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
40 struct nl_buf;
41 struct nl_writer;
42 typedef bool nl_writer_cb(struct nl_writer *nw);
43
44 struct 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
69 bool _nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp);
70 bool _nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id);
71 bool _nlmsg_flush(struct nl_writer *nw);
72 void _nlmsg_ignore_limit(struct nl_writer *nw);
73
74 bool _nlmsg_refill_buffer(struct nl_writer *nw, u_int required_len);
75 bool _nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
76 uint16_t flags, uint32_t len);
77 bool _nlmsg_end(struct nl_writer *nw);
78 void _nlmsg_abort(struct nl_writer *nw);
79
80 bool _nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
81
82
83 static inline bool
nlmsg_get_unicast_writer(struct nl_writer * nw,int expected_size,struct nlpcb * nlp)84 nlmsg_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
89 static inline bool
nlmsg_get_group_writer(struct nl_writer * nw,int expected_size,int proto,int group_id)90 nlmsg_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
95 static inline bool
nlmsg_flush(struct nl_writer * nw)96 nlmsg_flush(struct nl_writer *nw)
97 {
98 return (_nlmsg_flush(nw));
99 }
100
101 static inline void
nlmsg_ignore_limit(struct nl_writer * nw)102 nlmsg_ignore_limit(struct nl_writer *nw)
103 {
104 _nlmsg_ignore_limit(nw);
105 }
106
107 static inline bool
nlmsg_refill_buffer(struct nl_writer * nw,int required_size)108 nlmsg_refill_buffer(struct nl_writer *nw, int required_size)
109 {
110 return (_nlmsg_refill_buffer(nw, required_size));
111 }
112
113 static inline bool
nlmsg_add(struct nl_writer * nw,uint32_t portid,uint32_t seq,uint16_t type,uint16_t flags,uint32_t len)114 nlmsg_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
120 static inline bool
nlmsg_end(struct nl_writer * nw)121 nlmsg_end(struct nl_writer *nw)
122 {
123 return (_nlmsg_end(nw));
124 }
125
126 static inline void
nlmsg_abort(struct nl_writer * nw)127 nlmsg_abort(struct nl_writer *nw)
128 {
129 return (_nlmsg_abort(nw));
130 }
131
132 static inline bool
nlmsg_end_dump(struct nl_writer * nw,int error,struct nlmsghdr * hdr)133 nlmsg_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
141 bool nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp);
142 bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id);
143 bool nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm);
144 bool nlmsg_flush(struct nl_writer *nw);
145 void nlmsg_ignore_limit(struct nl_writer *nw);
146
147 bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size);
148 bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
149 uint16_t flags, uint32_t len);
150 bool nlmsg_end(struct nl_writer *nw);
151 void nlmsg_abort(struct nl_writer *nw);
152
153 bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
154
155 #endif /* defined(NETLINK) || defined(NETLINK_MODULE) */
156
157 static inline bool
nlmsg_reply(struct nl_writer * nw,const struct nlmsghdr * hdr,int payload_len)158 nlmsg_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 */
169 u_int nlattr_save_offset(const struct nl_writer *nw);
170
171 static inline void *
_nlattr_restore_offset(const struct nl_writer * nw,int off)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
178 static inline void
nlattr_set_len(const struct nl_writer * nw,int off)179 nlattr_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
185 void *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
189 static inline int
nlattr_add_nested(struct nl_writer * nw,uint16_t nla_type)190 nlattr_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
200 static inline void *
_nlmsg_reserve_attr(struct nl_writer * nw,uint16_t nla_type,uint16_t sz)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
215 bool nlattr_add(struct nl_writer *nw, int attr_type, int attr_len,
216 const void *data);
217
218 static inline bool
nlattr_add_raw(struct nl_writer * nw,const struct nlattr * nla_src)219 nlattr_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
228 static inline bool
nlattr_add_bool(struct nl_writer * nw,int attrtype,bool value)229 nlattr_add_bool(struct nl_writer *nw, int attrtype, bool value)
230 {
231 return (nlattr_add(nw, attrtype, sizeof(bool), &value));
232 }
233
234 static inline bool
nlattr_add_u8(struct nl_writer * nw,int attrtype,uint8_t value)235 nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value)
236 {
237 return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value));
238 }
239
240 static inline bool
nlattr_add_u16(struct nl_writer * nw,int attrtype,uint16_t value)241 nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value)
242 {
243 return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value));
244 }
245
246 static inline bool
nlattr_add_u32(struct nl_writer * nw,int attrtype,uint32_t value)247 nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value)
248 {
249 return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value));
250 }
251
252 static inline bool
nlattr_add_u64(struct nl_writer * nw,int attrtype,uint64_t value)253 nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value)
254 {
255 return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value));
256 }
257
258 static inline bool
nlattr_add_s8(struct nl_writer * nw,int attrtype,int8_t value)259 nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value)
260 {
261 return (nlattr_add(nw, attrtype, sizeof(int8_t), &value));
262 }
263
264 static inline bool
nlattr_add_s16(struct nl_writer * nw,int attrtype,int16_t value)265 nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value)
266 {
267 return (nlattr_add(nw, attrtype, sizeof(int16_t), &value));
268 }
269
270 static inline bool
nlattr_add_s32(struct nl_writer * nw,int attrtype,int32_t value)271 nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value)
272 {
273 return (nlattr_add(nw, attrtype, sizeof(int32_t), &value));
274 }
275
276 static inline bool
nlattr_add_s64(struct nl_writer * nw,int attrtype,int64_t value)277 nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value)
278 {
279 return (nlattr_add(nw, attrtype, sizeof(int64_t), &value));
280 }
281
282 static inline bool
nlattr_add_flag(struct nl_writer * nw,int attrtype)283 nlattr_add_flag(struct nl_writer *nw, int attrtype)
284 {
285 return (nlattr_add(nw, attrtype, 0, NULL));
286 }
287
288 static inline bool
nlattr_add_string(struct nl_writer * nw,int attrtype,const char * str)289 nlattr_add_string(struct nl_writer *nw, int attrtype, const char *str)
290 {
291 return (nlattr_add(nw, attrtype, strlen(str) + 1, str));
292 }
293
294 static inline bool
nlattr_add_in_addr(struct nl_writer * nw,int attrtype,const struct in_addr * in)295 nlattr_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
300 static inline bool
nlattr_add_in6_addr(struct nl_writer * nw,int attrtype,const struct in6_addr * in6)301 nlattr_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