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a3c4b484 JP |
1 | /* |
2 | * mnlg.c Generic Netlink helpers for libmnl | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | * | |
9 | * Authors: Jiri Pirko <jiri@mellanox.com> | |
10 | */ | |
11 | ||
12 | #include <stdlib.h> | |
13 | #include <stdbool.h> | |
14 | #include <string.h> | |
15 | #include <errno.h> | |
16 | #include <unistd.h> | |
17 | #include <time.h> | |
18 | #include <libmnl/libmnl.h> | |
19 | #include <linux/genetlink.h> | |
20 | ||
049c5853 AS |
21 | #include "libnetlink.h" |
22 | #include "utils.h" | |
a3c4b484 JP |
23 | #include "mnlg.h" |
24 | ||
25 | struct mnlg_socket { | |
26 | struct mnl_socket *nl; | |
27 | char *buf; | |
28 | uint32_t id; | |
29 | uint8_t version; | |
30 | unsigned int seq; | |
31 | unsigned int portid; | |
32 | }; | |
33 | ||
34 | static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd, | |
35 | uint16_t flags, uint32_t id, | |
36 | uint8_t version) | |
37 | { | |
38 | struct nlmsghdr *nlh; | |
39 | struct genlmsghdr *genl; | |
40 | ||
41 | nlh = mnl_nlmsg_put_header(nlg->buf); | |
42 | nlh->nlmsg_type = id; | |
43 | nlh->nlmsg_flags = flags; | |
44 | nlg->seq = time(NULL); | |
45 | nlh->nlmsg_seq = nlg->seq; | |
46 | ||
47 | genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr)); | |
48 | genl->cmd = cmd; | |
49 | genl->version = version; | |
50 | ||
51 | return nlh; | |
52 | } | |
53 | ||
54 | struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd, | |
55 | uint16_t flags) | |
56 | { | |
57 | return __mnlg_msg_prepare(nlg, cmd, flags, nlg->id, nlg->version); | |
58 | } | |
59 | ||
60 | int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh) | |
61 | { | |
62 | return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len); | |
63 | } | |
64 | ||
049c5853 AS |
65 | static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data) |
66 | { | |
67 | return MNL_CB_OK; | |
68 | } | |
69 | ||
70 | static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data) | |
71 | { | |
72 | const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh); | |
73 | ||
049c5853 AS |
74 | /* Netlink subsystems returns the errno value with different signess */ |
75 | if (err->error < 0) | |
76 | errno = -err->error; | |
77 | else | |
78 | errno = err->error; | |
79 | ||
f85adc61 AS |
80 | if (nl_dump_ext_ack(nlh, NULL)) |
81 | return MNL_CB_ERROR; | |
82 | ||
049c5853 AS |
83 | return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR; |
84 | } | |
85 | ||
86 | static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data) | |
87 | { | |
c934da8a MS |
88 | int len = *(int *)NLMSG_DATA(nlh); |
89 | ||
90 | if (len < 0) { | |
91 | errno = -len; | |
92 | nl_dump_ext_ack_done(nlh, len); | |
93 | return MNL_CB_ERROR; | |
94 | } | |
049c5853 AS |
95 | return MNL_CB_STOP; |
96 | } | |
97 | ||
98 | static mnl_cb_t mnlg_cb_array[NLMSG_MIN_TYPE] = { | |
99 | [NLMSG_NOOP] = mnlg_cb_noop, | |
100 | [NLMSG_ERROR] = mnlg_cb_error, | |
101 | [NLMSG_DONE] = mnlg_cb_stop, | |
102 | [NLMSG_OVERRUN] = mnlg_cb_noop, | |
103 | }; | |
104 | ||
a3c4b484 JP |
105 | int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data) |
106 | { | |
107 | int err; | |
108 | ||
109 | do { | |
110 | err = mnl_socket_recvfrom(nlg->nl, nlg->buf, | |
111 | MNL_SOCKET_BUFFER_SIZE); | |
112 | if (err <= 0) | |
113 | break; | |
049c5853 AS |
114 | err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid, |
115 | data_cb, data, mnlg_cb_array, | |
116 | ARRAY_SIZE(mnlg_cb_array)); | |
a3c4b484 JP |
117 | } while (err > 0); |
118 | ||
119 | return err; | |
120 | } | |
121 | ||
122 | struct group_info { | |
123 | bool found; | |
124 | uint32_t id; | |
125 | const char *name; | |
126 | }; | |
127 | ||
128 | static int parse_mc_grps_cb(const struct nlattr *attr, void *data) | |
129 | { | |
130 | const struct nlattr **tb = data; | |
131 | int type = mnl_attr_get_type(attr); | |
132 | ||
133 | if (mnl_attr_type_valid(attr, CTRL_ATTR_MCAST_GRP_MAX) < 0) | |
134 | return MNL_CB_OK; | |
135 | ||
136 | switch (type) { | |
137 | case CTRL_ATTR_MCAST_GRP_ID: | |
138 | if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) | |
139 | return MNL_CB_ERROR; | |
140 | break; | |
141 | case CTRL_ATTR_MCAST_GRP_NAME: | |
142 | if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) | |
143 | return MNL_CB_ERROR; | |
144 | break; | |
145 | } | |
146 | tb[type] = attr; | |
147 | return MNL_CB_OK; | |
148 | } | |
149 | ||
150 | static void parse_genl_mc_grps(struct nlattr *nested, | |
151 | struct group_info *group_info) | |
152 | { | |
153 | struct nlattr *pos; | |
154 | const char *name; | |
155 | ||
156 | mnl_attr_for_each_nested(pos, nested) { | |
157 | struct nlattr *tb[CTRL_ATTR_MCAST_GRP_MAX + 1] = {}; | |
158 | ||
159 | mnl_attr_parse_nested(pos, parse_mc_grps_cb, tb); | |
160 | if (!tb[CTRL_ATTR_MCAST_GRP_NAME] || | |
161 | !tb[CTRL_ATTR_MCAST_GRP_ID]) | |
162 | continue; | |
163 | ||
164 | name = mnl_attr_get_str(tb[CTRL_ATTR_MCAST_GRP_NAME]); | |
165 | if (strcmp(name, group_info->name) != 0) | |
166 | continue; | |
167 | ||
168 | group_info->id = mnl_attr_get_u32(tb[CTRL_ATTR_MCAST_GRP_ID]); | |
169 | group_info->found = true; | |
170 | } | |
171 | } | |
172 | ||
173 | static int get_group_id_attr_cb(const struct nlattr *attr, void *data) | |
174 | { | |
175 | const struct nlattr **tb = data; | |
176 | int type = mnl_attr_get_type(attr); | |
177 | ||
178 | if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0) | |
179 | return MNL_CB_ERROR; | |
180 | ||
181 | if (type == CTRL_ATTR_MCAST_GROUPS && | |
182 | mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) | |
183 | return MNL_CB_ERROR; | |
184 | tb[type] = attr; | |
185 | return MNL_CB_OK; | |
186 | } | |
187 | ||
188 | static int get_group_id_cb(const struct nlmsghdr *nlh, void *data) | |
189 | { | |
190 | struct group_info *group_info = data; | |
191 | struct nlattr *tb[CTRL_ATTR_MAX + 1] = {}; | |
192 | struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh); | |
193 | ||
194 | mnl_attr_parse(nlh, sizeof(*genl), get_group_id_attr_cb, tb); | |
195 | if (!tb[CTRL_ATTR_MCAST_GROUPS]) | |
196 | return MNL_CB_ERROR; | |
197 | parse_genl_mc_grps(tb[CTRL_ATTR_MCAST_GROUPS], group_info); | |
198 | return MNL_CB_OK; | |
199 | } | |
200 | ||
201 | int mnlg_socket_group_add(struct mnlg_socket *nlg, const char *group_name) | |
202 | { | |
203 | struct nlmsghdr *nlh; | |
204 | struct group_info group_info; | |
205 | int err; | |
206 | ||
207 | nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY, | |
208 | NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1); | |
7f57c8b7 | 209 | mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, nlg->id); |
a3c4b484 JP |
210 | |
211 | err = mnlg_socket_send(nlg, nlh); | |
212 | if (err < 0) | |
213 | return err; | |
214 | ||
215 | group_info.found = false; | |
216 | group_info.name = group_name; | |
217 | err = mnlg_socket_recv_run(nlg, get_group_id_cb, &group_info); | |
218 | if (err < 0) | |
219 | return err; | |
220 | ||
221 | if (!group_info.found) { | |
222 | errno = ENOENT; | |
223 | return -1; | |
224 | } | |
225 | ||
226 | err = mnl_socket_setsockopt(nlg->nl, NETLINK_ADD_MEMBERSHIP, | |
227 | &group_info.id, sizeof(group_info.id)); | |
228 | if (err < 0) | |
229 | return err; | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | static int get_family_id_attr_cb(const struct nlattr *attr, void *data) | |
235 | { | |
236 | const struct nlattr **tb = data; | |
237 | int type = mnl_attr_get_type(attr); | |
238 | ||
239 | if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0) | |
240 | return MNL_CB_ERROR; | |
241 | ||
242 | if (type == CTRL_ATTR_FAMILY_ID && | |
243 | mnl_attr_validate(attr, MNL_TYPE_U16) < 0) | |
244 | return MNL_CB_ERROR; | |
245 | tb[type] = attr; | |
246 | return MNL_CB_OK; | |
247 | } | |
248 | ||
249 | static int get_family_id_cb(const struct nlmsghdr *nlh, void *data) | |
250 | { | |
251 | uint32_t *p_id = data; | |
252 | struct nlattr *tb[CTRL_ATTR_MAX + 1] = {}; | |
253 | struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh); | |
254 | ||
255 | mnl_attr_parse(nlh, sizeof(*genl), get_family_id_attr_cb, tb); | |
256 | if (!tb[CTRL_ATTR_FAMILY_ID]) | |
257 | return MNL_CB_ERROR; | |
258 | *p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]); | |
259 | return MNL_CB_OK; | |
260 | } | |
261 | ||
262 | struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version) | |
263 | { | |
264 | struct mnlg_socket *nlg; | |
265 | struct nlmsghdr *nlh; | |
049c5853 | 266 | int one = 1; |
a3c4b484 JP |
267 | int err; |
268 | ||
269 | nlg = malloc(sizeof(*nlg)); | |
270 | if (!nlg) | |
271 | return NULL; | |
272 | ||
273 | nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE); | |
274 | if (!nlg->buf) | |
275 | goto err_buf_alloc; | |
276 | ||
277 | nlg->nl = mnl_socket_open(NETLINK_GENERIC); | |
278 | if (!nlg->nl) | |
279 | goto err_mnl_socket_open; | |
280 | ||
9e4a92e5 IV |
281 | /* Older kernels may no support capped/extended ACK reporting */ |
282 | mnl_socket_setsockopt(nlg->nl, NETLINK_CAP_ACK, &one, sizeof(one)); | |
283 | mnl_socket_setsockopt(nlg->nl, NETLINK_EXT_ACK, &one, sizeof(one)); | |
049c5853 | 284 | |
a3c4b484 JP |
285 | err = mnl_socket_bind(nlg->nl, 0, MNL_SOCKET_AUTOPID); |
286 | if (err < 0) | |
287 | goto err_mnl_socket_bind; | |
288 | ||
289 | nlg->portid = mnl_socket_get_portid(nlg->nl); | |
290 | ||
291 | nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY, | |
292 | NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1); | |
293 | mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name); | |
294 | ||
295 | err = mnlg_socket_send(nlg, nlh); | |
296 | if (err < 0) | |
297 | goto err_mnlg_socket_send; | |
298 | ||
299 | err = mnlg_socket_recv_run(nlg, get_family_id_cb, &nlg->id); | |
300 | if (err < 0) | |
301 | goto err_mnlg_socket_recv_run; | |
302 | ||
303 | nlg->version = version; | |
304 | return nlg; | |
305 | ||
306 | err_mnlg_socket_recv_run: | |
307 | err_mnlg_socket_send: | |
308 | err_mnl_socket_bind: | |
309 | mnl_socket_close(nlg->nl); | |
310 | err_mnl_socket_open: | |
311 | free(nlg->buf); | |
312 | err_buf_alloc: | |
313 | free(nlg); | |
314 | return NULL; | |
315 | } | |
316 | ||
317 | void mnlg_socket_close(struct mnlg_socket *nlg) | |
318 | { | |
319 | mnl_socket_close(nlg->nl); | |
320 | free(nlg->buf); | |
321 | free(nlg); | |
322 | } |