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		} group;
54	};
55	u_int		num_messages;	/* Number of messages in the buffer */
56	int		malloc_flag;	/* M_WAITOK or M_NOWAIT */
57	bool		ignore_limit;	/* If true, ignores RCVBUF limit */
58	bool		enomem;		/* True if ENOMEM occured */
59	bool		suppress_ack;	/* If true, don't send NLMSG_ERR */
60};
61
62#define	NLMSG_SMALL	128
63#define	NLMSG_LARGE	2048
64
65/* Message and attribute writing */
66#if defined(NETLINK) || defined(NETLINK_MODULE)
67/* Provide optimized calls to the functions inside the same linking unit */
68
69bool _nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp);
70bool _nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id);
71bool _nlmsg_flush(struct nl_writer *nw);
72void _nlmsg_ignore_limit(struct nl_writer *nw);
73
74bool _nlmsg_refill_buffer(struct nl_writer *nw, u_int required_len);
75bool _nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
76    uint16_t flags, uint32_t len);
77bool _nlmsg_end(struct nl_writer *nw);
78void _nlmsg_abort(struct nl_writer *nw);
79
80bool _nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
81
82
83static inline bool
84nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp)
85{
86	return (_nlmsg_get_unicast_writer(nw, expected_size, nlp));
87}
88
89static inline bool
90nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id)
91{
92	return (_nlmsg_get_group_writer(nw, expected_size, proto, group_id));
93}
94
95static inline bool
96nlmsg_flush(struct nl_writer *nw)
97{
98	return (_nlmsg_flush(nw));
99}
100
101static inline void
102nlmsg_ignore_limit(struct nl_writer *nw)
103{
104	_nlmsg_ignore_limit(nw);
105}
106
107static inline bool
108nlmsg_refill_buffer(struct nl_writer *nw, int required_size)
109{
110	return (_nlmsg_refill_buffer(nw, required_size));
111}
112
113static inline bool
114nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
115    uint16_t flags, uint32_t len)
116{
117	return (_nlmsg_add(nw, portid, seq, type, flags, len));
118}
119
120static inline bool
121nlmsg_end(struct nl_writer *nw)
122{
123	return (_nlmsg_end(nw));
124}
125
126static inline void
127nlmsg_abort(struct nl_writer *nw)
128{
129	return (_nlmsg_abort(nw));
130}
131
132static inline bool
133nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr)
134{
135	return (_nlmsg_end_dump(nw, error, hdr));
136}
137
138#else
139/* Provide access to the functions via netlink_glue.c */
140
141bool nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp);
142bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id);
143bool nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm);
144bool nlmsg_flush(struct nl_writer *nw);
145void nlmsg_ignore_limit(struct nl_writer *nw);
146
147bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size);
148bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
149    uint16_t flags, uint32_t len);
150bool nlmsg_end(struct nl_writer *nw);
151void nlmsg_abort(struct nl_writer *nw);
152
153bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
154
155#endif /* defined(NETLINK) || defined(NETLINK_MODULE) */
156
157static inline bool
158nlmsg_reply(struct nl_writer *nw, const struct nlmsghdr *hdr, int payload_len)
159{
160	return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type,
161	    hdr->nlmsg_flags, payload_len));
162}
163
164/*
165 * KPI similar to mtodo():
166 * current (uncompleted) header is guaranteed to be contiguous,
167 *  but can be reallocated, thus pointers may need to be readjusted.
168 */
169u_int nlattr_save_offset(const struct nl_writer *nw);
170
171static inline void *
172_nlattr_restore_offset(const struct nl_writer *nw, int off)
173{
174	return ((void *)((char *)nw->hdr + off));
175}
176#define	nlattr_restore_offset(_ns, _off, _t)	((_t *)_nlattr_restore_offset(_ns, _off))
177
178static inline void
179nlattr_set_len(const struct nl_writer *nw, int off)
180{
181	struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr);
182	nla->nla_len = nlattr_save_offset(nw) - off;
183}
184
185void *nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz);
186#define nlmsg_reserve_object(_ns, _t)	((_t *)nlmsg_reserve_data_raw(_ns, sizeof(_t)))
187#define nlmsg_reserve_data(_ns, _sz, _t)	((_t *)nlmsg_reserve_data_raw(_ns, _sz))
188
189static inline int
190nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type)
191{
192	int off = nlattr_save_offset(nw);
193	struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr);
194	if (__predict_false(nla == NULL))
195		return (0);
196	nla->nla_type = nla_type;
197	return (off);
198}
199
200static inline void *
201_nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz)
202{
203	sz += sizeof(struct nlattr);
204
205	struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr);
206	if (__predict_false(nla == NULL))
207		return (NULL);
208	nla->nla_type = nla_type;
209	nla->nla_len = sz;
210
211	return ((void *)(nla + 1));
212}
213#define	nlmsg_reserve_attr(_ns, _at, _t)	((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t))))
214
215bool nlattr_add(struct nl_writer *nw, int attr_type, int attr_len,
216    const void *data);
217
218static inline bool
219nlattr_add_raw(struct nl_writer *nw, const struct nlattr *nla_src)
220{
221	int attr_len = nla_src->nla_len - sizeof(struct nlattr);
222
223	MPASS(attr_len >= 0);
224
225	return (nlattr_add(nw, nla_src->nla_type, attr_len, (const void *)(nla_src + 1)));
226}
227
228static inline bool
229nlattr_add_bool(struct nl_writer *nw, int attrtype, bool value)
230{
231	return (nlattr_add(nw, attrtype, sizeof(bool), &value));
232}
233
234static inline bool
235nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value)
236{
237	return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value));
238}
239
240static inline bool
241nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value)
242{
243	return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value));
244}
245
246static inline bool
247nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value)
248{
249	return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value));
250}
251
252static inline bool
253nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value)
254{
255	return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value));
256}
257
258static inline bool
259nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value)
260{
261	return (nlattr_add(nw, attrtype, sizeof(int8_t), &value));
262}
263
264static inline bool
265nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value)
266{
267	return (nlattr_add(nw, attrtype, sizeof(int16_t), &value));
268}
269
270static inline bool
271nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value)
272{
273	return (nlattr_add(nw, attrtype, sizeof(int32_t), &value));
274}
275
276static inline bool
277nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value)
278{
279	return (nlattr_add(nw, attrtype, sizeof(int64_t), &value));
280}
281
282static inline bool
283nlattr_add_flag(struct nl_writer *nw, int attrtype)
284{
285	return (nlattr_add(nw, attrtype, 0, NULL));
286}
287
288static inline bool
289nlattr_add_string(struct nl_writer *nw, int attrtype, const char *str)
290{
291	return (nlattr_add(nw, attrtype, strlen(str) + 1, str));
292}
293
294static inline bool
295nlattr_add_in_addr(struct nl_writer *nw, int attrtype, const struct in_addr *in)
296{
297	return (nlattr_add(nw, attrtype, sizeof(*in), in));
298}
299
300static inline bool
301nlattr_add_in6_addr(struct nl_writer *nw, int attrtype, const struct in6_addr *in6)
302{
303	return (nlattr_add(nw, attrtype, sizeof(*in6), in6));
304}
305#endif
306#endif
307