libnftnl 1.3.2
expr.c
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
4 *
5 * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
6 */
7#include "internal.h"
8
9#include <time.h>
10#include <endian.h>
11#include <stdint.h>
12#include <stdlib.h>
13#include <string.h>
14#include <errno.h>
15#include <netinet/in.h>
16
17#include <libmnl/libmnl.h>
18#include <linux/netfilter/nfnetlink.h>
19#include <linux/netfilter/nf_tables.h>
20
21#include <libnftnl/expr.h>
22
23EXPORT_SYMBOL(nftnl_expr_alloc);
24struct nftnl_expr *nftnl_expr_alloc(const char *name)
25{
26 struct nftnl_expr *expr;
27 struct expr_ops *ops;
28
29 ops = nftnl_expr_ops_lookup(name);
30 if (ops == NULL)
31 return NULL;
32
33 expr = calloc(1, sizeof(struct nftnl_expr) + ops->alloc_len);
34 if (expr == NULL)
35 return NULL;
36
37 /* Manually set expression name attribute */
38 expr->flags |= (1 << NFTNL_EXPR_NAME);
39 expr->ops = ops;
40
41 if (ops->init)
42 ops->init(expr);
43
44 return expr;
45}
46
47EXPORT_SYMBOL(nftnl_expr_free);
48void nftnl_expr_free(const struct nftnl_expr *expr)
49{
50 if (expr->ops->free)
51 expr->ops->free(expr);
52
53 xfree(expr);
54}
55
56EXPORT_SYMBOL(nftnl_expr_is_set);
57bool nftnl_expr_is_set(const struct nftnl_expr *expr, uint16_t type)
58{
59 return expr->flags & (1 << type);
60}
61
62static int __nftnl_expr_set(struct nftnl_expr *expr, uint16_t type,
63 const void *data, uint32_t data_len,
64 uint32_t byteorder)
65{
66 switch(type) {
67 case NFTNL_EXPR_NAME: /* cannot be modified */
68 return 0;
69 default:
70 if (type < NFTNL_EXPR_BASE || type > expr->ops->nftnl_max_attr)
71 return -1;
72
73 if (!expr->ops->attr_policy)
74 return -1;
75
76 if (expr->ops->attr_policy[type].maxlen &&
77 expr->ops->attr_policy[type].maxlen < data_len)
78 return -1;
79
80 if (expr->ops->set(expr, type, data, data_len, byteorder) < 0)
81 return -1;
82 }
83 expr->flags |= (1 << type);
84 return 0;
85}
86
87EXPORT_SYMBOL(nftnl_expr_set);
88int nftnl_expr_set(struct nftnl_expr *expr, uint16_t type,
89 const void *data, uint32_t data_len)
90{
91 return __nftnl_expr_set(expr, type, data, data_len, 0);
92}
93
94EXPORT_SYMBOL(nftnl_expr_set_imm);
95int nftnl_expr_set_imm(struct nftnl_expr *expr, uint16_t type,
96 const void *data, uint32_t data_len, uint32_t byteorder)
97{
98 return __nftnl_expr_set(expr, type, data, data_len, byteorder);
99}
100
101EXPORT_SYMBOL(nftnl_expr_set_u8);
102void
103nftnl_expr_set_u8(struct nftnl_expr *expr, uint16_t type, uint8_t data)
104{
105 nftnl_expr_set(expr, type, &data, sizeof(uint8_t));
106}
107
108EXPORT_SYMBOL(nftnl_expr_set_u16);
109void
110nftnl_expr_set_u16(struct nftnl_expr *expr, uint16_t type, uint16_t data)
111{
112 nftnl_expr_set(expr, type, &data, sizeof(uint16_t));
113}
114
115EXPORT_SYMBOL(nftnl_expr_set_u32);
116void
117nftnl_expr_set_u32(struct nftnl_expr *expr, uint16_t type, uint32_t data)
118{
119 nftnl_expr_set(expr, type, &data, sizeof(uint32_t));
120}
121
122EXPORT_SYMBOL(nftnl_expr_set_u64);
123void
124nftnl_expr_set_u64(struct nftnl_expr *expr, uint16_t type, uint64_t data)
125{
126 nftnl_expr_set(expr, type, &data, sizeof(uint64_t));
127}
128
129EXPORT_SYMBOL(nftnl_expr_set_str);
130int nftnl_expr_set_str(struct nftnl_expr *expr, uint16_t type, const char *str)
131{
132 return nftnl_expr_set(expr, type, str, strlen(str) + 1);
133}
134
135EXPORT_SYMBOL(nftnl_expr_get);
136const void *nftnl_expr_get(const struct nftnl_expr *expr,
137 uint16_t type, uint32_t *data_len)
138{
139 const void *ret;
140
141 if (!(expr->flags & (1 << type)))
142 return NULL;
143
144 switch(type) {
145 case NFTNL_EXPR_NAME:
146 *data_len = strlen(expr->ops->name) + 1;
147 ret = expr->ops->name;
148 break;
149 default:
150 ret = expr->ops->get(expr, type, data_len);
151 break;
152 }
153
154 return ret;
155}
156
157EXPORT_SYMBOL(nftnl_expr_get_u8);
158uint8_t nftnl_expr_get_u8(const struct nftnl_expr *expr, uint16_t type)
159{
160 const void *data;
161 uint32_t data_len;
162
163 data = nftnl_expr_get(expr, type, &data_len);
164 if (data == NULL)
165 return 0;
166
167 if (data_len != sizeof(uint8_t))
168 return 0;
169
170 return *((uint8_t *)data);
171}
172
173EXPORT_SYMBOL(nftnl_expr_get_u16);
174uint16_t nftnl_expr_get_u16(const struct nftnl_expr *expr, uint16_t type)
175{
176 const void *data;
177 uint32_t data_len;
178
179 data = nftnl_expr_get(expr, type, &data_len);
180 if (data == NULL)
181 return 0;
182
183 if (data_len != sizeof(uint16_t))
184 return 0;
185
186 return *((uint16_t *)data);
187}
188
189EXPORT_SYMBOL(nftnl_expr_get_u32);
190uint32_t nftnl_expr_get_u32(const struct nftnl_expr *expr, uint16_t type)
191{
192 const void *data;
193 uint32_t data_len;
194
195 data = nftnl_expr_get(expr, type, &data_len);
196 if (data == NULL)
197 return 0;
198
199 if (data_len != sizeof(uint32_t))
200 return 0;
201
202 return *((uint32_t *)data);
203}
204
205EXPORT_SYMBOL(nftnl_expr_get_u64);
206uint64_t nftnl_expr_get_u64(const struct nftnl_expr *expr, uint16_t type)
207{
208 const void *data;
209 uint32_t data_len;
210
211 data = nftnl_expr_get(expr, type, &data_len);
212 if (data == NULL)
213 return 0;
214
215 if (data_len != sizeof(uint64_t))
216 return 0;
217
218 return *((uint64_t *)data);
219}
220
221EXPORT_SYMBOL(nftnl_expr_get_str);
222const char *nftnl_expr_get_str(const struct nftnl_expr *expr, uint16_t type)
223{
224 uint32_t data_len;
225
226 return (const char *)nftnl_expr_get(expr, type, &data_len);
227}
228
229EXPORT_SYMBOL(nftnl_expr_build_payload);
230void nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
231{
232 struct nlattr *nest;
233
234 mnl_attr_put_strz(nlh, NFTA_EXPR_NAME, expr->ops->name);
235
236 if (!expr->ops->build)
237 return;
238
239 nest = mnl_attr_nest_start(nlh, NFTA_EXPR_DATA);
240 expr->ops->build(nlh, expr);
241 mnl_attr_nest_end(nlh, nest);
242}
243
244static int nftnl_rule_parse_expr_cb(const struct nlattr *attr, void *data)
245{
246 const struct nlattr **tb = data;
247 int type = mnl_attr_get_type(attr);
248
249 if (mnl_attr_type_valid(attr, NFTA_EXPR_MAX) < 0)
250 return MNL_CB_OK;
251
252 switch (type) {
253 case NFTA_EXPR_NAME:
254 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
255 abi_breakage();
256 break;
257 case NFTA_EXPR_DATA:
258 if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
259 abi_breakage();
260 break;
261 }
262
263 tb[type] = attr;
264 return MNL_CB_OK;
265}
266
267struct nftnl_expr *nftnl_expr_parse(struct nlattr *attr)
268{
269 struct nlattr *tb[NFTA_EXPR_MAX+1] = {};
270 struct nftnl_expr *expr;
271
272 if (mnl_attr_parse_nested(attr, nftnl_rule_parse_expr_cb, tb) < 0)
273 goto err1;
274
275 expr = nftnl_expr_alloc(mnl_attr_get_str(tb[NFTA_EXPR_NAME]));
276 if (expr == NULL)
277 goto err1;
278
279 if (tb[NFTA_EXPR_DATA] &&
280 expr->ops->parse &&
281 expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0)
282 goto err2;
283
284 return expr;
285
286err2:
287 xfree(expr);
288err1:
289 return NULL;
290}
291
292EXPORT_SYMBOL(nftnl_expr_snprintf);
293int nftnl_expr_snprintf(char *buf, size_t remain, const struct nftnl_expr *expr,
294 uint32_t type, uint32_t flags)
295{
296 int ret;
297 unsigned int offset = 0;
298
299 if (remain)
300 buf[0] = '\0';
301
302 if (!expr->ops->output || type != NFTNL_OUTPUT_DEFAULT)
303 return 0;
304
305 ret = expr->ops->output(buf + offset, remain, flags, expr);
306 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
307
308 return offset;
309}
310
311static int nftnl_expr_do_snprintf(char *buf, size_t size, const void *e,
312 uint32_t cmd, uint32_t type, uint32_t flags)
313{
314 return nftnl_expr_snprintf(buf, size, e, type, flags);
315}
316
317EXPORT_SYMBOL(nftnl_expr_fprintf);
318int nftnl_expr_fprintf(FILE *fp, const struct nftnl_expr *expr, uint32_t type,
319 uint32_t flags)
320{
321 return nftnl_fprintf(fp, expr, NFTNL_CMD_UNSPEC, type, flags,
322 nftnl_expr_do_snprintf);
323}
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