1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2023 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/param.h>
29#include <sys/kernel.h>
30#include <sys/malloc.h>
31#include <sys/lock.h>
32#include <sys/rmlock.h>
33#include <sys/domain.h>
34#include <sys/mbuf.h>
35#include <sys/protosw.h>
36#include <sys/proc.h>
37#include <sys/ck.h>
38#include <sys/socket.h>
39#include <sys/socketvar.h>
40#include <sys/sysent.h>
41#include <sys/syslog.h>
42#include <sys/priv.h> /* priv_check */
43
44#include <net/route.h>
45#include <net/route/route_ctl.h>
46
47#include <netlink/netlink.h>
48#include <netlink/netlink_ctl.h>
49#include <netlink/netlink_var.h>
50#include <netlink/route/route_var.h>
51
52/* Standard bits: built-in the kernel */
53SYSCTL_NODE(_net, OID_AUTO, netlink, CTLFLAG_RD, 0,
54    "RFC3549 Netlink network state socket family");
55SYSCTL_NODE(_net_netlink, OID_AUTO, debug, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
56    "Netlink per-subsystem debug levels");
57
58MALLOC_DEFINE(M_NETLINK, "netlink", "Memory used for netlink packets");
59
60/* Netlink-related callbacks needed to glue rtsock, netlink and linuxolator */
61static void
62ignore_route_event(uint32_t fibnum, const struct rib_cmd_info *rc)
63{
64}
65
66static void
67ignore_ifmsg_event(struct ifnet *ifp, int if_flags_mask)
68{
69}
70
71static struct rtbridge ignore_cb = {
72	.route_f = ignore_route_event,
73	.ifmsg_f = ignore_ifmsg_event,
74};
75
76void *linux_netlink_p = NULL; /* Callback pointer for Linux translator functions */
77struct rtbridge *rtsock_callback_p = &ignore_cb;
78struct rtbridge *netlink_callback_p = &ignore_cb;
79
80
81/*
82 * nlp accessors.
83 * TODO: move to a separate file once the number grows.
84 */
85bool
86nlp_has_priv(struct nlpcb *nlp, int priv)
87{
88	return (priv_check_cred(nlp->nl_cred, priv) == 0);
89}
90
91struct ucred *
92nlp_get_cred(struct nlpcb *nlp)
93{
94	return (nlp->nl_cred);
95}
96
97uint32_t
98nlp_get_pid(const struct nlpcb *nlp)
99{
100	return (nlp->nl_process_id);
101}
102
103bool
104nlp_unconstrained_vnet(const struct nlpcb *nlp)
105{
106	return (nlp->nl_unconstrained_vnet);
107}
108
109#ifndef NETLINK
110/* Stub implementations for the loadable functions */
111
112static bool
113get_stub_writer(struct nl_writer *nw)
114{
115	bzero(nw, sizeof(*nw));
116	nw->enomem = true;
117
118	return (false);
119}
120
121static bool
122nlmsg_get_unicast_writer_stub(struct nl_writer *nw, int size, struct nlpcb *nlp)
123{
124	return (get_stub_writer(nw));
125}
126
127static bool
128nlmsg_get_group_writer_stub(struct nl_writer *nw, int size, int protocol, int group_id)
129{
130	return (get_stub_writer(nw));
131}
132
133static bool
134nlmsg_get_chain_writer_stub(struct nl_writer *nw, int size, struct mbuf **pm)
135{
136	return (get_stub_writer(nw));
137}
138
139static bool
140nlmsg_flush_stub(struct nl_writer *nw __unused)
141{
142	return (false);
143}
144
145static void
146nlmsg_ignore_limit_stub(struct nl_writer *nw __unused)
147{
148}
149
150static bool
151nlmsg_refill_buffer_stub(struct nl_writer *nw __unused, int required_len __unused)
152{
153	return (false);
154}
155
156static bool
157nlmsg_add_stub(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
158    uint16_t flags, uint32_t len)
159{
160	return (false);
161}
162
163static bool
164nlmsg_end_stub(struct nl_writer *nw __unused)
165{
166	return (false);
167}
168
169static void
170nlmsg_abort_stub(struct nl_writer *nw __unused)
171{
172}
173
174static bool
175nlmsg_end_dump_stub(struct nl_writer *nw, int error, struct nlmsghdr *hdr)
176{
177	return (false);
178}
179
180static int
181nl_modify_ifp_generic_stub(struct ifnet *ifp __unused,
182    struct nl_parsed_link *lattrs __unused, const struct nlattr_bmask *bm __unused,
183    struct nl_pstate *npt __unused)
184{
185	return (ENOTSUP);
186}
187
188static void
189nl_store_ifp_cookie_stub(struct nl_pstate *npt __unused, struct ifnet *ifp __unused)
190{
191}
192
193static struct nlpcb *
194nl_get_thread_nlp_stub(struct thread *td __unused)
195{
196	return (NULL);
197}
198
199const static struct nl_function_wrapper nl_stub = {
200	.nlmsg_add = nlmsg_add_stub,
201	.nlmsg_refill_buffer = nlmsg_refill_buffer_stub,
202	.nlmsg_flush = nlmsg_flush_stub,
203	.nlmsg_end = nlmsg_end_stub,
204	.nlmsg_abort = nlmsg_abort_stub,
205	.nlmsg_ignore_limit = nlmsg_ignore_limit_stub,
206	.nlmsg_get_unicast_writer = nlmsg_get_unicast_writer_stub,
207	.nlmsg_get_group_writer = nlmsg_get_group_writer_stub,
208	.nlmsg_get_chain_writer = nlmsg_get_chain_writer_stub,
209	.nlmsg_end_dump = nlmsg_end_dump_stub,
210	.nl_modify_ifp_generic = nl_modify_ifp_generic_stub,
211	.nl_store_ifp_cookie = nl_store_ifp_cookie_stub,
212	.nl_get_thread_nlp = nl_get_thread_nlp_stub,
213};
214
215/*
216 * If the kernel is compiled with netlink as a module,
217 *  provide a way to introduce non-stub functioms
218 */
219static const struct nl_function_wrapper *_nl = &nl_stub;
220
221void
222nl_set_functions(const struct nl_function_wrapper *nl)
223{
224	_nl = (nl != NULL) ? nl : &nl_stub;
225}
226
227/* Function wrappers */
228bool
229nlmsg_get_unicast_writer(struct nl_writer *nw, int size, struct nlpcb *nlp)
230{
231	return (_nl->nlmsg_get_unicast_writer(nw, size, nlp));
232}
233
234bool
235nlmsg_get_group_writer(struct nl_writer *nw, int size, int protocol, int group_id)
236{
237	return (_nl->nlmsg_get_group_writer(nw, size, protocol, group_id));
238}
239
240bool
241nlmsg_get_chain_writer(struct nl_writer *nw, int size, struct mbuf **pm)
242{
243	return (_nl->nlmsg_get_chain_writer(nw, size, pm));
244}
245
246bool
247nlmsg_flush(struct nl_writer *nw)
248{
249	return (_nl->nlmsg_flush(nw));
250}
251
252void nlmsg_ignore_limit(struct nl_writer *nw)
253{
254	_nl->nlmsg_ignore_limit(nw);
255}
256
257bool
258nlmsg_refill_buffer(struct nl_writer *nw, int required_len)
259{
260	return (_nl->nlmsg_refill_buffer(nw, required_len));
261}
262
263bool
264nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
265    uint16_t flags, uint32_t len)
266{
267	return (_nl->nlmsg_add(nw, portid, seq, type, flags, len));
268}
269
270bool
271nlmsg_end(struct nl_writer *nw)
272{
273	return (_nl->nlmsg_end(nw));
274}
275
276void
277nlmsg_abort(struct nl_writer *nw)
278{
279	_nl->nlmsg_abort(nw);
280}
281
282bool
283nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr)
284{
285	return (_nl->nlmsg_end_dump(nw, error, hdr));
286}
287
288int
289nl_modify_ifp_generic(struct ifnet *ifp, struct nl_parsed_link *lattrs,
290    const struct nlattr_bmask *bm , struct nl_pstate *npt)
291{
292	return (_nl->nl_modify_ifp_generic(ifp, lattrs, bm, npt));
293}
294
295void
296nl_store_ifp_cookie(struct nl_pstate *npt, struct ifnet *ifp)
297{
298	return (_nl->nl_store_ifp_cookie(npt, ifp));
299}
300
301struct nlpcb *
302nl_get_thread_nlp(struct thread *td)
303{
304	return (_nl->nl_get_thread_nlp(td));
305}
306
307#endif /* !NETLINK */
308
309