libnftnl 1.2.6
expr.c
1/*
2 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published
6 * by the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
10 */
11#include "internal.h"
12
13#include <time.h>
14#include <endian.h>
15#include <stdint.h>
16#include <stdlib.h>
17#include <string.h>
18#include <errno.h>
19#include <netinet/in.h>
20
21#include <libmnl/libmnl.h>
22#include <linux/netfilter/nfnetlink.h>
23#include <linux/netfilter/nf_tables.h>
24
25#include <libnftnl/expr.h>
26
27EXPORT_SYMBOL(nftnl_expr_alloc);
28struct nftnl_expr *nftnl_expr_alloc(const char *name)
29{
30 struct nftnl_expr *expr;
31 struct expr_ops *ops;
32
33 ops = nftnl_expr_ops_lookup(name);
34 if (ops == NULL)
35 return NULL;
36
37 expr = calloc(1, sizeof(struct nftnl_expr) + ops->alloc_len);
38 if (expr == NULL)
39 return NULL;
40
41 /* Manually set expression name attribute */
42 expr->flags |= (1 << NFTNL_EXPR_NAME);
43 expr->ops = ops;
44
45 if (ops->init)
46 ops->init(expr);
47
48 return expr;
49}
50
51EXPORT_SYMBOL(nftnl_expr_free);
52void nftnl_expr_free(const struct nftnl_expr *expr)
53{
54 if (expr->ops->free)
55 expr->ops->free(expr);
56
57 xfree(expr);
58}
59
60EXPORT_SYMBOL(nftnl_expr_is_set);
61bool nftnl_expr_is_set(const struct nftnl_expr *expr, uint16_t type)
62{
63 return expr->flags & (1 << type);
64}
65
66EXPORT_SYMBOL(nftnl_expr_set);
67int nftnl_expr_set(struct nftnl_expr *expr, uint16_t type,
68 const void *data, uint32_t data_len)
69{
70 switch(type) {
71 case NFTNL_EXPR_NAME: /* cannot be modified */
72 return 0;
73 default:
74 if (expr->ops->set(expr, type, data, data_len) < 0)
75 return -1;
76 }
77 expr->flags |= (1 << type);
78 return 0;
79}
80
81EXPORT_SYMBOL(nftnl_expr_set_u8);
82void
83nftnl_expr_set_u8(struct nftnl_expr *expr, uint16_t type, uint8_t data)
84{
85 nftnl_expr_set(expr, type, &data, sizeof(uint8_t));
86}
87
88EXPORT_SYMBOL(nftnl_expr_set_u16);
89void
90nftnl_expr_set_u16(struct nftnl_expr *expr, uint16_t type, uint16_t data)
91{
92 nftnl_expr_set(expr, type, &data, sizeof(uint16_t));
93}
94
95EXPORT_SYMBOL(nftnl_expr_set_u32);
96void
97nftnl_expr_set_u32(struct nftnl_expr *expr, uint16_t type, uint32_t data)
98{
99 nftnl_expr_set(expr, type, &data, sizeof(uint32_t));
100}
101
102EXPORT_SYMBOL(nftnl_expr_set_u64);
103void
104nftnl_expr_set_u64(struct nftnl_expr *expr, uint16_t type, uint64_t data)
105{
106 nftnl_expr_set(expr, type, &data, sizeof(uint64_t));
107}
108
109EXPORT_SYMBOL(nftnl_expr_set_str);
110int nftnl_expr_set_str(struct nftnl_expr *expr, uint16_t type, const char *str)
111{
112 return nftnl_expr_set(expr, type, str, strlen(str) + 1);
113}
114
115EXPORT_SYMBOL(nftnl_expr_get);
116const void *nftnl_expr_get(const struct nftnl_expr *expr,
117 uint16_t type, uint32_t *data_len)
118{
119 const void *ret;
120
121 if (!(expr->flags & (1 << type)))
122 return NULL;
123
124 switch(type) {
125 case NFTNL_EXPR_NAME:
126 *data_len = strlen(expr->ops->name) + 1;
127 ret = expr->ops->name;
128 break;
129 default:
130 ret = expr->ops->get(expr, type, data_len);
131 break;
132 }
133
134 return ret;
135}
136
137EXPORT_SYMBOL(nftnl_expr_get_u8);
138uint8_t nftnl_expr_get_u8(const struct nftnl_expr *expr, uint16_t type)
139{
140 const void *data;
141 uint32_t data_len;
142
143 data = nftnl_expr_get(expr, type, &data_len);
144 if (data == NULL)
145 return 0;
146
147 if (data_len != sizeof(uint8_t))
148 return 0;
149
150 return *((uint8_t *)data);
151}
152
153EXPORT_SYMBOL(nftnl_expr_get_u16);
154uint16_t nftnl_expr_get_u16(const struct nftnl_expr *expr, uint16_t type)
155{
156 const void *data;
157 uint32_t data_len;
158
159 data = nftnl_expr_get(expr, type, &data_len);
160 if (data == NULL)
161 return 0;
162
163 if (data_len != sizeof(uint16_t))
164 return 0;
165
166 return *((uint16_t *)data);
167}
168
169EXPORT_SYMBOL(nftnl_expr_get_u32);
170uint32_t nftnl_expr_get_u32(const struct nftnl_expr *expr, uint16_t type)
171{
172 const void *data;
173 uint32_t data_len;
174
175 data = nftnl_expr_get(expr, type, &data_len);
176 if (data == NULL)
177 return 0;
178
179 if (data_len != sizeof(uint32_t))
180 return 0;
181
182 return *((uint32_t *)data);
183}
184
185EXPORT_SYMBOL(nftnl_expr_get_u64);
186uint64_t nftnl_expr_get_u64(const struct nftnl_expr *expr, uint16_t type)
187{
188 const void *data;
189 uint32_t data_len;
190
191 data = nftnl_expr_get(expr, type, &data_len);
192 if (data == NULL)
193 return 0;
194
195 if (data_len != sizeof(uint64_t))
196 return 0;
197
198 return *((uint64_t *)data);
199}
200
201EXPORT_SYMBOL(nftnl_expr_get_str);
202const char *nftnl_expr_get_str(const struct nftnl_expr *expr, uint16_t type)
203{
204 uint32_t data_len;
205
206 return (const char *)nftnl_expr_get(expr, type, &data_len);
207}
208
209EXPORT_SYMBOL(nftnl_expr_build_payload);
210void nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
211{
212 struct nlattr *nest;
213
214 mnl_attr_put_strz(nlh, NFTA_EXPR_NAME, expr->ops->name);
215
216 if (!expr->ops->build)
217 return;
218
219 nest = mnl_attr_nest_start(nlh, NFTA_EXPR_DATA);
220 expr->ops->build(nlh, expr);
221 mnl_attr_nest_end(nlh, nest);
222}
223
224static int nftnl_rule_parse_expr_cb(const struct nlattr *attr, void *data)
225{
226 const struct nlattr **tb = data;
227 int type = mnl_attr_get_type(attr);
228
229 if (mnl_attr_type_valid(attr, NFTA_EXPR_MAX) < 0)
230 return MNL_CB_OK;
231
232 switch (type) {
233 case NFTA_EXPR_NAME:
234 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
235 abi_breakage();
236 break;
237 case NFTA_EXPR_DATA:
238 if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
239 abi_breakage();
240 break;
241 }
242
243 tb[type] = attr;
244 return MNL_CB_OK;
245}
246
247struct nftnl_expr *nftnl_expr_parse(struct nlattr *attr)
248{
249 struct nlattr *tb[NFTA_EXPR_MAX+1] = {};
250 struct nftnl_expr *expr;
251
252 if (mnl_attr_parse_nested(attr, nftnl_rule_parse_expr_cb, tb) < 0)
253 goto err1;
254
255 expr = nftnl_expr_alloc(mnl_attr_get_str(tb[NFTA_EXPR_NAME]));
256 if (expr == NULL)
257 goto err1;
258
259 if (tb[NFTA_EXPR_DATA] &&
260 expr->ops->parse &&
261 expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0)
262 goto err2;
263
264 return expr;
265
266err2:
267 xfree(expr);
268err1:
269 return NULL;
270}
271
272EXPORT_SYMBOL(nftnl_expr_snprintf);
273int nftnl_expr_snprintf(char *buf, size_t remain, const struct nftnl_expr *expr,
274 uint32_t type, uint32_t flags)
275{
276 int ret;
277 unsigned int offset = 0;
278
279 if (remain)
280 buf[0] = '\0';
281
282 if (!expr->ops->output || type != NFTNL_OUTPUT_DEFAULT)
283 return 0;
284
285 ret = expr->ops->output(buf + offset, remain, flags, expr);
286 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
287
288 return offset;
289}
290
291static int nftnl_expr_do_snprintf(char *buf, size_t size, const void *e,
292 uint32_t cmd, uint32_t type, uint32_t flags)
293{
294 return nftnl_expr_snprintf(buf, size, e, type, flags);
295}
296
297EXPORT_SYMBOL(nftnl_expr_fprintf);
298int nftnl_expr_fprintf(FILE *fp, const struct nftnl_expr *expr, uint32_t type,
299 uint32_t flags)
300{
301 return nftnl_fprintf(fp, expr, NFTNL_CMD_UNSPEC, type, flags,
302 nftnl_expr_do_snprintf);
303}