nlmsg_unicast(genl_sock, skb, pid);
152}
153
154#endif /* __NET_GENERIC_NETLINK_H */