libnftnl 1.2.9
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
62EXPORT_SYMBOL(nftnl_expr_set);
63int nftnl_expr_set(struct nftnl_expr *expr, uint16_t type,
64 const void *data, uint32_t data_len)
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) < 0)
81 return -1;
82 }
83 expr->flags |= (1 << type);
84 return 0;
85}
86
87EXPORT_SYMBOL(nftnl_expr_set_u8);
88void
89nftnl_expr_set_u8(struct nftnl_expr *expr, uint16_t type, uint8_t data)
90{
91 nftnl_expr_set(expr, type, &data, sizeof(uint8_t));
92}
93
94EXPORT_SYMBOL(nftnl_expr_set_u16);
95void
96nftnl_expr_set_u16(struct nftnl_expr *expr, uint16_t type, uint16_t data)
97{
98 nftnl_expr_set(expr, type, &data, sizeof(uint16_t));
99}
100
101EXPORT_SYMBOL(nftnl_expr_set_u32);
102void
103nftnl_expr_set_u32(struct nftnl_expr *expr, uint16_t type, uint32_t data)
104{
105 nftnl_expr_set(expr, type, &data, sizeof(uint32_t));
106}
107
108EXPORT_SYMBOL(nftnl_expr_set_u64);
109void
110nftnl_expr_set_u64(struct nftnl_expr *expr, uint16_t type, uint64_t data)
111{
112 nftnl_expr_set(expr, type, &data, sizeof(uint64_t));
113}
114
115EXPORT_SYMBOL(nftnl_expr_set_str);
116int nftnl_expr_set_str(struct nftnl_expr *expr, uint16_t type, const char *str)
117{
118 return nftnl_expr_set(expr, type, str, strlen(str) + 1);
119}
120
121EXPORT_SYMBOL(nftnl_expr_get);
122const void *nftnl_expr_get(const struct nftnl_expr *expr,
123 uint16_t type, uint32_t *data_len)
124{
125 const void *ret;
126
127 if (!(expr->flags & (1 << type)))
128 return NULL;
129
130 switch(type) {
131 case NFTNL_EXPR_NAME:
132 *data_len = strlen(expr->ops->name) + 1;
133 ret = expr->ops->name;
134 break;
135 default:
136 ret = expr->ops->get(expr, type, data_len);
137 break;
138 }
139
140 return ret;
141}
142
143EXPORT_SYMBOL(nftnl_expr_get_u8);
144uint8_t nftnl_expr_get_u8(const struct nftnl_expr *expr, uint16_t type)
145{
146 const void *data;
147 uint32_t data_len;
148
149 data = nftnl_expr_get(expr, type, &data_len);
150 if (data == NULL)
151 return 0;
152
153 if (data_len != sizeof(uint8_t))
154 return 0;
155
156 return *((uint8_t *)data);
157}
158
159EXPORT_SYMBOL(nftnl_expr_get_u16);
160uint16_t nftnl_expr_get_u16(const struct nftnl_expr *expr, uint16_t type)
161{
162 const void *data;
163 uint32_t data_len;
164
165 data = nftnl_expr_get(expr, type, &data_len);
166 if (data == NULL)
167 return 0;
168
169 if (data_len != sizeof(uint16_t))
170 return 0;
171
172 return *((uint16_t *)data);
173}
174
175EXPORT_SYMBOL(nftnl_expr_get_u32);
176uint32_t nftnl_expr_get_u32(const struct nftnl_expr *expr, uint16_t type)
177{
178 const void *data;
179 uint32_t data_len;
180
181 data = nftnl_expr_get(expr, type, &data_len);
182 if (data == NULL)
183 return 0;
184
185 if (data_len != sizeof(uint32_t))
186 return 0;
187
188 return *((uint32_t *)data);
189}
190
191EXPORT_SYMBOL(nftnl_expr_get_u64);
192uint64_t nftnl_expr_get_u64(const struct nftnl_expr *expr, uint16_t type)
193{
194 const void *data;
195 uint32_t data_len;
196
197 data = nftnl_expr_get(expr, type, &data_len);
198 if (data == NULL)
199 return 0;
200
201 if (data_len != sizeof(uint64_t))
202 return 0;
203
204 return *((uint64_t *)data);
205}
206
207EXPORT_SYMBOL(nftnl_expr_get_str);
208const char *nftnl_expr_get_str(const struct nftnl_expr *expr, uint16_t type)
209{
210 uint32_t data_len;
211
212 return (const char *)nftnl_expr_get(expr, type, &data_len);
213}
214
215EXPORT_SYMBOL(nftnl_expr_build_payload);
216void nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
217{
218 struct nlattr *nest;
219
220 mnl_attr_put_strz(nlh, NFTA_EXPR_NAME, expr->ops->name);
221
222 if (!expr->ops->build)
223 return;
224
225 nest = mnl_attr_nest_start(nlh, NFTA_EXPR_DATA);
226 expr->ops->build(nlh, expr);
227 mnl_attr_nest_end(nlh, nest);
228}
229
230static int nftnl_rule_parse_expr_cb(const struct nlattr *attr, void *data)
231{
232 const struct nlattr **tb = data;
233 int type = mnl_attr_get_type(attr);
234
235 if (mnl_attr_type_valid(attr, NFTA_EXPR_MAX) < 0)
236 return MNL_CB_OK;
237
238 switch (type) {
239 case NFTA_EXPR_NAME:
240 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
241 abi_breakage();
242 break;
243 case NFTA_EXPR_DATA:
244 if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
245 abi_breakage();
246 break;
247 }
248
249 tb[type] = attr;
250 return MNL_CB_OK;
251}
252
253struct nftnl_expr *nftnl_expr_parse(struct nlattr *attr)
254{
255 struct nlattr *tb[NFTA_EXPR_MAX+1] = {};
256 struct nftnl_expr *expr;
257
258 if (mnl_attr_parse_nested(attr, nftnl_rule_parse_expr_cb, tb) < 0)
259 goto err1;
260
261 expr = nftnl_expr_alloc(mnl_attr_get_str(tb[NFTA_EXPR_NAME]));
262 if (expr == NULL)
263 goto err1;
264
265 if (tb[NFTA_EXPR_DATA] &&
266 expr->ops->parse &&
267 expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0)
268 goto err2;
269
270 return expr;
271
272err2:
273 xfree(expr);
274err1:
275 return NULL;
276}
277
278EXPORT_SYMBOL(nftnl_expr_snprintf);
279int nftnl_expr_snprintf(char *buf, size_t remain, const struct nftnl_expr *expr,
280 uint32_t type, uint32_t flags)
281{
282 int ret;
283 unsigned int offset = 0;
284
285 if (remain)
286 buf[0] = '\0';
287
288 if (!expr->ops->output || type != NFTNL_OUTPUT_DEFAULT)
289 return 0;
290
291 ret = expr->ops->output(buf + offset, remain, flags, expr);
292 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
293
294 return offset;
295}
296
297static int nftnl_expr_do_snprintf(char *buf, size_t size, const void *e,
298 uint32_t cmd, uint32_t type, uint32_t flags)
299{
300 return nftnl_expr_snprintf(buf, size, e, type, flags);
301}
302
303EXPORT_SYMBOL(nftnl_expr_fprintf);
304int nftnl_expr_fprintf(FILE *fp, const struct nftnl_expr *expr, uint32_t type,
305 uint32_t flags)
306{
307 return nftnl_fprintf(fp, expr, NFTNL_CMD_UNSPEC, type, flags,
308 nftnl_expr_do_snprintf);
309}