add libnl-tiny as a small replacement for libnl with only genl support included
[openwrt/svn-archive/archive.git] / package / libnl-tiny / src / genl_mngt.c
1 /*
2 * lib/genl/mngt.c Generic Netlink Management
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation version 2.1
7 * of the License.
8 *
9 * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
10 */
11
12 /**
13 * @ingroup genl
14 * @defgroup genl_mngt Management
15 *
16 * @par 1) Registering a generic netlink module
17 * @code
18 * #include <netlink/genl/mngt.h>
19 *
20 * // First step is to define all the commands being used in
21 * // particular generic netlink family. The ID and name are
22 * // mandatory to be filled out. A callback function and
23 * // most the attribute policy that comes with it must be
24 * // defined for commands expected to be issued towards
25 * // userspace.
26 * static struct genl_cmd foo_cmds[] = {
27 * {
28 * .c_id = FOO_CMD_NEW,
29 * .c_name = "NEWFOO" ,
30 * .c_maxattr = FOO_ATTR_MAX,
31 * .c_attr_policy = foo_policy,
32 * .c_msg_parser = foo_msg_parser,
33 * },
34 * {
35 * .c_id = FOO_CMD_DEL,
36 * .c_name = "DELFOO" ,
37 * },
38 * };
39 *
40 * // The list of commands must then be integrated into a
41 * // struct genl_ops serving as handle for this particular
42 * // family.
43 * static struct genl_ops my_genl_ops = {
44 * .o_cmds = foo_cmds,
45 * .o_ncmds = ARRAY_SIZE(foo_cmds),
46 * };
47 *
48 * // Using the above struct genl_ops an arbitary number of
49 * // cache handles can be associated to it.
50 * //
51 * // The macro GENL_HDRSIZE() must be used to specify the
52 * // length of the header to automatically take headers on
53 * // generic layers into account.
54 * //
55 * // The macro GENL_FAMILY() is used to represent the generic
56 * // netlink family id.
57 * static struct nl_cache_ops genl_foo_ops = {
58 * .co_name = "genl/foo",
59 * .co_hdrsize = GENL_HDRSIZE(sizeof(struct my_hdr)),
60 * .co_msgtypes = GENL_FAMILY(GENL_ID_GENERATE, "foo"),
61 * .co_genl = &my_genl_ops,
62 * .co_protocol = NETLINK_GENERIC,
63 * .co_request_update = foo_request_update,
64 * .co_obj_ops = &genl_foo_ops,
65 * };
66 *
67 * // Finally each cache handle for a generic netlink family
68 * // must be registered using genl_register().
69 * static void __init foo_init(void)
70 * {
71 * genl_register(&genl_foo_ops);
72 * }
73 *
74 * // ... respectively unregsted again.
75 * static void __exit foo_exit(void)
76 * {
77 * genl_unregister(&genl_foo_ops);
78 * }
79 * @endcode
80 * @{
81 */
82
83 #include <netlink-generic.h>
84 #include <netlink/netlink.h>
85 #include <netlink/genl/genl.h>
86 #include <netlink/genl/mngt.h>
87 #include <netlink/genl/family.h>
88 #include <netlink/genl/ctrl.h>
89 #include <netlink/utils.h>
90
91 static NL_LIST_HEAD(genl_ops_list);
92
93 static int genl_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
94 struct nlmsghdr *nlh, struct nl_parser_param *pp)
95 {
96 int i, err;
97 struct genlmsghdr *ghdr;
98 struct genl_cmd *cmd;
99
100 ghdr = nlmsg_data(nlh);
101
102 if (ops->co_genl == NULL)
103 BUG();
104
105 for (i = 0; i < ops->co_genl->o_ncmds; i++) {
106 cmd = &ops->co_genl->o_cmds[i];
107 if (cmd->c_id == ghdr->cmd)
108 goto found;
109 }
110
111 err = -NLE_MSGTYPE_NOSUPPORT;
112 goto errout;
113
114 found:
115 if (cmd->c_msg_parser == NULL)
116 err = -NLE_OPNOTSUPP;
117 else {
118 struct nlattr *tb[cmd->c_maxattr + 1];
119 struct genl_info info = {
120 .who = who,
121 .nlh = nlh,
122 .genlhdr = ghdr,
123 .userhdr = genlmsg_data(ghdr),
124 .attrs = tb,
125 };
126
127 err = nlmsg_parse(nlh, ops->co_hdrsize, tb, cmd->c_maxattr,
128 cmd->c_attr_policy);
129 if (err < 0)
130 goto errout;
131
132 err = cmd->c_msg_parser(ops, cmd, &info, pp);
133 }
134 errout:
135 return err;
136
137 }
138
139 char *genl_op2name(int family, int op, char *buf, size_t len)
140 {
141 struct genl_ops *ops;
142 int i;
143
144 nl_list_for_each_entry(ops, &genl_ops_list, o_list) {
145 if (ops->o_family == family) {
146 for (i = 0; i < ops->o_ncmds; i++) {
147 struct genl_cmd *cmd;
148 cmd = &ops->o_cmds[i];
149
150 if (cmd->c_id == op) {
151 strncpy(buf, cmd->c_name, len - 1);
152 return buf;
153 }
154 }
155 }
156 }
157
158 strncpy(buf, "unknown", len - 1);
159 return NULL;
160 }
161
162
163 /**
164 * @name Register/Unregister
165 * @{
166 */
167
168 /**
169 * Register generic netlink operations
170 * @arg ops cache operations
171 */
172 int genl_register(struct nl_cache_ops *ops)
173 {
174 int err;
175
176 if (ops->co_protocol != NETLINK_GENERIC) {
177 err = -NLE_PROTO_MISMATCH;
178 goto errout;
179 }
180
181 if (ops->co_hdrsize < GENL_HDRSIZE(0)) {
182 err = -NLE_INVAL;
183 goto errout;
184 }
185
186 if (ops->co_genl == NULL) {
187 err = -NLE_INVAL;
188 goto errout;
189 }
190
191 ops->co_genl->o_cache_ops = ops;
192 ops->co_genl->o_name = ops->co_msgtypes[0].mt_name;
193 ops->co_genl->o_family = ops->co_msgtypes[0].mt_id;
194 ops->co_msg_parser = genl_msg_parser;
195
196 /* FIXME: check for dup */
197
198 nl_list_add_tail(&ops->co_genl->o_list, &genl_ops_list);
199
200 err = nl_cache_mngt_register(ops);
201 errout:
202 return err;
203 }
204
205 /**
206 * Unregister generic netlink operations
207 * @arg ops cache operations
208 */
209 void genl_unregister(struct nl_cache_ops *ops)
210 {
211 nl_cache_mngt_unregister(ops);
212 nl_list_del(&ops->co_genl->o_list);
213 }
214
215 /** @} */
216
217 /**
218 * @name Resolving ID/Name
219 * @{
220 */
221 #ifdef disabled
222 static int __genl_ops_resolve(struct nl_cache *ctrl, struct genl_ops *ops)
223 {
224 struct genl_family *family;
225
226 family = genl_ctrl_search_by_name(ctrl, ops->o_name);
227 if (family != NULL) {
228 ops->o_id = genl_family_get_id(family);
229 genl_family_put(family);
230
231 return 0;
232 }
233
234 return -NLE_OBJ_NOTFOUND;
235 }
236
237 int genl_ops_resolve(struct nl_sock *sk, struct genl_ops *ops)
238 {
239 struct nl_cache *ctrl;
240 int err;
241
242 if ((err = genl_ctrl_alloc_cache(sk, &ctrl)) < 0)
243 goto errout;
244
245 err = __genl_ops_resolve(ctrl, ops);
246
247 nl_cache_free(ctrl);
248 errout:
249 return err;
250 }
251
252 int genl_mngt_resolve(struct nl_sock *sk)
253 {
254 struct nl_cache *ctrl;
255 struct genl_ops *ops;
256 int err = 0;
257
258 if ((err = genl_ctrl_alloc_cache(sk, &ctrl)) < 0)
259 goto errout;
260
261 nl_list_for_each_entry(ops, &genl_ops_list, o_list) {
262 err = __genl_ops_resolve(ctrl, ops);
263 }
264
265 nl_cache_free(ctrl);
266 errout:
267 return err;
268 }
269 #endif
270 /** @} */
271
272
273 /** @} */