1 /*
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 2023 Baptiste Daroussin <bapt@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted providing that the following conditions~
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
23 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
24 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <sys/param.h>
29 #include <sys/module.h>
30 #include <sys/socket.h>
31
32 #include <stdint.h>
33 #include <stdlib.h>
34 #include <unistd.h>
35 #include <err.h>
36 #include <stdio.h>
37 #include <poll.h>
38
39 #include <netlink/netlink.h>
40 #include <netlink/netlink_generic.h>
41 #include <netlink/netlink_snl.h>
42 #include <netlink/netlink_snl_generic.h>
43
44 static int monitor_mcast(int argc, char **argv);
45 static int list_families(int argc, char **argv);
46 static void parser_nlctrl_notify(struct snl_state *ss, struct nlmsghdr *hdr);
47 static void parser_fallback(struct snl_state *ss, struct nlmsghdr *hdr);
48
49 static struct commands {
50 const char *name;
51 const char *usage;
52 int (*cmd)(int argc, char **argv);
53 } cmds[] = {
54 { "monitor", "monitor <family> <multicast group>", monitor_mcast },
55 { "list", "list", list_families },
56 };
57
58 static struct mcast_parsers {
59 const char *family;
60 void (*parser)(struct snl_state *ss, struct nlmsghdr *hdr);
61 } mcast_parsers [] = {
62 { "nlctrl", parser_nlctrl_notify },
63 };
64
65 struct genl_ctrl_op {
66 uint32_t id;
67 uint32_t flags;
68 };
69
70 struct genl_ctrl_ops {
71 uint32_t num_ops;
72 struct genl_ctrl_op **ops;
73 };
74
75 #define _OUT(_field) offsetof(struct genl_ctrl_op, _field)
76 static struct snl_attr_parser _nla_p_getops[] = {
77 { .type = CTRL_ATTR_OP_ID, .off = _OUT(id), .cb = snl_attr_get_uint32},
78 { .type = CTRL_ATTR_OP_FLAGS, .off = _OUT(flags), .cb = snl_attr_get_uint32 },
79 };
80 #undef _OUT
81 SNL_DECLARE_ATTR_PARSER_EXT(genl_ctrl_op_parser,
82 sizeof(struct genl_ctrl_op),
83 _nla_p_getops, NULL);
84
85 struct genl_family {
86 uint16_t id;
87 char *name;
88 uint32_t version;
89 uint32_t hdrsize;
90 uint32_t max_attr;
91 struct snl_genl_ctrl_mcast_groups mcast_groups;
92 struct genl_ctrl_ops ops;
93 };
94
95 #define _OUT(_field) offsetof(struct genl_family, _field)
96 static struct snl_attr_parser _nla_p_getfamily[] = {
97 { .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(id), .cb = snl_attr_get_uint16 },
98 { .type = CTRL_ATTR_FAMILY_NAME, .off = _OUT(name), .cb = snl_attr_get_string },
99 { .type = CTRL_ATTR_VERSION, .off = _OUT(version), .cb = snl_attr_get_uint32 },
100 { .type = CTRL_ATTR_VERSION, .off = _OUT(hdrsize), .cb = snl_attr_get_uint32 },
101 { .type = CTRL_ATTR_MAXATTR, .off = _OUT(max_attr), .cb = snl_attr_get_uint32 },
102 {
103 .type = CTRL_ATTR_OPS,
104 .off = _OUT(ops),
105 .cb = snl_attr_get_parray,
106 .arg = &genl_ctrl_op_parser,
107 },
108 {
109 .type = CTRL_ATTR_MCAST_GROUPS,
110 .off = _OUT(mcast_groups),
111 .cb = snl_attr_get_parray,
112 .arg = &_genl_ctrl_mc_parser,
113 },
114 };
115 #undef _OUT
116 SNL_DECLARE_GENL_PARSER(genl_family_parser, _nla_p_getfamily);
117
118 static struct op_capability {
119 uint32_t flag;
120 const char *str;
121 } op_caps[] = {
122 { GENL_ADMIN_PERM, "requires admin permission" },
123 { GENL_CMD_CAP_DO, "can modify" },
124 { GENL_CMD_CAP_DUMP, "can get/dump" },
125 { GENL_CMD_CAP_HASPOL, "has policy" },
126 };
127
128 static void
dump_operations(struct genl_ctrl_ops * ops)129 dump_operations(struct genl_ctrl_ops *ops)
130 {
131 if (ops->num_ops == 0)
132 return;
133 printf("\tsupported operations: \n");
134 for (uint32_t i = 0; i < ops->num_ops; i++) {
135 printf("\t - ID: %#02x, Capabilities: %#02x (",
136 ops->ops[i]->id,
137 ops->ops[i]->flags);
138 for (size_t j = 0; j < nitems(op_caps); j++)
139 if ((ops->ops[i]->flags & op_caps[j].flag) == op_caps[j].flag)
140 printf("%s; ", op_caps[j].str);
141 printf("\b\b)\n");
142 }
143 }
144
145 static void
dump_mcast_groups(struct snl_genl_ctrl_mcast_groups * mcast_groups)146 dump_mcast_groups( struct snl_genl_ctrl_mcast_groups *mcast_groups)
147 {
148 if (mcast_groups->num_groups == 0)
149 return;
150 printf("\tmulticast groups: \n");
151 for (uint32_t i = 0; i < mcast_groups->num_groups; i++)
152 printf("\t - ID: %#02x, Name: %s\n",
153 mcast_groups->groups[i]->mcast_grp_id,
154 mcast_groups->groups[i]->mcast_grp_name);
155 }
156
157 static void
usage(void)158 usage(void)
159 {
160 fprintf(stderr, "Usage: %s\n", getprogname());
161 for (size_t i = 0; i < nitems(cmds); i++)
162 fprintf(stderr, " %s %s\n", getprogname(), cmds[i].usage);
163 }
164
165 static void
dump_family(struct genl_family * family)166 dump_family(struct genl_family *family)
167 {
168 printf("Name: %s\n\tID: %#02hx, Version: %#02x, "
169 "header size: %d, max attributes: %d\n",
170 family->name, family->id, family->version,
171 family->hdrsize, family->max_attr);
172 dump_operations(&family->ops);
173 dump_mcast_groups(&family->mcast_groups);
174 }
175
176 void
parser_nlctrl_notify(struct snl_state * ss,struct nlmsghdr * hdr)177 parser_nlctrl_notify(struct snl_state *ss, struct nlmsghdr *hdr)
178 {
179 struct genl_family family = {};
180
181 if (snl_parse_nlmsg(ss, hdr, &genl_family_parser,
182 &family))
183 dump_family(&family);
184 }
185
186 void
parser_fallback(struct snl_state * ss __unused,struct nlmsghdr * hdr __unused)187 parser_fallback(struct snl_state *ss __unused, struct nlmsghdr *hdr __unused)
188 {
189 printf("New unknown message\n");
190 }
191
192 int
monitor_mcast(int argc __unused,char ** argv)193 monitor_mcast(int argc __unused, char **argv)
194 {
195 struct snl_state ss;
196 struct nlmsghdr *hdr;
197 struct _getfamily_attrs attrs;
198 struct pollfd pfd;
199 bool found = false;
200 void (*parser)(struct snl_state *ss, struct nlmsghdr *hdr);
201
202 parser = parser_fallback;
203
204 if (!snl_init(&ss, NETLINK_GENERIC))
205 err(EXIT_FAILURE, "snl_init()");
206
207 if (argc != 2) {
208 usage();
209 return (EXIT_FAILURE);
210 }
211 if (!snl_get_genl_family_info(&ss, argv[0], &attrs))
212 errx(EXIT_FAILURE, "Unknown family '%s'", argv[0]);
213 for (uint32_t i = 0; i < attrs.mcast_groups.num_groups; i++) {
214 if (strcmp(attrs.mcast_groups.groups[i]->mcast_grp_name,
215 argv[1]) == 0) {
216 found = true;
217 if (setsockopt(ss.fd, SOL_NETLINK,
218 NETLINK_ADD_MEMBERSHIP,
219 (void *)&attrs.mcast_groups.groups[i]->mcast_grp_id,
220 sizeof(attrs.mcast_groups.groups[i]->mcast_grp_id))
221 == -1)
222 err(EXIT_FAILURE, "Cannot subscribe to command "
223 "notify");
224 break;
225 }
226 }
227 if (!found)
228 errx(EXIT_FAILURE, "No such multicat group '%s'"
229 " in family '%s'", argv[1], argv[0]);
230 for (size_t i= 0; i < nitems(mcast_parsers); i++) {
231 if (strcmp(mcast_parsers[i].family, argv[0]) == 0) {
232 parser = mcast_parsers[i].parser;
233 break;
234 }
235 }
236 memset(&pfd, 0, sizeof(pfd));
237 pfd.fd = ss.fd;
238 pfd.events = POLLIN | POLLERR;
239 while (true) {
240 pfd.revents = 0;
241 if (poll(&pfd, 1, -1) == -1) {
242 if (errno == EINTR)
243 continue;
244 err(EXIT_FAILURE, "poll()");
245 }
246 hdr = snl_read_message(&ss);
247 if (hdr != NULL && hdr->nlmsg_type != NLMSG_ERROR)
248 parser(&ss, hdr);
249
250 }
251
252 return (EXIT_SUCCESS);
253 }
254
255 int
list_families(int argc,char ** argv __unused)256 list_families(int argc, char **argv __unused)
257 {
258 struct snl_state ss;
259 struct snl_writer nw;
260 struct nlmsghdr *hdr;
261 struct snl_errmsg_data e = {};
262 uint32_t seq_id;
263
264 if (argc != 0) {
265 usage();
266 return (EXIT_FAILURE);
267 }
268 if (!snl_init(&ss, NETLINK_GENERIC))
269 err(EXIT_FAILURE, "snl_init()");
270
271 snl_init_writer(&ss, &nw);
272 hdr = snl_create_genl_msg_request(&nw, GENL_ID_CTRL,
273 CTRL_CMD_GETFAMILY);
274 if ((hdr = snl_finalize_msg(&nw)) == NULL)
275 err(EXIT_FAILURE, "snl_finalize_msg");
276 seq_id = hdr->nlmsg_seq;
277 if (!snl_send_message(&ss, hdr))
278 err(EXIT_FAILURE, "snl_send_message");
279
280 while ((hdr = snl_read_reply_multi(&ss, seq_id, &e)) != NULL) {
281 if (e.error != 0) {
282 err(EXIT_FAILURE, "Error reading generic netlink");
283 }
284 struct genl_family family = {};
285 if (snl_parse_nlmsg(&ss, hdr, &genl_family_parser, &family))
286 dump_family(&family);
287 }
288
289 return (EXIT_SUCCESS);
290 }
291
292 int
main(int argc,char ** argv)293 main(int argc, char **argv)
294 {
295 if (modfind("netlink") == -1)
296 err(EXIT_FAILURE, "require netlink module to be loaded");
297
298 if (argc == 1)
299 return (list_families(0, NULL));
300
301 for (size_t i = 0; i < nitems(cmds); i++) {
302 if (strcmp(argv[1], cmds[i].name) == 0)
303 return (cmds[i].cmd(argc - 2, argv + 2));
304 }
305 usage();
306
307 return (EXIT_FAILURE);
308 }
309