1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided 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 AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY 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, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/types.h>
29#include <sys/ck.h>
30#include <sys/epoch.h>
31#include <sys/eventhandler.h>
32#include <sys/kernel.h>
33#include <sys/jail.h>
34#include <sys/lock.h>
35#include <sys/malloc.h>
36#include <sys/priv.h>
37#include <sys/socket.h>
38#include <sys/sx.h>
39
40#include <netlink/netlink.h>
41#include <netlink/netlink_ctl.h>
42#include <netlink/netlink_generic.h>
43#include <netlink/netlink_var.h>
44
45#define	DEBUG_MOD_NAME	nl_generic
46#define	DEBUG_MAX_LEVEL	LOG_DEBUG3
47#include <netlink/netlink_debug.h>
48_DECLARE_DEBUG(LOG_INFO);
49
50static int dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr,
51    const struct genl_family *gf, struct nl_writer *nw);
52
53/*
54 * Handler called by netlink subsystem when matching netlink message is received
55 */
56static int
57genl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt)
58{
59	struct nlpcb *nlp = npt->nlp;
60	struct genl_family *gf = NULL;
61	int error = 0;
62
63	int family_id = (int)hdr->nlmsg_type - GENL_MIN_ID;
64
65	if (__predict_false(family_id < 0 || (gf = genl_get_family(family_id)) == NULL)) {
66		NLP_LOG(LOG_DEBUG, nlp, "invalid message type: %d", hdr->nlmsg_type);
67		return (ENOTSUP);
68	}
69
70	if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) {
71		NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len);
72		return (EINVAL);
73	}
74
75	struct genlmsghdr *ghdr = (struct genlmsghdr *)(hdr + 1);
76
77	if (ghdr->cmd >= gf->family_cmd_size || gf->family_cmds[ghdr->cmd].cmd_cb == NULL) {
78		NLP_LOG(LOG_DEBUG, nlp, "family %s: invalid cmd %d",
79		    gf->family_name, ghdr->cmd);
80		return (ENOTSUP);
81	}
82
83	struct genl_cmd *cmd = &gf->family_cmds[ghdr->cmd];
84
85	if (cmd->cmd_priv != 0 && !nlp_has_priv(nlp, cmd->cmd_priv)) {
86		NLP_LOG(LOG_DEBUG, nlp, "family %s: cmd %d priv_check() failed",
87		    gf->family_name, ghdr->cmd);
88		return (EPERM);
89	}
90
91	NLP_LOG(LOG_DEBUG2, nlp, "received family %s cmd %s(%d) len %d",
92	    gf->family_name, cmd->cmd_name, ghdr->cmd, hdr->nlmsg_len);
93
94	error = cmd->cmd_cb(hdr, npt);
95
96	return (error);
97}
98
99static uint32_t
100get_cmd_flags(const struct genl_cmd *cmd)
101{
102	uint32_t flags = cmd->cmd_flags;
103	if (cmd->cmd_priv != 0)
104		flags |= GENL_ADMIN_PERM;
105	return (flags);
106}
107
108static int
109dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr,
110    const struct genl_family *gf, struct nl_writer *nw)
111{
112	if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr)))
113		goto enomem;
114
115	struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
116	ghdr_new->cmd = ghdr->cmd;
117	ghdr_new->version = gf->family_version;
118	ghdr_new->reserved = 0;
119
120        nlattr_add_string(nw, CTRL_ATTR_FAMILY_NAME, gf->family_name);
121        nlattr_add_u16(nw, CTRL_ATTR_FAMILY_ID, gf->family_id);
122        nlattr_add_u32(nw, CTRL_ATTR_VERSION, gf->family_version);
123        nlattr_add_u32(nw, CTRL_ATTR_HDRSIZE, gf->family_hdrsize);
124        nlattr_add_u32(nw, CTRL_ATTR_MAXATTR, gf->family_attr_max);
125
126	if (gf->family_cmd_size > 0) {
127		int off = nlattr_add_nested(nw, CTRL_ATTR_OPS);
128		if (off == 0)
129			goto enomem;
130		for (int i = 0, cnt=0; i < gf->family_cmd_size; i++) {
131			struct genl_cmd *cmd = &gf->family_cmds[i];
132			if (cmd->cmd_cb == NULL)
133				continue;
134			int cmd_off = nlattr_add_nested(nw, ++cnt);
135			if (cmd_off == 0)
136				goto enomem;
137
138			nlattr_add_u32(nw, CTRL_ATTR_OP_ID, cmd->cmd_num);
139			nlattr_add_u32(nw, CTRL_ATTR_OP_FLAGS, get_cmd_flags(cmd));
140			nlattr_set_len(nw, cmd_off);
141		}
142		nlattr_set_len(nw, off);
143	}
144	if (gf->family_num_groups > 0) {
145		int off = nlattr_add_nested(nw, CTRL_ATTR_MCAST_GROUPS);
146		if (off == 0)
147			goto enomem;
148		for (int i = 0, cnt = 0; i < MAX_GROUPS; i++) {
149			struct genl_group *gg = genl_get_group(i);
150			if (gg == NULL || gg->group_family != gf)
151				continue;
152
153			int cmd_off = nlattr_add_nested(nw, ++cnt);
154			if (cmd_off == 0)
155				goto enomem;
156			nlattr_add_u32(nw, CTRL_ATTR_MCAST_GRP_ID, i + MIN_GROUP_NUM);
157			nlattr_add_string(nw, CTRL_ATTR_MCAST_GRP_NAME, gg->group_name);
158			nlattr_set_len(nw, cmd_off);
159		}
160		nlattr_set_len(nw, off);
161	}
162	if (nlmsg_end(nw))
163		return (0);
164enomem:
165        NL_LOG(LOG_DEBUG, "unable to dump family %s state (ENOMEM)", gf->family_name);
166        nlmsg_abort(nw);
167	return (ENOMEM);
168}
169
170
171/* Declare ourself as a user */
172static void nlctrl_notify(void *arg, const struct genl_family *gf, int action);
173static eventhandler_tag family_event_tag;
174
175static uint32_t ctrl_family_id;
176static uint32_t ctrl_group_id;
177
178struct nl_parsed_family {
179	uint32_t	family_id;
180	char		*family_name;
181	uint8_t		version;
182};
183
184#define	_IN(_field)	offsetof(struct genlmsghdr, _field)
185#define	_OUT(_field)	offsetof(struct nl_parsed_family, _field)
186static const struct nlfield_parser nlf_p_generic[] = {
187	{ .off_in = _IN(version), .off_out = _OUT(version), .cb = nlf_get_u8 },
188};
189
190static struct nlattr_parser nla_p_generic[] = {
191	{ .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(family_id), .cb = nlattr_get_uint16 },
192	{ .type = CTRL_ATTR_FAMILY_NAME , .off = _OUT(family_name), .cb = nlattr_get_string },
193};
194#undef _IN
195#undef _OUT
196NL_DECLARE_PARSER(genl_parser, struct genlmsghdr, nlf_p_generic, nla_p_generic);
197
198static bool
199match_family(const struct genl_family *gf, const struct nl_parsed_family *attrs)
200{
201	if (gf->family_name == NULL)
202		return (false);
203	if (attrs->family_id != 0 && attrs->family_id != gf->family_id)
204		return (false);
205	if (attrs->family_name != NULL && strcmp(attrs->family_name, gf->family_name))
206		return (false);
207	return (true);
208}
209
210static int
211nlctrl_handle_getfamily(struct nlmsghdr *hdr, struct nl_pstate *npt)
212{
213	int error = 0;
214
215	struct nl_parsed_family attrs = {};
216	error = nl_parse_nlmsg(hdr, &genl_parser, npt, &attrs);
217	if (error != 0)
218		return (error);
219
220	struct genlmsghdr ghdr = {
221		.cmd = CTRL_CMD_NEWFAMILY,
222	};
223
224	if (attrs.family_id != 0 || attrs.family_name != NULL) {
225		/* Resolve request */
226		for (int i = 0; i < MAX_FAMILIES; i++) {
227			struct genl_family *gf = genl_get_family(i);
228			if (gf != NULL && match_family(gf, &attrs)) {
229				error = dump_family(hdr, &ghdr, gf, npt->nw);
230				return (error);
231			}
232		}
233		return (ENOENT);
234	}
235
236	hdr->nlmsg_flags = hdr->nlmsg_flags | NLM_F_MULTI;
237	for (int i = 0; i < MAX_FAMILIES; i++) {
238		struct genl_family *gf = genl_get_family(i);
239		if (gf != NULL && match_family(gf, &attrs)) {
240			error = dump_family(hdr, &ghdr, gf, npt->nw);
241			if (error != 0)
242				break;
243		}
244	}
245
246	if (!nlmsg_end_dump(npt->nw, error, hdr)) {
247                NL_LOG(LOG_DEBUG, "Unable to finalize the dump");
248                return (ENOMEM);
249        }
250
251	return (error);
252}
253
254static void
255nlctrl_notify(void *arg __unused, const struct genl_family *gf, int cmd)
256{
257	struct nlmsghdr hdr = {.nlmsg_type = NETLINK_GENERIC };
258	struct genlmsghdr ghdr = { .cmd = cmd };
259	struct nl_writer nw = {};
260
261	if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_GENERIC, ctrl_group_id)) {
262		dump_family(&hdr, &ghdr, gf, &nw);
263		nlmsg_flush(&nw);
264		return;
265	}
266	NL_LOG(LOG_DEBUG, "error allocating group writer");
267}
268
269static const struct genl_cmd nlctrl_cmds[] = {
270	{
271		.cmd_num = CTRL_CMD_GETFAMILY,
272		.cmd_name = "GETFAMILY",
273		.cmd_cb = nlctrl_handle_getfamily,
274		.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
275	},
276};
277
278static const struct nlhdr_parser *all_parsers[] = { &genl_parser };
279
280static void
281genl_load_all(void *u __unused)
282{
283	NL_VERIFY_PARSERS(all_parsers);
284	ctrl_family_id = genl_register_family(CTRL_FAMILY_NAME, 0, 2, CTRL_ATTR_MAX);
285	genl_register_cmds(CTRL_FAMILY_NAME, nlctrl_cmds, NL_ARRAY_LEN(nlctrl_cmds));
286	ctrl_group_id = genl_register_group(CTRL_FAMILY_NAME, "notify");
287	family_event_tag = EVENTHANDLER_REGISTER(genl_family_event, nlctrl_notify, NULL,
288	    EVENTHANDLER_PRI_ANY);
289	netlink_register_proto(NETLINK_GENERIC, "NETLINK_GENERIC", genl_handle_message);
290}
291SYSINIT(genl_load_all, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_load_all, NULL);
292
293static void
294genl_unload(void *u __unused)
295{
296	netlink_unregister_proto(NETLINK_GENERIC);
297	EVENTHANDLER_DEREGISTER(genl_family_event, family_event_tag);
298	genl_unregister_family(CTRL_FAMILY_NAME);
299	NET_EPOCH_WAIT();
300}
301SYSUNINIT(genl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_unload, NULL);
302