xref: /freebsd/sys/netlink/netlink_glue.c (revision 9f44a47fd07924afc035991af15d84e6585dea4f)
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 "opt_netlink.h"
29 
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/malloc.h>
33 #include <sys/lock.h>
34 #include <sys/rmlock.h>
35 #include <sys/domain.h>
36 #include <sys/mbuf.h>
37 #include <sys/protosw.h>
38 #include <sys/proc.h>
39 #include <sys/ck.h>
40 #include <sys/socket.h>
41 #include <sys/socketvar.h>
42 #include <sys/sysent.h>
43 #include <sys/syslog.h>
44 #include <sys/priv.h> /* priv_check */
45 
46 #include <net/route.h>
47 #include <net/route/route_ctl.h>
48 
49 #include <netlink/netlink.h>
50 #include <netlink/netlink_ctl.h>
51 #include <netlink/netlink_var.h>
52 #include <netlink/route/route_var.h>
53 
54 /* Standard bits: built-in the kernel */
55 SYSCTL_NODE(_net, OID_AUTO, netlink, CTLFLAG_RD, 0, "");
56 SYSCTL_NODE(_net_netlink, OID_AUTO, debug, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
57 
58 MALLOC_DEFINE(M_NETLINK, "netlink", "Memory used for netlink packets");
59 
60 /* Netlink-related callbacks needed to glue rtsock, netlink and linuxolator */
61 static void
62 ignore_route_event(uint32_t fibnum, const struct rib_cmd_info *rc)
63 {
64 }
65 
66 static void
67 ignore_ifmsg_event(struct ifnet *ifp, int if_flags_mask)
68 {
69 }
70 
71 static struct rtbridge ignore_cb = {
72 	.route_f = ignore_route_event,
73 	.ifmsg_f = ignore_ifmsg_event,
74 };
75 
76 void *linux_netlink_p = NULL; /* Callback pointer for Linux translator functions */
77 struct rtbridge *rtsock_callback_p = &ignore_cb;
78 struct rtbridge *netlink_callback_p = &ignore_cb;
79 
80 
81 /*
82  * nlp accessors.
83  * TODO: move to a separate file once the number grows.
84  */
85 bool
86 nlp_has_priv(struct nlpcb *nlp, int priv)
87 {
88 	return (priv_check_cred(nlp->nl_cred, priv) == 0);
89 }
90 
91 struct ucred *
92 nlp_get_cred(struct nlpcb *nlp)
93 {
94 	return (nlp->nl_cred);
95 }
96 
97 uint32_t
98 nlp_get_pid(const struct nlpcb *nlp)
99 {
100 	return (nlp->nl_process_id);
101 }
102 
103 bool
104 nlp_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 
112 static bool
113 get_stub_writer(struct nl_writer *nw)
114 {
115 	bzero(nw, sizeof(*nw));
116 	nw->writer_type = NS_WRITER_TYPE_STUB;
117 	nw->enomem = true;
118 
119 	return (false);
120 }
121 
122 static bool
123 nlmsg_get_unicast_writer_stub(struct nl_writer *nw, int size, struct nlpcb *nlp)
124 {
125 	return (get_stub_writer(nw));
126 }
127 
128 static bool
129 nlmsg_get_group_writer_stub(struct nl_writer *nw, int size, int protocol, int group_id)
130 {
131 	return (get_stub_writer(nw));
132 }
133 
134 static bool
135 nlmsg_get_chain_writer_stub(struct nl_writer *nw, int size, struct mbuf **pm)
136 {
137 	return (get_stub_writer(nw));
138 }
139 
140 static bool
141 nlmsg_flush_stub(struct nl_writer *nw __unused)
142 {
143 	return (false);
144 }
145 
146 static void
147 nlmsg_ignore_limit_stub(struct nl_writer *nw __unused)
148 {
149 }
150 
151 static bool
152 nlmsg_refill_buffer_stub(struct nl_writer *nw __unused, int required_len __unused)
153 {
154 	return (false);
155 }
156 
157 static bool
158 nlmsg_add_stub(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
159     uint16_t flags, uint32_t len)
160 {
161 	return (false);
162 }
163 
164 static bool
165 nlmsg_end_stub(struct nl_writer *nw __unused)
166 {
167 	return (false);
168 }
169 
170 static void
171 nlmsg_abort_stub(struct nl_writer *nw __unused)
172 {
173 }
174 
175 static bool
176 nlmsg_end_dump_stub(struct nl_writer *nw, int error, struct nlmsghdr *hdr)
177 {
178 	return (false);
179 }
180 
181 static int
182 nl_modify_ifp_generic_stub(struct ifnet *ifp __unused,
183     struct nl_parsed_link *lattrs __unused, const struct nlattr_bmask *bm __unused,
184     struct nl_pstate *npt __unused)
185 {
186 	return (ENOTSUP);
187 }
188 
189 static void
190 nl_store_ifp_cookie_stub(struct nl_pstate *npt __unused, struct ifnet *ifp __unused)
191 {
192 }
193 
194 static struct nlpcb *
195 nl_get_thread_nlp_stub(struct thread *td __unused)
196 {
197 	return (NULL);
198 }
199 
200 const static struct nl_function_wrapper nl_stub = {
201 	.nlmsg_add = nlmsg_add_stub,
202 	.nlmsg_refill_buffer = nlmsg_refill_buffer_stub,
203 	.nlmsg_flush = nlmsg_flush_stub,
204 	.nlmsg_end = nlmsg_end_stub,
205 	.nlmsg_abort = nlmsg_abort_stub,
206 	.nlmsg_ignore_limit = nlmsg_ignore_limit_stub,
207 	.nlmsg_get_unicast_writer = nlmsg_get_unicast_writer_stub,
208 	.nlmsg_get_group_writer = nlmsg_get_group_writer_stub,
209 	.nlmsg_get_chain_writer = nlmsg_get_chain_writer_stub,
210 	.nlmsg_end_dump = nlmsg_end_dump_stub,
211 	.nl_modify_ifp_generic = nl_modify_ifp_generic_stub,
212 	.nl_store_ifp_cookie = nl_store_ifp_cookie_stub,
213 	.nl_get_thread_nlp = nl_get_thread_nlp_stub,
214 };
215 
216 /*
217  * If the kernel is compiled with netlink as a module,
218  *  provide a way to introduce non-stub functioms
219  */
220 static const struct nl_function_wrapper *_nl = &nl_stub;
221 
222 void
223 nl_set_functions(const struct nl_function_wrapper *nl)
224 {
225 	_nl = (nl != NULL) ? nl : &nl_stub;
226 }
227 
228 /* Function wrappers */
229 bool
230 nlmsg_get_unicast_writer(struct nl_writer *nw, int size, struct nlpcb *nlp)
231 {
232 	return (_nl->nlmsg_get_unicast_writer(nw, size, nlp));
233 }
234 
235 bool
236 nlmsg_get_group_writer(struct nl_writer *nw, int size, int protocol, int group_id)
237 {
238 	return (_nl->nlmsg_get_group_writer(nw, size, protocol, group_id));
239 }
240 
241 bool
242 nlmsg_get_chain_writer(struct nl_writer *nw, int size, struct mbuf **pm)
243 {
244 	return (_nl->nlmsg_get_chain_writer(nw, size, pm));
245 }
246 
247 bool
248 nlmsg_flush(struct nl_writer *nw)
249 {
250 	return (_nl->nlmsg_flush(nw));
251 }
252 
253 void nlmsg_ignore_limit(struct nl_writer *nw)
254 {
255 	_nl->nlmsg_ignore_limit(nw);
256 }
257 
258 bool
259 nlmsg_refill_buffer(struct nl_writer *nw, int required_len)
260 {
261 	return (_nl->nlmsg_refill_buffer(nw, required_len));
262 }
263 
264 bool
265 nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
266     uint16_t flags, uint32_t len)
267 {
268 	return (_nl->nlmsg_add(nw, portid, seq, type, flags, len));
269 }
270 
271 bool
272 nlmsg_end(struct nl_writer *nw)
273 {
274 	return (_nl->nlmsg_end(nw));
275 }
276 
277 void
278 nlmsg_abort(struct nl_writer *nw)
279 {
280 	_nl->nlmsg_abort(nw);
281 }
282 
283 bool
284 nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr)
285 {
286 	return (_nl->nlmsg_end_dump(nw, error, hdr));
287 }
288 
289 int
290 nl_modify_ifp_generic(struct ifnet *ifp, struct nl_parsed_link *lattrs,
291     const struct nlattr_bmask *bm , struct nl_pstate *npt)
292 {
293 	return (_nl->nl_modify_ifp_generic(ifp, lattrs, bm, npt));
294 }
295 
296 void
297 nl_store_ifp_cookie(struct nl_pstate *npt, struct ifnet *ifp)
298 {
299 	return (_nl->nl_store_ifp_cookie(npt, ifp));
300 }
301 
302 struct nlpcb *
303 nl_get_thread_nlp(struct thread *td)
304 {
305 	return (_nl->nl_get_thread_nlp(td));
306 }
307 
308 #endif /* !NETLINK */
309 
310