master
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2022 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#ifndef _NETLINK_NETLINK_MESSAGE_PARSER_H_
29#define _NETLINK_NETLINK_MESSAGE_PARSER_H_
30
31#ifdef _KERNEL
32
33#include <sys/bitset.h>
34
35/*
36 * It is not meant to be included directly
37 */
38
39/* Parsing state */
40struct linear_buffer {
41 char *base; /* Base allocated memory pointer */
42 uint32_t offset; /* Currently used offset */
43 uint32_t size; /* Total buffer size */
44} __aligned(_Alignof(__max_align_t));
45
46static inline void *
47lb_alloc(struct linear_buffer *lb, int len)
48{
49 len = roundup2(len, _Alignof(__max_align_t));
50 if (lb->offset + len > lb->size)
51 return (NULL);
52 void *data = (void *)(lb->base + lb->offset);
53 lb->offset += len;
54 return (data);
55}
56
57static inline void
58lb_clear(struct linear_buffer *lb)
59{
60 memset(lb->base, 0, lb->size);
61 lb->offset = 0;
62}
63
64#define NL_MAX_ERROR_BUF 128
65#define SCRATCH_BUFFER_SIZE (1024 + NL_MAX_ERROR_BUF)
66struct nl_pstate {
67 struct linear_buffer lb; /* Per-message scratch buffer */
68 struct nlpcb *nlp; /* Originator socket */
69 struct nl_writer *nw; /* Message writer to use */
70 struct nlmsghdr *hdr; /* Current parsed message header */
71 uint32_t err_off; /* error offset from hdr start */
72 int error; /* last operation error */
73 char *err_msg; /* Description of last error */
74 struct nlattr *cookie; /* NLA to return to the userspace */
75 bool strict; /* Strict parsing required */
76};
77
78static inline void *
79npt_alloc(struct nl_pstate *npt, int len)
80{
81 return (lb_alloc(&npt->lb, len));
82}
83#define npt_alloc_sockaddr(_npt, _len) ((struct sockaddr *)(npt_alloc(_npt, _len)))
84
85typedef int parse_field_f(void *hdr, struct nl_pstate *npt,
86 void *target);
87struct nlfield_parser {
88 uint16_t off_in;
89 uint16_t off_out;
90 parse_field_f *cb;
91};
92static const struct nlfield_parser nlf_p_empty[] = {};
93
94int nlf_get_ifp(void *src, struct nl_pstate *npt, void *target);
95int nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target);
96int nlf_get_u8(void *src, struct nl_pstate *npt, void *target);
97int nlf_get_u16(void *src, struct nl_pstate *npt, void *target);
98int nlf_get_u32(void *src, struct nl_pstate *npt, void *target);
99int nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target);
100
101
102struct nlattr_parser;
103typedef int parse_attr_f(struct nlattr *attr, struct nl_pstate *npt,
104 const void *arg, void *target);
105struct nlattr_parser {
106 uint16_t type; /* Attribute type */
107 uint16_t off; /* field offset in the target structure */
108 parse_attr_f *cb; /* parser function to call */
109 const void *arg;
110};
111
112typedef bool strict_parser_f(void *hdr, struct nl_pstate *npt);
113typedef bool post_parser_f(void *parsed_attrs, struct nl_pstate *npt);
114
115struct nlhdr_parser {
116 int nl_hdr_off; /* aligned netlink header size */
117 int out_hdr_off; /* target header size */
118 int fp_size;
119 int np_size;
120 const struct nlfield_parser *fp; /* array of header field parsers */
121 const struct nlattr_parser *np; /* array of attribute parsers */
122 strict_parser_f *sp; /* Pre-parse strict validation function */
123 post_parser_f *post_parse;
124};
125
126#define NL_DECLARE_PARSER_EXT(_name, _t, _sp, _fp, _np, _pp) \
127static const struct nlhdr_parser _name = { \
128 .nl_hdr_off = sizeof(_t), \
129 .fp = &((_fp)[0]), \
130 .np = &((_np)[0]), \
131 .fp_size = NL_ARRAY_LEN(_fp), \
132 .np_size = NL_ARRAY_LEN(_np), \
133 .sp = _sp, \
134 .post_parse = _pp, \
135}
136
137#define NL_DECLARE_PARSER(_name, _t, _fp, _np) \
138 NL_DECLARE_PARSER_EXT(_name, _t, NULL, _fp, _np, NULL)
139
140#define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np) \
141 NL_DECLARE_PARSER_EXT(_name, _t, _sp, _fp, _np, NULL)
142
143#define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \
144static const struct nlhdr_parser _name = { \
145 .nl_hdr_off = sizeof(_t), \
146 .out_hdr_off = sizeof(_o), \
147 .fp = &((_fp)[0]), \
148 .np = &((_np)[0]), \
149 .fp_size = NL_ARRAY_LEN(_fp), \
150 .np_size = NL_ARRAY_LEN(_np), \
151}
152
153#define NL_DECLARE_ATTR_PARSER(_name, _np) \
154static const struct nlhdr_parser _name = { \
155 .np = &((_np)[0]), \
156 .np_size = NL_ARRAY_LEN(_np), \
157}
158
159#define NL_ATTR_BMASK_SIZE 128
160BITSET_DEFINE(nlattr_bmask, NL_ATTR_BMASK_SIZE);
161
162void nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm);
163bool nl_has_attr(const struct nlattr_bmask *bm, unsigned int nla_type);
164
165int nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps,
166 int pslen, struct nl_pstate *npt, void *target);
167
168int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt,
169 const void *arg, void *target);
170int nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt,
171 const void *arg, void *target);
172int nlattr_get_uint8(struct nlattr *nla, struct nl_pstate *npt,
173 const void *arg, void *target);
174int nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt,
175 const void *arg, void *target);
176int nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt,
177 const void *arg, void *target);
178int nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt,
179 const void *arg, void *target);
180int nlattr_get_in_addr(struct nlattr *nla, struct nl_pstate *npt,
181 const void *arg, void *target);
182int nlattr_get_in6_addr(struct nlattr *nla, struct nl_pstate *npt,
183 const void *arg, void *target);
184int nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt,
185 const void *arg, void *target);
186int nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt,
187 const void *arg, void *target);
188int nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt,
189 const void *arg, void *target);
190int nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt,
191 const void *arg, void *target);
192int nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt,
193 const void *arg, void *target);
194int nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt,
195 const void *arg, void *target);
196int nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt,
197 const void *arg, void *target);
198
199bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...);
200
201#define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \
202 nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \
203 NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \
204}
205
206bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off);
207
208void nlmsg_report_cookie(struct nl_pstate *npt, struct nlattr *nla);
209void nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val);
210
211/*
212 * Have it inline so compiler can optimize field accesses into
213 * the list of direct function calls without iteration.
214 */
215static inline int
216nl_parse_header(void *hdr, int len, const struct nlhdr_parser *parser,
217 struct nl_pstate *npt, void *target)
218{
219 int error;
220
221 if (__predict_false(len < parser->nl_hdr_off)) {
222 if (npt->strict) {
223 nlmsg_report_err_msg(npt, "header too short: expected %d, got %d",
224 parser->nl_hdr_off, len);
225 return (EINVAL);
226 }
227
228 /* Compat with older applications: pretend there's a full header */
229 void *tmp_hdr = npt_alloc(npt, parser->nl_hdr_off);
230 if (tmp_hdr == NULL)
231 return (EINVAL);
232 memcpy(tmp_hdr, hdr, len);
233 hdr = tmp_hdr;
234 len = parser->nl_hdr_off;
235 }
236
237 if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt))
238 return (EINVAL);
239
240 /* Extract fields first */
241 for (int i = 0; i < parser->fp_size; i++) {
242 const struct nlfield_parser *fp = &parser->fp[i];
243 void *src = (char *)hdr + fp->off_in;
244 void *dst = (char *)target + fp->off_out;
245
246 error = fp->cb(src, npt, dst);
247 if (error != 0)
248 return (error);
249 }
250
251 struct nlattr *nla_head = (struct nlattr *)((char *)hdr + parser->nl_hdr_off);
252 error = nl_parse_attrs_raw(nla_head, len - parser->nl_hdr_off, parser->np,
253 parser->np_size, npt, target);
254
255 if (parser->post_parse != NULL && error == 0) {
256 if (!parser->post_parse(target, npt))
257 return (EINVAL);
258 }
259
260 return (error);
261}
262
263static inline int
264nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser,
265 struct nl_pstate *npt, void *target)
266{
267 struct nlattr *nla_head = (struct nlattr *)NLA_DATA(nla);
268
269 return (nl_parse_attrs_raw(nla_head, NLA_DATA_LEN(nla), parser->np,
270 parser->np_size, npt, target));
271}
272
273/*
274 * Checks that attributes are sorted by attribute type.
275 */
276static inline void
277nl_verify_parsers(const struct nlhdr_parser **parser, int count)
278{
279#ifdef INVARIANTS
280 for (int i = 0; i < count; i++) {
281 const struct nlhdr_parser *p = parser[i];
282 int attr_type = 0;
283 for (int j = 0; j < p->np_size; j++) {
284 MPASS(p->np[j].type > attr_type);
285 attr_type = p->np[j].type;
286 }
287 }
288#endif
289}
290void nl_verify_parsers(const struct nlhdr_parser **parser, int count);
291#define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), NL_ARRAY_LEN(_p))
292
293static inline int
294nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
295 struct nl_pstate *npt, void *target)
296{
297 return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target));
298}
299
300static inline void
301nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
302 struct nlattr_bmask *bm)
303{
304 struct nlattr *nla_head;
305
306 nla_head = (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off);
307 int len = hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off;
308
309 nl_get_attrs_bmask_raw(nla_head, len, bm);
310}
311
312#endif
313#endif