1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2021 Ng Peng Nam Sean
5 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef _NETLINK_NETLINK_MESSAGE_WRITER_H_
30#define _NETLINK_NETLINK_MESSAGE_WRITER_H_
31
32#ifdef _KERNEL
33
34#include <netinet/in.h>
35
36/*
37 * It is not meant to be included directly
38 */
39
40struct nl_buf;
41struct nl_writer;
42typedef bool nl_writer_cb(struct nl_writer *nw);
43
44struct nl_writer {
45 struct nl_buf *buf; /* Underlying storage pointer */
46 struct nlmsghdr *hdr; /* Pointer to the currently-filled msg */
47 nl_writer_cb *cb; /* Callback to flush data */
48 union {
49 struct nlpcb *nlp;
50 struct {
51 uint16_t proto;
52 uint16_t id;
53 int priv;
54 } group;
55 };
56 u_int num_messages; /* Number of messages in the buffer */
57 int malloc_flag; /* M_WAITOK or M_NOWAIT */
58 bool ignore_limit; /* If true, ignores RCVBUF limit */
59 bool enomem; /* True if ENOMEM occured */
60 bool suppress_ack; /* If true, don't send NLMSG_ERR */
61};
62
63#define NLMSG_SMALL 128
64#define NLMSG_LARGE 2048
65
66/* Message and attribute writing */
67#if defined(NETLINK) || defined(NETLINK_MODULE)
68/* Provide optimized calls to the functions inside the same linking unit */
69
70bool _nl_writer_unicast(struct nl_writer *, size_t, struct nlpcb *nlp, bool);
71bool _nl_writer_group(struct nl_writer *, size_t, uint16_t, uint16_t, int,
72 bool);
73bool _nlmsg_flush(struct nl_writer *nw);
74void _nlmsg_ignore_limit(struct nl_writer *nw);
75
76bool _nlmsg_refill_buffer(struct nl_writer *nw, size_t required_len);
77bool _nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq,
78 uint16_t type, uint16_t flags, uint32_t len);
79bool _nlmsg_end(struct nl_writer *nw);
80void _nlmsg_abort(struct nl_writer *nw);
81
82bool _nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
83
84
85static inline bool
86nl_writer_unicast(struct nl_writer *nw, size_t size, struct nlpcb *nlp,
87 bool waitok)
88{
89 return (_nl_writer_unicast(nw, size, nlp, waitok));
90}
91
92static inline bool
93nl_writer_group(struct nl_writer *nw, size_t size, uint16_t proto,
94 uint16_t group_id, int priv, bool waitok)
95{
96 return (_nl_writer_group(nw, size, proto, group_id, priv, waitok));
97}
98
99static inline bool
100nlmsg_flush(struct nl_writer *nw)
101{
102 return (_nlmsg_flush(nw));
103}
104
105static inline void
106nlmsg_ignore_limit(struct nl_writer *nw)
107{
108 _nlmsg_ignore_limit(nw);
109}
110
111static inline bool
112nlmsg_refill_buffer(struct nl_writer *nw, size_t required_size)
113{
114 return (_nlmsg_refill_buffer(nw, required_size));
115}
116
117static inline bool
118nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
119 uint16_t flags, uint32_t len)
120{
121 return (_nlmsg_add(nw, portid, seq, type, flags, len));
122}
123
124static inline bool
125nlmsg_end(struct nl_writer *nw)
126{
127 return (_nlmsg_end(nw));
128}
129
130static inline void
131nlmsg_abort(struct nl_writer *nw)
132{
133 return (_nlmsg_abort(nw));
134}
135
136static inline bool
137nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr)
138{
139 return (_nlmsg_end_dump(nw, error, hdr));
140}
141
142#else
143/* Provide access to the functions via netlink_glue.c */
144
145bool nl_writer_unicast(struct nl_writer *, size_t, struct nlpcb *, bool waitok);
146bool nl_writer_group(struct nl_writer *, size_t, uint16_t, uint16_t, int,
147 bool waitok);
148bool nlmsg_flush(struct nl_writer *nw);
149void nlmsg_ignore_limit(struct nl_writer *nw);
150
151bool nlmsg_refill_buffer(struct nl_writer *nw, size_t required_size);
152bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq,
153 uint16_t type, uint16_t flags, uint32_t len);
154bool nlmsg_end(struct nl_writer *nw);
155void nlmsg_abort(struct nl_writer *nw);
156
157bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
158
159#endif /* defined(NETLINK) || defined(NETLINK_MODULE) */
160
161static inline bool
162nlmsg_reply(struct nl_writer *nw, const struct nlmsghdr *hdr, int payload_len)
163{
164 return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type,
165 hdr->nlmsg_flags, payload_len));
166}
167
168/*
169 * KPI similar to mtodo():
170 * current (uncompleted) header is guaranteed to be contiguous,
171 * but can be reallocated, thus pointers may need to be readjusted.
172 */
173u_int nlattr_save_offset(const struct nl_writer *nw);
174
175static inline void *
176_nlattr_restore_offset(const struct nl_writer *nw, int off)
177{
178 return ((void *)((char *)nw->hdr + off));
179}
180#define nlattr_restore_offset(_ns, _off, _t) ((_t *)_nlattr_restore_offset(_ns, _off))
181
182static inline void
183nlattr_set_len(const struct nl_writer *nw, int off)
184{
185 struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr);
186 nla->nla_len = nlattr_save_offset(nw) - off;
187}
188
189void *nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz);
190#define nlmsg_reserve_object(_ns, _t) ((_t *)nlmsg_reserve_data_raw(_ns, sizeof(_t)))
191#define nlmsg_reserve_data(_ns, _sz, _t) ((_t *)nlmsg_reserve_data_raw(_ns, _sz))
192
193static inline int
194nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type)
195{
196 int off = nlattr_save_offset(nw);
197 struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr);
198 if (__predict_false(nla == NULL))
199 return (0);
200 nla->nla_type = nla_type;
201 return (off);
202}
203
204static inline void *
205_nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz)
206{
207 sz += sizeof(struct nlattr);
208
209 struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr);
210 if (__predict_false(nla == NULL))
211 return (NULL);
212 nla->nla_type = nla_type;
213 nla->nla_len = sz;
214
215 return ((void *)(nla + 1));
216}
217#define nlmsg_reserve_attr(_ns, _at, _t) ((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t))))
218
219bool nlattr_add(struct nl_writer *nw, uint16_t attr_type, uint16_t attr_len,
220 const void *data);
221
222static inline bool
223nlattr_add_raw(struct nl_writer *nw, const struct nlattr *nla_src)
224{
225 MPASS(nla_src->nla_len >= sizeof(struct nlattr));
226
227 return (nlattr_add(nw, nla_src->nla_type,
228 nla_src->nla_len - sizeof(struct nlattr),
229 (const void *)(nla_src + 1)));
230}
231
232static inline bool
233nlattr_add_bool(struct nl_writer *nw, uint16_t attrtype, bool value)
234{
235 return (nlattr_add(nw, attrtype, sizeof(bool), &value));
236}
237
238static inline bool
239nlattr_add_u8(struct nl_writer *nw, uint16_t attrtype, uint8_t value)
240{
241 return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value));
242}
243
244static inline bool
245nlattr_add_u16(struct nl_writer *nw, uint16_t attrtype, uint16_t value)
246{
247 return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value));
248}
249
250static inline bool
251nlattr_add_u32(struct nl_writer *nw, uint16_t attrtype, uint32_t value)
252{
253 return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value));
254}
255
256static inline bool
257nlattr_add_u64(struct nl_writer *nw, uint16_t attrtype, uint64_t value)
258{
259 return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value));
260}
261
262static inline bool
263nlattr_add_s8(struct nl_writer *nw, uint16_t attrtype, int8_t value)
264{
265 return (nlattr_add(nw, attrtype, sizeof(int8_t), &value));
266}
267
268static inline bool
269nlattr_add_s16(struct nl_writer *nw, uint16_t attrtype, int16_t value)
270{
271 return (nlattr_add(nw, attrtype, sizeof(int16_t), &value));
272}
273
274static inline bool
275nlattr_add_s32(struct nl_writer *nw, uint16_t attrtype, int32_t value)
276{
277 return (nlattr_add(nw, attrtype, sizeof(int32_t), &value));
278}
279
280static inline bool
281nlattr_add_s64(struct nl_writer *nw, uint16_t attrtype, int64_t value)
282{
283 return (nlattr_add(nw, attrtype, sizeof(int64_t), &value));
284}
285
286static inline bool
287nlattr_add_flag(struct nl_writer *nw, uint16_t attrtype)
288{
289 return (nlattr_add(nw, attrtype, 0, NULL));
290}
291
292static inline bool
293nlattr_add_string(struct nl_writer *nw, uint16_t attrtype, const char *str)
294{
295 return (nlattr_add(nw, attrtype, strlen(str) + 1, str));
296}
297
298static inline bool
299nlattr_add_in_addr(struct nl_writer *nw, uint16_t attrtype,
300 const struct in_addr *in)
301{
302 return (nlattr_add(nw, attrtype, sizeof(*in), in));
303}
304
305static inline bool
306nlattr_add_in6_addr(struct nl_writer *nw, uint16_t attrtype,
307 const struct in6_addr *in6)
308{
309 return (nlattr_add(nw, attrtype, sizeof(*in6), in6));
310}
311#endif
312#endif